Bio

Clinical Focus


  • Pediatric Neuroradiology
  • Diagnostic Radiology

Academic Appointments


Professional Education


  • Board Certification: Neuroradiology, American Board of Radiology (2008)
  • Board Certification: Diagnostic Radiology, American Board of Radiology (2006)
  • Fellowship, Stanford University, Neuroradiology (2008)
  • Residency:UCLA Medical Center (2006) CA
  • Internship:Oakwood Healthcare System (2002) MI
  • Medical Education:University of Michigan (2001) MI

Teaching

2013-14 Courses


Publications

Journal Articles


  • Tectal pineal cyst in a 1-year-old girl. Human pathology Plowey, E. D., Vogel, H., Yeom, K. W., Jung, H., Chao, K., Edwards, M. S. 2014; 45 (3): 653-656

    Abstract

    Glial cysts of the pineal gland can frequently be found in adults and children, but only rarely do they enlarge to become clinically relevant. We report a unique presentation of a pineal cyst in the midbrain tectum of a 16-month-old girl who initially presented with ptosis and strabismus. Preoperative imaging studies and intraoperative findings revealed no continuity between the tectal cyst and the pineal gland proper. We surmise that this tectal pineal cyst may have arisen from duplicated pineal gland tissue.

    View details for DOI 10.1016/j.humpath.2013.10.002

    View details for PubMedID 24411061

  • Diffusion-weighted MRI derived apparent diffusion coefficient identifies prognostically distinct subgroups of pediatric diffuse intrinsic pontine glioma. Journal of neuro-oncology Lober, R. M., Cho, Y., Tang, Y., Barnes, P. D., Edwards, M. S., Vogel, H., Fisher, P. G., Monje, M., Yeom, K. W. 2014; 117 (1): 175-182

    Abstract

    While pediatric diffuse intrinsic pontine gliomas (DIPG) remain fatal, recent data have shown subgroups with distinct molecular biology and clinical behavior. We hypothesized that diffusion-weighted MRI can be used as a prognostic marker to stratify DIPG subsets with distinct clinical behavior. Apparent diffusion coefficient (ADC) values derived from diffusion-weighted MRI were computed in 20 consecutive children with treatment-naïve DIPG tumors. The median ADC for the cohort was used to stratify the tumors into low and high ADC groups. Survival, gender, therapy, and potential steroid effects were compared between the ADC groups. Median age at diagnosis was 6.6 (range 2.3-13.2) years, with median follow-up seven (range 1-36) months. There were 14 boys and six girls. Seventeen patients received radiotherapy, five received chemotherapy, and six underwent cerebrospinal fluid diversion. The median ADC of 1,295 × 10(-6) mm(2)/s for the cohort partitioned tumors into low or high diffusion groups, which had distinct median survivals of 3 and 13 months, respectively (log-rank p < 0.001). Low ADC tumors were found only in boys, whereas high ADC tumors were found in both boys and girls. Available tissue specimens in three low ADC tumors demonstrated high-grade histology, whereas one high ADC tumor demonstrated low-grade histology with a histone H3.1 K27M mutation and high-grade metastatic lesion at autopsy. ADC derived from diffusion-weighted MRI may identify prognostically distinct subgroups of pediatric DIPG.

    View details for DOI 10.1007/s11060-014-1375-8

    View details for PubMedID 24522717

  • Surveillance imaging in children with malignant CNS tumors: low yield of spine MRI. Journal of neuro-oncology Perreault, S., Lober, R. M., Carret, A., Zhang, G., Hershon, L., Décarie, J., Vogel, H., Yeom, K. W., Fisher, P. G., Partap, S. 2014; 116 (3): 617-623

    Abstract

    Magnetic resonance imaging (MRI) is routinely obtained in patients with central nervous system (CNS) tumors, but few studies have been conducted to evaluate this practice. We assessed the benefits of surveillance MRI and more specifically spine MRI in a contemporary cohort. We evaluated MRI results of children diagnosed with CNS tumors from January 2000 to December 2011. Children with at least one surveillance MRI following the diagnosis of medulloblastoma (MB), atypical teratoid rhabdoid tumor (ATRT), pineoblastoma (PB), supratentorial primitive neuroectodermal tumor, supratentorial high-grade glioma (World Health Organization grade III-IV), CNS germ cell tumors or ependymoma were included. A total of 2,707 brain and 1,280 spine MRI scans were obtained in 258 patients. 97 % of all relapses occurred in the brain and 3 % were isolated to the spine. Relapse was identified in 226 (8 %) brain and 48 (4 %) spine MRI scans. The overall rate of detecting isolated spinal relapse was 9/1,000 and 7/1,000 for MB patients. MRI performed for PB showed the highest rate for detecting isolated spinal recurrence with 49/1,000. No initial isolated spinal relapse was identified in patients with glioma, supratentorial primitive neuroectodermal tumor and ATRT. Isolated spinal recurrences are infrequent in children with malignant CNS tumors and the yield of spine MRI is very low. Tailoring surveillance spine MRI to patients with higher spinal relapse risk such as PB, MB with metastatic disease and within 3 years of diagnosis could improve allocation of resources without compromising patient care.

    View details for DOI 10.1007/s11060-013-1347-4

    View details for PubMedID 24401959

  • Relapse patterns in pediatric embryonal central nervous system tumors JOURNAL OF NEURO-ONCOLOGY Perreault, S., Lober, R. M., Carret, A., Zhang, G., Hershon, L., Decarie, J., Yeom, K., Vogel, H., Fisher, P. G., Partap, S. 2013; 115 (2): 209-215

    Abstract

    Embryonal tumors of the central nervous system (CNS) share histological features and were therefore initially grouped as primitive neuroectodermal tumors (PNET) and treated similarly. We sought to determine the relapse patterns of specific embryonal CNS tumors. We conducted a historical cohort study of children diagnosed with CNS embryonal tumors from January 2000 to December 2011 in two pediatric neuro-oncology centers. Patients of 21 years of age or younger at time of presentation with a diagnosis of medulloblastoma, supratentorial PNET, pineoblastoma or atypical teratoid/rhabdoid tumor (ATRT) and at least one surveillance MRI were included. A total of 133 patients met inclusion criteria and 49 (37 %) patients relapsed during the observation period. The majority (79 %) of sPNET relapses were local, whereas all (100 %) PB relapses were associated with diffuse leptomeningeal disease. Relapse patterns for MB were more diverse with local recurrence in 27 %, distant recurrence in 35 % and diffuse leptomeningeal disease in 38 %. The frequency of relapses involving the spine differed (p < 0.001) between tumor types (MB 28/55 [51 %], sPNET 3/33 [9 %], ATRT 3/7 [43 %] and PB 12/12 [100 %]). No sPNET patients had isolated spinal relapse (0/14). Embryonal tumors were found to have divergent patterns of recurrence. While medulloblastoma has variable relapse presentations, sPNET relapses locally and pineoblastoma recurs with diffuse leptomeningeal disease involving the spine. These results point toward possibly new upfront treatment stratification among embryonal tumors in accordance with relapse pattern.

