Characterization of 3D joint space morphology using an electrostatic model (with application to osteoarthritis)

Qian Cao, Gaurav Thawait, Grace J. Gang, Wojciech Zbijewski, Thomas Reigel, Tyler Brown, Brian Corner, Shadpour Demehri, Jeffrey H. Siewerdsen

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Joint space morphology can be indicative of the risk, presence, progression, and/or treatment response of disease or trauma. We describe a novel methodology of characterizing joint space morphology in high-resolution 3D images (e.g. cone-beam CT (CBCT)) using a model based on elementary electrostatics that overcomes a variety of basic limitations of existing 2D and 3D methods. The method models each surface of a joint as a conductor at fixed electrostatic potential and characterizes the intra-articular space in terms of the electric field lines resulting from the solution of Gauss' Law and the Laplace equation. As a test case, the method was applied to discrimination of healthy and osteoarthritic subjects (N = 39) in 3D images of the knee acquired on an extremity CBCT system. The method demonstrated improved diagnostic performance (area under the receiver operating characteristic curve, AUC > 0.98) compared to simpler methods of quantitative measurement and qualitative image-based assessment by three expert musculoskeletal radiologists (AUC = 0.87, p-value = 0.007). The method is applicable to simple (e.g. the knee or elbow) or multi-axial joints (e.g. the wrist or ankle) and may provide a useful means of quantitatively assessing a variety of joint pathologies.

Original languageEnglish (US)
Pages (from-to)947-960
Number of pages14
JournalPhysics in medicine and biology
Issue number3
StatePublished - Feb 7 2015


  • arthritis
  • bone
  • computed tomography
  • electrostatics
  • joint space
  • knee
  • modeling

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging


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