Method and apparatus for capturing magnetic resonance signals, recording medium and system for magnetic resonance imaging using the same
AssigneeGE Medical Systems Global Technology Company, LLC
InventorAki Yamazaki
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Abstract
The present invention provides selective excitation of a slab by RF signals of frequency compensated for in response to the error in the gradient magnetic field in the slice axis direction and phase encoding in the slice axis direction with the phase compensated for corresponding to the corrected frequency, in order to capture appropriate magnetic resonance signals in three dimensional scanning when there is an error in the slice gradient.
Claims19
A method of capturing magnetic resonance signals, said method comprising the steps of:
- using a three dimensional scanning by selectively exciting a slab with a gradient magnetic field and RF signals applied in a slice axis, said RF signals having a frequency compensated for in response to an error of said gradient magnetic field;
- and
- phase encoding in said slice axis in a compensated phase corresponding to said frequency compensation;
- wherein
- said compensated phase is given by the following:
- P ′ = ( 1 - 2 Δ z S ) P
- wherein:
- P′ is the phase after compensation;
- Δz is the apparent positional displacement of slab caused by frequency compensation;
- S is the slab thickness;
- and P is the phase before compensation.
An apparatus for capturing magnetic resonance signals, said apparatus comprising:
- means for using a three dimensional scanning by selectively exciting a slab with a gradient magnetic field and RF signals applied in a slice axis, said RF signals having a frequency compensated for in response to an error of said gradient magnetic field;
- and
- means for phase encoding in said slice axis in a compensated phase corresponding to said frequency compensation;
- wherein
- said compensated phase it given by the following:
- P ′ = ( 1 - 2 Δ z S ) P
- wherein:
- P′ is the phase after compensation;
- Δz to the apparent positional displacement of slab caused by frequency compensation;
- S is the slab thickness;
- and P is the phase before compensation.
A computer-readable recording medium for storing a program to be executed on a computer, said program comprising the steps of:
- using a three dimensional scanning by selectively exciting a slab with a gradient magnetic field and RF signals applied in a slice axis, said RF signals having a frequency compensated for in response to an error of said gradient magnetic field;
- and
- phase encoding in said slice axis in a compensated phase corresponding to said frequency compensation;
- wherein
- said compensated phase is given by the following:
- P ′ = ( 1 - 2 Δ z S ) P
- wherein:
- P′ to the phase after compensation;
- Δz is the apparent positional displacement of slab caused by frequency compensation;
- S to the slab thickness;
- and P is the phase before compensation.
A magnetic resonance imaging system for capturing magnetic resonance imaging signals, said system comprising:
- means for using a three dimensional scanning by selectively exciting a slab with a gradient magnetic field and RF signals applied in a slice axis, said RF signals having a frequency compensated for in response to an error of said gradient magnetic field;
- and
- means for phase encoding in said slice axis in a compensated phase corresponding to said frequency compensations;
- wherein
- said compensated phase is given by the following:
- P ′ = ( 1 - 2 Δ z S ) P
- wherein:
- P′ is the phase after compensation;
- Δz is the apparent positional displacement of slab caused by frequency compensation;
- S is the slab thickness;
- and P is the phase before compensation.
Dependencies are inferred from the claim text.