Fully Automatic Extraction of Carotid Artery Contours from Ultrasound Images

SUMMARY In this paper, we propose a fully automatic method forextracting carotid artery contours from ultrasound images based on an ac-tive contour approach. Several contour extraction techniques have beenproposed to measure carotid artery walls for early detection of atheroscle-rotic disease. However, the majority of these techniques require a certaindegree of user interaction that demands time and effort. Our proposal au-tomatically detects the position of the carotid artery by identifying bloodflow information related to the carotid artery, and an active contour modelis employed that uses initial contours placed in the detected position. Ourmethodalsoappliesaglobalenergyminimizationschemetotheactivecon-tour model. Experiments on clinical cases show that the proposed methodautomatically extracts the carotid artery contours at an accuracy close tothat achieved by manual extraction. key words: active contour model, ultrasound, carotid artery, plaque 1. Introduction According to data from the World Health Organization(WHO), cardiovascular disease (CVD) is the global numberone cause of death[1]. The WHO reports that an estimated17.3 million people died of CVDs in 2008, accounting for30% of all global deaths, and predicts that the number ofdeaths from CVDs will rise to 23.3 million by 2030. Theearliest manifestation of the CVDs is atherosclerosis, whichcauses carotid arterial wall thickening and atheroscleroticplaques. Early detection of atherosclerotic disease is thusvery important. Several imaging modalities are currentlyused for assessing the health of arteries, including magneticresonance imaging (MRI), computed tomography (CT), andultrasound. Ultrasound is favored as a non-invasive and in-expensive modality, and is widely used for screening androutine examinations in clinical practice.The most widely used indicator of atherosclerotic dis-ease is the intima-media thickness (IMT) of the carotidartery walls[2],[3]. Using ultrasound, IMT can be mea-sured by sonographers on longitudinal B-mode images. Ingeneral, sonographers manually trace the lumen-intima (LI)interface and media-adventitia (MA) interface. IMT is thenrecorded as the distance between the traced lines.