CT and lung sound distribution findings for 2 representative cases of upper-lung-dominant emphysema.

Figure 3A to C: This subject was an 80-year-old male with GOLD III airflow limitation and an average %LAA of 47.6%. The inspiration CT showed upper-lung-dominant centrilobular emphysema (Figure 3A). After expiration, lower-lung volume tended to decrease more than upper-lung volume (Figure 3B). In this case, the lung sound intensity was lower-lung-dominant, and Lower QLD/Upper QLD was similar to the average value of healthy subjects (Figure 3C; Lower QLD/Upper QLD  = 3.17). Figure 3D to F: This subject was a 72-year-old male with GOLD II airflow limitation and an average %LAA of 44.1%. Inspiration CT showed upper-lung-dominant centrilobular emphysema (Figure 3D). After expiration, the decreases in the upper- and lower-lung volumes were almost equal (Figure 3E). In this case Lower QLD/Upper QLD was lower than average values in the COPD patients (Figure 3F; Lower QLD/Upper QLD  = 1.49).