Differentiation of focal nodular hyperplasia from hepatocellular adenoma: Role of the quantitative analysis of gadobenate dimeglumine-enhanced hepatobiliary phase MRI

Qualitative and quantitative assessment of gadoxetic acid MRI in distinguishing atypical focal nodular hyperplasia from hepatocellular adenoma subtypes

OBJECTIVE

To assess qualitative and quantitative imaging features, including lesion-to-liver contrast enhancement ratio (LLCER), on gadoxetic acid-enhanced MRI for differentiating atypical focal nodular hyperplasia (aFNH) from hepatocellular adenoma (HCA) subtypes.

MATERIALS AND METHODS

This retrospective study included patients with histopathologically-confirmed aFNH and HCA who underwent gadoxetic acid-enhanced MRI between January 2010 and December 2020. Two radiologists assessed qualitative imaging features and calculated LLCERs for quantitative evaluation of HBP enhancement. Statistical analyses included ROC curves, sensitivity, specificity, and a decision tree.

RESULTS

86 patients (41 ± 11 years; 64 women) had 29 aFNHs and 90 HCAs. HBP iso-/hyperintensity was observed in 72.4% (21/29) of aFNH compared to 28.8% (15/52) of U-HCA, 35% (7/20) of I-HCA, and 0% (0/11) of H-HCA. β-HCA showed 71.4% (5/7) iso-/hyperintensity, overlapping with aFNH (p = 0.17). Homogeneous iso-/hyperintensity and rim-like enhancement were present in 48.3% (14/29) and 20.7% (6/29) of aFNH but absent in β-HCA (p = 0.004). LLCER demonstrated high diagnostic performance, differentiating aFNH from U-HCA, H-HCA, and I-HCA(AUCs 0.91-0.99, sensitivities 82.8-96.6%, specificities 90.0-100%). For β-HCA, LLCER showed overlap with aFNH; AUCs (0.62-0.64) and specificities (57.1%). Among HCAs with HBP iso-/hyperintensity, 74.1% had negative LLCER values, while 25.9% (mostly β-HCA/U-HCA) showed positive values (true enhancement). Combined decision trees selected LLCER as the primary node, with downstream HBP features variably incorporated, except β-HCA, which solely used qualitative features.

CONCLUSION

HBP iso-/hyperintensity and LLCER reliably differentiated aFNH from most HCA subtypes, except β-HCA, validated by decision tree analyses. Homogeneous iso-/hyperintensity or rim-like enhancement was absent in β-HCA, aiding differentiation.

KEY POINTS

Question Variability in hepatobiliary phase (HBP) enhancement among hepatocellular adenoma (HCA) subtypes and atypical FNH (aFNH) poses diagnostic challenges. Findings Despite HBP enhancement overlap in aFNH/β-HCA, "homogeneous" and rim-like enhancement aided aFNH differentiation from HCAs. LLCER separated HCAs lacking true HBP uptake from aFNH. Clinical relevance This study explored challenges in differentiating aFNH from HCA subtypes, especially overlapping β-HCA, highlighting discriminatory qualitative markers and quantitative assessment to distinguish true HBP enhancement, an approach validated by decision tree analysis.

A Multicenter Study on Hepatocellular Adenomas in Korea: Clinicopathological and Imaging Features With an Emphasis on β-Catenin Mutated Subtype

BACKGROUND & AIMS

The clinicopathologic and imaging features of hepatocellular adenomas (HCAs) in Asian population remain unclear. We aimed to analyse clinicopathologic and imaging features of HCAs in Korea and propose an imaging-based method to differentiate β-catenin mutated HCA (βHCA) from other subtypes.

METHODS

This retrospective multicenter study included pathologically confirmed HCAs from three tertiary institutions in Korea between 2010 and 2023. HCA subtypes were determined according to the current World Health Organization classification using immunohistochemical staining. Two abdominal radiologists reviewed computed tomography and magnetic resonance imaging scans. The clinical characteristics and imaging features of HCA subtypes were compared. A scoring system for βHCA was developed and validated using development (January 2010-April 2021) and validation (May 2021-March 2023) cohorts.

RESULTS

121 patients (47 men; mean age, 39.0 years ±13.5) with 138 HCAs were included. HCAs displayed characteristic clinicopathologic features, including a high proportion of male (38.8%) and obese patients (35.5%), with the inflammatory subtype being the most common (38.4%) and a low percentage of patients using oral contraceptive (5.0%). Each HCA subtype demonstrated distinct clinical and imaging features. The scoring system incorporating tumour heterogeneity and iso to high hepatobiliary phase signal intensity on MRI for differentiating βHCA exhibited high performance in both the development (AUC 0.92, 95% CI: 0.87-0.97) and the validation cohort (AUC 0.91, 95% CI: 0.77-1.00).

