The use of contrast-enhanced ultrasound in blunt abdominal trauma: advantages and limitations

Diagnostic value of enhanced-contrast ultrasound for cesarean scar pregnancy: A systematic review

BACKGROUND

Cesarean scar pregnancy, an uncommon ectopic pregnancy in which the embryo is implanted in the cesarean scar, poses significant risks without prompt diagnosis and treatment. Its prevalence has risen alongside increased cesarean section rates. Despite various treatment approaches, consensus remains elusive. Ultrasonography, particularly contrast-enhanced ultrasonography, shows promise in cesarean scar pregnancy diagnosis.

MAIN BODY

This systematic review, following PRISMA guidelines, explores contrast-enhanced ultrasound's diagnostic potential in cesarean scar pregnancy. We searched PubMed, Scopus, Web of Science, and Google Scholar up to August 2023. Selection involved two stages: title/abstract screening and full-text assessment. The included studies investigated contrast-enhanced ultrasound's diagnostic value in cesarean scar pregnancy, provided adequate data, and were peer-reviewed in English. Quality assessment followed the QUADAS-2 criteria. We extracted the diagnostic accuracy metrics: sensitivity, specificity, and accuracy. Out of 193 records, five studies met the inclusion criteria (2016-2020, China). Contrast-enhanced ultrasound displayed sensitivities of 77%-100% and specificities of 95%-100%. Two studies reported accuracy of 96.9%-97.8%. Compared with conventional ultrasound, contrast-enhanced ultrasound exhibited superior sensitivity, specificity, and accuracy. It also outperformed transvaginal ultrasound.

CONCLUSION

Enhanced-contrast ultrasound holds promise for diagnosing and managing cesarean scar pregnancy by visualizing scar vascularization in real-time, thereby reducing severe complication risks. This review highlights contrast-enhanced ultrasound as a transformative diagnostic tool for cesarean scar pregnancy management, despite existing evidence limitations.

Spread and feasibility of non-operative management (NOM) of traumatic splenic injuries in adults: a national survey

In hemodynamically stable adults sustaining a splenic trauma, non-operative management (NOM) represents the standard approach even in high-severity injuries. However, knowledge, structural, and logistic limitations still reduce its wider diffusion. This study aims to identify such issues to promote the safe and effective management of these injuries.A survey was developed using the SurveyMonkey® software and spread nationally in Italy. The survey was structured into: (1) Knowledge of classification systems; (2) Availability to refer patients; (3) Patients monitoring and follow-up; (4) Center-related.The survey was filled in by 327 surgeons, with a completeness rate of 63%. Three responders out of four are used to manage trauma patients. Despite most responders knowing the existing classifications, their use is still limited in daily practice. If a patient needs to be centralized, the concern about possible clinical deterioration represent the main obstacle to achieving a NOM. The lack of protocols does not allow standardization of patient surveillance according to the degree of injury. The imaging follow-up is not standardized as well, varying between computed tomography, ultrasound, and contrast-enhanced ultrasound.The classification systems need to be spread to all the trauma-dedicated physicians, to speak a common language. A more rational centralization of patients should be promoted, ideally through agreements between peripheral and reference centers, both at regional and local level. Standardized protocols need to be shared nationally, as well as the clinical and imaging follow-up criteria should be adapted to the local features.

The value of contrast-enhanced ultrasound in vascular injury from blunt abdominal trauma in solid organs: Comparison with multidetector computed tomography using angiography as the reference standard

