Reliable diagnosis of liver focal nodular hyperplasia by a combination of T2 weighted signal and three diffusion magnetic resonance metrics of diffusion-derived 'vessel density', slow diffusion coefficient, and apparent diffusion coefficient: a validation study of two centers' data.

Background: Four Methods: Liver mass DWI patient data were prospectively collected in two hospitals [The Second Hospital of Nanjing and (center 1) and The Fifth Affiliated Hospital of Anhui Medical University (center 2)], totaling 12 cases of FNH and 58 cases of liver malignant tumors [MTs; hepatocellular carcinoma (HCC) n=39, intrahepatic cholangiocarcinoma (ICC) n=10, and metastasis (Met) n=9]. DWI was acquired with free-breathing, long time of repetition (TR), and time of echo (TE) of 82 or 80 ms. DDVD was calculated with Results: Seventy-five percent (9/12) of the FNH had LiverMss ≥4.0, and the remaining three FNH all had LiverMss of 3.0. Two of the FNH lesions scored 3.0 had only one signal sign being untypical of FNH, and one FNH lesion scored 3.0 had very heterogenous atypical signals. Two HCC cases with apparent intralesional hemorrhage were excluded from SQ scoring. Six MT cases had LiverMss 'subtraction approach', with four cases scored '-3', one case scored '-2.5', and one case scored '-2.0', respectively; thus, their LiverMss would be at least ≤1.5 (n=4), ≤2.0 (n=1), ≤2.5 (n=1), respectively. Fifty MT cases had LiverMss assessment. Six out of seven MT cases scored ≥2.5 had liver cirrhosis as evident on magnetic resonance imaging (MRI), and another case had embolization treatment. The remaining MT (43/50) all had LiverMss ≤2.0. Conclusions: LiverMss ≥3.0 suggests the possibility of a liver mass being FNH, and LiverMss ≥4.0 can strongly favor the diagnosis of FNH.