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

本研究的结果包括三个部分。1)体外标记用于超声内窥镜的三维定位器。2)腔内超声重建三维超声图像：幻影研究。3)腔内超声重建三维超声图像：临床研究及与其他成像方式的比较。1)我们提出了一种可以识别插入人体内部的超声扫描探头的三维位置和方向，并给出内窥镜图像的方法。利用放置在人体表面的标记换能器，将同步脉冲传递给超声扫描仪，描述了利用自适应阈值和鲁棒算法在超声内窥镜扫描图像上测量标记位置（体内扫描探头与体外换能器之间的方向和距离）的方法。我们采用了一大块表面有海湾的火腿作为胆管幻影。采用回拉装置，将腔内超声探头放置于蜂房裂口附近，在长轴方向上每幅图像拉伸0.1mm，获得连续的短轴超声图像。以短轴超声图像为基础，采用表面绘制方法获得长轴重建图像和三维图像。我们可以获得任何方向的超声图像和幻影表面的三维图像。3)我们采用与两例临床病例的假体图像相同的方法获得了重建图像和表面绘制法获得的三维图像。将重建图像与3D图像、CT与MRI图像进行对比，重建图像和3D图像对胆管肿瘤及其淋巴结转移的显示均不及CT和MRI。考虑的问题是超声图像对比度分辨率低、腔内超声探头在胆总管内扭曲、腔内超声探头穿透距离短。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