[Magnetic resonance angiography of coronary arteries: assessment in patients with coronary stenosis and control after stent positioning]

Abstract

Introduction: Cardiovascular disease remains the leading cause of death in the world. Invasive coronary angiography is currently the only clinical method available to visualize the coronary arteries, with up to 20% of the procedures demonstrating no evidence of severe coronary artery stenoses. We investigated the role of two-dimensional (2D) coronary magnetic resonance angiography (MRA) in patients with suspected coronary arteries disease and to check the placement and the patency of previously placed coronary artery stents.

Material and methods: Eleven patients with suspected coronary artery disease who underwent elective cardiac catheterization with coronary angiography were examined with 2D coronary MRA to detect coronary artery stenoses. Other 11 patients with 13 stented coronary arteries (6 RCA, 5 LAD, 2 Lcx) were prospectively examined with MRA one day to 8 months after stent placement. Eighteen amagnetic stents were imaged. Imaging was performed with a 1.5 T MR unit (GE Signa Horizon Echo Speed) with a phased array multicoil. Segmented k-space fast GE sequences were acquired with and without fat suppression at several cardiac cycle phases within a single breath-hold. Correlation with coronary angiography was performed in all patients.

Results: Thirteen significant stenoses were found at coronary angiography in 11 coronary arteries. The sensitivity and specificity of MR coronary angiography, as compared with conventional angiography, in correctly identifying the single vessels with > 50% angiographic stenoses were 73% and 94%, respectively. The corresponding positive and negative predictive values and accuracy were 88%; 84% and 86%, respectively. As far as the study of coronary artery stents is concerned, no MR-related adverse events were observed. The stents were visualized as signal loss areas. The length of the signal loss corresponded to the length of the stents in all 18 cases (r = 97). The patent blood flow distal to the stents appeared as a high-signal band distal to the signal void, corresponding to stent patency at coronary angiography.

Conclusions: Although in an early stage of technical development, 2D coronary MRA can depict 73% of hemodynamically severe coronary artery stenoses. Moreover breath-hold coronary cine MRA is a safe technique to visualize coronary artery stents. Stent site and patency can be noninvasively studied with this technique.