SUPRATENTORIAL DIFFUSE ASTROCYTIC TUMORS - PROPOSAL OF AN MRI CLASSIFICATION

The aim of this study was to obtain an MRI severity-related classifica tion of diffuse astrocytic tumours able to integrate the histological data in the grading of such tumours. We studied presurgical MR images of 91 patients with a histological diagnosis of astrocytoma, anaplasti c astrocytoma and glioblastoma. A score ranging from 1 to 3 was assign ed by two independent readers to each of the following MR features: oe dema, mass effect, contrast enhancement, borders, signal homogeneity, necrosis, haemorrhage and flow void. Statistical analysis showed signi ficant differences in the mean MRI scores between the three histologic al grades. Contrast enhancement was found to be the best predictor of the histological grade followed by necrosis, signal homogeneity and bo rder scores. This classification represents a simple and reproducible means of carefully evaluating some macroscopic characteristics of thes e tumours. It could be used to integrate histological data especially in cases in which tissue sampling defects may affect the validity of t his examination.