I’m trying to create a mask for registration of MRI and CT pelvis scans using scissors in segment editor. It works perfectly for CT but when I draw the same free-form area on the MRI the mask only goes half through the space that I drew as shown in the images. I tried other tools like draw and paint but they also can fill up to the lower half of the MRI scan and not the upper half. What can I do to solve this issue ? Thank you.