Boomerang Sign on MRI

Introduction

Altered mental status and more subtle cognitive and personality changes after traumatic brain injury (TBI) are pervasive problems in patients who survive initial injury. MRI is not necessarily part of the diagnostic evaluation of these patients.

Methods

Case report with relevant image and review of the literature.

Results

Injury to the corpus callosum is commonly described in traumatic brain injury; however, extensive lesions in the splenium are not well described. This image shows an important pattern of brain injury and demonstrates a common clinical syndrome seen in patients with corpus callosum pathology.

Conclusion

Injury to the splenium of the corpus callosum due to trauma may be extensive and can cause significant neurologic deficits. MRI is important in the diagnostic evaluation of patients with cognitive changes after TBI.     

Revisiting Grade 3 Diffuse Axonal Injury: Not All Brainstem Microbleeds are Prognostically Equal

Background

Recovery of functional independence is possible in patients with brainstem traumatic axonal injury (TAI), also referred to as “grade 3 diffuse axonal injury,” but acute prognostic biomarkers are lacking. We hypothesized that the extent of dorsal brainstem TAI measured by burden of traumatic microbleeds (TMBs) correlates with 1-year functional outcome more strongly than does ventral brainstem, corpus callosal, or global brain TMB burden. Further, we hypothesized that TMBs within brainstem nuclei of the ascending arousal network (AAN) correlate with 1-year outcome.

Methods

Using a prospective outcome database of patients treated for moderate-to-severe traumatic brain injury at an inpatient rehabilitation hospital, we retrospectively identified 39 patients who underwent acute gradient-recalled echo (GRE) magnetic resonance imaging (MRI). TMBs were counted on the acute GRE scans globally and in the dorsal brainstem, ventral brainstem, and corpus callosum. TMBs were also mapped onto an atlas of AAN nuclei. The primary outcome was the disability rating scale (DRS) score at 1 year post-injury. Associations between regional TMBs, AAN TMB volume, and 1-year DRS score were assessed by calculating Spearman rank correlation coefficients.

Results

Mean ± SD number of TMBs was: dorsal brainstem = 0.7 ± 1.4, ventral brainstem = 0.2 ± 0.6, corpus callosum = 1.8 ± 2.8, and global = 14.4 ± 12.5. The mean ± SD TMB volume within AAN nuclei was 6.1 ± 18.7 mm³. Increased dorsal brainstem TMBs and larger AAN TMB volume correlated with worse 1-year outcomes (R = 0.37, p = 0.02, and R = 0.36, p = 0.02, respectively). Global, callosal, and ventral brainstem TMBs did not correlate with outcomes.

Conclusions

These findings suggest that dorsal brainstem TAI, especially involving AAN nuclei, may have greater prognostic utility than the total number of lesions in the brain or brainstem.

     

Differential vulnerability of white matter structures to experimental infantile hydrocephalus detected by diffusion tensor imaging

Purpose

The differential vulnerability of white matter (WM) to acute and chronic infantile hydrocephalus and the related effects of early and late reservoir treatment are unknown, but diffusion tensor imaging (DTI) could provide this information. Thus, we characterized WM integrity using DTI in a clinically relevant model.

Methods

Obstructive hydrocephalus was induced in 2-week-old felines by intracisternal kaolin injection. Ventricular reservoirs were placed 1 (early) or 2 (late) weeks post-kaolin and tapped frequently based solely on neurological deficit. Hydrocephalic and age-matched control animals were sacrificed 12 weeks postreservoir. WM integrity was evaluated in the optic system, corpus callosum, and internal capsule prereservoir and every 3 weeks using DTI. Analyses were grouped as acute (<6 weeks) or chronic (≥6 weeks).

Results

In the corpus callosum during acute stages, fractional anisotropy (FA) decreased significantly with early and late reservoir placement (p?=?0.0008 and 0.0008, respectively), and diffusivity increased significantly in early (axial, radial, and mean diffusivity, p?=?0.0026, 0.0012, and 0.0002, respectively) and late (radial and mean diffusivity, p?=?0.01 and 0.0038, respectively) groups. Chronically, the corpus callosum was thinned and not detectable by DTI. FA was significantly lower in the optic chiasm and tracts (p?=?0.0496 and 0.0052, respectively) with late but not early reservoir placement. In the internal capsule, FA in both reservoir groups increased significantly with age (p?Conclusions All hydrocephalic animals treated with intermittent ventricular reservoir tapping demonstrated progressive ventriculomegaly. Both reservoir groups demonstrated WM integrity loss, with the CC the most vulnerable and the optic system the most resilient.     

