Gadoxetic Acid-Enhanced MRI in Differentiating Focal Nodular Hyperplasia from Hepatocellular Adenoma in Children.

Objective: To investigate the diagnostic performance of Gd-EOB-enhanced magnetic resonance imaging (MRI) for distinguishing focal nodular hyperplasia (FNH) from hepatocellular adenoma (HCA) in children.

Methods: Twenty-two patients (6 with HCA and 16 with FNH) were retrospectively included in this study. After qualitative analyses of MRI, quantitative analyses were performed by calculating the relative signal intensity ratios (SIR) between lesion and liver parenchyma both on precontrast and hepatobiliary phase images. Two equations, SIRpost-pre and liver-to-lesion contrast enhancement ratio (LLCER), using both SIRs of precontrast and hepatobiliary phase (HBP) imaging together were also calculated.

Results: The most distinguishing non-contrast-enhanced MRI feature of HCA was intralesional fat since all HCA contained fat but none of FNHs. All FNHs were iso- or hyperintense relative to the adjacent liver on HBP images, but all HCAs except one were hypointense. The mean SIRpost-pre and LLCER of FNH were significantly higher than that of HCA (p < 0,001). SIRpost-pre and LLCER provided sensitivity and specificity values of 100%.

Conclusion: Although intralesional fat is a strong discriminative feature for distinguishing between HCA and FNH, qualitative properties of these lesions may not be enough for confident diagnosis. Gd-EOB uptake in the HBP provides high diagnostic accuracy, but overlap can be seen. SIRpost-pre and LLCER overcome the difficulties and have the best sensitivity and specificity.

Advances in knowledge: Although there are many similar studies in adult group, this is one of the rare studies that will contribute to the literature in the pediatric group.