Imaging of cortical pores using ultrasound contrast agents: Phantom and ex vivo studies

We have investigated the feasibility of imaging cortical pores using ultrasound contrast agents (UCA). Cortical bone porosity and pore size are major factors in determining bone strength and toughness. Assessments on cortical pore properties can help to predict and prevent bone fractures. Because cortical pores are highly associated with blood vessels, imaging cortical bone microvascular perfusion can provide information on vascularized cortical pores. In previous research, the feasibility of imaging the microvascular perfusion through the skull bone in vivo has been demonstrated. In this study, we adopt the same methods, i.e., nonlinear UCA and temporal perfusion index (TPI), to image microvascular perfusion inside the cortical bone. The study has been conducted on a porous phantom and on a human femur shaft sample. Both phantom and ex vivo results have shown that the combination of UCA and TPI have the potential for imaging of vascularized cortical pores.