Functional Outcome of Hemorrhagic Transformation after Thrombolysis for Ischemic Stroke: A Prospective Study

Background/Aims

Hemorrhagic transformation (HT) is usually taken into account when symptomatic, but the role of asymptomatic HT is not well known. The aim of our study was to evaluate the link between HT after thrombolysis for ischemic stroke and functional outcome at 3 months, with particular emphasis on asymptomatic HT.

Methods

Our study was performed prospectively between June 2012 and June 2013 in the Stroke Unit of the University Hospital Center of Tours (France). All patients treated with intravenous thrombolysis were consecutively included. HT was classified on susceptibility-weighted imaging (SWI) with 3-tesla MRI at 7 ± 3 days after treatment. We evaluated functional outcome at 3 months using the modified Rankin Scale (mRS). Dependency was defined as an mRS score of ≥3.

Results

After 1 year, 128 patients had received thrombolytic therapy for ischemic stroke, of whom 90 patients underwent both 3-tesla MRI and SWI at day 7. Fifty-two had HT, including 8 symptomatic cases. At 3 months, 68% of those patients were dependent compared to 31% of patients without HT [OR 4.6 (1.9-11.4), p = 0.001]. In asymptomatic HT, the rate was 62% [OR 3.5 (1.4-8.9), p = 0.007], but did not reach significance after adjustment for stroke severity.

Discussion

Our study found no statistically significant effect of HT on outcome after adjustment for initial stroke severity. However, the innocuousness of HT is not certain, and only few studies have already highlighted the increased risk of dependency. Using 3-tesla MRI with SWI allows us to increase the detection rate of small hemorrhage.

Conclusion

HT after thrombolysis is very frequent on SWI, but the initial stroke severity is an important predictor to assess the role of HT for patient outcome.

The Pattern of Brain Amyloid Load in Posterior Cortical Atrophy Using (18)F-AV45: Is Amyloid the Principal Actor in the Disease?

Background

Posterior cortical atrophy (PCA) is characterized by progressive higher-order visuoperceptual dysfunction and praxis declines. This syndrome is related to a number of underlying diseases, including, in most cases, Alzheimer's disease (AD). The aim of this study was to compare the amyloid load with ¹⁸F-AV45 positron emission tomography (PET) between PCA and AD subjects.

Methods

We performed ¹⁸F-AV45 PET, cerebrospinal fluid (CSF) biomarker analysis and a neuropsychological assessment in 11 PCA patients and 12 AD patients.

Results

The global and regional ¹⁸F-AV45 uptake was similar in the PCA and AD groups. No significant correlation was observed between global ¹⁸F-AV45 uptake and CSF biomarkers or between regional ¹⁸F-AV45 uptake and cognitive and affective symptoms.

Conclusion

This ¹⁸F-AV45 PET amyloid imaging study showed no specific regional pattern of cortical ¹⁸F-AV45 binding in PCA patients. These results confirm that a distinct clinical phenotype in amnestic AD and PCA is not related to amyloid distribution.

FIBRASCAN: a novel method for 3D white matter tract reconstruction in MR space from cadaveric dissection

INTRODUCTION

Diffusion tractography relies on complex mathematical models that provide anatomical information indirectly, and it needs to be validated. In humans, up to now, tractography has mainly been validated by qualitative comparison with data obtained from dissection. No quantitative comparison was possible because Magnetic Resonance Imaging (MRI) and dissection data are obtained in different reference spaces, and because fiber tracts are progressively destroyed by dissection. Here, we propose a novel method and software (FIBRASCAN) that allow accurate reconstruction of fiber tracts from dissection in MRI reference space.

METHOD

Five human hemispheres, obtained from four formalin-fixed brains were prepared for Klingler's dissection, placed on a holder with fiducial markers, MR scanned, and then dissected to expose the main association tracts. During dissection, we performed iterative acquisitions of the surface and texture of the specimens using a laser scanner and two digital cameras. Each texture was projected onto the corresponding surface and the resulting set of textured surfaces was coregistered thanks to the fiducial holders. The identified association tracts were then interactively segmented on each textured surface and reconstructed from the pile of surface segments. Finally, the reconstructed tracts were coregistered onto ex vivo MRI space thanks to the fiducials. Each critical step of the process was assessed to measure the precision of the method.

RESULTS

We reconstructed six fiber tracts (long, anterior and posterior segments of the superior longitudinal fasciculus; Inferior fronto-occipital, Inferior longitudinal and uncinate fasciculi) from cadaveric dissection and ported them into ex vivo MRI reference space. The overall accuracy of the method was of the order of 1mm: surface-to-surface registration=0.138mm (standard deviation (SD)=0.058mm), deformation of the specimen during dissection=0.356mm (SD=0.231mm), and coregistration surface-MRI=0.6mm (SD=0.274mm). The spatial resolution of the method (distance between two consecutive surface acquisitions) was 0.345mm (SD=0.115mm).

