Author(s): Russell Wartchow, Jaxon Van Wagoner
Mentor(s): Brent Feland
Institution BYU
BACKGROUND: Shear wave elastography (SWE) is used to determine stiffness of soft tissue by analyzing the speed of shear waves as they are transmitted through the tissue. It remains unclear when using SWE whether there is a difference in consistency of measurement between quadriceps muscles (VL, RF, VL, and VI) and how the angle of measurement may influence results.l PURPOSE: Due to lack of information surrounding shear wave elastography regarding its accuracy, use, and best practices in a clinical setting, this study set out to find how measurement angle affects SWE of knee extensor muscles. METHODS: Data was collected from 7 participants (7 males: mean age 21.5 ± 1.5 yrs, ht = 182.38 ± 5.0 cm, wt= 84.5 ± 6.1 kg) in Provo, Utah, 2024. Subjects sat on a table with their knees hanging over the edge at 90 degrees. Maintaining this position, the VM, RF and VL were scanned with a GE Logiq S8 ultrasound 9L probe to measure SWE. This was replicated when placing the subject into 30 degrees of knee flexion. The midway point between the greater trochanter and the lateral epicondyle of the femur was measured and used to scan VL. Both VM and RF were scanned using the visual center of the muscle. Due to measurement inconsistencies VI was not scanned. The muscles analyzed were all assessed on three consecutive days, obtaining 5 data points from each muscle on each day. ANALYSIS: The consistency of measurements within each group (by muscle, angle and position) was calculated utilizing excel and SPSS v29 by calculating the mean and standard deviation of each kpa measurement and then calculating the coefficient of variation (CV) as the mean standard deviation. See graph for results (generated in ChatGPT). Lower CV values are indicative of more consistent measurements. RESULTS AND CONCLUSION: The coefficient of variation across 3 separate days for stiffness as measured by SWE was lowest for the VM at both angles of measurement. Overall, more variation exists in the VL than the RF but both exhibit greater variation in measurement, possibly due to the role of the RF as both a knee and hip agonist while the VL is significantly sensitive to knee joint changes and pennation changes with movement. Based on these results, measurement of the VM would help improve internal consistency of measurement when designing a study that looks at effects of injury or rehab on the quadriceps.