Brain lesions detected by magnetic resonance imaging in mild and severe head injuries

Heparan Sulfate Proteoglycans as Drivers of Neural Progenitors Derived From Human Mesenchymal Stem Cells

Background: Due to their relative ease of isolation and their high ex vivo and in vitro expansive potential, human mesenchymal stem cells (hMSCs) are an attractive candidate for therapeutic applications in the treatment of brain injury and neurological diseases. Heparan sulfate proteoglycans (HSPGs) are a family of ubiquitous proteins involved in a number of vital cellular processes including proliferation and stem cell lineage differentiation.

Methods: Following the determination that hMSCs maintain neural potential throughout extended in vitro expansion, we examined the role of HSPGs in mediating the neural potential of hMSCs. hMSCs cultured in basal conditions (undifferentiated monolayer cultures) were found to co-express neural markers and HSPGs throughout expansion with modulation of the in vitro niche through the addition of exogenous HS influencing cellular HSPG and neural marker expression.

Results: Conversion of hMSCs into hMSC Induced Neurospheres (hMSC IN) identified distinctly localized HSPG staining within the spheres along with altered gene expression of HSPG core protein and biosynthetic enzymes when compared to undifferentiated hMSCs.

Conclusion: Comparison of markers of pluripotency, neural self-renewal and neural lineage specification between hMSC IN, hMSC and human neural stem cell (hNSC H9) cultures suggest that in vitro generated hMSC IN may represent an intermediary neurogenic cell type, similar to a common neural progenitor cell. In addition, this data demonstrates HSPGs and their biosynthesis machinery, are associated with hMSC IN formation. The identification of specific HSPGs driving hMSC lineage-specification will likely provide new markers to allow better use of hMSCs in therapeutic applications and improve our understanding of human neurogenesis.

Both hemorrhagic and non-hemorrhagic traumatic MRI lesions are associated with the microstructural damage of the normal appearing white matter

Traumatic microbleeds (TMBs) and non-hemorrhagic lesions (NHLs) on MRI are regarded as surrogate markers of diffuse axonal injury. However, the actual relation between lesional and diffuse pathology remained unclear, since lesions were related to clinical parameters, largely influenced by extracranial factors. The aim of this study is to directly compare TMBs, NHLs and their regional features with the co-existing diffuse injury of the normal appearing white matter (NAWM) as measured by diffusion tensor imaging (DTI). Thirty-eight adults with a closed traumatic brain injury (12 mild, 4 moderate and 22 severe) who underwent susceptibility weighted imaging (SWI), T1-, T2 weighted and FLAIR MRI and routine CT were included in the study. TMB (on SWI) and NHL (on T1-, T2 weighted and FLAIR images) features and Rotterdam scores were evaluated. DTI metrics such as fractional anisotropy (FA) and mean diffusivity (MD) were measured over different NAWM regions. Clinical parameters including age; Glasgow Coma Scale; Rotterdam score; TMB and NHL features were correlated to regional NAWM diffusivity using multiple regression. Overall NHL presence and basal ganglia area TMB load were significantly, negatively correlated with the subcortical NAWM FA values (partial r=-0.37 and -0.36; p=0.006 and 0.025, respectively). The presence of any NHL, or TMBs located in the basal ganglia area indicates diffuse NAWM damage even after adjusting for clinical and CT parameters. To estimate DAI, a conventional lesional MRI pathology evaluation might at least in part substitute the use of quantitative DTI, which is yet not widely feasible in a clinical setting.

The Role of Magnetic Resonance Imaging in the Prediction of Minimally Conscious State After Traumatic Brain Injury

OBJECTIVE

To establish a simple and feasible model of magnetic resonance imaging (MRI) for prediction of minimally conscious state in unconscious patients (≥2 weeks) after severe traumatic brain injury (TBI).

METHODS

MRI examinations were performed in 73 patients 4.5 weeks ± 1.6 (range, 2-8 weeks) after TBI. Brain lesions on MRI, age, sex, cause of injury, Glasgow Coma Scale (GCS) score, and decompressive craniectomy were retrospectively analyzed. Outcome was assessed at 12 months from the onset of TBI.

RESULTS

Of 73 patients, 39 were minimally conscious and 34 were unconscious at the endpoint. Binary logistic regression demonstrated that cause of injury (P = 0.036), GCS score (P = 0.011), and lesions of the thalamus (P = 0.002) and brainstem (P = 0.012) shown on MRI were closely associated with the outcome of minimally conscious state. The overall correct prediction of the logistic model was 90.4%.

CONCLUSIONS

The combination of MRI findings and other clinical data offers neurosurgeons substantial information about primary and secondary injuries of the patients with TBI, which allows a more accurate prediction of prognosis than a single GCS score or MRI findings alone. The regression model established in this study is simple and effective in predicting long-term unconscious state and minimally conscious state in patients after severe TBI.

Grey matter brain injuries are common in Ugandan children with cerebral palsy suggesting a perinatal aetiology in full-term infants

AIM

There is limited literature on brain imaging studies of children with cerebral palsy (CP) in low and middle income countries. We investigated neuroimaging patterns of children with CP attending a tertiary referral centre in Uganda to determine how they differed from studies reported from high income countries and their relationship with prenatal and postnatal factors.

METHODS

Precontrast and postcontrast computed tomography (CT) scans of 78 CP children aged 2-12 years were conducted using a Philips MX 16-slice CT scanner. Two radiologists, blinded to the patient's clinical status, independently reviewed the scans.

RESULTS

Abnormal CT scans were detected in 69% of the children sampled, with very few having primary white matter injuries (4%). Primary grey matter injuries (PGMI) (44%) and normal scans (31%) were most frequent. Children with a history of hospital admission following birth were three times more likely to have PGMI (odds ratio [OR] 2.8; 95% CI 1.1-7.1), suggesting a perinatal period with medical complications.

CONCLUSION

Brain imaging patterns in this group of CP children differed markedly from imaging studies reported from high income countries, suggesting a perinatal aetiology in full-term infants and reduced survival in preterm infants.

Imaging minor head injury (MHI) in emergency radiology: MRI highlights additional intracranial findings after measurement of trauma biomarker S-100B in patients with normal CCT

OBJECTIVE

To investigate whether MRI in emergency radiology can detect (a) additional trauma-related findings after minor head injury (MHI) or (b) structural, non-trauma-related intracranial lesions when trauma biomarker S-100B concentration is raised, or clinical symptoms are unexplained, or both.

METHODS

41 patients with MHI were included. Concentrations of S-100B in serum were measured and categorized using an established cut-off at 0.1 μg l(-1). Intracerebral trauma-related as well as non-trauma-related chronic structural findings (atrophy, microangiopathy and chronic parenchymal defects) were assessed by cranial CT (CCT) and MRI by two independent radiologists (UL and LLG). All CCT and MRI results were compared with biomarker S-100B.

