Contrast-Enhanced Ultrasound of Focal Liver Lesions

Focal lesions of the liver: imaging appearances and management

With the increasing use of cross-sectional imaging, the detection of incidental liver lesions has become more common. Accurate and reliable characterisation of these is vital for optimal patient care. Owing to the great improvements in medical imaging technology in recent years, particularly magnetic resonance imaging, it is now possible to characterise a significant proportion of these non-invasively. This is of paramount importance in improving patient safety and reducing costs by avoiding unnecessary biopsies. This article gives a synopsis of the different imaging modalities for liver. It depicts the salient imaging features of the common benign and malignant focal liver lesions on different imaging modalities, with emphasis on magnetic resonance imaging. It demonstrates the pseudolesions, variants, mimics and pitfalls that occur in liver imaging. The tailored magnetic resonance imaging protocols including abbreviated ones, the contrast agents and the pathway for managing incidental liver lesions in the author's institution are covered.

Contrast-enhanced ultrasound imaging of the liver: a review of the clinical evidence for SonoVue and Sonazoid

Contrast-enhanced ultrasound (CEUS) has become an established modality in various clinical indications for liver diseases. SonoVue^®, a pure blood pure agent, and Sonazoid^®, which exhibits an additional Kupffer phase, are contrast agents approved for liver imaging. This review discusses and compares the current clinical evidence for these two ultrasound contrast agents in the characterization and detection of focal liver lesions in the non-cirrhotic and cirrhotic liver, as well as for the use in interventional procedures such as liver biopsy guidance, and local ablation treatment monitoring. Reference is made to clinical studies which evaluated the accuracy of CEUS using a standard of reference, its safety, or to comparative studies of these two agents.

ACR Appropriateness Criteria® Liver Lesion-Initial Characterization

Incidental liver masses are commonly identified on imaging performed for other indications. Since the prevalence of benign focal liver lesions in adults is high, even in patients with primary malignancy, accurate characterization of incidentally detected lesions is of paramount clinical importance. This document reviews utilization of various imaging modalities for characterization of incidentally detected liver lesions, discussed in the context of several clinical scenarios. For each clinical scenario, a summary of current evidence supporting the use of a given diagnostic modality is reported. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Comparison of Super-Resolution US and Contrast Material-enhanced US in Detection of the Spoke Wheel Sign in Patients with Focal Nodular Hyperplasia

Background Diagnosis of focal nodular hyperplasia (FNH) with US generally requires the use of contrast material. The effect of the super-resolution US technique on the diagnosis of FNH is unknown. Purpose To investigate the equivalence between super-resolution US and contrast material-enhanced US in the detection of spoke wheel sign in patients with FNH by comparing patterns of tumor vascularity. Materials and Methods This is a secondary analysis of a prospective trial (NCT02737865) that enrolled participants diagnosed with FNH between May 2016 and March 2019. These patients underwent super-resolution US and subsequent contrast-enhanced US with perfluorobutane microbubbles on the same day. The primary outcome was the confidence score of detecting spoke wheel sign in patients with FNH at US. Two radiologists used a four-point scale to score their confidence in the presence of the spoke wheel sign based on super-resolution US and contrast-enhanced US findings. Two one-sided tests were used to test the equivalence between super-resolution US and contrast-enhanced US in terms of the score for the confidence level of the spoke wheel sign. Interobserver agreement for both techniques between the two radiologists, using the recorded images, was analyzed by using an intraclass correlation coefficient. Results In 62 patients (mean age, 37 years; range, 20-69 years; 41 women) with FNH, the majority of patients showed a spoke wheel sign at super-resolution US and contrast-enhanced US (63% [39 of 62] and 71% [44 of 62], respectively; P = .36). There was no significant difference between the super-resolution US and contrast-enhanced US techniques regarding the confidence score for the spoke wheel sign (mean score, 1.8 vs 2.0; P = .03 for equivalence test). The intraclass correlation coefficients of super-resolution US and contrast-enhanced US regarding the presence of the spoke wheel sign were 0.82 (95% confidence interval: 0.73, 0.96) and 0.58 (95% confidence interval: 0.41, 0.73), respectively. Conclusion In comparison with contrast-enhanced US, super-resolution US provided a reliable rate of detection of the spoke wheel sign in patients with focal nodular hyperplasia. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Fetzer in this issue.

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.

The Echogenic Liver: Steatosis and Beyond

ABSTRACT

Ultrasound is the most common modality used to evaluate the liver. An echogenic liver is defined as increased echogenicity of the liver parenchyma compared with the renal cortex. The prevalence of echogenic liver is approximately 13% to 20%. In most clinical settings, increased liver echogenicity is simply attributed to hepatic steatosis. It is important to recognize other hepatic and systemic diseases including cirrhosis, viral hepatitis, glycogen storage disease, and hemochromatosis that may also cause an echogenic liver and to identify the associated findings to distinguish them from hepatic steatosis.

Contrast-Enhanced Ultrasound for Focal Hepatic Lesions: When to Use and How to Differentiate Lesions?

Contrast-enhanced ultrasound can be used effectively to evaluate focal hepatic lesions and offers unique advantages over computed tomography and magnetic resonance imaging. Serial vascular filling patterns of focal hepatic lesions during arterial, portal, and late phases can provide unique information on lesion characterization and differentiation. Sensitive depiction of arterial hypervascularity and analysis of washout pattern are clues for differentiation of several indeterminate hepatic nodules on conventional ultrasound and computed tomography/magnetic resonance. In this report, we present cases demonstrating clinical applications of contrast-enhanced ultrasound in the diagnosis and management of focal hepatic lesions.

Diagnostic Value of High Frame Rate Contrast-enhanced Ultrasonography and Post-processing Contrast Vector Imaging for Evaluation of Focal Liver Lesions: A Feasibility Study

This study evaluated the feasibility of contrast vector imaging (CVI) to characterize focal liver lesions. From July to October 2019, we prospectively enrolled 30 patients with focal liver lesions (hepatocellular carcinoma [HCC] [n = 19], metastasis [n = 8], combined HCC-cholangiocarcinoma [CC] [n = 1], intra-hepatic CC [n = 1] and sclerosed hemangioma [n = 1]). Contrast-enhanced ultrasound (CEUS) was performed with high frame rate contrast harmonic imaging technique by one radiologist, and post-processing CVI was obtained and analyzed by two radiologists. On combined CVI with CEUS, the staining pattern was significantly predominant in HCCs (9/11, 81.8%), while peripheral rim was frequent in non-HCCs (5/8, 62.5%) (p = 0.020). HCCs exhibited feeding arteries (8/11, 45.5%) and high velocity variance (10/11, 90.9 %), whereas non-HCCs showed detour pattern (4/8, 50.0%) with either a high or low velocity variance (4/8, 50.0%, both), with no significant inter-group differences (p = 0.052 and 0.080, respectively). In conclusion, CVI was feasible and provided quantitative and multi-parametric information of different types of hepatic tumors.

