Contrast-enhanced US evaluation in patients with blunt abdominal trauma()

Point of Care Abdominal Ultrasound

Abdominal pain is a common emergency department complaint, and point-of-care ultrasound (POCUS) of the abdomen is increasingly being utilized to evaluate clinical manifestations. It aids in accurate diagnoses and assists in procedures, particularly in emergency and critical care settings. Imaging is often required to confirm the etiology of abdominal pain. POCUS provides the benefit of avoiding radiation exposure and enables quicker diagnosis compared to computed tomography scans. There is growing evidence of the diagnostic accuracy for numerous abdominal POCUS applications, including appendicitis, intussusception, diverticulitis, gastric ultrasound and contrast-enhanced ultrasound.

Progress in the Application of Portable Ultrasound Combined with Artificial Intelligence in Pre-Hospital Emergency and Disaster Sites

With the miniaturization of ultrasound and the development of artificial intelligence, its application in disaster scenes and pre-hospital emergency care has become more and more common. This study summarizes the literature on portable ultrasound in pre-hospital emergency and disaster scene treatment in the past decade and reviews the development and application of portable ultrasound. Portable ultrasound diagnostic equipment can be used to diagnose abdominal bleeding, limb fracture, hemopneumothorax, pericardial effusion, etc., based on which trauma can be diagnosed pre-hospital and provide guiding suggestions for the next triage and rescue; in early rescue, portable ultrasound can guide emergency operations, such as tracheal intubation, pericardial cavity puncture, and thoracic and abdominal puncture as well as improve the accuracy and timeliness of operation techniques. In addition, with the development of artificial intelligence (AI), AI-assisted diagnosis can improve the diagnosis level of ultrasound at disaster sites. The portable ultrasound diagnosis system equipped with an AI robotic arm can maximize the pre-screening classification and fast and concise diagnosis and treatment of batch casualties, thus providing a reliable basis for batch casualty classification and evacuation at disaster accident sites.

Is it time to re-think FAST? A systematic review and meta-analysis of Contrast-Enhanced Ultrasound (CEUS) and conventional ultrasound for initial assessment of abdominal trauma

BACKGROUND

The Focused Assessment with Sonography for Trauma (FAST) examination using conventional ultrasound has limited utility for detecting solid organ injury. Therefore, this systematic review and meta-analysis compares the performance of contrast-enhanced ultrasound (CEUS) to conventional ultrasound when used as the initial assessment for abdominal trauma prior to computed tomography (CT) imaging.

METHODS

A systematic literature search of major databases was conducted of human studies investigating the diagnostic accuracy of conventional ultrasound and CEUS occurring prior to CT imaging for abdominal trauma. The study followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. The quality of studies was evaluated using the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2) tool. Paired pooled sensitivity and specificity between conventional ultrasound and CEUS were compared using data extracted from the eligible studies. Diagnostic odds ratio, number needed to diagnose values, and likelihood ratios were also determined.

RESULTS

Ten studies were included. More than half of the included studies demonstrated low risk of bias. Using McNemar's test to assess for paired binary observations, we found that CEUS had statistically higher sensitivity (0.933 vs. 0.559; two-tailed, P < 0.001) and specificity (0.995 vs. 0.979; two-tailed, P < 0.001) than conventional ultrasound in the setting of abdominal trauma, respectively. When divided into particular findings of clinical interest, CEUS had statistically higher sensitivity than conventional ultrasound in screening for active bleeding and injuries to all abdominal solid organs. CEUS also had superior diagnostic odds ratios, number needed to diagnose values, and likelihood ratios than conventional ultrasound.

CONCLUSION

The diagnostic value of CEUS was higher than that of conventional ultrasound for differentiating traumatic abdominal injuries when used as the initial assessment in the emergency department.