To evaluate the accuracy of contrast-enhanced ultrasound (CEUS) for assessing vascular injury from blunt abdominal trauma in solid organs using angiography as the reference standard and to compare it with contrast-enhanced multidetector computed tomography (MDCT). Forty-nine patients with 52 blunt abdominal trauma lesions who underwent CEUS, MDCT, and angiography were enrolled in this retrospective study. Injuries included the liver (n = 23), kidney (n = 10), and spleen (n = 19). Vascular injury in solid organs was classified into 3 types: isolated pseudoaneurysm, pseudoaneurysm with low-velocity extravasation, and active bleeding. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of CEUS and MDCT for the detection and classification of vascular injury in solid organs were calculated based on angiography. The receiver operating characteristic curve analysis of each test was performed and compared. Thirty-nine vascular injuries in solid organs were detected and classified into 9 isolated pseudoaneurysms, 9 pseudoaneurysms with low-velocity extravasation, and 21 active bleeding based on angiography as the reference standard. The sensitivity, specificity, PPV, NPV, and accuracy for bleeding detection were 97.44%, 100.00%, 100.00%, 92.86%, and 98.08%, respectively, for CEUS and MDCT. The sensitivity, specificity, PPV, NPV, and accuracy of classification (isolated pseudoaneurysm vs. pseudoaneurysm with low-velocity extravasation or active bleeding) of bleeding were 96.67%, 87.50%, 96.67%, 87.50%, and 94.74%, respectively, for CEUS and 100.00%, 75.00%, 93.75%, 100.00%, and 94.74%, respectively, for MDCT. The area under the receiver operating characteristic curves of CEUS and MDCT for bleeding detection was 0.987, and the area under the receiver operating characteristic curves for CEUS and MDCT bleeding classification were 0.921 and 0.875, respectively. CEUS and MDCT exhibited comparable consistency with angiography for detecting and classifying vascular injury from blunt abdominal trauma in solid organs. Therefore, CEUS may be an accurate and rapid imaging tool to detect bleeding and determine the need for transcatheter arterial embolization. We suggest that CEUS could be considered a first-line approach during the preparation time before MDCT to determine the appropriate management for blunt abdominal trauma.

Patients with severe polytrauma: management and imaging protocols

Traumatic injuries can be severe and complex, requiring the coordinated efforts of a multidisciplinary team. Imaging tests play a fundamental role in rapid and accurate diagnosis. In particular, whole-body computed tomography (CT) has become a key tool. There are different CT protocols depending on the patient's condition; whereas dose-optimized protocols can be used in stable patients, time/precision protocols prioritizing speed at the cost of delivering higher doses of radiation should be used in more severe patients. In unstable patients who cannot be examined by CT, X-rays of the chest and pelvis and FAST or e-FAST ultrasound studies, although less sensitive than CT, enable the detection of situations that require immediate treatment. This article reviews the imaging techniques and CT protocols for the initial hospital workup for patients with multiple trauma.

Deep learning for emergency ascites diagnosis using ultrasonography images

PURPOSE

The detection of abdominal free fluid or hemoperitoneum can provide critical information for clinical diagnosis and treatment, particularly in emergencies. This study investigates the use of deep learning (DL) for identifying peritoneal free fluid in ultrasonography (US) images of the abdominal cavity, which can help inexperienced physicians or non-professional people in diagnosis. It focuses specifically on first-response scenarios involving focused assessment with sonography for trauma (FAST) technique.

METHODS

A total of 2985 US images were collected from ascites patients treated from 1 January 2016 to 31 December 2017 at the Shenzhen Second People's Hospital. The data were categorized as Ascites-1, Ascites-2, or Ascites-3, based on the surrounding anatomy. A uniform standard for regions of interest (ROIs) and the lack of obstruction from acoustic shadow was used to classify positive samples. These images were then divided into training (90%) and test (10%) datasets to evaluate the performance of a U-net model, utilizing an encoder-decoder architecture and contracting and expansive paths, developed as part of the study.

RESULTS

Test results produced sensitivity and specificity values of 94.38% and 68.13%, respectively, in the diagnosis of Ascites-1 US images, with an average Dice coefficient of 0.65 (standard deviation [SD] = 0.21). Similarly, the sensitivity and specificity for Ascites-2 were 97.12% and 86.33%, respectively, with an average Dice coefficient of 0.79 (SD = 0.14). The accuracy and area under the curve (AUC) were 81.25% and 0.76 for Ascites-1 and 91.73% and 0.91 for Ascites-2.

CONCLUSION

The results produced by the U-net demonstrate the viability of DL for automated ascites diagnosis. This suggests the proposed technique could be highly valuable for improving FAST-based preliminary diagnoses, particularly in emergency scenarios.

