EVALUATION OF CT SCANS AND 3-D REFORMATTED IMAGES FOR QUANTITATIVE ASSESSMENT OF THE HIP

Hip measurements using three-dimensional (3-D) images and computed tom ography (CT) scans were evaluated. The 3-D measurements proved more ac curate than CT measurements of femoral and acetabular anteversion. Add itionally, accurate 3-D measurements (>99%) of the femoral neck-shaft angle were provided. Acetabular anteversion determinations by CT scans were systematically decreased as pelvic flexion increased, whereas ac curacy was >96% with 3-D images. The 3-D software allows image rotatio n in all three reference planes, which minimizes positional errors. A case study is provided to exemplify the shortcomings of conventional i maging techniques and the utility of the quantitative 3-D protocol.