Clinical management, pathogen spectrum and outcomes in patients with pyogenic liver abscess in a German tertiary-care hospital.

Pyogenic liver abscesses (PLA) are life-threatening disorders and require immediate treatment, but structured evidence is sparse and treatment guidelines are not established. In a retrospective observational study of 221 adult PLA patients (mean age 63 years, 63% men) treated between 2013 and 2019 at the Leipzig University Medical Center, we characterized pathogen spectrum, clinical management and outcomes. Biliary malignancies (33%), cholelithiasis (23%) and ischemic biliary tract disease (16%) were most common causes of PLA. Comorbidities included malignancies (40%) and diabetes mellitus (35%). Abdominal ultrasound was the preferred initial imaging modality (58%). Enterobacterales (58%), enterococci (42%) and streptococci (18%) were identified as most frequent pathogens. 97% of patients were treated with antibiotics and 75% of patients underwent an invasive treatment procedure. The 30-day mortality was almost identical in patients with and without underlying malignancy (14.6% vs. 14.4%, p = 0.96), while the one-year outcome differed significantly (58.4% vs. 29.6%, p < 0.001). Positive blood cultures (OR 4.78, 95% CI 1.39 to 22.5, p = 0.023) and detection of Enterobacterales (OR 3.55, 95% CI 1.40 to 9.97, p = 0.010) were associated with increased 30-day-mortality. We conclude that ultrasound, extensive microbiologic diagnosis, adequate anti-infective therapy and early intervention are crucial for the management of PLA.

Thy-1 restricts steatosis and liver fibrosis in steatotic liver disease.

BACKGROUND AND AIMS: Steatotic liver disease (SLD) is generally considered to represent a hepatic manifestation of metabolic syndrome and includes a disease spectrum comprising isolated steatosis, metabolic dysfunction-associated steatohepatitis, liver fibrosis and ultimately cirrhosis. A better understanding of the detailed underlying pathogenic mechanisms of this transition is crucial for the design of new and efficient therapeutic interventions. Thymocyte differentiation antigen (Thy-1, also known as CD90) expression on fibroblasts controls central functions relevant to fibrogenesis, including proliferation, apoptosis, cytokine responsiveness, and myofibroblast differentiation. METHODS: The impact of Thy-1 on the development of SLD and progression to fibrosis was investigated in high-fat diet (HFD)-induced SLD wild-type and Thy-1-deficient mice. In addition, the serum soluble Thy-1 (sThy-1) concentration was analysed in patients with metabolic dysfunction-associated SLD stratified according to steatosis, inflammation, or liver fibrosis using noninvasive markers. RESULTS: We demonstrated that Thy-1 attenuates the development of fatty liver and the expression of profibrogenic genes in the livers of HFD-induced SLD mice. Mechanistically, Thy-1 directly inhibits the profibrotic activation of nonparenchymal liver cells. In addition, Thy-1 prevents palmitic acid-mediated amplification of the inflammatory response of myeloid cells, which might indirectly contribute to the pronounced development of liver fibrosis in Thy-1-deficient mice. Serum analysis of patients with metabolically associated steatotic liver disease syndrome revealed that sThy-1 expression is correlated with liver fibrosis status, as assessed by liver stiffness, the Fib4 score, and the NAFLD fibrosis score. CONCLUSION: Our data strongly suggest that Thy-1 may function as a fibrosis-protective factor in mouse and human SLD.

Ultrasound-guided percutaneous biopsy for focal liver lesions: Adverse events and diagnostic yield in a single-centre analysis.

