Detection of Left Ventricular Myocardial Contours from Ischemic Cardiac MR Images

Quantitative evaluation of cardiac function from cardiac magnetic resonance (CMR) images requires the identification of the myocardial walls. This generally requires the clinician to view the image and interactively trace the contours. The myocardial wall of the left ventricle in CMR images, obtained from subjects having serious diseases, is obscure, henceforth, its detection is a tough task. In this paper, an approach to outlining the left ventricular contour is proposed. The utilization of a random walk approach is shown in order to extract the blood pool boundary or endocardium (the inner side of the left ventricular myocardial wall). Inaccurate segmentation is resulted, while applying the approach to ischemic CMR images, because this type of images bear multilabeled blood pool and the manual seed(s) selection in these images introduces variability in the results. In view of this, the paper presents two modifications in the algorithm: (1) automatic seed(s) selection and (2) introduction of Laplacian of difference of Gaussian weighting function. Subsequently, a modified version of an active contour method is implemented to extract the epicardium (the outer side of the left ventricular myocardial wall). This outer contour is achieved by taking the blood pool boundary as its initial contour. Basically, this method is based on active contour without edges. Promising experimental results in CMR images demonstrate the potentials of our approach.