Centiloid Scale
Convert cortex/reference uptake to a Centiloid scale using externally validated pipeline-specific 0/100 SUVR anchors; negative and above-100 results are not clipped.
Description
The Centiloid scale linearly maps calibrated uptake-ratio anchors to zero and 100.
The Centiloid scale linearly maps calibrated uptake-ratio anchors to zero and 100. The mapping depends on the tracer and processing calibration represented by those anchors.
The tool returns suvr (suvr); centiloidValue (centiloid value). Input measurements and model parameters are supplied by the caller; the tool computes the stated summary rather than acquiring those measurements.
When to use Centiloid Scale
Use Centiloid Scale when you already have corticalUptake, referenceUptake, zeroAnchorSuvr, hundredAnchorSuvr and want suvr, centiloidValue. This is useful for checking a supplied calculation, documenting a measurement convention, or comparing observations prepared on the same basis.
How to use Centiloid Scale and understand its results
- Enter corticalUptake, referenceUptake, zeroAnchorSuvr, hundredAnchorSuvr 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 suvr, centiloidValue. 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 |
|---|---|---|---|
| corticalUptake | Cortical uptake | number | Required |
| referenceUptake | Reference uptake | number | Required |
| zeroAnchorSuvr | Zero anchor suvr | number | Required |
| hundredAnchorSuvr | Hundred anchor suvr | number | Required |
Use nonnegative cortical uptake, positive reference uptake and positive zero anchor, with the hundred anchor strictly greater.
SUVR = cortical/reference; Centiloid = 100×(SUVR−zeroAnchor)/(hundredAnchor−zeroAnchor) The symbols refer to the supplied quantities or generated values described above; unit conversions and comparison boundaries follow the stated implementation.
{
"input": {
"corticalUptake": 15,
"referenceUptake": 10,
"zeroAnchorSuvr": 1,
"hundredAnchorSuvr": 2
},
"output": {
"suvr": 1.5,
"centiloidValue": 50
}
}Limitations and assumptions
Values are not clipped to 0–100. The tool does not supply validated anchors, process scans or diagnose amyloid positivity.
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
ATN Classification Tool: Label supplied A/T/N biomarkers with caller assay thresholds and direction, inclusive at threshold; profiles are descriptive research categories, not a diagnosis or disease stage. Neuromelanin Contrast: Compute neuromelanin-sensitive ROI/reference contrast and CNR using reference sample SD; scanner sequence and ROI selection are external, and contrast is not neuron density.
Methodological background: The Centiloid Project: Standardizing Quantitative Amyloid Plaque Estimation by PET.1
References
-
The Centiloid Project: Standardizing Quantitative Amyloid Plaque Estimation by PET — Klunk et al.; Alzheimer’s & Dementia
Similar or alternative tools
- ATN Classification Tool
Label supplied A/T/N biomarkers with caller assay thresholds and direction, inclusive at threshold; profiles are descriptive research categories, not a diagnosis or disease stage.
- Neuromelanin Contrast
Compute neuromelanin-sensitive ROI/reference contrast and CNR using reference sample SD; scanner sequence and ROI selection are external, and contrast is not neuron density.