Evaluation of sagittal vertebral rotation in CT images by manual and automated methods

Sagittal vertebral rotation (SVR) was systematically measured for 14 normal and 14 scoliotic vertebrae in images, acquired by computed tomography (CT). Manual measurements were performed by three observers, who identified the anatomical landmarks required to evaluate SVR by six manual methods (superior and inferior tangents, anterior and posterior tangents, mid-endplate and mid-wall lines). Automated measurements were performed by evaluating SVR from the symmetry of vertebral anatomical structures in two-dimensional (2D) sagittal cross-sections and in three-dimensional (3D) images. The low intra- and inter-observer variabilities of the automated method (standard deviation 0.9° and 1.6°) prove that the symmetry-based determination of SVR may yield higher measurement reproducibility and reliability while representing a faster, more feasible and more observer-friendly alternative to manual methods.