    View details for DOI 10.1007/s11060-013-1213-4

    View details for Web of Science ID 000325821900009

    View details for PubMedID 23921420

  • Improved T2* Imaging without Increase in Scan Time: SWI Processing of 2D Gradient Echo. AJNR. American journal of neuroradiology Soman, S., Holdsworth, S. J., Barnes, P. D., Rosenberg, J., Andre, J. B., Bammer, R., Yeom, K. W. 2013; 34 (11): 2092-2097

    Abstract

    BACKGROUND AND PURPOSE:2D gradient-echo imaging is sensitive to T2* lesions (hemorrhages, mineralization, and vascular lesions), and susceptibility-weighted imaging is even more sensitive, but at the cost of additional scan time (SWI: 5-10 minutes; 2D gradient-echo: 2 minutes). The long acquisition time of SWI may pose challenges in motion-prone patients. We hypothesized that 2D SWI/phase unwrapped images processed from 2D gradient-echo imaging could improve T2* lesion detection.MATERIALS AND METHODS:2D gradient-echo brain images of 50 consecutive pediatric patients (mean age, 8 years) acquired at 3T were retrospectively processed to generate 2D SWI/phase unwrapped images. The 2D gradient-echo and 2D SWI/phase unwrapped images were compared for various imaging parameters and were scored in a blinded fashion.RESULTS:Of 50 patients, 2D gradient-echo imaging detected T2* lesions in 29 patients and had normal findings in 21 patients. 2D SWI was more sensitive than standard 2D gradient-echo imaging in detecting T2* lesions (P < .0001). 2D SWI/phase unwrapped imaging also improved delineation of normal venous structures and nonpathologic calcifications and helped distinguish calcifications from hemorrhage. A few pitfalls of 2D SWI/phase unwrapped imaging were noted, including worsened motion and dental artifacts and challenges in detecting T2* lesions adjacent to calvaria or robust deoxygenated veins.CONCLUSIONS:2D SWI and associated phase unwrapped images processed from standard 2D gradient-echo images were more sensitive in detecting T2* lesions and delineating normal venous structures and nonpathologic mineralization, and they also helped distinguish calcification at no additional scan time. SWI processing of 2D gradient-echo images may be a useful adjunct in cases in which longer scan times of 3D SWI are difficult to implement.

    View details for DOI 10.3174/ajnr.A3595

    View details for PubMedID 23744690

  • Increased focal hemosiderin deposition in pediatric medulloblastoma patients receiving radiotherapy at a later age. Journal of neurosurgery. Pediatrics Yeom, K. W., Lober, R. M., Partap, S., Telischak, N., Tsolinas, R., Barnes, P. D., Edwards, M. S. 2013; 12 (5): 444-451

    Abstract

    Object Focal hemosiderin deposition (FHD) is commonly observed on brain MRI scans of patients treated for childhood medulloblastoma (MB). The authors sought to determine the clinical significance of FHD and its relationship to patient age, radiation dose, and cognitive outcomes. Methods A single-institution retrospective study of 93 MB patients at Lucile Packard Children's Hospital at Stanford from 1998 to 2011 identified 41 patients with a negative baseline MRI scan and at least 2 posttreatment MRI scans obtained with T2* gradient recalled echo (GRE). The number and cumulative rate of FHDs detectable by GRE were compared between patients aged 6 years and younger (early age) and aged 7-21 years (late age) at the time of radiotherapy (RT) and between low-dose (1800-2340 cGy) and high-dose (2920-3960 cGy) RT. Results The median age at MB diagnosis was 7.3 years (range 0.9-21.0 years), the median clinical follow-up period was 5.8 years (range 0.8-13.4 years), and the median 5-year overall survival was 81% ± 7%. Of 30 school-aged children with MB, 21 (70%) required special education, and the median IQ of 10 tested patients was 100 (range 50-118). Thirty-three patients (80%) had FHD after a median latency of 1.9 years (range 0.1-5.9 years). Ninety-four percent (436 of 466) of the lesions arose in the supratentorial region of the brain, whereas 29 (6%) resided in the brainstem or the cerebellum. No spinal lesions were observed on routine spine MRI scans using T2 fast spin echo imaging. The mean cumulative lesion rate per year was 2.23 ± 3.05, and this rate was higher in older children at the time of RT compared with younger children (3.23 vs 0.67 per year, p = 0.002) but did not differ among different RT doses (p = 0.395). A child's IQ or need for special education showed no significant correlation with the rate of lesion development or number of lesions. None of the lesions resulted in symptomatic hemorrhage that required surgical intervention. Conclusions More FHD was observed in children treated for MB at the older ages than in those treated at the younger ages. There was no significant association of the incidence of FHD with radiation dose or cognitive outcomes, and none of the lesions required surgical intervention.

    View details for DOI 10.3171/2013.7.PEDS1330

    View details for PubMedID 23992236

  • Reduced Cerebral Arterial Spin-Labeled Perfusion in Children with Neurofibromatosis Type 1 AMERICAN JOURNAL OF NEURORADIOLOGY Yeom, K. W., Lober, R. M., Barnes, P. D., Campen, C. J. 2013; 34 (9): 1823-1828

    Abstract

    BACKGROUND AND PURPOSE:Neurofibromatosis type 1 is associated with increased risk for stroke, cerebral vasculopathy, and neurocognitive deficits, but underlying hemodynamic changes in asymptomatic children remain poorly understood. We hypothesized that children with neurofibromatosis type 1 have decreased cerebral blood flow.MATERIALS AND METHODS:Arterial spin-labeled CBF was measured in 14 children with neurofibromatosis type 1 (median age, 9.7 years; mean, 10.2 years; range, 22 months to 18 years) and compared with age-matched control subjects on 3T MR imaging. Three-dimensional pseudocontinuous spin-echo arterial spin-labeled technique was used. Measurements were obtained at cortical gray matter of bilateral cerebral hemispheres and centrum semiovale by use of the ROI method. Comparison by Mann-Whitney test was used, with Bonferroni-adjusted P values ≤.004 judged as significant.RESULTS:We identified 7 of 12 areas with significantly diminished arterial spin-labeled CBF in patients with neurofibromatosis type 1 compared with control subjects. These areas included the anterior cingulate gyrus (P = .001), medial frontal cortex (P = .004), centrum semiovale (P = .004), temporo-occipital cortex (P = .002), thalamus (P = .001), posterior cingulate gyrus (P = .002), and occipital cortex (P = .001). Among patients with neurofibromatosis type 1, there were no significant differences in these regions on the basis of the presence of neurofibromatosis type 1 spots or neurocognitive deficits.CONCLUSIONS:Reduced cerebral perfusion was seen in children with neurofibromatosis type 1, particularly in the posterior circulation and the vascular borderzones of the middle and posterior cerebral arteries.

