Hepatocellular adenomas: is there additional value in using Gd-EOB-enhanced MRI for subtype differentiation?

Abstract

Purpose To differentiate subtypes of hepatocellular adenoma (HCA) based on enhancement characteristics in gadoxetic acid (Gd-EOB) magnetic resonance imaging (MRI). Materials and methods Forty-eight patients with 79 histopathologically proven HCAs who underwent Gd-EOB-enhanced MRI were enrolled (standard of reference: surgical resection). Two blinded radiologists performed quantitative measurements (lesion-to-liver enhancement) and evaluated qualitative imaging features. Inter-reader variability was tested. Advanced texture analysis was used to evaluate lesion heterogeneity three-dimensionally. Results Overall, there were 19 (24%) hepatocyte nuclear factor (HNF)-1a-mutated (HHCAs), 37 (47%) inflammatory (IHCAs), 5 (6.5%) b-catenin-activated (bHCA), and 18 (22.5%) unclassified (UHCAs) adenomas. In the hepatobiliary phase (HBP), 49.5% (39/79) of all adenomas were rated as hypointense and 50.5% (40/79) as significantly enhancing (defined as > 25% intralesional GD-EOB uptake). 82.5% (33/40) of significantly enhancing adenomas were IHCAs, while only 4% (1/40) were in the HHCA subgroup (p < 0.001). When Gd-EOB uptake behavior was considered in conjunction with established MRI features (binary regression model), the area under the curve (AUC) increased from 0.785 to 0.953 for differentiation of IHCA (atoll sign + hyperintensity), from 0.859 to 0.903 for bHCA (scar + hyperintensity), and from 0.899 to 0.957 for HHCA (steatosis + hypointensity). Three-dimensional region of interest (3D ROI) analysis showed significantly increased voxel heterogeneity for IHCAs (p = 0.038). Conclusion Gd-EOB MRI is of added value for subtype differentiation of HCAs and reliably identifies the typical heterogeneous HBP uptake of IHCAs. Diagnostic accuracy can be improved significantly by the combined analysis of established morphologic MR appearances and intralesional Gd-EOB uptake. Key Points •Gd-EOB-enhanced MRI is of added value for subtype differentiation of HCA. •IHCA and HHCA can be identified reliably based on their typical Gd-EOB uptake patterns, and accuracy increases significantly when additionally taking established MR appearances into account. •The small numbers of bHCAs and UHCAs remain the source of diagnostic uncertainty.

HBP-enhancing hepatocellular adenomas and how to discriminate them from FNH in Gd-EOB MRI

“…In a second step, two readers rated intralesional Gd-EOB uptake in steps of 25%. Both readers in consensus identified 40 HCA lesions with an intralesional Gd-EOB uptake greater than 25%, which were defined as significantly enhancing lesions [25]. In a third step, all histopathologically confirmed FNHs from January 2008 to March 2019 were retrospectively identified (n = 28) from the institutional databases who were examined with a Gd-EOB MRI.…”

“…After intravenous injection of Gd-EOB (0.025 mmol/kg body weight; flow rate of approximately 1-2 mL/s) and a 40 mL saline flush, multiphase T1-w 3D sequences with FS were acquired during breath-holds (arterial phase with a fixed delay of 18 s, portal venous phase with 55 s delay, and transitional phase with 90 s delay). The hepatobiliary phase was acquired with a 3D T1-w FS sequences 20 min after contrast administration [25].…”

“…1). Gd-EOB uptake scores of 0-1 were classified as "non-enhancing" and scores of 2-3 as "significantly enhancing lesion" [25]. Lesions with greater 75% uptake (score 4) were classified as "entirely enhancing lesion" (Fig.…”

“…Occasional, FNHs may show atypical HBP appearances such as partial hypointensity or rim enhancement [5,15,22]. In contrast, a significant portion of HCAs, have recently been shown to appear (partially) hyperintense during the HBP, even mimicking the appearance of FNHs on Gd-EOB MRI [23][24][25]. These findings point to important pitfalls in differentiating FNH and HCA which could lead to unnecessary procedures like biopsies or surgery.…”

Spectrum of liver lesions hyperintense on hepatobiliary phase: an approach by clinical setting

“…Among these observations, those that may show iso-or hyperintensity in the HBP are mainly focal nodular hyperplasia (FNH), areas of fat sparing in steatotic liver, and, seldom, hepatocellular adenomas (HCAs). The likelihood of these observations depends on the patient's on age, gender and risk factors such as oral contraceptives, steroids, history of glycogenosis [10][11][12][13][14][15][16][17]. Cholangiocarcinoma and metastases may show some central enhancement in the HBP phase that is, however, typically lower in comparison with the background parenchyma [18][19][20][21][22][23].…”