T Beinert1, P Kohz, M Seemann, T Egge, M Reiser, J Behr. 1. Universitäts-Klinikum Charité, Zentrum für Innere Medizin, Medizinische Klinik und Poliklinik II, Schumannstr. 20-21, Berlin D-10117, Germany.
Abstract
STUDY OBJECTIVE: Lung density assessed by high resolution computed tomography (HRCT) is sufficiently sensitive for the diagnosis of interstitial lung disease, but may be hampered by uneven disease distribution. We determined the mean and subpleural density values in patients with diffuse fibrosing alveolitis (FA) and evaluated the diagnostic accuracy of both parameters, expressed as post-test odds ratios. MATERIALS AND METHODS: Pulmonary HRCT was performed on 21 FA patients and compared to scans of 27 healthy volunteers. The HRCT procedure was standardized by taking 3 scans at the carina +/- 5 cm, and by defining inspiration levels at 50% vital capacity. Mean lung density (MLD) and subpleural lung density (SLD) were calculated for all participants. RESULTS: MLD and SLD values for healthy subjects were significantly higher compared with the patient group. Odds ratios were 7.8:1 and 3.9:1 for SLD and MLD, respectively, demonstrating a superior discrimination power of SLD in the diagnosis of FA. CONCLUSION: Diagnostic accuracy of quantitative HRCT measurements in FA was improved by the separate evaluation of subpleural lung density, which is a better indicator of the presence or absence of lung fibrosis than is mean lung density.
STUDY OBJECTIVE: Lung density assessed by high resolution computed tomography (HRCT) is sufficiently sensitive for the diagnosis of interstitial lung disease, but may be hampered by uneven disease distribution. We determined the mean and subpleural density values in patients with diffuse fibrosing alveolitis (FA) and evaluated the diagnostic accuracy of both parameters, expressed as post-test odds ratios. MATERIALS AND METHODS: Pulmonary HRCT was performed on 21 FA patients and compared to scans of 27 healthy volunteers. The HRCT procedure was standardized by taking 3 scans at the carina +/- 5 cm, and by defining inspiration levels at 50% vital capacity. Mean lung density (MLD) and subpleural lung density (SLD) were calculated for all participants. RESULTS:MLD and SLD values for healthy subjects were significantly higher compared with the patient group. Odds ratios were 7.8:1 and 3.9:1 for SLD and MLD, respectively, demonstrating a superior discrimination power of SLD in the diagnosis of FA. CONCLUSION: Diagnostic accuracy of quantitative HRCT measurements in FA was improved by the separate evaluation of subpleural lung density, which is a better indicator of the presence or absence of lung fibrosis than is mean lung density.