Résumé
This cross sectional analytic study was carried out among the admitted patients of the department of Neurosurgery, Bangabandhu Sheikh Mujib Medical University, Dhaka during the period of 1st July 2002 to 31st December 2004. The age ranged from 2.5 years to 70 years. The size of all posterior fossa tumors at presentation were more than 3 cm and the mean size of posterior fossa tumor was 4.38 cm. 62% of posterior fossa mid-line tumors were mixed density in NECT (non-contrast CT).Regarding enhancement characteristics, mild-moderate enhancement and marked heterogeneous enhancement was equally distributed 46% followed by marked homogeneous enhancement only 08%.. The calcification was present only in 07 (14%) patients and most of them were ependymoma. Histopathologically, medulloblastoma was the common variety (32%). The CT scan diagnostic modality sensitivity, accuracy and positive predictive value were 100%, 84.78% and 84.78% respectively but in MRI diagnostic modality 100%, 91.30% and 91.30% respectively.