RESULTS

Compared with CCT, MRI detected 10 additional lesions. 5 patients had abnormal MRI with a total of 15 trauma-related lesions and showed elevated S-100B concentrations. Although sensitivity of S-100B was 100%, specificity was only 25%. Patients with structural brain lesions showed significantly higher S-100B serum levels (0.50 and 0.14 μg l(-1), p = 0.01).

CONCLUSION

Biomarker S-100B has proven its high negative-predictive value to rule out intracranial bleeding in patients after MHI even if MRI is used as imaging modality. Regarding the low specificity of S-100B, structural lesions of the brain parenchyma not related to the acute trauma may be associated with increased serum concentrations of protein S-100B.

ADVANCES IN KNOWLEDGE

Biomarker S-100B has a high negative-predictive value to rule out intracranial bleeding after MHI. Biomarker S-100B's low specificity may be associated with non-traumatic brain parenchyma lesions. MRI is superior to CCT in detecting subtle findings in neuroimaging after MHI. Biomarker S-100B can potentially reduce the large number of normal CCT studies after MHI.

Minimizing Radiation Exposure in Evaluation of Pediatric Head Trauma: Use of Rapid MR Imaging

BACKGROUND AND PURPOSE

With >473,000 annual emergency department visits for children with traumatic brain injuries in the United States, the risk of ionizing radiation exposure during CT examinations is a real concern. The purpose of this study was to assess the validity of rapid MR imaging to replace CT in the follow-up imaging of patients with head trauma.

MATERIALS AND METHODS

A retrospective review of 103 pediatric patients who underwent initial head CT and subsequent follow-up rapid MR imaging between January 2010 and July 2013 was performed. Patients had minor head injuries (Glasgow Coma Scale, >13) that required imaging. Initial head CT was performed, with follow-up rapid MR imaging completed within 48 hours. A board-certified neuroradiologist, blinded to patient information and scan parameters, then independently interpreted the randomized cases.

RESULTS

There was almost perfect agreement in the ability to detect extra-axial hemorrhage on rapid MR imaging and CT (κ = 0.84, P < .001). Evaluation of hemorrhagic contusion/intraparenchymal hemorrhage demonstrated a moderate level of agreement between MR imaging and CT (κ = 0.61, P < .001). The ability of MR imaging to detect a skull fracture also showed a substantial level of agreement with CT (κ = 0.71, P < .001). Detection of diffuse axonal injury demonstrated a slight level of agreement between MR imaging and CT (κ = 0.154, P = .04). However, the overall predictive agreement for the detection of an axonal injury was 91%.

CONCLUSIONS

Rapid MR imaging is a valid technique for detecting traumatic cranial injuries and an adequate examination for follow-up imaging in lieu of repeat CT.

Predicting Outcome after Pediatric Traumatic Brain Injury by Early Magnetic Resonance Imaging Lesion Location and Volume

Brain lesions after traumatic brain injury (TBI) are heterogeneous, rendering outcome prognostication difficult. The aim of this study is to investigate whether early magnetic resonance imaging (MRI) of lesion location and lesion volume within discrete brain anatomical zones can accurately predict long-term neurological outcome in children post-TBI. Fluid-attenuated inversion recovery (FLAIR) MRI hyperintense lesions in 63 children obtained 6.2±5.6 days postinjury were correlated with the Glasgow Outcome Scale Extended-Pediatrics (GOS-E Peds) score at 13.5±8.6 months. FLAIR lesion volume was expressed as hyperintensity lesion volume index (HLVI)=(hyperintensity lesion volume / whole brain volume)×100 measured within three brain zones: zone A (cortical structures); zone B (basal ganglia, corpus callosum, internal capsule, and thalamus); and zone C (brainstem). HLVI-total and HLVI-zone C predicted good and poor outcome groups (p<0.05). GOS-E Peds correlated with HLVI-total (r=0.39; p=0.002) and HLVI in all three zones: zone A (r=0.31; p<0.02); zone B (r=0.35; p=0.004); and zone C (r=0.37; p=0.003). In adolescents ages 13-17 years, HLVI-total correlated best with outcome (r=0.5; p=0.007), whereas in younger children under the age of 13, HLVI-zone B correlated best (r=0.52; p=0.001). Compared to patients with lesions in zone A alone or in zones A and B, patients with lesions in all three zones had a significantly higher odds ratio (4.38; 95% confidence interval, 1.19-16.0) for developing an unfavorable outcome.

Minor and repetitive head injury

Traumatic brain injury (TBI) is the leading cause of death and disability in the young, active population and expected to be the third leading cause of death in the whole world until 2020. The disease is frequently referred to as the silent epidemic, and many authors highlight the "unmet medical need" associated with TBI.The term traumatically evoked brain injury covers a heterogeneous group ranging from mild/minor/minimal to severe/non-salvageable damages. Severe TBI has long been recognized to be a major socioeconomical health-care issue as saving young lives and sometimes entirely restituting health with a timely intervention can indeed be extremely cost efficient.Recently it has been recognized that mild or minor TBI should be considered similarly important because of the magnitude of the patient population affected. Other reasons behind this recognition are the association of mild head injury with transient cognitive disturbances as well as long-term sequelae primarily linked to repeat (sport-related) injuries.The incidence of TBI in developed countries can be as high as 2-300/100,000 inhabitants; however, if we consider the injury pyramid, it turns out that severe and moderate TBI represents only 25-30 % of all cases, while the overwhelming majority of TBI cases consists of mild head injury. On top of that, or at the base of the pyramid, are the cases that never show up at the ER - the unreported injuries.Special attention is turned to mild TBI as in recent military conflicts it is recognized as "signature injury."This chapter aims to summarize the most important features of mild and repetitive traumatic brain injury providing definitions, stratifications, and triage options while also focusing on contemporary knowledge gathered by imaging and biomarker research.Mild traumatic brain injury is an enigmatic lesion; the classification, significance, and its consequences are all far less defined and explored than in more severe forms of brain injury.Understanding the pathobiology and pathomechanisms may aid a more targeted approach in triage as well as selection of cases with possible late complications while also identifying the target patient population where preventive measures and therapeutic tools should be applied in an attempt to avoid secondary brain injury and late complications.

Prospective longitudinal MRI study of brain volumes and diffusion changes during the first year after moderate to severe traumatic brain injury

The objectives of this prospective study in 62 moderate–severe TBI patients were to investigate volume change in cortical gray matter (GM), hippocampus, lenticular nucleus, lobar white matter (WM), brainstem and ventricles using a within subject design and repeated MRI in the early phase (1–26 days) and 3 and 12 months postinjury and to assess changes in GM apparent diffusion coefficient (ADC) in normal appearing tissue in the cortex, hippocampus and brainstem. The impact of Glasgow Coma Scale (GCS) score at admission, duration of post-traumatic amnesia (PTA), and diffusion axonal injury (DAI) grade on brain volumes and ADC values over time was assessed. Lastly, we determined if MRI-derived brain volumes from the 3-month scans provided additional, significant predictive value to 12-month outcome classified with the Glasgow Outcome Scale—Extended after adjusting for GCS, PTA and age.