PURPOSE: Ultrasound-guided biopsy of focal liver lesions (FLL) is a well-established procedure with crucial impact on therapeutic decisions. The safety and accuracy depend on needle type, tumour location and comorbidities. Modern oncological concepts often require large tumour specimens which may increase the procedural risk. MATERIALS AND METHODS: We retrospectively collected data from consecutively scheduled ultrasound-guided FLL biopsies performed in an interdisciplinary ultrasound unit at a university hospital from 2015-2020. We analysed complication rates, diagnostic accuracy, and patient outcome in a one-year period. RESULTS: Of 426 scheduled interventions, 339 were included: 322 primary biopsies (40% female, median age 65 years, median BMI 25.4 kg/m2) and 17 rebiopsies in cases with undetermined diagnosis. Indications comprised 309 (96%) cases with suspected malignant lesions. Important comorbidities were type 2 diabetes (n = 107, 33%) and cirrhosis (n = 64, 20%). A conclusive histopathological diagnosis was achieved in 270 (84%) cases with a weak association with lesion size (OR 1.12 per cm, 95%CI 0.99-1.27). Greater BMI (OR 0.60 per 10 BMI points, 95%CI 0.34-1.05) showed a trend towards an insufficient diagnosis. Relevant complications occurred in 8 (2.5%) cases (2 major; 1 life-threatening). Multiple passes showed a trend towards adverse events (OR 2.32 for > 1 pass, 95%CI 0.99-5.42). 93 (29%) patients died during a median follow-up of 171 days. CONCLUSION: Ultrasound-guided FLL biopsy is an efficient and safe diagnostic measure. The limitations of the procedure and its associated risks should be considered in patients with advanced malignancies.

WFUMB Guideline/Guidance on Liver Multiparametric Ultrasound: Part 1. Update to 2018 Guidelines on Liver Ultrasound Elastography.

The World Federation for Ultrasound in Medicine and Biology (WFUMB) endorsed the development of this document on multiparametric ultrasound. Part 1 is an update to the WFUMB Liver Elastography Guidelines Update released in 2018 and provides new evidence on the role of ultrasound elastography in chronic liver disease. The recommendations in this update were made and graded using the Oxford classification, including level of evidence (LoE), grade of recommendation (GoR) and proportion of agreement (Oxford Centre for Evidence-Based Medicine [OCEBM] 2009). The guidelines are clinically oriented, and the role of shear wave elastography in both fibrosis staging and prognostication in different etiologies of liver disease is discussed, highlighting advantages and limitations. A comprehensive section is devoted to the assessment of portal hypertension, with specific recommendations for the interpretation of liver and spleen stiffness measurements in this setting.

Diagnostic accuracy of non-invasive tests to screen for at-risk MASH-An individual participant data meta-analysis.

BACKGROUND & AIMS: There is a need to reduce the screen failure rate (SFR) in metabolic dysfunction-associated steatohepatitis (MASH) clinical trials (MASH+F2-3; MASH+F4) and identify people with high-risk MASH (MASH+F2-4) in clinical practice. We aimed to evaluate non-invasive tests (NITs) screening approaches for these target conditions. METHODS: This was an individual participant data meta-analysis for the performance of NITs against liver biopsy for MASH+F2-4, MASH+F2-3 and MASH+F4. Index tests were the FibroScan-AST (FAST) score, liver stiffness measured using vibration-controlled transient elastography (LSM-VCTE), the fibrosis-4 score (FIB-4) and the NAFLD fibrosis score (NFS). Area under the receiver operating characteristics curve (AUROC) and thresholds including those that achieved 34% SFR were reported. RESULTS: We included 2281 unique cases. The prevalence of MASH+F2-4, MASH+F2-3 and MASH+F4 was 31%, 24% and 7%, respectively. Area under the receiver operating characteristics curves for MASH+F2-4 were .78, .75, .68 and .57 for FAST, LSM-VCTE, FIB-4 and NFS. Area under the receiver operating characteristics curves for MASH+F2-3 were .73, .67, .60, .58 for FAST, LSM-VCTE, FIB-4 and NFS. Area under the receiver operating characteristics curves for MASH+F4 were .79, .84, .81, .76 for FAST, LSM-VCTE, FIB-4 and NFS. The sequential combination of FIB-4 and LSM-VCTE for the detection of MASH+F2-3 with threshold of .7 and 3.48, and 5.9 and 20 kPa achieved SFR of 67% and sensitivity of 60%, detecting 15 true positive cases from a theoretical group of 100 participants at the prevalence of 24%. CONCLUSIONS: Sequential combinations of NITs do not compromise diagnostic performance and may reduce resource utilisation through the need of fewer LSM-VCTE examinations.

