Bio

Clinical Focus


  • Head and neck vascular malformations and anomalies
  • Spinal Intervention for pain
  • Pediatric Neuroradiology
  • Diagnostic Radiology
  • Interventional Oncology
  • Interventional Neuroradiology
  • Endovascular Neurosurgery

Academic Appointments


Administrative Appointments


  • Neuroradiology Fellowship Director, Stanford University School of Medicine (2004 - Present)

Honors & Awards


  • Michael Brothers Memorial Award, Co-investigator, American Society of Neuroradiology (2005)
  • ASSR Mentor Research Award, American Society of Spine Radiology (2003)
  • Best Paper Presentation Award, American Society of Spine Radiology (2004)
  • Outstanding Presentation Award, American Society of Neuroradiology (2002)
  • General Electric/AUR Radiology Research Academic Fellowship, Association of University Radiologists (2000-2002)
  • Cornelius G. Dyke Memorial Award, Co-investigator, American Society of Neuroradiology (2000)
  • Executive Council Award, American Roentgen Ray Society (1999)
  • ASNR/Berlex Basic Science Research Fellow, American Society of Neuroradiology (1997-1998)

Boards, Advisory Committees, Professional Organizations


  • Advisory Committe (Scientific Consultant), Food and Drug Administration (2011 - Present)
  • Board of Directors, Society of Neurointerventional Surgery (2002 - 2010)
  • Editorial Board, American Journal of Neuroradiology (2006 - 2008)
  • Editorial Board, Case Report in Medicine (2010 - Present)
  • Editorial Board, World Journal of Radiology (2013 - Present)

Professional Education


  • Fellowship:University Of Virginia (1999) VA
  • Board Certification: Diagnostic Radiology, American Board of Radiology (1996)
  • Residency:UCLA Health Sciences (1996) CA
  • Internship:University of Washington School of Medicine (1992) WA
  • Medical Education:Brown University - School of Medicine (1991) RI

Research & Scholarship

Clinical Trials


  • Quantifying Collateral Perfusion in Cerebrovascular Disease-Moyamoya Disease and Stroke Patients Not Recruiting

    Quantifying Collateral Perfusion in Cerebrovascular Disease-Moyamoya disease and stroke patients

    Stanford is currently not accepting patients for this trial. For more information, please contact Sandra Dunn, 650-724-8278.

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  • Protected Carotid Artery Stenting in Subjects at High Risk for Carotid Endarterectomy (CEA) (PROTECT) Not Recruiting

    The purpose of this study is to evaluate the long-term safety and efficacy of the Xact™ Rapid Exchange Carotid Stent System used in conjunction with the Emboshield® Pro Rapid Exchange Embolic Protection System (Generation 5) and the Emboshield® BareWire™ Rapid Exchange Embolic Protection System (Generation 3), in the treatment of atherosclerotic carotid artery disease in high-surgical risk subjects.

    Stanford is currently not accepting patients for this trial. For more information, please contact Ronald Dalman, (650) 725 - 5227.

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  • Evaluating Neuroprotection in Aneurysm Coiling Therapy Not Recruiting

    This is a randomized, double-blind, placebo-controlled, single-dose, design investigating the safety, tolerability and efficacy of NA-1, a peptide designed to reduce ischemic brain damage. Up to 200 male and female patients undergoing endovascular repair of brain aneurysm will be dosed with 2.60 mg/kg of NA-1 or placebo as a 10 minute intravenous infusion after completion of the endovascular procedure on Day 1 of the study period. Subjects will undergo interim procedures Days 2-4 and end-of study procedures on Day 30. Standard safety criteria will be analysed. Efficacy endpoints include the ability of NA-1 to: 1) reduce the volume of ischemic embolic strokes, 2) reduce the number of ischemic embolic strokes, 3) reduce vascular cognitive impairment, and 4) reduce the frequency of large strokes induced by the endovascular procedure. The plasma concentrations of NA-1 will also be analyzed.

    Stanford is currently not accepting patients for this trial. For more information, please contact Huy M. Do, MD, 650-723-6767.

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  • Computed Tomography Perfusion (CTP) to Predict Response to Recanalization in Ischemic Stroke Project (CRISP) Recruiting

    The overall goal of the CTP to predict Response to recanalization in Ischemic Stroke Project (CRISP) is to develop a practical tool to identify acute stroke patients who are likely to benefit from endovascular therapy. The project has two main parts. During the first part, the investigators propose to develop a fully automated system (RAPID) for processing of CT Perfusion (CTP) images that will generate brain maps of the ischemic core and penumbra. There will be no patient enrollment in part one of this project. During the second part, the investigators aim to demonstrate that physicians in the emergency setting, with the aid of a fully automated CTP analysis program (RAPID), can accurately predict response to recanalization in stroke patients undergoing revascularization. To achieve this aim the investigators will conduct a prospective cohort study of 240 consecutive stroke patients who will undergo a CTP scan prior to endovascular therapy. The study will be conducted at four sites (Stanford University, St Luke's Hospital, University of Pittsburgh Medical Center, and Emory University/Grady Hospital). Patients will have an early follow-up MRI scan within 12+/-6 hours to assess reperfusion and a late follow-up MRI scan at day 5 to determine the final infarct.

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  • A Randomized, Concurrent Controlled Trial to Assess the Safety and Effectiveness of the Separator 3D as a Component of the Penumbra System in the Revascularization of Large Vessel Occlusion in Acute Ischemic Stroke Recruiting

    This is a prospective, randomized, concurrent controlled, multi-center study. Patients presenting with symptoms of acute ischemic stroke who have evidence of a large vessel (>3mm in diameter) occlusion in the cerebral circulation will be assigned to either the Penumbra System with the Separator 3D or the Penumbra System without the Separator 3D. Each treated patient will be followed and assessed for 3 months after randomization. Up to 164 evaluable patients at up to 50 centers presenting with acute ischemic stroke in vessels accessible to the Penumbra Separator 3D System for revascularization within 8 hours of symptom onset. The hypothesis to be tested is that the safety and effectiveness of the Penumbra System with the Separator 3D for the revascularization of large vessel occlusion is not inferior to the Penumbra System alone.

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  • Phase I Trial of Arsenic Trioxide and Stereotactic Radiotherapy for Recurrent Malignant Glioma Not Recruiting

    To investigate the safety of delivering arsenic trioxide (ATO) in combination with stereotactic radiotherapy in recurrent malignant glioma by performing an open label, Phase I dose escalation trial. Results from this study will provide a basis for further study of ATO combined with radiation therapy as a radiosensitizer for malignant brain tumors in future Phase II studies.

    Stanford is currently not accepting patients for this trial. For more information, please contact Laurie Tupper, (650) 498 - 4143.

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Teaching

2013-14 Courses


Publications

Journal Articles


  • Cerebral angioplasty using the Scepter XC dual lumen balloon for the treatment of vasospasm following intracranial aneurysm rupture. Journal of neurointerventional surgery Heit, J. J., Choudhri, O., Marks, M. P., Dodd, R. L., Do, H. M. 2014

    Abstract

    Cerebral vasospasm following subarachnoid hemorrhage (SAH) results in significant morbidity and mortality. Intra-arterial administration of calcium channel blockers or intracranial angioplasty may be performed when non-invasive medical management fails to prevent neurologic deterioration. Technical improvements in balloon catheters are expected to improve the success and safety of cerebral angioplasty.To describe our initial experience with the new Scepter XC balloon catheter in cerebral vasospasm treatment following SAH.All patients who underwent cerebral angioplasty using the Scepter XC balloon for the treatment of medically refractory cerebral vasospasm after SAH were identified. Patient demographic information, procedural details, and outcome were obtained from electronic medical records.Five consecutive patients undergoing vasospasm treatment with cerebral angioplasty using the Scepter XC were identified. All treated patients had medically refractory vasospasm that was moderate or severe. Angioplasty of the supraclinoid internal carotid artery, the A1 and A2 segments of the anterior cerebral artery, the M1 and M2 segments of the middle cerebral artery, the V4 segment of the vertebral artery, and the basilar artery was performed. All angioplasty procedures were technically successful, and the degree of vasospasm improved significantly following angioplasty. There were no complications related to the cerebral angioplasty procedures.The Scepter XC balloon catheter is safe and effective in the treatment of cerebral vasospasm following SAH. The excellent trackability and stability of the balloon catheter and the extra compliant design of the balloon represent technical advancements in the endovascular armamentarium in the treatment of cerebral vasospasm.

    View details for DOI 10.1136/neurintsurg-2013-011043

    View details for PubMedID 24385556

  • Delayed retraction of the pipeline embolization device and corking failure: pitfalls of pipeline embolization device placement in the setting of a ruptured aneurysm. Neurosurgery McTaggart, R. A., Santarelli, J. G., Marcellus, M. L., Steinberg, G. K., Dodd, R. L., Do, H. M., Marks, M. P. 2013; 72 (2): onsE245-51

    Abstract

    : The safety of flow-diverting stents for the treatment of ruptured intracranial aneurysms is unknown.: A 35-year-old woman with a ruptured dissecting aneurysm of the intradural right vertebral artery and incorporating the right posterior inferior cerebellar artery was treated with a Pipeline Embolization Device (PED). Five days after reconstruction of the diseased right vertebral segment, she was treated for vasospasm, and retraction of the PED was observed, leaving her dissecting aneurysm unprotected. A second PED was placed with coverage of the aneurysm, but vasospasm complicated optimal positioning of the device.: In addition to the potential risks of dual antiplatelet therapy in these patients, this case illustrates 2 pitfalls of flow-diverting devices in vessels in vasospasm: delayed retraction of the device and difficulty positioning the device for deployment in the setting of vasospasm.: ANR, aneurysmPED, Pipeline Embolization DevicePICA, posterior inferior cerebellar arterySAH, subarachnoid hemorrhage.

    View details for DOI 10.1227/NEU.0b013e31827fc9be

    View details for PubMedID 23190640

  • Percutaneous sclerotherapy with ethanolamine oleate for venous malformations of the head and neck. Journal of neurointerventional surgery Alexander, M. D., McTaggart, R. A., Choudhri, O. A., Marcellus, M. L., Do, H. M. 2013

    Abstract

    Venous malformations frequently occur in the head and neck, and they can require treatment for a variety of reasons. Among multiple therapeutic approaches employed, percutaneous sclerotherapy has become one of the most commonly used treatments, with numerous sclerosants successfully utilized. Ethanolamine oleate has approval from the Food and Drug Administration for sclerosis of esophageal varices, and is used by some practitioners for the treatment of venous malformations. This study reports single center results of percutaneous sclerotherapy with ethanolamine oleate to treat venous malformations of the head and neck.Prospectively maintained procedural records were retrospectively reviewed to identify all patients with venous malformations who underwent percutaneous sclerotherapy. The Mulliken and Glowacki classification was used to diagnose venous malformations. Medical records and images were reviewed to record demographic information, lesion characteristics, treatment sessions, and clinical and imaging response. Quantitative volumetric analysis was conducted to augment commonly used poorly reproducible subjective outcome measures. Response was assessed after each session and completion of all percutaneous treatment. A χ(2) analysis was performed to evaluate the effects of the above described characteristics on outcomes.52 interventions were performed for lesions in 26 patients. No complications occurred following any procedures. Response to individual sessions was categorized as excellent following two (3.8%) sessions, good following 45 (86.5%), and fair following four (7.7%) session. No sessions resulted in poor responses. Final results were excellent in two patients (7.7%), good in 22 (84.6%), and fair in two (7.7%). Average lesion volume reduction was 39% following each session, and 61% after treatment completion. Periorbital lesions were significantly less likely than lesions located elsewhere to have good or excellent outcomes. No other lesion or demographic features affected outcomes.Percutaneous sclerotherapy with ethanolamine oleate appears to be safe and effective for the treatment of venous malformations and should be considered when treating these complex lesions. The efficacy of this agent appears to match or exceed that of other sclerosants used for such treatment, and further investigation in prospective controlled research is warranted.

    View details for DOI 10.1136/neurintsurg-2013-010924

    View details for PubMedID 24235099

  • Standard of practice: embolization of ruptured and unruptured intracranial aneurysms. Journal of neurointerventional surgery Patsalides, A., Bulsara, K. R., Hsu, D. P., Abruzzo, T., Narayanan, S., Jayaraman, M. V., Duckwiler, G., Klucznik, R. P., Kelly, M., Hirsch, J. A., Heck, D., Sunshine, J., Frei, D., Alexander, M. J., Do, H. M., Meyers, P. M. 2013; 5 (4): 283-8

    View details for PubMedID 23576604

  • Reversible cerebral vasoconstriction syndrome and bilateral vertebral artery dissection presenting in a patient after cesarean section. Journal of neurointerventional surgery Mitchell, L. A., Santarelli, J. G., Singh, I. P., Do, H. M. 2013

    Abstract

    Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by sudden-onset thunderclap headache and focal neurologic deficits. Once thought to be a rare syndrome, more advanced non-invasive imaging has led to an increase in RCVS diagnosis. Unilateral vertebral artery dissection has been described in fewer than 40% of cases of RCVS. Bilateral vertebral artery dissection has rarely been reported. We describe the case of a patient with RCVS and bilateral vertebral artery dissection presenting with an intramedullary infarct treated successfully with medical management and careful close follow-up. This rare coexistence should be recognized as the treatment differs.

    View details for PubMedID 23385005

  • Multimodality Evaluation of Dural Arteriovenous Fistula with CT Angiography, MR with Arterial Spin Labeling, and Digital Subtraction Angiography: Case Report. Journal of neuroimaging : official journal of the American Society of Neuroimaging Alexander, M., McTaggart, R., Santarelli, J., Fischbein, N., Marks, M., Zaharchuk, G., Do, H. 2013

    Abstract

    Dural arteriovenous fistulae (DAVF) are cerebrovascular lesions with pathologic shunting into the venous system from arterial feeders. Digital subtraction angiography (DSA) has long been considered the gold standard for diagnosis, but advances in noninvasive imaging techniques now play a role in the diagnosis of these complex lesions. Herein, we describe the case of a patient with right-side pulsatile tinnitus and DAVF diagnosed using computed tomography angiography, magnetic resonance with arterial spin labeling, and DSA. Implications for imaging analysis of DAVFs and further research are discussed.

    View details for PubMedID 23746119

  • Reversible cerebral vasoconstriction syndrome and bilateral vertebral artery dissection presenting in a patient after cesarean section. BMJ case reports Mitchell, L. A., Santarelli, J. G., Singh, I. P., Do, H. M. 2013; 2013

    Abstract

    Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by sudden-onset thunderclap headache and focal neurologic deficits. Once thought to be a rare syndrome, more advanced non-invasive imaging has led to an increase in RCVS diagnosis. Unilateral vertebral artery dissection has been described in fewer than 40% of cases of RCVS. Bilateral vertebral artery dissection has rarely been reported. We describe the case of a patient with RCVS and bilateral vertebral artery dissection presenting with an intramedullary infarct treated successfully with medical management and careful close follow-up. This rare coexistence should be recognized as the treatment differs.

    View details for DOI 10.1136/bcr-2012-010521

    View details for PubMedID 23354867

  • Reporting standards for endovascular chemotherapy of head, neck and CNS tumors. Journal of neurointerventional surgery Fraser, J. F., Hussain, M. S., Eskey, C., Abruzzo, T., Bulsara, K., English, J., Blackham, K., Do, H. M., Prestigiacomo, C., Jayaraman, M. V., Patsalides, A., Kelly, M., Sunshine, J. L., Meyers, P. 2013

    Abstract

    The goal of this article is to provide expert consensus recommendations for reporting standards, terminology and definitions when reporting on neurointerventional chemotherapy administration for head and neck tumors. These criteria may be used to design clinical trials, to provide definitions for patient stratification and to permit robust analysis of published data.This publication represents a consensus document by the Society for Neurointerventional Surgery. A PubMed search was conducted and included articles published in 2002-2011, with the search strategy designed to identify all studies of intra-arterial chemotherapy for tumors of neck and head. Articles were evaluated for evidence class, and recommendations were made using guidelines for evidence-based medicine proposed by a joint committee of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons. Specifically, technical methods, outcome variables and reported complications were highlighted.Thirty-five publications were included in the review. While most studies represent class III evidence, there was sufficient concordance to justify level 2 recommendations regarding technical methods for administration of intra-arterial chemotherapy. The data also support level 2 recommendations regarding reporting of particular outcome variables subsumed within broad categories entitled 'Procedure-related', 'Disease control' and 'Survival'. The data support recommendations for the reporting of access site-related, neurologic, head and neck, ocular, hematologic and systemic complications, and also complications related to the percutaneous access site.Intra-arterial chemotherapy is a growing field in interventional neuroradiology. It is important to adopt uniform technical and reporting standards that will allow cross-publication comparisons and facilitate homogeneous practice standards. Published data support such standards, which are vital for the consistent evaluation of future published research.

