CLINICAL-VALUE OF PROTON MAGNETIC-RESONANCE SPECTROSCOPY FOR DIFFERENTIATING RECURRENT OR RESIDUAL BRAIN-TUMOR FROM DELAYED CEREBRAL NECROSIS

Purpose: Delayed cerebral necrosis (DN) is a significant risk for brai n tumor patients treated with high-dose irradiation, Although differen tiating DN from tumor progression is an important clinical question, t he distinction cannot be made reliably by conventional imaging techniq ues, We undertook a pilot study to assess the ability of proton magnet ic resonance spectroscopy (H-1 MRS) to differentiate prospectively bet ween DN or recurrent/residual tumor in a series of children treated fo r primary brain tumors with high-dose irradiation, Methods and Materia ls: Twelve children (ages 3-16 years), who had clinical and MR imaging (MRI) changes that suggested a diagnosis of either DN or progressive/ recurrent brain tumor, underwent localized H-1 MRS prior to planned bi opsy, resection, or other confirmatory histological procedure, Prospec tive H-1 MRS interpretations were based on comparison of spectral peak patterns and quantitative peak area values from normalized spectra: a marked depression of the intracellular metabolite peaks from choline, creatine, and N-acetyl compounds was hypothesized to indicate DN, and median-to-high choline with easily visible creatine metabolite peaks was labeled progressive/recurrent tumor. Subsequent histological studi es identified the brain lesion as DN or recurrent/residual tumor, Resu lts: The patient series included five cases of DN and seven recurrent/ residual tumor cases, based on histology, The MRS criteria prospective ly identified five out of seven patients with active tumor, and four o ut of five patients with histologically proven DN correctly, Discrimin ant analysis suggested that the primary diagnostic information for dif ferentiating DN from tumor lay in the normalized MRS peak areas for ch oline and creatine compounds, Conclusions: Magnetic resonance spectros copy shows promising sensitivity and selectivity for differentiating D N from recurrent/progressive brain tumor, A novel diagnostic index bas ed on peak areas for choline and creatine compounds may provide a simp le discriminant for differentiating DN from recurrent or residual prim ary brain tumors. Copyright (C) 1996 Elsevier Science Inc.