Microvascular Flow Imaging of Residual or Recurrent Hepatocellular Carcinoma after Transarterial Chemoembolization: Comparison with Color/Power Doppler Imaging

Objective

To determine the feasibility of microvascular flow imaging (MVFI) in comparison with color/power Doppler imaging (CDI/PDI) for detection of intratumoral vascularity in suspected post-transarterial chemoembolization (TACE) residual or recurrent hepatocellular carcinomas (HCCs) by using contrast-enhanced ultrasonography (CEUS) or hepatic angiography (HA) findings as the reference standard.

Materials and Methods

One hundred HCCs (mean size, 2.2 cm) in 100 patients treated with TACE were included in this prospective study. CDI, PDI, and MVFI were performed in tandem for evaluating intratumoral vascularity of the lesions by using an RS85 ultrasound scanner (Samsung Medison Co., Ltd.). Intratumoral vascularity in each technique was assessed by two radiologists in consensus by using a 5-point scale. Then, one of the two radiologists and another radiologist performed additional image review in the reverse order (MVFI-PDI-CDI) for evaluation of intra- and interobserver agreements. Results were then compared with those of either HA or CEUS as the reference. The McNemar test, logistic regression analysis, and intraclass correlation coefficient (ICC) were used.

Results

CEUS or HA revealed intratumoral vascularity in 87% (87/100) of the tumors. Sensitivity (79.3%, 69/87) and accuracy (80.0%, 80/100) of MVFI were significantly higher than those of CDI (sensitivity, 27.6% [24/87]; accuracy, 37.0% [37/100]) or PDI (sensitivity, 36.8% [32/87]; accuracy, 44.0% [44/100]) (all p < 0.05). CDI, PDI, and MVFI presented excellent intraobserver (ICCs > 0.9) and good interobserver agreements (ICCs > 0.6).

Conclusion

MVFI demonstrated significantly higher sensitivity and accuracy than did CDI and PDI for the detection of intratumoral vascularity in suspected residual or recurrent HCCs after TACE.

Diagnostic approach in hepatic lymphoma: radiological imaging findings and literature review

PURPOSE

Imaging manifestations of hepatic lymphoma, both primary (PHL) and secondary (SHL), are extremely variable and non-specific, but some features are useful diagnostic clues in an appropriate clinical setting. Through a PubMed search, we found several published reviews focused on PHL and SHL diagnosis. However, to the best of our knowledge, few of them encompass a comprehensive analysis of all the diagnostic tools and relative radiological findings. The aim of this review is to provide a description of the radiological features of both PHL and SHL, by critically analyzing the available literature.

MATERIALS AND METHODS

An extensive review of published literature along with a description of personal case series of both PHL and SHL has been conducted.

RESULTS

SHL can be easily diagnosed with imaging techniques, as it is usually associated with node disease. On the contrary the diagnosis can be a challenge in PHL, often mimicking HCC or liver metastasis of adenocarcinoma. In this context, multiparametric MRI plays a fundamental role in the differential diagnosis. Both for PHL and SHL, liver involvement presents as solitary or multiple lesions or as diffuse infiltrative disease.

CONCLUSION

PHL and SHL may be correctly characterized using different radiological techniques. Both CT and MRI have showed a good correlation with histology, as they permit to distinguish between lymphomatous tissue, and necrotic and fibrotic areas.

Anti-G250 nanobody-functionalized nanobubbles targeting renal cell carcinoma cells for ultrasound molecular imaging

Traditional imaging examinations have difficulty in identifying benign and malignant changes in renal masses. This difficulty may be solved by ultrasound molecular imaging based on targeted nanobubbles, which could specifically enhance the ultrasound imaging of renal cell carcinomas (RCC) so as to discriminate benign and malignant renal masses. In this study, we aimed to prepare anti-G250 nanobody-functionalized targeted nanobubbles (anti-G250 NTNs) by coupling anti-G250 nanobodies to lipid nanobubbles and to verify their target specificity and binding ability to RCC cells that express G250 antigen and their capacity to enhance ultrasound imaging of RCC xenografts. Anti-G250 nanobodies were coupled to the lipid nanobubbles using the biotin-streptavidin bridge method. The average particle diameter of the prepared anti-G250 NTNs was 446 nm. Immunofluorescence confirmed that anti-G250 nanobodies were uniformly distributed on the surfaces of nanobubbles. In vitro experiments showed that the anti-G250 NTNs specifically bound to G250-positive 786-O cells and HeLa cells with affinities of 88.13% ± 4.37% and 71.8% ± 5.7%, respectively, and that they did not bind to G250-negative ACHN cells. The anti-G250 NTNs could significantly enhance the ultrasound imaging of xenograft tumors arising from 786-O cells and HeLa cells compared with blank nanobubbles, while the enhancement was not significant for xenograft tumors arising from ACHN cells. Immunofluorescence of tumor tissue slices confirmed that the anti-G250 NTNs could enter the tissue space through tumor blood vessels and bind to tumor cells specifically. In conclusion, anti-G250 nanobody-functionalized targeted nanobubbles could specifically bind to G250-positive RCC cells and enhance the ultrasound imaging of G250-positive RCC xenografts. This study has high-potential clinical application value for the diagnosis and differential diagnosis of renal tumors.

Improved Diagnostic Sensitivity of Bowel Disease of Prematurity on Contrast-Enhanced Ultrasound

Bowel diseases of prematurity, including necrotizing enterocolitis, are dreaded ailments of neonates. Early diagnosis is difficult, with clinical and radiographic findings often inconclusive. We present a novel use of contrast-enhanced ultrasound in detection of pediatric bowel disease. Early identification of compromised blood flow or an at-risk bowel can be quantitatively detected and monitored. This ability has implications for guidance of emerging therapies, allowing targeting of inflammation. These findings represent an advancement in detection of bowel disease in neonates.

