I know that due to having several surgeries and a lot of dense scar tissue, I have had cyst show up on CT scans that did not show up on a TVUS. I have a bit of a different situation though because I have Ovarian Remnant Syndrome (ORS) so I just have small ovarian cells that eventually regenerate into an ovary. I also had to have my ureter tube reinserted into my bladder, so when my ovary regenerates, it is usually behind the ureter tube. This time, however, the CT did not show anything, but the TVUS showed a 5cm cyst. For me it is just trial and error. Typically though, TVUS are better for detecting ovarian cysts. If the CT showed a cyst, it may be possible that it ruptured. That can cause horrible pain. If you feel like you still have a cyst, ask for a follow up CT scan. Keep in mind that the squeaky wheel gets the oil. Please keep us posted on how you are doing and what you find out.
Ulrasounds are very effective screening tests that are better for you, too, since no radiation is involved.
There is a lot of outcry that too many CT tests are being needlessly ordered. They are expensive, use radiation...and it seems to a skeptic like me that doctors order them to help pay for their expensive CT machines and whether they could get confirmation that insurance will cover the cost...money-making decisions rather than what is best for the patient.
What really infuriates me is all the times I've read here of women getting CTs...then getting referred for ultrasounds. The ultrasound would have been enough.
CT scans do give an impressive visualization, but talented radioligists do a fine interpretation of ultrasound results with a lot less harm to their patients.