Real-time contrast-enhanced ultrasound imaging of infected focal liver lesions

Washout on Contrast-Enhanced Ultrasound of Benign Focal Liver Lesions-A Review on Its Frequency and Possible Causes

In all imaging methods, including contrast-enhanced ultrasound (CEUS), enhancement in the late phase (LP) is an important criterion for differentiating between benign and malignant focal liver lesions (FLLs). In general, malignant liver lesions are characterized by hypoenhancement and washout in the LP. A lesion with LP hyperenhancement or isoenhancement in the non-cirrhotic liver is usually benign. However, LP hypoenhancement in benign lesions is not so rare, and is even normal and the standard for some lesions, and there are exceptions for each tumor entity that can represent a diagnostic challenge. Knowing these contrast patterns and exceptions is key for correct diagnosis and patient management. The following narrative review describes the contrast behaviors and the frequency of washout and LP hypoenhancement for common as well as rare benign liver lesions and analyzes its causes.

Contrast enhanced ultrasound of liver lesions in patients treated for childhood malignancies

BACKGROUND

Patients treated for cancer have a higher incidence of focal liver lesions than the general population and there is often concern for a malignant etiology. This can result in patient, caregiver and physician anxiety and is managed by a "wait and watch" approach, or immediate additional imaging, or biopsy, depending on the degree of clinical concern. Because it is a low-cost, easily accessible, radiation and sedation free modality, we investigated the value of contrast enhanced ultrasound (CEUS) to accurately distinguish benign from malignant liver lesions in patients treated for childhood malignancies.

METHODS

We performed an IRB approved retrospective study of 68 subjects who were newly diagnosed, on treatment or off treatment for a pediatric malignancy and had liver lesions discovered on CT, MRI or non-contrast ultrasound and subsequently underwent CEUS between September 2013 and September 2021. Two experienced pediatric radiologists and a radiology trainee, blinded to the etiology of the liver lesions, independently reviewed the CEUS examinations and categorized lesions as benign, indeterminate, or malignant. The reference standard was biopsy for 19 lesions and clinical follow-up for 49. The sensitivity, specificity, positive and negative predictive value, and diagnostic accuracy of CEUS were calculated using only the benign and malignant CEUS classifications. Inter-reviewer agreement was assessed by Cohen's kappa statistic.

RESULTS

There were 26 males and 42 females, mean age, 14.9 years (range, 1-52 years). Fifty subjects were off therapy, twelve receiving treatment, and six with newly diagnosed cancer. By the reference standard, 59 (87%) lesions were benign and 9 (13%) were malignant. Sensitivities of CEUS for the three reviewers ranged from 83 to 100% (95% CI, 35.9-100%), specificities from 93.1 to 96.0% (95% CI, 83.5-99.6%), PPV 60.0-71.4% (95% CI, 29.0-96.3%), NPV 98.0-100% (95% CI, 89.2-100%) and accuracy from 93.8 to 94.6% (95% CI, 85.1-99.7%). The kappa statistic for agreement between the two experienced radiologists was moderate at 0.58.

CONCLUSIONS

CEUS is highly accurate in distinguishing benign from malignant etiologies of liver lesions in patients treated for pediatric malignancies.

Granulomatous liver diseases

A granuloma is a discrete collection of activated macrophages and other inflammatory cells. Hepatic granulomas can be a manifestation of localized liver disease or be a part of a systemic process, usually infectious or autoimmune. A liver biopsy is required for the detection and evaluation of granulomatous liver diseases. The prevalence of granulomas on liver biopsy varies from 1% to 15%. They may be an incidental finding in an asymptomatic individual, or they may represent granulomatous hepatitis with potential to progress to liver failure, or in chronic disease, to cirrhosis. This review focuses on pathogenesis, histological features of granulomatous liver diseases, and most common etiologies, knowledge that is essential for timely diagnosis and intervention.

Utility of the pediatric liver contrast-enhanced ultrasound criteria in differentiating malignant and benign multifocal lesions

BACKGROUND

The pediatric liver contrast-enhanced ultrasound (CEUS) criteria were developed to improve the diagnostic performance of CEUS in differentiating pediatric benign and malignant liver lesions. However, the diagnostic performance of CEUS in the evaluation of multiple focal liver lesions in the pediatric population has not yet been fully evaluated.

OBJECTIVE

To evaluate the diagnostic performance of the pediatric liver CEUS criteria in differentiating benign and malignant multifocal liver lesions in children.

MATERIALS AND METHODS

From April 2017 to September 2022, the CEUS characteristics of multifocal liver lesions in patients < 18 years were analyzed. Lesions classified as CEUS-1, CEUS-2 or CEUS-3 were considered benign and lesions classified as CEUS-4 or CEUS-5 were considered malignant. The diagnostic performance of the pediatric liver CEUS criteria (i.e. sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV] and accuracy) was assessed.

RESULTS

After exclusion, 21 patients (median age, 36.0 months; range, 1.0-204 months; 7 boys) were included. There were significant differences in the serum alpha fetoprotein level (P= 0.039) and the presence of washout (P < 0.001) between children with malignant and benign lesions. The sensitivity, specificity, PPV, NPV and accuracy of the pediatric liver CEUS criteria were 100.0% (10/10), 90.9% (10/11), 90.9% (10/11), 100.0% (10/10) and 95.2% (20/21), respectively.

CONCLUSION

The pediatric liver CEUS criteria had excellent diagnostic performance in differentiating benign and malignant multifocal liver lesions in children.

Comparison of contrast-enhanced transabdominal ultrasonography following endoscopic ultrasonography with GD-EOB-DTPA-enhanced MRI for the sequential diagnosis of liver metastasis in patients with pancreatic cancer

PURPOSE

To compare contrast-enhanced transabdominal ultrasonography (CE-US) following contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) with enhanced magnetic resonance imaging using gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (EOB-MRI) in the diagnosis of liver metastases in patients with pancreatic cancer.

METHODS

Patients who underwent contrast-enhanced computed tomography for possible pancreatic cancer and required further evaluation with CH-EUS were enrolled in this study, and the diagnostic performance of CE-US following CH-EUS for liver metastasis was compared with that of EOB-MRI.

