Multidetector row computed tomography quantification of bronchiolitis obliterans syndrome after hematopoietic stem cell transplantation: A pilot study

PURPOSE: To evaluate multidetector row computed tomographic indexes to quantify bronchiolitis obliterans syndrome (BOS) after hematopoietic stem cell transplantation by correlation with pulmonary function tests (PFT). MATERIALS AND METHODS: Eighteen patients with BOS after hematopoietic stem cell transplantation and 18 age-matched healthy volunteers were included. They underwent multidetector row computed tomography including inspiration and expiration scans. The patients also underwent PFTs. Mean lung density (MLD), relative areas (RAs) of lung with attenuation coefficients below specific thresholds, and 9 percentiles of the distribution of attenuation coefficients were computed. These parameters and PFT results were correlated. RESULTS: Mean MLD on inspiration (MLDin), MLD on expiration (MLDex), and the difference between the 2 (ΔMLD) were -858.5 HU, -788.6 HU, and 69.9, respectively, for the patients and -815.9 HU, -691.8 HU, and 124.1, respectively, for the volunteers. These parameters showed significant differences between the 2 groups (P<0.001) and strongly correlated with patients' residual forced expiratory volume in 1 second (FEV1) (r=0.71, 0.92, and 0.85, P≤0.001, respectively). RA with attenuation coefficients <-800 HU (RA800e) and the 80th percentile (80the) on expiration correlated most highly with the patients' residual FEV1 (r=-0.94, P<0.001). CONCLUSIONS: RA with attenuation coefficients <-800 HU (RA800e) and the 80th percentile (80the) on expiration are valid indexes of the patients' residual FEV1 in BOS.