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 TZ-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, greater than or equal to 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=1); 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.