Feasibility investigation of logarithmic Nakagami parametric imaging in recovering underestimated perfusion metrics of DCEUS in the uneven acoustic field
Feasibility investigation of logarithmic Nakagami parametric imaging in recovering underestimated perfusion metrics of DCEUS in the uneven acoustic field
复制标题
对数 Nakagami 参数成像恢复不均匀声场中 DCEUS 低估灌注指标的可行性研究
DOI：
10.1002/mp.15527
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发表时间：
2022-02-18
期刊：
影响因子：
3.8
通讯作者：
Wan, Mingxi
中科院分区：
文献类型：
--
作者：
Wang, Diya;Ma, Quanlong;Wan, Mingxi
目的在聚焦脉冲发射的振幅编码动态超声造影（DCEUS）中，由于微泡后向散射回波的振幅受不均匀声场的影响，导致对血流动力学的错误估计。本研究的目的是调查的可行性和性能的Nakagami轮廓特征参数成像，以恢复上述错误估计。方法采用Nakagami对数参数（m）编码的DCEUS方案，在两种不同深度的非均匀声场中，对4只家兔进行模拟、离体MB模型和在体肾脏灌注实验。在体内组织伪影的m估计抑制脉冲反转二次谐波成像和增强其鲁棒性的多尺度矩估计策略。时间Nakagami-m曲线和相应的灌注指标的强度和体积计算的对数m-编码的DCEUS图像内的预聚焦和焦点区域。将这些曲线和指标进一步与相同区域内传统幅度编码图像估计的灌注曲线和指标进行比较。结果与非线性散射MB回波幅度相比，其对数m值与声压的变化相对无关。与固定尺度矩估计相比，对数m编码DCEUS方案采用多尺度统计矩估计的灌注强度在病灶前和病灶区之间的差异较小。由不均匀声场引起的灌注强度差异降低到3.47% +/-1.58%。对数m编码DCEUS方案降低的差异进一步由m估计的阈值调节。结论对数m编码DCEUS方案可以恢复被低估的MB后向散射回波和由不均匀声场引起的误估计灌注强度。该方案有可能削弱在不均匀声场中组织或肿瘤内标记的微血管识别和血流动力学表征的局限性。
Purpose Owing to acoustic-pressure dependence, amplitudes of backscattered-echoes of encapsulated microbubbles (MBs) are unavoidably regulated by an uneven acoustic field, resulting in the misestimation of hemodynamics in conventional amplitude-coding dynamic contrast-enhanced ultrasound (DCEUS) with focused pulse transmission. This study aimed to investigate the feasibility and performance of Nakagami statistical-feature parametric imaging to recover the above misestimation. Methods Logarithmic Nakagami parameter (m)-coding DCEUS scheme was investigated via simulation and in vitro MB phantoms as well as in vivo kidney-perfusion experiments of four rabbits in the uneven acoustic fields with two different focal depths. In vivo tissue artifacts for m estimation were suppressed by pulse-inversion second-harmonic imaging and its robustness was enhanced by multiscale moment-estimation strategy. Time-Nakagami-m curves and the corresponding perfusion metrics of intensity and volume were calculated from the logarithmic m-coding DCEUS images within the prefocal and focal regions. These curves and metrics were further compared with the perfusion curves and metrics estimated from the conventional amplitude-coding images within the same regions. Results Compared with amplitudes of nonlinear scattering MB echoes, their logarithmic m values were relatively independent of the changes in acoustics pressures. Compared with the fixed-scale moment-estimation, the perfusion intensity estimated from logarithmic m-coding DCEUS scheme using multiscale statistical moment-estimation had smaller differences between the prefocal and focal regions. The differences of perfusion intensity induced by an uneven acoustic field decreased to 3.47% +/- 1.58 %. The differences decreased by the logarithmic m-coding DCEUS scheme were further regulated by threshold values of m estimation. Conclusions The logarithmic m-coding DCEUS scheme could recover the underestimated MB backscattered-echoes and the misestimated perfusion intensity induced by the uneven acoustic field. The scheme had the potential to weaken the limitation of microvasculature identification and hemodynamic characterization marked by MBs within tissues or tumors in the uneven acoustic field.