MRI Parameters Flashcards
If we increase the TR, what will this do to the scan time?
Increase
increased tr increased scan time
If we increase the TR, what will this do to the signal to noise ratio?
increase
increase TR increase SNR
What affect does increasing or decreasing the TR do to the effect on detail?
UNCHANGED
If we increase the TR, what will this do to the SAR?
Decreases
increase TR decreases SAR
inversely related
When you increase the TR, does this increase or decrease the T1 weighting?
increasing TR decreases the T1 Weighting.
If we increase the TE, what will this do to the SNR?
Decrease SNR
Increasing your TE will DECREASE the SNR
inversily related
If we decrease the TR, what will this do to the scan time?
decrease
decrease TR decrease scan time
If we decrease the TR, what will this do to the signal to noise ratio?
Decrease the SNR
If we decrease the TR, what will this do to the SAR?
increases the SAR
If we increase the TE, what will this do to the scan time?
increase
increase the TE increase the scan time
If we increase the TE, what will this do to the effect on detail/spatial resoultion?
unchanged
If we increase the TE, what will this do to the SAR?
unchanged!
If we increase the TE, what will this do to the T2 weighting??
it increases the t2 weighting and decrease the T1 weighting
When we increase the field of view, what does this do to the SNR?
it increases the SNR
increased FOV increased SNR
When we increase the field of view, what does this do to the area of coverage??
it increases the coverage area (obviously)
When we increase the field of view, what does this do to the effect on detail?
when you increase the FOV it DECREASES the spatial resolution
If we decrease the TE, what will this do to the T2 weighting??
it will decrease the T2 weighting and increase the T1 weighting
When we increase the field of view, what does this do to the SAR?
unchanged
When we decrease the field of view, what does this do to the SNR?
decreased FOV decreased SNR
If we increase the number of exitations ( NEX), what affect does this have on the SNR?
increased NEX increased SNR
If we increase the number of exitations ( NEX), what affect does this have on the scan time?
Increased NEX, increased scan time
If we increase the number of exitations ( NEX), what affect does this have on the spatial resolution?
nothing, its unchanged
If we increase the number of exitations, what does this do to the SAR?
increases the SAR
If we decrease the number of exitations ( NEX), what affect does this have on the SNR?
decreased NEX, decreased SNR
If we increase the number of exitations ( NEX), what affect would this have on what the image loos like?
It can have more motion artifact
If we increase the number of echo train length, what affect does this have on the SNR?
if we increase the ETL, it decreases SNR
If we increase the number of echo train length, what affect does this have on the scan time?
increased ETL = decreased scan time
If we increase the number of echo train length, what affect does this have on the SAR?
increased SAR with increased ETL
What is a downfall for increasing the ETL?
possibly more blurring in the image.
If we increase the TI (inversion time) , what affect does this have on the SNR?
increased TI, decreased SNR
If we increase the TI (inversion time) , what affect does this have on the scan time?
increased TI, increased time due to the increased TR required
What affect does increasing the TI have on the spatial resolution or SAR?
none- no change
When we increase the flip angle, what does that do to the SNR?
increased flip angle, increased SNR
When we increase the flip angle, what does that do to the sar?
increased SAR increased flip angle
When we decrease the flip angle, waht does that do to the SNR?
decreased flip angle, decrease SNR.
When we decrease the flip angle, what does that do to the sar?
decreased flip angle decreased sar
When we increase the flip angle what does this do to the susceptibility?
increased flip angle, decreased susceptibility
Does changing the flip angle have any effect on the scan time or detail of exam?
no unchanged
If we increase the phase matrix, what effect does that have on SNR?
increased phase matrix, DECREASED SNR
If we increase the phase matrix, what effect does that have on scan time??
increased phase matrix, increased scan time.
If we increase the phase matrix, what effect does that have on the detail / spatial resolution?
increase phase matrix, increased resolution
If we DECREASE the phase matrix, what effect does that have on SNR?
decreased phase matrix, INCREASED SNR
If we increase the phase matrix, what effect does that have on SAR?
increased matrix increased SAR
If we increase the number of SAT bands, what does this do to the SNR?
the more SAT bands you have, the worse the SNR (decreases)
If we increase the number of SAT bands, what does this do to the scan time?
when we increase the SAT bands, it increases the TR which makes the time go up. so increases.
If we increase the number of SAT bands, what does this do to the effect on detail?
nothing, unchanged
If we increase the number of SAT bands, what does this do to the SAR?
increased SAR with each number of SAT band added
What is a positive oucome of using more Sat bands?
it will decrease the motion/flow artifacts
When we increase our slice thickness, what happens to the SNR?
increased slice thickness, increased SNR
When we increase our slice thickness, what happens to the scan time?
unchanged
When we increase our slice thickness, what happens to the effect on detail?
more slice thickness less spatial resolution
When we increase our slice thickness, what happens to the SAR
unchanged
When we increase our number of slices, what effect does this have on the SNR?
unchanged
When we increase our number of slices, what effect does this have on the scan time?
increased due to the increased need for TR.
When we increase our number of slices, what effect does this have on the detail?
unchanged
When we increase our number of slices, what effect does this have on the SAR?
increased SAR because its increased TR/number of slices.
Will increasing the TR INCREASE scan time or DECREASE scan time?
increasing TR will increase scan time.
Will increasing the number of slices INCREASE or decrease the scan time?
increasing the number of slices will increase the scan time
Will increasing the NEX increase or decrease the scan time?
increasing NEX will increase scan time
Will decreasing the ETL increase or decrease scan time?
decreasing the ETL will increase scan time
If we disable half scan feature, what affect will this have on scan time ( increase it or decrease)
disabling half scan will increase scan time
If we decrease the TR what effect will this have on scan time?
decreasing TR decreases scan time
If we decrease the number of slices, what affect will this have on the scan time?
decreased slices, decreased scan time
If we enable half scan, what will this do to the scan time?
enabling half scan will decrease the scan time
if we increase the “ipat or grappa), what affect will this have on scan time?
increasing IPAT decreases scan time
If we decrease the phase matrix, what affect does this have on the scan time?
decreased scan time