Contrast-enhanced ultrasound features of malignant focal liver masses in dogs

A total of 185 cases (150 retrospectively and 35 prospectively) of malignant liver masses were collected. In the retrospectively collected cases hyperenhancement during wash-in was the most common feature in HCCs but there was a high percentage of cases showing no enhancement or hypo/isoenhancement. ICCs displayed a large variety of contrast enhancement patterns and, although statically significant differences between ICCs and HCCs were evident, no clear distinction between these two pathologies was possible based only on their CEUS appearance. Sarcomas displayed all the possible degrees of wash-in enhancement with non-enhancing being the most common appearance. Metastases displayed all the possible contrast-enhancement patterns, with the most common being hyperenhancement in the wash-in phase followed by hypoenhancement in the wash-out phase. A decision tree was developed based on the features of the retrospectively selected cases. Based on the developed decision tree 27/35 prospectively collected cases were correctly classified. Even if some significant differences among groups were evident, all the histotypes displayed all the possible patterns of contrast enhancement, and, therefore, the differentiation of liver masses in dogs based only on their CEUS features is not feasible and, therefore, cytology or histopathology is required.

Liver contrast-enhanced sonography: computer-assisted differentiation between focal nodular hyperplasia and inflammatory hepatocellular adenoma by reference to microbubble transport patterns

OBJECTIVE

A new computer tool is proposed to distinguish between focal nodular hyperplasia (FNH) and an inflammatory hepatocellular adenoma (I-HCA) using contrast-enhanced ultrasound (CEUS). The new method was compared with the usual qualitative analysis.

METHODS

The proposed tool embeds an "optical flow" algorithm, designed to mimic the human visual perception of object transport in image series, to quantitatively analyse apparent microbubble transport parameters visible on CEUS. Qualitative (visual) and quantitative (computer-assisted) CEUS data were compared in a cohort of adult patients with either FNH or I-HCA based on pathological and radiological results. For quantitative analysis, several computer-assisted classification models were tested and subjected to cross-validation. The accuracies, area under the receiver-operating characteristic curve (AUROC), sensitivity and specificity, positive predictive values (PPVs), negative predictive values (NPVs), false predictive rate (FPRs) and false negative rate (FNRs) were recorded.

RESULTS

Forty-six patients with FNH (n = 29) or I-HCA (n = 17) with 47 tumours (one patient with 2 I-HCA) were analysed. The qualitative diagnostic parameters were accuracy = 93.6%, AUROC = 0.94, sensitivity = 94.4%, specificity = 93.1%, PPV = 89.5%, NPV = 96.4%, FPR = 6.9% and FNR = 5.6%. The quantitative diagnostic parameters were accuracy = 95.9%, AUROC = 0.97, sensitivity = 93.4%, specificity = 97.6%, PPV = 95.3%, NPV = 96.7%, FPR = 2.4% and FNR = 6.6%.

CONCLUSIONS

Microbubble transport patterns evident on CEUS are valuable diagnostic indicators. Machine-learning algorithms analysing such data facilitate the diagnosis of FNH and I-HCA tumours.

KEY POINTS

• Distinguishing between focal nodular hyperplasia and an inflammatory hepatocellular adenoma using dynamic contrast-enhanced ultrasound is sometimes difficult. • Microbubble transport patterns evident on contrast-enhanced sonography are valuable diagnostic indicators. • Machine-learning algorithms analysing microbubble transport patterns facilitate the diagnosis of FNH and I-HCA.

Contrast enhanced ultrasound: A review of radiology applications

Ultrasound contrast agents have been used for decades in Europe and Asia for cardiac and abdominal imaging and are now being more commonly utilized in the United States for radiology applications. Our article reviews the basics of contrast-enhanced ultrasound including how the contrast agent works, advantages and disadvantages, as well as pearls and pitfalls to help the radiologist efficiently integrate this technology into day-to-day clinical practice. We also discuss the diagnosis of focal hepatic lesions as well as off-label applications such as evaluation of renal masses.

The role of EUS in diagnosis and treatment of liver disorders

Background and aim  Transabdominal ultrasound (US), computed tomographic scanning (CT) and magnetic resonance imaging (MRI) are established diagnostic tools for liver diseases. Percutaneous transhepatic cholangiography is used to perform hepatic interventional procedures including biopsy, biliary drainage procedures, and radiofrequency ablation. Despite their widespread use, these techniques have limitations. Endoscopic ultrasound (EUS), a tool that has proven useful for evaluating the mediastinum, esophagus, stomach, pancreas, and biliary tract, has an expanding role in the field of hepatology complementing the traditional investigational modalities. This review aimed to assess the current scientific evidence regarding diagnostic and therapeutic applications of EUS for hepatic diseases.

Contrast-Enhanced Ultrasound Guidance for Interventional Procedures

Since its introduction, contrast-enhanced ultrasound (CEUS) has gained an important role in the diagnosis and management of abdominal and pelvic diseases. Contrast-enhanced ultrasound can improve lesion detection rates as well as success rates of interventional procedures when compared to conventional ultrasound alone. Additionally, CEUS enables the interventionalist to assess the dynamic enhancement of different tissues and lesions, without the adverse effects of contrast-enhanced computed tomography, such as exposure to ionizing radiation and nephrotoxicity from iodinated contrast material. This review article describes the various applications and advantages of the use of CEUS to enhance performance of ultrasound-guided interventions in the abdomen and pelvis.

A case of primary clear cell hepatocellular carcinoma comprised mostly of clear cells

Clear cell hepatocellular carcinoma (CHCC) is defined as a tumor which contains more than 50% of clear cells. However, CHCC with more than 90% of clear cells are extremely rare. We report a case of a 65-year-old woman who was found to have a solitary mass, which was histologically diagnosed as clear cell hepatocellular carcinoma composed of 90% or more clear cells. The tumor presented rim arterial phase hyperenhancement in computed tomography, magnetic resonance imaging, and computed tomography during hepatic arteriography, and was classified as LR-M category according to The Liver Imaging Reporting and Data System version 2018(LI-RADS v2018). This tumor may mimic other tumors with similar radiographic features, such as intrahepatic cholangiocellular carcinoma and metastatic tumor.