Cortical GM loss was rapid, largely finished by 3 months, but the volume reduction was unrelated to GCS score, PTA, or presence of DAI. However, cortical GM volume at 3 months was a significant independent predictor of 12-month outcome. Volume loss in the hippocampus and lenticular nucleus was protracted and statistically significant first at 12 months. Slopes of volume reduction over time for the cortical and subcortical GGM were significantly different. Hippocampal volume loss was most pronounced and rapid in individuals with PTA > 2 weeks. The 3-month volumes of the hippocampus and lentiform nucleus were the best independent predictors of 12-month outcome after adjusting for GCS, PTA and age. In the brainstem, volume loss was significant at both 3 and 12 months. Brainstem volume reduction was associated with lower GCS score and the presence of DAI. Lobar WM volume was significantly decreased first after 12 months. Surprisingly DAI grade had no impact on lobar WM volume. Ventricular dilation developed predominantly during the first 3 months, and was strongly associated with volume changes in the brainstem and cortical GM, but not lobar WM volume.

Higher ADC values were detected in the cortex in individuals with severe TBI, DAI and PTA > 2 weeks, from 3 months. There were no associations between ADC values and brain volumes, and ADC values did not predict outcome.

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Longitudinal study of brain volume changes following TBI

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3 month MRI derived volumes are independent predictors of outcome at 12 months.

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PTA, GCS and DAI have different impacts on different brain volumes.

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Subcortical and cortical GM volume losses follow significantly different trajectories.

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Significant changes in cortical ADC values develop slowly while volume changes are rapid.

Concussive injury before or after controlled cortical impact exacerbates histopathology and functional outcome in a mixed traumatic brain injury model in mice

Traumatic brain injury (TBI) may involve diverse injury mechanisms (e.g., focal impact vs. diffuse impact loading). Putative therapies developed in TBI models featuring a single injury mechanism may fail in clinical trials if the model does not fully replicate multiple injury subtypes, which may occur concomitantly in a given patient. We report development and characterization of a mixed contusion/concussion TBI model in mice using controlled cortical impact (CCI; 0.6 mm depth, 6 m/sec) and a closed head injury (CHI) model at one of two levels of injury (53 vs. 83 g weight drop from 66 in). Compared with CCI or CHI alone, sequential CCI-CHI produced additive effects on loss of consciousness (p<0.001), acute cell death (p<0.05), and 12-day lesion size (p<0.05) but not brain edema or 48-h contusion volume. Additive effects of CHI and CCI on post-injury motor (p<0.05) and cognitive (p<0.005) impairment were observed with sequential CCI-CHI (83 g). The data suggest that concussive forces, which in isolation do not induce histopathological damage, exacerbate histopathology and functional outcome after cerebral contusion. Sequential CHI-CCI may model complex injury mechanisms that occur in some patients with TBI and may prove useful for testing putative therapies.

Magnetic resonance imaging improves 3-month outcome prediction in mild traumatic brain injury

OBJECTIVE

To determine the clinical relevance, if any, of traumatic intracranial findings on early head computed tomography (CT) and brain magnetic resonance imaging (MRI) to 3-month outcome in mild traumatic brain injury (MTBI).

METHODS

One hundred thirty-five MTBI patients evaluated for acute head injury in emergency departments of 3 LEVEL I trauma centers were enrolled prospectively. In addition to admission head CT, early brain MRI was performed 12 ± 3.9 days after injury. Univariate and multivariate logistic regression were used to assess for demographic, clinical, socioeconomic, CT, and MRI features that were predictive of Extended Glasgow Outcome Scale (GOS-E) at 3 months postinjury.

RESULTS

Twenty-seven percent of MTBI patients with normal admission head CT had abnormal early brain MRI. CT evidence of subarachnoid hemorrhage was associated with a multivariate odds ratio of 3.5 (p = 0.01) for poorer 3-month outcome, after adjusting for demographic, clinical, and socioeconomic factors. One or more brain contusions on MRI, and ≥4 foci of hemorrhagic axonal injury on MRI, were each independently associated with poorer 3-month outcome, with multivariate odds ratios of 4.5 (p = 0.01) and 3.2 (p = 0.03), respectively, after adjusting for head CT findings and demographic, clinical, and socioeconomic factors.

INTERPRETATION

In this prospective multicenter observational study, the clinical relevance of abnormal findings on early brain imaging after MTBI is demonstrated. The addition of early CT and MRI markers to a prognostic model based on previously known demographic, clinical, and socioeconomic predictors resulted in a >2-fold increase in the explained variance in 3-month GOS-E.

Multiple resting state network functional connectivity abnormalities in mild traumatic brain injury

Several reports show that traumatic brain injury (TBI) results in abnormalities in the coordinated activation among brain regions. Because most previous studies examined moderate/severe TBI, the extensiveness of functional connectivity abnormalities and their relationship to postconcussive complaints or white matter microstructural damage are unclear in mild TBI. This study characterized widespread injury effects on multiple integrated neural networks typically observed during a task-unconstrained "resting state" in mild TBI patients. Whole brain functional connectivity for twelve separate networks was identified using independent component analysis (ICA) of fMRI data collected from thirty mild TBI patients mostly free of macroscopic intracerebral injury and thirty demographically-matched healthy control participants. Voxelwise group comparisons found abnormal mild TBI functional connectivity in every brain network identified by ICA, including visual processing, motor, limbic, and numerous circuits believed to underlie executive cognition. Abnormalities not only included functional connectivity deficits, but also enhancements possibly reflecting compensatory neural processes. Postconcussive symptom severity was linked to abnormal regional connectivity within nearly every brain network identified, particularly anterior cingulate. A recently developed multivariate technique that identifies links between whole brain profiles of functional and anatomical connectivity identified several novel mild TBI abnormalities, and represents a potentially important new tool in the study of the complex neurobiological sequelae of TBI.

Management of minor head injury: the value of early computed tomography and serum protein S-100 measurements

Computed tomography (CT) scan was performed within 6 h in 91 patients with minor head injury (MHI). Eight patients (9%) demonstrated intracranial lesions on CT scan (6 brain contusions, 1 brain edema and 1 extradural hematoma). No patient required craniotomy. In patients with normal CT scan, no complications to the head injury were observed. Patients with intracranial lesions were hospitalized significantly longer (mean 9.4 days) than patients without (mean 1.6 days). In a subgroup of 50 patients with normal CT scan, serum S-100 protein was measured on admission. Elevated S-100 levels were seen in 10 of 50 patients (0.5-2.4 mug/L, mean 1.1). These patients were hospitalized significantly longer (mean 3.4 days) compared to patients with normal CT scan and normal S-100 levels (mean 1.1 days). MHI patients with GCS 14-15 without neurological deficits can safely be discharged when CT scan is normal. Serum protein S-100 measurements appear to provide information about diffuse brain injury after MHI.

