Evaluation of ischemic lesion prevalence after endovascular treatment of intracranial aneurysms, as documented by 3-T diffusion-weighted imaging: a 2-year, single-center cohort study

OBJECTIVE Even though published data exist concerning the prevalence of ischemic lesions detected by diffusion-weighted imaging (DWI) following endovascular treatment of intracranial aneurysms, a single-center cross-evaluation of the different endovascular techniques has been lacking. The authors sought to prospectively evaluate the prevalence and clinical significance of ischemic lesions occurring after endovascular treatment of intracranial aneurysms and to compare the safety and effectiveness of a broad spectrum of currently accepted endovascular techniques in a single-center setting. METHODS This was a prospective cohort study involving consecutive patients treated for intracranial aneurysms exclusively by endovascular means, excluding treatments in the acute rupture phase, in a center featuring an endovascular-only treatment policy for intracranial aneurysms. All patients underwent MRI, including a 3-directional DWI sequence, before treatment, 24 hours postprocedure, and 6 months following endovascular embolization. Selective angiography was performed at 6 months' follow-up. RESULTS From January 2012 through December 2013, 164 aneurysms were treated in 128 consecutive patients. Endovascular techniques included coiling (14.6%), balloon-assisted coiling (20.1%), stent-assisted coiling (3.7%), low-profile stent-assisted coiling, flow diversion (38.4%), and very complex treatments (6.1%) involving 2 stents in Y or T configurations. On postprocedure MRI, the rates of occurrence of new DWI-positive lesions were 64.3% for coiling, 54.5% for remodeling, 61.1% for stent-assisted coiling, 53.7% for flow-diverting stents, and 75% for very complex treatments (p = 0.4962). The 6-month procedure-related morbidity and mortality rates were 6.25% and 0%, respectively. At 6 months' follow-up, 93% of the patients had modified Rankin Scale (mRS) scores of 0-2. Very complex treatments offered a higher complete occlusion rate (100%) than all other techniques (66.7%-88.9%). Age and length of procedure were independent factors for DWI lesion occurrence. The diameter of DWI lesions on 24-hour postprocedure MRI was positively correlated with mRS score at discharge. Among the DWI-positive lesions measuring less than 2 mm in diameter on the 24-hour MRI, 44.12% had regressed at 6 months. CONCLUSIONS Procedure-related DWI lesions are far more often encountered in silent forms than they are clinically evident. They do not seem to be significantly correlated with procedure-related complications, nor do they seem to impair clinical outcome, regardless of the endovascular technique. Small lesions (< 2 mm in diameter) may regress within 6 months. The use of the most adapted technique, in terms of aneurysm configuration, results in significant total occlusion rates, with acceptable safety.