Chen Hoffmann

Background: With the increasing use of magnetic resonance imaging (MRI) in children, radiologists frequently encounter incidental findings that may mimic pathology. One such underrecognized finding is T2-weighted hyperintensity in the superior extraconal orbital fat, which is occasionally mistaken for an infiltrative or neoplastic process. Objective: Our objective was to characterize the imaging appearance, prevalence, and clinical associations of superior extraconal orbital fat T2 hyperintensity in pediatric MRI. Materials and methods: We conducted a retrospective study of 143 pediatric patients (mean age 7.2±5.1 years) who underwent brain MRI with an orbit-specific protocol between 2015 and 2022. Patients were grouped based on the presence or absence of bilateral papilledema and whether imaging was performed under general anesthesia. Clinical data were extracted from the electronic medical records. Three neuroradiologists reviewed images for the presence of a hyperintense signal along the superior extraconal orbital fat. Interobserver agreement was calculated using Fleiss’ kappa. Univariate and multivariable logistic regression analyses were performed to assess associations with age, anesthesia, gender, and magnet strength. Results: Symmetric T2-hyperintense bands along the superior extraconal orbital fat were observed in 45.5% of patients. The finding was more common in younger children (4.4±3.9 years vs. 9.6±4.8 years; P P P =0.012), but no independent association with gender, anesthesia, or magnet strength. The hyperintensity was non-enhancing or only subtly enhancing. Clinical follow-up demonstrated no subsequent orbital or infiltrative pathology in the majority of patients, and most patients without documented follow-up underwent ambulatory MRI for evaluation of strabismus, which showed no evidence of infiltrative or other orbital disease. Conclusion: Superior extraconal orbital fat T2 hyperintensity is a relatively common, likely non-pathologic MRI finding in pediatric patients, particularly in younger children, and the apparent association with anesthesia likely reflects age-related confounding. Awareness of this benign appearance may help avoid diagnostic confusion and prevent unnecessary workup or intervention. Graphical

Background The early identification of intracranial aneurysms (IAs) enables risk stratification and the timely initiation of optimal management. This study aimed to identify patients with missed aneurysms for follow-up and possible treatment, and to evaluate the effectiveness of a commercial deep learning algorithm in retrospectively detecting missed IAs on CTA. Methods All consecutive head CTA studies of adult patients performed at a single referral center between February 18, 2020, and July 31, 2022, were retrospectively collected. A machine learning algorithm using natural language processing (NLP) classified radiology reports as positive or negative for aneurysms, and a convolutional neural network (CNN) algorithm analyzed the imaging data. Concordant results with the original reports were accepted as ground truth, while discordant cases were reviewed by three neuroradiologists, with majority voting determining the reference standard. Results A total of 2,615 head CTA studies were analyzed. the algorithm flagged 34 suspected missed aneurysms, with 67% (23/34) confirmed as true positives by at least two neuroradiologists. This improved detection by 20.9% (23/110) or 0.88% of all studies. Most missed aneurysms were small (≤ 3 mm). There were 4 false negatives, resulting in a sensitivity of 96.36%, specificity of 99.56%, positive predictive value of 90.6%, and negative predictive value of 99.84%. Conclusion This study highlights the potential of deep learning systems to detect missed intracranial aneurysms. Although the missed aneurysms in this cohort were predominantly small, follow-up or diagnostic digital subtraction angiography may still be warranted, depending on clinical characteristics and risk factors for aneurysm rupture.

Background and Purpose Single large-scale mitochondrial DNA deletion syndromes (SLSMDSs) are rare mitochondrial disorders that present a continuum of phenotypes, including Pearson syndrome, Kearns-Sayre syndrome, and progressive external ophthalmoplegia. Neuroimaging findings in SLSMDSs are underreported, and their role in diagnosis and disease monitoring remains inadequately defined. This study aims to characterize clinical features and analyze neuroimaging findings, including spectroscopy and diffusion imaging, in patients with SLSMDSs. Methods A retrospective review of 11 patients diagnosed with SLSMDSs at a tertiary referral center between 2013 and 2024 was conducted. Clinical, genetic, and neuroimaging data were analyzed. MRI scans were reviewed for abnormalities in various brain regions, including white matter, basal ganglia, thalami, corpus callosum, cerebellum, and brainstem. Results The cohort had a mean age of 8.3 years (63.6% female). MRI was normal in 4 patients. Among the remaining 7, symmetrical T2/FLAIR hyperintensities, with or without diffusion alterations, were frequently observed, involving the dorsal brainstem in 7/7 and the cerebellum in 6/7 of patients. Globi pallidi involvement was also present in 6 of 7 patients. MR basal ganglia spectroscopy demonstrated elevated lactate in 3 of 7 patients with available spectroscopy. Subcortical and deep white matter abnormalities were identified in 3 patients, sparing the periventricular regions. Imaging progression was noted in patients with serial studies (4 patients). Conclusions Neuroimaging in SLSMDSs typically demonstrates characteristic involvement of the dorsal brainstem, cerebellum, and basal ganglia, and may show diffusion alterations, a finding suggestive of metabolic injury. The observed pattern of subcortical white matter involvement with periventricular sparing may aid in differentiating this disorder from others. Normal imaging may be present in early or less severe disease. MRI, including diffusion imaging and spectroscopy, can support diagnosis and longitudinal monitoring.

