Magnetic resonance apparatus and method for vascular imaging
First Claim
1. A method for vascular imaging using a magnetic resonance (MR) apparatus comprising:
- using a computer to operate an MR data acquisition scanner, while an examination subject is situated therein, in order to apply a magnetic field to an imaging volume and to an inflow volume, from which liquid enters into the imaging volume of the examination subject;
using said computer to operate said MR data acquisition scanner in order to radiate a radio-frequency (RF) pulse that excites nuclear spins in said imaging volume while the magnetic field is being applied;
in said computer, generating control signals in order to radiate said RF pulse so as to fulfill a magnetization transfer function and a fat saturation function, giving said RF pulse a frequency distribution comprising frequencies that are higher than a center frequency of water in the imaging volume and said frequencies comprising the fat frequency in the imaging volume;
in said computer, generating control signals in order to apply said magnetic field with a magnetic field distribution approximated by a function that has an apex with substantially no gradient in said imaging volume and that has a higher spatial gradient in said inflow volume;
using said computer to operate said MR data acquisition scanner in order to acquire MR signals from the excited nuclear spins in the imaging volume that represent vessels in said imaging volume; and
in said computer, transforming data represented by MR signals into image data and presenting said image data at a display screen in communication with said computer in order to visualize said vessels.
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Accused Products
Abstract
In a magnetic resonance method and apparatus for time-of-flight vascular imaging, a magnetic field is applied to an imaging volume and an inflow volume, from which liquid enters into the imaging volume, of an examination person. The imaging volume is excited by an RF pulse, which fulfills a magnetization transfer function and a fat saturation function, while the magnetic field is being applied. The RF pulse has a frequency distribution whose frequencies are higher than the center frequency of water in the imaging volume, and that includes the fat frequency in the imaging volume. The magnetic field has a field distribution with an apex with essentially no spatial gradient in the imaging volume and having a higher spatial gradient in the inflow volume, so that the center frequency of water in the inflow volume is shifted in the direction of lower frequencies and is no longer affected by the RF pulse.
17 Citations
16 Claims
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1. A method for vascular imaging using a magnetic resonance (MR) apparatus comprising:
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using a computer to operate an MR data acquisition scanner, while an examination subject is situated therein, in order to apply a magnetic field to an imaging volume and to an inflow volume, from which liquid enters into the imaging volume of the examination subject; using said computer to operate said MR data acquisition scanner in order to radiate a radio-frequency (RF) pulse that excites nuclear spins in said imaging volume while the magnetic field is being applied; in said computer, generating control signals in order to radiate said RF pulse so as to fulfill a magnetization transfer function and a fat saturation function, giving said RF pulse a frequency distribution comprising frequencies that are higher than a center frequency of water in the imaging volume and said frequencies comprising the fat frequency in the imaging volume; in said computer, generating control signals in order to apply said magnetic field with a magnetic field distribution approximated by a function that has an apex with substantially no gradient in said imaging volume and that has a higher spatial gradient in said inflow volume; using said computer to operate said MR data acquisition scanner in order to acquire MR signals from the excited nuclear spins in the imaging volume that represent vessels in said imaging volume; and in said computer, transforming data represented by MR signals into image data and presenting said image data at a display screen in communication with said computer in order to visualize said vessels. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A magnetic resonance (MR) apparatus comprising:
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an MR data acquisition scanner comprising a basic field magnet and a radio-frequency (RF) radiator; a computer configured to operate said MR data acquisition scanner, while an examination subject is situated therein, in order to apply a magnetic field with said basic field magnet to an imaging volume and to an inflow volume, from which liquid enters into the imaging volume of the examination subject; said computer being configured to operate said MR data acquisition scanner in order to radiate a radio-frequency (RF) pulse from said RF radiator that excites nuclear spins in said imaging volume while the magnetic field is being applied; said computer being configured to generate control signals to said Rf radiator in order to radiate said RF pulse so as to fulfill a magnetization transfer function and a fat saturation function, giving said RF pulse a frequency distribution comprising frequencies that are higher than a center frequency of water in the imaging volume and said frequencies comprising the fat frequency in the imaging volume; said computer being configured to generate control signals to said basic filed magnet in order to apply said magnetic field with a magnetic field distribution approximated by a function that has an apex with substantially no gradient in said imaging volume and that has a higher spatial gradient in said inflow volume; said computer being configured to operate said MR data acquisition scanner in order to acquire MR signals from the excited nuclear spins in the imaging volume that represent vessels in said imaging volume; and said computer being configured to transform data represented by MR signals into image data and to present said image data at a display screen in communication with said computer in order to visualize said vessels.
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16. A non-transitory, computer-readable data storage medium encoded with programming instructions, said storage medium being loaded into a computer of a magnetic resonance (MR) apparatus that comprises an MR data acquisition scanner, said programming instructions causing said computer system to:
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operate said MR data acquisition scanner, while an examination subject is situated therein, in order to apply a magnetic field to an imaging volume and to an inflow volume, from which liquid enters into the imaging volume of the examination subject; operate said MR data acquisition scanner in order to radiate a radio-frequency (RF) pulse that excites nuclear spins in said imaging volume while the magnetic field is being applied; generate control signals in order to radiate said RF pulse so as to fulfill a magnetization transfer function and a fat saturation function, giving said RF pulse a frequency distribution comprising frequencies that are higher than a center frequency of water in the imaging volume and said frequencies comprising the fat frequency in the imaging volume; generate control signals in order to apply said magnetic field with a magnetic field distribution approximated by a function that has an apex with substantially no gradient in said imaging volume and that has a higher spatial gradient in said inflow volume; operate said MR data acquisition scanner in order to acquire MR signals from the excited nuclear spins in the imaging volume that represent vessels in said imaging volume; and transform data represented by MR signals into image data and present said image data at a display screen in communication with said computer in order to visualize said vessels.
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Specification