Computed tomographic evaluation of therapeutically induced changes in primary and secondary brain tumors.

A prospective study was initiated to evaluate computed tomography as a method for monitoring therapeutically induced changes in brain tumors. Early postoperative scans may be misleading in the evaluation of residual tumor because of trauma to the blood-brain barrier during operation. The size of the dominant mass (17/25), enhancement (11/25), edema (11/25), and ventricular distortion (14/25) were decreased in many patients after radiation therapy. Occasional tumors increased in size during radiation therapy (3/25). Enlargement of the lateral ventricles developed in 9 of 25 patients. Computed tomography offers definite advantages over nuclide brain scans, angiography and other diagnostic studies for evaluating therapeutically induced changes in brain tumors.