RESULTS

A total of 228 patients were included in the final analysis. Two hundred thirty-four hepatic lesions were found in 81 patients, and 178 lesions were finally diagnosed as metastases. EOB-MRI had a higher sensitivity (0.837 vs 0.949), while CE-US had a higher specificity and positive predictive value (PPV) (0.982 and 0.993 vs 0.911 and 0.971, respectively) in the diagnosis of liver metastasis. CE-US with defect reperfusion imaging had a higher diagnostic performance than EOB-MRI (0.866 vs 0.667) in the differentiation between liver metastasis and abscess.

CONCLUSION

EOB-MRI had a higher sensitivity than CE-US for diagnosing liver metastasis in patients with pancreatic cancer, but CE-US following CH-EUS demonstrated a higher specificity and PPV than EOB-MRI and was especially useful in the differentiation between liver metastasis and abscess.

Ultrasound and contrast-enhanced ultrasound (CEUS) in infective liver lesions

Infektiöse fokale Leberläsionen (FLL) treten in der klinischen Praxis häufig auf, wobei bakterielle Leberabszesse die Hälfte ausmachen. Eine genaue Diagnose der FLL ist für die Auswahl der am besten geeigneten Therapie und zur Vorbeugung von Komplikationen unerlässlich. Ziel der aktuellen Arbeit ist es, den Nutzen von Ultraschall und kontrastmittelverstärktem Ultraschall (CEUS) zur Erkennung und Charakterisierung infektiöser Leberläsionen zu beschreiben.

Differentiating infected focal liver lesions from malignant mimickers: value of ultrasound-based radiomics

AIM

To establish an ultrasound-based radiomics model through machine learning methods and then to assess the ability of the model to differentiate infected focal liver lesions from malignant mimickers.

MATERIALS AND METHODS

A total of 104 patients with infected focal liver lesions and 485 patients with malignant hepatic tumours were included, consisting of hepatocellular carcinoma (HCC), cholangiocarcinoma (CC), combined hepatocellular-cholangiocarcinoma (cHCC-CC), and liver metastasis. Radiomics features were extracted from grey-scale ultrasound images. Feature selection and predictive modelling were carried out by dimensionality reduction methods and classifiers. The diagnostic effect of the prediction mode was assessed by receiver operating characteristic (ROC) curve analysis.

RESULTS

In total, 5,234 radiomics features were extracted from grey-scale ultrasound image of every focal liver lesion. The ultrasound-based radiomics model had a favourable predictive value for differentiating infected focal liver lesions from malignant hepatic tumours, with an area under the curve (AUC) of 0.887 and 0.836 (HCC group), 0.896 and 0.766 (CC group), 0.944 and 0.754 (cHCC-CC group), 0.918 and 0.808 (liver metastasis group), and 0.949 and 0.745 (malignant hepatic tumour group) for the training set and validation set, respectively.

CONCLUSIONS

Ultrasound-based radiomics is helpful in differentiating infected focal liver lesions from malignant mimickers and has the potential for use as a supplement to conventional grey-scale ultrasound and contrast-enhanced ultrasound (CEUS).

Sonographic Features of Abscess Maturation in a Porcine Model

Abscesses are walled-off collections of infected fluids that often develop as complications in the setting of surgery and trauma. Treatment is usually limited to percutaneous catheterization with a course of antibiotics. As an alternative to current treatment strategies, a histotripsy approach was developed and tested in a novel porcine animal model. The goal of this article is to use advanced ultrasound imaging modes to extract sonographic features associated with the progression of abscess development in a porcine model. Intramuscular or subcutaneous injections of a bi-microbial bacteria mixture plus dextran particles as an irritant led to identifiable abscesses over a 2 to 3 wk period. Selected abscesses were imaged at least weekly with B-mode, 3-D B-mode, shear-wave elastography and plane-wave Doppler imaging. Mature abscesses were characterized by a well-defined core of varying echogenicity surrounded by a hypoechoic capsule that was highly vascularized on Doppler imaging. 3-D imaging demonstrated the natural history of abscess morphology, with the abscess becoming less complex in shape and increasing in volume. Furthermore, shear-wave elastography demonstrated variations in stiffness as phlegmon becomes abscess and then liquefies, over time. These ultrasound features potentially provide biomarkers to aid in selection of treatment strategies for abscesses.

Contrast-enhanced ultrasound of benign and malignant liver lesions in children

Contrast-enhanced ultrasound (CEUS) is increasingly being used in children. One of the most common referrals for CEUS performance is characterization of indeterminate focal liver lesions and follow-up of known liver lesions. In this setting, CEUS is performed with intravenous administration of ultrasound contrast agents (UCAs). When injected into a vein, UCA microbubbles remain confined within the vascular network until they dissipate. Therefore, visualization of UCA within the tissues and lesions corresponds to true blood flow. CEUS enables continuous, real-time observation of the enhancement pattern of a focal liver lesion, allowing in most cases for a definite diagnosis and obviating the need for further cross-sectional imaging or other interventional procedures. The recent approval of Lumason (Bracco Diagnostics, Monroe Township, NJ) for pediatric liver CEUS applications has spurred the widespread use of CEUS. In this review article we describe the role of CEUS in pediatric liver applications, focusing on the examination technique and interpretation of main imaging findings of the most commonly encountered benign and malignant focal liver lesions. We also compare the diagnostic performance of CEUS with other imaging modalities for accurate characterization of focal liver lesions.

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

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

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

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

Differential diagnosis between hepatic alveolar echinococcosis and intrahepatic cholangiocarcinoma with conventional ultrasound and contrast-enhanced ultrasound

BACKGROUND

Misclassifications of hepatic alveolar echinococcosis (HAE) as intrahepatic cholangiocarcinoma (ICC) may lead to inappropriate treatment strategies. The aim of this study was to explore the differential diagnosis with conventional ultrasound and contrast-enhanced ultrasound (CEUS).

