P015] Contrast of dual energy CT in carotid artery analysis, a phantom study

Abstract

Purpose Dual Energy Computed Tomography (DECT) has high tissue characterization properties compared to traditional computed tomography (CT). In CT angiography (CTA), this property is important for analyzing the stage of atherosclerosis. The goal of this project was to study the significance of DECT technology in CTA especially for atherosclerosis diagnosis. Methods A self-made phantom was designed to model the neck area and carotid arteries. Main organs in the neck area were built by using various materials. Agar was used to mimic soft tissue, cattle bone to spine, empty plastic bottle to trachea, oil to lipid, and two small plastic tubes to mimic left and right carotid arteries. A human tooth was placed in the phantom to study the artefacts. The artery tubes contained water and diluted iodine as contrast agent. A 300 mg/ml iodine concentration was diluted to 6 mg/ml to meet the image contrast obtained in arteries of the patients using SECT CTA procedure. The phantom was then scanned with CTA SECT and DECT protocols. Images were analyzed using image processing tool. Results Image resulted from DECT show changes in material contrast compared to SECT. The contrast agent, bone, air and tooth have lower HU when scanned with DECT, while water, oil and agar show increased HU values. Improvement in oil contrast is highly visible on DECT image. The artefact from beam hardening effect caused by tooth and bone was reduced significantly by the DECT technology. Conclusions DECT seems to produce better image quality for studying carotid arteries than SECT. DECT images have higher material contrast and lower artefact from beam hardening effect. Both properties are important in atherosclerosis analysis.