Conventional High-resolution CT Versus Contiguous Multidetector CT in the Detection of Bronchiolitis Obliterans Syndrome in Lung Transplant Recipients

OBJECTIVE: To compare the detection rate of pulmonary abnormalities between conventional high-resolution computed tomography (HRCT) and high-resolution multidetector computed tomography (MDCT) in lung transplant recipients and to correlate a composite computed tomography (CT) score with bronchiolitis obliterans syndrome (BOS) stage. METHODS: Twenty-four lung transplant recipients (12 single/12 double lung transplants, 13 males/11 females, mean age: 53 y, range: 28 to 71) underwent contiguous 16-slice high-resolution MDCT of the lungs at maximal inspiration and maximal expiration. Eight reformatted image sets were reconstructed: (i) contiguous 1-mm slice MDCT image set in the transverse, sagittal, and coronal image planes at maximal inspiration; (ii) contiguous 1-mm slice MDCT image set in the transverse, sagittal, and coronal image planes at maximal expiration; (iii) conventional HRCT image set of 1-mm slices every 10 mm at maximal inspiration; and (iv) conventional expiratory HRCT of 1-mm slices at 3 selected levels at maximal expiration. Individual pulmonary abnormalities were added to give a composite CT score. Individual abnormalities and the composite CT score were correlated with BOS stage, as based on functional testing of airflow obstruction, for each of the 8 image sets. RESULTS: Transverse, sagittal, and coronal MDCT correlated significantly with BOS stage (R=0.46, 0.49, 0.52, respectively), whereas conventional HRCT did not. Multiple regression analysis demonstrated that transverse MDCT was the only independent predictor of BOS stage (R=0.33, P<0.01). Interobserver agreement for composite CT scores for HRCT, transverse, sagittal, and coronal MDCT were R2=0.89, 0.87, 0.83 and 0.80, respectively. Interobserver agreement for individual abnormalities was better with MDCT than with conventional HRCT. CONCLUSIONS: In lung transplant recipients, high-resolution MDCT detects significantly more pulmonary abnormalities and has better interobserver agreement than conventional HRCT and is an independent predictor of BOS stage.