Evaluation on Spatial extension and lymph node metastasis of Biliary tract tumors with Three-dimentional ultrasound image

本研究的成果由三部分组成。1)利用体外标记物实现超声内窥镜三维定位。2)腔内超声重建三维超声图像：体模研究。3)腔内超声重建三维超声图像：临床研究及与其他成像模式的比较1)提出了一种识别超声扫描探头插入体内的三维位置和方向的方法，从而获得内窥镜图像。利用放置在体表上的标记物换能器，使探头脉冲与超声扫描仪同步，采用自适应阈值和稳健算法对超声内窥镜扫描图像上标记物的位置(体内外扫描探头与体外换能器之间的方向和距离)进行测量。2)将一块有缝隙的火腿作为胆管模型。获得了连续短轴超声…通过将腔内超声探头放置在靠近嗡嗡声间隙的位置，使用回拉装置在长轴方向上每幅图像绘制0.1 mm的图像，以获得更多的3D图像。在短轴超声图像的基础上，采用表面绘制的方法获得了长轴重建图像和三维图像。可以获得体模在任意方向的超声图像和体模表面的三维图像。3)用同样的方法获得重建图像和体模表面的三维图像，并在两个临床病例中获得体模图像。将重建图像与3D图像、CT与MRI进行比较，在显示胆管肿瘤及其淋巴结转移方面，重建及3D图像均不如CT和MRI。所考虑的问题是超声图像的低对比度，腔内超声探头在胆总管内扭曲，腔内超声探头穿透距离短。较少

The result of this research consists of three parts. 1) 3D localizer for ultrasound endoscope by outside-body markers. 2) Reconstruction of 3D ultrasound images using intraluminal ultrasound : phantom study. 3) Reconstruction of 3D ultrasound images using intraluminal ultrasound : clinical study and comparison with other imaging modalities.1) We proposed a method with which we can identify 3D position and direction of ultrasound scanning probe inserted into inside of the body, which gives endocopic image. We use marker transducers placed on surface of the body, which tansit pulses synchronized to ultrasound scanner, The method of measuring position(direction and distance between scanning probe inside of the body and transducer outside of the body) of marker on the scanned image obtained with ultrasound endoscope by using adaptive threshold and robust algorithm is described.2) We adapted a mass of ham surfaced with gulf as a bile duct phantom. We obtained continuous short-axis ultrasoun … More d image by placing the intraluminal ulrasound probe near the gulf of the hum drawing 0.1mm per image in the long-axis direction using pull-back device. We obtained long-axis reconstructed images and 3D images with surface rendering method based on the short-axis ultrasound image. We could obtain the ultrasound images of the phantom in any direction and 3D images od the surface of the phantom.3) We obtained the reconstruction images and 3D images obtained with surface rendering method with the same method we obtained the phantom images in two clinical cases. Comparison was made between the reconstruction and 3D images, and CT and MRI, In both cases, the reconstruction and 3D images were inferior to CT and MRI in the demonstration of bile duct tumor and its lymph node metastasis. The problems considered were inherit lowcontrast resolution of ultrsound images, twisting of the intraluminal ultrasound probe in the common bile duct, and short penetration distance of the intraluminal ultrasound probe. Less