A Reliable Semi-automatic Program to Measure the Vertebral Rotation Using the Center of Lamina for Adolescent Idiopathic Scoliosis

Abstract

Adolescent idiopathic scoliosis (AIS) is a three-dimensional (3D) spinal deformity. Radiography is the standard method to diagnose AIS, but the 2D image cannot reveal the true nature of scoliosis. It also exposes patients to harmful ionizing radiation. Ultrasound (US) imaging has been reported as a non-radiation method to acquire 3D information of the spine. Vertebral rotation (VR) that can be assessed from US image is an important parameter to predict curve progression and to evaluate treatment outcomes. To improve the image quality and reduce human errors, a semi-automatic program was developed to measure the VR. The purpose of this study was to determine the intra-observer reliability and the accuracy of the measurements using the developed program. Three cadaver vertebrae, T7, L1, and L3, were scanned with 39 rotation configurations from -30° to 30° with 5° increment. The US images were randomly arranged to reduce memory bias. One observer performed the semi-automatic VR measurements twice with one-week interval. The semi-automatic VR measurements showed high intra-observer reliability (intraclass correlation coefficient (ICC): 0.999, mean absolute difference with standard deviation (MAD±SD): 0.2°±0.3°) and agreed well with the experimental setup (ICC: 0.956, MAD±SD: 2.5°±1.5°). The results demonstrated the developed program was an accurate and reliable measurement tool to assess the VR for in-vitro study.