High-b-Value Diffusion-weighted MR Imaging of Benign Hepatocellular Lesions: Quantitative and Qualitative Analysis

PURPOSE:To analyze the signal intensity (SI) of benign hepatocellular lesions in high-b-value diffusion-weighted (DW) magnetic resonance (MR) images and to compare the apparent diffusion coefficient (ADC) values of focal nodular hyperplasias (FNHs) with those of hepatocellular adenomas (HCAs). MATERIALS AND METHODS: This retrospective study was approved by institutional review board, with waiver of informed consent. Inclusion criteria were consecutive patients with diagnosed FNH or HCA who underwent MR imaging with a DW sequence of the liver at three b values, 0, 150, and 600 sec/mm2. The final study population included 67 patients (seven men, 60 women) with 90 hepatocellular lesions (54 FNHs, 36 HCAs). The mean ADC was compared between the lesions and the liver. Receiver operating characteristic analysis was performed to evaluate the diagnostic value of ADC for differentiating HCAs and FNHs. RESULTS: The mean ADC value of all FNHs and HCAs was significantly lower than that of the liver (P=.004). An ADC ratio below 15% was observed in 50 of 54 (93%) FNHs and in 29 of 36 (81%) HCAs. The mean ADC value of FNHs was significantly higher than that of HCAs (P