European Federation Of Societies For Ultrasound In Medicine And Biology Research Articles

Contrast-enhanced ultrasound (CEUS): applications from the kidneys to the bladder.

Contrast-enhanced ultrasound (CEUS) is an advanced ultrasound (US) technique utilizing ultrasound contrast agents (UCAs) to provide detailed visualization of anatomic and vascular architecture, including the depiction of microcirculation. CEUS has been well-established in echocardiography and imaging of focal hepatic lesions and recent studies have also shown the utility of CEUS in non-hepatic applications like the urinary system. The updated guidelines by the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) from 2018 describe the use of CEUS for non-hepatic applications. CEUS' excellent safety profile and spatial resolution make it a superior modality to conventional US and is often comparable and even superior to CECT in some instances. In comparison to other cross-sectional imaging modalities such as CECT or MRI, CEUS offers a safe (by virtue of non-nephrotoxic US contrast agents), accurate, cost-efficient, readily available, and a quick means of evaluation of multiple pathologies of the urinary system. CEUS also has the potential to reduce the overall economic burden on patients requiring long-term follow-up due to its low cost as compared to CT or MRI techniques. This comprehensive review focuses on the applications of CEUS in evaluating the urinary system from the kidneys to the urinary bladder. CEUS can be utilized in the kidney to evaluate complex cystic lesions, indeterminate lesions, pseudotumors (vs solid renal tumors), renal infections, and renal ischemic disorders. Additionally, CEUS has also been utilized in evaluating renal transplants. In the urinary bladder, CEUS is extremely useful in differentiating a bladder hematoma and bladder cancer when conventional US techniques show equivocal results. Quantitative parameters of time-intensity curves (TICs) of CEUS examinations have also been studied to stage and grade bladder cancers. Although promising, further research is needed to definitively stage bladder cancers and classify them as muscle-invasive or non-muscle invasive using quantitative CEUS to guide appropriate intervention. CEUS has been very effective in the classification of cystic renal lesions, however, further research is needed in differentiating benign from malignant renal masses.

EFSUMB Technical Review - Update 2023: Dynamic Contrast-Enhanced Ultrasound (DCE-CEUS) for the Quantification of Tumor Perfusion.

Dynamic contrast-enhanced ultrasound (DCE-US) is a technique to quantify tissue perfusion based on phase-specific enhancement after the injection of microbubble contrast agents for diagnostic ultrasound. The guidelines of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) published in 2004 and updated in 2008, 2011, and 2020 focused on the use of contrast-enhanced ultrasound (CEUS), including essential technical requirements, training, investigational procedures and steps, guidance regarding image interpretation, established and recommended clinical indications, and safety considerations. However, the quantification of phase-specific enhancement patterns acquired with ultrasound contrast agents (UCAs) is not discussed here. The purpose of this EFSUMB Technical Review is to further establish a basis for the standardization of DCE-US focusing on treatment monitoring in oncology. It provides some recommendations and descriptions as to how to quantify dynamic ultrasound contrast enhancement, and technical explanations for the analysis of time-intensity curves (TICs). This update of the 2012 EFSUMB introduction to DCE-US includes clinical aspects for data collection, analysis, and interpretation that have emerged from recent studies. The current study not only aims to support future work in this research field but also to facilitate a transition to clinical routine use of DCE-US.

Intra- and Interobserver Study Investigating the Adapted EFSUMB Bosniak Cyst Categorization Proposed for Contrast-Enhanced Ultrasound (CEUS) in 2020.

To investigate the inter- and intraobserver variability in comparison to an expert gold standard of the new and modified renal cyst Bosniak classification proposed for contrast-enhanced ultrasound findings (CEUS) by the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) in 2020. 84 CEUS examinations for the evaluation of renal cysts were evaluated retrospectively by six readers with different levels of ultrasound expertise using the modified Bosniak classification proposed for CEUS. All cases were anonymized, and each case was rated twice in randomized order. The consensus reading of two experts served as the gold standard, to which all other readers were compared. Statistical analysis was performed using Cohen's weighted kappa tests, where appropriate. Intraobserver variability showed substantial to almost perfect agreement (lowest kappa κ=0.74; highest kappa κ=0.94), with expert level observers achieving the best results. Comparison to the gold standard was almost perfect for experts (highest kappa κ=0.95) and lower for beginner and intermediate level readers still achieving mostly substantial agreement (lowest kappa κ=0.59). Confidence of rating was highest for Bosniak classes I and IV and lowest for classes IIF and III. Categorization of cystic renal lesions based on the Bosniak classification proposed by the EFSUMB in 2020 showed very good reproducibility. While even less experienced observers achieved mostly substantial agreement, training remains a major factor for better diagnostic performance.

