Evaluation of Tracheobronchial Diseases: Comparison of Different Imaging Techniques Qihang Chen, MD1, 2 Jin Mo Goo, MD1 Joon Beom Seo, MD3 Myung Jin Chung, MD1 Yu-Jin Lee, MD1 Jung-Gi Im, MD1 Index words: Bronchi, CT Computed tomography (CT), three-dimensional Computed tomography (CT), volume rendering Korean J Radiol 2000;1:135-141 Received July 7, 2000; accepted after revision August 25, 2000. Department of 1Radiology, Seoul National University College of Medicine and the Institute of Radiation Medicine, SNUMRC; Department of 2Radiology, Beijing Hospital; Department of 3Radiology, Gil Medical Center, Gachon Medical School Supported in part by a research grant from BK21 Address reprint requests to: Jung-Gi Im, MD, Department of Radiology, Seoul National University Hospital, 28 Yongon-dong, Chongno-gu, Seoul 110- 744, Korea. Telephone: (822) 760-3338 Fax: (822) 743-6385 e-mail: imjg@radcom.snu.ac.kr Objective: To compare the clinical utility of the different imaging techniques used for the evaluation of tracheobronchial diseases. Materials and Methods: Forty-one patients with tracheobronchial diseases [tuberculosis (n = 18), bronchogenic carcinoma (n = 10), congenital abnormality (n = 3), post-operative stenosis (n = 2), and others (n = 8)] underwent chest radi- ography and spiral CT. Two sets of scan data were obtained: one from routine thick-section axial images and the other from thin-section axial images. Multiplanar reconstruction (MPR) and shaded surface display (SSD) images were obtained from thin-section data. Applying a 5-point scale, two observers compared chest radiography, routine CT, thin-section spiral CT, MPR and SSD imaging with regard to the detection, localization, extent, and characterization of a lesion, information on its relationship with adjacent structures, and overall infor- mation. Results: SSD images were the most informative with regard to the detection (3.95 0.31), localization (3.95 0.22) and extent of a lesion (3.85 0.42), and overall information (3.83 0.44), while thin-section spiral CT scans provided most information regarding its relationship with adjacent structures (3.56 0.50) and characterization of the lesion (3.51 0.61). Conclusion: SSD images and thin-section spiral CT scans can provide valu- able information for the evaluation of tracheobronchial disease. A spiral CT scanner can obtain a volumetric data set, and by means of vari- ous retrospective reconstruction techniques such as multiplanar recon- struction (MPR) imaging, multiplanar volume reconstruction imaging, three-dimensional (3-D) shaded-surface display (SSD) and virtual bronchoscopy, this can be displayed in a number of ways. The use of these techniques can lead to more accurate evaluation of tracheobronchial diseases. Two- and three-dimensional (2-D and 3-D) images are advantageous for the detection of mild stenoses and horizontal webs, evaluating the dimensions of an airway narrowing, and displaying congenital airway abnormalities (1 5). Conventional CT remains the “gold standard” in the imaging of airway disease, though endobronchial lesions in the central airway can be missed on routine thick-section CT (6 7). The purpose of our study was to evaluate the clinical utility of 2-D and 3-D spiral CT in tracheobronchial diseases by comparing it with chest radiography and routine thick-section CT and thin-section spiral CT. MATERIALS AND METHODS Between January 1994 and March 1999, 126 patients with known or suspected ab- Korean J Radiol 1(3), September 2000 135