Projects

Cobb Angle Measurement of Scoliosis Using Computer Measurement of Digitally Acquired Radiographs- Intraobserver and Interobserver Variability

Groups and Associations S Srinivasalu, Hitesh N Modi, Satyen SMehta, Seung-Woo Suh, Ting Chen, Temuujin Murun
Asian Spine Journal 2008

We evaluated computer assisted digital measurement of radiographic parameters in patients with idiopathic
scoliosis.
Purpose: To assess the reliability of digital measurements.
Overview of Literatures: Various authors analyzed scoliotic deformities by conventional radiographs, but very few studies  have addressed the reliability of digital radiographic measurement using computer software.
Methods: Three independent, blinded observers measured 318 whole spine pre-operative antero-posterior radiograms of children with varying degrees of idiopathic scoliosis. Only one curve per radiograph was measured. Each observer measured the Cobb angle three times with a 1-week gap between each measurement. The computer system, picture archiving and communication system (PACS, PiViewSTAR version 5) was used in all cases. The end vertebrae were pre-selected to avoid this as a potential source of error. The results were statistically analyzed for intraobserver and interobserver reliability and
variability.
Results: The 95% confidence intervals for intraobserver and interobserver variability were ±1.30 and ±1.260, respectively. There was better reliability in larger curves.
Conclusions: Measurement using a digitized system may help to minimize measurement discrepancies by eliminating an
intrinsic cause of error.
Key Words: Scoliosis, Digital imaging, Cobb angle, Intraobserver and interobserver variability

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