Liver tumor characterization--comments and illustrations regarding guidelines

Incidental Findings in Pediatric Patients: How to Manage Liver Incidentaloma in Pediatric Patients

The World Federation for Ultrasound in Medicine and Biology (WFUMB) is addressing the issue of incidental findings (IFs) with a series of publications entitled "Incidental imaging findings-the role of ultrasound". IFs in the liver of newborns and children are rare and much less commonly encountered than in adults; as a result, they are relatively much more frequently malignant and life-threatening, even when they are of benign histology. Conventional B-mode ultrasound is the well-established first line imaging modality for the assessment of liver pathology in pediatric patients. US technological advances, resulting in image quality improvement, contrast-enhanced ultrasound (CEUS), liver elastography and quantification tools for steatosis have expanded the use of ultrasound technology in daily practice. The following overview is intended to illustrate incidentally detected liver pathology covering all pediatric ages. It aims to aid the examiner in establishing the final diagnosis. Management of incidentally detected focal liver lesions (FLL) needs to take into account the diagnostic accuracy of each imaging modality, the patient's safety issues (including ionizing radiation and nephrotoxic contrast agents), the delay in diagnosis, the psychological burden on the patient and the cost for the healthcare system. Moreover, this paper should help the pediatric clinician and ultrasound practitioner to decide which pathologies need no further investigation, which ones require interval imaging and which cases require further and immediate diagnostic procedures.

Contrast-Enhanced Ultrasound as a Main Radiological Diagnostic Method for Primary Liver Neoplasms and Hemangiomas

Contrast-enhanced ultrasound (CEUS) is a relatively new approach for the definitive diagnosis of focal liver lesions (FLL). The essential advantages of CEUS are affordability, absence of radiation, and negligible nephrotoxicity-making this diagnostic approach more preferable.

This review includes data from 39 different research studies published during the last 10 years, selected through the MeSH strategy in PubMed.

We conclude that CEUS is a promising approach for diagnosing primary liver neoplasms and it is an excellent radiological approach for children and pregnant women because of the absence of radiation and nephrotoxicity. Studies showed that CEUS is a very good approach for the differentiation of a variety of hemangiomas and for a detailed description of those findings. Therefore, CEUS is an important and progressive method for the diagnosis of liver neoplasms. The regular use of CEUS will facilitate the diagnosis of primary liver lesions.

Current Opinion about Hepatocellular Carcinoma <10 mm

BACKGROUND

Early detection of hepatocellular carcinoma (HCC) is important. Advances in liver imaging techniques have facilitated the detection of HCC at an early stage. However, there is a controversial discussion on how to diagnose very small HCC by imaging. The aim of the current review is to present current published data on HCC ≤10 mm and discuss on how to best diagnose and treat such lesions.

SUMMARY

It is still challenging, however, to accurately characterize HCC <10 mm. The accuracy of contrast-enhanced ultrasound may be critical for early treatment decisions for cancer patients, particularly when CECT and/or CEMRI are inconclusive. Key Messages: The characterization of focal liver lesions <10 mm is frequently delayed until a follow-up imaging procedure demonstrates growth or stability. A repetition of ultrasound examination after 3 months for new nodules <1 cm should be recommended.

Diagnostic accuracy of ultrasound superb microvascular imaging for focal liver lesions: A protocol for systematic review and meta-analysis

BACKGROUND

Superb microvascular imaging (SMI) is a new ultrasound vascular imaging technology, which uses a new Doppler algorithm, it has the characteristics of high sensitivity and high resolution to detect low velocity blood flow; it is easier to detect microvessels with low-velocity flow compared with color Doppler flow imaging in theory; and it can image the microvessels of the lesion without angiography.[1] Previous studies showed that SMI can detect tumor neovascularization to differentiate benign from malignant focal liver lessions (FLLs). However, the results of these studies have been contradictory with low sample sizes. This meta-analysis tested the hypothesis that SMI is accurate in distinguishing benign and malignant FLLs.

METHODS

We will search PubMed, Web of Science, Cochrane Library, and Chinese biomedical databases from their inceptions to the November 30, 2020, without language restrictions. Two authors will independently carry out searching literature records, scanning titles and abstracts, full texts, collecting data, and assessing risk of bias. Review Manager 5.2 and Stata14.0 software will be used for data analysis.

