IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Based Design and Simulation Tool forMRI Birdcage Coils Including Eigenfrequency
Analysis
Necip Gurler and Yusuf Ziya Ider
Electrical and Electronics Engineering DepartmentBilkent University, Ankara, TURKEY
11.10.2012Milan, Italy
Necip Gurler COMSOL CONFERENCE EUROPE 2012
Excerpt from the Proceedings of the 2012 COMSOL Conference in Milan
IntroductionMotivation
MethodsExperimental Results
Conclusion
Outline1 Introduction
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
2 MotivationReview of previous studiesProblem definitionOur work
3 MethodsFEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
4 Experimental Results5 Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Outline1 Introduction
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
2 MotivationReview of previous studiesProblem definitionOur work
3 MethodsFEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
4 Experimental Results5 Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Outline1 Introduction
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
2 MotivationReview of previous studiesProblem definitionOur work
3 MethodsFEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
4 Experimental Results5 Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
What Do the RF Coils Serve in MRI?
generate RF magnetic field (B1 field) at the Larmorfrequencyreceive RF signals at the same frequency
Source of figures: http://www.cis.rit.edu/htbooks/mri/chap-9/chap-9.htm
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
RF Birdcage Head Coil Example
Source of figure: http://www.healthcare.philips.com
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Outline1 Introduction
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
2 MotivationReview of previous studiesProblem definitionOur work
3 MethodsFEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
4 Experimental Results5 Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
RF Birdcage Coils
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
RF Birdcage Coils
based on the lumped element delay line (Hayes et al., 1985)
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
RF Birdcage Coils
based on the lumped element delay line (Hayes et al., 1985)
widely used in MRI
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
RF Birdcage Coils
based on the lumped element delay line (Hayes et al., 1985)
widely used in MRI
Advantages
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
RF Birdcage Coils
based on the lumped element delay line (Hayes et al., 1985)
widely used in MRI
Advantages
very homogeneous RF magnetic field
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
RF Birdcage Coils
based on the lumped element delay line (Hayes et al., 1985)
widely used in MRI
Advantages
very homogeneous RF magnetic field
high signal-to-noise ratio (SNR)
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
RF Birdcage Coils
based on the lumped element delay line (Hayes et al., 1985)
widely used in MRI
Advantages
very homogeneous RF magnetic field
high signal-to-noise ratio (SNR)
quadrature excitation and reception capability
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Birdcage Coils Consist of...
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Birdcage Coils Consist of...
two circular end rings connected by N equally spacedrungs (or legs)
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Birdcage Coils Consist of...
two circular end rings connected by N equally spacedrungs (or legs)
capacitors on the rungs or end rings or both
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Resonance Behavior of Birdcage Coils
A birdcage coil with N number of rungs andequal valued capacitors has
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Resonance Behavior of Birdcage Coils
A birdcage coil with N number of rungs andequal valued capacitors has
N/2 resonant modes (m=1,2... N/2)
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Resonance Behavior of Birdcage Coils
A birdcage coil with N number of rungs andequal valued capacitors has
N/2 resonant modes (m=1,2... N/2)
degenerate mode pairs - two modes with the samefrequency
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Resonance Behavior of Birdcage Coils
A birdcage coil with N number of rungs andequal valued capacitors has
N/2 resonant modes (m=1,2... N/2)
degenerate mode pairs - two modes with the samefrequency
end ring resonant mode (m=0)
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Resonance Behavior of Birdcage Coils
A birdcage coil with N number of rungs andequal valued capacitors has
N/2 resonant modes (m=1,2... N/2)
degenerate mode pairs - two modes with the samefrequency
end ring resonant mode (m=0)currents only flow in the end rings - Helmholtz pair
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Which Resonant Mode is used in MRI?
most homogeneous B1 field
sinusoidal current distribution in the rungs for m = 1 mode
Source of figure: M. Lupu, MAGMA, 2004, 17, 363-371
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Which Resonant Mode is used in MRI?
most homogeneous B1 field
sinusoidal current distribution in the rungs for m = 1 mode
Source of figure: M. Lupu, MAGMA, 2004, 17, 363-371
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Which Resonant Mode is used in MRI?