CONCLUSIONS

This comprehensive analysis of clinicopathologic and imaging features of HCAs in Korea contributes to the characterisation of HCAs across different geographical regions. The imaging-based scoring system effectively differentiates βHCA.

Gadoxetic acid-enhanced MRI in differentiating focal nodular hyperplasia from hepatocellular adenoma in children

OBJECTIVE

To investigate the diagnostic performance of gadoxetic acid (Gd-EOB)-enhanced MRI for distinguishing focal nodular hyperplasia (FNH) from hepatocellular adenoma (HCA) in children.

METHODS

Twenty-two patients (HCA, n = 6; FNH, n = 16) underwent MRI with Gd-EOB were retrospectively included in this study. The diagnosis was established by biopsy in eight patients and by imaging criteria and follow-up in 13 patients. 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 (HBP) images. Two equations, SIRpost-pre and liver-to-lesion contrast enhancement ratio (LLCER), using both SIRs of precontrast and 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 < .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

Gadoxetic acid-enhanced MRI is a valuable tool for differentiation of FNH and HCA in children.

Lesions hyper- to isointense to surrounding liver in the hepatobiliary phase of gadoxetic acid-enhanced MRI

OBJECTIVES

Hyper- or isointensity in the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MRI has high specificity for focal nodular hyperplasia (FNH) but may be present in hepatocellular adenoma and carcinoma (HCA/HCC). This study aimed to identify imaging characteristics differentiating FNH and HCA/HCC.

MATERIALS AND METHODS

This multicenter retrospective cohort study included patients with pathology-proven FNH or HCA/HCC, hyper-/isointense in the HBP of gadoxetic acid-enhanced MRI between 2010 and 2020. Diagnostic performance of imaging characteristics for the differentiation between FNH and HCA/HCC were reported. Univariable analyses, multivariable logistic regression analyses, and classification and regression tree (CART) analyses were conducted. Sensitivity analyses evaluated imaging characteristics of B-catenin-activated HCA.

RESULTS

In total, 124 patients (mean age 40 years, standard deviation 10 years, 108 female) with 128 hyper-/isointense lesions were included. Pathology diagnoses were FNH and HCA/HCC in 64 lesions (50%) and HCA/HCC in 64 lesions (50%). Imaging characteristics observed exclusively in HCA/HCC were raster and atoll fingerprint patterns in the HBP, sinusoidal dilatation on T2-w, hemosiderin, T1-w in-phase hyperintensity, venous washout, and nodule-in-nodule partification in the HBP and T2-w. Multivariable logistic regression and CART additionally found a T2-w scar indicating FNH, less than 50% fat, and a spherical contour indicating HCA/HCC. In our selected cohort, 14/48 (29%) of HCA were B-catenin activated, most (13/14) showed extensive hyper-/isointensity, and some had a T2-w scar (4/14, 29%).

CONCLUSION

If the aforementioned characteristics typical for HCA/HCC are encountered in lesions extensively hyper- to isointense, further investigation may be warranted to exclude B-catenin-activated HCA.

CLINICAL RELEVANCE

Hyper- or isointensity in the HBP of gadoxetic acid-enhanced MRI is specific for FNH, but HCA/HCC can also exhibit this feature. Therefore, we described imaging patterns to differentiate these entities.

KEY POINTS

FNH and HCA/HCC have similar HBP intensities but have different malignant potentials. Six imaging patterns exclusive to HCA/HCC were identified in this lesion population. These features in liver lesions hyper- to isointense in the HBP warrant further evaluation.

Quantitative information from gadobenate dimeglumine-enhanced MRI can predict proliferative subtype of solitary hepatocellular carcinoma: a multicenter retrospective study

OBJECTIVES

To investigate the value of quantitative parameters derived from gadobenate dimeglumine-enhanced magnetic resonance imaging (MRI) for predicting molecular subtype of hepatocellular carcinoma (HCC) and overall survival.

METHODS

This multicenter retrospective study included 218 solitary HCC patients who underwent gadobenate dimeglumine-enhanced MRI. All HCC lesions were resected and pathologically confirmed. The lesion-to-liver contrast enhancement ratio (LLCER) and lesion-to-liver contrast (LLC) were measured in the hepatobiliary phase. Potential risk factors for proliferative HCC were assessed by logistic regression. The ability of LLCER and LLC to predict proliferative HCC was assessed by the receiver operating characteristic (ROC) curve. Prognostic factors were evaluated using the Cox proportional hazards regression model for survival outcomes.