RESULTS

This systematic review will determine the accuracy of SMI in the differential diagnosis between benign and malignant FLLs.

CONCLUSION

Its findings will provide helpful evidence for the accuracy of SMI in the differential diagnosis between benign and malignant FLLs.

SYSTEMATIC REVIEW REGISTRATION

INPLASY2020120081.

Diagnostic Value of CEUS Prompting Liver Biopsy: Histopathological Correlation of Hepatic Lesions with Ambiguous Imaging Characteristics

Background: Contrast-enhanced ultrasound (CEUS) allows for dynamic analysis of vascularization patterns of unclear hepatic lesions. Our study aimed to evaluate the diagnostic performance of CEUS for further characterizing suspicious liver lesions by comparing findings from CEUS examinations with corresponding histopathology. Methods: Between 2005 and 2016, 160 patients with unclear liver lesions underwent CEUS followed by liver biopsy. All examinations were performed by an experienced consultant radiologist (EFSUMB Level 3) and included native B-mode ultrasound, Color Doppler, and CEUS. A second-generation blood pool contrast agent was applied for CEUS. Results: CEUS was successfully performed in all patients without occurrence of any adverse side effects. CEUS showed a sensitivity of 94.5%, a specificity of 70.6%, a true positive rate of 87.3%, and a true negative rate of 85.7% compared to histopathological results as the reference standard. Conclusions: CEUS represents a safe imaging modality with a high diagnostic accuracy in assessing both—benign and malignant—liver lesions compared to corresponding histopathological results.

Diagnostic approach in hepatic lymphoma: radiological imaging findings and literature review

PURPOSE

Imaging manifestations of hepatic lymphoma, both primary (PHL) and secondary (SHL), are extremely variable and non-specific, but some features are useful diagnostic clues in an appropriate clinical setting. Through a PubMed search, we found several published reviews focused on PHL and SHL diagnosis. However, to the best of our knowledge, few of them encompass a comprehensive analysis of all the diagnostic tools and relative radiological findings. The aim of this review is to provide a description of the radiological features of both PHL and SHL, by critically analyzing the available literature.

MATERIALS AND METHODS

An extensive review of published literature along with a description of personal case series of both PHL and SHL has been conducted.

RESULTS

SHL can be easily diagnosed with imaging techniques, as it is usually associated with node disease. On the contrary the diagnosis can be a challenge in PHL, often mimicking HCC or liver metastasis of adenocarcinoma. In this context, multiparametric MRI plays a fundamental role in the differential diagnosis. Both for PHL and SHL, liver involvement presents as solitary or multiple lesions or as diffuse infiltrative disease.

CONCLUSION

PHL and SHL may be correctly characterized using different radiological techniques. Both CT and MRI have showed a good correlation with histology, as they permit to distinguish between lymphomatous tissue, and necrotic and fibrotic areas.

Contrast-enhanced ultrasound in the diagnosis of pediatric focal nodular hyperplasia and hepatic adenoma: interobserver reliability

BACKGROUND

Focal nodular hyperplasia and hepatic adenoma are rare liver tumors in which specific features on contrast-enhanced ultrasound (US) have been reported but are little known in children.

OBJECTIVE

To assess the interobserver agreement in diagnosing and differentiating focal nodular hyperplasia and hepatic adenoma in children using established adult contrast-enhanced US characteristics.

MATERIALS AND METHODS

Thirty children with a definite or probable diagnosis of focal nodular hyperplasia or hepatic adenoma on magnetic resonance imaging (MRI)/histology who underwent contrast-enhanced US studies were included. Typical and additional contrast-enhanced US features of focal nodular hyperplasia and hepatic adenoma were included. The lesions were classified as definite/probable focal nodular hyperplasia, definite/probably hepatic adenoma or unclassified. The interobserver kappa of contrast-enhanced US characteristics was calculated.

