US 2001/0018559 A1 · Magnetic resonance imaging method and apparatus

Abstract

A nuclear magnetic resonance imaging apparatus, comprises: a means which generates a static magnetic field, a means which generates a gradient magnetic field in three directions, a means which generates a radiofrequency magnetic field, a means which detects a nuclear magnetic resonance signal generated from the subject to be inspected, a means which detects a periodic physiological signal from the subject to be inspected, and a control means which (1) detects a physiological signal, and generates a synchronizing signalwhich initiates apulse sequence which detects a nuclear magnetic resonance signal from the physiological signal, and (2) synchronizes a radiofrequency burst pulse comprising plural sub-pulses formed at equidistant intervals on the time axis whereof the amplitudes are modulated by a sinc function, and the gradient magnetic field in one direction, with the synchronizing signal, applies them, and assigns tags by modulating the nuclear magnetization of the subject to be inspected in one direction. According to this invention, the cardiac function can be extracted to high precision in a short time.

Claims20

Dependent claims

A nuclear magnetic resonance imaging apparatus, comprising:

means which generates a static magnetic field,
gradient magnetic field generating means which generates a gradient magnetic field in three mutually perpendicular directions,
radiofrequency magnetic field generating means which generates a radiofrequency magnetic field,
signal detecting means which detects a nuclear magnetic resonance signal generated from a subject to be inspected, and
physiological signal detecting means which detects a periodic physiological signal from the subject to be inspected, and
control means which controls the gradient magnetic field generating means, radiofrequency magnetic field generating means, signal detecting means and physiological signal detecting means, wherein said control means:
(1) detects a physiological signal, and generates a synchronizing signal which initiates a pulse sequence which detects a nuclear magnetic resonance signal from the physiological signal, and
(2) synchronizes a radiofrequency burst pulse comprising plural sub-pulses formed at equidistant intervals on the time axis whereof the amplitudes are modulated by a sinc function, and the gradient magnetic field in one direction of the three directions, with the synchronizing signal, applies them, and
modulates the nuclear magnetization of the subject to be inspected in said one direction.

6 more elements

A nuclear magnetic resonance imaging apparatus, comprising:

means which generates a static magnetic field,
gradient magnetic field generating means which generates a gradient magnetic field in first, second, and third mutually perpendicular directions,
radiofrequency magnetic field generating means which generates a radiofrequency magnetic field,
signal detecting means which detects a nuclear magnetic resonance signal generated from the subject to be inspected, and
physiological signal detecting means which detects a periodic physiological signal from the subject to be inspected, and
control means which controls the gradient magnetic field generating means, radiofrequency magnetic field generating means, signal detecting means and physiological signal detecting means, wherein said control means:
(1) detects a physiological signal, and generates a synchronizing signal which initiates a pulse sequence which detects a nuclear magnetic resonance signal from the physiological signal,
(2) synchronizes a first radiofrequency burst pulse comprising plural sub-pulses formed at equidistant intervals on the time axis whereof the amplitudes are modulated by a sinc function, and the gradient magnetic field in said first direction or second direction, with the synchronizing signal, applies them, and modulates the nuclear magnetization of the subject to be inspected in said first direction or second direction,
(3) applies a second radiofrequency burst pulse comprising plural sub-pulses formed at equidistant intervals on the time axis whereof the amplitudes are modulated by a sinc function and the gradient magnetic field in said first direction to excite the nuclear magnetization of the subject to be inspected after a predetermined waiting time has elapsed following implementation of (2),
(4) applies a radiofrequency magnetic field pulse while a gradient magnetic field is applied in the third direction,
(5) assignspositionalinformation in the second direction to the nuclear magnetization due to application of the gradient magnetic field in the second direction, generates a nuclear magnetic resonance signal in which positional information in the first direction is assigned to the nuclear magnetization due to application of the gradient magnetic field in the first direction, and measures the nuclear magnetic resonance signal,
(6) repeats the steps (4) and (5) plural times, and
(7) repeats the steps from (1) to (6) plural times.