The Technique and Advantages of Contrast-Enhanced Ultrasound in the Diagnosis and Follow-Up of Traumatic Abdomen Solid Organ Injuries

Trauma is one of the most common causes of death or permanent disability in young people, so a timely diagnostic approach is crucial. In polytrauma patients, CEUS (contrast enhanced ultrasound) has been shown to be more sensitive than US (ultrasound) for the detection of solid organ injuries, improving the identification and grading of traumatic abdominal lesions with levels of sensitivity and specificity similar to those seen with MDCT (multidetector tomography). CEUS is recommended for the diagnostic evaluation of hemodynamically stable patients with isolated blunt moderate-energy abdominal traumas and the diagnostic follow-up of conservatively managed abdominal traumas. In this pictorial review, we illustrate the advantages and disadvantages of CEUS and the procedure details with tips and tricks during the investigation of blunt moderate-energy abdominal trauma as well as during follow-up in non-operative management.

Highlights of the development in ultrasound during the last 70 years: A historical review

This review looks at highlights of the development in ultrasound, ranging from interventional ultrasound and Doppler to the newest techniques like contrast-enhanced ultrasound and elastography, and gives reference to some of the valuable articles in Acta Radiologica. Ultrasound equipment is now available in any size and for any purpose, ranging from handheld devices to high-end devices, and the scientific societies include ultrasound professionals of all disciplines publishing guidelines and recommendations. Interventional ultrasound is expanding the field of use of ultrasound-guided interventions into nearly all specialties of medicine, from ultrasound guidance in minimally invasive robotic procedures to simple ultrasound-guided punctures performed by general practitioners. Each medical specialty is urged to define minimum requirements for equipment, education, training, and maintenance of skills, also for medical students. The clinical application of contrast-enhanced ultrasound and elastography is a topic often seen in current research settings.

Contrast-enhanced US for the Interventional Radiologist: Current and Emerging Applications

US is a powerful and nearly ubiquitous tool in the practice of interventional radiology. Use of contrast-enhanced US (CEUS) has gained traction in diagnostic imaging given the recent approval by the U.S. Food and Drug Administration (FDA) of microbubble contrast agents for use in the liver, such as sulfur hexafluoride lipid-type A microspheres. Adoption of CEUS by interventional radiologists can enhance not only procedure guidance but also preprocedure patient evaluation and assessment of treatment response across a wide spectrum of oncologic, vascular, and nonvascular procedures. In addition, the unique physical properties of microbubble contrast agents make them amenable as therapeutic vehicles in themselves, which can lay a foundation for future therapeutic innovations in the field in drug delivery, thrombolysis, and vascular flow augmentation. The purpose of this article is to provide an introduction to and overview of CEUS aimed at the interventional radiologist, highlighting its role before, during, and after frequently practiced oncologic and vascular interventions such as biopsy, ablation, transarterial chemoembolization, detection and control of hemorrhage, evaluation of transjugular intrahepatic portosystemic shunts (TIPS), detection of aortic endograft endoleak, thrombus detection and evaluation, evaluation of vascular malformations, lymphangiography, and percutaneous drain placement. Basic physical principles of CEUS, injection and scanning protocols, and logistics for practice implementation are also discussed. Early adoption of CEUS by the interventional radiology community will ensure rapid innovation of the field and development of future novel procedures. Online supplemental material is available for this article. ^©RSNA, 2020.

Contrast-Enhanced Ultrasound (CEUS) in Non-Traumatic Abdominal Emergencies

Conventional ultrasound imaging (US) is the first-line investigation in acute non-traumatic abdominal emergencies, but sometimes it needs further examinations, such as computed tomography (CT), to reach a certain diagnosis. Contrast-enhanced ultrasound (CEUS), through injection of contrast medium, may provide the radiologist with additional information that could not be investigated with baseline US. It could help reach a diagnosis and rapidly determine the proper therapy in an emergency setting. The purpose of this review is to explain and illustrate the various possibilities and limitations of CEUS in acute non-traumatic abdominal diseases, in particular acute inflammation, parenchymal infarcts, and hemorrhages.

Diagnostic options for blunt abdominal trauma

PURPOSE

Physical examination, laboratory tests, ultrasound, conventional radiography, multislice computed tomography (MSCT), and diagnostic laparoscopy are used for diagnosing blunt abdominal trauma. In this article, we investigate and evaluate the usefulness and limitations of various diagnostic modalities on the basis of a comprehensive review of the literature.

METHODS

We searched commonly used databases in order to obtain information about the aforementioned diagnostic modalities. Relevant articles were included in the literature review. On the basis of the results of our comprehensive analysis of the literature and a current case, we offer a diagnostic algorithm.

