TY - JOUR
T1 - Cardiac-triggered pseudo-continuous arterial-spin-labeling
T2 - A cost-effective scheme to further enhance the reliability of arterial-spin-labeling MRI
AU - Li, Yang
AU - Mao, Deng
AU - Li, Zhiqiang
AU - Schär, Michael
AU - Pillai, Jay J.
AU - Pipe, James G.
AU - Lu, Hanzhang
N1 - Publisher Copyright:
© 2018 International Society for Magnetic Resonance in Medicine
PY - 2018/9
Y1 - 2018/9
N2 - Purpose: Arterial-spin-labeling (ASL) magnetic resonance imaging (MRI) is intrinsically a low signal-to-noise ratio (SNR) technique. This study aims to enhance its sensitivity by quantifying physiological noise attributed to cardiac pulsation and devising an improved sequence, cardiac-triggered ASL, to minimize this noise. Methods: A total of 16 healthy subjects were studied on a 3 Tesla MRI system. The influence of cardiac pulsation on pseudo-continuous ASL (pCASL) signal was first investigated by performing a regular pCASL sequence while the cardiac phase of the image acquisition was recorded by a pulse oximeter. We then designed a new sequence, cardiac-triggered pCASL, to align the cardiac phases of the control and labeled scans. The performance of the new sequence was evaluated in the context of single-shot 3D gradient-and-spin-echo acquisition, multishot 3D spiral acquisition, and hypercapnia-induced cerebral blood flow (CBF) changes. Results: In regular pCASL, the signal intensities of both control and labeled images were strongly modulated by the cardiac phase. In single-shot acquisitions, this results in signal instability in regions near large vessels. In segmented acquisitions, it results in ghosting artifacts in the image and, furthermore, the signal fluctuation is smeared along the segmentation direction to affect more brain regions. Cardiac-triggered pCASL enhanced the temporal SNR by 94% and 28% in single-shot and segmented 3D acquisition, respectively. When applied to detect CBF changes, the triggered sequence revealed a greater statistical power in terms of both the number of significant voxels and t-score histograms. Conclusion: Cardiac-triggered pCASL represents a potential scheme to enhance the reliability of ASL signal. Magn Reson Med 80:969–975, 2018.
AB - Purpose: Arterial-spin-labeling (ASL) magnetic resonance imaging (MRI) is intrinsically a low signal-to-noise ratio (SNR) technique. This study aims to enhance its sensitivity by quantifying physiological noise attributed to cardiac pulsation and devising an improved sequence, cardiac-triggered ASL, to minimize this noise. Methods: A total of 16 healthy subjects were studied on a 3 Tesla MRI system. The influence of cardiac pulsation on pseudo-continuous ASL (pCASL) signal was first investigated by performing a regular pCASL sequence while the cardiac phase of the image acquisition was recorded by a pulse oximeter. We then designed a new sequence, cardiac-triggered pCASL, to align the cardiac phases of the control and labeled scans. The performance of the new sequence was evaluated in the context of single-shot 3D gradient-and-spin-echo acquisition, multishot 3D spiral acquisition, and hypercapnia-induced cerebral blood flow (CBF) changes. Results: In regular pCASL, the signal intensities of both control and labeled images were strongly modulated by the cardiac phase. In single-shot acquisitions, this results in signal instability in regions near large vessels. In segmented acquisitions, it results in ghosting artifacts in the image and, furthermore, the signal fluctuation is smeared along the segmentation direction to affect more brain regions. Cardiac-triggered pCASL enhanced the temporal SNR by 94% and 28% in single-shot and segmented 3D acquisition, respectively. When applied to detect CBF changes, the triggered sequence revealed a greater statistical power in terms of both the number of significant voxels and t-score histograms. Conclusion: Cardiac-triggered pCASL represents a potential scheme to enhance the reliability of ASL signal. Magn Reson Med 80:969–975, 2018.
KW - arterial spin labeling
KW - cardiac phase
KW - cardiac-triggered
KW - pulsation
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U2 - 10.1002/mrm.27090
DO - 10.1002/mrm.27090
M3 - Article
C2 - 29369422
AN - SCOPUS:85041039836
SN - 0740-3194
VL - 80
SP - 969
EP - 975
JO - Magnetic Resonance in Medicine
JF - Magnetic Resonance in Medicine
IS - 3
ER -