Magnetic resonance imaging apparatus and magnetic resonance imaging method
A camera device, magnetic resonance technology, applied in magnetic resonance measurement, measurement using a nuclear magnetic resonance imaging system, measurement device, etc., can solve problems such as inability to suppress artifacts
Inactive Publication Date: 2005-01-26
HITACHI HEALTHCARE MFG LTD
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Therefore, when a linear or nonlinear phase error occurs in the sampling of each echo signal due to eddy currents and incompleteness of the gradient magnetic field in the readout direction, it cannot be eliminated with the same correction amount, but N / 2 false positives will occur. In image reconstruction, it is impossible to suppress the generation of artifacts
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[0021] Hereinafter, drawings used in the embodiments of the present invention will be described. figure 1 is a diagram showing the sequence of signal processing in the first embodiment, figure 2 is a block diagram showing the overall configuration of a magnetic resonance imaging apparatus, image 3 It is a figure which shows the imaging sequence of the original measurement of 1st Example. Figure 4 It is a figure which shows the imaging sequence of the reference measurement of 1st Example.
[0022] Such as figure 2 As shown, the magnetic resonance imaging device is composed of the following parts: a static magnetic field generating circuit 1, a gradient magnetic field generating system 2, a transmitting system 3, a receiving system 4, a signal processing system 5, a sequence controller 6, and a central processing unit (CPU) 7 And operating part 8. The static magnetic field generating circuit 1 is a part that generates a static magnetic field in a space where the subject ...
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In a magnetic resonance imaging apparatus, in order to suppress generation of artifacts when a linear or non-linear phase error is generated during sampling of the echo signals, a first sequence for acquiring a plurality of echo signals by radiating a radio-frequency magnetic field pulse to an object to be examined, performing phase encoding, while alternating the polarity of a readout gradient magnetic field, and a second sequence for acquiring a plurality of echo signals by repeatedly applying the readout gradient magnetic field while reversing its polarity to that in the first sequence at the same phase encoding direction are performed. Signal processing means performs complex addition of the echo signals having the same phase encoding amount respectively obtained in the first sequence and the second sequence, and reconstructs an image.
Description
technical field [0001] The present invention relates to a magnetic resonance imaging device, in particular to a technology for suppressing the occurrence of artifacts produced by phase changes between echo signals. Background technique [0002] A magnetic resonance imaging device (hereinafter referred to as an MRI device) irradiates a living body with high-frequency magnetic field pulses in a state where a uniform static magnetic field acts on the living body, excites atomic nuclei such as hydrogen and phosphorus in the living body, and measures nuclear magnetic resonance signals generated by the excitation ( NMR signal) is used for medical diagnosis by imaging the measurement region in the living body based on magnetic resonance information such as the density distribution and relaxation time distribution of hydrogen and phosphorus. [0003] In the MRI apparatus, there are various methods of measuring echo signals (NMR signals) typified by spin echo (Spin echo) and gradient...
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IPC IPC(8): G01R33/48A61B5/055G01R33/54G01R33/565
CPCG01R33/565G01R33/56518G01R33/56563G01R33/56572
Inventor 熊井秀树竹内博幸
Owner HITACHI HEALTHCARE MFG LTD