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T1 Conventional MRI scan (SE)
- term
- TR-TE
- what primarily controls the contrast?
- NMV in what direction
- ?-? relaxsation
- energy given to...
- ... time contrast
- shows...
- what is bright
- relation to field strength
↧
- - time to get to a point where longitudinal magnetization has returned to 63% of its final value
- - TR↧ - TE↧
- - TR primarily controls the contrast
- - NMV in longitudinal (Z) direction
- - spin-lattice relaxation
- - energy given to surrounding tissue (other lattice)
- - tissue-specific time constant
- - shows anatomy (bone)
- - fat is bright
- - T1 longer at higher field strengths

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Time to get to a point where longitudinal magnetization has returned to 63% of its final value
T1
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In what MRI scan TR↧ - TE↧?
T1
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In T1 Conventional MRI scan what controls contrast?
TR primarily controls the contrast
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T1 Conventional MRI scan NMV in what direction?
NMV in longitudinal (Z) direction
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In T1 Conventional MRI scan energy given to...
?-? relaxation
- - energy given to surrounding tissue (other lattice)
- - spin-lattice relaxation
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T1 Conventional MRI scan shows...
- shows anatomy (bone)
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In T1 Conventional MRI scan what is bright?
- fat is bright
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How T1 Conventional MRI scan related to field strength?
- T1 longer at higher field strengths
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Time to get to a point where transverse magnetization decay to 37% of its original value
T2
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In what MRI scan TR↥ - TE↥?
T2
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In T2 Conventional MRI scan what controls contrast?
TE primarily controls the contrast
-
In T2 Conventional MRI scan NMV in what direction?
NMV in transverse (X-Z) plane
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In T2 Conventional MRI scan energy given to...
?-? relaxation
- - energy is exchanged to other spin of the same lattice
- - spin-spin interaction
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T2 Conventional MRI scan shows...
- shows pathology (fluid)
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In T2 Conventional MRI scan what is bright?
- fluid is bright
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How T2 Conventional MRI scan related to field strength?
- T2 unrelated to field strength
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spin-spin interaction?
T2
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spin-lattice relaxation?
T1
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-
-
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longer at higher field strengths
T1
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unrelated to field strength
T2
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FID
- - Free Induction Decay
- - Eddy Current
- - occur before T1 and T2 (leakage current)
- - caused by MF inhomogeneous
- - decays along transverse plan
- - when reach X-Y plan, becomes - T2*
- - best for nerve roots
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T2*
- product of FID
- when FID reach X-Y plan, becomes - T2*
- FID - Free Induction Decay
- Eddy Current
- occur before T1 and T2 (leakage current)
- caused by MF inhomogeneous
- dephasing the P spin
- best for nerve roots
- decays along transverse plan X-
 
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Spin Echo PS
- SE Pulse Sequence:
- - has 2 RF - starts w 90, ends w 180
- - FID - Free Induction Decay
- - TR - Time to repeat
- - TE - Time to echo
- - T1, T2, PD - SE

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PD Conventional MRI scan
- PD - Proton Density
- Brightest signal in MRI
- Intermediate Pulse Sequence
- TR↥ - TE↧
- grayer in appearance
- b/c 15% tissue differentiation
- Pathology and anatomy

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TR primarily controls the contrast in...
T1 (TR↧ - TE↧)
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TE primarily controls the contrast in...
T2 (TR↥ - TE↥)
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Brightest signal in MRI
PD - Proton Density
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Intermediate Pulse Sequence
PD - Proton Density
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TR↥ - TE↧
PD - Proton Density
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What Pulse Sequence is grayer in appearance
PD - Proton Density
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What Pulse Sequence is good for pathology and anatomy
PD - Proton Density
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FSE Sequence
- Fast Spin Echo
- start w 90 followed by a train of 180
- quicker scanning times
- causes blurring as MRI is a trade-off b/w parameteres
- blurriness is solved by keeping ETL as low as possible
- ETL - Echo Train Length - # of 180 pulses after the 90 pulse

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ETL
- - Echo Train Length in Fast Spin Echo
- - # of 180 pulses after the 90 pulse

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IR Sequence
- Inversion Recovery
- start w 180 followed by 90
- 180° RF inversion wave
- 90° RF excitation wave
- TI - Time to invert (delay between 180° and 90°)
- TI controls contrast
- Bone black - if white - pathology

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STIR sequences
- Short TAU Inversion Recovery
- TAU - The interpulse times
- - time between the 90° and 180° pulse, and between the 180° pulse and the echo
- Good for:
- - osteomyelitis
- - all bone work

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FLAIR sequences
- Fluid Attenuated Inversion Recovery
- Good for:
- - multiple sclerosis
- - whenever CSF flow

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Gradient GRE echo
- Grade and Echo
- the flip angle usually below 90°
- the absence of a 180° RF rephasing pulse (GRE instead)

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T1 GRE
- T1 Grade and Echo
- TR↧ - TE↧
- Flip Ang ↥ <90
- the absence of a 180° RF rephasing pulse (GRE instead)
- MRA - Angiography
- Blood is bright

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T2 GRE
- T2 Grade and Echo
- TR↥ - TE↥
- Flip Ang ↧ <90
- the absence of a 180° RF rephasing pulse (GRE instead)
- Blood imaging

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Spin start w 90 followed by a train of 180
Fast Spin Echo
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Spin with quicker scanning times
Fast Spin Echo
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Why Fast Spin causes blurring?
causes blurring as MRI is a trade-off b/w parameters
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How to solve blurriness in Fast Spin Echo?
- - by keeping ETL as low as possible
- - ETL - Echo Train Length - # of 180 pulses after the 90 pulse
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Spin start w 180 followed by 90
Inversion Recovery
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What kind of wave are 180 and 90 in Inversion Recovery?
- - 180° RF inversion wave
- - 90° RF excitation wave
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In what sequence TI controls contrast?
Inversion Recovery
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What is TI?
- - Time to Invert
- - delay between 180° and 90° in Inversion Recovery

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In what spin if bone black - pathology?
- Inversion Recovery
- Bone black - if white - pathology
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In what spin the flip angle usually below 90° with the absence of a 180° RF rephasing pulse (GRE instead)
Gradient GRE echo
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What is ETL?
- - Echo Train Length in Fast Spin Echo
- - # of 180 pulses after the 90 pulse
-
Good for all bone work
STIR sequences
-
Good for osteomyelitis
STIR sequences
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Good for CSF flow
FLAIR sequences
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Good for multiple sclerosis
FLAIR sequences
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What Grade and Echo
TR↧ - TE↧
T1 GRE
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What Grade and Echo
Flip Ang ↥ <90
T1 GRE
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What Grade and Echo
TR↥ - TE↥
T2 GRE
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What Grade and Echo
Flip Ang ↧ <90
T2 GRE
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