Development and implementation of a comprehensive ultrasound curriculum for medical students: The Bonn internship point-of-care-ultrasound curriculum (BI-POCUS).

Point-of-care ultrasound (POCUS) is rapidly gaining ground within different areas of applications. Despite the high and increasing relevance of ultrasound, the availability of structured training programs in medical schools is still limited. Therefore, many doctors keep acquiring all their ultrasound skills throughout their postgraduate training. As a result, new residents lack theoretical and practical ultrasound abilities that are critical in everyday clinical practice. In order to improve this, we created and implemented a complete ultrasound curriculum for all medical students throughout their internship year that focuses on hands-on abilities in ultrasound imaging. We used Kern's six-step model of curricular development comprising (1) problem identification and general needs assessment, (2) needs assessment of the targeted learners, (3) goals and objectives, (4) educational strategies, (5) implementation, and (6) evaluation and feedback by board-certified ultrasound experts. A two rounds Delphi process with multilevel, self-completed questionnaires and individual using a 9-point Likert scale and free text comments was used to identify learning objectives and reach agreement on the content of the curriculum. The curriculum developed is aimed at students with no or little experience in their internship year and will be taught as part of their weekly-based internship training courses consisting of 2 hours of theory and 3 hours of practical training. The training will be conducted within a modular framework focusing on the key requirements of POCUS with increasing levels of complexity in accordance with the recommendations of the German Society for Ultrasound in Medicine (DEGUM), the European Federation of Societies for ultrasound in Medicine and Biology (EFSUMB) and the World Federation for ultrasound in Medicine and Biology (WFUMB). A longitudinal e-learning system will be implemented in addition to the practical and theoretical teaching units to track and examine the progress of the students. Early integration of ultrasound training into medical education as part of a structured and standardized broad ultrasound curriculum enables medical students to acquire basic skills and apply them practically. Fundamental scanning skills are acquired by hands-on exercises in small, supervised groups as part of BI-POCUS. BI-POCUS therefore provides an excellent opportunity to improve the clinical skills of future physicians. More research is needed to analyze the learning outcomes for medical students and the improvement of the patient's outcome by establishing such an ultrasound curriculum.

Professional Standards in Medical Ultrasound - EFSUMB Position Paper (Short Version) - General Aspects.

This first position paper of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) on professional standards presents a common position across the different medical professions within EFSUMB regarding optimal standards for the performing and reporting of ultrasound examinations by any professional ultrasound operator. It describes general aspects of professionality that ensure procedure quality, effectiveness, efficiency, and sustainability in virtually all application fields of medical ultrasound. Recommendations are given related to safety and indication of ultrasound examinations, requirements for examination rooms, structured examination, systematic reporting of results, and management, communication and archiving of ultrasound data. The print version of this article is a short version. The long version is published online.

Professional Standards in Medical Ultrasound - EFSUMB Position Paper (Long Version) - General Aspects.

This first position paper of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) on professional standards presents a common position across the different medical professions within EFSUMB regarding optimal standards for the performing and reporting of ultrasound examinations by any professional ultrasound operator. It describes general aspects of professionality that ensure procedure quality, effectiveness, efficiency, and sustainability in virtually all application fields of medical ultrasound. Recommendations are given related to safety and indication of ultrasound examinations, requirements for examination rooms, structured examination, systematic reporting of results, and management, communication and archiving of ultrasound data. The print version of this article is a short version. The long version is published online.

Echoscopy in scanning cardiac diseases in critical care medicine.

