The Effect of Magnetic Resonance Imaging on Stainless Steel Z-stent Based Abdominal Aortic Prostheses

Jade Hiramoto, MD, Linda Reilly, MD, Darren Schneider, MD, Herman Skorobogaty, MD, Jospeh Rapp, MD and Timothy Chuter, MD
UCSF, Division of Vascular Surgery,San Francisco, CA

Objective: To assess the effects of magnetic resonance imaging (MRI) on stainless steel Z-stent based abdominal aortic prostheses.
Methods: From 6/96 to the present, 550 patients underwent endovascular repair of an infrarenal abdominal aortic aneurysm (AAA) at a single academic institution using a stainless steel Z-stent based abdominal aortic prosthesis. Routine patient follow-up included computed tomography (CT) scans and abdominal plain films at 1, 6, and 12 months postoperatively, 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 participate in the study and underwent MRI at a mean interval of 679 days (range 3 - 2179 days) after stent-graft implantation. Eight of 17 patients underwent brain MRI, while 9 of 17 underwent MRI of the abdomen, pelvis, or spine. In all cases, the magnetic field strength was < 1.5 Tesla. No patients experienced any symptoms of abdominal or back pain during or after the MRI. Comparison of pre- and post- MRI CT scans (available in 13 of 17 patients) and abdominal x-rays showed no change in stent graft structure, position, or function in any of these patients, at an average of 506 days after MRI.
Conclusions: Based on this limited experience, MRI has no discernable effect on the structure, position, or function of stainless steel Z-stent based abdominal aortic prostheses.