MAGNETIC RESONANCE IMAGING APPARATUS

• US 20150061675A1
• Filed: 08/28/2014
• Published: 03/05/2015
• Est. Priority Date: 09/05/2013
• Status: Active Grant

• Current Assignee: Toshiba Medical Systems Corporation (Canon Inc.)
• Original Assignee: Toshiba Medical Systems Corporation (Canon Inc.), Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: SAKASHITA, Naotaka, KIMURA, Tokunori
• Granted Patent: US 9,791,533 B2
• Time in Patent Office: Days
• US Class Current: 324/318
• 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 33/56366 Perfusion imaging
• CPC Class Codes: G01R 33/56509 due to motion, displacement or flow, e.g. gradient moment nulling G01R33/567 takes precedence
• 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

Abstract

A magnetic resonance imaging apparatus according to an embodiment includes an execution unit and a generation unit. The execution unit executes first data collection of collecting a data after a predetermined inversion time elapses from a timing in which a labeling pulse is applied to a fluid flowing into an imaging region of a subject and a second data collection of collecting a data without the application of the labeling pulse. The generation unit generates a differential image by using the first data collected by the first data collection and the second data collected by the second data collection. Here, the generation unit generates the differential image by a different differential method according to a relation between the inversion time and a longitudinal relaxation time of the fluid.

Claims

1. A magnetic resonance imaging apparatus comprising:

an execution unit that executes first data collection of collecting a data after a predetermined inversion time elapses from a timing in which a labeling pulse is applied to a fluid flowing into an imaging region of a subject and second data collection of collecting a data without the application of the labeling pulse; and

a generation unit that generates a differential image by using the first data collected by the first data collection and the second data collected by the second data collection,

wherein the generation unit generates the differential image by a different differential method according to a relation between the inversion time and a longitudinal relaxation time of the fluid.

2. The magnetic resonance imaging apparatus according to claim 1,

wherein the execution unit executes data collection after the inversion time elapses from a timing in which a control pulse similar to the labeling pulse is applied to a position where the fluid is not influenced as the second data collection.

3. The magnetic resonance imaging apparatus according to claim 1,

wherein the execution unit executes data collection without an application of a control pulse as the second data collection.

4. The magnetic resonance imaging apparatus according to claim 1,

wherein the generation unit generates the differential image in a different differential method according to whether the inversion time is shorter than the elapse time taken until the longitudinal magnetization of the fluid becomes zero after the application of the labeling pulse or is equal to or longer than the elapse time.

5. The magnetic resonance imaging apparatus according to claim 1,

wherein the generation unit generates a differential data by differentiating the first data and the second data and generates the differential image by executing a Fourier transform on the generated differential data when the inversion time is shorter than the elapse time, and

wherein the generation unit generates a first absolute value image by executing a Fourier transform on the first data, generates a second absolute value image by executing a Fourier transform on the second data, and generates the differential image by differentiating the first absolute value image and the second absolute value image when the inversion time is equal to or longer than the elapse time.

6. The magnetic resonance imaging apparatus according to claim 1,

wherein the generation unit generates a first complex image by executing a Fourier transform on the first data, generates a second complex image by executing a Fourier transform on the second data, and generates the differential image by differentiating the first complex image and the second complex image when the inversion time is shorter than the elapse time, and

wherein the generation unit generates a first absolute value image by executing a Fourier transform on the first data, generates a second absolute value image by executing a Fourier transform on the second data, and generates the differential image by differentiating the first absolute value image and the second absolute value image when the inversion time is equal to or longer than the elapse time.

7. The magnetic resonance imaging apparatus according to claim 1,

wherein the generation unit generates a first real image by executing a Fourier transform on the first data, generates a second real image by executing a Fourier transform on the second data, and generates the differential image by differentiating the first real image and the second real image when the inversion time is shorter than the elapse time, and

wherein the generation unit generates a first absolute value image by executing a Fourier transform on the first data, generates a second absolute value image by executing a Fourier transform on the second data, and generates the differential image by differentiating the first absolute value image and the second absolute value image when the inversion time is equal to or longer than the elapse time.

8. The magnetic resonance imaging apparatus according to claim 7,

wherein the generation unit generates the first real image by performing a phase correction for the first data, and generates the second real image by performing a phase correction for the second data.

9. The magnetic resonance imaging apparatus according to claim 1,

wherein the generation unit generates a first absolute value image by executing a Fourier transform on the first data, and generates a second absolute value image by executing a Fourier transform on the second data,

wherein the generation unit generates the differential image by adding the first absolute value image and the second absolute value image when the inversion time is shorter than the elapse time, and

wherein the generation unit generates the differential image by differentiating the first absolute value image and the second absolute value image when the inversion time is equal to or longer than the elapse time.

10. The magnetic resonance imaging apparatus according to claim 9,

wherein the first absolute value image and the second absolute value image are set so that background signals are negligible or are small compared to a fluid element.

11. The magnetic resonance imaging apparatus according to claim 9,

wherein the generation unit generates the differential image by separating a background part and a fluid part from each other by a mask processing in each of the first absolute value image and the second absolute value image, differentiating an absolute value regardless of the inversion time as for the background part, and adding an absolute value when the inversion time is shorter than the elapse time or differentiating an absolute value when the inversion time is equal to or longer than the elapse time as for the fluid part.

12. The magnetic resonance imaging apparatus according to claim 1, further comprising:

a setting unit that calculates a time until the longitudinal magnetization of the fluid becomes zero after the application of the labeling pulse based on a value T1 of a fluid of an imaging object,

wherein the generation unit uses the time calculated by the setting unit as the elapse time.

13. The magnetic resonance imaging apparatus according to claim 12, further comprising:

a setting unit that calculates a time until the longitudinal magnetization of the fluid becomes zero after the application of the labeling pulse based on a data obtained by a pre-scan of executing plural times the data collection of collecting the data after the predetermined inversion time elapses from a timing in which the labeling pulse is applied while changing the inversion time,

wherein the generation unit uses the time calculated by the setting unit as the elapse time.