LATE RADIATION CHANGE IN THE CNS - MR-IMAGING FOLLOWING GADOLINIUM ENHANCEMENT

Magnetic resonance imaging is the best imaging technique for the detec tion of radiotherapy-induced changes in the central nervous system but there are few studies detailing the MRI appearances of radiation effe cts following enhancement with intravenous gadolinium. In this paper, gadolinium enhanced MR imaging findings were reviewed in seven patient s with evidence of late radiation injury following radiotherapy for pr imary head and neck tumours. On T1-weighted enhanced sequences, abnorm al focal areas were present in the anterior temporal lobes and antero- inferior aspects of the frontal lobes, These lesions were well defined and enhanced intensely following intravenous gadolinium. They were pr esent in the white matter in five patients and involved both grey and white matter in two patients. Cystic components were present in larger lesions in three patients and mass effect was present around the enha ncing lesions in four patients. All abnormalities occurred within the radiation treatment portals and corresponded to the distribution of in creased signal intensity changes in the brain on T2-weighted images. L ate radiation-induced injury should be considered in the differential diagnosis of any intensely enhancing lesion occurring within irradiate d brain tissue.