most homogeneous B1 field
sinusoidal current distribution in the rungs for m = 1 mode
Source of figure: M. Lupu, MAGMA, 2004, 17, 363-371
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Outline1 Introduction
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
2 MotivationReview of previous studiesProblem definitionOur work
3 MethodsFEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
4 Experimental Results5 Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Designing a RF Birdcage Coil
In order to generate a homogeneous B1 field at the desiredfrequency;
use the correct capacitance valuecalculate an initial capacitance valuetuning and matching procedures
knowing resonant modes of the birdcage coiltuning and matching procedures can be done withoutinterfering with the other modesm=0 mode is used in open MRI systems
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Designing a RF Birdcage Coil
In order to generate a homogeneous B1 field at the desiredfrequency;
use the correct capacitance valuecalculate an initial capacitance valuetuning and matching procedures
knowing resonant modes of the birdcage coiltuning and matching procedures can be done withoutinterfering with the other modesm=0 mode is used in open MRI systems
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Designing a RF Birdcage Coil
In order to generate a homogeneous B1 field at the desiredfrequency;
use the correct capacitance valuecalculate an initial capacitance valuetuning and matching procedures
knowing resonant modes of the birdcage coiltuning and matching procedures can be done withoutinterfering with the other modesm=0 mode is used in open MRI systems
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Designing a RF Birdcage Coil
In order to generate a homogeneous B1 field at the desiredfrequency;
use the correct capacitance valuecalculate an initial capacitance valuetuning and matching procedures
knowing resonant modes of the birdcage coiltuning and matching procedures can be done withoutinterfering with the other modesm=0 mode is used in open MRI systems
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Designing a RF Birdcage Coil
In order to generate a homogeneous B1 field at the desiredfrequency;
use the correct capacitance valuecalculate an initial capacitance valuetuning and matching procedures
knowing resonant modes of the birdcage coiltuning and matching procedures can be done withoutinterfering with the other modesm=0 mode is used in open MRI systems
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Designing a RF Birdcage Coil
In order to generate a homogeneous B1 field at the desiredfrequency;
use the correct capacitance valuecalculate an initial capacitance valuetuning and matching procedures
knowing resonant modes of the birdcage coiltuning and matching procedures can be done withoutinterfering with the other modesm=0 mode is used in open MRI systems
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Designing a RF Birdcage Coil
In order to generate a homogeneous B1 field at the desiredfrequency;
use the correct capacitance valuecalculate an initial capacitance valuetuning and matching procedures
knowing resonant modes of the birdcage coiltuning and matching procedures can be done withoutinterfering with the other modesm=0 mode is used in open MRI systems
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Designing a RF Birdcage Coil
In order to generate a homogeneous B1 field at the desiredfrequency;
use the correct capacitance valuecalculate an initial capacitance valuetuning and matching procedures
knowing resonant modes of the birdcage coiltuning and matching procedures can be done withoutinterfering with the other modesm=0 mode is used in open MRI systems
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Designing a RF Birdcage Coil
In order to generate a homogeneous B1 field at the desiredfrequency;
use the correct capacitance valuecalculate an initial capacitance valuetuning and matching procedures
knowing resonant modes of the birdcage coiltuning and matching procedures can be done withoutinterfering with the other modesm=0 mode is used in open MRI systems
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Simulating a RF Birdcage Coil
Solving for the electromagnetic fields of a birdcage coil at thespecified frequency.
B1 field distribution inside the coil
specific absorption rate (SAR) at any object
variation of any electromagnetic field variables with respectto frequency
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Simulating a RF Birdcage Coil
Solving for the electromagnetic fields of a birdcage coil at thespecified frequency.
B1 field distribution inside the coil
specific absorption rate (SAR) at any object
variation of any electromagnetic field variables with respectto frequency
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Simulating a RF Birdcage Coil
Solving for the electromagnetic fields of a birdcage coil at thespecified frequency.
B1 field distribution inside the coil
specific absorption rate (SAR) at any object
variation of any electromagnetic field variables with respectto frequency
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
Simulating a RF Birdcage Coil
Solving for the electromagnetic fields of a birdcage coil at thespecified frequency.
