SIENA Brain Atrophy Rate Calculator
Actual independently SIENA processed PBVC annual arithmetic loss positive=−PBVC/years. Does not run SIENA registration/segmentation or compound volume endpoint ratio. Actual independently matched observations/units and protocol, not diagnosis, causal mechanism, clinical decision or validated individual prediction.
Description
An annualized SIENA percentage change starts with the output of an independently completed image-analysis pipeline.
An annualized SIENA percentage change starts with the output of an independently completed image-analysis pipeline.1
This tool negates and divides that supplied percentage by elapsed years so volume loss has a positive sign.
When to use SIENA Brain Atrophy Rate Calculator
This tool negates and divides that supplied percentage by elapsed years so volume loss has a positive sign.
How to use SIENA Brain Atrophy Rate Calculator and how it works
- Prepare siiena signed percentage brain volume change, elapsed years, using the input definitions and matching units below.
- Enter the required fields and run SIENA Brain Atrophy Rate Calculator.
- Read result.value using the units, signs and ordering explained below.
- Correct any rejected inputs and rerun; interpret the result within the stated model and its assumptions.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| actualSiienaSignedPercentageBrainVolumeChange | Actual Siiena Signed Percentage Brain Volume Change. Use the units and matching context stated in the calculation below. | number | Required; finite; other constraints below |
| actualElapsedYears | Actual Elapsed Years. Use the units and matching context stated in the calculation below. | number | Required; strictly positive; finite; other constraints below |
Accept finite independently processed signed SIENA percentage brain-volume change and positive elapsed years. Return negative PBVC divided by years as arithmetic annual percentage loss. An increase yields a negative loss rate; registration, segmentation and compounded endpoint change are not performed.
annualLossPercent=-signedPbvc/elapsedYears Apply the input ordering, units and branch conditions stated above.
| Output field | Meaning | Value type |
|---|---|---|
| result | Object containing the calculated or selected fields below. | object |
| result.value | Arithmetic annual percentage loss, positive for loss and negative for increase. | number |
{
"input": {
"actualSiienaSignedPercentageBrainVolumeChange": -2,
"actualElapsedYears": 2
},
"output": {
"result": {
"value": 1
}
}
}Limitations and assumptions
The calculation uses the supplied observations and model inputs. It does not collect measurements, select a reference population or coefficient, or establish that the model applies to the actual case. The stated branch conditions and output units remain part of the result.
All fields require explicit values. Unexpected fields, wrong types, nonfinite numbers and sparse arrays are rejected. Alignment, bounds and supported-token rules are explained above; extremely large inputs or nonfinite results can also fail. Input errors differ from successful false comparisons, unavailable-domain flags and empty match lists.
Alternative or Complementary methods
Use BBSI Brain Atrophy Rate Calculator for a complementary operation: A BBSI annual loss rate uses an independently estimated signed volume loss, baseline volume and elapsed years.
Use Brain Maintenance Index Calculator for a complementary operation: Brain-maintenance indices depend on independently chosen measures, transformations and comparison context.
References
-
SIENA Brain Atrophy Rate Calculator — tool.io
Similar or alternative tools
- BBSI Brain Atrophy Rate Calculator
A BBSI annual loss rate uses an independently estimated signed volume loss, baseline volume and elapsed years.
- Brain Maintenance Index Calculator
Brain-maintenance indices depend on independently chosen measures, transformations and comparison context.