An association between subtle changes in T2 white matter hyper-intense signals (WMHSs) detected in fetal brain magnetic resonance imaging (fbMRI) and congenital cytomegalovirus (CMV) infection has been established. The research aim of this study is to compare children with congenital CMV infection with neurodevelopment outcome and hearing deficit with and without WMHSs in a historic prospective case study cohort of 58 fbMRIs. Of these, in 37 cases, fbMRI was normal (normal group) and WMHSs were detected in 21 cases (WMHS group). The median infection week of the WMHS group was earlier than the normal fbMRI group (8 and 17 weeks of gestation, respectively). The proportion of infants treated with valganciclovir in the WMHS group was distinctly higher. Hearing impairment was not significantly different between the groups. VABS scores in all four domains were within normal range in both groups. The median score of the motor skills corrected for week of infection was better in the WMHS group. A multivariate analysis using the week of infection interaction variable of WMHS and valganciclovir treatment showed better motor score outcomes in the valganciclovir treatment group despite an earlier week of infection. WMHSs were not associated with neurodevelopmental outcome and hearing deficit. In our cohort, valganciclovir treatment may have a protective effect on fetuses with WMHSs by improving neurodevelopmental outcome.

An association between subtle changes in T2 white matter hyper-intense signals (WMHS) de-tected in fetal brain magnetic resonance imaging (fbMRI) and congenital cytomegalovirus (CMV) infection has been established. The research aim of this study is to compare children with congenital CMV infection with neurodevelopment outcome and hearing deficit with and with-out WMHS in a prospective historic cohort of 58 fbMRIs. Of these, WMHS was detected in 21. The median infection week of the WMHS group was earlier than the normal fbMRI group (8 and 17 weeks of gestation respectively). The proportion of infants treated with valganciclovir in the WMHS group was distinctly higher. Hearing impairment was not significantly different be-tween the groups. VABS scores in all 4 domains were within normal range in both groups. The median score of the motor skills corrected for week of infection was better in the WMHS group. A multivariate analysis using week of infection interaction variable of WMHS and valganciclo-vir treatment showed better motor score outcomes in the valganciclovir treatment group despite earlier week of infection. WMHS was not associated with neurodevelopmental outcome and hearing deficit. In our cohort valganciclovir treatment may have a protective effect on fetuses with WMHS by improving neurodevelopment outcome.

Traumatic brain injury (TBI) is known to have a substantial, though highly variable, impact on cognitive abilities. Due to the wide range of cognitive abilities among healthy individuals, an objective assessment of TBI-related cognitive loss requires an accurate measurement of premorbid cognitive performance. To address this problem, we recruited 50 adults who sustained a TBI and had performed a cognitive baseline assessment in adolescence as part of the aptitude tests mandated by the Israeli Defense Forces. This group was matched with non-injured controls (N=35). Pre and Post-injury cognitive assessments consisted of three domains, namely verbal abstraction, mathematical reasoning and non-verbal abstract reasoning (from the Wechsler adult intelligence scale-WAIS-III). The difference between post and pre-injury scores was calculated as a measure of domain-specific cognitive decline. Voxel-based regression was used to correlate cognitive decline with modulated gray matter probability maps controlling for age, Glasgow Coma Scale, and total intracranial volume. Using objectively assessed cognitive scores, we found that abstract reasoning declined in both moderate-severe and mild TBI patients, whereas verbal abstraction declined only in the moderate-severe group. Mathematical reasoning was not affected by TBI. In the TBI patients, non-verbal abstract reasoning post-pre injury change scores were negatively correlated with the volume of the insula. We conclude that access to premorbid neuropsychological data may have facilitated the discovery of the effects of mild TBI on abstract reasoning as well as a significant correlation between TBI-related decline in this cognitive domain and the volume of the bilateral insula, both of which had not been appreciated in the past.

