US6366090B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic resonance tomography apparatus and operating method allowing multiple scans in rapid succession
Assignee: Siemens Healthcare GmbH
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Filing: 1999-12-28
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Granted: 2002-04-02
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Expires: 2019-12-28
Abstract
Abstract In a method in the form of a pulse sequence for operating a magnetic resonance tomography apparatus, and in a magnetic resonance tomography apparatus operated according to the method, image data are obtained according to a SSFP or FISP (Fast Image Steady Precession) pulse sequence. After the end of the imaging sequence, a decay radio-frequency pulse having a flip angle of approximately α/2 with a phase angle inverted relative to the last excitation pulse of the imaging sequence is emitted wherein α is the flip angle of the excitation pulses of the imaging sequence. The decay radio-frequency pulse is emitted at an interval T R /2 following the last excitation pulse, where T R is the repetition time of the imaging sequence.
Inventors
- 👤 Oliver Heid
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:51
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/54; G01R33/56; G01R33/561; G01R33/5615; G01R33/5613; G01R33/5617
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
134 words
A method for generating a magnetic resonance tomographic image, comprising the steps of: generating an imaging pulse sequence, having a repetition time T R , having a plurality of excitation pulses of ±α, including a last excitation pulse, which excite nuclear spins in an examination subject and which cause a magnetization vector of said nuclear spins to oscillate between +α/2 and −α/2, to obtain image data for a first image of said examination subject; and to prepare for an acquisition of a subsequent data set for a second image of said examination subject, generating a decay radio-frequency pulse having a flip angle of approximately α/2 and a phase angle which is inverted relative to a phase angle of said last excitation pulse, at an interval of T R /2 following said last excitation pulse.
Claim 2
Independent Claim
134 words
A method for generating a magnetic resonance tomographic image, comprising the steps of: generating an imaging pulse sequence, having a repetition time T R , having a plurality of excitation pulses of ±α, including a last excitation pulse, which excite nuclear spins in an examination subject and which cause a magnetization vector of said nuclear spins to oscillate between +α/2 and −α/2, to obtain image data for a first image of said examination subject; and to prepare for an acquisition of a subsequent data set for a second image of said examination subject, generating a decay radio-frequency pulse having a flip angle of approximately α/2 and a phase angle which is inverted relative to a phase angle of said last excitation pulse, at an interval of T R /2 following said last excitation pulse.
Claim 3
Dependent Claim
42 words
A method as claimed in claim 1 further comprising, at an end of said pulse sequence, generating a gradient pulse in a slice selection direction z having a high product t·G z , wherein t is a duration of said gradient pulse.
Claim 4
Dependent Claim
54 words
A method as claimed in claim 1 comprising emitting a further decay radio-frequency pulse having a flip angle of approximately α and a phase angle which is inverted relative to the phase angle of said decay radio-frequency pulse, after said pulse sequence and at an interval T R /2 preceding said decay radio-frequency pulse.
Claim 5
Dependent Claim
138 words
A resonance tomography apparatus comprising: a scanner operated by a controller to generate an imaging pulse sequence, having a repetition time T R , having a plurality of excitation pulses of ±α, including a last excitation pulse, which excite nuclear spins in an examination subject in said scanner and which causes a magnetization vector of said nuclear spins to oscillate between +α/2 and −α/2, to obtain image data for a first image of said examination subject; and said controller, to prepare for an acquisition of a subsequent data set for a second image of said examination subject, generating a decay radio-frequency pulse having a flip angle of approximately α/2 and a phase angle which is inverted relative to a phase angle of said last excitation pulse, at an interval of T R /2 following said last excitation pulse.
Claim 6
Dependent Claim
138 words
A resonance tomography apparatus comprising: a scanner operated by a controller to generate an imaging pulse sequence, having a repetition time T R , having a plurality of excitation pulses of ±α, including a last excitation pulse, which excite nuclear spins in an examination subject in said scanner and which causes a magnetization vector of said nuclear spins to oscillate between +α/2 and −α/2, to obtain image data for a first image of said examination subject; and said controller, to prepare for an acquisition of a subsequent data set for a second image of said examination subject, generating a decay radio-frequency pulse having a flip angle of approximately α/2 and a phase angle which is inverted relative to a phase angle of said last excitation pulse, at an interval of T R /2 following said last excitation pulse.
Claim 7
Dependent Claim
43 words
An apparatus as claimed in claim 4 wherein said controller, at an end of said pulse sequence, generates a gradient pulse in a slice selection direction z having a high product t·G z , wherein t is a duration of said gradient pulse.
Claim 8
Dependent Claim
56 words
An apparatus as claimed in claim 4 wherein said controller emits a further decay radio-frequency pulse having a flip angle of approximately α and a phase angle which is inverted relative to the phase angle of said decay radio-frequency pulse, after said pulse sequence and at an interval T R /2 preceding said decay radio-frequency pulse.
References Cited (Backward Citations)
US5541514A
Cited
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