Fig. 2

Definition of displacement and global strain. (A) Inter-frame vertical and horizontal displacement curves (top), cumulative vertical and horizontal displacement curves (bottom), and a schematic diagram of peak-to-peak extraction of the right diaphragm during one respiratory cycle. (B) Global strain curve of the right diaphragm and a schematic diagram of peak-to-peak extraction. The red region in the ultrasound image is the diaphragm area