Tract-based spatial statistics of diffusion tensor imaging after corpus callosotomy in relation to seizure recurrence

Purpose

To delineate microstructural changes in transected white matter tracts after corpus callosotomy in relation to seizure recurrence using tract-based spatial statistics of diffusion tensor imaging (DTI-TBSS).

Methods

We retrospectively included 12 total corpus callosotomy patients who had undergone serial pre- and postoperative DTI studies. The first postoperative DTI was performed within 6 months after callosotomy. The second postoperative DTI was performed in five patients with seizure recurrence (symptomatic group) and in seven patients without seizure recurrence (asymptomatic group) after 1 year following surgery. Group comparisons of fractional anisotropy (FA) with age- and sex-matched controls were performed in a whole brain voxel-wise manner using DTI-TBSS.

Results

The first postoperative DTI-TBSS showed a significant FA decrease in the entire corpus callosum in all patients. The second postoperative DTI-TBSS showed that a significant FA decrease remained in the entire corpus callosum in the asymptomatic group. However, in the symptomatic group, no significant decrease of FA was observed in some parts of the posterior body and splenium of the corpus callosum, although there was still a significant FA decrease in the genu of the corpus callosum.

Conclusions

Using DTI-TBSS analysis, we characterized and visualized microstructural white matter changes over time in relation to seizure recurrence in callosotomy patients, suggesting that reorganization of some transected white matter tracts may be related to seizure recurrence. DTI-TBSS analysis can provide reliable and useful information about the state of white matter bundles affected by corpus callosotomy in a noninvasive manner.     

Camellia sinensis neuroprotective role in experimentally induced hydrocephalus in Wistar rats

Purpose

This study tested possible neuroprotective effects of Camellia sinensis-extracted polyphenols in experimental hydrocephalus in young rats.

Methods

Seven-day-old Wistar rats were used in this study. Pups were subjected to hydrocephalus induction by 20 % kaolin intracisternal injection. The polyphenol was administered intraperitoneally for 9 or 20 days from the induction of hydrocephalus. Clinical observations and behavioral tests were performed once a day. The animals, deeply anesthetized, were sacrificed by cardiac perfusion with saline 10 or 21 days after induction of hydrocephalus and their brains were removed. Preparations were made for histological analysis by hematoxylin and eosin, solochrome-cyanine, and immunohistochemistry for GFAP.

Results

Histopathological analysis showed that animals treated with the polyphenol for 9 consecutive days displayed reduction on astrocyte activity on the corpus callosum and external capsule, shown by GFAP immunostaining. They also displayed thicker and myelinated corpus callosum, exhibiting a more intense solochrome-cyanine blue staining.

Conclusion

Although these results demonstrate a possible neuroprotective effect at the initial onset of the disease, additional studies should be performed to obtain an effective and safe therapy for deeper studies in clinical trials.     

Regional Brain Injury on Conventional and Diffusion Weighted MRI is Associated with Outcome After Pediatric Cardiac Arrest

Background

To assess regional brain injury on magnetic resonance imaging (MRI) after pediatric cardiac arrest (CA) and to associate regional injury with patient outcome and effects of hypothermia therapy for neuroprotection.

Methods

We performed a retrospective chart review with prospective imaging analysis. Children between 1 week and 17 years of age who had a brain MRI in the first 2 weeks after CA without other acute brain injury between 2002 and 2008 were included. Brain MRI (1.5 T General Electric, Milwaukee, WI, USA) images were analyzed by 2 blinded neuroradiologists with adjudication; images were visually graded. Brain lobes, basal ganglia, thalamus, brain stem, and cerebellum were analyzed using T1, T2, and diffusion-weighted images (DWI).

