Assessment of posterior fossa tumors in infants and children by means of computed tomography.

The attenuation profiles before and after contrast enhancement were examined in 18 infants and children with posterior fossa tumors: eight cerebellar astrocytomas, six medulloblastomas, and four brainstem tumors. The astrocytomas, with one exception, had characteristic patterns, and all could be distinguished from the medulloblastomas, which have a distinct pattern of their own. The brainstem tumors had varying appearances, and were entirely low-attenuating, high-attenuating or had a ring shadow after enhancement. The nature of a posterior fossa tumor in a pediatric patient can usually be predicted fairly satisfactorily from a computed tomogram.