Breathhold three-dimensional coronary magnetic resonance angiography usingreal-time navigator technology

The acquisition duration of most three-dimensional (3D) coronary magnetic r esonance angiography (MRA) techniques is consider-ably prolonged thereby pr ecluding breathholding as a mechanism to suppress respiratory motion artifa cts. Splitting the acquired 3D volume into multiple subvolumes or slabs ser ves to shorten individual breathhold duration. Skill, problems associated w ith misregistration due to inconsistent depths of expiration and diaphragma tic drift during sustained respiration remain to be resolved. We propose th e combination of an ultrafast 3D coronary MRA imaging sequence with prospec tive real-time navigator technology, which allows correction of the measure d volume position. 3D volume splitting using prospective real-time navigator technology, was s uccessfully applied for 3D coronary MRA in five healthy individuals. An ult rafast 3D interleaved hybrid gradient-echoplanar imaging sequence, includin g T2Prep for contrast enhancement, was used with the navigator localized at the basal anterior wall of the left ventricle. A 9-cm-thick volume, with i n-plane spatial resolution of 1.1 X 2.2 mm, was acquired during five breath holds of 15-sec duration each. Consistently, no evidence of misregistration was observed in the images. Extensive contiguous segments of the left ante rior descending coronary artery (48 +/- 18 mm) and the right coronary arter y (75 +/- 5 mm) could be visualized. This technique has the potential for s creening for anomalous coronary arteries, making it well suited as part of a larger clinical MR examination. In addition, this technique may also be a pplied as a scout scan, which allows an accurate definition of imaging plan es for subsequent high-resolution coronary MRA.