AJNR Editor-in-Chief
Mauricio Castillo

The next generation of devices to treat intracranial aneurysms, flow diverters, is receiving considerable attention in the literature and clinical practice. As such, we decided that recent articles published in AJNR would serve as an excellent launching pad for our new electronic AJNR News Digest. This monthly e-publication will highlight the latest techniques and technology in neuroimaging in a simple, friendly format similar to that now used by the major news and media outlets, and perfectly adapted to tablet browsing.

Wide-neck, giant, fusiform, or very small aneurysms are still a challenge to treat with current endovascular techniques. In April 2012, based on the results of the PUFS study, the FDA approved the use of Pipeline devices for treatment of wide-neck aneurysms of the proximal ICA. Pipelines reroute the flow into the parent artery, changing the hemodynamics away from intra-aneurysmal circulation and inducing progressive thrombosis of the aneurysm. Despite the high rate of aneurysm occlusions, complications such as delayed rupture and more surprising distal intra-parenchymal hemorrhage have been described and, thus, questions concerning long-term outcomes remain. Remote intra-parenchymal hemorrhage appears to be directly associated with the flow-diversion process as distal hemorrhages are not seen in classic stenting and embolization procedures. Published reports speculate on the likelihood that flow-diverting devices could decrease segmental compliance of the stented blood vessels and modify the blood pressure waveforms transmitted to distal cerebral vasculature or result in a thrombus-mediated weakening of the aneurysm walls; however, no

acceptable level of evidence to corroborate either has been obtained. Besides delayed events, overall reported procedural and peri-procedural morbidity/mortality, along with the high rate of complete or near-complete occlusion, make flow-diverting devices promising and exciting tools in the treatment of complex large or fusiform aneurysms.

Nevertheless, the development of endovascular mechanical devices is based on the concept that vascular lesions are related to luminal disorders (flux and hemodynamics) and makes little of wall dysfunctions and of processes occurring in the extraluminal space. Development of biologic agents targeting the aneurysm walls and their environment could in the future be valuable approaches to the treatment of vascular lesions.

Here, we briefly highlight 5 related articles and an editorial. Access to the full-length articles is available through www.ajnr.org. In this first issue of AJNR News Digest, the authors of the quoted articles offer short thoughts on the importance of their publications. While AJNR publishes mid-month, this News Digest should arrive in your in-box at the start of each new month. Please let us know your thoughts about it. We welcome suggestions for future topics.

Image modified from: Saatci I, Yavuz K, Ozer C, et al. Treatment of Intracranial Aneurysms Using the Pipeline Flow-Diverter Embolization Device: A Single-Center Experience with Long-Term Follow-Up Results.