A Prospective Assessment of the Diagnostic Value of Contrast-Enhanced Ultrasound, Dynamic Computed Tomography and Magnetic Resonance Imaging for Patients with Small Liver Tumors

AIM

This prospective study assessed the diagnostic value of contrast-enhanced ultrasound (CEUS) using long Kupffer phase enhancement for adults with liver tumor size of less than 3 cm. Performance comparisons were also conducted with dynamic computed tomography (CT) and magnetic resonance imaging (MRI).

BACKGROUND

CEUS has emerged as a reliable image modality, since the development of second-generation contrast medium with long Kupffer phase enhancement. Nonetheless, dynamic CT and MRI are currently the standard imaging tools for the diagnosis of liver cancers, and the diagnostic value of CEUS for liver cancer has yet to be universally accepted.

METHODS

Sixty-six adult patients suspected of having liver tumors smaller than 3 cm underwent CEUS, dynamic CT, and MRI examinations independently. Subsequent tumor biopsies were used to verify the diagnostic performance of the three imaging modalities.

RESULTS

The diagnostic odds ratio (DOR, 95% CI) for hepatocellular carcinoma were as follows: CEUS (52.8, 11.4-243), CT (29.29, 7.36-116), and MRI (19.43, 5.44-69.4); for metastasis: CEUS (200, 19.1-2095), CT (24, 5.05-114), and MRI (32, 6.56-156); and all liver malignancy: CEUS (260, 12.7-5310), CT (2.57, 0.55-12.1), and MRI (5.22, 1.25-21.8). CEUS achieved the best differentiation performance.

CONCLUSIONS

CEUS outperformed dynamic CT and MRI in terms of diagnostic performance when dealing with small liver tumors (<3 cm).

Contrast-Enhanced Ultrasound Imaging of Breast Masses: Adjunct Tool to Decrease the Number of False-Positive Biopsy Results

OBJECTIVES

This pilot study evaluated use of contrast-enhanced ultrasound (CEUS) to reduce the number of benign breast masses recommended for biopsy.

METHODS

This prospective study included 131 consenting women, from October 2016 to June 2017, with American College of Radiology Breast Imaging Reporting and Data System category 4a, 4b, and 4c masses detected by mammography, conventional ultrasound (US), or both. Contrast-enhanced US examinations (using intravenous injection of perflutren lipid microspheres or sulfur hexafluoride lipid-type A microspheres) were performed before biopsy. Qualitative and quantitative CEUS parameters were compared with reference standard histopathologic results from biopsy of 131 masses.

RESULTS

There were 109 benign, 6 high-risk, and 16 malignant masses, with a median size of 12 mm (range, 4 to 48 mm) on conventional US imaging. Of 131 masses, 93 (71%) enhanced on CEUS imaging, including 73 of 109 (67%) benign, 6 of 6 (100%) high-risk, and 14 of 16 (87.5%) malignant. Thirty-eight lesions did not enhance, including 36 of 109 (33%) benign and 2 of 16 (12.5%) malignant. Prediction models using recursive petitioning revealed that CEUS may reduce 31% (95% confidence interval, 23%, 40%) of benign biopsies for masses that are: nonenhancing with circumscribed margins or enhancing with an oval shape and homogeneous enhancement. Quantitative parameters indicated that benign masses had the longest time to peak (P = .078), highest time-to-peak ratio of mass to background (P = .036), lowest peak intensity (P = .021), and smallest difference in peak intensity between the mass and background (P = .079) compared to high-risk and malignant lesions.

CONCLUSIONS

Contrast-enhanced US may be a valuable modality that can be used to predict benign pathologic results of breast masses, thereby reducing the number of biopsies.

[CEUS-Diagnostic of malignant liver lesions]

CLINICAL/METHODICAL ISSUE

Cross-sectional modalities or conventional ultrasound are not always able to sufficiently identify and characterize malignant liver lesions.

STANDARD RADIOLOGICAL METHODS

The evaluation of malignant liver lesions in conventional ultrasound relies on echostructure, shape and borders, but often warrants additional contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI) studies.

METHODICAL INNOVATIONS

Contrast-enhanced ultrasound (CEUS) is a relatively safe imaging technique used for the detection and characterization of malignant liver lesions. The use of a second-generation contrast agent in dynamic real-time imaging allows the visualization of vascularization in any kind of liver lesion as well as liver perfusion during the arterial, portal venous and late phase.

PERFORMANCE

Due to the different enhancement patterns, it is possible to differentiate a liver lesion with high diagnostic accuracy (over 90%).

ACHIEVEMENTS

CEUS is a helpful complementary technique to cross-sectional imaging for the evaluation of unclear liver lesions and may frequently obviate additional contrast-enhanced MRI or CT studies.

PRACTICAL RECOMMENDATIONS

CEUS enables the detection and characterization of liver lesions in real time.

Imaging of Pancreatic-Neuroendocrine Tumours: An Outline of Conventional Radiological Techniques

IIntroduction:

Pancreatic Neuroendocrine Tumours (p-NETs) are an important disease entity and comprise of peptide-secreting tumours often with a functional syndrome.

:

Accounting for a small percentage of all pancreatic tumours, they have a good overall survival rate when diagnosed early, with surgery being curative. The role of nuclear medicine in the diagnosis and treatment of these tumours is evident. However, the vast majority of patients will require extensive imaging in the form of conventional radiological techniques. It is important for clinicians to have a fundamental understanding of the p-NET appearances to aid prompt identification and to help direct management through neoplastic staging.

Methods:

This article will review the advantages and disadvantages of conventional radiological techniques in the context of p-NETs and highlight features that these tumours exhibit.

Conclusion:

Pancreatic neuroendocrine tumours are a unique collection of neoplasms that have markedly disparate clinical features but similar imaging characteristics. Most p-NETs are small and welldefined with homogenous enhancement following contrast administration, although larger and less welldifferentiated tumours can demonstrate areas of necrosis and cystic architecture with heterogeneous enhancement characteristics.

:

Prognosis is generally favourable for these tumours with various treatment options available. However, conventional radiological techniques will remain the foundation for the initial diagnosis and staging of these tumours, and a grasp of these modalities is extremely important for physicians.

