Ultrasound Imaging for Traumatic Brain Injury

Transcranial Doppler Ultrasonography detection on cerebral infarction and blood vessels to evaluate hypoxic ischemic encephalopathy modeling

BACKGROUND

This study aimed to observe changes of rats' brain infarction and blood vessels during neonatal hypoxic ischemic encephalopathy (NHIE) modeling by Transcranial Doppler Ultrasonography (TCD) so as to assess the feasibility of TCD in evaluating NHIE modeling.

METHODS

Postnatal 7-days (d)-old Sprague Dawley (SD) rats were divided into the Sham group, hypoxic-ischemic (HI) group, and hypoxia (H) group. Rats in the HI group and H group were subjected to hypoxia-1 hour (h), 1.5 h and 2.5 h, respectively. Evaluation on brain lesion was made based on Zea-Longa scores, hematoxylin-eosin (HE) staining and Nissl staining. The brain infarction and blood vessels of rats were monitored and analyzed under TCD. Correlation analysis was applied to reveal the connection between hypoxic duration and infarct size detected by TCD or Nissl staining.

RESULTS

In H and HI modeling, longer duration of hypoxia was associated with higher Zea-Longa scores and more severe nerve damage. On the 1 d after modeling, necrosis was found in SD rats' brain indicated by HE and Nissl staining, which was aggravated as hypoxic duration prolonged. Alteration of brain structures and blood vessels of SD rats was displayed in Sham, HI and H rats under TCD. TCD images for coronal section revealed that brain infarct was detected at the cortex and there was marked cerebrovascular back-flow of HI rats regardless of hypoxic duration. On the 7 d after modeling, similar infarct was detected under TCD at the cortex of HI rats in hypoxia-1 h, 1.5 h and 2.5 h groups, whereas the morphological changes were deteriorated with longer hypoxic time. Correlation analysis revealed positive correlation of hypoxic duration with infarct size detected by histological detection and TCD.

CONCLUSIONS

TCD dynamically monitored cerebral infarction after NHIE modeling, which will be potentially served as a useful auxiliary method for future animal experimental modeling evaluation in the case of less animal sacrifice.

Point-of-Care Ultrasound-History, Current and Evolving Clinical Concepts in Emergency Medicine

Point-of-care ultrasound (PoCUS) has become an indispensable standard in emergency medicine. Emergency medicine ultrasound (EMUS) is the application of bedside PoCUS by the attending emergency physician to assist in the diagnosis and management of many time-sensitive health emergencies. In many ways, using PoCUS is not only the mere application of technology, but also a fusion of already existing examiner skills and technology in the context of a patient encounter. EMUS practice can be defined using distinct anatomy-based applications. The type of applications and their complexity usually depend on local needs and resources, and practice patterns can vary significantly among regions, countries, or even continents. A different approach suggests defining EMUS in categories such as resuscitative, diagnostic, procedural guidance, symptom- or sign-based, and therapeutic. Because EMUS is practiced in a constantly evolving emergency medical setting where no two patient encounters are identical, the concept of EMUS should also be practiced in a fluid, constantly adapting manner driven by the physician treating the patient. Many recent advances in ultrasound technology have received little or no attention from the EMUS community, and several important technical advances and research findings have not been translated into routine clinical practice. The authors believe that four main areas have great potential for the future growth and development of EMUS and are worth integrating: 1. In recent years, many articles have been published on novel ultrasound applications. Only a small percentage has found its way into routine use. We will discuss two important examples: trauma ultrasound that goes beyond e-FAST and EMUS lung ultrasound for suspected pulmonary embolism. 2. The more ultrasound equipment becomes financially affordable; the more ultrasound should be incorporated into the physical examination. This merging and possibly even replacement of aspects of the classical physical exam by technology will likely outperform the isolated use of stethoscope, percussion, and auscultation. 3. The knowledge of pathophysiological processes in acute illness and ultrasound findings should be merged in clinical practice. The translation of this knowledge into practical concepts will allow us to better manage many presentations, such as hypotension or the dyspnea of unclear etiology. 4. Technical innovations such as elastography; CEUS; highly sensitive color Doppler such as M-flow, vector flow, or other novel technology; artificial intelligence; cloud-based POCUS functions; and augmented reality devices such as smart glasses should become standard in emergencies over time.

