# US 6,295,465 B1 · Myocardial perfusion studies using magnetic resonance imaging

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- Number: US 6,295,465 B1
- Document ID: US6295465B1
- Status: Granted
- Kind: B1
- Application number: 09/251,550
- Filed: 1999-02-17
- Granted: 2001-09-25
- Earliest claimed: 1999-02-17
- Assignees: Siemens Medical Systems, Inc.
- Inventors: Orlando P. Simonetti
- Web page: https://patentgrep.com/patent/US6295465B1

## CPC

- G01R 33/5601: {involving use of a contrast agent for contrast manipulation, e.g. a paramagnetic, super-paramagnetic, ferromagnetic or hyperpolarised contrast agent}
- A61B 5/055: involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
- G01R 33/563: of moving material, e.g. flow contrast angiography
- 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

Gadolinium-based MR contrast agent is administered to a patient. Acquisition of MR data begins at the latest when the bolus of MR contrast agent reaches the patient's heart and continues throughout the first-pass of contrast agent through the coronary circulation. Advantageously, the acquisition is carried out using a T1-weighted, three-dimensional gradient echo sequence that is synchronized to the patient's cardiac cycle to acquire MR data only during diastole, and a T1-weighting magnetization preparation such as inversion-recovery or saturation-recovery is used.

## Claims

### Claim 1

A method of conducting a myocardial perfusion study on a living patient using magnetic resonance (MR) imaging, comprising the following steps:
administering a bolus of an MR contrast agent to the patient's circulatory system;
determining a time interval when the bolus makes its first pass through the patient's heart;
acquiring, during said time interval, three-dimensional MR image data of the heart, said acquiring step being gated to the patient's cardiac cycle, acquiring MR image data only during diastole, and producing MR data with high spatial resolution.

### Claim 2 (depends on 1)

The method of claim 1, wherein said acquiring step is T1-weighted and uses a three-dimensional MR pulse sequence.

### Claim 3 (depends on 2)

The method of claim 2, wherein the T1-weighting of the MR image data is emphasized using inversion-recovery magnetization preparation.

### Claim 4 (depends on 2)

The method of claim 2, wherein the T1-weighting of the MR image data is emphasized using saturation-recovery magnetization preparation.

### Claim 5

A method of carrying out a myocardial perfusion study on a living patient using magnetic resonance (MR) imaging, comprising the following steps:
administering a bolus of an MR contrast agent to the patient's circulatory system; and
acquiring MR image data while the bolus is making its first pass through the patient's heart, said acquiring step being synchronized with the patient's cardiac cycle and comprising the steps of
emphasizing T1-weighting of the MR signal from the myocardium,
acquiring, during diastole in each of a series of cardiac cycles and using a T1-weighted three-dimensional MR pulse sequence, lines of MR data from the patient's heart, and
repeating said emphasizing and line-acquiring steps until sufficient MR data has been collected to enable reconstruction of a high spatial resolution image of the heart.

### Claim 6 (depends on 5)

The method of claim 5, wherein the MR pulse sequence is a gradient-echo sequence.

### Claim 7 (depends on 5)

The method of claim 5, wherein the patient is instructed to hold the patient's breath during the MR image data acquisition step.

### Claim 8 (depends on 5)

The method of claim 5, wherein said emphasizing step comprises the step of using magnetization preparation.

### Claim 9 (depends on 8)

The method of claim 8, wherein said emphasizing step comprises the step of using inverse-recovery magnetization preparation.

### Claim 10 (depends on 8)

The method of claim 8, wherein said emphasizing step comprises the step of using saturation-recovery magnetization preparation.

### Claim 11 (depends on 5)

The method of claim 5, wherein said step of acquiring MR image data comprises the steps of monitoring progress of the MR contrast agent through the patient's circulatory system and beginning acquisition of MR image data when MR contrast agent enters the left ventricle of the patient's heart.