Volume rendering of the tracheobronchial tree: clinical evaluation of bronchographic images

To evaluate the application of the volume-rendering technique to airway disease.

Seventy-four spiral computed tomographic (CT) examination (1- to 5-mm section thickness; pitch, 1.7-20.0) were performed for known or suspected abnormality of the airways, including (a) benign tracheobronchial stenosis (group 1, n = 47), (b) complex airway lesions (group 2, n = 15), and (c) bronchiectasis (group 3, n - 12). Two radiologists independently compared overlapping transverse CT scans and volume-rendered bronchographic images for detection of airway abnormalities and identification of lesion morphology and extent, with bronchoscopic correlation.

Bronchographic image quality was graded as excellent (73%) or good (24%), whereas motion-related artifacts led to poor image quality in 3% of cases (trapezoid parameters included window width of -700 to -350 HU, triangular trapezoid shape, parenchymal opacification of 70%, unshaded algorithm). Compared with transverse CT scans, volume-rendered images (a) provided supplemental group 3, even, seven), (b) improved confidence in the interpretation of congenital airway abnormalities in six cases (8%) (all from group 2), and (c) corrected interpretive errors in four cases (5%) (group 1, two cases; group 2, two).

Volume-rendered images improved the recognition of mild changes in airway caliber and the understand of complex tracheobronchial anomalies.