Semi-automatic segmentation using MR images II

• Main Author: Lung, Wen Zheng.
• Other Authors: Poh Chueh Loo
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Bioengineering
• Online Access: http://hdl.handle.net/10356/16492
• Institution: Nanyang Technological University

The objective of this project is to develop a method to automatically segment the Articular Cartilage Ligament (ACL) of the knee in Magnetic Resonance (MR) images. Even though MR imaging technology provides a non-invasive and accurate diagnosis of ACL injury, the images require interpretation by trained radiologists. And because the ACL is the most frequently injured structure in the knee, an automated segmentation method is needed to aid radiologists in handling the large volumes of MR images. The ACL is positioned amongst many other ligamentous structures of the knee; it therefore does not have good contrast with its surrounding tissue in MR images, which makes it difficult for computers to automatically identify it – an algorithm which can achieve unsupervised segmentation of the ACL has not been documented to date. The algorithm developed in this project is implemented using MATLAB, and uses mathematical morphology to locate the ACL without supervision, allowing the algorithm to take advantage of the ACL’s unique shape and orientation within the image. A series of morphological filters are applied to the image, thereafter an active contour model is employed to delineate the boundary of the ACL. The semi-automatically segmented images were compared against a set of manually segmented images to determine the accuracy of the segmentation. The present algorithm is able to correctly identify the ACL in 92.5% of the images, and a dice coefficient of 80.5% (compared against the manually segmented images) is achieved in MR images where the ACL is physiologically healthy.