A review of magnetic resonance imaging and diffusion tensor imaging findings in mild traumatic brain injury

Mild traumatic brain injury (mTBI), also referred to as concussion, remains a controversial diagnosis because the brain often appears quite normal on conventional computed tomography (CT) and magnetic resonance imaging (MRI) scans. Such conventional tools, however, do not adequately depict brain injury in mTBI because they are not sensitive to detecting diffuse axonal injuries (DAI), also described as traumatic axonal injuries (TAI), the major brain injuries in mTBI. Furthermore, for the 15 to 30 % of those diagnosed with mTBI on the basis of cognitive and clinical symptoms, i.e., the "miserable minority," the cognitive and physical symptoms do not resolve following the first 3 months post-injury. Instead, they persist, and in some cases lead to long-term disability. The explanation given for these chronic symptoms, i.e., postconcussive syndrome, particularly in cases where there is no discernible radiological evidence for brain injury, has led some to posit a psychogenic origin. Such attributions are made all the easier since both posttraumatic stress disorder (PTSD) and depression are frequently co-morbid with mTBI. The challenge is thus to use neuroimaging tools that are sensitive to DAI/TAI, such as diffusion tensor imaging (DTI), in order to detect brain injuries in mTBI. Of note here, recent advances in neuroimaging techniques, such as DTI, make it possible to characterize better extant brain abnormalities in mTBI. These advances may lead to the development of biomarkers of injury, as well as to staging of reorganization and reversal of white matter changes following injury, and to the ability to track and to characterize changes in brain injury over time. Such tools will likely be used in future research to evaluate treatment efficacy, given their enhanced sensitivity to alterations in the brain. In this article we review the incidence of mTBI and the importance of characterizing this patient population using objective radiological measures. Evidence is presented for detecting brain abnormalities in mTBI based on studies that use advanced neuroimaging techniques. Taken together, these findings suggest that more sensitive neuroimaging tools improve the detection of brain abnormalities (i.e., diagnosis) in mTBI. These tools will likely also provide important information relevant to outcome (prognosis), as well as play an important role in longitudinal studies that are needed to understand the dynamic nature of brain injury in mTBI. Additionally, summary tables of MRI and DTI findings are included. We believe that the enhanced sensitivity of newer and more advanced neuroimaging techniques for identifying areas of brain damage in mTBI will be important for documenting the biological basis of postconcussive symptoms, which are likely associated with subtle brain alterations, alterations that have heretofore gone undetected due to the lack of sensitivity of earlier neuroimaging techniques. Nonetheless, it is noteworthy to point out that detecting brain abnormalities in mTBI does not mean that other disorders of a more psychogenic origin are not co-morbid with mTBI and equally important to treat. They arguably are. The controversy of psychogenic versus physiogenic, however, is not productive because the psychogenic view does not carefully consider the limitations of conventional neuroimaging techniques in detecting subtle brain injuries in mTBI, and the physiogenic view does not carefully consider the fact that PTSD and depression, and other co-morbid conditions, may be present in those suffering from mTBI. Finally, we end with a discussion of future directions in research that will lead to the improved care of patients diagnosed with mTBI.

Severe traumatic head injury: prognostic value of brain stem injuries detected at MRI

BACKGROUND AND PURPOSE

Traumatic brain injuries represent an important cause of death for young people. The main objectives of this work are to correlate brain stem injuries detected at MR imaging with outcome at 6 months in patients with severe TBI, and to determine which MR imaging findings could be related to a worse prognosis.

MATERIALS AND METHODS

One hundred and eight patients with severe TBI were studied by MR imaging in the first 30 days after trauma. Brain stem injury was categorized as anterior or posterior, hemorrhagic or nonhemorrhagic, and unilateral or bilateral. Outcome measures were GOSE and Barthel Index 6 months postinjury. The relationship between MR imaging findings of brain stem injuries, outcome, and disability was explored by univariate analysis. Prognostic capability of MR imaging findings was also explored by calculation of sensitivity, specificity, and area under the ROC curve for poor and good outcome.

RESULTS

Brain stem lesions were detected in 51 patients, of whom 66% showed a poor outcome, as expressed by the GOSE scale. Bilateral involvement was strongly associated with poor outcome (P < .05). Posterior location showed the best discriminatory capability in terms of outcome (OR 6.8, P < .05) and disability (OR 4.8, P < .01). The addition of nonhemorrhagic and anterior lesions or unilateral injuries showed the highest odds and best discriminatory capacity for good outcome.

CONCLUSIONS

The prognosis worsens in direct relationship to the extent of traumatic injury. Posterior and bilateral brain stem injuries detected at MR imaging are poor prognostic signs. Nonhemorrhagic injuries showed the highest positive predictive value for good outcome.

The Assessment of Executive Functioning Following Mild Traumatic Brain Injury

The assessment of executive functioning 1 month following a mild traumatic brain injury (MTBI) is minimal, inconsistent and difficult to integrate. Four executive processes of checking, inhibition, sharing and integrating were examined using an empirically derived assessment protocol based on executive process delineation (Baddeley & Della Sala, 1998). This protocol was administered to individuals at 1 month post-MTBI (n= 22), and a group of orthopaedic controls (n= 15) matched for age, sex, years of education and occupational status. Contrary to expectations, only one significant difference between the two groups occurred on the dual-task Telephone Search while Counting (p< .006), which was considered a measure of the executive process of sharing. Methodological limitations such as a small and heterogeneous sample may have influenced the findings in this study. The results provide support for the utility of a theoretically driven approach to executive functioning to aid the integration of neuropsychological results, and highlight the need for carefully controlled research at 1 month following a MTBI to further delineate the recovery process.

Predictive value of clinical and radiological findings in inflicted traumatic brain injury

AIMS

The aim of this study is to evaluate the value of early radiological investigations in predicting the long-term neurodevelopmental outcome of infants with inflicted traumatic brain injury (ITBI).

METHODS

Clinical and radiological investigations of 24 infants with ITBI were performed during the acute phase of injury (1-3 days), and during the early (4 days up to 3 months) and late (>9 months) postinjury phases. The clinical outcome in survivors (n = 22) was based on the Rankin Disability Scale and the Glasgow Outcome Score.

