title: 3-D repositioning and differential images of volumetric CT measurements.
abstract: In quantitative computed tomography (QCT), time serial measurements are performed to detect a global bone density loss or to identify localized bone density changes. A prerequisite for an unambiguous analysis is the comparison of identical bone volumes. Usually, manual repositioning is too coarse. A mathematical procedure that allows matching two three-dimensional image volumes is presented. The algorithm is based on correlation techniques. The procedure has been optimized and applied to computer-tomographic 3-D images of the human knee. It has been tested with both artificially created and in vivo measured image data. Typical differential images calculated from real bone measurements are presented.
authors.affiliation: Inst. for Biomed. Eng., Federal Inst. of Technol. of Zurich.
authors.forename: B
authors.initials: B
authors.lastname: Munch
authors.forename: P
authors.initials: P
authors.lastname: Ruegsegger