Abstract 2806: Whole Heart Coronary Magnetic Resonance Angiography Using 32-Channel Cardiac Coils and High Parallel Imaging Factor
PURPOSE Coronary MRA provides noninvasive detection of coronary artery disease (CAD) without administration of contrast medium or exposing the patient to radiation. However, use of coronary MRA in excluding patients with CAD has been limited due to lengthy imaging time. The purpose of this study was to reduce acquisition time of coronary MRA by using 32 channel cardiac coils and high parallel imaging factor, and to evaluate diagnostic performance of this method in detecting significant CAD.
METHOD AND MATERIALS Sixty-two patients with suspected CAD were studied. Free-breathing coronary MRA encompassing the entire heart was acquired by using 32-channel coils and SENSE factor of 4. After monitoring motion of the coronary artery on cine MRI, MR angiograms were acquired during diastole in 46 patients (acquisition window 82±57ms) and during systole in 16 patients (50±19ms). Coronary MRA images were interpreted by 2 observers by employing a sliding SLAB MIP method. All patients underwent X-ray coronary angiography within 4 weeks from MRA, and significant CAD was defined as a luminal diameter reduction of 50% or more by QCA. All lesions with a reference diameter of 2mm or more on X-ray angiography were included when determining the accuracy of coronary MRA.
RESULTS Acquisition of MRA was completed in all 62 patients, with the averaged imaging time of 6.1±2.6min. High SENSE factor achieved by 32-channel coils resulted in substantial reduction of imaging time by factor of >2, with the image quality score (4.6±0.2) at least equivalent to that by conventional 5-channel coils and SENSE factor of 2 (4.5±0.2). Significant CAD was observed on X-ray coronary angiography in 39 patients. MRA detected 33(85%) of 39 patients having CAD, with high specificity of 96%(22/23). All 16 patients with double- or triple-vessel diseases were detected by MRA. On a vessel based analysis, Whole-heart coronary MRA demonstrated sensitivity of 83%(49/59), specificity of 94%(119/127) and NPV of 92%(119/129).
CONCLUSION Whole-heart coronary MRA with 1.5T MR imager and 32-chennel coils permits noninvasive detection of CAD with substantially reduced imaging time and high study success rate. High NPV (>90%) indicated the value of this approach in ruling out significant CAD.