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Updated: Feb 8, 2026
PET and MRI Guided Irradiation of a Glioblastoma Rat Model Using a Micro-irradiator
Published on: December 28, 2017
Combining Perfusion and High B-value Diffusion MRI to Inform Prognosis and Predict Failure Patterns in Glioblastoma
Daniel R Wahl1, Michelle M Kim1, Madhava P Aryal1
1Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan.
Purpose:
Advanced imaging modalities such as high b-value diffusion and dynamic contrast enhancement magnetic resonance imaging have the potential to improve the clinical management of glioblastoma by informing prognosis, predicting sites of progression, and guiding dose-escalated radiation to maximize tumor control and minimize toxicity.
Methods And Materials:
Fifty-two patients with de novo glioblastoma underwent magnetic resonance imaging before chemoradiation therapy. Enhanced tumor volumes (TVs), excluding the surgical cavity, hypercellularity (TVHCV) and increased cerebral blood volume (TVCBV) were defined using conventional gadolinium-enhanced T1-weighted images, high b-value (3000 s/mm2) diffusion-weighted images, and cerebral blood volume maps from T1-weighted dynamic contrast enhancement images, respectively. The image-phenotype TVs were analyzed for prediction of progression-free survival (Cox proportional hazard models), and sites of progression (pattern of failure tumor volume).
Results:
The median progression-free survival (PFS) of the cohort was 13 months. The TVCBV and TVHCV were spatially distinct, with a mean overlap of only 21%. Univariate analysis showed that increasing age, decreasing radiation dose, larger TVHCV, and larger overlap of TVHCV and TVCBV were significantly associated with inferior PFS. Multivariate analysis identified that TVHCV was the most adversely prognostic imaging-defined variable. Enhanced TVs, excluding the surgical cavity, and the union of TVHCV and TVCBV showed a high likelihood of containing the pattern of failure tumor volume, and the volume composed of the intersection of TVHCV and TVCBV had an especially high likelihood of progression.
Conclusions:
TVHCV and the overlap of TVHCV and TVCBV are prognostic for PFS. Combinations of gadolinium-enhanced TVs, TVCBV, and TVHCV could predict tumor progression locations better than could individual subvolumes. Radiation dose escalation to these subvolumes could be a promising therapeutic strategy.
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