B1 field distribution inside the coil
specific absorption rate (SAR) at any object
variation of any electromagnetic field variables with respectto frequency
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Outline1 Introduction
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
2 MotivationReview of previous studiesProblem definitionOur work
3 MethodsFEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
4 Experimental Results5 Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Outline1 Introduction
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
2 MotivationReview of previous studiesProblem definitionOur work
3 MethodsFEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
4 Experimental Results5 Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Studies on Designing a Birdcage CoilTropp, 1989analyzing low-pass birdcage resonator - using lumped circuitelement model and perturbation theory
Jin, 1989resonant modes calculation - lumped circuit element model
Pascone et al., 1991analyzing both low-pass and high-pass birdcage coil - usingtransmission line theory
Leifer, 1997resonant modes calculation - using discrete Fourier transform
Chin et al., 2002capacitance calculation - lumped circuit element model
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Studies on Designing a Birdcage CoilTropp, 1989analyzing low-pass birdcage resonator - using lumped circuitelement model and perturbation theory
Jin, 1989resonant modes calculation - lumped circuit element model
Pascone et al., 1991analyzing both low-pass and high-pass birdcage coil - usingtransmission line theory
Leifer, 1997resonant modes calculation - using discrete Fourier transform
Chin et al., 2002capacitance calculation - lumped circuit element model
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Studies on Designing a Birdcage CoilTropp, 1989analyzing low-pass birdcage resonator - using lumped circuitelement model and perturbation theory
Jin, 1989 - MRIEM Software Toolresonant modes calculation - lumped circuit element model
Pascone et al., 1991analyzing both low-pass and high-pass birdcage coil - usingtransmission line theory
Leifer, 1997resonant modes calculation - using discrete Fourier transform
Chin et al., 2002capacitance calculation - lumped circuit element model
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Lumped Circuit Element Model
end rings and rungs are modeled as inductors
self and mutual inductances are calculated usinghandbook formulas
equivalent circuit model (LC network) is solved usingKirchoff’s voltage and current laws
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Lumped Circuit Element Model
end rings and rungs are modeled as inductors
self and mutual inductances are calculated usinghandbook formulas
equivalent circuit model (LC network) is solved usingKirchoff’s voltage and current laws
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Lumped Circuit Element Model
end rings and rungs are modeled as inductors
self and mutual inductances are calculated usinghandbook formulas
equivalent circuit model (LC network) is solved usingKirchoff’s voltage and current laws
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Lumped Circuit Element Model
end rings and rungs are modeled as inductors
self and mutual inductances are calculated usinghandbook formulas
equivalent circuit model (LC network) is solved usingKirchoff’s voltage and current laws
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Lumped Circuit Element Model
Figure: Equivalent lumped circuit element models for low-passand high-pass birdcage coils
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Outline1 Introduction
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
2 MotivationReview of previous studiesProblem definitionOur work
3 MethodsFEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
4 Experimental Results5 Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Limitation of Lumped Circuit Element Model
There are some limitations of using lumped circuit elementmodel
heavily depends on the inductance calculations
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Limitation of Lumped Circuit Element Model
There are some limitations of using lumped circuit elementmodel in the capacitance and resonant modes calculations:
heavily depends on the inductance calculations
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Limitation of Lumped Circuit Element Model
There are some limitations of using lumped circuit elementmodel in the capacitance and resonant modes calculations:
heavily depends on the inductance calculations
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Limitation of Lumped Circuit Element Model
There are some limitations of using lumped circuit elementmodel in the capacitance and resonant modes calculations:
heavily depends on the inductance calculations which aremade under the quasi-static assumption
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Limitation of Lumped Circuit Element Model
There are some limitations of using lumped circuit elementmodel in the capacitance and resonant modes calculations:
heavily depends on the inductance calculations which aremade under the quasi-static assumption
Example: L = 0.002l[
ln(
2lB
)
+ 0.5]
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Limitation of Lumped Circuit Element Model
There are some limitations of using lumped circuit elementmodel in the capacitance and resonant modes calculations:
heavily depends on the inductance calculations which aremade under the quasi-static assumption
Example: L = 0.002l[
ln(
2lB
)
+ 0.5]
frequency ↑
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Limitation of Lumped Circuit Element Model
There are some limitations of using lumped circuit elementmodel in the capacitance and resonant modes calculations:
heavily depends on the inductance calculations which aremade under the quasi-static assumption
Example: L = 0.002l[
ln(
2lB
)
+ 0.5]
frequency ↑ error ↑
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Modelling a Transmission Line as a Lumped CircuitElement
Deutsch et al., 1997There is an important criterion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Modelling a Transmission Line as a Lumped CircuitElement
Deutsch et al., 1997There is an important criterion - used for determining whether awire can be modeled as lumped circuit element or not -
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Modelling a Transmission Line as a Lumped CircuitElement
Deutsch et al., 1997There is an important criterion - used for determining whether awire can be modeled as lumped circuit element or not - which isgiven as
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Modelling a Transmission Line as a Lumped CircuitElement
Deutsch et al., 1997There is an important criterion - used for determining whether awire can be modeled as lumped circuit element or not - which isgiven as
length of wire ≤λ
20where λ is the wavelength.
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
Outline1 Introduction
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
2 MotivationReview of previous studiesProblem definitionOur work
3 MethodsFEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
4 Experimental Results5 Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
What Have We Done in this Study?
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
What Have We Done in this Study?