RESULTS

LLCER was an independent predictor of proliferative HCC (odds ratio, 0.015; 95% confidence interval [CI], 0.008-0.022; p < 0.001). The area under the ROC curve was 0.812 (95% CI, 0.748-0.877), higher than that of LLC, alpha-fetoprotein > 100 ng/ml, satellite nodules, and rim arterial phase hyperenhancement (all p ≤ 0.001). HCC patients with LLCER < -4.59% had a significantly higher incidence of proliferative HCC than those with the LLCER ≥ -4.59%. During the follow-up period, LLCER was an independent predictor of overall survival (hazard ratio, 0.070; 95% CI, 0.015-0.324; p = 0.001) in HCC patients.

CONCLUSIONS

Gadobenate dimeglumine-enhanced quantitative parameter in the hepatobiliary phase can predict the proliferative subtype of solitary HCC with a moderately high accuracy.

CLINICAL RELEVANCE STATEMENT

Quantitative information from gadobenate dimeglumine-enhanced MRI can provide crucial information on hepatocellular carcinoma subtypes. It might be valuable to design novel therapeutic strategies, such as targeted therapies or immunotherapy.

KEY POINTS

• The lesion-to-liver contrast enhancement ratio (LLCER) is an independent predictor of proliferative hepatocellular carcinoma (HCC). • The ability of LLCER to predict proliferative HCC outperformed lesion-to-liver contrast, alpha-fetoprotein > 100 ng/ml, satellite nodules, and rim arterial phase hyperenhancement. • HCC patients with LLCER < -4.59% had a significantly higher incidence of proliferative HCC than those with the LLCER ≥ -4.59%.

Hepatocellular Adenomas: Molecular Basis and Multimodality Imaging Update

Hepatocellular adenomas (HCAs) are a family of liver tumors that are associated with variable prognoses. Since the initial description of these tumors, the classification of HCAs has expanded and now includes eight distinct genotypic subtypes based on molecular analysis findings. These genotypic subtypes have unique derangements in their cellular biologic makeup that determine their clinical course and may allow noninvasive identification of certain subtypes. Multiphasic MRI performed with hepatobiliary contrast agents remains the best method to noninvasively detect, characterize, and monitor HCAs. HCAs are generally hypointense during the hepatobiliary phase; the β-catenin-mutated exon 3 subtype and up to a third of inflammatory HCAs are the exception to this characterization. It is important to understand the appearances of HCAs beyond their depictions at MRI, as these tumors are typically identified with other imaging modalities first. The two most feared related complications are bleeding and malignant transformation to hepatocellular carcinoma, although the risk of these complications depends on tumor size, subtype, and clinical factors. Elective surgical resection is recommended for HCAs that are persistently larger than 5 cm, adenomas of any size in men, and all β-catenin-mutated exon 3 HCAs. Thermal ablation and transarterial embolization are potential alternatives to surgical resection. In the acute setting of a ruptured HCA, patients typically undergo transarterial embolization with or without delayed surgical resection. This update on HCAs includes a review of radiologic-pathologic correlations by subtype and imaging modality, related complications, and management recommendations. ^© RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Prediction of early recurrence of hepatocellular carcinoma after resection based on Gd-EOB-DTPA enhanced magnetic resonance imaging: a preliminary study

BACKGROUND

Early recurrence (ER) after radical resection of hepatocellular carcinoma (HCC) affects the prognosis of patients. Gadolinium ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) can improve the detection rate of small HCC. This study innovatively introduces a new quantitative index combined with qualitative index to compare the differences in clinical and imaging characteristics between ER and non-ER groups and evaluate the feasibility of Gd-EOB-DTPA-enhanced MRI in predicting ER.

METHODS

A total of 68 patients with HCC confirmed by operation and pathology in the Shandong Cancer Hospital and Institute were included retrospectively. All participants were examined by Gd-EOB-DTPA-enhanced MRI within 3 weeks before surgery. Regular follow-up was performed every 2 months within 1 year after operation. Among them, 18 cases with new lesions were in ER group, and 50 cases without new lesions were in non-ER group. The clinical and imaging data of the 2 groups were collected, and the differences of clinical data and preoperative MRI signs between the ER group and non-ER group were compared. The predictive factors of ER after HCC were analyzed by multivariate logistic regression.

