Calculating a four dimensional DSA dataset with variable spatial resolution

A digital subtraction angiography (DSA) calculation unit for calculating a four-dimensional DSA dataset, comprising:

• a communication interface for receiving x-ray datasets relating to an examination volume, wherein each of the x-ray datasets having has a two-dimensional x-ray projection of an examination volume in relation to a direction of projection and a recording time of the two-dimensional x-ray projection;
• and
• a processor configured to determine a first three-dimensional DSA dataset of a first reconstruction volume on a basis of the x-ray datasets, wherein a first reconstruction volume is a part of the examination volume or is identical with the examination volume, said processor being further configured for determining a second three-dimensional DSA dataset of a second reconstruction volume on a basis of the x-ray datasets, wherein the first and second three-dimensional DSA datasets have mutually different spatial resolutions and wherein the second reconstruction volume is a part of the first reconstruction volume, said processor being further embodied for segmenting the second three-dimensional DSA dataset, for normalizing of the x-ray datasets on a basis of the first three-dimensional DSA dataset, and calculating the four-dimensional DSA dataset by back projection of normalized x-ray datasets onto a segmented second three-dimensional DSA dataset, wherein the four-dimensional DSA dataset contains a plurality of third three-dimensional DSA datasets as well as associated time information.

A non-transitory computer-readable storage medium comprising executable instructions to be read and executed by a digital subtraction angiography (DSA) calculation unit which comprises the steps of:

• receiving x-ray datasets relating to an examination volume by means of a communication interface, each of the x-ray datasets containing a two-dimensional x-ray projection of the examination volume in relation to a direction of projection and a recording time of the two-dimensional x-ray projection;
• determining a first three-dimensional DSA dataset of a first reconstruction volume on a basis of the x-ray datasets by means of a processor, wherein the first reconstruction volume is a part of the examination volume or is identical to the examination volume;
• determining a second three-dimensional DSA dataset of a second reconstruction volume on a basis of the x-ray datasets by the calculation apparatus processor, wherein the second reconstruction volume is a part of the first reconstruction volume;
• wherein the first and second three-dimensional DSA datasets have mutually different spatial resolutions;
• segmenting the second three-dimensional DSA dataset by means of the processor;
• normalizing the x-ray datasets on a basis of the first three-dimensional DSA dataset by means of the processor;
• and
• calculating a four-dimensional DSA dataset by back projection of normalized x-ray datasets onto a segmented second three-dimensional DSA dataset by means of the processor, the four-dimensional DSA dataset having a plurality of third three-dimensional DSA datasets as well as associated time information.