Quantitative analysis of structural abnormality of the vestibular system in progressive and non-progressive adolescent idiopathic scoliosis (AIS) using MRI techniques

Materials and methods Twenty-five non-progressive (NP-AIS) and 17 progressive (P-AIS) right-thoracic AIS patients and 20 age-matched normal controls (NC) were recruited in this research. High resolution T2-weighted images of their VS were obtained. The anatomical variances of the semicircular canals were described using approximated best-fit circle. Lengths and angles of the lines joining centers of the bestfit circles, radius of the circles and the rotational angles around the three major orthogonal axes were used for shape description of the VS. The measurements of the AIS groups were compared with those of the normal control group using one-way ANOVA. Results Statistically significant differences were observed in the shape analysis of the left-side VS between AIS and normal controls. Firstly, the distance between the centers of the lateral and superior canals was P-AIS<NP-AIS<NC (p=0.0370). Secondly, the angle between the center-joining lines at the posterior canal was P-AIS<NP-AIS<NC (p=0.0018). In the right-side VS, no significant group difference was detected.