PURPOSE: To prospectively assess the accuracy of breath-hold three-dimensional magnetic resonance (MR) coronary angiography with the gadolinium-based intravascular contrast agent SH L 643 A in patients with coronary artery disease. MATERIALS AND METHODS: Twelve patients (seven men, five women; age range, 46-78 years; mean age, 61.3 years) with angiographically proved coronary artery disease (luminal narrowing >50%) underwent breath-hold three-dimensional MR coronary angiography before and after injection of SH L 643 A (0.1 mmol gadolinium per kilogram body weight). For all MR examinations, signal-to-noise ratio and contrast-to-noise ratio were measured. Image quality was assessed with a four-point scale. Conventional angiograms and MR angiograms were evaluated for depiction of the left main, proximal and middle left anterior descending, proximal left circumflex, and proximal and middle right coronary artery segments in a blinded fashion by two experienced readers in consensus. Results of this evaluation were compared by using a paired Student t test. P < .05 was considered to indicate a statistically significant difference. RESULTS: For the 72 coronary artery segments, the contrast-to-noise ratio significantly improved after administration of SH L 643 A, compared with the prior ratio (9.8 ± 5.1 [standard deviation] vs 23.0 ± 8.7; P < .01), whereas the difference in signal-to-noise ratio did not reach statistical significance (25.2 ± 11.4 vs 29.5 ± 9.8; P > .3). Image quality significantly improved from a mean of 2.0 ± 0.9 for nonenhanced images to 2.9 ± 0.9 (P < .03) for contrast material-enhanced images. The proportion of segments for which images were nondiagnostic decreased from 38% to 10% with application of SH L 643 A. Overall sensitivity and specificity of contrast-enhanced MR coronary angiography for detection of coronary artery disease were 80% and 93%, respectively, and accuracy was 87%. CONCLUSION: Use of SH L 643 A improves detection of coronary artery disease at three-dimensional MR coronary angiography.