The SASHA sequence is a simple and fast approach to in vivo T1 mapping with good accuracy in simulations and phantom experiments.

T2*-CMR accurately quantified myocardial reperfusion hemorrhage in vivo. Hemorrhage was associated with more severe infarct-related injury.

Background-We tested the hypothesis that real-time magnetic resonance imaging (MRI) can guide coronary artery catheterization in swine via a percutaneous femoral artery approach. Methods and Results-In 12 pigs, we accessed femoral arteries percutaneously. We used 6-or 7-French coronary Judkins catheters filled with dilute 4% gadolinium (Gd) contrast agent and coaxially inserted 0.030-inch diameter active guidewires as endovascular devices. For catheter tracking, we used a 2-dimensional (2D) inversion recovery-prepared spoiled gradient echo sequence at a temporal resolution of 7 frames/s. For guidewire tracking, we used 2D steady-state free precession imaging at a temporal resolution of 9 frames/s. Coronary artery catheterization under MRI guidance was successful in 12/12 pigs. Successful coronary catheterization was verified by obtaining MR angiographic images after direct catheter-based injections of dilute Gd. Conclusions-Real-time MRI-guided catheterization of coronary arteries in swine is feasible via a percutaneous femoral artery approach. Selective coronary MR angiography can then be performed with dilute contrast agent injections. Key Words: magnetic resonance imaging Ⅲ catheterization Ⅲ arteries Ⅲ angiography M agnetic resonance imaging (MRI) guidance for diagnostic and therapeutic endovascular procedures has several potential advantages over conventional x-ray guidance. Compared with x-ray guidance, MRI (1) avoids ionizing radiation exposure; (2) limits potential nephrotoxic effects and allergic reactions of iodinated contrast agents; (3) provides 3-dimensional anatomic information; and (4) has the ability to measure changes in end-organ function. Catheterbased coronary MR angiography (MRA) is feasible using dilute contrast agent injections. 1 However, MRI-guided catheterization of the coronary arteries is difficult because limited signal detection constrains spatial and temporal resolution for device tracking. An active internal guidewire used in conjunction with a contrast agent-filled catheter is one approach 2 to improve signal detection of endovascular devices. Using this approach, we tested the hypothesis that MRI can successfully guide real-time coronary catheterization in swine. MethodsOur institution's Animal Care and Use Committee approved all animal experiments. We performed experiments in 12 healthy domestic female swine (22 to 35 kg; Oak Hill Genetics, Ewing, Ill). After endotracheal intubation, they received inhaled isoflurane during mechanical ventilation. In our animal laboratory, sonography was used to guide percutaneous common femoral artery puncture.After placing 6-to 8-French vascular sheaths under x-ray guidance, we administered intravenous heparin 5000 U. Preliminary coronary x-ray angiography was performed with a Judkins catheter (curve sizes 2.5 to 3.5) and the catheter was removed. We then transferred the animals to a 1.5 T MRI scanner (Sonata, Siemens) for subsequent experiments.For real-time catheter tracking, we used an 80-cm length 6-or 7-French Judkins coronary catheter (Co...