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

Contrast-enhanced ultrasound of the liver: basics and interpretation of common focal lesions

Over the past 20 years, contrast-enhanced ultrasound (CEUS) has become established as a procedure that is complementary to B-mode ultrasound and color Doppler sonography.The aim of this review is to provide the fundamental knowledge required for examining the liver with CEUS. Additionally, the characteristic CEUS patterns of frequent focal liver lesions are described.Considering the limitations of ultrasound, CEUS offers an equivalent alternative to other imaging modalities, such as computed tomography and magnetic resonance imaging, for evaluating focal liver lesions. It should be utilized as a primary modality due to its lack of radiation exposure and rapid availability. KEY POINTS::   · CEUS plays an important role particularly in the detection and evaluation of incidentally detected liver lesions.. · Considering the limitations of ultrasound, CEUS offers an equivalent alternative to other imaging modalities, such as CT and MRI, for evaluating focal liver lesions.. CITATION FORMAT: · Safai Zadeh E, Prosch H, Ba-Ssalamah A et al. Contrast-enhanced ultrasound of the liver: basics and interpretation of common focal lesions. Fortschr Röntgenstr 2024; DOI: 10.1055/a-2219-4726.

Case Report: The value of contrast-enhanced ultrasound and contrast-enhanced computed tomography in the diagnosis of hepatic angiosarcoma

Background

Enhanced imaging techniques have the overwhelming advantages of being noninvasive and sensitive enough to evaluate the microcirculation of lesions, thus making them accurate in the diagnosis of hepatic lesions. Unfortunately, there is very little research on and knowledge of the imaging features of a rare cancerous condition: hepatic angiosarcoma (HA).

Case summary

In this study, we retrospectively collected the data of six patients who underwent both contrast-enhanced ultrasound (CEUS) and contrast-enhanced computed tomography (CECT), and subsequently obtained a definitive histopathologic diagnosis of HA. We described the imaging appearances of HA by comparing CEUS and CECT images. Furthermore, we analyzed these imaging characteristics from the perspective of histopathology and tumorigenesis. The study included the largest number (six) of histopathologically confirmed HA patients who had received CEUS examinations to date.

Conclusion

By offering readers comprehensive knowledge of contrast imaging, especially CEUS, in the diagnosis of HA, our study may reduce misdiagnosis and further improve treatment options.

Review on Pediatric Malignant Focal Liver Lesions with Imaging Evaluation: Part I

Malignant focal liver lesions (FLLs) are commonly reported in adults but rarely seen in the pediatric population. Due to the rarity, the understanding of these diseases is still very limited. In children, most malignant FLLs are congenital. It is very important to choose appropriate imaging examination concerning various factors. This paper will outline common pediatric malignant FLLs, including hepatoblastoma, hepatocellular carcinoma, and cholangiocarcinoma and discuss them against the background of the latest knowledge on comparable/similar tumors in adults. Medical imaging features are of vital importance for the non-invasive diagnosis and follow-up of treatment of FLLs in pediatric patients. The use of CEUS in pediatric patients for characterizing those FLLs that remain indeterminate on conventional B mode ultrasounds may be an effective option in the future and has great potential to be integrated into imaging algorithms without the risk of exposure to ionizing radiation.

Application of Quantitative Parameters of Contrast-Enhanced Ultrasound in Common Benign and Malignant Lesions in Pediatric Livers: A Preliminary Study

We aimed to investigate the diagnostic utility of quantitative parameters of contrast-enhanced ultrasound (CEUS) for benign and malignant liver lesions in pediatric patients. This was a single-center retrospective analysis of children with liver lesions who underwent CEUS at our hospital between July 2019 and February 2023. The CEUS perfusion patterns for all lesions were qualitatively analyzed using histopathology, contrast-enhanced magnetic resonance imaging, contrast-enhanced computed tomography, or long-term clinical follow-up as reference standards. The CEUS images were quantitatively analyzed using SonoLiver® software (TomTec Imaging Systems, Munich, Germany) to obtain data regarding quantitative parameters and dynamic vascular pattern (DVP) parametric images, including rise time (RT), time to peak (TTP), mean transit time (mTT), and maximum intensity (IMAX). Statistical analysis was carried out using Student's t-test and receiver operating characteristic (ROC) curve analysis to evaluate the diagnostic value of quantitative parameters. A total of 53 pediatric cases were included in this study, and 88.57% (31/35) of malignant lesions exhibited hyper-enhancement with rapid washout patterns; the same proportion of DVP parametric images exhibited washout patterns. Conversely, 94.44% (17/18) of benign lesions showed hyper-enhancement with slow washout patterns, and the same proportion of DVP parametric images showed no-washout patterns. RT, TTP, and mTT were significantly shorter in the malignant group than in the benign group (p < 0.05), while IMAX showed no significant difference (p > 0.05). ROC analysis indicated that mTT < 113.34 had the highest diagnostic value, with an area under the curve of 0.82. CEUS quantitative analysis had an accuracy of 98.11%, while qualitative analysis had an accuracy of 92.45%, with no statistically significant difference (p > 0.05). Quantitative analysis of CEUS provides valuable assistance in differentiating benign and malignant liver lesions in children. Among all quantitative parameters, mTT holds promise as a potentially valuable tool for identifying liver tumors.

