CT仿真内窥镜成像技术临床应用的初步探讨

CT virtual endoscopy: preliminary clinical applications

目的探讨ＣＴ仿真内窥镜成像技术的原理、方法及临床应用价值。材料与方法将螺旋ＣＴ容积扫描数据传输到工作站。通过软件功能调整ＣＴ值阈值和透明度，显示含气器官或主动脉的内腔，赋予人工伪彩色，重建出沿空腔器官中轴行程一致的多幅器官内表面图像。再用电影功能依次回放，获得仿真内窥镜效果。用此方法检查２１例患者及正常人，其中喉部８例，气管支气管３例，结肠５例，主动脉５例。全部病例均经纤维内窥镜或手术病理证实。结果喉、气管支气管及结肠ＣＴ仿真内窥镜获得类似纤维内窥镜显示管腔器官腔壁或腔内病变形态的效果。尚能从梗阻远端观察病变情况。主动脉ＣＴ仿真内窥镜能显示血管内壁、假性动脉瘤的破口、夹层动脉瘤的内膜瓣。结论ＣＴ仿真内窥镜提供了一种无创伤性的诊断方法，可作为纤维内窥镜的补充手段，但其敏感性及特异性有待今后进一步研究提高。

Purpose To investigate the technical principles, method, and clinical applications of helical CT virtual endoscopy (CT VE).Materials and methods The volumetric data were acquired using a helical CT scanner and transferred to a computer workstation. The ranges of CT densities and transparency of gas containing organs or aorta were adjusted using customized computer software to show the inner walls of these organses. Colors were assigned to the inner walls to simulate the normal tissue color in vivo. To reproduce the simulated endoscopic view, multiple projection images were reconstructed along the longitudinal path of the tissues and played back in movie format. CT VE of the larynx (8), tracheobronchial tree (3), colon (5), and aorta (5) was performed on 6 normal volunteers and 15 patients with pathological confirmation by surgery or fiberoptic endoscopic biopsy. Results The appearances of the normal inner wall and lesions on CT VE of the larynx, tracheobronchial tree, and colon were similar to those of fiberoptic endoscopy. Additionally, lesions distal to obstruction could also be evaluated by CT VE. The inner wall of aorta, leaking pseudoaneurysm and intimal flap of dissecting aneurysm were also demonstrated by CT VE of the aorta. Conclusion CT VE provides an noninvasive diagnostic method to supplement fiberoptic endoscopy. However, the sensitivity and specificity of CT VE for lesion detection will require further improvement.