Intrahepatic metastatic nodules of hepatocellular carcinoma detected at Lipiodol-CT: imaging-pathologic correlation

Background: The purpose of this study was to determine whether tiny (<2 cm) areas of iodized-oil retention diagnosed as intrahepatic metastatic nodules of hepatocellular carcinoma (HCC) at computed tomography (CT) following intraarterial injection of Lipiodol (Lipiodol-CT) correlate with truly cancerous foci on the corresponding sectioned pathologic specimens. Methods: Thirty-two consecutive patients with biopsy-proven HCC (26 men and six women, aged 41–72 years) underwent prospective evaluation with Lipiodol-CT before undergoing surgery (hepatic resection, 30 patients; liver transplantation, two patients). Imaging findings were correlated with intraoperative and pathologic findings. Results: Twenty-one areas of retained Lipiodol (0.5–1.6 cm in diameter, mean ± SD: 0.9 ± 0.3 cm) had features consistent with intrahepatic metastatic nodules of HCC on Lipiodol-CT scans. Nineteen of the 21 areas correlated with tumor deposits at pathologic examination of the surgical specimens, whereas two of 21 were due to abnormal retention of iodized oil within noncancerous liver parenchyma. The positive predictive value of findings at Lipiodol-CT for the diagnosis of intrahepatic metastatic nodule of HCC was 90.5%. Conclusions: Findings at Lipiodol-CT enable a reliable diagnosis of intrahepatic metastatic nodules of HCC.