RESULTS

A total of 86 studies were included in the review. Ecchymosis of the abdominal wall (seat belt sign) is a clinical sign that has a high predictive value. Laboratory values such as those for haematocrit, haemoglobin, base excess or deficit, and international normalised ratio (INR) are prognostic parameters that are useful in guiding therapy. Extended focused assessment with sonography for trauma (eFAST) has become a well established component of the trauma room algorithm but is of limited usefulness in the diagnosis of blunt abdominal trauma. Compared with all other diagnostic modalities, MSCT has the highest sensitivity and specificity. Diagnostic laparoscopy is an invasive technique that may also serve as a therapeutic tool and is particularly suited for haemodynamically stable patients with suspected hollow viscus injuries.

CONCLUSIONS

MSCT is the gold standard diagnostic modality for blunt abdominal trauma because of its high sensitivity and specificity in detecting relevant intra-abdominal injuries. In many cases, however, clinical, laboratory and imaging findings must be interpreted jointly for an adequate evaluation of a patient's injuries and for treatment planning since these data supplement and complement one another. Patients with blunt abdominal trauma should be admitted for clinical observation over a minimum period of 24 h since there is no investigation that can reliably rule out intra-abdominal injuries.

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.

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.

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.

Emergency and critical care applications for contrast-enhanced ultrasound

INTRODUCTION

Contrast-enhanced ultrasound (CEUS) using intravascular microbubbles has potential to revolutionize point-of-care ultrasonography by expanding the use of ultrasonography into clinical scenarios previously reserved for computed tomography (CT), magnetic resonance imaging, or angiography.

METHODS

We performed a literature search and report clinical experience to provide an introduction to CEUS and describe its current applications for point-of-care indications.

RESULTS

The uses of CEUS include several applications highly relevant for emergency medicine, such as solid-organ injuries, actively bleeding hematomas, or abdominal aortic aneurysms. Compared with CT as the preeminent advanced imaging modality in the emergency department, CEUS is low cost, radiation sparing, repeatable, and readily available. It does not require sedation, preprocedural laboratory assessment, or transportation to the radiology suite.

CONCLUSIONS

CEUS is a promising imaging technique for point-of-care applications in pediatric and adult patients and can be applied for patients with allergy to CT contrast medium or with impaired renal function. More high-quality CEUS research focusing on accuracy, patient safety, health care costs, and throughput times is needed to validate its use in emergency and critical care settings.

MRI of popliteo-meniscal fasciculi of the knee: a pictorial review

The popliteomeniscal fascicules (PMFs) provide the attachment of the lateral meniscus to the popliteus musculotendinous region, forming the floor and the roof the popliteal hiatus. In the second half of 1900's, some anatomic studies claim the important function of the PMF as stabilizers of the lateral meniscus; these anatomical structures work in conjunction with the popliteus musculotendinous unit to prevent excessive lateral meniscal movement and possible meniscus subluxation. A correct diagnosis of the PMFs pathology is crucial to establish the suitable surgical treatment for each patient. MRI is a well-established imaging technique in the musculoskeletal system and the frequency of recognition of normal PMF in the normal knees is high in almost all MRI studies. At day, the gold standard for diagnosis is the arthroscopic evaluation that allows the direct visualization of the popliteo-meniscal ligaments at popliteal hiatus and evaluation of lateral meniscal movements. For this reason if unstable condition of meniscus was suspected, arthroscopic observation with probing into the popliteo-meniscal fascicle area is essential for the identification of the fascicle tears. Despite many treatments have being proposed in literature since now there is high recurrence of knee locking after repair and it is fundamental to develop new surgical techniques in order to achieve better outcome.

Dynamic MRI in the evaluation of the spine: state of the art

INTRODUCTION

Degenerative disease of the spine is a generic term encompassing a wide range of different disease processes, which leads to spinal instability; traumatic/neoplastic events can accelerate this aging process. Therefore, the dynamic nature of the spine and its mobility across multiple segments is difficult to depict with any single imaging modality.

METHODS

A review of PubMed databases for articles published about kMRI in patients with cervical and lumbar spinal desease was performed. We focused on the physiopathological changes in the transition from supine to upright position in spine instability.

