Untreated Pediatric Primitive Neuroectodermal Tumor in Vivo: Quantitation of Taurine with MR Spectroscopy

Abstract

To retrospectively investigate whether quantitation of taurine (Tau) concentrations with proton magnetic resonance (MR) spectroscopy in vivo improves the differentiation of primitive neuroectodermal tumors (PNET) from other common brain tumors in pediatric patients. The institutional review board approved this review of clinical data; it was not necessary to obtain parental consent. This study was HIPAA compliant. Single-voxel proton spectroscopy was added to the preoperative MR imaging work-up of 29 patients (12 boys and 17 girls; mean age, 6.5 years +/- 3.5) with untreated brain tumors; 13 had PNETs, and 16 had other tumors. Absolute concentrations (measured in millimoles per kilogram of brain tissue) of metabolites of the proton spectrum were determined. Student t tests were used for statistical comparisons. Elevated absolute Tau concentration proved to be the most significant metabolite in the differentiation of PNETs from other tumors (6.09 mmol/kg +/- 2.24 vs 0.76 mmol/kg +/- 0.95, P < .001). PNETs also exhibited a higher ratio of Tau relative to choline (1.21 +/- 0.48 vs 0.28 +/- 0.39, P < .001), a higher ratio of Tau relative to creatine (1.28 +/- 0.44 vs 0.38 +/- 0.67, P < .001), a reduced a ratio of N-acetyl-aspartate relative to choline (0.20 +/- 0.20 vs 0.79 +/- 0.56, P < .001), and an increased choline concentration (5.30 mmol/kg +/- 1.64 vs 3.08 mmol/kg +/- 2.53, P < .05). Tau concentrations ranged from 2.62 to 11.15 mmol/kg in individual patients with a PNET. Single-voxel quantitative (1)H MR spectroscopy performed in patients with untreated pediatric brain tumors showed that the Tau concentration was significantly elevated in PNETs and was useful in the differentiation of PNETs from other tumors.