Ultrasmall Superparamagnetic Iron Oxide-enhanced Magnetic Resonance Imaging of Abdominal Aortic Aneurysms–A Feasibility Study

Abstract

Objectives Abdominal aortic aneurysms (AAAs), being predominantly atherosclerotic in nature, have underlying inflammatory activity. As it is well established that ultrasmall superparamagnetic iron oxide (USPIO) particles accumulate in the macrophages within atheromatous lesions, USPIO-enhanced magnetic resonance (MR) imaging can be potentially effective in the quantification of the associated inflammatory processes. Methods A total of 14 patients underwent USPIO-enhanced MR imaging using a 1.5T-MR system. Quantitative T 2* and T 2 relaxation time data were acquired before and 36 h after UPSIO infusion at identical AAA locations. The pre- and post-USPIO-infusion relaxation times (T 2 ∗ and T 2) were quantified and the correlation between pre- and post-USPIO infusion T 2* and T 2 values was investigated. Results There was a significant difference between pre- and post-infusion T 2* and T 2 values (both respective p-values = 0.005). A significant correlation between T 2* and T 2 values post-USPIO infusion was observed ( r = 0.90, p < 0.001), which indicates USPIO uptake by the aortic wall. Conclusions Aortic wall inflammation using USPIO-enhanced MR imaging is feasible. Use of quantitative T 2 and T 2* pulse sequences provides a quantitative method for assessing USPIO uptake by the aortic wall.