Evaluation of MRI score in the differentiation between glioblastoma multiforme and metastatic adenocarcinoma of the brain.

The authors statistically analyzed the MR configurations of 14 glioblastoma multiformes (GBMs) and 15 metastatic adenocarcinomas (MACs) of the brain in order to distinguish these two histological types on MR images. MR configurations were classified and scored upon the 9 criteria of heterogeneity, cyst or necrosis, haemorrhage, crossing of the midline by the tumour, oedema or mass effect, border definition, flow void sign, degree and heterogeneity after contrast enhancement. The mean value of GBMs was 1.47 +/- 0.22, and that of MACs was 0.91 +/- 0.37 (P < 0.001). GBMs had significantly higher values in five out of the nine criteria: border definition, heterogeneity, crossing of the midline of the tumour, flow void sign, and degree of the contrast enhancement (P < 0.001-0.05). Border definition was the best criterion for distinguishing two histological types. Six cases of MACs displayed hypo-intense lesions on T2 weighted images in contrast to GBMs which showed hyperintense lesions in all cases. In 4 out of the 6 MACs which were shown as hyperintensities on T2 weighted images, a hypo-intense peritumoural rim was noticed between the tumour parenchyma and the surrounding oedema. These data strongly suggest that GBMs and MACs can be distinguished on MR image by using MRI score.