SIGNAL INTENSITY OF BRAIN METASTASES ON T2-WEIGHTED IMAGES - SPECIFICITY FOR METASTASES FROM COLONIC CANCERS

In this report, we present and discuss the signal intensity of brain m etastases from colon cancer on both T1- and T2-weighted images. In fiv e of 6 cases, metastases were seen as markedly hypointense areas on T2 -weighted images. This finding should alert one to the possibility of a primary cancer of the colon. Some haemorrhagic metastases from other malignancies also showed marked hypointensity. They usually exhibited hyperintensity on T1-weighted images. A case of colon metastasis was also haemorrhagic, and in this case a hyperintense area was observed o n T1-weighted images. The marked hypointense area corresponded to peri pheral necrosis and probably some viable tumour. Aetiologically, such hypointensity was not induced by severe fibrosis, calcification or exc essive iron deposition.