WFUMB Guidelines/Guidance on Liver Multiparametric Ultrasound. Part 2: Guidance on Liver Fat Quantification.

The World Federation for Ultrasound in Medicine and Biology (WFUMB) has promoted the development of this document on multiparametric ultrasound. Part 2 is a guidance on the use of the available tools for the quantification of liver fat content with ultrasound. These are attenuation coefficient, backscatter coefficient, and speed of sound. All of them use the raw data of the ultrasound beam to estimate liver fat content. This guidance has the aim of helping the reader in understanding how they work and interpret the results. Confounding factors are discussed and a standardized protocol for measurement acquisition is suggested to mitigate them. The recommendations were based on published studies and experts' opinion but were not formally graded because the body of evidence remained low at the time of drafting this document.

Student ultrasound education - current views and controversies.

As an extension of the clinical examination and as a diagnostic and problem-solving tool, ultrasound has become an established technique for clinicians. A prerequisite for high-quality clinical ultrasound practice is adequate student ultrasound training. In light of the considerable heterogeneity of ultrasound curricula in medical studies worldwide, this review presents basic principles of modern medical student ultrasound education and advocates for the establishment of an ultrasound core curriculum embedded both horizontally and vertically in medical studies.

Development, evaluation, and overview of standardized training phantoms for abdominal ultrasound-guided interventions.

PURPOSE: Ultrasound (US) represents the primary approach for abdominal diagnosis and is regularly used to guide diagnostic and therapeutic interventions (INVUS). Due to possible serious INVUS complications, structured training concepts are required. Phantoms can facilitate teaching, but their use is currently restricted by complex manufacturing and short durability of the materials. Hence, the aim of this study was the development and evaluation of an optimized abdominal INVUS phantom. MATERIALS AND METHODS: Phantom requirements were defined in a structured research process: Skin-like surface texture, homogeneous matrix with realistic tissue properties, implementation of lesions and abscess cavities in different sizes and depths as well as a modular production process allowing for customized layouts. The phantom prototypes were evaluated in certified ultrasound courses. RESULTS: In accordance with the defined specifications, a new type of matrix was developed and cast in multiple layers including different target materials. The phantom structure is based on features of liver anatomy and includes solid focal lesions, vessels, and abscess formations. For a realistic biopsy procedure, ultrasound-proof material was additionally included to imitate bone. The evaluation was performed by US novices (n=40) and experienced participants (n=41). The majority (73/81) confirmed realistic visualization of the lesions. The 3D impression was rated as "very good" in 64% of cases (52/81) and good in 31% (25/81). Overall, 86% (70/81) of the participants certified high clinical relevance of the phantom. CONCLUSION: The presented INVUS phantom concept allows standardized and realistic training for interventions.

[State of the art: Simulation in US]. / State of the art: Simulation in der Ultraschallausbildung.

Technical simulation of diagnostic and therapeutic procedures is of growing relevance for student education and advanced medical training and has already been introduced in the field of ultrasound. This review gives a broad overview on different levels of simulation for ultrasound diagnostics and highlights the technical background of the methodology. A critical review of the literature reveals recommendations for implementing simulation techniques in medical studies and professional ultrasound training. An analysis of strengths and weaknesses shows the advantages of simulation especially in the context of individual learning situations and COVID-19-related restrictions for personal interaction. However, simulation techniques cannot replace the experiences of complex clinical examinations with direct interaction to real patients. Therefore, future applications may focus on repetition and assessment of achieved competencies by using standardized feedback mechanisms in order to preserve the limited resources for practical medical training.

Relevance of GLP-1 receptor agonists or SGLT-2 inhibitors on the recruitment for clinical studies in patients with NAFLD.

