Hepatocellular carcinoma (HCC) requires nuanced treatment response assessment to balance oncologic control with preservation of liver function. CT and MRI, cornerstones of response evaluation, are often limited by contraindications to their use or indeterminate findings. The recently introduced ACR LI-RADS Contrast-Enhanced Ultrasound (CEUS) Non-Radiation Treatment Response Assessment (TRA) algorithm offers a real-time, radiation-free alternative for evaluating treated HCC after ablation, transarterial therapies, or surgical resection. This review summarizes the CEUS TRA lexicon, criteria, and application across common clinical scenarios, emphasizing its value as a troubleshooting tool when conventional imaging is non-evaluable due to artifacts, contrast limitations, or heterogeneous post-treatment changes. We highlight pitfalls unique to CEUS interpretation, including poor lesion visibility, resection cavity complexity, and the inability to assess extrahepatic disease. Emerging areas include CEUS assessment after radiation-based therapies and the potential for integration of Kupffer-cell–specific contrast agents. Together, these developments position CEUS as an increasingly important modality for precise, timely, and individualized management of HCC following non-radiation locoregional therapy.

Metabolic dysfunction-associated steatotic liver disease is now the leading cause of chronic liver disease. Microvesicular steatosis is specifically associated with progression to cirrhosis, whereas macrovesicular steatosis is typically indolent. Current noninvasive tools for liver fat quantification fail to differentiate these forms of steatosis, limiting patient-tailored management. Quantitative ultrasound (QUS) is uniquely positioned overcome this limitation. The size and spatial distribution of lipid vacuoles is known to influence acoustic properties and, consequently, QUS-based liver fat measurements. However, no clinical studies or phantom models currently account for lipid microstructure, leaving the clinical potential of QUS unexplored. This work addresses this gap by developing novel, multimodal liver phantoms that replicate hepatic architecture, fat content, and the microstructural characteristics of microvesicular and macrovesicular steatosis. Phantom structure and composition were validated using microscopy and chemical analysis, and imaging performance was evaluated using ultrasound, magnetic resonance imaging, and computed tomography. These phantoms provide a robust platform for evaluating and standardizing QUS tools and for advancing noninvasive characterization of hepatic steatosis, with the potential to improve risk stratification and personalized disease management. [Work supported by the Society for Radiologists in Ultrasound, the Radiological Society of North America and the Siemens Partnership Grant.]

Despite growing clinical use of contrast-enhanced ultrasound (CEUS), inconsistency remains in the modality's role in clinical pathways for hepatocellular carcinoma (HCC) diagnosis and management. This AJR Expert Panel Narrative Review provides practical insights on the use of CEUS for the diagnosis of HCC across populations, including individuals at high risk for HCC, individuals with metabolic dysfunction-associated steatotic liver disease, and individuals not at high risk for HCC. Considerations addressed with respect to high-risk patients include CEUS diagnostic criteria for HCC, use of CEUS for differentiating HCC from non-HCC malignancy, use of CEUS for small (≤ 2 cm) lesions, use of CEUS for characterizing occult lesions on B-mode ultrasound, and use of CEUS for indeterminate lesions on CT or MRI. Representative literature addressing the use of CEUS for HCC diagnosis and gaps in knowledge requiring further investigation are highlighted. Throughout these discussions, the article distinguishes two broad types of ultrasound contrast agents used for liver imaging: pure blood-pool agents and a combined blood-pool and Kupffer-cell agent. Additional topics include the use of CEUS for treatment response assessment after nonradiation therapies and implications of artificial intelligence technologies. The article concludes with a series of consensus statements from the author panel.

Despite advances in ultrasound-based noninvasive hepatic steatosis quantification, current methods remain insensitive to the microstructural phenotype of lipid accumulation, which influences outcomes in metabolic dysfunction-associated steatotic liver disease. A methodology is introduced to generate tissue-mimicking phantom models that replicate the lobular liver histologic structure and pathologic patterns of steatosis. Phantoms consist of packed alginate capsules that mimic liver lobules and maintain continuous inter-capsule contact, embedded in agar. Lipid microparticles of controlled size and concentration are encapsulated within these capsules together with perfluorooctyl bromide microparticles serving as background scatterers. This architecture enables control of microscopic features (lipid vacuole size and density) and macroscopic organization (lobular-scale heterogeneity), both of which are expected to influence quantitative acoustic measurements, thereby more closely reproducing the histologic structure and acoustic behavior of healthy and diseased liver tissue. Phantoms with 0% and 20% fat (weight/volume) exhibit liver-like appearance on B-mode ultrasound imaging, with ultrasound-derived fat fraction and acoustic attenuation correlating with fat content. Chosen constituents enable compatibility with MRI and CT. This platform provides a structurally realistic model to refine and develop ultrasound liver fat quantification techniques and to support cross-vendor standardization, as well as cross-modality validation of ultrasound-based liver fat quantification using MRI and CT.

