A potential new role for ASL perfusion imaging: Diagnosis of metronidazole induced encephalopathy - Two companion cases.
Radiology case reports
2020; 15 (1): 77?81
Ferumoxytol-enhanced MRI for surveillance of pediatric cerebral arteriovenous malformations.
Journal of neurosurgery. Pediatrics
Metronidazole induced encephalopathy (MIE) is a rare condition due to prolonged high dose administration of metronidazole. MIE with corresponding increased perfusion on MRI arterial spin labeling (ASL) of the involved regions of the brain appears not to have been reported in the literature to date. We present two such cases, a 59-year-old male with recurrent C difficile colitis with classic MR imaging characteristics of MIE, and a companion case of a 65-year-old female with gangrenous cholecystitis also presumed to have MIE. Despite aggressive medical management, both patients expired. Our cases demonstrate a correlation with ASL hyperperfusion to affected brain regions thought to be due to edema or inflammation. Perfusion imaging may play a role in diagnosis of MIE.
View details for DOI 10.1016/j.radcr.2019.10.011
View details for PubMedID 31737151
Imaging Evaluation of the Adult Presenting With New-Onset Seizure.
AJR. American journal of roentgenology
Children with intracranial arteriovenous malformations (AVMs) undergo digital DSA for lesion surveillance following their initial diagnosis. However, DSA carries risks of radiation exposure, particularly for the growing pediatric brain and over lifetime. The authors evaluated whether MRI enhanced with a blood pool ferumoxytol (Fe) contrast agent (Fe-MRI) can be used for surveillance of residual or recurrent AVMs.A retrospective cohort was assembled of children with an established AVM diagnosis who underwent surveillance by both DSA and 3-T Fe-MRI from 2014 to 2016. Two neuroradiologists blinded to the DSA results independently assessed Fe-enhanced T1-weighted spoiled gradient recalled acquisition in steady state (Fe-SPGR) scans and, if available, arterial spin labeling (ASL) perfusion scans for residual or recurrent AVMs. Diagnostic confidence was examined using a Likert scale. Sensitivity, specificity, and intermodality reliability were determined using DSA studies as the gold standard. Radiation exposure related to DSA was calculated as total dose area product (TDAP) and effective dose.Fifteen patients were included in this study (mean age 10 years, range 3-15 years). The mean time between the first surveillance DSA and Fe-MRI studies was 17 days (SD 47). Intermodality agreement was excellent between Fe-SPGR and DSA (? = 1.00) but poor between ASL and DSA (? = 0.53; 95% CI 0.18-0.89). The sensitivity and specificity for detecting residual AVMs using Fe-SPGR were 100% and 100%, and using ASL they were 72% and 100%, respectively. Radiologists reported overall high diagnostic confidence using Fe-SPGR. On average, patients received two surveillance DSA studies over the study period, which on average equated to a TDAP of 117.2 Gy×cm2 (95% CI 77.2-157.4 Gy×cm2) and an effective dose of 7.8 mSv (95% CI 4.4-8.8 mSv).Fe-MRI performed similarly to DSA for the surveillance of residual AVMs. Future multicenter studies could further investigate the efficacy of Fe-MRI as a noninvasive alternative to DSA for monitoring AVMs in children.
View details for DOI 10.3171/2019.5.PEDS1957
View details for PubMedID 31323627
Rapid-sequence brain magnetic resonance imaging for Chiari I abnormality
JOURNAL OF NEUROSURGERY-PEDIATRICS
2018; 22 (2): 158?64
OBJECTIVE: The purpose of this study is to discuss the evidence supporting the use of neuroimaging in adult patients presenting with new-onset seizure.CONCLUSION: Unenhanced CT should be the initial imaging examination performed for adults presenting with first unprovoked seizure in the acute setting to exclude conditions requiring urgent or emergent intervention. MRI has added benefits and should be considered for adults presenting acutely for whom the initial CT is negative and for those presenting with new-onset seizure in the nonacute setting.
View details for PubMedID 30299997
Vertical diplopia and oscillopsia due to midbrain keyhole aqueduct syndrome associated with severe cough.
American journal of ophthalmology case reports
2018; 10: 128?31
OBJECTIVE Fast magnetic resonance imaging (fsMRI) sequences are single-shot spin echo images with fast acquisition times that have replaced CT scans for many conditions. Introduced as a means of evaluating children with hydrocephalus and macrocephaly, these sequences reduce the need for anesthesia and can be more cost-effective, especially for children who require multiple surveillance scans. However, the role of fsMRI has yet to be investigated in evaluating the posterior fossa in patients with Chiari I abnormality (CM-I). The goal of this study was to examine the diagnostic performance of fsMRI in evaluating the cerebellar tonsils in comparison to conventional MRI. METHODS The authors performed a retrospective analysis of 18 pediatric patients with a confirmed diagnosis of CM-I based on gold-standard conventional brain MRI and 30 controls without CM-I who had presented with various neurosurgical conditions. The CM-I patients were included if fsMRI studies had been obtained within 1 year of conventional MRI with no surgical intervention between the studies. Two neuroradiologists reviewed the studies in a blinded fashion to determine the diagnostic performance of fsMRI in detecting CM-I. For the CM-I cohort, the fsMRI and T2-weighted MRI exams were randomized, and the blinded reviewers performed tonsillar measurements on both scans. RESULTS The mean age of the CM-I cohort was 7.39 years, and 50% of these subjects were male. The mean time interval between fsMRI and conventional T2-weighted MRI was 97.8 days. Forty-four percent of the subjects had undergone imaging after posterior fossa decompression. The sensitivity and specificity of fsMRI in detecting CM-I was 100% (95% CI 71.51%-100%) and 92.11% (95% CI 78.62%-98.34%), respectively. If only preoperative patients are considered, both sensitivity and specificity increase to 100%. The authors also performed a cost analysis and determined that fsMRI was significantly cost-effective compared to T2-weighted MRI or CT. CONCLUSIONS Despite known limitations, fsMRI may serve as a useful diagnostic and surveillance tool for CM-I. It is more cost-effective than full conventional brain MRI and decreases the need for sedation in young children.
