Method and device for generating a CT image with a high time resolution

A computed tomography scanner for generating a CT image of an object, comprising:

• at least n=2 recording systems, arranged on a rotating frame and angularly offset by an angle of 180°/n with respect to one another, the at least n=2 recording systems being operable at different X-ray energy spectra to record measurement data of the object at the different X-ray energy spectra during a semi-rotation of the rotating frame with the recording systems;
• and
• a control and computational unit, in which a reconstruction module is formed to generate a CT image the measurement data of the recording systems by:
• respectively reconstructing a preliminary CT image of the object from the measurement data for each of the respective recording systems,
• segmenting the contrast agent-enriched structures in the preliminary CT images in order to respectively obtain a contrast agent image and a soft tissue image,
• subjecting the contrast agent and soft tissue images to a re-projection in order to obtain contrast agent projection data and soft tissue projection data,
• calculating irradiated lengths of the structures and the soft tissue for each projection from the projection data and known mean absorption coefficients of the contrast agent and the soft tissue at the different X-ray energy spectra,
• calculating an artificial measurement data record for an angular range of 180°/n for each recording system on the basis of the calculated irradiated lengths for a common X-ray energy or a common X-ray energy spectrum, with the angular ranges complementing one another to form a semi-rotation, and
• reconstructing the CT image from the artificial measurement data records.