Assessment of the validity of observing three-dimensional images of the spine using polarising, synchronised techniques.

: Three-dimensional imaging is an emerging technique in radiology. It might be used to help view the spine and assist in improving evaluation of scoliosis. These images are currently computer generated and although very effective are actually optical iflusions. Questions remain as to the reliability and validity of these images which are important considerations when treatment regimens are being developed and surgery contemplated. Using a constructed three-diemnsional image of a box, this study assessed the inter- and intra-reliability of viewing a specific point on this box and also the inter-reliability of identifying the coordinates of this same point. There was good reliability for viewing a single point in the X and Z axes which formed the plane of the computer but there was a 10X decrease in reliability along the Y-axis (depth). This pattern was repeated when considering the relationship between observers to identify the actual coordinates of the same point.