Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
17 Cards in this Set
- Front
- Back
|
How to calculate available imaging time in a cardiac MR
|
(effective TR) - (delay and trigger window)
effective tr = 60,000 / heart rate minus delay plus trigger window (trigger window is percent of effective TR) |
|
|
Formula to calculate effective TR in a cardiac MR
|
60,000 / heart rate
*(60 seconds a minute 1000 milliseconds a second) |
|
|
FOV and SNR
|
Reducing the FOV decreases SnR by a factor of the FOV ².
|
|
|
Bandwidth and SnR
|
Decreasing BW by a factor of 2 increases SnR by ² (square root)
|
|
|
NSA / NEX and SnR
|
SnR increase is calculated by the square root of the increase
|
|
|
Voxel volume
|
(Pixel area) (slice thickness)
*answer is cubic ³ |
|
|
Pixel area
|
Multiply phase pixel size by frequency pixel size = pixel area (squared)
|
|
|
Frequency dimension of a pixel
|
FOV ÷ frequency matrix
|
|
|
Phase dimension of pixel
|
FOV ÷ Phase matrix
|
|
|
Calculate pixel size
|
FOV ÷ Matrix
|
|
|
Scan time formula for a fast spin echo
|
(TR) (phase matrix) (nex) ÷ ETL
|
|
|
1mm is how many cm?
|
0.1 cm
|
|
|
1cm is how many mm?
|
10 mm
|
|
|
Scan time formula for spin echo
|
(TR) (phase matrix) (NSA)
|
|
|
1 second is ? Milliseconds?
|
1 second = 1000 milliseconds
|
|
|
Convert milliseconds to seconds
|
Divide by 1000
|
|
|
3D Gradient echo scan time formula
|
(TR) (phase) (NSA or Nex) (# of slices)
|
