Magnetic resonance imaging apparatus and magnetic resonance imaging method

Patent metadata

Field	Value
Publication number	US-9687171-B2
Application number	US-53895709-A
Country	US
Kind code	B2
Filing date	Aug 11, 2009
Priority date	Aug 12, 2008
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

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.

First claim

What is claimed is:

1. A magnetic resonance imaging (MRI) apparatus comprising:
static and gradient magnetic field generators, at least one radio frequency (RF) coil configured to be coupled to an imaging volume, RF transmitter and receiver circuits coupled to the RF coil and at least one programmable computer connected to control said gradient magnetic field generator, said RF transmitter and receiver circuits, the at least one programmable computer being configured to
provide a probe sequence and acquire blood flow information of an object within an imaging scan to acquire magnetic resonance signals from the object and to generate a trigger for an imaging sequence, also within said imaging scan, using the blood flow information acquired in the probe sequence, wherein a data acquisition region of the probe sequence is set to a local region including at least a target blood vessel, and the blood flow information is acquired from magnetic resonance signals obtained from the target blood vessel;
acquire imaging data from the object during said imaging sequence initiated by the trigger and to generate blood flow image data using the acquired imaging data; and repeatedly and alternately perform, during said imaging scan, (a) said probe sequence acquiring the blood flow information and (b) the imaging sequence acquiring the imaging data,
wherein the local region to which the probe sequence is applied is located downstream of a region to which the imaging sequence is applied.

2. The magnetic resonance imaging apparatus of claim 1 , wherein the at least one programmable computer being further configured to acquire
a signal from blood flow in a target blood vessel, and an absolute value of intensity of the signal or a luminance value of image data generated from the signal as the blood flow information.

3. The magnetic resonance imaging apparatus of claim 1 , wherein the at least one programmable computer being further configured to acquire
a velocity of blood flow in a target blood vessel as the blood flow information.

4. The magnetic resonance imaging apparatus of claim 1 , wherein the at least one programmable computer being further configured to acquire a temporal phase shift amount of a signal from blood flow in a target blood vessel as the blood flow information.

5. The magnetic resonance imaging apparatus of claim 4 , wherein the at least one programmable computer being further configured to acquire
a difference in phase between a signal corresponding to each time phase and a reference signal as the temporal phase shift amount.

6. The magnetic resonance imaging apparatus of claim 4 , wherein the at least one programmable computer being further configured to acquire
a difference in phase between signals adjacent to each other in time as the temporal phase shift amount.

7. The magnetic resonance imaging apparatus of claim 1 , wherein the at least one programmable computer being further configured to acquire
the blood flow information by NMR RF (nuclear magnetic resonance radio frequency) excitation of a local region including a target blood vessel at a downstream side of a region for acquiring the imaging data.

8. The magnetic resonance imaging apparatus of claim 1 , wherein the at least one programmable computer being further configured to acquire
a velocity of blood flow in a target blood vessel as the blood flow information by NMR RF (nuclear magnetic resonance radio frequency) excitation of a local region including the target blood vessel with a sequence using a phase contrast MRI method.

9. The magnetic resonance imaging apparatus of claim 1 , wherein the at least one programmable computer being further configured to generate
the trigger when it is determined that the blood flow information is within a range specified by preset thresholds.

10. A magnetic resonance imaging apparatus of claim 1 , wherein the at least one programmable computer being further configured to acquire
k-space data corresponding to one line passing through a center of k-space by NMR RF (nuclear magnetic resonance radio frequency) excitation of a local region including a target blood vessel with a sequence of a field echo or a spin echo type and to generate the trigger is generated when it is determined that the blood flow information is within a range specified by preset thresholds, the threshold values being obtained from the k-space data.

11. The magnetic resonance imaging apparatus of claim 1 , wherein the at least one programmable computer being further configured to
(a) generate a trigger for a first imaging sequence to be performed in a period when the blood flow information is within a local maximal range specified by preset thresholds and (b) generate a trigger for a second imaging sequence to be performed in a period when the blood flow information is within a local minimal range specified by further preset thresholds, and
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. The magnetic resonance imaging apparatus of claim 1 , wherein the at least one programmable computer being further configured to acquire
the magnetic resonance signals repeatedly at a predetermined interval and the trigger is generated only when it is determined that the blood flow information is within a range specified by preset thresholds obtained from the magnetic resonance signals.

13. The magnetic resonance imaging apparatus of claim 1 , wherein the at least one programmable computer being further configured to acquire
the magnetic resonance signals repeatedly until it is determined that the blood flow information is within a range specified by preset thresholds and the trigger is generated when it is determined that the blood flow information is within the range based on the magnetic resonance signals.

14. The magnetic resonance imaging apparatus of claim 1 , wherein the at least one programmable computer being further configured to generate
the blood flow image data as T 2 weighted image data by acquiring the imaging data with a non-contrast-enhanced three dimensional MRI scan using a spin echo type imaging sequence.

15. The magnetic resonance imaging apparatus of claim 1 , wherein the at least one programmable computer being further configured to acquire
the imaging data using a steady state free precession MRI sequence.

16. The magnetic resonance imaging apparatus of claim 1 , wherein the at least one programmable computer being further configured to acquire
saturated blood signals flowing into an imaging section as the imaging data using a field echo type MRI sequence wherein a saturation pulse is applied to a target blood flow and using an inflow effect of a time of flight method without using contrast medium.

17. A magnetic resonance imaging (MRI) method comprising: operating an MRI system including static and gradient magnetic field generators, at least one radio frequency (RF) coil configured to be coupled to an imaging volume, RF transmitter and receiver circuits coupled to the RF coil and at least one programmed computer to
(a) acquire blood flow information of an object by acquiring magnetic resonance signals from the object and generating a trigger, for an imaging sequence during an imaging scan that includes both the probe sequence and the imaging sequence, using the blood flow information acquired in the probe sequence, wherein a data acquisition region of the probe sequence is set to a local region including at least a target blood ves

Assignees

• Kitane Shinichi
• Toshiba Medical Sys Corp

Inventors

• Kitane Shinichi

Classifications

• A61B5/0037

  Performing a preliminary scan, e.g. a prescan for identifying a region of interest · CPC title

• G01R33/5676

  Gating or triggering based on an MR signal, e.g. involving one or more navigator echoes for motion monitoring and correction · CPC title

• G01R33/5673

  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 title

• G01R33/56316

  involving phase contrast techniques · CPC title

• G01R33/3415

  comprising arrays of sub-coils {, i.e. phased-array coils with flexible receiver channels} · CPC title