PURPOSE: To evaluate longitudinal change of low attenuation area (CT-detected emphysema) on low-dose spiral CT images.
METHODS: 118 male CT-detected emphysema cases with smoking history (mean 40 pack-years) were evaluated with low-dose spiral CT screening images and pulmonary function test. The proportion of low attenuation area among whole CT images (%LAA, below -910 H.U.)were calculated automatically with software(“riskPointer”, Hitachi Medical Co.ltd).
RESULTS: Only 27 cases (23%) showed significant obstructive impairment at baseline. Between baseline and recent screening (mean follow-up periods; 4.9 years), overall %LAA had increased from 7.9% to 11.3%. The augmentation of % LAA were not significantly different with or without obstructive impairment at baseline. Participants whom quit smoking at baseline (n=22) had less augmentation of %LAA (1.7%) compared with smokers at baseline (3.8%).
CONCLUSION: CT-detected emphysema is progressive, with or without obstructive impairment. Prolonged quit smoking may effective to suppress the progression of pulmonary emphysema.
CLINICAL IMPLICATIONS: Low-dose spiral CT screening may play a role to detect and early intervention for subclinically chronic obstructive pulmonary disease.
DISCLOSURE: Takeshi Nawa, Grant monies (from sources other than industry) Ministry of health, labour and welfare, Japan; Product/procedure/technique that is considered research and is NOT yet approved for any purpose, The software (“riskPointer”) had been developed by Hitachi Medical Co. Ltd.