Targeted ultrasound examinations with aportable ultrasound device ("handheld ultrasound system"; HHUS) have been defined as "echoscopy" by the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB). Cardiac scanning with HHUS is feasible. Echoscopy could play amajor role in emergency and intensive care medicine, but adequate data on its effectiveness are still lacking. Sonographic examinations in the field of emergency and intensive care medicine can often not be carried out under standardized examination conditions. Thus, the aim of this study is to show that the use of HHUS for echocardiography in emergency medicine is possible and that for this setting HHUS is not inferior to ahigh-end ultrasound system (HEUS) for detecting cardiac pathologies. The examinations were carried out with aVscan™ (GE Medical Systems, Solingen, Germany) and ahigh-end ultrasound device (Acuson X‑300 or X‑700). The examinations were randomized and blinded to two examiners within 30 min. The examinations took place in the intensive care unit, the emergency room and the ambulance service. The results were recorded in an examination sheet. In all, 93patients (61men and 32women, age 69 ± 14.76 [33-95]years). In 32.6% (30/93) of examinations with HEUS the examination conditions were optimal and in 29.03% (27/93) when the HHUS was used. Of the examinations, 50.08% (31/61) were carried out by both examiners in the same patient position. Using HHUS, the following sensitivity and specificities (respectively) were found: pericardial effusion (73.68%; 96.97%), hemodynamically relevant effusion (50%; 97.67%), right heart strain (90,91%; 96,72%), arrest of the right ventricle (100%; 87,5%), limitation of left ventricular pump function (91.49%; 86.11%), wall movement disorders (WMD, 97.29%; 78.95%), aortic valve sclerosis (42.86%; 86.67%), aortic regurgitation (60%; 95%), mitral valve sclerosis (60%; 100%), mitral reguritation (66.67%; 82.86%), tricuspid valve regurgitation (48%; 81,48%). Measurements of the dimensions of pericardial effusion, the left ventricle, the left atrium and the left ventricular posterior wall each had apositive correlation between the examination with HHUS and HEUS (Κ = 0.45 to 0.91). The diameters determined by HHUS and HEUS for the septum and aortic root, however, correlated negatively (κ = -0.61 to -0.86). The use of echoscopy in emergency and intensive care medicine is not inferior to HEUS for detecting defined cardiac pathologies.

Miniaturised ultrasound evaluation at the bedside

Purpose“Point-of-Care Ultrasound” (POCUS) is now a familiar term. Although the European Federation of Societies for Ultrasound in Medicine and Biology (ESFUMB) published a position paper about its usage (Nielsen et al. in Ultraschall Med 40(1):30–39. https://doi.org/10.1055/a-0783-2303, 2019), there has not been much scientific focus on its utility in uro-nephrological clinical practice thus far. The aim of this study was to evaluate the present usage of pocket ultrasound devices at the bedside.Methods27 investigators (all medical doctors with at least 6 months of experience in sonography) performed 280 bedside examinations using a pocket ultrasound device for common clinical issues.ResultsThe most frequent indications included evaluation of hydronephrosis (147), volume management including assessment of dimension of the vena cava inferior (IVC) (195), detection of pleural, pericardial and abdominal effusions (113) as well as residual urine (52). In 90%, specific clinical questions were effectively answered by the pocket ultrasound device alone.ConclusionsPOCUS can be useful in the uro-nephrological field. In the hands of an experienced investigator, it saves time and, when it is realised that departmental ultrasound is not cheap, there is also an economic benefit with applicability within both inpatient and outpatient clinic settings. While acknowledging its technical limits, pocket ultrasound devices may nevertheless be helpful in targeted situations for triage or for bedside follow-up exams after earlier high-end ultrasound-based diagnosis.

Radiologic Approach for Skin US.

Radiologic Approach for Skin US.

Development of Preclinical Ultrasound Imaging Techniques to Identify and Image Sentinel Lymph Nodes in a Cancerous Animal Model.

