Magnetic resonance imaging apparatus and magnetic resonance imaging method

• US 20080061780A1
• Filed: 09/10/2007
• Published: 03/13/2008
• Est. Priority Date: 09/13/2006
• Status: Active Grant

• Current Assignee: Toshiba Medical Systems Corporation (Canon Inc.), Tokai University Educational System
• Original Assignee: Toshiba Medical Systems Corporation (Canon Inc.), Tokai University Educational System
• Inventors: Kanazawa, Hitoshi, Yamada, Shinya, Kimura, Tokunori, Umeda, Masaaki
• Granted Patent: US 7,880,464 B2
• Time in Patent Office: Days
• US Class Current: 324/309
• CPC Class Codes: A61B 5/0263 using NMR
• CPC Class Codes: A61B 5/7285 for synchronising or triggering a physiological measurement or image acquisition with a physiological event or waveform, e.g. an ECG signal A61B6/5205, A61B6/541, A61B8/5207, A61B8/543 take precedence
• 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 33/5614 using a fully balanced steady-state free precession [bSSFP] pulse sequence, e.g. trueFISP
• CPC Class Codes: G01R 33/5615 Echo train techniques involving acquiring plural, differently encoded, echo signals after one RF excitation, e.g. using gradient refocusing in echo planar imaging [EPI], RF refocusing in rapid acquisition with relaxation enhancement [RARE] or using both RF and gradient refocusing in gradient and spin echo imaging [GRASE]
• CPC Class Codes: G01R 33/5616 using gradient refocusing, e.g. EPI
• CPC Class Codes: G01R 33/5617 using RF refocusing, e.g. RARE
• CPC Class Codes: G01R 33/56308 Characterization of motion or flow; Dynamic imaging
• CPC Class Codes: G01R 33/56316 involving phase contrast techniques
• 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 33/56509 due to motion, displacement or flow, e.g. gradient moment nulling G01R33/567 takes precedence
• CPC Class Codes: G01R 33/5673 Gating or triggering based on a physiological signal other than an MR signal, e.g. ECG gating or motion monitoring using optical systems for monitoring the motion of a fiducial marker
• CPC Class Codes: G01R 33/5676 Gating or triggering based on an MR signal, e.g. involving one or more navigator echoes for motion monitoring and correction

Abstract

A magnetic resonance imaging apparatus includes an imaging unit which applies a labeling pulse to invert a spin included in a labeling region within part of a imaging region and then collects a echo signal from a time point when an inversion time has passed from the application of the labeling pulse, and a control unit, the control unit controlling the imaging unit so that the echo signal in the imaging region is collected a plurality of times with variations in the inversion time, the control unit also controlling the imaging unit so that a time ranging from a reference time point within a biological signal obtained from a subject to the application of the labeling pulse is a time determined in accordance with the inversion time.

Claims

1. A magnetic resonance imaging apparatus which generates a magnetic resonance image on the basis of an echo signal regarding a spin included in an imaging region of a subject, the apparatus comprising:

an imaging unit which applies a labeling pulse to invert the spin included in a labeling region within part of the imaging region and then collects the echo signal from a time point when an inversion time has passed from the application of the labeling pulse; and

a control unit, the control unit controlling the imaging unit so that the echo signal in the imaging region is collected a plurality of times with variations in the inversion time, the control unit also controlling the imaging unit so that a time ranging from a reference time point within a biological signal obtained from the subject to the application of the labeling pulse is a time determined in accordance with the inversion time.

2. A magnetic resonance imaging apparatus which generates a magnetic resonance image on the basis of an echo signal regarding a spin included in an imaging region of a subject, the apparatus comprising:

an imaging unit which applies a labeling pulse to invert the spin included in a labeling region within part of the imaging region and then applies an excitation pulse at a time point when an inversion time has passed from the application of the labeling pulse in order to collect the resulting echo signal; and

a control unit, the control unit controlling the imaging unit so that the echo signal in the imaging region is collected a plurality of times with variations in the inversion time, the control unit also controlling the imaging unit so that a time ranging from a reference time point within a biological signal obtained from the subject to the application of the excitation pulse is constant regardless of the inversion time in the plurality of collections of the echo signal.

