# US 12,216,187 B2 · Correcting object movement during MR imaging

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 12,216,187 B2
- Document ID: US12216187B2
- Status: Granted
- Kind: B2
- Application number: 17/225,350
- Filed: 2021-04-08
- Published: 2021-10-21
- Granted: 2025-02-04
- Earliest claimed: 2020-04-16
- Assignees: Siemens Healthineers AG
- Applicants: Siemens Healthcare GmbH
- Inventors: Randall Kroeker; Daniel Kraus; Michael Roas-Löffler; Wilfried Schnell; Daniel Nicolas Splitthoff
- Web page: https://patentgrep.com/patent/US12216187B2

## CPC

- G01R 33/56509: {due to motion, displacement or flow, e.g. gradient moment nulling (G01R33/567 takes precedence)}
- G06T 5/73: Deblurring; Sharpening
- A61B 5/055: involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
- A61B 5/1127: {using markers}
- G06T 7/75: {involving models}
- G06T 2200/04: involving 3D image data
- G06T 2207/10088: Magnetic resonance imaging [MRI]
- G06T 2207/20201: Motion blur correction
- G06T 2207/30088: Skin; Dermal
- G06T 2207/30196: Human being; Person
- G06T 2207/30204: Marker
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

The disclosure relates to a method for correcting a movement of an object occurring during an MR image acquisition. The method includes: determining a motion model describing possible movements of the object based on a defined number of degrees of freedom; detecting a motion of a marker provided on the object with a motion sensor; determining a description of the motion model in a common coordinate system; determining the motion of the marker in the common coordinate system; determining a first motion of the object in the common coordinate system using the description of the motion model, the first motion being the motion that best matches the determined motion of the marker in the common coordinate system using the defined number of degrees of freedom; and correcting the movement of the object based on the determined first motion in order to determine at least one motion corrected MR image.

## Claims

### Claim 1

A method for correcting a movement of an object occurring during a magnetic resonance (MR) image acquisition in which MR signals of the object are detected, the method comprising:
determining a motion model describing possible movements of the object based on a model function having a defined number of degrees of freedom the object is able to use for the movement, wherein the defined number of degrees of freedom of the object is less than all six degrees of freedom possible for rigid body motion;
detecting a motion of a marker provided on the object with a motion sensor;
checking whether the object is configured to carry out the detected motion of the marker taking into account the defined number of degrees of freedom the object is able to use for the movement;
determining a description of the motion model in a common coordinate system having the defined number of degrees of freedom;
determining the motion of the marker in the common coordinate system;
determining a first motion of the object in the common coordinate system using the description of the motion model, wherein the first motion is a motion that best matches the determined motion of the marker in the common coordinate system using only the defined number of degrees of freedom; and
correcting the movement of the object based on the determined first motion in order to determine at least one motion corrected MR image, wherein a corresponding part of the detected motion of the marker is excluded from the correction when the checking identifies that the detected motion of the marker does not originate from the defined number of degrees of freedom of the object.

### Claim 2 (depends on 1)

The method of claim 1, wherein the determining of the motion of the marker comprises determining the motion of the marker in a marker coordinate system, and
wherein the motion of the marker is transferred to the common coordinate system.

### Claim 3 (depends on 1)

The method of claim 1, wherein the first motion is determined such that the first motion is described only using the defined number of degrees of freedom in the common coordinate system, and
wherein the movement of the marker is occurring in a movement period, and for different points in time within the movement period, the movement of the marker is approximated with a corresponding best matching combination of the defined number of degrees of freedom describing the first motion which best matches the determined motion of the marker.

### Claim 4 (depends on 3)

The method of claim 3, wherein the object is head of a human, and
wherein the motion model has a total of three degrees of freedom with two rotational degrees of freedom and one translational degree of freedom.

### Claim 5

A method for correcting a movement of an object occurring during a magnetic resonance (MR) image acquisition in which MR signals of the object are detected, the method comprising:
determining a motion model describing possible movements of the object based on a model function having a defined number of degrees of freedom the object is able to use for the movement;
detecting a motion of a marker provided on the object with a motion sensor;
determining a description of the motion model in a common coordinate system;
determining the motion of the marker in the common coordinate system;
determining a first motion of the object in the common coordinate system using the description of the motion model, wherein the first motion is a motion that best matches the determined motion of the marker in the common coordinate system using the defined number of degrees of freedom; and
correcting the movement of the object based on the determined first motion in order to determine at least one motion corrected MR image,
wherein the object is head of a human,
wherein the motion model has a total of three degrees of freedom with two rotational degrees of freedom and one translational degree of freedom, and
wherein, in the determining of a best matching combination of the three degrees of freedom, the two rotational degrees of freedom are weighted higher than the one translation degree of freedom.

### Claim 6 (depends on 4)

The method of claim 4, wherein the two rotational degrees of freedom comprise a nodding rotation of the head in an up-down direction and a left-right rotation of the head, and
wherein the one translation degree of freedom comprises a cranial caudal movement of the head.