METHODS

Sixty HAE lesions with 60 propensity score-matched ICC lesions were retrospectively collected. The 120 lesions were randomly divided into a training set (n = 80) and a testing set (n = 40). In the training set, the most useful independent conventional ultrasound and CEUS features was selected for differentiating between HAE and ICC. Then, a simplified US scoring system for diagnosing HAE was constructed based on selected features with weighted coefficients. The constructed US score for HAE was validated in both the training set and the testing set, and diagnostic performance was evaluated.

RESULTS

Compared with ICC lesions, HAE lesions were mostly located in the right lobe and had mixed echogenicity, a pseudocystic appearance and foci calcifications on conventional ultrasound. On CEUS, HAE lesions showed more regular rim-like enhancement than ICC lesions and had late washout with a long enhancement duration. The simplified US score consisted of echogenicity, pseudocystic/calcification, bile duct dilatation, enhancement pattern, enhancement duration, and marked washout. In the testing set, the sensitivity, specificity, LR+, LR- and the area under the ROC curve for the score to differentiate HAE from ICC were 80.0, 81.3%, 4.27, 0.25 and 0.905, respectively.

CONCLUSIONS

The US score based on typical features from both conventional ultrasound and CEUS could accurately differentiate HAE from ICC.

Contrast-Enhanced Ultrasound-Guided Interventions-The New Sheriff in Town?: A Case-Based Review of Problem Solving With Ultrasound Contrast

Ultrasound (US)-guided intervention is a well-established medical procedure and offers advantages such as real-time guidance, portability, reduced cost, shortened procedure time compared with computed tomography, and lack of ionizing radiation. Ultrasound contrast agents (UCAs) are a useful adjunct to US-guided procedures. The addition of microbubble UCAs during US-guided interventions can assist with biopsy planning and lesion selection, aid in identification of target lesions, and direct the biopsy toward viable tissue. Ultrasound contrast agents have been in use outside of the United States for many years and have been used off label at select institutions across the United States before the Food and Drug Administration approval of Lumason (Bracco Diagnostics) for liver lesion evaluation in April 2016. After Food and Drug Administration approval, the use of UCAs has expanded rapidly, and UCAs are being used for a variety of clinical applications. Ultrasound contrast agents have been shown to be safe, and there is no renal toxicity. In this article, we will discuss the indications and techniques for using contrast-enhanced ultrasound during US-guided interventions, and we will present case examples where contrast-enhanced ultrasound added value.

Contrast-Enhanced Ultrasound Features of Hepatic Reactive Lymphoid Hyperplasia: Correlation With Histopathologic Findings

OBJECTIVES

To find certain specifics of hepatic reactive lymphoid hyperplasia (HRLH) on contrast-enhanced ultrasound (CEUS) imaging as diagnostic imaging clues by retrospectively analyzing its enhancement features.

METHODS

From June 2010 to June 2017, 18 histopathologically confirmed HRLH lesions in 18 patients were included in this retrospective study. The lesion's location, maximum diameter, shape, margin, echogenicity, and color flow signal on conventional ultrasound (US) imaging and enhancement pattern, presence of a feeding artery, and donutlike enhancement on CEUS imaging were observed and recorded. The lesion size on CEUS imaging at peak enhancement and that on conventional US imaging were compared and recorded.

RESULTS

All of the lesions showed homogeneous hypoechogenicity with a regular well-defined margin on conventional US imaging, with a mean diameter ± SD of 14.3 ± 4.6 mm (range, 8-24 mm). On CEUS imaging, all of the lesions showed "quick-wash-in and quick-wash-out," which showed complete homogeneous hyperenhancement in the arterial phase and wash-out in the second half of the arterial phase or first half of the portal phase. In 83.3% (15 of 18) of the lesions, the lesion size that was enhanced at peak was enlarged compared with the hypoechoic area on conventional US imaging, and transient donutlike enhancement appeared when the lesion showed wash-out. In 55.6% (10 of 18) of cases, the feeding artery was detected.

CONCLUSIONS

Enlarged complete homogeneous hyperenhancement in the arterial phase, consequently followed by quick wash-out of the lesion and the appearance of donutlike enhancement, may be the CEUS features of HRLH.

Morphological and dynamic evaluation of complex cystic focal liver lesions by contrast-enhanced ultrasound: current state of the art

Complex cystic and cystic-like focal liver lesions (FLLs) encompass a spectrum of disorders ranging from non-neoplastic conditions to benign and malignant tumors. In this prospective, the possibility of non-invasive differentiation of these lesions is extremely important, because the clinical implications and therapeutic strategies vary considerably. Because of its advantageous cost/benefit ratio, widespread availability and easy execution, ultrasound (US) is the first-line imaging modality in most countries for the initial liver survey and represents the imaging technique that usually detects a complex liver cyst. However, US showed poor efficacy in the differential diagnosis of complex cystic FLLs. Thus, for years, computed tomography (CT) and magnetic resonance (MR) imaging have been used for further assessment of these lesions. Recently, the development of low mechanical index real-time contrast-enhanced ultrasound (CEUS) technique performed with the second generation of US contrast agents has led to an accurate depiction of macrovasculature and microvasculature. The technique yields information about contrast enhancement of the liver and FLLs almost as CT and MRI do, but in real time and without the use of ionizing radiation. To date, there is only a small amount of evidence about the role of CEUS in the less common setting of complex liver cysts. The aim of this review is to offer an up-to-date overview on the state of the art of CEUS in the study of the most common complex cystic focal liver lesions. To our knowledge, there are no literature comprehensive reviews on this topic.

[CEUS-diagnosis of benign liver lesions]

CLINICAL/METHODICAL ISSUE

Focal liver lesions are commonly seen during routine ultrasound examinations.

STANDARD RADIOLOGICAL METHODS

With native ultrasound there are lesions that cannot be sufficiently characterized. In these cases additional imaging might be necessary.

METHODICAL INNOVATIONS

With contrast-enhanced ultrasound (CEUS), focal liver lesions can be characterized with high diagnostic accuracy. After the ultrasound contrast agent has been injected into a peripheral vein, the examiner saves video loops of the arterial, portal venous and late contrast phases. Combing the findings of native and contrast-enhanced ultrasound allows not only assessment of the etiology as benign or malignant but also detailed characterization of the focal liver lesion in most cases.

