MR features of small hepatocellular carcinoma in normal, fibrotic, and cirrhotic livers: a comparative study.

PURPOSE: The objective of this study is to compare MR imaging features of small hepatocellular carcinoma (HCC) (≤ 2 cm) in normal, fibrotic, and cirrhotic liver.

METHODS: A total of 215 patients with 235 pathologically proven sHCC were retrospectively analyzed. Patients were classified into three groups according to the patients' liver condition: patients with normal liver (F0, group 1), fibrosis without cirrhosis (F1-3, group 2), and cirrhosis (F4, group 3). The morphological and MR signal features on T1, T2-weighted, dynamic enhanced, and diffusion-weighted imaging were evaluated and compared.

RESULTS: There were 10, 38, and 167 patients in group 1, 2, and 3, respectively. Patients with normal liver were older than those with fibrosis or cirrhosis (P = 0.0086), and tumors in the normal liver were larger than those in the fibrotic or cirrhotic liver (P = 0.0407). No statistical differences were found among groups in signals on T2-weighted images (P = 0.163), signals on each phase after contrast (P = 0.269, 0.893, and 0.259, respectively), enhancement patterns (P = 0.753), ADC values (P = 0.760), as well as the presence of capsule-like enhancement (P = 0.953), mosaic pattern (P = 0.572), fat content (P = 0.222), iron sparing (P = 1.000), hemorrhage (P = 0.181), and venous invasion (P = 0.175). Both signal-to-noise ratios (SNR) (χ (2) = 2.045, P = 0.132) and lesion-to-liver contrast-to-noise ratios (CNR) (χ (2) = 0.438, P = 0.646) were not different as well. But confusing features of iso/hypointensity on T2-weighted imaging (n = 11, 6.0%) and progressive enhancement pattern (n = 2, 1.1%) were exclusively found in the cirrhosis background, and hypovascular tumors with iso/hypointensity on arterial phase were only seen in the fibrosis (n = 5, 11.9%) and cirrhosis groups (n = 10, 5.5%).

CONCLUSION: MR features of sHCC were similar among patients with normal, fibrotic, and cirrhotic livers.