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