Focal nodular hyperplasia of the liver: MRI and pathologic correlation

Objective:To evaluate the MR imaging features and the pathologic basis of focal nodular hyperplasia(FNH) of the liver.Methods:The MR imaging features of 9 FNH lesions confirmed by pathology were reviewed retrospectively and correlated with pathologic findings.Results:On unenhanced T_1WI,5 FNH lesions demonstrated isointensity,4 lesions were slightly hypointense;on T_2WI,3 lesions were isointense,6 lesions were slightly hyperintense.The scars were shown in 7 lesions.In the arterial phase of dynamic contrast-enhanced MRI,9 FNHs were markedlyhyperintense,and isointense or slightly hyperintense in the portal and delayed phase.The scars of 7 lesions were enhancd in delayed phase.FNH is solid mass with vast blood supply,its inside structure is homogerneous,hemorrhage and necrosis are seldom.Typical stellate scars can be found by microscopic examination.Conclusion:The combination of unenhanced and dynamic contrast-enhanced MRI is capable of showing the typical images of FNH and reflecting the pathologic characteristics.It increases the sensitivity in diagnosing FNH of liver.