Results

We examined 28 subjects with median age 1.9 years (IQR 0.4–13.0) and 19 (68 %) males. Increased intensity on T2 in the basal ganglia and restricted diffusion in the brain lobes were associated with unfavorable outcome (all P < 0.05). Therapeutic hypothermia had no effect on regional brain injury. Repeat brain MRI was infrequently performed but demonstrated evolution of lesions.

Conclusion

Children with lesions in the basal ganglia on conventional MRI and brain lobes on DWI within the first 2 weeks after CA represent a group with increased risk of poor outcome. These findings may be important for developing neuroprotective strategies based on regional brain injury and for evaluating response to therapy in interventional clinical trials.     

Site- and stage-dependent differences in vascular density of the human fetal brain

Background and purpose

Less information is available about site-dependent differences in fetal intrabrain angiogenesis. Quantitative evaluation is especially limited, with the measured area limited to the cerebral gray and white matters and the periventricular germinal matrix.

Patients and methods

We measured vascular density (number of vessels per square millimeter) and percent vascular area (percentage of areas occupied by vessels) of CD34-positive microvessels in 14 human fetal brains, including 4 fetuses at 14–16 weeks of gestation, 5 at 25–28 weeks, and 5 at 35–37 weeks. Site-dependent differences were examined among the cerebral cortex, thalamus, internal capsule, corpus callosum, ganglionic eminence, midbrain, and cerebellar cortex and nuclei.

Results

The parameters examined tended to be high in the cerebral germinal matrix, thalamus, midbrain, and cerebellum. Significant site-dependent differences were observed: lower vascular densities were observed in the internal capsule and corpus callosum than in other parts of the brain (p?<?0.05) and a larger percent area was observed in the cerebellar nuclei than in other areas. Vascular density was higher during the early than late stage because of the larger numbers of CD34-positive islands of cells in the early stage, although there were several exceptions. Percent area was not stage dependent but was almost constant at many sites.

Conclusion

Consequently, except for developing nuclei, the prenatal development of intrabrain vessels after 15 weeks may proceed without any significant changes in density.     

Longitudinal Diffusion Tensor Imaging Detects Recovery of Fractional Anisotropy Within Traumatic Axonal Injury Lesions

Background

Traumatic axonal injury (TAI) may be reversible, yet there are currently no clinical imaging tools to detect axonal recovery in patients with traumatic brain injury (TBI). We used diffusion tensor imaging (DTI) to characterize serial changes in fractional anisotropy (FA) within TAI lesions of the corpus callosum (CC). We hypothesized that recovery of FA within a TAI lesion correlates with better functional outcome.

Methods

Patients who underwent both an acute DTI scan (≤day 7) and a subacute DTI scan (day 14 to inpatient rehabilitation discharge) at a single institution were retrospectively analyzed. TAI lesions were manually traced on the acute diffusion-weighted images. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial diffusivity (AD), and radial diffusivity (RD) were measured within the TAI lesions at each time point. FA recovery was defined by a longitudinal increase in CC FA that exceeded the coefficient of variation for FA based on values from healthy controls. Acute FA, ADC, AD, and RD were compared in lesions with and without FA recovery, and correlations were tested between lesional FA recovery and functional recovery, as determined by disability rating scale score at discharge from inpatient rehabilitation.

Results

Eleven TAI lesions were identified in 7 patients. DTI detected FA recovery within 2 of 11 TAI lesions. Acute FA, ADC, AD, and RD did not differ between lesions with and without FA recovery. Lesional FA recovery did not correlate with disability rating scale scores.

Conclusions

In this retrospective longitudinal study, we provide initial evidence that FA can recover within TAI lesions. However, FA recovery did not correlate with improved functional outcomes. Prospective histopathological and clinical studies are needed to further elucidate whether lesional FA recovery indicates axonal healing and has prognostic significance.

     

Circulating proteasome activity following mild head injury in children

Purpose

The aim of the study is to characterize changes in circulating proteasome (c-proteasome) activity following mild traumatic brain injury in children.

Methods

Fifty children managed at the Department of Pediatric Surgery because of concussion—mild head injury was randomly included into the study. The children were aged 11 months to 17 years (median?=?10.07?+??1.91 years). Plasma proteasome activity was assessed using Suc-Leu-Leu-Val-Tyr-AMC peptide substrate, 2–6 h, 12–16 h, and 2 days after injury. Twenty healthy children admitted for planned inguinal hernia repair served as controls.

