Imaging the airways has always been a difficult task. Since the introduction of high resolution computed tomography a lot has been achieved in this area, specially in the visualization of the small airways. With the fine details provided by this technique, morphological changes related to the bronchioles can now be detected in a way hitherto impossible. This study was aimed at the description of the CT scan signs of airway disease that were present in a group of 36 patients suffering from chronic respiratory symptoms of cough and great amount of sputum production (bronchial suppuration) attending the outpatient clinics of the Pulmonary Disease Service of the State University of Campinas School of Medicine. Among these patients, 12 were diagnosed as having cystic fibrosis, and 24, other diseases with chronic sputum production. The authors looked for the direct signs of airway disease, such as thickening of the wall and dilatation of the lumen of large airways and these same abnormalities, appearing as micronodules at the center of the lobule and branching linear opacities, or a combination of the two (the so-called "tree in bud" pattern), when the disease is predominantly located in the small airways, in the films obtained from all the patients. The indirect signs of small airway disease, like mosaic perfusion and air-trapping, were also analyzed. Imaging of the airways has come of age with the use of high-resolution computed tomography and there is little doubt that this technique is now the most sensitive radiographic method for imaging the small airways, this previously hidden area of the lungs.

Keywords: Computed tomography. High resolution computed tomography. Airway diseases. Bronchiolar diseases. Bronchiectasis.