Magnetic resonance imaging apparatus that divides imaging region temporally or spatially and acquires data thereof using different readout sequences

• US 10,663,552 B2
• Filed: 10/01/2015
• Issued: 05/26/2020
• Est. Priority Date: 04/04/2013
• Status: Active Grant

• Current Assignee: Toshiba Medical Systems Corporation (Canon Inc.)
• Original Assignee: Toshiba Medical Systems Corporation (Canon Inc.)
• Inventors: Kimura, Tokunori
• Primary Examiner(s): Miller, Daniel R
• Application Number:
  US14/872,319
• Publication Number:
  US 20160018501A1
• Time in Patent Office: 1,699 Days
• Field of Search: 324300-322, 600407-435, 382128-131
• CPC Class Codes: A61B 2576/026 for the brain
• CPC Class Codes: A61B 5/0042 for the brain
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/704 Tables
• CPC Class Codes: A61B 5/7425 Displaying combinations of multiple images regardless of image source, e.g. displaying a reference anatomical image with a live image geometric transforms for image registration G06T3/14; enhancement using image fusion G06T5/50; algorithms for registration of images G06T7/30
• CPC Class Codes: G01R 33/5602 by filtering or weighting based on different relaxation times within the sample, e.g. T1 weighting using an inversion pulse
• CPC Class Codes: G01R 33/5607 by reducing the NMR signal of a particular spin species, e.g. of a chemical species for fat suppression, or of a moving spin species for black-blood imaging
• CPC Class Codes: G01R 33/5608 Data processing and visualization specially adapted for MR, e.g. for feature analysis and pattern recognition on the basis of measured MR data, segmentation of measured MR data, edge contour detection on the basis of measured MR data, for enhancing measured MR data in terms of signal-to-noise ratio by means of noise filtering or apodization, for enhancing measured MR data in terms of resolution by means for deblurring, windowing, zero filling, or generation of gray-scaled images, colour-coded images or images displaying vectors instead of pixels image data processing or generation, in general G06T
• CPC Class Codes: G01R 33/5613 Generating steady state signals, e.g. low flip angle sequences [FLASH]
• CPC Class Codes: G01R 33/5614 using a fully balanced steady-state free precession [bSSFP] pulse sequence, e.g. trueFISP
• CPC Class Codes: G01R 33/56308 Characterization of motion or flow; Dynamic imaging
• CPC Class Codes: G01R 33/56333 Involving spatial modulation of the magnetization within an imaged region, e.g. spatial modulation of magnetization [SPAMM] tagging perfusion imaging based on arterial spin tagging G01R33/56366
• CPC Class Codes: G01R 33/5635 Angiography, e.g. contrast-enhanced angiography [CE-MRA] or time-of-flight angiography [TOF-MRA]
• CPC Class Codes: G01R 33/56366 Perfusion imaging

Abstract

A magnetic resonance imaging apparatus according to an embodiment includes a dividing unit, an acquiring unit, and a combining unit. The dividing unit is configured to divide an imaging region of a patient into at least two temporal or spatial ranges. Of the temporal or spatial ranges, the acquiring unit is configured to perform a data acquiring process on a first range by using a first readout sequence and to perform a data acquiring process on a second range by using a second readout sequence that is different from the first readout sequence in terms of one or both of the type of sequence and an imaging condition. The combining unit is configured to combine an image generated from data acquired by using the first readout sequence with an image generated from data acquired by using the second readout sequence.

Claims

1. A magnetic resonance imaging (MRI) apparatus comprising:

MRI processing circuitry configured to

divide, when performing a data acquiring process at a plurality of different timings by varying a waiting period until starting the data acquiring process after applying an RF wave to label fluid flowing into an imaging region of a patient, the plurality of different timings into at least two temporal ranges of timings; and

perform the data acquiring process at a timing included in a first range of the temporal ranges by using a first readout sequence and perform the data acquiring process at a timing included in a second range of the temporal ranges by using a second readout sequence that is different from the first readout sequence in terms of one or both of a type of sequence and an imaging condition,

wherein the processing circuitry is configured to change, when detecting that the labeled fluid has reached a predetermined position in the imaging region, the readout sequence used for performing the data acquiring process from the first readout sequence to the second readout sequence.

2. The magnetic resonance imaging apparatus according to claim 1, wherein, the processing circuitry is configured to divide, when images of a head of the patient are to be acquired by using an imaging method by which blood serving as the fluid is labeled, the plurality of the timings into a range in which the labeled blood flows through a major artery and a range in which the labeled blood flows through a peripheral artery.

3. The magnetic resonance imaging apparatus according to claim 1, wherein the processing circuitry is configured to divide, when images of the patient are to be acquired by using an imaging method for spatially mapping predetermined quantitative values, the plurality of timings in accordance with characteristics of a target site.

4. The magnetic resonance imaging apparatus according to claim 1, wherein the second readout sequence has a higher Signal-to-Noise (SN) ratio per unit acquisition period than the first readout sequence.

