Malignant gliomas: MR imaging spectrum of radiation therapy- and chemotherapy-induced necrosis of the brain after treatment.
OBJECTIVE
To describe both the common and less frequently encountered magnetic resonance (MR) imaging features of radiation therapy- and chemotherapy-induced brain injury, with particular emphasis on radiation necrosis.


METHODS
A cohort of 148 adult patients underwent surgical resection of malignant brain (glial) tumors and were subsequently entered into a research protocol that consisted of accelerated radiation therapy with carboplatin followed by chemotherapy with procarbazine, lomustine, and vincristine. Patients typically underwent sequential MR imaging at 6-8-week intervals during the 1st year and at 3-6-month intervals during subsequent years. In all patients, histopathologic confirmation of lesion composition was performed by board-certified neuropathologists.


RESULTS
The patients exhibited different types of MR imaging-detected abnormalities of the brain: pure radiation necrosis in 20 patients, a mixture of predominantly radiation necrosis with limited recurrent and/or residual tumor (less than 20% of resected tissue) in 16 patients, radiation necrosis of the cranial nerves and/or their pathways in two patients, radiation-induced enhancement of the white matter in 52 patients, and radiation-induced enhancement of the cortex in nine patients.


CONCLUSIONS
The frequent diagnostic dilemma of recurrent neoplasm versus radiation necrosis is addressed in this study through a description of the varying spatial and temporal patterns of radiation necrosis at MR imaging.
Kumar
A J
AJ
Division of Diagnostic Imaging, University of Texas M.D. Anderson Cancer Center, Box 57, Houston, TX 77030, USA. akumar@mdanderson.org
Leeds
N E
NE
Fuller
G N
GN
Van Tassel
P
P
Maor
M H
MH
Sawaya
R E
RE
Levin
V A
VA
D000293:Adolescent; D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000009:adverse effects*; D001921:Brain / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects; D001932:Brain Neoplasms / Q000175:diagnosis / Q000628:therapy*; D003937:Diagnosis, Differential; D005260:Female; D005910:Glioma / Q000175:diagnosis / Q000628:therapy*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D009364:Neoplasm Recurrence, Local; D011832:Radiation Injuries / Q000175:diagnosis*
D000970:Antineoplastic Agents