Stochastic region competition algorithm for Doppler sonography segmentation.

Purpose: A probabilistic image segmentation algorithm called stochastic region competition is proposed for performing Doppler sonography segmentation. Methods: The image segmentation is conducted by maximizing a posteriori that models histogram likelihood, gradient likelihood, and a spatial prior. The optimization is done by a modified expectation and maximization (EM) method that aims to improve computation efficiency and avoid local optima. Results: The algorithm was tested on 155 color Doppler sonograms and compared with manual delineations. The qualitative assessment shows that our algorithm is able to segment mass lesions under the condition of low image quality and the interference of the color-encoded Doppler information. The quantitative assessment analysis shows that the average distance between the algorithm-generated boundaries and manual delineations is statistically comparable to the variability of manual delineations. The ratio of the overlapping area between the algorithm-generated boundaries and manual delineations is also comparable to that between different sets of manual delineations. A reproductivity test was conducted to confirm that the result is statistically reproducible. Conclusions: The algorithm can be used to perform Doppler sonography segmentation and to replace the tedious manual delineation task in clinical application. [ABSTRACT FROM AUTHOR]