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On February 23, 2021, the pediatric neuroradiology community lost our beloved colleague, master clinician, and mentor, Dr Robert “Bob” A. Zimmerman. He died peacefully at home, amid family. Bob was born June 20, 1938, in Philadelphia, and he received his bachelor of arts degree in biology at

Diffusion tensor imaging (DTI) is an advanced MR imaging technique that provides noninvasive qualitative and quantitative information about the white matter microarchitecture. DTI and fiber tractography have been increasingly used in the past decade to investigate the microstructural neuroarchitecture of posterior fossa malformations. This article aimed to review DTI and fiber tractography findings in several posterior fossa malformations, and highlighted the added value of DTI and fiber tractography compared with conventional MR imaging. DTI and fiber tractography may provide information that is helpful to better understand the pathogenesis of selected posterior fossa malformations. In addition, DTI may elucidate the anatomic role of the cerebellum for neurocognitive functions in children with posterior fossa malformations and DTI scalars of the cerebellar, and brain stem white matter tracts may serve as a predictive biomarker for cognitive outcome. Finally, quantitative DTI analysis of cerebellar and brain stem white matter tracts may help to select candidates for therapeutic interventions and may enable monitoring of the therapy response. Learning Objective: To recognize the utility of diffusion tensor imaging and fiber tractography to study malformations of the posterior fossa and highlight the additional information that diffusion tensor imaging and fiber tractography may provide compared with conventional MR imaging sequences.

Head ultrasonography (HUS) is a reliable and easy to perform bedside imaging technique that can give valuable information about degree of brain injury/edema after perinatal asphyxia in term neonates. The goals of our study were to determine whether semiquantitative markers such as standardized white matter/gray matter (WM/GM) echogenicity ratio and resistive index (RI) value measured by HUS differs between asphyxiated term neonates and healthy controls. Thirty-one carefully selected term neonates who suffered from perinatal hypoxic–ischemic encephalopathy (HIE) were included in the study. The ratio of the WM/GM echogenicity of the cingulate gyrus was calculated. In addition, the RI value was measured in the anterior cerebral artery. US scalars were compared with 11 healthy neonates. WM/GM ratio is significantly increased and RI value significantly decreased in asphyxiated term neonates compared with healthy subjects. WM/GM ratio and RI value allows discriminating between asphyxiated neonates and healthy subjects. These US scalars may serve as valuable, easy to acquire semiquantitative bedside markers of brain HIE, when magnetic resonance imaging is unavailable or cannot be performed in the acute setting.

Susceptibility-weighted imaging (SWI) is a new high-resolution magnetic resonance imaging (MRI) tool that uses the paramagnetic susceptibility effects of deoxygenated blood to study the intracranial venous vasculature. We present SWI imaging findings in two children who suffered from acute arterial ischemia. Various patterns of normal/altered venous drainage could be identified. Our case study suggests that SWI assisted mapping of the regional changes of the cerebral venous drainage and correlation with diffusion weighted MRI may identify critically perfused brain at risk for infarct progression. Prospective studies are mandatory to further validate the value of SWI.

Vanishing white matter disease (VWM) is one of the most frequent inherited childhood white matter disorders. We present the brain and spinal cord disease progression on serial conventional magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) in a 4-year-old boy. Consecutive MRI examinations demonstrated a progression of the signal abnormalities in the cerebral white matter. Globally, apparent diffusion coefficient (ADC) values as well as axial and radial diffusivity increased over time, while fractional anisotropy (FA) values decreased. Involvement of the cervical posterior spinal tracts and mild global spinal cord atrophy was found. In conclusion, serial MRI and DTI studies may help to better understand the selective injury of the myelin and axons in VWM disease. These data may help in monitoring disease progression. Our data also show that complete neuroimaging work-up in VWM should also include the spinal cord.

Summary Objectives The goal of our study was to: determine the incidence of cerebellar lesions in a cohort of children and young adults with TSC, and analyze the magnetic resonance imaging (MRI) findings of cerebellar TSC lesions including their contrast behavior and diffusion characteristics. Material and Methods MRI studies of 27 TSC patients (mean age, 10.6 years) were evaluated for: cortical/subcortical tubers, white matter lesions, subependymal nodules, and giant cell astrocytomas. Patients with cerebellar involvement were further analyzed for the imaging and diffusion characteristics. ADC measurements of the cerebellar tubers were performed and compared with the contralateral normal appearing cerebellum. The clinical charts were revisited for symptoms suggesting cerebellar involvement. Results Cerebellar tubers were seen in 8/27 patients, cerebellar atrophy in 1/27 patients. Cerebellar tubers showed a pyramidal/wedge appearance with a broad base reaching the cortex. The majority of the cerebellar tubers (11/12, 92%) showed a “zebra-like” contrast enhancement. All cerebellar tubers had increased ADC values (mean ADC 1472 × 10 −6 mm 2 /s). None of the patients had “typical” cerebellar symptoms. Conclusion Thirty-three percent of TSC patients had cerebellar lesions, most of them being cerebellar tubers. Cerebellar tubers differ from supratentorial tubers both concerning shape and contrast behavior. The exact etiology of contrast enhancement remains unclear. Future studies have to determine the impact of cerebellar lesions on neurocognitive development.

