3D coronary MR angiography at 1.5 T: Volume-targeted versus whole-heart acquisition

Purpose: To compare volume-targeted acquisition with whole-heart acquisition in 1.5-T free-breathing 3D coronary magnetic resonance angiography (MRA) with parallel imaging.

Materials and methods: The major coronary arteries were imaged in 36 subjects using the whole-heart and volume-targeted acquisitions with comparable imaging parameters. The quantitative and semiquantitative data derived from these two acquisition methods were analyzed statistically, with P < 0.05 considered significant.

Results: Both the right coronary artery (RCA) / left circumflex artery (LCX)- and the left main (LM) / left anterior descending (LAD)-targeted acquisitions had similar results in navigator efficiencies and apparent signal-to-noise ratio (SNR) in comparison with whole-heart acquisition. Apparent contrast-to-noise ratio (CNR) of the volume-targeted imaging was significantly higher than that of the whole-heart imaging. The imaging time required for a whole-heart scan was significantly longer than each of the RCA/LCX- and LM/LAD-targeted acquisitions. However, the sum of scanning times derived from volume-targeted imaging was significantly longer than that of whole-heart acquisition. Both RCA/LCX- and LM/LAD-targeted acquisition yield higher vessel sharpness and overall image quality in comparison with whole-heart acquisition. The lengths of the major coronary arteries were not significantly different for the whole-heart and volume-targeted approaches. The whole-heart method was obviously superior to the volume-targeted method in terms of visualization of the posterior descending artery.

Conclusion: For current 1.5-T navigator coronary MRA, volume-targeted and whole-heart acquisitions have their own advantages and the choice of methods may vary in accordance with the different aims of clinical practice.