Contrast-enhanced US Liver Imaging Reporting and Data System (LI-RADS) could resolve some indeterminate liver observations (categorized as LR-4 and LR-M at CT or MRI), having a particularly high clinical effect for observations measuring at least 20 mm.

Metabolic dysfunction‐associated steatotic liver disease (MASLD) typically presents as “macrovesicular steatosis”, where each hepatocyte contains a large fat vacuole (30‐50 µm), indicating a more indolent form. In about 20% of cases, “microvesicular steatosis” occurs, with smaller vacuoles (1‐15 µm) linked to steatohepatitis, cirrhosis progression, and increased risk of liver cancer. Emerging quantitative ultrasound (QUS) liver fat quantification (QUS‐LFQ) tools measure various acoustic properties, but few methods compare techniques and imaging modalities, and the impact of fat vacuole size remains unclear. This study introduces a methodology to create ultrasound (US) phantoms that replicate fat vesicle size in MASLD. While imaging phantoms validate quantitative tools, no model currently links QUS‐LFQ measurements to steatosis severity. Existing homogeneous phantoms assessing properties like attenuation, backscatter, and speed of sound overlook the microstructure of steatosis, despite the known effect of particle size on acoustic interactions. Here, agar‐based phantoms simulate fat accumulation in steatotic hepatocytes using stable peanut oil droplets as analogs for lipid vacuoles. Microscopy and sizing confirm stability at 4 °C, 23 °C, and 50 °C. Both microscopy and US imaging confirm uniform distribution, with QUS‐LFQ measurements reflecting fat content. These phantoms hold promise for validating quantitative imaging methods, particularly for US‐based MASLD screening tools.

OBJECTIVE:Liver cancer ranks among the most lethal cancers. Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and better diagnostic tools are needed to diagnose patients at risk. The aim is to develop a machine learning algorithm that enhances the sensitivity and specificity of the Contrast-Enhanced Ultrasound Liver Imaging Reporting and Data System (CEUS-LIRADS) in classifying indeterminate at-risk liver nodules (LR-M, LR-3, LR-4) as HCC or non-HCC. METHODS:Our study includes patients at risk for HCC with untreated indeterminate focal liver observations detected on US or contrast-enhanced CT or MRI performed as part of their clinical standard of care from January 2018 to November 2022. Recursive partitioning was used to improve HCC diagnosis in indeterminate at-risk nodules. Demographics, blood biomarkers, and CEUS imaging features were evaluated as potential predictors for the algorithm to classify nodules as HCC or non-HCC. RESULTS:We evaluated 244 indeterminate liver nodules from 224 patients (mean age 62.9 y). Of the nodules, 73.2% (164/224) were from males. The algorithm was trained on a random 2/3 partition of 163 liver nodules and correctly reclassified more than half of the HCC liver nodules previously categorized as indeterminate in the independent 1/3 test partition of 81 liver nodules, achieving a sensitivity of 56.3% (95% CI: 42.0%, 70.2%) and specificity of 93.9% (95% CI: 84.4%, 100.0%). CONCLUSION:Machine learning was applied to the multicenter, multinational study of CEUS LI-RADS indeterminate at-risk liver nodules and correctly diagnosed HCC in more than half of the HCC nodules.

Ultrasound (US) has many known advantages, including lack of ionizing radiation, low operating cost, and an unmatched safety profile. The development of contrast-enhanced US (CEUS) has proven to be a useful alternative or adjunct in the assessment of multiple organ system pathology, including genitourinary (GU), gastrointestinal, and pulmonary applications. CEUS offers several advantages over other contrast-enhanced modalities, including real-time enhancement kinetics, decreased contrast reactions, and lack of renal toxicity. CEUS is especially useful in assessment of GU pathology, where it can be used intravascularly as well as intraluminally within the collecting system to augment the evaluation of multiple GU pathologies.

This article outlines a roadmap to achieving and maintaining excellence in an ultrasound (US) practice. We present constructive advice on how US practices can achieve and maintain quality, patient and referring physician satisfaction, and efficiency in the setting of rising examination volumes. Accreditation, sonographer and resident/fellow physician training, advanced practice sonographers, and Picture Archiving and Communication System/Artificial Intelligence in US are discussed. Advice for how to begin offering new US examinations, begin a practice at new US locations, improve quality assurance, and enhance marketing are covered.

