Background/Purpose:

This project developed a new method for evaluating growing joints by employing diffraction enhanced imaging (DEI) with computed tomography (CT) using a synchrotron light source.  DEI is a technique that, compared to conventional radiography, generates more detailed images with a lower radiation dose. DEI develops contrast both from absorption, the process involved in conventional radiography, and from x-ray refraction and diffraction reduction.  We show that three-dimensional CT in combination with DEI yields more detailed images than DEI alone or than any other currently available conventional imaging modality.  This project, the first to use DEI-CT for imaging intact growing joints, introduces a new tool for studying inflammatory joint diseases during growth.

Methods:

Explanted piglet stifle joints, which are anatomically similar to human knees, were imaged.  Joints were from healthy 4-week old piglets which have skeletal maturation equivalent to a 10 month old child. Images were acquired at the Canadian Light Source synchrotron.  The DEI-CT scanned slices were “stitched” together forming a three-dimensional (3D) dataset. To compare DEI-CT with other imaging modalities we imaged the stifle joint using planar DEI (with no CT) and conventional radiography, CT and MRI. To begin to explore pathology we imaged joints that were iatrogenically damaged with 200 µm diameter acupuncture needles. Bone and cartilage histology was correlated with DEI-CT features. 

Results:

DEI-CT demonstrated bone and soft tissue detail within all joint tissues. Cartilage edges, cartilage-bone interfaces, cortical shell, trabecular bone, and ligaments were clearly displayed.  Vascular canals within cartilage and traversing between bone and cartilage, characteristics of growing but not mature joints, were clearly visualized. Resolution of DEI-CT was more detailed than with other imaging modalities. The 200 µm traumatic sites were clearly discerned. Histological assessment confirmed the presence of vascularity in articular cartilage. 

Conclusion:

This report documents DEI combined with CT and using synchrotron light yields more detailed 3D images of growing joints than conventional imaging modalities.  Using DEI-CT in a large animal model during growth affords opportunities to better characterize both normal and pathologic growth.  Studying inflammatory joint diseases in the piglet provides a valuable animal model to study pathology and treatment responses in juvenile arthritis.  These results provide a basis and impetus for developing clinically accessible, non-synchrotron based DEI-CT technologies.

« Back to 2015 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/imaging-growing-joints-by-diffraction-enhanced-computed-tomography-using-a-synchrotron-light-source/