Volume Statistics
The Volume Statistics tool calculates grayscale-based statistics for the active volume dataset and generates a histogram of pixel intensities. Statistics can be filtered by mask regions and computed for individual slices or the entire volume.
Accessing the Tool
- Navigate to the Measure tab in the ribbon
- Click the Volume Statistics button in the Statistics section
Overview
Calculate grayscale-based statistics for the active volume dataset and generate a histogram of pixel intensities, with an option to filter data by selecting corresponding masks.
An active volume dataset must be loaded in the project. Mask-based filtering requires at least one mask object.
User Interface
Description
Displays: "Calculate grayscale-based statistics for the active volume dataset and generate a histogram of pixel intensities, with an option to filter data by selecting corresponding masks."
Options
| Control | Description |
|---|---|
| Target | Select the data source for statistics calculation |
| Slice | Choose which slice(s) to analyze |
Target Options
| Option | Description |
|---|---|
| Active volume | Calculate statistics for all pixels in the active volume dataset |
| Active mask | Calculate statistics for pixels within the active mask only |
| Visible masks | Calculate statistics for pixels within the union of all visible masks |
Slice Options
| Option | Description |
|---|---|
| Current sagittal slice | Analyze only the current sagittal slice |
| Current coronal slice | Analyze only the current coronal slice |
| Current axial slice | Analyze only the current axial slice |
| All slices | Analyze the entire volume (default) |
Histogram Display
| Control | Description |
|---|---|
| Y-axis | Linear or Logarithmic scale for the frequency axis |
| Graph type | Bar, Line, or Filled line visualization style |
| Number of bins | Number of histogram bins (range: 10–100,000, default: 128) |
Information Table
Displays context about the analysis:
| Field | Description |
|---|---|
| Volume | Name of the active volume dataset |
| Mask | Name of the mask (if mask filtering is used) |
| Slice | Which slice or "All slices" |
Whole Volume Statistics Table
Displays calculated statistics for the analyzed region:
| Statistic | Description |
|---|---|
| Mean | Average intensity value |
| Median | Middle value when intensities are sorted |
| Standard Deviation | Measure of intensity variation |
| Variance | Square of standard deviation |
| Minimum | Lowest intensity value |
| Maximum | Highest intensity value |
| Sum | Total of all intensity values |
| Voxel Count | Number of voxels analyzed |
| Skewness | Measure of distribution asymmetry |
| Kurtosis | Measure of distribution tail weight |
Per-Mask Statistics Table
When Visible masks target is selected, an additional table shows statistics for each individual visible mask separately.
Workflow
Basic Statistics Calculation
- Ensure a volume dataset is active
- Open the Volume Statistics tool
- Select Active volume as the target
- Choose All slices to analyze the complete volume
- Statistics are calculated and displayed automatically
- The histogram updates to show the intensity distribution
Masked Region Statistics
- Create or activate a mask covering the region of interest
- Open the Volume Statistics tool
- Select Active mask or Visible masks as the target
- Statistics are calculated only for voxels within the mask
Slice-Specific Statistics
- Navigate to the slice of interest
- Open the Volume Statistics tool
- Select the corresponding slice option
- Statistics reflect only that slice's pixel values
Export
Click the Export... button to save results. Export options include:
- CSV file: Tabular statistics data
- PDF Report: Formatted report with statistics, histogram, and optional snapshots
The PDF report includes:
- Analysis settings (target, slice, histogram options)
- Information table
- Statistics table
- Histogram visualization
- Histogram data table
Use Cases
Image Quality Assessment
Analyze mean, standard deviation, and histogram shape to assess image quality and noise levels.
Tissue Characterization
Compare statistics across different masked regions to characterize tissue types.
Threshold Determination
Use histogram visualization and statistics to determine appropriate segmentation thresholds.
Comparative Analysis
Compare statistics between different volumes or time points for longitudinal studies.
Related Tools
- Histogram — Focused histogram visualization without statistics tables
- Volume Similarity Statistics — Compare two volumes
- Mask Statistics — Shape and intensity statistics for masks