摘要:
The present invention provides a vertical magnetic field MRI apparatus which is capable of speeding up imaging for taking an image of any cross section of a wide area such as a total body, while suppressing increase of the number of channels and maintaining high sensitivity in a deep portion of a subject. A receiver coil unit 500 incorporates a bed coil unit 600 whose longitudinal direction agrees with a body axis direction of the test object 103, and an upper coil unit 700 which is detachably mounted on the bed coil unit 600. The bed coil unit 600 is provided with a carrying surface 601 for placing the test object 103 thereon and multiple lower sub-coils arranged in a lower part of the carrying surface 601, and the upper coil unit 700 is provided with multiple upper sub-coils which are connected to the lower sub-coils. The upper sub-coils are separated into two parts; one arranged in a flexible inner support 20-1 covering the installation surface 601 and another arranged in a flexible outer support 20-2 covering the external side of the inner support 20-1. The upper sub-coils and the lower sub-coils are connected by mounting the upper coil unit 700 on the bed coil unit 600, thereby forming the multiple types of sub-coils.
摘要:
The present invention provides a magnetic resonance imaging system capable of performing spectrum measurement even when a magnetic resonant frequency changes during MRS measurement. A time-varying rate of a water magnetic resonant frequency is measured in advance before the MRS measurement. The amount of change in water magnetic resonant frequency during the MRS measurement is predicted from the measured time-varying rate. With the predicted value as the reference, a transmission frequency of an RF magnetic field irradiated in a signal suppression pulse sequence, a transmission frequency of an RF magnetic field for excitation and inversion and a received frequency at the detection of a magnetic resonance signal in a sequence of the MRS measurement are respectively set. A high-precision spectrum measurement is hence enabled.
摘要:
Provided is a magnetic resonance imager capable of efficiently suppressing artifacts in radial scanning that is short of the number of echoes.Part of unmeasured echoes is measured as a reference echo. An estimation coefficient is calculated using echoes adjoining the reference echo, and used to estimate the unmeasured echoes.
摘要:
A configuration of an NMR apparatus is provided. In the NMR apparatus, a magnetic field space of higher uniformity is generated by split superconducting magnets. At the same time, it is provided with a cryo probe excellent in cooling capability and sensitivity between two superconducting solenoid coils constructed in very close proximity to each other. For this purpose, a probe coil provided between the two superconducting solenoid coils is so constructed that the following is implemented: a certain distance is ensured between a substrate with a coil formed thereon and another, and the substrates and spacer substrates for cooling are alternately laminated. The spacer substrates are cooled by a cold head of sapphire. When the probe coil is inserted in the same direction as a sample tube (direction perpendicular to the static magnetic field), the spacer substrates cannot be coupled directly by the cold head of sapphire. Therefore, they are cooled through a fixed substrate for thermal conduction of sapphire coupled with the cold head.
摘要:
In the inspection system using nuclear magnetic resonance comprising magnetic field generators such as a static magnetic field, a gradient magnetic field, and an RF magnetic field, an RF probe for detecting an NMR signal from a subject, and a calculator for operating a detected signal by the RF probe, a RF probe for detection comprises a plurality of coils arranged in the predetermined direction and includes a plurality of switching elements and the inspection system selects two or more coils from the plurality of coils for each measurement of NMR signals, turns the switching elements connected to the selected coils ON, turns the switching elements connected to coils other than the selected coils OFF, changes a combination of two or more coils for each measurement of NMR signals, and changes the sensitivity distribution of the RF probe in the predetermined direction according to the Wavelet basis function for each measurement of NMR signals.
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 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 MRI apparatus capable of selecting an optional direction as a phase encoding direction and achieving a preferable S/N, when an imaging time shortening technique is applied. A receiver coil, used as a receiver coil of a vertical magnetic field MRI apparatus, is a combination of a first coil (solenoid coil) forming a current loop around the outer circumference of a test object, second coils forming even-numbered current loops, and third coils forming odd-numbered current loops, in the direction intersecting the plane of the current loop of the first coil. The second coil and the third coil are arranged in such a manner that, as for the current loops in the array direction thereof, a position where a sensitivity of one coil is minimized approximately coincides with a position where the sensitivity of the other coil is maximized, whereby electromagnetic coupling is suppressed.
摘要:
Provided is a magnetic resonance imager capable of efficiently suppressing artifacts in radial scanning that is short of the number of echoes. Part of unmeasured echoes is measured as a reference echo. An estimation coefficient is calculated using echoes adjoining the reference echo, and used to estimate the unmeasured echoes.
摘要:
Provided is a magnetic resonance imaging apparatus capable of highly precisely detecting and compensating body motions within a short processing time during radial scanning. The magnetic resonance imaging apparatus includes a control unit that applies radiofrequency magnetic fields and magnetic field gradients to a subject lying down in a static magnetic field and that detects magnetic resonance signals generated from the subject, and an arithmetic unit that handles the signals. The arithmetic unit performs subject's body motion detection in an image space, uses an image, which is reconstructed using the low-frequency portion of the k-space data of the image, as criterial data, produces templates by moving the criterial data in advance by predetermined magnitudes of rotations and predetermined magnitudes of translations, and uses the produced templates to perform the body motion detection.