Toshiba Medical Systems Corporation

Kabushiki Kaisha Toshiba

Canon Medical Systems Corporation

Masashi Ookawa

Hitoshi Kanazawa

Kazuyuki Soejima

Shinichi Kitane

Kiyomi Ooshima

Kazuhiro Sueoka

Hidetaka Konta

Kentarou Furuhata

In one embodiment, an MRI apparatus includes a gradient coil, a receiving circuit, and processing circuitry. The gradient coil is configured to superimpose a gradient magnetic field on a static magnetic field. The receiving circuit is configured to receive an MR (magnetic resonance) signal from an object placed in the gradient magnetic field. The processing circuitry is configured to estimate time variation of an MR (magnetic resonance) frequency during a sampling period of the MR signal based on waveform data of a gradient current applied to the gradient coil, perform correction on a frequency or phase of the MR signal received by the receiving circuit based on the estimated time variation of the MR frequency during the sampling period, and reconstruct an image by using the MR signal subjected to the correction.

MRI apparatus

In one embodiment, an MRI apparatus includes: a scanner equipped with at least a static magnetic field magnet, a gradient coil, and an RF coil configured to apply RF pulses to an object and receive magnetic resonance signals from the object; and processing circuitry configured to set a pulse sequence in which refocusing pulses are sequentially applied subsequent to application of one excitation pulse and a predetermined number of magnetic resonance signals are acquired in each period between adjacent two refocusing pulses by using a water/fat separation method, such that the magnetic resonance signals are different in echo time TE for each of the plurality of refocusing pulses, cause the scanner to acquire the magnetic resonance signals under the pulse sequence, and generate a computed image from the magnetic resonance signals, the computed image being a magnetic resonance image of the object obtained by computation.

MRI apparatus and image processing apparatus

In one embodiment, an MRI apparatus () includes a reference scan setting unit (), a reference scan execution unit, and an image generation unit. The reference scan setting unit calculates a signal acquisition region of 'a reference scan in which MR signals used for generation of a sensitivity distribution map of each coil element are acquired', depending on an imaging region of a main scan of parallel imaging. The reference scan execution unit executes the reference scan on the calculated signal acquisition region. The image generation unit generates image data according to 'MR signals acquired by the main scan' and 'the sensitivity distribution map generated based on MR signals acquired by the reference scan'.

Magnetic resonance imaging apparatus and magnetic resonance imaging method

In one embodiment, an MRI apparatus includes a gradient generation circuit configured to apply a gradient pulse according to a pulse sequence in which application of an RF pulse and application of the gradient pulse are included; and an RF transmission circuit configured to (a) perform modulation on a controlled output waveform of the RF pulse in such a manner that the controlled output waveform of the RF pulse follows time variation of a magnetic resonance frequency caused by time variation of an eddy-current magnetic field estimated from a waveform of the gradient pulse and (b) apply the RF pulse subjected to the modulation to an object.

Magnetic resonance imaging apparatus

Magnetic resonance imaging (MRI) is configured to carry out sequential imaging, to acquire an actual SAR measurement value at a predetermined timing during the sequential imaging, and to update a subsequent predicted SAE value each time the actual SAR measurement value is acquired.

MRI with automatic adjustment of imaging conditions to not exceed SAR and SAE limits

A magnetic resonance imaging apparatus according to an embodiment includes a processor and a memory. The memory stores processor-executable instructions that, when executed by the processor, cause the processor to receive an operation of setting an application condition concerning a local excitation pulse that is a radio frequency (RF) pulse for local excitation applied to a local region different from an imaging region; generate a waveform of the local excitation pulse based on the application condition; and set an imaging condition such that an index value calculated from the waveform of the local excitation pulse does not exceed a limit value.

A magnetic resonance imaging apparatus of an embodiment includes: an imaging condition setting section configured to set an imaging condition for a main scan, a preparatory scan performing section configured to repeat a preparatory scan to be performed by the use of the imaging condition for a main scan and a changeably inputted center frequency so as to generate a preparatory image in real time, a display section on which the preparatory image can be displayed in real time, an optimum center frequency setting section configured to change the center frequency so as to change a situation in which a banding artifact appears and configured to set an optimum center frequency according to a user operation based on an observation of the preparatory image, and a main scan performing section configured to reconstruct an image for a diagnosis by using the optimum center frequency having been set.

