DETERMINING VELOCITY OF CEREBROSPINAL FLUID BY MAGNETIC RESONANCE IMAGING

• US 20120302871A1
• Filed: 08/09/2012
• Published: 11/29/2012
• Est. Priority Date: 10/03/2008
• 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: YAMADA, Shinya, KANAZAWA, Hitoshi
• Granted Patent: US 8,903,470 B2
• Time in Patent Office: Days
• US Class Current: 600/413
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• 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 33/5608 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 33/5616 using gradient refocusing, e.g. EPI
• CPC Class Codes: G01R 33/5617 using RF refocusing, e.g. RARE
• CPC Class Codes: G01R 33/56316 involving phase contrast techniques
• CPC Class Codes: G06T 2207/10088 Magnetic resonance imaging [MRI]
• CPC Class Codes: G06T 2207/20221 Image fusion; Image merging
• CPC Class Codes: G06T 2207/30016 Brain
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06T 7/277 involving stochastic approaches, e.g. using Kalman filters

Abstract

A velocity-image creating unit creates a velocity image that indicates a distribution of velocity components with respect to each of a plurality of images obtained by repeating a plurality of number of times Echo Planar Imaging (EPI) that is capable of obtaining velocity components of a Cerebrospinal Fluid (CSF) flowing inside a subject. A velocity-variance image creating unit calculates variance of velocity components along the time sequence by same position on velocity images by using a plurality of created velocity images. A superimposed-image processing unit then superimposes the distribution of the variance of the velocity components according to the velocity-variance image on an average absolute-value image, and an image display unit displays a superimposed image.

Claims

1. A magnetic resonance imaging apparatus comprising:

a collecting unit configured to repeat imaging according to an imaging method a plurality of times in a synchronized manner with a trigger signal, the imaging method including applying an excitation pulse to an imaging region including a Cerebrospinal Fluid (CSF), reconstructing one image based on a group of echo signals collected by applying one excitation pulse, applying a flow encode gradient magnetic field to give a phase shift proportional to a velocity onto the reconstructed image, and thereby obtaining velocity components of the CSF;

a first creating unit configured to create a velocity image indicating a distribution of the velocity components with respect to each of a plurality of reconstructed images obtained by repeating the imaging;

a second creating unit configured to calculate statistics of the velocity components along a time sequence at the same position on a plurality of velocity images created by the first creating unit, and create a statistic image indicating a distribution of the statistics; and

a display unit configured to display the distribution of the statistics based on the statistic image.

2. The apparatus according to claim 1, wherein the plurality of the reconstructed images are obtained by repeating the imaging with a fixed delay time from applying the labeling pulse to applying the excitation pulse.

3. The apparatus according to claim 1, wherein the second creating unit calculates, as the statistics, variance of the velocity components along a time sequence.

4. The apparatus according to claim 2, wherein the second creating unit calculates, as the statistics, variance of the velocity components along a time sequence.

5. The apparatus according to claim 1, wherein the second creating unit calculates, as the statistics, variance of the velocity components at the same position on the plurality of the reconstructed images.

6. The apparatus according to claim 2, wherein the second creating unit calculates, as the statistics, variance of the velocity components at the same position on the plurality of the reconstructed images.

7. The apparatus according to claim 1, wherein the second creating unit calculates, as the statistics, one of a maximum value and a minimum value of the velocity components at the same position on the plurality of the reconstructed images.

8. The apparatus according to claim 2, wherein the second creating unit calculates, as the statistics, one of a maximum value and a minimum value of the velocity components at the same position on the plurality of the reconstructed images.

9. The apparatus according to claim 1, wherein the second creating unit calculates, as the statistics, an average value of the velocity components within a certain proportion from a top of all velocity components when the velocity components are listed in descending order of value at the same position on the plurality of the reconstructed images.

10. The apparatus according to claim 2, wherein the second creating unit calculates, as the statistics, an average value of the velocity components within a certain proportion from a top of all velocity components when the velocity components are listed in descending order of value at the same position on the plurality of the reconstructed images.

11. The apparatus according to claim 1, wherein the trigger signal is a biological signal of the subject.

12. The apparatus according to claim 2, wherein the trigger signal is a biological signal of the subject.

13. The apparatus according to claim 1, wherein the trigger signal is a signal generated in a fixed cycle.

14. The apparatus according to claim 2, wherein the trigger signal is a signal generated in a fixed cycle.

15. The apparatus according to claim 1, wherein the display unit displays the distribution of the statistics by superimposing on a certain calculation image.

16. The apparatus according to claim 2, wherein the display unit displays the distribution of the statistics by superimposing on a certain calculation image.

17. The apparatus according to claim 1, wherein the display unit changes a display mode of the distribution of the statistics in accordance with a value of the statistics.

18. The apparatus according to claim 1, wherein the display unit changes a display mode of the distribution of the statistics in accordance with a flowing direction of the CSF.

19. An image processing apparatus comprising:

a first creating unit configured to create a velocity image indicating a distribution of the velocity components with respect to each of a plurality of reconstructed images by repeating an imaging according to an imaging method a plurality of times in a synchronized manner with a trigger signal, the imaging method including applying an excitation pulse to an imaging region including a CSF, reconstructing one image based on a group of echo signals collected by applying one excitation pulse, applying a flow encode gradient magnetic field to give a phase shift proportional to a velocity onto the reconstructed image, and thereby obtaining velocity components of the CSF;

a second creating unit configured to calculate statistics of the velocity components along a time sequence at the same position on a plurality of velocity images created by the first creating unit, and creates a statistic image indicating a distribution of the statistics; and

a display unit configured to display the distribution of the statistics based on the statistic image.

20. An image processing method comprising:

creating a velocity image indicating a distribution of the velocity components with respect to each of a plurality of reconstructed images by repeating an imaging according to an imaging method a plurality of times in a synchronized manner with a trigger signal, the imaging method including applying an excitation pulse to an imaging region including a CSF, reconstructing one image based on a group of echo signals collected by applying one excitation pulse, applying a flow encode gradient magnetic field to give a phase shift proportional to a velocity onto the reconstructed image, and thereby obtaining velocity components of the CSF;

calculating statistics of the velocity components along a time sequence at the same position on a plurality of velocity images;

creating a statistic image indicating a distribution of the statistics; and

displaying the distribution of the statistics based on the statistic image.