INTRODUCTION: Guidelines increasingly recommend the use of glucagon-like peptide-1 receptor agonists (GLP-1 RA) or sodium-glucose co-transporter-2 inhibitors (SGLT2i) to prevent cardiovascular and cardiorenal endpoints. Both drugs also show beneficial effects in nonalcoholic fatty liver disease (NAFLD). Preexisting GLP-1 RA and SGLT2i therapies are frequently defined as exclusion criterion in clinical studies to avoid confounding effects. We therefore investigated how this might limit recruitment and design of NAFLD studies. METHODS: GLP-1 RA and SGLT2i prescriptions were analyzed in NAFLD patients with diabetes mellitus recruited at a tertiary referral center and from the population-based LIFE-Adult-Study. Individuals were stratified according to noninvasive parameters of liver fibrosis based on vibration-controlled transient elastography (VCTE). RESULTS: 97 individuals were recruited at tertiary care and 473 from the LIFE-Adult-Study. VCTE was available in 97/97 and 147/473 cases.GLP-1 RA or SGLT2i were used in 11.9% of the population-based cohort (LSM < 8 kPa), but in 32.0% with LSM ≥ 8 kPa. In the tertiary clinic, it was 30.9% overall, independent of LSM, and 36.8% in patients with medium and high risk for fibrotic NASH (FAST score > 0.35). At baseline, 3.1% of the patients in tertiary care were taking GLP-1 RA and 4.1% SGLT2i. Four years later, the numbers had increased to 15.5% and 21.6%. CONCLUSION: GLP-1 RA and SGLT2i are frequently and increasingly prescribed. In candidates for liver biopsy for NASH studies (VCTE ≥ 8 kPa) the use of them exceeds 30%, which needs careful consideration when designing NASH trials.

Non-invasive assessment of steatohepatitis indicates increased risk of coronary artery disease.

INTRODUCTION: Fatty liver diseases (FLD), especially defined as metabolic dysfunction-associated FLD (MAFLD), is of growing importance for patients and health-care providers. Extrahepatic comorbidities, predominantly coronary artery disease (CAD), contribute to excess morbidity and mortality in FLD. Although the association of FLD and CAD is well known, underlying pathophysiological links are not fully understood. Non-invasive means of liver diagnostic enable a fast and thorough characterization of FLD. We therefore assessed the severity of FLD in a cohort of patients at risk of CAD. METHODS: Patients scheduled for coronary angiography were characterized by anthropometry, serum-based indices of liver fibrosis (NFS, FIB4), abdominal ultrasound and vibration controlled transient elastography (VCTE) including controlled attenuation parameter (CAP) and the Fibroscan-AST (FAST) score. Patients were stratified according to indication of therapeutic coronary intervention. RESULTS: 120 patients were recruited, MAFLD was found in 41%, while advanced fibrosis or cirrhosis were present in only 5%. Coronary vascular intervention was indicated in 42% (n = 50). Severity of steatosis assessed by CAP and risk of fibrosis defined by elevated liver stiffness (VCTE>8 kPa) and fibrosis indices were associated with the need for coronary intervention. FAST score, a marker of fibrotic steatohepatitis, was elevated in the intervention group (0.22 vs. 0.12, p<0.001). Multivariate regression analysis revealed FAST score as strongest predictor of CAD (OR 2.3 95%, CI 1.40-2.96). DISCUSSION: MAFLD is a frequent comorbidity in patients at CAD risk, but advanced liver disease has a low prevalence in patients undergoing elective coronary angiography. Therefore, a routine VCTE-based screening for FLD cannot be recommended in cardiac patients. The association of indicators of steatohepatitis with advanced CAD points to inflammatory processes as a conjoint mechanism of both diseases.

The application of high-performance ultrasound probes increases anatomic depiction in obese patients.

This study evaluated the impact of obesity on abdominal ultrasound diagnostics and assessed effect of high-performance ultrasound probes increased imaging quality. Lean and obese subjects (n = 40; 58% female) were categorized according to body mass index (BMI, 21 to 48 kg/m2). A highly standardized ultrasound examination of the abdomen was performed by trained examiners using three different probes in randomized order (standard probe versus two high-performance probes). Quality of B-mode and duplex ultrasound were assessed using a custom scoring approach for depiction of liver and kidney anatomy and vascularization. Across probes, imaging quality of hepatic and kidney anatomy was inversely related with BMI (P < 0.03, r < - 0.35). Age, sex, and BMI explained 51% of the variance within the ultrasound quality score, with ß = - 0.35, P < 0.0001 for BMI. Compared to the standard probe, high-performance probes allowed for a better depiction of kidney and liver anatomy in subjects above BMI 35 kg/m2 (n = 20, all P < 0.05), resulting in a less pronounced deterioration of imaging quality with increased BMI (all P < 0.05). In conclusion the study shows that obesity impairs ultrasound imaging quality of abdominal anatomy. The application of high-performance probes can increase anatomic depiction in obese patients.Registration number of the German Registry of Clinical Studies: DRKS00023498.

