The effect of magnetic resonance imaging on stainless-steel Z-stent–based abdominal aortic prosthesis
Presented at the Twenty-First Annual Meeting of the Western Vascular Society, La Jolla, Calif, Sept 16-19, 2006.
Received 16 September 2006; accepted 8 November 2006. published online 26 January 2007.
Objective
To assess the effects of magnetic resonance imaging (MRI) on stainless-steel Z-stent–based abdominal aortic prostheses.
Methods
From June 1996 to December 2005, 550 patients underwent endovascular repair of an infrarenal abdominal aortic aneurysm at a single academic institution by using a stainless-steel Z-stent–based abdominal aortic prosthesis. Routine patient follow-up included computed tomography scans and abdominal plain films at 1, 6, and 12 months after surgery and yearly thereafter. Although patients were specifically instructed not to undergo MRI, retrospective review identified 22 patients (4%) who underwent MRI after stent-graft implantation.
Results
Seventeen of 22 patients consented to have their records reviewed as part of this study and underwent MRI at a mean interval of 669 days (range, 3-2179 days) after stent-graft implantation. Eleven patients underwent implantation of Zenith bifurcated stent grafts, and six had custom-made uni-iliac stent grafts. These patients underwent a total of 20 MRI studies—10 of the brain/neck and 10 of the abdomen, pelvis, or spine. In all cases, the magnetic field strength was 1.5 T or less. No patient experienced any symptoms of abdominal or back pain during or after the MRI. Comparison of the pre- and post-MRI computed tomography scans (available in 15 of 17 patients) and abdominal radiographs showed no change in stent-graft structure, position, or function in any of these patients and no increase in abdominal aortic aneurysm diameter in any patient at an average of 899 days after MRI.
Conclusions
On the basis of this limited experience, MRI has no discernible effect on the structure, position, or function of stainless-steel Z-stent–based abdominal aortic prostheses.
Division of Vascular Surgery, University of California–San Francisco, San Francisco, Calif.
Reprint requests: Jade S. Hiramoto, MD, UCSF Division of Vascular Surgery, 400 Parnassus Ave, A-581, San Francisco, CA 94143-0222.
Competition of interest: Dr Chuter has licensed patents to Cook, Inc, manufacturers of catheters, guidewires, and the Zenith stent graft.
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