BRONCHIOLITIS OBLITERANS AFTER LUNG TRANSPLANTATION - DETECTION USINGEXPIRATORY HRCT

Objective: The objective of this study was to determine if air trappin g, as detected on expiratory high-resolution CT (HRCT), is useful as a n indicator of bronchiolitis obliterans (BO) in lung transplant recipi ents. Materials and methods: Corresponding inspiratory and expiratory HRCT images at five different levels and spirometry were obtained in 2 1 lung transplant recipients. Eleven patients had BO proved by transbr onchial biopsy specimens; the remaining 10 patients had no pathologic or functional evidence of airways disease, Two ''blinded'' observers a ssessed the inspiratory images for the presence of bronchiectasis and mosaic pattern of lung attenuation, and the expiratory images for pres ence and extent of air trapping, Statistical comparison of the frequen cy of HRCT findings between patients with and without BO was performed using Fisher's Exact Test. Results: On inspiratory images, bronchiect asis and mosaic pattern of lung attenuation mere present in 4 (36%) an d 7 (64%) of 11 patients with BO, and 2 (20%) and 1 (10%) of 10 patien ts without BO (p>0.05 and p<0.05), respectively, The sensitivity, spec ificity, and accuracy of bronchiectasis and mosaic pattern for BO were 36%, 80%, and 57%, and 64%, 90%, and 70%, respectively, On expiratory images, air trapping was found in 10 of 11 (91%) patients with BO com pared to 2 of 10 (20%) patients without BO (p<0.002). Air trapping was found to have a sensitivity of 91%, specificity of 80%, and accuracy of 86% for BO. Air trapping was identified in one patient with BO who had normal results of baseline spirometric function tests. Conclusion: Air trapping, as detected on expiratory HRCT, was the most sensitive and accurate radiologic indicator of BO in the lung transplant populat ion.