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Updated: May 31, 2026

Automated Measurement of Pulmonary Emphysema and Small Airway Remodeling in Cigarette Smoke-exposed Mice
Published on: January 16, 2015
Reduced-dose chest CT with 3D automatic exposure control vs. standard chest CT: quantitative assessment of
Hisanobu Koyama1, Yoshiharu Ohno, Youichi Yamazaki
1Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, Japan. hkoyama@med.kobe-u.ac.jp
Objectives:
To determine the capability of reduced-dose chest CT with three-dimensional (3D) automatic exposure control (AEC) on quantitative assessment of emphysematous change in smoker' lung parenchyma, compared to standard chest CT.
Methods:
Twenty consecutive smoker patients (mean age 62.8 years) underwent CT examinations using a standard protocol (150 mAs) and a protocol with 3D-AEC. In this study, the targeted standard deviations number was set to 160. For quantitative assessment of emphysematous change in lung parenchyma in each subject using the standard protocol, a percentage of voxels less than -950 HU in the lung (%LAA(-950)) was calculated. The 3D-AEC protocol's %LAA was computed from of voxel percentages under selected threshold CT value. The differences of radiation doses between these two protocols were evaluated, and %LAAs(-950) was compared with the 3D-AEC protocol %LAAs.
Results:
Mean dose length products were 780.2 ± 145.5 mGy cm (standard protocol), and 192.0 ± 95.9 (3D-AEC protocol). There was significant difference between them (paired Student's t test, p<0.00001). Meanwhile, only setting -960 HU yielded no significant difference (paired Student's t test, p=0.32) between %LAAs(-950) and 3D-AEC protocol %LAAs. In adopting the feasible threshold CT values of the 3D-AEC protocol, the 3D-AEC protocol %LAAs were significantly correlated with %LAAs(-950) (r = 0.98, p<0.001) and limits of agreement from Bland-Altman analysis was 0.52 ± 4.3%.
Conclusions:
Changing threshold CT values demonstrated that reduced-dose chest CT with 3D-AEC can substitute for the standard protocol in assessments of emphysematous change in smoker' lung parenchyma.
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