Contrast-enhanced ultrasound of benign liver lesions

Development and Characterization of Hemoglobin Microbubbles for Acoustic Blood Oxygen Level Dependent Imaging

Oxygen levels in tissues and organs are crucial for their normal functioning, and approaches to monitor them non-invasively have wide biological and clinical applications. In this study, we developed a method of acoustically detecting oxygenation using contrast-enhanced ultrasound (CEUS) imaging. Our approach involved the use of specially designed hemoglobin-based microbubbles (HbMBs) that reversibly bind to oxygen and alter the state-dependent acoustic response. We confirmed that the bioactivity of hemoglobin remained intact after the microbubble shell was formed, and we did not observe any significant loss of heme. We conducted passive cavitation detection (PCD) experiments to confirm whether the acoustic properties of HbMBs vary based on the level of oxygen present. The experiments involved driving the HbMBs with a 1.1 MHz focused ultrasound transducer. Through the PCD data collected, we observed significant differences in the subharmonic and harmonic responses of the HbMBs when exposed to an oxygen-rich environment versus an oxygen-depleted one. We used a programmable ultrasound system to capture high-frame rate B mode videos of HbMBs in both oxy and deoxy conditions at the same time in a two-chambered flow phantom and observed that the mean pixel intensity of deoxygenated HbMB was greater than in the oxygenated state using B-mode imaging. Finally, we demonstrated that HbMBs can circulate in vivo and are detectable by a clinical ultrasound scanner. To summarize, our results indicate that CEUS imaging with HbMB has the potential to detect changes in tissue oxygenation and could be a valuable tool for clinical purposes in monitoring regional blood oxygen levels.

The contribution of ultrasound in the diagnostic pathway of a symptomatic hepatocellular adenoma arising from ectopic liver

Ectopic liver (EL) is a rare congenital anomaly characterized by the presence of a mass composed of hepatic tissue localized in a different anatomical location with no connection to the native liver. Usually an incidental finding, EL can rarely cause symptoms such as abdominal pain due to torsion, intraperitoneal bleeding, compression, obstruction, or neoplastic transformation, both benign and malignant. EL is often suspected after instrumental investigations such as ultrasound, CT and MRI, however a definitive diagnosis is necessarily bioptic. Here we report a case of a 22-year-old Italian female patient with acute abdominal pain, who underwent abdominal ultrasound, CEUS with Sonovue®, CT scan and ultrasound-guided biopsy which raised the suspicion of hepatocellular adenoma (H-HCA). After a laparoscopic excision of the lesion a diagnosis of H-HCA was formulated.

Dynamic contrast-enhanced ultrasound characteristics of renal tumors: VueBox™ quantitative analysis

BACKGROUND

VueBoxtrademark has been used for contrast analysis in DCE-US-based quantitative research.

OBJECTIVE

Aim of this study was to use the enhancement-mode and VueBoxtrademark parameters to further evaluate the differential diagnostic value of DCE-US for renal tumors.

METHODS

24 patients with renal tumors, including 7 benign and 17 malignant, were retrospectively analyzed.The DCE-US enhancement-mode and VueBoxtrademark parameters correlated with the histological analyses of tumors were obtained and analyzed.

RESULTS

The benign and malignant renal tumors showed significant differences in enhancement degree (P = 0.017) and presence of a pseudocapsule (P = 0.009) and in the VueBoxtrademark parameters FT (P = 0.045) and RT (P = 0.039). Receiver operating characteristic analysis for differential diagnosis of benign and malignant renal tumors showed that AUC for a combination of enhancement degree and presence of a pseudocapsule was greater (AUC = 0.815) than the values for either parameter of enhancement mode alone. Similarly, the AUC for a combination of RT and FT was greater (AUC = 0.798) than the values for RT or FT alone. A comprehensive index obtaining by combining the enhancement-mode and VueBoxtrademark parameters showed the largest AUC (AUC = 0.916) with relatively high accuracy (87.50%), sensitivity (76.50%), and specificity (85.70%).

CONCLUSIONS

DCE-US with enhancement mode and quantitative analysis can facilitate preoperative differential diagnosis of benign and malignant renal tumors.

