@Ebgirl - if you have folders for your CT & MRI on your computer desk top, you can select files from each folder to upload here using the underlined up arrow icon at the top of the text box where you type your next post.
Since some of us here aren’t good at reading slices, many members have used RadiAnt Viewer or other 3D slicer software to convert their CTs into 3D. I assume this also works for MRIs but I’m not certain.
Here’s a link to an older post describing how to do the conversion: