ROI metrics and measurement style
Read ROI dimensions and statistics, and adjust measurement appearance.
On this page
Dimensions and area
Dimensions use mm and area uses mm². Ellipse dimensions are diameters. Area describes the whole geometric outline; it is not valid pixel count multiplied by pixel area.
Read statistics
Mean is the average, SD the population standard deviation, Min / Max the extremes and N valid pixel count. Values use modality pixels, resampled for MPR, rather than screen brightness.
Valid samples
Intensity statistics use valid pixel centers inside the outline. A partially outside ROI still samples its overlap with the image; out-of-image and non-finite values are excluded. If no valid samples remain, the card shows No valid pixels, not zero; moving it back restores statistics. Area and dimensions always describe the full outline. CT uses HU; PET uses an available data unit.
Choose statistics
Toggle fields in Settings → ROI statistics. Width and height share a toggle and a row with area. Hiding fields does not change calculations.
Colors and line styles
In Settings → Measurements and annotations, choose drawing / editing and completed colors, solid / dashed lines, width and font size. Arrows and CPR paths share the drawing and editing style. Completed measurements and CPR paths are gold by default, while arrows are light purple. To use one color, enable Use shared completed color under Arrow annotations. Other CPR paths use a subdued completed color. Changes apply immediately. Image zoom does not enlarge text or line widths. Measurement precision defaults to 2 decimal places, with integer, 1, 2 or 3 decimals available. Length, angle, ROI dimensions/area/intensity, VOI volume/statistics, MTF and water QA results update together. Pixel/voxel counts stay integers; calculations and workspace data remain unrounded.
Save and restore
Styles save locally. Restore defaults resets only the current settings category. Save measurement objects separately in a workspace; saving a style does not save results.