摘要:
A magnetic resonance imaging (MRI) system obtains an MR image of an object. The system detects an ECG signal and performs a pulse sequence of RF gradient magnetic fields toward the object. Imaging defined by the pulse sequence is longer in temporal length than one heartbeat. The system further acquires an MR signal from the object in response to performance of the pulse sequence and produces the MR image based on the acquired MR signal. Also possible are: a plurality of divided MT pulses instead of the conventional single MT pulse, an SE-system pulse sequence having a shorter echo train spacing, and the generation of sounds by applying gradient pulses incorporated in an imaging pulse sequence so as to automatically instruct a patient to perform an intermittent breath hold.
摘要:
A magnetic resonance imaging apparatus includes an RF coil unit which generates RF pulses toward a subject, and which receives an MR signal from the subject. Gradient magnetic field coils generate a gradient magnetic field for slice selection, a gradient magnetic field for phase encoding and a gradient magnetic field for frequency encoding, respectively. An arithmetic unit generates image data on the basis of the MR signal, and a sequence controller controls phase encoding gradient magnetic field coils in order to generate flow pulses for dephasing or rephasing the MR spin of blood flow within the subject, in the same direction as that of the phase encoding gradient magnetic field.
摘要:
An artery vein visually separated MRA image and/or a higher blood/parenchyma contrast MRA image are provided by a magnetic resonance imaging system. The system comprises, in addition to a magnet generating a static magnetic field, a gradient generation unit generating magnetic gradients superimposed on the static magnetic field, a transmission/reception unit transmitting to a subject spin-exciting RF signal and receiving an MR signal emanated from the subject, a reconstruction unit reconstructing the image based on the MR, and a sequencer for performing a scan sequence of pulses through control of the gradient generation unit and the transmission/reception unit. The scan sequence of pulses is formed for producing the functions of: applying not only a plurality of saturation pulses in time series to a pre-saturated slice positionally different from the imaging slice but also a slice gradient pulse for selecting the pre-saturated slice concurrently with the plurality of saturation pulses, and performing a data acquisition sequence applying to the imaging slice a pulse train for acquiring an MR signal from the imaging slice after application of the plurality of saturation pulses and the slice gradient pulse.
摘要:
A magnetic resonance imaging apparatus includes the data gathering unit gathers magnetic resonance data in a non-contrast manner by applying a first readout gradient pulse having a zero-order moment of 0 and second readout gradient pulse having a zero-order moment of 0 and a first-order moment of a value different from a value of a first-order moment of the first readout gradient pulse to a region of interest including a fluid in motion, and periodically arranging first magnetic resonance data readout with the first readout gradient pulse and second magnetic resonance data read out with the second readout gradient pulse in at least one of a phase encoding direction and a slice encoding direction in a k-space to generate k-space data and reconstructs the k-space data to generate an image in which a fluid image and static part image surrounding the fluid are spatially separated from each other.
摘要:
A magnetic resonance imaging apparatus includes a first blood flow image acquisition unit and a second blood flow image acquisition unit. The first blood flow image acquisition unit acquires a first blood flow image of a breast of an object without contrast medium. The second blood flow image acquisition unit acquires a second blood flow image without contrast medium with applying a spin labeling pulse by which a region to be tagged is set based on the first blood flow image as a reference image so as to distinguish blood flowing into a desired region.
摘要:
A magnetic resonance imaging (MRI) system obtains an MR image of an object. The system detects an ECG signal and performs a pulse sequence of RF gradient magnetic fields toward the object. Imaging defined by the pulse sequence is longer in temporal length than one heartbeat. The system further acquires an MR signal from the object in response to performance of the pulse sequence and produces the MR image based on the acquired MR signal. Also possible are: a plurality of divided MT pulses instead of the conventional single MT pulse, an SE-system pulse sequence having a shorter echo train spacing, and the generation of sounds by applying gradient pulses incorporated in an imaging pulse sequence so as to automatically instruct a patient to perform an intermittent breath hold.
摘要:
A magnetic resonance imaging (MRI) system includes an ECG detector for the patient object being imaged and an element for performing an MRI pulse sequence. An imaging unit defined by the pulse sequence is longer in temporal length than one heart beat represented by the ECG signal. An MR signal is acquired from the object in response to the pulse sequence and an MR image based on the acquired MR signal is produced. A plurality of divided MT pulses can be applied instead of the conventional single MT pulse. In this case, an SE-system pulse sequence having a shorter echo train spacing is used, to generate sounds by applying gradient pulses incorporated in an imaging pulse sequence so as to automatically instruct a patient to perform an intermittent breath hold during three-dimensional scanning.
摘要:
A magnetic resonance imaging apparatus according to an embodiment includes a data gathering unit and an image generating unit, the data gathering unit gathers magnetic resonance data in a non-contrast manner by applying a first readout gradient pulse having a zero-order moment of 0 and a second readout gradient pulse having a zero-order moment of 0 and a first-order moment of a value different from a value of a first-order moment of the first readout gradient pulse to a region of interest including a fluid in motion, and the image generating unit periodically arranges first magnetic resonance data read out with the first readout gradient pulse and second magnetic resonance data read out with the second readout gradient pulse in at least one of a phase encoding direction and a slice encoding direction in a k-space to generate k-space data and reconstructs the k-space data to generate an image in which a fluid image and a static part image surrounding the fluid are spatially separated from each other.
摘要:
A magnetic resonance imaging (MRI) system includes an ECG detector for the patient object being imaged and an element for performing an MRI pulse sequence. An imaging unit defined by the pulse sequence is longer in temporal length than one heart beat represented by the ECG signal. An MR signal is acquired from the object in response to the pulse sequence and an MR image based on the acquired MR signal is produced. A plurality of divided MT pulses can be applied instead of the conventional single MT pulse. In this case, an SE-system pulse sequence having a shorter echo train spacing is used, to generate sounds by applying gradient pulses incorporated in an imaging pulse sequence so as to automatically instruct a patient to perform an intermittent breath hold during three-dimensional scanning.
摘要:
An ECU-prep scan is used to set an optimum time phase in both systole and diastole of the heart. At each of the different time phases, an imaging scan is started to acquire a plurality of sets of echo data. An artery/vein visually separated blood flow image is produced from the echo data. The imaging scan uses a half-Fourier technique, for example. This provides high-quality blood flow images with shorter scan time, without injecting a contrast medium. Additionally, with a readout gradient pulse applied substantially parallel with a direction of slowly flowing blood, a scan is performed in synchronism with an optimally determined cardiac time phase. The readout gradient pulse has a dephasing pulse for enhancing differences in a flow void effect depending on blood flow velocities. This enables slow-speed flows, such as blood flows in the inferior limb, to be depicted without fail.