# US 12,007,458 B2 · Magnetic resonance imaging apparatus and magnetic resonance imaging method

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- Number: US 12,007,458 B2
- Document ID: US12007458B2
- Status: Granted
- Kind: B2
- Application number: 16/504,455
- Filed: 2019-07-08
- Published: 2021-01-14
- Granted: 2024-06-11
- Earliest claimed: 2019-07-08
- Assignees: Canon Medical Systems Corporation; The Regents of the University of California
- Applicants: Canon Medical Systems Corporation; The Regents of the University of California
- Inventors: Mitsue Miyazaki; Christine Chung
- Web page: https://patentgrep.com/patent/US12007458B2

## CPC

- G01R 33/4828: {Resolving the MR signals of different chemical species, e.g. water-fat imaging}
- A61B 5/055: involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
- G01R 33/50: based on the determination of relaxation times {, e.g. T1 measurement by IR sequences; T2 measurement by multiple-echo sequences}
- G01R 33/543: {Control of the operation of the MR system, e.g. setting of acquisition parameters prior to or during MR data acquisition, dynamic shimming, use of one or more scout images for scan plane prescription (G01R33/546 takes precedence)}
- G01R 33/546: {Interface between the MR system and the user, e.g. for controlling the operation of the MR system or for the design of pulse sequences}
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

A magnetic resonance imaging apparatus according to an embodiment includes sequence controlling circuitry and processing circuitry. The sequence controlling circuitry acquires a first piece of data by executing a first pulse sequence having a first Echo Time (TE) value, to acquire a second piece of data by executing a second pulse sequence having a second TE value different from the first TE value, and to acquire a third piece of data by executing a third pulse sequence having a third TE value different from the first and the second TE values. The processing circuitry extracts a signal related to water, a signal related to a first fat, and a signal related to a second fat, on the basis of the first piece of data, the second piece of data, and the third piece of data.

## Claims

### Claim 1

A magnetic resonance imaging apparatus, comprising:
sequence controlling circuitry configured to acquire a first piece of data by executing a first pulse sequence having a first Echo Time (TE) value, to acquire a second piece of data by executing a second pulse sequence having a second TE value different from the first TE value, and to acquire a third piece of data by executing a third pulse sequence having a third TE value different from the first and the second TE values, wherein the first pulse sequence, the second pulse sequence, and the third pulse sequence are executed such that a center frequency is equal to a frequency corresponding to a chemical shift of a fat, and wherein the second pulse sequence is executed such that the second TE value causes a signal of protons of a first fat and a signal of protons of a second fat to have phases opposite to each other; and
processing circuitry configured to extract a signal related to water, a signal related to the first fat, and a signal related to the second fat, based on the first piece of data, the second piece of data, and the third piece of data, and based on values of a chemical shift of the water, a chemical shift of the first fat, and a chemical shift of the second fat;
wherein the sequence controlling circuitry is further configured to
execute the first pulse sequence by using the first TE value that causes a signal of the first fat and a signal of the second fat to be in-phase with each other,
execute the second pulse sequence by using the second TE value that causes the signal of the first fat and the signal of the second fat to be out of phase with each other, and
execute the third pulse sequence by using the third TE value that causes the signal of the first fat and the signal of the second fat to be out of phase with each other, and
the sequence controlling circuitry is configured to execute only three pulse sequences, which are the first pulse sequence, the second pulse sequence, and the third pulse sequence.

### Claim 2 (depends on 1)

The magnetic resonance imaging apparatus according to claim 1, wherein the sequence controlling circuitry is further configured to execute the first pulse sequence, the second pulse sequence, and the third pulse sequence as a linked one acquisition while maintaining a receiver gain at a same level.

### Claim 3 (depends on 1)

The magnetic resonance imaging apparatus according to claim 1, wherein the processing circuitry is further configured to extract the signal related to the water, the signal related to the first fat, and the signal related to the second fat, based on values of a chemical shift of the water, a chemical shift of the first fat, and a chemical shift of the second fat.

