Describing phenotypic subtypes of GBM in DWI imaging in relation to its genotypic subtypes

Thumbnail Image
Hasen, Mohammed Jr
Journal Title
Journal ISSN
Volume Title
Glioblastoma (GBM) is the most lethal primary brain tumour of the central nervous system, and has an unpredictable response to treatment with wide range of survival. There have been many attempts to identify factors that influence survival. We investigated the possible association between diffusion MRI, molecular signature, and survival of patients with GBM. This is a retrospective study conducted in Winnipeg (Health Sciences Center) for patients with GBMs from January 2015 to January 2018. In 93 patients, correlating normalized apparent diffusion coefficient (nADC) to time to death in days showed a Spearman’s rho correlation value of 0.244, indicating a weakly positive linear correlation. IDH mutation status in relation to nADC was found to be significant (mean difference of 0.38 and p-value of 0.015). The log-rank (Mantel–Cox) of nADC with cut-off point of 1.1725 was found to be significant (p-value of 0.046). The median survival was 11.5 months for nADC>1.1725 .vs 7.5 months for nADC<1.1725. The Cox regression multivariate analysis that included nADC (cut-off pint of 1.1725), age, nADC, IDH-mutation status, and extent of resection showed that age (p-value of 0.016) and nADC (p-value of 0.039) are statistically significant. Individuals with nADC <1.1725 were associated with an increased mortality hazard of 69% compared to individuals with nADC >1.1725 after adjusting for covariates of age, gender, and IDH mutation status. Individuals <70-year-old had a reduced mortality hazard of 47% compared to individuals >70-year-old old after adjusting for covariates of nADC, IDH mutation status, and extent of resection. In conclusion, nADC might have some value in identifying GBM patients with worse survival via IDH-mutation status.