Diffraction-enhanced imaging of musculoskeletal tissues using a conventional x-ray tube

In conventional projection radiography, cartilage and other soft tissues do not produce enough radiographic contrast to be distinguishable from each other. Diffraction-enhanced imaging (DEI) uses a monochromatic x-ray beam and a silicon crystal analyzer to produce images in which attenuation contrast is greatly enhanced and x-ray refraction at tissue boundaries can be detected. The aim of this study was to test the efficacy of conventional x-ray tube-based DEI for the detection of soft tissues in experimental samples.

Cadaveric human tali (normal and degenerated) and a knee and thumb were imaged with DEI using a conventional x-ray tube and DEI setup that included a double-silicon crystal monochromator and a silicon crystal analyzer positioned between the imaged object and the detector.

Diffraction-enhanced images of the cadaveric tali allowed the visualization of cartilage and its specific level of degeneration for each specimen. There was a significant correlation between the grade of cartilage integrity as assessed on the tube diffraction-enhanced images and on their respective histologic sections (r = 0.97, P = .01). Images of the intact knee showed the articular cartilage edge of the femoral condyle, even when superimposed by the tibia. In the thumb image, it was possible to visualize articular cartilage, tendons, and other soft tissues.

DEI based on a conventional x-ray tube allows the visualization of skeletal and soft tissues simultaneously. Although more in-depth testing and optimization of the DEI setup must be carried out, these data demonstrate a proof of principle for further development of the technology for future clinical imaging.