Study design: Systematic review.
Objective: To systematically review the literature on the rater reliability of Rehabilitative Ultrasound Imaging (RUSI) measurements to assess the morphology of the abdominal and lumbar trunk musculature.
Summary of background data: RUSI is an increasingly popular method of evaluating the morphology and function of muscles with real-time ultrasound. Conclusions regarding the reliability of measurements obtained by RUSI, need to be established before recommending its wider use.
Methods: A systematic approach to searching and identifying original research articles reporting quantitative RUSI measurements was undertaken. Reliability data were extracted and methodologic quality was evaluated by 2 independent reviewers.
Results: Of the 24 studies included, 6 were deemed to be of high methodologic quality. Among high quality studies, some reported the measurement error associated with performing repeated measurements of the same image (intraimage analysis), whereas others reported the reliability of obtaining and measuring unique RUSI images (interimage analysis). Intraimage measurements demonstrated good intrarater and interrater reliability (ICC: >0.93). Interimage measurements demonstrated good reliability between raters (ICC: >0.90). Interimage, intrarater correlation coefficients were more variable with ICC values ranging from 0.62 to 0.97.
Conclusion: The methodologic quality of research investigating the reliability of RUSI to measure the abdominal and lumbar trunk muscles needs to be improved. The majority of results of high quality studies indicate that RUSI has good levels of rater reliability. Improved reliability was observed among studies examining muscle thickness, and when using mean measurement values obtained by more experienced examiners.