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Khaled M Elsayes,1 Ania Z Kielar,2 Victoria Chernyak,3 Ali Morshid,1 Alessandro Furlan,4 William R Masch,5 Robert M Marks,6 Aya Kamaya,7 Richard KG Do,8 Yuko Kono,9 Kathryn J Fowler,9 An Tang,10 Mustafa R Bashir,11 Elizabeth M Hecht,12 Kedar Jambhekar,13 Andrej Lyshchik,14 Shuchi K Rodgers,14 Jay P Heiken,15 Marc Kohli,16 David T Fetzer,17 Stephanie R Wilson,18 Zahra Kassam,19 Mishal Mendiratta-Lala,5 Amit G Singal,17 Christopher S Lim,20 Irene Cruite,21 James Lee,22 Ryan Ash,23 Donald G Mitchell,14 Matthew DF McInnes,24 Claude B Sirlin9 1Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA; 2Department of Radiology, University of Toronto, ON, Canada; 3Department of Radiology, Montefiore Medical Center, Bronx, NY, USA; 4Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA; 5Department of Radiology, University of Michigan, Ann Arbor, MI, USA; 6Department of Radiology, Naval Medical Center San Diego, Uniformed Services University of the Health Sciences, Bethesda, MD, USA; 7Department of Radiology, Stanford University Medical Center, Stanford, CA, USA; 8Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA; 9Department of Radiology, University of California San Diego, CA, USA; 10Department of Radiology, Centre Hospitalier de l’Université de Montréal (CHUM), Montreal, QC, Canada; 11Department of Radiology, Center for Advanced Magnetic Resonance Development, and Division of Gastroenterology, Department of Medicine, Duke University Medical Center, Durham, NC, USA; 12Department of Radiology, Columbia University Medical Center, New York, NY, USA; 13Department of Radiology, University of Arkansas for Medical Sciences, Little Rock, AR, USA; 14Department of Radiology, Einstein Medical Center, Philadelphia, PA, USA; 15Department of Radiology, Mayo Clinic, Rochester, MN, USA; 16Department of Radiology, University of California San Francisco, CA, USA; 17Division of Digestive and Liver Diseases, UT Southwestern Medical Center, Dallas, TX, USA; 18Department of Radiology, University of Calgary, Calgary, AB, Canada; 19Department of Diagnostic Imaging, Schulich School of Medicine, London, ON, Canada; 20Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, ON, Canada; 21Department of Radiology, Inland Imaging, Spokane, WA, USA; 22Department of Radiology, University of Kentucky, Lexington, KY, USA; 23Department of Radiology, University of Kansas, Kansas City, KS, USA; 24Department of Radiology, University of Ottawa, ON, Canada Abstract: The Liver Imaging Reporting and Data System (LI-RADS®) is a comprehensive system for standardizing the terminology, technique, interpretation, reporting, and data collection of liver observations in individuals at high risk for hepatocellular carcinoma (HCC). LI-RADS is supported and endorsed by the American College of Radiology (ACR). Upon its initial release in 2011, LI-RADS applied only to liver observations identified at CT or MRI. It has since been refined and expanded over multiple updates to now also address ultrasound-based surveillance, contrast-enhanced ultrasound for HCC diagnosis, and CT/MRI for assessing treatment response after locoregional therapy. The LI-RADS 2018 version was integrated into the HCC diagnosis, staging, and management practice guidance of the American Association for the Study of Liver Diseases (AASLD). This article reviews the major LI-RADS updates since its 2011 inception and provides an overview of the currently published LI-RADS algorithms. Keywords: LI-RADS, v2018, CT, MRI, CEUS, US, HCC, liver imaging, reporting, cirrhosis

Ultrasound (US) is the imaging modality of choice for evaluation of superficial palpable lesions. A large proportion of these lesions have characteristic sonographic appearance and can be confidently diagnosed with US without the need for biopsy or other intervention. The Society of Radiologists in Ultrasound (SRU) recently published a Consensus Conference Statement on superficial soft tissue masses. The goal of this manuscript is (a) to serve as a sonographic pictorial review for palpable lesions based on the SRU statement, (b) present the typical sonographic features of palpable lesions that can be confidently diagnosed with US, and (c) provide an overview of other palpable lesions with a framework to interpret the US studies and advise on appropriate further management., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Imaging evaluation of the gallbladder is a fundamental skill in the majority of radiology practice. Due to ease of accessibility, low cost, lack of ionizing radiation, and excellent spatial resolution, ultrasound is often the first imaging modality used to evaluate the gallbladder. In this invited article we review and update how ultrasound can evaluate common pathologies including gallbladder polyps, tumefactive sludge, adenomyomatosis, and acute cholecystitis. We also discuss the role of Doppler, microvascular flow imaging, and contrast enhanced ultrasound in the sonographic assessment of the gallbladder., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Hepatocellular carcinoma (HCC) is a unique cancer allowing tumor diagnosis with identification of definitive patterns of enhancement on contrast-enhanced imaging, avoiding invasive biopsy. However, it is still unclear to what extent Contrast-Enhanced Ultrasound (CEUS) is a clinically useful additional step when Computed tomography (CT) or Magnetic resonance imaging (MRI) are inconclusive., Methods: A prospective international multicenter validation study for CEUS Liver Imaging Reporting and Data System (LI-RADS) was conducted between January 2018 and August 2021. 646 patients at risk for HCC with focal liver lesions were enrolled. CEUS was performed using an intravenous ultrasound contrast agent within 4 weeks of CT/MRI. Liver nodules were categorized based on LI-RADS (LR) criteria. Histology or one-year follow-up CT/MRI imaging results were used as the reference standard. The diagnostic performance of CEUS was evaluated for inconclusive CT/MRI scan in two scenarios for which the AASLD recommends repeat imaging or imaging follow-up: observations deemed non-characterizable (LR-NC) or with indeterminate probability of malignancy (LR-3)., Results: 75 observations on CT or MRI were categorized as LR-3 (n = 54) or LR-NC (n = 21) CEUS recategorization of such observations into a different LR category (namely, into one among LR-1, LR-2, LR-5, LR-M, or LR-TIV) resulted in management recommendation changes in 33.3% (25/75) and in all but one (96.0%, 24/25) observation, the new management recommendations were correct., Conclusion: CEUS LI-RADS resulted in management recommendations change in substantial number of liver observations with initial indeterminate CT/MRI characterization, identifying both non-malignant lesions and HCC, potentially accelerating the diagnostic process and alleviating the need for biopsy or follow-up imaging., Clinicaltrials: gov number, NCT03318380., (© 2024. The Author(s).)