High-frame-rate contrast-enhanced ultrasound findings of liver metastasis of duodenal gastrointestinal stromal tumor: A case report and literature review

BACKGROUND

Liver metastasis of duodenal gastrointestinal stromal tumor (GIST) is rare. Most reports mainly focus on its treatment and approaches to surgical resection, while details on its contrast-enhanced ultrasound (CEUS) findings are lacking. The diagnosis and imaging modalities for this condition remain challenging.

CASE SUMMARY

A 53-year-old Chinese man presented with mild signs and symptoms of the digestive tract. He underwent routine examinations after GIST surgery. Magnetic resonance imaging showed a 2.3 cm hepatic space-occupying lesion. All the laboratory test results were within normal limits. For further diagnostic confirmation, we conducted high frame rate CEUS (H-CEUS) and found a malignant perfusion pattern. Heterogeneous concentric hyper-enhancement, earlier wash-in than the liver parenchyma, and two irregular vessel columns could be observed at the periphery of the lesion during the arterial phase. Ultrasound-guided puncture biopsy was used to confirm the diagnosis of the lesion as liver metastasis of duodenal GIST. Imatinib was prescribed after biopsy, and the patient’s clinical course was monitored.

CONCLUSION

H-CEUS is useful for detecting microcirculation differences, wash-in patterns, and vascular morphogenesis and diagnosing liver metastasis of duodenal GIST.

Differentiating malignant and benign focal liver lesions in children using CEUS LI-RADS combined with serum alpha-fetoprotein

BACKGROUND

Contrast-enhanced ultrasound (CEUS) can be used to diagnose focal liver lesions (FLLs) in children. The America College of Radiology developed the CEUS liver imaging reporting and data system (LI-RADS) for standardizing CEUS diagnosis of FLLs in adult patients. Until now, no similar consensus or guidelines have existed for pediatric patients to improve imaging interpretation as adults.

AIM

To evaluate the performance of CEUS LI-RADS combined with alpha-fetoprotein (AFP) in differentiating benign and malignant FLLs in pediatric patients.

METHODS

Between January 2011 and January 2021, patients ≤ 18 years old who underwent CEUS for FLLs were retrospectively evaluated. The following criteria for diagnosing malignancy were proposed: Criterion I considered LR-4, LR-5, or LR-M lesions as malignancies; criterion II regarded LR-4, LR-5 or LR-M lesions with simultaneously elevated AFP (≥ 20 ng/mL) as malignancies; criterion III took LR-4 Lesions with elevated AFP or LR-5 or LR-M lesions as malignancies. The sensitivity, specificity, accuracy and area under the receiver operating characteristic curve (AUC) were calculated to determine the diagnostic value of the aforementioned criteria.

RESULTS

The study included 63 nodules in 60 patients (mean age, 11.0 ± 5.2 years; 26 male). There were no statistically significant differences between the specificity, accuracy, or AUC of criterion II and criterion III (95.1% vs 80.5%, 84.1% vs 87.3%, and 0.794 vs 0.902; all P > 0.017). Notably, criterion III showed a higher diagnostic sensitivity than criterion II (100% vs 63.6%; P < 0.017). However, both the specificity and accuracy of criterion I was inferior to those of criterion II and criterion III (all P < 0.017). For pediatric patients more than 5 years old, the performance of the three criteria was overall similar when patients were subcategorized by age when compared to all patients in aggregate.

CONCLUSION

CEUS LI-RADS combined with AFP may be a powerful diagnostic tool in pediatric patients. LR-4 with elevated AFP, LR-5 or LR-M lesions is highly suggestive of malignant tumors.

When Benign Behaves Badly: Atypical Hemangiomas on Contrast-Enhanced Ultrasonography

ABSTRACT

Hemangioma is the most common benign liver tumor and is frequently encountered as an incidental finding on imaging. The classic enhancement pattern of hemangioma is diagnostic on contrast-enhanced ultrasound (CEUS), and it follows the same pattern of enhancement on computed tomography and magnetic resonance imaging. However, there is a subset of hemangiomas that demonstrate atypical enhancement patterns on CEUS. The ability to recognize the different enhancement patterns and discern when additional imaging or biopsy may be necessary is essential to accurately interpret an atypical hemangioma on CEUS. This article reviews various enhancement patterns of hemangioma on CEUS to avoid pitfalls in characterization of focal liver lesions on CEUS.

