Postoperative contrast enhancement in brain tumors and intracerebral hematomas: CT study

Postcontrast cerebral CT was performed sequentially on days 3, 7, and 14 after surgery in 34 patients [11 with gliomas; 6 with metastatic tumors, and 17 with intracerebral hematomas (ICH)]. The purpose of this study was to investigate the natural course and mechanisms of postoperative contrast enhancement (CE) of the brain around the removed lesions. Contrast enhancement was noted on days 3-14 in 10 patients in whom the gliomas were partially or subtotally removed. The intensity of CE appeared to increase with time. Among the six patients in whom the metastatic tumors were totally removed, four showed no CE until day 14 after surgery. Contrast enhancement appeared on day 3 in one and on day 14 in another. In 12 patients with ICH, which had been evacuated during the first 5 days after hemorrhage, CE was not noted on day 3 but began to appear on day 7, and intensified on day 14 after surgery. Contrast enhancement was demonstrated on day 3 in four of the five patients in whom the ICH was removed later than 10 days after the hemorrhage. No CE was observed on days 3 through 14 in the one patient in whom the hematoma capsule was totally removed. The present study suggests that CE noted on day 3 after removal of gliomas and metastatic tumors seems to be caused by extravasation of contrast medium within the residual tumor, which is devoid of blood-brain barrier. Contrast enhancement noted in ICH cases and intensifying CE noted in tumors 7 days after surgery seems likely to be caused by neovascularization in the postoperative brain.