Summary Background and purpose Patients with Sturge-Weber syndrome (SWS) may present with neurological symptoms or neurocognitive deficits that cannot always be explained by the supratentorial findings seen on conventional MRI. Purpose of our study was to determine (a) what percentage of children with SWS have simultaneous supra- and infratentorial involvement and (b) what kind of infratentorial lesions are seen. In addition, we used DWI data to measure the ADC-values of normal appearing white matter (NAWM) to rule out impaired or delayed white matter maturation. Material and methods Fifteen SWS patients who underwent MRI/DWI between January 2000 and August 2008 were studied. Images were retrospectively reviewed by two experienced pediatric neuroradiologists. ADC measurements of the NAWM were performed at multiple locations within the brain. ADC-values were compared with normative data and with 18 matched normal controls from our hospital. Results Infratentorial involvement was seen in six out of 15 patients (40%). Cerebellar lesions included leptomeningeal enhancement, atrophy and developmental venous anomaly. ADC-values were increased in the NAWM of the frontal, parietal and occipital lobes of both hemispheres and in the pons. The ADC-values of the cerebellar white matter were increased in six out of eight affected cerebellar lobes. Conclusion Infratentorial involvement of SWS is more frequently than previously thought. ADC analysis of the NAWM reveals impaired/altered white matter maturation distant from the area of leptomeningeal angiomatosis. This may explain neurocognitive deficits. ADC analysis of the NAWM may serve as biomarker of tissue injury and therefore guide treatment options.

We recently described the neuroimaging and clinical findings in 6 children with cerebellar clefts and proposed that they result from disruptive changes following prenatal cerebellar hemorrhage. We now report an additional series of 9 patients analyzing the clinical and neuroimaging findings. The clefts were located in the left cerebellar hemisphere in 5 cases, in the right in 3, and bilaterally in one child who had bilateral cerebellar hemorrhages as a preterm infant at 30 weeks gestation. In one patient born at 24 weeks of gestation a unilateral cerebellar hemorrhage has been found at the age of 4 months. Other findings included disordered alignment of the folia and fissures, an irregular gray/white matter junction, and abnormal arborization of the white matter in all cases. Supratentorial abnormalities were found in 4 cases. All but 2 patients were born at term. We confirm the distinct neuroimaging pattern of cerebellar clefts. Considering the documented fetal cerebellar hemorrhage in our first series, we postulate that cerebellar clefts usually represent residual disruptive changes after a prenatal cerebellar hemorrhage. Exceptionally, as now documented in 2 patients, cerebellar clefts can be found after neonatal cerebellar hemorrhages in preterm infants. The short-term outcome in these children was variable.

BACKGROUND AND PURPOSE: Hemispherectomy is a neurosurgical procedure to treat children with intractable seizures. Postsurgical improvement of cognitive and behavioral functions is observed in children after hemispherectomy suggesting plastic reorganization of the brain. Our aim was to characterize changes in DTI scalars in WM tracts of the remaining hemisphere in children after hemispherectomy, assess the associations between WM DTI scalars and age at the operation and time since the operation, and evaluate the changes in GM fractional anisotropy values in patients compared with controls. MATERIALS AND METHODS: Patients with congenital or acquired neurologic diseases who required hemispherectomy and had high-quality postsurgical DTI data available were included in this study. Atlas- and voxel-based analyses of DTI raw data of the remaining hemisphere were performed. Fractional anisotropy and mean, axial, and radial diffusivity values were calculated for WM and GM regions. A linear regression model was used for correlation between DTI scalars and age at and time since the operation. RESULTS: Nineteen patients after hemispherectomy and 21 controls were included. In patients, a decrease in fractional anisotropy and axial diffusivity values and an increase in mean diffusivity and radial diffusivity values of WM regions were observed compared with controls (P