    View details for PubMedID 23828325

  • Standards of practice and reporting standards for carotid artery angioplasty and stenting. Journal of neurointerventional surgery Powers, C. J., Hirsch, J. A., Hussain, M. S., Patsalides, A. T., Blackham, K. A., Narayanan, S., Lee, S. K., Fraser, J. F., Bulsara, K. R., Prestigiacomo, C. J., Gandhi, C. D., Abruzzo, T., Do, H. M., Meyers, P. M., Albuquerque, F. C., Frei, D., Kelly, M. E., Pride, G. L., Jayaraman, M. V. 2013

    View details for DOI 10.1136/neurintsurg-2013-011013

    View details for PubMedID 24198273

  • Vertebral augmentation: report of the Standards and Guidelines Committee of the Society of NeuroInterventional Surgery. Journal of neurointerventional surgery Chandra, R. V., Meyers, P. M., Hirsch, J. A., Abruzzo, T., Eskey, C. J., Hussain, M. S., Lee, S. K., Narayanan, S., Bulsara, K. R., Gandhi, C. D., Do, H. M., Prestigiacomo, C. J., Albuquerque, F. C., Frei, D., Kelly, M. E., Mack, W. J., Pride, G. L., Jayaraman, M. V. 2013

    View details for DOI 10.1136/neurintsurg-2013-011012

    View details for PubMedID 24198272

  • Percutaneous sclerotherapy with ethanolamine oleate for lymphatic malformations of the head and neck. Journal of neurointerventional surgery Alexander, M. D., McTaggart, R. A., Choudhri, O. A., Marcellus, M. L., Do, H. M. 2013

    Abstract

    Lymphatic malformations are low flow congenital lesions that frequently occur in the head and neck, and often require treatment. Multiple therapeutic modalities exist, including percutaneous sclerotherapy, which has been performed successfully with numerous sclerosants. Few data exist on use of ethanolamine oleate to treat lymphatic malformations. This study reports single center results using this agent to treat lymphatic malformations of the head and neck.Prospectively maintained procedural records were retrospectively reviewed to identify all patients with lymphatic malformations who underwent percutaneous sclerotherapy. The Mulliken and Glowacki classification was used to diagnose lymphatic malformations. Medical records and images were reviewed to record demographic information, lesion characteristics, treatment sessions, and clinical and imaging response. Lesions and outcomes were evaluated with both qualitative and quantitative volumetric analysis. Response was assessed after each session and after all sessions in those patients undergoing more than one intervention, and χ(2) analysis was performed to evaluate the effects of lesion and demographic characteristics on outcomes.12 interventions were performed for lesions in 10 patients. No procedural complications occurred following any procedures. Four (40.0%) patients had an excellent result after treatment, which was accomplished in one session for each of these lesions. Four (40.0%) had good results. One (10.0%) had a fair result after three sessions. One (10.0%) patient with an indeterminate syndrome with multiple congenital anomalies had a poor response following treatment. The family decided to withdraw care, and the airway was compromised. Average lesion volume reduction was 28% for all lesions and 42% when excluding the lesion for which future treatments were declined. Purely macrocystic lesions were more likely to have an excellent response to treatment than lesions with both macrocystic and microcystic components.Percutaneous sclerotherapy using ethanolamine oleate to treat lymphatic malformations of the head and neck appears safe and efficacious. This agent should be considered when treating these complex lesions, particularly those that are exclusively macrocystic. Further investigation of such treatments should evaluate this agent alongside the many others currently utilized.

    View details for DOI 10.1136/neurintsurg-2013-010925

    View details for PubMedID 24153336

  • A Simplified Method for Administration of Intra-Arterial Nicardipine for Vasospasm With Cervical Catheter Infusion NEUROSURGERY Pandey, P., Steinberg, G. K., Dodd, R., Do, H. M., Marks, M. P. 2012; 71: 77-85

    Abstract

    Cerebral vasospasm is a major cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage. Nicardipine has previously been used to treat vasospasm through superselective intracranial microcatheter injections.To evaluate a simple method of treatment of vasospasm with slow infusion of nicardipine from a cervical catheter.Twenty-seven patients with symptomatic vasospasm were treated over 4 years with cervical catheter infusions. Nicardipine was infused at 20 mg/h for 30 to 60 minutes. Angioplasty was used in severe cases at the operator's discretion. Outcome at discharge and follow-up was evaluated with Glasgow Outcome Scale.Twenty-seven patients (17 women, 12 men) received intra-arterial therapy for vasospasm. Vasospasm treatment was done at a mean post-hemorrhage date of 7.2 days (range, 4-15 days). They underwent 48 sessions of treatment (mean, 1.8 per patient) in 72 separate arterial territories. Twelve patients underwent multiple treatments. The mean dose used per session was 19.2 mg (range, 5-50 mg). Four patients underwent angioplasty for severe vasospasm. Twenty-two patients (81.5%) had clinical improvement after the infusion. Angiographic improvement was seen in 86.1% of the vessels analyzed, which had moderate or severe spasm before infusion. Overall, 17 patients (62.9%) had good outcome (Glasgow Outcome Scale score, 4 and 5) at discharge, 11 had poor outcome, and 1 patient died. Follow-up was available in 19 patients, and 18 were doing well (Glasgow Outcome Scale score, 4 and 5).Intra-arterial nicardipine is an effective and safe treatment for cerebral vasospasm. In most patients, infusion can be performed from the cervical catheter, with microcatheter infusion and angioplasty reserved for the more severe and resistant cases.

    View details for DOI 10.1227/NEU.0b013e3182426257

    View details for Web of Science ID 000308328300032

    View details for PubMedID 22105209

  • Head, neck, and brain tumor embolization guidelines JOURNAL OF NEUROINTERVENTIONAL SURGERY Duffis, E. J., Gandhi, C. D., Prestigiacomo, C. J., Abruzzo, T., Albuquerque, F., Bulsara, K. R., Derdeyn, C. P., Fraser, J. F., Hirsch, J. A., Hussain, M. S., Do, H. M., Jayaraman, M. V., Meyers, P. M., Narayanan, S. 2012; 4 (4): 251-255

    Abstract

    Management of vascular tumors of the head, neck, and brain is often complex and requires a multidisciplinary approach. Peri-operative embolization of vascular tumors may help to reduce intra-operative bleeding and operative times and have thus become an integral part of the management of these tumors. Advances in catheter and non-catheter based techniques in conjunction with the growing field of neurointerventional surgery is likely to expand the number of peri-operative embolizations performed. The goal of this article is to provide consensus reporting standards and guidelines for embolization treatment of vascular head, neck, and brain tumors.This article was produced by a writing group comprised of members of the Society of Neurointerventional Surgery. A computerized literature search using the National Library of Medicine database (Pubmed) was conducted for relevant articles published between 1 January 1990 and 31 December 2010. The article summarizes the effectiveness and safety of peri-operative vascular tumor embolization. In addition, this document provides consensus definitions and reporting standards as well as guidelines not intended to represent the standard of care, but rather to provide uniformity in subsequent trials and studies involving embolization of vascular head and neck as well as brain tumors.Peri-operative embolization of vascular head, neck, and brain tumors is an effective and safe adjuvant to surgical resection. Major complications reported in the literature are rare when these procedures are performed by operators with appropriate training and knowledge of the relevant vascular and surgical anatomy. These standards may help to standardize reporting and publication in future studies.

    View details for DOI 10.1136/neurintsurg-2012-010350

    View details for Web of Science ID 000306026400006

    View details for PubMedID 22539531

  • Multimodality management of Spetzler-Martin Grade III arteriovenous malformations JOURNAL OF NEUROSURGERY Pandey, P., Marks, M. P., Harraher, C. D., Westbroek, E. M., Chang, S. D., Do, H. M., Levy, R. P., Dodd, R. L., Steinberg, G. K. 2012; 116 (6): 1279-1288

    Abstract

    Grade III arteriovenous malformations (AVMs) are diverse because of their variations in size (S), location in eloquent cortex (E), and presence of central venous drainage (V). Because they may have implications for management and outcome, the authors evaluated these variations in the present study.Between 1984 and 2010, 100 patients with Grade III AVMs were treated. The AVMs were categorized by Spetzler-Martin characteristics as follows: Type 1 = S1E1V1, Type 2 = S2E1V0, Type 3 = S2E0V1, and Type 4 = S3E0V0. The occurrence of a new neurological deficit, functional status (based on modified Rankin Scale [mRS] score) at discharge and follow-up, and radiological obliteration were correlated with demographic and morphological characteristics.One hundred patients (49 female and 51 male; age range 5-68 years, mean 35.8 years) were evaluated. The size of AVMs was less than 3 cm in 28 patients, 3-6 cm in 71, and greater than 6 cm in 1; 86 AVMs were located in eloquent cortex and 38 had central drainage. The AVMs were Type 1 in 28 cases, Type 2 in 60, Type 3 in 11, and Type 4 in 1. The authors performed embolization in 77 patients (175 procedures), surgery in 64 patients (74 surgeries), and radiosurgery in 49 patients (44 primary and 5 postoperative). The mortality rate following the management of these AVMs was 1%. Fourteen patients (14%) had new neurological deficits, with 5 (5%) being disabling (mRS score > 2) and 9 (9%) being nondisabling (mRS score ? 2) events. Patients with Type 1 AVMs (small size) had the best outcome, with 1 (3.6%) in 28 having a new neurological deficit, compared with 72 patients with larger AVMs, of whom 13 (18.1%) had a new neurological deficit (p < 0.002). Older age (> 40 years), malformation size > 3 cm, and nonhemorrhagic presentation predicted the occurrence of new deficits (p < 0.002). Sex, eloquent cortex, and venous drainage did not confer any benefit. In 89 cases follow-up was adequate for data to be included in the obliteration analysis. The AVM was obliterated in 78 patients (87.6%), 69 of them (88.5%) demonstrated on angiography and 9 on MRI /MR angiography. There was no difference between obliteration rates between different types of AVMs, size, eloquence, and drainage. Age, sex, and clinical presentation also did not predict obliteration.Multimodality management of Grade III AVMs results in a high rate of obliteration, which was not influenced by size, venous drainage, or eloquent location. However, the development of new neurological deficits did correlate with size, whereas eloquence and venous drainage did not affect the neurological complication rate. The authors propose subclassifying the Grade III AVMs according to their size (< 3 and ? 3 cm) to account for treatment risk.

    View details for DOI 10.3171/2012.3.JNS111575

    View details for Web of Science ID 000304294000022

    View details for PubMedID 22482792

  • Vascular tortuosity: a mathematical modeling perspective JOURNAL OF PHYSIOLOGICAL SCIENCES Hathout, L., Do, H. M. 2012; 62 (2): 133-145

    Abstract

    Although vascular tortuosity is a ubiquitous phenomenon, almost no mathematical models exist to describe its shape. Given that the shape of tortuous vessel curves seems fairly uniform across orders of magnitude of vessel size and across vast differences in anatomic substrata, it is hypothesized that the shape of tortuosity is not purely random but rather is governed by physical principles. We present a mathematical model of tortuosity based on optimality principles, and show how this model can potentially be used to distinguish physiologic tortuosity from abnormal tortuosity which may exist in disease states. Using the calculus of variations, a model of tortuosity has been developed which minimizes average curvature per unit length. The model is tested against curves in normal vessels and in diseased vessels in a case of Fabry's disease. It is found that the theoretical model provides a good fit for normal vessel tortuosity. This suggests that blood vessels obey optimality principles, and curve in such a way as to minimize average curvature. The model may also be able to distinguish physiologic tortuosity from abnormal tortuosity found in disease states.

    View details for DOI 10.1007/s12576-011-0191-6

    View details for Web of Science ID 000300774300006

    View details for PubMedID 22252461

  • Management of Pediatric Intracranial Arteriovenous Malformations: Experience With Multimodality Therapy NEUROSURGERY Darsaut, T. E., Guzman, R., Marcellus, M. L., Edwards, M. S., Tian, L., Do, H. M., Chang, S. D., Levy, R. P., Adler, J. R., Marks, M. P., Steinberg, G. K. 2011; 69 (3): 540-556

    Abstract

    Successful management of pediatric arteriovenous malformations (AVMs) often requires a balanced application of embolization, surgery, and radiosurgery.To describe our experience treating pediatric AVMs.We analyzed 120 pediatric patients (< 18 years of age) with AVMs treated with various combinations of radiosurgery, surgery, and endovascular techniques.Between 1985 and 2009, 76 children with low Spetzler-Martin grade (1-3) and 44 with high-grade (4-5) AVMs were treated. Annual risk of hemorrhage from presentation to initial treatment was 4.0%, decreasing to 3.2% after treatment initiation until confirmed obliteration. Results for AVM obliteration were available in 101 patients. Initial single-modality therapy led to AVM obliteration in 51 of 67 low-grade (76%) and 3 of 34 high-grade (9%) AVMs, improving to 58 of 67 (87%) and 9 of 34 (26%), respectively, with further treatment. Mean time to obliteration was 1.8 years for low-grade and 6.4 years for high-grade AVMs. Disabling neurological complications occurred in 4 of 77 low-grade (5%) and 12 of 43 high-grade (28%) AVMs. At the final clinical follow-up (mean, 9.2 years), 48 of 67 patients (72%) with low-grade lesions had a modified Rankin Scale score (mRS) of 0 to 1 compared with 12 of 34 patients (35%) with high-grade AVMs. On multivariate analysis, significant risk factors for poor final clinical outcome (mRS ? 2) included baseline mRS ? 2 (odds ratio, 9.51; 95% confidence interval, 3.31-27.37; P < .01), left-sided location (odds ratio, 3.03; 95% confidence interval, 1.11-8.33; P = .03), and high AVM grade (odds ratio, 4.35; 95% confidence interval, 1.28-14.28; P = .02).Treatment of pediatric AVMs with multimodality therapy can substantially improve obliteration rates and may decrease AVM hemorrhage rates. The poor natural history and risks of intervention must be carefully considered when deciding to treat high-grade pediatric AVMs.

    View details for DOI 10.1227/NEU.0b013e3182181c00

    View details for Web of Science ID 000293586200005

    View details for PubMedID 21430584

  • Arterial Spin-Labeling MRI Can Identify the Presence and Intensity of Collateral Perfusion in Patients With Moyamoya Disease STROKE Zaharchuk, G., Do, H. M., Marks, M. P., Rosenberg, J., Moseley, M. E., Steinberg, G. K. 2011; 42 (9): 2485-U183

    Abstract

    Determining the presence and adequacy of collateral blood flow is important in cerebrovascular disease. Therefore, we explored whether a noninvasive imaging modality, arterial spin labeling (ASL) MRI, could be used to detect the presence and intensity of collateral flow using digital subtraction angiography (DSA) and stable xenon CT cerebral blood flow as gold standards for collaterals and cerebral blood flow, respectively.ASL and DSA were obtained within 4 days of each other in 18 patients with Moyamoya disease. Two neurointerventionalists scored DSA images using a collateral grading scale in regions of interest corresponding to ASPECTS methodology. Two neuroradiologists similarly scored ASL images based on the presence of arterial transit artifact. Agreement of ASL and DSA consensus scores was determined, including kappa statistics. In 15 patients, additional quantitative xenon CT cerebral blood flow measurements were performed and compared with collateral grades.The agreement between ASL and DSA consensus readings was moderate to strong, with a weighted kappa value of 0.58 (95% confidence interval, 0.52-0.64), but there was better agreement between readers for ASL compared with DSA. Sensitivity and specificity for identifying collaterals with ASL were 0.83 (95% confidence interval, 0.77-0.88) and 0.82 (95% confidence interval, 0.76-0.87), respectively. Xenon CT cerebral blood flow increased with increasing DSA and ASL collateral grade (P<0.05).ASL can noninvasively predict the presence and intensity of collateral flow in patients with Moyamoya disease using DSA as a gold standard. Further study of other cerebrovascular diseases, including acute ischemic stroke, is warranted.