Results

Statistically significant elevation of plasma c-proteasome activity was noted in children with mild head injury 2–6 h, 12–16 h, and 2 days after the injury.

Conclusions

Authors observed a statistically significant upward trend in the c-proteasome activity between 2–6 and 12–16 h after the mild head injury, consistent with the onset of the symptoms of cerebral concussion and a downward trend in the c-proteasome activity in the plasma of children with mild head injury between 12–16 h and on the second day after the injury, consistent with the resolving of the symptoms of cerebral concussion. Further studies are needed to demonstrate that the proteasome activity could be a prognostic factor, which can help in further diagnostic and therapeutic decisions in patients with head injury.     

A retrospective comparison of CT and MRI in detecting pediatric cervical spine injury

Purpose

Although clinical criteria have been applied in the assessment of pediatric cervical spine trauma, no consensus has been established when imaging is required. With the increasing prevalence of computed tomography (CT) use in pediatric trauma and the concern for radiation in children, we sought to evaluate magnetic resonance imaging (MRI) and CT in detecting pediatric cervical spine injuries.

Methods

We retrospectively queried a pediatric trauma database and identified pediatric patients who underwent both CT and MRI studies of the cervical spine and derived the statistical measures of each imaging modality to detect osseous and ligamentous/soft tissue injury.

Results

Eighty-four patients were identified with a mean age of 9.0?±?5.8 years (56 % male). Sixteen patients were identified with injury, 12 with soft tissue abnormalities on MRI (nine edema and six ligamentous), and 6 with osseous abnormalities on CTs (six osseous fractures and one discogenic injury). Of the six patients who presented with CT-identified osseous injuries, MRI detected all six fractures as well as an additional compression fracture.

Conclusion

Using CT as the standard for osseous injury, MRI had a sensitivity of 100 %, specificity of 97 %, negative predictive value (NPV) of 75 %, and positive predictive value (PPV) of 100 %. Using MRI as the standard for soft tissue injury, CT had a sensitivity of 23 %, specificity of 100 %, NPV of 88 %, and PPV of 100 %. Further studies are required to investigate the use of MRI to detect osseous injuries.     

Intracranial Pressure Dose and Outcome in Traumatic Brain Injury

Objective

Detecting and treating elevated intracranial pressure (ICP) is a cornerstone of management in patients with severe traumatic brain injury. The aim of this study was to determine the association between area under the curve measurement of elevated ICP and clinical outcome.

Methods

Single center observational study using prospectively collected data at a University hospital, level one-trauma center. Sixty prospective patients with severe traumatic brain injury were prospectively enrolled over a 2-year period. Intracranial pressure measurements were captured using a real-time automated, high resolution vital signs data recording system. Mortality and functional outcome were assessed at 30 days, 3 and 6 months using Extended Glasgow Outcome Scale.

Results

Increasing elevated intracranial pressure time dose was associated with mortality (OR 1.08; 95 % confidence interval [CI], 1.01–1.15, p = 0.03) and poor functional outcome at 3 (OR 1.04; CI 1.00–1.07, p = 0.03) and 6 months (1.04; CI 1.01–1.08, p = 0.02). However, there was no association between episodic ICP data and outcome.

Conclusions

These results suggest that pressure time dose measurement of intracranial pressure may be used to predict outcome in severe traumatic brain injury and may be a candidate biomarker in this disease.     

Comparison of ultrasound and magnetic resonance imaging in the prenatal diagnosis of Apert syndrome: report of a case

Background

The birth prevalence of Apert syndrome is estimated at 1:64,500 and accounts for about 4.5 % of all craniosynostosis with a male/female ratio equal to 1:1. It is associated to allelic mutations in the fibroblast growth factor receptor 2 (FGFR2) gene. Majority cases are sporadic. Prenatal ultrasound diagnosis is based on the detection of abnormal cranial shape, midfacial hypoplasia and bilateral syndactyly of hands and feet, hypertelorism, and exorbitism. Other abnormalities includes central nervous system anomalies, congenital heart diseases, cleft palate, and urogenital diseases.