RESULTS

The quantitative parameter lesion-to-liver contrast enhancement ratio (LLCER) can predict the pathological grade of HCC (P=0.023). The results of univariate analysis between the ER group and non-ER group showed that there were significant differences in pathological grade (P=0.008), lesion morphology (P=0.011), peritumoral low signal intensity in hepatobiliary phase (HBP) (P<0.001), satellite nodules (P<0.001), and LLCER (P<0.001) between the 2 groups. Multivariate logistic regression analysis showed that HBP peritumoral low signal intensity [odds ratio (OR) =7.214, 95% confidence interval (CI): 1.230-42.312, P=0.029], satellite nodules (OR =9.198, 95% CI: 1.402-60.339, P=0.021), and parameter LLCER value (OR =0.906, 95% CI: 0.826-0.995, P=0.039) were independent predictors of ER of HCC after resection.

CONCLUSIONS

Preoperative Gd-EOB-DTPA enhanced MRI has important predictive value for early recurrence after radical resection of hepatocellular carcinoma.

Hepatospecific MR contrast agent uptake on hepatobiliary phase can be used as a biomarker of marked β-catenin activation in hepatocellular adenoma

OBJECTIVES

To assess the value of hepatospecific MR contrast agent uptake on hepatobiliary phase (HBP) images to detect marked activation of the β-catenin pathway in hepatocellular adenomas (HCAs).

METHODS

This multicentric retrospective IRB-approved study included all patients with a pathologically proven HCA who underwent gadobenate dimeglumine-enhanced liver MRI with HBP. Tumor signal intensity on HBP was first assessed visually, and lesions were classified into three distinct groups-hypointense, isointense, or hyperintense-according to the relative signal intensity to liver. Uptake was then quantified using the lesion-to-liver contrast enhancement ratio (LLCER). Finally, the accuracy of HBP analysis in depicting marked β-catenin activation in HCA was evaluated.

RESULTS

A total of 124 HCAs were analyzed including 12 with marked β-catenin activation (HCA B+). Visual analysis classified 94/124 (76%), 12/124 (10%), and 18/124 (14%) HCAs as being hypointense, isointense, and hyperintense on HBP, respectively. Of these, 1/94 (1%), 3/12 (25%), and 8/18 (44%) were HCA B+, respectively (p < 0.001). The LLCER of HCA B+ was higher than that of HCA without marked β-catenin activation in the entire cohort (means 4.9 ± 11.8% vs. - 19.8 ± 11.4%, respectively, p < 0.001). A positive LLCER, i.e., LLCER ≥ 0%, had 75% (95% CI 43-95%) sensitivity and 97% (95% CI 92-99%) specificity, with a LR+ of 28 (95% CI 8.8-89.6) for the diagnosis of HCA B+.

CONCLUSIONS

Hepatospecific contrast uptake on hepatobiliary phase is strongly associated with marked activation of the β-catenin pathway in hepatocellular adenoma, and its use might improve hepatocellular adenoma subtyping on MRI.

KEY POINTS

• Tumor uptake on hepatobiliary phase in both the visual and quantitative analyses had a specificity higher than 90% for the detection of marked β-catenin activation in hepatocellular adenoma. • However, the sensitivity of visual analysis alone is inferior to that of LLCER quantification on HBP due to the high number of HCAs with signal hyperintensity on HBP, especially those developed on underlying liver steatosis.

New insights in the management of Hepatocellular Adenoma

Hepatocellular adenoma (HCA) are benign liver tumours that may be complicated by haemorrhage or malignant transformation to hepatocellular carcinoma. Epidemiological data are fairly outdated, but it is likely to assume that the incidence has increased over the past decades as HCA are more often incidentally found due to the more widespread use of imaging techniques and the increased incidence of obesity. Various molecular subgroups have been described. Each of these molecular subgroups are defined by specific gene mutations and pathway activations. Additionally, they are all related to specific risk factors and show a various biological behaviour. These molecular subgroups may be identified using immunohistochemistry and molecular characterization. Contrast-enhanced MRI is the recommended imaging modality to analyse patients with suspected hepatocellular adenoma allowing to determine the subtype in up to 80%. Surgical resection remains to be the golden standard in treating HCA, although resection is deemed unnecessary in a large number of cases, as studies have shown that the majority of HCA will regress over time without complications such as haemorrhage or malignant transformation occurring. It is preferable to treat patients with suspected HCA in high volume centres with combined expertise of liver surgeons, hepatologists, radiologists and (molecular) pathologists.

