Peripheral quantitative CT (pQCT) using a dedicated extremity cone-beam CT scanner

A. A. Muhit, S. Arora, M. Ogawa, Y. Ding, W. Zbijewski, J. W. Stayman, G. Thawait, N. Packard, R. Senn, D. Yang, J. Yorkston, C. O. Bingham, K. Means, J. A. Carrino, J. H. Siewerdsen

Research output: Chapter in Book/Report/Conference proceedingConference contribution

13 Scopus citations


Purpose: We describe the initial assessment of the peripheral quantitative CT (pQCT) imaging capabilities of a conebeam CT (CBCT) scanner dedicated to musculoskeletal extremity imaging. The aim is to accurately measure and quantify bone and joint morphology using information automatically acquired with each CBCT scan, thereby reducing the need for a separate pQCT exam. Methods: A prototype CBCT scanner providing isotropic, sub-millimeter spatial resolution and soft-tissue contrast resolution comparable or superior to standard multi-detector CT (MDCT) has been developed for extremity imaging, including the capability for weight-bearing exams and multi-mode (radiography, fluoroscopy, and volumetric) imaging. Assessment of pQCT performance included measurement of bone mineral density (BMD), morphometric parameters of subchondral bone architecture, and joint space analysis. Measurements employed phantoms, cadavers, and patients from an ongoing pilot study imaged with the CBCT prototype (at various acquisition, calibration, and reconstruction techniques) in comparison to MDCT (using pQCT protocols for analysis of BMD) and micro-CT (for analysis of subchondral morphometry). Results: The CBCT extremity scanner yielded BMD measurement within ±2-3% error in both phantom studies and cadaver extremity specimens. Subchondral bone architecture (bone volume fraction, trabecular thickness, degree of anisotropy, and structure model index) exhibited good correlation with gold standard micro-CT (error ~5%), surpassing the conventional limitations of spatial resolution in clinical MDCT scanners. Joint space analysis demonstrated the potential for sensitive 3D joint space mapping beyond that of qualitative radiographic scores in application to non-weight-bearing versus weight-bearing lower extremities and assessment of phalangeal joint space integrity in the upper extremities. Conclusion: The CBCT extremity scanner demonstrated promising initial results in accurate pQCT analysis from images acquired with each CBCT scan. Future studies will include improved x-ray scatter correction and image reconstruction techniques to further improve accuracy and to correlate pQCT metrics with known pathology.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2013
Subtitle of host publicationBiomedical Applications in Molecular, Structural, and Functional Imaging
StatePublished - 2013
EventMedical Imaging 2013: Biomedical Applications in Molecular, Structural, and Functional Imaging - Lake Buena Vista, FL, United States
Duration: Feb 10 2013Feb 13 2013

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


OtherMedical Imaging 2013: Biomedical Applications in Molecular, Structural, and Functional Imaging
Country/TerritoryUnited States
CityLake Buena Vista, FL


  • Bone mineral density
  • Bone morphometry
  • Cone-beam CT (CBCT)
  • Joint morphology
  • Joint space analysis
  • Osteoarthritis
  • Osteoporosis
  • Peripheral quantitative computed tomography (PQCT)
  • Rheumatoid arthritis

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging
  • Biomaterials


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