LUNG-FUNCTION AND DISEASE-ACTIVITY IN SARCOIDOSIS - DISEASE-ACTIVITY IN SARCOIDOSIS

In sarcoidosis the lung clearance of inhaled Tc-99m-labelled diethylen e triamine pentaacetic acid (DTPA) is often abnormal. Few studies rela ted the lung clearance of Tc-99m-DTPA to the results of other lung fun ction tests and/or disease activity parameters. This study describes t he relationship in sarcoidosis between the lung clearance of Tc-99m-DT PA measured over 180 minutes, and a set of function tests comprising l ung volumes and lung mechanics as well as arterial blood gases. Diseas e activity was assessed with serum angiotensin-converting enzyme (SACE ) and Ga-67 scintigraphy. Measurements of lung clearance, spirometry a nd SACE were thus performed in 41 never-smoking patients with radiolog ic signs of intrathoracic sarcoidosis. In 32 patients a Ga-67 scan was obtained. The clearance of Tc-99m-DTPA was abnormal in 23 patients. E ither an abnormally fast mono-exponential clearance or a bi-exponentia l clearance course was disclosed. In 17 of these patients, dynamic spi rometry was normal. The Ga-67 scan was abnormal in 15 patients. There was a significant association between abnormal lung clearance of Tc-99 m-DTPA and abnormal pulmonary uptake of Ga-67. This suggests that lung clearance of Tc-99m-DTPA may be used as a means for assessing disease activity in pulmonary sarcoidosis.