PERFORMANCE

Using CEUS, focal liver lesions can be characterized with a sensitivity of over 95% and a specificity of about 83%.

ACHIEVEMENTS

The advantages of CEUS include that there is no radiation exposure and that the ultrasound contrast agent has no effects on the function of the liver, kidneys or the thyroid gland. The main limiting factors for CEUS are bowel gas and obesity of the patient.

PRACTICAL RECOMMENDATIONS

CEUS can visualize micro- and macrovascularization of benign focal liver lesions in real time. It is a useful imaging modality in unclear cases.

Comparison of Contrast-Enhanced Ultrasound and Positron Emission Tomography/Computed Tomography (PET/CT) in Lymphoma

Background

This study aimed to assess the value of contrast-enhanced ultrasound (CEUS) in the diagnosis and prognosis of lymphoma based on PET-CT.

Material/Methods

Our study included 88 superficial lymph nodes and 63 patients who underwent ultrasound-guided biopsy or surgery for pathology from October 2015 to March 2017. All lymph nodes were assessed by CEUS and PET-CT. CEUS and PET-CT parameters were recorded, including arrive time (AT), time to peak (TTP), base intensity (BI), peak intensity (PI), ascending slope (AS), descending slope (DS), area under the TIC curve (AUC), maximum standardized uptake value (SUVmax), and mean standardized uptake value (SUVmean). Pearson’s correlation was used to assess the associations of CEUS and PET-CT parameters.

Results

Of the 88 lymph nodes examined,12 were Hodgkin’s lymphoma (HL) and76 were non-Hodgkin’s lymphoma (NHL). The variations of CEUS dose parameters (ΔI, AUC, and AS) were positively correlated with PET-CT results (SUVmax and TLG). Correlation coefficients were 0.609, 0.518, 0.456, 0.630, 0.593, and 0. 532, respectively. The remaining time values (AT, TP, and ΔT) were negatively associated with PET-CT results. Correlation coefficients were −0.239, −0.272, −0.284and −0.377, −0.391, and −0.320, respectively.

Conclusions

Quantitative CEUS data were correlated with PET-CT values, with potential use in the diagnosis of lymphoma.

Contrast-Enhanced Ultrasound

Contrast-enhanced ultrasound imaging is a recently approved technique in the United States that uses a specific contrast agent, namely, microbubbles, consisting mainly of a gas core and a stabilized biological shell. These compounds allow for the visualization of small vascular beds and improve characterization of anatomic structures and lesions. They have a relatively safe profile and are primarily excreted through the lungs.

Contrast-enhanced ultrasound of benign liver lesions

Liver lesions are often incidentally detected on ultrasound examination and may be incompletely characterized, requiring further imaging. Contrast-enhanced ultrasound (CEUS) was recently approved by the Food and Drug Administration in the United States for liver lesion characterization. CEUS has the ability to characterize focal liver lesions and has been shown to be superior to color Doppler and power Doppler ultrasound in the detection of tumor vascularity. Differentiating benign from malignant liver lesions is essential to characterizing liver lesions. The CEUS imaging characteristics of benign liver lesions are reviewed, including hepatic cysts, hemangiomas, focal fat, focal nodular hyperplasia, hepatocellular adenomas, abscesses, and traumatic lesions.

Transient Segmental Enhancement of Pyogenic Liver Abscess: A Comparison Between Contrast-Enhanced Ultrasound and Computed Tomography

OBJECTIVE

This study aimed to investigate the correlation between the transient segmental enhancement (TSE) of liver abscesses on contrast-enhanced ultrasound (CEUS) imaging and contrast-enhanced computed tomography (CT) scans.

METHODS

In total, 42 abscesses in 38 patients were evaluated with real-time CEUS and contrast-enhanced CT imaging. The CT imaging and CEUS examinations were performed within one to 2 days of each other in all cases. The initial reports of the observations of TSE on CEUS scans were correlated later with the findings of TSE on contrast-enhanced CT images. Contrast-enhanced CT was used as the reference standard to evaluate the presence of TSE. Relationships between the 2 groups were analyzed using the χ test. P < 0.05 was considered to be statistically significant.

RESULTS

In 16 patients, 16 typical TSE signs were shown by CEUS. Meanwhile, enhanced CT imaging showed 18 typical signs of TSE in 17 patients. We identified 38 patients with hepatic abscesses proven by needle aspiration (10 patients) or image-guided biopsy (28 patients). Ten patients had hepatobiliary cholelithiasis, 5 had diabetes mellitus type 2, and 2 had gastric cancer, whereas no evidence of underlying hepatobiliary or gastrointestinal diseases was found in the other 21 patients. Considering that enhanced CT is the reference standard for the diagnosis of hepatic abscesses, the sensitivity of CEUS in showing TSE was 89%, and the specificity was 100%. The χ test indicated that CEUS and enhanced CT were significantly correlated for detection of hepatic perfusion disorders (P < 0.05).

CONCLUSIONS

The appearance of TSE in liver abscess was reliably detected by CEUS, which correlated well with the enhanced CT images (P < 0.05).

The role of CEUS in characterization of superficial lymph nodes: a single center prospective study

Accurate lymph node characterization is important in a large number of clinical settings. We evaluated the usefulness of Contrast Enhanced Ultrasound (CEUS) in distinguishing between benign and malignant lymph nodes compared with conventional ultrasonography in the differential diagnosis of superficial lymphadenopathy.

We present our experience for 111 patients enrolled in a single center.

111 superficial lymph nodes were selected and only 1 lymph node per patient underwent CEUS. A definitive diagnosis for all lymph nodes was obtained by ultrasonographically guided biopsy and/or excision biopsy.

The size of the lymph nodes, the site (neck, axilla, inguinal region) being easily accessible for biopsy, and the US and color Doppler US characteristics guided us in selecting the nodes to be evaluated by CEUS.

In our study we identified different enhancement patterns in benign and malignant lymph nodes, with a high degree of diagnostic accuracy for superficial lymphadenopathy in comparison with conventional US.

Liver Masses: What Physicians Need to Know About Ordering and Interpreting Liver Imaging

PURPOSE OF REVIEW

This paper reviews diagnostic imaging techniques used to characterize liver masses and the imaging characteristics of the most common liver masses.