3. A magnetic resonance imaging apparatus comprising:

an acquisition unit which acquires an echo signal regarding a spin included in an imaging region of a subject in accordance with a predetermined pulse sequence;

a reconstruction unit which reconstructs an image of the inside of the imaging region in accordance with the acquired echo signal;

a labeling unit which inverts the spin included in a labeling region within part of the imaging region to conduct labeling; and

a control unit, the control unit controlling the labeling unit and the acquisition unit so that a cycle of conducting the labeling and acquiring the echo signal from a time point when a first time has passed from a time point of the labeling is carried out a plurality of times with variations in the first time, the control unit also controlling the labeling unit and the acquisition unit so that each of the plurality of cycles is started at a time point when a second time which increases or decreases contrary to the size of the first time in each cycle has passed from a periodic reference time point.

4. The magnetic resonance imaging apparatus according to claim 3, wherein the control unit decides the second time so that a time required from the reference time point to a time point when the pulse sequence is started is the same in each of the plurality of cycles.

5. The magnetic resonance imaging apparatus according to claim 3, wherein the control unit decides the reference time point on the basis of a synchronization signal.

8. The magnetic resonance imaging apparatus according to claim 3, further comprising:

a unit which calculates the moving distance of the labeled spin on the basis of at least two images of interest out of images reconstructed by the reconstruction unit in accordance with the echo signal acquired in each of the plurality of cycles, and sequentially displays the images of interest in an order corresponding to the calculated moving distance.

6. A magnetic resonance imaging apparatus comprising:

an acquisition unit which acquires an echo signal regarding a spin included in an imaging region of a subject in accordance with a predetermined pulse sequence;

a reconstruction unit which reconstructs an image of the inside of the imaging region in accordance with the acquired echo signal;

a labeling unit which inverts the spin included in a labeling region within part of the imaging region to conduct labeling; and

a control unit, the control unit controlling the labeling unit and the acquisition unit so that a cycle of conducting the labeling and acquiring the echo signal from a time point when a given first time has passed from a time point of the labeling is carried out a plurality of times without changing the labeling region, the control unit also controlling the labeling unit and the acquisition unit so that each of the plurality of cycles is started at a time point when a given second time has passed from a periodic reference time point.

7. The magnetic resonance imaging apparatus according to claim 6, further comprising:

a unit which generates a composite image of at least two of images reconstructed by the reconstruction unit on the basis of the echo signal acquired in each of the plurality of cycles.

9. The magnetic resonance imaging apparatus according to claim 6, wherein the control unit decides the reference time point on the basis of a synchronization signal.

10. The magnetic resonance imaging apparatus according to claim 9, wherein the control unit uses an electrocardiographic signal regarding the subject as the synchronization signal.

11. A magnetic resonance imaging apparatus comprising:

an acquisition unit which acquires an echo signal regarding a spin included in an imaging region of a subject in accordance with a predetermined pulse sequence;

a reconstruction unit which reconstructs an image of the inside of the imaging region in accordance with the acquired echo signal;

a labeling unit which inverts the spin included in a labeling region within part of the imaging region to conduct labeling;

an observation unit which repetitively acquires a magnetic resonance signal from within the labeling region and observes a change of the flow velocity of a fluid in the labeling region on the basis of a change of the repetitively acquired magnetic resonance signal; and

a control unit, the control unit controlling the labeling unit and the acquisition unit so that a cycle of conducting the labeling and acquiring the echo signal from a time point when a predetermined first time has passed after the labeling is carried out a plurality of times, the control unit also controlling the labeling unit and the acquisition unit so that the cycle is started at a time point when a predetermined second time has passed from a reference time point at which the observed change of the flow velocity coincides with a predetermined state.

12. The magnetic resonance imaging apparatus according to claim 11, wherein the observation unit only acquires the magnetic resonance signal from an observation region within part of the labeling region.

13. The magnetic resonance imaging apparatus according to claim 11, wherein the observation region is a cerebral aqueduct.

