Inter-tester and intra-tester reliability of ultrasound imaging measurements of abdominal muscles in adolescents with and without idiopathic scoliosis: a case-controlled study.

The present study established inter-tester and intra-tester reliabilities of ultrasound imaging and diagnostically differentiated muscle imbalances in lateral abdominal muscle sizes between normal adolescents and adolescents with idiopathic scoliosis (AIS). Fifteen adolescents with AIS were age- and gender-matched with 15 normal adolescents. There was no significant difference between bilateral abdominal muscles in normal adolescents, but there was a significant difference between bilateral abdominal muscles in adolescents with AIS (P<0.05). Overall, inter-tester and intra-tester reliabilities in normal and AIS adolescents ranged from 0.801-0.984. This novel study shows that using ultrasound imaging to measure lateral abdominal muscle thickness is: (1) highly reliable between and within the testers; and (2) capable of distinguishing between subjects with and without pathological muscle morphology due to AIS.