Fig. 2

Dark-field and transmission signal grading of all nine human bodies for different regions of the lungs. Dot plot of median visual dark-field signal (a)/transmission (b) grading with 95% confidence interval on a 6-point ordinal scale (dark-field signal: 0 = no signal, 5 = maximum signal; transmission: 0 = effusion, 5 = normal lung) of all nine dark-field and transmission chest x-rays for reader 1. Dark-field signal increases from apex to base of the lung, whereas transmission shows no differences between upper, middle, and lower zones. Asterisks indicate statistical significance of median dark-field signal/transmission differences between the different zones in the left or right lobe. Associated null hypothesis probabilities in the dark-field modality for all readers are given in c. Non-significant differences (p > 0.050) are denoted by “ns”