Data Acqusition and processing Flashcards
When applying a conventional spin echo pulse sequence, how many lines of k-space are filled per TR period?
1
During conventional spin echo imaging, only one line of k-space gets filled ruing each :
TR
Due to their relatively slow k-space filling, conventional spin echo pulse sequences are usually only used when acquiring
T1 weighted imaging
When applying a fast spine echo pules sequence, the number of lines in k-space that are filled per TR period are dependent on the
ETL Selected
During FSE sequence with ETL of 8, 8 lines of k-space are filled per acquisition.
Increasing the ETL during FSE sequences causes acqusition time to go up or down?
It goes down
What FSE pulse sequence uses a partial fourier technique to fill all lines of k-space during a single TR period
Single shot fast spin echo (SS-FSE)
The use of Single shot fast spin echo instead of FSE or CSE pulse sequence causes :
Increased tissue heating
The abbreviation “DRIVE” stands for
Driven equilibrium fourier transform
What FSE pulse sequence uses a reverse flip angle excitation pulse after the applied echo train in order to push the transverse magnetization into the longitudinal plane so that T1 relaxation can occur at a quicker rate?
Driven Equilibrium fourier transform
What pulse sequence represents a DRIVE sequence
90-180-180-90
DRIVE sequences yield _______ fluid signal compared to standard FSE pulse sequences
Hyperintense
At 1.5T which inversion time (TI) would produce the best STIR image?
150ms
Ranges of 100-175
At 1.5T which inversion time (TI) would produce the best FLAIR image?
2000ms
Ranges of 1700-2200ms
Gradient echo pulse sequences use what gradient to rephase the FID?
The frequency encoding gradient
What type of pulse sequence would best demonstrate subtle hemorrhage in the brain
Gradient echo pulse sequences
T1 weighted conventional gradient echo pulse sequence generally require the use of a _________ flip angle
Large
T2 weighted conventional gradient echo pulse sequence generally require the use of a _________ flip angle
Small
PD weighted conventional gradient echo pulse sequence generally require the use of a _________ flip angle
Small
What sub group of GE pulse sequences uses two excitation pulses in order to create a stimulated echo?
Steady state pulse sequences
What type of pulse sequence maintains partial longitudinal and transverse magnetization at all times?
Steady state pulse sequences
During steady state pulse sequnces the NMV is never allowed to return to the _______ axis
Longitudinal
What term is used to describe the partial longitudinal and transverse magnetization that is maintained during steady state pulse sequences?
Residual transverse magnetization
During a steady state pulse sequence, if two excitation pulses with variable degree flip angle are applied, a ___________ echo is created
Stimulated
If a steady state pulse sequence uses two 90 degree excitation pulses, the echo that is created is called a
Hann Echo
Steady state pulse sequences typically used flip angles within the range of
30-45 degrees
What type of steady state pulse sequence only samples the gradient echo? (FID)
Incoherent gradient echo
The flip angles applied during incoherent gradient echo pulse sequences fall within a range of
30-45 degrees
Coherent GE pulse sequences apply what type of gradients in order to allow both the gradient echo (FID) and stimulated echo to contribute to image contrast
Rewinder gradients
Coherent gradient echo sequences are typically used to obtain what weighted images?
T2*
The flip angles applied during coherent gradient echo pulse sequences fall within a range of
30-45 degrees
What type of steady state pulse sequence only samples the stimulated echo?
Steady state free precession (SSFP)
Steady state free precession pulse sequences apply what type of gradients in order to rephase the stimulated echo so that it may contribute to image contrast
Rewinder gradients
The flip angles applied during steady state free precession pulse sequences fall within a range of
30-45 degrees
During echo planar sequences, k space is filled
Line by line in a stair-stepped fashion
The fastest form of data acquisition is achieved by which pulse sequence?
Echo planar pulse sequences