### Claim 4 (depends on 1)

The magnetic resonance imaging apparatus according to claim 1, wherein the sequence controlling circuitry is further configured to execute the first pulse sequence, the second pulse sequence, and the third pulse sequence such that the center frequency is equal to the frequency corresponding to a chemical shift of the fat, wherein the fat is aliphatic fat.

### Claim 5 (depends on 1)

The magnetic resonance imaging apparatus according to claim 1, wherein the processing circuitry is further configured to generate one selected from between a two-dimensional image and a three-dimensional image, based on the signal related to the water, the signal related to the first fat, and the signal related to the second fat.

### Claim 6 (depends on 1)

The magnetic resonance imaging apparatus according to claim 1, wherein
the processing circuitry is further configured to receive, from a user, an input indicating types of the first fat and the second fat and, based on a result of the received input, and establish a setting about the first pulse sequence, the second pulse sequence, and the third pulse sequence, and
the sequence controlling circuitry is further configured to execute the first pulse sequence, the second pulse sequence, and the third pulse sequence, while maintaining a receiver gain at a same level.

### Claim 7 (depends on 1)

The magnetic resonance imaging apparatus according to claim 1, wherein
the processing circuitry is further configured to receive, from a user, an input indicating a plurality of types of fat including an input indicating types of the first fat and the second fat and, based on a result of the received input, and establish a setting about three or more pulse sequences including the first pulse sequence, the second pulse sequence, and the third pulse sequence,
the sequence controlling circuitry is further configured to execute the three or more pulse sequences, and
the processing circuitry is further configured to extract signals each related to a different one of the plurality of types of fat, based on pieces of data obtained from the three or more pulse sequences executed by the sequence controlling circuitry.

### Claim 8

A magnetic resonance imaging method implemented by a magnetic resonance imaging apparatus, the method comprising:
acquiring a first piece of data by executing a first pulse sequence having a first Echo Time (TE) value; acquiring a second piece of data by executing a second pulse sequence having a second TE value different from the first TE value, wherein the second TE value causes a signal of protons of a first fat and a signal of protons of a second fat to have phases opposite to each other;
acquiring a third piece of data by executing a third pulse sequence having a third TE value different from the first and the second TE values, wherein the first pulse sequence, the second pulse sequence, and the third pulse sequence are executed such that a center frequency is equal to a frequency corresponding to a chemical shift of a fat; and
extracting a signal related to water, a signal related to the first fat, and a signal related to the second fat, based on the first piece of data, the second piece of data, and the third piece of data, and based on values of a chemical shift of the water, a chemical shift of the first fat, and a chemical shift of the second fat;
wherein the method further comprises
executing the first pulse sequence by using the first TE value that causes a signal of the first fat and a signal of the second fat to be in-phase with each other,
executing the second pulse sequence by using the second TE value that causes the signal of the first fat and the signal of the second fat to be out of phase with each other, and
executing the third pulse sequence by using the third TE value that causes the signal of the first fat and the signal of the second fat to be out of phase with each other; and
the method comprises executing only three pulse sequences, which are the first pulse sequence, the second pulse sequence and the third pulse sequence.

### Claim 9 (depends on 7)

The magnetic resonance imaging method according to claim 7, wherein the fat is aliphatic fat.

### Claim 10

A magnetic resonance imaging apparatus, comprising:
sequence controlling circuitry configured to acquire a first piece of data by executing a first pulse sequence having a first Echo Time (TE) value, to acquire a second piece of data by executing a second pulse sequence having a second TE value different from the first TE value, and to acquire a third piece of data by executing a third pulse sequence having a third TE value different from the first and the second TE values, wherein the first pulse sequence, the second pulse sequence, and the third pulse sequence are executed such that a center frequency is equal to a frequency corresponding to a chemical shift of a fat; and
processing circuitry configured to extract a signal related to water, a signal related to a first fat, and a signal related to a second fat, based on the first piece of data, the second piece of data, and the third piece of data, and based on values of a chemical shift of the water, a chemical shift of the first fat, and a chemical shift of the second fat;
wherein the second pulse sequence is executed such that the second TE value causes a signal of aliphatic protons and a signal of olefinic fat protons to have phases opposite to each other;
the sequence controlling circuitry is further configured to
execute the first pulse sequence by using the first TE value that causes a signal of the first fat and a signal of the second fat to be in-phase with each other,
execute the second pulse sequence by using the second TE value that causes the signal of the first fat and the signal of the second fat to be out of phase with each other, and
execute the third pulse sequence by using the third TE value that causes the signal of the first fat and the signal of the second fat to be out of phase with each other; and
the sequence controlling circuitry is configured to execute only three pulse sequences, which are the first pulse sequence, the second pulse sequence, and the third pulse sequence.