View details for PubMedID 29749883
Temporal Bone CT Scan for Malleal Ligaments Assessment.
Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology
2018; 39 (10): e1054?e1059
Purpose: Midline structural defects in the neural axis can give rise to neuro-ophthalmic symptoms. We report a rare case of keyhole aqueduct syndrome presenting after two years of severe cough due to gastroesophageal reflux disease.Observations: A 58-year-old woman with a 2-year history of daily, severe cough presented to the neuro-ophthalmology clinic with progressive diplopia and oscillopsia. Examination revealed a 1-2 Hz down-beating nystagmus in primary gaze that worsened with left, right, and down gazes. Gaze evoked nystagmus and mild paresis were also seen with up gaze. There was an incomitant left hypertropia due to skew deviation that worsened with right and up gazes and improved with down gaze. She also had a right-sided ptosis and a 3 mm anisocoria not due to cranial nerve 3 paresis or Horner's syndrome. Brain magnetic resonance imaging showed a 1.5?mm?*?11.7?mm?*?6?mm?midline cleft in the ventral midbrain communicating with the cerebral aqueduct, consistent with keyhole aqueduct syndrome. Her nystagmus and diplopia improved with oral acetazolamide treatment, at high doses of 2500-3000 mg per day.Conclusions and importance: We report the first case of midbrain keyhole aqueduct syndrome with ocular motor and other neuro-ophthalmic manifestations associated with severe cough. Although her cough was effectively treated and intracranial pressure measurement was normal, her ophthalmic symptoms continued to progress, which is common in previous cases reported. Treatment with acetazolamide led to significant improvement, supporting the use of acetazolamide in this rare condition.
View details for PubMedID 29687086
Advanced MRI Measures of Cerebral Perfusion and Their Clinical Applications.
Topics in magnetic resonance imaging
2017; 26 (2): 83-90
To determine the feasibility of using temporal bone computed tomography (CT) scans to identify malleal ligaments and the prevalence of calcification in malleal ligaments.Retrospective case review. CT scans were blindly and retrospectively reviewed by two physicians (a radiologist and a nonradiologist). Scans differed by slice thickness, and included both conventional CT and cone beam CT (CBCT).Ambulatory tertiary referral center.One hundred fifty-one temporal bone CT scans, obtained between the years 2014 and 2017, were initially screened, which included 302 ears. Patients with previous tympanomastoid surgery or middle ear opacification were excluded, leaving 187 ears in the study.Diagnostic.Percentage of visible normal and calcified malleal ligaments.Scans with submillimeter slice thickness were more likely to demonstrate all three malleal ligaments than those with 1 ml and larger slices (83.7% versus 50.0% for nonradiologist, p?0.0001; 59.6 versus 34.8% for radiologist, p?0.0001). Calcification was seen in 11.8% of ears reviewed. The ability to detect malleal ligaments with cone beam CT was 86.2%, while the rate with conventional CT was 71.1%, a difference that persisted when controlling for slice thickness. Interobserver agreement for the detection of malleal ligaments was 65% with a Cohen's kappa coefficient of ??=?0.27.Visualization of the malleal ligaments using CT scans is feasible in a majority of aerated ears. Detection of malleal ligaments improves with thinner slice thickness and cone-beam technique. Low interobserver agreement suggests the importance of experience and a need for standardized review.
View details for PubMedID 30239436
Cerebral blood flow measurement by magnetic resonance imaging perfusion (MRP) techniques is broadly applied to patients with acute ischemic stroke, vasospasm following aneurysmal subarachnoid hemorrhage, chronic arterial steno-occlusive disease, cervical atherosclerotic disease, and primary brain neoplasms. MRP may be performed using an exogenous tracer, most commonly gadolinium-based intravenous contrast, or an endogenous tracer, such as arterial spin labeling (ASL) or intravoxel incoherent motion (IVIM). Here, we review the technical basis of commonly performed MRP techniques, the interpretation of MRP imaging maps, and how MRP provides valuable clinical information in the triage of patients with cerebral disease.
View details for DOI 10.1097/RMR.0000000000000120
View details for PubMedID 28277457