RESULTS

Five out of 24 infants (21%) had a poor neurodevelopmental outcome (death and severe disability), 17 infants (71%) had different developmental problems and 2 infants were normal at the mean age of 62 (54-70) (95% CI) months. A low initial Glasgow Coma Scale score of 8 or below [p < 0.05, OR 13.0 (1.3-133.3)], the development of brain oedema [p < 0.005, OR 13.0 (1.6-773)], focal changes in the basal ganglia during the acute phase [p < 0.01, OR 45 (2.1-937.3)], the development of new intracerebral focal changes early postinjury [p < 0.05, OR 24.1(1.0-559.1)], a decrease in white matter [p < 0.01, OR 33 (1.37-793.4)] and the development of severe atrophy before 3 months postinjury [p < 0.05, OR 24 (11.0-559.1)] were significantly correlated with a poor neurodevelopmental outcome.

CONCLUSIONS

Early clinical and radiological findings in ITBI are of prognostic value for neurodevelopmental outcome.

Traumatic brain injury, major depression, and diffusion tensor imaging: making connections

It is common for depression to develop after traumatic brain injury (TBI), yet despite poorer recovery, there is a lack in our understanding of whether post-TBI brain changes involved in depression are akin to those in people with depression without TBI. Modern neuroimaging has helped recognize degrees of diffuse axonal injury (DAI) as being related to extent of TBI, but its ability to predict long-term functioning is limited and has not been considered in the context of post-TBI depression. A more recent brain imaging technique (diffusion tensor imaging; DTI) can measure the integrity of white matter by measuring the directionality or anisotropy of water molecule diffusion along the axons of nerve fibers.

AIM

To review DTI results in the TBI and depression literatures to determine whether this can elucidate the etiology of the development of depression after TBI.

METHOD

We reviewed the TBI/DTI (40 articles) and depression/DTI literatures (17 articles). No articles were found that used DTI to investigate depression post-TBI, although there were some common brain regions identified between the TBI/DTI and depression/DTI studies, including frontotemporal, corpus callosum, and structures contained within the basal ganglia. Specifically, the internal capsule was commonly reported to have significantly reduced fractional anisotropy, which agrees with deep brain stimulation studies.

CONCLUSION

It is suggested that measuring the degree of DAI by utilizing DTI in those with or without depression post-TBI, will greatly enhance prediction of functional outcome.

fMRI study of problem-solving after severe traumatic brain injury

OBJECTIVE

To assess the cerebral correlates of the dysexecutive syndrome after diffuse severe traumatic brain injury (TBI).

METHODS

Ten patients with sub-acute/chronic severe TBI without detectable focal cortical contusion and 11 matched healthy subjects were included in a parametric fMRI study using a planning task, the Tower of London.

RESULTS

Brain activation in the left Dorsolateral Pre-frontal Cortex (DLPFC) and the Anterior Cingulate Cortex (ACC) was closely related to performance. Patients with TBI who performed the task efficiently showed, like healthy controls who obtained a similar pattern of performance, a large activation in the left DLPFC and a small activation in the ACC. In contrast, poor performance was associated with a reduced activation in these both regions.

CONCLUSION

Problem-solving deficits after severe diffuse TBI could be related to an impaired activation of the DLPFC and of the ACC.

The effects of mild traumatic brain injury on confrontation naming in adults

PRIMARY OBJECTIVE

To compare confrontation-naming in adults with MTBI to a group of normal adults under increased processing load conditions.

RESEARCH DESIGN

A randomized block, repeated measures design was used to examine confrontation-naming response latency and accuracy using a computerized experimental program.

METHODS AND PROCEDURES

Twenty-four adults having sustained a MTBI (aged 18-53) and 24 age-matched controls named pictures from three levels of vocabulary as quickly and accurately as possible. All MTBI participants were assessed with the Scales of Cognitive Ability for Traumatic Brain Injury (SCATBI) for later comparison.

MAIN OUTCOMES AND RESULTS

The results revealed a main effect of group ( p < or = 0.001) for the latency data and a group by vocabulary level interaction ( p = 0.043) for the accuracy data. No significant correlations were found between response latency and accuracy with performance on the SCATBI. Reaction time measures may reveal inefficiencies not tapped by traditional measures.

Clinical review: Prognostic value of magnetic resonance imaging in acute brain injury and coma

Progress in management of critically ill neurological patients has led to improved survival rates. However, severe residual neurological impairment, such as persistent coma, occurs in some survivors. This raises concerns about whether it is ethically appropriate to apply aggressive care routinely, which is also associated with burdensome long-term management costs. Adapting the management approach based on long-term neurological prognosis represents a major challenge to intensive care. Magnetic resonance imaging (MRI) can show brain lesions that are not visible by computed tomography, including early cytotoxic oedema after ischaemic stroke, diffuse axonal injury after traumatic brain injury and cortical laminar necrosis after cardiac arrest. Thus, MRI increases the accuracy of neurological diagnosis in critically ill patients. In addition, there is some evidence that MRI may have potential in terms of predicting outcome. Following a brief description of the sequences used, this review focuses on the prognostic value of MRI in patients with traumatic brain injury, anoxic/hypoxic encephalopathy and stroke. Finally, the roles played by the main anatomical structures involved in arousal and awareness are discussed and avenues for future research suggested.

The Acute Effects of Mild Traumatic Brain Injury on Finger Tapping With and Without Word Repetition

This study aimed to investigate the acute effects of mild Traumatic Brain Injury (mTBI) on the performance of a finger tapping and word repetition dual task in order to determine working memory impairment in mTBI. Sixty-four (50 male, 14 female) right-handed cases of mTBI and 26 (18 male and 8 female) right-handed cases of orthopaedic injuries were tested within 24 hours of injury. Patients with mTBI completed fewer correct taps in 10 seconds than patients with orthopaedic injuries, and female mTBI cases repeated fewer words. The size of the dual task decrement did not vary between groups. When added to a test battery including the Rapid Screen of Concussion (RSC; Comerford, Geffen, May, Medland & Geffen, 2002) and the Digit Symbol Substitution Test, finger tapping speed accounted for 1% of between groups variance and did not improve classification rates of male participants. While the addition of tapping rate did not improve the sensitivity and specificity of the RSC and DSST to mTBI in males, univariate analysis of motor performance in females indicated that dual task performance might be diagnostic. An increase in female sample size is warranted. These results confirm the view that there is a generalized slowing of processing ability following mTBI.

MR imaging of head trauma: visibility of contusions and other intraparenchymal injuries in early and late stage

The aim of this study was to investigate the visibility of traumatic brain lesions on conventional magnetic resonance images (MRI) in early and late phase. Thirty-six patients were studied 1 week and 1 year after a traumatic brain injury. A similar MRI technique was used in both studies; T2-weighted fast or turbo spin echo images, fluid attenuated inversion recovery (FLAIR) images and T1-weighted images were used for analysis. The number and extent of contusions and semi-quantitative score of other traumatic intraparenchymal lesions were compared in the early and late phase. Contusions were seen in 18 patients both in acute and 1 year MRI; the number and extent of visible contusions was significantly decreased at 1 year. Other traumatic intraparenchymal lesions were detected in 12 patients in early MRI and in 10 patients in late MRI. The number of visible lesions and the semi-quantitative scores were significantly lower at 1 year. There is a significant decrease in the visibility of both cortical contusions and other intraparenchymal injuries in late MRI studies compared with studies in acute stage using conventional imaging techniques. Thus, early phase MRI is essential for the detection of brain injury at least using conventional imaging techniques.