In one embodiment, an MRI apparatus () includes a gap calculating unit (), a candidate calculating unit () and a sequence setting unit (). The gap calculating unit calculates a gap between the center frequency of an RF pulse and a resonance center frequency, after start of a pulse sequence. The candidate calculating unit calculates a plurality of candidate timings so as to avoid influence of a CF scan for measuring the resonance center frequency on MR signals, when the CF scan is inserted in the pulse sequence. The sequence setting unit sets the pulse sequence so that CF scans are inserted in the pulse sequence at the timings according to the gap and the candidate timings. Each time the CF scan is executed, the center frequency of an RF pulse is updated and the pulse sequence is continued. Thereby, the MR signals are acquired.

A magnetic resonance imaging apparatus according to an embodiment includes a sequence control unit that controls a gradient magnetic field power supply, thereby performing a pulse sequence including the application of a continuous readout gradient magnetic field pulse. The sequence control unit controls the gradient magnetic field power supply such that the slew rate of the gradient magnetic field pulse is reduced in stages as the output voltage of a gradient magnetic field amplifier is reduced in stages.

Magnetic resonance imaging apparatus having continuous readout gradient with gradient slew rate changed

The temperature of an MRI gradient magnetic field coil unit is measured at least two times. Shift data indicating a center magnetic resonance frequency of a hydrogen atom in response to variation of the gradient coil temperature is stored in advance. Estimated shift of the center frequency based on the measurement result is determined and the center frequency of an RF NMR excitation pulse is corrected based on the estimated shift.

According to one embodiment, an MRI apparatus performs magnetic resonance imaging under a gradient magnetic field by providing a gradient magnetic field generation system with electric current so as to apply the gradient magnetic field on an imaging region. This MRI apparatus includes a condition setting unit and a load acquisition unit. The condition setting unit sets imaging conditions of the magnetic resonance imaging. The load acquisition unit acquires information on a waveform of the gradient magnetic field, and calculates respective electric loads for a plurality of frequency bands imposed on the gradient magnetic field generation system in a case of performance of the magnetic resonance imaging, based on the information on a waveform.

Magnetic resonance imaging apparatus and load calculation method of a gradient magnetic field generation system

A magnetic resonance imaging apparatus includes a data acquisition unit and an image generating unit. The data acquisition unit acquires echo signals by echo planar imaging which generates the echo signals by applying plural phase-encoding gradient magnetic field pulses and by repeatedly inverting a readout gradient magnetic field after one nuclear magnetic resonance (NMR) excitation. Each of the plural phase-encoding gradient magnetic field pulses has an intensity set so as to compensate an influence of spatially distributed eddy currents to each of the spatial imaging positions. The image generating unit generates MRI data and an image based on the acquired echo signals.

An MRI apparatus has a waveform setting unit, an applying control unit, a reconstructing unit, and a display control unit. The waveform setting unit sets an asymmetric RF pulse Waveform. The applying control unit controls an application of a pulse in accordance with the RF pulse waveform. The reconstructing unit reconstructs an image based on a signal received by the application. The display control unit controls a display of the image.

MRI apparatus generating deformed binomial pulse waveforms based on flip angle

A real-time system changes a combination of coil elements and channel assignations for each echo by using a pulse sequence, and collects data without performing phase encoding. A host system then calculates a correlation value of data reconstructed for each channel and reference data. When the correlation value is smaller than a predetermined threshold value, the host system judges the coil element combination to be abnormal. The host system makes a level correction on the collected data and creates an alternative solution for the abnormal coil element combination, including a reduction of a number of channels.

System, method and apparatus for identifying abnormality in MRI RF input circuits by combination mode switching in single MRI sequence scan

A magnetic resonance imaging apparatus includes a data acquisition unit, a frequency offset acquisition unit, a frequency modulation unit and a phase shift correction unit. The data acquisition unit acquires pieces of echo data due to nuclear magnetic resonance after applying an excitation pulse. The frequency offset acquisition unit acquires a frequency offset. The frequency modulation unit frequency-modulates the excitation pulse according to the frequency offset. The phase shift correction unit cancels a phase shift occurring on each of the pieces of the echo data due to a frequency modulation according to the frequency offset during a readout of the pieces of the echo data.

Growing community of inventors

Otawara, Japan

Masashi Ookawa