Three-dimensional MR angiography in imaging platinum alloy stents

Purpose: To evaluate visualization inside platinum stents with three-dimensional contrast-enhanced magnetic resonance angiography (CE-MRA). Materials and Methods: Breath-hold three-dimensional gadolinium (Gd) MRA was performed on 18 patients with 22 platinum stents in the renal (n = 18), celiac (n = 1), superior mesenteric (n = 1), and iliac (n = 2) arteries. Electronic calibers were used to measure the lumen diameter within the stent and just distal to the stent to calculate percent stenosis. MRA accuracy was determined from the difference between percent stenosis measured on MRA and digital subtracted angiography (DSA). The patients were imaged at flip angles of 45degrees, 60degrees, 75degrees, 90degrees, and 150degrees. Results: MRA demonstrated the stent lumen in all of the patients, with a mean difference between MRA and DSA of 21%. For stents oriented parallel to B-0 (iliac arteries) the difference was only 10%, as compared to 22% for stents perpendicular to B-0. The flip angle with the best agreement between MRA and DSA was 75degrees (16%). Conclusion: The lumen of a platinum stent can be imaged with three-dimensional CE-MRA, although grading of restenosis has limited accuracy. The best results were obtained with a flip angle of 75degrees and for stents in the iliac arteries parallel to B-0. (C) 2004 Wiley-Liss, Inc.