Journal article
Time-encoded pseudo-continuous arterial spin labeling: increasing SNR in ASL dynamic angiography
- Abstract:
- Purpose Dynamic angiography using arterial spin labeling (ASL) can provide detailed hemodynamic information. However, the long time-resolved readouts require small flip angles to preserve ASL signal for later timepoints, limiting SNR. By using time-encoded ASL to generate temporal information, the readout can be shortened. Here, the SNR improvements from using larger flip angles, made possible by the shorter readout, are quantitatively investigated. Methods The SNR of a conventional protocol with nine Look-Locker readouts and a 4 3 time-encoded protocol with three Look-Locker readouts (giving nine matched timepoints) were compared using simulations and in vivo data. Both protocols were compared using readouts with constant flip angles (CFAs) and variable flip angles (VFAs), where the VFA scheme was designed to produce a consistent ASL signal across readouts. Optimization of the background suppression to minimize physiological noise across readouts was also explored. Results The time-encoded protocol increased in vivo SNR by 103% and 96% when using CFAs or VFAs, respectively. Use of VFAs improved SNR compared with CFAs by 25% and 21% for the conventional and time-encoded protocols, respectively. The VFA scheme also removed signal discontinuities in the time-encoded data. Preliminary data suggest that optimizing the background suppression could improve in vivo SNR by a further 16%. Conclusions Time encoding can be used to generate additional temporal information in ASL angiography. This enables the use of larger flip angles, which can double the SNR compared with a non-time-encoded protocol. The shortened time-encoded readout can also lead to improved background suppression, reducing physiological noise and further improving SNR.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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(Preview, Supplementary materials, pdf, 2.4MB, Terms of use)
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(Preview, Version of record, pdf, 4.6MB, Terms of use)
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- Publisher copy:
- 10.1002/mrm.29491
Authors
- Publisher:
- Wiley
- Journal:
- Magnetic Resonance in Medicine More from this journal
- Volume:
- 89
- Issue:
- 4
- Pages:
- 1323-1341
- Publication date:
- 2022-10-18
- Acceptance date:
- 2022-09-23
- DOI:
- EISSN:
-
1522-2594
- ISSN:
-
0740-3194
- Language:
-
English
- Keywords:
- Pubs id:
-
1280111
- Local pid:
-
pubs:1280111
- Deposit date:
-
2022-09-28
Terms of use
- Copyright holder:
- Woods et al.
- Copyright date:
- 2022
- Rights statement:
- © 2022 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
- Licence:
- CC Attribution (CC BY)
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