The American College of Radiology Liver Imaging Reporting and Data System (LI-RADS) standardizes the imaging technique, reporting lexicon, disease categorization, and management for patients with or at risk for hepatocellular carcinoma (HCC). LI-RADS encompasses HCC surveillance with US; HCC diagnosis with CT, MRI, or contrast-enhanced US (CEUS); and treatment response assessment (TRA) with CT or MRI. LI-RADS was recently expanded to include CEUS TRA after nonradiation locoregional therapy or surgical resection. This report provides an overview of LI-RADS CEUS Nonradiation TRA v2024, including a lexicon of imaging findings, techniques, and imaging criteria for posttreatment tumor viability assessment. LI-RADS CEUS Nonradiation TRA v2024 takes into consideration differences in the CEUS appearance of viable tumor and posttreatment changes within and in close proximity to a treated lesion. Due to the high sensitivity of CEUS to vascular flow, posttreatment reactive changes commonly manifest as areas of abnormal perilesional enhancement without washout, especially in the first 3 months after treatment. To improve the accuracy of CEUS for nonradiation TRA, different diagnostic criteria are used to evaluate tumor viability within and outside of the treated lesion margin. Broader criteria for intralesional enhancement increase sensitivity for tumor viability detection. Stricter criteria for perilesional enhancement limit miscategorization of posttreatment reactive changes as viable tumor. Finally, the TRA algorithm reconciles intralesional and perilesional tumor viability assessment and assigns a single LI-RADS treatment response (LR-TR) category: LR-TR nonviable, LR-TR equivocal, or LR-TR viable., (© RSNA, 2024 See also the editorial by Milot in this issue.)

Objectives: The paralaryngeal muscles are thought to be hyperfunctional with phonation in patients with primary muscle tension dysphonia (pMTD). However, objective, quantitative tools to assess paralaryngeal movement patterns lack. The objectives of this study were to (1) validate the use of optical flow to characterize paralaryngeal movement patterns with phonation, (2) characterize phonatory optical flow velocities and variability of the paralaryngeal muscles before and after a vocal load challenge, and (3) compare phonatory optical flow measures to standard laryngoscopic, acoustic, and self-perceptual assessments., Methods: Phonatory movement velocities and variability of the paralaryngeal muscles at vocal onsets and offsets were quantified from ultrasound videos and optical flow methods across 42 subjects with and without a diagnosis of pMTD, before and after a vocal load challenge. Severity of laryngoscopic mediolateral supraglottic compression, acoustic perturbation, and ratings of vocal effort and discomfort were also obtained at both time points., Results: There were no significant differences in optical flow measures of the paralaryngeal muscles with phonation between patients with pMTD and controls. Patients with pMTD had significantly more supraglottic compression, higher acoustic perturbations, and higher vocal effort and vocal tract discomfort ratings. Vocal load had a significant effect on vocal effort and discomfort but not on supraglottic compression, acoustics, or optical flow measures of the paralaryngeal muscles., Conclusion: Optical flow methods can be used to study paralaryngeal muscle movement velocity and variability patterns during vocal productions, although the role of the paralaryngeal in pMTD diagnostics (e.g., vocal hyperfunction) remains suspect., Level of Evidence: 2 Laryngoscope, 134:1792-1801, 2024., (© 2023 The Authors. The Laryngoscope published by Wiley Periodicals LLC on behalf of The American Laryngological, Rhinological and Otological Society, Inc.)

Abstract: Percutaneous core-needle biopsy (PCNB) plays a growing and essential role in many medical specialties. Proper and effective use of various PCNB devices requires basic understanding of how they function. Current literature lacks a detailed overview and illustration of needle function and design differences, a potentially valuable reference for users ranging from early trainees to experts who are less familiar with certain devices. This pictorial aims to provide such an overview, using diagrams and magnified photographs to illustrate the intricate components of these devices. Following a brief historical review of biopsy needle technology for context, we emphasize distinctions in design between 2 major classes of PCNB devices (side- and end-cutting devices), focusing on practical implications for how each device is most effectively used. We believe a nuanced understanding of biopsy device function sheds light on certain lingering ambiguities in biopsy practice, such as the optimal needle gauge in organ biopsy, the benefits and risks associated with coaxial technique, the impact of needle selection and technique on bleeding, and the risk of unsuccessful sampling. In a subsequent pictorial, we will draw on the concepts presented here to illustrate examples of biopsy needle failure and how unrecognized needle failure can be an important and often preventable cause of increased biopsy risk and lower tissue yield., Competing Interests: The authors declare no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background and Aims: The objective of this study is to determine the diagnostic accuracy of the American College of Radiology Contrast-Enhanced Ultrasound (CEUS) Liver Imaging Reporting and Data System LR-5 characterization for HCC diagnosis in North American or European patients., Approach and Results: A prospective multinational cohort study was performed from January 2018 through November 2022 at 11 academic and nonacademic centers in North America and Europe. Patients at risk for HCC with at least 1 liver observation not previously treated, identified on ultrasound (US), or multiphase CT or MRI performed as a part of standard clinical care were eligible for the study. All participants were examined with CEUS of the liver within 4 weeks of CT/MRI or tissue diagnosis to characterize up to 2 liver nodules per participant using ACR CEUS Liver Imaging Reporting and Data System. Definite HCC diagnosis on the initial CT/MRI, imaging follow-up, or histology for CT/MRI-indeterminate nodules were used as reference standards. A total of 545 nodules had confirmed reference standards in 480 patients, 73.8% were HCC, 5.5% were other malignancies, and 20.7% were nonmalignant. The specificity of CEUS LR-5 for HCC was 95.1% (95% CI 90.1%-97.7%), sensitivity 62.9% (95% CI 57.9%-67.7%), positive predictive value 97.3% (95% CI 94.5%-98.7%), and negative predictive value 47.7% (95% CI 41.7%-53.8%). In addition, benign CEUS characterization (LR-1 or LR-2) had 100% specificity and 100% positive predictive value for nonmalignant liver nodules., Conclusions: CEUS Liver Imaging Reporting and Data System provides an accurate categorization of liver nodules in participants at risk for HCC., (Copyright © 2023 American Association for the Study of Liver Diseases.)

Diagnosing rare hematological malignancies in the liver is often challenging owing to their infrequency, and confirmation generally necessitates histological examination. Due to the rarity of these lesions, there are limited data concerning their appearance on ultrasound and, specifically, contrast-enhanced ultrasound. In this review, we describe the pathological and ultrasound features of several hematological malignant liver lesions, including lymphoma of the liver and chloroma. Furthermore, two specific forms of liver lymphoma are described: mucosa-associated lymphoid tissue (MALT) lymphoma andplasmacytoma of the liver.

