Repetition Time TR
Budget sequential nonoverlapping slice blocks plus recovery time within TR; simultaneous or interleaved waveform schedules are not inferred.
Description
A sequential slice-block timing budget sums occupied durations and a recovery delay.
A sequential slice-block timing budget sums occupied durations and a recovery delay. Configured TR must contain the whole schedule.
The tool returns minimumTrMs (minimum tr ms); trSlackMs (tr slack ms); fitsConfiguredTr (fits configured tr). Input measurements and model parameters are supplied by the caller; the tool computes the stated summary rather than acquiring those measurements.
When to use Repetition Time TR
Use Repetition Time TR when you already have sliceBlockDurationsMs, recoveryDelayMs, configuredTrMs and want minimumTrMs, trSlackMs, fitsConfiguredTr. This is useful for checking a supplied calculation, documenting a measurement convention, or comparing observations prepared on the same basis.
How to use Repetition Time TR and understand its results
- Enter sliceBlockDurationsMs, recoveryDelayMs, configuredTrMs 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 minimumTrMs, trSlackMs, fitsConfiguredTr. 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 |
|---|---|---|---|
| sliceBlockDurationsMs | Slice block durations ms | list of number | Required |
| recoveryDelayMs | Recovery delay ms | number | Required |
| configuredTrMs | Configured tr ms | number | Required |
Use a nonempty list of positive durations, nonnegative recovery delay and positive TR. A zero slack passes.
minimumTR = ΣsliceBlockDurations+recoveryDelay; slack = configuredTR−minimumTR The symbols refer to the supplied quantities or generated values described above; unit conversions and comparison boundaries follow the stated implementation.
{
"input": {
"sliceBlockDurationsMs": [
10,
20,
10
],
"recoveryDelayMs": 60,
"configuredTrMs": 100
},
"output": {
"minimumTrMs": 100,
"trSlackMs": 0,
"fitsConfiguredTr": true
}
}Limitations and assumptions
Blocks are assumed nonoverlapping. Concurrent operations, hardware constraints and actual sequence execution are not 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
Echo Spacing: Budget echo-center spacing from explicitly nonoverlapping readout, turnaround and settling intervals; waveform overlaps require a different timing model. 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: RAD229: MRI signal and sequence lecture notes.1
References
-
RAD229: MRI signal and sequence lecture notes — Brian Hargreaves and colleagues, Stanford University
Similar or alternative tools
- Echo Spacing
Budget echo-center spacing from explicitly nonoverlapping readout, turnaround and settling intervals; waveform overlaps require a different timing model.
- 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.