MRI Segmentation of Left-Ventricle using Shape and Distribution Priors

Post date: Mar 21, 2011 9:45:55 AM

This study applies the convex relaxation approach to the left ventricle (LV) segmentation which gives rise to a challenging multi-region seperation with the geometrical constraint (see the picture below, three regions: background, epicardium boundary (red) and endocardium (yellow)). For each region, we consider the global Bhattacharyya metric prior to evaluate a gray-scale and a radial distance (the shape prior) distribution matching. In this regard, the studied problem amounts to finding three regions that most closely match their respective input distribution model. It was previously addressed by curve evolution, which leads to sub-optimal and computationally intensive algorithms, or by graph cuts, which result in heavy metrication errors (grid bias). The proposed convex relaxation approach solves the LV segmentation through a sequence of convex sub-problems. Each sub-problem leads to a novel bound of the Bhattacharyya measure and yields the convex formulation which paves the way to build up the efficient and reliable solver.

In this respect, we propose a novel flow configuration that accounts for labeling function variations, in comparison to the existing flow-maximization configurations. We show it leads to a new convex max-flow formulation which is dual to the obtained convex relaxed sub-problem and does give the exact and global optimums to the original non-convex sub-problem. In addition, we present such flow perspective gives a new and simple way to encode the geometrical constraint of optimal regions. A comprehensive experimental evaluation on sufficient patient subjects demonstrates that our approach yields improvements in optimality and accuracy over related recent methods.

Related works:

• • M. S. Nambakhsh, Jing Yuan, Ismail Ben Ayed, K. Punithakumar, S. Li, A Convex Max-Flow Segmentation of the Left Ventricle using Subject-Specific Distributions, IEEE Trans. Medical Imaging (TMI) (in Preparation)

  • M. S. Nambakhsh, Jing Yuan, Ismail Ben Ayed, K. Punithakumar, S. Li, A Convex Max-Flow Segmentation of the Left Ventricle using Subject-Specific Distributions, Information Processing in Medical Imaging (IPMI) 2011