Hepatocyte Injury Induced by Contrast-Enhanced Diagnostic Ultrasound

OBJECTIVES

Contrast-enhanced diagnostic ultrasound (US) has a potential to induce localized biological effects. The potential for contrast-enhanced diagnostic US bioeffects in liver were researched, with guidance from a report by Yang et al (Ultrasonics 2012; 52:1065-1071).

METHODS

Contact and standoff scanning was performed for 10 minutes with a diagnostic US phased array at 1.6 MHz during bolus injection or infusion of a contrast agent at a high dose. The impact of the imaging on rat liver was investigated by measuring enzyme release, microvascular leakage, and staining of injured hepatocytes.

RESULTS

The results showed liver enzyme release at 30 minutes, indicating liver injury, and elevated extraction of Evans blue dye, indicating microvascular leakage. In addition, Evans blue and trypan blue vital-staining methods revealed scattered stained cells within the US scan plane. For the Evans blue method, fluorescent cell counts in frozen sections were greatest for standoff exposure with contrast infusion. The count decreased strongly with depth for bolus injection, which was probably reflective of the high attenuation noted for this agent delivery method.

CONCLUSIONS

The results qualitatively confirmed the report by Yang et al and additionally showed hepatocyte vital staining. Research is needed to determine the threshold for the effects and the contrast agent dose response.

Findings of contrast-enhanced ultrasonography with Sonazoid for cholangiocellular adenoma in three dogs

Contrast-enhanced ultrasonography (CEUS) is useful to distinguish benign and malignant focal liver lesions in dogs. Cholangiocellular adenoma is an extremely rare benign tumor in dogs and has not been examined using CEUS with Sonazoid. The aim of this study was to describe findings of CEUS with Sonazoid in three dogs with cholangiocellular adenoma. All three dogs showed contrast defects in the Kupffer phase and these findings mimicked malignant neoplasia during the Kupffer phase. Moreover, all dogs showed early washout and hypoechoic lesions relative to the surrounding normal liver parenchyma in the portal phase. To our knowledge, this is the first study to report that CEUS findings of cholangiocellular adenoma with Sonazoid mimicked malignancy in three dogs.

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.

Identification of two distinct hereditary hemorrhagic telangiectasia patient subsets with different hepatic perfusion properties by combination of contrast-enhanced ultrasound (CEUS) with perfusion imaging quantification

Background

Hereditary hemorrhagic telangiectasia (HHT) is marked by arteriovenous fusion comprising hepatic vascular malformations (HVaMs) with the chance of bleeding.

Aims

We investigated HVaMs in HHT patients by combination of contrast-enhanced ultrasound (CEUS) with perfusion imaging quantification to be able to sub-classify a high risk cohort of asymptomatic HHT patients.

Methods

The imaging characteristics on CEUS in 34 patients (aged 21–84 years; mean 58.9) with HHT were retrospectively evaluated. Real-time contrast harmonic imaging, sulfur hexafluoride-filled microbubbles and motion adjustment were utilized. Cine loops of the liver were digital stored, perfusion was quantified using a software reading DICOM data`s.

Results

HVaMs were diagnosed in 31 out of 34 patients. Significant uppermost peak enhancement (PE), wash-in area under the curve (WiAUC) and wash-in perfusion index (WiPI) were identified in the shunt region (100%), next in the hilar region (PE 32.6%; WiAUC 33.9%; WiPI 34.1%), and the lowest in the hepatic parenchyma (PE 10.2%; WiAUC 12.0%; WiPI 9.5%). The perfusion parameters in the shunt region compared to the other regions were significantly increased in one subgroup of patients. Consistent with this, the intrahepatic portal vein diameter and Buscarini grading was significantly higher, while portal vein peak velocity was significantly lower in this patient subset. By statistical analysis, we could correlate PE and WiPI to these clinical parameters, while WiAUC showed no clinical association.

Conclusions

For the first time we combined CEUS findings with motion adjustment software to quantitative determine perfusion parameters of a cohort of HHT patients. Hereby, we could identify a subset of HHT patients with two markedly increased parameter values in the shunt region compared to the hilus/hepatic parenchyma. This could contribute to sub-classify a high-risk group of HHT patients with therapeutic indication.

Contrast-enhanced ultrasound approach to the diagnosis of focal liver lesions: the importance of washout

Contrast-enhanced ultrasound (CEUS) is a powerful technique for differentiating focal liver lesions (FLLs) without the risks of potential nephrotoxicity or ionizing radiation. In the diagnostic algorithm for FLLs on CEUS, washout is an important feature, as its presence is highly suggestive of malignancy and its characteristics are useful in distinguishing hepatocellular from nonhepatocellular malignancies. Interpreting washout on CEUS requires an understanding that microbubble contrast agents are strictly intravascular, unlike computed tomography or magnetic resonance imaging contrast agents. This review explains the definition and types of washout on CEUS in accordance with the 2017 version of the CEUS Liver Imaging Reporting and Data System and presents their applications to differential diagnosis with illustrative examples. Additionally, we propose potential mechanisms of rapid washout and describe the washout phenomenon in benign entities.

SIUMB guidelines and recommendations for the correct use of ultrasound in the management of patients with focal liver disease

The present document describes the SIUMB (Italian Society of Ultrasound in Medicine and Biology) guidelines for the use of ultrasound in the management of focal liver disease. The aim of the paper is to provide a clinical practice guideline for Italian physicians who are approaching the ultrasound study of a focal liver lesion. In particular, these guidelines provide simple indications, recommendations and general practice advices for the correct use of contrast-enhanced ultrasound (CEUS) in this scenario. They represent the SIUMB position of the ultrasound role in the diagnostic flow charts of the principal focal liver lesions, and are in agreement with other, previously published national and international guidelines.

Primary Application of Micro-Flow Imaging Technology in the Diagnosis of Hepatic Tumors

The purpose of the study was to evaluate the vascular architecture of focal liver lesions with the newly released non-contrast micro-flow imaging (MFI) technique. Eighty patients with 80 hepatic tumors were enrolled in this study. The richness of displayed blood flow was first compared with color Doppler flow imaging using grades according to Adler's method. The results indicated that MFI outperformed color Doppler flow imaging with a statistically significant difference (p <0.0001). With the enhanced position in arterial phase of contrast-enhanced ultrasound imaging as the ground truth, the displayed blood flow distribution within tumors in MFI was further evaluated. The coincidence rate between MFI and contrast-enhanced ultrasound was 73.75% (59/80), which was higher than that of color Doppler flow imaging (52.5%, 42/80) (p < 0.0001). Moreover, for the five cases of focal nodular hyperplasia, MFI clearly revealed the spoke-wheel or radiating intra-tumoral vasculature, a finding specific to the diagnosis of focal nodular hyperplasia.

