NIMG-47. A HISTOGRAM-BASED, BACK-PROJECTION METHOD FOR TREATMENT RESPONSE ASSESSMENT IN GLIOBLASTOMA USING MULTI B-VALUE ADVANCED DIFFUSION MRI

METHODS We used least-square fitting to model four diffusion parameters from mono-, bi-, and stretch-exponential models, and performed a histogram analysis of all voxels located within ROIs dictated by the radiotherapy-planned clinical target volume. Histograms were generated for 10 patients with GBM at 2 time-points, before, and at 6 weeks of treatment with standard-of-care regimen (RT with concomitant and adjuvant temozolomide). For each parameter, percentile ranges corresponding to diffusion values with the greatest cumulative difference between the time points were identified, and associated voxels were back-projected onto their respective maps for spatial correspondence and comparison with standard radiological imaging. RESULTS & DISCUSSION: The greatest cumulative difference in diffusion parameters measured at baseline and at 6 weeks of treatment, spatially corresponded to voxels lying …