We have first developed FEM models of low-pass andhigh-pass birdcage coils in COMSOL Multiphysics.
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
What Have We Done in this Study?
We have first developed FEM models of low-pass andhigh-pass birdcage coils in COMSOL Multiphysics.
Using these models;
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
What Have We Done in this Study?
We have first developed FEM models of low-pass andhigh-pass birdcage coils in COMSOL Multiphysics.
Using these models;
Two FEM based simulation methods
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
What Have We Done in this Study?
We have first developed FEM models of low-pass andhigh-pass birdcage coils in COMSOL Multiphysics.
Using these models;
Two FEM based simulation methods
Frequency Domain Analysis
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
What Have We Done in this Study?
We have first developed FEM models of low-pass andhigh-pass birdcage coils in COMSOL Multiphysics.
Using these models;
Two FEM based simulation methods
Frequency Domain AnalysisEigenfrequency Analysis
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
What Have We Done in this Study?
We have first developed FEM models of low-pass andhigh-pass birdcage coils in COMSOL Multiphysics.
Using these models;
Two FEM based simulation methods
Frequency Domain AnalysisEigenfrequency Analysis
Software Tool
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
What Have We Done in this Study?
We have first developed FEM models of low-pass andhigh-pass birdcage coils in COMSOL Multiphysics.
Using these models;
Two FEM based simulation methods
Frequency Domain AnalysisEigenfrequency Analysis
Software Tool
FEM-FDA-EFAT
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Review of previous studiesProblem definitionOur work
What Have We Done in this Study?
We have first developed FEM models of low-pass andhigh-pass birdcage coils in COMSOL Multiphysics.
Using these models;
Two FEM based simulation methods
Frequency Domain AnalysisEigenfrequency Analysis
Software Tool
FEM-FDA-EFAT
A handmade low-pass birdcage coil is constructed.
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Outline1 Introduction
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
2 MotivationReview of previous studiesProblem definitionOur work
3 MethodsFEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
4 Experimental Results5 Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Outline1 Introduction
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
2 MotivationReview of previous studiesProblem definitionOur work
3 MethodsFEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
4 Experimental Results5 Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Geometry
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Geometry
low-pass and high-pass birdcage coils are geometricallymodeled in the simulation environment
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Geometry
low-pass and high-pass birdcage coils are geometricallymodeled in the simulation environment
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Adding Physics
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Adding Physics
Radio Frequency Branch → Electromagnetic WavesInterface
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Adding Physics
Radio Frequency Branch → Electromagnetic WavesInterface
solves the electromagnetic wave equation for the timeharmonic and eigenfrequency problem
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Adding Physics
Radio Frequency Branch → Electromagnetic WavesInterface
solves the electromagnetic wave equation for the timeharmonic and eigenfrequency problem
∇× µ−1r (∇× E)− k2
0
(
ǫr −jσωǫ0
)
E = 0
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Boundary Conditions
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Boundary Conditions
boundaries of rungs, end rings, capacitor plates and RFshield are assigned to Perfect Electric Conductor (PEC)
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Boundary Conditions
boundaries of rungs, end rings, capacitor plates and RFshield are assigned to Perfect Electric Conductor (PEC)
n × E = 0
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Boundary Conditions
boundaries of rungs, end rings, capacitor plates and RFshield are assigned to Perfect Electric Conductor (PEC)
n × E = 0
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Boundary Conditions
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Boundary Conditions
we need to prevent reflections from the outer boundary ofthe solution domain
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Boundary Conditions
we need to prevent reflections from the outer boundary ofthe solution domainscattering boundary condition → for boundaries
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Boundary Conditions
we need to prevent reflections from the outer boundary ofthe solution domainscattering boundary condition → for boundariesperfectly matched layer → for domain
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Boundary Conditions
we need to prevent reflections from the outer boundary ofthe solution domainscattering boundary condition → for boundariesperfectly matched layer → for domain
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Boundary Conditions
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Boundary Conditions
In frequency domain analysis, lumped port boundarycondition is used for voltage excitation (Zport =
VportIport
)
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Boundary Conditions
In frequency domain analysis, lumped port boundarycondition is used for voltage excitation (Zport =
VportIport
)
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Boundary Conditions
In frequency domain analysis, lumped port boundarycondition is used for voltage excitation (Zport =
VportIport
)
