基于64层螺旋CT断层图像的影像后处理-大肠三维重建及虚拟内镜

Image post-processing based on 64-slice helical CT sectional images: three-dimensional reconstruction and virtual endoscopy of large intestine

目的:寻求基于64层螺旋CT断层图像在个人电脑重建大肠三维数字模型及虚拟内镜检查的方法.方法:Philips/Brilliance64对胸9至股骨中段沿横断面平扫及动脉期和静脉期连续跟踪扫描.基于空气灌肠造影平扫CT数据,使用VGL3.2共享软件包用Ray-Casting光线投射算法对肠管进行体绘制,Mimics软件用MC(marching cubes)算法对肠管进行面绘制及用虚拟内镜法(VE)重建三维图像.Mimics软件基于CTA二维图像对大肠及周围结构等各种组织进行三维重建.结果:成功建立了较精确的大肠体绘制和面绘制模型及大肠及周围结构三维数字模型,包括骨骼系统,动脉系统,泌尿系,皮肤,大肠及部分小肠.实现了三维交互式浏览和虚拟内镜的应用.结论:大肠可视化模型准确反映其复杂的解剖结构及空间毗邻关系,不但为临床诊断提供可靠的解剖资料,也为今后的虚拟手术打下了良好的基础.

AIM： To find a method to reconstruct a large intestine three-dimensional digital model and virtual endoscopic examination based on 64-slice helical CT image in personal computer. METHODS： We used Philips/Brilliance 64 CT to complete plain scan from the 9th thoracic vertebra to middle-femur and continuously tracked scan of arterial phase and venous phase. Based on the CT plain scan after air pressure enema, we used the VGL 3.2 sharewares to carry on the volume rendering of intestine with the Ray-Cast- ing light projection algorithm. Mimics software for the surface was used to render intestines with the Marching Cubes algorithm then three dimensional graphics were reconstructed using virtual endoscopy （VE）. We reconstructed three- dimensional large intestine and surrounding structures with the Mimics software separately based on the CTA two-dimensional graphics. RESULTS： We have established a more precise model of volume rendering and surface rendering of large intestine and surrounding structures, including skeletal system, arterial system, urinary tract, skin, large intestine and part of small intestine. We have achieved a threedimensional interactive browsing and virtual endoscopic applications. CONCLUSION： The large intestine visualization model could show precisely complex anatomical structure and spatial adjoining relations, which not only offers clinic doctors reliable anatomical information, but also a good base for later vir- tual surgery.