NIMG-85. RADIATION DOSE IS ASSOCIATED WITH CHANGE IN MAGNETIC RESONANCE FINGERPRINTING PROPERTIES OF ANATOMICALLY DISTINCT REGIONS OF INTEREST IN GLIOBLASTOMA MULTIFORME PATIENTS

Abstract Magnetic Resonance Fingerprinting (MRF) is an investigational imaging technique that provides spatially-resolved quantification of tissue properties, in contrast to qualitatively weighted conventional MR imaging. Intentional sequential variation of acquisition parameters throughout the MRF acquisition produces a unique quantitative signal timecourse for each tissue, which generates a spatial “fingerprint” for individual voxels. This study applies MRF to quantitatively correlate radiation dose with MR signal intensity changes, specifically T1, T2, and M0 maps across regions of interest (ROIs) that are involved in cognitive speed and processing. Three patients who underwent radiation therapy for resected glioblastoma multiforme participated in this study. MRF scans were conducted at pre-radiotherapy (pre-RT), mid-radiotherapy (mid-RT), and post-radiotherapy (post-RT) timepoints. ROIs (bilateral hippocampi, amygdalae, dorsolateral prefrontal cortices, and corpus callosum) were contoured and radiation dose to the ROI contours at mid-RT and post-RT timepoints were obtained using MIM treatment planning software (MIM Software, Beachwood, OH). Spearman’s rank correlation test was conducted in MATLAB (MATLAB R2024a, Natick, MA) for mean radiation dose to ROIs against MRF T1 relaxation time, T2 relaxation time, and M0 proton density. Mean radiation dose exhibited statistically significant correlation with absolute changes from pre-RT to post-RT T1 relaxation time, T2 relaxation time, and M0 proton density values across the ROIs. Mid-RT scans showed intermediate changes, suggesting a progressive alteration in tissue characteristics with accumulating radiation dose. The hippocampus and amygdala received lower radiation doses than other ROIs and exhibited less pronounced changes in T1, T2, and M0 values. These results demonstrate a novel application of MRF in quantitative characterization of imaging changes in anatomically distinct ROIs. The correlation between radiation dose and absolute changes in MRF signal values from pre-RT to post-RT MRF scans reflect progressive changes as a result of radiation exposure.