RESULTS

Focal nodular hyperplasia and hepatic adenoma in children demonstrate contrast-enhanced US characteristics similar to those in adults. Among the nine lesions with confirmed histological diagnosis, correct diagnosis was made in 7 (77.8%) based on contrast-enhanced US criteria. Two lesions were unclassified by both observers due to a mixed arterial filling pattern. Interobserver kappa for contrast-enhanced US diagnosis was 0.64 (P<0.0001).

CONCLUSION

There is a good interobserver kappa for separating focal nodular hyperplasia from hepatic adenoma in children using established adult contrast-enhanced US features.

Standardisierte Befundung und Dokumentation der Kontrastmittelsonografie der Leber (CEUS LI-RADS)

In der Abklärung von hepatozellulären Karzinomen (HCCs) bei Hochrisikopatienten wurde zur standardisierten Befundung und Dokumentation der Kontrastmittel-Computertomografie (CECT) und Kontrastmittel-Magnetresonanztomografie (CEMRT) vor wenigen Jahren das „Liver Imaging Reporting and Data System” (LI-RADS) durch das American College of Radiology (ACR) erstellt. Die LI-RADS-Kategorisierung wird zur Klassifikation von Leberläsionen in der Leberzirrhose als sicher benigne (LR-1), intermediär (LR2 – 4) bis zu „definitiv HCC“ (LR-5) beurteilt. Seit 2014 wurde die LI-RADS-Klassifikation durch eine Arbeitsgruppe von internationalen Radiologen und Hepatologen auf die Kontrastmittelsonografie erweitert. Zeitgleich mit der Zulassung des Kontrastmittels SonoVue™ (in den USA Lumason™) wurde die Klassifikation 2016 in die LI-RADS Kategorisierung integriert und wird in diesem Artikel erläutert (CEUS-LI-RADS).

Application of superb microvascular imaging in focal liver lesions

AIM

To explore the ability of superb microvascular imaging (SMI) in differential diagnosis of focal liver lesions (FLLs) and to compare SMI morphology findings to those of color Doppler ultrasound and enhanced imaging.

METHODS

Twenty-four patients with 31 FLLs were included in our study, with diagnoses of hemangioma (HE) (n = 17), hepatocellular carcinoma (HCC) (n = 5), metastatic lesions (n = 5), primary hepatic lymphoma (n = 1), focal nodular hyperplasia (FNH) (n = 2), and adenoma (n = 1). Nine lesions were pathologically diagnosed, and 22 lesions were radiologically confirmed, all of which were evaluated by at least two types of enhanced imaging techniques. All patients had undergone SMI. Patients were divided into subgroups based on pathological and radiological diagnoses to analyze SMI manifestations. We also compared the SMI manifestations of the most common malignant FLLs (HCCs and metastatic lesions) with those of the most common benign FLLs (HEs).

RESULTS

HEs were classified into three SMI subgroups: diffuse dot-like type (n = 6), strip rim type (n = 8), and nodular rim type (n = 3). The sizes of the three types of HEs were significantly different (P = 0.00, < 0.05). HCCs were classified into two subgroups: diffuse honeycomb type (n = 2) and non-specific type (n = 3). Four of the metastatic lesions were the strip rim type, and the other metastatic lesion was the thick rim type, which is the same as that of lymphoma. FNH was described as a spoke-wheel type, and adenoma as a diffuse honeycomb type. The SMI types of HCCs and metastatic lesions were significantly different from those of HEs (P = 0.048, < 0.05).

CONCLUSION

SMI technology enables microvascular evaluation of FLLs without using any contrast agent. For HEs, lesion size may affect SMI performance. SMI is able to provide useful information for differential diagnosis of HCCs and metastatic lesions from HEs.

