Post Test Questions 6 & 7 & 8

Front 1

transverse images of knee are being acquired with a pulse sequence which allows for flow comp. which direction is flow comp. best applied to reduce motion artifact from popliteal artery?

Back 1

Slice direction

Front 2

Spectral fat sat. increases SAR..T or F

Back 2

True

Front 3

Motion artifact techniques are not generally used in MRA.. T or F?

Back 3

False

Front 4

If gradient moment nulling is applied only along the slice direction of a transverse set of brain images, which physical gradient must use extra pulses..?

Back 4

Z-gradient

Front 5

When gradient moment nulling is added to a pulse sequence and all other parameters are unchanged the..?

-Min. echo time may be increased

-Scan time may be increased

-Size of anatomy may be decreased

-SAR of sequence may be increased

Back 5

Min. echo time may be increased

Front 6

In which direction must the artifact from motion appear in the image..?

Back 6

Phase direction

Front 7

Which statement is false regarding gradient moment nulling..?

-uses extra gradient pulses to rephase the signal from moving protons

-tends to be effective reducing CSF pulsation artifacts

-only rephases moving protons not stationary protons.

-vessels generally appear bright.

Back 7

Only rephases moving protons

Front 8

Which of the following has no effect upon scan time.

-respiratory triggering

-respiratory gating

-respiratory compensation

Back 8

Respiratory comp.

Front 9

Respiratory compensation does what..?

Back 9

Reorders the filling of the rawdata

Front 10

Spoiler after a 90 sat pulse.. dephases the

__ mag.

Back 10

Transverse

Front 11

Which of the gradients is not balanced for phase prior to collecting echo..?

Back 11

phase

Front 12

If the thickness of a single sat region is doubled, the SAR will..?

Back 12

Be unaffected

Front 13

which of the following techniques may shorten the scan time..?

-pulse gating

-respiratory gating

-spectral fat supp.

-ECG triggering

Back 13

ECG triggering

Front 14

what are some of the reasons gradient moment nulling is not typically used on T1- weighted images..?

Back 14

-most moving fluids have low intensity

-important to maintain short echo times

-multiple signal averages are used

Front 15

PT 7

Front 16

gradient echo sequences are rarely used for delineating tumors because..?

Back 16

they do not show true T2 contrast

Front 17

Volume- which gradients are responsible for phase encoding operation of dividing the volume into sagittal slices..?

Back 17

X and Y gradients

Front 18

PT8

Front 19

An acute artifact appears __ on the DW image and __ on the ADC image.

Back 19

Bright, Dark

Front 20

Which technique provides the best stationary tissue suppression?

Back 20

PCA

Front 21

the __ of the blood is responsible for the bright signal in TOF.

Back 21

flow

Front 22

which of the following results from reducing the volume of vessels to which MIP is applied..?

-reduces vessel overlap

-increases vessel contrast

-reduces processing time

Back 22

all

Front 23

When RF is repeatedly transmitted into the same tissues what happens to the nmv amplitude..?

increase or decrease..

Back 23

Decreases

Front 24

Relevant B0 values are in the range of..?

Back 24

500 to 1200 s/mm

Front 25

An ADC image:

Back 25

Will show an acute infarct as hypo intense to healthy surrounding tissue.

Front 26

What would happen to the background tissue in a 3D TOF if TR is shortened..?

RF pulse being repeated more rapidly)

Back 26

Stationary tissue would appear darker

Front 27

in perfusion imaging what happens to signal intensity as contrast passes..?

Back 27

Gets darker on the T2 image

pg.37 great discription

Front 28

The degree of stenosis may be overestimated with TOF because dephase due to __ flow __ to the stenosis causing reduction in signal.

Back 28

Turbulent, distal

Front 29

In spectroscopy __ is not required.

-shimming

-MIPing

-water suppression

Back 29

MIPing