-
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
-
-
Time to get to a point where longitudinal magnetization has returned to 63% of its final value
T1
-
In what MRI scan TR↧ - TE↧?
T1
-
In T1 Conventional MRI scan what controls contrast?
TR primarily controls the contrast
-
T1 Conventional MRI scan NMV in what direction?
NMV in longitudinal (Z) direction
-
In T1 Conventional MRI scan energy given to...
?-? relaxation
- - energy given to surrounding tissue (other lattice)
- - spin-lattice relaxation
-
T1 Conventional MRI scan shows...
- shows anatomy (bone)
-
In T1 Conventional MRI scan what is bright?
- fat is bright
-
How T1 Conventional MRI scan related to field strength?
- T1 longer at higher field strengths
-
Time to get to a point where transverse magnetization decay to 37% of its original value
T2
-
In what MRI scan TR↥ - TE↥?
T2
-
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
-
In T2 Conventional MRI scan energy given to...
?-? relaxation
- - energy is exchanged to other spin of the same lattice
- - spin-spin interaction
-
T2 Conventional MRI scan shows...
- shows pathology (fluid)
-
In T2 Conventional MRI scan what is bright?
- fluid is bright
-
How T2 Conventional MRI scan related to field strength?
- T2 unrelated to field strength
-
spin-spin interaction?
T2
-
spin-lattice relaxation?
T1
-
-
-
-
-
longer at higher field strengths
T1
-
unrelated to field strength
T2
-
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
 
-
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-
-
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
-
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
-
TR primarily controls the contrast in...
T1 (TR↧ - TE↧)
-
TE primarily controls the contrast in...
T2 (TR↥ - TE↥)
-
Brightest signal in MRI
PD - Proton Density
-
Intermediate Pulse Sequence
PD - Proton Density
-
-
-
TR↥ - TE↧
PD - Proton Density
-
What Pulse Sequence is grayer in appearance
PD - Proton Density
-
What Pulse Sequence is good for pathology and anatomy
PD - Proton Density
-
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
-
ETL
- - Echo Train Length in Fast Spin Echo
- - # of 180 pulses after the 90 pulse
-
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
-
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
-
-
FLAIR sequences
- Fluid Attenuated Inversion Recovery
- Good for:
- - multiple sclerosis
- - whenever CSF flow
-
Gradient GRE echo
- Grade and Echo
- the flip angle usually below 90°
- the absence of a 180° RF rephasing pulse (GRE instead)
-
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
-
T2 GRE
- T2 Grade and Echo
- TR↥ - TE↥
- Flip Ang ↧ <90
- the absence of a 180° RF rephasing pulse (GRE instead)
- Blood imaging
-
Spin start w 90 followed by a train of 180
Fast Spin Echo
-
Spin with quicker scanning times
Fast Spin Echo
-
Why Fast Spin causes blurring?
causes blurring as MRI is a trade-off b/w parameters
-
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
-
Spin start w 180 followed by 90
Inversion Recovery
-
What kind of wave are 180 and 90 in Inversion Recovery?
- - 180° RF inversion wave
- - 90° RF excitation wave
-
In what sequence TI controls contrast?
Inversion Recovery
-
What is TI?
- - Time to Invert
- - delay between 180° and 90° in Inversion Recovery
-
In what spin if bone black - pathology?
- Inversion Recovery
- Bone black - if white - pathology
-
In what spin the flip angle usually below 90° with the absence of a 180° RF rephasing pulse (GRE instead)
Gradient GRE echo
-
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
-
Good for CSF flow
FLAIR sequences
-
Good for multiple sclerosis
FLAIR sequences
-
What Grade and Echo
TR↧ - TE↧
T1 GRE
-
What Grade and Echo
Flip Ang ↥ <90
T1 GRE
-
What Grade and Echo
TR↥ - TE↥
T2 GRE
-
What Grade and Echo
Flip Ang ↧ <90
T2 GRE
|
|
