Dysplastic nodules and hepatocellular carcinoma: Thin-section MR imaging of explanted cirrhotic livers with pathologic correlation

PURPOSE: To evaluate detection and characterization of hepatocellular nodules in fresh whole explanted cirrhotic livers at thin-section magnetic resonance (MR) imaging. MATERIALS AND METHODS: T1-weighted spin-echo and T2- weighted fast spin-echo MR imaging (5-mm-thick sections) were performed in a head coil at 1.5 T in the whole cirrhotic livers of 28 consecutive patients within 4 hours of explantation. MR imaging findings were correlated with findings at pathologic examination, and new international terminology was used to classify the hepatocellular nodules. RESULTS: At pathologic examination, 42 suspect (other than regenerative) nodules were identified in 11 patients. MR imaging depicted 41 of 42 (98%) of these nodules (five of five hepatocellular carcinomas [HCCs {diameter, ≤2 cm}], 10 of 10 small HCCs [diameter, < 2 cm], two of two dysplastic nodules with subfoci of HCC, three of three high grade dysplastic nodules, and 21 of 22 low-grade dysplastic nodules. Lesions demonstrated the following combinations of signal intensity characteristics on thin-section T1- and T2-weighted images, respectively: HCC, hyperintense, hypointense (n 3); hyperintense, hyperintense (n = 11; hypointense, isointense (n = 1). Small HCC, hyperintense, hypointense (n = 7); hypointense, hyperintense (n = 2); hyperintense, hyperintense (n = 1). Both dysplastic nodules with subfoci of HCC, hyperintense, hypointense. All seven nonsiderotic low-grade dysplastic nodules, hyperintense, hypointense. All 14 siderotic low-grade dysplastic nodules, hypointense, hypointense. All three high-grade dysplastic nodules, hyperintense, hypointense. CONCLUSION: The variable signal intensity characteristics of HCCs made reliable diagnosis impossible, but the thin section unenhanced in vitro MR images were sensitive for detection of HCCs and dysplastic nodules in cirrhotic livers.