HYPERVASCULAR LIVER METASTASES - DO UNENHANCED AND HEPATIC ARTERIAL PHASE CT IMAGES AFFECT TUMOR-DETECTION

PURPOSE: To evaluate the relative roles of unenhanced and hepatic arte rial phase (HAP) computed tomographic (CT) imaging in the detection of hypervascular liver metastases. MATERIALS AND METHODS: Eighty-four pa tients with biopsy-proved liver metastases from hypervascular primary tumors other than hepatocellular carcinoma underwent unenhanced and HA P and portal venous phase (PVP) helical CT studies. Three blinded radi ologists evaluated each series of images separately for the number, si ze, and enhancement characteristics of lesions. Sixty-nine patients ha d follow-up imaging proof of tumor burden. RESULTS: The three readers detected 381-402 lesions on the PVP images and 397-416 lesions on the unenhanced images. Unenhanced images allowed detection of 72%-80% of t he lesions seen on PVP images. They detected 94-137 additional lesions on unenhanced but not PVP images. On the HAP images, 375-395 lesions were identified. HAP images allowed detection of 81%-90% of the lesion s seen on PVP images. Forty-five to 78 additional lesions were detecte d on HAP but not on PVP images. In the 69-patient subset, maximal dete ction of tumor foci occurred in 94% of patients with unenhanced plus P VP images and in 78% with HAP plus PVP images. Unenhanced plus PVP ima ges allowed detection of 96% of the 322 tumors in the subset populatio n. CONCLUSION: Unenhanced plus PVP CT images allow detection of statis tically significantly more hypervascular liver metastases than do HAP plus PVP images or imaging only in the PVP.