Contrast-enhanced MR imaging of coronary arteries: Comparison of intra- and extravascular contrast agents in swine

PURPOSE: To compare the efficacy of an intravascular contrast agent, gadome r-17, in improving magnetic resonance (MR) imaging of coronary arteries wit h that of an extravascular agent, gadopentetate dimeglumine, in pigs. MATERIALS AND METHODS: Eight pigs underwent imaging after three injections: 0.20 mmol of gadopentetate dimeglumine per kilogram of body weight and 0.0 5 and 0.10 mmol/kg gadomer-17. Coronary images were acquired repeatedly aft er each injection by using an inversion-recovery-prepared segmented three-d imensional sequence with either breath holding (n = 4) or respiratory gatin g (n = 4). Coronary artery-to-myocardium contrast-to-noise ratios (CNRs) we re compared between injections. RESULTS: At breath-hold imaging, substantial CNR improvement over precontra st images was observed in images acquired during the first pass of gadopent etate dimeglumine in coronary arteries and up to 6 and 10 minutes after 0.0 5 and 0.10 mmol/kg of gadomer-17 injections, respectively. The CNR with 0.1 0 mmol/kg of gadomer-17 was 20% (P < .05) higher than that with gadopenteta te dimeglumine at first-pass imaging. At respiratory-gated imaging, signifi cant CNR improvement (P < .05) over precontrast images was observed in imag es acquired up to 10, 30, and 50 minutes after gadopentetate dimeglumine an d both gadomer-17 injections, respectively. The CNR on the first images obt ained after 0.10 mmol/kg gadomer-17 injection was 168% (P < .05) higher tha n that on the images obtained after gadopentetate dimeglumine injection. CONCLUSION: Gadomer-17 provided greater and more persistent CNR improvement s than did gadopentetate dimeglumine; further evaluation of its utility for coronary imaging in humans is warranted.