Noninvasive in vivo magnetic resonance imaging of experimental coronary artery lesions in a porcine model.

BACKGROUND The ability to characterize and quantify coronary artery atherosclerotic lesions accurately, reproducibly, and noninvasively may allow the stratification of risk for future acute coronary syndromes and help direct therapeutic management. MRI has been shown to accurately characterize and quantify atherosclerosis; however, because of the combination of cardiac and respiratory motion artifacts, nonlinear course, and relatively small size of the coronary arteries, these techniques have not been able to be translated to the coronary system in vivo. METHODS AND RESULTS Coronary lesions were induced in Yorkshire albino swine (n=6) with balloon angioplasty, and 4 weeks later MRI of the coronary artery lesions was performed. High-resolution in vivo images of the coronary artery wall and lesions were obtained with a double-inversion-recovery fast-spin-echo sequence in a 1.5-T MR system. There was good agreement between measurements of vessel wall thickness and area from MR images of the coronary arteries and the matched histopathology sections (n=43). The mean difference (MRI minus histopathology +/- SD) for mean wall thickness was 0.26+/-0.18 mm, and for vessel wall area, 5.65+/-3.51 mm(2). MRI was also able to visualize intralesion hematoma (sensitivity 82%, specificity 84%). CONCLUSIONS Using a clinical MR system, we were able to image coronary artery lesions in vivo in an experimental porcine model. Further studies are needed to assess the ability of MRI to characterize coronary atherosclerotic lesions in vivo.