Hepatobiliary MR contrast agent uptake as a predictive biomarker of aggressive features on pathology and reduced recurrence-free survival in resectable hepatocellular carcinoma: comparison with dual-tracer 18F-FDG and 18F-FCH PET/CT

OBJECTIVES

To compare the performance of the quantitative analysis of the hepatobiliary phase (HBP) tumor enhancement in gadobenate dimeglumine (Gd-BOPTA)-enhanced MRI and of dual-tracer 18F-FDG and 18F-fluorocholine (FCH) PET/CT for the prediction of tumor aggressiveness and recurrence-free survival (RFS) in resectable hepatocellular carcinoma (HCC).

METHODS

This retrospective, IRB approved study included 32 patients with 35 surgically proven HCCs. All patients underwent Gd-BOPTA-enhanced MRI including delayed HBP images, 18F-FDG PET/CT, and (for 29/32 patients) 18F-FCH PET/CT during the 2 months prior to surgery. For each lesion, the lesion-to-liver contrast enhancement ratio (LLCER) on MRI HBP images and the SUV_max tumor-to-liver ratio (SUV_T/L) for both tracers were calculated. Their predictive value for aggressive pathological features-including the histological grade and microvascular invasion (MVI)-and RFS were analyzed and compared using area under receiver operating characteristic (AUROC) curves and Cox regression models, respectively.

RESULTS

The AUROCs for the identification of aggressive HCCs on pathology with LLCER, 18F-FDG SUV_T/L, and 18F-FCH SUV_T/L were 0.92 (95% CI 0.78, 0.98), 0.89 (95% CI 0.74, 0.97; p = 0.70), and 0.64 (95% CI 0.45, 0.80; p = 0.035). At multivariate Cox regression analysis, LLCER was identified as an independent predictor of RFS (HR (95% CI) = 0.91 (0.84, 0.99), p = 0.022). LLCER - 4.72% or less also accurately predicted moderate-poor differentiation grade (Se = 100%, Sp = 92.9%) and MVI (Se = 93.3%, Sp = 60%) and identified patients with poor RFS after surgical resection (p = 0.030).

CONCLUSIONS

HBP tumor enhancement after Gd-BOPTA injection may help identify aggressive HCC pathological features, and patients with reduced recurrence-free survival after surgical resection.

KEY POINTS

• In patients with resectable HCC, the quantitative analysis of the HBP tumor enhancement in Gd-BOPTA-enhanced MRI (LLCER) accurately identifies moderately-poorly differentiated and/or MVI-positive HCCs. • After surgical resection for HCC, patients with LLCER - 4.72% or less had significantly poorer recurrence-free survival than patients with LLCER superior to - 4.72%. • Gd-BOPTA-enhanced MRI with delayed HBP images may be suggested as part of pre-surgery workup in patients with resectable HCC.

Response to Letter: Intrapatient Comparison of the Hepatobiliary Phase of Gd-BOPTA and Gd-EOB-DTPA in the Differentiation of HCA From FNH

LEVEL OF EVIDENCE

5 TECHNICAL EFFICACY STAGE: 3 J. Magn. Reson. Imaging 2020;52:1281-1282.

Reply to "Intrapatient Comparison of the Hepatobiliary Phase of Gd-BOPTA and Gd-EOB-DTPA in the Differentiation of Hepatocellular Adenoma From Focal Nodular Hyperplasia"

LEVEL OF EVIDENCE

5 TECHNICAL EFFICACY STAGE: 3 CONFLICT OF INTEREST: None.

FINANCIAL SUPPORT

None. J. Magn. Reson. Imaging 2020;52:1279-1280.

Identification of Arterial Hyperenhancement in CT and MRI in Patients with Hepatocellular Carcinoma: Value of Unenhanced Images

Objective

According to the current guidelines, arterial hyperenhancement for diagnosis of hepatocellular carcinoma (HCC) is determined using the arterial phase only. We investigated the optimal definition of arterial hyperenhancement in patients with HCC using computed tomography (CT) and magnetic resonance imaging (MRI).

Materials and Methods

The Institutional Review Board approved this retrospective study. The requirement for informed consent was waived. Between January 2011 and September 2013, 147 consecutive patients with surgically proven HCCs with both pre-operative CT and MRI were included. Identification rates of arterial hyperenhancement on CT and magnetic resonance (MR) images using arterial phase only, dual phase (unenhanced and arterial phases), and also subtraction MR images were assessed qualitatively.

Results

The identification rates for arterial hyperenhancement on CT were significantly different between arterial phase and dual phase (72.8% vs. 90.5%; p < 0.001), whereas the rates were similar on MRI (91.8% vs. 93.9%; p = 0.257). The identification rate of arterial hyperenhancement in MRI increased to 98.6% using subtraction MR images.

