Isodense subdural haematomas on CT:MRI findings

Imaging Findings in Acute Traumatic Brain Injury: a National Institute of Neurological Disorders and Stroke Common Data Element-Based Pictorial Review and Analysis of Over 4000 Admission Brain Computed Tomography Scans from the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) Study

In 2010, the National Institute of Neurological Disorders and Stroke (NINDS) created a set of common data elements (CDEs) to help standardize the assessment and reporting of imaging findings in traumatic brain injury (TBI). However, as opposed to other standardized radiology reporting systems, a visual overview and data to support the proposed standardized lexicon are lacking. We used over 4000 admission computed tomography (CT) scans of patients with TBI from the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) study to develop an extensive pictorial overview of the NINDS TBI CDEs, with visual examples and background information on individual pathoanatomical lesion types, up to the level of supplemental and emerging information (e.g., location and estimated volumes). We documented the frequency of lesion occurrence, aiming to quantify the relative importance of different CDEs for characterizing TBI, and performed a critical appraisal of our experience with the intent to inform updating of the CDEs. In addition, we investigated the co-occurrence and clustering of lesion types and the distribution of six CT classification systems. The median age of the 4087 patients in our dataset was 50 years (interquartile range, 29-66; range, 0-96), including 238 patients under 18 years old (5.8%). Traumatic subarachnoid hemorrhage (45.3%), skull fractures (37.4%), contusions (31.3%), and acute subdural hematoma (28.9%) were the most frequently occurring CT findings in acute TBI. The ranking of these lesions was the same in patients with mild TBI (baseline Glasgow Coma Scale [GCS] score 13-15) compared with those with moderate-severe TBI (baseline GCS score 3-12), but the frequency of occurrence was up to three times higher in moderate-severe TBI. In most TBI patients with CT abnormalities, there was co-occurrence and clustering of different lesion types, with significant differences between mild and moderate-severe TBI patients. More specifically, lesion patterns were more complex in moderate-severe TBI patients, with more co-existing lesions and more frequent signs of mass effect. These patients also had higher and more heterogeneous CT score distributions, associated with worse predicted outcomes. The critical appraisal of the NINDS CDEs was highly positive, but revealed that full assessment can be time consuming, that some CDEs had very low frequencies, and identified a few redundancies and ambiguity in some definitions. Whilst primarily developed for research, implementation of CDE templates for use in clinical practice is advocated, but this will require development of an abbreviated version. In conclusion, with this study, we provide an educational resource for clinicians and researchers to help assess, characterize, and report the vast and complex spectrum of imaging findings in patients with TBI. Our data provides a comprehensive overview of the contemporary landscape of TBI imaging pathology in Europe, and the findings can serve as empirical evidence for updating the current NINDS radiologic CDEs to version 3.0.

Chronic Subdural Hematoma (cSDH): A review of the current state of the art

Introduction

Incidence of Chronic Subdural Hematoma (cSDH) is rising worldwide, partly due to an aging population, but also due to increased use of antithrombotic medication. Many recent studies have emerged to address current cSDH management strategies.

Research question

What is the state of the art of cSDH management.

Material and methods

Review.

Results

Head trauma, antithrombotic use and craniocerebral disproportion increase the risk of cSDH development. Most patients present with disorientation, GCS 13–15, and symptoms arising from cortical irritation and increased intracranial pressure. cSDH occurs bilaterally in 9–22%. CT allows assessment of cerebral compression (herniation, hematoma thickness, ventricle collapse, midline shift), hematoma age and presence of membranes, factors that ultimately determine treatment urgency and surgical approach. Recurrence remains the principle complication (9–33%), occurring more commonly with older age and bilateral cSDHs.

Discussion and conclusion

While incompletely understood, it is generally believed that injury in the dural cell layer results in bleeding from bridging veins, resulting in a hematoma formation, with or without a preceding hygroma, in a potential space approximating the junction between the dura and arachnoid. Neovascularization and leaking from the outer membrane are thought to propagate this process. Evidence that MMA embolization may reduce recurrence rates is a potentially exciting new treatment option, but also supports the theory that the MMA is implicated in the cSDH pathophysiology. The use of steroids remains a controversial topic without clear treatment guidelines. cSDH represents a common neurosurgical problem with burr-hole treatment remaining the gold standard, often in conjunction with subgaleal drains. MMA embolization to stop recurrence may represent an important evolution in understanding the pathophysiology of cSDH and improving treatment.

