Contrast-enhanced whole-heart coronary magnetic resonance angiography at 3.0 T: comparison with steady-state free precession technique at 1.5 T

OBJECTIVES: To compare contrast-enhanced whole-heart coronary MR angiography (MRA) at 3.0 T and noncontrast steady-state free precession coronary MRA at 1.5 T in the same volunteers.

MATERIALS AND METHODS: Nine healthy volunteers underwent both coronary MRA using 3D FLASH with slow infusion of MultiHance at 3.0 T and 3D TrueFISP sequence at 1.5 T. Neither beta-blockers nor nitroglycerine was administered in any of the imaging sessions. The same spatial resolution and heart coverage were used at both field strengths. Acquisition time, signal-to-noise ratio of coronary blood, contrast-to-noise ratio (CNR) between coronary blood and surrounding myocardium or connecting tissue, scores of image quality, coronary artery sharpness, and coverage of coronary segments for the 2 techniques were analyzed and statistically compared.

RESULTS: There were no significant differences in heart rate (68 +/- 10 vs. 63 +/- 6 beats/min, P > 0.05) and navigator efficiency (34.1% +/- 7.7% vs. 34.8% +/- 9.2%, P > 0.05) at 3.0 T and 1.5 T coronary MRA during the data acquisition. The average acquisition time of the 3.0 T coronary MRA was significantly shorter than that of the1.5 T coronary MRA (9.7 +/- 2.3 vs. 14.6 +/- 3.5, P < 0.05). The mean score of image quality and vessel sharpness at 3.0 T was similar to that at 1.5 T (2.8 +/- 1.0 vs. 3.0 +/- 1.0 and 0.63 +/- 0.15 vs. 0.61 +/- 0.13, respectively. P > 0.05). There was no significant difference between the number of visible coronary segments of the major coronary arteries at 3.0 T and 1.5 T (64/81 vs. 62/81, P > 0.05). However, the number of visible main coronary branches at 3.0 T was significantly higher than that at 1.5 T (18/54 vs. 7/54, P < 0.05). The overall signal-to-noise ratio at 3.0 T was significantly lower than that at 1.5 T (40.9 +/- 4.7 vs. 60.9 +/- 3.4, P < 0.01), whereas the overall CNR at 3.0 T was significantly higher than that at 1.5 T (35.4 +/- 3.3 vs. 28.8 +/- 6.4, P < 0.05).

CONCLUSION: Contrast-enhanced whole-heart coronary MRA at 3.0 T demonstrated less acquisition time, higher CNR, and better depiction of coronary segments compared with steady-state free precession coronary MRA at 1.5 T. Patient studies are required to evaluate the clinical value of the technique.