Acceleration Factor Rate
Compare a supplied full acquisition with accelerated readout plus explicit calibration and fixed overhead; effective acceleration can be below one.
Description
Nominal acceleration can overstate time saved when calibration and fixed overhead contribute to the accelerated scan.
Nominal acceleration can overstate time saved when calibration and fixed overhead contribute to the accelerated scan. Effective acceleration compares full durations.
The tool returns acceleratedTotalSeconds (accelerated total seconds); effectiveAcceleration (effective acceleration); savedSeconds (saved seconds). Input measurements and model parameters are supplied by the caller; the tool computes the stated summary rather than acquiring those measurements.
When to use Acceleration Factor Rate
Use Acceleration Factor Rate when you already have fullAcquisitionSeconds, acceleratedReadoutSeconds, calibrationSeconds, fixedOverheadSeconds and want acceleratedTotalSeconds, effectiveAcceleration, savedSeconds. This is useful for checking a supplied calculation, documenting a measurement convention, or comparing observations prepared on the same basis.
How to use Acceleration Factor Rate and understand its results
- Enter fullAcquisitionSeconds, acceleratedReadoutSeconds, calibrationSeconds, fixedOverheadSeconds 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 acceleratedTotalSeconds, effectiveAcceleration, savedSeconds. 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 |
|---|---|---|---|
| fullAcquisitionSeconds | Full acquisition seconds | number | Required |
| acceleratedReadoutSeconds | Accelerated readout seconds | number | Required |
| calibrationSeconds | Calibration seconds | number | Required |
| fixedOverheadSeconds | Fixed overhead seconds | number | Required |
Use positive full and accelerated-readout durations and nonnegative overheads. Return total, ratio and signed seconds saved.
acceleratedTotal = readout+calibration+overhead; effective = fullDuration/acceleratedTotal The symbols refer to the supplied quantities or generated values described above; unit conversions and comparison boundaries follow the stated implementation.
{
"input": {
"fullAcquisitionSeconds": 100,
"acceleratedReadoutSeconds": 20,
"calibrationSeconds": 5,
"fixedOverheadSeconds": 5
},
"output": {
"acceleratedTotalSeconds": 30,
"effectiveAcceleration": 3.3333333333333335,
"savedSeconds": 70
}
}Limitations and assumptions
An effective ratio below one and negative savings are retained. No timing components or comparison baseline are inferred.
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
GRAPPA Acceleration: Count unique regularly subsampled phase lines plus a contiguous ACS interval, avoiding double counting; GRAPPA kernel fitting and reconstruction are not performed. Echo Train Length: Allocate required phase lines into bounded echo trains, retaining a short final shot; echo weighting, k-space ordering and sequence-specific ETL definitions are external.
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
- GRAPPA Acceleration
Count unique regularly subsampled phase lines plus a contiguous ACS interval, avoiding double counting; GRAPPA kernel fitting and reconstruction are not performed.
- Echo Train Length
Allocate required phase lines into bounded echo trains, retaining a short final shot; echo weighting, k-space ordering and sequence-specific ETL definitions are external.