Superiority of CT arterioportal angiography to contrast-enhanced CT and MRI in the diagnosis of hepatocellular carcinoma in nodules smaller than 2 cm

To evaluate the effectiveness of computed tomography (CT) arterioportal angiography in the diagnosis of hepatocellular carcinoma (HCC) in nodules smaller than 2 cm, we compared the findings of CT during arteriography (CTA) and CT during arterial portography (CTAP) with those of enhanced CT and enhanced magnetic resonance imaging (MRI). Sixty-eight nodules smaller than 2 cm in 53 patients with liver cirrhosis were classified into three groups of CTA and CTAP: (group 1) hyperattenuation on CTA, and hypoattenuation on CTAP (56 nodules, 41 patients); (group 2) hypoattenuation on CTA, and hypoattenuation on CTAP (10 nodules, 10 patients); (group 3) hypoattenuation on CTA, and hyperattenuation on CTAP (2 nodules, 2 patients). Histologically, 96% (54/56), 80% (8/10), and 100% (2/2) of the nodules in groups 1, 2 and 3, respectively, were diagnosed as HCC. In group 1, enhanced CT or enhanced MRI confirmed hypervascularity in only 77% (30/39) and venous washout in 21% (8/39). In groups 2 and 3, enhanced CT or enhanced MRI on 7 and 2 nodules, respectively, revealed no hypervascularity (0%). The results suggested that CT arterioportal angiography is superior to enhanced CT and MRI in nodules smaller than 2 cm for diagnosing HCC (p < 0.01 group 1, p < 0.01 group 2).