[A new technique for evaluating the respiratory tract--digital subtraction bronchography (DSBG)]

Bronchography is essential for evaluation of morphological changes in the bronchial tree. However, conventional bronchography using Propyliodone (Dionosil) is extremely invasive, especially to those with pulmonary infections. In the present study, we developed a new less invasive method of bronchography with the aid of digital subtraction technique (DSBG), and evaluated its clinical benefits. Bronchography was performed by injecting contrast medium (Iopamidol: Iopamiron 300) via the lumen of the bronchoscope (Olympus Type 20), and image processing of the respiratory tract was performed using digital subtraction technique. From 1991 to 1992, DSBG was performed in 15 cases (8 bronchiectasis, 1 diffuse panbronchiolitis, 1 lung cancer, 1 pulmonary emphysema, and 4 others). DSBG clearly demonstrated the morphological changes of large and segmental bronchial lesions in cases of bronchiectasis and lung cancer, as well as conventional bronchography using Dionosil. In addition, it was possible to image the morphological changes of bronchiolar lesions in diffuse panbronchiolitis and pulmonary emphysema to the same detail as obtained using classical selective alveolo-bronchography (SAB). Since DSBG can provide enhanced images the bronchial tree without being affected by cardiac and respiratory movements, we could obtain detailed information on bronchial and/or bronchiolar lesions. With respect to side effects, Iopamiron was quickly drained and/or absorbed within 2 hours after injection. Pulmonary infection and bronchial bleeding, which are well known primary complications of classical bronchography using Dionosil, were not observed. We conclude that 1) DSBG is useful new technique for examining morphological changes of the respiratory tract, and 2) DSBG is less invasive than conventional bronchography.