Visceral fat inspection method based on the ultrasound tomographic reconstruction of abdominal tissue sound speed image

本文通过对人体腹部超声飞行时间数据的观测，对声学层析成像内脏脂肪检测仪的实现进行了研究和验证实验。特别是，研制了一套机械扫描系统，该系统采用了一对面向低频的高灵敏度宽带压电换能器，可以检测到通过远距离肠道气体介质传播的波，而不会受到声衰减。此外，在换能器的前面贴上了氨基甲酸酯凝胶半球体，以保持换能器与体表之间的良好接触，而不考虑它们之间的接触角。安装在自动执行机构平台上的用于旋转(直径720 mm)、平移(600 mm行程)和推进(300 mm行程)的面对对换能器由计算机控制以移动到腹部体表上的任意位置。在这个场合，…此外，为了最大限度地减少由于避免声音传播路径与脊椎相交而造成的数据丢失，确定了传播路径，以便将扫描旋转的中心调整到脊椎。为此，利用激光距离传感器测量了人体表面的轮廓，并预先估计了脊柱位置。通过这种方法，根据患者的体型和坐姿自适应地确定路径。此外，还监测了声波的幅度，以便可以将接触条件控制在最佳推送位置，而不考虑预先测量的身体表面位置的偏差。最后，利用体模试件进行的评价实验表明，飞行时间数据的测量精度足以再现腹部声速横断面图像。此外，从结果中证实了所提出的内脏脂肪测量技术的有效性，结果表明，可以以高精度将脂肪区域与剩余的蛋白质区域清晰地区分开来。虽然对人类患者的评价实验还有待进一步的工作，但该系统已经完成，该系统可以自动采集体表周围的声波数据，并从腹部重建的声速图像中测量内脏脂肪面积。较少

In the present study, investigations and validation experiments were made for the realization of acoustic tomographic visceral fat inspection apparatus based on the observation of ultrasound time of flight data around human abdominal surface. In particular, mechanical scanning system using a facing pair of high sensitivity broad band piezoelectric transducers in low frequency range was developed, so that waves propagated through the long distant intestinal gaseous medium can be detected without suffering sound attenuation. In addition, urethane gel hemi-spheres were attached in front of the transducers to keep good contact between transducer and body surface, regardless of contact angles between them. The facing pair transducers attached on the automated actuator stages for the movement of rotation (720 mm in diameter), translation (600 mm stroke), and pushing (300 mm stroke) were controlled by the computers to move to arbitral positions on the abdominal body surface. On this occasion, … More to minimize the loss of data caused by the avoidance of sound propagation paths intersecting a spine, propagation path was determined so that center of scanning rotation was adjusted to the spine. To this end, contour of the body surface was measured by laser range sensor and spine position was estimated in advance. By this means, the paths were adaptively determined in accordance with patient’s body size and sitting position. In addition, amplitudes of the sound waves were monitored so that contact condition can be controlled at an optimalpushing position regardless of the deviation of the premeasured body surface position. Finally, from the evaluation experiments by using the phantom specimen, it was shown that the measured precision of time of flight data were good enough to reproduce the abdominal sound speed cross sectional profile image. In addition, validity of the proposed visceral fat measurement techniques was confirmed from the results that fat areas can be clearly discriminated from the remaining protein areas with high degree of accuracy. Although the evaluation experiments for human patients were remained as future work, the system was brought to completion which can automatically collect the sound wave data around body surface andmeasure the visceral fat area from the abdominal reconstructed sound speed image. Less