According to diagnoses of pulmonary emphysema, many studies have suggested a relationship between the degree of low attenuation area (LAA) and pulmonary function. We developed an automated analysis system of LAA on Low-dose spiral CT (LDCT). The purpose of this study is to determine the correlation between LAA on LDCT and pulmonary function.
80 participants (50 current smokers and 30 ex-smokers men, Brinkman index mean is 795.5 and mean age is 55.9) underwent LDCT. Those suspected of having LAA on LDCT were those who need high resolution CT for further examination. This automated system selects LAA as a candidate of pulmonary emphysema considering the threshold of pulmonary parenchyma. We established the threshold at −900HU in this study. We compared the area of LAA to the results of pulmonary function tests, including FEV1%(Gaensler) and FEV1%predicted to assess airway obstruction.
The means of FEV1% and FEV1%predicted were 70.8% and 84.3% respectively. The mean of LAA was 14.14% (from 0.39 to 32.68%). The correlation coefficient between FEV1% and LAA was -0.57 and also between FEV1%predicted and LAA was -0.45.
This system was effective to objectively estimate the degree of pulmonary function of the pulmonary emphysema.
Our data suggest that LDCT on the health check-up is a useful tool in early detection of pulmonary emphysema when we use the appropriate analysis system of it.
S. Kusano, None.