Releasing the mouse button then connects the start and end points and displays the text info window with a summary of the statistics of the intensity values for each image volume loaded into rview, within this 2D region. These include the mean and standard deviation (SD) together with the min and max:
This can then be copied and pasted into other windows applications using 'CTRL-C'
Notes about values:
The statistics are created 'on the fly' by transforming the ROI points in the display plane co-ordinates into each of the image spaces (using the appropriate volume transformations determined by the display window and the registration transformations for each data set) and interpolating the value at each point using tri-linear interpolation. The screen pixels within the ROI are
oversampled at a fine resolution (around 0.1mm) and the statistics are then evaluated over this finely sampled grid of values. Since the ROI values are interpolated from the 3D data. the effective 'thickness' of the 2D ROI is dependent on the spatial resolution and point spread function of the specific volume dataset (in each of its axes), AND the orientation of the display plane with respect to the different axes of the 3D data volume.
Clear ROI
To clear the current ROI select 'Clear ROI'
Save ROI
This prompts the user for a rview setup filename and then saves the ROI points in this setup file (other setup values such as the current images loaded and display layout are not saved in this setup file). These can then be loaded into rview again later by simply dragging and dropping the setup file into rview: The ROI will then be placed in the same 3D location over the currently loaded 3D data volumes. Alternatively 'Save View' can be used to save everything describing the state of rview including the currently marked ROI.