Case report

A 37-year-old Caucasian woman, gravida 2, para 1, was referred to our center of Prenatal Diagnosis for routine ultrasound at 21 weeks of gestation. We detected irregular head shape, dolicocephaly, prominent forehead, bilateral mild ventriculomegaly, suspicion of partial agenesis of the corpus callosum, hypertelorism, and midfacial hypoplasia, with a depressed nasal bridge and syndactyly, prompting a suspicion for Apert syndrome. Magnetic resonance excluded agenesis of corpus callosum and confirmed bilateral mild ventriculomegaly. A follow-up ultrasound, performed at 23 weeks, confirmed the anomalies showed in the previous scan. An amniocentesis was performed. The results showed a normal male karyotype, while the molecular genetic test confirmed a mutation in FGFR2 gene. Fetus macroscopic analysis showed compatible features.

Conclusions

Our case underlines the complementary role of ultrasound and magnetic resonance imaging in the early prenatal diagnosis of Apert syndrome.     

Evidence for white matter disruption in traumatic brain injury without macroscopic lesions

Background

Non‐missile traumatic brain injury (nmTBI) without macroscopically detectable lesions often results in cognitive impairments that negatively affect daily life.

Aim

To identify abnormal white matter projections in patients with nmTBI with cognitive impairments using diffusion tensor magnetic resonance imaging (DTI).

Methods

DTI scans of healthy controls were compared with those of 23 patients with nmTBI who manifested cognitive impairments but no obvious neuroradiological lesions. DTI was comprised of fractional anisotropy analysis, which included voxel‐based analysis and confirmatory study using regions of interest (ROI) techniques, and magnetic resonance tractography of the corpus callosum and fornix.

Results

A decline in fractional anisotropy around the genu, stem and splenium of the corpus callosum was shown by voxel‐based analysis. Fractional anisotropy values of the genu (0.47), stem (0.48), and splenium of the corpus callosum (0.52), and the column of the fornix (0.51) were lower in patients with nmTBI than in healthy controls (0.58, 0.61, 0.62 and 0.61, respectively) according to the confirmatory study of ROIs. The white matter architecture in the corpus callosum and fornix of patients with nmTBI were seen to be coarser than in the controls in the individual magnetic resonance tractography.

Conclusions

Disruption of the corpus callosum and fornix in patients with nmTBI without macroscopically detectable lesions is shown. DTI is sensitive enough to detect abnormal neural fibres related to cognitive dysfunction after nmTBI.Cognitive and vocational sequelae are common complications after non‐missile traumatic brain injury (nmTBI) without obvious neuroradiological lesions.^1,2 They may present as memory disturbance, impairments in multitask execution and loss of self‐awareness.³ These symptoms have been attributed to diffuse brain injury and the diffuse loss of white matter or neural networks in the brain.^4,5,6 Currently no accurate method is available for diagnosing and assessing the distribution and severity of diffuse axonal injury. As computed tomography and magnetic resonance imaging (MRI) findings underestimate the extent of diffuse axonal injury and correlate poorly with the final neuropsychological outcome,^7,8 this dysfunction tends to be clinically underdiagnosed or overlooked. Indirect evidence for loss of functional connectivity after nmTBI has been provided by both morphometric and functional neuroimaging studies. Morphometric analysis of nmTBI has shown the relationship between atrophy of the corpus callosum and fornix and the neuropsychological outcome.⁹ Most functional neuroimaging studies conducted after nmTBI have shown that cognitive and behavioural disorders are correlated, with some degree of secondary hypometabolism or hypoperfusion in regions of the cortex.⁵ To date, however, there has been no direct in vivo demonstration of structural disconnections without macroscopically detectable lesions in patients with nmTBI.Diffusion tensor magnetic resonance imaging (DTI), which measures diffusion anisotropy in vivo, is a promising method for the non‐invasive detection of the degree of fibre damage in various disease processes affecting the white matter.^10,11 In biological systems, the diffusional motion of water is impeded by tissue structures, such as cell membranes, myelin sheaths, intracellular microtubules and associated proteins. Motion parallel to axons or myelin sheaths is inhibited to a lesser degree than perpendicular motion, a phenomenon known as diffusion anisotropy.¹² Fractional anisotropy was applied to evaluation of post‐traumatic diffuse axonal injury¹³ and its clinical usefulness described. In a previous study,¹⁴ fractional anisotropy score in the acute stage as an index of injury to white matter showed promise in predicting outcome in patients with traumatic brain injury, by using the regions of interest (ROIs) techniques. MRI voxel‐based analysis, a statistical normalising method, has been developed to reduce interindividual variability and to evaluate the whole brain objectively.^15,16,17 We investigated the regions in the whole brain that are commonly injured in patients having nmTBI with cognitive impairments but no macroscopic lesions, using voxel‐based analysis of fractional anisotropy, referred to as diffusion anisotropy. The advent of DTI has allowed inter‐regional fibre tracking, called magnetic resonance tractography, which reconstructs the three‐dimensional trajectories of white matter tracts.^11,18,19 We also investigated whether magnetic resonance tractography sensitively recognises degeneration of the corpus callosum and fornix in individual patients with nmTBI.     

