Transient early computed tomographic changes mimicking tumor progression after brain tumor irradiation.

Abstract

Transient computed tomographic (CT) changes occurring within 3 mo. after radiotherapy are described in 3 patients with cerebral gliomas. These changes consist of enlargement of an area of central necrosis, new tumor enhancement and increased tumor enhancement with adjacent low-density changes. Subsequent scans showed regression of these changes in all patients. These changes probably are the direct effect of radiation on tumor tissue and adjacent normal brain; possible mechanisms are discussed. These radiation-induced changes mimic tumor progression on CT. The importance of recognizing their transient nature is stressed.