Method for acquiring a magnetic resonance image dataset and generating a motion-corrected image dataset

Patent metadata

Field	Value
Publication number	US-12467994-B2
Application number	US-202318519741-A
Country	US
Kind code	B2
Filing date	Nov 27, 2023
Priority date	Dec 15, 2022
Publication date	Nov 11, 2025
Grant date	Nov 11, 2025

Abstract

A method is provided for acquiring a magnetic resonance image dataset of an object, using an imaging protocol in which several k-space lines are acquired in one echo train, wherein the echo train may include one or several sub echo trains, and wherein the imaging protocol includes a plurality of echo trains. Within the method, a set of additional k-space lines within a central region of k-space is acquired a number of times per echo train, wherein the number is greater than 1, in order to detect movement of the object during the echo train. The sets of additional k-space lines are acquired at pre-determined positions within the echo trains. The disclosure is also directed to a method for generating a motion-corrected magnetic resonance image dataset from the dataset thus acquired, a magnetic resonance imaging apparatus, and a computer program.

First claim

The invention claimed is:

1 . A method for acquiring a magnetic resonance image dataset of an object, the method comprising:
using an imaging protocol in which spatial encoding is performed using phase encoding gradients along at least one spatial dimension, and frequency encoding gradients along another spatial dimension, wherein k-space is sampled during an acquisition in a plurality of k-space lines oriented along a frequency encoding direction; acquiring several k-space lines in one echo train, wherein the imaging protocol comprises a plurality of echo trains; and acquiring at least one set of additional k-space lines within a central region of the k-space a plurality of times per echo train in more than 85% of the plurality of echo trains, wherein the at least one set of additional k-space lines is acquired in addition to k-space lines required under the imaging protocol to acquire the magnetic resonance image dataset, wherein each set of additional k-space lines of the at least one set of additional k-space lines is acquired at a pre-determined position within the plurality of echo trains.

2 . The method of claim 1 , wherein at least one echo train of the plurality of echo trains comprises at least one sub echo train.

3 . The method of claim 1 , further comprising:
acquiring at least one low-resolution scout image of the object.

4 . The method of claim 3 , wherein the at least one low-resolution scout image comprises a plurality of low-resolution scout images,
wherein a number of the plurality of low-resolution scout images is a same number or a smaller number than a number of sets of additional k-space lines acquired per echo train, wherein the plurality of low-resolution scout images is acquired with a contrast corresponding to pre-determined positions of the sets of additional k-space lines within the echo train.

5 . The method of claim 1 , wherein two sets of additional k-space lines are acquired in each echo train or each sub echo train, and
wherein a first set of the two sets of additional k-space lines is acquired in a first half of each echo train or each sub echo train and a second set of the two sets of additional k-space lines is acquired in a second half of each echo train or each sub echo train.

6 . The method of claim 1 , wherein three sets of additional k-space lines are acquired in each echo train or each sub echo train, and
wherein a first set of the three sets of additional k-space lines is acquired in a 1 st third half of each echo train or each sub echo train, a second set of the three sets of additional k-space lines is acquired in a 2 nd third of each echo train or each sub echo train, and a third set of the three sets of additional k-space lines is acquired in a 3 rd third of each echo train or each sub echo train.

7 . The method of claim 1 , wherein the pre-determined position in the k-space of the additional k-space lines in each set of additional k-space lines is constant or is varied slightly for each set of additional k-space lines within ±5% of an extension of the k-space.

8 . The method of claim 1 , wherein 2 to 16 additional k-space lines are acquired in each set of additional k-space lines.

9 . The method of claim 1 , wherein the k-space is sampled in a sampling order in which the one or several phase encoding gradients are changed incrementally from one k-space line to a next k-space line, with an exception of the additional k-space lines.

10 . The method of claim 1 , wherein the imaging protocol uses a parallel imaging technique in which one phase encoding direction or all phase encoding directions are subsampled by a predetermined acceleration factor, and
wherein the magnetic resonance image dataset is acquired using a multi-channel coil array.