Is therapeutic hypothermia beneficial for pediatric patients with traumatic brain injury? A meta-analysis

Purpose

Hypothermia therapy shows its unique potential for reducing mortality in animal study and improving neurologic outcome in patients with traumatic brain injury. However, therapeutic hypothermia for pediatric traumatic brain injury remains a controversial issue. To determine the effectiveness and safety of hypothermia treatment for pediatric traumatic brain injury patients, we conducted this meta-analysis.

Patients and methods

We analyzed the data from MEDLINE, Pubmed, EMBASE, and Cochrane Library by electronic searching. No limitation of language was selected for analysis. We extracted the mortality and adverse events from the published trials.

Results

Six clinical trials and 366 pediatric patients met our inclusion criteria. Pediatric patients with traumatic brain injury treated with hypothermia had more unfavorable outcome than those in the normothermia group (RR 1.73, 95 % CI 1.06 to 2.84), and this increased risk is statistically significant. Patients with therapeutic hypothermia are slightly likely to be induced by cardiac arrhythmia, and the likelihood is also significant (RR 2.57, 95 % CI 1.01 to 6.54). Risk of pneumonia has no statistical difference between normothermia and hypothermia arms (RR 0.90, 95 % CI 0.73 to 1.12). Two of the included trials have reported their detail randomization assignment.

Conclusions

Hypothermia may slightly increase the risk of mortality in children with traumatic brain injury and the ratio of cardiac arrhythmia after this hypothermia therapy is slightly higher than that in normothermia groups. In the future, more randomized controlled trials and multicenter studies on the mechanism of therapeutic hypothermia are required.     

Altered white matter microstructure identified with tract-based spatial statistics in irritable bowel syndrome: a diffusion tensor imaging study

The neural mechanisms underlying the pathophysiology of irritable bowel syndrome(IBS) are far from being completely understood. The purpose of the present study was to investigate potential white matter (WM) microstructural changes and underlying causes for WM impairment in IBS using diffusion tensor imaging. The present prospective study involved 19 patients with IBS and 20 healthy controls. Whole-brain voxel-wise analyses of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were performed by tract-based spatial statistics (TBSS) to localize abnormal WM regions between the 2 groups. We found that IBS patients had significantly reduced FA (P < 0.05) in the splenium of the corpus callosum, the right retrolenticular area of the internal capsule and the right superior corona radiata. We also found increased MD (P < 0.05) in the splenium and body of the corpus callosum, the right retrolenticular area of the internal capsule, the right superior corona radiata and the right posterior limb of the internal capsule. In addition, IBS patients had significantly increased AD (P < 0.05) in the splenium of the corpus callosum, the bilateral retrolenticular area of the internal capsule and the left posterior limb of the internal capsule. We conclude that the WM microstructure is changed in IBS and the underlying pathological basis may be attributed to the axonal injury and loss. These results may lead to a better understanding of the pathophysiology of IBS.     

Corpus callosum atrophy is associated with mental slowing and executive deficits in subjects with age-related white matter hyperintensities: the LADIS Study

Background

Previous research has indicated that corpus callosum atrophy is associated with global cognitive decline in neurodegenerative diseases, but few studies have investigated specific cognitive functions.

Objective

To investigate the role of regional corpus callosum atrophy in mental speed, attention and executive functions in subjects with age‐related white matter hyperintensities (WMH).

