CT and MRI aspects of supratentorial hemispheric tumors of childhood and adolescence.

The neuroradiological features of supratentorial hemispheric tumors (SHTs) were studied in 27 patients whose ages ranged from 11 months to 18 years. Astrocytomas constituted 10 of the 27 SHTs. On computed tomography low-grade astrocytomas were in most cases hypodense; after intravenous administration of contrast medium, pilocytic astrocytomas enhanced, whereas fibrillary astrocytomas did not. Gd-DPTA-enhanced magnetic resonance imaging was the most useful technique for the assessment of recurrences. Atypical imaging features were observed in one glioblastoma and in oligodendrogliomas (in half of the cases no calcifications were found). Gangliogliomas were surprisingly rather frequent in our series (5/27) and appeared in three cases as low-density, well-circumscribed lesions, not calcified and without edema and mass effect, while in two cases they had pronounced perifocal edema without clear demarcation. A rare desmoplastic infantile ganglioglioma was observed. The two meningiomas showed malignant behavior.