Performance of non-invasive tests and histology for the prediction of clinical outcomes in patients with non-alcoholic fatty liver disease: an individual participant data meta-analysis.

BACKGROUND: Histologically assessed liver fibrosis stage has prognostic significance in patients with non-alcoholic fatty liver disease (NAFLD) and is accepted as a surrogate endpoint in clinical trials for non-cirrhotic NAFLD. Our aim was to compare the prognostic performance of non-invasive tests with liver histology in patients with NAFLD. METHODS: This was an individual participant data meta-analysis of the prognostic performance of histologically assessed fibrosis stage (F0-4), liver stiffness measured by vibration-controlled transient elastography (LSM-VCTE), fibrosis-4 index (FIB-4), and NAFLD fibrosis score (NFS) in patients with NAFLD. The literature was searched for a previously published systematic review on the diagnostic accuracy of imaging and simple non-invasive tests and updated to Jan 12, 2022 for this study. Studies were identified through PubMed/MEDLINE, EMBASE, and CENTRAL, and authors were contacted for individual participant data, including outcome data, with a minimum of 12 months of follow-up. The primary outcome was a composite endpoint of all-cause mortality, hepatocellular carcinoma, liver transplantation, or cirrhosis complications (ie, ascites, variceal bleeding, hepatic encephalopathy, or progression to a MELD score ≥15). We calculated aggregated survival curves for trichotomised groups and compared them using stratified log-rank tests (histology: F0-2 vs F3 vs F4; LSM: <10 vs 10 to <20 vs ≥20 kPa; FIB-4: <1·3 vs 1·3 to ≤2·67 vs >2·67; NFS: <-1·455 vs -1·455 to ≤0·676 vs >0·676), calculated areas under the time-dependent receiver operating characteristic curves (tAUC), and performed Cox proportional-hazards regression to adjust for confounding. This study was registered with PROSPERO, CRD42022312226. FINDINGS: Of 65 eligible studies, we included data on 2518 patients with biopsy-proven NAFLD from 25 studies (1126 [44·7%] were female, median age was 54 years [IQR 44-63), and 1161 [46·1%] had type 2 diabetes). After a median follow-up of 57 months [IQR 33-91], the composite endpoint was observed in 145 (5·8%) patients. Stratified log-rank tests showed significant differences between the trichotomised patient groups (p<0·0001 for all comparisons). The tAUC at 5 years were 0·72 (95% CI 0·62-0·81) for histology, 0·76 (0·70-0·83) for LSM-VCTE, 0·74 (0·64-0·82) for FIB-4, and 0·70 (0·63-0·80) for NFS. All index tests were significant predictors of the primary outcome after adjustment for confounders in the Cox regression. INTERPRETATION: Simple non-invasive tests performed as well as histologically assessed fibrosis in predicting clinical outcomes in patients with NAFLD and could be considered as alternatives to liver biopsy in some cases. FUNDING: Innovative Medicines Initiative 2.

Quantification of Portal Vein Vascularization Using an Automated Post-Processing Video Analysis Tool.

