Figure 3:

Corresponding proton density difference maps computed as RV minus TLC and ³He MR images in, A, a representative healthy volunteer, B, a representative patient with asthma (FEV₁ = 60% predicted), and, C, a representative patient with severe emphysema (FEV₁ = 19% predicted). ¹H signal difference is expressed as a percentage of the mean heart signal; ³He signal intensity is expressed as a percentage of the maximum ³He lung value. D, Correlation analysis between ¹H signal change and ³He signal intensity in the overall population (R² = 0.61). Data are expressed respectively in percentage respect to the mean heart signal and to the maximum ³He value within the lung. Dotted lines = 95% confidence intervals for the regressions. Color spectra indicate the ¹H signal difference as a percentage of the mean heart signal.