Conclusion

Visual comparison of arterial and unenhanced phases could be recommended instead of conventional qualitative arterial phase alone assessment to determine arterial hyperenhancement of HCCs, especially when using CT.

MRI for characterization of benign hepatocellular tumors on hepatobiliary phase: the added value of in-phase imaging and lesion-to-liver visual signal intensity ratio

OBJECTIVES

To evaluate the lesion-to-liver visual signal intensity ratio (SIR) before and at the hepatobiliary phase MRI (HBP-MRI) after gadobenate dimeglumine (Gd-BOPTA) injection, using several T1-weighted images (T1-WI), for the characterization of benign hepatocellular lesions.

METHODS

Patients with histologically proven focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA), who underwent Gd-BOPTA-enhanced HBP-MRI from 2009 to 2017, were retrospectively identified. The lesion-to-liver SIR was visually assessed by two radiologists on HBP (post-HBP analysis) and compared with that of unenhanced sequences (pre/post-HBP analysis) on T1-WI in-phase (T1-IP), out-of-phase (T1-OP), and fat suppression (T1-FS). Lesions were classified as hyper-, iso-, or hypointense on post-HBP, and as decreasing, stable, or increasing SIR on pre/post-HBP analyses. The performance of the different T1-WI sequences for the diagnostic of FNH was evaluated on post-HBP analysis.

RESULTS

Twenty-nine FNHs and 33 HCAs were analyzed. On post-HBP analysis, FNHs appeared hyper-/isointense in 89.7% of all T1-WI. HCAs appeared hypointense in 93.9%, 63.6%, and 69.7% of T1-IP, T1-OP, and T1-FS, respectively. FNHs exhibited an increasing SIR in 55.2-58.6%, a stable SIR in 44.8-58.6%, and a decreasing SIR in 0%, whereas HCAs exhibited a decreasing SIR in 66.7-93.9%, a stable SIR in 6.1-33.3%, and an increasing SIR in 0% (p < 0.0001). The specificity of T1-IP was significantly higher than that of T1-OP (p = 0.015) and T1-FS (p = 0.042).

CONCLUSION

T1-IP is the most reliable sequence due to misleading tumor/liver signal ratio in the case of fatty liver when using T1-FS or T1-OP. The pre/post-HBP lesion-to-liver SIR is accurate to classify benign hepatocellular lesions and contributes to avoid biopsy.

KEY POINTS

•The T1-weighted images in-phase should be systematically included in the HBP-MRI protocol, as it is the most reliable sequence especially in the case of fatty liver. •The comparison between lesion-to-liver signal intensity ratios on unenhanced and at the hepatobiliary phase sequences is useful to classify benign hepatocellular lesions in three categories without misclassification: FNH (increasing signal intensity ratio), HCA (decreasing signal intensity ration), and indeterminate lesions (stable signal intensity ratio).

Differentiating focal nodular hyperplasia from hepatocellular adenoma: Is hepatobiliary phase MRI (HBP-MRI) using linear gadolinium chelates always useful?

PURPOSE

To assess the value of Hepatobiliary phase MRI (HPB-MRI) to differentiate FNH and HCA, and evaluate its impact on diagnostic accuracy, diagnostic confidence, inter-observer variability, and patient clinical management.

METHODS

Forty-nine patients referred for Gd-BOPTA-enhanced MRI were retrospectively included in this IRB-approved study, with a total of 119 lesions-90 FNH and 29 HCA. Two observers separately assessed in 2 distinct randomized reading sessions the performance of MRI with (HBP-MRI) or without (conventional MRI) the use of HBP images. Each lesion was ranked with a 5-point scale (from 1 Typical FNH to 5 Certainly not a FNH). Sensitivity, specificity, overall accuracy, and inter-observer agreement for the differentiation of FNH from HCA were calculated and compared between conventional and HBP-MRI.

RESULTS

Both sensitivity (respective values of 38.9% and 97.8%), overall accuracy (respective values of 53.8% and 98.3%), and inter-observer agreement (respective values of Kappa 0.56 and 0.88) were significantly higher using HBP-MRI than with conventional MRI, with unchanged specificity (100%). The sensitivity of conventional MRI for the diagnosis of FNH was significantly lower in lesions ≤ 3 cm (20% vs. 88%). Overall, HBP could have changed lesion management in 59/119 cases (49.5%), including 53 FNH and 6 HCA with no impact in 60/119 lesions (50.5%) including all 35 lesions classified as scores 1 and 2 for the diagnosis of FNH.

