MAGNETIC RESONANCE IMAGING APPARATUS AND MAGNETIC RESONANCE IMAGING METHOD

• US 20100041982A1
• Filed: 08/11/2009
• Published: 02/18/2010
• Est. Priority Date: 08/12/2008
• Status: Active Grant

• Current Assignee: Toshiba Medical Systems Corporation (Canon Inc.)
• Original Assignee: Toshiba Medical Systems Corporation (Canon Inc.)
• Inventors: Kitane, Shinichi
• Granted Patent: US 9,687,171 B2
• Time in Patent Office: Days
• US Class Current: 600/419
• CPC Class Codes: A61B 5/0037 Performing a preliminary scan, e.g. a prescan for identifying a region of interest
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• CPC Class Codes: A61B 5/0263 using NMR
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• 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 33/20 involving magnetic resonance medical aspects A61B5/055; magnetic resonance gyrometers G01C19/60
• CPC Class Codes: G01R 33/285 Invasive instruments, e.g. catheters or biopsy needles, specially adapted for tracking, guiding or visualization by NMR
• CPC Class Codes: G01R 33/3415 comprising arrays of sub-coils , i.e. phased-array coils with flexible receiver channels
• CPC Class Codes: G01R 33/44 using nuclear magnetic resonance [NMR] G01R33/24, G01R33/62 take precedence
• CPC Class Codes: G01R 33/483 with selection of signals or spectra from particular regions of the volume, e.g. in vivo spectroscopy
• CPC Class Codes: G01R 33/54 Signal processing systems, e.g. using pulse sequences ; Generation or control of pulse sequences; Operator console
• CPC Class Codes: G01R 33/56 Image enhancement or correction, e.g. subtraction or averaging techniques , e.g. improvement of signal-to-noise ratio and resolution
• CPC Class Codes: G01R 33/56316 involving phase contrast techniques
• 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 33/5673 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 a trigger generating unit, a blood flow image generating unit and a control unit. The trigger generating unit acquires blood flow information of an object and generates a trigger based on the blood flow information. The blood flow image generating unit acquires imaging data with using the trigger and generates blood flow image data. The control unit controls so as to repeatedly perform a probe sequence for acquiring the blood flow information and an imaging sequence for acquiring the imaging data alternately.

Claims

1. A magnetic resonance imaging apparatus comprising:

a trigger generating unit configured to acquire blood flow information of an object by acquiring magnetic resonance signals from the object and generate a trigger based on the blood flow information;

a blood flow image generating unit configured to acquire imaging data from the object with using the trigger and generate blood flow image data with using the imaging data; and

a control unit configured to control so as to repeatedly perform a probe sequence for acquiring the blood flow information and an imaging sequence for acquiring the imaging data alternately.

2. A magnetic resonance imaging apparatus of claim 1,

wherein said trigger generating unit is configured to acquire an intensity of a signal from blood flow in a blood vessel to be a target, an absolute value of the intensity of the signal from the blood flow or a luminance value of image data generated from the signal from the blood flow as the blood flow information.

3. A magnetic resonance imaging apparatus of claim 1,

wherein said trigger generating unit is configured to acquire a velocity of blood flow in a blood vessel to be a target as the blood flow information.

4. A magnetic resonance imaging apparatus of claim 1,

wherein said trigger generating unit is configured to acquire a temporal phase shift amount of a signal from blood flow in a blood vessel to be a target as the blood flow information.

5. A magnetic resonance imaging apparatus of claim 4,

wherein said trigger generating unit is configured to acquire a difference in phase between a signal corresponding to each time phase and a signal to be a reference as the temporal phase shift amount.

6. A magnetic resonance imaging apparatus of claim 4,

wherein said trigger generating unit is configured to acquire a difference in phase between signals adjacent to each other in time as the temporal phase shift amount.

7. A magnetic resonance imaging apparatus of claim 1,

wherein said trigger generating unit is configured to acquire the blood flow information by exciting a local region including a blood vessel to be a target at a downstream side lower than a region for acquiring the imaging data.

8. A magnetic resonance imaging apparatus of claim 1,

wherein said trigger generating unit is configured to acquire a velocity of blood flow in a blood vessel to be a target as the blood flow information by exciting a local region including the blood vessel to be the target with a sequence under a phase contrast method.

9. A magnetic resonance imaging apparatus of claim 1,

wherein said trigger generating unit is configured to generate the trigger when it is determined that a value indicating the blood flow information is within a range specified by thresholds preset to the value indicating the blood flow information.

10. A magnetic resonance imaging apparatus of claim 1,

wherein said trigger generating unit is configured to acquire k-space data corresponding to one line passing though a center of k-space by exciting a local region including a blood vessel to be a target with a sequence of a field echo type or a spin echo type and generate the trigger when it is determined that a value indicating the blood flow information is within a range specified by thresholds preset to the value indicating the blood flow information, the value being obtained from the k-space data.

11. A magnetic resonance imaging apparatus of claim 1,

wherein said trigger generating unit is configured to generate a trigger for a first imaging sequence to be performed in a period in which a value indicating the blood flow information becomes a local maximal vale when it is determined that the value indicating the blood flow information becomes within a first range in a local maximal value side specified by thresholds preset to the value indicating the blood flow information and a trigger for a second imaging sequence to be performed in a period in which a value indicating the blood flow information becomes a local minimal vale when it is determined that the value indicating the blood flow information becomes within a second range in a local minimal value side specified by other thresholds preset to the value indicating the blood flow information, and

said blood flow image generating unit is configured to generate the blood flow image data by subtraction processing between first imaging data acquired by the first imaging sequence and second imaging data acquired by the second imaging sequence.

12. A magnetic resonance imaging apparatus of claim 1,

wherein said trigger generating unit is configured to acquire the magnetic resonance signals repeatedly at a certain interval and generate the trigger only when it is determined that a value indicating the blood flow information is within a range specified by thresholds preset to the value indicating the blood flow information, the value being obtained from the magnetic resonance signals.

13. A magnetic resonance imaging apparatus of claim 1,

wherein said trigger generating unit is configured to acquire the magnetic resonance signals repeatedly until it is determined that a value indicating the blood flow information is within a range specified by thresholds preset to the value indicating the blood flow information and generate the trigger when it is determined that the value indicating the blood flow information is within the range, the value being obtained from the magnetic resonance signals.

14. A magnetic resonance imaging apparatus of claim 1,

wherein said blood flow image generating unit is configured to generate the blood flow image data as T2 weighted image data by acquiring the imaging data with a non-contrast-enhanced three dimensional scan using a sequence of a spin echo type.

15. A magnetic resonance imaging apparatus of claim 1,

wherein said blood flow image generating unit is configured to acquire the imaging data using a steady state free precession sequence.

16. A magnetic resonance imaging apparatus of claim 1,

wherein said blood flow image generating unit is configured to acquire saturated blood signals flowing into an imaging section as the imaging data with a sequence of a field echo type by applying a saturation pulse to blood flow to be a target and using inflow effect under a time of flight method without using contrast medium.

17. A magnetic resonance imaging method comprising:

acquiring blood flow information of an object by acquiring magnetic resonance signals from the object and generating a trigger based on the blood flow information;

acquiring imaging data from the object with using the trigger and generating blood flow image data with using the imaging data; and

controlling so as to repeatedly perform a probe sequence for acquiring the blood flow information and an imaging sequence for acquiring the imaging data alternately.