In eigenfrequency analysis, no source is appliedNecip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Mesh
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Mesh
(Element Size) <<λ5
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Mesh
(Element Size) <<λ5
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Outline1 Introduction
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
2 MotivationReview of previous studiesProblem definitionOur work
3 MethodsFEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
4 Experimental Results5 Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation of a Birdcage Coil
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation of a Birdcage Coil
solves for the electromagnetic fields in the solution domain
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation of a Birdcage Coil
solves for the electromagnetic fields in the solution domain
at the desired frequency (or frequencies)
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation of a Birdcage Coil
solves for the electromagnetic fields in the solution domain
at the desired frequency (or frequencies)
for the specified capacitance value
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation of a Birdcage Coil
solves for the electromagnetic fields in the solution domain
at the desired frequency (or frequencies)
for the specified capacitance value
In Frequency Domain Analysis;
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation of a Birdcage Coil
solves for the electromagnetic fields in the solution domain
at the desired frequency (or frequencies)
for the specified capacitance value
In Frequency Domain Analysis;
loaded (or unloaded) birdcage coils
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation of a Birdcage Coil
solves for the electromagnetic fields in the solution domain
at the desired frequency (or frequencies)
for the specified capacitance value
In Frequency Domain Analysis;
loaded (or unloaded) birdcage coils
shielded (or unshielded) birdcage coils
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation of a Birdcage Coil
solves for the electromagnetic fields in the solution domain
at the desired frequency (or frequencies)
for the specified capacitance value
In Frequency Domain Analysis;
loaded (or unloaded) birdcage coils
shielded (or unshielded) birdcage coils
linear or quadrature excitation
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results
three different scenarios;
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results
three different scenarios;
unloaded and unshielded 8-leg low-pass birdcage coil
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results
three different scenarios;
unloaded and unshielded 8-leg low-pass birdcage coil
unloaded and shielded 8-leg low-pass birdcage coil
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results
three different scenarios;
unloaded and unshielded 8-leg low-pass birdcage coil
unloaded and shielded 8-leg low-pass birdcage coil
loaded and shielded 16-leg high-pass birdcage coil
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results
three different scenarios;
unloaded and unshielded 8-leg low-pass birdcage coil
unloaded and shielded 8-leg low-pass birdcage coil
loaded and shielded 16-leg high-pass birdcage coil
electromagnetic field distributions
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results
three different scenarios;
unloaded and unshielded 8-leg low-pass birdcage coil
unloaded and shielded 8-leg low-pass birdcage coil
loaded and shielded 16-leg high-pass birdcage coil
electromagnetic field distributions
H+ and H−
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results
three different scenarios;
unloaded and unshielded 8-leg low-pass birdcage coil
unloaded and shielded 8-leg low-pass birdcage coil
loaded and shielded 16-leg high-pass birdcage coil
electromagnetic field distributions
H+ and H−
H+ =Hx + iHy
2H− =
(Hx − iHy )∗
2
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results
three different scenarios;
unloaded and unshielded 8-leg low-pass birdcage coil
unloaded and shielded 8-leg low-pass birdcage coil
loaded and shielded 16-leg high-pass birdcage coil
electromagnetic field distributions
H+ and H−
H+ =Hx + iHy
2H− =
(Hx − iHy )∗
2
E-field
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 1st ScenarioUnloaded and Unshielded 8-leg Low-pass BC
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 1st ScenarioUnloaded and Unshielded 8-leg Low-pass BC
H+ and H− → for linear excitation
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 1st ScenarioUnloaded and Unshielded 8-leg Low-pass BC
H+ and H− → for linear excitation
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 1st ScenarioUnloaded and Unshielded 8-leg Low-pass BC
H+ and H− → for quadrature excitation
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 1st ScenarioUnloaded and Unshielded 8-leg Low-pass BC
H+ and H− → for quadrature excitation
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 1st ScenarioUnloaded and Unshielded 8-leg Low-pass BC
Electric field → for linear and quadrature excitation
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 1st ScenarioUnloaded and Unshielded 8-leg Low-pass BC
Electric field → for linear and quadrature excitation
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 1st ScenarioUnloaded and Unshielded 8-leg Low-pass BC
H+ uniformity → for quadrature excitation
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 1st ScenarioUnloaded and Unshielded 8-leg Low-pass BC
H+ uniformity → for quadrature excitation
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 2nd ScenarioUnloaded and Shielded 8-leg Low-pass BC
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 2nd ScenarioUnloaded and Shielded 8-leg Low-pass BC
H+ uniformity → for quadrature excitation
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 2nd ScenarioUnloaded and Shielded 8-leg Low-pass BC
