HIGH-RESOLUTION COMPUTED-TOMOGRAPHY OF AIRWAY CHANGES AFTER INDUCED BRONCHOCONSTRICTION AND BRONCHODILATION IN ASTHMATIC VOLUNTEERS

Rationale and Objectives. We examined whether high-resolution computed tomography (HRCT) would detect and quantify induced airway changes in asthmatic volunteers. Methods. We performed pulmonary function tests and HRCT on eight asthmatic adults and two nonasthmatic control adults under three conditions: baseline, after methacholine inhalation, and after albuterol inhalation. Changes in pulmonary function, airway inte rnal luminal diameter (AILD), and airway wall thickness (AWT) in the t hree conditions were compared. Results. After methacholine inhalation, pulmonary function showed significant airflow obstruction in the asth matic volunteers compared with two nonasthmatic control volunteers. Th e median value for AILD decreased by 17% (p = .04). After subsequent i nhalation of albuterol, pulmonary function improved to above the basel ine levels in the eight asthmatic volunteers. The median value for AIL D increased by 18% above the baseline value (p = .0001). No changes in pulmonary function or AILD were seen in the two nonasthmatic voluntee rs. AWT did not change significantly in either the asthmatic or nonast hmatic volunteers after inhalation of methacholine or albuterol. Concl usion. HRCT can quantify changes in the internal luminal diameter of a sthmatic airways provoked by methacholine and albuterol inhalation.