Reliability of Panoramic Ultrasonography in Assessing Pectoralis Minor Morphology: An Intra- and Inter-Rater Study Among Asymptomatic Adults

Objectives: This study aimed to examine the intra- and inter-rater reliabilities of panoramic ultrasonographic measurements of the length (Pm_L), thickness (Pm_T), and cross-sectional area (Pm_CSA) of the pectoralis minor (Pm). Methods: Twenty young male participants (mean age: 22.9 ± 3.8 years) were recruited for this study. All participants had asymptomatic rounded shoulder posture (RSP), with a mean acromion-to-table distance of 59.316 ± 9.631 mm. Longitudinal panoramic scans of the Pm of the dominant arm were acquired 3 trials of 4 measurements for all participants. The first two measurements were examined by the same rater on the same day, and the third measurement was performed by a different rater. The same procedure was carried out by the first rater after 30 days for inter-day reliability. Intraclass correlation coefficients (ICC), standard errors of measurement (SEM), and minimal detectable changes (MDC) were calculated to estimate the reliabilities. Results: The intra- and inter-rater reliabilities of Pm_L, Pm_T and Pm_CSA were excellent (all ICC > 0.932; all SEM < 7.4%; all MDC < 20%). Bland-Altman plots demonstrated good agreement with nearly zero mean differences between measurements. Conclusion: Using panoramic ultrasonography to measure Pm_L, Pm_T and Pm_CSA may be considered a reliable method with excellent inter-day, intra- or inter-rater reliabilities.