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.

Focal liver lesions in cirrhosis: Role of contrast-enhanced ultrasonography

Contrast-enhanced ultrasound (CEUS) represents a great innovation for the evaluation of focal liver lesions (FLLs). The main advantage of CEUS is the real-time imaging examination and the very low toxicity in patients with renal failure. Liver cirrhosis has been recognized as a major risk factor for the onset of hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC). HCC in liver cirrhosis develops as the last step of a complex that leads to the gradual transformation from regenerative nodule through dysplastic nodule to HCC. In patients with liver cirrhosis, a surveillance program is recommended consisting of ultrasound (US) for detecting small focal lesions. A wide spectrum of benign and malignant lesions other than HCC may be found in the cirrhotic liver and their differentiation is important to avoid errors in staging diseases that may preclude potentially curative therapies. Several published studies have explored the value of CEUS in liver cirrhosis and they have been shown to have excellent diagnostic and prognostic performances for the evaluation of non-invasive and efficient diagnosis of FLLs in patients at high risk for liver malignancies. The purpose of this article is to describe and discuss CEUS imaging findings of FLLs including HCC and ICC, all of which occur in cirrhotic livers with varying prevalence.

Diagnostic accuracy of three-dimensional contrast-enhanced ultrasound for focal liver lesions: A protocol for systematic review and meta-analysis

BACKGROUND

Contrast-enhanced ultrasound (CEUS) examination is a well-established technique for this purpose with several unique advantages. It is a real-time technology with high temporal resolution. With its unique ability to detect microvascular perfusion, it helps in better characterization of FLL.[1-4] Three-dimensional (3D) CEUS with quantitative analysis is updated in recent years. 3D-CEUS is a new ultrasonic diagnostic technique, which can observe the nourishing vessels of lesions from multiple angles. Previous studies showed that 3D-CEUS can detect tumor nourishing vessels to differentiate benign from malignant focal liver lesions (FLLs). However, the results of these studies have been contradictory. Therefore, this meta-analysis tested the hypothesis that 3D-CEUS is accurate in distinguishing benign and malignant FLLs.

METHODS

We will search PubMed, Web of Science, Cochrane Library, and Chinese biomedical databases from their inceptions to the April 30, 2021, without language restrictions. Two authors will independently carry out searching literature records, scanning titles and abstracts, full texts, collecting data, and assessing risk of bias. Review Manager 5.2 and Stata14.0 software will be used for data analysis.

RESULTS

This systematic review will determine the accuracy of 3D-CEUS in the differential diagnosis between benign and malignant FLLs.

CONCLUSION

Its findings will provide helpful evidence for the accuracy of 3D-CEUS in the differential diagnosis between benign and malignant FLLs.

SYSTEMATIC REVIEW REGISTRATION

INPLASY202150096.

Clinical value of contrast-enhanced computed tomography (CECT) combined with contrast-enhanced ultrasound (CEUS) for characterization and diagnosis of small nodular lesions in liver

Objectives

To explore the clinical value of contrast-enhanced computed tomography (CECT) combined with contrast-enhanced ultrasound (CEUS) for characterization and diagnosis of small nodular lesions in the liver and investigate the association between such small nodular lesions and the degree of tumor differentiation.

Methods

Combined imaging modalities were performed on 120 patients who were admitted by Linyi Maternal and Child Health hospital from December 2018 to December 2020 and diagnosed with hepatic nodular lesions. The CT scans were interpreted by two senior imageologists while the ultrasound scans were analyzed by two senior sonographers. A comparative analysis was carried out on different scan modes and the postoperative or post-puncture pathological results using the t-test, the χ2 test, and the Pearson's correlation analysis.

