High-resolution CT findings of bronchiolitis obliterans syndrome after hematopoietic stem cell transplantation.

PurposeTo describe the high-resolution computed tomography (CT) findings occurring in bronchiolitis obliterans syndrome (BOS) after hematopoietic stem cell transplantation (HSCT) and to determine the relationship between pulmonary function tests (PFTs) and air trapping detected on expiratory CT.Materials and methodsThe high-resolution CT scans of 33 patients who underwent HSCT and subsequently developed BOS were evaluated by 2 observers blinded to PFT results. Scans were ranked for degree of air trapping and scored for findings of bronchial wall thickening, bronchiectasis, and centrilobular opacities. Air-trapping rank was correlated with the degree of airflow obstruction as determined by PFTs.ResultsThe ranking of air trapping correlated significantly with 1-second forced expiratory volume (P=0.001), 1-second forced expiratory volume/forced vital capacity (PConclusionsIn BOS developing after HSCT, air trapping is the principal finding on CT, and its severity correlates with PFTs. Bronchial wall thickening is common, but almost always mild; bronchiectasis and centrilobular opacities occur in less than half of cases and are also mild.