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US 11,080,825 B2Granted
Magnetic resonance imaging apparatus and image processing method
AssigneeHitachi, Ltd.
InventorsKousuke Itou, Shinji Kurokawa, Masahiro Takizawa
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AssigneeHitachi, Ltd.
InventorsKousuke Itou, Shinji Kurokawa, Masahiro Takizawa
Estimating the term…
Provided is a novel aliasing elimination technique capable of suppressing noise amplification in an aliasing elimination calculation in parallel imaging and the like. The technique utilizes the fact that a phase of an image (a true image that is one of a plurality of images) to be separated from a main captured image obtained with the plurality of images superimposed is basically the same as a phase of an image obtained at a low resolution, to obtain a phase difference between a phase of a low-resolution image and a phase of the main captured image, and separates the true image by calculation using the phase difference and a pixel value of the main captured image. At this time, the low-resolution image is obtained by each of a plurality of receiving coils, and the true image is calculated after multiplying a plurality of low-resolution images by a complex number that minimizes the noise amplification.
A magnetic resonance imaging apparatus, comprising:
A magnetic resonance imaging apparatus, comprising:
An image processing method for separating a true image from a measurement image obtained by magnetic resonance imaging and superimposed with a plurality of images including the true image, comprising:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
Scaling of whole images or parts thereof, e.g. expanding or contracting: based on super-resolution, i.e. the output image resolution being higher…
Image enhancement or restoration: denoising; Smoothing
Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves:…
Using spatially selective excitation of the volume of interest, e.g. selecting non-orthogonal or inclined slices: of multiple slices
About 11 years 8 months of term left · ends 5 Jul 2038 (estimated)
The present invention relates to a technique for eliminating aliasing of an image or separating superimposed images in a magnetic resonance imaging apparatus (hereinafter referred to as an MRI apparatus).
The MRI apparatus is an imaging apparatus for obtaining the image from a signal obtained by a magnetic resonance phenomenon of predetermined nuclear spins in a subject tissue, and phase encoding in one or two directions is given to a nuclear magnetic resonance signal by gradient magnetic field pulses for imaging. In the MRI apparatus, it is necessary to repeat measurement of the nuclear magnetic resonance signal in order to give phase encoding, and there is a problem that a measurement time is prolonged.
Various techniques for shortening the measurement time have been proposed, and one of them is parallel imaging in which k-space data is reduced and measured. When the k-space data is undersampled in a phase encoding direction, the aliasing (wrap-around) occurs in the image. In parallel imaging, sensitivity distribution of a plurality of receiving coils is used to eliminate aliasing of the image caused by undersampling. There are two major methods for unfolding wraparound, one is a method of unfolding aliasing by calculation of measurement domain (SMASH method, GRAPPA), and the other is a method of eliminating aliasing by calculation of an image domain (SENSE method) (Non-Patent Literature 1).
FIG. 1 is a diagram showing an overall configuration of an MRI apparatus.
FIG. 2 is an overall configuration diagram of the MRI apparatus including details of an imaging unit.
FIG. 3 is an explanatory diagram showing a relationship between phases of a captured image and a true image.
Embodiments of an MRI apparatus of the present invention will be described below with reference to the drawings.
<Configuration of Apparatus>
First, configuration of an apparatus common to the embodiments described below will be described.