Results

Compared to the pathological results, definite diagnoses of 55 malignant cases were made using CECT alone, with the coincidence rate of 78.6%; CECT combined with CEUS formed correct diagnoses in 64 cases, and the coincidence rate was up to 91.4%. The difference between the two scan modes was statistically significant (p= 0.03). Based on pathological diagnosis, seventy out of the 120 cases of small nodular lesions were identified as malignant, while the other 50 cases were benign. The single imaging modality diagnosed 63 malignant and 57 benign nodules, whereas the combined modalities identified 68 malignancies and 52 benign conditions. Compared to CECT as a single imaging modality, the combined modalities showed a higher degree of sensitivity and accuracy, and the difference was statistically significant (sensitivity: p= 0.03; accuracy: p= 0.02); in the malignant cases, the magnitudes of contrast enhancement of CT and ultrasound imaging decreased with an increase in the degree of differentiation, indicating a negative correlation between these factors.

Conclusions

CECT combined with CEUS has a higher coincidence rate, greater sensitivity, and better diagnostic accuracy when being used for characterization and diagnosis of small nodular lesions in the liver. A higher degree of tumor differentiation means a decreased magnitude of contrast enhancement and a blurrier boundary, which indicates that CECT and CEUS are complementary to each other in classifying malignant liver nodules. The use of the combined imaging modalities shows clinical value for characterizing small liver nodules and predicting the degree of malignancy.

Contrast-Enhanced Ultrasound as a Main Radiological Diagnostic Method for Primary Liver Neoplasms and Hemangiomas

Contrast-enhanced ultrasound (CEUS) is a relatively new approach for the definitive diagnosis of focal liver lesions (FLL). The essential advantages of CEUS are affordability, absence of radiation, and negligible nephrotoxicity-making this diagnostic approach more preferable.

This review includes data from 39 different research studies published during the last 10 years, selected through the MeSH strategy in PubMed.

We conclude that CEUS is a promising approach for diagnosing primary liver neoplasms and it is an excellent radiological approach for children and pregnant women because of the absence of radiation and nephrotoxicity. Studies showed that CEUS is a very good approach for the differentiation of a variety of hemangiomas and for a detailed description of those findings. Therefore, CEUS is an important and progressive method for the diagnosis of liver neoplasms. The regular use of CEUS will facilitate the diagnosis of primary liver lesions.

New frontiers in liver ultrasound: From mono to multi parametricity

Modern liver ultrasonography (US) has become a “one-stop shop” able to provide not only anatomic and morphologic but also functional information about vascularity, stiffness and other various liver tissue properties. Modern US techniques allow a quantitative assessment of various liver diseases. US scanning is no more limited to the visualized plane, but three-dimensional, volumetric acquisition and consequent post-processing are also possible. Further, US scan can be consistently merged and visualized in real time with Computed Tomography and Magnetic Resonance Imaging examinations. Effective and safe microbubble-based contrast agents allow a real time, dynamic study of contrast kinetic for the detection and characterization of focal liver lesions. Ultrasound can be used to guide loco-regional treatment of liver malignancies and to assess tumoral response either to interventional procedures or medical therapies. Microbubbles may also carry and deliver drugs under ultrasound exposure. US plays a crucial role in diagnosing, treating and monitoring focal and diffuse liver disease. On the basis of personal experience and literature data, this paper is aimed to review the main topics involving recent advances in the field of liver ultrasound.

Relationship between quantitative contrast-enhanced ultrasonography parameters and angiogenesis in primary small hepatocellular carcinoma: A retrospective study

To analyze the correlation between quantitative contrast-enhanced ultrasonography (CEUS) parameters and angiogenesis in primary small hepatocellular carcinoma (sHCC) with varying degrees of differentiation.According to varying degrees of differentiation, a total of 90 primary sHCC patients admitted to our hospital from July 2018 to January 2020 were selected and divided into poorly differentiated group (24 cases), moderately differentiated group (31 cases), and highly differentiated group (35 cases). All patients received real-time CEUS before surgery. The tumor diameter, microvascular morphology, grading of color blood flow, contrast-enhanced performance in different phases, quantitative CEUS parameters, expression of angiogenesis-related genes, and microvessel density (MVD) were compared among the 3 groups. The correlation between quantitative parameters of CEUS and angiogenesis indexes was analyzed by Spearman rank correlation analysis.Spearman rank correlation analysis showed that vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), epidermal growth factor receptor (EGFR), and angiopoietin-2 (Ang-2) expression and MVD were negatively correlated with the time to peak (TTP), wash-out time, and peak accelerating time (PAT) (r < 0, P < .05), and were positively correlated with enhancing slope rate (ESR) and peak intensity increasing rate (PIIR) (r > 0, P < .05).CEUS is able to identify varying degrees of differentiation in primary sHCC, and the quantitative CEUS parameters are closely related to angiogenesis.

