Chen et al. Fig. 4. Endotracheal tuberculosis in a 26-year-old woman. Posteroanterior chest radiograph shows segmental narrowing of the trachea (arrows). cases of congenital abnormality showed narrowing of air- ways. Lesions of the tracheobronchial tree varied from mild narrowing to complete obstruction, and from focal stenosis to diffuse narrowing. The mean scores of various techniques are summarized in Table 1, and the statistical differences between various pairs of techniques (permutations of RCT, TCT, MPR, and SSD) are summarized in Table 2. In general, in evaluating tracheobronchial disease, chest radiographs showed low values. In cases of pneumonecto- my or lesions at the level of the thoracic inlet, a score of 3 for localization and for detection was obtained in only two and four cases, respectively (Fig. 4). In terms of detection, localization, extent, relationship, characterization, and overall information, chest radiographs were significantly inferior to RCT, TCT, MPR, and SSD (p < 0.0001). For detection and localization of the lesion, SSD had the highest score, and was significantly superior to other CT techniques. It was inferior to TCT in only one case, in which the lesion was seen as a mild irregularity of the right main bronchus (Fig. 5). For MPR, the score was between that of TCT and SSD, and in34 cases (83%), the score for RCT was 3 or 4. Due to the small size of the endotracheal lesion, one case of RCT had a score of 1. With regard to extent, in 39 cases (95%), the score for RCT was 2 or 3. For TCT, a score of 3 or 4 was achieved in 37 cases (90%), and for both MPR and SSD, one of these A B Fig. 5. Endobronchial tuberculosis in a 67-year-old woman. A. Thin-section spiral CT shows mild irregular wall thickening (arrow) of the right main bronchus (score for detection = 4). B. SSD image shows subtle irregularity (arrow) in the right main bronchus (score for detection = 2). 138 Korean J Radiol 1(3), September 2000