Lesion Volume
Integrate lesion voxel fractions using anisotropic voxel dimensions; segmentation and partial-volume probabilities must be supplied.
Description
Partial-volume lesion fractions represent how much of each voxel belongs to a lesion.
Partial-volume lesion fractions represent how much of each voxel belongs to a lesion. Summing fractions gives an effective voxel count rather than a binary count.
The tool returns effectiveVoxelCount (effective voxel count); lesionVolumeMm3 (lesion volume mm3); lesionVolumeMl (lesion volume ml). Input measurements and model parameters are supplied by the caller; the tool computes the stated summary rather than acquiring those measurements.
When to use Lesion Volume
Use Lesion Volume when you already have lesionFractions, voxelDimensionsMm and want effectiveVoxelCount, lesionVolumeMm3, lesionVolumeMl. This is useful for checking a supplied calculation, documenting a measurement convention, or comparing observations prepared on the same basis.
How to use Lesion Volume and understand its results
- Enter lesionFractions, voxelDimensionsMm 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 effectiveVoxelCount, lesionVolumeMm3, lesionVolumeMl. 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 |
|---|---|---|---|
| lesionFractions | Lesion fractions | list of number | Required |
| voxelDimensionsMm | Voxel dimensions mm | list of number | Required |
Use a nonempty fraction list in [0,1] and three positive voxel dimensions in mm.
volumeMm³ = Σfractions × dx×dy×dz; volumeMl = volumeMm³/1000 The symbols refer to the supplied quantities or generated values described above; unit conversions and comparison boundaries follow the stated implementation.
{
"input": {
"lesionFractions": [
0,
0.5,
1
],
"voxelDimensionsMm": [
2,
2,
3
]
},
"output": {
"effectiveVoxelCount": 1.5,
"lesionVolumeMm3": 18,
"lesionVolumeMl": 0.018
}
}Limitations and assumptions
The fractions and dimensions are supplied; lesion segmentation, uncertainty and spatial correspondence are not verified.
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
Infarct Volume ABC/2: Estimate ABC/2 lesion volume using caller-measured perpendicular diameters and fractional slice weights; irregular infarcts can violate the ellipsoidal approximation. Resel Count: Estimate the volume resel term R3 from a fractional search mask and axis-aligned anisotropic FWHM; boundary and lower-dimensional resel terms are not included.
Methodological background: NIfTI coordinates and affine transformations.1
References
-
NIfTI coordinates and affine transformations — Robert W. Cox; National Institute of Mental Health
Similar or alternative tools
- Infarct Volume ABC/2
Estimate ABC/2 lesion volume using caller-measured perpendicular diameters and fractional slice weights; irregular infarcts can violate the ellipsoidal approximation.
- Resel Count
Estimate the volume resel term R3 from a fractional search mask and axis-aligned anisotropic FWHM; boundary and lower-dimensional resel terms are not included.