14. A magnetic resonance imaging apparatus comprising:

an acquisition unit which acquires an echo signal regarding a spin included in an imaging region of a subject in accordance with a predetermined pulse sequence;

a reconstruction unit which reconstructs an image of the inside of the imaging region in accordance with the acquired echo signal;

a labeling unit which inverts the spin included in the imaging region and then inverts the spin included in each of a plurality of labeling regions within part of the imaging region to conduct labeling; and

a control unit, the control unit controlling the labeling unit and the acquisition unit so that a cycle of conducting the labeling and acquiring the echo signal from a time point when a predetermined first time has passed from a time point of the labeling is carried out a plurality of times, the control unit also controlling the labeling unit and the acquisition unit so that the cycle is started at a time point when a predetermined second time has passed from a periodic reference time point.

15. A magnetic resonance imaging apparatus comprising:

an acquisition unit which acquires an echo signal regarding a spin included in an imaging region of a subject in accordance with a predetermined pulse sequence;

a reconstruction unit which reconstructs an image of the inside of the imaging region in accordance with the acquired echo signal;

a labeling unit which inverts the spin included in a labeling region within part of the imaging region to conduct labeling;

a control unit, the control unit controlling the labeling unit and the acquisition unit so that a cycle of conducting the labeling and acquiring the echo signal from a time point when a predetermined first time has passed after the labeling is carried out a plurality of times, the control unit also controlling the labeling unit and the acquisition unit so that each of the plurality of cycles is started at a time point when a predetermined second time has passed from a periodic reference time point;

a unit which displays, as a positioning image, one of the plurality of images reconstructed on the basis of the echo signal acquired in each of the plurality of cycles; and

a unit which accepts a designation of an imaging section on the positioning image.

16. A magnetic resonance imaging apparatus having access to a storage device, the apparatus comprising:

an acquisition unit which acquires an echo signal regarding a spin included in an imaging region of a subject in accordance with a predetermined pulse sequence;

a reconstruction unit which reconstructs an image of the inside of the imaging region in accordance with the acquired echo signal;

a labeling unit which inverts the spin included in a labeling region within part of the imaging region to conduct labeling;

a control unit, the control unit controlling the labeling unit and the acquisition unit so that a cycle of conducting the labeling and acquiring the echo signal from a time point when a predetermined first time has passed after the labeling is carried out a plurality of times, the control unit also controlling the labeling unit and the acquisition unit so that each of the plurality of cycles is started at a time point when a predetermined second time has passed from a periodic reference time point; and

a unit which sets the labeling region on the basis of information stored in the storage device.

17. The magnetic resonance imaging apparatus according to claim 16, including the storage device therein.

18. The magnetic resonance imaging apparatus according to claim 16, further comprising:

a unit which saves, in the storage device, information indicating the labeling region set on the basis of an instruction of a user.

19. A magnetic resonance imaging method which generates a magnetic resonance image on the basis of an echo signal regarding a spin included in an imaging region of a subject, the method comprising:

applying a labeling pulse to invert the spin included in a labeling region within part of the imaging region and then collecting the echo signal from a time point when an inversion time has passed from the application of the labeling pulse; and

collecting the echo signal in the imaging region a plurality of times with variations in the inversion time, and also controlling the application of the labeling pulse and the collection so that a time ranging from a reference time point within a biological signal obtained from the subject to the application of the labeling pulse is a time determined in accordance with the inversion time.

20. A magnetic resonance imaging method which generates a magnetic resonance image on the basis of an echo signal regarding a spin included in an imaging region of a subject, the method comprising:

applying a labeling pulse to invert the spin included in a labeling region within part of the imaging region and then applying an excitation pulse at a time point when an inversion time has passed from the application of the labeling pulse in order to collect the resulting echo signal; and

controlling the application of the labeling pulse and the collection so that the echo signal in the imaging region is collected a plurality of times with variations in the inversion time, and also controlling the application of the labeling pulse and the collection so that a time ranging from a reference time point within a biological signal obtained from the subject to the application of the excitation pulse is constant regardless of the inversion time in the plurality of collections of the echo signal.

