Validation of the NeuroImaging Radiological Interpretation System for Acute Traumatic Brain Injury.

PURPOSE: The aim of the study was to refine and validate the NeuroImaging Radiological Interpretation System (NIRIS), which was developed to predict management and clinical outcome based on noncontrast head computerized tomography findings in patients suspected of acute traumatic brain injury (TBI). METHODS: We assessed the performance of the NIRIS score in a prospective, single-center cohort of patients suspected of TBI (n = 648) and compared the performance of NIRIS with that of the Marshall and Rotterdam scoring systems. We also revised components of the NIRIS scoring system using decision tree methodologies implemented on pooled data from the retrospective and prospective studies (N = 1190). RESULTS: The NIRIS performed similarly to the Marshall and Rotterdam scoring systems in predicting mortality and markedly better in terms of predicting more granular elements of disposition and management of TBI patients, such as admission, follow-up imaging, intensive care unit stay, and neurosurgical procedures. The revised NIRIS classification correctly predicted disposition and outcome in 91.2% (331/363) after excluding patients with other major extracranial traumatic injuries or intracranial nontraumatic injuries. CONCLUSIONS: The present study further demonstrates the predictive value of NIRIS in guiding standardized clinical management and decision-making regarding treatment options for TBI patients.

Neuroimaging Radiological Interpretation System for Acute Traumatic Brain Injury.

The purpose of the study was to develop an outcome-based NeuroImaging Radiological Interpretation System (NIRIS) for patients with acute traumatic brain injury (TBI) that would standardize the interpretation of noncontrast head computer tomography (CT) scans and consolidate imaging findings into ordinal severity categories that would inform specific patient management actions and that could be used as a clinical decision support tool. We retrospectively identified all patients transported to our emergency department by ambulance or helicopter for whom a trauma alert was triggered per established criteria and who underwent a noncontrast head CT because of suspicion of TBI, between November 2015 and April 2016. Two neuroradiologists reviewed the noncontrast head CTs and assessed the TBI imaging common data elements (CDEs), as defined by the National Institutes of Health (NIH). Using descriptive statistics and receiver operating characteristic curve analyses to identify imaging characteristics and associated thresholds that best distinguished among outcomes, we classified patients into five mutually exclusive categories: 0-discharge from the emergency department; 1-follow-up brain imaging and/or admission; 2-admission to an advanced care unit; 3-neurosurgical procedure; 4-death up to 6 months after TBI. Sensitivity of NIRIS with respect to each patient's true outcome was then evaluated and compared with that of the Marshall and Rotterdam scoring systems for TBI. In our cohort of 542 patients with TBI, NIRIS was developed to predict discharge (182 patients), follow-up brain imaging/admission (187 patients), need for advanced care unit (151 patients), neurosurgical procedures (10 patients), and death (12 patients). NIRIS performed similarly to the Marshall and Rotterdam scoring systems in terms of predicting death. We developed an interpretation system for neuroimaging using the CDEs that informs specific patient management actions and could be used as a clinical decision support tool for patients with TBI. Our NIRIS classification, with evidence-based grouping of the CDEs into actionable categories, will need to be validated in different TBI populations.

X-linked adrenoleukodystrophy in a chimpanzee due to an ABCD1 mutation reported in multiple unrelated humans.

BACKGROUND: X-linked adrenoleukodystrophy (X-ALD) is a genetic disorder leading to the accumulation of very long chain fatty acids (VLCFA) due to a mutation in the ABCD1 gene. ABCD1 mutations lead to a variety of phenotypes, including cerebral X-ALD and adrenomyeloneuropathy (AMN) in affected males and 80% of carrier females. There is no definite genotype-phenotype correlation with intrafamilial variability. Cerebral X-ALD typically presents in childhood, but can also present in juveniles and adults. The most affected tissues are the white matter of the brain and adrenal cortex. MRI demonstrates a characteristic imaging appearance in cerebral X-ALD that is used as a diagnostic tool. OBJECTIVES: We aim to correlate a mutation in the ABCD1 gene in a chimpanzee to the human disease X-ALD based on MRI features, neurologic symptoms, and plasma levels of VLCFA. METHODS: Diagnosis of X-ALD made using MRI, blood lipid profiling, and DNA sequencing. RESULTS: An 11-year-old chimpanzee showed remarkably similar features to juvenile onset cerebral X-ALD in humans including demyelination of frontal lobes and corpus callosum on MRI, elevated plasma levels of C24:0 and C26:0, and identification of the c.1661G>A ABCD1 variant. CONCLUSIONS: This case study presents the first reported case of a leukodystrophy in a great ape, and underscores the fidelity of MRI pattern recognition in this disorder across species.

