An evaluation of the inter-rater and intra-rater reliability in volume measurements with a 3D ultrasound apparatus of the musculus multifidus in healthy subjects

Abstract

Background: 3D ultrasound is proven to be a time saving, cost-effective alternative to magnetic resonance imaging (MRI) when measuring muscle volumes of certain muscles. No research has yet been done to evaluate the reliability of a 3D ultrasound apparatus to investigate muscle volume of deeply located trunk muscles, such as the multifidus (MF) muscle, by inexperienced examiners. Objectives: The purpose of this Master’s thesis is to evaluate the inter-rater and intra-rater reliability of a 3D freehand ultrasound apparatus to measure the muscle volume of the MF. This study investigates the reliability of inexperienced ultrasonographers in particular. Participants: Ten women and ten men under the age of 60 years were recruited through local advertisement and were screened for eligibility. Measurements: Measurements of the MF were conducted in a standardized manner by both examiners to calculate intra-rater reliability, and again, by the first examiner to calculate the inter-rater reliability. Subsequently, the obtained ultrasound slices were examined separately by each examiner. Results: The inter-rater reliability showed poor to good reliability (ICC: 0.718; 95% CI: 0.251-0.894). Intra-rater reliability scored higher with moderate to excellent reliability (ICC: 0.863; 95% CI: 0.670-0.946). Two participants were excluded due to measurement errors. Keywords: 3D ultrasound, reliability, inter-rater, intra-rater, inexperienced, multifidus muscle, ultrasonographers, imaging