PurposeRapid revascularization in emergent large vessel occlusion with endovascular embolectomy has proven clinical benefit. We sought to measure device–clot interaction as a potential mechanism for efficient embolectomy.MethodsTwo different radiopaque clot models were injected to create a middle cerebral artery occlusion in a patient-specific vascular phantom. A radiopaque stent retriever was deployed within the clot by unsheathing the device or a combination of unsheathing followed by pushing the device (n=8/group). High-resolution cone beam CT was performed immediately after device deployment and repeated after 5 min. An image processing pipeline was created to quantitatively evaluate the volume of clot that integrates with the stent, termed the clot integration factor (CIF).ResultsThe CIF was significantly different for the two deployment variations when the device engaged the hard clot (p=0.041), but not the soft clot (p=0.764). In the hard clot, CIF increased significantly between post-deployment and final imaging datasets when using the pushing technique (p=0.019), but not when using the unsheathing technique (p=0.067). When we investigated the effect of time on CIF in the different clot models disregarding the technique, the CIF was significantly increased in the final dataset relative to the post-deployment dataset in both clot models (p=0.004–0.007).ConclusionsThis study demonstrates in an in vitro system the benefit of pushing the Trevo stent during device delivery in hard clot to enhance integration. Regardless of delivery technique, clot–device integration increased in both clot models by waiting 5 min.

BackgroundRates of durable aneurysm occlusion following coil embolization vary widely, and a better understanding of coil mass mechanics is desired. The goal of this study is to evaluate the impact of packing density and coil uniformity on aneurysm permeability.MethodsAneurysm models were coiled using either Guglielmi detachable coils or Target coils. The permeability was assessed by taking the ratio of microspheres passing through the coil mass to those in the working fluid. Aneurysms containing coil masses were sectioned for image analysis to determine surface area fraction and coil uniformity.ResultsAll aneurysms were coiled to a packing density of at least 27%. Packing density, surface area fraction of the dome and neck, and uniformity of the dome were significantly correlated (p<0.05). Hence, multivariate principal components-based partial least squares regression models were used to predict permeability. Similar loading vectors were obtained for packing and uniformity measures. Coil mass permeability was modeled better with the inclusion of packing and uniformity measures of the dome (r2=0.73) than with packing density alone (r2=0.45). The analysis indicates the importance of including a uniformity measure for coil distribution in the dome along with packing measures.ConclusionsA densely packed aneurysm with a high degree of coil mass uniformity will reduce permeability.

BACKGROUND AND PURPOSE:Recently, the use of stents to assist in the coiling and repair of wide-neck aneurysms has been shown to be highly effective; however, the effect of these stents on the RC of the parent vessel has not been quantified. The purpose of this study was to quantify the effect of intracranial stenting on the RC of the implanted artery using 3D datasets.

BACKGROUND AND PURPOSE:Intracranial aneurysms treated by coiling have a risk for recurrence, requiring surveillance imaging. MRA has emerged as an attractive technique for postcoiling aneurysm imaging. Previous research has evaluated MR imaging artifacts of the coil mass in vitro. Our aim in this study was to evaluate MR imaging artifacts of coiled aneurysms in vivo with time.

SUMMARY:We report a novel model of arterial tortuosity in the porcine brachial artery for testing of endovascular devices in the flexed forelimb position. This provides an ideal vascular territory for an in vivo assessment of guidewires, microcatheters, and endovascular implants because it closely mimics the challenging curvature at the carotid siphon.ABBREVIATIONS AC ϭ average curvature; 3DRA ϭ 3D rotational angiography; CCA ϭ common carotid artery A dvances in interventional neuroradiology are reshaping the treatment paradigms and have facilitated the development of a wide array of endoluminal techniques for vascular lesions that were earlier only approachable neurosurgically. The ICA siphon is extremely relevant for intracranial access, because its tortuosity and bony encasement can be a significant impediment for guidewires and microcatheters to gain intracranial access and may also preclude the delivery of devices like intracranial stents.As newer devices are developed, they are first evaluated in vitro and in cadaveric models. Although indispensible, these can only assess the mechanical and structural responses. For a realistic simulation of the critical vessel viscoelastic and physiologic responses, an in vivo assessment of endovascular devices is crucial. We describe a porcine brachial artery tortuosity model to provide a challenging vascular territory for endovascular device testing. TECHNIQUEThree Yorkshire swine (male; mean weight, 47 kg) were used for the purposes of our study. All procedures were conducted in accordance with the protocol approved by the Institutional Animal Care and Use Committee of University of Massachusetts Medical School. The animals were premedicated with glycopyrrolate (0.01 mg/kg). Anesthesia was induced by an intramuscular injection of tiletamine (Telazol, 5 mg/kg), ketamine (2.5 mg/kg), and xylazine (2.5 mg/kg) and maintained with mechanical ventilation of oxygen containing 1%-3% isoflurane. Continuous monitoring of the heart rate, respiration, oxygen saturation level (pulse oximetry), end-tidal carbon dioxide, and temperature allowed real-time assessment of the physiologic status of the animal. A 6F hemostatic introducer was placed in the right femoral artery by using a modified Seldinger technique following a cut-down. The introducer was secured in place, with the distal aspect of the femoral artery ligated. A 6F catheter was then advanced over the guidewire under x-ray fluoroscopy. Animal PositioningSelective intra-arterial digital subtraction angiography of the right and left subclavian arteries was performed in both the extended and the flexed forelimb position of the swine by using table restrainers, as illustrated in Fig 1A, -B. The guide catheter was selectively positioned in the brachial branch of the subclavian artery. A selective intra-arterial injection of the contrast agent (Iopamidol, Isovue; Bristol Myers Squibb, Princeton, New Jersey) was administered with a power injector at an injection rate of 2.5 mL/s for 11.2 seconds with a 7-second delay to acquire a 3...