Assessment of the pathological grade of astrocytic gliomas using an MRI score.

To evaluate the usefulness of an MRI score for identifying tumour tissue characteristics, 41 histologically verified supratentorial astrocytic gliomas, including 13 low-grade astrocytomas (LGA) 14 anaplastic astrocytomas (AA) and 14 glioblastoma multiformes (GBM), were examined with a 0.5T superconductive MR imager. Nine MRI criteria were used: heterogeneity (HET), cyst formation or necrosis (CN), haemorrhage (HEM), crossing the midline (CM), oedema or mass effect (EM), border definition (BD), flow void (FV), degree (CE-D) and heterogeneity (CE-HET) of contrast enhancement; Gd-enhanced T1-weighted images were obtained in 32 cases (10 LGA, 10 AA, and 12 GBM). Each of the criteria was scored and analysed statistically. The mean values of LGA, AA and GBM were 0.45 +/- 0.31, 1.18 +/- 0.20, and 1.47 +/- 0.22, respectively. The MRI score increased with the pathological grades (P < 0.01-0.001). LGA had significantly lower values than AA in five (HET, CN, EM, BD, CE-D) of the nine criteria (55.6%) and lower values than GBM in all except HEM (88.9%). Three criteria (33.3%): HET, CN, and FV were significantly higher in GBM than AA. CE-D, HET, EM, CN, and CE-HET proved to be related to the pathological grade by a multiple regression analysis (P < 0.001).