BACKGROUND AND PURPOSE: Neurologic morbidity remains high in neonates with perinatal hypoxic-ischemic injury despite therapeutic hypothermia. DTI provides qualitative and quantitative information about the microstructure of the brain, and a near-infrared spectroscopy index can assess cerebrovascular autoregulation. We hypothesized that lower ADC values would correlate with worse autoregulatory function. MATERIALS AND METHODS: Thirty-one neonates with hypoxic-ischemic injury were enrolled. ADC scalars were measured in 27 neonates (age range, 4–15 days) in the anterior and posterior centrum semiovale, basal ganglia, thalamus, posterior limb of the internal capsule, pons, and middle cerebellar peduncle on MRI obtained after completion of therapeutic hypothermia. The blood pressure range of each neonate with the most robust autoregulation was identified by using a near-infrared spectroscopy index. Autoregulatory function was measured by blood pressure deviation below the range with optimal autoregulation. RESULTS: In neonates who had MRI on day of life ≥10, lower ADC scalars in the posterior centrum semiovale ( r = −0.87, P = .003, n = 9) and the posterior limb of the internal capsule ( r = −0.68, P = .04, n = 9) correlated with blood pressure deviation below the range with optimal autoregulation during hypothermia. Lower ADC scalars in the basal ganglia correlated with worse autoregulation during rewarming ( r = −0.71, P = .05, n = 8). CONCLUSIONS: Blood pressure deviation from the optimal autoregulatory range may be an early biomarker of injury in the posterior centrum semiovale, posterior limb of the internal capsule, and basal ganglia. Optimizing blood pressure to support autoregulation may decrease the risk of brain injury in cooled neonates with hypoxic-ischemic injury.

Cross-sectional imaging forms an important alternative and complimentary tool to endoscopy in aiding the clinician with diagnosis and management of pediatric inflammatory bowel disease (IBD). The purpose of the study was to evaluate the feasibility of an optimized Magnetic Resonance Enterography (MRE) protocol in the evaluation of patients with suspected IBD. 31 children (18 boys and 13 girls) were evaluated by a pediatric gastroenterologist prior to MRE and given a grading for clinical severity of disease. Imaging was then performed with oral contrast and a tailored protocol using fast T1/T2 weighted pulse sequences. Additionally, contrast and glucagon were administered intravenously. Imaging findings were then correlated with the clinical data. Excellent distension was achieved in the small bowel. The majority of the studies were of diagnostic quality with no motion artifacts. Imaging findings showed statistically significant correlation with disease activity. An optimized pediatric MRE protocol is feasible and correlates well with clinical disease activity. This in turn aids the clinician in the management of children with this chronic debilitating disease.

Aims: Macrocerebellum is a very rare finding and implies an abnormally large cerebellum. Only few patients with a syndromal or isolated macrocerebellum have been reported so far. We aim to evaluate the MRI spectrum, objectify the macrocerebellum by volumetric analysis, characterize neurological/dysmorphic features and cognitive outcome and report genetic analysis. Methods: All images were qualitatively evaluated for infra- and supratentorial abnormalities. A volumetric analysis was performed using MRI Studio software. Data about neurological and dysmorphic features, outcome and genetic analysis were collected from clinical history and follow-up examination. Results: 5 children were included (median age 2.5 years, range 1–3 years; 3 males, 2 females). The volumetric analysis in 3 patients confirmed the increased cerebellar size compared to age matched controls (in the 2 other patients the volumetric analysis could not be performed). The MRI evaluation showed that an enlargement of the cortical gray matter of the cerebellar hemispheres was mainly contributing to the macrocerebellum. Different additional infra- and supratentorial abnormalities were present in all patients. Muscular hypotonia, ocular movement disorders and impaired motor and cognitive development were found in all children. 3 of 5 patients suffered from epileptic seizures. The 5 children differed significantly in terms of dysmorphic features and involvement of extra-cerebral organs. Chromosomal anomalies were found in 2 patients (a deletion and a duplication on different chromosomes). Conclusion: Based on the literature and our study, all patients with a macrocerebellum have variable impairments in motor and cognitive development. However, the additional neuroimaging findings, dysmorphic features, involvement of extra-cerebral organs and genetic results are highly heterogeneous, suggesting that macrocerebellum is not a clinical and neuroimaging entity.

We report on the MRI findings of an anencephalic infant who survived 10 weeks postnatally. MRI showed absence of the cranial vault, all supratentorial structures, and the cerebellum. A brainstem primordium without pontine prominence was present. The brainstem was surrounded by the area cerebrovasculosa. The absence of a pontine prominence in an anencephalic infant without cerebellar tissue supports the hypothesis that absent pontine prominence is found in children with a prenatal loss of cerebellar tissue.