    View details for DOI 10.3174/ajnr.A3649

    View details for Web of Science ID 000329848800034

    View details for PubMedID 23764727

  • Prognostic role for diffusion-weighted imaging of pediatric optic pathway glioma. Journal of neuro-oncology Yeom, K. W., Lober, R. M., Andre, J. B., Fisher, P. G., Barnes, P. D., Edwards, M. S., Partap, S. 2013; 113 (3): 479-483

    Abstract

    Optic pathway glioma (OPG) has an unpredictable course, with poor correlation between conventional imaging features and tumor progression. We investigated whether diffusion-weighted MRI (DWI) predicts the clinical behavior of these tumors. Twelve children with OPG (median age 2.7 years; range 0.4-6.2 years) were followed for a median 4.4 years with DWI. Progression-free survival (time to requiring therapy) was compared between tumors stratified by apparent diffusion coefficient (ADC) from initial pre-treatment scans. Tumors with baseline ADC greater than 1,400 × 10(-6) mm(2)/s required treatment earlier than those with lower ADC (log-rank p = 0.002). In some cases, ADC increased leading up to treatment, and declined following treatment with surgery, chemotherapy, or radiation. Baseline ADC was higher in tumors that eventually required treatment (1,562 ± 192 × 10(-6) mm(2)/s), compared with those conservatively managed (1,123 ± 114 × 10(-6) mm(2)/s) (Kruskal-Wallis test p = 0.013). Higher ADC predicted earlier tumor progression in this cohort and in some cases declined after therapy. Evaluation of OPG with DWI may therefore be useful for predicting tumor behavior and assessing treatment response.

    View details for DOI 10.1007/s11060-013-1140-4

    View details for PubMedID 23673514

  • Case series: fractional anisotropy along the trajectory of selected white matter tracts in adolescents born preterm with ventricular dilation. Journal of child neurology Myall, N. J., Yeom, K. W., Yeatman, J. D., Gaman-Bean, S., Feldman, H. M. 2013; 28 (6): 774-780

    Abstract

    This case series assesses white matter microstructure in 3 adolescents born preterm with nonshunted ventricular dilation secondary to intraventricular hemorrhage. Subjects (ages 12-17 years, gestational age 26-29 weeks, birth weight 825-1624 g) were compared to 3 full-term controls (13-17 years, 39-40 weeks, 3147-3345 g) and 3 adolescents born preterm without ventricular dilation (10-13 years, 26-29 weeks, 630-1673 g). Tractography using a 2 region of interest method reconstructed the following white matter tracts: superior longitudinal/arcuate fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, uncinate fasciculus, and corticospinal tract. Subjects showed increased fractional anisotropy and changes in the pattern of fractional anisotropy along the trajectory of tracts adjacent to the lateral ventricles. Tensor shape at areas of increased fractional anisotropy demonstrated increased linear anisotropy at the expense of planar and spherical anisotropy. These findings suggest increased axonal packing density and straightening of fibers secondary to ventricular enlargement.

    View details for DOI 10.1177/0883073812449693

    View details for PubMedID 22859695

  • Diffusion-Weighted MRI: Distinction of Skull Base Chordoma from Chondrosarcoma. AJNR. American journal of neuroradiology Yeom, K. W., Lober, R. M., Mobley, B. C., Harsh, G., Vogel, H., Allagio, R., Pearson, M., Edwards, M. S., Fischbein, N. J. 2013; 34 (5): 1056-1061

    Abstract

    Chordoma and chondrosarcoma of the skull base are rare tumors with overlapping presentations and anatomic imaging features but different prognoses. We hypothesized that these tumors might be distinguished by using diffusion-weighted MR imaging.We retrospectively reviewed 19 patients with pathologically confirmed chordoma or chondrosarcoma who underwent both conventional and diffusion-weighted MR imaging. Differences in distributions of ADC were assessed by the Kruskal-Wallis test. Associations between histopathologic diagnosis and conventional MR imaging features (T2 signal intensity, contrast enhancement, and tumor location) were assessed with the Fisher exact test.Chondrosarcoma was associated with the highest mean ADC value (2051 ± 261 × 10(-6) mm(2)/s) and was significantly different from classic chordoma (1474 ± 117 × 10(-6) mm(2)/s) and poorly differentiated chordoma (875 ± 100 × 10(-6) mm(2)/s) (P < .001). Poorly differentiated chordoma was characterized by low T2 signal intensity (P = .001), but other conventional MR imaging features of enhancement and/or lesion location did not reliably distinguish these tumor types.Diffusion-weighted MR imaging may be useful in assessing clival tumors, particularly in differentiating chordoma from chondrosarcoma. A prospective study of a larger cohort will be required to determine the value of ADC in predicting histopathologic diagnosis.

    View details for DOI 10.3174/ajnr.A3333

    View details for PubMedID 23124635

  • Case Report of Subdural Hematoma in a Patient With Sturge-Weber Syndrome and Literature Review: Questions and Implications for Therapy JOURNAL OF CHILD NEUROLOGY Lopez, J., Yeom, K. W., Comi, A., Van Haren, K. 2013; 28 (5): 672-675

    Abstract

    Sturge-Weber syndrome is a neurocutaneous disorder associated with vascular abnormalities in the skin, eye, and brain leading to both acute and chronic cerebral hypoperfusion and, in some affected children, brain injury. Aspirin can reduce stroke-like events and seizure episodes and prevent further brain injuries in these patients. Although a few cases of intracranial hemorrhage in patients with Sturge-Weber syndrome have been reported, prior reports have not discussed this complication with regard to particular therapies. The authors present a toddler with Sturge-Weber syndrome who developed a subdural hematoma in the setting of a mechanical fall with minor head trauma. They discuss the possible role of aspirin in contributing to, or perhaps protecting against, intracranial hemorrhage in patients with Sturge-Weber syndrome. Further data are needed to establish the utility of aspirin in Sturge-Weber syndrome.

    View details for DOI 10.1177/0883073812449514

    View details for Web of Science ID 000317683900018

    View details for PubMedID 22805242

  • Comparison of the diagnostic value of MR imaging and ophthalmoscopy for the staging of retinoblastoma EUROPEAN RADIOLOGY Khurana, A., Eisenhut, C. A., Wan, W., Ebrahimi, K. B., Patel, C., O'Brien, J. M., Yeom, K., Daldrup-Link, H. E. 2013; 23 (5): 1271-1280

    Abstract

    To compare the diagnostic value of magnetic resonance (MR) imaging and ophthalmoscopy for staging of retinoblastoma.MR and ophthalmoscopic images of 36 patients who underwent enucleation were evaluated retrospectively following institutional review board approval. Histopathology being the standard of reference, the sensitivity and specificity of both diagnostic modalities were compared regarding growth pattern, iris neoangiogenesis, retinal detachment, vitreous seeds and optic nerve invasion. Data were analysed via McNemar's test.Both investigations showed no significant difference in accuracy for the detection of different tumour growth patterns (P = 0.80). Vitreous seeding detection was superior by ophthalmoscopy (P < 0.001). For prelaminar optic nerve invasion, MR imaging showed similar sensitivity as ophthalmoscopy but increased specificity of 40 % (CI 0.12-0.74) vs. 20 % (0.03-0.56). MR detected optic nerve involvement past the lamina cribrosa with a sensitivity of 80 % (0.28-0.99) and a specificity of 74 % (0.55-0.88). The absence of optic nerve enhancement excluded histopathological infiltration, but the presence of optic nerve enhancement included a high number of false positives (22-24 %).Ophthalmoscopy remains the method of choice for determining extent within the globe while MR imaging is useful for evaluating extraocular tumour extension. Thus, both have their own strengths and contribute uniquely to the staging of retinoblastoma.• Ophthalmoscopy: method of choice for determining extent of retinoblastoma within the globe. • MR imaging provides optimal evaluation of extrascleral and extraocular tumour extension. • Positive enhancement of the optic nerve on MRI does not necessarily indicate involvement.

