Method and magnetic resonance apparatus for determination of magnetic resonance angiography images using time-of-flight angiography

Patent metadata

Field	Value
Publication number	US-2016166172-A1
Application number	US-201514967840-A
Country	US
Kind code	A1
Filing date	Dec 14, 2015
Priority date	Dec 15, 2014
Publication date	Jun 16, 2016
Grant date	—

Abstract

In a method and apparatus, magnetic resonance angiography images of an examination volume of a patient are obtained using time-of-flight angiography in a magnetic resonance scanner. By continuous recording, a number of two-dimensional slice images covering the examination volume along an axial direction are acquired in a slice-by-slice layer-wise, such as with overlapping. The slice images are divided into groups of, in each case, a predetermined number of consecutive slice images in the axial direction. A maximum intensity projection image is determined for each group, and the angiography images are determined as the maximum intensity projection images and/or dependent on the maximum intensity projection images.

First claim

I claim as my invention:

1 . A method for generating a magnetic resonance (MR) angiography image, comprising:
operating an MR scanner, while a patient is situated therein, to obtain a plurality of successive two-dimensional slice images that cover an examination volume of the patient along an axial direction slice-by-slice, using a time-of-flight angiography MR data acquisition sequence; providing said plurality of slice images to a processor and, in said processor, dividing said plurality of slice images into respective groups with each group comprising a predetermined number of consecutive slice images along said axial direction; in said processor, determining a maximum intensity projection image for each group; and in said processor, determining diagnostic angiography images as the respective maximum intensity projection images for the respective groups, or dependent on the maximum intensity projection images for each group, and making said diagnostic angiography images available in electronic form from said processor as respective data files.

2 . A method as claimed in claim 1 comprising operating said MR scanner to acquire said plurality of two-dimensional slice images so that at least some successive slice images overlap each other.

3 . A method as claimed in claim 1 comprising, in said processor, using a correlation measure among all slice images in each group to determine said maximum intensity projection image.

4 . A method as claimed in claim 2 comprising using the slice image with the highest correlation measure in each group as the diagnostic angiography image.

5 . A method as claimed in claim 2 comprising using all slice images in each group that have a correlation measure that exceeds a predetermined threshold value as a diagnostic angiography image.

6 . A method as claimed in claim 2 comprising assigning a recording position to a slice image in each group having a highest correlation measure to the maximum intensity projection image, and also giving said angiography image said slice position.

7 . A method as claimed in claim 1 comprising determining said predetermined number as a function of an image recording rate of said plurality of two-dimensional slice images and as a function a duration of the cardiac cycle of the patient.

8 . A method as claimed in claim 7 comprising determining said predetermined number as a product of said duration and said image recording rate.

9 . A method as claimed in claim 7 comprising using a predetermined maximum duration of said cardiac cycle as said duration.

10 . A method as claimed in claim 9 comprising setting said predetermined maximum duration to be in a range between 800 and 1100 ms.

11 . A method as claimed in claim 9 comprising setting said predetermined maximum duration to be 1000 ms.

12 . A method as claimed in claim 7 comprising using a patient-specific duration of said cardiac cycle as said duration.

13 . A method as claimed in claim 12 comprising determining said patient-specific duration of said cardiac cycle by evaluating said plurality of slice images in said processor.

14 . A method as claimed in claim 1 comprising operating said MR scanner to acquire said plurality of two-dimensional slice images with respectively constant slice positions that are defined by a continuously moving patient table, on which said patient is situated, that moves through said MR scanner.

15 . A method as claimed in claim 14 comprising selecting a movement speed of said patient table dependent on a slice thickness of one slice respectively represented by one of said plurality of two-dimensional slice images.

16 . A magnetic resonance (MR) apparatus comprising:
an MR scanner; a computer configured to operate said MR scanner, while a patient is situated therein, to obtain a plurality of successive two-dimensional slice images that cover an examination volume of the patient along an axial direction slice-by-slice, using a time-of-flight angiography MR data acquisition sequence; said computer being configured to divide said plurality of slice images into respective groups with each group comprising a predetermined number of consecutive slice images along said axial direction; said computer being configured to determine a maximum intensity projection image for each group; and said computer being configured to determine diagnostic angiography images as the respective maximum intensity projection images for the respective groups, or dependent on the maximum intensity projection images for each group, and to make said diagnostic angiography images available in electronic form from said computer as respective data files.

17 . A non-transitory, computer-readable data storage medium encoded with programming instructions, said storage medium being loaded into a control computer of a magnetic resonance (MR) apparatus that comprises an MR scanner, and said programming instructions causing said control computer to:
operate said MR scanner, while a patient is situated therein, to obtain a plurality of successive two-dimensional slice images that cover an examination volume of the patient along an axial direction slice-by-slice, using a time-of-flight angiography MR data acquisition sequence; divide said plurality of slice images into respective groups with each group comprising a predetermined number of consecutive slice images along said axial direction; determine a maximum intensity projection image for each group; and determine diagnostic angiography images as the respective maximum intensity projection images for the respective groups, or dependent on the maximum intensity projection images for each group, and make said diagnostic angiography images available in electronic form from said processor as respective data files.

Assignees

• Siemens Ag

Inventors

• Zenge Michael

Classifications

• G06T12/30

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

• A61B5/704

  Tables · CPC title

• G01R33/56383

  involving motion of the sample as a whole, e.g. multistation MR or MR with continuous table motion · CPC title

• G01R33/5635

  Angiography, e.g. contrast-enhanced angiography [CE-MRA] or time-of-flight angiography [TOF-MRA] · CPC title

• A61B5/7289

  Retrospective gating, i.e. associating measured signals or images with a physiological event after the actual measurement or image acquisition, e.g. by simultaneously recording an additional physiological signal during the measurement or image acquisition · CPC title