Characterization of Focal Liver Lesions Indistinctive on B Mode Ultrasound: Benefits of Contrast-Enhanced Ultrasound

Aim. The aim of this prospective study was to evaluate the additional value of contrast-enhanced ultrasound (CEUS) in identifying and characterizing of focal liver lesions (FLLs) that are indistinctive on B mode ultrasound (BMUS). Methods. The study focused on 70 consecutive patients (male 46, female 24; mean age, 53.1 years ± 10). All lesions were detected by MRI but could not be clearly visualized by BMUS. CEUS was performed by injected SonoVue® (Bracco Imaging Spa, Milan, Italy) as a quick bolus into the antecubital vein. All lesions were proved by pathologic and MRI findings as primary or metastatic hepatic malignancies. Results. On CEUS, 45 (64.2%) FLLs displayed arterial hyperenhancement and 55 (78.5%) lesions showed hypoenhancement in portal venous and late phase (PVLP). Homogeneous and complete hyperenhancement pattern during the arterial phase is highly suspicious for HCC in liver cirrhosis (96.8%). Arterial isoenhancement and early washout during PVLP are characteristic for metastasis (73.3%). For recurrence lesions, arterial hyperenhancement and isoenhancement during PVLP are more common (60%). Conclusion. CEUS may provide added diagnostic values in FLLs appearing indistinctive on BMUS. Presence of early arterial enhancement and washout during PVLP may be helpful for detection of those lesions.

Contrast enhanced ultrasound features of hepatic cystadenoma and hepatic cystadenocarcinoma

OBJECTIVE

Hepatic (biliary) cystic tumor (HBCT) is a rare focal cystic liver lesion, which has been rarely described in the literature. In our current multicenter, retrospective study, we aimed to analyze contrast enhanced ultrasound (CEUS) features and its diagnostic performance in histologically proved HBCT.

MATERIAL AND METHODS

Twenty-three patients with single HBCT were retrospectively analyzed. Histologically, 17 (73.9%) were benign hepatic (biliary) cystadenoma (HBCA), 6 (26.1%) were hepatic (biliary) cystadenocarcinoma (HBCAC). All CEUS examinations were assessed by two independent radiologists in consensus. Criteria of CEUS imaging evaluation included the contrast enhancement pattern of lesion (hypoenhancing, hyperenhancing, isoenhancing in comparison to the surrounding liver parenchyma) during the arterial, portal venous and late phases.

RESULTS

After injection of ultrasound contrast agents, most of the HBCTs (78.3%, 18/23) had typical honeycomb enhancement pattern of the cystic wall, septa or mural nodules. Comparing between HBCA and HBCAC, hyperenhancement of the honeycomb septa during the arterial phase was more common in HBCA (p = .047). However, hypoenhancement during the portal venous and late phases was the characteristic of HBCAC (p = .041).

CONCLUSIONS

The EFSUMB algorithm for CEUS for characterization of solid focal liver lesions is also applicable to HBCT. CEUS evaluation can avoid further diagnostic investigations or invasive biopsy procedure.

Dynamic contrast-enhanced endoscopic ultrasound: A quantification method

Dynamic contrast-enhanced ultrasound (DCE-US) has been recently standardized by guidelines and recommendations. The European Federation of Societies for US in Medicine and Biology position paper describes the use for DCE-US. Comparatively, little is known about the use of contrast-enhanced endoscopic US (CE-EUS). This current paper reviews and discusses the clinical use of CE-EUS and DCE-US. The most important clinical use of DCE-US is the prediction of tumor response to new drugs against vascular angioneogenesis.

Contrast-enhanced ultrasound features of histologically proven small (≤20 mm) liver metastases

OBJECTIVE

We analyzed contrast-enhanced ultrasound (CEUS) features of histologically proved small (≤20 mm) liver metastases, in comparison to small (≤20 mm) hepatocellular carcinomas (HCC), to define the differentiate diagnoses value of CEUS in clinical practice.

MATERIAL AND METHODS

Eighty-two cases of small (≤20 mm) liver metastases and 84 cases of small (≤20 mm) HCC were retrospectively reviewed. All patients had CEUS images. Two radiologists assessed CEUS enhancement pattern and time of enhancement in consensus. Statistical analyses were performed using SPSS v.19.0 (SPSS Inc., Chicago, IL). The χ² test and the independent sample t-test were used to compare the differences.

RESULTS

Comparing to small HCCs, rapid rim-like hyper-enhancement in arterial phase (56.1% in liver metastases vs. 2.3% in HCCs, p < .01), rapid wash-out and become hypo-enhancement in late arterial phase or early portal venous phase (96.4% in liver metastases vs. 22.6% in HCCs, p < .01) with central non-enhanced area in late phase were characteristic CEUS features of small metastases.

