Early detection significantly improves outcomes for ovarian cancer. Ultrasound is often an initial imaging step to evaluate the ovaries. While it can identify abnormalities, ultrasound does not definitively diagnose ovarian cancer. Instead, it guides further investigation.
How Ultrasound Visualizes Ovarian Concerns
Ultrasound technology uses high-frequency sound waves to generate images of internal body structures, including the ovaries. A small handheld device, called a transducer, emits these sound waves, which then bounce off organs and tissues. The echoes return to the transducer, and a computer translates them into a real-time picture. This allows assessment of the ovaries’ size, shape, and internal structure, as well as any masses.
Two primary types of ultrasound are used for ovarian evaluation: transabdominal and transvaginal. A transabdominal ultrasound involves moving the transducer across the lower abdomen, often with a full bladder to improve visualization. A transvaginal ultrasound involves inserting a thin, lubricated transducer into the vagina, offering a closer and more detailed view of the ovaries. Both methods contribute to a comprehensive assessment of ovarian health.
Key Features Ultrasound Can Identify
When evaluating ovarian masses, radiologists look for specific ultrasound features that suggest malignancy. The size of an ovarian mass is one characteristic; larger masses, particularly those exceeding 10 cm in diameter, are more frequently associated with cancer. The internal composition of the mass is also examined, with the presence of solid components raising suspicion.
Internal divisions, known as septations, are also assessed. Thick or irregular septations, especially those greater than 3 mm, can indicate a higher risk for cancer. Papillary projections, which are small, finger-like growths on the inner or outer surface of an ovarian mass, are another concerning feature. The presence of four or more papillary structures is a sign of potential malignancy.
The presence of fluid in the abdomen, known as ascites, also heightens suspicion for ovarian cancer, especially when seen alongside a pelvic mass. Doppler ultrasound analyzes blood flow patterns within the mass. Malignant tumors often show increased blood flow signals and specific patterns, such as low resistive index (RI) and pulsatility index (PI) values. These characteristics collectively help categorize the risk of an ovarian mass.
Understanding Ultrasound’s Limitations
While ultrasound is a valuable initial imaging tool, it has limitations in definitively diagnosing ovarian cancer. It cannot detect microscopic cancer cells, meaning very early-stage cancers or small metastatic deposits might not be visible. This can lead to false negative results, where cancer is present but not identified by the scan.
Many benign ovarian conditions can mimic the appearance of cancerous ones on an ultrasound, leading to false positive findings. Conditions such as benign cysts, endometriomas, or inflammatory processes can have features that overlap with those of malignant masses. This overlap often necessitates further investigation to differentiate between benign and malignant conditions. The effectiveness of an ultrasound can also depend on the skill and experience of the sonographer.
Next Steps and Confirmatory Tests
If an ultrasound reveals suspicious findings, additional investigations are recommended to establish a definitive diagnosis. Blood tests, such as the CA-125 tumor marker, may be ordered. While CA-125 levels are often elevated in ovarian cancer, they can also be high due to benign conditions like endometriosis or pelvic inflammatory disease, and not all ovarian cancers cause an elevated CA-125. Therefore, CA-125 is not a standalone screening test but rather a supporting piece of information.
Other imaging modalities, such as Computed Tomography (CT) scans or Magnetic Resonance Imaging (MRI), provide more detailed information about the extent of any detected mass and whether it has spread. CT scans assess the abdomen and pelvis for larger tumors and signs of spread, while MRI offers higher resolution for soft tissues and specific lesion characterization.
The only way to confirm ovarian cancer is through a biopsy, which involves removing a tissue sample for microscopic examination by a pathologist. This biopsy is often performed during surgery to remove the mass, or in some cases, a needle biopsy guided by imaging might be used. A multidisciplinary team of specialists then reviews all test results to determine the most appropriate course of action.