ROLE OF MRI IN DIAGNOSIS OF POSTERIOR CRANIAL FOSSA MASSES

Abstract

The posterior cranial fossa posses unique diagnostic challenges. The area is small but it merits specific considerations as it contains important structures as well as vital centers. Magnetic Resonance Imaging has unveiled the contents of the posterior fossa, showing anatomical details, and playing an important role in detecting the underlying posterior fossa masses.

The aim of the present study was to evaluate the role of MRI in the diagnosis of posterior fossa masses regarding detection, accurate localization and extension and if possible, characterization.

This study included 76 patients, 39 males and 37 females. Their ages ranged from I .5 to 85 years. All cases were subjected to full clinical examination, Magnetic Resonance Imaging; 65 of them had also post contrast study. Computerized tomography (in 47 patients while the remaining patients had been examined by CT previous to reference), 5 patients were examined by abdominal US, 3 patients by plain chest X-ray and one patient by plain X-ray of the skull. Fundus examination was done for 2 patients.. CSF analysis & Erythrocyte sedimentation Rate (ESR) were done for 2 patients.

All data including site, size, relation to the adjacent structures, various signal intensities (T1 Wls, T2 Wls & PDWis), presence of hydrocephalus, and the signal void of calcification or blood vessels, in addition to the pattern of Gd-DTPA enhancement were collected and analysed to demonstrate the MR findings in different pathological groups as well as its value, superiority and limitation in comparison with CT. The MRI diagnosis was correlated with the surgical and pathological results in most of cases.