A fully automated method using active contours for the evaluation of the intima-media thickness in carotid US images

S. Petroudi,M. Pantziaris,M. Pattichis,C. Pattichis,C. Loizou

doi:10.1109/iembs.2011.6091986

S. Petroudi, M. Pantziaris + Show 3 more

Open Access

https://doi.org/10.1109/iembs.2011.6091986

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Abstract

The thickness of the intima-media complex (IMC) of the common carotid artery (CCA) wall is important in the evaluation of the risk for the development of atherosclerosis. This paper presents a fully automated algorithm for the segmentation of the IMC. The segmentation of the IMC of the CCA wall is important for the evaluation of the intima media thickness (IMT) on B-mode ultrasound images. The presented algorithm is based on active contours and active contours without edges. It begins with image normalization, followed by speckle removal. The level set formulation of Chan and Vese using random initialization provides a segmentation of the CCA ultrasound (US) images into different distinct regions, one of which corresponds to the carotid wall region above the lumen whilst another corresponds to the carotid wall region below the lumen and includes the IMC. The results of the corresponding segmentation combined with anatomical information provide a very accurate outline of the lumen-intima boundary. This outline serves as an excellent initialization for segmentation of the IMC using parametric active contours. The method lends itself to the development of a fully automated method for the delineation of the IMC. The mean and standard deviation of the thickness of the automatically segmented regions are 0.65 mm +/-0.17 mm and the corresponding values for the ground truth IMT are 0.66 mm +/-0.18 mm. The Wilcoxon rank sum test shows no significant difference.

Highlights

Cardiovascular Disease (CVD) is one of the most common causes of death in the western world and stroke the most common cause of disability in women
intima media thickness (IMT) can be measured through segmentation of the intima media complex (IMC), which corresponds to the intima and media layers of the arterial wall
The active contours without edges algorithm [13] is used to segment the US images into the lumen and the carotid wall, and the segmentation results are combined with standard anatomical information to evaluate the needed parameters for accurate segmentation of the IMC at different stages of the algorithm

Summary

Introduction

Cardiovascular Disease (CVD) is one of the most common causes of death in the western world and stroke the most common cause of disability in women. The main pathophysiological mechanism leading to CVD is the development of atherosclerosis: the degeneration of the arterial walls though lipid and other blood-borne material on vascular territories throughout the body. Carotid intima media thickness (IMT) is a measure of early atherosclerosis which can be evaluated non-invasively and with low cost, using high-resolution ultrasound (US). It is the distance between the lumen-intima and the media-adventitia interfaces; and can be seen in US as the double line pattern on both walls of the longitudinal images of the common carotid artery (CCA) [1]. IMT can be measured through segmentation of the intima media complex (IMC), which corresponds to the intima and media layers (see Fig. 1) of the arterial wall. Determination of the IMC boundaries is a complicated task, as the IMC is a thin, relatively low contrast structure, that can be obstructed by ultrasound artifacts, may appear differently due to either different imaging angles and/or differences in anatomy and deteriorates with age [4]

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