Ensuring both velocity and spatial responses robust to B0/B1+ field inhomogeneities for velocity-selective arterial spin labeling through dynamic phase-cycling
- 주제(키워드) arterial spin labeling , B1+ field inhomogeneity , B0 field inhomogeneity , cerebral blood flow , velocity-selective inversion
- 관리정보기술 faculty
- 등재 SCIE, SCOPUS
- 발행기관 John Wiley and Sons Inc
- 발행년도 2021
- URI http://www.dcollection.net/handler/ewha/000000175644
- 본문언어 영어
- Published As http://dx.doi.org/10.1002/mrm.28622
- 저작권 이화여자대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Purpose: To evaluate both velocity and spatial responses of velocity-selective arterial spin labeling (VS-ASL), using velocity-insensitive and velocity-compensated waveforms for control modules, as well as a novel dynamic phase-cycling approach, at different B0/ (Formula presented.) field inhomogeneities. Methods: In the presence of imperfect refocusing, the mechanism of phase-cycling the refocusing pulses through four dynamics was first theoretically analyzed with the conventional velocity-selective saturation (VSS) pulse train. Numerical simulations were then deployed to compare the performance of the Fourier-transform based velocity-selective inversion (FT-VSI) with these three different schemes in terms of both velocity and spatial responses under various B0/ (Formula presented.) conditions. Phantom and human brain scans were performed to evaluate the three methods at (Formula presented.) scales of 0.8, 1.0, and 1.2. Results: The simulations of FT-VSI showed that, under nonuniform B0/ (Formula presented.) conditions, the scheme with velocity-insensitive control was susceptible to DC bias of the static spins as systematic error, while the scheme with velocity-compensated control had deteriorated velocity-selective labeling profiles and, thus, reduced labeling efficiency. Through numerical simulation, phantom scans, and brain perfusion measurements, the dynamic phase-cycling method demonstrated considerable improvements over these issues. Conclusion: The proposed dynamic phase-cycling approach was demonstrated for the velocity-selective label and control modules with both velocity and spatial responses robust to a wide range of B0 and (Formula presented.) field inhomogeneities. © 2020 International Society for Magnetic Resonance in Medicine
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