Fig. 4From: The topical study of inhaled drug (salbutamol) delivery in idiopathic pulmonary fibrosisRelationship between pulmonary function and penetration index. Scatter plots of the relationship between FVC (L) and penetration index (PI) for: (a) 1.5 μm particle size (STAG), rho = 0.66667 p = 0.07099; (b) 6 μm particle size (STAG) rho = 0.59524 p = 0.11953; (c) nebulised rho = 0.92857 p = 0.00086. Linear regression analysis (line) is illustrated with its equation. FVC L: forced vital capacity in litres; rho: Spearman Rank Correlation CoefficientBack to article page