Magnetic resonance imaging apparatus

Abstract

Provided is an MRI apparatus. In the MRI apparatus, a data collection unit repetitively performs a tag mode of applying an RF wave to at least an upstream portion of an imaging area to perform fluid labeling of a fluid flown into the imaging area and, after a lapse of an inversion time from application of the RF wave, performing magnetic resonance data collection, while changing the inversion time. An image reconstruction unit reconstructs a plurality of tag images corresponding to a plurality of different inversion times based on the magnetic resonance data collected in the tag mode. A reference image generation unit generates a reference image based on the plurality of the tag images. A fluid image generation unit generates a subtraction image between each of the tag images and the reference image as a fluid image.

What is claimed is: 
     
       1. A magnetic resonance imaging apparatus comprising:
 a memory; and 
 a processor comprising processing circuitry, wherein the memory stores instructions, which when executed by the processor, cause the magnetic resonance imaging apparatus to perform operations comprising: 
 a data collection unit that repetitively performs performing a tag mode of applying an RF wave to at least an upstream portion of an imaging area to label a fluid flown into the imaging area and, after a lapse of an inversion time from application of the RF wave, performing magnetic resonance data collection, while changing the inversion time; 
 an image reconstruction unit that reconstructsreconstructing a plurality of tag images corresponding to a plurality of different inversion times based on magnetic resonance data collected in the tag mode; 
 a reference image generation unit that generatesgenerating a reference image based on the plurality of the tag images; and 
 a fluid image generation unit that generatesgenerating a subtraction image between each of the tag images and the reference image as a fluid image. 
 
     
     
       2. The magnetic resonance imaging apparatus according to  claim 1 ,
 wherein the reference image generation unit generates  instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to generate the reference image by using the tag image exhibiting a small difference in signal intensity between a blood flow portion and a background tissue among the plurality of the tag images. 
 
     
     
       3. The magnetic resonance imaging apparatus according to  claim 1 , further comprising wherein the instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to:
 a display unit that displaysdisplay a plurality of the fluid images generated by the fluid image generation unit as behavior expression in a cine display format or a parallel display format. 
 
     
     
       4. The magnetic resonance imaging apparatus according to  claim 1 ,
 wherein at the time of performing the tag mode, the data collection unit applies the instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to apply a non-selective inversion recovery pulse to a range including the imaging area and the fluid flown into the imaging area so that the magnetic resonance data collection is started at the time when a longitudinal magnetization of at least one type of tissue among tissues included in the imaging area becomes nearly zero. 
 
     
     
       5. The magnetic resonance imaging apparatus according to  claim 1 ,
 wherein the data collection unit applies instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to apply a saturation pulse to a range including the imaging area just before the magnetic resonance data collection is started. 
 
     
     
       6. The magnetic resonance imaging apparatus according to  claim 1 ,
 wherein the reference image generation unit selects instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to select among the tag images an image obtained before the fluid is flown into the imaging area or an image obtained after magnetization of the fluid in the imaging area is relaxed, and generates to generate the reference image based on the selected image. 
 
     
     
       7. The magnetic resonance imaging apparatus according to  claim 6 ,
 wherein the reference image generation unit selects instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to select a plurality of images obtained before the fluid is flown into the imaging area or a plurality of images obtained after magnetization of the fluid in the imaging area is relaxed, and generates to generate an average image of the plurality of the selected images as the reference image. 
 
     
     
       8. The magnetic resonance imaging apparatus according to  claim 1 ,
 wherein the data collection unit further performs instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to perform a control mode a given number of times that is smaller than the number of performances of the tag mode, the control mode being an imaging mode of applying an RF wave to the imaging area without labeling a fluid through application of an RF wave to an upstream portion of the imaging area and, after a lapse of an inversion time from application of the RF wave, performing to perform magnetic resonance data collection, 
 wherein the image reconstruction unit further reconstructs instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to reconstruct control images as many as a number smaller than that of the tag images, based on the magnetic resonance data collected in the control mode, 
 wherein the reference image generation unit generates instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to generate one reference image or a plurality of control images for subtraction corresponding to the plurality of different inversion times by using the control images as many as a number smaller than that of the tag images, and 
 wherein the fluid image generation unit generates instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to generate a subtraction image between each of the tag images and the reference image or generates to generate a subtraction image between the tag image and the generated control image for each inversion time. 
 
     
     
       9. The magnetic resonance imaging apparatus according to  claim 8 ,
 wherein the data collection unit performs instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to perform the control mode under a collection condition which is the same as the collection condition used at the time of performing the tag mode. 
 
     
     
       10. The magnetic resonance imaging apparatus according to  claim 1 ,
 wherein the data collection unit uses instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to use Steady State Free Precession (SSFP), Gradient Echo (GRE), Fast Spin Echo (FSE), or Echo Planar Imaging (EPI) as an imaging sequence for magnetic resonance data collection. 
 
