Focal Nodular Hyperplasia of the Liver:Comparative Study between CT,MRI and Pathology

Objective:To evaluate the CT and MRI findings of hepatic focal nodular hyperplasia (FNH) correlating with pathologic basis.Methods:The CT and MRI findings of 20 patients pathologically confirmed FNH in 18 patients were retrospectively studied and compared with pathological features.Twelve patients were examined by CT,10 patients by MRI,and 4 patients had both CT and MRI examinations.Results:The size of lesions ranged from 1.8~13.5cm.CT found 11 lesions.On precontrast CT,the lesions showed heterogeneous or homogeneous hypo-density.On postcontrast CT,the lesions showed intense and homogeneous enhancement during arterial phase,except for 5 lesions with the central scar.Tor-tuous and dilated arteries were erected around 6 lesions.During portal vein phase,the lesions showed moderate hyper-density.During delayed phase,6 lesions remained mild hyper-density or isodensity and 5 lesions showed hypodensity.5 lesions with central scars demonstrated delayed enhancement.On MR imaging,12 lesions showed slightly long or iso-T1 and T2 signal intensity,demonstrating intense arterial enhancement and moderate portal and delay enhancement on Gd-DTPA contrast studies.Central scar sign 7 lesions showed delayed enhancement.Conclusion:CT and MRI play important roles in the demonstration of blood supply and pathological features of FNH.Dynamic contrast enhancement has a great value in the diagnosis and differential diagnosis of FNH.