Reliability Of Ultrasound Panoramic Imaging Of Muscle Size For The Transversus Abdominis

Abstract

PURPOSE: The transversus abdominis (TrA) is a key muscle in core stability. Measurements of its morphology might shed some light on structure, function and pathology of core muscles. A new ultrasound technique, panoramic imaging, could be used to visualize the whole length of the muscle in one image. The purpose of this study is to assess the degree to which this technique produces stable and consistent results. METHODS: 6 female participants; age(years)= 21.3 ± 1.6; height(cm)= 167.5 ± 5.1; weight(kg) = 65.5 ± 11.0 volunteered for this study. With the participants in side-lying position, muscle length, muscle area and thickness were scanned using GE Logic S8 (6-15 MHz probe). The right and left TrA muscles were imaged twice on each subject at spinal levels L1, L3 and L5 and later measured by two separate investigators. Test-retest reliability was calculated using interclass correlation coefficient (ICC) (random subjects and fixed raters) along with the Standard Error of Measurement (SEM). RESULTS: Our panoramic measures showed excellent intertester reliability for length, area and thickness measurements (ICC=0.981, 0.982, 0.985, respectively). In addition, the SEM for length, area and thickness were SEM= 0.178, 0.078, 0.046, respectively. CONCLUSIONS: Our method of assessing TrA morphology showed excellent reliability in the three dimensions measured and had low error rates that were equal to or better than those associated with other muscles previously measured. Panoramic imaging seems to be a reliable technique that could be used to visualize the whole TrA muscle in one image. Comparison to MRI images would further help establish its validity.