RECENT FINDINGS

The role of recently adopted ultrasound and magnetic resonance imaging contrast agents will be emphasized. Contrast-enhanced ultrasound is an inexpensive exam which can confirm benignity of certain liver masses without ionizing radiation. Magnetic resonance imaging using hepatocyte-specific gadolinium-based contrast agents can help confirm or narrow the differential diagnosis of liver masses.

Hepatic Kaposi Sarcoma Revisited: An Important but Less Commonly Seen Neoplasm in Patients With Acquired Immunodeficiency Syndrome

Hepatic Kaposi sarcoma (KS) is the most commonly seen hepatic neoplasm in patients with acquired immunodeficiency syndrome (AIDS), found in 34% of patients in an autopsy series. However, the incidence of hepatic KS has significantly declined since the advent of highly active antiretroviral therapy and is not as commonly seen on imaging. We present a case of hepatic KS in a patient with AIDS, which was initially mistaken for hepatic abscesses on computed tomography. We discuss the computed tomography, grayscale ultrasound, and contrast-enhanced ultrasound appearance of hepatic KS and how to distinguish this hepatic neoplasm from other common hepatic lesions seen in patients with AIDS.

Modern role of clinical ultrasound in liver abscess and echinococcosis

In the Western world, liver abscesses are predominantly of pyogenic origin and can present a wide range of ultrasonographic features, from a solid mass to a cystic cavity. Amoebic abscesses are endemic in tropical areas and typically round single lesions. Echinococcal cyst is diagnosed by ultrasound (US). Serology is particularly useful when pathognomonic US features are absent. Treatment is determined based on the WHO ultrasonographic classification, and puncture, aspiration, injection, re-aspiration (PAIR) is a US-guided therapeutic option. Hepatic alveolar echinococcosis presents on US as a pseudotumoral mass frequently with calcifications that may invade the biliary tree and portal and hepatic veins.

Effect of contrast-enhanced ultrasound on differential diagnosis of intrahepatic cholangiocarcinoma and arterial phase enhanced hepatic inflammatory lesions

OBJECTIVE

To investigate differential diagnosis between intrahepatic cholangiocarcinoma (ICC) and arterial phase enhanced hepatic inflammatory lesions in patients without liver cirrhosis using contrast-enhanced ultrasound (CEUS).

METHODS

ICC and hepatic inflammatory lesions cases with CEUS and pathological diagnosis between Sep 2013 and Oct 2016 were investigated retrospectively. Imaging features of conventional ultrasound and CEUS were analyzed. The parameters of time intensity curve (TIC), including the arrival time, peak intensity (PI) in the lesions, the starting time for washout, and the intensity difference at 3 min (ΔI3) after contrast agent infection between the lesion and the liver parenchyma, were compared between ICC and hepatic inflammatory lesions.

RESULTS

Twenty-five ICC and fifteen inflammatory patients were included in this study. Seventeen ICC (68.0%) and two inflammatory cases (13.3%) showed bile duct dilatation on conventional ultrasound. Using CEUS, three ICC cases (12.0%) were misdiagnosed as inflammatory lesions and three inflammatory lesions (20.0%) as ICC; two ICC (8.0%) and one inflammatory case (6.7%) could not be made definite diagnosis. Washout started at 34.5±3.5 s and 61.5±12.9 s for ICC and inflammatory lesions respectively (P<0.001). The intensity difference between lesion and liver parenchyma at 3 min after contrast agent injection was 10.8±3.1 dB in ICC and 4.2±2.3 dB in inflammatory group (P<0.001). The sensitivity and specificity differentiating ICC and inflammatory lesions were 76% and 87% if the cut-off value of the intensity difference was 7.7 dB.

CONCLUSIONS

Combined with TIC analysis, and particularly with the characteristic of the early-starting and obvious washout in ICC, CEUS can be useful in differential diagnosis between hepatic inflammatory lesions and ICC.

Contrast-enhanced US-guided Interventions: Improving Success Rate and Avoiding Complications Using US Contrast Agents

Ultrasonography (US) is an established modality for intervention. The introduction of microbubble US contrast agents (UCAs) has the potential to further improve US imaging for intervention. According to licensing, UCAs are currently approved for clinical use in restricted situations, but many additional indications have become accepted as having clinical value. The use of UCAs has been shown to be safe, and there is no risk of renal toxic effects, unlike with iodinated or gadolinium contrast medium. Broadly speaking, UCAs can be injected into the bloodstream (intravascular use) or instilled into almost any accessible body cavity (endocavitary use), either in isolation or synchronously. In microvascular applications, contrast-enhanced US (CEUS) enhances delineation of necrotic areas and the vascularized target to improve real-time targeting. The ability of CEUS to allow true assessment of vascularity has also been used in follow-up of devascularizing intervention. In macrovascular applications, real-time angiographic images can be obtained with CEUS without nephrotoxic effects or radiation. In endocavitary applications, CEUS can achieve imaging similar to that of iodinated contrast medium-based fluoroscopy; follow-up to intervention (eg, tubography and nephrostography) can be performed at the bedside, which may be advantageous. The use of UCAs is a natural progression in US-guided intervention. The aim of this article is to describe the indications, contraindications, and techniques of using UCAs as an adjunctive tool for US-guided interventional procedures to facilitate effective treatment, improve complication management, and increase the overall success of interventional procedures. Online supplemental material is available for this article. ^©RSNA, 2016.

Contrast-Enhanced Ultrasound in Focal Liver Lesions: Where Do We Stand?

Contrast-enhanced ultrasound (CEUS) represents a significant breakthrough in sonography, and it is being increasingly used for the evaluation of focal liver lesions (FLLs). Currently, CEUS is included as a part of the suggested diagnostic workup of FLLs, resulting in a better patient management and delivering cost-effective therapy. After a brief technical note, contrast-enhancement patterns of different types of benign and malignant FLLs, along with hepatic pseudolesions, are described and discussed based on our experience and literature data. At the same time, the most recent concepts and the use of CEUS in different clinical settings are presented.