The Influence of an Auditory Distraction on Rapid Naming After a Mild Traumatic Brain Injury: A Longitudinal Study

OBJECTIVE

The purpose of this investigation was to examine speeded performance over time and the impact of a common auditory distraction on performance after a mild traumatic brain injury (MTBI).

METHODS

Fourteen adults (ages 18-53) treated for a MTBI and 14 age and education-matched controls were asked to perform two speeded naming tasks. Both tasks were presented with or without the presence a common auditory distraction. The MTBI group was tested within 5 days, 30 days, 60 days, and 6 months postinjury. Latency (ms) and accuracy of response were recorded.

RESULTS

Initially, the MTBI group demonstrated significantly longer response latencies and lower accuracy levels for both tasks. Similar results were found at 30 days postinjury. At 60 days postinjury, no significant difference was found for task 1 accuracy. Significant differences remained for task 1 latency, task 2 latency, and task 2 accuracy. At 6 months postinjury, no significant differences were found. The presence of an auditory distraction differentially affected the MTBI group for task 2 accuracy upon initial testing and at 30 days postinjury only.

CONCLUSIONS

The MTBI group performed both tasks significantly slower and less accurately than the control group upon initial testing and at 30 days postinjury. The presence of pop music further influenced accuracy of complex processing. At 60 days postinjury, accuracy of simple processing returned to preinjury levels and the auditory distraction no longer differentially influenced the MTBI group. All performance differences were resolved at 6 months postinjury.

Differential behavioral and histopathological responses to graded cortical impact injury in mice

Controlled cortical impact (CCI) injury, a model of contusive brain injury in humans, is being used with increasing frequency in mice to investigate post-traumatic cell damage and death and to evaluate treatment strategies. Because cellular injury mechanisms and therapeutic approaches may depend on the severity of the initial insult, it is important to utilize a model in which outcomes are sensitive to injury severity. Adult male C57Bl/6 mice were anesthetized and subjected to sham injury (n = 23) or CCI injury at either 0.5 mm (n = 22) or 1.0 mm (n = 22) depth of impact at a velocity of 5 m/sec. At 2 days, brain-injured mice exhibited significant memory (p < 0.05) and motor function (p < 0.001) deficits compared to sham-injured mice; furthermore, mice subjected to an impact of 1.0 mm were significantly more impaired in both outcome measures than those injured at 0.5 mm (p < 0.05). The cortical lesion increased in size between 24 h and 7 days in both injury groups, but was significantly larger in the 1.0 mm group. Hippocampal cell loss was observed in the hilar and CA3 regions in both groups, and in the CA1 and dentate granule cell layers in the 1.0 mm group. Regional patterns of IgG extravasation and reactive astrocytosis were similar in the two injured groups, but changes were more persistent in the 1.0 mm group. Both levels of injury resulted in acute loss of neuronal MAP-2 immunoreactivity in the cortex and sub-region specific changes in the hippocampus. Thus, increasing the depth of impact led to similar structural alterations in neurons, astrocytes and the vasculature, but resulted in greater behavioral deficits and cortical and hippocampal cell death.

The neurophysiology of brain injury

OBJECTIVE

This article reviews the mechanisms and pathophysiology of traumatic brain injury (TBI).

METHODS

Research on the pathophysiology of diffuse and focal TBI is reviewed with an emphasis on damage that occurs at the cellular level. The mechanisms of injury are discussed in detail including the factors and time course associated with mild to severe diffuse injury as well as the pathophysiology of focal injuries. Examples of electrophysiologic procedures consistent with recent theory and research evidence are presented.

RESULTS

Acceleration/deceleration (A/D) forces rarely cause shearing of nervous tissue, but instead, initiate a pathophysiologic process with a well defined temporal progression. The injury foci are considered to be diffuse trauma to white matter with damage occurring at the superficial layers of the brain, and extending inward as A/D forces increase. Focal injuries result in primary injuries to neurons and the surrounding cerebrovasculature, with secondary damage occurring due to ischemia and a cytotoxic cascade. A subset of electrophysiologic procedures consistent with current TBI research is briefly reviewed.

CONCLUSIONS

The pathophysiology of TBI occurs over time, in a pattern consistent with the physics of injury. The development of electrophysiologic procedures designed to detect specific patterns of change related to TBI may be of most use to the neurophysiologist.

SIGNIFICANCE

This article provides an up-to-date review of the mechanisms and pathophysiology of TBI and attempts to address misconceptions in the existing literature.

Contemporary issues in mild traumatic brain injury11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated

OBJECTIVES

To determine (1) minimum criteria in adults for clinical diagnosis of mild traumatic brain injury (TBI) and (2) whether persistent postconcussive syndrome exists as a nosologic entity.

DATA SOURCES

PubMed search by MEDLINE of head injuries from January 1977 to July 2002.

STUDY SELECTION

All reviews and studies of mild TBI with special reference to those on persistent postconcussive syndrome having a general trauma cohort as a control comparison.

DATA EXTRACTION

Review of design and other methodologic issues. Studies dependent on superior strength of evidence (as defined by the American Academy of Neurology) concerning the biologic nature of persistent postconcussive syndrome.

DATA SYNTHESIS

A period of altered awareness with amnesia brought on by a direct craniofacial blow is the starting point in determining whether diffuse mild TBI has occurred. An amnestic scale is more helpful than Glasgow Coma Scale score in grading mild injury and in formulating minimum inclusion criteria for mild TBI. Neuropsychologic test results coupled with self-reported symptoms should not be taken as the primary source of evidence for mild TBI. Prolonged cognitive impairment after injury is not unique to brain trauma.

CONCLUSIONS

Persistent postconcussive syndrome after mild brain trauma, uncomplicated by focal injury, is biologically inseparable from other examples of the posttraumatic syndrome. To account for the persistent cognitive and behavioral sequelae of posttraumatic states, including persistent postconcussive syndrome, we need further studies on the emerging concept of limbic neuronal attrition occurring as a maladaptive response to pain and stress.

Brain Imaging as a Predictor of Early Functional Outcome Following Traumatic Brain Injury in Children, Adolescents, and Young Adults

OBJECTIVES

A depth of lesion (DOL) model using brain imaging has been proposed to aid in medical decision-making and planning for rehabilitation resource needs. The purpose of this study was to determine the early prognostic value of a DOL classification system for children and young adults following severe traumatic brain injury.

