Contrast-enhanced ultrasound for the diagnosis of hepatic adenoma

A Scoping Review of the Classification, Diagnosis, and Management of Hepatic Adenomas

BACKGROUND

Hepatic adenomas (HA), or hepatocellular adenomas, are benign, solid liver lesions that develop in otherwise normal livers, often in the setting of increased estrogen levels. While considered a benign tumor, there is a risk for substantial complications such as hemorrhage and malignant transformation. We review the diagnosis, classification, and potential therapeutic management options for patients with HA.

METHODS

A scoping narrative review was conducted based on recent literature regarding classification, diagnosis, and management of HA.

RESULTS

While HAs are typically considered benign, complications such as hemorrhage and malignant transformation may occur in approximately 25% and 5% of patients, respectively. Recent advances in imaging and molecular profiling have allowed for the classification of HAs into subtypes allowing for patient risk stratification that helps guide management. Surgical resection should be considered in asymptomatic patients who are male, have an adenoma ≥5 cm in diameter, or have the β-catenin-activated subtype due to an increased risk of hemorrhage and/or malignant transformation.

CONCLUSION

Molecular profiling has aided in the stratification of patients relative to the risk of complications to predict better the potential behavior of HAs.

The diagnostic value of contrast-enhanced ultrasound (CEUS) for assessing hepatocellular carcinoma compared to histopathology; a retrospective single-center analysis of 119 patients1

BACKGROUND

HCC as the 6th most common tumor entity with the fourth highest mortality and an increasing prevalence especially due to today's lifestyle acquires a high attention in the clinical setting. Beside CECT and CEMRI, CEUS depicts a dynamic, low-risk and radiation free imaging method that finds its use mainly in screening and active surveillance programs.

PURPOSE

The aim of the retrospective study was to evaluate the diagnostic value of CEUS in correlation to pathologic findings.

MATERIALS AND METHODS

Between 2004 and 2018 a total number of 119 patients were included in this retrospective single-center study. Every patient underwent CEUS in addition to a native B-mode and Color-Doppler scan. After given informed consent SonoVue® (Bracco, Milan, Italy), a second-generation blood-pool agent, was used as contrast medium. Every examination was performed and interpreted by a single experienced radiologist (EFSUMB level 3). A low mechanical index (MI) of <0,2 was chosen to obtain a good imaging quality.

RESULTS

All 119 included patients received CEUS followed by a liver biopsy for inter-modality comparison. In correlation to the pathology results, CEUS showed a diagnostic sensitivity of 96,6%, a specificity of 63,9%, a PPV of 86,7% and a NPV of 88,5% by detecting liver lesions suspicious for HCC. According to the Cohen's Kappa coefficient (k = 0,659) CEUS shows a strong inter-modality agreement in comparison to the histopathological finding.

CONCLUSION

With a high sensitivity and a strong cross-modality comparability to histopathology, the CEUS is highly effective in the detection of suspicious HCC lesions.

Contrast-enhanced ultrasound approach to the diagnosis of focal liver lesions: the importance of washout

Contrast-enhanced ultrasound (CEUS) is a powerful technique for differentiating focal liver lesions (FLLs) without the risks of potential nephrotoxicity or ionizing radiation. In the diagnostic algorithm for FLLs on CEUS, washout is an important feature, as its presence is highly suggestive of malignancy and its characteristics are useful in distinguishing hepatocellular from nonhepatocellular malignancies. Interpreting washout on CEUS requires an understanding that microbubble contrast agents are strictly intravascular, unlike computed tomography or magnetic resonance imaging contrast agents. This review explains the definition and types of washout on CEUS in accordance with the 2017 version of the CEUS Liver Imaging Reporting and Data System and presents their applications to differential diagnosis with illustrative examples. Additionally, we propose potential mechanisms of rapid washout and describe the washout phenomenon in benign entities.

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.

Hepatocellular adenoma: comparison between real-time contrast-enhanced ultrasound and dynamic computed tomography

Purpose

To investigate and compare the contrast-enhanced ultrasound (CEUS) features of histologically proven HCA with those of contrast-enhanced computed tomography (CECT).

Methods

Eighteen patients with proven hepatic adenoma by pathology were retrospectively selected from the CEUS database. Fourteen of them had undergone liver CECT exams. The basic features on unenhanced imaging and the enhancement level and specific features on contrast-enhanced imaging were retrospectively analyzed, and the differences between CEUS and CECT were compared.