Imaging Evaluation of Acute Traumatic Brain Injury.

Traumatic brain injury (TBI) is a major cause of morbidity and mortality worldwide. Imaging plays an important role in the evaluation, diagnosis, and triage of patients with TBI. Recent studies suggest that it also helps predict patient outcomes. TBI consists of multiple pathoanatomic entities. This article reviews the current state of TBI imaging including its indications, benefits and limitations of the modalities, imaging protocols, and imaging findings for each of these pathoanatomic entities. Also briefly surveyed are advanced imaging techniques, which include several promising areas of TBI research.

Orbital and facial fractures.

This article reviews the importance of particular radiologic findings related to facial trauma and their implications for clinical and surgical management. An emphasis is placed on critical imaging signs that warrant immediate surgical attention.

Natural history and prognostic value of corticospinal tract Wallerian degeneration in intracerebral hemorrhage.

BACKGROUND: The purpose of this study was to define the incidence, imaging characteristics, natural history, and prognostic implication of corticospinal tract Wallerian degeneration (CST-WD) in spontaneous intracerebral hemorrhage (ICH) using serial MR imaging. METHODS AND RESULTS: Consecutive ICH patients with supratentorial ICH prospectively underwent serial MRIs at 2, 7, 14, and 21 days. MRIs were analyzed by independent raters for the presence and topographical distribution of CST-WD on diffusion-weighted imaging (DWI). Baseline demographics, hematoma characteristics, ICH score, and admission National Institute of Health Stroke Score (NIHSS) were systematically recorded. Functional outcome at 3 months was assessed by the modified Rankin Scale (mRS) and the motor-NIHSS. Twenty-seven patients underwent 93 MRIs; 88 of these were serially obtained in the first month. In 13 patients (48%), all with deep ICH, CST-WD changes were observed after a median of 7 days (interquartile range, 7 to 8) as reduced diffusion on DWI and progressed rostrocaudally along the CST. CST-WD changes evolved into T2-hyperintense areas after a median of 11 days (interquartile range, 6 to 14) and became atrophic on MRIs obtained after 3 months. In univariate analyses, the presence of CST-WD was associated with poor functional outcome (ie, mRS 4 to 6; P=0.046) and worse motor-NIHSS (5 versus 1, P=0.001) at 3 months. CONCLUSIONS: Wallerian degeneration along the CST is common in spontaneous supratentorial ICH, particularly in deep ICH. It can be detected 1 week after ICH on DWI and progresses rostrocaudally along the CST over time. The presence of CST-WD is associated with poor motor and functional recovery after ICH.

Delayed acute spinal cord injury following intracranial gunshot trauma: case report.

The authors report the case of a patient who presented with a hoarse voice and left hemiparesis following a gunshot injury with trajectory entering the left scapula, traversing the suboccipital bone, and coming to rest in the right lateral medullary cistern. Following recovery from the hemiparesis, abrupt quadriparesis occurred coincident with fall of the bullet into the anterior spinal canal. The bullet was retrieved following a C-2 and C-3 laminectomy, and postoperative MR imaging confirmed signal change in the cord at the level where the bullet had lodged. The patient then made a good neurological recovery. Bullets can fall from the posterior fossa with sufficient momentum to cause an acute spinal cord injury. Consideration for craniotomy and bullet retrieval should be given to large bullets lying in the CSF spaces of the posterior fossa as they pose risk for acute spinal cord injury.

Temporizing treatment of hyperacute subdural hemorrhage by subdural evacuation port system placement.