METHODS AND OUTCOME MEASURES

CT/MRI brain imaging studies on 92 patients, aged 3 to 21, admitted to the Kluge Children's Rehabilitation Center, University of Virginia, were evaluated to determine DOL. Images were classified according to 5 DOL levels (cortical to brainstem). Functional outcomes in mobility, self-care, and cognition, as rated on the WeeFIM instrument, were compared by DOL levels.

RESULTS

Admission WeeFIM scores were significantly different for the DOL levels with the highest score for frontal and/or temporal lesions and the lowest for lesions including the brainstem or cerebellum (P<.001). However, the deeper the lesion, the greater the functional gains (P=.05), resulting in discharge WeeFIM scores that were not significantly different across DOL levels. Patients with deeper lesions tended to have longer lengths of stay in rehabilitation but were able to "catch up" with patients who had more superficial lesions.

CONCLUSIONS

While relatively simple and convenient, the DOL classification system is limited in its usefulness as an early prognostic tool. It may not be possible to predict outcome in the early acute phase in the intensive care unit on the basis of standard brain imaging alone. Patients with deeper lesions may enter rehabilitation at a more impaired level but can make remarkable progress, though it may take longer than for less severely injured individuals.

Can within-category naming identify subtle cognitive deficits in the mild traumatic brain-injured patient?

BACKGROUND

This investigation examined the effect of a speeded, computer-controlled task on detecting differences in latency and accuracy of within-category name generation in adults having sustained a mild traumatic brain injury (MTBI).

METHODS

Twenty-four adults in acute recovery and 24 age-matched controls were instructed to view 72 pictures on a computer monitor, and then name another item belonging to the same category as the visual stimulus as quickly as possible.

RESULTS

The MTBI group demonstrated significantly longer latencies (p < 0.001) and lower accuracy (p < 0.001) than the control group. Both groups displayed similar patterns of response, although the MTBI group produced significantly more perseverative errors (p < 0.001). No significant correlations were found between performance on the Scales of Cognitive Ability for Traumatic Brain Injury and response latency or accuracy.

CONCLUSION

The MTBI group performed the task significantly slower and less accurately than controls. Reaction time measures may prove more sensitive than traditional assessment measures in detecting subtle difficulties.

The neurophysiology of concussion

Cerebral concussion is both the most common and most puzzling type of traumatic brain injury (TBI). It is normally produced by acceleration (or deceleration) of the head and is characterized by a sudden brief impairment of consciousness, paralysis of reflex activity and loss of memory. It has long been acknowledged that one of the most worthwhile techniques for studying the acute pathophysiology of concussion is by the recording of neurophysiological activity such as the electroencephalogram (EEG) and sensory evoked potentials (EPs) from experimental animals. In the first parts of this review, the majority of such studies conducted during the past half century are critically reviewed. When potential methodological flaws and limitations such as anesthetic protocols, infliction of multiple blows and delay in onset of recordings were taken into account, two general principles could be adduced. First, the immediate post-concussive EEG was excitatory or epileptiform in nature. Second, the cortical EP waveform was totally lost during this period. In the second parts of this review, five theories of concussion which have been prominent during the past century are summarized and supportive evidence assessed. These are the vascular, reticular, centripetal, pontine cholinergic and convulsive hypotheses. It is concluded that only the convulsive theory is readily compatible with the neurophysiological data and can provide a totally viable explanation for concussion. The chief tenet of the convulsive theory is that since the symptoms of concussion bear a strong resemblance to those of a generalized epileptic seizure, then it is a reasonable assumption that similar pathobiological processes underlie them both. Further, it is demonstrated that EPs and EEGs recorded acutely following concussive trauma are indeed the same or similar to those obtained following the induction of a state of generalized seizure activity (GSA). According to the present incarnation of the convulsive theory, the energy imparted to the brain by the sudden mechanical loading of the head may generate turbulent rotatory and other movements of the cerebral hemispheres and so increase the chances of a tissue-deforming collision or impact between the cortex and the boney walls of the skull. In this conception, loss of consciousness is not orchestrated by disruption or interference with the function of the brainstem reticular activating system. Rather, it is due to functional deafferentation of the cortex as a consequence of diffuse mechanically-induced depolarization and synchronized discharge of cortical neurons. A convulsive theory can also explain traumatic amnesia, autonomic disturbances and the miscellaneous collection of symptoms of the post-concussion syndrome more adequately than any of its rivals. In addition, the symptoms of minor concussion (a.k.a. being stunned, dinged, or dazed) are often strikingly similar to minor epilepsy such as petit mal. The relevance of the convulsive theory to a number of associated problems is also discussed. These include the relationship between concussion and more serious types of closed head injury, the utility of animal models of severe brain trauma, the etiology of the cognitive deficits which may linger long after a concussive injury, the use of concussive (captive bolt) techniques to stun farm animals prior to slaughter and the question of why some animals (such as the woodpecker) can tolerate massive accelerative forces without being knocked out.

Neurophysiological and behavioral concomitants of mild brain injury in collegiate athletes

OBJECTIVES

There is still limited understanding regarding the effect of mild brain injury (MBI) on normal functioning of the human brain with respect to motor control and coordination. To our knowledge, no research exists on how both the accuracy of force production and underlying neurophysiological concomitants are interactively affected by MBI. The aim of this study is to provide empirical evidence that there are at least transient functional changes in the brain associated with motor control and coordination in collegiate athletes suffering from MBI as reflected in alterations of force trajectory patterns and electroencephalogram (EEG) potentials both in time and frequency domains.

METHODS

Comparisons of the performance and concomitant EEG waveforms both in time and frequency domains of 6 collegiate athletes with MBI and 6 normal subjects in a series of isometric force production tasks were made. The traditional averaging techniques to obtain the slow-wave movement-related potentials (MRP) and Morlet wavelet transform to obtain EEG time-frequency (TF) profiles associated with task performance were used. Subjects performed isometric force production tasks when the level of nominal force was experimentally manipulated. EEG recordings from the frontal-central areas were analyzed with respect to the accuracy of force production during the ramp phase.

RESULTS

Behaviorally, the accuracy of force trajectory performance was considerably impaired in MBI subjects even when the amount of task force was only increased from 25 to 50% maximum voluntary contraction (MVC) within a given subject. Electro-cortically, impaired performance in MBI subjects was associated with alterations in EEG waveforms, amplitude of MRP and TF profiles of EEG.

CONCLUSIONS

Both behavioral and electro-cortical data of control subjects generally were comparable with those from subjects with MBI when small amounts of force were regulated. However, differences become apparent as the amount of task force production was increased. Overall our findings identify the presence of transient functional changes in the brain associated with motor control and coordination in subjects suffering from MBI.

