One year follow-up of lung clearance of Tc-99m-diethylene triamine penta-acetic acid and disease activity in sarcoidosis

Background and aim of the work: In interstitial lung disease lung clearance of Tc-99m-diethylenetriaminepentaacetic acid (DTPA) reflects alterations i n the alveolar capillary barrier. Our objective was to describe changes in lung clearance during one year in sarcoidosis, and to relate clearance to o ther data of lung function and disease activity. Methods: Twenty-three newl y diagnosed patients were studied with respect to lung DTPA clearance, spir ometry, Ga-67 scintigraphy and serum angiotensin converting enzyme (SACE). Lung mechanics and arterial PO2 at rest and exercise were studied in patien ts with radiological parenchymal changes. Six of these patients were prescr ibed peroral steroids. Results: At inclusion lung DTPA clearance measured o ver 30 minutes was 53 +/- 16 minutes and at follow-up 59 +/- 20 minutes (p > 0.05). The number of pathological clearance curves at inclusion was 10 an d at follow-up 6. In treated patients lung DTPA clearance improved as did l ung Ga-67 score and SAGE. However, lung clearance did not correlate signifi cantly with changes in lung function or other activity parameters. Conclusi ons: Lung DTPA clearance reflects lung function from an aspect different fr om that of other methods, It seems sensitive to pathology reversed by stero ids and may, in some cases, help in the evaluation of disease activity.