Objectives: It has been assumed that patients with primary muscle tension dysphonia (pMTD) have more extrinsic laryngeal muscle (ELM) tension, but tools to study this phenomenon lack. Shear wave elastography (SWE) is a potential method to address these shortcomings. The objectives of this study were to apply SWE to the ELMs, compare SWE measures to standard clinical metrics, and determine group differences in pMTD and typical voice users before and after vocal load., Methods: SWE measurements of the ELMs from ultrasound examinations of the anterior neck, supraglottic compression severities from laryngoscopic images, cepstral peak prominences (CPP) from voice recordings, and self-perceptual ratings of vocal effort and discomfort were obtained in voice users with (N = 30) and without (N = 35) pMTD, before and after a vocal load challenge., Results: ELM tension significantly increased from rest-to-voiced conditions in both groups. However, the groups were similar in their ELM stiffness levels at SWE at baseline, during vocalization, and post-vocal load. Levels of vocal effort and discomfort and supraglottic compression were significantly higher and CPP was significantly lower in the pMTD group. Vocal load had a significant effect on vocal effort and discomfort but not on laryngeal or acoustic patterns., Conclusion: SWE can be used to quantify ELM tension with voicing. Although the pMTD group reported significantly higher levels of vocal effort and vocal tract discomfort and, on average, exhibited significantly more severe supraglottic compression and lower CPP values, there were no group differences in levels of ELM tension using SWE., Level of Evidence: 2 Laryngoscope, 133:3482-3491, 2023., (© 2023 The Authors. The Laryngoscope published by Wiley Periodicals LLC on behalf of The American Laryngological, Rhinological and Otological Society, Inc.)

Pelvic organ prolapse (POP) and stress urinary incontinence (SUI) are two common disorders that affect the anterior compartment of the pelvic floor in women. These can be treated conservatively or surgically. Among patients treated surgically, a substantial number present with pain, recurrent POP or SUI, or other conditions that warrant additional interventions. In many of these cases, imaging is key to identifying and characterizing the type of procedure performed, locating synthetic materials that may have been placed, and characterizing complications. Imaging may be particularly helpful when prior surgical records are not available or a comprehensive physical examination is not possible. US and MRI are the most commonly used modalities for such patients, although radiopaque surgical materials may be visible at voiding cystourethrography and CT. The authors summarize commonly used surgical treatment options for patients with SUI and POP, review imaging techniques for evaluation of such patients, and describe the normal imaging appearance and complications of pelvic floor surgical repair procedures in the anterior compartment of the pelvis. © RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Fatty liver disease has a high and increasing prevalence worldwide, is associated with adverse cardiovascular events and higher long-term medical costs, and may lead to liver-related morbidity and mortality. There is an urgent need for accurate, reproducible, accessible, and noninvasive techniques appropriate for detecting and quantifying liver fat in the general population and for monitoring treatment response in at-risk patients. CT may play a potential role in opportunistic screening, and MRI proton-density fat fraction provides high accuracy for liver fat quantification; however, these imaging modalities may not be suited for widespread screening and surveillance, given the high global prevalence. US, a safe and widely available modality, is well positioned as a screening and surveillance tool. Although well-established qualitative signs of liver fat perform well in moderate and severe steatosis, these signs are less reliable for grading mild steatosis and are likely unreliable for detecting subtle changes over time. New and emerging quantitative biomarkers of liver fat, such as those based on standardized measurements of attenuation, backscatter, and speed of sound, hold promise. Evolving techniques such as multiparametric modeling, radiofrequency envelope analysis, and artificial intelligence-based tools are also on the horizon. The authors discuss the societal impact of fatty liver disease, summarize the current state of liver fat quantification with CT and MRI, and describe past, currently available, and potential future US-based techniques for evaluating liver fat. For each US-based technique, they describe the concept, measurement method, advantages, and limitations. © RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Contrast-enhanced US (CEUS), similar to other radiologic modalities, requires specific technical considerations and is subject to image artifacts. These artifacts may affect examination quality, negatively impact diagnostic accuracy, and decrease user comfort when using this emerging technique. Some artifacts are related to commonly known gray-scale US artifacts that can also appear on the contrast-only image (tissue-subtracted image obtained with the linear responses from background tissues nulled). These may include acoustic shadowing and enhancement; reverberation, refraction, and reflection; and poor penetration. Other artifacts are exclusive to CEUS owing to the techniques used for contrast mode image generation and the unique properties of the microbubbles that constitute ultrasound-specific contrast agents (UCAs). UCA-related artifacts may appear on the contrast-only image, the gray-scale image, or various Doppler mode images. Artifacts related to CEUS may include nonlinear artifacts and unintentional microbubble destruction resulting in pseudowashout. The microbubbles themselves may result in specific artifacts such as pseudoenhancement, signal saturation, and attenuation and shadowing and can confound the use of color and spectral Doppler US. Identifying and understanding these artifacts and knowing how to mitigate them may improve the quality of the imaging study, increase user confidence, and improve patient care. The authors review the principles of UCAs and the sound-microbubble interaction, as well as the technical aspects of image generation. Technical considerations, including patient positioning, depth, acoustic window, and contrast agent dose, also are discussed. Specific artifacts are described, with tips on how to identify and, if necessary, apply corrective measures, with the goal of improving examination quality. © RSNA, 2022 Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

Gallbladder polyps (also known as polypoid lesions of the gallbladder) are a common incidental finding. The vast majority of gallbladder polyps smaller than 10 mm are not true neoplastic polyps but are benign cholesterol polyps with no inherent risk of malignancy. In addition, recent studies have shown that the overall risk of gallbladder cancer is not increased in patients with small gallbladder polyps, calling into question the rationale for frequent and prolonged follow-up of these common lesions. In 2021, a Society of Radiologists in Ultrasound, or SRU, consensus conference was convened to provide recommendations for the management of incidentally detected gallbladder polyps at US. See also the editorial by Sidhu and Rafailidis in this issue., (© RSNA, 2022.)

Excessive liver fat (steatosis) is now the most common cause of chronic liver disease worldwide and is an independent risk factor for cirrhosis and associated complications. Accurate and clinically useful diagnosis, risk stratification, prognostication, and therapy monitoring require accurate and reliable biomarker measurement at acceptable cost. This article describes a joint effort by the American Institute of Ultrasound in Medicine (AIUM) and the RSNA Quantitative Imaging Biomarkers Alliance (QIBA) to develop standards for clinical and technical validation of quantitative biomarkers for liver steatosis. The AIUM Liver Fat Quantification Task Force provides clinical guidance, while the RSNA QIBA Pulse-Echo Quantitative Ultrasound Biomarker Committee develops methods to measure biomarkers and reduce biomarker variability. In this article, the authors present the clinical need for quantitative imaging biomarkers of liver steatosis, review the current state of various imaging modalities, and describe the technical state of the art for three key liver steatosis pulse-echo quantitative US biomarkers: attenuation coefficient, backscatter coefficient, and speed of sound. Lastly, a perspective on current challenges and recommendations for clinical translation for each biomarker is offered., (© RSNA, 2022.)

