Supersonic Shear Imaging for Quantification of Lateral Abdominal Muscle Shear Modulus in Pediatric Population with Scoliosis: A Reliability and Agreement Study

The aim of this study was to assess the intra- and inter-rater reliability/agreement of the lateral abdominal muscle (LAM) stiffness and thickness measurements at rest and during contraction and to determine the relationship between the superficial fat thickness and the LAM stiffness measurements. LAM stiffness and thickness were measured using supersonic shear wave elastography (SSI) in pediatric participants. The reliability of LAM stiffness and thickness measurements ranged from moderate to excellent. There was an inverse correlation between fat thickness and between-rater difference in the resting external oblique stiffness (r > -0.37) and the contracted external and internal oblique stiffness (r > -0.40). SSI is a reliable method for assessing LAM stiffness and thickness in pediatric populations. To remove potential systematic errors: (i) the first round of measurements should be performed to familiarize patients with procedures; (ii) the examiner should pay more attention while performing LAM measurements on the opposite side of the body.