Validation of Panoramic Ultrasound Measurement of the Cross-Sectional Area of the Vastus Medialis

Minnehan, KS, Dexter, WW, Holt, CT, Scharnetzki, L, Alex, JP, Chin, KE, and Kokmeyer, DJ. Validation of panoramic ultrasound measurement of the cross-sectional area of the vastus medialis. J Strength Cond Res 37(1): 41-45, 2023-The cross-sectional area (CSA) of the vastus medialis (VM) is an independent predictor of important clinical outcomes in musculoskeletal conditions of the knee, such as pain and long-term function. Previous studies validated ultrasound (US) to measure larger muscles of the thigh, but this approach has limited accuracy in measuring smaller muscles, such as the VM. In this study, we aimed to validate panoramic US measurements of the CSA of the VM and compare the results with those from the gold standard of magnetic resonance imaging (MRI) (significance set p ≤ 0.05). In this retrospective, single-center study, we compared pairs of US and MRIs taken of 25 adults who participated in a 10-week study of non-weight-bearing activity at a National Aeronautics and Space Administration facility. Images were acquired from various locations on the right thigh at multiple time points. Two researchers independently analyzed the US and MRI pairs by outlining the intermuscular border of the VM in the most distal image. We found excellent agreement between the US and MRI measurements of the CSA of the VM analyzed by researcher 1 (interclass correlation coefficient [ICC]: 0.997) and researcher 2 (ICC: 0.980). We also found excellent agreement for interrater reliability for MRI (ICC: 0.988) and US (ICC: 0.982) and intrarater reliability for US for researcher 1 (ICC: 0.999) and researcher 2 (ICC: 0.996). Our findings demonstrate that US is a valid and reliable tool for measuring the CSA of the VM compared with MRI.