An acute subdural hematoma (SDH) requiring surgical intervention is treated with craniotomy or craniectomy, in part because it is generally accepted that coagulated blood present in the acute phase cannot be adequately evacuated by less-invasive means such as bur hole drainage. However, a hyperacute SDH in the first few hours after trauma can have mixed-density components on CT scans that are thought to represent subdural blood that is not yet fully coagulated. The authors report a case in which a hyperacute SDH in a patient receiving antiplatelet therapy was treated with the novel technique of temporizing subdural evacuation port system (SEPS) placement. Placement of an SEPS in the intensive care unit allowed for rapid surgical treatment of the patient's elevated intracranial pressure (ICP) by drainage of 70 ml of fresh subdural blood. After initial SEPS-induced stabilization, the patient underwent operative treatment of the SDH by craniotomy. The combined approach of emergency SEPS placement followed by craniotomy resulted in a dramatic recovery, with improvement from coma and extensor posturing to a normal status on neurological evaluation 5 weeks later. In appropriately selected cases, patients with a hyperacute SDH may benefit from SEPS placement to quickly treat elevated ICP, as a bridge to definitive surgical treatment by craniotomy.

Mechanisms of primary blast-induced traumatic brain injury: insights from shock-wave research.

Traumatic brain injury caused by explosive or blast events is traditionally divided into four phases: primary, secondary, tertiary, and quaternary blast injury. These phases of blast-induced traumatic brain injury (bTBI) are biomechanically distinct and can be modeled in both in vivo and in vitro systems. The primary bTBI injury phase represents the response of brain tissue to the initial blast wave. Among the four phases of bTBI, there is a remarkable paucity of information about the cause of primary bTBI. On the other hand, 30 years of research on the medical application of shockwaves (SW) has given us insight into the mechanisms of tissue and cellular damage in bTBI, including both air-mediated and underwater SW sources. From a basic physics perspective, the typical blast wave consists of a lead SW followed by supersonic flow. The resultant tissue injury includes several features observed in bTBI, such as hemorrhage, edema, pseudoaneurysm formation, vasoconstriction, and induction of apoptosis. These are well-described pathological findings within the SW literature. Acoustic impedance mismatch, penetration of tissue by shock/bubble interaction, geometry of the skull, shear stress, tensile stress, and subsequent cavitation formation, are all important factors in determining the extent of SW-induced tissue and cellular injury. Herein we describe the requirements for the adequate experimental set-up when investigating blast-induced tissue and cellular injury; review SW physics, research, and the importance of engineering validation (visualization/pressure measurement/numerical simulation); and, based upon our findings of SW-induced injury, discuss the potential underlying mechanisms of primary bTBI.

Imaging for the diagnosis and management of traumatic brain injury.

To understand the role of imaging in traumatic brain injury (TBI), it is important to appreciate that TBI encompasses a heterogeneous group of intracranial injuries and includes both insults at the time of impact and a deleterious secondary cascade of insults that require optimal medical and surgical management. Initial imaging identifies the acute primary insult that is essential to diagnosing TBI, but serial imaging surveillance is also critical to identifying secondary injuries such as cerebral herniation and swelling that guide neurocritical management. Computed tomography (CT) is the mainstay of TBI imaging in the acute setting, but magnetic resonance tomography (MRI) has better diagnostic sensitivity for nonhemorrhagic contusions and shear-strain injuries. Both CT and MRI can be used to prognosticate clinical outcome, and there is particular interest in advanced applications of both techniques that may greatly improve the sensitivity of conventional CT and MRI for both the diagnosis and prognosis of TBI.

Common data elements in radiologic imaging of traumatic brain injury.

Radiologic brain imaging is the most useful means of visualizing and categorizing the location, nature, and degree of damage to the central nervous system sustained by patients with traumatic brain injury (TBI). In addition to determining acute patient management and prognosis, imaging is crucial for the characterization and classification of injuries for natural history studies and clinical trials. This article is the initial result of a workshop convened by multiple national health care agencies in March 2009 to begin to make recommendations for potential data elements dealing with specific radiologic features and definitions needed to characterize injuries, as well as specific techniques and parameters needed to optimize radiologic data acquisition. The neuroimaging work group included professionals with expertise in basic imaging research and physics, clinical neuroradiology, neurosurgery, neurology, physiatry, psychiatry, TBI research, and research database formation. This article outlines the rationale and overview of their specific recommendations. In addition, we review the contributions of various imaging modalities to the understanding of TBI and the general principles needed for database flexibility and evolution over time to accommodate technical advances.

