Non-contrast compressed sensing whole-heart coronary magnetic resonance angiography at 3T: A comparison with conventional imaging

Abstract

Objectives: Whole-heart coronary magnetic resonance angiography (MRA) is a promising non-contrast, radiation-free technique for assessing the coronary artery. Yet, a disadvantage of coronary MRA is the relatively long acquisition time. The purpose of this study was to evaluate the scan time and image quality of compressed sensing (CS) coronary MRA compared with conventional coronary MRA.

Materials and methods: Twenty healthy volunteers underwent navigator-gated coronary MRA with a CS prototype sequence and conventional navigator-gated coronary MRA on a clinical 3T MRI scanner without contrast medium. The spatial resolutions were 1.33 × 1.33 × 1.20 mm³ for CS and 1.33 × 1.33 × 1.48 mm³ interpolated to 0.70 × 0.70 × 1.20 mm³ for conventional, respectively. We compared acquisition times, rated image quality on a 4-point scale (RCA; proximal, middle, and distal, LAD; main, proximal, middle, and distal, LCX; proximal and distal), and measured the visualized vessel lengths of three vessels.

Results: The mean acceptance rates were 44.9% for CS coronary MRA and 48.7% for conventional coronary MRA (p = .39). The mean effective scan time was 3 min 45 s for CS coronary MRA and 15 min 6 s for conventional coronary MRA (p < 0.001). Image quality scores were significantly lower for CS coronary MRA than for conventional coronary MRA (3.4 ± 0.7 for CS vs. 3.8 ± 0.4 for conventional; p < 0.0001). Conventional coronary MRA images were scored >3.4 in all segments on average, while CS coronary MRA images were scored >3.2 (good quality for diagnosis) in almost all segments, with only the distal RCA segment graded 2.9 on average. The average visible vessel lengths for CS and conventional coronary MRA were as follows: 11.5 ± 4.4 cm and 12.5 ± 4.8 cm for the RCA, respectively (p < 0.05, 95% limits of agreement [LOA]; -3.6 to 1.6 cm); 10.6 ± 3.0 cm and 11.1 ± 2.9 cm for the LAD, respectively (p = .15, 95% LOA -4.0 to 2.8 cm); and 7.1 ± 2.2 cm and 8.2 ± 2.5 cm for the LCX, respectively (p < 0.05, 95% LOA -4.0 to 1.7 cm).

Conclusions: Non-contrast coronary MRA using CS could largely shorten acquisition time, compared with conventional navigator-gated coronary MRA, while maintaining acceptable visualization at 3T.

Keywords: Compressed sensing; Coronary artery; Magnetic resonance angiography.