Yu Bu Lee , Yoo Joo Choi , Myoung Hee Kim

The KIPS Transactions:PartA, Vol. 14, No. 2, pp. 77-84, Apr. 2007
10.3745/KIPSTA.2007.14.2.77,   PDF Download:

Abstract

The intima－media thickness (IMT) of the carotid artery from B－mode ultrasound images has recently been proposed as the most useful index of individual atherosclerosis and can be used to predict major cardiovascular events. Ultrasonic measurements of the IMT are conventionally obtained by manually tracing interfaces between tissue layers. The drawbacks of this method are the inter－ and intraobserver variability and its inefficiency. In this paper, we present a multiresolution snake method combined with the dynamic programming, which overcomes the various noises and sensitivity to initialization of conventional snake. First, an image pyramid is constructed using the Gaussian pyramid that maintains global edge information with smoothing in the images, and then the boundaries are automatically detected in the lowest resolution level by minimizing a cost function based on dynamic programming. The cost function includes cost terms which are representing image features and geometrical continuity of the vessel interfaces. Since the detected boundaries are selected as initial contour of the snake for the next level, this automated approach solves the problem of the initialization.Moreover, the proposed snake improves the problem of converging to the local minima by defining the external energy based on multiple image features. In this paper, our method has been validated by computing the correlation between manual and automatic measurements.This automated detection method has obtained more accurate and reproducible results than conventional edge－detection by considering multiple image features.

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