Detection of local microvascular proliferation in IDH wild-type Glioblastoma using relative Cerebral Blood Volume.

Background: The microvascular proliferation (MVP) and the microvessel area (MVA) are known as diagnostic and prognostic biomarkers for glioblastoma; nevertheless, its measurement is costly, labor-intense, and invasive. MRI perfusion biomarkers such as such as relative cerebral blood volume (rCBV) may be a feasible alternative to predict MVP and estimate MVA. Purpose: This study aims to evaluate the detection capacity of MRI markers such as rCBV to detect local microvascular proliferation in IDH wild-type glioblastoma. In addition, we aim to analyze the association between rCBV values and the microvessel area in different regions of the tumor. Study type: Retrospective study. Population and subjects: Data from 71 tissue blocks belonging to 17 IDH wild-type glioblastoma patients were compiled from the Ivy GAP database. Field Strength/Sequence: 1.5T or 3.0T. Pregadolinium and postgadolinium-based contrast agent-enhanced T1-weighted MRI, T2- and FLAIR T2-weighted, and dynamic susceptibility contrast (DSC) T2* perfusion. Assessment: We analyzed preoperative MRIs to establish the association between the maximum and mean relative cerebral blood volume (rCBVmax and rCBVmean) with the presence/absence of microvascular proliferation and with the microvessel area for each tumor block. Statistical tests: Spearman9s correlation and Mann-Whitney test. Results: Significant positive correlations were found between rCBV and MVA in the analyzed tumor blocks (p<0.001). Additionally, significant differences in rCBV were found between blocks with MVP and blocks without MVP (p<0.0001). Data conclusion: The rCBV is shown as significantly different in those tissue blocks with microvascular proliferation from those blocks without it, and it is significantly correlated with microvessels area. This method allows a local detection and definition of MVP and MVA in different regions of the glioblastoma since the first diagnostic stage and in a non-invasive way.