非刚体配准在肝癌手术中的应用

Application of nonrigid registration in liver cancer treatment

提出了一种在由MR图像引导的肝癌手术中对癌症肿块定位的方法。该方法采用非刚体配准技术,将手术前获得的含有清晰肝癌肿块的CT图像与手术中实时获得的MR图像配准,从而确定MR图像中的癌症肿块的位置。该方法分为三个步骤:将CT和MR图像中的肝脏部位分割出来;对分割后的图像采用仿射变换进行粗配准;采用自由形变模型对图像进行精确配准。配准后肝脏表面的距离误差在1.5mm之内;通过视觉检查,其结果令人十分满意。

A semiautomatic nonrigid registration is proposed to match preoperative CT images and real-time MR images during the ablation of liver tumors.The method includes three parts.Firstly,the livers are extracted from CT and MR images.Since the CT image is acquired a several days before surgery,there is enough time for surgeons to segment the liver from the CT image manually.During the surgery,active contour is used to extract the liver from the MR image.Then,affine registration to match the images roughly.Finally,high accuracy registration is reached by free-form deformation registration.The results are evaluated by visual inspection and the distance of two liver surfaces.The error of liver surfaces is within 1.5 mm and the result of visual inspection is very well.