Cyst in the ovaries are commonly found on CTs obtained for various reasons including pelvic pain. Cysts can vary in size from less than 1 centimeter to large masses that fill the pelvis. They are also a common normal finding as smaller cysts less than 2.5 cm are found in the ovaries and are related to reproduction and formation of an ovum. On CT, cysts are seen as fluid filled or complex lesions in the ovaries.
Ct does not fully evaluate cysts. Pelvic ultrasound is the best test to closely look at the contents of a cyst and to say what kind of cyst it is. In reproductive age women, the majority of cysts will be benign and related to ovulation and normal physiology. Sometimes cysts can be from endometriosis or even tumors or growths. In many cases, pelvic ultrasound is able to distinguish the various cyst types.
CT may therefore detect a cyst, but will not in many cases tell what kind of cyst it is. A pelvic ultrasound is needed. Most smaller cysts in reproductive age women are benign cysts. Cysts in post menopausal women become more concerning and should be fully evaluated with pelvic ultrasound.
Cysts that are large, say greater then 5 cm, in post menopausal women, have internal complex parts like solid nodules or thick septations become more concerning. These are not always seen on CT however, and therefore cysts need further evaluation on pelvic ultrasound. These more complex and larger cysts raise greater concern for cancerous growths.
Cysts that are accompanied by fluid can represent some leakage which can sometimes be associated with pain. Additionally, some cysts can rupture and bleed, occasionally causing significant bleeding. Fluid can also be seen with cancer of the ovaries. In these cases, the cysts are larger, more complex and there can be signs of the spread of the cancer throughout the abdomen and pelvis. A large swollen ovary with a cyst can be twisted or torsed.
Frequently, the radiologist will offer his opinion on what needs to be done next and whether there are any associated abnormalities suspected like rupture, cancer, or twisting of the ovary. In many cases, a pelvic ultrasound will be suggested which gives a close look at the ovary and the cysts. The ultrasound can also better evaluate for the kind of cyst and whether there are any findings of ovarian twisting or torsion. Your doctor will also use your clinical presentation as to best direct the workup of a cyst found on CT.