     
     
       11. The magnetic resonance imaging apparatus according to  claim 1 ,
 wherein the fluid image generation unit further performs instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to perform longitudinal relaxation correction on the fluid image according to the inversion time based on a T1 value of the fluid. 
 
     
     
       12. The magnetic resonance imaging apparatus according to  claim 1 ,
 wherein the data collection unit applies instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to apply the RF wave for performing the fluid labeling to the upstream portion or downstream portion of the imaging area and applies to apply no RF wave to the imaging area until a predetermined inversion time elapses from application of the RF wave. 
 
     
     
       13. A magnetic resonance imaging apparatus comprising:
 a memory; and 
 a processor comprising processing circuitry, wherein the memory stores instructions, which when executed by the processor, cause the magnetic resonance imaging apparatus to perform operations comprising: 
 a data collection unit that repetitively performsrepetitively performing a control mode of applying an RF wave to an imaging area without labeling a fluid through application of an RF wave to an upstream portion of the imaging area and, after a lapse of an inversion time from application of the RF wave, performing magnetic resonance data collection,while changing the inversion time; 
 an image reconstruction unit that reconstructs a plurality of control images corresponding to a plurality of different inversion times based on the magnetic resonance data collected in the control mode; 
 a reference image generation unit that generates generating a reference image based on the plurality of thecontrol images; and 
 a fluid image generation unit that generatesgenerating subtraction images between each of the control images and the reference image as fluid images. 
 
     
     
       14. The magnetic resonance imaging apparatus according to  claim 13 ,
 wherein the reference image generation unit generates instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to generate the reference image by using the control image exhibiting a small difference in signal intensity between a blood flow portion and a background tissue among the plurality of thecontrol images. 
 
     
     
       15. The magnetic resonance imaging apparatus according to  claim 13 , further comprising: a display unit that displays wherein the instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to display a plurality of the fluid images generated by the fluid image generation unit as behavior expression in a cine display format or a parallel display format. 
     
     
       16. The magnetic resonance imaging apparatus according to  claim 13 ,
 wherein the instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to, at the time of performing the control mode, the data collection unit applies apply a non-selective inversion recovery pulse to a range including the imaging area and the fluid flown into the imaging area so that the magnetic resonance data collection is started at the time when a longitudinal magnetization of at least one type of tissue among tissues included in the imaging area becomes nearly zero. 
 
     
     
       17. The magnetic resonance imaging apparatus according to  claim 13 ,
 wherein the data collection unit applies instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to apply a saturation pulse to a range including the imaging area just before the magnetic resonance data collection is started. 
 
     
     
       18. The magnetic resonance imaging apparatus according to  claim 13 ,
 wherein the reference image generation unit selects instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to select among the control images an image obtained before the fluid is flown into the imaging area or an image obtained after magnetization of the fluid in the imaging area is relaxed, and generates to generate the reference image based on the selected image. 
 
     
     
       19. The magnetic resonance imaging apparatus according to  claim 18 ,
 wherein the reference image generation unit selects instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to select a plurality of images obtained before the fluid is flown into the imaging area or a plurality of images obtained after magnetization of the fluid in the imaging area is relaxed, and generates to generate an average image of the plurality of the selected images as the reference image. 
 
     
     
       20. A magnetic resonance imaging apparatus comprising:
 a memory; and 
 a processor comprising processing circuitry, wherein the memory stores instructions, which when executed by the processor, cause the magnetic resonance imaging apparatus to perform operations comprising: 
 a data collection unit that repetitively performsrepetitively performing an imaging mode of applying an RF wave to a subject to label a fluid flown into the subject and, after a lapse of an inversion time from application of the RF wave, performing magnetic resonance data collection while changing the inversion time; 
 an image reconstruction unit that reconstructsreconstructing a plurality of images corresponding to a plurality of different inversion times based on the magnetic resonance data; 
 a reference image generation unit that generatesgenerating a reference image based on the plurality of the images; and 
 a fluid image generation unit that generatesgenerating a subtraction image between each of the images and the reference image as a fluid image. 
 
     
     
       21. A magnetic resonance imaging apparatus comprising:
 a memory; and 
 a processor comprising processing circuitry, wherein the memory stores instructions, which when executed by the processor, cause the magnetic resonance imaging apparatus to perform operations comprising: 
 a data collection unit that repetitively performsrepetitively performing an imaging mode of applying an RF wave to a subject to label a fluid flown into the subject and, after a lapse of an inversion time from application of the RF wave, performing magnetic resonance data collection of an imaging area while changing the inversion time; 
 an image reconstruction unit that reconstructsreconstructing a plurality of images corresponding to a plurality of different inversion times based on the magnetic resonance data; and  
 a fluid image generation unit that generatesgenerating a fluid image by generating a subtraction image between at least one of the plurality of the images and a reference image, the reference image being an image obtained before the labeled fluid is flown into the imaging area or an image obtained after magnetization of a fluid in the imaging area is relaxed. 
 
