We evaluated diagnostically differential radiological findings between focal nodular hyperplasia (FNH)-like lesions and hepatocellular carcinoma (HCC). We studied pathologically confirmed FNH-like lesions in 13 alcoholic-cirrhosis patients who were negative for hepatitis-B surface antigen and hepatitis-C virus antibody and underwent dynamic computed tomography (CT) and magnetic resonance imaging (MRI), including superparamagnetic iron oxide (SPIO) and/or gadoxetic acid-enhanced MRI. Seven patients underwent angiography-assisted CT. Evaluated lesion features included arterial enhancement pattern, washout appearance (low density compared to surrounding liver parenchyma), signal intensity on T1-weighted image (T1WI) and T2-weighted image (T2WI), central scar presence, chemical shift on in- and out-of-phase images, and uptake pattern on gadoxetic acid-enhanced MRI hepatobiliary phase and on SPIO-enhanced MRI. Eleven patients had multiple small lesions (<1.5 cm). Radiological features of FNH-like lesions included hypervascularity despite small lesion, lack of “corona-like” enhancement in the late phase on CT during hepatic angiography (CTHA), high-intensity on T1WI, slightly high- or iso-intensity on T2WI, no signal decrease in out-of-phase images, and complete SPIO uptake or incomplete/partial uptake of gadoxetic acid. Pathologically, like HCC, FNH-like lesions showed many unpaired arteries and sinusoidal capillarization. In summary, FNH-like lesions have unique radiological findings useful for differential diagnosis. Specifically, SPIO- and/or gadoxetic acid-enhanced MRI and CTHA features might facilitate differential diagnosis of FNH-like lesions and HCC.

18F-fluorodeoxyglucose positron emission tomography and computed tomography (18F-FDG PET-CT) is increasingly used in the diagnosis, prognosis, staging, and treatment monitoring of many tumor types. However, only a small number of studies have reported the use of 18F-FDG PET-CT in intrahepatic cholangiocarcinoma (ICC). This study aimed to examine the accuracy of tumor staging in ICC by using 18F-FDG PET-CT. Between January 2009 and December 2020, patients with suspected ICC were retrospectively enrolled in the study and underwent imaging. The sensitivity and specificity of 18F-FDG PET-CT, CT, and magnetic resonance imaging (MRI) in detecting tumors, satellite focus, vascular invasion, and lymph node metastases were analyzed. The efficacy of 18F-FDG PET-CT for tumor staging was evaluated. Of the 110 patients who were enrolled in the study, 52 underwent surgical treatment and 45 were histologically diagnosed with ICC. When compared with CT or MRI, 18F-FDG PET-CT had similar sensitivity and specificity values for diagnosing satellite focus and vascular and bile duct invasion; however, PET-CT showed higher accuracy in diagnosing regional lymph node metastases. The accuracy of tumor staging by 18F-FDG PET-CT was higher than that by CT/MRI. Thus, 18FDG PET-CT may support tumor staging in ICC.