Simple SummaryBowel cancer is the fourth most common cancer in the UK. Treatment is dominated by major surgery because current imaging modalities cannot accurately determine lymph node involvement or vascular invasion. Although potentially curative, surgery carries a high risk of short- and long-term morbidity, including stoma formation. Optimized pre-treatment imaging would decrease the number of bowel cancer patients requiring major surgery. Such imaging would also be equally applicable to other cancers where local resection could significantly improve patient quality of life without compromising long-term outcomes (e.g., melanoma, head and neck cancers, gastro-esophageal, bladder). In this study, we created two mouse models (tumor and control) and used the resolution of high-frequency ultrasound imaging and parameters calculated from dynamically contrast-enhanced ultrasound to predict the likelihood of draining lymph nodes to be involved in the disease.Lymph nodes (LNs) are believed to be the first organs targeted by colorectal cancer cells detached from a primary solid tumor because of their role in draining interstitial fluids. Better detection and assessment of these organs have the potential to help clinicians in stratification and designing optimal design of oncological treatments for each patient. Whilst highly valuable for the detection of primary tumors, CT and MRI remain limited for the characterization of LNs. B-mode ultrasound (US) and contrast-enhanced ultrasound (CEUS) can improve the detection of LNs and could provide critical complementary information to MRI and CT scans; however, the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) guidelines advise that further evidence is required before US or CEUS can be recommended for clinical use. Moreover, knowledge of the lymphatic system and LNs is relatively limited, especially in preclinical models. In this pilot study, we have created a mouse model of metastatic cancer and utilized 3D high-frequency ultrasound to assess the volume, shape, and absence of hilum, along with CEUS to assess the flow dynamics of tumor-free and tumor-bearing LNs in vivo. The aforementioned parameters were used to create a scoring system to predict the likelihood of a disease-involved LN before establishing post-mortem diagnosis with histopathology. Preliminary results suggest that a sum score of parameters may provide a more accurate diagnosis than the LN size, the single parameter currently used to predict the involvement of an LN in disease.

Standardized contrast-enhanced ultrasound (CEUS) in clinical acute and emergency medicine and critical care (CEUS Acute) : Consensus statement of DGIIN, DIVI, DGINA, DGAI, DGK, ÖGUM, SGUM and DEGUM

The present document describes the possible applications of contrast-enhanced ultrasound (CEUS) in emergency examinations. Guidelines on contrast medium ultrasound in acute and emergency care and intensive care medicine have not yet been published. Evidence-based CEUS guidelines were first provided by the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) and the World Federation for Ultrasound in Medicine and Biology (WFUMB). The presented recommendations describe the possible applications and protocols of CEUS in acute care.

Head and Neck Ultrasound - EFSUMB Training Recommendations for the Practice of Medical Ultrasound in Europe.

Different surgical and medical specialists increasingly use head and neck ultrasound and ultrasound-guided interventions as part of their clinical practice. We need to ensure high quality and standardized practice across specialties, and this position paper of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) describes the training requirements for head and neck ultrasound. Traditionally, a minimum number of ultrasound examinations indicates competence, but this is unreliable, and a general shift towards competence-based training is ongoing. For each EFSUMB level, we will outline the theoretical knowledge and skills needed for clinical practice. The recommendations follow the three EFSUMB competency levels for medical ultrasound practice. Level 1 describes the skills required to perform essential head and neck ultrasound examinations independently, level 2 includes ultrasound-guided interventions, while level 3 involves the practice of high-level neck ultrasound and use of advanced technologies. Our goal is to ensure high quality and standardized head and neck ultrasound practice performed by different clinical specialists with these recommendations.

EFSUMB 50th years anniversary: a call for participation and support

February 11, 2022, marks the 50th anniversary of the founding of European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB). Our next EUROSON Congress from 25–28 May 2022 in Timisoara, jointly organised with World Federation of Ultrasound in Medicine and Biology (WFUMB) and the Romanian Ultrasound Society, will provide the opportunity to celebrate the 50 years success story of the European Ultrasound Family. Reflecting on our own roots can open the horizons to how today’s problems can be more easily overcome. Pride in the achievements of ultrasound pioneers, organizers of milestone congresses of EFSUMB and its national member societies, and the developers of new ultrasound technologies should stimulate us to develop new ideas for the future of ultrasound.

The EFSUMB Guidelines and Recommendations for Musculoskeletal Ultrasound - Part I: Extraarticular Pathologies.

The first part of the guidelines and recommendations for musculoskeletal ultrasound, produced under the auspices of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB), provides information about the use of musculoskeletal ultrasound for assessing extraarticular structures (muscles, tendons, entheses, ligaments, bones, bursae, fasciae, nerves, skin, subcutaneous tissues, and nails) and their pathologies. Clinical applications, practical points, limitations, and artifacts are described and discussed for every structure. After an extensive literature review, the recommendations have been developed according to the Oxford Centre for Evidence-based Medicine and GRADE criteria and the consensus level was established through a Delphi process. The document is intended to guide clinical users in their daily practice.

