The usefulness of contrast-enhanced subtraction magnetic resonance imaging for detecting endoleaks after endovascular aortic repair with prophylactic intraoperative sac embolization.

Background: Metallic and hyperdense artifacts and T1-shortening substances in the abdominal aortic aneurysm (AAA) sac generated by embolic materials and lipiodol pose challenges in the identification of endoleaks on follow-up computed tomography (CT) or magnetic resonance imaging (MRI).

Purpose: To evaluate the usefulness of contrast-enhanced subtraction MRI (CES-MRI) for detecting endoleaks after endovascular abdominal aortic aneurysm repair (EVAR) with intraoperative AAA sac embolization compared with CE-CT, this study was conducted.

Material and methods: In this study, 28 consecutive patients who underwent EVAR with prophylactic AAA sac embolization were included. All patients underwent CES-MRI and CE-CT to detect endoleaks. The definitive diagnosis of endoleaks was a consensus reading of CE-CT and CES-MRI by two certified radiologists, in addition to angiography or reproducible radiological findings in the observational examination. Analysis was performed to evaluate which examination was better for detecting endoleaks.

Results: The sensitivity, specificity, and area under the curve of CE-CT and CES-MRI according to observer 1 were 50%, 100%, and 0.813 (95% confidence interval [CI] = 0.625-1.00) and 100%, 95%, and 0.997 (95% CI = 0.984-1.00), respectively, and those according to observer 2 were 50%, 100%, and 0.750 (95% CI = 0.514-0.986) and 100%, 95%, and 0.969 (95% CI = 0.903-1.00), respectively. Intolerable artifacts were significantly observed on CE-CT. The severity of the artifacts did not depend on the stent graft on CT and MRI.

Conclusion: Although no significant difference was observed, CES-MRI tended to have better accuracy for endoleak detection in EVAR with intraoperative AAA sac embolization than CE-CT.