Diffusional kurtosis imaging for differentiating between high-grade glioma and primary central nervous system lymphoma.

Background The aim of this study was to assess the diagnostic accuracy of diffusion kurtosis magnetic resonance imaging parameters for differentiating high-grade gliomas (HGGs) from primary central nervous system lymphomas (PCNSLs). Methods Diffusion parameters, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (λ//), radial diffusivity (λ⊥); and kurtosis parameters, including mean kurtosis (MK), axial kurtosis (K//), and radial kurtosis (K⊥), were normalized to contralateral normal-appearing white matter (NAWMc) to decrease inter-individual and inter-regional changes across the entire brain, and then compared with the solid parts of 20 HGGs and 11 PCNSLs [median 95% confidence interval (CI), P < 0.004; 0.05/14], significance level, Kolmogorov-Smirnov test, Bonferroni correction]. Results FA, MD, λ//, and λ⊥ values were higher in HGGs than in PCNSLs, but not significantly [HGGs: 0.209 (95% CI, 0.134–0.338), 1.385 (95% CI, 1.05–1.710), 1.655 (95% CI, 1.30–2.060), 1.228 (95% CI, 0.932–1.480), respectively; PCNSLs: 0.143 (95% CI, 0.110–0.317), 1.070 (95% CI, 0.842–1.470), 1.260 (95% CI, 0.960–1.930), 1.010 (95% CI, 0.782–1.240)], respectively; P = 0.120, 0.010, 0.004, and 0.004, respectively). However, MK and K// were significantly higher in PCNSLs compared with HGGs [PCNSLs: 0.765 (95% CI, 0.697–0.890), 0.787 (95% CI, 0.615–1.030), respectively; HGGs: 0.531 (95% CI, 0.402–0.766), 0.532 (95% CI, 0.432–0.680], respectively; P = 0.001, 0.000, respectively); but not K⊥ [0.774 (95% CI, 0.681–0.899) for PCNSLs; 0.554 (95% CI, 0.389−0.954) for HGGs; P = 0.024]. Conclusion There were significant differences in kurtosis parameters (MK and K//) between HGGs and PCNSLs, while differences in diffusion parameters between them did not reach significance; hence, better separation was achieved with these parameters than with conventional diffusion imaging parameters. J. Magn. Reson. Imaging 2016;44:30–40.