abbreviatioNs ACA = anterior cerebral artery; AChA = anterior choroidal artery; ACoA = anterior communicating artery; ARU = aspirin reaction unit; cICA = cavernous segment of the internal carotid artery; DSA = digital subtraction angiography; DWI = diffusion-weighted imaging; ECA = external carotid artery; MCA = middle cerebral artery; mRS = modified Rankin Scale; OKM = O'Kelly and Marotta; PCoA = posterior communicating artery; PRU = P2Y12 reactivity unit; SAH = subarachnoid hemorrhage; VA = vertebral artery. submitted November 22, 2013. accepted October 7, 2014. iNclude wheN citiNg Published online January 6, 2015; DOI: 10.3171/2014.10.JNS132566. disclosure The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. obJect It was initially considered safe for flow-diverting stents to cover the ostia of branching vessels during endovascular procedures for the treatment of intracranial aneurysms. As more recent evidence suggests, however, their use is not always free of ischemic concerns in terms of covered arterial ostia. The authors sought to determine the frequency of silent and clinically evident diffusion-weighted imaging (DWI)-detected abnormalities related to stent placement as a means of elucidating potential clinical risks. methods This is a prospective single-center study on a series of patients with intracranial aneurysms that were treated with flow-diverting stents. All patients systematically underwent an MRI protocol that included DWI before treatment, between 24 and 48 hours postprocedure, and 3 months postembolization. Effectiveness of anticoagulation treatment was assessed for all patients. Lesions seen on DWI were correlated to the parent artery and the side-branch territories and were statistically analyzed in relation to their time of occurrence and clinical presentation. The authors compared the DWI findings in these patients to findings obtained in patients treated with a stent-assisted coiling technique during the same time period. results Over the course of 18 consecutive months, 38 consecutive patients (7 males and 31 females) with 49 intracranial aneurysms were treated using flow-diverting stents. Overall, 81.6% of the DWI spots found remained clinically silent during the follow-up period. Five ischemic clinical complications (13.2%) occurred in the postprocedural period. No statistically significant correlation could be established between DWI spots or aneurysm location and clinical complications or follow-up modified Rankin Scale score at 3 months. The complication rate was 7.8% (n = 3) at the 3-month follow-up, and mortality was 0%. Compared with stent-assisted coiling, use of flow-diverting stents showed a statistically significant correlation with silent DWI findings postintervention. coNclusioNs Lesions seen on DWI resulting from the procedure are far more common than anticipated, but the technique remains safe and effective, providing an interesting alternative for "difficult" aneurysms, regardless of ...