Intracoronary MR imaging using a 0.014‐inch MR imaging‐guidewire: Toward MRI‐guided coronary interventions

Purpose To validate the feasibility of using a newly designed MR imaging‐guidewire (MRIG) to guide angioplasty balloon placement in coronary arteries. Materials and Methods A custom gold/sliver/Nitinol/MP35N‐based, 0.014‐inch MRIG was manufactured. To test its mechanical performance we used the new MRIG to catheterize the left coronary arteries of three dogs under x‐ray fluoroscopy. To further validate the feasibility of using the MRIG to generate intracoronary MR imaging, we positioned the MRIG, along with a dilation‐perfusion balloon catheter, into the left coronary arteries of an additional three dogs. Longitudinal and four‐chamber views of cine cardiac MR images were obtained using a fast gradient recalled echo (FGRE) sequence (TR/TE/FA = 5.2 msec/1.6 msec/20°, field of view [FOV] = 32 × 32 cm, thickness = 5 mm, space = 2 mm, matrix = 256 × 160, number of excites [NEX] = 0.5, and bandwidth [BW] = 32 kHz). Then three‐dimensional (3D) MR coronary angiography of the left coronary arteries was obtained using a fast imaging employing steady‐state acquisition (FIESTA) sequence. We subsequently used the MRIG, at a receive‐only mode, to generate intracoronary MR images using FGRE (TR/TE/FA = 7.2 msec/3.5 msec/20°, FOV = 18 × 18cm, thickness = 3 mm, space = 0.5 mm, matrix = 256 × 256, NEX = 0.5, and BW = 32 kHz). Results In all six animals the left main coronary arteries were successfully catheterized. 3D MR imaging displayed left coronary artery branches. Intracoronary MR imaging demonstrated the inflated balloons as a “train track” or a bright, thick ring at different views. Conclusion This study demonstrates the potential of using this newly designed gold/sliver/Nitinol/MP35N‐based, 0.014‐inch MRIG to catheterize coronary arteries and, thus, generate intracoronary MR imaging with balloon inflation. J. Magn. Reson. Imaging 2008;28:515–518. © 2008 Wiley‐Liss, Inc.