10 more elements

A nuclear magnetic resonance imaging apparatus, comprising:

means which generates a static magnetic field,
gradient magnetic field generating means which generates a gradient magnetic field in first, second and third mutually perpendicular directions,
radiofrequency magnetic field generating means which generates a radiofrequency magnetic field,
signal detecting means which detects a nuclear magnetic resonance signal generated from the subject to be inspected, and
physiological signal detecting means which detects a periodic physiological signal from the subject to be inspected, and
control means which controls the gradient magnetic field generating means, radiofrequency magnetic field generating means, signal detecting means and physiological signal detecting means, wherein said control means:
(1) detects a physiological signal, and generates a synchronizing signal which initiates a pulse sequence which detects a nuclear magnetic resonance signal from the physiological signal,
(2) synchronizes a first radiofrequency burst pulse comprising plural sub-pulses formed at equidistant intervals on the time axis whereof the amplitudes are modulated by a sinc function, and the gradientmagnetic field in said first direction, with the synchronizing signal, applies them, and modulates the nuclear magnetization of the subject to be inspected in said first direction,
(3) applies a second radiofrequency burst pulse comprising plural sub-pulses formed at equidistant intervals on the time axis whereof the amplitudes are modulated by a sinc function and the gradient magnetic field in said second direction, and modulates the nuclearmagnetizationof the subject tobe inspected in said second direction,
(4) applies a third radiofrequency burst pulse comprising plural sub-pulses formed at equidistant intervals on the time axis whereof the amplitudes are modulated by a sinc function, and the gradient magnetic field in said first direction, to excite the nuclear magnetization of the subject to be inspected after a predetermined waiting time has elapsed following implementation of (3),
(5) applies a radiofrequency magnetic field pulse while a gradient magnetic field is applied in the third direction,
(6) assigns positional information in the second direction to the nuclear magnetization due to application of the gradient magnetic field in the second direction, generates a nuclear magnetic resonance signal in which positional information in said first direction is assigned to the nuclear magnetization due to application of the gradient magnetic field in said first direction, and measures the nuclear magnetic resonance signal,
(7) repeats the steps (5) and (6) plural times, and
(8) repeats the steps (1) to (7) plural times.

11 more elements

A nuclear magnetic resonance imaging method, comprising the steps of:

(1) a step which detects a periodic physiological signal of a subject to be inspected,
(2) a step which generates a synchronizing signal which initiates a pulse sequence which detects a nuclear magnetic resonance signal from the subject to be inspected, from the physiological signal,
(3) a step which synchronizes a first radiofrequency burst pulse comprising plural sub-pulses formed at equidistant intervals on the time axis whereof the amplitudes are modulated by a sinc function, and the gradient magnetic field in said first direction or said second direction, with the synchronizing signal, applies them, and modulates the nuclear magnetization of the subject to be inspected in said first direction,
(4) a step which applies a second radiofrequency burst pulse comprising plural sub-pulses formed at equidistant intervals on the time axis whereof the amplitudes are modulated by a sinc function, and the gradient magnetic field in said second direction, with the synchronizing signal, applies them, and modulates the nuclear magnetization of the subject to be inspected in said second direction,
(5) a step which applies a third radiofrequency burst pulse comprising plural sub-pulses formed at equidistant intervals on the time axis whereof the amplitudes are modulated by a sinc function, and the gradient magnetic field in said first direction, to excite the nuclear magnetization of the subject to be inspected after a predetermined waiting time has elapsed following implementation of the step (4),
(6) a step which applies a radiofrequency magnetic field pulse while a gradient magnetic field is applied in the third direction,
(7) a step which assigns positional information in the second direction to the nuclear magnetization due to application of the gradient magnetic field in the second direction, generates a nuclear magnetic resonance signal in which positional information in said first direction is assigned to the nuclear magnetization due to application of the gradient magnetic field in said first direction, and measures the nuclear magnetic resonance signal,
(8) a step which repeats the steps (6) and (7) plural times, and
(9) a step which repeats the steps (1) to (8) plural times.

6 more elements

Dependencies are inferred from the claim text.

Magnetic resonance imaging method and apparatus

Life of this patent

Magnetic resonance imaging method and apparatus

Life of this patent

Abstract

Claims20