The Evolving Nature of Hepatic Abscess: A Review

Hepatic abscess (HA) remains a serious and often difficult to diagnose problem. HAs can be divided into three main categories based on the underlying conditions: infectious, malignant, and iatrogenic. Infectious abscesses include those secondary to direct extension from local infection, systemic bacteremia, and intra-abdominal infections that seed the portal system. However, over the years, the etiologies and risks factors for HA have continued to evolve. Prompt recognition is important for instituting effective management and obtaining good outcomes.

Focal Lesions in Fatty Liver: If Quantitative Analysis Facilitates the Differentiation of Atypical Benign from Malignant Lesions

To evaluate the diagnostic performance of quantitative analysis as an adjunctive diagnostic tool to contrast-enhanced ultrasound (US) for the differentiation of atypical benign focal liver lesions (FLLs) from malignancies in fatty liver. Twenty-seven benign FLLs and fifty-six malignant FLLs that appeared hyper-enhanced during the arterial phase with washout in the portal or late phase in fatty liver were analyzed. Chi-square tests and logistic regression were applied to identify the specific features. Three sets of criteria were assigned: 1) all FLLs subjected to routine contrast-enhanced US; 2) all FLLs subjected to quantification analysis and contrast-enhanced US; and 3) parts of FLLs that could not be diagnosed using contrast-enhanced US (n = 66, 75.9%) but instead were diagnosed using parametric features. The sensitivity, specificity, accuracy and area under the receiver operating characteristic curve (AUC) of the three sets of criteria were analyzed. The AUCs of the criterion set 2 were significantly higher than those of criterion set 1 (0.904 versus 0.792, P = 0.008). Criterion set 3 showed a relatively high sensitivity (90.2%) with a relatively high AUC (0.845). The quantification analysis offers improved diagnostic performance for the differential identification of atypical benign FLLs from malignancies in fatty liver.

Imaging findings of mimickers of hepatocellular carcinoma

Radiological imaging plays a crucial role in the diagnosis of hepatocellular carcinoma (HCC) as the noninvasive diagnosis of HCC in high-risk patients by typical imaging findings alone is widely adopted in major practice guidelines for HCC. While imaging techniques have markedly improved in detecting small liver lesions, they often detect incidental benign liver lesions and non-hepatocellular malignancy that can be misdiagnosed as HCC. The most common mimicker of HCC in cirrhotic liver is nontumorous arterioportal shunts that are seen as focal hypervascular liver lesions on dynamic contrast-enhanced cross-sectional imaging. Rapidly enhancing hemangiomas can be easily misdiagnosed as HCC especially on MR imaging with liver-specific contrast agent. Focal inflammatory liver lesions mimic HCC by demonstrating arterial-phase hypervascularity and subsequent washout on dynamic contrast-enhanced imaging. It is important to recognize the suggestive imaging findings for intrahepatic cholangiocarcinoma (CC) as the management of CC is largely different from that of HCC. There are other benign mimickers of HCC such as angiomyolipomas and focal nodular hyperplasia-like nodules. Recognition of their typical imaging findings can reduce false-positive HCC diagnosis.

Vascular phases in imaging and their role in focal liver lesions assessment

The incidental finding of a liver lesion with basic ultrasound is one of the most common clinical issues. Some of the liver lesions which present typical morphological B-mode features (e.g. cysts, typically localized focal fatty sparing/accumulations, hyperechoic hemangiomas) can be easily diagnosed by conventional ultrasound without the need of further diagnostic procedures. Others frequently necessitate further investigation with contrast-enhanced imaging techniques or biopsy in order to differentiate benign from malignant lesions and obtain a final diagnosis. This paper will discuss differences between vascular phases of different cross-sectional contrast-enhanced methods, as well as their subsequent benefits for focal liver lesions (FLLs) assessment, adding also a particular emphasis on small FLLs detection and characterization.

Contrast-enhanced ultrasound in different stages of pyogenic liver abscess

To enable sonographic classification of different stages of pyogenic liver abscesses, sonographic findings in 86 patients with 113 pyogenic liver abscesses were retrospectively analyzed and compared with established pathomorphologic descriptions of the disease. The typical findings in contrast-enhanced ultrasound were sub-segmental hyperemia (93/113, 82%) and necrosis with a hyperemic margin (109/113, 96%) in the arterial phase and a washout of liver tissue surrounding necrosis in the late phase (101/113, 89%). Four different sonomorphologic stages of pyogenic liver abscess were identified. Stage I was defined by focal inflammation without necrosis (n = 2); stage II by focal clusters of micro-abscesses appearing to coalesce (n = 41); and stage III by a single cavity with or without capsule (n = 64). Stage IV was defined as numerous small abscesses scattered all over the liver (n = 6). The results indicate that contrast-enhanced ultrasound is suitable for classifying different stages of pyogenic liver abscesses. Knowledge of the described morphologic patterns influences therapeutic decisions and helps distinguish abscesses from other liver masses.

Benign liver lesions: grey-scale and contrast-enhanced ultrasound appearances

Ultrasound is often the first point of detection of liver lesions, with up to 75% of liver lesions detected at ultrasound having benign histology. In 2012, NICE issued recommendations that ultrasound contrast be used for the evaluation of incidentally discovered liver lesions. This has been demonstrated to provide a rapid and cost-effective evaluation for incidental liver lesions, in many cases precluding the need for further CT or MRI scans. The aim of this review is to demonstrate the ultrasound features of benign liver lesions, and to demonstrate their further characterisation with contrast ultrasound.

Usefulness of contrast-enhanced ultrasound with Sonazoid for evaluating liver abscess in comparison with conventional B-mode ultrasound

AIM

The purpose of this study was to evaluate the usefulness of contrast-enhanced ultrasound (CEUS) with Sonazoid (perfluorobutane) in patients with liver abscess. Sonazoid is a contrast agent with a low mechanical index and is phagocytosed by Kupffer cells.

METHODS

Twenty-two patients with liver abscess were evaluated with conventional US, real-time CEUS with Sonazoid, and enhanced computed tomography (CT). After 0.5 mL of Sonazoid was administrated i.v., CEUS images in the vascular and post-vascular phases were observed.

