Level set based vertebra segmentation for the evaluation of <i>Ankylosing Spondylitis</i>

Sovira Tan; Jianhua Yao; Michael M. Ward M.D.; Lawrence Yao M.D.; Ronald M. Summers M.D.

doi:10.1117/12.652399

10 March 2006 Level set based vertebra segmentation for the evaluation of Ankylosing Spondylitis

Sovira Tan, Jianhua Yao, Michael M. Ward M.D., Lawrence Yao M.D., Ronald M. Summers M.D.

Proceedings Volume 6144, Medical Imaging 2006: Image Processing; 614407 (2006) https://doi.org/10.1117/12.652399
Event: Medical Imaging, 2006, San Diego, California, United States

Abstract

Ankylosing Spondylitis is a disease of the vertebra where abnormal bone structures (syndesmophytes) grow at intervertebral disk spaces. Because this growth is so slow as to be undetectable on plain radiographs taken over years, it is necessary to resort to computerized techniques to complement qualitative human judgment with precise quantitative measures on 3-D CT images. Very fine segmentation of the vertebral body is required to capture the small structures caused by the pathology. We propose a segmentation algorithm based on a cascade of three level set stages and requiring no training or prior knowledge. First, the noise inside the vertebral body that often blocks the proper evolution of level set surfaces is attenuated by a sigmoid function whose parameters are determined automatically. The 1st level set (geodesic active contour) is designed to roughly segment the interior of the vertebra despite often highly inhomogeneous and even discontinuous boundaries. The result is used as an initial contour for the 2nd level set (Laplacian level set) that closely captures the inner boundary of the cortical bone. The last level set (reversed Laplacian level set) segments the outer boundary of the cortical bone and also corrects small flaws of the previous stage. We carried out extensive tests on 30 vertebrae (5 from each of 6 patients). Two medical experts scored the results at intervertebral disk spaces focusing on end plates and syndesmophytes. Only two minor segmentation errors at vertebral end plates were reported and two syndesmophytes were considered slightly under-segmented.

Citation Download Citation

Sovira Tan, Jianhua Yao, Michael M. Ward M.D., Lawrence Yao M.D., and Ronald M. Summers M.D. "Level set based vertebra segmentation for the evaluation of Ankylosing Spondylitis", Proc. SPIE 6144, Medical Imaging 2006: Image Processing, 614407 (10 March 2006); https://doi.org/10.1117/12.652399

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available