Abstract
BACKGROUND: Determining isocitrate dehydrogenase (IDH) mutation is crucial for glioma clinical management. MR diffusion-derived 'vessel density' (DDVD) offers non-invasive tissue perfusion evaluation within the tumor microenvironment. The study attempts to distinguish IDH genotypes of diffuse gliomas using DDVD in whole tumor parenchyma and its habitats. METHODS: This study enrolled 63 patients with diffuse gliomas (30 IDH-mutant and 33 IDH-wildtype) who underwent diffusion-weighted (DW) imaging at 3T. DDVD(b0b10) was the signal difference between the b = 0 and b = 10 s/mm(2) DW images. DDVD(b0b10_b10b20) is DDVD(b0b10) minus DDVD(b10b20). nDDVD was DDVD divided by signal intensity at b = 0 s/mm(2) DW image. Correlations between DDVD metrics/intravoxel incoherent motion (IVIM) imaging metrics (D and f) and IDH genotypes/Ki-67 status were studied. RESULTS: In tumor parenchyma, DDVD(b0b10_b10b20) and nDDVD(b0b10_b10b20) were lower, whereas D was higher in IDH-mutant gliomas [median (interquartile range): 12.76 (9.79-14.60); 15.14 (11.61-19.29); 1.31 (1.19-1.39)] compared to IDH-wildtype gliomas [14.48 (2.93-18.60), p = 0.008; 20.55 (15.89-24.02), p < 0.001; 1.16 (0.98-1.27), p = 0.003]. Habitat analysis improved the diagnostic performance for IDH genotyping, with the highest AUC of 0.823 found for the nDDVD(b0b10_b10b20) derived from the high DDVD(b0b10) value habitat. Diagnostic efficacy of the combined model of nDDVD(b0b10_b10b20) with D was superior to that of combined model of f with D. The habitat model incorporating age, sex, and Karnofsky Performance Status further significantly enhanced the diagnostic efficacy, with an AUC reaching 0.979. Additionally, DDVD and f showed a positive correlation with Ki-67, while D exhibited a negative correlation with Ki-67 (all p < 0.05). CONCLUSION: DDVD, as a novel biomarker of microvascular perfusion, effectively differentiates IDH genotypes in gliomas. The habitat analysis improves the diagnostic accuracy for IDH genotyping.