5. The magnetic resonance imaging apparatus according to claim 1, wherein the first readout sequence either has a higher spatial resolution or is more resistant to non-uniformity of a static magnetic field than the second readout sequence.

6. The magnetic resonance imaging apparatus according to claim 1, wherein the processing circuitry is configured to combine the images together, after performing at least one correcting process selected from among a gain correction, a T1 relaxation correction, and an image interpolation, on one or both of the image generated from the data acquired by using the first readout sequence and the image generated from the data acquired by using the second readout sequence.

7. The magnetic resonance imaging apparatus according to claim 1, wherein the processing circuitry is configured to divide the plurality of timings on a basis of one of the following:

anatomical information related to a site serving as an imaged target;

a distribution of static magnetic field intensities measured for a shimming purpose; and

an image used for a purpose of determining a position of the imaging region.

8. The magnetic resonance imaging apparatus according to claim 1, wherein the processing circuitry is further configured to combine an image generated from data acquired by using the first readout sequence with an image generated from data acquired by using the second readout sequence.

9. A magnetic resonance imaging (MRI) apparatus comprising:

MRI processing circuitry configured to

divide, when performing at a plurality of different timings a pattern in which a data acquiring process is started when a waiting period has elapsed since applying an RF wave to label fluid flowing into an imaging region by varying the waiting period, the plurality of timings into at least two temporal ranges of timings; and

perform the data acquiring process at a timing included in a first range of the temporal ranges by using the first readout sequence and perform a data acquiring process at a timing included in a second range of the temporal ranges by using a second readout sequence that is different from the first readout sequence in terms of one or both of a type of sequence and an imaging condition,

wherein the processing circuitry is configured to change, when detecting that the labeled fluid has reached a predetermined position in the imaging region, the readout sequence used for performing the data acquiring process from the first readout sequence to the second readout sequence.

10. A magnetic resonance imaging (MRI) apparatus comprising:

MRI processing circuitry configured to

divide, when performing a data acquiring process at a plurality of different timings by varying a waiting period until starting the data acquiring process after applying an RF wave to label fluid flowing into an imaging region of a patient, the imaging region of the patient into at least two spatial ranges on a basis of the waiting period; and

perform the data acquiring process on a first range of the spatial ranges by using a first readout sequence and perform the data acquiring process on a second range of the spatial ranges by using a second readout sequence that is different from the first readout sequence in terms of one or both of a type of sequence and an imaging condition;

wherein the processing circuitry is configured to change, when detecting that the labeled fluid has reached a predetermined position in the imaging region, the readout sequence used for performing the data acquiring process from the first readout sequence to the second readout sequence.

11. The magnetic resonance imaging apparatus according to claim 10, wherein, the processing circuitry is configured to divide, when images of a head of the patient are to be acquired by using an imaging method by which blood serving as the fluid is labeled, the imaging region into a range in which the labeled blood flows through a major artery and a range in which the labeled blood flows through a peripheral artery.

12. The magnetic resonance imaging apparatus according to claim 10, wherein

the imaging region includes a plurality of sectional regions, and

the processing circuitry is configured to divide the plurality of sectional regions into the at least two spatial ranges.

13. The magnetic resonance imaging apparatus according to claim 10, wherein the first range is a range of shorter waiting period in the at least two spatial ranges and the second range is a range of longer waiting period in the at least two spatial ranges.

14. The magnetic resonance imaging apparatus according to claim 10, wherein the processing circuitry is further configured to generate an image of the imaging region by combining an image generated from data acquired by using the first readout sequence with an image generated from data acquired by using the second readout sequence.

15. A magnetic resonance imaging (MRI) apparatus comprising:

MRI processing circuitry configured to

divide, when acquiring images of a patient using a diffusion imaging method, the imaging region of the patient into at least two spatial ranges, on a basis of a distribution of static magnetic field intensities, and

perform a data acquiring process on a range having larger non-uniformity of a static magnetic field by using a first readout sequence and perform a data acquiring process on a range having smaller non-uniformity of the static magnetic field by using a second readout sequence that is different from the first readout sequence in terms of one or both of a type of sequence and an imaging condition.

16. A magnetic resonance imaging (MRI) apparatus comprising:

MRI processing circuitry configured to

divide, when performing a data acquiring process at a plurality of different timings by varying a waiting period until starting the data acquiring process after applying an RF wave to label fluid flowing into an imaging region of a patient, the plurality of different timings into at least two temporal ranges or the imaging region of the patient into at least two spatial ranges, on a basis of a distribution of static magnetic field intensities,

perform data acquiring processes on an entirety of the imaging region by using each of a first readout sequence and a second readout sequence that is different from the first readout sequence in terms of one or both of a type of sequence and an imaging condition, and

combine an image in a first range out of the image generated from the data acquired by using the first readout sequence with an image in a second range out of the image generated from the data acquired by using the second readout sequence.