Role of Contrast Enhanced Ultrasound (CEUS) in the Paediatric Population with Blunt Abdominal Trauma: A Prospective Study from a Single Center Experience for Paediatric Blunt Abdominal Trauma

Aim:The aim of our study is to evaluate the diagnostic ability of contrast-enhanced ultrasonography (CEUS) in pediatric population with history of blunt abdominal trauma (BAT). Materials and methods: In an eight-year period (1/2012-1/2020), fifty-nine children (4-14 years old) were transferred to the Emergency Department with referred BAT. The initial imaging method was ultrasound scan (US). Thirty-two children were discharged in good condition 24 hours after their admission. The remaining 27, who had moderate to severe injuries and according to their laboratory tests and US results, were evaluated with CEUS and contrast-enhanced computed tomography (CECT). Results:Five children were confirmed with splenic injury, two with liver lacerations, one with liver lacerations and right kidney contusion, while in nineteen, no visceral pathology was found by US, CEUS and CECT. The CEUS and CECT were in complete agreement. On the contrary, unenhanced-US showed free peritoneal fluid in eleven children and possible parenchymal lesions in two children. In two of the patients with negative US-study, splenic contusions in CECT and CEUS were revealed. The CEUS study was also used as a follow-up method. Among the 27 patients, there were no adverse reactions from the CEUS contrast agent either at one-week and six-month follow-up, or after one-year period. Conclusion:Contrast-enhanced ultrasonography is an effective, easily performed, low cost and radiation free imaging method. It is ideal for both initial and follow up evaluation of trauma and thus, we encourage its usage in paediatric BAT cases.

Contrast-enhanced ultrasound of blunt abdominal trauma in children

Trauma is the leading cause of morbidity and mortality in children, and rapid identification of organ injury is essential for successful treatment. Contrast-enhanced ultrasound (CEUS) is an appealing alternative to contrast-enhanced CT in the evaluation of children with blunt abdominal trauma, mainly with respect to the potential reduction of population-level exposure to ionizing radiation. This is particularly important in children, who are more vulnerable to the hazards of ionizing radiation than adults. CEUS is useful in hemodynamically stable children with isolated blunt low- to moderate-energy abdominal trauma to rule out solid organ injuries. It can also be used to further evaluate uncertain contrast-enhanced CT findings, as well as in the follow-up of conservatively managed traumatic injuries. CEUS can be used to detect abnormalities that are not apparent by conventional US, including infarcts, pseudoaneurysms and active bleeding. In this article we present the current experience from the use of CEUS for the evaluation of pediatric blunt abdominal trauma, emphasizing the examination technique and interpretation of major abnormalities associated with injuries in the liver, spleen, kidneys, adrenal glands, pancreas and testes. We also discuss the limitations of the technique and offer a review of the major literature on this topic in children, including an extrapolation of experience from adults.

Starting a pediatric contrast ultrasound service: made simple!

The addition of contrast US to an existing pediatric US service requires several preparatory steps. This overview provides a guide to simplify the process. Initially, it is important to communicate to all stakeholders the justifications for pediatric contrast US, including (1) its comparable or better diagnostic results relative to other modalities; (2) its reduction in procedural sedation or anesthesia by avoiding MRI or CT; (3) its reduction or elimination of radiation exposure by not having to perform fluoroscopy or CT; (4) the higher safety profile of US contrast agents (UCA) compared to other contrast agents; (5) the improved exam comfort and ease inherent to US, leading to better patient and family experience, including bedside US exams for children who cannot be transported; (6) the need for another diagnostic option in light of increasing demand by parents and providers; and (7) its status as an approved and reimbursable exam. It is necessary to have an UCA incorporated into the pharmacy formulary noting that only SonoVue/Lumason is currently approved for pediatric use. In the United States this UCA is approved for intravenous administration for cardiac and liver imaging and for vesicoureteric reflux detection with intravesical application. In Europe and China it is only approved for the intravesical use in children. All other applications are off-label. The US scanner needs to be equipped with contrast-specific software. The UCA has to be prepared just before the exam and it is important to strictly follow the steps as outlined in the packaging inserts in order to prevent premature destruction of the microbubbles. The initial training in contrast US is best focused on the frontline staff actually performing the US studies; these might be sonographers, pediatric or interventional radiologists, or trainees. It is important from the outset to educate the referring physicians about contrast US. It is helpful to participate in existing contrast US courses, particularly those with hands-on components.