CONCLUSIONS

The clinical impact of HBP-MRI is mostly important for smaller than 3-cm FNH, and more limited in larger FNH lesions as well as for HCA diagnosis for which conventional MRI is already accurate. The use of extracellular contrast agents upfront could limit the required use of linear HBP contrast agents for benign hepatocellular lesion characterization. On HBP, all FNH appeared hypointense compared to adjacent liver while close to 97% of HCA appeared hypointense.

Quantitative correlation between uptake of Gd-BOPTA on hepatobiliary phase and tumor molecular features in patients with benign hepatocellular lesions

PURPOSE

The purpose of our study was to correlate the quantitative analysis of benign hepatocellular tumor uptake on delayed hepatobiliary phase (HBP) imaging with the quantitative level of OATP expression.

METHODS

This single-center retrospective study, which took place between September 2009 and March 2015, included 20 consecutive patients with a proven pathologic and immunohistochemical (IHC) diagnosis of FNH or HCA, including quantification of the OATP expression. The patients underwent Gd-BOPTA-enhancement MRI, including an HBP. The analysis of HBP uptake was performed using the liver-to-lesion contrast enhancement ratio (LLCER). Mean LLCER and OATP expressions were compared between FNH and HCA, and the expression of OATP was correlated with the LLCER value.

RESULTS

Of the 23 benign hepatocellular tumors, 9 (39%) were FNH and 14 (61%) were HCA, including 6 inflammatory, 2 HNF1a inactivated, 3 β-catenin-mutated and 3 unclassified HCAs. On HBP, 100% of the FNH appeared hyper- or isointense, and 79% of the adenomas appeared hypointense. The mean OATP expression of FNH (46.67 ± 26.58%) was significantly higher than that of HCA (22.14 ± 30.74%) (p = 0.0273), and the mean LLCER of FNH (10.66 ± 7.403%) was significantly higher than that of HCA (-13.5 ± 12.25%) (p < 0.0001). The mean LLCER of β-catenin-mutated HCA was significantly higher than that of other HCAs (p = 0.011). Significant correlation was found between the OATP expression and LLCER values (r = 0.661; p = 0.001).

CONCLUSION

In benign hepatocellular tumors, the quantitative analysis of hepatobiliary contrast agent uptake on HBP is correlated with the level of OATP expression and could be used as an imaging biomarker of the molecular background of HCA and FNH.

KEY POINTS

• Gd-BOPTA uptake on HBP correlates with the OATP level in benign hepatocellular tumors • FNH and β-catenin-mutated HCA showed an increased lesion-to-liver contrast enhancement ratio (LLCER) • Increased LLCER may be explained by activation of the Wnt β-catenin pathway.

Molecular classification of hepatocellular adenomas: impact on clinical practice

Hepatocellular adenomas are rare benign liver tumors usually developing in young women using oral contraception. The two main complications are hemorrhage (10–20%) and malignant transformation into hepatocellular carcinoma (<5%). A molecular classification has been recently updated in six major subgroups, linked to risk factors, histology, imaging and clinical features: adenomas inactivated for HNF1A, inflammatory adenomas, β-catenin-activated adenomas mutated in exon 3, β-catenin-activated adenomas mutated in exon 7–8, sonic hedgehog adenomas, and unclassified adenomas. Indeed, β-catenin-mutated adenomas in exon 3 are associated with malignant transformation, and sonic hedgehog adenomas with bleeding. This new nosology of hepatocellular adenomas will help to stratify patients according to risk of complications and will guide therapeutics in the future.

Efficacy comparison of multi-phase CT and hepatotropic contrast-enhanced MRI in the differential diagnosis of focal nodular hyperplasia: a prospective cohort study

Background

Different clinical behaviour influences the importance of differentiating focal nodular hyperplasia (FNH) from other focal liver lesions (FLLs). The aim of this study was to compare the efficacy of contrast-enhanced CT and MRI in the diagnosis of FNH.

Methods

157 patients with equivocal FLLs detected in ultrasonography subsequently underwent multi-phase CT and MRI with the use of hepatotropic contrast agent (Gd-BOPTA) in a 1.5 T scanner. Examinations were evaluated by three independent readers. Diagnostic efficacy of different radiological signs of FNH in both CT and MRI was compared and AFROC analysis was performed.