    View details for DOI 10.1007/s00330-012-2707-8

    View details for Web of Science ID 000317427500015

    View details for PubMedID 23160663

  • Comparison of Readout-Segmented Echo-Planar Imaging (EPI) and Single-Shot EPI in Clinical Application of Diffusion-Weighted Imaging of the Pediatric Brain. AJR. American journal of roentgenology Yeom, K. W., Holdsworth, S. J., Van, A. T., Iv, M., Skare, S., Lober, R. M., Bammer, R. 2013; 200 (5): W437-43

    Abstract

    OBJECTIVE. Readout-segmented echo-planar imaging (EPI) has been suggested as an alternative to single-shot EPI for diffusion-weighted imaging (DWI) with reduced distortion. However, clinical comparisons of readout-segmented EPI and EPI DWI are limited by unmatched imaging parameters and reconstruction procedures. Our goal was to compare the clinical utility of generalized autocalibrating partial parallel acquisition (GRAPPA)-accelerated readout-segmented EPI DWI with GRAPPA-accelerated EPI DWI for visualization of the pediatric brain in regions prone to distortion, such as the orbit, skull base, and posterior fossa. SUBJECTS AND METHODS. Thirty consecutive patients (mean age, 7.8 years) presenting with orbital, skull base, and posterior fossa neuropathologic abnormalities were scanned at 3 T. Images were obtained using GRAPPA-accelerated readout-segmented EPI and GRAPPA-accelerated EPI with an identical scanning time, acceleration factor, target resolution, and image postprocessing procedure. The two datasets were independently reviewed by two blinded neuroradiologists. Imaging studies were evaluated for resolution, signal-to-noise ratio (SNR), contrast, distortion, lesion conspicuity, and diagnostic confidence and graded using a 7-point Likert scale (1, nondiagnostic; 7, outstanding). RESULTS. There was good reader agreement in the scores (? = 0.66; 95% CI, 0.54-0.78). The mean scores for EPI and readout-segmented EPI, respectively, were as follows: resolution, 5.0 and 6.0; SNR, 5.5 and 3.0; contrast, 3.7 and 3.2; distortion, 4.8 and 6.0; lesion conspicuity, 4.6 and 5.1; and diagnostic confidence, 4.7 and 5.4. Readout-segmented EPI was superior in resolution, distortion reduction, lesion conspicuity, and diagnostic confidence, whereas EPI scored better in SNR and contrast. Readout-segmented EPI was considered the better sequence overall in 85% of the cases. CONCLUSION. This study shows the benefits of improved resolution and reduced distortion of readout-segmented EPI in evaluating the orbit, skull base, and posterior fossa, sites of common neuropathologic abnormalities in children.

    View details for DOI 10.2214/AJR.12.9854

    View details for PubMedID 23617511

  • Distinctive MRI Features of Pediatric Medulloblastoma Subtypes AMERICAN JOURNAL OF ROENTGENOLOGY Yeom, K. W., Mobley, B. C., Lober, R. M., Andre, J. B., Partap, S., Vogel, H., Barnes, P. D. 2013; 200 (4): 895-903

    Abstract

    We hypothesized that the apparent diffusion coefficient (ADC) and other MRI features can be used to predict medulloblastoma histologic subtypes, as defined by the World Health Organization (WHO) in WHO Classification of Tumours of the Central Nervous System.A retrospective review of pediatric patients with medulloblastoma between 1989 and 2011 identified 38 patients with both pretreatment MRI and original pathology slides. The mean and minimum tumor ADC values and conventional MRI features were compared among medulloblastoma histologic subtypes.The cohort of 38 patients included the following histologic subtypes: 24 classic medulloblastomas, nine large cell (LC) or anaplastic medulloblastomas, four desmoplastic medulloblastomas, and one medulloblastoma with extensive nodularity. The median age at diagnosis was 8 years (range, 1-21 years) and the median follow-up time was 33 months (range, 0-150 months). The mean ADC (× 10(-3) mm(2)/s) was lower in classic medulloblastoma (0.733 ± 0.046 [SD]) than in LC or anaplastic medulloblastoma (0.935 ± 0.127) (Mann-Whitney test, p = 0.004). Similarly, the minimum ADC was lower in classic medulloblastoma (average ± SD, 0.464 ± 0.056) than in LC or anaplastic medulloblastoma (0.630 ± 0.053) (p = 0.004). The MRI finding of focal cysts correlated with the classic and desmoplastic subtypes (Fisher exact test, p = 0.026). Leptomeningeal enhancement positively correlated with the LC or anaplastic medulloblastoma subtype and inversely correlated with the classic medulloblastoma and desmoplastic medulloblastoma subtypes (p = 0.04). Ring enhancement correlated with tumor necrosis (p = 0.022) and with the LC or anaplastic medulloblastoma histologic subtype (p < 0.001).The LC or anaplastic medulloblastoma subtype was associated with increased ADC and with ring enhancement, the latter of which correlated with tumor necrosis. These features could be considered in the evaluation of high-risk medulloblastoma subtypes.

