BBSI Brain Atrophy Rate Calculator

Actual independently BBSI estimated signed volume loss/baseline/years annual percent. Does not perform boundary integral registration, or equate with SIENAPBVC method. Actual independently matched observations/units and protocol, not diagnosis, causal mechanism, clinical decision or validated individual prediction.

Description

A BBSI annual loss rate uses an independently estimated signed volume loss, baseline volume and elapsed years.

A BBSI annual loss rate uses an independently estimated signed volume loss, baseline volume and elapsed years.^[1]

This tool calculates a percentage per year without performing boundary-shift registration or equating the method with SIENA.

When to use BBSI Brain Atrophy Rate Calculator

This tool calculates a percentage per year without performing boundary-shift registration or equating the method with SIENA.

How to use BBSI Brain Atrophy Rate Calculator and how it works

Prepare independent bbsi volume loss, independent baseline brain volume, elapsed years, using the input definitions and matching units below.
Enter the required fields and run BBSI 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
actualIndependentBbsiVolumeLoss	Actual Independent Bbsi Volume Loss. Use the units and matching context stated in the calculation below.	number	Required; finite; other constraints below
actualIndependentBaselineBrainVolume	Actual Independent Baseline Brain Volume. Use the units and matching context stated in the calculation below.	number	Required; strictly positive; 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

Require positive independently established baseline brain volume and elapsed years, with finite independently estimated signed BBSI volume loss. Return 100*loss/baseline/years as annual percentage loss. Loss and baseline must share a volume unit; signed increases remain negative and the image-analysis pipeline is not run.

annualLossPercent=100*signedBbsiVolumeLoss/baselineVolume/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

json

{
  "input": {
    "actualIndependentBbsiVolumeLoss": 2,
    "actualIndependentBaselineBrainVolume": 100,
    "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 SIENA Brain Atrophy Rate Calculator for a complementary operation: An annualized SIENA percentage change starts with the output of an independently completed image-analysis pipeline.

Use Brain Maintenance Index Calculator for a complementary operation: Brain-maintenance indices depend on independently chosen measures, transformations and comparison context.

References

BBSI Brain Atrophy Rate Calculator — tool.io

Similar or alternative tools

SIENA Brain Atrophy Rate Calculator
An annualized SIENA percentage change starts with the output of an independently completed image-analysis pipeline.
Brain Maintenance Index Calculator
Brain-maintenance indices depend on independently chosen measures, transformations and comparison context.