Conventional Ultrasound and Contrast-Enhanced Ultrasound in the Diagnosis of Splenic Diseases: A Systematic Review and Meta-analysis

Accurate diagnosis of splenic diseases is important for timely and accurate treatment. The objective of this study was to compare the accuracy of contrast-enhanced ultrasound (CEUS) and conventional ultrasound (US) in detecting splenic lesions. A systematic literature search was undertaken, and 8 studies met the inclusion criteria. The sensitivity and specificity of the consolidated results of CEUS were 0.95 (95% confidence interval [CI], 0.92-0.97) and 0.97 (95% CI, 0.90-0.99), respectively (I² = 27.4%; area under the curve [AUC] from a summary receiver operating characteristic curve = 0.97). The sensitivity and specificity of the consolidated results of conventional US were 0.70 (95% CI, 0.56-0.80) and 0.96 (95% CI, 0.76-0.99; I² = 83.4%; AUC = 0.84). In this systematic review and meta-analysis, the sensitivity and specificity of CEUS were higher than those of conventional US in diagnosing splenic lesions. Contrast-enhanced US is a promising method for accurately diagnosing splenic lesions.

Contrast-enhanced ultrasonography (CEUS) in the follow-up of pediatric abdominal injuries: value and timing

AIMS

Primary aim was to investigate the value and safety of contrast-enhanced ultrasonography (CEUS) during follow-up (FU) of splenic, hepatic and renal post-traumatic injuries in a pediatric population. Secondary aim was to extrapolate appropriate timing of FU-CEUS.

METHODS

In a retrospective study, post-traumatic parenchymal injuries diagnosed with CT or CEUS, were subjected to non-operative management and followed with CEUS.

RESULTS

Forty-six patients were enrolled, with isolated or combined injuries, for a total of 30 splenic, 15 hepatic and 12 renal injuries. At admission 42/46 patients underwent CT and 4/46 underwent CEUS. During FU a total of 65 CEUS were performed: 16 within 72 h to check delayed active bleeding or parenchymal rupture; 24 between 5 and 10 days post admission, to pose indication to active mobilization or to discharge; 21 between 20 and 60 days post admission to document complete healing of the lesion or pose indication to discharge in most severe injuries. No complications related to CEUS were encountered.

CONCLUSIONS

CEUS is valuable and safe to follow patients with post-traumatic abdominal injuries, even if further data are needed for renal injuries. We propose a tailored approach based on injury grade and clinical course: in the first 3 days only in case of delayed bleeding or rupture suspect; between 5 and 10 days post trauma to ensure a safe active mobilization and/or pose indication to discharge, and over 20-30 days post trauma to pose indication to discharge in most severe injuries or document complete healing and permit return to sport activities.

Duodeno-pancreatic and extrahepatic biliary tree trauma: WSES-AAST guidelines

Duodeno-pancreatic and extrahepatic biliary tree injuries are rare in both adult and pediatric trauma patients, and due to their anatomical location, associated injuries are very common. Mortality is primarily related to associated injuries, but morbidity remains high even in isolated injuries. Optimal management of duodeno-bilio-pancreatic injuries is dictated primarily by hemodynamic stability, clinical presentation, and grade of injury. Endoscopic and percutaneous interventions have increased the ability to non-operatively manage these injuries. Late diagnosis and treatment are both associated to increased morbidity and mortality. Sequelae of late presentations of pancreatic injury and complications of severe pancreatic trauma are also increasingly addressed endoscopically and with interventional radiology procedures. However, for moderate and severe extrahepatic biliary and severe duodeno-pancreatic injuries, immediate operative intervention is preferred as associated injuries are frequent and commonly present with hemodynamic instability or peritonitis. The aim of this paper is to present the World Society of Emergency Surgery (WSES) and American Association for the Surgery of Trauma (AAST) duodenal, pancreatic, and extrahepatic biliary tree trauma management guidelines.