Head trauma.

Worldwide, an estimated 10 million people are affected annually by traumatic brain injury (TBI). More than 5 million Americans currently live with long-term disability as a result of TBI and more than 1.5 million individuals sustain a new TBI each year. It has been predicted that TBI will become the third leading cause of death and disability in the world by the year 2020. This article outlines the classification of TBI, details the types of lesions encountered, and discusses the various imaging modalities available for the evaluation of TBI.

Common data elements in radiologic imaging of traumatic brain injury.

Traumatic brain injury (TBI) has a poorly understood pathology. Patients suffer from a variety of physical and cognitive effects that worsen as the type of trauma worsens. Some noninvasive insights into the pathophysiology of TBI are possible using magnetic resonance imaging (MRI), computed tomography (CT), and many other forms of imaging as well. A recent workshop was convened to evaluate the common data elements (CDEs) that cut across the imaging field and given the charge to review the contributions of the various imaging modalities to TBI and to prepare an overview of the various clinical manifestations of TBI and their interpretation. Technical details regarding state-of-the-art protocols for both MRI and CT are also presented with the hope of guiding current and future research efforts as to what is possible in the field. Stress was also placed on the potential to create a database of CDEs as a means to best record information from a given patient from the reading of the images.

Benign anterior temporal epidural hematoma: indolent lesion with a characteristic CT imaging appearance after blunt head trauma.

PURPOSE: To study the incidence, pathogenesis, imaging characteristics, and clinical importance of a unique subtype of epidural hematoma (EDH) associated with blunt head trauma. MATERIALS AND METHODS: This study was reviewed and approved by the hospital's Institutional Review Board and was compliant with HIPAA. Informed consent was waived. The investigation was a retrospective study of 200 patients with acute supratentorial EDH, defined as a biconvex, high-attenuating, extraaxial hematoma. A subgroup of 21 patients in whom the EDH was located at the anterior aspect of the middle cranial fossa was defined. Computed tomographic images and inpatient medical records of these 21 patients were evaluated for imaging characteristics of the EDH, presence or absence of associated fracture, presence or absence of midline shift and/or mass effect, additional intracranial injury, and hospital clinical course. RESULTS: Twenty-one (10.5%) of 200 traumatic EDHs localized to the anterior middle cranial fossa. All of these 21 anterior temporal EDHs were juxtaposed to the sphenoparietal sinus, and all but one were limited laterally by the sphenotemporal suture and medially by the orbital fissure; none extended above the lesser sphenoid wing. Maximum thickness was less than 1 cm in 13 (62%) of 21 and less than 2 cm in 20 (95%) of 21 patients. Isolated fractures of the greater sphenoid wing and ipsilateral zygomaticomaxillary fractures were present in 12 (57%) of 21 and nine (43%) of 21 patients, respectively. Concomitant intracranial injury was identified in 15 (71%) of 21 patients. Twenty (95%) of 21 lesions were present at the admission study, and all 21 were stable or smaller at follow-up imaging. No patient required neurosurgical intervention of their anterior temporal EDH. CONCLUSION: Acute EDHs isolated to the anterior aspect of the middle cranial fossa constitute a subgroup of traumatic EDHs with a benign natural history. It is postulated that they arise from venous bleeding due to disruption of the sphenoparietal sinus.

Second-impact syndrome and a small subdural hematoma: an uncommon catastrophic result of repetitive head injury with a characteristic imaging appearance.

