Prenatal and/or childhood acid-suppressive medication use and risk of serious infections in children: A retrospective analysis of Taiwanese medical claims data.

USE is an imaging method based on tissue stiffness, relying on the propagation of high-frequency mechanical waves []. Tissue stiffness refers to its resistance to deformation under force, measured by stretching the material. “Deformation” indicates the change in length relative to the original length, while “stress” refers to force per unit area []. The strain ratio, a semi-quantitative stiffness index, compares the strain of a lesion within a region of interest (ROI) to that of an adjacent normal area. A ratio > 1 suggests the target lesion is less deformable and stiffer []. Tissue elasticity, defined as resistance to deformation and recovery after force removal, follows Hooke’s law: σ=Γ∙ε, where stress (σ) is the force per unit area, deformation (ε) is the strain, and the elastic modulus (Γ) relates stress to deformation [].