https://scholars.lib.ntu.edu.tw/handle/123456789/630628
標題: | A theoretical and experimental investigation of the tagging efficiency of pseudocontinuous arterial spin labeling | 作者: | WEN-CHAU WU Fernández-Seara, María Detre, John A Wehrli, Felix W Wang, Jiongjiong |
關鍵字: | pseudocontinuous arterial spin labeling; arterial spin labeling; magnetic resonance imaging; blood flow; perfusion; CEREBRAL-BLOOD-FLOW; MAGNETIC-RESONANCE; STEADY-STATE; PERFUSION; INVERSION; TESLA; QUANTIFICATION; SENSITIVITY; VALIDATION; SATURATION | 公開日期: | 十一月-2007 | 出版社: | WILEY | 卷: | 58 | 期: | 5 | 起(迄)頁: | 1020 | 來源出版物: | Magnetic resonance in medicine | 摘要: | Arterial spin labeling (ASL) is capable of noninvasively measuring blood flow by magnetically tagging the protons in arterial blood, which has been conventionally achieved using instantaneous (PASL) or continuous (CASL) RF pulses. As an intermediate method, pseudocontinuous ASL (pCASL) utilizes a train of discrete RF pulses to mimic continuous tagging that is often unavailable on imagers due to the requirement of continuous RF transmit capabilities. In the present study, we implemented two versions of pCASL (balanced and unbalanced gradient waveforms in tag and control scans) for both transmit/receive coils and array receivers. Experimental data show a 50% +/- 4% increase of signal-to-noise ratio (SNR) compared with PASL and a higher tagging efficiency than amplitude-modulated (AM) CASL (80% vs. 68%). Computer simulations predict an optimal tagging efficiency of 85% for flow velocities from 10 to 60 cm/s. It is theoretically and experimentally demonstrated that the tagging efficiency of pCASL is dependent upon the resonance offset and flip angle of the RF pulse train. We conclude that pCASL has the potential of combining the merits of PASL, including less hardware demand and higher tagging efficiency, and CASL, which includes a longer tagging bolus and thus higher SNR. These improvements provide a better balance between tagging efficiency and SNR. |
URI: | https://scholars.lib.ntu.edu.tw/handle/123456789/630628 | ISSN: | 0740-3194 | DOI: | 10.1002/mrm.21403 |
顯示於: | 醫療器材與醫學影像研究所 |
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