Contrast-Enhanced Ultrasound in Children: Implementation and Key Diagnostic Applications

Contrast-enhanced ultrasound (CEUS) utilization is expanding rapidly, particularly in children, in whom the modality offers important advantages of dynamic evaluation of the vasculature, portability, lack of ionizing radiation, and lack of need for sedation. Accumulating data establish an excellent safety profile of ultrasound contrast agents in children. Although only FDA-approved for IV use in children for characterizing focal liver lesions and for use during echocardiography, growing off-label applications are expanding the diagnostic potential of ultrasound. Focal liver lesion evaluation is the most common use of CEUS, and the American College of Radiology Pediatric LI-RADS Working Group recommends including CEUS for evaluation of a newly discovered focal liver lesion in many circumstances. Data also support the role of CEUS in hemodynamically stable children with blunt abdominal trauma, and CEUS is becoming a potential alternative to CT in this setting. Additional potential applications that require further study include evaluation of pathology in the lung, spleen, brain, pancreas, bowel, kidney, female pelvis, and scrotum. This review explores the implementation of CEUS in children, describing basic principles of ultrasound contrast agents and CEUS technique and summarizing current and potential IV diagnostic applications based on pediatric-specific supporting evidence.

Analysis of contrast-enhanced ultrasound features of hepatocellular adenoma according to different pathological molecular classifications

OBJECTIVE

To explore the specific contrast-enhanced ultrasound (CEUS) features of hepatocellular adenomas (HCA) according to their pathological molecular classifications.

METHODS & MATERIALS

In this retrospective study, fifty-three histopathologically proved HCA lesions (mean size, 39.7±24.9 mm) were included. Final histopathological diagnosis of HCA lesions were identified by surgical resection (n = 51) or biopsy (n = 2) specimens. CEUS imaging features were compared among four subgroups according to World Health Organization (WHO) 2019 pathological molecular classifications standards. Analysis of variance (ANOVA) were used for statistical analysis of continuous variables. Fisher's exact test were used for categorical variables. The sensitivity (SE), specificity (SP), and accuracy of CEUS feature in diagnosis of each HCA subtype were calculated and compared.

RESULTS

Final histopathological diagnosis included HNF-1α inactivated HCAs (H-HCA, n = 12), β-catenin activated HCAs (B-HCA, n = 8), inflammatory HCAs (I-HCA, n = 31), and unclassified HCAs (U-HCA, n = 2). During arterial phase of CEUS, all HCAs were hyper-enhanced, 66.6% (8/12) of H-HCAs and 50% (4/8) of B-HCAs displayed complete hyperenhancement, whereas 58.0% (18/31) of I-HCAs showed centripetal filling hyperenhancement pattern (P = 0.016). Hyper-enhanced subcapsular arteries could be detected in 64.5% (20/31) I-HCAs during early arterial phase. During portal venous and late phase, sustained hyper- or iso-enhancement were observed in 91.7% (11/12) of H-HCAs, while most of I-HCAs (61.3%, 19/31) and B-HCAs (7/8, 87.5%) were hypo-enhanced (P = 0.000). Central unenhanced areas were most commonly observed in I-HCAs (29.0%, 9/31) (P = 0.034).

CONCLUSION

Depending on its unique imaging features including enhancement filling pattern, hyper-enhanced subcapsular artery and presence of washout, CEUS might provide helpful diagnostic information for preoperative prediction of various HCA molecular subtypes.

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.

