기흉 크기 계산기 (Pneumothorax Percentage by Collins Method)

Collins Method: 기흉 % = 4.2 + 4.7 × (A + B + C)
A: 폐 꼭대기(apex)에서 측정한 간격 (cm)
B: 폐 상반부 중간(middle of upper half)에서 측정한 간격 (cm)
C: 폐 하반부 중간(middle of lower half)에서 측정한 간격 (cm)

Small Pneumothorax (< 20%)
Moderate Pneumothorax (20–40%)
Large Pneumothorax (> 40%)

Reference :
Collins CD, Lopez A, Mathie A, et al. Quantification of pneumothorax size on chest radiographs using interpleural distances: regression analysis based on volume measurements from helical CT. AJR Am J Roentgenol. 1995;165(5):1127-1130.