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Incidence of cSDH is rising, partly due to the aging population and increased antithrombotic use.

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cSDH occurs bilaterally in 9–22% of cases.

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Recurrence remains the principle complication and has been estimated at 9–33%.

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Risk factors for recurrence include old age and bilateral cSDHs.

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MMA embolization may reduce recurrence, but its efficacy and target population remain unclear.

Heterogeneity of acute subdural collections: In search of a unifying feature

Introduction

A variety of different acute subdural hematoma patterns of density have been reported in the literature and are commonly seen in clinical practice, including rare hypodense acute subdural hematomas. It is unclear if these acute hypodense collections are entirely hypodense or if on close inspection, they can reveal subtle, tiny hyperdense components. The purpose of this study was to determine if all acute subdural hemtomas contain a hyperdense component, including seemingly entirely hypodense subdural collections.

Methods

Non-contrast CT scans of 111 patients containing 320 hyperacute or acute subdural collections were analyzed for the presence of a hyperdense component. Hounsfield measurements were recorded.

Results

All hyperacute and acute subdural hematomas in our study had a hyperdense component. Hyperacute subdural hematomas have a hyperdense component >97.5% of the time (95% confidence), and acute subdural hematomas have a hyperdense component >99% of the time (95% confidence).

Conclusion

Lack of a hyperdense component in a subdural hematoma makes acute or hyperacute hematoma highly unlikely, and alternative diagnoses should be considered.

CT Attenuation of Acute Subdural Hematomas in Patients with Anemia

BACKGROUND AND PURPOSE

Isodense and hypodense acute subdural hematomas have been reported in the literature in anemic patients. The purpose of this study is to see if there is a statistically significant difference between the Hounsfield unit measurements of acute subdural hematomas in anemic and nonanemic patients.

METHODS

A total of 109 patients were analyzed. We measured the most hyperdense component of the subdural hematoma and compared these measurements for both anemic and nonanemic patients.

RESULTS

All patients with anemia had a hyperdense component to their subdural hematomas during the acute period. No statistically significant difference was found in the density of the subdural hematomas between the two groups. More heterogeneous subdural hematomas were found in the anemic group than the nonanemic group, which suggests that anemia alone is not a sufficient explanation for acute homogenous isodense and hypodense subdural hematomas.

CONCLUSION

A hyperdense subdural component was present in all acute subdural hematomas in anemic patients. Therefore, anemia alone is not a sufficient explanation for a homogenous low-density acute subdural hematoma.

Role of neuroimaging in management of traumatic brain injury

Traumatic brain injury is a significant cause of morbidity and mortality in the UK with substantial associated economic costs to the healthcare system. This article explores the role of neuroimaging in both acute and long-term management of traumatic brain injury patients. We discuss the indications for urgent cross-section imaging as well as radiological features of both primary insults and secondary injuries. The role of neuroimaging in guiding surgical therapy and monitoring post-operative traumatic brain injury patients has also been described. Following initial injury, traumatic brain injury patients can suffer from a wide variety of physical, social and psychological difficulties. New techniques such as diffusion tensor imaging in combination with conventional magnetic resonance imaging sequences may provide useful information in predicting long-term prognosis and guiding rehabilitation.

Multiple Densities of the Chronic Subdural Hematoma in CT Scans

Objective

Density of the chronic subdural hematoma (cSDH) is variable. It often appears to be mixed density. Multiple densities of cSDH may result from multiple episodes of trauma. We investigated the frequency of mixed density and the causes of head injuries representing each density.

Methods

We could collect 242 cases of chronic SDH. The cSDHs were classified into four groups; hypodensity, homogeneous isodensity, layered type, and mixed type on the basis of CT scans.

Results

The density of cSDH was isodense in 115 patients, hypodense in 31 patients, mixed in 79 cases, and layered in 17 cases. The cSDH was on the left side in 115 patients, on the right side in 70 patients, and bilateral in 40 patients. The history of trauma was identifiable in 122 patients. The etiology could be identified in 67.7% of the hypodense hematomas, while it was obscure in 59.5% of the mixed hematomas.

Conclusion

Mixed density of cSDH results from multiple episodes of trauma, usually in the aged. It is hard to remember all the trivial traumas for the patients with the mixed density cSDHs. Although there were membranes within the mixed density hematomas, burr-holes were usually enough to drain the hematomas.