RESULTS

Conventional US showed hypoechoic lesions in 13 (59.1%), isoechoic in four (18.2%), hyperechoic in two (9.1%), mixed echoic in two (9.1%) and undetected in one (4.8%) patient. CEUS showed perilesional enhancement in 19 (86.4%) lesions in the vascular phase and well-defined unenhanced areas in 22 (100%) lesions in the post-vascular phase. CEUS revealed that 18 abscesses were cystic type and three were honeycomb type. Twenty-one abscesses (95.5%) had clearer appearances on CEUS than on conventional US in regard to the extent of necrotic or liquefied lesions seen. We could confirm reduction of the lesions after therapy in 13 (92.9%) of 14 patients followed up by CEUS.

CONCLUSION

Most of the liver abscesses showed perilesional enhancement in the vascular phase and unenhanced areas in the post-vascular phase. The appearance of liver abscesses was clearer on CEUS than on conventional US. CEUS with Sonazoid can be a more effective diagnostic and therapeutic tool for liver abscess.

Percutaneous drainage of abdominal and pelvic abscesses in children

It has only been in the last several decades that abscesses within deep compartments, particularly within the abdomen and pelvis, have become safely accessible with imaging guidance. Since that time, percutaneous abscess drainage has become the standard of care in children. We review the clinical features, diagnosis, and image-guided management of abdominal and pelvic abscesses in children.

Guidelines and good clinical practice recommendations for Contrast Enhanced Ultrasound (CEUS) in the liver - update 2012: A WFUMB-EFSUMB initiative in cooperation with representatives of AFSUMB, AIUM, ASUM, FLAUS and ICUS

Initially, a set of guidelines for the use of ultrasound contrast agents was published in 2004 dealing only with liver applications. A second edition of the guidelines in 2008 reflected changes in the available contrast agents and updated the guidelines for the liver, as well as implementing some non-liver applications. Time has moved on, and the need for international guidelines on the use of CEUS in the liver has become apparent. The present document describes the third iteration of recommendations for the hepatic use of contrast enhanced ultrasound (CEUS) using contrast specific imaging techniques. This joint WFUMB-EFSUMB initiative has implicated experts from major leading ultrasound societies worldwide. These liver CEUS guidelines are simultaneously published in the official journals of both organizing federations (i.e., Ultrasound in Medicine and Biology for WFUMB and Ultraschall in der Medizin/European Journal of Ultrasound for EFSUMB). These guidelines and recommendations provide general advice on the use of all currently clinically available ultrasound contrast agents (UCA). They are intended to create standard protocols for the use and administration of UCA in liver applications on an international basis and improve the management of patients worldwide.

Contrast agent-free sonoporation: The use of an ultrasonic standing wave microfluidic system for the delivery of pharmaceutical agents

Sonoporation is a useful biophysical mechanism for facilitating the transmembrane delivery of therapeutic agents from the extracellular to the intracellular milieu. Conventionally, sonoporation is carried out in the presence of ultrasound contrast agents, which are known to greatly enhance transient poration of biological cell membranes. However, in vivo contrast agents have been observed to induce capillary rupture and haemorrhage due to endothelial cell damage and to greatly increase the potential for cell lysis in vitro. Here, we demonstrate sonoporation of cardiac myoblasts in the absence of contrast agent (CA-free sonoporation) using a low-cost ultrasound-microfluidic device. Within this device an ultrasonic standing wave was generated, allowing control over the position of the cells and the strength of the acoustic radiation forces. Real-time single-cell analysis and retrospective post-sonication analysis of insonated cardiac myoblasts showed that CA-free sonoporation induced transmembrane transfer of fluorescent probes (CMFDA and FITC-dextran) and that different mechanisms potentially contribute to membrane poration in the presence of an ultrasonic wave. Additionally, to the best of our knowledge, we have shown for the first time that sonoporation induces increased cell cytotoxicity as a consequence of CA-free ultrasound-facilitated uptake of pharmaceutical agents (doxorubicin, luteolin, and apigenin). The US-microfluidic device designed here provides an in vitro alternative to expensive and controversial in vivo models used for early stage drug discovery, and drug delivery programs and toxicity measurements.

Evaluation of focal hepatic lesions with ultrasound contrast agents

Ultrasound contrast agents have gained wide acceptance for the detection and characterization of focal liver lesions. This pictorial essay reviews the growing body of evidence that supports the use of modern ultrasound contrast agents and illustrates the enhancement characteristics of commonly encountered focal liver lesions. Pathologies discussed include metastases, hepatocellular carcinomas, focal nodular hyperplasia, hepatocellular adenomas, hemangiomas, abscesses, complex cysts, and focal fatty deposition.

Differentiation of focal liver lesions: usefulness of parametric imaging with contrast-enhanced US

PURPOSE

To evaluate whether parametric imaging with contrast material-enhanced ultrasonography (US) is superior to visual assessment for the differential diagnosis of focal liver lesions (FLLs).

MATERIALS AND METHODS

This study had institutional review board approval, and verbal patient informed consent was obtained. Between August 2005 and October 2008, 146 FLLs in 145 patients (63 women, 82 men; mean age, 62.5 years; age range, 22-89 years) were imaged with real-time low-mechanical-index contrast-enhanced US after a bolus injection of 2.4 mL of a second-generation contrast agent. Clips showing contrast agent uptake kinetics (including arterial, portal, and late phases) were recorded and subsequently analyzed off-line with dedicated image processing software. Analysis of the dynamic vascular patterns (DVPs) of lesions with respect to adjacent parenchyma allowed mapping DVP signatures on a single parametric image. Cine loops of contrast-enhanced US and results from parametric imaging of DVP were assessed separately by three independent off-site readers who classified each lesion as benign, malignant, or indeterminate. Sensitivity, specificity, accuracy, and positive and negative predictive values were calculated for both techniques. Interobserver agreement (κ statistics) was determined.

