Dynamic CT for detecting small hepatocellular carcinoma: usefulness of delayed phase imaging

Area of Science:

• Radiology
• Hepatology
• Oncology

Background:

• Hepatocellular carcinoma (HCC) is a primary liver malignancy often diagnosed in patients with underlying liver cirrhosis.
• Early detection of small HCCs (< or = 2 cm) is crucial for effective treatment and improved patient outcomes.
• Standard dynamic CT protocols may have limitations in visualizing small HCCs.

Purpose of the Study:

• To evaluate the diagnostic utility of delayed phase imaging in conjunction with arterial and portal venous phases for detecting small HCCs.
• To compare the performance of different combinations of dynamic CT phases in identifying small HCCs in cirrhotic livers.

Main Methods:

• Retrospective analysis of triphasic dynamic CT scans (arterial, portal venous, delayed phases) in 33 patients with 48 pathologically confirmed HCCs and 65 controls.
• Independent review of images by three blinded observers assessing tumor attenuation.
• Receiver operating characteristic (ROC) curve analysis to determine diagnostic performance of combined imaging phases.

Main Results:

• Delayed phase imaging demonstrated hypoattenuation in 43 out of 48 small HCCs.
• The combination of all three phases (arterial, portal venous, delayed) yielded the highest diagnostic performance (A(Z) = 0.940).
• Sensitivity increased with the inclusion of delayed phase imaging, reaching 93.8% for all three phases combined.

Conclusions:

• Delayed phase imaging is a valuable tool for enhancing the detection of small HCCs in patients with liver cirrhosis.
• Incorporating delayed phase imaging into routine dynamic CT protocols can improve the diagnostic yield for small HCCs.