Magnetic resonance imaging of the coronary vessel wall at 3 T using an obliquely oriented reinversion slab with adiabatic pulses

Abstract

Three-dimensional methods offer volumetric coverage in coronary vessel wall imaging, in addition to high signal-to-noise ratios (SNR). To increase SNR further, it is desirable to implement such 3D methods at 3 T. At this field strength, the pulse sequence must be robust to main field and RF inhomogeneities. To achieve this, the double inversion-recovery (DIR) preparation was adapted to use adiabatic pulses, with a slab-selective reinversion replacing the previously used 2D pencil-beam. The slab was oriented obliquely, in order to avoid upstream blood (e.g., left ventricle) or the navigator beam. Phantom experiments suggest that at 3 T, this approach improves both the net profile of the DIR pulse pair and the restoration of magnetization in the navigator region. Using this method, the feasibility of 3D coronary vessel wall imaging was demonstrated at 3 T. Fourteen healthy subjects were scanned using a segmented gradient-echo sequence with prospective navigator gating. Good-quality images of left and right coronary arteries were obtained, with SNR values of 29.7 +/- 7.5 (vessel wall); 10.5 +/- 4.4 (blood); 14.3 +/- 5.2 (fat); and 45.6 +/- 18.0 (myocardium). No problems occurred with ECG-gating or power deposition (SAR) limits.