Evaluation of Obstructive Pulmonary Function Impairment Risks in Pulmonary Emphysema Detected by Low-Dose CT: Compared with Simple Digital Radiography

Abstract

Background: Pulmonary emphysema (PE) is major cause of obstructive pulmonary function impairment (OPFI), which is diagnosed by spirometry. PE by high resolution CT is known to be correlated with OPFI. Recently, low dose CT (LDCT) has been increasingly used for screening interstitial lung diseases including PE. The aim of this study was to evaluate OPFI risks of subjects with PE detected by LDCT compared with those detected by simple digital radiography (SDR). Methods: LDCT and spirometry were administered to 266 inorganic dust exposed retired workers, from May 30, 2007 to August 31, 2008. This study was approved by our institutional review board and informed consent was obtained. OPFI risk was defined as less than 0.7 of forced expiratory volume in one second (FEV1)/forced vital capacity (FVC), and relative risk (RR) of OPFI of PE was calculated by multiple logistic regression analysis. Results: Of the 266 subjects, PE was found in 28 subjects (10.5%) by LDCT and in 11 subjects (4.1%) by SDR; agreement was relatively low (kappa value=0.32, p＜0.001). FEV1 and FEV1/FVC were significantly different between PE and no PE groups determined by either SDR or LDCT. The differences between groups were larger when the groups were divided by the findings of SDR. When PE was present in either LDCT or SDR assays, the RRs of OPFI were 2.34 and 8.65, respectively. Conclusion: LDCT showed significantly higher sensitivity than SDR for detecting PE, especially low grade PE, in which pulmonary function is not affected. As a result, the OPFI risks in the PE group by LDCT was lower than that in the PE group by SDR.

Relation of Pulmonary Function Impairment and Coronary Artery Calcification by Multi-detector Computed Tomography in Group Exposed to Inorganic Dusts

“…If prospective studies are performed in large number of subjects with statistical power of tests in the future, more meaningful results would be obtained. Second, the authors didn't consider the fact that the pulmonary emphysema findings diagnosed on digital chest imaging would increase the risk of OPFI22. However, the interpretation of the results in this study would be reasonable because this study was focused on the relationship between CAC and PFI.…”