Use of a Combined MR Imaging and Interventional Radiology Suite for Intraprocedural Monitoring of Uterine Artery Embolization

Purpose: The optimal embolic endpoint for uterine artery embolization (UAE) is unknown. It is difficult to quantify substasis endpoints with the use of conventional x-ray interventional radiology (IR) guidance. Although magnetic resonance (MR) imaging can detect perfusion changes, intraprocedural perfusion changes within targeted uterine leiomyomas and the remaining uterine wall remain unknown. A hybrid MR/IR unit was used to test the hypothesis that MR imaging can detect changes in uterine perfusion-dependent signal enhancement immediately after UAE. Materials and Methods: In this prospective study, UAE was performed in a hybrid MR/IR unit in women with symptomatic uterine leiomyomas. This MR/IR unit contains a wide-bore 1.5-T MR scanner connected by a sliding table to an adjacent x-ray digital subtraction angiography unit. Gadolinium-enhanced MR imaging was performed before and after UAE. Relative signal-to-noise ratio (SNR) was measured within each tumor and the adjacent uterine wall, and mean relative SNR changes were compared before and after UAE with the paired t test (α = 0.05). Results: UAE was technically successful in all six women, in whom 10 tumors were assessed (seven intramural, two submucosal, one subserosal). Mean relative SNR of the tumors before UAE was 62.2 ± 25.0 and was reduced to 41.1 ± 17.7 after UAE (P < .01). Mean relative SNR of the adjacent uterine wall was 64.2 ± 14.3 before UAE and decreased to 28.8 ± 14.9 after UAE (P < .01). Conclusions: Immediate reductions in perfusion-dependent enhancement in targeted uterine leiomyomas and the adjacent uterine wall can be detected during UAE with the use of a hybrid MR/IR unit. Further studies are now warranted to compare long-term clinical outcomes versus immediate changes in perfusion at the time of UAE.