Feasibility of FAST examination performance with ultrasound contrast

Lung ultrasound for detecting pneumothorax in injured children: preliminary experience at a community-based Level II pediatric trauma center

BACKGROUND

Ultrasound (US) has been used in the adult trauma population with reported moderate to high sensitivities, but data are scarce in the pediatric trauma population.

OBJECTIVE

The purpose of this study was to specifically examine the sensitivity and specificity of one lung US methodology (single-point anterior exam) in the pediatric trauma population when compared to chest radiography or CT.

MATERIALS AND METHODS

We conducted a retrospective review of pediatric trauma patients who received lung US as an extension of the focused assessment with sonography for trauma (FAST) exam. We compared lung US findings with chest radiography and CT scans.

RESULTS

Two hundred twenty-six pediatric trauma patients underwent lung US exam with confirmatory exams; 11 pneumothoraces (4.8%) were observed. Of those 11, 6 were evaluated as false negatives on the lung US. Analyses resulted in 45.5% sensitivity, 98.6% specificity and 96.0% accuracy. Pneumothoraces undetected by lung US were small and apical and were likely not observed because of their size and location. None of the false negatives required intervention. All true positives were associated with lung contusions.

CONCLUSION

Pneumothorax is less common in the pediatric than the adult trauma population, and when encountered in children pneumothorax is often occult and might be associated with lung contusions. Existing evidence supports the usefulness of chest US in detecting pneumothorax in adults and suggests that it can be translated to injured children. However, our findings suggest that the sensitivity of lung US as a single-point anterior exam extension of the FAST exam might not be as reliable in the pediatric trauma population as in adults. Other methodologies using lung US might improve sensitivity.

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.

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.

The FAST and E-FAST in 2013: trauma ultrasonography: overview, practical techniques, controversies, and new frontiers

This article reviews important literature on the FAST and E-FAST examinations in adults. It also reviews key pitfalls, limitations, and controversies. A practical "how-to" guide is presented. Lastly, new frontiers are explored.

New and old tools for abdominal imaging in critically ill patients

Diagnostic imaging technology has advanced considerably during the past two decades. Different imaging techniques have been proposed for abdominal imaging in critically ill patients like plain radiography, sonography, computed tomography (CT), magnetic resonance and positron emission tomography. Sonography has been proven to be effective to detect free intra-peritoneal fluid and it is considered one of the primary diagnostic modalities for abdominal evaluation for trauma assessment. In our opinion sonography should replace other invasive techniques to rapidly triage blunt trauma patients with unstable vital signs and examine the peritoneal cavity as a site of major haemorrhage to expedite exploratory laparotomy. On the other hand, CT has become the imaging modality of choice in hemodynamically stable patients with multisystem blunt and penetrating trauma. New developments in the quantitative analysis of the CT images will improve our knowledge of pathophysiology, diagnostic and therapeutic management of abdominal pathologies in critically ill patients.

Imaging of perfusion using ultrasound

Ultrasound can be used to image perfusion in two ways: the traditional one using Doppler and the more recent using microbubble contrast agents. Doppler is simple to use and inexpensive but is limited to larger vessels with faster flow rates. It cannot interrogate the microvasculature because bulk tissue movement is faster than capillary flow. It has been used for liver and tumour flow. Contrast studies are much richer and can assess both the macro- and microcirculation. One approach analyses the time-intensity curves in a region of interest, e.g. a tumour, myocardium, brain, following bolus i.v. injection. Another approach measures the time taken for the microbubbles to cross a vascular bed of interest. These arrival times can be useful for the liver in both diffuse and focal diseases and for the kidney. Features derived from time-intensity curves following bolus i.v. injections of microbubbles form sensitive early indicators of the vascular response of tumours to antivascular drugs. This approach, known as dynamic contrast-enhanced ultrasound (DCE-US), has been accepted as a valid technique for monitoring tumour response by several authorities.

CEUS in abdominal trauma: multi-center study

The objective of this study was to evaluate the concordance of US and contrast-enhanced US (CEUS) with CT in the assessment of solid organ injury following blunt trauma. Patients underwent complete US examination, including free fluid search and solid organ analysis. CEUS followed, using low-mechanical index techniques and SonoVue. CT was performed within 1 h. Among 156 enrolled patients, 91 had one or more abnormalities (n = 107) at CT: 26 renal, 38 liver, 43 spleen. Sensitivity, specificity, and accuracy for renal trauma at baseline US were 36%, 98%, and 88%, respectively, after CEUS values increased to 69%, 99%, and 94%. For liver baseline US values were 68%, 97%, and 90%; after CEUS were 84%, 99%, and 96%. For spleen, results were 77%, 96%, and 91% at baseline US and 93%, 99%, and 97% after CEUS. Per patient evaluation gave the following results in terms of sensitivity, specificity and accuracy: 79%, 82%, 80% at baseline US; 94%, 89%, and 92% following CEUS. CEUS is more sensitive than US in the detection of solid organ injury, potentially reducing the need for further imaging. False negatives from CEUS are due to minor injuries, without relevant consequences for patient management and prognosis.