Diagnostic Performance of Contrast-Enhanced Ultrasound in Renal Cancer: A Meta-Analysis

Background

Contrast-enhanced ultrasound (CEUS) is an examination mode for detecting blood vessels in tissues, and it has been gradually used in the diagnosis of kidney cancer in recent years. This study explores the value of contrast-enhanced ultrasound in the clinical diagnosis of renal cancer, and provides an accurate and effective method for clinical diagnosis of renal cancer.

Methods

CEUS and RCC were selected as the keywords. Searching the PubMed and Embase from 2007 to 2020, the original data were abstracted and performed heterogeneity test with the Meta-Disc software. The weighted sensitivity, specificity, positive likelihood ratio and negative likelihood ratio were calculated, as well as the summary receiver operating characteristic (SROC) curve. Further estimated the diagnostic value of CEUS in the research of renal cancer by calculating the area under the curve (AUC). The quality of evidence in researches was evaluated by QUADAS items. Meta-disc, Review Manager 5.3, and STATA 13 were used.

Results

A total of 20 studies were adopted for Meta-analysis. The weighted sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 0.97, 0.86, 6.8, 0.04 and 171, respectively; and AUC was 0.97. The results showed that there was high heterogeneity.

Conclusion

CEUS technology has a good diagnostic value for RCC.

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.

[Benign liver tumors : Diagnostics and treatment]

Benign liver tumors are often detected during routine ultrasound examinations or as an incidental finding in radiological imaging. Only very few benign liver tumors are at risk of becoming malignant. In the majority of cases the differentiation from malignant tumors is currently carried out using imaging procedures. In a few cases of diagnostic uncertainty, a transcutaneous liver biopsy can lead to clarification. If the suspicion of malignancy is substantiated or this cannot be excluded with absolute certainty, the tumor should be removed by partial liver resection.

[Benign liver tumors : Diagnostics and treatment]

Benign liver tumors are often detected during routine ultrasound examinations or as an incidental finding in radiological imaging. Only very few benign liver tumors are at risk of becoming malignant. In the majority of cases the differentiation from malignant tumors is currently carried out using imaging procedures. In a few cases of diagnostic uncertainty, a transcutaneous liver biopsy can lead to clarification. If the suspicion of malignancy is substantiated or this cannot be excluded with absolute certainty, the tumor should be removed by partial liver resection.

Contrast-enhanced ultrasound of liver lesions in children

Initial pediatric imaging of the liver heavily relies on ultrasonography (US) because it is free of ionizing radiation, easily portable and readily available. Although conventional US (gray-scale and color Doppler) is often an excellent screening tool, its relative low specificity compared to CT/MRI limits liver lesion characterization. The United States Food and Drug Administration's recent approval of an intravenous US contrast agent for pediatric liver lesion characterization (sulfur hexafluoride lipid-type A microspheres) and its excellent safety profile have spurred increased interest in contrast-enhanced US for definitive diagnosis of pediatric liver lesions. This review focuses on the safety of contrast-enhanced US, role of contrast-enhanced US in the evaluation of focal liver lesions, basic contrast-enhanced US technique for liver imaging, and interpretation principles. The authors review common focal liver lesions, with special attention to the role of contrast-enhanced US in the pediatric oncology population.

[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.

Intrahepatic mass-forming cholangiocarcinoma growing in a giant hepatic hemangioma: A case report

RATIONALE

Hepatic hemangioma (HH) is a common benign tumor with a high number of normal or abnormal blood vessels. Intrahepatic cholangiocarcinoma (ICC) is a relatively common malignant primary hepatic carcinoma (10%-15%) with high incidence rate and high fatality, yet low discovery rate in the early stages. Ultrasonography (US), computed tomography, and magnetic resonance imaging (MRI) are frequently used and indispensable imaging techniques for the diagnosis of hepatic lesions. It is possible to differentiate a liver lesion from HH with high accuracy owing to their different patterns and hemodynamic characteristics.

PATIENT CONCERNS

A 59-year-old Asian woman was referred to hospital for a hepatic mass, which was 9.0 × 6.5 cm in size, The patient was tested positive for hepatitis B antigen but negative for serum alpha-fetoprotein and carbohydrate antigen 199 and had a slightly elevated carcinoembryonic antigen level (3.56 ng/ml).