Intrahepatic bile duct adenoma in a patient with gastric cancer

We report a case of intrahepatic bile duct adenoma (BDA) detected during laparoscopic distal gastrectomy for gastric cancer. A 70-year-old man was referred to our hospital for the treatment of gastric cancer. Esophagogastroduodenoscopy revealed an irregular, nodular, and elevated lesion on the greater curvature side of the middle third of the stomach. Abdominal contrast-enhanced computed tomography showed wall thickening with homogeneous enhancement in the middle part of the stomach, and no lesions in the liver. The patient underwent laparoscopic distal gastrectomy with regional lymphadenectomy, and during the operation a small whitish nodule was observed on the lateral segment of the liver surface. The lesion was excised by partial resection of the liver for the purpose of both histological diagnosis and treatment. Pathological examination of the liver lesion revealed no structural or cellular atypia, no stromal invasion, and immunohistochemical positivity for CK7 and CK19, but negativity for p53. The final diagnosis was well-differentiated adenocarcinoma invading the gastric serosal layer without lymph node metastasis, and intrahepatic BDA measuring 0.4 × 0.3 cm. Following surgery, the patient remained symptom-free without evidence of recurrence for 5 months. To the best of our knowledge, this is the first case of BDA with gastric cancer. Because it is difficult to distinguish BDA from other liver tumors including metastatic cancer due to its characteristically small size and lack of specific morphological features on standard imaging, surgical resection should be considered as the most suitable approach for both accurate diagnosis and treatment.

Patterns of Recurrence after Resection for Pancreatic Neuroendocrine Tumors: Who, When, and Where?

BACKGROUND/AIMS

Pancreatic neuroendocrine tumors (pan-NENs) represent an increasingly common indication for pancreatic resection, but there are few data regarding possible recurrence after surgery. The aim of the study was to describe the frequency, timing, and patterns of recurrence after resection for pan-NENs with consequent implications for postoperative follow-up.

METHODS

We performed a retrospective analysis of pan-NENs resected between 1990 and 2015 at The Pancreas Institute, University of Verona Hospital Trust. Predictors of recurrence were assessed. Survival analysis was conducted using the Kaplan-Meier and conditional survival (CS) methods.

RESULTS

The cohort consisted of 487 patients with a median follow-up of 71 months. Recurrence developed in 12.3%: 54 (11.1%) liver metastases, 11 (2.3%) local recurrence, 10 (2.1%) nodal recurrence, and 8 (1.6%) metastases in other organs. Thirty-one (6.4%) died due to disease recurrence. Size > 21 mm, G3 grade, nodal metastasis, and vascular infiltration were independent predictors of overall recurrence. Recurrence occurred either during the first year of follow-up (n = 9), or after 10 years (n = 4). CS analysis revealed that nonfunctioning G1 pan-NEN ≤20 mm without nodal metastasis or vascular invasion had a negligible risk of developing recurrence. In the present series, after 5 years of follow-up without developing recurrence, tumor recurrence occurred only in the form of liver metastases.

CONCLUSIONS

Recurrence of pan-NENs is rare and is predicted by tumor size, nodal metastasis, grading, and vascular invasion. Patients with G1 pan-NEN without nodal metastasis and vascular invasion may be considered cured by surgery. After 5 years without recurrence, follow-up should focus on excluding the development of liver metastases.

Influence of Microbubble Size and Pulse Amplitude on Hepatocyte Injury Induced by Contrast-Enhanced Diagnostic Ultrasound

Recent research has found that contrast-enhanced diagnostic ultrasound (CEDUS) has the potential to induce localized injury in the liver, with clearly observable effects for contrast agent doses higher than the recommended dose and maximal mechanical index values. This study was undertaken to assess effects with intermittent exposure at lower contrast doses of infusion and at reduced output to determine thresholds. In addition, microbubble (MB) suspensions with enhanced content of larger MBs were tested. Exposure from a phased array probe (GE Vivid 7 Dimension, GE Vingmed Ultrasound, Horten, Norway) was applied at 1.6 MHz and 1-s intermittent frame trigger for 10 min with infusion of MB suspension with normal (1.8 µm), medium (3.1 µm) and large (5.3 µm) mean MB diameters. The bio-effect endpoint was the count of hepatocytes stained with Evans blue dye in frozen sections. For the normal MBs, the count increased for clinically relevant infusion dosages, but leveled off above 20 µL/kg/min. The evidence of injury declined with time from 30 min to 4 h and was lacking at 24 h. The exposure thresholds in terms of peak rarefactional pressure amplitude, divided by the square root of frequency (in situ mechanical index) were 1.7, 1.3 and 1.2 for the normal-, medium- and large-sized MB suspensions. The enhanced efficacy for larger MBs lends support to the two-criterion model for cavitational microvascular injury during CEDUS. Overall, CEDUS in liver appears to have markedly less potential for induction of tissue injury than has been reported in other tissues, which indicates a satisfactory safety profile for CEDUS using recommended parameters in normal liver.