    View details for DOI 10.2214/AJR.12.9249

    View details for Web of Science ID 000316622100045

    View details for PubMedID 23521467

  • Language and reading skills in school-aged children and adolescents born preterm are associated with white matter properties on diffusion tensor imaging NEUROPSYCHOLOGIA Feldman, H. M., Lee, E. S., Yeatman, J. D., Yeom, K. W. 2012; 50 (14): 3348-3362

    Abstract

    Children born preterm are at risk for deficits in language and reading. They are also at risk for injury to the white matter of the brain. The goal of this study was to determine whether performance in language and reading skills would be associated with white matter properties in children born preterm and full-term. Children born before 36 weeks gestation (n=23, mean±SD age 12.5±2.0 years, gestational age 28.7±2.5 weeks, birth weight 1184±431 g) and controls born after 37 weeks gestation (n=19, 13.1±2.1 years, 39.3±1.0 weeks, 3178±413 g) underwent a battery of language and reading tests. Diffusion tensor imaging (DTI) scans were processed using tract-based spatial statistics to generate a core white matter skeleton that was anatomically comparable across participants. Fractional anisotropy (FA) was the diffusion property used in analyses. In the full-term group, no regions of the whole FA-skeleton were associated with language and reading. In the preterm group, regions of the FA-skeleton were significantly associated with verbal IQ, linguistic processing speed, syntactic comprehension, and decoding. Combined, the regions formed a composite map of 22 clusters on 15 tracts in both hemispheres and in the ventral and dorsal streams. ROI analyses in the preterm group found that several of these regions also showed positive associations with receptive vocabulary, verbal memory, and reading comprehension. Some of the same regions showed weak negative correlations within the full-term group. Exploratory multiple regression in the preterm group found that specific white matter pathways were related to different aspects of language processing and reading, accounting for 27-44% of the variance. The findings suggest that higher performance in language and reading in a group of preterm but not full-term children is associated with higher fractional anisotropy of a bilateral and distributed white matter network.

    View details for DOI 10.1016/j.neuropsychologia.2012.10.014

    View details for Web of Science ID 000313142700020

    View details for PubMedID 23088817

  • Diffusion tensor imaging (DTI) with retrospective motion correction for large-scale pediatric imaging JOURNAL OF MAGNETIC RESONANCE IMAGING Holdsworth, S. J., Aksoy, M., Newbould, R. D., Yeom, K., Van, A. T., Ooi, M. B., Barnes, P. D., Bammer, R., Skare, S. 2012; 36 (4): 961-971

    Abstract

    To develop and implement a clinical DTI technique suitable for the pediatric setting that retrospectively corrects for large motion without the need for rescanning and/or reacquisition strategies, and to deliver high-quality DTI images (both in the presence and absence of large motion) using procedures that reduce image noise and artifacts.We implemented an in-house built generalized autocalibrating partially parallel acquisitions (GRAPPA)-accelerated diffusion tensor (DT) echo-planar imaging (EPI) sequence at 1.5T and 3T on 1600 patients between 1 month and 18 years old. To reconstruct the data, we developed a fully automated tailored reconstruction software that selects the best GRAPPA and ghost calibration weights; does 3D rigid-body realignment with importance weighting; and employs phase correction and complex averaging to lower Rician noise and reduce phase artifacts. For select cases we investigated the use of an additional volume rejection criterion and b-matrix correction for large motion.The DTI image reconstruction procedures developed here were extremely robust in correcting for motion, failing on only three subjects, while providing the radiologists high-quality data for routine evaluation.This work suggests that, apart from the rare instance of continuous motion throughout the scan, high-quality DTI brain data can be acquired using our proposed integrated sequence and reconstruction that uses a retrospective approach to motion correction. In addition, we demonstrate a substantial improvement in overall image quality by combining phase correction with complex averaging, which reduces the Rician noise that biases noisy data.

    View details for DOI 10.1002/jmri.23710

    View details for Web of Science ID 000308884300022

    View details for PubMedID 22689498

  • Application of diffusion tensor tractography in pediatric optic pathway glioma. Journal of neurosurgery. Pediatrics Lober, R. M., Guzman, R., Cheshier, S. H., Fredrick, D. R., Edwards, M. S., Yeom, K. W. 2012; 10 (4): 273-280

    Abstract

    Magnetic resonance imaging is commonly used in diagnosis and surveillance for optic pathway glioma (OPG). The authors investigated the role of diffusion tensor (DT) tractography in assessing the location of visual pathway fibers in the presence of tumor.Data in 10 children with OPG were acquired using a 3T MRI generalized autocalibrating parallel acquisitions DT-echo planar imaging sequence (25 isotropic directions with a b value of 1000 seconds/mm(2), slice thickness 3 mm). Fiber tractography was performed, with seed regions placed within the optic chiasm and bilateral nerves on the coronal plane, including the tumor and surrounding normal-appearing tissue. Tracking was performed with a curvature threshold of 30°.For prechiasmatic lesions, fibers either stopped abruptly at the tumor or traversed abnormally dilated nerve segments. Similar findings were seen with chiasmatic lesions, with an additional arrangement in which fibers diverged around the tumor. For each patient, DT tractography provided additional information about visual fiber arrangement in relation to the tumor that was not evident by using conventional MRI methods. Retrospective reconstruction of visual fibers in 1 patient with new postoperative hemianopia revealed an unexpected superior displacement of the optic tract that might have been helpful information had it been applied to preoperative planning or surgical navigation.Optic pathway DT tractography is feasible in patients with OPG and provides new information about the arrangement of visual fibers in relation to tumors that could be incorporated into surgical navigation for tumor biopsy or debulking procedures.

    View details for DOI 10.3171/2012.7.PEDS1270

    View details for PubMedID 22900485

  • White matter microstructure on diffusion tensor imaging is associated with conventional magnetic resonance imaging findings and cognitive function in adolescents born preterm DEVELOPMENTAL MEDICINE AND CHILD NEUROLOGY Feldman, H. M., Lee, E. S., Loe, I. M., Yeom, K. W., Grill-Spector, K., Luna, B. 2012; 54 (9): 809-814

    Abstract

    Diffusion tensor imaging (DTI) was used to evaluate white matter architecture after preterm birth. The goals were (1) to compare white matter microstructure in two cohorts of preterm- and term-born children; and (2) within preterm groups, to determine if sex, gestational age, birthweight, white matter injury score from conventional magnetic resonance imaging (MRI), or IQ was associated with DTI measures.Participants (n=121; 66 females, 55 males) were aged 9 to 16 years. They comprised 58 preterm children (site 1, n=25; and site 2, n=33) born at less than 36 weeks' gestation (mean 29.4 wks; birthweight 1289g) and 63 term children (site 1, n=40; site 2, n=23) born at more than 37 weeks' gestation. DTI was analyzed using tract-based spatial statistics. Diffusion measures were fractional anisotropy, axial, radial, and mean diffusivity.In no region of the white matter skeleton was fractional anisotropy lower in the preterm group at either site. Within the preterm groups, fractional anisotropy was significantly associated with white matter injury score, but not sex, gestational age, or birthweight. At site 1, fractional anisotropy was associated with IQ.DTI contributes to understanding individual differences after preterm birth but may not differentiate a relatively high-functioning group of preterm children from a matched group of term-born children.

    View details for DOI 10.1111/j.1469-8749.2012.04378.x

    View details for Web of Science ID 000307468700011

    View details for PubMedID 22803787

  • Oculomotor Assessments of Executive Function in Preterm Children JOURNAL OF PEDIATRICS Loe, I. M., Luna, B., Bledsoe, I. O., Yeom, K. W., Fritz, B. L., Feldman, H. M. 2012; 161 (3): 427-?

