MR imaging of tuberous sclerosis in neonates and young infants.

BACKGROUND AND PURPOSE The MR imaging appearance of intracranial manifestations in tuberous sclerosis varies with age. The aim of this study was to specify MR characteristics in a coherent group of neonates and infants in order to distinguish them from the mature pattern. METHODS The MR studies of seven patients under 3 months old were reviewed retrospectively. Imaging appearance, number, and distribution of tubers, white matter anomalies, subependymal nodules, and subependymal giant cell astrocytomas were analyzed. RESULTS All patients had more white matter anomalies, subependymal nodules, subependymal giant cell astrocytomas, transmantle dysplasias, and left-hemispheric and temporal lesions, but less cortical tubers than did older patients in previous series. The lesions were easy to detect as hyperintense foci on T1-weighted images. Visibility as hypointensities on T2-weighted images was comparatively poor. CONCLUSION The nodular subependymal and linear parenchymal tuberous sclerosis lesions in infants under 3 months old are hyperintense on T1-weighted images and hypointense on T2-weighted images as opposed to the reverse pattern of signal intensity in older persons. The scarce myelination helps to identify white matter anomalies, which become less visible as myelination progresses. Conversely, purely intracortical tubers are more difficult to diagnose in infants. Because the overall number and conspicuity of all other lesions in our series were greater than in previous series with older subjects, our findings indicate that infant age does not compromise, but facilitates, the correct MR diagnosis of tuberous sclerosis. Therefore, if tuberous sclerosis is clinically suspected within the first 3 months of life, imaging should not be delayed.