准静态弹性成像技术检测聚焦超声致离体组织损伤

目的 用准静态弹性成像检测聚焦超声(FUS)在离体组织中形成的损伤。方法 在仿体实验中采取多种方法提高运动估计的精度。通过分段线性拟合等算法对位移数据进行后处理,优化位移估计结果,采用基于小波变换的数字低通差分算法抑制应变估计中高频噪声的干扰。在此基础上用准静态弹性成像检测FUS在离体猪肌肉组织中形成的损伤。结果 采用分段线性拟合算法和基于小波变换的数字低通差分算法可显著改善运动估计的准确性。弹性成像可检测小剂量FUS辐照后在组织内形成的损伤,主要表现为损伤区域的力学特性与周围组织具有明显差异。结论 弹性成像可用于评价FUS形成的组织损伤。

Quasi-static elastography in monitoring in vitro tissue injuries induced by focused ultrasound

Objective To monitor injuries of in vitro tissue induced by focused ultrasound (FUS) irradiation with quasi-static elastography. Methods Several methods were used to improve the motion detection accuracy of elastography in phantom experiments. Algorithms such as piecewise linear approximation were applied to optimize the displacement data. Low pass digital difference algorithm based on wavelet transform was used to eliminate high frequency noise in displacement data during strain estimation. Experimental results on FUS induced injuries in pig muscle were introduced based on the phantom experiments. Results The accuracy of motion detection was significantly enhanced by using algorithms such as piecewise linear approximation and low pass digital difference algorithm based on wavelet transform. Injuries induced by small dosage of FUS in the tissue were successfully detected with elastography, which showed a major difference in the mechanical properties from the neighboring normal tissue. Conclusion Quasi-static elastography can evaluate the injuries induced by FUS in vitro.