Left Ventricle Segmentation in Cardiac Magnetic Resonance Imaging (MRI) by Modified Active Contour Method

The desired segmentation of medical images is a pivotal problem in medical image processing. Segmenting the Left Ventricle (LV) in Magnetic Resonance Images (MRIs) is essential for evaluation of cardiac function. For the segmentation of cardiac MRI several methods have been proposed and implemented. The aim of this paper was to use the segmentation of LV chamber with more accuracy and comparing the results with current methods. A modified region-based active contour model was applied. A new semi-automatic algorithm suggested calculating the appropriate Balloon force according to mean intensity of the region of interest for each image. The database is included of 2،039 MR images collected from 18 children under 18. The results were compared with previous literatures according to two standards: Dice Metric (DM) and Point to Curve (P2C) to get error values. According to defined standards، the obtained segmentation results are better than previously reported values in several literatures. In this study different points were used in cardiac cycle and several slices levels and classified into three levels: Base، Mid. and Apex. The better results were obtained at End Diastole (ED) in comparison with End Systole (ES)، and on base slice than other slices، because of LV bigger size in ED phase and base slice. With segmentation of LV MRI based on novel active contour and application of the suggested algorithm for balloon force calculation، the mean improvement of DM is 19. 6% in ED and 49. 5% in ES phase. Also the mean improvement of P2C for ED and ES phase is 43. 8% and 39. 6% respectively.