Characterising neovascularisation in fracture healing with laser Doppler and micro-CT scanning

Abstract

Vascularity of the soft tissues around a bone fracture is critical for successful healing, particularly when the vessels in the medullary canal are ruptured. The objective of this work was to use laser Doppler and micro-computer tomography (micro-CT) scanning to characterise neovascularisation of the soft tissues surrounding the fracture during healing. Thirty-two Sprague–Dawley rats underwent mid-shaft osteotomy of the left femur, stabilised with a custom-designed external fixator. Five animals were killed at each of 2, 4 days, 1, 2, 4 and 6 weeks post-operatively. Femoral blood perfusion in the fractured and intact contralateral limbs was measured using laser Doppler scanning pre- and post-operatively and throughout the healing period. At sacrifice, the common iliac artery was cannulated and infused with silicone contrast agent. Micro-CT scans of the femur and adjacent soft tissues revealed vessel characteristics and distribution in relation to the fracture zone. Blood perfusion dropped immediately after surgery and then recovered to greater than the pre-operative level by proliferation of small vessels around the fracture zone. Multi-modal imaging allowed both longitudinal functional and detailed structural analysis of the neovascularisation process.

Angiogenesis Assays for the Evaluation of Angiogenic Properties of Orthopaedic Biomaterials – A General Review

“…This technique is favorable for detecting blood flow of superficial layers of tissue with the maximum measurable depth for bone found to be around 3 mm . LDF is extensively used in research and clinical setting for measuring the microvascular bone perfusion of both cranial bone defects and long bones . MRI, particularly dynamic contrast‐enhanced MRI, is more often used to image the macrovascular blood flow of bone in the clinical setting with the use of gadolinium‐based contrast agent .…”

Effect of fixation on neovascularization during bone healing

“…The combination of micro-CT imaging and immuno-histochemical method may be more effective, since the latter method could identify regions of angiogenesis [35]. In addition, laser Doppler scanning, could be used to provide twodimensional (2D) surveys of the blood perfusion [36].…”

Characterization of the Developing Lacunocanalicular Network During Fracture Repair

“…µCT can increase in power when combined with other scanning and analysis modalities. For example, prior studies have attempted to combine µCT with laser Doppler to characterize neovascularization in healing fractures (33) . Our results present comprehensive snap-shots of LCN development in a quantitative fashion and were enabled by histological analysis combined with deconvolution microscopy/µCT.…”