PURPOSE: To evaluate the patterns of pseudo-lesions present on spiral CT hepatic arteriography (CTHA). MATERIALS AND METHODS: One hundred and seventy five patients (161 men and 14 women, aged 15-70 years [mean, 52 years]) who underwent spiral CTHA for the detection of hepatic lesions were retrospectively reviewed.Pseudo-lesion type was determined by comparing hyperattenuating lesions on CTHA with the findings of ultrasonography, conventional or multi-phase CT, Lipiodol CT, angiography, CT arterial portography(CTAP), and follow-up of spiral CTHA. Pseudo-lesions were classified according to site, size and shape. RESULTS: A total of 77 pseudo-lesions were found in 56 of the 175 patients(32.6%), and were classified into the following types :peritumoral(n=18), segment I(n=3), segment IV(n=3), gallbladder fossa (n=13), subsegmental (n=3), subcapsular(n=13), straight line sign (n=10), arterioportal shunt (n=13), and technical error (n=1). Fifteen of 77 pseudo-lesions(19.5%) showed hyperattenuation on CTHA and iso attenuation on CTAP, in contrast to adjacent liverparenchyma. CONCLUSION: In patients with hepatic mass, it is very important to understand the characteristicsite, shape and size of pseudo-lesions for the correct interpretation of CT and subsequent management of thepatient.