Kidney and uro-trauma: WSES-AAST guidelines

Renal and urogenital injuries occur in approximately 10-20% of abdominal trauma in adults and children. Optimal management should take into consideration the anatomic injury, the hemodynamic status, and the associated injuries. The management of urogenital trauma aims to restore homeostasis and normal physiology especially in pediatric patients where non-operative management is considered the gold standard. As with all traumatic conditions, the management of urogenital trauma should be multidisciplinary including urologists, interventional radiologists, and trauma surgeons, as well as emergency and ICU physicians. The aim of this paper is to present the World Society of Emergency Surgery (WSES) and the American Association for the Surgery of Trauma (AAST) kidney and urogenital trauma management guidelines.

Clinical use of contrast-enhanced ultrasound beyond the liver: a focus on renal, splenic, and pancreatic applications

Contrast-enhanced ultrasound (CEUS) is a relatively novel, but increasingly used, diagnostic imaging modality. In recent years, due to its safety, quickness, and repeatability, several studies have demonstrated the accuracy, specificity, and sensitivity of CEUS. The European Federation of Societies for Ultrasound in Medicine and Biology has recently updated the previous guidelines from 2012 for the use of CEUS in non-hepatic applications. This review deals with the clinical use and applications of CEUS for the evaluation of non-hepatic abdominal organs, focusing on renal, splenic, and pancreatic applications.

Contrast-enhanced ultrasound (CEUS) in pediatric blunt abdominal trauma

Baseline ultrasound is the first-choice technique in traumatic hemodynamically stable children, and is essential in the early assessment of unstable patients to detect hemoperitoneum or other potentially fatal conditions. Despite the technological advancements in new ultrasound equipment and the experience of the operators, it is not always possible to rule out the presence of parenchymal traumatic lesions by means of baseline ultrasound nor to suspect them, especially in the absence of hemoperitoneum. For this reason, in the last decades, basic ultrasound has been associated with contrast-enhanced ultrasound (CEUS) to evaluate the stable little patient in cases such as low-energy blunt abdominal trauma. Because it relies on second-generation contrast agents, the CEUS technique allows for better detection of parenchymal injuries. CEUS has been demonstrated to be almost as sensitive as contrast-enhanced CT in the detection of traumatic injuries in patients affected by low-energy isolated abdominal trauma, with levels of sensitivity and specificity up to 95%. A very important point in favor of CEUS is its capacity to help distinguish the healthy patient, who can be discharged, from the one needing prolonged monitoring, operative management or hospitalization. Finally, we also have the ability to follow-up on low-grade traumatic lesions using CEUS, always keeping in mind patients' clinical conditions and their hemodynamics.

Pediatric ultrasonography of the pancreas: normal and abnormal findings

The pancreas is easily investigated in children thanks to the relative lack of fat tissue and the large left hepatic lobe with an optimal acoustic window. The use of high frequency, even linear transducers, usually results in detailed images of all pancreatic areas. A wide spectrum of pancreatic pathologic conditions can be identified and monitored at ultrasound although they are relatively uncommon during childhood compared to the adult. In this paper we briefly review the anatomy, technique, and sonographic aspects of normal and pathological pediatric pancreas.

Point-of-care ultrasonography for diagnosing thoracoabdominal injuries in patients with blunt trauma

BACKGROUND

Point-of-care sonography (POCS) has emerged as the screening modality of choice for suspected body trauma in many emergency departments worldwide. Its best known application is FAST (focused abdominal sonography for trauma). The technology is almost ubiquitously available, can be performed during resuscitation, and does not expose patients or staff to radiation. While many authors have stressed the high specificity of POCS, its sensitivity varied markedly across studies. This review aimed to compile the current best evidence about the diagnostic accuracy of POCS imaging protocols in the setting of blunt thoracoabdominal trauma.