Clinical diagnostic value of contrast-enhanced ultrasound and TI-RADS classification for benign and malignant thyroid tumors: One comparative cohort study

To evaluate the diagnostic efficacy and clinical value of contrast-enhanced ultrasonography (CEUS) plus TI-RADS classification in benign and malignant thyroid tumors compared with either method alone.The informed consent was signed all patients. A total of 370 patients with thyroid tumors of TI-RADS category 3 and 4 were recruited, with 432 thyroid nodules. They respectively received routine ultrasonography and CEUS. The nodules were reclassified according to CEUS scoring, and a combined diagnosis was made. The pathological results were taken as the gold standard. The sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV) and area under the ROC curve were calculated for the 3 diagnostic methods. The diagnostic efficacy was compared by using Student t test, Pearson chi-square (χ) test, McNemar chi-square (χ) test or Z test. Student t test and logistic regression were employed for comparing different imaging features of benign and malignant thyroid tumors on CEUS and risk analysis.Of 432 thyroid nodules, there were 258 malignant nodules (59.72%) and 174 benign ones (40.28%). By logistic regression, 6 suspicious features on CEUS were considered significant for differentiating malignant from benign tumors: slow entry of contrast agents during enhancement stage (OR = 15.610, P = .001), slow time to peak (OR = 7.416, P = .002), non-uniform enhancement (OR = 10.076, P = .023), enhancement pattern (irregular) (OR = 36.233, P = .002), enhancement boundary (unclear) (OR = 25.300, P = .012), and no ring-like enhancement (OR = 25.297, P = .004). CEUS plus TI-RADS classification showed a higher diagnostic efficacy for differentiating between benign and malignant thyroid tumors. The Se was 85.66% (0.806-0.896), Sp 83.33% (0.768-0.884), PPV 88.40% (0.836-0.919), NPV 79.67% (0.729-0.851), and AUC 0.867 ± 0.019 (0.815-0.889). The above indicators were of statistical significance as compared with TI-RADS classification or CEUS alone (P <.05).CEUS can more clearly visualize microvascular distribution of the nodules and offers a new approach to diagnose benign and malignant thyroid tumors. TI-RADS classification plus CEUS is more accurate than TI-RADS classification alone. This combined approach is worthy of clinical popularization.

Uncommon Finding of a Gastrointestinal Stromal Tumor in a Patient with Hyperechoic Liver Lesions - Case Report

Introduction: Hyperechoic liver lesions identified by conventional ultrasonography are diverse in underlying pathology and most of the time require further investigations. Gastrointestinal stromal tumors (GIST) are rare neoplasms of the gastrointestinal tract which are uncommonly found in metastatic stages at first presentation.

Case report: We present the case of a 51 years old woman with nonspecific symptoms in which conventional ultrasonography showed hyperechoic lesions in the right lobe of the liver with a diameter up to 40 mm. Esophagogastroduodenoscopy revealed a submucosal tumor on the small curvature of the stomach, on the anterior wall, with central ulceration, with normal narrow band imaging (NBI) mucosal pattern and negative gastric biopsy. Contrast enhanced ultrasonography was performed, describing multiple lesions with inhomogeneous enhancement in the arterial phase and rapid washout at the end of arterial phase. Endoscopic ultrasound with fine needle aspiration (EUS-FNA) biopsy examination was definitive for the final diagnosis of epithelioid gastric gastrointestinal stromal tumor. The patient was diagnosed with T2N0M1 epithelioid gastric GIST, stage IV, and is currently under treatment with tyrosine kinase inhibitors.

Conclusions: GIST represent a diagnostic challenge in medical practice because of its size, unusual location in the submucosal layer and lack of symptoms. The role of EUS-FNA is of paramount importance in increasing the accuracy of diagnosis in the case of GIST. The particularity in our case consists of the unusual presentation with the lack of specific symptoms and signs associated with the presence of metastatic lesions at the moment of the diagnosis of GIST.

Outcome of liver lesions indeterminate for malignancy on ultrasound: the role of patient age, risk status, and lesion echogenicity

PURPOSE

The purpose of this study was to evaluate the relationship between final outcome of lesions indeterminate for malignancy on ultrasound (US) and patient and imaging characteristics.

METHODS

We identified all patients with indeterminate liver lesions on US between 9/1/2013 and 12/31/2014 using institutional codes based on radiologist opinion. Miscoded lesions (n = 30) and patients with no imaging, pathology, or clinical follow-up at our health system (n = 6) were excluded. Final diagnostic category of malignant, benign, pseudolesion, or indeterminate was assigned using imaging, pathology, and clinical follow-up. Differences in diagnostic categories were compared by patient (age, gender, race, known malignancy. or liver disease) and imaging characteristics (lesion size, echogenicity. and number). Independent likelihood of a benign final diagnostic category was adjusted for significant variables on univariate analysis.

RESULTS

Indeterminate liver lesions on US were found in 153/6813 patients (2%). Final diagnostic categories were malignant (11/153, 7%), benign (94/153, 61%), pseudolesion (42/153, 27%). and indeterminate (6/153, 4%). Nearly one-third of hypoechoic masses in patients with known malignancy or liver disease (i.e., high-risk status) ≥ 46 years of age were malignant (9/28, 32%). On multivariate analysis, patients of age ≥ 61 years and high-risk status were associated with decreased likelihood of benign diagnostic category (OR .19 (95% CI .07-.51) and OR .40 (95% CI .18-.88), p values .001 and .022, respectively).

CONCLUSIONS

2% of patients undergoing abdominal US have sonographically indeterminate liver lesions, of which 7% are malignant. Older, high-risk patients with hypoechoic lesions should receive short-term follow-up as one-third will have malignant lesions. Younger, low-risk patients should receive conservative follow-up, regardless of US imaging features.

Contrast-enhanced ultrasound of the abdominal aorta - current status and future perspectives

Ultrasound has been established as an important diagnostic tool in assessing vascular abnormalities. Standard B-mode and Doppler techniques have inherent limitations with regards to detection of slow flow and small vasculature. Contrast-enhanced ultrasound (CEUS) is a complementary tool and is useful in assessing both the macro- and microvascular anatomy of the aorta. CEUS can also provide valuable physiological information in real-time scanning sessions due to the physical and safety profiles of the administered microbubbles. From a macrovascular perspective, CEUS has been used to characterize aortic aneurysm rupture, dissection and endoleaks post-EVAR repair. With regard to microvasculature CEUS enables imaging of adventitial vasa vasorum thereby assessing aortic inflammation processes, such as monitoring treatment response in chronic periaortitis. CEUS may have additional clinical utility since adventitial vasa vasorum has important implications in the pathogenesis of aortic diseases. In recent years, there have been an increasing number of studies comparing CEUS to cross-sectional imaging for aortic applications. For endoleak surveillance CEUS has been shown to be equal or in certain cases superior in comparison to CT angiography. The recent advancement of CEUS software along with the ongoing development of drug-eluting contrast microbubbles has allowed improved targeted detection and real-time ultrasound guided therapy for aortic vasa vasorum inflammation and neovascularization in animal models. Therefore, CEUS is uniquely suited to comprehensively assess and potentially treat aortic vascular diseases in the future.

