MRI parameters
Increasing the TR will: a- Improve SNR b- Increase Scan Time c- Reduce T1 weighting d- Increase the available # of slices
All of the above
Gradient echo pulse sequence summery
variable RF followed by gradient to produce echo
In a Spin echo pulse sequence the location halfway between the 90 degree pulse and the 180 degree pulse is known as?
1/2 TE (Tau)
Inversion recovery pulse sequence summery
180, followed by 90
Spin echo pulse sequence summery
90,180
Fast spin echo pulse sequence summery
90,180,180,180
Decreasing the TR will: a- Lower the SNR b- Reduce scan time c-Increase T1 weighting d- Reduce the available # of slices
All of the above
T2* gradient echo pulse sequences require a high amount of ____?
Fluid
What gradient is turned on during the production of the echo is _________?
Frequency or Readout gradient
the timing of RF pulses in an MRI pulse sequence controls ?
Image Contrast
What is the controlling factor of T2 weighting contrast of an image?
Echo Time (TE)
What is the fastest pulse sequence commonly available?
Echo planar Imaging (EPI)
True or false, Gradient echo pulse sequences utilize a 180 degree pulse in the beginning of the sequence?
False
If TR is increased the number of slices allowed is?
Increased
What happens to the SNR if the NEX is increased?
It will increase by the square root of the % of the increase.
Water has a ______ T1 relaxation time and a ______ T2 relation time.
Long T1, Long T2
What weighted image are created with the following parameters? TR-1500-3000ms TE-10-30ms
Proton Density
What is the controlling factor of T1 weighting contrast of an image?
Repetition Time (TR)
What happens to Scan Time if the TR is doubled?
Scan Time will double (TR X Phase Matrix X NEX)
Fat has a _______ T1 relaxation time and a ________ T2 relaxation time.
Short T1, Short T2
Incoherent or Spoiled gradient echo pulse sequences produce what image weighting contrast?
T1
What weighted image are created with the following parameters? TR-350-700ms TE-10-30ms
T1 Weighted
Gradient echo pulse sequences produce what image weighting?
T1 and T2*
What weighted image are created with the following parameters? TR-2000-6000ms TE-70-120ms
T2 weighted image
Scan time is calculated by this formula
TR X Phase Matrix X NEX = scan in milliseconds divided by 1000
If the TE is increased, the amount of slices allowed is ?
decreased
Increasing the TR does what to the T1 image contrast
decreases