MICROSCOPIC CORTICAL DYSPLASIA IN INFANTILE SPASMS - EVOLUTION OF WHITE-MATTER ABNORMALITIES

PURPOSE: To determine whether microscopic cortical lamination defects in patients with infantile spasms, not initially identifiable on MR, m ay be inferred from evolving changes in the adjacent white matter. MET HODS: Three infants between 3 and 6 months of age presented with infan tile spasms, Based on negative metabolic assessment and normal MR find ings, they were classified as cryptogenic. Despite therapy the childre n deteriorated with seizure recurrence and the advent of lateralizing clinical and neurophysiologic findings. MR studies were repeated and p ositron emission tomography was done. RESULTS: The second MR studies d emonstrated abnormalities of myelination, corresponding to localized c linical and neurophysiologic findings. Positron emission tomography fi ndings did not show a strong correlation; one was normal, one showed n o abnormality in the major area of MR abnormality, and one showed sign ificantly less abnormality than on MR, Two patients have undergone sur gery, both with good response. DISCUSSION: Subtle lamination defects m ay be identifiable on positron emission tomography but are usually not detectable on MR. White matter abnormality on MR images is usually at tributable to primary disease. We suggest that in certain cases progre ssive white matter changes may be induced as a secondary phenomenon by overlying microscopic cortical lamination defects. Serial MR imaging may be beneficial in children with infantile spasms in whom signs of l aterality evolve.