Small nodule detection in cirrhotic livers: Evaluation with US, spiral CT,and MRI and correlation with pathologic examination of explanted liver

Purpose: The purpose of this work was to evaluate the detection and charact erization of nodules greater than or equal to8 tnm and small hepatocellular carcinomas (HCCs) in liver cirrhosis. Method: Pathologic examination and results of US, helical CT, and dynamic M RI with gadolinium were compared after orthotopic liver transplantation (OL T) of 43 cirrhotic patients. Nodules were classified as macroregenerative n odules (MRNs), borderline nodules IBNs), and HCC. Results: Pathologic examination classified 69 nodules: 50 MRNs, 6 BNs, and 13 HCCs, Sensitivities of MRN, BN, and HCC detection were, respectively, fo r US imaging 2% (1/50), 33.3% (2/6), and 46.2% (6/13); for helical CT 2% (1 /50), 50% (3/6), and 53.8% (7/13); and for MRI 42% (21/50), 50% (3/6), and 76.9% (10/13), MRI detected 21 MRNs. They presented on T1/T2-weighted image s as hyperintense/hypointense (n = 8), hyperintense/isointense (n = 7), hyp ointense/hypointense (n = 4), hypointense/isointense (n = 1), and hypointen se depicted only on echo planar imaging(n = 1). The three detected BNs were hyperintense/hypointense nodules. The IO de tee ted HCCs appeared hyperint ense/isointense (n = 7), hyperintense/hypointense (n = 2), and hypointense/ isointense (n = I). None of the MRNs but eight HCCs and one BN were enhance d after gadolinium injection. Conclusion: Contrast-enhanced MRI is the most sensitive technique for detec ting liver nodules. No MR signal intensity pattern characteristic of small HCCs enables differentiation from benign nodules, however. Gadolinium enhan cement is the most sensitive and specific characteristic of HCC.