Non-invasive diagnosis of hepatocellular carcinoma ⩽2cm in cirrhosis. Diagnostic accuracy assessing fat, capsule and signal intensity at dynamic MRI

To prospectively assess the diagnostic accuracy of the incorporation of additional magnetic resonance imaging (MRI) parameters in those based on contrast enhancement pattern for the diagnosis of solitary nodules between 5 and 20mm, detected during surveillance in patients with cirrhosis.Between November 2003 and January 2010, we prospectively included 159 cirrhotic patients with a newly detected solitary nodule between 5 and 20mm in diameter by screening ultrasonography (US). Hepatic MRI and fine-needle biopsy were performed in all patients.Final diagnoses were hepatocellular carcinoma (HCC) (n=103), other malignant lesions (intrahepatic cholangiocarcinoma/metastases) (n=4), and benign lesions (n=52). The specific enhancement pattern (arterial enhancement followed by washout) yielded a sensitivity and specificity of 58.3% and 96.4%, respectively. Peritumoral capsule was present in 43 HCC and in 2 non-HCC lesions. Intralesional fat was detected in 24 nodules; 5 nodules were non-HCC. Finally, the presence of both capsule and fat was observed in 10 cases, all of them HCC (100% specificity), but all of them also displayed the specific enhancement pattern, thus adding no sensitivity or specificity.Conclusive non-invasive diagnosis of HCC in cirrhosis should be based only on the contrast enhancement pattern, while other characteristics at MRI do not increase the diagnostic accuracy.