Temporal blood flow changes measured by diffuse correlation tomography predict murine femoral graft healing

Abstract

Blood flow changes during bone graft healing have the potential to provide important information about graft success, as the nutrients, oxygen, circulating cells and growth factors essential for integration are delivered by blood. However, longitudinal monitoring of blood flow changes during graft healing has been a challenge due to limitations in current techniques. To this end, non-invasive diffuse correlation tomography (DCT) was investigated to enable longitudinal monitoring of three-dimensional blood flow changes in deep tissue. Specific to this study, longitudinal blood flow changes were utilized to predict healing outcomes of common interventions for massive bone defects using a common mouse femoral defect model. Weekly blood flow changes were non-invasively measured using a diffuse correlation tomography system for 9 weeks in three types of grafts: autografts (N = 7), allografts (N = 6) and tissue-engineered allografts (N = 6). Healing outcomes were quantified using an established torsion testing method 9 weeks after transplantation. Analysis of the spatial and temporal blood flow reveals that major differences among the three groups were captured in weeks 1–5 after graft transplantation. A multivariate model to predict maximum torque by relative blood flow changes over 5 weeks after graft transplantation was built using partial least squares regression. The results reveal lower bone strength correlates with greater cumulative blood flow over an extended period of time (i.e., 1–5 weeks). The current research demonstrates that DCT-measured blood flow changes after graft transplantation can be utilized to predict long-term healing outcomes in a mouse femoral graft model.

High-density speckle contrast optical tomography of cerebral blood flow response to functional stimuli in the rodent brain

“…On the contrary, high-density data do not scale well in DCS/DCT because the monetary cost is prohibitively large since it requires expensive fast detectors for every added detector position. 18,19,23 Figure 8 shows the performance of SCOT for the imaging of CBF in detail. As it is very typical of neuroimaging methods, intertrial, intra-animal, and inter-animal averaging were utilized.…”

“…[15][16][17] This is not, so far, accessible for diffuse correlation tomography (DCT). [18][19][20] To date, DCT has been limited to pilot studies on small animals 18,19 and coarse measurements on humans. 20 Recently, speckle contrast optical spectroscopy/tomography (SCOS/SCOT) was introduced to overcome some of these limitations.…”

Longitudinal 3D Blood Flow Distribution Provided by Diffuse Correlation Tomography during Bone Healing in a Murine Fracture Model

“…In our laboratory, a noncontact DCT technique has been developed for assessing blood flow in a murine femoral graft model. The DCT technique has been verified and applied in previous tissue phantom and longitudinal bone graft monitoring studies . In our weekly bone graft measurements, blood flow in grafts increased at one week after graft surgery.…”

Wirelessly operated bioelectronic sutures for the monitoring of deep surgical wounds

“…Our results establish that the power, bandwidth, and sensitivity requirements for wireless operation are well within the specifications of commercially-available radio-frequency integrated circuits 45 , such that the system can be implemented as a compact, battery-powered wearable device. This device will enable surveillance of post-operative complications even outside of clinical settings, which has important medical implications for the detection of leakage from gastrointestinal anastomoses [46][47][48] or monitoring the patency of blood vessels in surgical grafts 49,50 . Further validation of the wireless functionality over time durations relevant to postoperative monitoring, as well as the long-term biocompatibility of the sutures, is needed to establish medicalgrade suture performance.…”