11 . A method for generating a motion-corrected magnetic resonance image dataset of an object, the method comprising:
receiving k-space data acquired using an acquisition method, the acquisition method comprising:
using an imaging protocol in which spatial encoding is performed using phase encoding gradients along at least one spatial dimension, and frequency encoding gradients along another spatial dimension, wherein k-space is sampled during an acquisition in a plurality of k-space lines oriented along a frequency encoding direction;
acquiring several k-space lines in one echo train, wherein the imaging protocol comprises a plurality of echo trains; and
acquiring at least one set of additional k-space lines within a central region of the k-space a plurality of times per echo train in more than 85% of the echo trains, wherein the additional k-space lines are acquired in addition to k-space lines required under the imaging protocol to acquire a magnetic resonance image dataset,
wherein each set of additional k-space lines of the at least one set of additional k-space lines is acquired at a pre-determined position within the plurality of echo trains;
receiving at least one low-resolution scout image of the object; estimating motion parameters for each set of additional k-space lines by comparing the respective additional k-space lines with the at least one low-resolution scout image; and estimating the motion-corrected magnetic resonance image dataset by minimizing a data consistency error between the k-space data acquired in the imaging protocol and a forward model described by an encoding matrix, wherein the encoding matrix includes the motion parameters for each set of additional k-space lines, Fourier encoding, and optionally subsampling and/or coil sensitivities of a multi-channel coil array.

12 . The method of claim 11 , wherein the receiving of the at least one low-resolution scout image of the object comprises receiving a plurality of low-resolution scout images of the object, wherein each scout image of the at least one low-resolution scout image has a contrast corresponding to the pre-determined positions of the at least one set of additional k-space lines within the plurality of echo trains,
wherein the minimizing of the data consistency error is executed by:
(1) estimating the motion parameters for each set of additional k-space lines by comparing the respective additional k-space lines with the respective low-resolution scout image corresponding to a same position within the echo train as the set of additional k-space lines; and
(2) estimating the motion-corrected magnetic resonance image dataset using the estimated motion parameters.

13 . The method of claim 12 , further comprising:
interpolating between the motion parameters estimated for each set of additional k-space lines to obtain an improved estimate of the motion parameters at a higher temporal resolution.

14 . The method of claim 11 , further comprising:
interpolating between the motion parameters estimated for each set of additional k-space lines to obtain an improved estimate of the motion parameters at a higher temporal resolution.

15 . The method of claim 11 , further comprising:
determining redundancies across the motion parameters by:
forming groups of motion parameters such that each group contains motion parameters that are similar to each other; and
dividing the k-space data into bins,
wherein each bin corresponds to a respective group of motion parameters.

16 . A magnetic resonance imaging apparatus comprising:
a radio frequency controller configured to drive an RF-coil comprising a multi-channel coil array; a gradient controller configured to control gradient coils; and a control unit configured to control the radio frequency controller and the gradient contro

Assignees

• Siemens Healthcare Gmbh
• Massachusetts Gen Hospital
• Siemens Healthineers Ag

Inventors

• Polak Daniel
• Splitthoff Daniel Nicolas
• Cauley Stephen Farman

Classifications

• G01R33/56509 Primary

  due to motion, displacement or flow, e.g. gradient moment nulling (G01R33/567 takes precedence) · CPC title

• G01R33/385

  using gradient magnetic field coils · CPC title

• G01R33/5602

  by filtering or weighting based on different relaxation times within the sample, e.g. T1 weighting using an inversion pulse · CPC title

• G01R33/5611

  Parallel magnetic resonance imaging, e.g. sensitivity encoding [SENSE], simultaneous acquisition of spatial harmonics [SMASH], unaliasing by Fourier encoding of the overlaps using the temporal dimension [UNFOLD], k-t-broad-use linear acquisition speed-up technique [k-t-BLAST], k-t-SENSE (structural details of arrays of sub-coils G01R33/3415) · CPC title

• G01R33/4824

  using a non-Cartesian trajectory · CPC title