Determining velocity of cerebrospinal fluid by magnetic resonance imaging

• US 8,903,469 B2
• Filed: 10/02/2009
• Issued: 12/02/2014
• 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
• Primary Examiner(s): KISH, JAMES M
• Application Number:
  US12/572,761
• Publication Number:
  US 20100087730A1
• Time in Patent Office: 1,887 Days
• Field of Search: 600/407, 600410-423
• US Class Current: 600/410
• 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 (MR) imaging apparatus comprising:

an MRI system having components including static and gradient magnetic field generators, at least one radio frequency (RF) coil coupled to an imaging volume, at least one RF transmitter, at least one RF receiver and at least one control computer having a processor and memory configured to control said system components so as to effect;

Time Spatial Labelling Inversion Pulse (Time-SLIP) acquisition of MR image data by repeating an imaging process a plurality of times in synchronization with a trigger signal, the imaging process including application of a labelling pulse to Cerebrospinal Fluid (CSF) flowing inside a subject, and thereafter collecting a magnetic resonance (MR) echo signal after application of an MR excitation pulse to an imaging region including the CSF;

creation of a plurality of images of labelled CSF based on echo signals collected by said repetition of the imaging process;

creation of an average value image based on the plurality of images; and

calculation of variance of signal strengths with respect to each of same positions on the plurality of images based on (a) the plurality of images and (b) the average value image.

2. The apparatus according to claim 1, wherein a group of MR echo signals used for reconstructing one image is collected by application of one excitation pulse.

3. The apparatus according to claim 2, wherein the MR echo signals are collected with a fixed delay time from application of the labelling pulse to application of the excitation pulse.

4. The apparatus according to claim 2, wherein the variance of signal strengths is calculated along a time sequence.

5. The apparatus according to claim 1, wherein the MR echo signals are collected with a fixed delay time from application of the labelling pulse to application of the excitation pulse.

6. The apparatus according to claim 1, wherein the variance of signal strengths is calculated along a time sequence.

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

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

9. The apparatus according to claim 1, further comprising a display configured to display a distribution of the statistics.

10. The apparatus according to claim 9, wherein the display is configured to display the distribution of the statistics by superimposing them on a certain calculation image.

11. The apparatus according to claim 9, wherein the display is configured to change a display mode of the distribution of the statistics in accordance with a value of the statistics.

12. The apparatus according to claim 9, wherein the display is configured to change a display mode of the distribution of the statistics in accordance with a flowing direction of the CSF.

13. An image processing apparatus comprising:

an MRI system having components including static and gradient magnetic field generators, at least one radio frequency (RF) coil coupled to an imaging volume, at least one RF transmitter, at least one RF receiver and at least one control computer having a processor and memory configured to control said system components so as to effect;

Time Spatial Labelling Inversion Pulse (Time-SLIP) acquisition of MR image data by obtaining a plurality of images of labelled Cerebrospinal Fluid (CSF) by repeatedly imaging according to an imaging process in synchronization with a trigger signal, the imaging process including application of a labelling pulse to CSF flowing inside a subject, and thereafter collecting a magnetic resonance (MR) echo signal after application of an excitation pulse to an MR imaging region including the CSF;

creation of an average value image based on the plurality of images; and

calculation of variance of signal strengths with respect to each of same positions on the plurality of images based on (a) the plurality of images and (b) the average value image.

14. An image processing method comprising:

using a configured magnetic resonance imaging (MRI) system to effect Time Spatial Labelling Inversion Pulse (Time-SLIP) acquisition of MR image data by obtaining a plurality of images of labelled Cerebrospinal Fluid (CSF) by repeatedly imaging according to an imaging process in synchronization with a trigger signal, the imaging process including application of a labelling pulse to CSF flowing inside a subject, and thereafter collecting an MR echo signal by application of an MR excitation pulse to an imaging region including the CSF;

creating an average value image based on the plurality of images; and

calculating variance of signal strengths with respect to each of same positions on the plurality of images based on (a) the plurality of images and (b) the average value image.