PURPOSE: To correlate the enhancement pattern of hepatocellular carcinoma during the arterial phase of spiral CT with vascularity on angiography. MATERIALS AND METHODS: Forty-Two patients with hepatocellular carcinoma underwent spiral CT and angioigraphy. spiral CT was performed with a section thickness of 10mm and a table speedof 10 or 13 mm/sec. 120mL of contrast medium was injected at 3 mL/sec. Spiral CT scans during the arterial phase were obtained 35 seconds after the injection of contrast medium. CT findings of 78 lesions less than 4cm indiameter were correlated with angiographic findings. RESULTS: The attenuation of lesions was high(n=69),iso(n=5), and low(n=4) compared with liver parenchyma during the arterial phase of spiral CT. in lesions with high-, iso-, and low-attenuation during the arterial phase of spiral CT, hypervascularity on angiograms was foundin 63 of 69(91.3%), three of five(60%), and three of four lesions(75%), respectively. Six lesions with high-attenuation on the arterial phase of spiral CT were not seen on angiography. Two iso-attenuated and onelow-attenuated lesion were hypovascular on angiograms. CONCLUSION: The results of this study suggest that with some exceptions there was good correlation between the arterial phase of spiral CT and angiography.