Hi,
A CT scan is a kind of an Xray in simple terms. It will only show an abdominal mass, a CT guided biopsy will however be helpful in diagnosing if it is a benign tumor or a malignant one. Hope this helps!
Not that you might have cancer as 95% of all masses are benign but I would like to suggest that you go to the Ovarian Carcer forum, or to the Ovarian cyst forum, there you will get lots of info from many ladies.