Calculating an image matrix size

Patent metadata

Field	Value
Publication number	US-2020258221-A1
Application number	US-202016775362-A
Country	US
Kind code	A1
Filing date	Jan 29, 2020
Priority date	Feb 8, 2019
Publication date	Aug 13, 2020
Grant date	—

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.

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 taking into account an available storage capacity.

7 . 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.

8 . 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.

9 . 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.

10 . A computing unit to calculate an image matrix size N for reconstructing image data of an examination subject from projection data, wherein the computing unit is 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.

11 . The computing unit of claim 10 , further comprising:
a reconstruction unit, 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.

12 . A computed tomography system for calculating an image matrix size N for reconstructing image data of an examination subject from projection data, comprising:
a computing unit 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

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

• G06T2211/421

  Filtered back projection [FBP] · CPC title

• G06T2211/424

  Iterative · CPC title