21. A magnetic resonance imaging method comprising:

acquiring an echo signal regarding a spin included in an imaging region of a subject in accordance with a predetermined pulse sequence;

inverting the spin included in a labeling region within part of the imaging region to conduct labeling;

controlling the labeling and the acquisition so that a cycle of conducting the labeling and acquiring the echo signal from a time point when a first time has passed from a time point of the labeling is carried out a plurality of times with variations in the first time, and also controlling the labeling and the acquisition so that each of the plurality of cycles is started at a time point when a second time which increases or decreases contrary to the size of the first time in each cycle has passed from a periodic reference time point; and

reconstructing an image of the inside of the imaging region in accordance with the acquired echo signal.

22. A magnetic resonance imaging method comprising:

acquiring an echo signal regarding a spin included in an imaging region of a subject in accordance with a predetermined pulse sequence;

inverting the spin included in a labeling region within part of the imaging region to conduct labeling;

controlling the labeling and the acquisition so that a cycle of conducting the labeling and acquiring the echo signal from a time point when a given first time has passed from a time point of the labeling is carried out a plurality of times without changing the labeling region, and also controlling the labeling and the acquisition so that each of the plurality of cycles is started at a time point when a given second time has passed from a periodic reference time point; and

reconstructing an image of the inside of the imaging region in accordance with the acquired echo signal.

23. A magnetic resonance imaging method comprising:

acquiring an echo signal regarding a spin included in an imaging region of a subject in accordance with a predetermined pulse sequence;

inverting the spin included in a labeling region within part of the imaging region to conduct labeling;

repetitively acquiring a magnetic resonance signal from within the labeling region and observing a change of the flow velocity of a fluid in the labeling region on the basis of a change of the repetitively acquired magnetic resonance signal;

controlling the labeling and the acquisition so that a cycle of conducting the labeling and acquiring the echo signal from a time point when a predetermined first time has passed after the labeling is carried out a plurality of times, and also controlling the labeling and the acquisition so that the cycle is started at a time point when a predetermined second time has passed from a reference time point at which the observed change of the flow velocity coincides with a predetermined state; and

reconstructing an image of the inside of the imaging region in accordance with the acquired echo signal.

24. A magnetic resonance imaging method comprising:

acquiring an echo signal regarding a spin included in an imaging region of a subject in accordance with a predetermined pulse sequence;

inverting the spin included in the imaging region and then inverting the spin included in each of a plurality of labeling regions within part of the imaging region to conduct labeling; and

controlling the labeling and the acquisition so that a cycle of conducting the labeling and acquiring the echo signal from a time point when a predetermined first time has passed from a time point of the labeling is carried out a plurality of times, and also controlling the labeling and the acquisition so that the cycle is started at a time point when a predetermined second time has passed from a periodic reference time point;

reconstructing an image of the inside of the imaging region in accordance with the acquired echo signal.

25. A magnetic resonance imaging method comprising:

acquiring an echo signal regarding a spin included in an imaging region of a subject in accordance with a predetermined pulse sequence;

inverting the spin included in a labeling region within part of the imaging region to conduct labeling;

controlling the labeling and the acquisition so that a cycle of conducting the labeling and acquiring the echo signal from a time point when a predetermined first time has passed after the labeling is carried out a plurality of times, and also controlling the labeling and the acquisition so that each of the plurality of cycles is started at a time point when a predetermined second time has passed from a periodic reference time point;

reconstructing an image of the inside of the imaging region in accordance with the acquired echo signal;

displaying, as a positioning image, one of the plurality of images reconstructed on the basis of the echo signal acquired in each of the plurality of cycles; and

accepting a designation of an imaging section on the positioning image.

26. A magnetic resonance imaging method in a magnetic resonance imaging apparatus having access to a storage device, the method comprising:

acquiring an echo signal regarding a spin included in an imaging region of a subject in accordance with a predetermined pulse sequence;

inverting the spin included in a labeling region within part of the imaging region to conduct labeling;

controlling the labeling and the acquisition so that a cycle of conducting the labeling and acquiring the echo signal from a time point when a predetermined first time has passed from a time point of the labeling is carried out a plurality of times, and also controlling the labeling and the acquisition so that each of the plurality of cycles is started at a time point when a predetermined second time has passed from a periodic reference time point;

setting the labeling region on the basis of information stored in the storage device; and

reconstructing an image of the inside of the imaging region in accordance with the acquired echo signal.