DISCUSSION

Until a few years ago, X-ray was the only imaging modality for the spine in the upright position. Of the imaging techniques currently available, MRI provides the greatest range of information and the most accurate delineation of soft-tissue and osseous structures. Conventional MRI examinations of the spine usually are performed in supine position, in functional rest, but the lumbar spine instability is often shown only by upright standing. This can result in negative findings, even in the presence of symptoms. Regardless, the final result is distorted. To overcome this limitation, Kinetic MRI (kMRI) can image patients in a weight-bearing position and in flexed and extended positions, thus revealing abnormalities that are missed by traditional MRI studies.

CONCLUSION

Despite some limitations, the upright MRI can be a complementary investigation to the traditional methods when there are negative results in conventional MRI in symptomatic patients or when surgical therapy is scheduled.

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.

Pediatric musculoskeletal injuries: role of ultrasound and magnetic resonance imaging

Pediatric musculoskeletal system is particularly prone to traumatic and sports-related injuries, both acute and chronic, i.e., overuse injuries, because of inherent conditions of weakness, such as the open physis, representing the weakest aspect within the bone, the ligamentous supports and changing biomechanics. Being aware that a quick diagnosis is essential to preserve the good functionality of the limb involved, it is mandatory for the radiologist to recognize the most common patterns of these injuries, identifying those requiring a prompt surgery, as well as be confident with the technique performed, and be supported by an important background experience and knowledge skills.

Enhancing the role of paediatric ultrasound with microbubbles: a review of intravenous applications

Contrast-enhanced ultrasound (CEUS) represents a complementary technique to greyscale and colour Doppler ultrasonography which allows for real-time visualization and characterization of tissue perfusion. Its inherent advantages in the child makes ultrasonography an ideal imaging modality; repeatability and good tolerance along with the avoidance of CT, a source of ionizing radiation, renders ultrasonography imaging desirable. Although currently paediatric CEUS is principally used in an "off-label" manner, ultrasonography contrast agents have received regulatory approval for assessment of paediatric focal liver lesions (FLL) in the USA. The safety of ultrasound contrast-agents is well documented in adults, as safe as or even surpassing the safety profile of CT and MR contrast agents. Except for the established intracavitary use of CEUS in voiding urosonography, i.v. paediatric applications have been introduced with promising results in the abdominal trauma initial diagnosis and follow-up, characterization and differential diagnosis of FLL and characterization of lung, pleura, renal and splenic pathology. CEUS has also been used to detect complications after paediatric transplantation, evaluate inflammatory bowel disease activity and assess tumour response to antiangiogenic therapy. The purpose of this review was to present these novel i.v. paediatric applications of CEUS and discuss their value.

Pediatric blunt abdominal trauma: current management

PURPOSE OF REVIEW

Nonoperative management of pediatric blunt abdominal injury has changed significantly in the last few years.

RECENT FINDINGS

Improved resource utilization in the diagnosis of pediatric abdominal injury has been described. Hemodynamic status, rather than grade of injury, now guides care. Stable patients spend less time in the hospital, return to school upon discharge, and are allowed lower hemoglobin levels prior to transfusion. ICUs are reserved for those with recent or ongoing bleeding, previously unstable patients, or children with concomitant injuries necessitating ICU. Risk factors for failure and evidence for adjuncts to nonoperative management are emerging. Operative management of certain pancreatic injuries may have more favorable outcomes than nonoperative management.

SUMMARY

Sufficient evidence has become available to radically change the management of pediatric abdominal injury, which is being incorporated into new evidence-based management algorithms.

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.

Contrast-enhanced ultrasound (CEUS) in blunt abdominal trauma

Baseline ultrasound is essential in the early assessment of patients with a huge haemoperitoneum undergoing an immediate abdominal surgery; nevertheless, even with a highly experienced operator, it is not sufficient to exclude parenchymal injuries. More recently, a new ultrasound technique using second generation contrast agents, named contrast-enhanced ultrasound (CEUS) has been developed. This technique allows all the vascular phase to be performed in real time, increasing ultrasound capability to detect parenchymal injuries, enhancing some qualitative findings, such as lesion extension, margins and its relationship with capsule and vessels. CEUS has been demonstrated to be almost as sensitive as contrast-enhanced CT in the detection of traumatic injuries in patients with low-energy isolated abdominal trauma, with levels of sensitivity and specificity up to 95%. Several studies demonstrated its ability to detect lesions occurring in the liver, spleen, pancreas and kidneys and also to recognize active bleeding as hyperechoic bands appearing as round or oval spots of variable size. Its role seems to be really relevant in paediatric patients, thus avoiding a routine exposure to ionizing radiation. Nevertheless, CEUS is strongly operator dependent, and it has some limitations, such as the cost of contrast media, lack of panoramicity, the difficulty to explore some deep regions and the poor ability to detect injuries to the urinary tract. On the other hand, it is timesaving, and it has several advantages, such as its portability, the safety of contrast agent, the lack to ionizing radiation exposure and therefore its repeatability, which allows follow-up of those traumas managed conservatively, especially in cases of fertile females and paediatric patients.