    Abstract

    To use objective, nonverbal oculomotor tasks to assess executive function and infer the neural basis of impairments in preterm children.Cross-sectional study of preterm children age 9-16 years (n = 69; mean gestational age 29 weeks) and full-term controls (n = 43). Tasks assessed sensorimotor function (reflexive prosaccades); resistance to peripheral distracters (fixation); response inhibition, response preparation, and execution of a voluntary saccade (antisaccades); and spatial working memory (memory-guided saccades). Group differences were analyzed using ANOVA. We used linear regression to analyze the contributions of age, sex, gestational age, and white matter category to task performance.Preterm children did not differ from controls on basic sensorimotor function, response inhibition, and working memory. Compared with controls, preterm children showed greater susceptibility to peripheral distracters (P = .008) and were slower to initiate an inhibitory response (P = .003). Regression models showed contributions of age and white matter category to task performance.Preterm children show intact basic sensorimotor function and demonstrate difficulties in processes underlying executive control, including increased distractibility and prolonged response preparation. These limitations may reflect specific neural abnormalities in fronto-subcortical executive control of behavior.

    View details for DOI 10.1016/j.jpeds.2012.02.037

    View details for Web of Science ID 000308141700015

    View details for PubMedID 22480696

  • High-Resolution MR Imaging of the Orbit in Patients with Retinoblastoma RADIOGRAPHICS Rauschecker, A. M., Patel, C. V., Yeom, K. W., Eisenhut, C. A., Gawande, R. S., O'Brien, J. M., Ebrahimi, K. B., Daldrup-Link, H. E. 2012; 32 (5): 1307-1326

    Abstract

    Retinoblastoma is the most common intraocular childhood malignancy, with a prevalence of one in 18,000 children younger than 5 years old in the United States. In 80% of patients, retinoblastoma is diagnosed before the age of three, and in 95% of patients, retinoblastoma is diagnosed before the age of five. Although reports exist of retinoblastoma in adults, onset beyond 6 years of age is rare. Broadly, retinoblastoma may be classified into two groups: sporadic and heritable. In either case, the origin of the tumor is a biallelic mutation in primitive neuroepithelial cells. Although their details vary, several staging schemes are used to describe the extent of retinoblastoma according to the following four general criteria: intraocular location, extraocular (extraorbital) location, central nervous system disease, and systemic metastases. In the past decade, substantial changes have taken place in terms of staging and monitoring treatment in patients with retinoblastoma. Diagnosis and treatment of retinoblastoma involve a multidisciplinary approach, for which imaging is a vital component. Increasing awareness and concerns about the effects of radiation in patients with retinoblastoma have led to a shift away from external-beam radiation therapy and toward chemotherapy and locoregional treatment, as well as the establishment of magnetic resonance imaging as the most important imaging modality for diagnosis, staging, and treatment monitoring.

    View details for DOI 10.1148/rg.325115176

    View details for Web of Science ID 000308632900010

    View details for PubMedID 22977020

  • Clinical Application of Readout-Segmented-Echo-Planar Imaging for Diffusion-Weighted Imaging in Pediatric Brain AMERICAN JOURNAL OF NEURORADIOLOGY Holdsworth, S. J., Yeom, K., Skare, S., Gentles, A. J., Barnes, P. D., Bammer, R. 2011; 32 (7): 1274-1279

    Abstract

    RS-EPI has been suggested as an alternative approach to EPI for high-resolution DWI with reduced distortions. To determine whether RS-EPI is a useful approach for routine clinical use, we implemented GRAPPA-accelerated RS-EPI DWI at our pediatric hospital and graded the images alongside standard accelerated (ASSET) EPI DWI used routinely for clinical studies.GRAPPA-accelerated RS-EPI DWIs and ASSET EPI DWIs were acquired on 35 pediatric patients using a 3T system in 35 pediatric patients. The images were graded alongside each other by using a 7-point Likert scale as follows: 1, nondiagnostic; 2, poor; 3, acceptable; 4, standard; 5, above average; 6, good; and 7, outstanding.The following were the average scores for EPI and RS-EPI, respectively: resolution, 3.5/5.2; distortion level, 2.9/6.0; SNR, 3.4/4.1; lesion conspicuity, 3.3/5.9; and diagnostic confidence, 3.2/6.0. Overall, the RS-EPI had significantly improved diagnostic confidence and more reliably defined the extent and structure of several lesions. Although ASSET EPI scans had better SNR per scanning time, the higher spatial resolution as well as reduced blurring and distortions on RS-EPI scans helped to better reveal important anatomic details at the cortical-subcortical levels, brain stem, temporal and inferior frontal lobes, skull base, sinonasal cavity, cranial nerves, and orbits.This work shows the importance of both resolution and decreased distortions in the clinics, which can be accomplished by a combination of parallel imaging and alternative k-space trajectories such as RS-EPI.

    View details for DOI 10.3174/ajnr.A2481

    View details for Web of Science ID 000294275100023

    View details for PubMedID 21596809

  • Effect of chronic red cell transfusion therapy on vasculopathies and silent infarcts in patients with sickle cell disease AMERICAN JOURNAL OF HEMATOLOGY Gyang, E., Yeom, K., Hoppe, C., Partap, S., Jeng, M. 2011; 86 (1): 104-106

    Abstract

    Regular, chronic red cell transfusions (CTX) have been shown to be effective prophylaxis against stroke in sickle cell disease (SCD) in those at risk. Because serial brain imaging is not routinely performed, little is known about the impact of CTX on silent infarcts (SI) and cerebral vascular pathology. Thus, we retrospectively evaluated the magnetic resonance imaging reports of a cohort of SCD patients who were prescribed CTX for either primary or secondary stroke prophylaxis. Seventeen patients with Hb SS were included (mean age 15 years, mean follow-up 4.3 years). Eight patients were on CTX for primary prophylaxis. New SI occurred in 17.6% of patients corresponding to an SI rate of 5.42 per 100 patient-years. Vasculopathy of the cerebral arteries was present in 65% of patients and progressed in 63% of these patients. Those who developed progressive vasculopathy were on CTX for an average of 8 years before lesions progressed. Patients on CTX for secondary prophylaxis had more SIs and evidence of progressive vascular disease than patients on CTX for primary prophylaxis. We conclude that adherence to CTX does not necessarily prevent SI or halt cerebral vasculopathy progression, especially in those with a history of overt stroke.

