OCTA Avascular Area
Measure zero-flow area and fraction from a binary OCTA flow mask.
Description
A binary OCTA mask marks zero-valued pixels as avascular for this area tally.
A binary OCTA mask marks zero-valued pixels as avascular for this area tally. Pixel pitch converts counts to area.1
Measure zero-flow area and fraction from a binary OCTA flow mask.
When to use OCTA Avascular Area
Use this tool to measure zero-flow area and fraction from a binary OCTA flow mask.
Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
How to use OCTA Avascular Area and understand its results
- Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
- Enter binaryFlowMask, imageWidthPixels, pixelPitchMicrometers using the field table and calculation rules, then run the tool.
- Read avascularPixelCount, avascularAreaSquareMillimeters, avascularFraction. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| binaryFlowMask | Binary OCTA flow mask | list of number | Required |
| imageWidthPixels | Image width | integer; minimum: 1 | Required |
| pixelPitchMicrometers | Pixel pitch (µm) | number; minimum: 0 | Required |
Enter nonempty zero/one mask, positive integer image width and nonnegative pitch. Require complete rows; return zero count, area and fraction.
area_mm²=zeroCount×pitch_µm²/1e6; fraction=zeroCount/pixelCount Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| avascularPixelCount | Avascular pixel count | integer; minimum: 0 |
| avascularAreaSquareMillimeters | Avascular area (mm²) | number; minimum: 0 |
| avascularFraction | Avascular fraction | number; minimum: 0; maximum: 1 |
{
"input": {
"binaryFlowMask": [
0,
1,
0,
1
],
"imageWidthPixels": 2,
"pixelPitchMicrometers": 10
},
"output": {
"avascularPixelCount": 2,
"avascularAreaSquareMillimeters": 0.0002,
"avascularFraction": 0.5
}
}Limitations and assumptions
No flow estimation, anatomical segmentation or clinical diagnosis is performed. All zero pixels count, including background or artifacts.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use OCT Axial Resolution: Estimate Gaussian-spectrum OCT axial resolution in air and sample. For a complementary task, use Photoacoustic Hemoglobin Contrast: Unmix two-wavelength photoacoustic signals into hemoglobin contributions and saturation.
References
-
OCTA Avascular Area — tool.io
Similar or alternative tools
- OCT Axial Resolution
Estimate Gaussian-spectrum OCT axial resolution in air and sample.
- Photoacoustic Hemoglobin Contrast
Unmix two-wavelength photoacoustic signals into hemoglobin contributions and saturation.