    View details for DOI 10.1161/STROKEAHA.111.61646

    View details for Web of Science ID 000294342800031

    View details for PubMedID 21799169

  • Intraoperative Angiography for Cranial Dural Arteriovenous Fistula AMERICAN JOURNAL OF NEURORADIOLOGY Pandey, P., Steinberg, G. K., Westbroek, E. M., Dodd, R., Do, H. M., Marks, M. P. 2011; 32 (6): 1091-1095

    Abstract

    IA is a valuable adjunct during surgery for a variety of neurovascular diseases; however, there are no reported series describing IA for DAVFs. This study was undertaken to evaluate the safety and efficacy of IA for DAVFs.A retrospective review of DAVF surgical cases during a 20-year period was conducted, and cases with IA were evaluated. Clinical details, surgical and angiographic findings, and postoperative outcomes were reviewed. The incidence of residual fistula on IAs, the utility of the surgical procedure, and the incidence of false-negative findings on IA were also determined.IA was performed in 29 patients (31 DAVFs) for DAVFs. The distribution of the fistulas was the following: transverse-sigmoid (n = 9), tentorial (n = 6), torcular (n = 3), cavernous sinus (n = 4), SSS (n = 4), foramen magnum (n = 3), and temporal-middle fossa (n = 2). Twelve patients had undergone prior embolization, while 6 patients had unsuccessful embolization procedures. Thirty-eight surgeries were performed for DAVF in 29 patients, and IA was performed in 34 surgeries. Forty-four angiographic procedures were performed in the 34 surgeries. Nine patients underwent multiple angiographies. In 11 patients (37.9%), IA revealed residual fistula after the surgeon determined that no lesion remained. This led to further exploration at the same sitting in 10 patients, while in 1 patient, further surgery was performed at a later date. False-negative findings on IA occurred in 3 patients (10.7%).IA is an important adjunct in surgery for DAVF. In this series, it resulted in further surgical treatment in 37.9% of patients. However, there was a 10% false-negative rate, which justified subsequent postoperative angiography.

    View details for DOI 10.3174/ajnr.A2443

    View details for Web of Science ID 000292066600024

    View details for PubMedID 21622580

  • Predictors of Clinical and Angiographic Outcome After Surgical or Endovascular Therapy of Very Large and Giant Intracranial Aneurysms NEUROSURGERY Darsaut, T. E., Darsaut, N. M., Chang, S. D., Silverberg, G. D., Shuer, L. M., Tian, L., Dodd, R. L., Do, H. M., Marks, M. P., Steinberg, G. K. 2011; 68 (4): 903-915

    Abstract

    Risk factors for poor outcome in the treatment of very large (?20-24 mm) and giant (?25 mm) intracranial aneurysms remain incompletely defined.To present an aggregate clinical series detailing a 24-year experience with very large and giant aneurysms to identify and assess the relative importance of various patient, aneurysm, and treatment-specific characteristics associated with clinical and angiographic outcomes.The authors retrospectively identified 184 aneurysms measuring 20 mm or larger (85 very large, 99 giant) treated at Stanford University Medical Center between 1984 and 2008. Clinical data including age, presentation, and modified Rankin Scale (mRS) score were recorded, along with aneurysm size, location, and morphology. Type of treatment was noted and clinical outcome measured using the mRS score at final follow-up. Angiographic outcomes were completely occluded, occluded with residual neck, partly obliterated, or patent with modified flow.After multivariate analysis, risk factors for poor clinical outcome included a baseline mRS score of 2 or higher (odds ratio [OR], 0.23; 95% confidence interval [CI]: 0.08-0.66; P = .01), aneurysm size of 25 mm or larger (OR, 3.32; 95% CI: 1.51-7.28; P < .01), and posterior circulation location (OR, 0.18; 95% CI: 0.07-0.43; P < .01). Risk factors for incomplete angiographic obliteration included fusiform morphology (OR, 0.25; 95% CI: 0.10-0.66; P < .01), posterior circulation location (OR, 0.33; 95% CI: 0.13-0.83; P = .02), and endovascular treatment (OR, 0.14; 95% CI: 0.06-0.32; P < .01). Patients with incompletely occluded aneurysms experienced higher rates of posttreatment subarachnoid hemorrhage and had increased mortality compared with those with completely obliterated aneurysms.Our results suggest that patients with poor baseline functional status, giant aneurysms, and aneurysms in the posterior circulation had a significantly higher proportion of poor outcomes at final follow-up. Fusiform morphology, posterior circulation location, and endovascular treatment were risk factors for incompletely obliterated aneurysms.

    View details for DOI 10.1227/NEU.0b013e3182098ad0

    View details for Web of Science ID 000288123100038

    View details for PubMedID 21221025

  • TECHNIQUE FOR TARGETING ARTERIOVENOUS MALFORMATIONS USING FRAMELESS IMAGE-GUIDED ROBOTIC RADIOSURGERY INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Hristov, D., Liu, L., Adler, J. R., Gibbs, I. C., Moore, T., Sarmiento, M., Chang, S. D., Dodd, R., Marks, M., Do, H. M. 2011; 79 (4): 1232-1240

    Abstract

    To integrate three-dimensional (3D) digital rotation angiography (DRA) and two-dimensional (2D) digital subtraction angiography (DSA) imaging into a targeting methodology enabling comprehensive image-guided robotic radiosurgery of arteriovenous malformations (AVMs).DRA geometric integrity was evaluated by imaging a phantom with embedded markers. Dedicated DSA acquisition modes with preset C-arm positions were configured. The geometric reproducibility of the presets was determined, and its impact on localization accuracy was evaluated. An imaging protocol composed of anterior-posterior and lateral DSA series in combination with a DRA run without couch displacement between acquisitions was introduced. Software was developed for registration of DSA and DRA (2D-3D) images to correct for: (a) small misalignments of the C-arm with respect to the estimated geometry of the set positions and (b) potential patient motion between image series. Within the software, correlated navigation of registered DRA and DSA images was incorporated to localize AVMs within a 3D image coordinate space. Subsequent treatment planning and delivery followed a standard image-guided robotic radiosurgery process.DRA spatial distortions were typically smaller than 0.3 mm throughout a 145-mm × 145-mm × 145-mm volume. With 2D-3D image registration, localization uncertainties resulting from the achievable reproducibility of the C-arm set positions could be reduced to about 0.2 mm. Overall system-related localization uncertainty within the DRA coordinate space was 0.4 mm. Image-guided frameless robotic radiosurgical treatments with this technique were initiated.The integration of DRA and DSA into the process of nidus localization increases the confidence with which radiosurgical ablation of AVMs can be performed when using only an image-guided technique. Such an approach can increase patient comfort, decrease time pressure on clinical and technical staff, and possibly reduce the number of cerebral angiograms needed for a particular patient.

    View details for DOI 10.1016/j.ijrobp.2010.05.015

    View details for Web of Science ID 000288471500036

    View details for PubMedID 20801584

  • CT Angiography as a Screening Tool for Dural Arteriovenous Fistula in Patients with Pulsatile Tinnitus: Feasibility and Test Characteristics AMERICAN JOURNAL OF NEURORADIOLOGY Narvid, J., Do, H. M., Blevins, N. H., Fischbein, N. J. 2011; 32 (3): 446-453

    Abstract

    The diagnosis of intracranial DAVF with noninvasive cross-sectional imaging such as CTA is challenging. We sought to determine the sensitivity and specificity of CTA compared with cerebral angiography for DAVF in patients presenting with PT.Following approval of the institutional review board, we reviewed all patients who underwent CTA for PT from 2004 to 2009 and collected clinical and imaging data. Seven patients with PT and proved DAVF and 7 age- and sex-matched control patients with PT but no DAVF composed the study group. CTA images were blindly interpreted by 2 experienced neuroradiologists for the presence of 5 variables: asymmetric arterial feeding vessels, "shaggy" appearance of a dural venous sinus, transcalvarial venous channels, asymmetric venous collaterals, and abnormal size and number of cortical veins. Asymmetric attenuation of jugular veins was additionally assessed.The presence of arterial feeders showed good test characteristics for screening, with a sensitivity of 86% (95% CI, 42-99) and a specificity of 100% (95% CI, 52-100). A shaggy sinus or tentorium was highly specific: sensitivity of 42% (95% CI, 11-79) and specificity of 100% (95% CI, 56-100). The presence of transcalvarial venous channels demonstrated a poor sensitivity of 29% (95% CI, 5-70) but a high specificity 86% (95% CI, 42-99). CT attenuation of the jugular veins showed statistically significant asymmetry in the DAVF group versus the control group (P < .05).CTA can be used to screen for DAVF in patients with PT. The presence of asymmetrically visible and enlarged arterial feeding vessels has a high sensitivity and specificity for the diagnosis of DAVF.

    View details for DOI 10.3174/ajnr.A2328

    View details for Web of Science ID 000288639800007

    View details for PubMedID 21402614

  • Enucleated eyes after failed intra-arterial infusion of chemotherapy for unilateral retinoblastoma: histopathologic evaluation of vitreous seeding. Clinical ophthalmology (Auckland, N.Z.) Kim, J., Do, H., Egbert, P. 2011; 5: 1655-1658

    Abstract

    Selective intra-arterial chemotherapy (IAC) has been adopted by many ocular oncology centers to treat advanced intraocular retinoblastoma. In this report, we describe two patients with unilateral intraocular retinoblastoma and persistent vitreous seeding, who were treated with IAC after failed systemic chemotherapy. Despite multiple sessions and increasing dosage of drug delivery, vitreous seeding in these cases failed to respond to IAC, and ultimately both eyes were enucleated for tumor control. Based on the histopathologic findings in these two cases, IAC appears to have limitations in treating persistent vitreous seeding in eyes which have failed systemic chemotherapy. Possible causes for failure of IAC to treat persistent vitreous seeding include poor vitreous penetration, inactive state of tumor seeds within the avascular vitreous cavity, and chemotherapeutic drug resistance.

    View details for DOI 10.2147/OPTH.S24318

    View details for PubMedID 22174572

  • Frameless image guided robotic radiosurgery of arteriovenous malformation localized on spatially correlated digital subtraction and C-arm CT angiography images JOURNAL OF NEUROINTERVENTIONAL SURGERY Hristov, D., Adler, J. R., Gibbs, I. C., Dodd, R., Marks, M., Chang, S. D., Do, H. M. 2010; 2 (3): 252-254

    Abstract

    A case is reported of frameless image guided robotic radiosurgery for an arteriovenous malformation (AVM). C-arm CT (CACT) and concurrent digital subtraction angiography images were used for AVM localization within the CACT volume. Treatment planning was performed on CT images registered with the CACT dataset. During delivery, a robotic linear accelerator tracked the target based on localization with frequent stereoscopic x-ray imaging. This case demonstrates that a frameless approach to AVM radiosurgery is possible.

    View details for DOI 10.1136/jnis.2009.001941

    View details for Web of Science ID 000281357900019

    View details for PubMedID 21990637

  • Facet Pain in Thoracic Compression Fractures PAIN MEDICINE Mitra, R., Do, H., Alamin, T., Cheng, I. 2010; 11 (11): 1674-1677

    Abstract

    To determine if thoracic facet joints may be a significant secondary pain generator in patients with compression fractures. Traditionally, pain from vertebral compression fractures has been attributed to vertebral body itself. Compression fractures have been shown to increase thoracic kyphosis and thereby increase the thoracic flexion moment; these changes eventually increase the shear stress on the posterior elements.We present a small case series of patients with thoracic compression fractures managed with intra-articular facet injections.Tertiary care academic medical center.Two patients with thoracic compression fractures.The subjects received fluoroscopically guided thoracic facet steroid injections for pain management.Change in verbal analog pain score.Patients with thoracic compression fractures received significant long-lasting relief after receiving fluoroscopically guided intra-articular injections.Facet joints may be abnormally stressed due to the increasing thoracic flexion moment in anterior compression fractures, which may serve as a secondary pain generator; intra-articular facet blocks may be an alternative to vertebroplasty.

    View details for Web of Science ID 000283989800011

    View details for PubMedID 21029349

  • Should CT Angiography Be Routinely Used in Patients Suspected of Having Aneurysmal Subarachnoid Hemorrhage? No! RADIOLOGY Jayaraman, M. V., Haas, R. A., Do, H. M., Meyers, P. M. 2010; 254 (1): 314-315

    View details for DOI 10.1148/radiol.09091614

    View details for Web of Science ID 000273820400040

    View details for PubMedID 20032163

  • Clinical outcome after 450 revascularization procedures for moyamoya disease JOURNAL OF NEUROSURGERY Guzman, R., Lee, M., Achrol, A., Bell-Stephens, T., Kelly, M., Do, H. M., Marks, M. P., Steinberg, G. K. 2009; 111 (5): 927-935

    Abstract

    Moyamoya disease (MMD) is a rare cerebrovascular disease mainly described in the Asian literature. To address a lack of data on clinical characteristics and long-term outcomes in the treatment of MMD in North America, the authors analyzed their experience at Stanford University Medical Center. They report on a consecutive series of patients treated for MMD and detail their demographics, clinical characteristics, and long-term surgical outcomes.Data obtained in consecutive series of 329 patients with MMD treated microsurgically by the senior author (G.K.S.) between 1991 and 2008 were analyzed. Demographic, clinical, and surgical data were prospectively gathered and neurological outcomes assessed in postoperative follow-up using the modified Rankin Scale. Association of demographic, clinical, and surgical data with postoperative outcome was assessed by chi-square, uni- and multivariate logistic regression, and Kaplan-Meier survival analyses.The authors treated a total of 233 adult patients undergoing 389 procedures (mean age 39.5 years) and 96 pediatric patients undergoing 168 procedures (mean age 10.1 years). Direct revascularization technique was used in 95.1% of adults and 76.2% of pediatric patients. In 264 patients undergoing 450 procedures (mean follow-up 4.9 years), the surgical morbidity rate was 3.5% and the mortality rate was 0.7% per treated hemisphere. The cumulative 5-year risk of perioperative or subsequent stroke or death was 5.5%. Of the 171 patients presenting with a transient ischemic attack, 91.8% were free of transient ischemic attacks at 1 year or later. Overall, there was a significant improvement in quality of life in the cohort as measured using the modified Rankin Scale (p < 0.0001).Revascularization surgery in patients with MMD carries a low risk, is effective at preventing future ischemic events, and improves quality of life. Patients in whom symptomatic MMD is diagnosed should be offered revascularization surgery.

    View details for DOI 10.3171/2009.4.JNS081649

    View details for Web of Science ID 000271375500012

    View details for PubMedID 19463046

  • Multimodality treatment of posterior fossa arteriovenous malformations JOURNAL OF NEUROSURGERY Kelly, M. E., Guzman, R., Sinclair, J., Bell-Stephens, T. E., Bower, R., Hamilton, S., Marks, M. P., Do, H. M., Chang, S. D., Adler, J. R., Levy, R. P., Steinberg, G. K. 2008; 108 (6): 1152-1161

    Abstract

    Posterior fossa arteriovenous malformations (AVMs) are relatively uncommon and often difficult to treat. The authors present their experience with multimodality treatment of 76 posterior fossa AVMs, with an emphasis on Spetzler-Martin Grades III-V AVMs.Seventy-six patients with posterior fossa AVMs treated with radiosurgery, surgery, and endovascular techniques were analyzed.Between 1982 and 2006, 36 patients with cerebellar AVMs, 33 with brainstem AVMs, and 7 with combined cerebellar-brainstem AVMs were treated. Natural history data were calculated for all 76 patients. The risk of hemorrhage from presentation until initial treatment was 8.4% per year, and it was 9.6% per year after treatment and before obliteration. Forty-eight patients had Grades III-V AVMs with a mean follow-up of 4.8 years (range 0.1-18.4 years, median 3.1 years). Fifty-two percent of patients with Grades III-V AVMs had complete obliteration at the last follow-up visit. Three (21.4%) of 14 patients were cured with a single radiosurgery treatment, and 4 (28.6%) of 14 with 1 or 2 radiosurgery treatments. Twenty-one (61.8%) of 34 patients were cured with multimodality treatment. The mean Glasgow Outcome Scale (GOS) score after treatment was 3.8. Multivariate analysis performed in the 48 patients with Grades III-V AVMs showed radiosurgery alone to be a negative predictor of cure (p = 0.0047). Radiosurgery treatment alone was not a positive predictor of excellent clinical outcome (GOS Score 5; p > 0.05). Nine (18.8%) of 48 patients had major neurological complications related to treatment.Single-treatment radiosurgery has a low cure rate for posterior fossa Spetzler-Martin Grades III-V AVMs. Multimodality therapy nearly tripled this cure rate, with an acceptable risk of complications and excellent or good clinical outcomes in 81% of patients. Radiosurgery alone should be used for intrinsic brainstem AVMs, and multimodality treatment should be considered for all other posterior fossa AVMs.

