How to measure scapholunate and Cobb's angles on MRI and CT

Abstract

The measurement of angles between anatomical structures is common in radiological and orthopedic practice. Frequently used measurements include scapholunate angle for assessment of wrist instability and Cobb's angle used for assessment of scoliosis. Measurements of these angles are easily performed on plain X-ray radiographs. However, the situation ismore complicated when thesemeasurements are to be performed on cross-sectional (CT or MRI) examinations. On some of the diagnostic workstations, it is not possible to performangle measurements between the structures if they are not identified on the same image and are located on different images of the same projection or plane. We present a simple solution to measure angles between structures on different images that can be used both in CT and MR. © 2011 Society for Imaging Informatics in Medicine.