Nonenhanced MRI Planning for Endovascular Repair of Abdominal Aortic Aneurysms: Comparison With Contrast-Enhanced CT Angiography

Background: To assess whether noncontrast-enhanced magnetic resonance imaging (NC-MRI) is an alternative to contrast-enhanced computed tomography angiography (CTA) for aortoiliac measurements before endovascular abdominal aortic aneurysm repair (EVAR). Methods: This study encompasses 30 patients admitted for elective EVAR (27 men and 3 women). Two expert readers (vascular radiologist and vascular surgeon) reviewed CTA images in consensus and chose the proper endograft for each patient. Subsequently, a vascular radiologist and a resident radiologist (observer 1 and 2) reviewed CTA and NC-MRI examinations in a double-blind way and completed standard measurements. The interobserver and intermodality agreement was calculated by intraclass correlation coefficients (ICCs). Furthermore, the correlation between the endograft size chosen by the first pair and the second pair of observers was evaluated. Results: Concerning all measurements, no significant difference was found. Both CTA and NC-MRI angiographic measurements showed strong correlation. Interobserver ICCs for CTA and NC-MRI showed ranges of 0.62 to 0.99 (mean: 0.92) and 0.56 to 0.99 (mean: 0.91); intermodality ICCs for observer 1 and 2 showed ranges of 0.64 to 0.99 (mean: 0.92) and 0.56 to 0.99 (mean: 0.92). The CTA and NC-MRI vascular measurements correlated strongly, except for both external iliac artery diameters. The choice of stent size was always the same between the 2 observers; furthermore, graft size was always in agreement with that selected prospectively. Conclusion: Computed tomography angiography remains the standard of reference for EVAR planning; NC-MRI can be an option for patients with contraindications for CTA, in particular those with renal impairment.