Multi-cycle dynamic CT imaging

Patent metadata

Field	Value
Publication number	US-9795355-B2
Application number	US-201615095044-A
Country	US
Kind code	B2
Filing date	Apr 9, 2016
Priority date	Apr 9, 2015
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

A dynamic CT imaging method is provided. With the method, projection measurement data for a region of an examination object to be imaged is captured, with simultaneous correlated capture of the respiratory movement of the examination object. A phase of the respiratory movement, for which image data is to be reconstructed, is selected. Phase projection measurement data assigned to the selected phase is also determined. Transition regions of partial images of the region to be imaged between successive respiratory cycles are then reconstructed on a trial basis based on a part of the phase projection measurement data, and a standard reconstruction is performed using parts of the phase projection measurement data for each of the successive respiratory cycles assigned to an optimum reconstruction.

First claim

The invention claimed is:

1. A dynamic CT imaging method comprising:
capturing projection measurement data for a region of an examination object to be imaged, with simultaneous correlated capture of respiratory movement of the examination object;
selecting a phase of the respiratory movement, for which image data is to be reconstructed;
determining phase projection measurement data assigned to the selected phase;
multiple reconstructing transition regions of subregions of the region to be imaged between successive respiratory cycles of the respiratory movement based on candidate projection measurement data sets that are part of the phase projection measurement data;
determining the candidate projection measurement data sets, which correspond to an optimum reconstruction, as target projection measurement data; and
performing a standard reconstruction using the target projection measurement data for each of the successive respiratory cycles.

2. The method of claim 1 , wherein the determining of the phase projection measurement data assigned to the selected phase comprises:
determining at least one start projection index interval assigned to the assigned phase projection measurement data;
determining a plurality of different candidate start projection indices for each start projection index interval; and
performing the reconstruction of transition regions between successive respiratory cycles based on a part of the phase projection measurement data, the multiple reconstruction starting with the plurality of determined different candidate start projection indices.

3. The method of claim 2 , further comprising determining, for optimum reconstruction, optimum start projection indices, the optimum start projection indices including the plurality of different candidate start projection indices, for which the reconstructed transition regions between successive respiratory cycles match one another best, calculating a criterion for how closely reconstructed transition regions between successive respiratory cycles match one another in each instance as a displacement value of an artifact metric, or a combination thereof.

4. The method of claim 3 , wherein the respective candidate start projection indices, for which the displacement value of the artifact metric is a minimum, are determined as the optimum start projection indices.

5. The method of claim 2 , wherein the standard reconstruction is performed using the determined optimum start projection indices for a plurality of different phases.

6. The method of claim 1 , wherein selecting the phase comprises determining corresponding phase time points.

7. The method of claim 2 , further comprising determining start projection indices that are assigned to a plurality of successive respiratory movement cycles and correspond to selected phase time points with the aid of a binning method.

8. The method of claim 7 , further comprising determining each of the at least one start projection index interval as an interval around the determined start projection indices.

9. The method of claim 1 , wherein the multiple reconstructing of transition regions between successive respiratory cycles is performed with interpolation-free assignment to the respective respiratory cycle.

10. The method of claim 1 , wherein the multiple reconstructing of transition regions between successive respiratory cycles is performed sequentially for each of the successive respiratory cycles, starting with a first respiratory cycle that is part of the reconstruction, up to a last respiratory cycle.

11. The method of claim 1 , wherein freely selectable parameters are adapted in a phase-specific manner with the aid of the simultaneous correlated capture of the respiratory movement of the examination object.

12. The method of claim 1 , further comprising:
determining a region in which artifacts are to be reduced based on a previously performed respiration-correlated standard image data reconstruction; and
for the determined region in which artifacts are to be reduced:
capturing projection measurement data with simultaneous correlated capture of respiratory movement of the examination object;
selecting a phase of the respiratory movement, for which image data is to be reconstructed;
determining phase projection measurement data assigned to the selected phase;
multiple reconstructing transition regions of subregions between successive respiratory cycles of the respiratory movement based on candidate projection measurement data sets that are part of the phase projection measurement data;
determining the candidate projection measurement data sets, which correspond to an optimum reconstruction, as target projection measurement data; and
performing a standard reconstruction using the target projection measurement data for each of the successive respiratory cycles.

13. An image data reconstruction device comprising:
an input interface configured to capture projection measurement data for a region of an examination object to be imaged, with simultaneous correlated capture of respiratory movement of the examination object;
a processor configured to:
capture selection information relating to a selected phase of the respiratory movement, for which image data is to be reconstructed;
determine the projection measurement data assigned to the selected phase;
multiple reconstruct of transition regions of subregions of the region to be imaged between successive respiratory cycles based on candidate projection measurement data sets of a part of the phase projection measurement data;
determine the candidate projection measurement data sets, which correspond to an optimum reconstruction, as target projection measurement data; and
perform a standard reconstruction using the target projection measurement data for each of the successive respiratory cycles.

14. A computed tomography system comprising:
a control system comprising:
an image data reconstruction device comprising:
an input interface configured to capture projection measurement data for a region of an examination object to be imaged, with simultaneous correlated capture of respiratory movement of the examination object;
a processor configured to:
capture selection information relating to a selected phase of the respiratory movement, for which image data is to be reconstructed;
determine the projection measurement data assigned to the selected phase;
multiple reconstruct of transition regions of subregions of the region to be imaged between successive respiratory cycles based on candidate projection measurement data sets of a part of the phase projection measurement data;
determine the candidate projection measurement data sets, which correspond to an optimum reconstruction, as target projection measurement data; and
perform a standard reconstruction using the target projection measurement data for each of the successive respiratory cycles.

15. In a non-transitory computer-readable storage medium storing instructions executable by a computer for dynamic CT imaging, the instructions comprising:
capturing projection measurement data for a region of an examination object to be imaged, with simultaneous correlated capture of respiratory movement of the examination object;
selecting a phase of the respiratory movement, for which image data is to be reconstructed;
determining phase projection measurement data assigned to the selected phase;
multiple reconstructing transition regions of subregions of the region to be imaged between successive respiratory cycles of the respiratory movement based on candidate projection measurement data sets t

Assignees

• Hofmann Christian
• Siemens Ag

Inventors

• Hofmann Christian

Classifications

• G06T12/10

  Image preprocessing, e.g. calibration, positioning of sources or scatter correction · CPC title

• A61B6/541

  involving acquisition triggered by a physiological signal · CPC title

• A61B6/032

  Transmission computed tomography [CT] · CPC title

• G06T11/00

  Two-dimensional [2D] image generation · CPC title

• A61B6/03

  Computed tomography [CT] · CPC title