    View details for DOI 10.3171/JNS/2008/108/6/1152

    View details for Web of Science ID 000256245300024

    View details for PubMedID 18518720

  • Experimental study of intracranial hematoma detection with flat panel detector C-arm CT AMERICAN JOURNAL OF NEURORADIOLOGY Arakawa, H., Marks, M. P., Do, H. M., Bouley, D. M., Strobel, N., Moore, T., Fahrig, R. 2008; 29 (4): 766-772

    Abstract

    Intracranial hemorrhage is a commonly acknowledged complication of interventional neuroradiology procedures, and the ability to image hemorrhage at the time of the procedure would be very beneficial. A new C-arm system with 3D functionality extends the capability of C-arm imaging to include soft-tissue applications by facilitating the detection of low-contrast objects. We evaluated its ability to detect small intracranial hematomas in a swine model.Intracranial hematomas were created in 7 swine by autologous blood injection of various hematocrits (19%-37%) and volumes (1.5-5 mL). Four animals received intravascular contrast before obtaining autologous blood (group 1), and 3 did not (group 2). We scanned each animal by using the C-arm CT system, acquiring more than 500 images during a 20-second rotation through more than 200 degrees . Multiplanar reformatted images with isotropic resolution were reconstructed on the workstation by using product truncation, scatter, beam-hardening, and ring-artifact correction algorithms. The brains were harvested and sliced for hematoma measurement and compared with imaging findings.Five intracranial hematomas were created in group 1 animals, and all were visualized. Six were created in group 2, and 3 were visualized. One nonvisualized hematoma was not confirmed at necropsy. All the others in both groups were confirmed. In group 1 (with contrast), small hematomas were detectable even when the hematocrit was 19%-20%. In group 2 (without contrast) C-arm CT was able to detect small hematomas (<1.0 cm(2)) created with hematocrits of 29%-37%. The area of hematoma measured from the C-arm CT data was, on average, within 15% of the area measured from harvested brain.The image quality obtained with this implementation of C-arm CT was sufficient to detect experimentally created small intracranial hematomas. This capability should provide earlier detection of hemorrhagic complications that may occur during neurointerventional procedures.

    View details for DOI 10.3174/ajnr.A0898

    View details for Web of Science ID 000255129700029

    View details for PubMedID 18202240

  • Neurologic complications of arteriovenous malformation embolization using liquid embolic agents AMERICAN JOURNAL OF NEURORADIOLOGY Jayaraman, M. V., Marcellus, M. L., Hamilton, S., Do, H. M., Campbell, D., Chang, S. D., Steinberg, G. K., Marks, M. P. 2008; 29 (2): 242-246

    Abstract

    Embolization of arteriovenous malformations (AVMs) is commonly used to achieve nidal volume reduction before microsurgical resection or stereotactic radiosurgery. The purpose of this study was to examine the overall neurologic complication rate in patients undergoing AVM embolization and analyze the factors that may determine increased risk.We performed a retrospective review of all patients with brain AVMs embolized at 1 center from 1995 through 2005. Demographics, including age, sex, presenting symptoms, and clinical condition, were recorded. Angiographic factors including maximal nidal size, presence of deep venous drainage, and involvement of eloquent cortex were also recorded. For each embolization session, the agent used, number of pedicles embolized, the percentage of nidal obliteration, and any complications were recorded. Complications were classified as the following: none, non-neurologic (mild), transient neurologic deficit, and permanent nondisabling and permanent disabling deficits. The permanent complications were also classified as ischemic or hemorrhagic. Modified Rankin Scale (mRS) scores were collected pre- and postembolization on all patients. Univariate regression analysis of factors associated with the development of any neurologic complication was performed.Four hundred eighty-nine embolization procedures were performed in 192 patients. There were 6 Spetzler-Martin grade I (3.1%), 26 grade II (13.5%), 71 grade III (37.0%), 57 grade IV (29.7%), and 32 grade V (16.7%) AVMs. Permanent nondisabling complications occurred in 5 patients (2.6%) and permanent disabling complications or deaths occurred in 3 (1.6%). In addition, there were non-neurologic complications in 4 patients (2.1%) and transient neurologic deficits in 22 (11.5%). Five of the 8 permanent complications (2.6% overall) were ischemic, and 3 of 8 (1.6% overall) were hemorrhagic. Of the 178 patients who were mRS 0-2 pre-embolization, 4 (2.3%) were dependent or dead (mRS >2) at follow-up. Univariate analysis of risk factors for permanent neurologic deficits following embolization showed that basal ganglia location was weakly associated with a new postembolization neurologic deficit.Embolization of brain AVMs can be performed with a high degree of technical success and a low rate of permanent neurologic complications.

    View details for DOI 10.3174/ajnr.A0793

    View details for Web of Science ID 000253345200013

    View details for PubMedID 17974613

  • Wherefore wingspan? AMERICAN JOURNAL OF NEURORADIOLOGY Kallmes, D. F., Do, H. M. 2007; 28 (6): 997-998

    View details for Web of Science ID 000247395800001

    View details for PubMedID 17569943

  • Endovascular embolization of the swine rete mirabile with Eudragit-E 100 polymer AMERICAN JOURNAL OF NEURORADIOLOGY Arakawa, H., Murayama, Y., DAVIS, C. R., Howard, D. L., Baumgardner, W. L., Marks, M. P., Do, H. M. 2007; 28 (6): 1191-1196

    Abstract

    Both adhesive and nonabrasive embolic agents are available for arteriovenous malformation (AVM) embolization. The purpose of this study was to evaluate a novel ethanol-based nonadhesive liquid embolic material in a swine AVM model.Eudragit (copolymer of methyl and butyl methacrylate and dimethylaminoethyl methacrylate) was dissolved in 50% ethanol and 50% iopamidol. Eudragit was injected into 9 retia mirabilia (RMs). Ethanol and iopamidol mixture were injected into 4 RMs for comparison. Three RMs embolized with Eudragit mixture were evaluated both angiographically and histopathologically acutely (3-24 hours) and at 30 days and 90 days after embolization.No procedural complications from Eudragrit embolization were noted, including retention or adhesion of the microcatheter. Various degrees of inflammation were observed in the acute and 30-day specimens. Two RMs showed partial recanalization on both histopathology and follow-up angiography in the 30-day group. Arterial fibrosis and calcification were observed in the 30- and 90-day specimens. The internal elastic lamina was disrupted in the 30- and 90-day specimens, but there was no evidence of Eudragit extravasation or hemorrhage. Endothelial damage was seen in all specimens and was particularly severe in the 30- and 90-day specimens.Eudragit polymer induced inflammation in thrombosis similar to n-butyl 2-cyanoacrylate, but without the disadvantages of perivascular hemorrhage and extravasation of embolization material. Although recanalization of some embolized RMs was noted, further investigation into Eudragit as a potentially useful embolic material for brain AVMs is warranted.

    View details for DOI 10.3174/ajnr.A0536

    View details for Web of Science ID 000247395800044

    View details for PubMedID 17569986

  • Surgical and endovascular management of symptomatic posterior circulation fusiform aneurysms JOURNAL OF NEUROSURGERY Coert, B. A., Chang, S. D., Do, H. M., Marks, M. P., Steinberg, G. K. 2007; 106 (5): 855-865

    Abstract

    Patients with fusiform aneurysms can present with subarachnoid hemorrhage (SAH), mass effect, ischemia, or unrelated symptoms. The absence of an aneurysm neck impedes the direct application of a clip and endovascular coil deployment. To evaluate the effects of their treatments, the authors retrospectively analyzed a consecutive series of patients with posterior circulation fusiform aneurysms treated at Stanford University Medical Center between 1991 and 2005.Forty-nine patients (mean age 53 years, male/female ratio 1.2:1) treated at the authors' medical center form the basis of the analysis. Twenty-nine patients presented with an SAH. The patients presenting without SAH had cranial nerve dysfunction (five patients), symptoms of mass effect (eight patients), ischemia (six patients), or unrelated symptoms (one patient). The aneurysms were located on the vertebral artery (VA) or posterior inferior cerebellar artery (PICA) (21 patients); vertebrobasilar junction (VBJ) or basilar artery (BA) (18 patients); and posterior cerebral artery (PCA) (10 patients). Pretreatment clinical grades were determined using the Hunt and Hess scale; for patients with unruptured aneurysms (Hunt and Hess Grade 0) functional subgrades were added. Outcome was evaluated using the Glasgow Outcome Scale (GOS) score during a mean follow-up period of 33 months. Overall long-term outcome was good (GOS Score 4 or 5) in 59%, poor (GOS Score 2 or 3) in 16%, and fatal (GOS Score 1) in 24% of the patients. In a univariate analysis, poor outcome was predicted by age greater than 55 years, VBJ location, pretreatment Hunt and Hess grade in patients presenting with SAH, and incomplete aneurysm thrombosis after endovascular treatment. In a multivariate analysis, age greater than 55 years was the confounding factor predicting poor outcome. Stratification by aneurysm location removed the effect of age. Of 13 patients with residual aneurysm after treatment, five (38%) subsequently died of SAH (three patients) or progressive mass effect/brainstem ischemia (two patients).Certain posterior circulation aneurysm locations (PCA, VA-PICA, and BA-VBJ) represent separate disease entities affecting patients at different ages with distinct patterns of presentation, treatment options, and outcomes. Favorable overall long-term outcome can be achieved in 90% of patients with PCA aneurysms, in 60% of those with VA-PICA aneurysms, and in 39% of those with BA-VBJ aneurysms when using endovascular and surgical techniques. The natural history of the disease was poor in patients with incomplete aneurysm thrombosis after treatment.

    View details for Web of Science ID 000246047800008

    View details for PubMedID 17542530

  • Dissection of the V4 segment of the vertebral artery: clinicoradiologic manifestations and endovascular treatment EUROPEAN RADIOLOGY Yoon, W., Seo, J. J., Kim, T. S., Do, H. M., Jayaraman, M. V., Marks, M. P. 2007; 17 (4): 983-993

    Abstract

    Intracranial vertebral artery (VA) dissection has three clinical presentations: ischemia, hemorrhage, and mass effect. Imaging findings of intracranial VA dissections vary according to clinical presentation. Irregular stenosis or occlusion of the VA is the most common finding in patients with posterior fossa infarction, whereas a dissecting aneurysm is the main feature in those with acute subarachnoid hemorrhage. A chronic, giant, dissecting aneurysm can cause mass effect on the brain stem or cranial nerves, as well as distal embolism. Magnetic resonance imaging is useful for detection of intramural hematomas and intimal flaps, both of which are diagnostic of VA dissection. Multidetector computed tomography angiography is increasingly used for diagnosis of VA dissection. Catheter angiography is still beneficial for evaluation of precise endoluminal morphology of the dissection before surgical or endovascular intervention. Endovascular treatment is now considered a major therapeutic option for patients with a ruptured dissecting aneurysm or a chronic dissecting aneurysm. Anticoagulation therapy is currently considered the initial treatment of choice in patients with posterior circulation ischemic symptoms. Endovascular treatment, such as stent-assisted angioplasty or coil occlusion at the dissection site, can be performed in selected patients with posterior fossa ischemic symptoms.

    View details for DOI 10.1007/s00330-006-0272-8

    View details for Web of Science ID 000244753900014

    View details for PubMedID 16670864

  • Morphologic assessment of middle cerebral artery aneurysms for endovascular treatment. Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association Jayaraman, M. V., Do, H. M., Versnick, E. J., Steinberg, G. K., Marks, M. P. 2007; 16 (2): 52-56

    Abstract

    Aneurysms of the middle cerebral artery (MCA) trifurcation region are underrepresented in large series of endovascularly treated aneurysms. The purpose of our study was to evaluate the incidence of specific morphologic features of MCA bifurcation aneurysms that may affect suitability for endovascular treatment.We evaluated 53 consecutive patients with 58 bifurcation or trifurcation MCA aneurysms seen for angiographic evaluation during a 4-year period at our institution. All angiograms were reviewed for: aneurysm size (largest dimension, dome and neck size), branch vessels originating from the aneurysm sac, straightening of the aneurysm wall to suggest intramural thrombus, calcification in the region of the aneurysm, stenosis of the parent vessel, and presence of daughter sacs.Of 58 aneurysms, 51 (88%) had a dome to neck ratio less than 2:1. Branch vessel incorporation in the aneurysm sac was seen in 23/58 (40%), straightening suggestive of thrombus in 14/58 (24%), calcification in 2/58 (3%), parent vessel stenosis in 1/58 (2%), and daughter sacs in 4/58 (7%).The majority of MCA aneurysms have morphologic features such as a dome to neck ratio less than 2:1 or branch vessel incorporation that may make them unsuitable for endovascular treatment using conventional intra-aneurysmal coiling.

    View details for PubMedID 17689394

  • Hemorrhage rate in patients with Spetzler-Martin grades IV and V arteriovenous malformations - Is treatment justified? STROKE Jayaraman, M. V., Marcellus, M. L., Do, H. M., Chang, S. D., Rosenberg, J. K., Steinberg, G. K., Marks, M. P. 2007; 38 (2): 325-329

    Abstract

    We sought to examine the prospective annual risk of hemorrhage in patients harboring Spetzler-Martin grades IV and V arteriovenous malformations (AVMs) before and after initiation of treatment.Medical records of 61 consecutive patients presenting with Spetzler-Martin grades IV and V AVMs were retrospectively reviewed for demographics, angiographic features, presenting symptom(s), and time of all hemorrhage events, before or after treatment initiation. Pretreatment hemorrhage rates (excluding hemorrhages at presentation) and posttreatment rates were subsequently calculated. Modified Rankin Scale (mRS) scores before and after treatment were recorded.The annual pretreatment hemorrhage rate for all patients was 10.4% per year (95% CI, 2.2 to 15.4%), 13.9% (95% CI, 3.5 to 22.1%) in patients with hemorrhagic presentation and 7.3% (2.6 to 14.3%) in patients with nonhemorrhagic presentation. Posttreatment hemorrhage rates were 6.1% per year (95% CI, 2.5 to 13.2%) for all patients, 5.6% (95% CI, 2.1 to 11.8%) for patients presenting with hemorrhage and 6.4% (95% CI, 1.6 to 10.1%) in patients with nonhemorrhagic presentation. A noninferiority test showed that the posttreatment hemorrhage rate was less than or equal to the pretreatment hemorrhage rate (P<0.0001), with some indication that the reduction was greatest in patients with hemorrhagic presentation. Of the 62 patients, 51 (82%) had an mRS score of 0 to 2 before treatment, and 47 (76%) had an mRS score of 0 to 2 at the last follow-up after treatment.The annual rate of hemorrhage in grades IV and V AVMs is higher in this series than reported for all AVMs, which may reflect some referral bias in this single-center study. Nevertheless, initiation of treatment does not appear to increase the rate of subsequent hemorrhage. Treatment for these lesions may be warranted, given their poor natural history.

    View details for DOI 10.1161/01.STR.0000254497.24545.de

    View details for Web of Science ID 000244122600036

    View details for PubMedID 17194881

  • Treatment of traumatic cervical arteriovenous fistulas with N-butyl-2-cyanoacrylate AMERICAN JOURNAL OF NEURORADIOLOGY Jayaraman, M. V., Do, H. M., Marks, M. P. 2007; 28 (2): 352-354

    Abstract

    We report 2 cases of traumatic arteriovenous fistulas in the neck treated with transarterial embolization with n-butyl-2-cyanoacrylate (n-BCA). In both cases, covered stent placement across the fistula to preserve the artery was not possible. Detachable coil placement was attempted in one case but was not successful. Both fistulas were successfully treated with n-BCA embolization. To our knowledge, these are the first 2 such cases reported of high-flow cervical arteriovenous fistulas treated with n-BCA embolization.

    View details for Web of Science ID 000244263200038

    View details for PubMedID 17297011

  • Carotid and vertebral rete mirabile in man presenting with intraparenchymal hemorrhage: a case report. Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association Li, G., Jayaraman, M. V., Lad, S. P., Adler, J., Do, H., Steinberg, G. K. 2006; 15 (5): 228-231

    Abstract

    Carotid and vertebral rete mirabile is an unusual segmental regression of both the cavernous carotid artery and transdural vertebral arteries with a network of collateral vessels seen rarely in human beings. We present a 57-year-old woman with carotid and vertebral rete mirabile who presented with an acute intraparenchymal hemorrhage. The majority of patients present with subarachnoid hemorrhage or ischemic stroke. This is the first case of a non-Asian patient presenting with an intraparenchymal hemorrhage. In this case report, we describe the clinical and angiographic features of this unusual entity.

    View details for PubMedID 17904080

  • Angioplasty for symptomatic intracranial stenosis - Clinical outcome STROKE Marks, M. P., Wojak, J. C., Al-Ali, F., Jayaraman, M., Marcellus, M. L., Connors, J. J., Do, H. M. 2006; 37 (4): 1016-1020

    Abstract

    Medical treatment of symptomatic intracranial stenosis carries a high risk of stroke. This study was done to evaluate the clinical and angiographic outcomes after intracranial angioplasty for this disease.A total of 120 patients with 124 intracranial stenoses were treated by primary angioplasty. All patients had neurologic symptoms (stroke or transient ischemic attack) attributable to intracranial stenoses > or =50%. Angiograms were evaluated before and after angioplasty for the degree of stenosis.Pretreatment stenoses varied from 50% to 95% (mean 82.2+/-10.2). Post-treatment stenoses varied from 0% to 90% (mean 36.0+/-20.1). There were 3 strokes and 4 deaths (all neurological) within 30 days of the procedure, giving a combined periprocedural stroke and death rate of 5.8%. A total of 116 patients (96.7%) were available for a mean follow-up time of 42.3 months. There were 6 patients who had a stroke in the territory of treatment and 5 additional patients with stroke in other territories. Ten deaths occurred during the follow-up period, none of which were neurological. Including the periprocedural stroke and deaths, this yielded an annual stroke rate of 3.2% in the territory of treatment and a 4.4% annual rate for all strokes.Intracranial angioplasty can be performed with a high degree of technical success and a low risk of complications. Long-term clinical follow-up of intracranial angioplasty patients demonstrates a risk of future strokes that compares favorably to patients receiving medical therapy.

