I am trying to understand how the manual min/max window level and threshold in the volumes tab works. I need to be able to convert back from pixel intensity to Hounsfield units. I use screen capture to obtain a png image and I save the nifti data to know the Hounsfield units. When I plot (using Matlab) the relationship between the Hounsfield units and pixel intensity, I don’t see any relationship to the window level. If there is a simple way to convert from png back to Hounsfield units, please let me know.