Apparent diffusion coefficient (ADC) values in the developing fetus can be used in the diagnosis and prognosis of prenatal brain pathologies. To this end, we measured regional ADC in a relatively large cohort of normal fetal brains in utero. Diffusion-weighted imaging (DWI) was performed in 48 non-sedated 3rd trimester fetuses with normal structural MR imaging results. ADC was measured in white matter (frontal, parietal, temporal, and occipital lobes), basal ganglia, thalamus, pons, and cerebellum. Regional ADC values were compared by one-way ANOVA with gestational age as covariate. Regression analysis was used to examine gestational age-related changes in regional ADC. Four other cases of CMV infection were also examined. Median gestational age was 32 weeks (range, 26–33 weeks). There was a highly significant effect of region on ADC, whereby ADC values were highest in white matter, with significantly lower values in basal ganglia and cerebellum and the lowest values in thalamus and pons. ADC did not significantly change with gestational age in any of the regions tested. In the four cases with fetal CMV infection, ADC value was associated with a global decrease. ADC values in normal fetal brain are relatively stable during the third trimester, show consistent regional variation, and can make an important contribution to the early diagnosis and possibly prognosis of fetal brain pathologies.

Central nervous system involvement in AIDS patients can present at any stage of the disease. Brain lesions detected in imaging studies are usually treated empirically. A brain biopsy is indicated in the absence of clinical and radiologic improvement. In the present study, 16 AIDS patients underwent brain biopsy. We evaluated the diagnostic yield of the brain biopsy and the changes in the disease course. Sixteen consecutive AIDS patients (12 men, 4 women; mean age 40.8 years) underwent a brain biopsy at Sheba Medical Center between 1997 and 2009. A retrospective analysis was performed and the clinical outcome was recorded. Median CD4 count before biopsy was 62.6. Magnetic resonance images revealed multiple lesions in 12 patients and enhancing lesions in 12 patients. A total of 19 biopsies were performed in 16 patients. In the present series, the initial procedures provided a diagnostic yield of 81.25% (13 diagnostic cases from 16 procedures in 16 patients). Two of these patients underwent repeated biopsies that were eventually diagnostic . If repeated biopsies were taken into consideration, the diagnostic yield was 93.75% (15 diagnostic cases in 16 patients). The rate of hemorrhagic complications was 10.5% (2 hemorrhages in 19 procedures).Pathologic examination revealed parasitic and fungal infections in 6 patients (6/16; 38%), progressive multifocal leukoencephalopathy in 4 patients (4/16; 25%), AIDS encephalopathy in 4 patients (4/16; 25%), and lymphoma in 1 patient (1/16; 6%). One patient had a nonspecific inflammatory process (6%). The treatment modality was modified in 12 patients and led to clinical and radiologic improvement in 8 patients. Brain biopsy should be considered when empiric treatment of central nervous system lesions in AIDS patients fails. Biopsy is diagnostic in the majority of patients. The diagnosis allows for treatment modifications, which lead to clinical and radiologic improvement in some patients.

Misinterpretation of head computerized tomographic (CT) scans by radiology residents in the emergency department (ED) can result in delayed and even erroneous radiology diagnoses. Better knowledge of pitfalls and environmental factors may decrease the occurrence of these errors. To evaluate common misinterpretations of head CT scans by radiology residents in a level I trauma center ED. We studied 955 head CT scans of patients admitted to our ED from January 2010 to May 2011. They were reviewed separately by two senior neuroradiologists and graded as being unimportant (score of 1), important but not requiring emergent treatment (score of 2), and important requiring urgent treatment (score of 3). We recorded the time of day the examination was performed, the year of residency, the site, subsite and side of the lesion, the pathology, the anatomical mistake, false-positive findings, and the attending neuroradiologists' score. A total of 955 examinations were interpreted of which 398 had misinterpreted findings that were entered into the database, with the possibility of multiple errors per examination. The overall misinterpretation rate was 41%. The most commonly missed pathologies were chronic infarcts, hypodense lesions, and mucosal thickening in the paranasal sinuses. The most common sites for misdiagnosis were brain lobes, sinuses and deep brain structures. The highest percentage of misinterpretation occurred between 2.30 p.m. and 8 p.m. and the lowest between midnight and 8 a.m. (P < 0.05). The overall percentage of errors involving pathologies with a score of 3 by at least one of the neuroradiologists was 4.7%. Third-year residents had an overall higher error rate and first-year residents had significantly more false-positive misinterpretations compared to the other residents. The percentage of errors made by our residents in cases that required urgent treatment was comparable to the published data. We believe that the intense workload of radiology residents contributes to their misinterpretation of head CT findings.