Grading of CNS neoplasms using continuous arterial spin labeled perfusion MR imaging at 3 tesla

Purpose: To differentiate glioma grade based on blood flow measured using continuous arterial spin labeled (CASL) perfusion MRI, implemented at 3 Tesla for improved signal-to-noise ratio (SNR) and spin labeling effect. Materials and Methods: CASL perfusion images were obtained preoperatively in 26 patients with brain neoplasms (19 high-grade gliomas (HGGs; WHO grades 3 and 4) and seven low-grade gliomas (LGGs; WHO grades 1 and 2)). The mean and maximum tumor blood flow (TBF and TBFmax) were calculated in the neoplasm, including surrounding infiltrating tumor vs. edema. Measures normalized to global CBF (nTBF and nTBF(max)) were also obtained. Results: Normalized measures of TBFmax. provided the best distinction between HGG and LGG groups (Wilcoxon rank sum test, P = 0.01). Seventeen of 19 HGGs showed nTBF(max) > 1.0, and 15 of 19 showed nTBF(max) > 1.3. Four of seven LGGs showed nTBF(max) < 1.0, and six of seven showed nTBF(max) < 1.3. Absolute TBFmax also differed significantly between the HGG and LGG groups (P = 0.04). TBFmax in 11 of 17 HGGs was > 50 mL/ 100 g/min (mean +/- SD = 94.9 +/- 71.7 mL/100 g/min). All but one LGGs showed TBFmax <= 50 mL/ 100 g/min (mean +/- SD = 42.8 +/- 22.0 mL/ 100 g/min). Conclusion: CASL perfusion MRI provides a quantitative, noninvasive alternative to dynamic susceptibility contrast perfusion MR methods for evaluating gliomas.