For some reason I can’t adjust the contrast in my Dicom images since I upgraded to the latest slicer, is this an issue for anyone else?
With so little information it is impossible to know the answer, but a hint may be to use the mouse mode toolbar:
If this doesn’t solve your issue then it would be useful if you gave more information. From what Slicer version to what version? How did you want to adjust contrast, what you did, what you expected, what happened instead?
Ha…I didn’t even know that existed, thank you, works a treat!! 
