Phase contrast coronary blood velocity mapping with both high temporal and spatial resolution using triggered Golden Angle rotated Spiral k‐t Sparse Parallel imaging (GASSP) with shifted binning

• Published in: Magnetic resonance in medicine Vol. 86; no. 4; pp. 1929 - 1943
• Main Authors: Zhu, Dan, Bonanno, Gabriele, Hays, Allison G., Weiss, Robert G., Schär, Michael
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.10.2021
• Subjects: Arteries; Blood flow; Blood vessels; Coronary artery; coronary flow; coronary MRI; coronary velocity; Correlation coefficients; Data acquisition; Flow velocity; golden angle; Heart; In vivo methods and tests; k‐t sparse SENSE; Magnetic resonance imaging; Phase contrast; Reproducibility; Spatial discrimination; Spatial resolution; spiral MRI; Temporal resolution; k-t sparse SENSE; spiral MRI; coronary flow; coronary velocity; coronary MRI; golden angle
• ISSN: 0740-3194; 1522-2594; 1522-2594
• DOI: 10.1002/mrm.28837

Purpose High temporal and spatial resolutions are required for coronary blood flow measures. Current spiral breath‐hold phase contrast (PC) MRI at 3T focus on either high spatial or high temporal resolution. We propose a golden angle (GA) rotated Spiral k‐t Sparse Parallel imaging (GASSP) sequence for both high spatial (0.8 mm) and high temporal (<21 ms) resolutions. Methods GASSP PC data are acquired in left anterior descending and right coronary arteries of eight healthy subjects. Binning of GA rotated spiral data into cardiac frames may lead to large k‐space gaps. To reduce those gaps, the binning window is shifted and a triggered GA scheme that resets the rotation angle every heartbeat is proposed. The gap reductions are evaluated in simulations and all subjects. Peak systolic velocity (PSV), peak diastolic velocity (PDV), coronary blood flow rate, and vessel area are validated against two reference scans, and repeatability/reproducibility are determined. Results Shifted binning reduced the mean k‐space gaps of the triggered GA scheme by 14°‐22° in simulations and about 20° in vivo. The k‐space gap across three cardiac frames was reduced with the triggered GA scheme compared to the standard GA scheme (35.3°± 3.6° vs. 43°± 13.7°, t‐test P = .04). PSV, PDV, flow rate, and area had high intra‐scan repeatability (0.92 ≤ intraclass correlation coefficient [ICC] ≤ 0.99), and inter‐scan (0.78 ≤ ICC ≤ 0.91) and intra‐observer (0.91 ≤ ICC ≤ 0.98) reproducibility. Conclusion GASSP enables single breath‐hold coronary PC MRI with high temporal and spatial resolutions. Shifted binning and a triggered GA scheme reduce k‐space gaps. Quantitative coronary flow metrics are highly reproducible, especially within the same scanning session.