Intraoperative ultrasound is valuable for detecting intracranial hematoma progression and decreasing mortality in traumatic brain injury

BACKGROUND

Our aim was to explore the clinical benefit of intraoperative ultrasound in decompressive craniectomy (DC) for traumatic brain injury (TBI).

METHODS

From January 1, 2018, through April 30, 2021, 54 patients who developed acute subdural hematoma (SDH) due to blunt injury and underwent DC with or without intraoperative ultrasound assistance were retrospectively included in our study. Logistic regression analyses were performed to compare the therapeutic efficacy in the two groups.

RESULTS

In the ultrasound group (14 patients, 25.93%), intraoperative ultrasound was used for assisting hematoma removal and/or ventriculostomy during DC. In the control group (40 patients, 74.07%), ultrasound was not used during the operation and ventriculostomy was not performed. No statistically significant differences in age, sex, initial Glasgow Coma Scale (GCS) score, blood loss, postoperative intracranial pressure (ICP), duration of hyperosmolar therapy, or Glasgow Outcome Scale Extended (GOS-E) score 6 months after injury were observed. No mortality was recorded in the ultrasound group. The mortality rate in the control group during hospitalization was 25% (p < 0.05).

CONCLUSIONS

Intraoperative ultrasound is helpful for intracranial hematoma removal and ventriculostomy with cerebrospinal fluid drainage and decreases mortality in experienced hands. The reason for higher mortality rate in the control group might result from poor hematoma clearance rate and poor postoperative intracranial pressure control. It is a useful tool for diagnosing and assisting with treatment in cases of TBI.

Variability in the management of infants under 3 months with minor head injury in paediatric emergency departments

INTRODUCTION

In the assessment of infants younger than 3 months with minor traumatic head injury (MHI), it is essential to adapt the indication of imaging tests. The Pediatric Head Injury/Trauma Algorithm (PECARN) clinical prediction rule is the most widely used to guide clinical decision making.

OBJECTIVES

To analyse the variability in the performance of imaging tests in infants under 3 months with MHI in paediatric emergency departments (PEDs) and the adherence of each hospital to the recommendations of the PECARN rule.

POPULATION AND METHODS

We conducted a prospective multicentre observational study in 13 paediatric emergency departments in Spain between May 2017 and November 2020.

RESULTS

Of 21 981 children with MHI, 366 (1.7%) were aged less than 3 months; 195 (53.3%) underwent neuroimaging, with performance of CT scans in 37 (10.1%; interhospital range, 0%-40.0%), skull X-rays in 162 (44.3 %; range, 0%-100%) and transfontanellar ultrasound scans in 22 (6.0%; range, 0%-24.0%). The established recommendations were followed in 25.6% (10/39) of infants classified as high-risk based on PECARN criteria (range, 0%-100%); 37.1% (36/97) classified as intermediate-risk (range, 0%-100%) and 57.4% (132/230) classified as low-risk (range, 0%-100%).

CONCLUSION

We found substantial variability and low adherence to the PECARN recommendations in the performance of imaging tests in infants aged less than 3 months with MHI in Spanish PEDs, mainly due to an excessive use of skull X-rays.

Contrast-Enhanced Ultrasound of Brain Perfusion in Cardiopulmonary Resuscitation

ABSTRACT

To evaluate the feasibility and potential utility of contrast-enhanced ultrasound for real-time imaging of whole-brain perfusion during cardiopulmonary resuscitation (CPR), cardiac arrest was induced in 8- to 7-week-old 10-kg piglets ( Sus scrofa domesticus ). Contrast-enhanced ultrasound was performed through a parietal cranial window in the coronal plane visualizing the thalami during hemodynamic-directed CPR. Whole-brain mean and maximum pixel intensities in each slice during resuscitation were calculated. Piglets were monitored for 24 hours postarrest. Seven piglets achieved return of spontaneous circulation and 6 survived to 24 hours. Of the 6 surviving piglets, 2 piglets demonstrated greater intra-CPR brain enhancement at maximum 73.2% and 42.1% and mean 36.7% and 31.9% enhancement above background, respectively, compared with maximum 5.8%, 22.9%, 6.0%, and 26.6% and mean 5.1%, 8.9%, 2.9%, and 6.6% above background, respectively, in the other 4. Intra-CPR average mean arterial pressures were similar between all 6 surviving piglets. One piglet achieved return of spontaneous circulation but expired 10 minutes later with enhancement maximum 45.2% and mean 18.9% enhancement above background. The final piglet did not achieve return of spontaneous circulation and exhibited minimal enhancement at maximum 2.8% and mean 0.9% enhancement above background. Contrast-enhanced ultrasound can detect brain perfusion during CPR, identifying a spectrum of cerebral blood flow responses in the brain despite similar systemic hemodynamics. This novel application can form the basis for future large animal model studies and eventually human clinical studies to further explore the neurologic implications of cerebral blood flow responses during resuscitation and stimulate novel strategies for optimizing brain perfusion restoration.

