European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB): An Update on the Pediatric CEUS Registry on Behalf of the "EFSUMB Pediatric CEUS Registry Working Group"

Contrast-enhanced US versus US-guided biopsy for abdominal and pelvic neoplasm in paediatric patients: a propensity score matching study

OBJECTIVE

To compare the diagnostic performance of CEUS-guided biopsy (CEUS-GB) and ultrasound-guided biopsy (US-GB) in evaluating abdominal and pelvic (abdominopelvic) neoplasms in paediatric patients.

METHODS

Patients aged < 18 years with abdominopelvic tumours who underwent either CEUS-GB or US-GB between April 2005 and May 2022 were retrospectively evaluated. Tumours diagnosed as malignancies by pathology were considered true-positive findings. Benign lesions were identified by pathology or clinical follow-up of at least 6 months. The diagnostic performance of the two groups was compared using propensity score matching (PSM). Complications were also analysed.

RESULTS

The present study included 764 paediatric patients (437 boys; median age, 24 months; interquartile range, 10-60 months); 151 were in the CEUS-GB group, and 613 were in the US-GB group. The sample adequacy rate was 100% (151 of 151) for the CEUS-GB group, which was greater than the 97.4% (597 of 613) for the US-GB group (p < 0.001). The overall diagnostic accuracy of the CEUS-GB group and US-GB group was 98.7% (149 of 151) versus 97.3% (581 of 597) in the total cohort (p = 0.551) and 98.7% (149 of 151) versus 92.7% (140 of 151) in the PSM cohort (p = 0.020). Two patients (0.3%) in the US-GB group experienced complications (Common Terminology Criteria for Adverse Events (CTCAE), grade 1-2) correlated with the biopsy. No adverse reactions occurred in the CEUS-GB group.

CONCLUSION

CEUS-GB of abdominopelvic tumours in paediatric patients is an effective and safe procedure with greater diagnostic accuracy than US-GB, especially for tumours with necrotic areas.

CLINICAL RELEVANCE STATEMENT

Contrast-enhanced US-guided biopsy of solid abdominal and pelvic tumours in paediatric patients is an effective and safe procedure with greater diagnostic accuracy than US-guided biopsy, especially for tumours with necrotic areas.

KEY POINTS

Contrast-enhanced ultrasound (CEUS) may be superior to conventional ultrasound at guiding biopsy of abdominopelvic masses in paediatric patients. CEUS-guided core needle biopsy of abdominopelvic masses in children was safe and resulted in a diagnostic yield of 98.7%. CEUS guidance should be considered in this population when colour Doppler US is unable to determine a biopsy site.

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.

Value of contrast-enhanced ultrasound for vascular diseases of the liver - current indications and open questions

Contrast-enhanced ultrasonography (CEUS) is a widely available and well-tolerated technique that can expand the diagnosis of a variety of vascular liver diseases. This paper presents an overview of the current possibilities of the use of CEUS in vascular liver diseases. Particularly where Doppler sonography has technical limitations, CEUS provides additional opportunities to visualize vascular thrombosis and other obstructions restricting blood flow. When CT or MRI contrast agents cannot be used because of severe allergy or renal insufficiency, CEUS can be a valuable diagnostic alternative and has demonstrated comparable diagnostic performance in at least some vascular liver diseases, such as portal vein thrombosis. In addition, CEUS works without radiation and, therefore, might be particularly suitable for young patients and children. This may be useful, for example, in congenital disorders such as persistent umbilical vein or preduodenal portal vein. Vascular liver disease is rare and comprehensive data are still lacking, but the available literature provides promising insights into potential new ways to study vascular liver disease. Although most studies are based on small sample sizes or even case reports, the high diagnostic utility is undisputed.

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.

The Use of Contrast-Enhanced Ultrasound (CEUS) in the Evaluation of the Neonatal Brain

In recent years, advancements in technology have allowed the use of contrast-enhanced ultrasounds (CEUS) with high-frequency transducers, which in turn, led to new possibilities in diagnosing a variety of diseases and conditions in the field of radiology, including neonatal brain imaging. CEUSs overcome some of the limitations of conventional ultrasounds (US) and Doppler USs. It allows the visualization of dynamic perfusion even in the smallest vessels in the whole brain and allows the quantitative analysis of perfusion parameters. An increasing number of articles are published on the topic of the use of CEUSs on children each year. In the area of brain imaging, the CEUS has already proven to be useful in cases with clinical indications, such as hypoxic-ischemic injuries, stroke, intracranial hemorrhages, vascular anomalies, brain tumors, and infections. We present and discuss the basic principles of the CEUS and its safety considerations, the examination protocol for imaging the neonatal brain, and current and emerging clinical applications.

