Ovarian cancer is challenging to diagnose early, but timely identification significantly improves outcomes. Ultrasound is a primary, non-invasive imaging technique used to visualize the ovaries. It helps medical professionals distinguish between normal ovarian structures and those requiring further investigation.
Understanding Ovarian Ultrasound
An ultrasound uses high-frequency sound waves to create images of internal organs, including the ovaries. A transducer sends these sound waves through the skin and tissues; when they bounce off organs, the transducer picks up the echoes. A computer then converts these reflected sound waves into a picture displayed on a monitor.
For ovarian imaging, two main methods are employed. A transabdominal ultrasound involves moving the transducer across the lower abdomen, with gel applied to enhance sound wave transmission. A transvaginal ultrasound uses a thin transducer inserted into the vagina, often covered with a protective sheath and lubricant. Both methods allow healthcare providers to visualize the size, shape, and internal structure of the ovaries, and surrounding pelvic organs like the uterus and fallopian tubes.
What Normal Ovaries Look Like
Healthy ovaries on an ultrasound display a consistent appearance. In premenopausal women, ovaries measure approximately 3.5 cm in length, 2.5 cm in height, and 1.5 cm in width. Postmenopausal ovaries are smaller, averaging 2.0 cm by 1.5 cm by 1.0 cm, and are often more difficult to visualize due to the absence of follicles.
Normal ovaries have smooth, distinct outlines. They may contain physiological structures that vary with the menstrual cycle, such as follicles, which appear as small, sonolucent (dark, fluid-filled) rounded sacs that house eggs. One dominant follicle may grow to about 2.5 cm before ovulation. After ovulation, the ruptured follicle transforms into a corpus luteum, a temporary structure ranging from 2-5 cm in diameter, appearing as a thick-walled cyst with characteristic peripheral blood flow. These findings are normal and do not indicate disease.
Identifying Suspicious Features
When an ultrasound reveals features deviating from normal, it raises suspicion for ovarian cancer or other concerning conditions. The presence of solid components within a cyst is an indicator, as simple fluid-filled cysts are less likely to be malignant. Cysts with internal debris, irregular or thick septations (internal divisions), or an irregular ovarian outline warrant further investigation.
Abnormal blood flow patterns, assessed using Doppler ultrasound, are another suspicious feature. Malignant lesions exhibit increased blood supply and a low-resistive pattern, indicating greater blood flow. The presence of ascites, fluid accumulation in the abdomen, is also a sign of advanced ovarian cancer. These characteristics prompt medical professionals to consider additional diagnostic steps.
What Happens After an Ovarian Ultrasound
An ovarian ultrasound serves as an initial imaging and screening tool, but it does not provide a definitive diagnosis of ovarian cancer. Doctors interpret ultrasound findings using standardized reporting systems like the Ovarian-Adnexal Reporting and Data System (O-RADS). O-RADS classifies ovarian lesions into risk categories, guiding subsequent management. For instance, O-RADS 1 indicates a normal ovary or physiological cyst, while higher categories indicate increasing suspicion of malignancy.
If suspicious findings are identified, further evaluation is recommended. This may include additional imaging tests, such as magnetic resonance imaging (MRI) or computed tomography (CT) scans, which offer more detailed views of pelvic organs and assess for spread. Blood tests, like CA-125, are also performed, though CA-125 levels may be elevated by benign conditions and are not definitive for cancer. Ultimately, a biopsy, often during surgery, is the only definitive way to diagnose ovarian cancer by examining cells under a microscope.