AB1819-HPR INTRA-RATER RELIABILITY OF SHEAR WAVE ELASTOGRAPHY FOR THE QUANTIFICATION OF THUMB MUSCLE ELASTICITY

Abstract

BackgroundShear wave elastography (SWE) is a technique that evaluates tissue elasticity by applying an acoustic radiation force impulse [1]. It is undetermined how reliable this modality is in assessing thumb muscles. Quantitative evaluation of muscle stiffness in conditions such as trapeziometacarpal osteoarthritis where increased fibrosis, muscle tone, spasm, and contractures can be seen can provide important information about the pathophysiology and prognosis of the diseases [2].ObjectivesThis study aimed to assess the intra-rater reliability of thumb muscle elasticity and thickness in healthy people.MethodsTen healthy participants (20 hands) enrolled in the study. Thickness and shear wave velocity (SWV) of adductor pollicis (AdP) and first dorsal interosseous (FDI) muscles were obtained using an ACUSON S3000 Ultrasonography System and a 9L4 probe (4-9 MHz) (Siemens Medical Solutions, Mountain View, California). Ultrasound data (SWV, thickness) were collected and analyzed by an experienced radiologist. Three repeated SWV and thickness measurements were recorded in the resting position and an average was taken. Two sessions were performed at a 15-minutes interval.ResultsTen healthy participants (20 hands; 5 female; 5 male; mean age: 25.9±2.68 years; BMI: 22.4±1.39 kg/m2) were included in this study. Nine subjects had right-hand dominancy and 1 had left-hand dominancy. The mean (±SEM) shear wave velocity for the AdP was 1.86 ± 0.6 m/s (=10.86 kPa), and for the FDI was 1.76 ± 0.5 m/s (=9.72 kPa). The intra-rater trial agreement was excellent, with intraclass correlation coefficients of 0.887 and 0.828 respectively. The mean (±SEM) muscle thickness for the AdP was 12.4 ± 3.93 mm, and for the FDI was 12.0 ± 3.68 mm. The intra-rater trial agreement was excellent, with intraclass correlation coefficients of 0.953 and 0.984 respectively.ConclusionSWE ultrasound was a reliable imaging technique to assess the stiffness and thickness of thumb muscles.