Contrast-enhanced intraoperative ultrasound (CE-IOUS) is a relatively new but valuable tool that is increasingly used as an adjunct to computed tomography, MRI, and IOUS for patients undergoing liver surgery. CE-IOUS has an important role in 2 main settings: the discrimination of indeterminate lesions detected in cirrhotic livers by conventional IOUS and in the detection of colorectal liver metastasis that may be overlooked by other imaging modalities. The intraoperative nature of the imaging and interpretation allows for CE-IOUS to directly affect surgical decision-making that may importantly affect patient outcomes., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2022 Elsevier Inc. All rights reserved.)

With the increasing availability of contrast-enhanced US (CEUS) worldwide and in the United States, the potential applications of this modality in abdominal imaging and intervention are continuing to expand. CEUS leverages the many inherent benefits of US with a safe and unique microbubble contrast agent. When injected intravenously, US contrast agents (UCAs) function as a pure blood pool agent, augmenting diagnostic US examinations such as vascular imaging. In the procedure suite, UCA can be used to improve needle visualization and depict active extravasation. UCA may also be injected through needles and tubes into various body spaces, allowing the assessment of the urinary system, indwelling catheters, and other tracts and cavities. Some venous and lymphatic lesions may be diagnosed with the direct injection of a UCA into these lesions. The authors highlight some of the many applications that are relevant to the abdominal imaging professional and interventional radiologist but should not be considered a complete list, and users of UCAs should continue to consider uses beyond those traditionally highlighted in recent literature. Online supplemental material is available for this article. © RSNA, 2022.

BACKGROUND. The American College of Radiology Ultrasound LI-RADS includes the visualization score as a subjective measure of examination quality and the expected level of sensitivity. Whether a single suboptimal visualization score warrants a change in surveillance strategy is unknown. OBJECTIVE. The purpose of this study is to determine the relative stability of visualization scores on serial surveillance ultrasound examinations in patients at risk for HCC. METHODS. This retrospective study included patients at risk for HCC who underwent at least two HCC surveillance ultrasound examinations at one of three institutions between January 2017 and November 2020. The frequencies of the score remaining unchanged after variable numbers of preceding examinations with the given score were determined. A mixed-effects logistic model was fitted to identify factors associated with a repeat score of C (denoting severe limitations) versus a change to score A (indicating no or minimal limitations) or score B (denoting moderate limitations). RESULTS. A total of 3169 patients underwent at least two ultrasound examinations, yielding a total of 9602 examinations. A total of 8030 examinations (83.6%) were assigned score A; 1378 (14.4%), score B; and 194 (2.0%), score C. The frequency of score A was 88%, 91%, and 93% after one, two, and three consecutive prior examinations with score A, respectively. The frequency of score B was 45%, 48%, and 55% after one, two, and three consecutive prior examinations with score B. The frequency of score C was 42%, 67%, and 80% after one, two, and three consecutive prior examinations with score C. Among 109 examinations with score C in 91 patients with an available follow-up examination, no factor (including age, sex, severe steatosis, advanced cirrhosis, ascites, body mass index, and a change in the ultrasound machine, sonographer, or radiologist) was significantly associated with repeat score C (all p > .05). Although not statistically significant, presence of severe steatosis and presence of advanced cirrhosis had the highest odds ratios (2.88 and 2.38, respectively) for repeat score C in multivariable analysis. CONCLUSION. Only 42% of patients with visualization score C on a single surveillance examinations have score C on follow-up examinations; however, after two or more score C examinations, the chance of future score C substantially increases. CLINICAL IMPACT. The findings may inform decisions regarding alternative surveillance strategies in patients with visualization score C on ultrasound. This decision should consider the number of previous examinations with score C.

Contrast-enhanced ultrasound (CEUS) is increasingly performed for focal liver lesion evaluation because of its high safety profile and ability to yield a definitive diagnosis in many patients, obviating multiphase CT or MRI. CEUS uses specific ultrasound contrast agents (UCAs) that are exceedingly safe, without the risk of renal or liver toxicity. UCAs are cleared rapidly from the body, allowing for multiple injections during a single examination, with no potential for deposition in the patient. This review highlights the performance of CEUS for liver lesion evaluation and illustrates the imaging appearance of common liver lesions in children and adults., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Liver imaging plays a vital role in the management of patients at risk for hepatocellular carcinoma (HCC); however, progress in the field is challenged by nonuniform and inconsistent terminology in the published literature. The Steering Committee of the American College of Radiology (ACR)'s Liver Imaging Reporting And Data System (LI-RADS), in conjunction with the LI-RADS Lexicon Writing Group and the LI-RADS International Working Group, present this consensus document to establish a single universal liver imaging lexicon. The lexicon is intended for use in research, education, and clinical care of patients at risk for HCC (i.e., the LI-RADS population) and in the general population (i.e., even when LI-RADS algorithms are not applicable). We anticipate that the universal adoption of this lexicon will provide research, educational, and clinical benefits. KEY POINTS: •To standardize terminology, we encourage authors of research and educational materials on liver imaging to use the standardized LI-RADS Lexicon. •We encourage reviewers to promote the use of the standardized LI-RADS Lexicon for publications on liver imaging. •We encourage radiologists to use the standardized LI-RADS Lexicon for liver imaging in clinical care., (© 2022. The Author(s), under exclusive licence to European Society of Radiology.)

