摘要:
In the diffusion spectroscopic imaging, in which intensity of molecular diffusion is imaged with separating chemical substances, with suppressing artifacts resulting from object motion of an object, spatial resolution, spectral band and SNR are maintained, and measurement accuracy is enhanced. A measurement for acquiring diffusion SI data is repeated a plurality of times with changing acquisition timing, phase variation of each measurement result is corrected, and a diffusion SI image is reconstructed from the corrected measurement results. In addition, the phase variation is calculated for every point in the space from the diffusion SI data acquired by each measurement or navigation data obtained by each measurement. The phase correction is independently performed for every point in the space.
摘要:
An object of the present invention is to provide a measuring technique which allows in the MRS measurement to suppress with a high degree of precision, incorporation of a signal of unwanted compounds which hinders measurement of a measurement object signal, independent of an imaging object region and the measurement object signal, thereby obtaining a stable and favorable signal spectrum. In the MRS measuring sequence, a spectrum selective inversion RF pulse, having a narrow band characteristic for selectively inverting only a signal peak of a compounds to be suppressed, and phase dispersion-refocusing GC pulses are applied at least one of before and after a region selective RF pulse. This MRS measuring sequence is repeated while changing the echo time TE at predetermined intervals, and nuclear magnetic resonance signals being obtained by the repetition are integrated. The amount of the spectrum selective inversion RF pulse to be applied may be changed according to the echo time TE.
摘要:
An object of the invention is to obtain a magnetic resonance spectroscopic image to which the MAC summation is applied with high accuracy and in short time, even though a phase characteristic distribution of the MAC has a spatial non-uniformity, in the MRSI measurement using a magnetic resonance imaging apparatus provided with a MAC. Using a non-water-suppressed image signal with high SNR, obtained in the non-water-suppressed measurement (a reference measurement) without water suppression, a correction value for correcting the phase distortion for the MAC summation is calculated on each pixel in each coil. After correcting a phase on each pixel in each coil of a main-scan image signal measured under suppressing water (water-suppressed image signal) using the corrective value, signal adding operation (summation) is performed. Then, a phase correction in a spectrum-axis is to be performed on the summed spectrum signal.
摘要:
A magnetic resonance imaging system capable of conducting spectroscopic imaging with an improved SNR without degrading the spatial resolution includes edge-preserving filter processing means for spectroscopic imaging. The edge-preserving filter processing means executes processing including the steps of calculating spectral similarity in spatial neighborhoods (spatially neighboring voxels) at each voxel in spectroscopic imaging data, calculating a spectral weight according to the spectral similarity, and conducting weighted smoothing for compounding spectra of spatial neighborhoods (spatially neighboring voxels) according to the spectral weight.
摘要:
An object of the invention is to obtain a magnetic resonance spectroscopic image to which the MAC summation is applied with high accuracy and in short time, even though a phase characteristic distribution of the MAC has a spatial non-uniformity, in the MRSI measurement using a magnetic resonance imaging apparatus provided with a MAC.Using a non-water-suppressed image signal with high SNR, obtained in the non-water-suppressed measurement (a reference measurement) without water suppression, a correction value for correcting the phase distortion for the MAC summation is calculated on each pixel in each coil.After correcting a phase on each pixel in each coil of a main-scan image signal measured under suppressing water (water-suppressed image signal) using the corrective value, signal adding operation (summation) is performed.Then, a phase correction in a spectrum-axis is to be performed on the summed spectrum signal.
摘要:
Images of two or more kinds of substances showing different chemical shifts, such as water image and metabolite image, are obtained without extending measurement time. For example, images of two or more kinds of desired substances showing different chemical shifts, such as water image and metabolite image, are obtained by one time of execution of an imaging sequence. In this execution, a pre-pulse is applied so that signals of the substances to be separated shift on the image, and magnetic resonance signals are received with receiver RF coils in a number not smaller than the number of types of the substances to be separated. An image reconstructed from the magnetic resonance signals is separated into images of the individual substances using sensitivity maps of the receiver RF coils. Then, correction is performed for returning the shifted image to the original position. Further, residual signals induced by errors generated in the measurement and the separation processing are eliminated by using spectroscopic images obtained after the separation.
摘要:
In the diffusion spectroscopic imaging, in which intensity of molecular diffusion is imaged with separating chemical substances, with suppressing artifacts resulting from object motion of an object, spatial resolution, spectral band and SNR are maintained, and measurement accuracy is enhanced. A measurement for acquiring diffusion SI data is repeated a plurality of times with changing acquisition timing, phase variation of each measurement result is corrected, and a diffusion SI image is reconstructed from the corrected measurement results. In addition, the phase variation is calculated for every point in the space from the diffusion SI data acquired by each measurement or navigation data obtained by each measurement. The phase correction is independently performed for every point in the space.
摘要:
A method for obtaining the most appropriate amplitude of signal suppression pulse, which suppresses unnecessary signals from the substance not subjected to measurement, highly accurately, swiftly and stably, and an MRI apparatus that enables the optimization are provided.A pulse amplitude adjusting means equipped in the MRI apparatus acquires signals while changing the amplitude of signal suppression pulse and calculates signal absolute values and phase values, and computes reference signals, which are polarized signal absolute values, based on the changes in signal phase values. This reference signals are subjected to polynomial fitting. A value which makes this fitting curve is 0 or closes to 0 is set as the optimal pulse amplitude.
摘要:
In an inspection method which generates a static magnetic field, a gradient magnetic field and a radio frequency magnetic field, detects nuclear magnetic resonance signals from an inspection object, computes and processes the nuclear magnetic resonance signals so detected and outputs the result of computation processing, a gradient magnetic field for generating signal attenuation by diffusion and an oscillating gradient magnetic field for generating chemical shift information and spatial information of the materials contained in the inspection object are applied, separation and acquisition of spatial information of each material contained in the inspection object are simultaneously conducted, and a measurement time is shortened.
摘要:
A technique in a medical imaging apparatus being capable of setting any plane in three-dimensional space as an imaging slice is provided, allowing an automatically-set imaging slice to be configured to suit user's preferences, and determine a position of the imaging slice being configured, with respect to an imaging target subject automatically with a high degree of accuracy. Reference information for specifying the imaging slice, set by the user for each imaging site, is associated with the anatomical feature of the imaging site, so as to generate an imaging slice parameter. Upon actual imaging, the imaging slice parameter and the anatomical feature of the imaging target subject obtained by scout imaging are used to determine the imaging slice position of the imaging target subject.