Gastrointestinal Ultrasound in Functional Disorders of the Gastrointestinal Tract - EFSUMB Consensus Statement.

Abdominal ultrasonography and intestinal ultrasonography are widely used as first diagnostic tools for investigating patients with abdominal symptoms, mainly for excluding organic diseases. However, gastrointestinal ultrasound (GIUS), as a real-time diagnostic imaging method, can also provide information on motility, flow, perfusion, peristalsis, and organ filling and emptying, with high temporal and spatial resolution. Thanks to its noninvasiveness and high repeatability, GIUS can investigate functional gastrointestinal processes and functional gastrointestinal diseases (FGID) by studying their behavior over time and their response to therapy and providing insight into their pathophysiologic mechanisms. The European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) has established a Task Force Group consisting of GIUS experts, which developed clinical recommendations and guidelines on the role of GIUS in several acute and chronic gastrointestinal diseases. This review is dedicated to the role of GIUS in assisting the diagnosis of FGID and particularly in investigating patients with symptoms of functional disorders, such as dysphagia, reflux disorders, dyspepsia, abdominal pain, bloating, and altered bowel habits. The available scientific evidence of GIUS in detecting, assessing, and investigating FGID are reported here, while highlighting sonographic findings and its usefulness in a clinical setting, defining the actual and potential role of GIUS in the management of patients, and providing information regarding future applications and research.

Prevalence of negative sliding sign representing pouch of Douglas obliteration during pelvic transvaginal ultrasound for any indication

Pouch of Douglas (POD) obliteration can be predicted with a high degree of certainty and reproducibility using the dynamic transvaginal ultrasound (TVS) sliding-sign technique. So far, studies on POD obliteration prediction have focused on tertiary-care populations with high prevalence of endometriosis; however, POD obliteration may exist in individuals with asymptomatic endometriosis or other conditions. Our primary aim was to determine the prevalence of a negative sliding sign, representing POD obliteration, in a cohort of patients undergoing TVS for any gynecological indication. This was a prospective observational study of consecutive women with an indication for gynecological TVS, conducted at a high-volume ultrasound practice between July and August 2018. Clinical and surgical history, indication for TVS and TVS findings were documented. The prevalence of TVS-confirmed POD obliteration, determined by interpretation of the sliding sign, was calculated for the entire cohort and for the subgroups of women with and without risk factors for endometriosis. High risk for endometriosis was defined as having (1) a TVS referral for endometriosis-like pelvic pain or endometriosis specifically and/or (2) clinical symptoms or signs suggestive of endometriosis. Low risk was defined as the absence of these characteristics. During the study period, 1043 consecutive women underwent TVS. After excluding those who underwent transabdominal ultrasound, had a history of hysterectomy or with missing data, 909 women were analyzed. The prevalence of a negative sliding sign in the entire cohort was 47/909 (5.2%). A negative sliding sign was observed in 22/639 (3.4%) women with a low risk for endometriosis and 25/243 (10.3%) of those with a high risk for endometriosis (difference in proportions, 6.9% (95% CI 2.8-10.9%); P < 0.001). We have demonstrated an overall prevalence of a negative sliding sign, suggesting POD obliteration, of 5.2% (or 1/20) in women seeking TVS for a gynecological indication. The prevalence of negative sliding sign in low-risk women is not negligible (3.4% or 1/29 women). These women are most likely to have asymptomatic endometriosis or another important etiology of POD obliteration. The prevalence of a negative sliding sign is approximately three-times higher in women with signs and/or symptoms of endometriosis (10.3% vs 3.4%). Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Guidelines and Good Clinical Practice Recommendations for Contrast Enhanced Ultrasound (CEUS) in the Liver - Update 2020 - WFUMB in Cooperation with EFSUMB, AFSUMB, AIUM, and FLAUS.

