Processing device for obtaining gap filler sinogram information, computer tomograph, method and computer program

Patent metadata

Field	Value
Publication number	US-12423886-B2
Application number	US-202217691913-A
Country	US
Kind code	B2
Filing date	Mar 10, 2022
Priority date	Mar 12, 2021
Publication date	Sep 23, 2025
Grant date	Sep 23, 2025

Abstract

A processing device for obtaining gap-filler sinogram information is adapted to obtain first sinogram information associated with a first spectral parameter, and second sinogram information associated with a second spectral parameter, and is adapted to obtain the gap-filler sinogram information which is associated with the second spectral parameter and which fills the one gap in the second sinogram information, on the basis of the first sinogram information and the second sinogram information. A computer program, a method, and a computer implementation are also described.

First claim

The invention claimed is:

1. An apparatus for use in dual-energy computer tomography (CT), comprising:
a processing device, operable as an integral part of a dual-energy computer tomograph or in data communication with a dual-energy computer tomograph, for generating gap-filler sinogram information for reconstruction of sinograms having gaps,
a radiator and detector adapted to perform a projection through an object to be examined,
the processing device being adapted to acquire first sinogram information associated with a first spectral parameter based on projections recorded by the detector, and
to acquire second sinogram information associated with a second spectral parameter based on projections recorded by the detector,
wherein the processing device being adapted to generate the second sinogram information with fewer detector pixels than the first sinogram information in order to generate a CT image such that the second sinogram information contains less information than the first sinogram information, and
based on the first sinogram information and the second sinogram information, the processing device generating gap-filler sinogram information which is associated with the second spectral parameter to fill the one gap in the second sinogram information on the basis of the first sinogram information and the second sinogram information, wherein a gap of second sinogram information is filled with the information already contained in the obtained first sinogram information;
said processing device using said gap-filler sinogram information to compensate for defective pixels, wherein dual-energy CT data sets are generated with shorter additional measuring time and wherein resolution is enhanced at the location of the gap by filling the identified gap in the second sinogram information using the gap-filler sinogram information;
wherein spatial sinogram information neighbors comprise sinogram information in a neighborhood of
(2 p+ 1)×(2 q+ 1)  (i)

sinogram information neighbors of the first sinogram information comprise sinogram information comprising coordinates
([ x+/−p, y+/−q, α])  (ii),

and sinogram information neighbors of the second sinogram information comprise sinogram information with coordinates
([ x+/−p,y+/−q,α−r ]) and ([ x+/−p,y+/−q,α+r ])   (iii),

where in (i), (ii) and (iii), p is a pixel-wise deviation in a first direction x that is perpendicular to a projection angle a, q is a pixel-wise deviation in a second direction y that is parallel to an axis of rotation of the projection angle α and to the first direction x, and r is an angular deviation.

2. The processing device as claimed in claim 1 ,
wherein the gap corresponds to one or more pixels.

3. The processing device as claimed in claim 1 ,
the processing device being adapted to acquire the gap-filler sinogram information to acquire a resolution-enhanced version of the second sinogram information.

4. The processing device as claimed in claim 1 ,
wherein the first sinogram information exhibits a first angular resolution,
wherein the second sinogram information comprises a second angular resolution that is smaller than the first angular resolution, and
the processing device being adapted to acquire the gap-filler sinogram information for an angular value that is between two angular values of the second sinogram information.

5. The processing device as claimed in claim 1 ,
wherein the second sinogram information for acquiring the gap-filler sinogram information is sinogram information comprising sinogram information neighbors, of the gap, of the second sinogram information.

6. The processing device as claimed in claim 1 ,
the processing device being adapted to acquire the gap-filler sinogram information on the basis of one or more sinogram values of the second sinogram information that are adjacent to the gap and, additionally, one or more sinogram values of the first sinogram information that are adjacent to the gap and/or one or more sinogram values of the first sinogram information that are associated with the gap.

7. The processing device as claimed in claim 1 ,
wherein the first sinogram information for acquiring the gap-filler sinogram information is sinogram information comprising sinogram information neighbors, of the gap, of the first sinogram information, and first sinogram information of the gap.

8. The processing device as claimed in claim 1 ,
the processing device being adapted to acquire the first and second sinogram information simultaneously with one scan or sequentially with two scans.

9. The processing device as claimed in claim 1 ,
wherein the first sinogram information comprises a plurality of transmission image lines or transmission images that are associated with different angles, and
wherein the second sinogram information comprises a plurality of transmission image lines or transmission images associated with different angles, and
wherein the first sinogram information and the second sinogram information are associated with different fluoroscopic radiation energies of a multi-energy computer tomography.

10. The processing device as claimed in claim 1 ,
the processing device being adapted to acquire the gap-filler sinogram information while using a neural network.

11. The processing device as claimed in claim 1 ,
wherein the neural network comprises at least one of Convolutional Neural Network, Generative Adversarial Network, and U-Net.

12. A computer tomograph for use in dual-energy computer tomography (CT), comprising:
at least one processing device, operable as an integral part of a dual-energy computer tomograph or in data communication with a dual-energy computer tomograph, for generating gap-filler sinogram information for reconstruction of sinograms having gaps, a radiator and detector adapted to perform a projection through an object to be examined, the processing device being adapted to acquire first sinogram information associated with a first spectral parameter based on projections recorded by the detector, and to acquire second sinogram information associated with a second spectral parameter based on projections recorded by the detector, wherein the processing device being adapted to generate the second sinogram information with fewer detector pixels than the first sinogram information in order to generate a CT image such that the second sinogram information contains less information than the first sinogram information, and based on the first sinogram information and the second sinogram information, the processing device generating gap-filler sinogram information which is associated with the second spectral parameter to
fill the one gap in the second sinogram information on the basis of the first sinogram information and the second sinogram information, wherein a gap of second sinogram information is filled with the information already contained in the obtained first sinogram information;
said processing device using said gap-filler sinogram information to compensate for defective pixels, wherein dual-energy CT data sets are generated with shorter additional measuring time and wherein resolution is enhanced at the location of the gap by filling the identified gap in the second sinogram information using the gap-filler sinogram information;
wherein spatial sinogram information neighbors comprise sinogram information in a neighborhood of
(2 p+ 1)×(2 q+ 1)  (i)

sinogram information neighbors of the first sinogram information comprise sinogram information comprising coordinates
([ x+/−p,y+/−q ,α])  (ii),

and sinogram information neighbors of the second sinogram information comprise sinogram information wi

Assignees

• Fraunhofer Ges Forschung

Inventors

• Firsching Markus
• Ennen Alexander
• Speier Christoph

Classifications

• G06T12/30 Primary

  Image post-processing, e.g. metal artefact correction · CPC title

• G06T12/10 Primary

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

• G06T2211/408

  Dual energy · CPC title

• G06T2207/30004

  Biomedical image processing · CPC title

• G06T2207/20084

  Artificial neural networks [ANN] · CPC title