Muscle size assessment with panoramic ultrasound: measurement reliability among varying body masses

Abstract

Panoramic ultrasound (US) has recently been suggested as a reliable means of assessing muscle cross‐sectional area (CSA) with high intra‐day reliability between images. However, neither inter‐day reliability nor intra‐day reliability across populations with significantly different body masses has been examined. Therefore, the purpose of this study was to examine both intra‐ and inter‐day reliability measures of the CSA of the vastus lateralis (VL) in participants with varying body masses. 15 participants (age 20.7 ± 1.1 yrs) were divided into three groups according to mass: group A (59.6 ± 7.4 kg), group B (77.5 ± 8.1 kg), and group C (101.8 ± 8.9 kg). Three images taken at the mid‐thigh were obtained on three different days. The CSA was measured for each image using manual planimetry and the coefficient of variation (CV) was calculated. The intra‐day CV for groups A, B, and C was 1.70 ± 0.60, 1.71 ± 0.70, and 1.67 ± 0.95, respectively. The inter‐day CV was similar for groups A and B (4.07 ± 1.96 and 4.07 ± 2.48 respectively), but slightly higher (5.63 ± 2.36) for group C. These results are similar to previous research, suggesting that intra‐day reliability of panoramic US images measuring CSA is high. However, lower inter‐day reliability of the current method suggests caution should be taken when using panoramic US in longitudinal studies where small changes in muscle size may occur. Funding: TU CR&I