Abstract W P67: High Resolution C-arm Ct and Metal Artifact Removal Software; A Novel Imaging Modality to Analyze Aneurysms Treated With Stent Assisted Coil Embolization

Abstract

Purpose: Stent assisted coil embolization recently became a common treatment strategy for the wide neck aneurysms. Normal digital subtraction angiography (DSA), however, does not allow visualization of the deployed stents. The combination of high resolution C-arm CT (HR C-arm CT) and a novel Metal Artifact Removal software (MAR) enables the visualization of the coil mass, stent, and contrast material with high spatial resolution as well as significant reduction of metal artifacts produced by the platinum coils. In this study, experimental aneurysms were treated with stent assisted coil embolization and image analysis was performed using the HR C-arm CT and MAR. I.V. injection of the contrast to obtain the images was also performed. Methods: A total of 9 experimental aneurysms were created in 5 swine. Endovascular treatment using a stent was performed after the aneurysm creation. HR C-arm CT was performed immediately after the treatment and obtained images were processed with MAR. Intra arterial injection of the diluted contrast (10%) was performed in every swine and intra venous injection (non-diluted) was also performed in 3 swine. Visualization of the residual aneurysms as well as coil loops protruded into the stent lumen was evaluated. Results: Coil loops protruded into the stent lumen, which were not visible before the MAR due to the significant metal artifact, were well visualized after the MAR. Likewise, Contrast filling into the residual aneurism was observed after the MAR in every aneurysm. Intravenous injection of the contrast material reproduced similar image quality as compared to the intra arterial injections. Conclusions: The combination of the HR-Carm CT and MAR enables the differentiation of the coil mass, stent and contrast material by markedly reducing the metal artifact produced by the coils. This novel image modality may contribute to the evaluation of aneurysms treated with stent assisted coil embolization.