### Claim 11

A magnetic resonance imaging apparatus, comprising:
sequence controlling circuitry configured to acquire a first piece of data by executing a first pulse sequence having a first Echo Time (TE) value, to acquire a second piece of data by executing a second pulse sequence having a second TE value different from the first TE value, and to acquire a third piece of data by executing a third pulse sequence having a third TE value different from the first and the second TE values, wherein the first pulse sequence, the second pulse sequence, and the third pulse sequence are executed such that a center frequency is equal to a frequency corresponding to a chemical shift of a fat; and
processing circuitry configured to extract a signal related to water, a signal related to a first fat, and a signal related to a second fat, based on the first piece of data, the second piece of data, and the third piece of data, and based on values of a chemical shift of the water, a chemical shift of the first fat, and a chemical shift of the second fat;
wherein the second pulse sequence is executed such that the second TE value causes a signal of aliphatic protons and a signal of unsaturated fat protons to have phases opposite to each other;
the sequence controlling circuitry is further configured to
execute the first pulse sequence by using the first TE value that causes a signal of the first fat and a signal of the second fat to be in-phase with each other,
execute the second pulse sequence by using the second TE value that causes the signal of the first fat and the signal of the second fat to be out of phase with each other, and
execute the third pulse sequence by using the third TE value that causes the signal of the first fat and the signal of the second fat to be out of phase with each other; and
the sequence controlling circuitry is configured to execute only three pulse sequences, which are the first pulse sequence, the second pulse sequence, and the third pulse sequence.

### Claim 12

A magnetic resonance imaging apparatus, comprising:
sequence controlling circuitry configured to acquire a first piece of data by executing a first pulse sequence having a first Echo Time (TE) value, to acquire a second piece of data by executing a second pulse sequence having a second TE value different from the first TE value, and to acquire a third piece of data by executing a third pulse sequence having a third TE value different from the first and the second TE values, wherein the first pulse sequence, the second pulse sequence, and the third pulse sequence are executed such that a center frequency is equal to a frequency corresponding to a chemical shift of a fat; and
processing circuitry configured to extract a signal related to water, a signal related to a first fat, and a signal related to a second fat, based on the first piece of data, the second piece of data, and the third piece of data, and based on values of a chemical shift of the water, a chemical shift of the first fat, and a chemical shift of the second fat;
wherein the second pulse sequence is executed such that the second TE value causes a signal of aliphatic protons and a signal of polyunsaturated fat protons to have phases opposite to each other;
the sequence controlling circuitry is further configured to
execute the first pulse sequence by using the first TE value that causes a signal of the first fat and a signal of the second fat to be in-phase with each other,
execute the second pulse sequence by using the second TE value that causes the signal of the first fat and the signal of the second fat to be out of phase with each other, and
execute the third pulse sequence by using the third TE value that causes the signal of the first fat and the signal of the second fat to be out of phase with each other; and
the sequence controlling circuitry is configured to execute only three pulse sequences, which are the first pulse sequence, the second pulse sequence, and the third pulse sequence.

