Apparent diffusion coefficient histogram analysis for prediction of prognosis in glioblastoma

Abstract

Background: To investigate the potential to predict prognosis of glioblastoma (GBM) patients by analysis of the broader and lower values in the lower distribution of apparent diffusion coefficient (ADC_L) (B&L-ADC_L) values in the ADC histogram.

Background: Presurgical publicly available diffusion-weighted images (DWI) and contrast-enhanced T1-weighted images from 76 GBM patients were analyzed. With applied 2-mixture normal distribution in the ADC histogram of enhanced lesions on T1-weighted images, the mean and width of ADC_L were analyzed. We dichotomized the lower mean of ADC_L (L-ADC_L) and the broader width of ADC_L (B-ADC_L) at their own average. B&L-ADC_L was defined as B-ADC_L with L-ADC_L. Progression-free survival (PFS) and overall survival (OS) were determined by using Cox proportional hazards analysis and the Kaplan-Meier method with the log-rank test. The difference between PFS and OS was calculated.

Results: Six (7.89%) patients had B&L-ADC_L values. B&L-ADC_L was strongly associated with poor PFS (hazard risk: 5.747; P=0.002) and OS (hazard risk: 3.331; P=0.018). There were significant differences in PFS (median, 77 vs. 302 days; P<0.001) and OS (median, 199 vs. 472 days; P=0.004) between the patents with and without B&L-ADC_L. There was no significant difference in the OS-PFS duration difference between the patients with (median, 79 days) and without B&L-ADC_L (median, 132 days) (P=0.348).

Conclusion: In this study, B&L-ADC_L from pretreatment ADC analysis predicted poor PFS. B&L-ADC_L may indicate higher cellularity and heterogeneity in GBM tumor tissue.

Keywords: Apparent diffusion coefficient; Glioblastoma; Histogram analysis; Progression-free survival.