X-linked adreno-leukodystrophy (ALD) is a peroxisomal disorder affecting the white matter of the central nervous system and the adrenal cortex. It is caused by mutations in the ABCD1 gene encoding for a peroxisomal membrane protein. The absent genotype-phenotype correlation implies a contribution by environmental factors to explain the phenotypical heterogeneity. We report on a 4-year-old boy with a biochemically confirmed diagnosis of ALD after birth. At the age of 32 months, the additional diagnosis of a medulloblastoma was made. After treatment of the medulloblastoma, he developed active areas of demyelination representing the characteristic neuroimaging features of ALD. The clinical history of our patient supports the hypothesis that external factors, like neurosurgical intervention as part of medulloblastoma treatment, may accelerate or initiate cerebral ALD-related demyelination. A postsurgical inflammatory reaction may facilitate the inclusion of abnormal fatty acids in myelin. The opening of the blood-brain barrier following neurosurgery may enhance the recognition of previously sequestered antigens considered to play a role in ALD onset. Consequently, neurosurgical disruption of the BBB can precipitate the immune-mediated inflammatory process, which progressively destroys myelin in ALD patients. Tumor-related chemotherapy and/or radiotherapy may also play a contributing role. We suggest that X-ALD patients who undergo neurosurgical intervention need close follow-up imaging to identify active demyelination early.

MRI/DTI data are presented in a child with sensoneurinal hearing loss and swallowing disorder. MRI/DTI revealed hypoplastic 8th cranial nerves and an inferior pontine segmentation abnormality. Color-coded FA-maps revealed diminished/absent fiber tracts within the affected brainstem segment. This report may add another small puzzle piece to the ongoing research on brainstem malformations.

Sturge-Weber syndrome is a rare neurocutaneous disorder that typically presents with angiomas involving the face, ocular choroid and ipsilateral supratentorial leptomeninges. Posterior fossa involvement is extremely rare. We present two patients with simultaneous supra- and infratentorial involvement. Magnetic resonance imaging (MRI) and digital subtracted angiography (DSA) findings are discussed.

In contrast to malformations, cerebellar disruptions have attracted little interest in the literature. We draw attention for the first time to the hypothesis that cerebellar clefts are residual changes following a prenatal cerebellar insult, and represent disruptions. We reviewed the clinical records and MR findings of six patients with a cerebellar cleft, two of whom also had prenatal MRI at 24 weeks of gestation. The clefts were located in the left cerebellar hemisphere in five cases, in the right in one patient. Other typical findings included disorderly alignment of the cerebellar folia and fissures, irregular gray/white matter junction, and abnormal arborization of the white matter in all patients. The cerebellar cleft extended into the fourth ventricle in three cases, and in two children cystic cortical lesions were seen. Supratentorial schizencephaly was found in two patients. In two patients there was a documented fetal cerebellar hemorrhage at 24 weeks of gestation. We conclude that cerebellar clefts are residual changes resulting from a prenatal cerebellar insult and consequently represent disruptions rather than primary malformations. The supratentorial findings are also in agreement with an acquired lesion. The outcome in these children was variable, mainly depending of the presence of supratentorial lesions.

Objectives: To describe an unusual neurological course of a systemic vascular disease in two sisters of non-consanguineous parents. Methods: Case report. Results: The first child developed an acute hemiparesis and focal seizures at the age of 6 months during a febrile illness. MRI showed bilateral cortical-subcortical infarction within the vascular watershed areas. Subsequently the child had a stable neurological deficit. Her younger sister had the same encephalitis-like episode at the age of 4 months, with left sided cortical-subcortical ischemic lesions. Two months later she had left sided focal seizures. MRI showed a right-sided cortical enhancement, but MRA was normal. The neurological deficit was stable and she was seizure free. These episodes were interpreted as metabolic strokes, but work-up was normal and MELAS was excluded. In their teens both sisters were diagnosed with cardiomyopathy, pulmonary and systemic hypertension. Renal artery stenosis, pathologic pulmonary arteries and stenosis and rarefication of coronary arteries were found, aorta and retinal vessels were normal. Repeat cranial MRI and MRA showed multiple collaterals while the carotid and basilary arteries were virtually absent (moyamoya appearance). Conclusion: We suggest a hereditary systemic vasculopathy of unknown origin. Moyamoya syndrome rarely starts in the first months of life and extracranial vessel involvement is very rare. Coronary, renal and pulmonary artery stenosis have been described but not to this extent and combination. Normal MRA at the time of a first insult does not exclude underlying vascular disease. Signs of systemic vascular involvement should be sought and MRA repeated.

The significant and continuous development of the various neuroimaging techniques (especially of MR imaging) has revolutionized the analysis and understanding of multiple congenital brain anomalies over the last decade. The number and complexity of recognized congenital brain anomalies have steadily