Inhalational Gases for Neuroprotection in Traumatic Brain Injury

Despite multiple prior pharmacological trials in traumatic brain injury (TBI), the search for an effective, safe, and practical treatment of these patients remains ongoing. Given the ease of delivery and rapid absorption into the systemic circulation, inhalational gases that have neuroprotective properties will be an invaluable resource in the clinical management of TBI patients. In this review, we perform a systematic review of both pre-clinical and clinical reports describing inhalational gas therapy in the setting of TBI. Hyperbaric oxygen, which has been investigated for many years, and some of the newest developments are reviewed. Also, promising new therapies such as hydrogen gas, hydrogen sulfide gas, and nitric oxide are discussed. Moreover, novel therapies such as xenon and argon gases and delivery methods using microbubbles are explored.

Risk of Traumatic Brain Injuries in Infants Younger than 3 Months With Minor Blunt Head Trauma

STUDY OBJECTIVE

Infants with head trauma often have subtle findings suggestive of traumatic brain injury. Prediction rules for traumatic brain injury among children with minor head trauma have not been specifically evaluated in infants younger than 3 months old. We aimed to determine the risk of clinically important traumatic brain injuries, traumatic brain injuries on computed tomography (CT) images, and skull fractures in infants younger than 3 months of age who did and did not meet the age-specific Pediatric Emergency Care Applied Research Network (PECARN) low-risk criteria for children with minor blunt head trauma.

METHODS

We conducted a secondary analysis of infants <3 months old in the public use data set from PECARN's prospective observational study of children with minor blunt head trauma. Main outcomes included (1) clinically important traumatic brain injury, (2) traumatic brain injury on CT, and (3) skull fracture on CT.

RESULTS

Of 10,904 patients <2 years old, 1,081 (9.9%) with complete data were <3 months old; most (750/1081, 69.6%) sustained falls, and 633/1081 (58.6%) underwent CT scans. Of the 514/1081 (47.5%) infants who met the PECARN low-risk criteria, 1/514 (0.2%, 95% confidence interval [CI] 0.005% to 1.1%), 10/197 (5.1%, 2.5% to 9.1%), and 9/197 (4.6%, 2.1% to 8.5%) had clinically important traumatic brain injuries, traumatic brain injuries on CT, and skull fractures, respectively. Of 567 infants who did not meet the low-risk PECARN criteria, 24/567 (4.2%, 95% CI 2.7% to 6.2%), 94/436 (21.3%, 95% CI 17.6% to 25.5%), and 122/436 (28.0%, 95% CI 23.8% to 32.5%) had clinically important traumatic brain injuries, traumatic brain injuries, and skull fractures, respectively.

CONCLUSION

The PECARN traumatic brain injury low-risk criteria accurately identified infants <3 months old at low risk of clinically important traumatic brain injuries. However, infants at low risk for clinically important traumatic brain injuries remained at risk for traumatic brain injuries on CT, suggesting the need for a cautious approach in these infants.

Recent Advances in Fluorescence Imaging of Traumatic Brain Injury in Animal Models

Traumatic brain injury (TBI) is one of the top three specific neurological disorders, requiring reliable, rapid, and sensitive imaging of brain vessels, tissues, and cells for effective diagnosis and treatment. Although the use of medical imaging such as computed tomography (CT) and magnetic resonance imaging (MRI) for the TBI detection is well established, the exploration of novel TBI imaging techniques is of great interest. In this review, recent advances in fluorescence imaging for the diagnosis and evaluation of TBI are summarized and discussed in three sections: imaging of cerebral vessels, imaging of brain tissues and cells, and imaging of TBI-related biomarkers. Design strategies for probes and labels used in TBI fluorescence imaging are also described in detail to inspire broader applications. Moreover, the multimodal TBI imaging platforms combining MRI and fluorescence imaging are also briefly introduced. It is hoped that this review will promote more studies on TBI fluorescence imaging, and enable its use for clinical diagnosis as early as possible, helping TBI patients get better treatment and rehabilitation.

