First demonstration of resting-state functional MRI on a 1.5T MR-Linac to assess functional connectivity in glioblastoma patients

Motivation: Glioblastomas are infiltrative brain tumors linked to neuro-cognitive impairments. Monitoring functional connectivity with MRI-linear accelerator (MR-Linac) during radiotherapy could guide treatment adaptation. However, the feasibility of monitoring changes in resting-state functional MRI (rs-fMRI) on MR-Linacs has yet to be validated. Goal(s): We sought to determine the repeatability of rs-fMRI on a 1.5T MR-Linac during radiotherapy in glioblastoma patients. Approach: We acquired weekly rs-fMRI in 25 glioblastoma patients during radiotherapy and evaluated the repeatability of functional connectivity across sessions. Results: We provided the first demonstration of MR-Linac rs-fMRI. Functional connectivity patterns were patient-specific, with high within-patient repeatability. Impact: We showed that frequent resting-state functional imaging on MRI-linear accelerators is feasible, with high within-patient and low across-patient session similarity. These findings suggest a potential for tracking individual functional network changes during radiotherapy to guide treatment adaptation in glioblastoma patients.