    View details for DOI 10.1161/01.STR.0000206142.03677.c2

    View details for Web of Science ID 000236292100022

    View details for PubMedID 16497979

  • Progression of unilateral Moyamoya disease: A clinical series CEREBROVASCULAR DISEASES Kelly, M. E., Bell-Stephens, T. E., Marks, M. P., Do, H. M., Steinberg, G. K. 2006; 22 (2-3): 109-115

    Abstract

    The natural history of unilateral moyamoya disease (MMD) in adult patients is not clearly described in the literature. We present a series of 18 patients with unilateral MMD and analyze the risk factors for progression to bilateral disease.A retrospective review of 157 MMD patients treated at Stanford University Medical Center from 1991 to 2005 identified 28 patients with unilateral MMD (defined as none, equivocal or mild involvement on the contralateral side).Eighteen patients (5 males and 13 females) were identified with unilateral MMD and angiographic follow-up of > or =5 months. Mean radiologic follow-up (+/- standard error of the mean) was 19.3 +/- 3.4 months and mean clinical follow-up was 24.5 +/- 3.7 months. Five patients had childhood onset MMD and 13 patients had adult onset disease. Angiographic progression from unilateral to bilateral disease was seen in 7 patients (38.9%) at a mean follow-up of 12.7 +/- 2.4 months. Four of the 7 patients had significant clinical and radiologic progression requiring surgical intervention. Five of 7 patients that progressed had adult onset MMD. The presence of equivocal or mild stenotic changes of the contralateral anterior cerebral artery (ACA), middle cerebral artery (MCA) or internal carotid artery (ICA) was an important predictor of progression (p < 0.01); 6 of 8 patients (75%) with equivocal or mild contralateral disease progressed, whereas only 1 of 10 patients (10.0%) with no initial contralateral disease progressed to bilateral MMD. One patient had mild or equivocal MCA, ICA and ACA stenosis at the time of initial diagnosis and this patient progressed.Contralateral progression in the adult form occurs more commonly than previously reported. The presence of minor changes in the contralateral ACA, intracranial ICA and MCA is an important predictor of increased risk of progression. Patients with a completely normal angiogram on the contralateral side have a very low risk of progression.

    View details for DOI 10.1159/000093238

    View details for Web of Science ID 000243591900005

    View details for PubMedID 16685122

  • Mechanical thrombectomy following intravenous thrombolysis in the treatment of acute stroke ARCHIVES OF NEUROLOGY Lansberg, M. G., Fields, J. D., Albers, G. W., Jayaraman, M. V., Do, H. M., Marks, M. P. 2005; 62 (11): 1763-1765

    Abstract

    The efficacy of intravenous thrombolytics in acute stroke is limited by low rates of recanalization of occluded arteries. Treatment with intravenous thrombolytics followed by mechanical thrombectomy is a novel approach that may increase recanalization rates without compromising time to initiation of treatment.To report our experience with 2 patients who received this combination therapy and outline plans for a prospective pilot study.Case studies at a university hospital.Patients treated with intravenous thrombolytics within 3 hours of symptom onset subsequently underwent computed tomographic angiography. If an occlusion of a proximal cerebral vessel was shown by a computed tomographic angiogram, mechanical thrombectomy was performed. Patients were observed for 1 month after treatment.National Institutes of Health Stroke Scale (NIHSS) score.The computed tomographic angiography of 2 patients showed complete occlusion of the M1 branch of the middle cerebral artery following administration of intravenous thrombolytics. The NIHSS scores were 21 and 13. In both cases, blood flow through the occluded artery was restored with mechanical thrombectomy and dramatic neurologic improvement occurred. There were no complications. The NIHSS scores were 0 and 2 at 1-month follow-up.Treatment with intravenous thrombolytics followed by mechanical thrombectomy may improve outcomes in acute stroke patients and a pilot safety trial is warranted.

    View details for Web of Science ID 000233250900017

    View details for PubMedID 16286552

  • Visual field preservation after curative multi-modality treatment of occipital lobe artemovenous malformations NEUROSURGERY Sinclair, J., Marks, M. P., Levy, R. P., Adler, J. R., Chang, S. D., Lopez, J. R., Do, H. M., Bell-Stephens, T. E., Lim, M., Steinberg, G. K. 2005; 57 (4): 655-666

    Abstract

    Occipital lobe arteriovenous malformations (AVMs) provide challenging management decisions because of their proximity to the visual cortex and optic radiations. Preservation of visual function throughout treatment is the mainstay of therapeutic planning. We reviewed visual field (VF) outcomes of all patients who received curative treatment for occipital AVMs at Stanford University to evaluate the efficacy of different treatment strategies.We conducted a retrospective review of 55 patients with occipital AVMs treated at Stanford University between 1984 and 2003. Clinical presentation, AVM morphology, and treatment modality were correlated with VF function before and after therapeutic intervention.Of 55 patients, 48 (87.3%) underwent multimodality AVM treatment (7 patients < 3 yr from radiosurgery were excluded from final analysis). One patient died from intracerebral hemorrhage 11 months post-radiosurgery, and five patients deferred further treatment. Forty-two patients (87.5%) were cured, with no residual AVM on final angiography. Curative therapeutic modalities used included embolization alone (2 patients), microsurgery alone (6 patients), microsurgery with radiosurgery (1 patient), microsurgery with embolization (23 patients), radiosurgery with embolization (4 patients), and embolization with radiosurgery and microsurgery (6 patients). Mean follow-up was 5.8 years including treatment. VF follow-up was available in all 42 patients. Twenty-eight (66.7%) patients experienced no change in VFs, six (14.3%) patients with previously abnormal VFs improved, and eight (19.0%) patients showed worsening of VFs (although none developed a new homonymous VF deficit). Duration of treatment was related to VF outcome in patients who presented without a history of AVM-related hemorrhage.Occipital AVMs can be safely cured using multimodality strategies with minimal risk to visual function despite the proximity of these lesions to the visual cortex and associated pathways.

    View details for DOI 10.1227/01.NEU.0000175547.05291.85

    View details for Web of Science ID 000236681500018

    View details for PubMedID 16239877

  • Truly hybrid x-ray/MR imaging: Toward a streamlined clinical system ACADEMIC RADIOLOGY Ganguly, A., Wen, Z. F., Daniel, B. L., Butts, K., Kee, S. T., Rieke, V., Do, H. M., Pelc, N. J., Alley, M. T., Fahrig, R. 2005; 12 (9): 1167-1177

    Abstract

    We have installed an improved X-ray/MR (XMR) truly hybrid system with higher imaging signal-to-noise ratio (SNR) and versatility than our first prototype. In our XMR design, a fixed anode X-ray fluoroscopy system is positioned between the two donut-shaped magnetic poles of a 0.5T GE Signa-SP magnet (SP-XMR). This paper describes the methods for increased compatibility between the upgraded x-ray and MR systems that have helped improve patient management.A GE OEC 9800 system (GE OEC Salt Lake City, UT) was specially reconfigured for permitting X-ray fluoroscopy inside the interventional magnet. A higher power X-ray tube, a new permanent tube mounting system, automatic exposure control (AEC), remote controlled collimators, choice of multiple frame rates, DICOM image compatibility, magnetically shimmed X-ray detector, X-ray compatible MR coil, and better RF shielding are the highlights of the new system. A total of 23 clinical procedures have been conducted with SP-XMR guidance of which five were performed using the new system.The 70% increased power for fluoroscopy, and a new 6 times higher power single frame imaging mode, has improved imaging capability. The choice of multiple imaging frame rates, AEC, and collimator control allow reduction in X-ray exposure to the patient. The DICOM formatting has permitted easy transfer of clinical images over the hospital PACS network. The increased MR compatibility of the detector and the X-ray transparent MR coil has enabled faster switching between X-ray and MR imaging modes.The improvements introduced in our SP-XMR system have further streamlined X-ray/MR hybrid imaging. Additional clinical procedures could benefit from the new SP-XMR imaging.

    View details for DOI 10.1016/j.acra.2005.03.076

    View details for Web of Science ID 000231463500014

    View details for PubMedID 16099685

  • Prospective analysis of clinical outcomes after percutaneous vertebroplasty for painful osteoporotic vertebral body fractures AMERICAN JOURNAL OF NEURORADIOLOGY Do, H. M., Kim, B. S., Marcellus, M. L., CURTIS, L., Marks, M. P. 2005; 26 (7): 1623-1628

    Abstract

    Previous studies have retrospectively reported the positive effects of percutaneous vertebroplasty. The purpose of our study was to evaluate prospectively the effects of vertebroplasty on mobility, analgesic use, pain, and SF-36 (short-form 36-item) scales for patients with painful vertebral compression fractures that are refractory to medical therapy.We prospectively followed 167 patients who received 207 vertebroplasty treatment sessions for stabilization of 264 symptomatic vertebral compression fractures between August 1999 and January 2003. The average age of patients was 74.6 years (SD = 12.2 years), and 76% were women. Pre- and postprocedural measurements of pain, mobility, analgesic use, and SF-36 scales were compared at 1 month after the procedure and between 6 months and 3 years after the procedure with the SF-36 scales.Respective pre- and post-treatment pain scores were 8.71 (SE = 0.1) and 2.77 (SE = 0.18; P < .00001). Respective pre- and post-treatment analgesic use scores were 2.93 (SE = 0.9) and 1.64 (SE = 0.09; P < .00001). Respective pre- and post-treatment activity levels were 2.66 (SE = 0.1) and 1.64 (SE = 0.11; P < .00001). There was a statistically significant improvement on nine of 10 SF-36 scales (P < .001) after 1 month and on eight of 10 SF-36 scales (P < .02) at long-term follow-up.Percutaneous vertebroplasty offers statistically significant benefits in decreasing pain, decreasing use of analgesics, and increasing mobility in appropriately selected patients. Percutaneous vertebroplasty also offers a statistically significant benefit in most SF-36 scales at both short- and long-term follow-up.

    View details for Web of Science ID 000231182800004

    View details for PubMedID 16091504

  • Mechanical thrombectomy for acute stroke AMERICAN JOURNAL OF NEURORADIOLOGY Versnick, E. J., Do, H. M., Albers, G. W., Tong, D. C., Marks, M. P. 2005; 26 (4): 875-879

    Abstract

    We evaluated a mechanical thrombectomy protocol to treat acute stroke and report the angiographic results and clinical outcomes.Patients with anterior circulation strokes <8 hours and posterior circulation strokes <12 hours were treated at a single center over 10 months. Patients were excluded if they were candidates for intravenous tissue plasminogen activator (tPA). Treatment involved one of two mechanical thrombectomy devices. Retrieval was augmented by low-dose intra-arterial tPA if needed. Outcome was measured by using the Modified Rankin score.Ten patients were treated: five with anterior circulation strokes, four with posterior circulation strokes, and one with embolic strokes involving both circulations. Mean National Institutes of Health Stroke Scale score at presentation was 24.6 +/- 10.9. In eight patients (80%), revascularization was successful (Thrombolysis in Acute Myocardial Infarction score, 3). Mean time from symptom onset to initiation of the procedure was 6 hours (5.3 hours for anterior circulation and 7.0 hours for posterior circulation). Mean time for recanalization from the start of the procedure was 1.17 +/- 0.58 hours for the six anterior circulation strokes and 2.75 +/- 1.34 hours in the two posterior circulation strokes. Five patients died within 48 hours; all had posterior circulation strokes. Mean Modified Rankin score at 90 days was 1.4.In this small series, mechanical thrombectomy of acute stroke appeared to improve recanalization rates compared with intra-arterial thrombolysis. No hemorrhagic complications occurred. Further study is required to determine the role of these techniques.

    View details for Web of Science ID 000228273400036

    View details for PubMedID 15814937

  • Intracranial Angioplasty without stenting for symptomatic atherosclerotic stenosis: Long-term follow-up AMERICAN JOURNAL OF NEURORADIOLOGY Marks, M. P., Marcellus, M. L., Do, H. M., Schraedley-Desmond, P. K., Steinberg, G. K., Tong, D. C., Albers, G. W. 2005; 26 (3): 525-530

    Abstract

    Angioplasty and stent placement have been reported for the treatment of intracranial stenosis. This study was undertaken to assess the efficacy and long-term clinical outcome of angioplasty without stent placement for patients with symptomatic intracranial stenosis.A retrospective study was done to evaluate 36 patients with 37 symptomatic atherosclerotic intracranial stenosis who underwent primary balloon angioplasty. All patients had symptoms despite medical therapy. Thirty-four patients were available for follow-up ranging from 6 to 128 months. Mean follow-up was 52.9 months.Mean pretreatment stenosis was 84.2% before angioplasty and 43.3% after angioplasty. The periprocedural death and stroke rate was 8.3% (two deaths and one minor stroke). Two patients had strokes in the territory of angioplasty at 2 and 37 months after angioplasty. The annual stroke rate in the territory appropriate to the site of angioplasty was 3.36%, and for those patients with a residual stenosis of > or =50% it was 4.5%. Patients with iatrogenic dissection (n=11) did not have transient ischemic attacks or strokes after treatment.Results of long-term follow-up suggest that intracranial angioplasty without stent placement reduces the risk of further stroke in symptomatic patients.

    View details for Web of Science ID 000227628500016

    View details for PubMedID 15760860

  • Alteration in the venous drainage of a dural arteriovenous fistula following angioplasty AMERICAN JOURNAL OF NEURORADIOLOGY Gutierrez, A., Do, H. M., Marks, M. P. 2004; 25 (6): 1086-1088

    Abstract

    The pattern of venous drainage from a dural arteriovenous fistula (DAVF) has been shown to affect the natural history of these lesions. Angioplasty and stent placement of the dural sinuses have been described to improve outflow in venous hypertensive states and may improve the venous drainage pattern from a DAVF. We report the case of a patient with a benign but stenosed type IIa transverse sinus DAVF who underwent angioplasty to improve venous outflow. This resulted in conversion of the DAVF to a more malignant type IIb drainage pattern with reflux into the cortical venous system.

    View details for Web of Science ID 000222067600035

    View details for PubMedID 15205154

  • N-butyl cyanoacrylate glue embolization of splenic artery aneurysms JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Kim, B. S., Do, H. M., Razavi, M. 2004; 15 (1): 91-94

    Abstract

    A patient with Polyarteritis Nodosa presented with abdominal pain and low hematocrit level. Abdominal computed tomography (CT) depicted the presence of free blood and CT angiography revealed two aneurysms in the inferior branch of the splenic artery that were subsequently treated by endovascular transarterial embolization with N-Butyl Cyanoacrylate. Post embolization splenic arteriography demonstrated complete embolization of both aneurysms, including the inflow and outflow vessels.

    View details for DOI 10.1097/01.RVI.0000099537.29957.13

    View details for Web of Science ID 000228600100012

    View details for PubMedID 14709694

  • Neurophysiological monitoring in the endovascular therapy of aneurysms AMERICAN JOURNAL OF NEURORADIOLOGY Liu, A. Y., Lopez, J. R., Do, H. M., Steinberg, G. K., Cockroft, K., Marks, M. P. 2003; 24 (8): 1520-1527

    Abstract

    Endovascular aneurysm therapy has associated risks of ischemic complications. We undertook this study to evaluate the efficacy of neurophysiological monitoring (NPM) techniques in the detection of ischemic changes that may be seen during endovascular treatment of cerebral aneurysms.Thirty-five patients underwent NPM during endovascular treatment of cerebral aneurysms. The patients underwent a total of 50 endovascular procedures, including balloon test occlusion (19 patients), GDC embolization (22 patients), and permanent vessel occlusion (nine patients). NPM included electroencephalography, somatosensory evoked potentials, and/or brain stem auditory evoked potentials, depending on the location of the aneurysm.NPM changes were seen in nine (26%) of 35 patients and altered the management in five (14%) of 35 patients. In three of the five cases, NPM changes were observed without corresponding neurologic physical examination changes after balloon test occlusion (performed while the patients were under general anesthesia in two cases). In the two other cases in which NPM changes altered management, ischemia was detected at the time of intra-aneurysmal therapy while the patients were under general anesthesia. Overall, 18 of 35 patients underwent a total of 19 balloon test occlusion procedures. Of the 17 remaining patients, 13 underwent aneurysm coiling, two were not treated because of inability to safely place coils, and two were treated for distal aneurysms. Two patients developed transient neurologic deficits without concurrent NPM changes, representing false-negative NPM test results.NPM is a valuable adjunct to endovascular treatment of cerebral aneurysms. Our study suggests that these monitoring techniques may reduce ischemic complications and can be used to help guide therapeutic decisions.

