Computer-implemented method for ascertaining an item of torsion information of a bone, x-ray facility, computer program and electronically readable data carrier

Abstract

Systems and methods for ascertaining an item of torsion information of a bone of a patient, wherein an X-ray facility with adjustable projection geometry of a recording arrangement described by projection parameters is used. A first X-ray image is recorded of an end region of the bone in a first projection geometry in which a torsion direction defined relative to at least one torsion landmark and used for ascertaining a roll angle lies in a first computing plane, which is formed by the focal point of the X-ray source and a reference direction which may be determined in the first X-ray image by at least one reference landmark. A second X-ray image is recorded of the end region of the bone in a second projection geometry with a direction of projection deviating from the direction of projection of the first projection geometry, and forming a second computing plane from the reference direction which may be determined in the second X-ray image likewise by the at least one reference landmark, and the focal point. The three-dimensional course of the reference direction and the torsion direction is determined from the computing planes and the roll angle as the rotation of the torsion direction about the reference direction with respect to a comparison specification. The item of torsion information is ascertained from the roll angle.