OBJECTIVES

To determine the diagnostic accuracy of POCS for detecting and excluding free fluid, organ injuries, vascular lesions, and other injuries (e.g. pneumothorax) compared to a diagnostic reference standard (i.e. computed tomography (CT), magnetic resonance imaging (MRI), thoracoscopy or thoracotomy, laparoscopy or laparotomy, autopsy, or any combination of these) in patients with blunt trauma.

SEARCH METHODS

We searched Ovid MEDLINE (1946 to July 2017) and Ovid Embase (1974 to July 2017), as well as PubMed (1947 to July 2017), employing a prospectively defined literature and data retrieval strategy. We also screened the Cochrane Library, Google Scholar, and BIOSIS for potentially relevant citations, and scanned the reference lists of full-text papers for articles missed by the electronic search. We performed a top-up search on 6 December 2018, and identified eight new studies which may be incorporated into the first update of this review.

SELECTION CRITERIA

We assessed studies for eligibility using predefined inclusion and exclusion criteria. We included either prospective or retrospective diagnostic cohort studies that enrolled patients of any age and gender who sustained any type of blunt injury in a civilian scenario. Eligible studies had to provide sufficient information to construct a 2 x 2 table of diagnostic accuracy to allow for calculating sensitivity, specificity, and other indices of diagnostic test accuracy.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles, abstracts, and full texts of reports using a prespecified data extraction form. Methodological quality of individual studies was rated by the QUADAS-2 instrument (the revised and updated version of the original Quality Assessment of Diagnostic Accuracy Studies list of items). We calculated sensitivity and specificity with 95% confidence intervals (CI), tabulated the pairs of sensitivity and specificity with CI, and depicted these estimates by coupled forest plots using Review Manager 5 (RevMan 5). For pooling summary estimates of sensitivity and specificity, and investigating heterogeneity across studies, we fitted a bivariate model using Stata 14.0.

MAIN RESULTS

We included 34 studies with 8635 participants in this review. Summary estimates of sensitivity and specificity were 0.74 (95% CI 0.65 to 0.81) and 0.96 (95% CI 0.94 to 0.98). Pooled positive and negative likelihood ratios were estimated at 18.5 (95% CI 10.8 to 40.5) and 0.27 (95% CI 0.19 to 0.37), respectively. There was substantial heterogeneity across studies, and the reported accuracy of POCS strongly depended on the population and affected body area. In children, pooled sensitivity of POCS was 0.63 (95% CI 0.46 to 0.77), as compared to 0.78 (95% CI 0.69 to 0.84) in an adult or mixed population. Associated specificity in children was 0.91 (95% CI 0.81 to 0.96) and in an adult or mixed population 0.97 (95% CI 0.96 to 0.99). For abdominal trauma, POCS had a sensitivity of 0.68 (95% CI 0.59 to 0.75) and a specificity of 0.95 (95% CI 0.92 to 0.97). For chest injuries, sensitivity and specificity were calculated at 0.96 (95% CI 0.88 to 0.99) and 0.99 (95% CI 0.97 to 1.00). If we consider the results of all 34 included studies in a virtual population of 1000 patients, based on the observed median prevalence (pretest probability) of thoracoabdominal trauma of 28%, POCS would miss 73 patients with injuries and falsely suggest the presence of injuries in another 29 patients. Furthermore, in a virtual population of 1000 children, based on the observed median prevalence (pretest probability) of thoracoabdominal trauma of 31%, POCS would miss 118 children with injuries and falsely suggest the presence of injuries in another 62 children.

AUTHORS' CONCLUSIONS

In patients with suspected blunt thoracoabdominal trauma, positive POCS findings are helpful for guiding treatment decisions. However, with regard to abdominal trauma, a negative POCS exam does not rule out injuries and must be verified by a reference test such as CT. This is of particular importance in paediatric trauma, where the sensitivity of POCS is poor. Based on a small number of studies in a mixed population, POCS may have a higher sensitivity in chest injuries. This warrants larger, confirmatory trials to affirm the accuracy of POCS for diagnosing thoracic trauma.

