대대대대대대대대대 대대대대대 대 대 대 대 대 대 M R Basic Physics Basic Physics
대구가톨릭대학병원 영상의학과이 영 환이 영 환
MMRRBasic PhysicsBasic Physics
MR SignalMR Signal
T1-, T2-weightedT1-, T2-weighted
TR, TETR, TE
MR SignalMR Signal
T1-, T2-weightedT1-, T2-weighted
TR, TETR, TE
Radiography, CTRadiography, CT
X-ray
Penetration
UltrasonographyUltrasonography
Ultrasound
Reflection
MRIMRI?RF Pulse
H1
1
RF Pulse
Resonance
Surface Coil
N
S
++
H1
1
Magnetic DipoleMagnetic Dipole
N
S
MagnetizationMagnetization
Magnetic Strength
GaussTesla1 Tesla = 10,000 Gauss
N
S
PrecessionPrecession
PrecessionPrecessionN
S
Resonance
Precession frequencyLarmor frequency
BB00 BB00
Frequency(MHz)
10-4
102
108
1014
1020
RadioVisible
light
X-raysGamma rays
Cosmic rays
MRMR
Electromagnetic WaveElectromagnetic Wave
Microwave
Surface Coil
N
S
N
S
Z
Y
X
N
S
N
S
Z
Y
X
N
S
N
S
Z
Y
X
N
S
Y
X
Z
N
S
LongitudinalMagnetization
TransverseMagnetization
Z
Y
X
N
S
Y
X
Z
N
S
LongitudinalMagnetization
TransverseMagnetization
Effect of RF Pulse
Loss of longitudinal M.Creation of transverse M.
– In Phase
Z
Y
X
Y
X
Z
MR SignalMR Signal
MR SignalMR Signal
T1-, T2-weightedT1-, T2-weighted
TR, TETR, TE
MR SignalMR Signal
T1-, T2-weightedT1-, T2-weighted
TR, TETR, TE
Resonance
E2
E1
; Induction of transition between two energy states
N
S
N
S
N
S
N
S
RelaxationRelaxation
Y
X
Z
Y
X
Z
RelaxationRelaxation
Relaxation
T1 Relaxation T2 Relaxation
; Process determining return to equilibrium of both longitudinal & transverse magnetization
T1 RelaxationT1 Relaxation
N
S
N
S
N
S
N
S
Z
Y
X
T1 RelaxationT1 Relaxation
T1 RelaxationT1 RelaxationLongitudinal
Magnetization
Time
N
S
T2 RelaxationT2 RelaxationN
S
BB00
Transversemagnetization
T2 RelaxationT2 Relaxation
Time
N
S
N
S
RelaxationRelaxation
Y
X
Z
Y
X
Z
RelaxationRelaxation
Transversemagnetization
T2 RelaxationT2 Relaxation
Time
Transversemagnetization
T2 RelaxationT2 Relaxation
Time
TE
T2 ContrastT2 Contrast
Time
Short T2 TissueLong T2 Tissue
T2-weightedT2-weighted
Time
Short T2 TissueLong T2 Tissue
Long TE
TE ; 28 msec TE ; 90 msec TE ; 230 msec
TR ; 3000 msec
Spatial LocalizationSpatial Localization
TE
TR
T1 RelaxationT1 RelaxationLongitudinal
Magnetization
Time
T1 ContrastT1 Contrast
Time
Short T1 Tissue
Long T1 Tissue
T1-weightedT1-weighted
Time
Short T1 Tissue
Long T1 Tissue
Short TR
TR ; 150 msec TR ; 500 msec TR ; 1500 msec
120 - 60
40 - 10
300 - 800 1500 - 4000TR (msec)
TE (msec)
Spin EchoSpin Echo
Poor contrastPoor S/N
Poor contrastPoor S/N T2
?T1
TR 3000 msec, TR 28 msec
120 - 60
40 - 10
300 - 800 1500 - 4000TR (msec)
TE (msec)
Spin EchoSpin Echo
Poor contrastPoor S/N
Poor contrastPoor S/N T2
ProtonT1 ?
Normal Tissue
Proton DensityT1T2
Lesion
Proton DensityT1T2
Normal Tissue
LesionLesion
IntrinsicIntrinsicTissueTissue
ContrastContrast
TRTRTETE
NEXNEXMatrixMatrixFOVFOV
Slice ThicknessSlice ThicknessMagnetic StrengthMagnetic Strength
Pulse SequencePulse Sequence........
TRTRTETE
NEXNEXMatrixMatrixFOVFOV
Slice ThicknessSlice ThicknessMagnetic StrengthMagnetic Strength
Pulse SequencePulse Sequence........
ExtrinsicExtrinsicImagingImaging
ParametersParametersImageImage
ContrastContrast
MR SignalMR Signal
T1-, T2-weightedT1-, T2-weighted
TR, TETR, TE
BB00
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