Can an abdominal computed tomography (CT) scan with contrast detect ascites in patients with ovarian cancer?

CT Scan Detection of Ascites in Ovarian Cancer

Yes, an abdominal CT scan with contrast will reliably detect ascites in patients with ovarian cancer, as CT demonstrates very good to excellent sensitivity for identifying peritoneal fluid accumulation. 1

Diagnostic Performance for Ascites Detection

Contrast-enhanced CT of the abdomen and pelvis is the imaging modality of choice for staging ovarian cancer and demonstrates excellent capability for detecting ascites. 1 The American College of Radiology specifically identifies CT as highly effective for detecting ascites in the context of ovarian cancer evaluation. 1

Key Performance Characteristics

• CT has very good sensitivity for detecting ascites in ovarian cancer patients, making it a reliable tool for identifying peritoneal fluid accumulation 1
• Contrast-enhanced CT can identify ascites along with other features suggestive of malignancy including ovarian masses, solid components, and lymphadenopathy 1
• In one study evaluating degenerating fibroids (which shares similar imaging principles), ascites detection by CT demonstrated 100% sensitivity 1

Clinical Context and Ascites in Ovarian Cancer

Prevalence and Significance

• Malignant ascites occurs most frequently in high-grade serous papillary ovarian cancer, with 91.8% of these patients presenting with ascites at initial diagnosis 2
• Ascites is a common presenting feature in advanced ovarian cancer, often leading to symptoms of increased abdominal girth, bloating, nausea, and early satiety 1
• The presence of ascites is highly suggestive of advanced disease and is incorporated into FIGO staging criteria 1

Histologic Variation

• Low-grade serous papillary ovarian cancer shows significantly lower rates of ascites (17.7%) compared to high-grade disease (91.8%), representing a statistically significant difference (P < 0.00001) 2
• Other histologic subtypes show variable rates: mucinous carcinomas (50%), clear cell carcinomas (16.7%), and endometrioid carcinomas (0%) 2

Comprehensive Staging Capabilities

Beyond ascites detection, contrast-enhanced CT with oral contrast of the abdomen and pelvis serves as the primary imaging modality for initial staging of ovarian cancer. 1 This examination should include the chest when indicated for complete staging. 1

Additional CT Findings in Ovarian Cancer

CT effectively identifies:

• Tumor deposits in the mesentery, gastrosplenic ligament, omentum, porta hepatis, liver, diaphragm, and lung parenchyma 1
• Lymphadenopathy throughout the abdomen and pelvis 1
• Peritoneal implants and disease distribution for surgical planning 3

Important Limitations

• Small peritoneal or mesenteric implants (<5 mm) may be difficult to detect on CT 1
• Non-contrast CT offers limited ability to identify small peritoneal implants or lymphadenopathy among bowel loops 1
• Intravenous contrast is preferable for detection and characterization of tumor deposits, making contrast-enhanced studies superior to non-contrast examinations 1

Clinical Pitfalls and Considerations

• While CT excels at detecting moderate to large volume ascites, microscopic peritoneal disease may be present even with negative imaging findings 4
• A normal CT scan cannot completely exclude ovarian cancer, particularly in cases of microscopic or very small volume disease 4
• The presence of ascites on CT in the appropriate clinical context (elevated CA-125, pelvic mass) strongly suggests malignancy and warrants further evaluation 1