Simultaneous Multi-Slice Leakage
Audit leakage fractions from measured source-to-target slice transfer magnitudes; source rows require consistent calibration and this is not a slice-unmixing algorithm.
Description
A measured slice-transfer matrix reports how source-slice signal appears in reconstructed target slices.
A measured slice-transfer matrix reports how source-slice signal appears in reconstructed target slices. Off-target fraction summarizes leakage relative to each source row’s total.
The tool returns offTargetFractions (off target fractions); maximumOffTargetFraction (maximum off target fraction). Input measurements and model parameters are supplied by the caller; the tool computes the stated summary rather than acquiring those measurements.
When to use Simultaneous Multi-Slice Leakage
Use Simultaneous Multi-Slice Leakage when you already have measuredTransferMagnitudes and want offTargetFractions, maximumOffTargetFraction. This is useful for checking a supplied calculation, documenting a measurement convention, or comparing observations prepared on the same basis.
How to use Simultaneous Multi-Slice Leakage and understand its results
- Enter measuredTransferMagnitudes using the field table below. Match the units, ordering and data boundaries described in the calculation.
- Run the tool after checking the stated bounds and matching paired observations or categories. A malformed request gives a tool error rather than a usable measurement.
- Read offTargetFractions, maximumOffTargetFraction. Use the calculation and interpretation below to distinguish amounts, ratios, signs and decision flags where applicable.
- Review the supplied parameters and assumptions before using the result in a report or comparing it with another observation.
| Input field | Meaning | Value type and bounds | Requirement |
|---|---|---|---|
| measuredTransferMagnitudes | Measured transfer magnitudes | list of list of number | Required |
Require a nonnegative square matrix with positive sum in every source row. Return each row fraction and their maximum.
offTargetFraction[row] = (rowSum−diagonalEntry)/rowSum The symbols refer to the supplied quantities or generated values described above; unit conversions and comparison boundaries follow the stated implementation.
{
"input": {
"measuredTransferMagnitudes": [
[
10,
1
],
[
2,
10
]
]
},
"output": {
"offTargetFractions": [
0.09090909090909091,
0.16666666666666666
],
"maximumOffTargetFraction": 0.16666666666666666
}
}Limitations and assumptions
Rows are sources and columns targets. Transfer magnitudes are not squared into powers, and no acquisition or reconstruction is simulated.
Numerical inputs must be finite. The tool checks its declared input shape and calculation constraints; those checks do not verify the quality, calibration or representativeness of the supplied observations.
Alternative or Complementary methods
SMS Multiband Factor: Plan spatially interleaved simultaneous-slice groups and retain smaller tail groups; CAIPI shifts, RF peak power and sequence timing are external. SENSE Acceleration: Assess real-valued two-coil/two-alias SENSE conditioning through SᵀΨ⁻¹S and geometry factors; this is not general complex-coil image reconstruction.
Methodological background: SENSE: sensitivity encoding for fast MRI.1
References
-
SENSE: sensitivity encoding for fast MRI — Pruessmann et al.; Magnetic Resonance in Medicine
Similar or alternative tools
- SMS Multiband Factor
Plan spatially interleaved simultaneous-slice groups and retain smaller tail groups; CAIPI shifts, RF peak power and sequence timing are external.
- SENSE Acceleration
Assess real-valued two-coil/two-alias SENSE conditioning through SᵀΨ⁻¹S and geometry factors; this is not general complex-coil image reconstruction.