Fig. 5.
Magnitude (top), local frequency estimation (LFE) elastogram (middle) and optical (bottom) images of injured lungs for pressures of 0, 3, 10, 15, 20, and 25 cm H2O. At pressures of 15 cm H2O and less, little change in shear stiffness is observed. Beyond 15 cm H2O, lung volume increases with a corresponding increase in global shear stiffness. At 25 cm H2O, regional increases in shear stiffness are observed around and radiating from the two bronchii within the imaging slice, indicating that prestress within the relatively rigid airway wall is being communicated to the surrounding parenchyma.