Shuai Leng PhD, Presenter: Nothing to Disclose

Kristin D. Zhao MA, Abstract Co-Author: Research support, Socorex Isba SA

Sanjeev Kakar MD, Abstract Co-Author: Nothing to Disclose

Steven Moran MD, Abstract Co-Author: Nothing to Disclose

Kai-Nan An PhD, Abstract Co-Author: Nothing to Disclose

Cynthia H. McCollough PhD, Abstract Co-Author: Research grant, Siemens AG

Naveen Srinivasa Murthy MD, Abstract Co-Author: Nothing to Disclose

Richard Berger MD, Abstract Co-Author: Nothing to Disclose

To identify which motion is able to best visualize dynamic scapholunate joint instabilities using 4-dimensional (4D) CT.

Three patients with a clinical suspicion of unilateral dynamic scapholunate wrist ligament injury were scanned in a prone position in this IRB-approved study using a dual source 128-slice CT scanner (Definition Flash, Siemens Healthcare, Forchheim, Germany). A CT-compatible device was developed to support and constrain the subject’s forearm during wrist motion. A 4DCT technique was developed to acquire dynamic image data while patients moved their wrists in ways common to activities of daily living. Each wrist was scanned separately during three types of wrist motion: radial-ulnar deviation, flexion-extension, and dart thrower’s motion. Data were acquired for 2 seconds for each type of motion. A commercial dual source reconstruction algorithm was used to generate images with 75 ms temporal resolution, and 4D movies were generated from the time series volume rendered images (VRT). Two orthopedic hand surgeons reviewed side by side movies of both wrists for each motion and scored the difference between the normal and injured wrist using a 5 point ordinal scale (1=no difference to 5=obvious difference).

Using 4DCT imaging and VRT displays, dynamic kinematics of the carpal bones in relation to the distal radius and ulna were directly observed. Motion of the scaphoid and lunate and the joint space between them were clearly visualized throughout the wrist motion cycle. For all three patients, at least one motion was scored 4 or higher by both reviewers, indicating a substantial difference between the normal and injured wrists. The average scores from both readers over all 4 subjects were 4.0, 4.0 and 2.8 for radial-ulnar deviation, flexion extension, and dart thrower’s motion.

The 4DCT technique generated high spatial and high temporal resolution (75 ms) images of the moving wrist joint. Differences in carpal bone motion and joint spacing between the normal wrist and injured wrist were observed. Radial-ulnar deviation and flexion-extension motions were more sensitive to detecting a difference between the injured and uninjured wrist compared to the dart thrower’s motion.

4DCT imaging may provide clinicians a sensitive tool for detecting dynamic scapholunate injury. Early detection and treatment may prevent the development of wrist arthritis.

Leng, S, Zhao, K, Kakar, S, Moran, S, An, K, McCollough, C, Murthy, N, Berger, R, Assessment of Scapholunate Instability Using a 4D CT Imaging Technique for the Wrist.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11009212.html