Comparison of manual and computerized measurements of sagittal vertebral inclination in MR images

Abstract

In this study, sagittal vertebral inclination (SVI) was systematically measured by three observers for 28 vertebrae (T4-L5) from one normal and one scoliotic magnetic resonance (MR) spine image using six manual and two computerized measurements. Manual measurements were performed by superior and inferior tangents, anterior and posterior tangents, and mid-endplate and mid-wall lines. Computerized measurements were performed by automatically evaluating the symmetry of vertebral anatomy in sagittal cross-sections and volumetric images. The mid-wall lines were the manual measurements with the lowest intra- and inter-observer variability (1.4◦and 1.9◦standard deviation, SD). The strongest inter-method agreement was found between themid-wall lines and posterior tangents (2.0◦SD). Computerized measurements did not yield intra- and inter-observer variability (2.8◦and 3.8◦SD) as low as the mid-wall lines, but were still comparable to the intra- and inter-observer variability of the superior (2.6◦and 3.7◦SD) and inferior (3.2◦and 4.5◦SD) tangents.