    View details for DOI 10.1002/ajh.21901

    View details for Web of Science ID 000285421300025

    View details for PubMedID 21117059

  • Loss of SMARCB1/INI1 expression in poorly differentiated chordomas ACTA NEUROPATHOLOGICA Mobley, B. C., McKenney, J. K., Bangs, C. D., Callahan, K., Yeom, K. W., Schneppenheim, R., Hayden, M. G., Cherry, A. M., Gokden, M., Edwards, M. S., Fisher, P. G., Vogel, H. 2010; 120 (6): 745-753

    Abstract

    Chordomas are malignant neoplasms that typically arise in the axial spine and primarily affect adults. When chordomas arise in pediatric patients they are more likely to display unusual histological features and aggressive behavior. We noted the absence of SMARCB1/INI1 expression by immunohistochemistry in an index case of poorly differentiated chordoma of the sacrum, leading us to further examine SMARCB1/INI1 expression as well as that of brachyury, a highly specific marker of notochordal differentiation, in 3 additional poorly differentiated chordomas of the clivus, 10 typical chordomas, and 8 atypical teratoid/rhabdoid tumors (AT/RTs). All 4 poorly differentiated chordomas and all AT/RTs lacked nuclear expression of SMARCB1/INI1, while the 10 typical chordomas maintained strong nuclear SMARCB1/INI1 immunoreactivity. All 10 typical and 4 poorly differentiated chordomas expressed brachyury; all 8 AT/RTs were brachyury immunonegative. Cytogenetic evaluation utilizing FISH probes near the SMARCB1/INI1 locus on chromosome 22q was also performed in all of the poorly differentiated chordomas in this series. Three of the four poorly differentiated chordomas had evidence for deletion of this region by FISH. Analysis of the SMARCB1/INI1 gene sequence was performed using formalin-fixed paraffin-embedded tissue in all cases and no point mutations were observed. In summary, all poorly differentiated chordomas in this series showed the absence of SMARCB1/INI1 expression, and were reliably distinguished from AT/RTs, clinically by their characteristic primary sites of origin and pathologically by strong nuclear brachyury expression. Our findings reveal a likely role for SMARCB1/INI1 in a subset of chordomas with aggressive features.

    View details for DOI 10.1007/s00401-010-0767-x

    View details for Web of Science ID 000284593200005

    View details for PubMedID 21057957

  • Langerhans cell histiocytosis in a 5-month-old presenting with biparietal masses Case report JOURNAL OF NEUROSURGERY-PEDIATRICS Pricola, K. L., Karamchandani, J., Vogel, H., Dahl, G. V., Yeom, K. W., Edwards, M. S., Guzman, R. 2010; 6 (4): 393-397

    Abstract

    Langerhans cell histiocytosis (LCH) is a rare proliferative disorder that occurs most commonly in the pediatric population as a result of pathological clonal proliferation of Langerhans cells with subsequent damage and destruction to surrounding tissue. Clinically, LCH presents in a variety of ways, which often results in prolonged time to diagnosis and subsequently poorer outcomes. In this case report, the authors describe an unusually early presentation of multisystem LCH in a patient at birth, which resulted in a 5-month delay to diagnosis and treatment. This patient presented both atypically young and with an uncommon initial manifestation of multisystem disease with multiple soft-tissue swellings rather than early skin involvement. Additionally, this patient had an unusual radiographic appearance with biparietal skull destruction on initial skull radiographs and biparietal soft-tissue lesions on CT resembling cephalohematoma at 3 months of age. The clinical and radiological evaluation, pathology, and treatment strategies are discussed, with particular attention paid to the importance of further workup of atypical nonresolving cephalohematomas to prevent disease progression and poorer outcomes.

    View details for DOI 10.3171/2010.7.PEDS10149

    View details for Web of Science ID 000282244400020

    View details for PubMedID 20887116

  • Cerebrovascular disease in childhood cancer survivors A Children's Oncology Group Report NEUROLOGY Morris, B., Partap, S., Yeom, K., Gibbs, I. C., Fisher, P. G., King, A. A. 2009; 73 (22): 1906-1913

    Abstract

    Curative therapy for childhood cancer has dramatically improved over past decades. Therapeutic radiation has been instrumental in this success. Unfortunately, irradiation is associated with untoward effects, including stroke and other cerebrovascular disease (CVD). The Children's Oncology Group (COG) has developed guidelines for screening survivors at risk for persistent or late sequelae of cancer therapy.This review summarizes the pathophysiology and relevant manifestations of radiation-induced CVD and outlines the specific patient groups at risk for early-onset stroke. The reader will be alerted to the availability of the COG recommendations for monitoring, and, when applicable, specific screening and treatment recommendations will be highlighted.A multidisciplinary task force critically reviewed the existing literature and scored the evidence to establish the current COG guidelines for monitoring health of survivors treated with head and neck irradiation.Previous head and neck exposure to therapeutic radiation is associated with latent CVD and increased risk for stroke in some patient groups. Common manifestations of radiation-induced CVD includes steno-occlusive disease, moyamoya, aneurysm, mineralizing microangiopathy, vascular malformations, and strokelike migraines.Risk for stroke is increased in survivors of pediatric CNS tumors, Hodgkin lymphoma, and acute lymphoblastic leukemia who received radiation to the brain and/or neck. As the population of survivors ages, vigilance for stroke and cerebrovascular disease needs to continue based on specific exposures during curative cancer therapy.

    View details for DOI 10.1212/WNL.0b013e3181c17ea8

    View details for Web of Science ID 000272205200015

    View details for PubMedID 19812380

  • Comparison of CT, PET, and PET/CT for Staging of Patients with Indolent Non-Hodgkin's Lymphoma MOLECULAR IMAGING AND BIOLOGY Fueger, B. J., Yeom, K., Czernin, J., Sayre, J. W., Phelps, M. E., Allen-Auerbach, M. S. 2009; 11 (4): 269-274

    Abstract

    The aim was to investigate the potential impact of positron emission tomography (PET)/computed tomography (CT) as compared to PET and CT on the staging of patients with indolent lymphoma.PET/CTs from 45 patients with indolent lymphoma undergoing staging or restaging were studied. Clinical follow-up, additional imaging, and histology served as the gold standard.PET/CT correctly diagnosed 92 nodal regions as positive for lymphomatous involvement and 458 as disease free vs 68 and 449 for PET and 64 and 459 for CT, respectively. The respective sensitivities, specificities, and accuracies were 99%, 100%, and 99.8% for PET/CT, 68%, 97.5%, and 92.2% for PET, and 70%, 100%, and 94.7% for CT. PET/CT performed significantly better than PET (p < 0.001 for sensitivity, specificity, and accuracy) and CT (p < 0.001 for sensitivity and accuracy). PET/CT also correctly identified significantly more extra-nodal lesions (22) than CT (14) and PET (nine).PET/CT provides significantly more accurate information compared to PET and CT for the staging and re-staging of patients with indolent lymphoma.

    View details for DOI 10.1007/s11307-009-0200-9

    View details for Web of Science ID 000266830700009

    View details for PubMedID 19326177

  • Severe Encephalomyelitis in an Immunocompetent Adult with Chromosomally Integrated Human Herpesvirus 6 and Clinical Response to Treatment with Foscarnet plus Ganciclovir CLINICAL INFECTIOUS DISEASES Troy, S. B., Blackburn, B. G., Yeom, K., Caulfield, A. K., Bhangoo, M. S., Montoya, J. G. 2008; 47 (12): E93-E96

    Abstract

    Human herpesvirus 6 has rarely been identified as a cause of encephalitis in immunocompetent adults. We describe a patient who had severe encephalomyelitis, hypoglycorrhachia, and human herpesvirus 6 identified in his cerebrospinal fluid and serum and who recovered after treatment with foscarnet and ganciclovir. Human herpesvirus 6 should be considered in immunocompetent patients with encephalitis.

