Added prognostic value of DCE blood volume imaging in patients with suspected recurrent or residual glioblastoma—A hybrid [18F]FET PET/MRI study

Abstract

Background MRI cerebral blood volume (CBV) measurements improves diagnosis of recurrent gliomas. The study investigated the prognostic value of dynamic contrast enhanced (DCE) CBV imaging in treated IDH wildtype glioblastoma when added to MRI or amino acid PET. Methods Hybrid [18F]FET PET/MRI with 2CXM (2-compartment exchange model) DCE from 86 adult patients with suspected recurrent or residual glioblastoma were retrospectively analysed. High CBV tumour volume (VOLCBV), and contrast enhancing (VOLCE) and [18F]FET active tumour (VOLFET) volumes were delineated. Absolute and fractional high CBV subvolumes within VOLCE and VOLFET were determined. Associations with overall survival (OS) were assessed by Cox analysis. Results Adjusted for MGMT status and steroid all total tumour volumes were individually associated with shorter OS. Adding VOLCBV to VOLCE, or VOLFET only the effect of VOLCBV was prognostic of OS (HR 1.327, p=0.042 and 1.352, p=0.011, respectively). High CBV subvolume within both VOLCE and VOLFET, were associated with shorter survival (HR 1.448, p=0.042 and 1.416, p=0011, respectively), and the low CBV subvolumes with longer survival (HR 0.504, p=0.002 and 0.365, p=0.001, respectively). The fraction of VOLCE and VOLFET with high CBV was a strong predictor of OS with shorter median OS in upper vs lower tertiles (8.3 vs 14.5 months and 7.1 vs 15.6 months, respectively, both p<0.001). Conclusions The high CBV tumour volume was a strong prognosticator of survival and allowed for separation of high and low risk subvolumes underlining the heterogeneous physiological environment represented in the contrast enhancing or metabolically active tumour volumes of treated glioblastoma.