Low-dose phase-based X-ray imaging techniques for in situ soft tissue engineering assessments

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Materials Science

Background:

• Non-invasive imaging is crucial for assessing biomaterial scaffolds and tissue repair in longitudinal animal studies.
• Conventional X-ray imaging lacks sufficient contrast for soft tissues and low-density biomaterials.
• X-ray phase-based imaging techniques offer enhanced contrast by utilizing refraction and phase effects.

Purpose of the Study:

• To explore and compare three synchrotron phase-based X-ray imaging techniques: computed tomography-diffraction enhanced imaging (CT-DEI), analyzer-based imaging (ABI), and phase contrast imaging (PCI).
• To evaluate these techniques for visualizing and characterizing low-density biomaterial scaffolds and soft tissues in situ within a live animal model.
• To assess strategies for reducing radiation dose and scan time for in vivo applications.

Main Methods:

• Comparison of CT-DEI, ABI, and PCI using polycaprolactone scaffolds implanted in intact pig joints.
• Qualitative and quantitative assessment of imaging performance.
• Evaluation of dose reduction strategies including reduced CT projections, region of interest selection, and low-resolution imaging.

Main Results:

• Phase-based X-ray imaging techniques demonstrated significant capabilities for in situ visualization of biomaterial scaffolds and soft tissues.
• Low-dose imaging strategies effectively reduced radiation exposure to levels suitable for live animal imaging.
• CT-DEI exhibited superior efficiency in maintaining image contrast at low radiation doses compared to ABI and PCI.

Conclusions:

• Synchrotron phase-based X-ray imaging techniques are promising for non-invasive assessment in soft tissue engineering.
• Effective low-dose imaging strategies enable longitudinal in vivo studies.
• CT-DEI is the most efficient phase-based technique for high-contrast imaging of biomaterials and soft tissues in live animals at reduced radiation doses.