Search

Summary Background and purpose Susceptibility weighted imaging (SWI) allows the study of the intracranial venous vasculature based on the paramagnetic susceptibility effects of deoxygenated blood. Prominent hypointense draining veins have been revealed in ischemic brain tissue by SWI. The goal of our study was to evaluate whether a match or mismatch between territorial changes in the venous drainage of ischemic brain tissue, as identified by SWI and diffusion restriction, can show a ‘venous ischemic penumbra’. Materials and methods Eight children with a confirmed diagnosis of acute pediatric arterial ischemic stroke (PAIS) were included in this preliminary study. All had undergone an acute standard magnetic resonance imaging (MRI) study with diffusion-weighted imaging (DWI) and SWI sequences. SWI scans were semi-quantitatively evaluated for signal intensity and caliber of both the intramedullary and sulcal veins. In addition, SWI abnormalities were compared with DWI images for match/mismatch of signal alterations, and the acute MRI data were compared with follow-up scans. Results A total of 17 vascular territories showed infarction. SWI hypointensity in sulcal and intramedullary veins was found in 77% and 94% of the infarcted territories, respectively, while the caliber of the sulcal and intramedullary veins was increased in 64% and 88% of the infarcted areas, respectively. SWI/DWI match was observed in 88% of the vascular territories, whereas mismatch was noted in two; follow-up neuroimaging showed infarct progression into the mismatch areas. Conclusion Our study showed that, in children, high-quality SWI studies focused on venous drainage can provide important non-invasive data on critically perfused brain tissue at risk of infarct progression. SWI is therefore a valuable MR tool that can be added to the battery of neuroimaging techniques for acute PAIS.

Summary Objectives To evaluate the sensitivity and specificity of head ultrasound (HUS) in the detection of intracranial hemorrhage in premature neonates compared with brain MRI using susceptibility-weighted imaging (SWI). Material and methods Ultrasound (US) and MRI scans of the brain using SWI in premature neonates were retrospectively evaluated for grade I–III germinal matrix hemorrhage (GMH), periventricular hemorrhagic infarction (PVHI), intra-axial hemorrhage other than PVHI, extra-axial hemorrhage in each cerebral hemisphere and cerebellar hemorrhage in each cerebellar hemisphere. The impact of these hemorrhagic findings on short-term clinical management was also reviewed. Results Twelve neonates (mean age: 9.8 days; range: 3–23 days) with a mean gestational age of 32.8 weeks (range: 29.6–35.4 weeks) were included in the study. HUS had high sensitivity (100%) and specificity (93.3%) in detecting grade III GMH using SWI as a reference, but poor sensitivity (0%) in the detection of intraventricular hemorrhage with normal-sized ventricles (grade II GMH). US was not sensitive in detecting either small cerebellar or extra-axial hemorrhage. Conclusion HUS was highly sensitive and specific in the evaluation of grade III GMH, whereas SWI was superior to HUS in detecting small intra-axial or extra-axial hemorrhage, and had no impact on short-term management. Given the low cost, lack of radiation and advantages of bedside evaluation, HUS should continue to be the first line of imaging for brain injury in the evaluation of premature neonates with suspected intracranial hemorrhage. However, the usefulness of SWI for predicting long-term neurological outcomes has yet to be determined.

Summary Objective Normative apparent diffusion coefficient (ADC) and fractional anisotropy (FA) metrics of the brain have been published previously. However, no larger studies evaluated the normal evolution of ADC/FA metrics of the maturing paediatric spinal cord. Goal of this study is to evaluate the age-dependent evolution of the ADC/FA values of the developing/maturing normal cervical spinal cord (CSC). Patients and methods Forty-one subjects, aged less than 18 years with a negative spinal MRI study and no systemic central nervous disease, underwent diffusion tensor imaging (DTI) of the CSC. DTI metrics were measured in the centre of the CSC. Regression and ANCOVA analyses were performed to evaluate the association between ADC/FA values and age and its potential modification by sex. Results A linear model emerged as the best fit for our data. ADC showed a continuous decrease with age; FA showed a continuous increase with age. Conclusion The simultaneous age-related ADC decrease and FA increase likely reflect progressive maturation, myelination and fibre packing within the CSC similar to that observed in the brain. Collection of age-dependent normative DTI metrics may be helpful in the early identification and quantification of altered water diffusion in a variety of pathologies affecting the developing paediatric spinal cord.

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.

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.