Pulmonary sarcoidosis: morphologic associations of airflow obstruction at thin-section CT.

Abstract

To identify relationships between the obstructive defects of pulmonary sarcoidosis and the computed tomographic (CT) patterns of disease. CT scans obtained in 45 patients were scored semiquantitatively for extent of five CT patterns, and the functional importance of each pattern was evaluated. The most prevalent CT patterns were decreased attenuation (n = 40), a reticular pattern (n = 37), and a nodular pattern (n = 36). At univariate and multivariate analyses, a reticular pattern was the main determinant of functional impairment, particularly airflow obstruction. The extent of a reticular pattern was independently associated with airflow obstruction, as shown by the inverse relationships with the forced expiratory volume in 1 second (FEV1) (P < .001), FEV1-forced vital capacity ratio (P < .01), maximum expiratory flow at 25% above residual volume (P < .001), and maximum expiratory flow at 50% above residual volume (P < .001) and the positive relationship with the residual volume-total lung capacity ratio (P < .001). In sarcoidosis, CT features compatible with small airways disease are common but contribute little to airflow obstruction, particularly in more advanced disease, which is characterized by an extensive reticular pattern. A reticular pattern at CT is the major morphologic association of airflow obstruction.