Diagnostic and prognostic value of 18F-DOPA PET and 1H-MR spectroscopy in pediatric supratentorial infiltrative gliomas: A comparative study

Abstract

Background. 1H-MR spectroscopy (MRS) and 18F-dihydroxyphenylalanine (DOPA) PET are noninvasive imaging techniques able to assess metabolic features of brain tumors. The aim of this study was to compare diagnostic and prognostic information gathered by 18F-DOPA PET and 1H-MRS in children with supratentorial infiltrative gliomas or nonneoplastic brain lesions suspected to be gliomas. Methods. We retrospectively analyzed 27 pediatric patients with supratentorial infiltrative brain lesions on conventional MRI (21 gliomas and 6 nonneoplastic lesions) who underwent 18F-DOPA PET and 1H-MRS within 2 weeks of each other. 1H-MRS data (choline/N-acetylaspartate, choline-to-creatine ratios, and presence of lactate) and 18F-DOPA uptake parameters (lesion-tonormal tissue and lesion-to-striatum ratios) were compared and correlated with histology, WHO tumor grade, and patient outcome. Results. 1H-MRS and 18F-DOPA PET data were positively correlated. Sensitivity, specificity, and accuracy in distinguishing gliomas from nonneoplastic lesions were 95%, 83%, and 93% for 1H-MRS and 76%, 83%, and 78% for 18F-DOPA PET, respectively. No statistically significant differences were found between the 2 techniques (P.05). Significant differences regarding 18F-DOPA uptake and 1H-MRS ratios were found between low-grade and high-grade gliomas (P =.001 and P =.04, respectively). On multivariate analysis, 18F-DOPA uptake independently correlated with progression-free survival (P =.05) and overall survival (P 04), whereas 1H-MRS did not show significant association with outcome. Co nc lu si on s. 1H-MRS and 18F-DOPA PET provide useful complementary information for evaluating the metabolism of pediatric brain lesions. 1H-MRS represents the method of first choice for differentiating brain gliomas from nonneoplastic lesions.18F-DOPA uptake better discriminates low-grade from high-grade gliomas and is an independent predictor of outcome.