Diagnosis of bronchiolitis obliterans in heart-lung transplantation patients: importance of bronchial dilatation on CT.

OBJECTIVE: The purpose of this study was to evaluate the significance of bronchial dilatation identified on high-resolution CT scans obtained after heart-lung transplantation. Bronchial dilatation has been identified on pathologic specimens and on high-resolution CT scans of patients with severe bronchiolitis obliterans after lung transplantation, but this finding has not previously been systematically studied as a manifestation of this complication. MATERIALS AND METHODS: We studied the high-resolution CT scans of 16 patients who had had heart and lung transplantation at least 1 year before, and compared the percentage of dilated bronchi with evidence of small airways disease shown on pulmonary function tests. RESULTS: We found a close correlation between the percentage of bronchi in the lower lobes that were dilated and the percent predicted forced expiratory volume in 1 sec, forced vital capacity, and forced expiratory flow between 25% and 75% of vital capacity. No other feature identified on high-resolution CT scans correlated with pulmonary function abnormalities. CONCLUSION: We conclude that dilatation of the lower lobe bronchi is a good indicator of bronchiolitis obliterans in this population, and that the percentage of dilated bronchi generally increases with increasing pulmonary dysfunction.