Abstract 2424: Detection of Coronary Atherosclerotic Plaque with Free Breathing Whole Heart Coronary Magnetic Resonance Angiography
PURPOSE Free breathing whole heart coronary MRA can provide noninvasive visualization of luminal narrowing in the coronary artery. The purpose of this study was to determine if coronary atherosclerotic plaque can be detected by using a whole heart coronary MRA sequence in the segments with significant coronary artery disease (CAD).
METHOD AND MATERIALS Twenty-four patients (mean age 67.9±12.2 years) who underwent whole heart coronary MRA following late gadolinium enhanced MRI and had significant CAD (luminal diameter reduction of ≥50%) on X-ray coronary angiography were retrospectively evaluated. Axial 3D MRA images covering the entire coronary artery tree were obtained with a navigator-gated balanced TFE sequence with radial k-space sampling (TR/TE=4.6/2.3ms, SENSE factor=2, FOV=280x280x120mm, acquisition matrices=256x256x80, reconstructed voxel size=0.55x0.55x0.75mm).
RESULTS Whole heart coronary MRA correctly identified 22 (85%) of 26 luminal stenoses detected by X-ray coronary angiography. The averaged lumen diameter of the stenosis, reference diameter, and %stenosis determined by coronary MRA were 0.9mm±0.5, 3.0mm±0.6mm, 68%±16, showing good agreements with the results by x-ray coronary angiography (1.3mm±0.4, 3.1mm±0.7 and 58%±10, respectively). Coronary atherosclerotic plaque was visualized with sufficient diagnostic confidence in 14 (64%) of 22 stenoses that were identified on coronary MRA. The mean thickness of coronary plaque visualized on MRA was 2.4±0.6mm. Coronary plaque was demonstrated as area of intermediate signal intensity (SI), with the averaged SI plaque / SI blood ratio of 0.47±0.12 and the averaged SI plaque /SI fat ratio of 3.1±1.0. Detection rate of noncalcified plaque (11/18, 61%) was substantially better than that of calcified plaque (2/8, 25%) on coronary MRA.
CONCLUSION The results in this study demonstrated that noncalcified coronary atherosclerotic plaque with thickness of 1.5 mm or greater can be identified on free breathing whole heart coronary MRA that was acquired following late gadolinium enhanced MRI.