Background: Magnetic resonance coronary angiography (MRCA) is limited by a low signal-to-noise-ratio (SNR), low spatial resolution, and limited coverage of the coronary artery tree. These aspects might be significantly improved by intravascular contrast agents. The aim of the study was to evaluate the feasibility of whole-heart contrast-enhanced MRCA using the intravascular contrast agent gadofosveset, formerly known as MS-325.
Material/Methods: Free-breathing navigator-gated MRCA using a single 3D volume with transversal slice orientation before and after injection of MS-325 (0.05 mmol/kg body-weight) was performed in 17 volunteers (6 men, aged 30±8 years). Signal intensities from the myocardium and left ventricular blood were assessed for non-enhanced and contrast-enhanced images. Signal-to-noise ratio of blood and contrast-to-noise ratios (CNR) were calculated. Image quality (0: no visualization, 1: nondiagnostic, 2: moderate, 3: good, 4: excellent) and MR angiograms (15-segment model following AHA/ACC guidelines) were evaluated. Visible vessel length and vessel sharpness were measured and visible coronary artery segments assessed.
Results: MR coronary artery imaging using MS-325 was successfully performed in 16 volunteers. One volunteer was excluded from the analysis because of trigger problems. SNR did not improve significantly after administration of MS-325 (14.1 vs. 14.6, p=NS), but CNR did (8.03 vs. 12.73, p<0.001). Image quality increased with MS-325 from 2.5±0.4 to 2.8±0.3 (p<0.05). Overall vessel length and vessel sharpness improved significantly after MS-325 administration (p<0.05).
Conclusions: Whole-heart coronary MRA with the intravascular contrast agent MS-325 enables significant improvement in CNR, blood-myocardial contrast, image quality, visible vessel length, and vessel sharpness over non-contrast MRCA.

Keywords: Organometallic Compounds - diagnostic use, Magnetic Resonance Angiography - statistics & numerical data, Imaging, Three-Dimensional, Image Processing, Computer-Assisted, Heart - anatomy & histology, Gadolinium - diagnostic use, Coronary Vessels - anatomy & histology, Contrast Media, Contrast Media, Organometallic Compounds - diagnostic use, Magnetic Resonance Angiography - statistics & numerical data, Imaging, Three-Dimensional, Image Processing, Computer-Assisted, Heart - anatomy & histology, Gadolinium - diagnostic use, Coronary Vessels - anatomy & histology