Acute-on-Chronic Subdural Hematoma: Not Uncommon Events

OBJECTIVE

Patients with asymptomatic chronic subdural hematoma (SDH) are prone to fall or slip. Acute trauma on these patients may develop acute subdural bleeding over the chronic SDH. We recently experienced 9 patients with acute-on-chronic SDH. We report the clinical and radiological features of this lesion.

METHODS

We retrospectively examined the computed tomographic (CT) scans of 107 consecutive patients who diagnosed as chronic SDH from January 2008 to December 2010. All cases of CSDH were diagnosed on CT with or without MRI scan.

RESULTS

Acute-on-chronic SDH is not rare, being 8% of chronic SDH. The most common cause of trauma was a slip in drunken state. Alcoholism with multiple episodes of trauma was one of the prominent histories. Acute-on-chronic SDH appeared as a hyperdense layer of clot with irregular blurred margin or lumps in liquefied hematoma. Single or two burr holes was usually effective to remove the hematoma.

CONCLUSION

Repeated trauma may cause acute bleeding over the chronic SDH. It will be helpful to understand the role of repeated trauma as a mechanism of hematoma enlargement.

The surgical management of chronic subdural hematoma

Chronic subdural hematoma (cSDH) is an increasingly common neurological disease process. Despite the wide prevalence of cSDH, there remains a lack of consensus regarding numerous aspects of its clinical management. We provide an overview of the epidemiology and pathophysiology of cSDH and discuss several controversial management issues, including the timing of post-operative resumption of anticoagulant medications, the effectiveness of anti-epileptic prophylaxis, protocols for mobilization following evacuation of cSDH, as well as the comparative effectiveness of the various techniques of surgical evacuation. A PubMed search was carried out through October 19, 2010 using the following keywords: "subdural hematoma", "craniotomy", "burr-hole", "management", "anticoagulation", "seizure prophylaxis", "antiplatelet", "mobilization", and "surgical evacuation", alone and in combination. Relevant articles were identified and back-referenced to yield additional papers. A meta-analysis was then performed comparing the efficacy and complications associated with the various methods of cSDH evacuation. There is general agreement that significant coagulopathy should be reversed expeditiously in patients presenting with cSDH. Although protocols for gradual resumption of anti-coagulation for prophylaxis of venous thrombosis may be derived from guidelines for other neurosurgical procedures, further prospective study is necessary to determine the optimal time to restart full-dose anti-coagulation in the setting of recently drained cSDH. There is also conflicting evidence to support seizure prophylaxis in patients with cSDH, although the existing literature supports prophylaxis in patients who are at a higher risk for seizures. The published data regarding surgical technique for cSDH supports primary twist drill craniostomy (TDC) drainage at the bedside for patients who are high-risk surgical candidates with non-septated cSDH and craniotomy as a first-line evacuation technique for cSDH with significant membranes. Larger prospective studies addressing these aspects of cSDH management are necessary to establish definitive recommendations.

Diffusion tensor imaging of mild traumatic brain injury

Mild traumatic brain injury (mTBI) remains a challenge to accurately assess with conventional neuroimaging. Recent research holds out the promise that diffusion tensor imaging (DTI) can be used to predict recovery in mTBI patients. Unlike computed tomography or conventional magnetic resonance imaging, DTI is sensitive to microstructural axonal injury, the neuropathology that is thought to be most responsible for the persistent cognitive and behavioral impairments that often occur after mTBI. Through the use of newer DTI analysis techniques such as automated region of interest analysis, tract-based voxel-wise analysis, and quantitative tractography, researchers have shown that frontal and temporal association white matter pathways are most frequently damaged in mTBI and that the microstructural integrity of these tracts correlates with behavioral and cognitive measures. Future longitudinal DTI studies are needed to elucidate how symptoms and the microstructural pathology evolve over time. Moving forward, large-scale investigations will ascertain whether DTI can serve as a predictive imaging biomarker for long-term neurocognitive deficits after mTBI that would be of value for triaging patients to clinical trials of experimental cognitive enhancement therapies and rehabilitation methods, as well as for monitoring their response to these interventions.

Membranectomy in organized chronic subdural hematomas: indications and technical notes

BACKGROUND

The aim of the present study is to present our operative method of removing organized CSDHs and to structure the criteria for choosing this approach as first treatment.