H+ uniformity → for quadrature excitation
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 3rd ScenarioLoaded and Shielded 16-leg High-pass BC
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 3rd ScenarioLoaded and Shielded 16-leg High-pass BC
Geometric model
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 3rd ScenarioLoaded and Shielded 16-leg High-pass BC
H+ → for unloaded and loaded case (quadrature excitation)
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 3rd ScenarioLoaded and Shielded 16-leg High-pass BC
H+ → for unloaded and loaded case (quadrature excitation)
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 3rd ScenarioLoaded and Shielded 16-leg High-pass BC
H− → for unloaded and loaded case (quadrature excitation)
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 3rd ScenarioLoaded and Shielded 16-leg High-pass BC
H− → for unloaded and loaded case (quadrature excitation)
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 3rd ScenarioLoaded and Shielded 16-leg High-pass BC
SAR distribution of an object
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 3rd ScenarioLoaded and Shielded 16-leg High-pass BC
SAR distribution of an object
SAR =σ|E|2
ρ
σ: conductivity, ρ: density
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 3rd ScenarioLoaded and Shielded 16-leg High-pass BC
SAR distribution of an object
SAR =σ|E|2
ρ
σ: conductivity, ρ: density
Normalized SAR distribution → for quadrature excitation
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 3rd ScenarioLoaded and Shielded 16-leg High-pass BC
Normalized SAR distribution → for quadrature excitation
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Outline1 Introduction
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
2 MotivationReview of previous studiesProblem definitionOur work
3 MethodsFEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
4 Experimental Results5 Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Resonant Mode Analysis of a Birdcage Coil
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Resonant Mode Analysis of a Birdcage Coil
calculates the resonant modes of the birdcage coil
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Resonant Mode Analysis of a Birdcage Coil
calculates the resonant modes of the birdcage coil and theelectromagnetic field distributions at these resonantmodes
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Resonant Mode Analysis of a Birdcage Coil
calculates the resonant modes of the birdcage coil and theelectromagnetic field distributions at these resonantmodes for the given capacitance value
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Eigenfrequency Analysis in COMSOL Multiphysics
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Eigenfrequency Analysis in COMSOL Multiphysics
use developed FEM models of birdcage coils
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Eigenfrequency Analysis in COMSOL Multiphysics
use developed FEM models of birdcage coils
add eigenfrequency study
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Eigenfrequency Analysis in COMSOL Multiphysics
use developed FEM models of birdcage coils
add eigenfrequency studyspecify number of eigenfrequencies
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Eigenfrequency Analysis in COMSOL Multiphysics
use developed FEM models of birdcage coils
add eigenfrequency studyspecify number of eigenfrequenciesspecify a frequency point
add eigenvalue solver
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Eigenfrequency Analysis in COMSOL Multiphysics
use developed FEM models of birdcage coils
add eigenfrequency studyspecify number of eigenfrequenciesspecify a frequency point
add eigenvalue solverchange the linearization point (if necessary)
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results
two different scenarios;
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results
two different scenarios;
unloaded and unshielded 8-leg low-pass birdcage coil
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results
two different scenarios;
unloaded and unshielded 8-leg low-pass birdcage coil
unloaded and shielded 16-leg high-pass birdcage coil
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results
two different scenarios;
unloaded and unshielded 8-leg low-pass birdcage coil
unloaded and shielded 16-leg high-pass birdcage coil
observed electromagnetic variables
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results
two different scenarios;
unloaded and unshielded 8-leg low-pass birdcage coil
unloaded and shielded 16-leg high-pass birdcage coil
observed electromagnetic variables
H+ at these resonant modes
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results
two different scenarios;
unloaded and unshielded 8-leg low-pass birdcage coil
unloaded and shielded 16-leg high-pass birdcage coil
observed electromagnetic variables
H+ at these resonant modes
surface current density
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 1st ScenarioUnloaded and Unshielded 8-leg Low-pass BC
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 1st ScenarioUnloaded and Unshielded 8-leg Low-pass BC
H+ → for all resonant modes
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 1st ScenarioUnloaded and Unshielded 8-leg Low-pass BC
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 2nd ScenarioUnloaded and shielded 16-leg High-pass BC
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 2nd ScenarioUnloaded and shielded 16-leg High-pass BC
H+ and surface current densities → for m=0 mode
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Simulation Results - 2nd ScenarioUnloaded and shielded 16-leg High-pass BC
H+ and surface current densities → for m=0 mode
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Outline1 Introduction
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
2 MotivationReview of previous studiesProblem definitionOur work