### Claim 13

A magnetic resonance imaging method implemented by a magnetic resonance imaging apparatus, the method comprising:
acquiring a first piece of data by executing a first pulse sequence having a first Echo Time (TE) value;
acquiring a second piece of data by executing a second pulse sequence having a second TE value different from the first TE value;
acquiring a third piece of data by executing a third pulse sequence having a third TE value different from the first and the second TE values, wherein the first pulse sequence, the second pulse sequence, and the third pulse sequence are executed such that a center frequency is equal to a frequency corresponding to a chemical shift of a fat; and
extracting a signal related to water, a signal related to a first fat, and a signal related to a second fat, based on the first piece of data, the second piece of data, and the third piece of data,
wherein the second pulse sequence is executed such that the second TE value causes a signal of aliphatic protons and a signal of olefinic fat protons to have phases opposite to each other, based on values of a chemical shift of the water, a chemical shift of the first fat, and a chemical shift of the second fat; and
the method further comprises
executing the first pulse sequence by using the first TE value that causes a signal of the first fat and a signal of the second fat to be in-phase with each other,
executing the second pulse sequence by using the second TE value that causes the signal of the first fat and the signal of the second fat to be out of phase with each other, and
executing the third pulse sequence by using the third TE value that causes the signal of the first fat and the signal of the second fat to be out of phase with each other; and
the method comprises executing only three pulse sequences, which are the first pulse sequence, the second pulse sequence and the third pulse sequence.

### Claim 14

A magnetic resonance imaging method implemented by a magnetic resonance imaging apparatus, the method comprising:
acquiring a first piece of data by executing a first pulse sequence having a first Echo Time (TE) value;
acquiring a second piece of data by executing a second pulse sequence having a second TE value different from the first TE value;
acquiring a third piece of data by executing a third pulse sequence having a third TE value different from the first and the second TE values, wherein the first pulse sequence, the second pulse sequence, and the third pulse sequence are executed such that a center frequency is equal to a frequency corresponding to a chemical shift of a fat; and
extracting a signal related to water, a signal related to a first fat, and a signal related to a second fat, based on the first piece of data, the second piece of data, and the third piece of data, and based on values of a chemical shift of the water, a chemical shift of the first fat, and a chemical shift of the second fat;
wherein the second pulse sequence is executed such that the second TE value causes a signal of aliphatic protons and a signal of unsaturated fat protons to have phases opposite to each other;
the method further comprises
executing the first pulse sequence by using the first TE value that causes a signal of the first fat and a signal of the second fat to be in-phase with each other,
executing the second pulse sequence by using the second TE value that causes the signal of the first fat and the signal of the second fat to be out of phase with each other, and
executing the third pulse sequence by using the third TE value that causes the signal of the first fat and the signal of the second fat to be out of phase with each other; and
the method comprises executing only three pulse sequences, which are the first pulse sequence, the second pulse sequence and the third pulse sequence.

### Claim 15

A magnetic resonance imaging method implemented by a magnetic resonance imaging apparatus, the method comprising:
acquiring a first piece of data by executing a first pulse sequence having a first Echo Time (TE) value;
acquiring a second piece of data by executing a second pulse sequence having a second TE value different from the first TE value;
acquiring a third piece of data by executing a third pulse sequence having a third TE value different from the first and the second TE values, wherein the first pulse sequence, the second pulse sequence, and the third pulse sequence are executed such that a center frequency is equal to a frequency corresponding to a chemical shift of a fat; and
extracting a signal related to water, a signal related to a first fat, and a signal related to a second fat, based on the first piece of data, the second piece of data, and the third piece of data, and based on values of a chemical shift of the water, a chemical shift of the first fat, and a chemical shift of the second fat;
wherein the second pulse sequence is executed such that the second TE value causes a signal of aliphatic protons and a signal of polyunsaturated fat protons to have phases opposite to each other;
the method further comprises
executing the first pulse sequence by using the first TE value that causes a signal of the first fat and a signal of the second fat to be in-phase with each other,
executing the second pulse sequence by using the second TE value that causes the signal of the first fat and the signal of the second fat to be out of phase with each other, and
executing the third pulse sequence by using the third TE value that causes the signal of the first fat and the signal of the second fat to be out of phase with each other; and
the method comprises executing only three pulse sequences, which are the first pulse sequence, the second pulse sequence and the third pulse sequence.