Background & Aims: Identifying patients in whom ultrasound may be inadequate to exclude the presence of hepatocellular carcinoma (HCC) can inform interventions to improve screening effectiveness. We aimed to characterize correlates of suboptimal ultrasound quality and changes in ultrasound quality over time in patients with cirrhosis undergoing HCC screening., Methods: We performed a retrospective cohort study of patients with cirrhosis who underwent ultrasound examination at 2 large health systems between July 2016 and July 2019. Exam adequacy was graded by radiologists using the LI-RADS Visualization Score (A, B, C); we evaluated changes in visualization over time among patients with >1 ultrasound exams. We performed multivariable logistic regression to identify characteristics associated with limited ultrasound visualization (scores B or C)., Results: Of 2053 cirrhosis patients, 1685 (82.1%) had ultrasounds with score A, 262 (12.8%) had score B, and 106 (5.2%) had score C. Limited visualization was associated with alcohol-related or nonalcoholic fatty liver disease cirrhosis and presence of class II-III obesity. Among 1546 patients with >1 ultrasounds, 1129 (73.0%) had the same visualization score on follow-up (1046 score A, 60 score B, 23 score C). However, 255 (19.6%) of 1301 with score A at baseline had limited visualization when repeated (230 score B, 25 score C), and 130 (53.1%) of 245 patients with baseline limited visualization had good visualization when repeated., Conclusions: Nearly 1 in 5 patients with cirrhosis had moderately-severely limited ultrasound visualization for HCC nodules, particularly those with obesity or alcohol-related or nonalcoholic fatty liver disease cirrhosis. Ultrasound quality can change between exams, including improvement in many patients with limited visualization., (Copyright © 2022 AGA Institute. Published by Elsevier Inc. All rights reserved.)

BACKGROUND. When performing ultrasound (US) for hepatocellular carcinoma (HCC) screening, numerous factors may impair hepatic visualization, potentially lowering sensitivity. US LI-RADS includes a visualization score as a technical adequacy measure. OBJECTIVE. The purpose of this article is to identify associations between examination, sonographer, and radiologist factors and the visualization score in liver US HCC screening. METHODS. This retrospective study included 6598 patients (3979 men, 2619 women; mean age, 58 years) at risk for HCC who underwent a total of 10,589 liver US examinations performed by 91 sonographers and interpreted by 50 radiologists. Visualization scores (A, no or minimal limitations; B, moderate limitations; C, severe limitations) were extracted from clinical reports. Patient location (emergency department [ED], in-patient, outpatient), sonographer and radiologist liver US volumes during the study period (< 50, 50-500, > 500 examinations), and radiologist practice pattern (US, abdominal, community, interventional) were recorded. Associations with visualization scores were explored. RESULTS. Frequencies of visualization scores were 71.5%, 24.2%, and 4.2% for A, B, and C, respectively. Scores varied significantly ( p < .001) between examinations performed in ED patients (49.8%, 40.1%, and 10.2%), inpatients (58.8%, 33.9%, and 7.3%), and outpatients (76.7%, 20.3%, and 2.9%). Scores also varied significantly ( p < .001) by sonographer volume (< 50 examinations: 58.4%, 33.7%, and 7.9%; > 500 examinations: 72.9%, 22.5%, and 4.6%); reader volume (< 50 examinations: 62.9%, 29.9%, and 7.1%; > 500 examinations: 67.3%, 28.0%, and 4.7%); and reader practice pattern (US: 74.5%, 21.3%, and 4.3%; abdominal: 67.0%, 28.1%, and 4.8%; community: 75.2%, 21.9%, and 2.9%; interventional: 68.5%, 24.1%, and 7.4%). In multivariable analysis, independent predictors of score C were patient location (ED/inpatient: odds ratio [OR], 2.62; p < .001) and sonographer volume (< 50: OR, 1.55; p = .01). Among sonographers performing 50 or more examinations, the percentage of outpatient examinations with score C ranged from 0.8% to 5.4%; 9/33 were above the upper 95% CI of 3.2%. CONCLUSION. The US LI-RADS visualization score may identify factors affecting quality of HCC screening examinations and identify outlier sonographers in terms of poor examination quality. The approach also highlights potential systematic biases among radiologists in their quality assessment process. CLINICAL IMPACT. These findings may be applied to guide targeted quality improvement efforts and establish best practices and performance standards for screening programs.

Abstract: Hemangioma is the most common benign liver tumor and is frequently encountered as an incidental finding on imaging. The classic enhancement pattern of hemangioma is diagnostic on contrast-enhanced ultrasound (CEUS), and it follows the same pattern of enhancement on computed tomography and magnetic resonance imaging. However, there is a subset of hemangiomas that demonstrate atypical enhancement patterns on CEUS. The ability to recognize the different enhancement patterns and discern when additional imaging or biopsy may be necessary is essential to accurately interpret an atypical hemangioma on CEUS. This article reviews various enhancement patterns of hemangioma on CEUS to avoid pitfalls in characterization of focal liver lesions on CEUS., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Abstract: Gallbladder polyps (GPs) are a common incidental finding on ultrasound; however, important differences in recommended management exist among professional society guidelines.An electronic survey was sent to 189 fellows of the Society of Radiologists in Ultrasound. Main outcomes included preferences and current practice patterns for evaluation, management, and surveillance of GPs as well as personal lifetime experience with gallbladder sonography and GPs.A total of 64 subjects (34%) with experience in gallbladder sonography completed the study. The estimated combined total number of gallbladder scans seen by the responders was 3,071,880. None of fellows had ever seen a pedunculated GP <1 cm detected on ultrasound that was proven to be malignant at the time of detection or during subsequent follow-up. All of the fellows used size as a feature to stratify recommendations. The median size threshold currently used by Society of Radiologists in Ultrasound fellows for recommending ultrasound follow-up was 6 mm, and their preferred threshold was 7 mm. The median size threshold for recommending surgical consultation was 10 mm, and the preferred threshold was 10 mm. Wall thickening and shape were considered important factors by 76% and 67% of respondents, respectively.Society of Radiologists in Ultrasound fellows tend to provide recommendations most similar to the American College of Radiology and Canadian Association of Radiology guidelines for management of GPs. Many would prefer guidelines that result in fewer recommendations for follow-up and surgical consultation. Despite a substantial combined experience, this survey did not uncover any case of a small GP that was malignant., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Ultrasound visualisation is limited in approximately 20% of patients with cirrhosis undergoing hepatocellular carcinoma (HCC) surveillance; however, it is unknown if impaired visualisation directly impacts test performance. We aimed to evaluate the association between ultrasound visualisation and surveillance test performance., Methods: We performed a retrospective cohort study among patients with cirrhosis, with or without HCC, who underwent ultrasound-based surveillance at two large health systems between July 2016 and July 2019. Ultrasound visualisation assessment was recorded by interpreting radiologists using the ultrasound LI-RADS Visualisation score. We performed logistic regression analyses to evaluate the association between ultrasound visualisation and diagnostic test performance. We assessed sensitivity for HCC detection among ultrasounds performed in the year prior to HCC diagnoses and specificity using ultrasounds in those without HCC., Results: Among 186 patients with HCC, severely limited visualisation (Vis Score C) on ultrasound prior to HCC diagnosis was associated with increased odds of false-negative results, that is lower sensitivity (OR 7.94, 95% CI 1.23-51.16) in multivariable analysis. Ultrasound sensitivity with visualisation scores A or B exceeded 75%, compared to only 27.3% with visualisation score C. Among 2052 cirrhosis patients without HCC, moderate visualisation limitations (Vis score B) were associated with increased odds of false-positive results (OR 1.60, 1.13-2.27), although specificity exceeded 95% across all visualisation scores., Conclusions: Impaired ultrasound visualisation is associated with worse surveillance test performance. Alternative blood-based biomarkers and imaging strategies are needed for patients at risk for ultrasound-based surveillance failure., (© 2022 John Wiley & Sons Ltd.)