3 MethodsFEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
4 Experimental Results5 Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Software Tool for Designing and Simulating a BirdcageCoil
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Software Tool for Designing and Simulating a BirdcageCoil
PURPOSE:
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Software Tool for Designing and Simulating a BirdcageCoil
PURPOSE:
To provide convenience for the coil designers and theresearchers in the field of MRI
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Software Tool for Designing and Simulating a BirdcageCoil
PURPOSE:
To provide convenience for the coil designers and theresearchers in the field of MRI to use the proposedsimulation methods easily and according to the parametersthey specify
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Software Tool for Designing and Simulating a BirdcageCoil
PURPOSE:
To provide convenience for the coil designers and theresearchers in the field of MRI to use the proposedsimulation methods easily and according to the parametersthey specify
developed software tool
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Software Tool for Designing and Simulating a BirdcageCoil
PURPOSE:
To provide convenience for the coil designers and theresearchers in the field of MRI to use the proposedsimulation methods easily and according to the parametersthey specify
developed software tool
FEM based Frequency Domain and EigenfrequencyAnalysis Tool (FEM-FDA-EFAT)
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Properties of the sofware tool
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Properties of the sofware tool
developed in MATLAB
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Properties of the sofware tool
developed in MATLAB
has graphical-user-interface (GUI)
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Properties of the sofware tool
developed in MATLAB
has graphical-user-interface (GUI)makes all design and simulation steps according to theuser-specified parameters by connecting to the COMSOLMultiphysics server
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Properties of the sofware tool
developed in MATLAB
has graphical-user-interface (GUI)makes all design and simulation steps according to theuser-specified parameters by connecting to the COMSOLMultiphysics server
modeling the coil geometry
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Properties of the sofware tool
developed in MATLAB
has graphical-user-interface (GUI)makes all design and simulation steps according to theuser-specified parameters by connecting to the COMSOLMultiphysics server
modeling the coil geometryadding physics and boundary condition
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Properties of the sofware tool
developed in MATLAB
has graphical-user-interface (GUI)makes all design and simulation steps according to theuser-specified parameters by connecting to the COMSOLMultiphysics server
modeling the coil geometryadding physics and boundary conditiongenerating mesh for the model
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Properties of the sofware tool
developed in MATLAB
has graphical-user-interface (GUI)makes all design and simulation steps according to theuser-specified parameters by connecting to the COMSOLMultiphysics server
modeling the coil geometryadding physics and boundary conditiongenerating mesh for the modeladding study and solver sequence
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Properties of the sofware tool
developed in MATLAB
has graphical-user-interface (GUI)makes all design and simulation steps according to theuser-specified parameters by connecting to the COMSOLMultiphysics server
modeling the coil geometryadding physics and boundary conditiongenerating mesh for the modeladding study and solver sequencecomputing the solutions
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
Properties of the sofware tool
developed in MATLAB
has graphical-user-interface (GUI)makes all design and simulation steps according to theuser-specified parameters by connecting to the COMSOLMultiphysics server
modeling the coil geometryadding physics and boundary conditiongenerating mesh for the modeladding study and solver sequencecomputing the solutions
when the computation is finished, results can be observedin COMSOL Multiphysics
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
FEM-FDA-EFAT
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
FEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
FEM-FDA-EFAT
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Outline1 Introduction
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
2 MotivationReview of previous studiesProblem definitionOur work
3 MethodsFEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
4 Experimental Results5 Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Handmade Low-pass Birdcage Coil
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Handmade Low-pass Birdcage Coil
8-leg low-pass birdcage coil is constructed on plexiglasstube
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Handmade Low-pass Birdcage Coil
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Experimental Results and Comparison with NumericalAnalyses
for the resonant modes
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Experimental Results and Comparison with NumericalAnalyses
for the resonant modes
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Experimental Results and Comparison with NumericalAnalyses
for the resonant modes
S11 of the coil for five different capacitance values
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Experimental Results and Comparison with NumericalAnalyses
for the resonant modes
S11 of the coil for five different capacitance valuescompare the measured resonant modes
