Elisa Pomero, Presenter: Nothing to Disclose

Arnaud Flores, Abstract Co-Author: Nothing to Disclose

Clelia Billon Grand, Abstract Co-Author: Nothing to Disclose

Francoise Cattin, Abstract Co-Author: Nothing to Disclose

Alessandra Biondi MD, Abstract Co-Author: Consultant, Stryker Corporation Consultant, Covidien AG

New devices in the treatment of intracranial aneurysms include intra-aneurysmal flow disrupters. The MR imaging of these new devices has not been reported. The purpose of our study is to report MR findings in a consecutive series of patients treated with the LUNATM Aneurysm Embolization System, a new intra-aneurysmal self-expandable, round-ovoid flow disrupter implant.

A total of 12 unruptured aneurysms were treated in 12 patients. Ten lesions were located in the anterior circulation and 2 lesions were in the posterior circulation. In addition, all patients underwent 24 hours DSA control and 24-48 hours MR study including evaluation of silent lesions. Three months MR FU was available in all patients and 1 year MR FU in 11. MR studies were performed on a 3Tesla MR unit. Our MR protocol included DWI, T2WI FLAIR, coronal TIWI, axial PDWI, axial T2WI, Angio-MR 3D-TOF. In all patients, 1 year MR FU included also Inhanced 3D Velocity with Gadolinium injection. Follow-up included Digital Subtraction Angiography (DSA) at 6 and 12 months. Results were compared with the angiographic findings.

Immediate angiographic occlusion was achieved in 3 cases, near complete in 3 and incomplete occlusion in 6. The LUNATM device presents a marked signal void in all sequence. Evaluation of aneurysm occlusion on MR images without contrast injection showed a good correlation with angiographic findings in 80% of cases. The thrombosed aneurysm sac was evident on PDWI and T2WI sequences. In patients with an angiographically thrombosed aneurysm, T1 WIs showed a hyperintense halo in 91% of cases corresponding to the the thrombosed space between the device and the anevrysm wall. A “crescent moon sign” due to the device shape and related to persistent flow at the base of the aneurysm was seen in TOF sequences. Residual or recurrent aneurysm (20 % ) could be visualized on the  MR study only after contrast injection suggesting that LUNATM device masks the slow flow signal.  

Although DSA FU is mandatory, preliminary results suggest that contrast enhanced MRI is an efficient tool in assessing the occlusion of the aneurysms treated by the LUNATM .

To our knowledge, there are no MR studies specifically dealing with intra-aneurysmal flow disrupter devices. We report our experience in MRI and DSA correlation in patients treated with LUNATM .

Pomero, E, Flores, A, Billon Grand, C, Cattin, F, Biondi, A, MR Imaging in Intracranial Aneurysms Treated by Intra-aneurismal Flow Disrupter: the LUNA™ Aneurysm Embolization System (AES).  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13021642.html