CONCLUSIONS

CEUS imaging enhancement findings reliably offer typical signs of small liver metastases, differentiate effectively with small HCCs. CEUS can help to improve the diagnostic confidence of small liver metastases.

Contrast-enhanced ultrasound of histologically proven hepatic epithelioid hemangioendothelioma

AIM: To analyze contrast-enhanced ultrasound (CEUS) features of histologically proven hepatic epithelioid hemangioendothelioma (HEHE) in comparison to other multilocular benign focal liver lesions (FLL).

METHODS: Twenty-five patients with histologically proven HEHE and 45 patients with histologically proven multilocular benign FLL were retrospectively reviewed. Four radiologists assessed the CEUS enhancement pattern in consensus.

RESULTS: HEHE manifested as a single (n = 3) or multinodular (n = 22) FLL. On CEUS, HEHE showed rim-like (18/25, 72%) or heterogeneous hyperenhancement (7/25, 28%) in the arterial phase and hypoenhancement (25/25, 100%) in the portal venous and late phases (PVLP), a sign of malignancy. Eighteen patients showed central unenhanced areas (18/25, 72%); in seven patients (7/25, 28%), more lesions were detected in the PVLP. In contrast, all patients with hemangioma and focal nodular hyperplasia showed hyperenhancement as the most distinctive feature (P < 0.01).

CONCLUSION: CEUS allows for characterization of unequivocal FLL. By analyzing the hypoenhancement in the PVLP, CEUS can determine the malignant nature of HEHE.

Benign liver tumors in pediatric patients - Review with emphasis on imaging features

Benign hepatic tumors are commonly observed in adults, but rarely reported in children. The reasons for this remain speculative and the exact data concerning the incidence of these lesions are lacking. Benign hepatic tumors represent a diverse group of epithelial and mesenchymal tumors. In pediatric patients, most benign focal liver lesions are inborn and may grow like the rest of the body. Knowledge of pediatric liver diseases and their imaging appearances is essential in order to make an appropriate differential diagnosis. Selection of the appropriate imaging test is challenging, since it depends on a number of age-related factors. This paper will discuss the most frequently encountered benign liver tumors in children (infantile hepatic hemangioendothelioma, mesenchymal hamartoma, focal nodular hyperplasia, nodular regenerative hyperplasia, and hepatocellular adenoma), as well as a comparison to the current knowledge regarding such tumors in adult patients. The current emphasis is on imaging features, which are helpful not only for the initial diagnosis, but also for pre- and post-treatment evaluation and follow-up. In addition, future perspectives of contrast-enhanced ultrasound (CEUS) in pediatric patients are highlighted, with descriptions of enhancement patterns for each lesion being discussed. The role of advanced imaging tests such as CEUS and magnetic resonance imaging, which allow for non-invasive assessment of liver tumors, is of utmost importance in pediatric patients, especially when repeated imaging tests are needed and radiation exposure should be avoided.

Hepatosplenic sarcoidosis: contrast-enhanced ultrasound findings and implications for clinical practice

Sarcoidosis is a complex granulomatous disease that affects virtually every organ and tissue, with a prevalence that varies significantly among the sites involved. The role of conventional imaging, such as computed tomography and magnetic resonance imaging, in the assessment of hepatosplenic sarcoidosis is well established by revealing organ enlargement, multiple discrete nodules, and lymphadenopathy. In this review, we aim to describe contrast-enhanced ultrasound (CEUS) findings in liver and spleen involvement by sarcoidosis, reporting evidence from the literature and cases from our experience, after a brief update on safety profile, cost-effectiveness, and clinical indications of this novel technique. Furthermore, we highlight potential advantages of CEUS in assessing hepatosplenic sarcoidosis that may be useful in the clinical practice.

Liver elastography, comments on EFSUMB elastography guidelines 2013

Recently the European Federation of Societies for Ultrasound in Medicine and Biology Guidelines and Recommendations have been published assessing the clinical use of ultrasound elastography. The document is intended to form a reference and to guide clinical users in a practical way. They give practical advice for the use and interpretation. Liver disease forms the largest section, reflecting published experience to date including evidence from meta-analyses with shear wave and strain elastography. In this review comments and illustrations on the guidelines are given.