In this article, we demonstrate the use of a software-based radiologist reporting tool for the implementation of American College of Radiology Thyroid Imaging, Reporting and Data System thyroid nodule risk-stratification. The technical details are described with emphasis on addressing the information security and patient privacy issues while allowing it to integrate with the electronic health record and radiology reporting dictation software. Its practical implementation is assessed in a quality improvement project in which guideline adherence and recommendation congruence were measured pre and post implementation. The descriptions of our solution and the release of the open-sourced codes may be helpful in future implementation of similar web-based calculators., (© 2021. The Author(s) under exclusive licence to Society for Imaging Informatics in Medicine.)

The Ultrasound Liver Imaging Reporting and Data System (US LI-RADS), introduced in 2017 by the American College of Radiology, standardizes the technique, interpretation, and reporting of screening and surveillance ultrasounds intended to detect hepatocellular carcinoma in high-risk patients. These include patients with cirrhosis of any cause as well as subsets of patients with chronic hepatitis B viral infection. The US LI-RADS scheme is composed of an ultrasound category and a visualization score: ultrasound categories define the exam as negative, subthreshold, or positive and direct next steps in management; visualization scores denote the expected sensitivity of the exam, based on adequacy of liver visualization with ultrasound. Since its introduction, multiple institutions across the United States have implemented US LI-RADS. This review includes a background of hepatocellular carcinoma and US LI-RADS, definition of screening/surveillance population, recommendations and tips for technique, interpretation, and reporting, and preliminary outcomes analysis., (Published by Elsevier Inc.)

Liver lesions have different enhancement patterns at dynamic contrast-enhanced imaging. The Liver Imaging Reporting and Data System (LI-RADS) applies the enhancement kinetic of liver observations in its algorithms for imaging-based diagnosis of hepatocellular carcinoma (HCC) in at-risk populations. Therefore, careful analysis of the spatial and temporal features of these enhancement patterns is necessary to increase the accuracy of liver mass characterization. The authors focus on enhancement patterns that are found at or around the margins of liver observations-many of which are recognized and defined by LI-RADS, such as targetoid appearance, rim arterial phase hyperenhancement, peripheral washout, peripheral discontinuous nodular enhancement, enhancing capsule appearance, nonenhancing capsule appearance, corona enhancement, and periobservational arterioportal shunts-as well as peripheral and periobservational enhancement in the setting of posttreatment changes. Many of these are considered major or ancillary features of HCC, ancillary features of malignancy in general, features of non-HCC malignancy, features associated with benign entities, or features related to treatment response. Distinction between these different patterns of enhancement can help with achieving a more specific diagnosis of HCC and better assessment of response to local-regional therapy. © RSNA, 2021.

Contrast-enhanced ultrasound (CEUS) is a safe adjunct tool for liver imaging and can be an alternative to computed tomography or MR imaging. CEUS has a proven track record in guiding management for patients with chronic liver disease who need further evaluation of focal liver lesions. CEUS is a dynamic examination with high temporal and spatial resolution. CEUS uses a pure blood pool contrast agent that allows for a unique evaluation of the perfusion kinetics of a region of interest., Competing Interests: Disclosure D. Fetzer: Research agreements, Philips Healthcare and Siemens Healthineers. S. Spann: None., (Copyright © 2021 Elsevier Inc. All rights reserved.)

BACKGROUND. Incidental homogeneous renal masses are frequently encountered at portal venous phase CT. The American College of Radiology Incidental Findings Committee's white paper on renal masses recommends additional imaging for incidental homogeneous renal masses greater than 20 HU, but single-center data and the Bosniak classification version 2019 suggest the optimal attenuation threshold for detecting solid masses should be higher. OBJECTIVE. The purpose of this article is to determine the clinical importance of small (10-40 mm) incidentally detected homogeneous renal masses measuring 21-39 HU at portal venous phase CT. METHODS. We performed a 12-institution retrospective cohort study of adult patients who underwent portal venous phase CT for a nonrenal indication. The date of the first CT at each institution ranged from January 1, 2008, to January 1, 2014. Consecutive reports from 12,167 portal venous phase CT examinations were evaluated. Images were reviewed for 4529 CT examinations whose report described a focal renal mass. Eligible masses were 10-40 mm, well-defined, subjectively homogeneous, and 21-39 HU. Of these, masses that were shown to be solid without macroscopic fat; classified as Bosniak IIF, III, or IV; or confirmed to be malignant were considered clinically important. The reference standard was renal mass protocol CT or MRI, ultrasound of definitively benign cysts or solid masses, single-phase contrast-enhanced CT or unenhanced MRI showing no growth or morphologic change for 5 years or more, or clinical follow-up 5 years or greater. A reference standard was available for 346 masses in 300 patients. The 95% CIs were calculated using the binomial exact method. RESULTS. Eligible masses were identified in 4.2% of patients (514/12,167; 95% CI, 3.9-4.6%). Of 346 masses with a reference standard, none were clinically important (0%; 95% CI, 0-0.9%). Mean mass size was 17 mm; 72% (248/346) measured 21-30 HU, and 28% (98/346) measured 31-39 HU. CONCLUSION. Incidental small homogeneous renal masses measuring 21-39 HU at portal venous phase CT are common and highly likely benign. CLINICAL IMPACT. The change in attenuation threshold signifying the need for additional imaging from greater than 20 HU to greater than 30 HU proposed by the Bosniak classification version 2019 is supported.