Results

All the HCAs showed hyper-enhancement in the arterial phase. During the portal and late phases, 12 HCAs (12/18, 66.7 %) on CEUS and 11 (11/14, 78.6 %) on CT showed washout. On CEUS, 10 (10/18, 55.5 %) showed centripetal filling in the arterial phase and persistent peripheral rim enhancement. Five of them (61.1 %, 11/18) showed delayed central washout in the portal or late phase. However, on CECT, 2 (14.3 %, 2/14) and 4 (28.6 %, 4/14) HCAs showed persistent enhancement of the peripheral rim and central non-enhancing hemorrhage areas, respectively.

Conclusions

Compared with dynamic CT, CEUS was superior at characterizing specific dynamic features. Considering that it is radiation-free, readily availability and easy to use, CEUS is suggested as the first line imaging tool to diagnose HCA.

Benign liver lesions: grey-scale and contrast-enhanced ultrasound appearances

Ultrasound is often the first point of detection of liver lesions, with up to 75% of liver lesions detected at ultrasound having benign histology. In 2012, NICE issued recommendations that ultrasound contrast be used for the evaluation of incidentally discovered liver lesions. This has been demonstrated to provide a rapid and cost-effective evaluation for incidental liver lesions, in many cases precluding the need for further CT or MRI scans. The aim of this review is to demonstrate the ultrasound features of benign liver lesions, and to demonstrate their further characterisation with contrast ultrasound.

Differentiation of focal nodular hyperplasia from hepatocellular adenomas with low-mechanical-index contrast-enhanced sonography (CEUS): effect of size on diagnostic confidence

PURPOSE

The purpose of this study was to assess the diagnostic performance of contrast-enhanced sonography (CEUS) for the differentiation of focal nodular hyperplasia (FNH) from hepatocellular adenoma (HCA) according to lesion size.

MATERIALS AND METHODS

Forty patients with a definite diagnosis of FNH or HCA who underwent CEUS were included in this institutional review board (IRB)-approved study. A total of 43 FNHs and 20 HCAs, including 15 inflammatory HCAs and five unclassified HCAs, were analysed. Two radiologists reviewed the diagnostic CEUS parameters separately and in consensus, including the presence or absence of centrifugal filling and central vessels. The sensitivity (Se), specificity (Sp), and inter-observer confidence (Kappa) of CEUS diagnostic parameters were assessed.

RESULTS

Inter-observer agreement of CEUS for FNH diagnosis was high (kappa = 0.81) with an overall Se of 67.4% [29/43 (CI 95%: 51.4-80.1 %)] and an Sp of 100% [20/20 (CI 95%: 81-100%)]. Significantly higher Se figures were found for lesions ≤ 35 mm than for lesions > 35 mm [respectively, 93 % (28/30) (CI 95%: 77.6-99.2) vs. 7.7% (1/13) (CI 95%: 0.2-36%), p = 0.002] with unchanged specificity.

CONCLUSION

CEUS is highly specific for the diagnosis of FNH, with very good inter-observer agreement, whatever the size, but its sensitivity is significantly reduced in diagnosing lesions larger than 35 mm.

KEY POINTS

• CEUS is highly specific for the diagnosis of FNH, regardless of lesion size • CEUS shows reduced sensitivity in diagnosing FNH lesions larger than 35 mm • The filling patterns of hepatocellular adenomas are not affected by lesion size.

Contrast-Enhanced Ultrasound for the differentiation of benign and malignant focal liver lesions: a meta-analysis

BACKGROUND

International guidelines of Ultrasound recommend the performance of contrast-enhanced ultrasound (CEUS) as the first method of choice after conventional ultrasound for the diagnostic work-up of focal liver lesions. However, these recommendations are based on the results of multiple single studies and only few large multicentre studies.

AIMS

The rationale of the present systematic review and meta-analysis was to assess the overall sensitivity and specificity of CEUS for the diagnosis of malignant liver lesions.

METHODS

Literature databases were searched up to March 2012. Inclusion criteria were evaluation of CEUS, assessment of sensitivity and specificity of CEUS for the diagnosis of malignant liver lesions. The meta-analysis was performed using the random-effects model based on the DerSimonian Laird method. Quality analyses were carried out to assess sources of heterogeneity.

RESULTS

A total of 45 studies with 8147 focal liver lesions were included in the analysis. Overall sensitivity and specificity of CEUS for the diagnosis of malignant liver lesions was 93% (95%-CI: 91-95%) and 90% (95%-CI: 88-92%) respectively. Significant heterogeneity was found between studies. However, subanalysis revealed no significant difference when evaluating studies using histology for all liver lesions, when comparing high-quality and low-quality studies, and blinded vs non-blinded studies.

CONCLUSION

The results of this meta-analysis support the international recommendations on CEUS for the diagnostic work-up of focal liver lesions selecting patients who need further diagnostics.