Methods

In the Leukoaraiosis and Disability Study, 567 subjects with age‐related WMH were examined with a detailed neuropsychological assessment and quantitative magnetic resonance imaging. The relationships of the total corpus callosum area and its subregions with cognitive performance were analysed using multiple linear regression, controlling for volume of WMH and other confounding factors.

Results

Atrophy of the total corpus callosum area was associated with poor performance in tests assessing speed of mental processing—namely, trail making A and Stroop test parts I and II. Anterior, but not posterior, corpus callosum atrophy was associated with deficits of attention and executive functions as reflected by the symbol digit modalities and digit cancellation tests, as well as by the subtraction scores in the trail making and Stroop tests. Furthermore, semantic verbal fluency was related to the total corpus callosum area and the isthmus subregion.

Conclusions

Corpus callosum atrophy seems to contribute to cognitive decline independently of age, education, coexisting WMH and stroke. Anterior corpus callosum atrophy is related to the frontal‐lobe‐mediated executive functions and attention, whereas overall corpus callosum atrophy is associated with the slowing of processing speed.Corpus callosum is the largest commissural structure consisting of white matter tracts that connect the cerebral hemispheres according to an anterior–posterior topographical organisation. Recent research using diffusion tensor magnetic resonance imaging (MRI) has augmented earlier postmortem findings of corpus callosum topography and has shown that the anterior parts of corpus callosum (rostrum and genu) connect the orbitofrontal, lateral and medial frontal cortices, whereas the body and splenium connect parietal, temporal and occipital homotopic regions.¹ In neurodegenerative diseases, the corpus callosum area is markedly reduced, indicating marked axonal loss.^2,3,4,5 In Alzheimer''s disease, the severity and pattern of corpus callosum atrophy have been associated with cortical neuronal loss⁶ independently of white matter hyperintensities (WMH).⁷ In vascular dementia and other ischaemic conditions, however, corpus callosum atrophy is correlated with WMH and hence may result from subcortical ischaemic damage.^8,9Earlier studies have shown that corpus callosum atrophy is associated with global cognitive status,^5,6,10 but, to date, few studies have investigated the role of regional corpus callosum atrophy in specific cognitive processes. Based on the topographical organisation of corpus callosum, the integrity of its subregions may reflect distinct cognitive deficits. In particular, anterior corpus callosum atrophy may be related to the frontal‐lobe‐mediated executive deficits. Previous work of the Leukoaraiosis and Disability (LADIS) Study has shown that age‐related WMH are associated with cognitive impairment in elderly subjects without dementia.¹¹ Moreover, in these subjects, the corpus callosum area has been found to be inversely related to motor deficits and global cognitive decline.¹² This study examined the independent contribution of regional corpus callosum atrophy to deficits in mental speed, attention and executive functions in a large sample of elderly subjects with WMH by using quantitative MRI analysis and targeted neuropsychological test methods. The demographic and medical background variables, and coexisting WMH were controlled by using multivariate analysis.     

Morris water maze function and histologic characterization of two age-at-injury experimental models of controlled cortical impact in the immature rat

Purpose

Controlled cortical impact (CCI) is commonly used in adult animals to study focal traumatic brain injury (TBI). Our study aims to further study injury mechanisms in children and variable models of pathology in the developing brain.

Methods

Develop a focal injury model of experimental TBI in the immature, postnatal days (PND) 7 and 17 rats that underwent a CCI at varying depths of deflection, 1.5–2.5 mm compared with sham and then tested using the Morris water maze (MWM) beginning on post-injury day (PID) 11. Histopathologic analysis was performed at PID 1 and 28.

Results

In PND 7, the 1.75- and 2.0-mm deflections (diameter (d)?=?3 mm; velocity?=?4 m/s; and duration?=?500 ms) resulted in significant MWM deficits while the 1.5-mm injury did not produce MWM deficits vs. sham controls. In PND 17, all injury levels resulted in significant MWM deficits vs. sham controls with a graded response; the 1.5-mm deflection (d?=?6 mm; velocity?=?4 m/s; and duration?=?500 ms) produced significantly less deficits as compared WITH the 2.0- and 2.5-mm injuries. Histologically, a graded injury response was also seen in both ages at injury with cortical and more severe injuries, hippocampal damage. Cortical contusion volume increased in most injury severities from PID 1 to 28 in both ages at injury while hippocampal volumes subsequently decreased.