There have been a handful of previously published cases of athletes who were still symptomatic from a prior head injury, and then suffered a second injury in which a thin, acute subdural hematoma (SDH) with unilateral hemisphere vascular engorgement was demonstrated on CT scan. In those cases, the cause of the brain swelling/dysautoregulation was ascribed to the presence of the acute SDH rather than to the acceleration/deceleration forces that caused the SDH. We believe that the brain swelling is due to "second-impact dysautoregulation," rather than due to the effect of the SDH on the underlying hemisphere. To support our hypothesis, we present 10 additional cases of acute hemispheric swelling in association with small SDHs in athletes who received a second head injury while still symptomatic from a previous head injury. The clinical history and the unique neuroimaging features of this entity on CT are described and illustrated in detail. The CT findings included an engorged cerebral hemisphere with initial preservation of grey-white matter differentiation, and abnormal mass effect and midline shift that appeared disproportionately greater than the size of the SDH. In addition, the imaging similarities between our patients and those with non-accidental head trauma (shaken-baby syndrome) will be discussed.

Hemicraniectomy: a new model for human electrophysiology with high spatio-temporal resolution.

Human electrophysiological research is generally restricted to scalp EEG, magneto-encephalography, and intracranial electrophysiology. Here we examine a unique patient cohort that has undergone decompressive hemicraniectomy, a surgical procedure wherein a portion of the calvaria is removed for several months during which time the scalp overlies the brain without intervening bone. We quantify the differences in signals between electrodes over areas with no underlying skull and scalp EEG electrodes over the intact skull in the same subjects. Signals over the hemicraniectomy have enhanced amplitude and greater task-related power at higher frequencies (60-115 Hz) compared with signals over skull. We also provide evidence of a metric for trial-by-trial EMG/EEG coupling that is effective over the hemicraniectomy but not intact skull at frequencies >60 Hz. Taken together, these results provide evidence that the hemicraniectomy model provides a means for studying neural dynamics in humans with enhanced spatial and temporal resolution.

Neuroimaging of traumatic brain injury.

In this article, the neuroradiological evaluation of traumatic brain injury is reviewed. Different imaging strategies in the assessment of traumatic brain injury are initially discussed, and this is followed by a review of the imaging characteristics of both primary and secondary brain injuries. Computed tomography remains the modality of choice for the initial assessment of acute head injury because it is fast, widely available, and highly accurate in the detection of skull fractures and acute intracranial hemorrhage. Magnetic resonance imaging is recommended for patients with acute traumatic brain injury when the neurological findings are unexplained by computed tomography. Magnetic resonance imaging is also the modality of choice for the evaluation of subacute or chronic traumatic brain injury. Mild traumatic brain injury continues to be difficult to diagnose with current imaging technology. Advanced magnetic resonance techniques, such as diffusion-weighted imaging, magnetic resonance spectroscopy, and magnetization transfer imaging, can improve the identification of traumatic brain injury, especially in the case of mild traumatic brain injury. Further research is needed for other advanced imaging methods such as magnetic source imaging, single photon emission tomography, and positron emission tomography.

Clinical policy: neuroimaging and decisionmaking in adult mild traumatic brain injury in the acute setting.

This clinical policy provides evidence-based recommendations on select issues in the management of adult patients with mild traumatic brain injury (TBI) in the acute setting. It is the result of joint efforts between the American College of Emergency Physicians and the Centers for Disease Control and Prevention and was developed by a multidisciplinary panel. The critical questions addressed in this clinical policy are: (1) Which patients with mild TBI should have a noncontrast head computed tomography (CT) scan in the emergency department (ED)? (2) Is there a role for head magnetic resonance imaging over noncontrast CT in the ED evaluation of a patient with acute mild TBI? (3) In patients with mild TBI, are brain specific serum biomarkers predictive of an acute traumatic intracranial injury? (4) Can a patient with an isolated mild TBI and a normal neurologic evaluation result be safely discharged from the ED if a noncontrast head CT scan shows no evidence of intracranial injury? Inclusion criteria for application of this clinical policy's recommendations are nonpenetrating trauma to the head, presentation to the ED within 24 hours of injury, a Glasgow Coma Scale score of 14 or 15 on initial evaluation in the ED, and aged 16 years or greater. The primary outcome measure for questions 1, 2, and 3 is the presence of an acute intracranial injury on noncontrast head CT scan; the primary outcome measure for question 4 is the occurrence of neurologic deterioration.