Radial MR Fingerprinting for Accelerated High Resolution Quantitative Prostate MRI in Radiation Therapy
V Yu1*, E Subashi2, C Wu3, P Koken4, M Doneva5, R Otazo6, O Cohen7, (1) Memorial Sloan Kettering Cancer Center, New York, NY, (2) Memorial Sloan Kettering Cancer Center, New York, NY, (3) ,New York, NY, (4) Philips Medical Systems, ,,(5) Philips Medical Systems, ,,(6) Memorial Sloan Kettering Cancer Center, New York, NY, (7) Memorial Sloan Kettering Cancer Center,
Presentations
WE-D-TRACK 6-3 (Wednesday, 7/28/2021) 2:00 PM - 3:00 PM [Eastern Time (GMT-4)]
Purpose: magnetic resonance fingerprinting (MRF) provides simultaneous T1/T2 quantitative maps, allowing for longitudinal assessment of treatment response and disease progression. We examine the feasibility of a golden-angle radial MR fingerprinting for radiotherapy applications in prostate with a dedicated MRI simulator.
Methods: A 2D steady-state-free-precession(SSFP) MRF sequence with inversion preparation was used with golden angle radial trajectory readout. All scans were performed on a 3T Philips scanner equipped with a flat tabletop for MRI simulation. MR fingerprinting imaging parameters are as follows: in plane resolution 1.1x1.1 mm², slice thickness=5mm, [echo time(TE),repetition time(TR)] = [8.1ms,4ms], variable flip angle=0-60 degrees. The acquisition schedule contains 500 time points, and 3 golden-angle-radial-spokes per time point. The radial MRF sequence was tested with the NIST imaging phantom and the measured T1/T2 values were validated against the ground truth values. Prostate MRF images of a healthy volunteer subject were acquired. T1/T2 maps were calculated by dot product matching to the simulated MRF dictionary. Standard relaxation mapping methods, namely Variable-flip-angle(VFA) for T1 and Multi-single-echo-spin-echo(MSE) for T2, were performed for comparison. The prostate gland(P), peripheral zone(PZ) and transition zone(TZ) regions of interest were delineated, and the statistics and distribution of the quantitative mapping values were analyzed.
Results: T1/T2 quantitative maps were obtained covering the whole prostate gland in 3 minutes. The generated parameter maps on the NIST Phantom were in good agreement with expected T1/T2 values. All values from standard method or MRF were in agreement with published literature. The MRF-T1 average values for [P,PZ,TZ]=[1960ms,2171ms,1858ms]. Compared with VFA, MRF-T1 values were lower but achieve significantly lower standard deviations. The MRF T2 mean value for [P,PZ,TZ]=[52.7ms,68.4ms,47.4ms]. MSE-T2 resulted in higher average values and superior image quality at the cost of longer scan time.
Conclusion: feasibility of prostate radial MRF in the RT MRI simulation has been demonstrated.
Funding Support, Disclosures, and Conflict of Interest: This work was partially supported by the NIH/NCI Cancer Center Support Grant/Core Grant (P30 CA008748). PK and MD are employees of Philips Healthcare.
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