     
     
       22. A magnetic resonance imaging apparatus comprising:
 a memory; and   a processor comprising processing circuitry, wherein the memory stores instructions, which when executed by the processor, cause the magnetic resonance imaging apparatus to perform operations comprising:   repetitively performing a tag mode to collect magnetic resonance data while changing an inversion time, and perform a control mode to collect magnetic resonance data a given number of times that is smaller than the number of performances of the tag mode;   reconstructing a plurality of tag images corresponding to a plurality of different inversion times based on the magnetic resonance data collected in the tag mode, and reconstructing one or more control images as many as a number smaller than that of the tag images based on the magnetic resonance data collected in the control mode; and   generating a subtraction image for each inversion time using the tag images and the one or more control images.   
     
     
       23. The magnetic resonance imaging apparatus according to claim 22, wherein,
 the tag mode applies a first RF wave to an area that includes an upstream portion of an imaging area to label a fluid flown into the imaging area and, after a lapse of the inversion time from application of the first RF wave, performs the magnetic resonance data collection, and   the control mode applies a second RF wave to an area that does not include the upstream portion and, after a lapse of the inversion time from application of the second RF wave, performs the magnetic resonance data collection.   
     
     
       24. The magnetic resonance imaging apparatus according to claim 22, wherein
 the instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to generate a first image using the one or more control images, and   to generate the subtraction image for each inversion time by generating a subtraction image between each of the plurality of tag images and the first image.   
     
     
       25. The magnetic resonance imaging apparatus according to claim 22, wherein
 the instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to generate a plurality of second images corresponding to the plurality of different inversion times using the one or more control images, and   to generate the subtraction image for each inversion time by generating a subtraction image between the tag image and the second image for each inversion time.   
     
     
       26. A magnetic resonance imaging apparatus comprising:
 a memory; and   a processor comprising processing circuitry, wherein the memory stores instructions, which when executed by the processor, cause the magnetic resonance imaging apparatus to perform operations comprising:   performing a tag mode, and performing a control mode a given number of times that is smaller than the number of performances of the tag mode, the tag mode applying a first RF wave to at least an upstream portion of an imaging area to label a fluid flown into the imaging area and, after a lapse of an inversion time from application of the first RF wave, performing collection of magnetic resonance data, while changing the inversion time, the control mode performing collection of magnetic resonance data without labeling a fluid through application of an RF wave to the upstream portion of the imaging area;   reconstructing a plurality of tag images corresponding to a plurality of different inversion times based on the magnetic resonance data collected in the tag mode, and reconstructing one or more control images as many as a number smaller than that of the tag images based on the magnetic resonance data collected in the control mode; and   generating a subtraction image for each inversion time using the tag images and the one or more control images.   
     
     
       27. The magnetic resonance imaging apparatus according to claim 26, wherein:
 the tag mode applies the first RF wave to an area that includes the upstream portion, and   the control mode applies a second RF wave to an area that does not include the upstream portion and, after a lapse of the inversion time from application of the second RF wave, performs collection of the magnetic resonance data.   
     
     
       28. The magnetic resonance imaging apparatus according to claim 26, wherein
 the instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to generate a first image using the one or more control images, and   to generate the subtraction image for each inversion time by generating a subtraction image between each of the plurality of tag images and the first image.   
     
     
       29. The magnetic resonance imaging apparatus according to claim 26, wherein
 the instructions, when executed by the processor, cause the magnetic resonance imaging apparatus to generate a plurality of second images corresponding to the plurality of different inversion times using the one or more control images, and   to generate the subtraction image for each inversion time by generating a subtraction image between the tag image and the second image for each inversion time.   
     
     
       30. A magnetic resonance imaging method comprising:
 repetitively performing a tag mode to collect magnetic resonance data while changing an inversion time;   performing a control mode to collect magnetic resonance data a given number of times that is smaller than the number of performances of the tag mode;   reconstructing a plurality of tag images corresponding to a plurality of different inversion times based on the magnetic resonance data collected in the tag mode;   reconstructing one or more control images as many as a number smaller than that of the tag images based on the magnetic resonance data collected in the control mode; and   generating a subtraction image for each inversion time using the tag images and the one or more control images.   
     
     
       31. A magnetic resonance imaging method comprising:
 repetitively performing a tag mode, the tag mode applying an RF wave to at least an upstream portion of an imaging area to label a fluid flown into the imaging area and, after a lapse of an inversion time from application of the RF wave, performing collection of magnetic resonance data, while changing the inversion time;   performing a control mode a given number of times that is smaller than the number of performances of the tag mode, the control mode performing collection of magnetic resonance data without labeling a fluid through application of an RF wave to the upstream portion of the imaging area;   reconstructing a plurality of tag images corresponding to a plurality of different inversion times based on the magnetic resonance data collected in the tag mode;   reconstructing one or more control images as many as a number smaller than that of the tag images based on the magnetic resonance data collected in the control mode; and   generating a subtraction image for each inversion time using the tag images and the one or more control images.