Multi-b-value diffusion stretched-exponential model parameters correlate with MIB-1 and CD34 expression in Glioma patients, an intraoperative MR-navigated, biopsy-based histopathologic study

BACKGROUND: To understand the pathological correlations of multi-b-value diffusion-weighted imaging (MDWI) stretched-exponential model (SEM) parameters of α and diffusion distribution index (DDC) in patients with glioma. SEM parameters, as promising biomarkers, played an important role in histologically grading gliomas. METHODS: Biopsy specimens were grouped as high-grade glioma (HGG) or low-grade glioma (LGG). MDWI-SEM parametric mapping of DDC(1500), α(1500) fitted by 15 b-values (0-1,500 sec/mm(2))and DDC(5000) and α(5000) fitted by 22 b-values (0-5,000 sec/mm(2)) were matched with pathological samples (stained by MIB-1 and CD34) by coregistered localized biopsies, and all SEM parameters were correlated with these pathological indices pMIB-1(percentage of MIB-1 expression positive rate) and CD34-MVD (CD34 expression positive microvascular density for each specimen). The two-tailed Spearman’s correlation was calculated for pathological indexes and SEM parameters, as well as WHO grades and SEM parameters. RESULTS: MDWI-derived α(1500) negatively correlated with CD34-MVD in both LGG (6 specimens) and HGG (26 specimens) (r=-0.437, P =0.012). MDWI-derived DDC(1500) and DDC(5000) negatively correlated with MIB-1 expression in all glioma patients (P<0.05). WHO grades negatively correlated with α(1500)(r=-0.485; P=0.005) and α(5000)(r=-0.395; P=0.025). CONCLUSIONS: SEM-derived DDC and α are significant in histologically grading gliomas, DDC may indicate the proliferative ability, and CD34 stained microvascular perfusion may be an important determinant of water diffusion inhomogeneity α in glioma.