Endovascular coils mimicking accidental ingestion of a dental-related foreign body in radiographic imaging

If a foreign body is seen on chest or abdominal radiographs, accidental aspiration or ingestion of a dental-related foreign body may be suspected. This report describes a case in which vascular embolization coils seen on radiography were suspected to represent a swallowed dental prosthesis. A 72-year-old man with a history of endovascular embolization of portosystemic shunt was admitted for mandibular fracture. On hospital day 2, a foreign body was noted on chest radiographs taken to confirm pleural effusion. No foreign body had been evident on radiographs of the same area the previous day. The foreign body was suspected to be a dental prosthesis, but intraoral examination ruled out this possibility, and the foreign body turned out to be metal coils used to embolize the shunt. Dentists and oral surgeons should be aware that medical devices such as vascular embolization coils can produce images similar to a dental-related foreign body on chest or abdominal radiographs, and dental-related foreign body ingestion or aspiration should be considered in the differential diagnosis.

Lagrangian Trajectory Simulation of Platelets and Synchrotron Microtomography Augment Hemodynamic Analysis of Intracranial Aneurysms Treated With Embolic Coils

As frequency of endovascular treatments for intracranial aneurysms increases, there is a growing need to understand the mechanisms for coil embolization failure. Computational fluid dynamics (CFD) modeling often simplifies modeling the endovascular coils as a homogeneous porous medium (PM), and focuses on the vascular wall endothelium, not considering the biomechanical environment of platelets. These assumptions limit the accuracy of computations for treatment predictions. We present a rigorous analysis using X-ray microtomographic imaging of the coils and a combination of Lagrangian (platelet) and Eulerian (endothelium) metrics. Four patient-specific, anatomically accurate in vitro flow phantoms of aneurysms are treated with the same patient-specific endovascular coils. Synchrotron tomography scans of the coil mass morphology are obtained. Aneurysmal hemodynamics are computationally simulated before and after coiling, using patient-specific velocity/pressure measurements. For each patient, we analyze the trajectories of thousands of platelets during several cardiac cycles, and calculate residence times (RTs) and shear exposure, relevant to thrombus formation. We quantify the inconsistencies of the PM approach, comparing them with coil-resolved (CR) simulations, showing the under- or overestimation of key hemodynamic metrics used to predict treatment outcomes. We fully characterize aneurysmal hemodynamics with converged statistics of platelet RT and shear stress history (SH), to augment the traditional wall shear stress (WSS) on the vascular endothelium. Incorporating microtomographic scans of coil morphology into hemodynamic analysis of coiled intracranial aneurysms, and augmenting traditional analysis with Lagrangian platelet metrics improves CFD predictions, and raises the potential for understanding and clinical translation of computational hemodynamics for intracranial aneurysm treatment outcomes.

Testing the Medina embolization device in experimental aneurysms

OBJECTIVE

The Medina embolization device (MED) is a novel, braided self-expanding endovascular device designed to occlude aneurysms by constructing an in situ intrasaccular flow diverter. Although a single device can be positioned at the neck of simple spherical in vitro aneurysms, the best way to occlude more complex in vivo aneurysms (using multiple MEDs or a combination of MEDs and platinum coils) is currently unknown.

METHODS

Fifty-two aneurysms of 3 different types were created in 31 canines, yielding 48 patent aneurysms. Treatments were randomly allocated by drawing lots: group 1, MEDs alone (n = 16); group 2, MEDs plus standard platinum coils (n = 16); and group 3, control aneurysms treated with coils alone (n = 16). Angiographic results were scored and compared immediately following treatment completion and at 3 months. Specimens were photographed and the extent of neointimal closure of the aneurysmal neck scored, followed by histopathological analyses.

RESULTS

Angiographic scores of 0 or 1 (occlusion or near occlusion) were initially obtained in 2 of 16 (12.5%, 95% CI 1.6%-38.3%) group 1 (MEDs alone), 3 of 16 (18.7%, 95% CI 4%-45.6%) group 2 (MEDs plus coils), and 10 of 16 (62.5%, 95% CI 35.4%-84.8%) group 3 (coils alone) aneurysms (p = 0.005). At 3 months, scores of 0 or 1 were found in 11 of 16 (68.7%, 95% CI 41.3%-89.0%) group 1, 9 of 16 (56.2%, 95% CI 29.9%-80.2%) group 2, and 8 of 16 (50%, 95% CI 24.7%-75.3%) group 3 aneurysms (p = 0.82). Neointimal scores were similar for the 3 treated groups (p = 0.66).

CONCLUSION

Endovascular treatment of experimental aneurysms with MEDs or MEDs and coils showed angiographic occlusion and neointimal scores at 3 months that were similar to those achieved with standard platinum coiling.