Table of Contents
Journal of Medical Engineering
Volume 2014, Article ID 976323, 9 pages
Research Article

Image Segmentation and Analysis of Flexion-Extension Radiographs of Cervical Spines

1Department of Aerospace and Mechanical Engineering, University of Arizona, 1130 N. Mountain Avenue, Tucson, AZ 85721-0119, USA
2Department of Surgery, University of Arizona, 1501 N. Campbell Avenue, Tucson, AZ 85724-5070, USA

Received 2 June 2014; Revised 21 September 2014; Accepted 26 September 2014; Published 13 October 2014

Academic Editor: Ying Zhuge

Copyright © 2014 Eniko T. Enikov and Rein Anton. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We present a new analysis tool for cervical flexion-extension radiographs based on machine vision and computerized image processing. The method is based on semiautomatic image segmentation leading to detection of common landmarks such as the spinolaminar (SL) line or contour lines of the implanted anterior cervical plates. The technique allows for visualization of the local curvature of these landmarks during flexion-extension experiments. In addition to changes in the curvature of the SL line, it has been found that the cervical plates also deform during flexion-extension examination. While extension radiographs reveal larger curvature changes in the SL line, flexion radiographs on the other hand tend to generate larger curvature changes in the implanted cervical plates. Furthermore, while some lordosis is always present in the cervical plates by design, it actually decreases during extension and increases during flexion. Possible causes of this unexpected finding are also discussed. The described analysis may lead to a more precise interpretation of flexion-extension radiographs, allowing diagnosis of spinal instability and/or pseudoarthrosis in already seemingly fused spines.