(Tuesday, 7/31/2018) 1:45 PM - 3:45 PM
Room: Karl Dean Ballroom C
Purpose: To assess feasibility of a 3D Magnetic Resonance Fingerprinting (MRF) technique with whole-brain coverage for radiotherapy and evaluate its performance in terms of quantitative tissue characterization and sensitivity to field inhomogeneity and subject motion.
Methods: A newly developed 3D-MRF was tested for its applications in radiotherapy. It provides whole-brain quantitative T1 and T2 mapping in ~10 min (similar to the total acquisition time of current T1- and T2-weighted MRI) with a spatial resolution of 1.2×1.2×3mm3. Performance of 3D-MRF was examined in vivo with four healthy volunteers at 3T. A 3D printed MRI phantom was designed to evaluate the robustness of 3D-MRF towards field inhomogeneity induced geometric distortions. The results were compared to conventional MPRAGE T1-weighted images and the gold standard geometry acquired using CT. Finally, the sensitivity of 3D-MRF to motion was examined by asking one subject to intentionally move during 10% of acquisition and results were compared to MPRAGE acquired with similar amount of motion.
Results: High-quality quantitative T1 and T2 maps were successfully obtained from all four subjects and values in white matter, gray matter and cerebrospinal fluid are consistent with literature results obtained at the same field strength. Both phantom experiments and in vivo results demonstrate that compared to the conventional MPRAGE sequence, the proposed 3D-MRF is more robust to subject motion and geometrical distortions associated with susceptibility and field inhomogeneity. The Dice coefficients between contours of MRI phantom on CT and on quantitative T1 and that from MPRAGE were 0.80 and 0.72 respectively.
Conclusion: 3D-MRF demonstrates improved robustness to susceptibility and within-scan motion. With quantitative T1 and T2 measures that are independent of scanning techniques and machines, 3D-MRF will have great potential to provide more accurate tissue characterization, longitudinal treatment monitoring, and MRI-only treatment planning for radiation therapy as compared to conventional contrast-weighted imaging methods.
Keywords
MRI, Radiation Therapy, Quantitative Imaging
Taxonomy
Not Applicable / None Entered.
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