    View details for Web of Science ID 000185400100007

    View details for PubMedID 13679263

  • Multimodality treatment of giant intracranial arteriovenous malformations NEUROSURGERY Chang, S. D., Marcellus, M. L., Marks, M. P., Levy, R. P., Do, H. M., Steinberg, G. K. 2003; 53 (1): 1-11

    Abstract

    Giant arteriovenous malformations (AVMs) (i.e., those greater than 6 cm at maximum diameter) are difficult to treat and often carry higher treatment morbidity and mortality rates than do smaller AVMs. In this study, we reviewed the treatment, angiographic results, and clinical outcomes in 53 patients with giant AVMs who were treated at Stanford between 1987 and 2001.The patients selected included 20 males (38%) and 33 females (62%). Their presenting symptoms were hemorrhage (n = 20; 38%), seizures (n = 18; 34%), headaches (n = 8; 15%), and progressive neurological deficits (n = 7; 13%). One patient was in Spetzler-Martin Grade III, 9 were in Spetzler-Martin Grade IV, and 43 were in Spetzler-Martin Grade V. The mean AVM size was 6.8 cm (range, 6-15 cm). AVM venous drainage was superficial (n = 7), deep (n = 20), or both (n = 26). At presentation, 31 patients (58%) were graded in excellent neurological condition, 17 were graded good (32%), and 5 were graded poor (9%).The patients were treated with surgery (n = 27; 51%), embolization (n = 52; 98%), and/or radiosurgery (n = 47; 89%). Most patients received multimodality treatment with embolization followed by surgery (n = 5), embolization followed by radiosurgery (n = 23), or embolization, radiosurgery, and surgery (n = 23). Nineteen patients (36%) were completely cured of their giant AVMs, 90% obliteration was achieved in 4 patients (8%), less than 90% obliteration was achieved in 29 patients (55%) who had residual AVMs even after multimodality therapy, and 1 patient was lost to follow-up. Of the 33 patients who either completed treatment or were alive more than 3 years after undergoing their most recent radiosurgery, 19 patients (58%) were cured of their AVMs. The long-term treatment-related morbidity rate was 15%. The clinical results after mean follow-up of 37 months were 27 excellent (51%), 15 good (28%), 3 poor (6%), and 8 dead (15%).The results in this series of patients with giant AVMs, which represents the largest series reported to date, suggest that selected symptomatic patients with giant AVMs can be treated successfully with good outcomes and acceptable risk. Multimodality treatment is usually necessary to achieve AVM obliteration.

    View details for Web of Science ID 000183988600001

    View details for PubMedID 12823868

  • Simplicity of randomized, controlled trials of percutaneous vertebroplasty. Pain physician Hirsch, J. A., Do, H. M., Kallmes, D., Ruedy, R. M., Jarvik, J. G. 2003; 6 (3): 342-343

    View details for PubMedID 16880881

  • Percutaneous vertebroplasty: rationale, clinical outcomes, and future directions NEUROIMAGING CLINICS OF NORTH AMERICA Do, H. M. 2003; 13 (2): 343-?

    Abstract

    Percutaneous transpediculate vertebroplasty is an innovative and successful treatment of painful osteoporotic and pathologic compression fractures that are refractory to medical therapy. Large-scale clinical series have shown that vertebroplasty can provide significant pain relief with very low complication rates. Expectations of positive results of the ongoing randomized trials are high. With the accumulation of scientific data, technological advancements, and acceptance by the general community, vertebroplasty may be become the standard of care for treatment of painful vertebral body compression fractures.

    View details for DOI 10.1016/S1052-5149(03)00029-7

    View details for Web of Science ID 000183789100017

    View details for PubMedID 13677812

  • Parent vessel occlusion for vertebrobasilar fusiform and dissecting aneurysms AMERICAN JOURNAL OF NEURORADIOLOGY Leibowitz, R., Do, H. M., Marcellus, M. L., Chang, S. D., Steinberg, G. K., Marks, M. P. 2003; 24 (5): 902-907

    Abstract

    Previous reports of outcome with permanent vessel occlusion (PVO) for large, giant, or fusiform aneurysms in the posterior circulation have been limited. We undertook this study to evaluate the perioperative (within 30 days) and follow-up outcomes for patients treated with permanent occlusion of the vertebral artery for vertebrobasilar fusiform and dissecting aneurysms.Thirteen consecutive patients were studied. Two groups were defined for the study. Group I patients underwent PVO to achieve complete thrombosis of the aneurysm. Group II patients underwent PVO to reduce flow to the aneurysm where complete thrombosis was not desirable. Modified Rankin scores were obtained at presentation and at follow-up (follow-up range, 1-76 months; mean, 22.0 months).All group I aneurysms were shown to be thrombosed on the angiograms obtained at the immediate follow-up examinations. Improvement in outcome scores was achieved by all group I patients. Improvement in Rankin scores after endovascular treatment was statistically significant (P =.026). All group II patients had complete occlusion of the vertebral artery; however, continued filling of the fusiform aneurysm was still observed. Four patients in group II died during the follow-up period. Two of these deaths were attributable to the aneurysms. Of the remaining three patients, two experienced clinical worsening and one remained stable.In this series, PVO for chronic fusiform and acute dissecting aneurysms of the vertebrobasilar system proved to be a useful therapeutic endovascular technique. Long-term outcomes suggest that patients with aneurysms involving only one vertebral artery, where complete thrombosis can be achieved, have better clinical outcomes than those who have aneurysms involving the basilar artery or both vertebral arteries, where complete thrombosis cannot achieved by using PVO.

    View details for Web of Science ID 000183021100024

    View details for PubMedID 12748092

  • Aneurysmal subarachnoid hemorrhage in patient's with Hunt and Hess grade 4 or 5: Treatment using the Guglielmi detachable coil system AMERICAN JOURNAL OF NEURORADIOLOGY Weir, R. U., Marcellus, M. L., Do, H. M., Steinberg, G. K., Marks, M. P. 2003; 24 (4): 585-590

    Abstract

    Patients in poor clinical condition (Hunt and Hess grade 4 or 5) after subarachnoid hemorrhage (SAH) have historically fared poorly and many often were excluded from aggressive treatment. Early aggressive surgical treatment of SAH can produce good-quality survival for a higher percentage of patients than previously reported. We assessed the outcome of patients with Hunt and Hess grade 4 or 5 who were treated with Guglielmi detachable coil (GDC) embolization.We retrospectively evaluated the records of 27 consecutive grade 4 and 5 patients with 29 aneurysms treated within 72 hours of SAH by using GDCs. Percentage aneurysm occlusion after embolization, perioperative complications, and symptoms of vasospasm were evaluated. Outcome was assessed with the Glasgow Outcome Scale.Sixteen patients (59%) were grade 4, and 11 (41%) were grade 5. Eighteen (67%) had one aneurysm, six (22%) had two aneurysms, and three (11%) had three aneurysms. Twenty-nine aneurysms were treated. Fourteen (48%) were completely occluded, and four (14%) were nearly completely occluded (>/=95% occlusion) at embolization. Eleven aneurysms (38%) had partial coiling (<95% occlusion). In the 27 patients, one technical (4%) and one clinical (4%) complication occurred at embolization. No rehemorrhage occurred in any patients (follow-up, 6-44 months; mean, 23 months). Twenty-five (92%) had vasospasm, and seven required endovascular treatment because of worsening clinical status. Sixteen patients (59%) died within 30 days of SAH. Eight patients (30%) had a good clinical outcome at a mean follow-up of 23 months.Patients with Hunt and Hess grade 4 or 5 after SAH can undergo successful coil embolization of the aneurysms despite their poor medical condition and a high frequency of vasospasm at the time of treatment. Morbidity and mortality rates with this disease are still high. These findings compare favorably with those published in surgical series for aggressively treated patients with Hunt and Hess grade 4 or 5.

    View details for Web of Science ID 000182422900008

    View details for PubMedID 12695185

  • Line scan diffusion imaging of the spine AMERICAN JOURNAL OF NEURORADIOLOGY Bammer, R., Herneth, A. M., Maier, S. E., Butts, K., Prokesch, R. W., Do, H. M., Atlas, S. W., Moseley, M. E. 2003; 24 (1): 5-12

    Abstract

    Recent findings suggest that diffusion-weighted imaging might be an important adjunct to the diagnostic workup of disease processes in the spine, but physiological motion and the challenging magnetic environment make it difficult to perform reliable quantitative diffusion measurements. Multi-section line scan diffusion imaging of the spine was implemented and evaluated to provide quantitative diffusion measurements of vertebral bodies and intervertebral disks.Line scan diffusion imaging of 12 healthy study participants and three patients with benign vertebral compression fractures was performed to assess the potential of line scan diffusion imaging of the spinal column. In a subgroup of six participants, multiple b-value (5-3005 s/mm(2)) images were obtained to test for multi-exponential signal decay.All images were diagnostic and of high quality. Mean diffusion values were (230 +/- 83) x 10(-6) mm(2)/s in the vertebral bodies, (1645 +/- 213) x 10(-6) mm(2)/s in the nuclei pulposi, (837 +/- 318) x 10(-6) mm(2)/s in the annuli fibrosi and ranged from 1019 x 10(-6) mm(2)/s to 1972 x 10(-6) mm(2)/s in benign compression fractures. The mean relative intra-participant variation of mean diffusivity among different vertebral segments (T10-L5) was 2.97%, whereas the relative difference in mean diffusivity among participants was 7.41% (P <.0001). The estimated measurement precision was <2%. A bi-exponential diffusion attenuation was found only in vertebral bodies.Line scan diffusion imaging is a robust and reliable method for imaging the spinal column. It does not suffer as strongly from susceptibility artifacts as does echo-planar imaging and is less susceptible to patient motion than are other multi-shot techniques. The different contributions from the water and fat fractions need to be considered in diffusion-weighted imaging of the vertebral bodies.

    View details for Web of Science ID 000180962400004

    View details for PubMedID 12533319

  • Intraosseous venography during percutaneous vertebroplasty: Is it needed? AMERICAN JOURNAL OF NEURORADIOLOGY Do, H. M. 2002; 23 (4): 508-509

    View details for Web of Science ID 000175512200004

    View details for PubMedID 11950636

  • Imaging of acute subarachnoid hemorrhage with a fluid-attenuated inversion recovery sequence in an animal model: Comparison with non-contrast-enhanced CT AMERICAN JOURNAL OF NEURORADIOLOGY Woodcock, R. J., Short, J., Do, H. M., Jensen, M. E., Kallmes, D. F. 2001; 22 (9): 1698-1703

    Abstract

    Fluid-attenuated inversion recovery (FLAIR) MR imaging sequences have been previously described in the evaluation of acute subarachnoid hemorrhage (SAH) in human subjects and have demonstrated good sensitivity. The purpose of this study was to evaluate a FLAIR sequence in an animal model of SAH and to compare the results with those obtained with non-contrast-enhanced CT.SAH was experimentally induced in 18 New Zealand rabbits by injecting autologous arterial blood into the subarachnoid space of the foramen magnum. Nine animals had high-volume (1-2 mL) injections, and nine animals had low-volume (0.2-0.5 mL) injections. Four control animals were injected with 0.5 mL of saline. The animals were imaged with a FLAIR sequence and standard CT 2-5 hours after injection. Gross pathologic evaluation of seven of the animals was performed. Four blinded readers independently evaluated the CT and FLAIR images for SAH and graded the probability of SAH on a scale of 1 to 5 (1 = no hemorrhage, 5 = definite hemorrhage).Overall, the sensitivity of FLAIR was 89%, and the sensitivity of CT was 39% (P <.01). In animals with a high volume of SAH, the sensitivity of FLAIR was 100%, and the sensitivity of CT was 56%. In animals with a low volume of SAH, the sensitivity of FLAIR was 78%, and the sensitivity of CT was 22%. The specificity of FLAIR in animals without SAH was 100%, and the specificity of CT was 100%. The average reader score for FLAIR was 3.8, and that for CT was 2.2 (P <.001). Reader scores for FLAIR were higher than those for CT in 94% (P <.01) of animals with SAH and in 25% of animals without SAH (P >.05). Seven animals underwent gross pathologic examination, and all had blood in the subarachnoid space around the brain stem.FLAIR was more sensitive than CT in the evaluation of acute SAH in this model, especially when a high volume of SAH was present. This study provides a model for further experimentation with MR imaging in the evaluation of SAH. These findings are consistent with those of current clinical literature, which show FLAIR to be an accurate MR sequence in the diagnosis of SAH.

    View details for Web of Science ID 000171752400016

    View details for PubMedID 11673164

  • Hyperperfusion syndrome with hemorrhage after angioplasty for middle cerebral artery stenosis AMERICAN JOURNAL OF NEURORADIOLOGY Liu, A. Y., Do, H. M., Albers, G. W., Lopez, J. R., Steinberg, G. K., Marks, M. P. 2001; 22 (8): 1597-1601

    Abstract

    Hyperperfusion syndrome is a well-documented complication of carotid endarterectomy, as well as internal carotid artery angioplasty and stent placement. We report a similar complication after distal intracranial (middle cerebral artery [MCA] M2 segment) angioplasty. To our knowledge, this is the first report of hyperperfusion syndrome after intracranial angioplasty of a distal MCA branch.

    View details for Web of Science ID 000171119500028

    View details for PubMedID 11559514

  • Transforming growth factor beta-coated platinum coils for endovascular treatment of aneurysms: An animal study NEUROSURGERY de Gast, A. N., Altes, T. A., Marx, W. F., Do, H. M., Helm, G. A., Kallmes, D. F. 2001; 49 (3): 690-694

    Abstract

    To test the hypothesis that coating platinum coils with transforming growth factor beta (TGFbeta) would improve the cellular proliferation within experimental aneurysms relative to uncoated coils.Elastase-induced saccular aneurysms were created in 12 New Zealand White rabbits. These aneurysms were embolized with platinum coils, either "control" (unmodified) coils or "test" (coated with TGFbeta) coils. Subjects were killed either 2 weeks (n = 3, control; n = 3, test) or 6 weeks (n = 3, control; n = 3, test) after embolization. Aneurysm tissue was embedded in plastic, sectioned, and stained with hematoxylin and eosin. The thickness of tissue covering the coils at the coil-lumen interface was measured by use of a digital microscope, and was compared between groups by use of the Student's t test (P < or = 0.05).Two-week implantation samples demonstrated mean thickness of tissue overlying TGFbeta-coated coils of 36+/-15 microm and mean thickness of overlying control coils of 3+/-5 microm, indicating significantly thicker tissue growth covering test versus control coils (P = 0.02). Six-week implantation samples demonstrated mean thickness of tissue overlying TGFbeta-coated coils of 86+/-74 microm versus mean thickness overlying control coils of 37+/-6 mu; this difference did not reach statistical significance (P = 0.30). Thickness of tissue covering TGFbeta-coated coils did not change significantly from 2 to 6 weeks (P = 0.31). Tissue thickness over control coils increased significantly between 2 and 6 weeks (P = 0.002).TGFbeta-coated platinum coils undergo earlier cellular coverage than standard platinum coils, but differences in coverage between coated and control coils are no longer present at later time points. These data suggest that improvements in intra-aneurysmal cellular proliferation resulting from coil modifications, although significant in the early postembolization phase, may dissipate over time.

    View details for Web of Science ID 000170513600036

    View details for PubMedID 11523681

  • Choroid plexus papilloma of the third ventricle: angiography, preoperative embolization, and histology NEURORADIOLOGY Do, H. M., Marx, W. F., Khanam, H., Jensen, M. E. 2001; 43 (6): 503-506

    Abstract

    We report a unique case of choroid plexus papilloma of the third ventricle in an 8-month-old girl in which preoperative embolization played a salient role in management. Initial surgery was aborted due to excessive bleeding. Cerebral angiography demonstrated enlarged posterior choroidal arteries feeding the tumor, and intense, persistent tumor staining. These vessels were effectively embolized to stasis with polyvinyl alcohol particles. The patient underwent a second craniotomy and complete resection of the tumor with minimal blood loss. Postsurgical histology showed postembolization iatrogenic intratumoral necrosis.

