Hepatocellular carcinoma: The role of helical biphasic contrast-enhanced CT versus CT during arterial portography

PURPOSE: To assess the role of helical biphasic computed tomography (CT) versus CT during arterial portography (CTAP) in the detection of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Helical biphasic CT and CTAP examinations were performed in 33 patients with biopsy-proved HCC. Three blinded radiologists retrospectively evaluated portal venous phase images, portal venous phase plus hepatic arterial phase images (helical biphasic CT), and CTAP plus portal venous phase images at separate sittings. In 23 patients with pathologic proof of total tumor burden, the readers conducted a consensus matched-pair reading to determine the sensitivity of each method. RESULTS: In the 23 patients with a proved tumor burden of 100 HCC lesions, the observers detected 74 tumors on portal venous phase images, 82 tumors on hepatic arterial phase images, 87 tumors on CTAP images, 87 tumors on helical biphasic CT images, and 96 tumors on portal venous phase plus CTAP images. Hepatic arterial phase images and CTAP images, respectively, depicted 13 and 23 tumors not seen on portal venous phase images in eight (35%) and 13 (56%) of 23 patients. Ten tumors were seen on portal venous phase images but not on CTAP images owing to the presence of central tumors or segmental portal venous thrombi that obstructed the flow of contrast material to more peripheral portions of the liver. CONCLUSION: The addition of hepatic arterial phase imaging to portal venous phase imaging (helical biphasic CT) provided an incrementally increased yield in HCC tumor detection. Helical biphasic CT should be used as the initial screening examination in patients with suspected or known HCC.