CT virtual endoscopy: preliminary clinical applications
Li Ziping, Xu Dasheng, Meng Quanfei. Department of Radiology, the First Affiliated Hospital, Sun Yatsen University of Medical Sciences, Guangzhou 510080
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.