Original ArticlesMixed Infiltrative and Obstructive Disease on High-Resolution CT Differential Diagnosis and Functional Correlates in a Consecutive SeriesChung, Myung Hee M.D; Edinburgh, Keith J. M.D; Webb, Emily M. M.D; McCowin, Marcia M.D; Webb, W. Richard M.DAuthor Information From the Department of Radiology (M.H.C.), Holy Family Hospital, Catholic University of Korea, Kyunggi-do, Korea, the Department of Radiology (K.J.E.), North Memorial Medical Center, Minneapolis, MN, and the Department of Radiology (M.M., W.R.W.), University of California, San Francisco, CA. Address correspondence and reprint requests to W. Richard Webb, M.D., Department of Radiology, M396, University of California, San Francisco, San Francisco, CA 94143–0628; e-mail: [email protected] Journal of Thoracic Imaging: April 2001 - Volume 16 - Issue 2 - p 69-75 Buy Abstract Fourteen of 400 consecutive patients having high-resolution computed tomography (HRCT) with expiratory images showed findings of infiltrative lung disease on inspiratory HRCT and air trapping on expiratory CT. Diagnoses included hypersensitivity pneumonitis, sarcoidosis, atypical infection, and pulmonary edema. The extent of infiltrative abnormalities and air trapping were correlated with pulmonary function tests (PFT) in 11 patients. PFT indicated a mixed pattern in five, an obstructive pattern in three, and a restrictive pattern in three. Forced expiratory volume (FEV) in 1 second/forced vital capacity (FVC) correlated significantly with the extent of air-trapping (r = 0.60; p = 0.05). The extent of infiltrative abnormalities correlated significantly and negatively with forced vital capacity (r = −0.82, p = 0.002), FEV1 (r = −0.59, p = 0.05), total lung capacity (TLC) (r = −0.67, p = 0.05), and DLCO (r = −0.75, p = 0.02). Findings of lung infiltration on inspiratory HRCT scans and air trapping on expiratory CT correlated respectively with PFT measures of restrictive and obstructive lung disease. © 2001 Lippincott Williams & Wilkins, Inc.