title: Four-dimensional computed tomographic imaging in the wrist: proof of feasibility in a cadaveric model.
abstract: OBJECTIVE
  High-resolution real-time three-dimensional (3D) imaging of the moving wrist may provide novel insights into the pathophysiology of joint instability. The purpose of this work was to assess the feasibility of using retrospectively gated spiral computed tomography (CT) to perform four-dimensional (4D) imaging of the moving wrist joint.
  
  
  METHODS
  A cadaver forearm from below the elbow was mounted on a motion simulator which performed radioulnar deviation of the wrist at 30 cycles per minute. An electronic trigger from the simulator provided the "electrocardiogram" (ECG) signal required for gated reconstructions. Four-dimensional and 3D images were compared by a blinded observer for image quality and presence of artifacts.
  
  
  RESULTS
  Image quality of 4D images was found to be excellent at the extremes of radial and ulnar deviation (end-motion phases). Some artifacts were seen in mid-motion phases.
  
  
  CONCLUSIONS
  4D CT musculoskeletal imaging is feasible. Four-dimensional CT may allow clinicians to assess functional (dynamic) instabilities of the wrist joint.
authors.affiliation: Orthopedics Biomechanics Laboratory, Mayo Clinic College of Medicine, Rochester, MN, USA.
authors.forename: Shian-Chao
authors.initials: SC
authors.lastname: Tay
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Primak
authors.forename: Joel G
authors.initials: JG
authors.lastname: Fletcher
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schmidt
authors.forename: Kimberly K
authors.initials: KK
authors.lastname: Amrami
authors.forename: Richard A
authors.initials: RA
authors.lastname: Berger
authors.forename: Cynthia H
authors.initials: CH
authors.lastname: McCollough
mesh_terms: D016477:Artifacts; D002102:Cadaver; D005240:Feasibility Studies; D006801:Humans; D021621:Imaging, Three-Dimensional; D009068:Movement; D011857:Radiographic Image Interpretation, Computer-Assisted; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014955:Wrist Joint / Q000000981:diagnostic imaging*