Early bronchiolitis obliterans following lung transplantation: Accuracy of expiratory thin-section CT for diagnosis

PURPOSE: To evaluate the accuracy of thin-section computed tomography (CT) with expiratory scans in diagnosing early bronchiolitis obliterans after lung transplantation. MATERIALS AND METHODS: Thin-section CT scans were reviewed by two observers blinded to the diagnoses in seven consecutive lung transplant recipients with histopathologically proved bronchiolitis obliterans (group A) and 21 with normal biopsy findings (group B). All patients had normal biopsy and stable pulmonary function test (PFT) results 2-36 weeks prior to CT. Patients with normal biopsy results were placed into subgroups based on abnormal (group B1) or stable (group B2) PFT results. Air- trapping extent on expiratory scans was scored on a 24-point scale. RESULTS: The mean air-trapping score in group A (6.6) was not significantly different from that in group B (4.5, P = .17). The air-trapping score was significantly higher in groups A and B1 than in group B2 (6.2 and 2.6, respectively; P = .03). The frequency of an air-trapping score of 3 or more in groups A and B1 was significantly higher than that in group B2 (P = .03). By using a score of 3 or more to indicate air trapping, the sensitivity of expiratory CT was 74%, specificity was 67%, and accuracy was 71%. CONCLUSION: Thin-section CT, including expiratory scans, is of limited accuracy in diagnosing early bronchiolitis obliterans after lung transplantation.