METHODS

Between 1991 and 1999 at our Institution, 14 consecutive patients with organized CSDHs required 16 craniotomies with membranectomy. They represent 5.8% of all patients (243) treated for CSDHs in the same period. All the patients had preoperative contrast-enhanced CT, and 9 patients also had contrast MRI.

RESULTS

Initially, 9 patients underwent one burr hole or twist-drill hole. Of these 9 patients, 3 were treated at the same surgery with craniotomy and membranectomy as second treatment, 3 underwent a second burr hole and then membranectomy at the same surgery, and 3 patients underwent a second burr hole 3, 4, and 21 days after the first one and then membranectomy. Five patients underwent immediate craniotomy and membranectomy. There were no morbidity or mortality associated with this procedure. All patients had a full recovery without recurrence.

CONCLUSIONS

Contrast-enhanced MRI has greatly improved opportunities for discovering neomembrane before surgical intervention. We believe that MRI detection of thick and extensive membranes or solid clot with mass effect makes an immediate craniotomy to remove CSDH necessary.

Quiste aracnoideo complicado con hemorragia intraquística y hematoma subdural espontáneo: hallazgos en resonancia magnética

Arachnoid cysts are collections of cerebrospinal fluid within the arachnoid membrane. They are benign lesions and most are congenital. They are usually asymptomatic; however, they can bleed and become symptomatic. Although arachnoid cyst associated to intracystic hemorrhage and spontaneous subdural hematoma is an uncommon complication, it is a well-known indication for emergency neurosurgery. We present the findings in a ten-year-old boy diagnosed with arachnoid cyst complicated by intracystic hemorrhage and spontaneous subdural hematoma diagnosed by magnetic resonance.

Neuroimaging in traumatic brain imaging

Traumatic brain injury (TBI) is a common and potentially devastating clinical problem. Because prompt proper management of TBI sequelae can significantly alter the clinical course especially within 48 h of the injury, neuroimaging techniques have become an important part of the diagnostic work up of such patients. In the acute setting, these imaging studies can determine the presence and extent of injury and guide surgical planning and minimally invasive interventions. Neuroimaging also can be important in the chronic therapy of TBI, identifying chronic sequelae, determining prognosis, and guiding rehabilitation.

New developments in the neuroradiological diagnosis of craniocerebral trauma

Accurate radiographic diagnosis is a cornerstone of the clinical management and outcome prediction of the head-injured patient. New technological advances, such as multi-detector computed tomography (MDCT) scanning and diffusion-weighted magnetic resonance imaging (MRI) have influenced imaging strategy. In this article we review the impact of these developments on the neuroradiological diagnosis of acute head injury. In the acute phase, multi-detector CT has supplanted plain X-ray films of the skull as the initial imaging study of choice. MRI, including fluid-attenuated inversion recovery, gradient echo T2* and diffusion-weighted sequences, is useful in determining the severity of acute brain tissue injury and may help to predict outcome. The role of MRI in showing diffuse axonal injuries is emphasized. We review the different patterns of primary and secondary extra-axial and intra-axial traumatic brain lesions and integrate new insights. Assessment of intracranial hypertension and cerebral herniation are of major clinical importance in patient management. We discuss the issue of pediatric brain trauma and stress the importance of MRI in non-accidental injury. In summary, new developments in imaging technology have advanced our understanding of the pathophysiology of brain trauma and contribute to improving the survival of patients with craniocerebral injuries.

Connective tissue reactions in subdural haematomas: imaging with contrast-enhancement MRI

The sensitivity of contrast enhanced magnetic resonance imaging (MRI) in the detection of connective tissue reactions accompanying the maturation of subdural haematomas (SDH) was studied. An outer enhancing layer between the SDH and the tabula interna of the vault was shown in 16 out of 17 cases. In early SDH this outer enhancing layer presumably is due to vascular congestion and/or increased vascular permeability. A thickening of the outer enhancing layer and/or an inner enhancing layer between the haematoma and the subarachnoid space was visible in 9 patients and represented a haematoma capsule formed by proliferating granulation tissue. In 5 SDH septations were found, 3 SDH consisted almost completely of enhancing granulation tissue. Thus, contrast enhanced MRI delivers additional information about the structure of SDH, which are useful for determining the extent of surgical treatment especially in chronic SDH.

Detection of bilateral isodense subdural haematomas

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