Purpose: To determine the prevalence of isolated right-sided varicocele due to an obstructing malignancy in patients with no other evidence of malignancy., Methods: This retrospective, multi-institutional study included a text search for right-sided varicocele in consecutive reports of scrotal ultrasound studies performed between 4/22/1999 and 06/24/2018. Diagnosis was confirmed by a radiologist based on the following criteria: pampiniform plexus vein diameter of ≥ 2 mm, which has augmented flow or increases by ≥ 1 mm on Valsalva. Inclusion criteria for adequate follow-up were (1) abdominopelvic CT or MRI performed within 3 months prior to, or any time after, the ultrasound study; or (2) presence of clinical documentation more than 2 years after the ultrasound date. Exclusion criteria were existing cancer diagnosis in the abdomen or pelvis, epididymo-orchitis, intratesticular or intrascrotal mass, and prior scrotal surgery. Images of available CT or MRI studies were reviewed for presence of any explanation of right-sided varicocele., Results: 210 patients with right-sided varicocele met inclusion and exclusion criteria. 118/210 had abdominopelvic CT or MRI in the assigned timeframe. Of these, no patients had malignancy that could account for right-sided varicoceles. Of the 92/210 patients without CT or MRI but with available clinical follow-up, none had a malignancy that could have caused an isolated right-sided varicocele. There was no underlying malignancy to explain the right-sided varicocele in any of the patients, 0/210, 95% CI [0.0-1.4%]., Conclusion: No associated malignancy was found in patients with isolated right-sided varicoceles to support additional imaging for malignancy screening.

Objectives: To report results from a quality improvement (QI) project evaluating diagnostic performance, hospital resource use, and patient response data for postoperative contrast-enhanced ultrasound (CEUS) antegrade nephrostogram after percutaneous nephrolithotomy., Methods: For this Health Insurance Portability and Accountability Act-compliant, Institutional Review Board-approved study, QI data were deidentified and analyzed. On the first postoperative day after percutaneous nephrolithotomy, patients underwent both CEUS and fluoroscopic antegrade nephrostogram. For CEUS, 1.0 mL of Lumason (sulfur hexafluoride lipid type A microspheres; Bracco Diagnostics, Inc, Monroe Township, NJ) was injected via an indwelling nephrostomy tube, with ureteral patency confirmed by identifying intravesical ultrasound (US) contrast. Diagnostic performance for ureteral patency and contrast extravasation was calculated (with fluoroscopy as the reference standard). The examination time, room time, physician time, hospital costs, and patient response data were compared. The mean, standard deviation, 95% confidence interval, differences in mean, and 95% confidence interval of differences were calculated., Results: Eighty-one examinations were performed in 73 patients during the QI period. The sensitivity and specificity of CEUS for ureteral patency were 96% and 57%, respectively. There was no significant difference in time metrics between modalities, and the cost analysis showed lower direct and indirect costs for CEUS. Patient responses revealed lower levels of comfort for CEUS relative to fluoroscopy, without significant differences in reported pain or effort levels., Conclusions: Contrast-enhanced US showed very high sensitivity for ureteral patency; the relatively low specificity may have resulted from false-negative results in fluoroscopy. The hospital costs and resource use of CEUS compared favorably to fluoroscopy. Contrast-enhanced US also offers inherent advantages, including portability and lack of ionizing radiation., (© 2020 American Institute of Ultrasound in Medicine.)

Purpose: The SARS-CoV-2 pandemic has drastically disrupted radiology in-person education. The purpose of this study was to assess the implementation of a virtual teaching method using available technology and its role in the continuity of education of practicing radiologists and trainees during the pandemic., Methods: The authors created the Online Liver Imaging Course (OLIC) that comprised 28 online comprehensive lectures delivered in real-time and on-demand over six weeks. Radiologists and radiology trainees were asked to register to attend the live sessions. At the end of the course, we conducted a 46-question survey among registrants addressing their training level, perception of virtual conferencing, and evaluation of the course content., Results: One thousand four hundred and thirty four radiologists and trainees completed interest sign up forms before the start of the course with the first webinar having the highest number of live attendees (343 people). On average, there were 89 live participants per session and 750 YouTube views per recording (as of July 9, 2020). After the end of the course, 487 attendees from 37 countries responded to the postcourse survey for an overall response rate of (33%). Approximately (63%) of participants were practicing radiologists while (37%) were either fellows or residents and rarely medical students. The overwhelming majority (97%) found the OLIC webinar series to be beneficial. Essentially all attendees felt that the webinar sessions met (43%) or exceeded (57%) their expectations. When asked about their perception of virtual conferences after attending OLIC lectures, almost all attendees (99%) enjoyed the virtual conference with a majority (61%) of the respondents who enjoyed the virtual format more than in-person conferences, while (38%) enjoyed the webinar format but preferred in-person conferences. When asked about the willingness to attend virtual webinars in the future, (84%) said that they would attend future virtual conferences even if in-person conferences resume while (15%) were unsure., Conclusion: The success of the OLIC, attributed to many factors, indicates that videoconferencing technology provides an inexpensive alternative to in-person radiology conferences. The positive responses to our postcourse survey suggest that virtual education will remain to stay. Educational institutions and scientific societies should foster such models., (Copyright © 2020 The Association of University Radiologists. All rights reserved.)

Ultrasound plays an essential role in the initial evaluation of patients with suspected or confirmed acute pancreatitis. In addition to evaluation of the pancreatic parenchyma, ultrasound is used for assessment of the gallbladder, biliary tree, peripancreatic tissues, and regional vascular structures. While enlarged and edematous pancreas are classic sonographic features of acute pancreatitis, the pancreas may appear sonographically normal in the setting of acute pancreatitis. Nonetheless, sonographic evaluation in this setting is valuable because assessment for etiologic factors such as gallstones or evidence of biliary obstruction are best performed with ultrasound. Complications of pancreatitis such as peripancreatic fluid collections, venous thrombosis, or arterial pseudoaneurysm can be identified with careful and focused ultrasound examination. Knowledge of various scanning techniques can help to mitigate some of the commonly encountered barriers to sonographic visualization of the pancreas and right upper quadrant structures. Ultrasound can also be used for guidance of percutaneous treatment such as drainage of fluid collections or pseudoaneurysm thrombosis. Difficulty in differentiating edematous from necrotizing pancreatitis can be mitigated with the use of contrast-enhanced ultrasound to assess pancreatic parenchymal enhancement.

US is a powerful and nearly ubiquitous tool in the practice of interventional radiology. Use of contrast-enhanced US (CEUS) has gained traction in diagnostic imaging given the recent approval by the U.S. Food and Drug Administration (FDA) of microbubble contrast agents for use in the liver, such as sulfur hexafluoride lipid-type A microspheres. Adoption of CEUS by interventional radiologists can enhance not only procedure guidance but also preprocedure patient evaluation and assessment of treatment response across a wide spectrum of oncologic, vascular, and nonvascular procedures. In addition, the unique physical properties of microbubble contrast agents make them amenable as therapeutic vehicles in themselves, which can lay a foundation for future therapeutic innovations in the field in drug delivery, thrombolysis, and vascular flow augmentation. The purpose of this article is to provide an introduction to and overview of CEUS aimed at the interventional radiologist, highlighting its role before, during, and after frequently practiced oncologic and vascular interventions such as biopsy, ablation, transarterial chemoembolization, detection and control of hemorrhage, evaluation of transjugular intrahepatic portosystemic shunts (TIPS), detection of aortic endograft endoleak, thrombus detection and evaluation, evaluation of vascular malformations, lymphangiography, and percutaneous drain placement. Basic physical principles of CEUS, injection and scanning protocols, and logistics for practice implementation are also discussed. Early adoption of CEUS by the interventional radiology community will ensure rapid innovation of the field and development of future novel procedures. Online supplemental material is available for this article. © RSNA, 2020.