Fortuitously discovered liver lesions

The fortuitously discovered liver lesion is a common problem. Consensus might be expected in terms of its work-up, and yet there is none. This stems in part from the fact that there is no preventive campaign involving the early detection of liver tumors other than for patients with known liver cirrhosis and oncological patients. The work-up (detection and differential diagnosis) of liver tumors comprises theoretical considerations, history, physical examination, laboratory tests, standard ultrasound, Doppler ultrasound techniques, contrast-enhanced ultrasound (CEUS), computed tomography and magnetic resonance imaging, as well as image-guided biopsy. CEUS techniques have proved to be the most pertinent method; these techniques became part of the clinical routine about 10 years ago in Europe and Asia and are used for a variety of indications in daily clinical practice. CEUS is in many cases the first and also decisive technical intervention for detecting and characterizing liver tumors. This development is reflected in many CEUS guidelines, e.g., in the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) guidelines 2004, 2008 and 2012 as well as the recently published World Federation for Ultrasound in Medicine and Biology-EFSUMB guidelines 2012. This article sets out considerations for making a structured work-up of incidental liver tumors feasible.

Contrast-enhanced ultrasound features of histologically proven focal nodular hyperplasia: diagnostic performance compared with contrast-enhanced CT

OBJECTIVES

To investigate and compare contrast-enhanced ultrasound (CEUS) in the characterisation of histologically proven focal nodular hyperplasia (FNH) with contrast-enhanced computed tomography (CECT).

METHODS

CEUS was performed in 85 patients with 85 histologically proven FNHs. Enhancement, centrifugal filling, spoke-wheel arteries, feeding artery and central scarring were reviewed and correlated with lesion size or liver background. Independent factors for predicting FNH from other focal liver lesions (FLLs) were evaluated. Forty-seven FLLs with CECT were randomly selected for comparison of diagnostic performance with CEUS.

RESULTS

Centrifugal filling was more common (P = 0.002) and the significant predictor (P = 0.003) in FNHs ≤3 cm. Lesion size or liver background has no significant influence on the detection rate of the spoke-wheel arteries and feeding artery (P > 0.05). Central scarring was found in 42.6 % of FNHs ≥3 cm (P = 0.000). The area under the ROC curve, sensitivity and specificity showed no significant differences between CEUS and CECT (P > 0.05), except that the sensitivity of CEUS was better for reader 1 (P = 0.041).

CONCLUSION

CEUS is valuable in characterising centrifugal filling signs or spoke wheels in small FNHs and should be employed as the first-line imaging technique for diagnosis of FNH.

KEY POINTS

• The confident diagnosis of focal nodular hyperplasia is important in liver imaging. • The centrifugal filling sign is useful for diagnosis of FNHs ≤3 cm. • Contrast-enhanced ultrasound and contrast-enhanced CT have similar diagnostic performance for FNH. • CEUS should be the first-line imaging technique for the diagnosis of FNH.

Contrast-enhanced endoscopic ultrasound

The European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) introduced guidelines on the use of contrast-enhanced ultrasound (CEUS) in 2004. This EFSUMB-document focused mainly on liver applications. However, new applications extending beyond the liver were developed thereafter. Increased interest in recent years in CEUS technique and in the application of CEUS in novel fields like endoscopic ultrasound (EUS) has revolutionized indications and applications. As a result, the EFSUMB initiated a new update of the guidelines in 2011 to include this additional knowledge. Some of the contrast-enhanced EUS (CE-EUS) indications are established, whereas others are preliminary; these latter indications are categorized as emergent CEUS applications since the available evidence is insufficient for general recommendation. This article focuses on the use of CE-EUS in various clinical settings. The reader will get an overview of current indications and possible applications of CE-EUS. This involves the introduction of different contrast studies including color Doppler techniques (known as contrast-enhanced high mechanical index endosonography or CEHMI-EUS) as well as more modern high-resolution contrast-enhanced techniques (known as contrast-enhanced low mechanical index endosonography or CELMI EUS).