To assess the effectiveness of an intravascular contrast agent, MS‐325, for enhancing the vascular signal in coronary MR angiograms, six minipigs were studied using a three‐dimensional, gradient‐echo sequence with retrospective respiratory gating. To suppress the myocardial signal, preparatory RF pulses were applied before data acquisition. With the administration of MS‐325, the blood signal‐to‐noise ratio increased by 97‐276%, depending on the region of interest in which the blood signal was measured and the precontrast imaging sequence structures. The blood/myocardium contrast‐to‐noise ratio also significantly increased. High‐resolution images (0.58 × 0.58 × 1 mm3) obtained from postmortem pig hearts demonstrated the potential delineation of coronary arteries with MS‐325. In conclusion, this study supports further evaluation of the utility of MS‐325 in improving coronary MR angiography in humans.