Usefulness of digital subtraction imaging with Levovist in the diagnosis of hepatocellular carcinomas

To classify hepatocellular carcinoma (HCC) based on the findings of digital subtraction imaging (DSI) and to compare DSI against other diagnostic imaging modalities to assess its reliability DSI was performed in 68 patients with HCC (72 nodules) and the enhancement patterns of blood flow in the tumor were assessed during the early phase, the portal phase and the late phase. In addition, the findings obtained by DSI were compared with those obtained by helical CT, digital subtraction angiography (DSA), CO2 angiography and CT during arterial portography (CTAP). Of the 72 nodules, blood flow was detected in 64 (88.9%) by early-phase DSI, in 61 (84.7%) by helical CT, in 62 (86.1%) by DSA and in 67 (93.1%) by CO2angiography. Early-phase DSI did not demonstrate hypervascular enhancement in 8 HCC nodules (16.7%). These included 5 nodules in which other diagnostic imaging modalities also failed to identify tumor blood vessels and 3 nodules located in deep regions 87.5 mm or more from the body surface. With regard to these 5 nodules (10.4%) in which tumor vessels were not visualized during the early phase, late-phase DSI demonstrated relatively poor enhancement compared with normal hepatic parenchyma. Such late-phase defects in tumor enhancement were observed in 69 nodules (95.8%). DSI demonstrated characteristic findings of HCC enhancement during the early phase, the portal phase and the late phase, permitting classification of HCC to be performed.