International guidelines for contrast-enhanced ultrasonography: ultrasound imaging in the new millennium

The intent of this review is to discuss and comment on common clinical scenarios in which contrast-enhanced ultrasonography (CEUS) may play a decisive role and to illustrate important points with typical cases. With the advent of CEUS, the scope of indications for ultrasonography has been dramatically extended, and now includes functional imaging and tissue characterization, which in many cases enable tumor diagnosis without a biopsy. It is virtually impossible to imagine the practice of modern medicine as we know it in high-income countries without the use of imaging, and yet, an estimated two thirds of the global population may receive no such care. Ultrasound imaging with CEUS has the potential to correct this inequity.

Comparison between MRI and CEUS in the follow-up of patients with blunt abdominal trauma managed conservatively

INTRODUCTION

Over the past two decades, there has been a shift toward non-operative treatment of patients undergoing a solid organ injury, thus requiring an increasing number of imaging studies to monitor the healing of lesions, which were performed by computed tomography (CT). In consideration of the use of ionizing radiation and contrast media, nowadays there is a trend toward the use contrast-enhanced ultrasound (CEUS) in the follow-up of blunt abdominal trauma. However CEUS has some limits, especially in the assessments of small lesions and in the evaluation of urinary tract lesions and vascular complications. Magnetic resonance imaging (MRI) is a useful alternative, since its lack of use of ionizing radiation, its panoramicity, the possibility to avoid contrast media and the ability to properly evaluate even small lesions. The aim of this study is to evaluate the usefulness and the feasibility of MRI in the follow-up of patients with low-grade blunt abdominal trauma.

MATERIALS AND METHODS

We performed a retrospective review of a cohort including 270 consecutive patients with a history of blunt abdominal trauma; among them, 118 underwent a high-energy trauma, and 152 a low-energy trauma. 124 patients had findings of abdominal injuries at the contrast-enhanced multidetector CT (CE-MDCT), including 68 from the group of major trauma and 56 from the group of minor trauma. 39 patients were operated for incoming lesions. The remaining 85 patients were treated conservatively. Eight patients underwent surgery later for delayed bleeding. The remaining 77 underwent the full follow-up protocol. Follow-up protocol included CEUS at 24 and 72 h and CEUS and MRI at 1 month after trauma; only MRI was performed until the complete resolution.

RESULTS

CEUS at 24-h and at 72-h from trauma showed a very good correlation with onset CE-MDCT in lesions staging. With respect to onset CE-MDCT, CEUS did not identified 2 adrenal injuries and 2 lesions of urinary tract, an intrinsic limit of this technique. CEUS performed at 1 month did not show traumatic lesions in 49/77 of patients. In the remaining 28/77 cases, CEUS demonstrated reduction of the size of the lesions ranging from 25 to 50%. MRI performed at 1 month from trauma did not show traumatic injuries in 37/77 patients; it demonstrated persistence of organ lesion in 40/77 patients. Therefore, in 12/77 patients MRI performed at 1-month demonstrated the persistence of minimal or moderate organ injury, while CEUS was completely negative. In addition, MRI allowed to enhance the persistence of adrenal lesions in 2 cases and the integrity of urinary tract in 2. In the remaining 28 patients, in which both CEUS and MRI showed disease persistence, MRI, however, allowed a better definition of injury extension with respect to CEUS, in terms of dimensions, edges, and morphological evolution.

DISCUSSION AND CONCLUSIONS

MRI allowed to make a better assessment of injuries than CEUS, allowing also a temporal stage of lesions. Infact, there are different evolution stages corresponding to accurate imaging findings. To our knowledge, this is the first study that describes the evolution of blood collection in parenchymal abdominal organs. Therefore, in patients who underwent abdominal traumatic injuries conservatively treated, the follow-up at 1 month can be made by MRI, due to its panoramicity and its high contrast resolution, which allow a better morphological and temporal trauma staging respect to the CEUS.