    View details for Web of Science ID 000169547700016

    View details for PubMedID 11465767

  • Endovascular treatment of experimental aneurysms by use of biologically modified embolic devices: Coil-mediated intraaneurysmal delivery of fibroblast tissue allografts AMERICAN JOURNAL OF NEURORADIOLOGY Marx, W. F., Cloft, H. J., Helm, G. A., Short, J. G., Do, H. M., Jensen, M. E., Kallmes, D. F. 2001; 22 (2): 323-333

    Abstract

    Our long-term goal is to improve intraaneurysmal fibrosis after aneurysm embolization, by implanting exogenous fibroblasts, using platinum coils. For the current project, we tested two hypotheses: 1) that exogenous, fluorescence-labeled rabbit fibroblast allografts remained viable and proliferated within rabbit carotid arteries, and 2) that these fibroblast allografts could be reliably implanted into experimental aneurysms by use of platinum coils.Part 1. New Zealand White rabbit synovial fibroblasts obtained from a commercial vender were labeled with a fluorescent membrane marker. The common carotid arteries of New Zealand White rabbits were surgically exposed, ligated proximally and distally, and entered with 22-g angiocatheters. Through the angiocatheter we injected either phosphate-buffered saline-containing fluorescence-labeled fibroblasts (treatment vessels) or saline only (control vessels). The wounds were closed, and the subjects were kept alive for various time points up to 2 weeks. After sacrifice, the carotid artery segments were resected, processed for frozen-section histologic examination, and evaluated using epifluorescent microscopy and hematoxylin and eosin staining. Cell viability and proliferation were determined by comparing the treatment versus control vessels. Part 2. A) Fluorescence-labeled cells were grown in culture on platinum coils, which were then exposed to systemic arterial flow in the rabbit thoracic aorta for various lengths of time up to 40 minutes. The coil segments were then examined using fluorescent microscopy and the presence and relative amount of cells remaining on the coil were documented. B) Experimental aneurysms in rabbits were embolized with control platinum coils (n = 9) and platinum coils bearing rabbit synovial fibroblasts that were grown onto the coils in culture prior to implantation (n = 9). Subjects were sacrificed 3, 7, and 14 days after coil implantation. Histologic samples were studied to assess the presence or absence of nucleated cells within and around coil winds in order to determine whether fibroblasts had been successfully implanted into aneurysms. Data were evaluated using the chi-square test for statistical significance.Part 1. Fluorescence-labeled cells were examined in the treatment carotid artery segments and results were recorded at all time intervals. The treatment vessel segments showed evidence of progressive cellular proliferation, leading to complete vessel fibrosis at 2 weeks. Conversely, control vessel segments were filled predominately with unorganized thrombus at each time interval. Part 2. A) Numerous labeled fibroblasts remained adherent to the coil despite prolonged exposure to systemic arterial flow. B) Fibroblasts were seen adjacent to or within the central lumen of coils in eight (88%) of nine aneurysms treated with cell-bearing coils. Nucleated cells were not present in any of the nine control coil subjects. This represented a statistically significant difference (P < .001).Fibroblast allografts remain viable and proliferate in the vascular space in rabbits. Furthermore, these same fibroblasts, after seeding onto platinum coils in culture, remain protected within the lumen of the coils and are retained within the coil lumen even after prolonged exposure to arterial blood flow. Coils can be used to deliver viable fibroblasts directly into experimental aneurysms successfully. These findings indicate that coil-mediated cell implantation is feasible and may be a potential method of increasing the biological activity of embolic coils.

    View details for Web of Science ID 000167049300021

    View details for PubMedID 11156778

  • Magnetic resonance imaging in the evaluation of patients for percutaneous vertebroplasty. Topics in magnetic resonance imaging Do, H. M. 2000; 11 (4): 235-244

    Abstract

    Osteoporosis and osteoporotic compression fractures of the vertebral bodies are major health problems facing women and older people of both sexes. In the last several years, percutaneous vertebroplasty has been developed as a treatment for pain caused by vertebral body compression fractures and primary or metastatic neoplasms. A large part of the success of this procedure depends on correct patient selection. As such, magnetic resonance imaging (MRI) plays a vital role in this process. In this review, the clinical evaluation of patients considered for vertebroplasty, the role of MRI in the pretreatment process, the postvertebroplasty appearance of the spine on MRI, and the future applications, such as real-time guidance with MR imaging, will be discussed.

    View details for PubMedID 11133065

  • Creation of saccular aneurysms in the rabbit: A model suitable for testing endovascular devices AMERICAN JOURNAL OF ROENTGENOLOGY Altes, T. A., Cloft, H. J., Short, J. G., DeGast, A., Do, H. M., Helm, G. A., Kallmes, D. F. 2000; 174 (2): 349-354

    Abstract

    This study developed an animal model of intracranial aneurysms suitable for evaluating emerging endovascular devices for aneurysmal therapy. We characterized the short-, medium-, and long-term attributes of this endovascular technique for saccular aneurysmal creation in the rabbit.The right common carotid artery was surgically exposed in nine New Zealand white rabbits. Using endovascular techniques, we occluded the origin of the right common carotid artery with a pliable balloon. Elastase was incubated endoluminally in the proximal common carotid artery above the balloon. The common carotid artery was ligated distally. Animals were studied angiographically and sacrificed at 2 weeks (n = 3), 10 weeks (n = 3), and 24 weeks (n = 3) after aneurysm creation. Histology was obtained.Saccular aneurysms formed in eight of the nine rabbits. The aneurysm projected from the apex of an approximately 90 degree curve of the parent vessel, the brachiocephalic artery. Mean aneurysm diameter was 4.5 mm (SD, 1.2 mm), and mean height was 7.5 mm (SD, 1.6 mm). All samples showed thinned elastic lamina and no evidence of inflammation. In four of eight aneurysms, unorganized thrombus was present in the dome of the aneurysm.Arterial aneurysms with intact endothelium and deficient elastic lamina were reliably created in an area of high shear stress in New Zealand white rabbits. Three of these aneurysms remained patent for at least 6 months. We found a simple procedure that can be readily applied to the testing of new endovascular devices for a reliable creation of aneurysms in rabbits.

    View details for Web of Science ID 000084885000013

  • Cerebral atrophy in Cushing's disease SURGICAL NEUROLOGY Simmons, N. E., Lipper, M. H., Laws, E. R. 2000; 53 (1): 72-76

    Abstract

    Cushing's disease causes significant pathological changes throughout the body as a result of elevated cortisol levels. Very few systematic investigations have focused on the morphologic effects of hypercortisolism on the central nervous system. The validity of using premature cerebral atrophy as a diagnostic tool for Cushing's disease remains unknown.This study includes 63 patients with Cushing's disease who were evaluated and treated at the University of Virginia Medical Center. Radiologists randomly compared these individuals with age- and sex-matched controls in a blinded protocol, assessing the degree of cerebral atrophy on computed tomography and magnetic resonance scans.Patients with Cushing's disease showed significant premature atrophy when compared with controls. This trend continued after subdividing the groups based on age and duration of symptoms except in the following groups: age greater than 60, duration of symptoms less than 1 year, and symptoms lasting between 4-5 years.Excluding the three aforementioned groups, the hypercortisolemic state manifested in patients with Cushing's disease promotes the premature development of cerebral atrophy, which can be identified on routine radiologic imaging and may assist in the clinical diagnosis of the condition.

    View details for Web of Science ID 000085420000029

    View details for PubMedID 10697236

  • Histologic evaluation of platinum coil embolization in an aneurysm model in rabbits RADIOLOGY Kallmes, D. F., Helm, G. A., Hudson, S. B., Altes, T. A., Do, H. M., Mandell, J. W., Cloft, H. J. 1999; 213 (1): 217-222

    Abstract

    To characterize the histologic response to platinum coil embolization by using a rabbit aneurysm model.Saccular aneurysms were created in New Zealand White rabbits by using vessel ligation with intraluminal elastase incubation. Aneurysms were subsequently embolized by using platinum coils. Subjects were sacrificed at various intervals up to 12 weeks following coil embolization. The aneurysm cavities and adjacent vessels were embedded in methylmethacrylate, were sectioned, and were stained for histologic examination.Two weeks following coil implantation, aneurysms were filled predominantly with unorganized thrombus. Six weeks following coil implantation, histologic features included complete filling of the aneurysm lumen with either prominent laminated but unorganized thrombus or areas of unorganized thrombus interspersed among areas of cellular infiltration. At 12 weeks following coil implantation, aneurysms were filled with the loosely packed, disordered cells contained within the extracellular matrix. Fibrosis or smooth muscle cell infiltration was not present in any of the 6- or 12-week samples.Platinum coils placed into experimental saccular aneurysms in New Zealand White rabbits failed to elicit a fibrotic response. This model can be used for the testing of biologic modifications of platinum coils aimed at increasing intra-aneurysmal fibrosis.

    View details for Web of Science ID 000082771900037

    View details for PubMedID 10540665

  • Percutaneous vertebroplasty in vertebral osteonecrosis (Kummell's spondylitis). Neurosurgical focus Do, H. M., Jensen, M. E., Marx, W. F., Kallmes, D. F. 1999; 7 (1)

    Abstract

    The authors report the clinical symptoms and response to therapy of a series of patients who presented with subacute or chronic back pain due to vertebral osteonecrosis (Kummell's spondylitis) and who underwent percutaneous vertebroplasty. The authors performed a retrospective chart review of a series of 95 patients in whom 149 painful, nonneoplastic compression fractures were demonstrated and who were treated with percutaneous transpediculate polymethylmethacrylate (PMMA) vertebroplasty. In six of these patients there was evidence of vertebral osteonecrosis, as evidenced by the presence of an intravertebral vacuum cleft on radiography or by intravertebral fluid on magnetic resonance (MR) imaging. Clinical and radiological findings on presentation were noted. Technical aspects of the vertebroplasty technique were compiled. Response to therapy, defined as qualitative change in pain severity and change in level of activity, was noted immediately following the procedure and at various periods on follow-up reviews. One man and five women, who ranged in age from 72 to 90 years (mean 81 years), were treated. Each patient had one compression fracture. The fractures were at T-11 (one patient), L-1 (two patients), L-3 (two patients), and L-4 (one patient). The pain pattern was described as severe and localized to the affected vertebra, and sometimes radiated along either flank. Pain duration ranged from 2 to 12 weeks, and the pain was refractory to conservative therapy that consisted of bedrest, analgesics, and external bracing. At the time of treatment, all patients were bedridden because of severe back pain. In all patients either plain radiographic or computerized tomography evidence of intravertebral vacuum cleft or MR imaging evidence of vertebral fluid collection consistent with avascular necrosis of the vertebral body was demonstrated. Four patients underwent bilateral transpediculate vertebroplasty, and two patients underwent unilateral transpediculate vertebroplasty. The fracture cavities were specifically targeted for PMMA injection. Additional fortification of the osteoporotic vertebral body trabeculae was also performed when feasible. "Cavitygrams" or intraosseous venograms with gentle contrast injection were obtained prior to application of cement mixture. In all patients subjective improvement in pain and increased mobility were demonstrated posttreatment. The follow-up period ranged from 4 to 24 hours after treatment. Two patients made additional office visits at 1 and 3 months, respectively. Patients presenting with vertebral osteonecrosis (Kummell's spondylitis) often suffer from local paraspinous or referred pain. When performing vertebroplasty on these patients, confirmation of entry into the fracture cavities with contrast-enhanced "cavitygrams" should be performed prior to injection of PMMA cement. The response to vertebroplasty with regard to amelioration of pain and improved mobility is encouraging.

    View details for PubMedID 16918233

  • The fate of neuroradiologic abstracts presented at national meetings in 1993: Rate of subsequent publication in peer-reviewed, indexed journals AMERICAN JOURNAL OF NEURORADIOLOGY Marx, W. F., Cloft, H. J., Do, H. M., Kallmes, D. F. 1999; 20 (6): 1173-1177

    Abstract

    Abstract presentations are a valuable means of rapidly conveying new information; however, abstracts that fail to eventually become published are of little use to the general medical community. Our goals were to determine the publication rate of neuroradiologic papers originally presented at national meetings in 1993 and to assess publication rate as a function of neuroradiologic subspecialty and study design.Proceedings from the 1993 ASNR and RSNA meetings were reviewed. A MEDLINE search encompassing 1993-1997 was performed cross-referencing lead author and at least one text word based on the abstract title. All ASNR and RSNA neuroradiologic abstracts were included. Study type, subspecialty classification, and sample size were tabulated. Publication rate, based on study design and neuroradiologic subspecialty, was compared with overall publication rate. Median duration from meeting presentation to publication was calculated, and the journals of publication were noted.Thirty-seven percent of ASNR abstracts and 33% of RSNA neuroradiologic abstracts were published as articles in indexed medical journals. Publication rates among neuroradiologic subspecialty types were not significantly different. Prospective studies presented at the ASNR were published at a higher rate than were retrospective studies. There was no difference between the publication rate of experimental versus clinical studies. Neuroradiologic abstracts were published less frequently than were abstracts within other medical specialties. Median time between abstract presentation and publication was 15 months.Approximately one third of neuroradiologic abstracts presented at national meetings in 1993 were published in indexed journals. This rate is lower than that of abstracts from medical specialties other than radiology.

    View details for Web of Science ID 000081922100042

    View details for PubMedID 10445467

  • Experimental side-wall aneurysms: a natural history study NEURORADIOLOGY Kallmes, D. F., Altes, T. A., Vincent, D. A., Cloft, H. J., Do, H. M., Jensen, M. E. 1999; 41 (5): 338-341

    Abstract

    We studied the natural history of canine side-wall experimental aneurysms to determine the incidence of spontaneous aneurysm thrombosis, to serve as control data for future studies focusing on development of aneurysm occlusion devices. Bilateral common carotid artery vein patch aneurysms were surgically created in eight mongrel dogs (20-25 kg). Duplex Doppler sonography was performed at 14 days and angiography between 30 and 210 days following aneurysm creation. Sonography demonstrated patency of 13 (81%) of 16 aneurysms. Patent aneurysms ranged in size from 8 x 10 mm to 14 x 16 mm. Conventional angiography was performed in four dogs approximately 30 days following aneurysm creation; in these four, all of 7 initially patent on sonography remained fully patent. One dog underwent conventional angiography at approximately 60 days following aneurysm creation; both aneurysms in this case remained widely patent. Three dogs underwent conventional angiography at approximately 200 days following aneurysm creation; all 4 aneurysms initially patent on sonography remained fully patent. None of the three aneurysms found to be occluded on sonographs demonstrated spontaneous recanalization. The canine side-wall aneurysm model is a valid tool for testing some aneurysm-occlusion devices, because control aneurysms remain patent indefinitely.

    View details for Web of Science ID 000080530600006

    View details for PubMedID 10379590

  • Perfusion imaging of the human lung using Flow-Sensitive Alternating Inversion Recovery with an Extra Radiofrequency pulse (FAIRER) MAGNETIC RESONANCE IMAGING Mai, V. M., Hagspiel, K. D., Christopher, J. M., Do, H. M., Altes, T., Knight-Scott, J., Stith, A. L., Maier, T., Berr, S. S. 1999; 17 (3): 355-361

    Abstract

    Pulmonary perfusion is an important parameter in the evaluation of lung diseases such as pulmonary embolism. A noninvasive MR perfusion imaging technique of the lung is presented in which magnetically labeled blood water is used as an endogenous, freely diffusible tracer. The perfusion imaging technique is an arterial spin tagging method called Flow sensitive Alternating Inversion Recovery with an Extra Radiofrequency pulse (FAIRER). Seven healthy human volunteers were studied. High-resolution perfusion-weighted images with negligible artifacts were acquired within a single breathhold. Different patterns of signal enhancement were observed between the pulmonary vessels and parenchyma, which persists up to TI = 1400 ms. The T1s of blood and lung parenchyma were determined to be 1.46s and 1.35 s, respectively.

    View details for Web of Science ID 000079291000004

    View details for PubMedID 10195578

  • Spinal cord infarction complicating embolisation of vertebral metastasis - A result of masking of a spinal artery by a high-flow lesion INTERVENTIONAL NEURORADIOLOGY Cloft, H. J., Jensen, M. E., Do, H. M., Kallmes, D. F. 1999; 5 (1): 61-65

    Abstract

    Summary: A 70-year-old woman presented with severe back pain secondary to metastasis of renal cell carcinoma to the second lumbar vertebral body. She had no evidence of spinal cord compression clinically or on MR imaging. Tumour embolisation was performed for pain relief The embolisation was complicated by spinal cord infarction resulting from angiographic masking of a spinal artery by diversion of contrast material into the high-flow tumour.