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.

[Tumor predisposition syndromes and nephroblastoma : Early diagnosis with imaging]

CLINICAL/METHODICAL ISSUE

The Beckwith-Wiedemann spectrum (BWSp) as well as the WT1-related syndromes, Denys-Drash syndrome (DDS) and WAGR spectrum (Wilms tumor, Aniridia, genitourinary anomalies and a range of developmental delays) are tumor predisposition syndromes (TPS) of Wilms tumor (WT). Patients with associated TPS are at higher risk of developing chronic kidney disease and bilateral and metachronous tumors as well as nephrogenic rests.

STANDARD RADIOLOGICAL METHODS

Standard imaging diagnostics for WT include renal ultrasound and magnetic resonance imaging (MRI). In the current renal tumor studies Umbrella SIOP-RTSG 2016 and Randomet 2017, thoracic computed tomography (CT) is also recommended as standard. Positron emission tomography (PET)-CT and whole-body MRI, on the other hand, are not part of routine diagnostics.

METHODOLOGICAL INNOVATIONS

In recent publications, renal ultrasound is recommended every 3 months until the age of 7 years in cases of clinical suspicion or molecularly proven TPS.

PERFORMANCE

Patients with TPS and regular renal ultrasounds have smaller tumor volumes and lower tumor stages at WT diagnosis than patients without such a screening. This allows a reduction of therapy intensity and facilitates the performance of nephron sparing surgery, which is prognostically relevant especially in bilateral WT.

ACHIEVEMENTS

Early diagnosis of WT in the context of TPS ensures the greatest possible preservation of healthy and functional renal tissue. Standardized screening by regular renal ultrasounds should therefore be firmly established in clinical practice.

PRACTICAL RECOMMENDATIONS

The initial diagnosis of TPS is clinical and requires a skilled and attentive examiner in the presence of sometimes subtle clinical manifestations, especially in the case of BWSp. Clinical diagnosis should be followed by genetic testing, which should then be followed by sonographic screening.

Microvascular Flow Imaging: A State-of-the-Art Review of Clinical Use and Promise

Vascular imaging with color and power Doppler is a useful tool in the assessment of various disease processes. Assessment of blood flow, from infarction and ischemia to hyperemia, in organs, neoplasms, and vessels, is used in nearly every US investigation. Recent developments in this area are sensitive to small-vessel low velocity flow without use of intravenous contrast agents, known as microvascular flow imaging (MVFI). MVFI is more sensitive in detection of small vessels than color, power, and spectral Doppler, reducing the need for follow-up contrast-enhanced US (CEUS), CT, and MRI, except when arterial and venous wash-in and washout characteristics would be helpful in diagnosis. Varying clinical applications of MVFI are reviewed in adult and pediatric populations, including its technical underpinnings. MVFI shows promise in assessment of several conditions including benign and malignant lesions in the liver and kidney, acute pathologic abnormalities in the gallbladder and testes, and superficial lymph nodes. Future potential of MVFI in different conditions (eg, endovascular repair) is discussed. Finally, clinical cases in which MVFI correlated and potentially obviated additional CEUS, CT, or MRI are shown.

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.

Transfontanellar Contrast-enhanced US for Intraoperative Imaging of Cerebral Perfusion during Neonatal Arterial Switch Operation