Prehospital Detection of Life-Threatening Intracranial Pathology: An Unmet Need for Severe TBI in Austere, Rural, and Remote Areas

Severe traumatic brain injury (TBI) is a leading cause of death and disability worldwide, especially in low- and middle-income countries, and in austere, rural, and remote settings. The purpose of this Perspective is to challenge the notion that accurate and actionable diagnosis of the most severe brain injuries should be limited to physicians and other highly-trained specialists located at hospitals. Further, we aim to demonstrate that the great opportunity to improve severe TBI care is in the prehospital setting. Here, we discuss potential applications of prehospital diagnostics, including ultrasound and near-infrared spectroscopy (NIRS) for detection of life-threatening subdural and epidural hemorrhage, as well as monitoring of cerebral hemodynamics following severe TBI. Ultrasound-based methods for assessment of cerebrovascular hemodynamics, vasospasm, and intracranial pressure have substantial promise, but have been mainly used in hospital settings; substantial development will be required for prehospital optimization. Compared to ultrasound, NIRS is better suited to assess certain aspects of intracranial pathology and has a smaller form factor. Thus, NIRS is potentially closer to becoming a reliable method for non-invasive intracranial assessment and cerebral monitoring in the prehospital setting. While one current continuous wave NIRS-based device has been FDA-approved for detection of subdural and epidural hemorrhage, NIRS methods using frequency domain technology have greater potential to improve diagnosis and monitoring in the prehospital setting. In addition to better technology, advances in large animal models, provider training, and implementation science represent opportunities to accelerate progress in prehospital care for severe TBI in austere, rural, and remote areas.

Neonatal head injuries: A prospective Paediatric Research in Emergency Departments International Collaborative cohort study

AIM

To characterise the causes, clinical characteristics and short-term outcomes of neonates who presented to paediatric emergency departments with a head injury.

METHODS

Secondary analysis of a prospective data set of paediatric head injuries at 10 emergency departments in Australia and New Zealand. Patients without neuroimaging were followed up by telephone call. We extracted epidemiological information, clinical findings and outcomes in neonates (≤28 days).

RESULTS

Of 20 137 children with head injuries, 93 (0.5%) occurred in neonates. These were mostly fall-related (75.2%), commonly from a care giver's arms, or due to being accidentally struck by a person/object (20.4%). There were three cases of non-accidental head injuries (3.2%). Most neonates were asymptomatic (67.7%) and many had no findings on examination (47.3%). Most neonates had a Glasgow Coma Scale 15 (89.2%) or 14 (7.5%). A total of 15.1% presented with vomiting and 5.4% were abnormally drowsy. None had experienced a loss of consciousness. The most common findings on examination were scalp haematoma (28.0%) and possible palpable skull fracture (6.5%); 8.6% underwent computed tomography brain scan and 4.3% received an ultrasound. Five of eight computed tomography scan (5.4% of neonates overall) showed traumatic brain injury and two of four (2.2% overall) had traumatic brain injury on ultrasound. Thirty-seven percent were admitted, one patient was intubated and none had neurosurgery or died.

CONCLUSIONS

Neonatal head injuries are rare with a mostly benign short-term outcome and are appropriate for observation. However, non-accidental injuries need to be considered.

Transcranial Color-Coded Sonography for the Detection of Cerebral Veins and Sinuses and Diagnosis of Cerebral Venous Sinus Thrombosis

This study aimed to determine the detection rate of transcranial color-coded sonography (TCCS) of cerebral veins and sinuses and to explore the diagnostic accuracy of TCCS for straight sinus (SS) and transverse sinus (TS) thromboses. The detection rates of cerebral veins and sinuses using TCCS and contrast-enhanced TCCS (CE-TCCS) were analyzed. The diagnostic accuracy of CE-TCCS was evaluated. Median time from symptoms to CE-TCCS was 10 (range, 1-150) d. The detection rate of bilateral basal veins of Rosenthal was 100% by CE-TCCS, followed by right TS (91.89%), SS (88.12%), left TS (74.59%) and vein of Galen (70.27%). Compared with magnetic resonance imaging/magnetic resonance venography, CE-TCCS showed 100% sensitivity and 96.3% specificity for SS thrombosis, 100% and 100% for right TS thrombosis and 100% and 94.4% for left TS thrombosis. In conclusion, CE-TCCS shows high identification rates of cerebral veins and sinuses and a high diagnostic accuracy for SS and TS thrombosis.