### Claim 7 (depends on 6)

The method of claim 6, further comprising:
determining a rotation axis for the left-right rotation and a pivot point for the nodding rotation of the head based on object related data provided in an MR system configured to generate the MR image of the object.

### Claim 8 (depends on 7)

The method of claim 7, wherein the rotation axis and the pivot point are determined based on MR images obtained from the head.

### Claim 9 (depends on 1)

The method of claim 1, wherein the motion model is determined based on the object having a defined maximum velocity allowed to change a position of the object during the movement.

### Claim 10 (depends on 1)

The method of claim 1, wherein the marker is fixedly attached to the object or is projected onto the object.

### Claim 11 (depends on 1)

The method of claim 1, wherein the object is head of a human, and
wherein the motion model has a total of three degrees of freedom with two rotational degrees of freedom and one translational degree of freedom.

### Claim 12

A method for correcting a movement of an object occurring during a magnetic resonance (MR) image acquisition in which MR signals of the object are detected, the method comprising:
determining a motion model describing possible movements of the object based on a model function having a defined number of degrees of freedom the object is able to use for the movement;
detecting a motion of a marker provided on the object with a motion sensor;
determining a description of the motion model in a common coordinate system;
determining the motion of the marker in the common coordinate system;
determining a first motion of the object in the common coordinate system using the description of the motion model, wherein the first motion is a motion that best matches the determined motion of the marker in the common coordinate system using the defined number of degrees of freedom; and
correcting the movement of the object based on the determined first motion in order to determine at least one motion corrected MR image,
wherein the object is head of a human,
wherein the motion model has a total of three degrees of freedom with two rotational degrees of freedom and one translational degree of freedom,
wherein the two rotational degrees of freedom comprise a nodding rotation of the head in an up-down direction and a left-right rotation of the head, and
wherein the one translation degree of freedom comprises a cranial caudal movement of the head.

### Claim 13 (depends on 12)

The method of claim 12, further comprising:
determining a rotation axis for the left-right rotation and a pivot point for the nodding rotation of the head based on object related data provided in an MR system configured to generate the MR image of the object.

### Claim 14 (depends on 13)

The method of claim 13, wherein the rotation axis and the pivot point are determined based on MR images obtained from the head.

### Claim 15 (depends on 1)

The method of claim 1, wherein the motion of the marker is detected using an image sensor as the motion sensor which is not configured to detect the MR signals of the object.

### Claim 16

A device configured to correct a movement an object occurring during a magnetic resonance (MR) image acquisition in which MR signals of the object are detected, the device comprising:
at least one processing unit; and
a memory comprising instructions, when executed by the at least one processing unit, cause the device to:
determine a motion model describing possible movements of the object based on a defined number of degrees of freedom the object is able to move, wherein the defined number of degrees of freedom of the object is less than all six degrees of freedom possible for rigid body motion;
detect a motion of a marker provided on the object with a motion sensor;
determine a description of the motion model in a common coordinate system having the defined number of degrees of freedom;
determine the motion of the marker in the common coordinate system;
determine a first motion of the object in the common coordinate system using the description of the motion model, wherein the first motion is a motion that best matches the determined motion of the marker in the common coordinate system using only the defined number of degrees of freedom; and
correct the movement of the object based on the determined first motion in order to determine at least one motion corrected MR image,
wherein the object is head of a human,
wherein the motion model has a total of three degrees of freedom with two rotational degrees of freedom and one translational degree of freedom,
wherein the two rotational degrees of freedom comprise a nodding rotation of the head in an up-down direction and a left-right rotation of the head, and
wherein the one translation degree of freedom comprises a cranial caudal movement of the head.

### Claim 17 (depends on 16)

The device of claim 16, wherein the first motion is determined such that the first motion is described only using the defined number of degrees of freedom in the common coordinate system, and
wherein the movement of the marker is occurring in a movement period, and for different points in time within the movement period, the movement of the marker is approximated with a corresponding best matching combination of the defined number of degrees of freedom describing the first motion which best matches the determined motion of the marker.

### Claim 18

A non-transitory computer program comprising program code to be executed by at least one processor of a device, wherein execution of the program code by the at least one processor causes the device to:
determine a motion model describing possible movements of an object undergoing a magnetic resonance (MR) image acquisition based on a defined number of degrees of freedom the object is able to move, wherein the defined number of degrees of freedom of the object is less than all six degrees of freedom possible for rigid body motion;
detect a motion of a marker provided on the object with a motion sensor;
determine a description of the motion model in a common coordinate system;
determine the motion of the marker in the common coordinate system having the defined number of degrees of freedom;
determine a first motion of the object in the common coordinate system using the description of the motion model, wherein the first motion is a motion that best matches the determined motion of the marker in the common coordinate system using only the defined number of degrees of freedom; and
correct a movement of the object based on the determined first motion in order to determine at least one motion corrected MR image,
wherein the object is head of a human,
wherein the motion model has a total of three degrees of freedom with two rotational degrees of freedom and one translational degree of freedom,
wherein the two rotational degrees of freedom comprise a nodding rotation of the head in an up-down direction and a left-right rotation of the head, and
wherein the one translation degree of freedom comprises a cranial caudal movement of the head.