RESULTS

Sensitivities for visual interpretation of cine loops for the three readers were 85.0%, 77.9%, and 87.6%, which improved significantly to 96.5%, 97.3%, and 96.5% for parametric imaging, respectively (P < .05, McNemar test), while retaining high specificity (90.9% for all three readers). Accuracy scores of parametric imaging were higher than those of conventional contrast-enhanced US for all three readers (P < .001, McNemar test). Interobserver agreement increased with DVP parametric imaging compared with conventional contrast-enhanced US (change of κ from 0.54 to 0.99).

CONCLUSION

Parametric imaging of DVP improves diagnostic performance of contrast-enhanced US in the differentiation between malignant and benign FLLs; it also provides excellent interobserver agreement.

Contrast-enhanced ultrasound of the spleen: an introduction and pictorial essay

A wide variety of pathologies can produce focal lesions within the spleen. These are being more frequently encountered as imaging technology improves. It is vital that radiologists are aware of these pathologies to enable accurate diagnosis. The role of ultrasound contrast in splenic disease will be discussed and illustrated with cases likely to be encountered by general and abdominal radiologists.

The nodular form of hepatic tuberculosis: contrast-enhanced ultrasonographic findings with pathologic correlation

OBJECTIVE

The purposes of this study were to describe the ultrasonographic findings in hepatic tuberculosis (TB) after administration of a second-generation sulfur hexafluoride-filled microbubble contrast agent and to correlate these findings with pathologic characteristics.

METHODS

Twenty-four hepatic TB lesions in 15 patients were studied with conventional ultrasonography (CUS) and contrast-enhanced ultrasonography (CEUS). Pathologic characteristics of the lesions were evaluated and were then correlated with enhancement patterns.

RESULTS

The appearance of hepatic TB on CUS was variable and nonspecific with respect to the shape, echogenicity, and boundary of the lesions. The diameters of the lesions obtained from CEUS were statistically larger than those from CUS, with largest diameters +/- SD of 4.2 +/- 1.8 and 3.1 +/- 1.9 cm, respectively. During the arterial phase, 13 of 24 lesions (54.2%) showed a rapidly and markedly enhanced rim with a hypoenhanced or nonenhanced center; 9 of 24 lesions (37.5%) showed transient enhancement of the whole lesion with inconsistent intensities. During the portal phase, most lesions showed distinct wash-out of the contrast agent and maintained a hypoechoic appearance. Pathologic studies confirmed that the different appearances of hepatic TB on CEUS were related to the different pathologic stages of the lesions.

CONCLUSIONS

Findings of hepatic TB on CEUS may be helpful in differentiating the diagnosis from other hepatic focal lesions. Correlation with pathologic findings would enrich the understanding of CEUS findings in hepatic TB.

Hypervascular liver masses on contrast-enhanced ultrasound: the importance of washout

OBJECTIVE

The objective of our study was to determine the role of negative enhancement (washout), its presence and timing, in the differential diagnosis of hypervascular liver masses on contrast-enhanced ultrasound.

MATERIALS AND METHODS

One-hundred forty-six hypervascular liver lesions (mean size, 3.9 cm; range, 1.0-17.0 cm) were evaluated with contrast-enhanced ultrasound over a 6-month period. Seventy-four were benign (29 hemangiomas, 31 focal nodular hyperplasia [FNH] lesions, seven adenomas, five inflammatory lesions, two other) and 72, malignant (41 hepatocellular carcinomas [HCCs], 25 metastases, six other). Two independent reviewers retrospectively recorded the presence and timing of washout in the portal venous phase, observing until 4 minutes after injection, of a contrast agent (perflutren microspheres). Diagnoses were confirmed by histopathology (n = 68) or clinicoradiologic follow-up (n = 78). Timing of washout was compared between types of lesion using Fisher's exact test.

RESULTS

Washout occurred in both benign (27/74, 36%) and malignant (70/72, 97%) lesions but was more frequently seen in malignancy (p < 0.001) (kappa = 0.91). Metastases showed more rapid washout than HCCs (p < 0.001): 20 of 25 metastases showed washout by 30 seconds after injection and 23 of 41 HCCs, later than 75 seconds. All malignant lesions without washout were HCCs (2/41). Among the benign lesions, all five inflammatory lesions showed rapid washout before 75 seconds and six of seven adenomas showed washout, mostly later than 75 seconds (5/6). Washout also occurred in hemangiomas (6/29) and FNH lesions (9/31), mostly later than 75 seconds after injection (12/15).

CONCLUSION

Hypervascular malignant lesions show washout except infrequent cases of HCC. Rapid washout characterizes metastases, whereas HCCs show variable, often slow, washout. However, washout is not unique to malignancy and may be seen in benign lesions.

Clinical application of contrast-enhanced ultrasonography in diagnosis of superficial lymphadenopathy

OBJECTIVE

The purpose of this study was to evaluate the value of contrast-enhanced ultrasonography (CEUS) in differential diagnosis of superficial lymphadenopathy.

METHODS

Ninety-four superficial enlarged lymph nodes in 94 patients were studied by conventional ultrasonography (gray scale and color Doppler) and CEUS. Contrast-enhanced sonograms were analyzed using contrast-specific quantification software. All of the results were compared with pathologic diagnoses.

RESULTS

Of the 94 lymph nodes examined, 44 were benign and 50 were malignant (33 metastases and 17 lymphomas). The sensitivity, specificity, and accuracy of conventional ultrasonography in differential diagnosis between benign and malignant nodes were 51%, 47%, and 55%, respectively. Contrast-enhanced ultrasonography showed intense homogeneous enhancement in 39 of 44 benign lymph nodes, inhomogeneous enhancement in 32 of 33 metastases, and intense homogeneous enhancement and absence of perfusion in 9 of 17 and 6 of 17 lymphomas, respectively. The sensitivity specificity, and accuracy of CEUS were 84%, 79%, and 80%. After time-intensity curve gamma variates were calculated, the area under the curve of the benign lymph nodes was greater than those of the metastatic lymph nodes and lymphomas (P < .01).

CONCLUSIONS

These results indicate that the use of CEUS and contrast-specific software has a higher degree of diagnostic accuracy than conventional ultrasonography for evaluations of superficial lymphadenopathy. The contrast enhancement patterns and time-intensity curves provide valuable diagnostic information for differential diagnosis of benign and malignant lymph nodes.