Microvascular Invasion in HCC: The Molecular Imaging Perspective

Hepatocellular carcinoma represents the most frequent primary liver tumor; curative options are only surgical resection and liver transplantation. From 1996, Milan Criteria are applied in consideration of patients with cirrhosis and hepatocellular for liver transplantation; nonetheless, more recently, Milan Criteria have been criticized because they appear over conservative. Apart from number and size of lesions and biomarker levels, which already have been associated with poorer prognosis, overall survival and recurrence rates after transplantation are affected also by the presence of vascular invasion. Microvascular invasion suggests a poor prognosis but it is often hard to detect before transplant. Diagnostic imaging and tumor markers may play an important role and become the main tools to define microvascular invasion. In particular, a possible role could be found for computed tomography, magnetic resonance imaging, and positron emission tomography. In this paper, we analyze the possible role of positron emission tomography as a preoperative imaging biomarker capable of predicting microvascular invasion in patients with hepatocellular carcinoma and thus selecting optimal candidates for liver transplantation.

Diffusion-weighted MRI as a screening tool for hepatocellular carcinoma in cirrhotic livers: correlation with explant data-a pilot study

OBJECTIVE

The purpose of this study was to compare the sensitivity and specificity of diffusion-weighted liver MRI alone with complete, multiphasic gadoteridol-enhanced MRI for the detection of hepatocellular carcinoma in cirrhotic patients before liver transplant.

MATERIALS AND METHODS

This single institution retrospective study was performed after IRB approval and was HIPAA compliant. MRI scans of 37 patients who underwent liver transplant were evaluated and findings correlated with liver explant (36) or biopsy (1). All MRI scans were obtained within six months of explant. MRI from 17 patients with liver lesions by report at imaging subsequently proven to be HCC at pathology and 20 controls without liver lesions by imaging and pathology were reviewed in random order on the radiology PACS by three independent readers blinded to the MRI reports and pathology reports in two separate sittings. First, only the diffusion-weighted images (DWI) were interpreted. Second, the complete multiphasic MRI exam with DWI was reviewed. A consensus read was obtained by two separate radiologists who had access to the patients' explant data in order to map lesions. Reader-specific and pooled classification was assessed using sensitivity, specificity, positive predictive value, and negative predictive values and corresponding 95% confidence intervals (CI) for both DWI and complete MRI examination readings compared to pathology. McNemar's test and Kappa coefficient were used to assess differences (agreement) in DWI and complete examination readings.

RESULTS

A total of 37 patients have been studied (25M 12F age range 21-70). Averaged results of the three independent readers demonstrated a sensitivity of 78% (95% CI 65-89%) and specificity of 88% (95% CI 77-95%) for DWI alone for detection of liver lesions, with a positive predictive value of 85% (95% CI 72-94%) and a negative predictive value of 83% (95% CI 71-91%). Review of the complete MRI exam showed a sensitivity of 90% (95% CI 76-97%) and a specificity of 82% (95% CI 66-92%) with a positive predictive value of 83% (95% CI 69-93%) and a negative predictive value of 89% (95% CI 74-97%). McNemar's agreement test revealed no significant difference between the DWI and complete multiphasic interpretations (p = 0.3458), with simple Kappa coefficient of 0.6716 (95% CI 0.5332-0.8110). Lesions identified on DWI ranged in size from 1.5 to 5 cm. Detection of lesions was decreased in the presence of artifact from motion, large ascites, and technical issues.

CONCLUSION

Diffusion-weighted MRI has NPV and PPV comparable to complete multiphasic MRI examination for liver lesion detection in cirrhotic patients and may have a role in screening.

Diagnosis of congenital and acquired focal lesions in the neck, abdomen, and pelvis with contrast-enhanced ultrasound: a pictorial essay

Contrast-enhanced ultrasound (CEUS) is a versatile imaging modality that improves the diagnostic potential of conventional ultrasound. It allows for portable imaging at the bedside. In this paper, we illustrate how CEUS can be used in evaluating several focal lesions in the pediatric population, including liver hemangioma, telangiectasias, splenic hamartomas, and bladder lesions. We describe the ultrasound findings and contrast enhancement patterns associated with these lesions. Findings are correlated with MRI, CT, and/or pathology when available. This paper demonstrates the value of CEUS in improving characterization of many focal lesions in the pediatric population.

CONCLUSION

CEUS is a valuable bedside technique for use in the pediatric population to evaluate focal lesions in various organs, and will allow for safe, more efficient diagnostic imaging. What is Known: • CEUS offers many advantages over CT and MRI and is underutilized in the United States. • It is only FDA approved for vesicoureteral reflux and liver in the pediatric population. However, off label uses are well described. What is New: • This pictorial essay describes ultrasound findings and contrast enhancement patterns associated with liver hemangioma, liver telangiectasia, splenic hamartoma, hemorrhagic ovarian cyst, urachal remnant, spinning top urethras, and kaposiform hemangioendothelioma. • We demonstrate the utility of CEUS in expanding the diagnostic potential of conventional ultrasound.

Contrast-Enhanced Transrectal Ultrasound in Focal Therapy for Prostate Cancer

PURPOSE OF REVIEW

Contrast-enhanced transrectal ultrasound (CeTRUS) is an emerging imaging technique in prostate cancer (PCa) diagnosis and treatment. We review the utility and implications of CeTRUS in PCa focal therapy (FT).

RECENT FINDINGS

CeTRUS utilizes intravenous injection of ultrasound-enhancing agents followed by high-resolution ultrasound to evaluate tissue microvasculature and differentiate between benign tissue and PCa, with the latter demonstrating increased enhancement. The potential utility of CeTRUS in FT for PCa extends to pre-, intra- and post-operative settings. CeTRUS may detect PCa, facilitate targeted biopsy and aid surgical planning prior to FT. During FT, the treated area can be visualized as a well-demarcated non-enhancing zone and continuous real-time assessment allows immediate re-treatment if necessary. Following FT, the changes on CeTRUS are immediate and consistent, thus facilitating repeat imaging for comparison during follow-up. Areas suspicious for recurrence may be detected and target-biopsied. Enhancement can be quantified using time-intensity curves allowing objective assessment and comparison. Based on encouraging early outcomes, CeTRUS may become an alternative imaging modality in prostate cancer FT. Further study with larger cohorts and longer follow-up are needed.