Pedunculated Focal Nodular Hyperplasia: When in Doubt, Should We Cut It Out?

Focal nodular hyperplasia (FNH) is the second most common benign hepatic tumor and can rarely present as an exophytic solitary mass attached to the liver by a stalk. Most FNH cases are usually detected as incidental findings during surgery, imaging or physical examination and have a high female predominance. However, the pedunculated forms of FNH are particularly rare and commonly associated with severe complications and diagnostic challenges. Hence, our study aims to provide a comprehensive summary of the available data on the pedunculated FNH cases among adults and children. Furthermore, we will highlight the role of different therapeutic options in treating this clinical entity. The use of imaging techniques is considered a significant addition to the diagnostic toolbox. Regarding the optimal treatment strategy, the main indications for surgery were the presence of symptoms, diagnostic uncertainty and increased risk of complications, based on the current literature. Herein, we also propose a management algorithm for patients with suspected FNH lesions. Therefore, a high index of suspicion and awareness of this pathology and its life-threatening complications, as an uncommon etiology of acute abdomen, is of utmost importance in order to achieve better clinical outcomes.

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

BACKGROUND

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Comparison of the different imaging modalities used to image pediatric oncology patients: A COG diagnostic imaging committee/SPR oncology committee white paper

Diagnostic imaging is essential in the diagnosis and management, including surveillance, of known or suspected cancer in children. The independent and combined roles of the various modalities, consisting of radiography, fluoroscopy, ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine (NM), are both prescribed through protocols but also function in caring for complications that may occur during or subsequent to treatment such as infection, bleeding, or organ compromise. Use of a specific imaging modality may be based on situational circumstances such as a brain CT or MR for a new onset seizure, chest CT for respiratory signs or symptoms, or US for gross hematuria. However, in many situations, there are competing choices that do not easily lend themselves to a formulaic approach as options; these situations depend on the contributions of a variety of factors based on a combination of the clinical scenario and the strengths and limitations of the imaging modalities. Therefore, an improved understanding of the potential influence of the imaging decision pathways in pediatric cancer care can come from comparison among the individual diagnostic imaging modalities. The purpose of the following material to is to provide such a comparison. To do this, pediatric imaging content experts for the individual modalities of radiography and fluoroscopy, US, CT, MRI, and NM will discuss the individual modality strengths and limitations.

Incidental Findings in Pediatric Patients: How to Manage Liver Incidentaloma in Pediatric Patients

The World Federation for Ultrasound in Medicine and Biology (WFUMB) is addressing the issue of incidental findings (IFs) with a series of publications entitled "Incidental imaging findings-the role of ultrasound". IFs in the liver of newborns and children are rare and much less commonly encountered than in adults; as a result, they are relatively much more frequently malignant and life-threatening, even when they are of benign histology. Conventional B-mode ultrasound is the well-established first line imaging modality for the assessment of liver pathology in pediatric patients. US technological advances, resulting in image quality improvement, contrast-enhanced ultrasound (CEUS), liver elastography and quantification tools for steatosis have expanded the use of ultrasound technology in daily practice. The following overview is intended to illustrate incidentally detected liver pathology covering all pediatric ages. It aims to aid the examiner in establishing the final diagnosis. Management of incidentally detected focal liver lesions (FLL) needs to take into account the diagnostic accuracy of each imaging modality, the patient's safety issues (including ionizing radiation and nephrotoxic contrast agents), the delay in diagnosis, the psychological burden on the patient and the cost for the healthcare system. Moreover, this paper should help the pediatric clinician and ultrasound practitioner to decide which pathologies need no further investigation, which ones require interval imaging and which cases require further and immediate diagnostic procedures.

Hepatic hemangiomas in childhood: the spectrum of radiologic findings. A pictorial essay

Hepatic hemangiomas (HHs) are the most common benign liver tumors in infancy, but despite their frequent occurrence, their radiologic appearance may be particularly challenging to assess, owing to unique anatomical and development features that distinguish their subtypes in the pediatric population. There are 3 main patterns of the lesions recognized in HHs: focal, multifocal and diffuse. Medical care strategies range from simple observation to surgery, and a timely diagnosis is crucial to establish the most appropriated clinical management and therapy. Ultrasound (US) is typically the first level examination of pediatric vascular anomalies, able to meet a satisfactory diagnosis and has proved very helpful to assess for involution through serial imaging. CT and MRI are second-level methods seldom performed, offering an anatomical panoramic view and clarification when US is non-conclusive. Histologic confirmation is rarely required. HHs show a variable sonographic appearance, with hypoechoic (mostly) or hyperechoic solitary\multifocal mass and wide features. Hepatic vessels assessment reveals an abnormal flow, enlarged vasa, decreased resistive index (RI) values, scarce blood supply distally to lesions and hyper vascular regions inside them. In this pictorial essay, we review HHs subtypes in further details, illustrate US, CT and MRI findings and clarify a recurrent dispute over the existing terminology.