Role of contrast-enhanced ultrasound (CEUS) in the diagnosis and management of traumatic splenic injuries

Splenic injuries are common emergencies in the setting of abdominal trauma, as the spleen is the second most frequently injured abdominal organ after the liver. The treatment of splenic injuries underwent a severe shift from operative to non-operative due to an increased awareness of the double physiological function, both immunological and hematological, of the spleen. This, in turn, led to an increased application of splenic preservation techniques. The non-operative approach has been strengthened through radiological imaging and interventional radiology. While multidetector computed tomography is mandatory in the evaluation of hemodynamically stable patients after high-energy trauma, one ultrasound (US) can be used as a first-line technique to examine patients in cases of low-energy trauma. Unfortunately, baseline US has low sensitivity in the detection of traumatic injuries. With the introduction of contrast-enhanced ultrasound (CEUS) as a reliable alternative to baseline ultrasound for low-grade abdominal trauma, the sensitivity of the US technique in recognizing traumatic abdominal lesions has strongly increased, reaching levels of accuracy similar to those of the CT. It has also been strongly recommended for use with children, as it allows for the performance of imaging techniques with the lowest dose of radiation possible. In this review, the authors aim to present the typical appearance of traumatic splenic injuries, using enhanced CEUS capability to overcome baseline US limits, and to describe the different techniques applied according to the hemodynamic stability of the patient.

Point-of-Care Ultrasound in Trauma

The use of point-of-care ultrasound in trauma is widespread. Focused Assessment with Sonography for Trauma examination is a prototypical bedside examination used by the treating provider to quickly determine need for intervention and appropriate patient disposition. The role of bedside ultrasound in trauma, however, has expanded beyond the Focused Assessment with Sonography for Trauma examination. Advancements in diagnostics include contrast-enhanced ultrasound, thoracic, and musculoskeletal applications. Ultrasound is also an important tool for trauma providers for procedural guidance including vascular access and regional anesthesia. Its portability, affordability, and versatility have made ultrasound an invaluable tool in trauma management in resource-limited settings. In this review, we discuss these applications and the supporting evidence for point-of-care ultrasound in trauma.

Contrast enhanced ultrasound for the evaluation of blunt pediatric abdominal trauma

INTRODUCTION

Blunt abdominal trauma is a common problem in children. Computed tomography (CT) is the gold standard for imaging in pediatric blunt abdominal trauma, however up to 50% of CTs are normal and CT carries a risk of radiation-induced cancer. Contrast enhanced ultrasound (CEUS) may allow accurate detection of abdominal organ injuries while eliminating exposure to ionizing radiation.

METHODS

Children aged 7-18years with a CT-diagnosed abdominal solid organ injury underwent grayscale/power Doppler ultrasound (conventional US) and CEUS within 48h of injury. Two blinded radiologists underwent a brief training in CEUS and then interpreted the CEUS images without patient interaction. Conventional US and CEUS images were compared to CT for the presence of injury and, if present, the injury grade. Patients were monitored for contrast-related adverse reactions.

RESULTS

Twenty one injured organs were identified by CT in eighteen children. Conventional US identified the injuries with a sensitivity of 45.2%, which increased to 85.7% using CEUS. The specificity of conventional US was 96.4% and increased to 98.6% using CEUS. The positive predictive value increased from 79.2% to 94.7% and the negative predictive value from 85.3% to 95.8%. Two patients had injuries that were missed by both radiologists on CEUS. In a 100kg, 17year old female, a grade III liver injury was not seen by either radiologist on CEUS. Her accompanying grade I kidney injury was not seen by one of the radiologist on CEUS. The second patient, a 16year old female, had a grade III splenic injury that was missed by both radiologists on CEUS. She also had an adjacent grade II kidney injury that was seen by both. Injuries, when noted, were graded within 1 grade of CT 33/35 times with CEUS. There were no adverse reactions to the contrast.

CONCLUSION

CEUS is a promising imaging modality that can detect most abdominal solid organ injuries in children while eliminating exposure to ionizing radiation. A multicenter trial is warranted before widespread use can be recommended.

LEVEL OF EVIDENCE

Level II; Diagnostic Prospective Study.