DIAGNOSIS

Liver US and MRI were performed. Grey-scale US revealed a huge heterogeneous mass on the right lobe with a point and line-like blood flow signal on Doppler US. Dynamic contrast-enhanced MRI showed heterogeneous annular nodular enhancement in the arterial phase. An initial diagnosis of HH was made based on the clinical history and imaging results; however, histopathologic examination of the liver lesions revealed modest to severe atypical hyperplasia of intrahepatic bile duct epithelium, cancerization, and mid to high differentiated mass-forming type cholangiocarcinoma combined with focal organized hemangioma.

INTERVENTIONS

The intrahepatic mass-forming cholangiocarcinoma (IMCC) lesion was considered a focal organization of hemangioma during operation and was surgically removed. No routine chemotherapy was performed after the operation.

OUTCOMES

The IMCC recurred 23 months after surgery, with elevated serum CA19-9 and CA125. Liver damage was evident, and the patient developed jaundice. The patient was discharged without active treatment and died in 4 months.

LESSONS

Although preoperative imaging of focal hepatic lesions is indispensable, intraoperative frozen section analysis and histopathological examination remain essential for definitive diagnosis. This is particularly important for high-risk patients and those with suspected malignancy.

Value of Contrast-Enhanced Ultrasound in the Diagnosis of Renal Cancer and in Comparison With Contrast-Enhanced Computed Tomography: A Meta-analysis

OBJECTIVES

The purpose of this meta-analysis was to assess the diagnostic accuracy of contrast-enhanced ultrasound (CEUS) in renal cancer and to compare it with contrast-enhanced computed tomography (CECT).

METHODS

A systematic search was performed to recruit eligible original studies published until December 2017. Two reviewers independently extracted data. A meta-analysis was performed, and the pooled sensitivity, specificity, positive and negative likelihood ratios, positive and negative predictive values, diagnostic odds ratio, summary receiver operating characteristic curve, and area under the curve were calculated. The extent and potential sources of heterogeneity were further explored. Moreover, a head-to-head comparison was also performed to compare the diagnostic value between CEUS and CECT in renal cancer.

RESULTS

Twenty-two studies were included in this meta-analysis. The summary sensitivity and specificity of CEUS for detecting renal cancer were 0.96 (95% confidence interval [CI], 0.94-0.97) and 0.82 (95% CI, 0.74-0.88), respectively. The summary diagnostic odds ratio was 102.04 (95% CI, 49.55-210.13). The area under the summary receiver operating characteristic curve was 0.97 (95% CI, 0.95-0.98). In the head-to-head comparison, CEUS showed higher diagnostic sensitivity than CECT (0.94 versus 0.85) for renal cancer, whereas the specificities were comparable between CEUS and CECT (0.77 versus 0.75).

CONCLUSIONS

Contrast-enhanced US has high sensitivity and moderate specificity in the differential diagnosis of renal cancer. The diagnostic sensitivity of CEUS in renal cancer was higher than that of CECT, suggesting that CEUS could be used as a preferred diagnostic tool for renal cancer.

[Spontaneously Resolving of Huge Simple Hepatic Cyst]

Simple hepatic cysts are common benign liver lesions that usually have no malignant capability. They are generally asymptomatic and are often found incidentally by abdominal imaging procedures. Treatment becomes necessary, however, when huge hepatic cysts cause symptoms and develop complications, such as hemorrhage, adjacent organ damage, and infection. Several therapeutic options have been performed for symptomatic and huge cysts, including the aspiration of cystic fluid, infusion of various sclerosing agents, and surgical intervention. The optimal management of huge hepatic cysts is controversial and each option has its complications and limitations. This paper reports a case of a 66-year-old woman diagnosed with a simple hepatic cyst 2 years earlier, who was referred to hospital due to abdominal pain. The diagnosis was a huge hepatic cyst with symptoms by abdominal imaging studies. During the follow-up period, the huge cysts resolved spontaneously without treatment.