I downloaded the beta version of memoQ 8.1 and had a look at how it handles tracked changes in Studio projects. They are actually visible and editable. Didn't try to import the reviewed file in Studio. Just wanted to look at how this feature was implemented.
BTW: To install this beta version I had to install tons of MS stuff. I think the extra software for a Java app is only a fraction of this MS stuff.
Here's a screenshot of memoQ 8.1 showing a segment of a Studio file with tracked changes: