Combined use of the intravascular blood-pool agent, gadomer, and carbon dioxide: A novel type of double-contrast magnetic resonance angiography (MRA)

Purpose: To evaluate the combined use of carbon dioxide (CO₂) and a gadolinium-based blood-pool agent for magnetic resonance angiography (MRA). Materials and Methods: After an initial intravenous injection of the blood-pool agent Gadomer (Schering AG, Germany), repeated transcatheter CO ₂ injections were performed in the aorta and the renal arteries of two fully-anesthetized pigs. Real-time images were acquired using a true fast imaging with steady-state precession (FISP) sequence. Results: During the CO₂ injections, the Gadomer-enhanced blood was totally replaced, resulting in an immediate, temporary, total signal loss in the vessel lumen. Susceptibility artifacts during the injections or catheter manipulations rarely occurred. Conclusion: Due to T1-shortening, the circulating blood-pool agent prevents flow artifacts during catheter manipulations because the steady-state is reached much earlier. Therefore, this double-contrast MRA method improves catheter conspicuity and might be helpful for guiding and controlling intravascular procedures during interventional MRI.