Diagnostic accuracy of contrast enhanced ultrasound in patients with blunt abdominal trauma presenting to the emergency department: a systematic review and meta-analysis

We aimed to investigate the diagnostic accuracy of contrast-enhanced ultrasound (CEUS) in evaluating blunt abdominal trauma for patients presenting to the emergency department. Electronic search of Scopus and Pubmed was performed from inception to September 2016. Human studies investigating the diagnostic accuracy of CEUS in identifying abdominal solid organ injuries were included. Risk of bias was assessed using the QUADAS tool. A total of 10 studies were included in the study and 9 of them were included for meta-analysis. The log(DOR) values ranged from 3.80 (95% CI: 2.81-4.79) to 8.52 (95% CI: 4.58-12.47) in component studies. The combined log(DOR) was 6.56 (95% CI: 5.66-7.45). The Cochran's Q was 11.265 (p = 0.793 with 16 degrees of freedom), and the Higgins' I² was 0%. The CEUS had a sensitivity of 0.981 (95% CI: 0.868-0.950) and a false positive rate of 0.018 (95% CI: 0.010-0.032) for identifying parenchymal injuries, with an AUC of 0.984. CEUS performed at emergency department had good diagnostic accuracy in identifying abdominal solid organ injuries. CEUS can be recommended in monitoring solid organ injuries, especially for patients managed with non-operative strategy.

Clinical Applications of Contrast-Enhanced Ultrasound in the Pediatric Work-Up of Focal Liver Lesions and Blunt Abdominal Trauma: A Systematic Review

In pediatrics ultrasound has long been viewed more favorably than imaging that exposes patients to radiation and iodinated contrast or requires sedation. It is child-friendly and diagnostic capabilities have been improved with the advent of contrast-enhanced ultrasound (CEUS). The application of CEUS is indeed promising. However, no ultrasound contrast agent manufactured today is registered for pediatric use in Europe. The contrast agent SonoVue^® has recently been approved by the FDA under the name of Lumason^® to be used in hepatic investigations in adults and children. This article reviews the literature with respect to 2 specific applications of CEUS in children: 1) identification of parenchymal injuries following blunt abdominal trauma, and 2) classification of focal liver lesions. Applications were chosen through the CEUS guidelines published by the European Federation of Societies for Ultrasound in Medicine and Biology and World Federation for Ultrasound in Medicine and Biology. Literature was obtained by searching Medline and Pubmed Central (using Pubmed), Scopus database and Embase. CEUS proved to be an effective investigation in the hemodynamically stable child for identifying parenchymal injuries and for the characterization of focal liver lesions. CEUS showed comparable performance to CT and MRI with a specificity of 98% for identifying benign lesions and a negative predictive value of 100%. For the applications reviewed here, CEUS holds promising perspectives and can help reduce radiation exposure and use of iodinated contrast agents in pediatrics, thereby potentially reducing complications in routine imaging.

Pediatric adrenal trauma: evaluation and follow-up with contrast-enhanced ultrasound (CEUS)

Adrenal trauma is rarely encountered in the pediatric population, often as a component of multi-organ injury and often presenting with hematoma formation. Contrast-enhanced computed tomography (CECT) is the established imaging modality both for initial evaluation and follow-up of patients with blunt abdominal trauma. In children, radiation exposure should be minimized and alternative imaging strategies are needed. Contrast-enhanced ultrasound (CEUS) has recently been successfully used for evaluation of patients with hepatic, renal and splenic injury. We present three cases of children with post-traumatic adrenal hematomas, which were initially diagnosed with CECT and subsequently followed up with CEUS, suggesting that CEUS may be considered for follow-up of adrenal injuries in children. CEUS improves the diagnostic capabilities by increasing tissue contrast and spatial resolution, readily differentiating viable from necrotic tissue in comparison to conventional ultrasound without the risk of iodine contrast agents and ionizing radiation of repeated CECT examinations.

