title: Proton magnetic resonance spectroscopy of late delayed radiation-induced injury of the brain.
abstract: We prospectively evaluated metabolite changes in late delayed radiation-induced injury to the temporal lobes on proton ((1)H) magnetic resonance spectroscopy (MRS) in 34 patients. Morphologically more severe injury on imaging tended to have lower N-acetyl aspartate (NAA)/creatine (Cr) and NAA/choline (Cho) ratios. A significantly higher Cho/Cr ratio was found in the most severe grade of cerebral necrosis, in which lactate might be present. The progressive decrease in NAA with increasing severity reflected neuronal loss at different stages of late delayed radiation-induced brain injury. The absence of Cho elevation in mild and moderate lesions did not suggest demyelination or glial hyperplasia as an etiologic mechanism of late delayed radiation-induced brain injury. The association of severe morphologic lesions with elevated lactate suggests ischemia as the underlying mechanism for severe lesions. (1)H MRS may provide metabolite information conducive to the understanding of the pathophysiology of late radiation-induced brain injury. J. Magn. Reson. Imaging 1999;10:130-137.
authors.affiliation: Department of Diagnostic Radiology and Organ Imaging, Prince of Wales Hospital, Chinese University of Hong Kong, Hong Kong, China. yl190chan@cuhk.edu.hk
authors.forename: Y L
authors.initials: YL
authors.lastname: Chan
authors.forename: D K
authors.initials: DK
authors.lastname: Yeung
authors.forename: S F
authors.initials: SF
authors.lastname: Leung
authors.forename: G
authors.initials: G
authors.lastname: Cao
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001930:Brain Injuries / Q000175:diagnosis / Q000209:etiology / Q000378:metabolism*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011832:Radiation Injuries / Q000150:complications / Q000175:diagnosis / Q000378:metabolism*; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D013702:Temporal Lobe / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects; D013997:Time Factors