    View details for Web of Science ID 000080629500011

    View details for PubMedID 20670493

  • Dural arteriovenous fistula of the cervical spine presenting with subarachnoid hemorrhage AMERICAN JOURNAL OF NEURORADIOLOGY Do, H. M., Jensen, M. E., Cloft, H. J., Kallmes, D. E., Dion, J. E. 1999; 20 (2): 348-350

    Abstract

    We describe a case of dural arteriovenous fistula (DAVF) presenting with subarachnoid hemorrhage (SAH). The diagnosis of DAVF was based on spinal angiography. A review of the literature revealed that five of 13 previously reported DAVFs of the cervical spine were accompanied by SAH. SAH has not been observed in DAVFs involving other segments of the spinal canal.

    View details for Web of Science ID 000078982400037

    View details for PubMedID 10094368

  • Posterior inferior cerebellar artery aneurysms associated with posterior fossa arteriovenous malformation - Report of five cases and literature review SURGICAL NEUROLOGY Kaptain, G. J., Lanzino, G., Do, H. M., Kassell, N. F. 1999; 51 (2): 146-152

    Abstract

    The association of posterior inferior cerebellar artery (PICA) aneurysms with posterior fossa arteriovenous malformation (AVM) is uncommon. Over the past 3 years, five patients with this condition were treated at this institution. A review of the clinical history of these and other reported cases has illuminated common threads in the presentation, treatment, and outcome of these lesions.The findings of 27 patients (5 from our institution and 22 from the medical literature) with PICA aneurysms associated with AVMs were reviewed.Eighty-four percent of individuals presented with sub-arachnoid hemorrhage (SAH); 89% of these episodes resulted from aneurysm rupture documented by either intraoperative inspection or autopsy. All aneurysms were located on a feeding artery to the AVM, and 81% originated from distal portions of PICA. The majority of patients presented with Hunt & Hess grade I SAH; all patients who presented with hemorrhage were treated surgically. Surgical strategy was directed both to secure the aneurysm and to resect the AVM during the course of a single procedure. Although four individuals either died on admission or in the perioperative period, overall outcome was excellent or good in 82% of patients.PICA aneurysms associated with AVMs most often involve the distal segments of the artery. Patients usually present with SAH secondary to aneurysmal rupture. Surgical clipping of the aneurysm and excision of the AVM is possible in a single procedure with minimal morbidity. Overall prognosis is favorable in 80% of the cases.

    View details for Web of Science ID 000078645900016

    View details for PubMedID 10029418

  • Complete duplication or extreme fenestration of the basilar artery AMERICAN JOURNAL OF NEURORADIOLOGY Goldstein, J. H., Woodcock, R., Do, H. M., Phillips, C. D., Dion, J. E. 1999; 20 (1): 149-150

    Abstract

    We describe a 42-year-old man with complete duplication or extreme fenestration of the basilar artery. We review the developmental anatomy and embryology and discuss the possible clinical implications and associated findings of this anomaly.

    View details for Web of Science ID 000078385300026

    View details for PubMedID 9974071

  • CT-guided percutaneous drainage of syringomyelia JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Goldstein, J. H., Kaptain, G. J., Do, H. M., Cloft, H. J., Jane, J. A., Phillips, C. D. 1998; 22 (6): 984-988

    Abstract

    Our purpose is to describe CT-guided percutaneous drainage of syringomyelia as a possible contribution in patient management.CT-guided percutaneous drainage was performed on three patients with symptomatic syringomyelia. We determined the success of percutaneous decompression by subsequent CT and MRI. The effect of syringomyelia decompression in relation to the patient's symptoms was determined. This information was then used to help guide clinical management.In Case 1, percutaneous drainage of a large syrinx in a C5 quadriplegic patient with increasing lower extremity spasticity demonstrated significant decompression by imaging but did not result in clinical improvement. A surgical procedure to decompress the syrinx was not performed on the basis of this information. In Case 2, percutaneous drainage of a large syrinx in a quadriplegic patient with increasing upper extremity numbness and weakness demonstrated significant decompression by imaging and resulted in sustained clinical improvement, temporarily obviating the need for surgery. In Case 3, percutaneous drainage of the rostral aspect of a septated syrinx cavity in a patient with a Chiari I malformation and a syringoperitoneal shunt in place resulted in decompression by imaging but failed to relieve the patient's newly developed symptoms. An additional shunt was therefore not placed. In no case did the patient experience periprocedural complications or worsening of symptoms.CT-guided percutaneous drainage of syringomyelia is a safe and successful technique. It can be used diagnostically to identify patients that may or may not benefit from surgical syrinx decompression and in some cases may provide a temporary therapeutic alternative to surgery.

    View details for Web of Science ID 000077124400026

    View details for PubMedID 9843244

  • Brown-Sequard syndrome of the cervical spinal cord after chiropractic manipulation AMERICAN JOURNAL OF NEURORADIOLOGY Lipper, M. H., Goldstein, J. H., Do, H. M. 1998; 19 (7): 1349-1352

    Abstract

    We report a case of increased signal in the left hemicord at the C4 level on T2-weighted MR images after chiropractic manipulation, consistent with contusion. The patient displayed clinical features of Brown-Séquard syndrome, which stabilized with immobilization and steroids. Follow-up imaging showed decreased cord swelling with persistent increased signal. After physical therapy, the patient regained strength on the left side, with residual decreased sensation to pain involving the right arm.

    View details for Web of Science ID 000075475900037

    View details for PubMedID 9726481

  • Patterns of hemorrhage with ruptured posterior inferior cerebellar artery aneurysms: CT findings in 44 cases AMERICAN JOURNAL OF ROENTGENOLOGY Kallmes, D. F., Lanzino, G., Dix, J. E., Dion, J. E., Do, H., Woodcock, R. J., Kassell, N. F. 1997; 169 (4): 1169-1171

    Abstract

    We intended to characterize the CT patterns of hemorrhage associated with ruptured posterior inferior cerebellar artery (PICA) aneurysms.CT scans of 44 cases of angiographically confirmed ruptured saccular PICA aneurysms (4) aneurysms at the junction of the vertebral artery and the PICA and three distal PICA aneurysms) were retrospectively reviewed. All scans had been obtained within 2 days of the subarachnoid hemorrhage (SAH) (day 0 [less than 24 hr], 35 patients; day 1, eight patients; day 2, one patient). Presence or absence of hemorrhage in specific subarachnoid, intraventricular, and intraparenchymal locations was noted, as were the presence and degree of hydrocephalus.Posterior fossa SAH was present in 95% of cases. Isolated posterior fossa SAH was present in 30% of cases, but in no case was isolated supratentorial SAH present. Supratentorial SAH was present in 70% of cases. SAH involving the sylvian fissure or the interhemispheric region was present in 25% and 23% of cases, respectively. SAH along the convexity was present in 2% of cases. Intraventricular hemorrhage (IVH) with or without associated SAH was seen in 95% of cases, whereas isolated IVH was seen in 5% of cases. Hydrocephalus was present in 95% of cases and was moderate to marked in 70%. Both IVH and hydrocephalus were present in 93% of cases.Ruptured PICA aneurysms almost always coexist with hydrocephalus and IVH, as seen in 93% of cases, and almost never coexist with SAH along the convexity. The most common pattern of hemorrhage associated with such aneurysms includes IVH and posterior fossa hemorrhage. Extensive supratentorial SAH, in conjunction with posterior fossa SAH, is a common finding in patients with ruptured PICA aneurysms. SAH isolated to the posterior fossa is present in a sizeable minority of cases.

    View details for Web of Science ID A1997XW98100047

    View details for PubMedID 9308484

  • Ion implantation and protein coating of detachable coils for endovascular treatment of cerebral aneurysms: Concepts and preliminary results in swine models NEUROSURGERY Murayama, Y., Vinuela, F., Suzuki, Y., Do, H. M., Massoud, T. F., Guglielmi, G., Ji, C., Iwaki, M., Kusakabe, M., Kamio, M., Abe, T. 1997; 40 (6): 1233-1243

    Abstract

    Complete anatomic obliteration remains difficult to achieve with endovascular treatment of wide-necked aneurysms using Guglielmi detachable platinum coils (GDCs). Ion implantation is a physicochemical surface modification process resulting from the impingement of a high-energy ion beam. Ion implantation and protein coating were used to alter the surface properties (thrombogenicity, endothelial cellular migration, and adhesion) of GDCs. These modified coils were compared with standard GDCs in the treatment of experimental swine aneurysms.In an initial study, straight platinum coils were used to compare the acute thrombogenicity of standard and modified coils. Modified coils were coated with albumin, fibronectin, or collagen and underwent Ne+ ion implantation at a dose of 1 x 10(15) ions/cm2 and an energy of 150 keV. Coils were placed in common iliac arteries of 17 swine for 1 hour, to evaluate their acute interactions with circulating blood. In a second study, GDCs were used to treat 34 aneurysms in an additional 17 swine. GDCs were coated with fibronectin, albumin, collagen, laminin, fibrinogen, or vitronectin and then implanted with ions as described above. Bilateral experimental swine aneurysms were embolized with standard GDCs on one side and with ion-implanted, protein-coated GDCs on the other side. The necks of aneurysms were evaluated macroscopically at autopsy, by using post-treatment Day 14 specimens. The dimensions of the orifice and the white fibrous membrane that covered the orifice were measured as the fibrous membrane to orifice proportion. Histopathological evaluation of the neck region was performed by light microscopy and scanning electron microscopy.Fibronectin-coated, ion-implanted coils showed the greatest acute thrombogenicity (average thrombus weight for standard coils, 1.9 +/- 1.5 mg; weight for fibronectin-coated coils, 8.6 +/- 6.2 mg; P < 0.0001). By using scanning electron microscopy, an intensive blood cellular response was observed on ion-implanted coil surfaces, whereas this was rare with standard coils. At Day 14, greater fibrous coverage of the necks of aneurysms was observed in the ion-implanted coil group (mean fibrous membrane to orifice proportion of 69.8 +/- 6.2% for the ion-implanted coil group, compared with 46.8 +/- 15.9% for the standard coil group; P = 0.0143).The results of this preliminary experimental study indicate that ion implantation combined with protein coating of GDCs improved cellular adhesion and proliferation. Future application of this technology may provide early wound healing at the necks of embolized, wide-necked, cerebral aneurysms.

    View details for Web of Science ID A1997XC45000058

    View details for PubMedID 9179897

  • ANTERIOR CRUCIATE LIGAMENT TEAR - INDIRECT SIGNS AT MR-IMAGING RADIOLOGY Gentili, A., Seeger, L. L., Yao, L., Do, H. M. 1994; 193 (3): 835-840

    Abstract

    To establish the sensitivity and specificity of indirect signs at magnetic resonance (MR) imaging of anterior cruciate ligament (ACL) tear.MR images of the knees of 89 consecutive patients (54 with torn and 35 with normal ACLs) were reviewed.The indirect signs were as follows (first percentage is sensitivity; the second, specificity): angle between lateral tibial plateau and ACL less than 45 degrees (90%, 97%); angle between Blumenstaat line and ACL more than 15 degrees (89%, 100%); bone contusions in lateral compartment (54%, 100%); position of posterior cruciate ligament (PCL) line (52%, 91%); PCL angle less than 107 degrees (52%, 94%); PCL bowing ratio more than 0.39 (34%, 100%); posterior displacement of lateral meniscus more than 3.5 mm (44%, 94%); anterior displacement of tibia more than 7 mm (41%, 91%); and lateral femoral sulcus deeper than 1.5 mm (19%, 100%).Because the specificity is high, the presence of indirect signs corroborates the diagnosis of ACL tear. Because the sensitivity is low, the absence of these signs does not exclude the diagnosis of ACL tear.

    View details for Web of Science ID A1994PT55300049

    View details for PubMedID 7972834

  • PLANTAR PLATE OF THE FOOT - FINDINGS ON CONVENTIONAL ARTHROGRAPHY AND MR-IMAGING AMERICAN JOURNAL OF ROENTGENOLOGY Yao, L., Do, H. M., Cracchiolo, A., Farahani, K. 1994; 163 (3): 641-644

    Abstract

    The plantar plate of the foot is formed by the plantar aponeurosis and plantar capsule. The plantar plate arises from the distal plantar aspect of the metatarsal neck and inserts on the plantar aspect of the proximal phalangeal base. This thick plate supports the undersurface of the metatarsal head and resists hyperextension of the metatarsophalangeal joint (MTPJ) [1]. Plantar plate rupture may present as lesser metatarsalgia (the lesser metatarsals are the second through fifth), occasionally with exuberant synovitis. Plantar plate derangement also plays a central role in the genesis of the common hammertoe [2, 3]. Rupture or degeneration of the plantar plate destabilizes the MTPJ, allowing dorsal subluxation of the proximal phalanx. The resulting "cock-up" deformity at the MTPJ shortens and compromises the action of the extensor digitorum longus tendon, contributing over time to a flexion deformity at the interphalangeal joints.

    View details for Web of Science ID A1994PF50400030

    View details for PubMedID 8079860

  • BLADDER PHEOCHROMOCYTOMA - COLOR DOPPLER SONOGRAPHIC CORRELATION JOURNAL OF ULTRASOUND IN MEDICINE Cronan, J. J., Do, H. M., Monchik, J. M., Stein, B. S. 1992; 11 (9): 493-495

    View details for Web of Science ID A1992KY02500008

    View details for PubMedID 1491435

  • CT APPEARANCE OF SPLENIC INJURIES MANAGED NONOPERATIVELY AMERICAN JOURNAL OF ROENTGENOLOGY Do, H. M., Cronan, J. J. 1991; 157 (4): 757-760

    Abstract

    This essay illustrates the appearance of the traumatized spleen on CT scans obtained during the course of conservative treatment. Although the CT appearance of acute rupture of the spleen has been adequately described, little has been reported about the appearance of the spleen as it heals after trauma. Examples of CT studies of splenic injuries illustrate the various changes in appearance over time in the traumatized spleen that is treated nonoperatively.

    View details for Web of Science ID A1991GF74300016

    View details for PubMedID 1892031

Conference Proceedings


  • Adjuvant use of epsilon-aminocaproic acid (Amicar) in the endovascular treatment of cranial arteriovenous fistulae Kallmes, D. F., Marx, W. F., Jensen, M. E., Cloft, H. J., Do, H. M., Lanzino, G., West, K., Dion, J. E. SPRINGER. 2000: 302-308

    Abstract

    We report our experience with the use of the antifibrinolytic agent epsilon-aminocaproic acid (EACA), Amicar, as an adjuvant to endovascular treatment of cranial arteriovenous fistulae. We also review applications of antifibrinolytic agents to neurovascular disorders and discuss the mechanism of action, dosing strategy, contraindications, and possible complications associated with the use of EACA. We identified 13 patients with cranial arteriovenous fistulae (five direct carotid cavernous fistulae [CCF], seven dural arteriovenous fistulae [DAVF], and one vein of Galen malformation) who received EACA as an adjunct to endovascular treatment. In all cases embolic coils were the primary embolic agent. We reviewed the modes of initial endovascular therapy and angiographic findings immediately thereafter and the response to EACA. Two direct CCF and two DAVF were completely thrombosed on follow-up angiography, and two DAVF demonstrated diminished flow after EACA therapy. Seven fistulae did not respond to EACA. Four of eight tightly coiled fistulae thrombosed, while none of five loosely coiled fistulae thrombosed. None of four cases with a residual fistula separate from the coil mass underwent thrombosis with EACA, while four of nine cases without a separate fistula thrombosed. There was no morbidity related to EACA therapy. EACA may thus be useful as an adjunct to endovascular treatment of cranial arteriovenous fistulae. Loose or incomplete coil packing of the fistula predicts a poor response to EACA therapy.

    View details for Web of Science ID 000087064800013

    View details for PubMedID 10872177

  • Complications of peritoneal dialysis: Evaluation with CT peritoneography Cochran, S. T., Do, H. M., Ronaghi, A., Nissenson, A. R., Kadell, B. M. RADIOLOGICAL SOC NORTH AMER. 1997: 869-878

    Abstract

    Computed tomographic (CT) peritoneography involves CT of the abdomen and pelvis after administration of a mixture of contrast material and dialysate. CT peritoneography can demonstrate a variety of complications of continuous ambulatory peritoneal dialysis. In patients with symptoms of peritonitis, CT peritoneography is better than conventional CT in demonstrating loculated fluid collections and indicates adhesions by means of uneven distribution of the contrast material-dialysate mixture. In patients with edema or abdominal bulging, CT peritoneography reliably shows the site of dialysate leakage and allows differentiation of a leak from a hernia. In patients with problems of fluid return, catheter malposition and its effect on dialysate distribution can be determined with CT peritoneography. In patients with poor ultrafiltration, demonstration of restricted space in the pelvis or poor distribution of fluid with CT peritoneography suggests adhesions. CT peritoneography also provides anatomic information for referring physicians that may determine whether treatment is medical or surgical.

    View details for Web of Science ID A1997XH28200007

    View details for PubMedID 9225388

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