MAGNETIC RESONANCE SYSTEM AND METHOD TO ADJUST AT LEAST ONE SHIM CURRENT AND AN ASSOCIATED RF CENTER FREQUENCY DURING AN INTERLEAVED MULTISLICE MR MEASUREMENT OF A MOVING EXAMINATION SUBJECT
First Claim
1. A method for implementing an interleaved multislice magnetic resonance (MR) measurement of a moving examination subject, comprising:
- continuously moving an examination subject through an MR data acquisition unit;
while continuously moving the examination subject through the MR data acquisition unit, acquiring MR data from the subject in an interleaved multislice MR data acquisition procedure in which a basic magnetic field is generated in a measurement volume of the MR data acquisition unit and in which at least two successive excitations of nuclear spins in a slice of the examination subject are produced by radiation of respective RF pulses by an RF system of the MR data acquisition unit, said RF system having an RF center frequency, and acquiring MR data from said slice after said at least two successive excitations of the nuclear spins in said slice; and
shimming said basic magnetic field to achieve a desired homogeneity of said basic magnetic field at least in said measurement volume by, via a computerized control unit, adjusting a shim current in a shim channel of said MR data acquisition unit, together with adjusting said RF center frequency, in order to avoid phase discontinuities between measurement data respectively acquired from said slice after each of said at least two successive excitations.
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Accused Products
Abstract
In a method and system to adjust at least one shim current in a shim channel of a magnetic resonance apparatus and an associated RF center frequency for the radio-frequency system of the magnetic resonance apparatus during an interleaved multislice MR measurement of a moving examination subject, in which MR measurement at least two excitations are implemented for complete acquisition of the desired data of a slice of the examination subject that is to be measured, the multislice MR measurement is implemented such that phase discontinuities between measurement data acquired after individual excitations are avoided.
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Citations
9 Claims
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1. A method for implementing an interleaved multislice magnetic resonance (MR) measurement of a moving examination subject, comprising:
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continuously moving an examination subject through an MR data acquisition unit; while continuously moving the examination subject through the MR data acquisition unit, acquiring MR data from the subject in an interleaved multislice MR data acquisition procedure in which a basic magnetic field is generated in a measurement volume of the MR data acquisition unit and in which at least two successive excitations of nuclear spins in a slice of the examination subject are produced by radiation of respective RF pulses by an RF system of the MR data acquisition unit, said RF system having an RF center frequency, and acquiring MR data from said slice after said at least two successive excitations of the nuclear spins in said slice; and shimming said basic magnetic field to achieve a desired homogeneity of said basic magnetic field at least in said measurement volume by, via a computerized control unit, adjusting a shim current in a shim channel of said MR data acquisition unit, together with adjusting said RF center frequency, in order to avoid phase discontinuities between measurement data respectively acquired from said slice after each of said at least two successive excitations. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A magnetic resonance apparatus comprising:
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a magnetic resonance data acquisition unit; a patient bed operable to move an examination subject thereon continuously through a measurement volume of said MR data acquisition apparatus; said MR data acquisition apparatus comprising a radio frequency (RF) system having an RF center frequency, and a basic field magnet that generates a basic magnetic field in said measurement volume, and a shimming system comprising of at least one shim channel, a control unit configured to operate said patient bed and said MR data acquisition unit to continuously move an examination subject through an MR data acquisition unit on the patient bed and, while continuously moving the examination subject through the MR data acquisition unit, acquire MR data from the subject in an interleaved multislice MR data acquisition procedure in which a basic magnetic field is generated by said basic field magnet in a measurement volume of the MR data acquisition unit and in which at least two successive excitations of nuclear spins in a slice of the examination subject are produced by radiation of respective RF pulses by said RF system, and acquire MR data from said slice after said at least two successive excitations of the nuclear spins in said slice; and said control unit being configures to operate said shimming system to shim said basic magnetic field to achieve a desired homogeneity of said basic magnetic field at least in said measurement volume by, via a computerized control unit, adjusting a shim current in said at least one shim channel together with adjusting said RF center frequency, in order to avoid phase discontinuities between measurement data respectively acquired from said slice after each of said at least two successive excitations.
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9. A non-transitory, computer-readable data storage medium encoded with programming instructions that, when said data storage medium is loaded into a computerized control unit of a magnetic resonance apparatus, that comprises a magnetic resonance data acquisition unit with a patient bed configured to continuously move an examination subject thereon through the MR data acquisition unit, a radio-frequency (RF) system having an RF center frequency, and a basic field magnet that generates a basic magnetic field in a measurement volume in said MR data acquisition unit, and a shimming system comprising at least one shim channel, and said programming instructions causing said computerized control system to:
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continuously moving an examination subject through an MR data acquisition unit on the patient bed; while continuously moving the examination subject through the MR data acquisition unit, acquire MR data from the subject in an interleaved multislice MR data acquisition procedure in which a basic magnetic field is generated by said basic field magnet in a measurement volume of the MR data acquisition unit and in which at least two successive excitations of nuclear spins in a slice of the examination subject are produced by radiation of respective RF pulses by said RF system, and acquire MR data from said slice after said at least two successive excitations of the nuclear spins in said slice; and shim said basic magnetic field to achieve a desired homogeneity of said basic magnetic field at least in said measurement volume by adjusting a shim current in said at least one shim channel together with adjusting said RF center frequency, in order to avoid phase discontinuities between measurement data respectively acquired from said slice after each of said at least two successive excitations.
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Specification