Results

4 hepatocellular adenomas, 95 hepatocellular carcinomas, 98 hemangiomas, 138 metastases and 45 FNHs were diagnosed. In both CT and MRI the radiological sign of the highest accuracy was the presence of the central scar within FNH (0.93 and 0.96 relatively). The sum of two radiological signs in MRI: homogeneous enhancement in hepatic arterial phase (HAP) and enhancing lesion in hepatobiliary phase (HBP) was characterized with high values of sensitivity (0.89), specificity (0.97), PPV (0.82), NPV (0.98) and accuracy (0.96). After inclusion of clinical data into analysis the best discriminating feature in MRI was the presence of enhancing lesion in HBP in patients without cirrhosis. In this regard, efficacy parameters increased to 1.00, 0.99, 0.94, 1.00 and 0.99 accordingly. The area under the curve in AFROC analysis of MRI performance was significantly larger than of CT (p = 0.0145).

Conclusion

Gd-BOPTA-enhanced MRI is a more effective method in the differential diagnosis of FNH than multi-phase CT.

Electronic supplementary material

The online version of this article (10.1186/s12876-017-0719-1) contains supplementary material, which is available to authorized users.

Molecular classification of hepatocellular adenoma in clinical practice

Hepatocellular adenomas (HCA) are rare benign liver tumors occurring in young women taking contraception. They are associated with rare complications such as bleeding or malignant transformation into hepatocellular carcinoma. A molecular classification has divided HCA in several subgroups linked with risk factors, clinical behaviour, histological features and imaging: HNF1A inactivated HCA, Inflammatory HCA, CTNNB1 mutated HCA in exon 3, CTNNB1 mutated in exon 7 and 8 HCA, sonic hedgehog HCA and unclassified HCA. CTNNB1 mutated HCA in exon 3 and sonic hedgehog HCA have been linked with a high risk of malignant transformation and bleeding respectively. Herein, we review how molecular classification has modified our understanding of the pathophysiology and risk factors of HCA development, analysing its impact on clinical care in the field of diagnosis and therapeutic stratification.

Impact of hepatobiliary phase liver MRI versus Contrast-Enhanced Ultrasound after an inconclusive extracellular gadolinium-based contrast-enhanced MRI for the diagnosis of benign hepatocellular tumors

PURPOSE

To compare the added values of hepatobiliary phase (HBP) MRI and contrast-enhanced ultrasound (CEUS) in addition to inconclusive extracellular gadolinium-based contrast-enhanced MRI (CE-MRI) to characterize benign hepatocellular tumors (BHT).

METHODS

Eighty-three BHT-46 focal nodular hyperplasia (FNH) and 37 hepatocellular adenomas (HCA)-with inconclusive CE-MRI in 54 patients (43 women and 11 men, mean age 42 years old ± 14.8) were retrospectively analyzed. All patients underwent both HBP-MRI and CEUS. Two radiologists independently reviewed 2 sets of images, SET-1: CE-MRI and HBP-MRI; SET-2: CE-MRI and CEUS, and classified lesions as "definite FNH," "possible FNH," or "definitely not FNH." Sensitivity (Se) and specificity (Spe) were compared between the two sets; subgroup analyses according to the lesion's size were performed.

RESULTS

Regardless of lesion size, the respective Se and Spe of both datasets were not statistically different (95.7 and 100% vs. 76.1 and 94.6% for set-1 and -2 respectively; p = 0.18). For lesions larger than 35 mm, although both sets had similar specificity (100%), sensitivity was higher for SET-1 (100% vs. 40%); p = 0.04. Tumor classifications using SET-1 and SET-2 could have changed patient management in 35/54 (64.8%) and 33/54 (61.1%) of all patients, respectively.

CONCLUSIONS

HBP-MRI or CEUS should be performed after an inconclusive CE-MRI. Both can change patient management by avoiding unnecessary biopsy or surveillance. The use of HBP-MRI should be advocated over CEUS in larger (>35 mm) lesions.

Imaging of Hepatic Focal Nodular Hyperplasia: Pictorial Review and Diagnostic Strategy

Focal nodular hyperplasia (FNH) is the second most common benign solid liver lesion after hemangioma, occurring more frequently in young women. The prime differential diagnoses include hepatocellular adenoma, hepatocellular carcinoma, and hypervascular metastasis. As the management of FNH is typically conservative, imaging plays a key role in diagnostic pathway, and misdiagnosis may have a major clinical effect. In this article, we describe the ultrasound, computed tomography, and magnetic resonance imaging features of FNH, underlining the importance of typical radiological features that allow a specific noninvasive diagnosis. We present a large spectrum of a typical imaging findings that FNH may present and discuss the up-to-date diagnostic strategy.