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Efficient triple‐VENC phase‐contrast MRI for improved velocity dynamic range
Author(s) -
Ma Liliana E.,
Markl Michael,
Chow Kelvin,
Vali Alireza,
Wu Can,
Schnell Susanne
Publication year - 2020
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.27943
Subject(s) - pulsatile flow , imaging phantom , intraclass correlation , mathematics , nuclear medicine , biomedical engineering , medicine , reproducibility , statistics
Purpose To evaluate the utility of an efficient triple velocity‐encoding (VENC) 4D flow MRI implementation to improve velocity unwrapping of 4D flow MRI data with the same scan time as an interleaved dual‐VENC acquisition. Methods A balanced 7‐point acquisition was used to derive 3 sets of 4D flow images corresponding to 3 different VENCs. These 3 datasets were then used to unwrap the aliased lowest VENC into a minimally aliased, triple‐VENC dataset. Triple‐VENC MRI was evaluated and compared with dual‐VENC MRI over 3 different VENC ranges (50‐150, 60‐150, and 60‐180 cm/s) in vitro in a steadily rotating phantom as well as in a pulsatile flow phantom. In vivo, triple‐VENC data of the thoracic aorta were also evaluated in 3 healthy volunteers (2 males, 26‐44 years old) with VENC = 50/75/150 cm/s. Two triple‐VENC (triconditional and biconditional) and 1 dual‐VENC unwrapping algorithms were quantitatively assessed through comparison to a reference, unaliased, single‐VENC scan. Results Triple‐VENC 4D flow constant rotation phantom results showed high correlation with the analytical solution (intraclass correlation coefficient = 0.984‐0.995, P < .001) and up to a 61% reduction in velocity noise compared with the corresponding single‐VENC scans (VENC = 150, 180 cm/s). Pulsatile flow phantom experiments demonstrated good agreement between triple‐VENC and single‐VENC acquisitions (peak flow < 0.8% difference; peak velocity < 11.7% difference). Triconditional triple‐VENC unwrapping consistently outperformed dual‐VENC unwrapping, correctly unwrapping more than 83% and 46%‐66% more voxels in vitro and in vivo, respectively. Conclusion Triple‐VENC 4D flow MRI adds no additional scan time to dual‐VENC MRI and has the potential for improved unwrapping to extend the velocity dynamic range beyond dual‐VENC methods.