Microbubbles in the belly: optimizing the protocol for contrast-enhanced ultrasound of the pediatric abdomen

Intravenous contrast-enhanced ultrasound (CEUS) can serve as a diagnostic or problem-solving tool in pediatric imaging. CEUS of abdominal solid organs has been reported for a number of indications. The approach to the examination broadly falls into two categories: evaluation of a focal lesion or surveillance of an organ or organs for lesions or perfusion abnormalities. A consistent, technical imaging protocol for both of these clinical scenarios facilitates integration of routine use of CEUS in an imaging department. Here we review the CEUS imaging protocols for abdominal organs in children, including technical and solid-organ-specific considerations.

Features of Nodules in Explants of Children Undergoing Liver Transplantation for Biliary Atresia

(1) Background: In patients with biliary atresia (BA) liver nodules can be identified either by pre-transplant imaging or on the explant. This study aimed to (i) analyze the histopathology of liver nodules, and (ii) to correlate histopathology with pretransplant radiological features. (2) Methods: Retrospective analysis of liver nodules in explants of BA patients transplanted in our center (2000−2021). Correlations with pretransplant radiological characteristics, patient age at liver transplantation (LT), time from Kasai hepatoportoenterostomy (KPE) to LT, age at KPE and draining KPE. (3) Results: Of the 63 BA-patients included in the analysis, 27/63 (43%) had nodules on explants. A majority were benign macroregenerative nodules. Premalignant (low-grade and high-grade dysplastic) and malignant (hepatocellular carcinoma) nodules were identified in 6/63 and 2/63 patients, respectively. On pretransplant imaging, only 13/63 (21%) patients had liver nodules, none meeting radiological criteria for malignancy. The occurrence of liver nodules correlated with patient age at LT (p < 0.001), time KPE-LT (p < 0.001) and draining KPE (p = 0.006). (4) Conclusion: In BA patients, pretransplant imaging did not correlate with the presence of liver nodules in explants. Liver nodules were frequent in explanted livers, whereby 25% of explants harboured malignant/pre-malignant nodules, emphasizing the need for careful surveillance in BA children whose clinical course may require LT.

Contrast-enhanced US of the Liver and Kidney: A Problem-solving Modality

Contrast-enhanced US (CEUS) has an important role as a supplement to CT or MRI in clinical practice. The main established utilizations are in the liver and the kidney. The primary advantages of CEUS compared with contrast-enhanced CT or MRI relate to its superior contrast resolution, real-time continuous scanning, pure intravascular nature, portability, and safety-especially in patients with renal impairment or CT or MRI contrast agent allergy. This article focuses on the use of CEUS in the liver and kidney.

Comparison of the Balthazar score of acute pancreatitis between computed tomography and ultrasound in children: pitfalls of ultrasound in diagnosing and evaluating pancreatitis

PURPOSE

To demonstrate the utility of ultrasound for predicting the outcome of pancreatitis in pediatric patients using the Balthazar score.

METHODS

Twenty-four children diagnosed with pancreatitis, who underwent computed tomography (CT) followed by ultrasound within 24 h, were included. The Balthazar score was calculated using both modalities based on the appearance of the pancreas (score 0-4). The association between the Balthazar scores with CT and ultrasound was evaluated using single linear regression analysis. To evaluate the sonographic accuracy, the ultrasound severity index and findings were compared with those of CT. Presence or absence of abnormal pancreatic parenchymal change on ultrasound was compared to the presence or absence of pancreatic necrosis on CT. The CT and sonographic findings were evaluated in eight intra-abdominal segments.

RESULTS

The Balthazar scores yielded by CT (2.2 ± 1.1, range 0-4) and ultrasound (2.0 ± 1.1, range 0-4) showed a significantly strong correlation (r = 0.918, p < 0.001). The accuracy of ultrasound in determining the CT Balthazar scores was 91.7% (95% confidence interval 73.0-99.0%, 22/24 patients). In the two cases with pancreatic necrosis on CT, only one case was detected as abnormal pancreatic parenchymal change. Sonographic diagnostic accuracy in the pancreatic head was lower than that in the body and tail (accuracy of the pancreatic head, body, and tail enlargement/edema = 83.3%/75%, 100%/100%, and 100%/100%, respectively).

CONCLUSIONS

The total CT and ultrasound severity indices were significantly correlated. Ultrasound is a useful modality for evaluating not only the initial pancreatic condition but also the severity of pediatric pancreatitis.