Purpose Blood flow dynamics represent a diagnostic criterion for many diseases. However, no established reference standard is available. In clinical practice, ultrasound pulsed-wave Doppler (PW-Doppler) is frequently used to assess visceral blood flow, despite its well-known limitations. A quantitative analysis of conventional color Doppler patterns can be performed using an innovative ultrasound-based algorithm (pixel flow analysis, PFA). This tool already shows promising results in obstetrics, but the technique has not yet been evaluated for portal venous blood flow assessment. Methods This prospective exploratory research study evaluated the applicability of PFA in the portal venous system. Measurements of portal venous flow using PFA and PW-Doppler were compared in healthy volunteers (n=20) and in patients with hepatic steatosis (n=10) and liver cirrhosis (n=10). Results In healthy volunteers (60% female, mean age 23 years, BMI 21.5 kg/m 2 [20.4-23.8]), PFA and PW-Doppler showed a strong positive correlation in fasting conditions (r=0.69; 95% CI 0.36-0.87), recording a median blood flow of 834 ml/min (624-1066) and 718 ml/min (620-811), respectively. PFA was also applicable in patients with chronic liver diseases (55% female, age 65 years (55-72); BMI 27.8 kg/m 2 (25.4-30.8)), but the correlation between PFA and PW-Doppler was poor (r=- 0.09) in the subgroup with steatosis. A better correlation (r=0.61) was observed in patients with liver cirrhosis. Conclusion PFA and PW-Doppler assessment of portal venous vascularization showed high agreement in healthy volunteers and patients with liver cirrhosis. Therefore, PFA represents a possible alternative to conventional PW-Doppler sonography for visceral blood flow diagnostics and merits further evaluation.

Noninvasive assessment of liver disease severity in patients with nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes.

BACKGROUND AND AIMS: We evaluated the diagnostic accuracy of simple, noninvasive tests (NITs) in NAFLD patients with type 2 diabetes (T2D). METHODS AND RESULTS: This was an individual patient data meta-analysis of 1780 patients with biopsy-proven NAFLD and T2D. The index tests of interest were FIB-4, NAFLD Fibrosis Score (NFS), aspartate aminotransferase-to-platelet ratio index, liver stiffness measurement (LSM) by vibration-controlled transient elastography, and AGILE 3+. The target conditions were advanced fibrosis, NASH, and fibrotic NASH(NASH plus F2-F4 fibrosis). The diagnostic performance of noninvasive tests. individually or in sequential combination, was assessed by area under the receiver operating characteristic curve and by decision curve analysis. Comparison with 2278 NAFLD patients without T2D was also made. In NAFLD with T2D LSM and AGILE 3+ outperformed, both NFS and FIB-4 for advanced fibrosis (area under the receiver operating characteristic curve:LSM 0.82, AGILE 3+ 0.82, NFS 0.72, FIB-4 0.75, aspartate aminotransferase-to-platelet ratio index 0.68; p < 0.001 of LSM-based versus simple serum tests), with an uncertainty area of 12%-20%. The combination of serum-based with LSM-based tests for advanced fibrosis led to a reduction of 40%-60% in necessary LSM tests. Decision curve analysis showed that all scores had a modest net benefit for ruling out advanced fibrosis at the risk threshold of 5%-10% of missing advanced fibrosis. LSM and AGILE 3+ outperformed both NFS and FIB-4 for fibrotic NASH (area under the receiver operating characteristic curve:LSM 0.79, AGILE 3+ 0.77, NFS 0.71, FIB-4 0.71; p < 0.001 of LSM-based versus simple serum tests). All noninvasive scores were suboptimal for diagnosing NASH. CONCLUSIONS: LSM and AGILE 3+ individually or in low availability settings in sequential combination after FIB-4 or NFS have a similar good diagnostic accuracy for advanced fibrosis and an acceptable diagnostic accuracy for fibrotic NASH in NAFLD patients with T2D.

[Ultrasound systems for abdominal diagnostics - current methods, clinical applications and new technologies]. / Ultraschallgeräte für die abdominelle Diagnostik: neue Techniken und Applikationen ­ Was gibt es? Was ist möglich? Was ist sinnvoll?

Abdominal ultrasound is the method of first choice in many clinical situations. Gray scale imaging (B-mode) and conventional Doppler techniques are nowadays complemented by contrast-enhanced ultrasound (CEUS), elastography, fat quantification and further technologies which allow multimodal characterization of organs and tissue structure using panoramic imaging, 3D-techniques and image fusion. The development of small portable devices augments the spectrum for sonographic diagnostics. In this review, we describe the current status of ultrasound technology based on published evidence. In addition, we provide guidance for quality assurance.