The biggest advantage of hepatic arteriography and iodine oil CT after 4 weeks is that they can show some tiny lesions (diameter around 0.3-0.5 cm) that cannot be detected by ultrasound, CT and MRI. If the tumor is less than 1 cm in diameter, it is usually difficult to be detected by ultrasound, CT and MRI, but it can be detected by hepatic arteriography.