Background Brain injury and subsequent neurodevelopmental disorders are major determinants for later-life outcomes in neonates with transposition of the great arteries (TGA). Purpose To quantitatively assess cerebral perfusion in neonates with TGA undergoing arterial switch operation (ASO) using transfontanellar contrast-enhanced US (T-CEUS). Materials and Methods In a prospective single-center cross-sectional diagnostic study, neonates with TGA scheduled for ASO were recruited from February 2018 to February 2020. Measurements were performed at five time points before, during, and after surgery (T₁-T₅), and 11 perfusion parameters were derived per cerebral hemisphere. Neonate clinical characteristics, heart rate, mean arterial pressure, central venous pressure, near-infrared spectroscopy, blood gas analyses, ventilation time, time spent in the pediatric intensive care unit, and time in hospital were correlated with imaging parameters. Analysis of variance or a mixed-effects model were used for groupwise comparisons. Results A total of 12 neonates (mean gestational age, 39 6/7 weeks ± 1/7 [SD]) were included and underwent ASO a mean of 6.9 days ± 3.4 after birth. When compared with baseline values, T-CEUS revealed a longer mean time-to-peak (right hemisphere, 4.3 seconds ± 2.1 vs 17 seconds ± 6.4 [P < .001]; left hemisphere, 4.0 seconds ± 2.3 vs 21 seconds ± 8.7 [P < .001]) and rise time (right hemisphere, 3.5 seconds ± 1.7 vs 11 seconds ± 5.1 [P = .002]; left hemisphere, 3.4 seconds ± 2.0 vs 22 seconds ± 7.8 [P = .004]) in both cerebral hemispheres during low-flow cardiopulmonary bypass and hypothermia (T₄) for all neonates. Neonate age at surgery negatively correlated with T-CEUS parameters during ASO, as calculated with the area under the flow curve (AUC) during wash-in (R = -0.60, P = .020), washout (R = -0.82, P = .002), and both wash-in and washout (R = -0.79, P = .004). Mean AUC values were lower in neonates older than 7 days compared with younger neonates during wash-in ([87 arbitrary units {au} ± 77] × 10² vs [270 au ± 164] × 10², P = .049]), washout ([15 au ± 11] × 10³ vs [65 au ± 38] × 10³, P = .020]) and both wash-in and washout ([24 au ± 18] × 10³ vs [92 au ± 53] × 10³, P = .023). Conclusion Low-flow hypothermic conditions resulted in reduced cerebral perfusion, as measured with transfontanellar contrast-enhanced US, which inversely correlated with age at surgery. Clinical trial registration no. NCT03215628 © RSNA, 2022 Online supplemental material is available for this article.

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.

Feasibility and Safety of Neonatal Brain Contrast-Enhanced Ultrasound: A Prospective Study Using MRI as Reference Standard

Background: MRI is the gold standard for neonatal brain imaging but is expensive, time-consuming, potentially limited by availability and accessibility, and may be contraindicated in some patients. Transfontanelle neonatal head ultrasound is an excellent alternative but may be less sensitive and specific than MRI. Contrast-enhanced ultrasound (CEUS) has the potential to improve ultrasound's capabilities. Objective: To prospectively evaluate the feasibility, safety, and diagnostic performance of transfontanelle neonatal brain contrast-enhanced ultrasound (CEUS), using MRI as the reference standard. Methods: Neonates in the institutional neonatal ICU undergoing MRI as part of clinical care were prospectively recruited to undergo portable brain ultrasound and CEUS for research purposes. Brain ultrasound and CEUS were performed portably, without moving the patient from the isolette or crib in the NICU. Adverse events were recorded. Two radiologists independently evaluated ultrasound and CEUS images for abnormalities and then reached consensus for discrepancies. A separate radiologist reviewed MRI examinations. Sensitivity, specificity, and inter-reader agreement were evaluated, using MRI as reference. Qualitative post hoc image review was performed. Results: Twenty-six neonates (9 boys, 17 girls; mean age 15.2 ± 14.0 days) were included. No significant alteration in patient vital signs or adverse reaction to the ultrasound contrast agent (UCA) occurred. Mean examination duration was significantly shorter for CEUS than MRI (21 ± 4.7 minutes vs 74 ± 34.8 minutes, p<.001). Inter-rater agreement for any abnormality was almost perfect for both ultrasound and CEUS (k= 0.92 and 0.85, respectively). Sensitivity for any abnormality was 86.7% for ultrasound and 93.0% for CEUS; specificity was 100.0% for both. CEUS exhibited sensitivity of 87.5% for acute or subacute ischemia and 100.0% for chronic ischemia, and specificity of 100.0% for acute or subacute ischemia and chronic ischemia. Sensitivity for subdural and intraparenchymal hemorrhage was poor (22.2%-50.0%) at both ultrasound and CEUS. Post hoc review demonstrated a case of post-ischemic hyperperfusion, confirmed by subsequent contrast-enhanced CT, on CEUS but not on MRI. Conclusion: Portable brain CEUS in neonates is feasible, safe, and more rapid than MRI. Clinical Impact: The potential diagnostic utility of brain neonatal CEUS relative to conventional ultrasound, particularly for ischemia, warrants further investigation.