Magnetic resonance angiography of the coronary arteries

Objectives: Evaluate magnetic resonance imaging of the coronary arteries. Methods: The study was conducted in 18 healthy volunteers (mean age 26 years, range 22-32). A superconducting magnet operating at 1.5 Tesla was used with an in-phase matrix surface coil. Images were obtained with 2D acquisition with flow compensation on ultra-rapid echo gradient sequences coupled with the electrocardiogram and segmentation of the Fourier plane. A coronary image was obtained during a 15 to 20 sec apnea. Frontal slices were used to identify cardiac structures before selecting axial slices starting from the origin of the aorta to the coronary ostia. Orthogonal, oblique and radial slices were then obtained starting from the axial slices. Slice thickness was 3 to 5 mm separated by 0.5 mm with a 30 degrees angle and a 320 mm field. Echo times were 5.8 and 10.3 msec with 2 excitations, Heart rate varied from 59 to 85 sec giving 15 to 18 ms repetition and 96 to 144 msec time resolution. Results: The proximal, middle and disatal segments of the right coronary artery were seen in 100% of the subjects, the common left coronary artery in 100%, the proximal anterior interventricular artery in 83% and the proximal circumflex artery in 80%. All the coronary arteries were visualized on at least two slices with different incidences. The proximal measurements were: common trunk 3.75 +/- 0.66 mm; anterior interventricular 3.25 +/- 0.43 mm; circumflex 2.62 +/- 0.48; right coronary 3.37 +/- 0.51. Conclusion: Magnetic resonance angiography provides good visualization of the coronary arteries.