Would a CT Scan with contrast show if a muscle repair that was done during TT is blown or not?

Generally speaking, careful physical examination is the best "test" when it comes to making a diagnosis in situations like this. Occasionally, imaging studies such as  ultrasounds or CT scans may be helpful.  Best wishes.

A physical exam might suffice.  If there is a palpable gap between the pair of abdominal muscle, which runs from the breastbone down to the area above the pubis, there is diastasis recti or weakness of the abdominal muscle. 

Good luck and best wishes. 

It should pick it up if the muscle repair has come apart unless it is in a very small area. The best first step if you think you have ruptured the repair is see your surgeon to be examined. Best of luck!