Accuracy of contrast-enhanced ultrasound (CEUS) in the identification and characterization of traumatic solid organ lesions in children: a retrospective comparison with baseline US and CE-MDCT

INTRODUCTION

Localized low-energy abdominal trauma is very frequent in the pediatric population. The findings of several studies have shown that ultrasonography (US) can represent a useful and cost-effective tool in the evaluation of blunt abdominal trauma both in adults and children. However, many parenchymal injuries are not correctly visualized at baseline US examination. The introduction of specific US contrast agents contrast-enhanced ultrasound (CEUS) has enabled a better identification of traumatic organ injuries. The correct use of CEUS could therefore identify and select the children who need further diagnostic investigation computed tomography (CT), avoiding unnecessary radiation and iodinated contrast medium exposure. The purpose of our study was to assess the sensibility and feasibility of CEUS in the assessment of low-energy abdominal trauma compared to baseline US in pediatric patients, using contrast-enhanced MDCT as the reference standard.

MATERIALS AND METHODS

We retrospectively reviewed 73 children (51 M and 22 F; mean age 8.7 ± 2.8 years) who presented in our Emergency Department between October 2012 and October 2013, with history of minor abdominal trauma according to the Abbreviated Injury Scale and who underwent US, CEUS, and CE-MDCT. Inclusion criteria were: male or female, aged 0-16, hemodynamically stable patients with a history of minor blunt abdominal trauma. Exclusion criteria were adulthood, hemodynamical instability, history of major trauma. Sensitivity, specificity, PPV, NPV, and accuracy were determined for US and CEUS compared to MDCT.

RESULTS

6/73 patients were negative at US, CEUS, and MDCT for the presence of organ injuries. In the remaining 67 patients, US depicted 26/67 parenchymal lesions. CEUS identified 67/67 patients (67/67) with parenchymal lesions: 21 lesions of the liver (28.8 %), 26 lesions of the spleen (35.6 %), 7 lesions of right kidney (9.6 %), 13 lesions of left kidney. MDCT confirmed all parenchymal lesions (67/67). Thus, the diagnostic performance of CEUS was better than that of US, as sensitivity, specificity, PPV, NPV, and accuracy were 100, 100, 100, 100, and 100 % for CEUS and 38.8, 100, 100, 12.8, and 44 % for US. In some patients CEUS identified also prognostic factors as parenchymal active bleeding in 8 cases, partial devascularization in 1 case; no cases of vascular bleeding, no cases of urinoma. MDCT confirmed all parenchymal lesions. Parenchymal active bleeding was identified in 16 cases, vascular bleeding in 2 cases, urinoma in 2 cases, partial devascularization in 1 case.

CONCLUSIONS

CEUS is more sensitive and accurate than baseline US and almost as sensitive as CT in the identification and characterization of solid organs lesions in blunt abdominal trauma. CT is more sensitive and accurate than CEUS in identifying prognostic indicators, as active bleeding and urinoma. CEUS should be considered as a useful tool in the assessment and monitoring of blunt abdominal trauma in children.

The role of CEUS in the assessment of haemodynamically stable patients with blunt abdominal trauma

Computed tomography (CT) still represents the preferred imaging method in the assessment of patients presenting with multiple trauma. Nevertheless, in patients with low-energy abdominal trauma, the use of CT is debated because of the possible unnecessary radiation exposure. Accordingly, conventional ultrasound (US) imaging has been increasingly employed as the initial imaging modality in the workup of minor traumatic emergency conditions. Focused assessment with sonography for trauma is widely used to detect free intra-abdominal fluid, but its role is controversial, because the absence of free fluid does not exclude the presence of injuries to abdominal organ. Injection of an ultrasound contrast agent (UCA) may give the radiologist relevant additional information to that obtained with conventional US. Thus, in trauma patients, following early assessment with conventional US imaging, a contrast-enhanced US (CEUS) can provide a more reliable evaluation of solid organ injuries and related vascular complications, including active bleeding, pseudoaneurysms, and artero-venous fistulas. CEUS cannot replace abdominal CT, but it represents a noninvasive and repeatable imaging tool capable of providing a reliable assessment of trauma severity and expedite the patient's treatment.

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.