With the rapid progress of various imaging methods, including ultrasonography (US), computed tomography. (CT), digital subtraction angiography (DSA) and magnetic resonance imaging (MRI), it has become possible to detect small liver cancer less than 2 cm in diameter, and the prognosis of hepatocellular carcinomas is now improving rapidly. However, the accurate detection of smaller lesions about 1 cm in diameter and their differential diagnosis are difficult by conventional imaging methods such as US, CT and arteriography. For this purpose, we stressed the effectiveness of the combined use of CT and arteriography (the so-called CT arteriography), CT during arterial portography or Lipiodol CT. The promising future of MRI in this field is also discussed.