Cerebral microstructural changes in children suffering from hemolytic uremic syndrome.

To evaluate microstructural cerebral changes in children suffering from typical hemolytic uremic syndrome (HUS) based on apparent diffusion coefficient (ADC) maps. For 12 pediatric HUS patients (0.8 - 14.6 years of age) conventional magnetic resonance imaging (cMRI) at 1.5 T was retrospectively analyzed. ADC values were measured in 35 different brain regions and compared with age-related, previously published ADC reference values from a healthy pediatric control group. The HUS cohort was divided into 2 subgroups depending on clinical outcome. Subgroup A showed poor neurological outcome whereas subgroup B demonstrated improvement without lasting neurological deficits. Qualitative analysis revealed lesions by diffusion-weighted imaging (DWI) with hypointense correlate on the ADC map in basal ganglia and/or thalami and corresponding T2 hyperintensities in the majority of patients in Subgroup A (80%). Those in Subgroup B did not show qualitative DWI alterations with ADC correlate even when T2 hyperintense lesions were detected in basal ganglia and/or thalami. Quantitative analysis demonstrated abnormal ADC values in all HUS patients with a trend to a greater number of affected regions in Subgroup A compared to Subgroup B (16 versus 11 median number of regions respectively, p = 0.56).   Conclusion: Using DWI qualitative and quantitative differences were found between HUS patients showing poor neurological outcome and those without neurological deficits at discharge. While ADC values indicated more extensive cerebral changes than conventional qualitative findings, both may provide early prognostic indicators for neurological outcome in pediatric HUS patients. What is Known: • In patients with STEC-HUS and neurological symptoms, MRI may show hyperintense signals on T2 and altered diffusivity mostly affecting basal ganglia, thalami and periventricular white matter. What is New: • In such patients, early MRI including quantitative ADC measurements over different brain regions may allow for detection of signal alterations possibly reflecting microstructural changes in such patients.

Changes in brain microstructure during infancy and childhood using clinical feasible ADC-maps.

PURPOSE: The purpose of this study was to examine age-related changes in apparent diffusion coefficient (ADC) during infancy and childhood using routine MRI data. METHODS: A total of 112 investigations of patients aged 0 to 17.2 years showing a normal degree of myelination and no signal abnormalities on conventional MRI were retrospectively selected from our pool of pediatric MRI examinations at 1.5T. ADC maps based on our routinely included axial diffusion weighted sequence were created from the scanner. ADC values were measured in 35 different brain regions investigating normal age-related changes during the maturation of the human brain in infancy and childhood using clinical feasible sequences at 1.5T. RESULTS: The relationship between ADC values and age in infancy and childhood can be described as an exponential function. With increasing age, the ADC values decrease significantly in all brain regions, especially during the first 2 years of life. Except in the peritrigonal white matter, no significant differences were found between both hemispheres. Between 0 and 2 years of life, no significant gender differences were detected. CONCLUSIONS: Using ADC maps based on a routinely performed axial diffusion weighted sequence, it was possible first to describe the relationship between ADC values and age in infancy and childhood as exponential function in the whole brain and second to determine normative age-related ADC values in multiple brain regions.