Conclusions

CCI in PND 7 and 17 rat results in significant MWM deficits and cortical histopathology providing two different and unique experimental models of TBI in immature rats that may be useful in further investigations into the mechanisms and treatments of pediatric TBI.     

Neurologist Versus Machine: Is the Pupillometer Better than the Naked Eye in Detecting Pupillary Reactivity

Background

A 62-year-old man with severe traumatic brain injury developed postsurgical anisocoria in which there was a discrepancy between pupillometer and manual testing.

Methods

Case report.

Results

The patient’s larger pupil was read as unreactive by the pupillometer but constricted 1 mm over 7–9 s of continuous light stimulation.

Conclusions

While pupillometry assessment is a valuable adjunct to the manual pupillary assessment, this case demonstrates that nonreactive pupils read on the pupillometer should be confirmed with the manual examination because it can miss very slowly reacting pupils.     

Automated Quantitative Pupillometry for the Prognostication of Coma After Cardiac Arrest

Background

Sedation and therapeutic hypothermia (TH) delay neurological responses and might reduce the accuracy of clinical examination to predict outcome after cardiac arrest (CA). We examined the accuracy of quantitative pupillary light reactivity (PLR), using an automated infrared pupillometry, to predict outcome of post-CA coma in comparison to standard PLR, EEG, and somato-sensory evoked potentials (SSEP).

Methods

We prospectively studied over a 1-year period (June 2012–June 2013) 50 consecutive comatose CA patients treated with TH (33 °C, 24 h). Quantitative PLR (expressed as the % of pupillary response to a calibrated light stimulus) and standard PLR were measured at day 1 (TH and sedation; on average 16 h after CA) and day 2 (normothermia, off sedation: on average 46 h after CA). Neurological outcome was assessed at 90 days with Cerebral Performance Categories (CPC), dichotomized as good (CPC 1–2) versus poor (CPC 3–5). Predictive performance was analyzed using area under the ROC curves (AUC).

Results

Patients with good outcome [n = 23 (46 %)] had higher quantitative PLR than those with poor outcome [n = 27; 16 (range 9–23) vs. 10 (1–30) % at day 1, and 20 (13–39) vs. 11 (1–55) % at day 2, both p < 0.001]. Best cut-off for outcome prediction of quantitative PLR was <13 %. The AUC to predict poor outcome was higher for quantitative than for standard PLR at both time points (day 1, 0.79 vs. 0.56, p = 0.005; day 2, 0.81 vs. 0.64, p = 0.006). Prognostic accuracy of quantitative PLR was comparable to that of EEG and SSEP (0.81 vs. 0.80 and 0.73, respectively, both p > 0.20).

Conclusions

Quantitative PLR is more accurate than standard PLR in predicting outcome of post-anoxic coma, irrespective of temperature and sedation, and has comparable prognostic accuracy than EEG and SSEP.     

Palliative epilepsy surgery in Aicardi syndrome: a case series and review of literature

Purpose

Aicardi syndrome (AS) is a severe neurodevelopmental disorder characterized by the triad of seizures, agenesis of corpus callosum, and chorioretinal lacunae. Seizures in AS are typically frequent, of various types, and refractory to medical therapy. Optimal treatment of seizures in AS remains undetermined.

Methods

We report a series of four patients with Aicardi syndrome who underwent surgical management of their epilepsy including two with corpus callosotomy (CC) of a partial corpus callosum and three with vagus nerve stimulator implantation.

Results

Seizure outcome was variable and ranged from near complete resolution of seizures to worsening of seizure profile. The most favorable seizure outcome was seen in a patient with partial agenesis of the corpus callosum treated with CC.

Conclusions

Seizure outcome following CC or vagus nerve stimulation in patients with Aicardi syndrome is variable. Although palliative epilepsy surgery may result in improvement in the seizure profile in some patients, studies on larger patient cohorts are needed to identify the precise role that surgery may play in the multidisciplinary approach to controlling seizures in Aicardi syndrome.