Diagnostic imaging of blunt abdominal trauma in pediatric patients

Trauma is a leading cause of morbidity and mortality in childhood, and blunt trauma accounts for 80-90 % of abdominal injuries. The mechanism of trauma is quite similar to that of the adults, but there are important physiologic differences between children and adults in this field, such as the smaller blood vessels and the high vasoconstrictive response, leading to the spreading of a non-operative management. The early imaging of children undergoing a low-energy trauma can be performed by CEUS, a valuable diagnostic tool to demonstrate solid organ injuries with almost the same sensitivity of CT scans; nevertheless, as for as urinary tract injuries, MDCT remains still the technique of choice, because of its high sensitivity and accuracy, helping to discriminate between an intra-peritoneal form a retroperitoneal urinary leakage, requiring two different managements. The liver is the most common organ injured in blunt abdominal trauma followed by the spleen. Renal, pancreatic, and bowel injuries are quite rare. In this review we present various imaging findings of blunt abdominal trauma in children.

Growing indications for CEUS: The kidney, testis, lymph nodes, thyroid, prostate, and small bowel

Contrast enhanced ultrasonography (CEUS) is increasingly used for non-hepatic applications as well, so that nearly all organs have been investigated. Among them, there is a growing clinical use for a variety of pathologies of the kidney, testis, and small bowel. The possibility to differentiate benign from malignant nodes in cancer patients has been investigated. A new application is in the detection of sentinel nodes after intradermal microbubble injection. The need to distinguish thyroid nodules eligible for fine needle aspiration cytology has led to the use of CEUS in thyroid examinations as well. The potential of CEUS for prostate cancer detection has been extensively investigated, with encouraging initial results. Early promise, however, has not been fulfilled. New perspective regards evaluation of the extent of prostate tissue devascularization following ablative treatments.

Blunt abdominal trauma: role of contrast-enhanced ultrasound (CEUS) in the detection and staging of abdominal traumatic lesions compared to US and CE-MDCT

PURPOSE

This study was undertaken to evaluate the accuracy of contrast-enhanced ultrasound (CEUS) in the detection and grading of abdominal traumatic lesions in patients with low-energy isolated abdominal trauma in comparison with baseline ultrasound (US) and contrast-enhanced multidetector computed tomography (CE-MDCT), considered the gold standard.

MATERIALS AND METHODS

A total of 256 consecutive patients who arrived in our Emergency Department between January 2006 and December 2012 (159 males and 97 females aged 7-82 years; mean age 41 years), with a history of low-energy isolated abdominal trauma were retrospectively analysed. All patients underwent US, CEUS with the use of a second-generation contrast agent (Sonovue, Bracco, Milan, Italy) and MDCT. Sensitivity, specificity, positive and negative predictive values (PPV and NPV) and overall accuracy for the detection of lesions and free peritoneal fluid on US and CEUS, and sensitivity for the grading of lesions on CEUS were calculated compared with the CT findings, in accordance with the American Association for the Surgery of Trauma criteria.

RESULTS

CE-MDCT identified 84 abdominal traumatic lesions (liver = 28, spleen = 35, kidney = 21) and 45 cases of free intraperitoneal fluid. US depicted 50/84 traumatic lesions and 41/45 cases of free peritoneal fluid; CEUS identified 81/84 traumatic lesions and 41/45 free peritoneal fluid. The sensitivity, specificity, PPV, NPV and overall accuracy for the identification of traumatic abdominal lesions were 59, 99, 98, 83 and 86 %, respectively, for US and 96, 99, 98, 98 and 98 %, respectively, for CEUS. The values for the identification of haemoperitoneum were 91, 99, 95, 98 and 97 %, respectively, for US and 95, 99, 95, 99 and 98 %, respectively, for CEUS. CEUS successfully staged 72/81 traumatic lesions with a sensitivity of 88 %.

CONCLUSIONS

In patients with low-energy isolated abdominal trauma US should be replaced by CEUS as the first-line approach, as it shows a high sensitivity both in lesion detection and grading. CE-MDCT must always be performed in CEUS-positive patients to exclude active bleeding and urinomas.