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