C-arm CT with Metal Artifact Reduction Improves Stent-Treated Aneurysm Assessment

Combining high-resolution C-arm CT and Metal Artifact Reduction (MAR) may improve the assessment of aneurysms treated with stent-assisted coil embolization, according to a study1 recently published in the American Journal of Neuroradiology.

The study was designed to evaluate the efficacy of a novel Metal Artifact Reduction prototype software combined with the currently available high spatial-resolution C-arm CT prototype implementation by using an experimental aneurysm model treated with stent-assisted coil embolization.

The researchers created eight experimental aneurysms in 6 swine and performed coil embolization of each aneurysm by using a stent-assisted technique. High-resolution C-arm CT with intra-arterial contrast injection was performed immediately after the treatment. The images were processed with MAR.

Every aneurysm was successfully created and treated with stent-assisted coil embolization. Five neurointerventional specialists reviewed the image quality before and after MAR and found that before MAR, coil loops protruding through the stent lumen were not visualized due to the prominent metal artifacts produced by the coils. These became visible after MAR processing. Contrast filling in the residual aneurysm was also visualized after MAR in every aneurysm. Both the observational (P < .0001) and quantitative (P < .001) analyses showed significant reduction of the metal artifacts after application of the MAR prototype software.

In the study, high-resolution C-arm CT and MAR enabled differentiation of the coil mass, stent, and contrast material on the same image by significantly reducing the metal artifacts produced by the platinum coils.  

Figure: The basilar stem aneurysm showed complete occlusion initially after insertion of a single coil 2.5 mm in diameter: coil compaction and significant aneurysm growth in 6-month follow-up-DSA.2



1. Ykia I, Kambayashia Y, Ikemuraa A, Abea Y. High-Resolution C-Arm CT and Metal Artifact Reduction Software: A Novel Imaging Modality for Analyzing Aneurysms Treated with Stent-Assisted Coil Embolization. AJNR Am J Neuroradiol. 2016 Feb;37(2):317-23. doi: 10.3174/ajnr.A4509. Epub 2015 Sep 10.

2. Flat Panel Detector Angiographic CT for Stent-Assisted Coil Embolization of Broad-Based Cerebral Aneurysms. http://www.ajnr.org/content/28/10/1902/F1.expansion.html