Eight patients with histologically or clinically diagnosed hepatocellular carcinoma and a total of 23 nodules were studied. SE 2000/20 (PDW-SE), SE-2000/80 (T2W-SE), SE 500/20 (T1W-SE), GRE 167/13/70 degrees (T1W-GE), and GRE 167/13/15 degrees (T2*W-GE) were used. Using each pulse sequence the pre-and post-contrast detection rates of the 23 nodules visualized by CT arterial portography (CTAP) were compared. With plain MRI, the detection rates were PDW-SE: 48%, T2W-SE: 74%, T1W-SE: 52%, T1W-GE 48% and T2*W-GE: 48%. After the administration of contrast medium all pulses sequences showed enhanced detection rates: 100%, 83%, 87%, 91%, and 96% respectively. Superparamagnetic iron oxide particle enhanced MRI showed a high detection rate comparable to CTAP, suggesting that this agent can make a major contribution to the diagnosis of HCC, particularly the detection of small HCC.