Statistics of VOI Pixel Values

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Statistics of VOI Pixel Values

The  statistics menu offers various types of calculations


Selected Statistics: Applies the VOIs to the current image and shows the results of the configured statistics on the Statistics Viewer panel.

Default Statistics: Applies the VOIs to the current image and shows the default statistics (which don't require too much calculation time).

Histograms: Calculates and shows a pixel value histogram per VOI illustrating the value distribution.

Textures: Quantifies the variability of the pixel intensities within a structure such as a tumor. With this selection 25 texture features within the VOIs will be estimated.

Multi-Statistics: Calculates the Default Statistics for all loaded images and shows the results on one panel per image. The outcome can then easily be merged into an aggregate.

Multi-Histograms: Calculates the VOI histograms for all loaded images and shows them on one panel per image.

File-Statistics: Performs the Default Statistics for a list of files image and saves the resulting statistics in a file. This procedure requires explicit image loading and is most useful when the images are in a normal (e.g. MNI) space, so that a standard set of VOIs can be applied.

Pixel Dump: Extracts the VOI pixel values in the selected image and saves them together with the pixel coordinates in a file. This  procedure gives the user the full raw data and allows him implementing his own statistical analysis.

File-Pixel Dump: Performs the Pixel Dump for a list of files.

VOIs used for Statistics

The following VOIs are considered in the statistics calculations described above:

All contour VOIs on the List tab.

The VOI named Group which consists of the union of all contour VOIs selected on the Group tab.

If on the Template tabs Atlas or Mask is active, the corresponding VOIs are also considered. Please enable the Ovr box to see these VOIs in the overlay.

If a masking operation is configured on the Atlas or Mask sub-tab, it is applied to the contour VOIs during the statistics. Please enable the Fill ROI box to verify the actual coverage of the masked contour VOIs.