Automatic motion analysis of bones from MR sequences

In many cases articular damages cannot be diagnosed through an examination of a single image. A motion analysis of a joint´s bones might be necessary to make a reliable diagnosis. Examples are lesions of the ligaments and cartilage of the knee or in the cervical and lumbar regions of the vertebral. This paper presents a novel system to diagnose lesions of the ligaments of the wrist (carpal instabilities). The method is particularly well-suited to aid in the diagnosis of the scapho-lunate instability. This damage is a common injury after accidents involving the wrist. The lesion occurs when the ligaments between the scaphoid and the lunate are torn. Motion graphs show the rotation as well as the translation of the carpal bones. The measurement is performed relative to an anatomic co-ordinate system defined by the distal end of the radius. Compared to other applications a motion analysis of the wrist bones is more difficult because there are many bones with a similar shape which complicates their identification. Furthermore some of the bones may tilt, that is they may rotate around axes not perpendicular to the view plane. This results in a varying appearance of the bones in the sliced magnetic resonance (MR) images