    View details for DOI 10.1086/593315

    View details for Web of Science ID 000261163600035

    View details for PubMedID 18991511

  • Evaluation of suspected local recurrence in head and neck cancer: A comparison between PET and PET/CT for biopsy proven lesions EUROPEAN JOURNAL OF RADIOLOGY Halpern, B. S., Yeom, K., Fueger, B. J., Lufkin, R. B., Czernin, J., Allen-Auerbach, M. 2007; 62 (2): 199-204

    Abstract

    (18)F-FDG PET has a high accuracy for re-staging of head and neck cancer. The purpose of this study was to determine whether the diagnostic accuracy can be further improved with integrated PET/CT.Forty-nine patients with a mean age of 59+/-18 years were studied retrospectively. Histo-pathological verification was available either from complete tumor resection with or without lymph node dissection (n=27) or direct endoscopic biopsy (n=16) or ultrasound guided biopsy (n=6). Two reviewers blinded to the pathological findings read all PET images in consensus. An experienced radiologist was added for the interpretation of the PET/CT images.Tissue verification was available for 110 lesions in 49 patients. Sixty-seven lesions (61%) were biopsy positive and 43 (39%) were negative for malignant disease. PET and PET/CT showed an overall accuracy for cancer detection of 84 and 88% (p=0.06), respectively. Sensitivity and specificity for PET were 78 and 93% versus 84 (p=NS) and 95% (p=NS) with PET/CT. A patient-by-patient analysis yielded a sensitivity, specificity and accuracy for PET of 80, 56 and 76%, compared to 88% (p=NS), 78% (p=NS) and 86% (p=0.06) for PET/CT.The results of this study indicate that PET/CT does not significantly improve the detection of recurrence of head and neck cancer. However, a trend towards improved accuracy was observed (p=0.06).

    View details for DOI 10.1016/j.ejrad.2006.11.037

    View details for Web of Science ID 000246613700010

    View details for PubMedID 17223003

  • Standard PET/CT of the chest during shallow breathing is inadequate for comprehensive staging of lung cancer JOURNAL OF NUCLEAR MEDICINE Allen-Auerbach, M., Yeom, K., Park, J., Phelps, M., Czernin, J. 2006; 47 (2): 298-301

    Abstract

    The incidence of malignancy associated with subcentimeter pulmonary nodules (micronodules) in patients with malignant disease has been reported to be as high as 58%. Thus, detection of small lung nodules is important for appropriate staging of lung cancer. Because of respiratory motion, small parenchymal lung lesions can be missed on CT acquired during shallow breathing. Micronodules are usually too small to be characterized reliably with 18F-FDG PET. We aimed to determine the incidence of missed pulmonary micronodules on PET/CT studies acquired during shallow breathing.The study included 142 consecutive cancer patients (62 male and 80 female; mean age, 54 y) who underwent whole-body PET/CT during shallow breathing and breath-hold CT of the chest during maximal inspiration. CT findings were reviewed independently, and noncalcified nodules missed on the shallow-breathing scan were evaluated for size, location, and metabolic activity.Breath-hold chest CT detected an additional 125 parenchymal lung nodules (mean size, 3.4 +/- 1.6 mm; range, 1-9 mm) in 48 (34%) of the 142 patients. In these patients, 3 nodules, on average, were missed during shallow breathing. In 18 patients (13%), micronodules were identified exclusively on breath-hold images. None of the missed nodules demonstrated 18F-FDG uptake.Acquisition of standard PET/CT chest images during shallow breathing is inadequate for comprehensive cancer staging.

    View details for Web of Science ID 000235283500030

    View details for PubMedID 16455636

  • Computed tomographic scanning reduces cost and time of complete spine evaluation JOURNAL OF TRAUMA-INJURY INFECTION AND CRITICAL CARE Brandt, M. M., Wahl, W. L., Yeom, K., Kazerooni, E., Wang, S. C. 2004; 56 (5): 1022-1026

    Abstract

    We hypothesize that data collected from computed tomographic (CT) scans obtained for workup of chest or abdominal injuries provide data that are sufficient to screen for spinal fractures and will decrease the cost and time of spine evaluation after trauma.We reviewed plain radiographs from 55 selected trauma patients who also underwent CT scanning of the chest, abdomen, and pelvis. We also timed the radiologic workup of 50 consecutive trauma patients to determine the time required to complete radiographic spine evaluation.Forty-seven patients had thoracolumbar fractures. Thirteen patients were found to have 33 thoracolumbar spine fractures identified by CT scan but not plain radiography. Fractures were found on initial trauma CT scans of the chest, abdomen, and pelvis obtained to evaluate for visceral injuries. No injuries seen on plain film were missed on CT scan.We recommend using the data acquired from CT scans to evaluate the spine, supplementing them with additional studies only when needed for further clarification.

    View details for DOI 10.1097/01.TA.0000124304.68584.2C

    View details for Web of Science ID 000221703200022

    View details for PubMedID 15179241

  • Antibodies to HSP-70 in normal donors and autoimmune hearing loss patients LARYNGOSCOPE Yeom, K., Gray, J., Nair, T. S., Arts, H. A., Telian, S. A., Disher, M. J., El-Kashlan, H., Sataloff, R. T., Fisher, S. G., Carey, T. E. 2003; 113 (10): 1770-1776

    Abstract

    To evaluate serum antibody to heat shock protein (HSP) 70 as a marker for autoimmune sensorineural hearing loss (AISNHL).Sera from 20 patients with rapidly progressive sensorineural HL and 20 control volunteers without HL were tested for antibody reactivity against multiple HSP 70 substrates. Substrates included recombinant human HSP (rHuHSP) 72, purified bovine brain heat shock cognate (HSC) 73 and HSP 72, as well as heat-shocked and non-heat-shocked protein extracts from bovine kidney (MDBK) cells. All serum donors were previously tested for antibody to guinea pig inner ear supporting cells; 17 of 20 patients but none (0 of 20) of the controls were positive.Sera were tested using Western blots.Reactivity with rHuHSP 70 was observed in 16 patients and 17 controls. Similarly, 15 of 20 patients and 17 of 20 controls stained for both HSP 72 and HSC 73 from the bovine brain. When tested against the heat-shock-induced and control MDBK extracts, six patients and nine controls had greater reactivity with the induced HSP 72.The frequency of antibodies to HSP substrates did not differ in patients and controls. Prior studies reported that HSP 72 is the 68 kD antigen commonly detected by AISNHL sera. However, we show that HSP 72 antibodies are no more prevalent in patients than in normal controls. Thus, it is unlikely that the 68 kD protein is HSP 72. Therefore, HSPs are not appropriate substrates for serodiagnosis of AISNHL.

    View details for Web of Science ID 000185871500019

    View details for PubMedID 14520104

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