Distinguishing atypical high-grade glioma from primary central nervous system lymphoma with diffusion MRI: neurite orientation dispersion and density imaging versus diffusion tensor imaging

This study aimed to compare the diagnostic efficiency between neurite orientation dispersion and density imaging (NODDI) and diffusion tensor imaging (DTI) in distinguishing atypical high-grade glioma (HGG) from primary central nervous system lymphoma (PCNSL). A total of 55 patients who underwent a multi-b-value diffusion-weighted imaging (DWI) and were pathologically diagnosed with atypical HGG (n = 30) or PCNSL (n = 25) were included in this study. Three regions of interest (ROIs) were manually outlined in tumor parenchyma, peritumoral edema and necrosis, respectively. Parameter values of NODDI [intracellular volume fraction (ICVF), isotropic volume fraction (ISOVF) and orientation dispersion index (ODI)] and DTI [mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD) and fractional anisotropy (FA)] from tumor parenchyma and peritumoral edema were compared between the two types of tumors using independent t-test, Welch’s t-test or Mann-Whitney U test. Diagnostic efficiencies were compared between NODDI and DTI within tumor parenchyma and peritumoral edema using DeLong’s test. P < 0.05 was considered statistically significant. The optimal cutoff points for the diagnostic parameters were set at the maximum Youden index. In tumor parenchyma, ODI displayed the highest area under the curve (AUC) of 0.961 among all NODDI parameters, and AD exhibited the highest AUC of 0.871 among all DTI parameters, the AUC of the former is significantly higher than that of the latter. In peritumoral edema, ISOVF displayed the highest AUC of 0.827 among all NODDI parameters, and AD exhibited the highest AUC of 0.756 among all DTI parameters, there was no significant difference between their AUCs. Parameter ODI of NODDI performed significantly better than other parameters produced by NODDI and DTI in the tumor parenchyma, and tumor parenchyma was proven to be the superior ROI option. NODDI can distinguish high grade glioma from primary central nervous system lymphoma. In both the tumor parenchyma and the peritumoral edema, NODDI exhibits excellent diagnostic performance. Parameter ODI of NODDI performed significantly better than other parameters produced by NODDI and DTI in the tumor parenchyma.