超声导波定量评价长骨骨折状况

采用超声导波评价长骨骨折已成为近年来的研究热点之一,为了定量地评价长骨骨折状况,本文采用二维时域有限差分仿真方法定量分析了超声导波在部分断裂和完全断裂的长骨中的传播情况.结果表明,采用低频窄带高斯包络正弦信号可成功激励出两个低阶导波模式S0和A0,其中A0模式对长骨骨折状况较为敏感.S0和A0模式幅度的比值S0/A0被用于评价长骨骨折程度,S0/A0随裂纹宽度、裂纹深度的增加显著上升.因此超声导波模式转换现象可用于定量表征骨折长骨的裂纹深度和裂纹宽度的变化,对长骨骨折愈合的监测也具有一定意义.

Quantitative evaluation of long bone fractures by ultrasonic guided waves

Using ultrasonic guided waves to assess fractured long bone has become one of the hottest topics in recent years. To quantitatively evaluate long bone fractures, this paper uses two-dimension finite-difference time-domain （FDTD） simulations to quantitatively analyze the transmission of guided wave in long bone with partially and completely diaphyseal osteotomy. It is illustrated that under the narrowband low-frequency excitation, two fundamental guided modes S0 and A0 can be excited successfully. Different from S0 mode, A0 mode is very sensitive to the fracture geometry. An amplitude ratio parameter between SO and A0 （S0/A0） is proposed to quantify the bone fracture degree. The simulation indicates that S0/A0 significantly increases with the fracture deepening and widening. Thus, the guided mode conversion can be used to evaluate depth and width of the diaphyseal fracture, which may also be helpful to monitor the fracture healing of long cortical bone.