Contrast-Enhanced MRA Used to Analyze Intracranial Aneurysms Treated by Flow-Diverting Stents

August 2, 2017—Long-term results of intracranial aneurysms treated with flow-diverting stents, with a focus on the usefulness of contrast-enhanced MRA, were reported by Maximilian Patzig, MD, et al online ahead of print in CardioVascular and Interventional Radiology.

The investigators analyzed interventions and follow-up imaging of patients with aneurysms treated by flow-diverting stents—including the Pipeline embolization device (Medtronic), the Silk device (Balt Extrusion), and the FRED flow-redirection endoluminal device (MicroVention Terumo)—without additional coiling.

All MRI scans included dedicated two-phase contrast-enhanced MRA. The investigators used MRI and digital subtraction angiography (DSA), where available, to evaluate aneurysm occlusion rates, aneurysm sac size, and complications. They graded the ability of contrast-enhanced MRA to depict aneurysm occlusion and stent patency on a three-point scale.

As summarized in CardioVascular and Interventional Radiology, the study included 25 patients with 102 MRI scans. The median duration of follow-up was 830 days. Aneurysm occlusion rates were 52% at 3 months (10 of 19 patients), 72% at 6 months (18/25), and 84% overall (21/25). Shrinkage of the aneurysm sac was found in 19 patients (76%) and in 12 patients to < 50% of the original size (48%). Contrast-enhanced MRA assessability of aneurysmal occlusion was graded as "good" in all cases. When compared to DSA (18 cases), contrast-enhanced MRA had a sensitivity of 100% and specificity of 91% regarding aneurysm remnant detection. The investigators noted that assessability of the stent lumen varied and was limited in most cases.

Flow-diverter treatment achieves high occlusion rates and can cause major aneurysm shrinkage. Contrast-enhanced MRA is highly valuable regarding imaging of the aneurysmal sac; however, there are limitations regarding the assessability of the stent lumen on contrast-enhanced MRA, concluded the investigators in CardioVascular and Interventional Radiology.