NMR follow-up studies of CNS-tumors in infancy and childhood.

Sixteen children with brain tumors, fifteen of which were located in the posterior cranial fossa, were followed-up postoperatively with NMR. Four recurrences of medulloblastoma and one recurrence of an ependymoma were found. Three children showed signs of known therapeutic sequelae such as hygroma, atrophy and dilatation of the subarachnoid space. Previously unreported, boundary layer lesions were found in 8 children. The etiology of these lesions and their differentiation from tumor recurrence are discussed.