Method for reconstructing a 3D presentation

A medical system for reconstructing a 3D presentation of a hollow organ of a patient, comprising:

• a catheter that records a plurality of two-dimensional catheter images of the hollow organ while withdrawing the catheter from a start position in the hollow organ;
• a catheter control unit that assigns a withdrawal length to each two-dimensional catheter image;
• an x-ray device that records at least two fluoroscopy images at two different angles showing the hollow organ and a tip of the catheter;
• and
• a processing unit that:
• determines the start position of the catheter from the fluoroscopy images in a three-dimensional model of the hollow organ,
• determines a most probable withdrawal path of the catheter based on the three-dimensional model of the hollow organ,
• determines a deviation of a position of the catheter from a central path running through a middle of the hollow organ and an orientation of the catheter for each two-dimensional catheter image based on the most probable withdrawal path and the withdrawal length, and
• reconstructs the 3D presentation of the hollow organ based on the two-dimensional catheter images as well as the deviation of the position of the catheter from the central path and the orientation of the catheter,
• wherein the deviation of the position of the catheter from the central path is determined from the catheter images during the reconstruction,
• wherein a fixed threshold for a difference of the deviation from the central path determined from the most probable withdrawal path and from the catheter images is predetermined,
• wherein if the difference exceeds the fixed threshold, the most probable withdrawal path is recalculated from a position at which the threshold is exceeded, and
• wherein the recalculated most probable withdrawal path is used for reconstructing the 3D presentation of the hollow organ.