Calculating an image matrix size

Patent metadata

Field	Value
Publication number	US-11080853-B2
Application number	US-202016775362-A
Country	US
Kind code	B2
Filing date	Jan 29, 2020
Priority date	Feb 8, 2019
Publication date	Aug 3, 2021
Grant date	Aug 3, 2021

Abstract

An embodiment of the invention relates to a method for calculating an image matrix size N for reconstructing image data of an examination subject from projection data. The method includes acquiring projection data obtained during a relative rotational movement between a radiation source of a computed tomography system and the examination subject; calculating the image matrix size N as a function of an extent of an axial field of view of the computed tomography system and a sharpness value in the image data to be reconstructed; and making the calculated image matrix size available to a reconstruction unit to reconstruct the image data from the projection data acquired.

First claim

What is claimed is:

1. A method for calculating an image matrix size N for reconstructing image data of an examination subject from projection data, the method comprising:
acquiring projection data obtained during a relative rotational movement between a radiation source of a computed tomography system and the examination subject;
calculating the image matrix size N as a function of an extent of an axial field of view of the computed tomography system and a sharpness value in the image data to be reconstructed; and
making the calculated image matrix size available to a reconstruction unit to reconstruct the image data from the projection data acquired, wherein the image matrix size N is calculated during the calculating, taking into account an available storage capacity.

2. The method of claim 1 , wherein the image matrix size N is calculated as a function of a minimum increment ΔN for the image matrix size.

3. The method of claim 1 , wherein the image matrix size N is calculated taking into account at least one of
at least one parameter of a reconstruction algorithm and
a reconstruction kernel of the reconstruction algorithm.

4. The method of claim 1 , wherein the image matrix size N is calculated taking into account a minimum image quality to be achieved.

5. The method of claim 1 , wherein the image matrix size N is calculated taking into account at least one of
a medical issue underlying projection data acquisition,
at least one parameter of a measurement protocol used for the projection data acquisition and
a parameter representing an imaged body region.

6. The method of claim 1 , wherein the image matrix size N is calculated according to

N
=

Δ
⁢
N
*

⌈

2
*
a
*

F

a
⁢
x

*

ρ
c

Δ
⁢
N

⌉

,

wherein N—is the image matrix size calculated,
ΔN—is a minimum increment for the image matrix size,
F ax —is the axial field of view,
ρ c —is the sharpness value, and
a—is a proportionality constant.

7. The method of claim 1 , wherein the image matrix size is calculated according to

N
=

min
⁢

{

N
max

,

max
⁡

(

N
min

,

⁢

Δ
⁢
N
*

⌈

2
*

F

a
⁢
x

*

ρ
c

*
f

Δ
⁢
N

+
c

⌉

)

}

,

where N—is the image matrix size calculated,
ΔN—is a minimum increment for the image matrix size,
N max is a maximum permitted image matrix size,
N min —is a minimum permitted image matrix size,
F ax —is the axial field of view,
ρ c —is the sharpness value,
f—is a free scaling factor, and
c—is a free offset parameter.

8. The method of claim 1 , wherein the sharpness value is calculated taking into account a functional of a modulation transfer function of the computed tomography system.

9. A device to calculate an image matrix size N for reconstructing image data of an examination subject from projection data, the device comprising:
at least one processor embodied to
acquire projection data, recorded during a relative rotational movement between a radiation source of a computed tomography system and the examination subject; and
calculate the image matrix size N as a function of an extent of an axial field of view of the computed tomography system and a sharpness value in the image data to be reconstructed, wherein the image matrix size N is calculated, taking into account an available storage capacity.

10. The device of claim 9 , further comprising:
at least one additional processor embodied to register the image matrix size N calculated and to use the image matrix size N calculated to reconstruct the image data from the projection data.

11. A computed tomography system for calculating an image matrix size N for reconstructing image data of an examination subject from projection data, comprising:
a device, including at least one processor, embodied to
acquire projection data recorded during a relative rotational movement between a radiation source of a computed tomography system and the examination subject, and
calculate the image matrix size N as a function of an extent of an axia

Assignees

• Siemens Healthcare Gmbh

Inventors

• Feuerlein Ute
• Petersilka Martin
• Raupach Rainer
• Sunnegaardh Johan

Classifications

• G06T12/20 Primary

  Inverse problem, i.e. transformations from projection space into object space · CPC title

• G06T12/30

  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

• G06T2210/41

  Medical · CPC title

• G06T2211/421

  Filtered back projection [FBP] · CPC title