The value of contrast-enhanced gray-scale ultrasound in the diagnosis of hepatic trauma: an animal experiment

BACKGROUND

Conventional ultrasonography (US) shows markedly lower sensitivity in detecting parenchymal injury and active bleeding in abdominal organs. This study was designed to evaluate the utility of contrast-enhanced US (CEUS) in the diagnosis of blunt trauma and active hemorrhage of the liver in an animal model.

METHODS

Sixteen blunt injuries and 40 lacerations with active hemorrhage were created in livers of 14 pigs using laparotomy. The lacerations were divided into two groups: group I, in which the velocity of the traumatized artery was >20 cm/s; and group II, in which the velocity of the traumatized artery was < or =20 cm/s. Twenty minutes after the blunt trauma and immediately after the laceration was created, conventional US and CEUS were performed to observe the sonographic characteristics of trauma.

RESULTS

The sensitivity of CEUS in detecting blunt hepatic trauma (100%; 16 of 16) was significantly higher than that of conventional US (37.5%; 6 of 16) (p < 0.001) based on the histopathology gold standard. Active hemorrhage was clearly detected as hyperechoic enhanced linear or clumpy regions in all of the lacerations in group I (100%; 20 of 20) and in 65% (13 of 20) of the lacerations in group II on CEUS. Acoustic shadowing was observed posterior to the enhanced hemorrhagic site in 12 lacerations from group I and in five lacerations from group II.

CONCLUSION

In this animal model, CEUS was found to be useful in detecting blunt trauma and active hemorrhage in the liver, which might significantly improve the efficacy of US for the diagnosis of hepatic trauma.

Clinician-performed focused sonography for the resuscitation of trauma

Traumatic death remains pandemic. The majority of preventable deaths occur early and are due to injuries or physiologic derangements in the airway, thoracoabdominal cavities, or brain. Ultrasound is a noninvasive and portable imaging modality that spans a spectrum between the physical examination and diagnostic imaging. It allows trained examiners to immediately confirm important syndromes and answer clinical questions. Newer technologies greatly increase the fidelity, accessibility, ease of use, and informatic manipulation of the results. The early bedside use of focused ultrasound as the initial imaging modality used to detect hemoperitoneum and hemopericardium in the resuscitation of the injured patient has become an accepted standard of care. Widespread dissemination of basic ultrasound skills and technology to facilitate this brings ultrasound to many resuscitative and critical care areas. Although not as widely appreciated, the focused use of ultrasound may also have a role in detecting hemothoraces and pneumothoraces, guiding airway management, and detecting increased intracranial pressure. Intensivists generally utilize a treating philosophy that requires the real-time integration of many divergent sources of information regarding their patients' anatomy and physiology. They are therefore positioned to take advantage of focused resuscitative ultrasound, which offers immediate diagnostic information in the early care of the critically injured.

Detection of bleeding in injured femoral arteries with contrast-enhanced sonography

OBJECTIVE

The purpose of this study was to investigate the feasibility of detecting acute arterial bleeding by means of contrast-enhanced sonography.

METHODS

Puncture injury was produced transcutaneously with an 18-gauge needle in 26 femoral arteries (13 in the control group and 13 in the contrast-enhanced group) of rabbits. A sonographic contrast agent (Optison; Mallinckrodt Inc, St Louis, MO) was administered intravenously at a dose of 0.06 to 0.07 mL/kg. Sonography of the femoral arteries was performed before and after injury, both before and after injection of Optison, with B-mode imaging, color Doppler imaging, and pulse inversion harmonic imaging (PIHI).

RESULTS

The specific location of active bleeding could not be visualized in B-mode and PIHI scans in the control group (no Optison injection). After administration of Optison, the bleeding site was visualized because of the increased echogenicity of the extravasated blood at the puncture site in both B-mode imaging and PIHI. In color Doppler images, bleeding sites were localized successfully in 84.6% of the cases in the presence of Optison and in 30.8% of the cases without Optison. Histologic examination (light microscopy) of the hematoma confirmed the presence of contrast agent microbubbles in the extravascular space surrounding the artery.

CONCLUSIONS

Contrast-enhanced sonography may provide an effective method for detecting arterial bleeding.