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Experimental Results and Comparison with NumericalAnalyses
for the resonant modes
S11 of the coil for five different capacitance valuescompare the measured resonant modes
Jin’s software tool, MRIEM
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Experimental Results and Comparison with NumericalAnalyses
for the resonant modes
S11 of the coil for five different capacitance valuescompare the measured resonant modes
Jin’s software tool, MRIEMOur software tool, FEM-EFAT
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Experimental Results and Comparison with NumericalAnalyses
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Experimental Results and Comparison with NumericalAnalyses
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Measured and Calculated Resonant ModesResults for Low-pass Birdcage Coil
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Measured and Calculated Resonant ModesResults for Low-pass Birdcage Coil
used capacitance values
47 pF, 10 pF, 3.3 pF, 1.8 pF, 1 pF
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Measured and Calculated Resonant ModesResults for Low-pass Birdcage Coil
Results for 47pF
Modes Measured (MHz) MRIEM (MHz) FEM-EFAT (MHz)m=1 60.75 67.46 59.1m=2 85.88 90.64 87.22m=3 93.38 102.2 101.1m=4 102.8 - 105.4
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Measured and Calculated Resonant ModesResults for Low-pass Birdcage Coil
Results for 10pF
Modes Measured (MHz) MRIEM (MHz) FEM-EFAT (MHz)m=1 122.11 146.25 124.76m=2 196.48 196.51 184.80m=3 208.54 221.57 214.41m=4 214.97 - 223.54
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Measured and Calculated Resonant ModesResults for Low-pass Birdcage Coil
Results for 3.3pF
Modes Measured (MHz) MRIEM (MHz) FEM-EFAT (MHz)m=1 211.3 254.59 205.37m=2 306.3 342.08 306.62m=3 330.0 385.71 356.47m=4 345.0 - 371.75
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Measured and Calculated Resonant ModesResults for Low-pass Birdcage Coil
Results for 1.8pF
Modes Measured (MHz) MRIEM (MHz) FEM-EFAT (MHz)m=1 255.2 344.71 260.62m=2 382.0 463.19 392.18m=3 417.0 522.26 456.8m=4 441.5 - 476.5
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Measured and Calculated Resonant ModesResults for Low-pass Birdcage Coil
Results for 1pF
Modes Measured (MHz) MRIEM (MHz) FEM-EFAT (MHz)m=1 335.7 462.48 316.85m=2 473.1 621.42 481.6m=3 512.3 700.68 562.24m=4 525.9 - 586.63
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Measured and Calculated Resonant ModesResults for Low-pass Birdcage Coil
Percentage error
Error rate (%) = 100 ×
∣
∣
∣
∣
fmeas − fcalc
fmeas
∣
∣
∣
∣
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Measured and Calculated Resonant ModesResults for Low-pass Birdcage Coil
Percentage error rate for FEM-EFAT and MRIEM
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Outline1 Introduction
RF coils in MRIRF birdcage coilsDesign and simulation of RF birdcage coils
2 MotivationReview of previous studiesProblem definitionOur work
3 MethodsFEM Models of Birdcage CoilsFrequency Domain AnalysisEigenfrequency AnalysisSoftware Tool
4 Experimental Results5 Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Conclusion
We have proposed two FEM based simulation methods usingdeveloped FEM models of low-pass and high-passbirdcage coils in COMSOL Multiphysics:
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Conclusion
We have proposed two FEM based simulation methods usingdeveloped FEM models of low-pass and high-passbirdcage coils in COMSOL Multiphysics:
Frequency Domain Analysis
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Conclusion
We have proposed two FEM based simulation methods usingdeveloped FEM models of low-pass and high-passbirdcage coils in COMSOL Multiphysics:
Frequency Domain Analysiselectromagnetic fields solutions of a birdcage coil for anyscenario
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Conclusion
We have proposed two FEM based simulation methods usingdeveloped FEM models of low-pass and high-passbirdcage coils in COMSOL Multiphysics:
Frequency Domain Analysiselectromagnetic fields solutions of a birdcage coil for anyscenario
Eigenfrequency Analysis
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Conclusion
We have proposed two FEM based simulation methods usingdeveloped FEM models of low-pass and high-passbirdcage coils in COMSOL Multiphysics:
Frequency Domain Analysiselectromagnetic fields solutions of a birdcage coil for anyscenario
Eigenfrequency Analysisresonant modes of a birdcage coil and electromagnetic fieldsolutions at these resonant modes
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Conclusion
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Conclusion
A software tool is developed to make these two simulationmethods easily and according to the user-specifiedparameters
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Conclusion
A software tool is developed to make these two simulationmethods easily and according to the user-specifiedparameters
Experimental results show that results of the proposedsoftware tool is more accurate than the results of softwaretool which uses lumped circuit element model
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
Conclusion
A software tool is developed to make these two simulationmethods easily and according to the user-specifiedparameters
Experimental results show that results of the proposedsoftware tool is more accurate than the results of softwaretool which uses lumped circuit element model
These methods can be adapted to design and simulateother MRI RF coils
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
One more thing...
Necip Gurler COMSOL CONFERENCE EUROPE 2012
IntroductionMotivation
MethodsExperimental Results
Conclusion
One more thing...
Necip Gurler COMSOL CONFERENCE EUROPE 2012
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