Neuropsychological outcome in relation to the traumatic coma data bank classification of computed tomography imaging

The Traumatic Coma Data Bank (TCDB) classification of CT (computed tomography) scan has been related to the general outcome and intracranial pressure evolution. Our aim was to analyse the relationship of this classification with neuropsychological outcome and late indices of ventricular dilatation. Fifty-seven patients with a moderate or severe head injury (mean admission Glasgow Coma Scale Score, 7.7) were studied from 122 consecutive cases. There were 49 males and 8 females (mean age, 27.7 years). Subjects were classified into TCDB categories on the basis of their most serious acute CT scan finding. From the last control CT scan image, performed at a mean of 6.12 months postinjury, several measures of ventricular dilatation were calculated. Neuropsychological assessment at 6-month included tests of verbal and visual memory, visuoconstructive functions, fine motor speed, and frontal lobe functions. Patients with diffuse injury type I showed better neuropsychological outcome than patients with more severe diffuse injuries and those with mass lesions. Within the diffuse injury groups, the degree of diffuse damage was related to measures of verbal memory and attention and cognitive flexibility. Ventricular enlargement was more evident in patients with mass lesions and it decreased in the remaining groups as the severity of diffuse injury diminished. These results show that there is a relationship between acute intracranial lesion diagnosis according to TCDB classification and neuropsychological results and ventricular dilatation indices at 6 months postinjury.

Imaging of head trauma in infancy and childhood

Neurologic trauma is one of the most common and challenging problems encountered in the pediatric emergency setting. Early and accurate diagnosis is essential to minimize morbidity and mortality. The primary goal of the neuroimager in the acute setting is to provide rapid diagnosis, to monitor the development of complications, and to aid in the determination of prognosis. Unique features of the immature brain and skull influence the patterns and types of injuries observed. It is incumbent on the radiologist to understand these features as an aid to diagnosis. Further, the radiologist must be aware of the pathophysiology and appearance of nonaccidental trauma to ensure recognition of this devastating problem. Lastly, the radiologic tools available, their appropriate use, and their limitations should be understood by the entire trauma team to provide cost-effective and timely care. This article summarizes the pathophysiology and current imaging of neurotrauma in the pediatric population, including trauma, nonaccidental trauma, accidental anoxic injury, and birth injury.

Depth of lesion model in children and adolescents with moderate to severe traumatic brain injury: use of SPGR MRI to predict severity and outcome

OBJECTIVES

The utility of a depth of lesion classification using an SPGR MRI sequence in children with moderate to severe traumatic brain injury (TBI) was examined. Clinical and depth of lesion classification measures of TBI severity were used to predict neurological and functional outcome after TBI.

METHODS

One hundred and six children, aged 4 to 19, with moderate to severe TBI admitted to a rehabilitation unit had an SPGR MRI sequence obtained 3 months afterTBI. Acquired images were analyzed for location, number, and size of lesions. The Glasgow coma scale (GCS) was the clinical indicator of severity. The deepest lesion present was used for depth of lesion classification. Speed of injury was inferred from the type of injury. The disability rating scale at the time of discharge from the rehabilitation unit (DRS1) and at 1 year follow up (DRS2) were functional outcome measures.

RESULTS

The depth of lesion classification was significantly correlated with GCS severity, number of lesions, and both functional measures, DRS1 and DRS2. This result was more robust for time 1, probably due to the greater number of psychosocial factors impacting on functioning at time 2. Lesion volume was not correlated with the depth of lesion model. In multivariate models, depth of lesion was most predictive of DRS1, whereas GCS was most predictive of DRS2.

CONCLUSIONS

A depth of lesion classification of TBI severity may have clinical utility in predicting functional outcome in children and adolescents with moderate to severe TBI.

Post-traumatic amnesia after closed head injury: a review of the literature and some suggestions for further research

Post-traumatic amnesia (PTA) is a transient sequela of closed head injury (CHI). The term PTA has been in clinical use for over half a century, and generally refers to the subacute phase of recovery immediately after unconsciousness following CHI. The duration of PTA predicts functional outcome after CHI, but its pathophysiological mechanism is not known. This paper compares current methods of determining the duration of PTA, summarizes reports on neuropsychological deficits in PTA, reviews available data that allow inferences about its mechanism, and suggests methods for further exploration of its pathophysiology.

Traumatic brain damage: serum S-100 protein measurements related to neuroradiological findings

This study was designed to investigate the correlation between S-100 protein serum measurements and neuroradiological findings in patients with head injury. We studied 278 patients with minor, moderate, and severe head injuries and 110 controls with no history of neurological disease. The study recruited patients from three Scandinavian neurotrauma centers. Serum levels of S-100 protein were measured at admittance, and computed tomographic scans of the brain were obtained within 24 h postinjury in all patients. In a subgroup of 45 patients with minor head injuries, magnetic resonance imaging was also performed. Increased serum level of S-100 protein was detected in 108 (39%) patients, and CT scan demonstrated intracranial pathology in 25 (9%) (brain contusion n = 13, subdural hematoma n = 6, epidural hematoma n = 2, traumatic subarachnoid hemorrhage n = 2, and brain edema n = 2). The proportion of patients with detectable serum level was significantly (p < 0.01) higher among those with intracranial pathology (92%) compared to those without (34%). The negative predictive value of an undetectable S-100 serum level was 0.99. Undetectable serum level of S-100 protein predicts normal intracranial findings on CT scan. Determination of S-100 protein in serum may be used to select patients for CT scanning.

Magnetic resonance imaging with gadolinium DTPA enhancement in patients with acute head injury

Gadolinium-enhanced magnetic resonance (MR) imaging in patients with acute head injury was conducted to study if contrast extravasation was associated with development of hemorrhagic lesions. A series of 60 head-injured patients were admitted to our emergency unit. Computerized tomography (CT) scans and skull x-ray films were taken as rapidly as possible after hospitalization. Injury severity on admission was evaluated using the Glasgow Coma Scale (GCS) score, motor score, and pupillary examination, while overall outcome was assessed with the Glasgow Outcome Scale (GOS) 3 months after injury. Of all patients admitted, MR imaging with gadolinium enhancement was performed in 18 patients who were at high risk of developing hemorrhagic lesion within 6 h after injury. In these patients we investigated whether contrast extravasation was associated with development of hemorrhagic lesions. All 18 patients presented abnormal findings on their admission CT scans. Admission GCS score in those patients who underwent MR imaging with gadolinium enhancement was 13 or more in 12 patients, 9-12 in four patients, and 8 or less in two patients. Fourteen of 18 patients showed contrast extravasation, corresponding with an evolution of lesion size. Nine of 14 patients who demonstrated extravasation of the contrast medium required surgical treatment. The results of the current study suggest that extravasation of contrast medium indicates a continuance of posttraumatic bleeding. Thus, MR imaging with gadolinium enhancement in acutely head-injured patients may constitute a reasonable strategy for predicting the development of hemorrhagic lesions.