The present, updated document describes the fourth iteration of recommendations for the hepatic use of contrast enhanced ultrasound (CEUS), first initiated in 2004 by the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB). The previous updated editions of the guidelines reflected changes in the available contrast agents and updated the guidelines not only for hepatic but also for non-hepatic applications.The 2012 guideline requires updating as previously the differences of the contrast agents were not precisely described and the differences in contrast phases as well as handling were not clearly indicated. In addition, more evidence has been published for all contrast agents. The update also reflects the most recent developments in contrast agents, including the United States Food and Drug Administration (FDA) approval as well as the extensive Asian experience, to produce a truly international perspective.These guidelines and recommendations provide general advice on the use of ultrasound contrast agents (UCA) and are intended to create standard protocols for the use and administration of UCA in liver applications on an international basis to improve the management of patients.

Ultrasound Curricula of Student Education in Europe: Summary of the Experience.

Background Despite the increasing role of ultrasound, structured ultrasound teaching is only slowly being integrated into the curricula of medical schools and universities all over Europe. Aim To survey the current situation at European universities regarding the integration of ultrasound in student medical education and to report on models of student ultrasound training from selected European universities. Methods A questionnaire survey focusing on the implementation of curricular ultrasound education was sent out to the 28 presidents of the national ultrasound societies of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB), who were asked to distribute the questionnaires to the medical universities of their countries. Results Overall, 53 questionnaires were returned from 46 universities in 17 European countries. In most of the universities (40/46 universities, 87%), the theoretical background of ultrasound is taught. However, in only a minority of universities is ultrasound integrated in anatomy courses (8/46 universities, 17%) or basic science courses (16/46 universities, 35%). Practical skills in ultrasound are taught in 56% of the universities (26/46 universities) and tested in a practical exam in seven of the responding universities (15%). The number of hours in which ultrasound was taught ranged from one to 58 (mean, seven). The respondents reported that lack of time and limited faculty funding were major hurdles. Conclusion According to our survey, only a minority of European universities has integrated ultrasound into the preclinical curriculum thus far. Future EFSUMB initiatives will continue to promote the introduction of ultrasound as an integrative part of the core curriculum of student medical education, and the preparation of proper teaching material.

European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) Position Statement on Dermatologic Ultrasound.

Dermatologic ultrasound is a recent application of ultrasound for the evaluation of healthy skin and appendages and their diseases. Although the scientific literature regarding this application is still not sufficient for evidence-based guidelines, general recommendations issued by scientific societies are necessary. The EFSUMB (European Federation of Societies for Ultrasound in Medicine and Biology) steering committee for dermatologic ultrasound has developed a series of consensus position statements regarding the main fields of dermatologic ultrasound (technical requirement, normal skin and appendages, inflammatory skin diseases, tumoral skin diseases, aesthetic dermatology and practice-training requirements). This document is the foundation for future evidence-based recommendations and guidelines for dermatologic ultrasound practice.

Imaging Features of Fibrolamellar Hepatocellular Carcinoma withContrast-Enhanced Ultrasound.

Fibrolamellar hepatocellular carcinoma (f-HCC) is a rare primary liver tumor. Imaging plays an important role in diagnosis. The aim of this retrospective study was to analyze contrast-enhanced ultrasound (CEUS) features of histologically proven f-HCC in comparison to benign focal nodular hyperplasia (FNH). 16 patients with histologically proven f-HCC lesions and 30 patients with FNH lesions were retrospectively reviewed regarding CEUS features to determine the malignant or benign nature of the focal liver lesions (FLL). Five radiologists assessed the CEUS enhancement pattern and came to a consensus using the EFSUMB (European Federation of Societies for Ultrasound in Medicine and Biology) guideline criteria. Fibrolamellar hepatocellular carcinoma manifested as a single and huge FLL. On CEUS, f-HCC showed heterogeneous hyperenhancement in the arterial phase and hypoenhancement (16/16, 100 %) in the portal venous and late phases (PVLP) as a sign of malignancy. In contrast to the hypoenhancement of f-HCC in the PVLP, all patients with FNH showed hyperenhancement as the most distinctive feature (P < 0.01). 8 f-HCC lesions showed a central scar as an unenhanced area (8/16, 50.0 %), which could also be detected in 53.3 % (16/30) of FNH lesions (P > 0.05). By analyzing the hypoenhancement in the PVLP, CEUS imaging reliably diagnosed f-HCC as a malignant FLL. CEUS also showed differentiation between f-HCC and FNH lesions, showing similar non-enhanced central scars, whereas f-HCC lesions showed peripheral hyperenhancement in the arterial phase and early washout in the PVLP.