Background: The high operational cost of MRI limits its utility for hepatocellular carcinoma (HCC) screening. Abbreviated-protocol dynamic contrast-enhanced MRI (aMRI) may help lower cost while maintaining the high accuracy of complete-protocol diagnostic MRI (cMRI)., Purpose: To compare aMRI to cMRI for HCC detection in cirrhosis patients., Study Type: Cross-sectional study., Study Population: Cirrhosis patients undergoing MRI for suspected HCC., Field Strength/sequence: 1.5T and 3T; aMRI (coronal T 2 -weighted, axial dynamic contrast-enhanced T 1 -weighted fat-suppressed sequences); cMRI (aMRI sequences and unenhanced axial T 2 -, T 1 -, and diffusion-weighted sequences)., Assessment: From each cMRI, an abbreviated exam was created by extracting only the aMRI sequences. Five radiologists independently reviewed aMRI and cMRI and assigned per-patient screening results by the presence/absence of any actionable observation per Liver Imaging and Reporting Data System v2018 (LI-RADS 4, 5, M, or TIV categories). Per-patient HCC status was determined by the composite reference standard of histopathology, follow-up imaging, consensus expert panel imaging review, and clinical follow-up., Statistical Tests: Interreader agreement between aMRI and cMRI was compared with that of cMRI and tested for interchangeability against a tolerance margin of 0.05. Per-patient screening sensitivity, specificity, and accuracy were compared between aMRI and cMRI and tested for equivalence against a tolerance margin of 0.05., Results: In 93 cirrhosis patients, five radiologists recorded on average 121 liver observations. Interreader screening agreement probability (and 95% confidence interval confidence interval [CI]) was 0.914 [0.900, 0.926] between aMRI and cMRI, and 0.927 [0.908, 0.942] for cMRI; their difference was within the 0.05 margin for interchangeability. In 86 patients in whom a final HCC status could be determined, the detection sensitivity and specificity of aMRI was 0.921 [0.864, 0.956] and 0.886 [0.844, 0.918], within the 5% equivalence margin to cMRI, 0.936 [0.881, 0.965] and 0.883 [0.840, 0.915], respectively., Data Conclusion: Abbreviated-protocol screening MRI is interchangeable with, and equivalent to, complete-protocol diagnostic MRI for per-patient HCC detection in cirrhosis., Level of Evidence: 4 Technical Efficacy: Stage 6 J. Magn. Reson. Imaging 2020;51:415-425., (© 2019 International Society for Magnetic Resonance in Medicine.)

Purpose: To determine the prevalence and clinical significance of discordant LI-RADS ® (Liver Imaging Reporting and Data System) liver observations on multiphase contrast-enhanced (MCE) magnetic resonance imaging (MRI) in patients with cirrhosis., Methods: This cross-sectional study included 93 cirrhosis patients who underwent 1.5 or 3 T MCE MRI for evaluation of hepatocellular carcinoma (HCC). Two abdominal radiologists independently reviewed T1-, T2-, diffusion-weighted unenhanced images as well as MCE T1-weighted fat-suppressed images and reported liver observations using LI-RADS ® . Concordance were recorded for detection (co-detected by both radiologists or not), size category (< 10; 10-19; ≥ 20 mm), and LI-RADS ® category assignment as reportable (LR-3/4/5/M) and actionable (LR-4/5/M). The overall concordance (i.e., concordant in detection, size, and LR-category) was calculated with 95% confidence interval [CI], and separately for detection, size, and LR-category. Clinical significance of discordance was assessed as impact on follow-up imaging, referral for biopsy, liver transplant eligibility, or treatment modality., Results: Reportable and actionable observations were overall concordant between two radiologists only in 32.3% [24.6, 41.0] and 40.1% [29.5, 51.5] of cases, respectively. Poor overall concordance was related to detection concordance of 52.0% [44.3, 59.5] and 62.5% [52.3, 71.8], as well as LR-category concordance of 73.7% [61.6, 83.1] and 70.9% [57.3, 81.6], for reportable and actionable observations, respectively. Discordant LI-RADS ® observations would have impacted clinical management in 30 subjects (43.5%), most (66.7%) of whom were due to discordant detection., Conclusion: Discordant MRI LI-RADS ® observations are common in patients with cirrhosis and may have potential implications for patient management.

OBJECTIVE. Hydrogen peroxide (H 2 O 2 ) plays a key role in neutrophil oxidative defense against infection. Catalase-containing silica nanoshells are nanoparticles that generate O 2 microbubbles imaged with ultrasound in the presence of elevated H 2 O 2 . We aimed to determine whether ultrasound-detectable O 2 microbubbles produced by catalase-containing silica nanoshells can determine whether fluid collections drained from patients are infected. SUBJECTS AND METHODS. During this HIPAA-compliant, institutional review board-approved study, 52 human fluid samples were collected from clinically required image-guided percutaneous drainage procedures. Catalase-containing silica nanoshells were added to the fluid samples during imaging in real time using a Sequoia-512 15L8-S linear transducer (Siemens Healthcare). Production of detectable microbubbles was graded subjectively as negative (noninfected) or positive (infected) with low, moderate, or high confidence by a single observer blinded to all clinical data. The truth standard was microbiology laboratory culture results. Performance characteristics including ROC curves were calculated. RESULTS. Microbubble detection to distinguish infected from noninfected fluids was 84% sensitive and 72% specific and offered negative and positive predictive values of 89% and 64%, respectively. The AUC was 0.79. Six of nine false-positive samples were peritoneal fluid collections that were all collected from patients with decompensated cirrhosis. CONCLUSION. The presence of elevated H 2 O 2 indicated by microbubble formation in the presence of catalase-containing silica nanoshells is sensitive in distinguishing infected from noninfected fluids and offers a relatively high negative predictive value. False-positive cases may result from noninfectious oxidative stress. Catalase-containing silica nanoshells may constitute a novel point-of-care test performed at time of percutaneous drainage, potentially obviating placement of drains into otherwise sterile collections and minimizing risk of secondary infection or other complication.