Acute cholecystitis (AC) is a common yet challenging diagnosis in the emergency department (ED), with diverse sonographic parameters employed to enhance diagnostic accuracy. Recently, peak systolic cystic artery velocity (CaV) ≥ 40 cm/s has been proposed as a highly specific and an independent sonographic marker for AC in the emergency setting. To evaluate the diagnostic performance of CaV for AC and to assess the diagnostic utility of additional ultrasound parameters for the diagnosis of AC in the ED. This retrospective, single-institutional study analyzed ultrasound exams from 405 patients over one year. CaV was compared in patients diagnosed with AC on surgical pathology versus controls (subjects without presumed AC), employing statistical tools for data analysis including assessment of diagnostic efficacy of sonographic markers and multivariate logistic regression to assess true sonographic predictors of AC. CaV ≥ 40 cm/s demonstrated specificity and negative predictive value of 83.8

Background & aims: Abbreviated MRI (AMRI) has been proposed as an alternative to ultrasound for hepatocellular carcinoma (HCC) surveillance; however, comparative data for AMRI and ultrasound are needed. Thus, we evaluated the sensitivity and specificity of dynamic contrast-enhanced (DCE)-AMRI and ultrasound for early-stage HCC detection in patients with cirrhosis. Methods: We conducted a multicenter retrospective case-control study among patients with cirrhosis (cases with early-stage HCC as per Milan Criteria; controls without HCC) who underwent an ultrasound and a DCE-MRI within a 6-month period between 2012 and 2019. HCC diagnosis was confirmed by imaging alone in 85% and by histopathology in 15% of patients. Dynamic AMRI examinations were simulated from the full MRI by selecting relevant sequences. Independent, blinded interpretations of ultrasounds and AMRI results were performed using Liver Imaging Reporting and Data System algorithms. Ultrasounds were considered positive if US-3 observations were detected. AMRI was considered positive if LR-4, LR-5, or LR-M were detected. Per-patient sensitivity and specificity for early-stage HCC detection were estimated, and cross-modality differences were tested. Results: We included 216 cases and 432 controls. Patient-level sensitivity and specificity of AMRI were significantly higher compared with ultrasound: 80.1% (95% CI 76.1-83.6) vs. 71.1% (95% CI 66.6-75.2), p <0.001, and 91.9% (95% CI 89.9-93.5) vs. 72.3% (95% CI 69.3-75.2), p <0.001, respectively. AMRI sensitivity was significantly higher compared with ultrasound among patients with Child-Pugh B cirrhosis (80.8% vs. 57.4%, p <0.001) but not among those with Child-Pugh A (84.7% vs. 78.6%, p = 0.07) or Child-Pugh C cirrhosis (52.6% vs. 68.4%, p = 0.18). Conclusions: Dynamic AMRI may be more sensitive and specific for early-stage HCC detection in patients with cirrhosis compared with ultrasound, although its relative benefit might be smaller in patients with Child-Pugh A cirrhosis. Larger direct comparative data sets are needed, particularly among patients with Child-Pugh C cirrhosis who may benefit from alternative surveillance strategies.

PURPOSE:First-line imaging for diagnosis of deep vein thrombosis (DVT) is ultrasound. Although the Wells criteria and laboratory testing help inform best ordering practices, this investigation evaluates the influence of various patient and nonpatient factors on examination results. METHODS:The authors analyzed structured reports from all inpatient and emergency department ultrasound examinations across two institutions from 2015 to 2022. Examination, provider, and patient factors were compared with examination results for effect on examination results and intergroup variance. RESULTS:The overall rate of acute or new noncalf DVT was 10.4%. Rates of acute or new noncalf DVT were found to be higher in inpatients (versus emergency department patients), in upper extremities (versus lower extremities), in patients with lower body mass index values, among physicians (versus advanced practice providers), and when examinations were ordered by providers with fewer overall DVT ultrasound examinations ordered. Mixed results were observed for number of limbs examined and provider supervision status. Examination day of week and time of day were not significant. CONCLUSIONS:DVT ultrasound results varied according to examination-, facility-, patient-, and provider-level factors, which can inform institutional quality monitoring programs, resource utilization, and future investigations into factors that may influence diagnostic testing results.

Abdominal US is currently the best-validated surveillance strategy for hepatocellular carcinoma (HCC) in at-risk patients. It is the only modality shown to have completed all five phases of validation and can achieve high sensitivity and specificity for HCC detection, especially when conducted by expert sonographers in high-volume centers. However, US also has limitations, including operator dependency and varying sensitivity in clinical practice. Further, the sensitivity of US for early-stage HCC detection is lower in patients with obesity or nonviral liver disease, increasingly common populations undergoing surveillance. Imaging-based and blood-based surveillance strategies, including abbreviated MRI and biomarker panels, may overcome some limitations of US-based surveillance. Both strategies have promising test performance in phase II and phase III biomarker studies and are undergoing prospective validation. Considering the variation in HCC risk and test performance between patients, there will likely be a shift away from a one-size-fits-all approach and toward precision screening, in which the "best" test is selected based on individual patient characteristics. In this upcoming era of precision HCC screening among patients with cirrhosis, US will likely continue to have an important, albeit reduced, surveillance role.