CONCLUSION

This paper presents the robustness of a novel method, FIBRASCAN, for accurate reconstruction of fiber tracts from dissection in the ex vivo MR reference space. This is a major step toward quantitative comparison of MR tractography with dissection results.

Could (18) F-DPA-714 PET imaging be interesting to use in the early post-stroke period?

Background

Cerebral stroke is a severe and frequent condition that requires rapid and reliable diagnosis. If administered shortly after the first symptoms manifest themselves, IV thrombolysis has been shown to increase the functional prognosis by restoring brain reperfusion. However, a better understanding of the pathophysiology of stroke should help to identify potential new therapeutic targets. Stroke is known to induce an inflammatory brain reaction that involves overexpression of the 18-kDa translocator protein (TSPO) in glial cells and infiltrated leukocytes, which can be visualised by positron emission tomography (PET). We aimed to evaluate post-stroke neuroinflammation using the PET TSPO radioligand ¹⁸ F-DPA-714.

Methods

Nine patients underwent ¹⁸ F-DPA-714 PET and magnetic resonance imaging (MRI) between 8 and 18 days after the ictus. Co-registration of MRI and PET images was used to define three volumes of interest (VOIs): core infarction, contralateral region, and cerebellum ipsilateral to the stroke lesion. Time activity curves were obtained from each VOI, and ratios of mean and maximum activities between the VOIs were calculated.

Results

We observed an increased uptake of ¹⁸ F-DPA-714 co-localised with the infarct tissue and extension beyond the region corresponding to the damage in the blood brain barrier. No correlation was identified between ¹⁸ F-DPA-714 uptake and infarct volume. ¹⁸ F-DPA-714 uptake in ischemic lesion (mainly associated with TSPO expression in the infarct area and in the surrounding neighbourhood) slowly decreased from 10 min pi to the end of the PET acquisition, remaining higher than that in both contralateral region and ipsilateral cerebellum.

Conclusion

Our results show that ¹⁸ F-DPA-714 uptake after acute ischemia is mainly associated with TSPO expression in the infarct area and in the surrounding neighbourhood. We also demonstrated that the kinetics of ¹⁸ F-DPA-714 differs in injured tissue compared to normal tissue. Therefore, ¹⁸ F-DPA-714 may be useful in assessing the extent of neuroinflammation associated with acute stroke and could also help to predict clinical outcomes and functional recovery, as well as to assess therapeutic strategies, such as the use of neuroprotective/anti-inflammatory drugs.

Cerebral functional asymmetry and phonological performance in dyslexic adults

Developmental dyslexia is a frequent language-based learning disorder characterized by difficulty in reading. The predominant etiologic view postulates that reading impairment is related to phonological and orthographic dysfunction. The aim of this fMRI study was to evaluate the neural bases of phonological processing impairment in remediated dyslexic adults (DD). We used a rhyming words judgment task contrasted with an unreadable fonts font-matching judgment task to compare patterns of activation and functional asymmetry in DD and normal-reading young adults. We found evidence of a link between asymmetry in inferior frontal gyrus and performance during the phonological processing. We also observed that DD recruit a network including regions involved in articulatory control in order to achieve rhyme judgment suggesting that, due to a lack of hemispheric specialization, DD recruit the latter network to achieve rhyme judgment.

Confirmation of the amyloidogenic process in posterior cortical atrophy: value of the Aβ42/Aβ40 ratio

Posterior cortical atrophy (PCA) is characterized by progressive higher-order visuo-perceptual dysfunction and praxis declines. This syndrome is related to several underlying diseases, including Alzheimer's disease (AD), sometimes involving an amyloidogenic process. The aims of the study were to 1) define cerebrospinal fluid (CSF) biomarker profiles in PCA patients compared to AD patients and 2) explore the amyloidogenic process through the Aβ(42)/Aβ(40) ratio in PCA patients to elucidate the underlying disease in vivo. CSF biomarker analysis (t-tau, p-tau, Aβ(42), and Aβ(42)/Aβ(40) ratio) and neuropsychological examination were performed in 22 PCA patients and compared with those of age-matched AD patients. Associated clinical neurological signs were investigated (e.g., extrapyramidal motor signs, myoclonus). CSF biomarker profiles did not differ significantly between the PCA and AD groups; 82% of patients with PCA fulfilled the biological criteria for typical AD with abnormal levels of the three markers and 18% of PCA patients presented atypical CSF profiles. All PCA patients with associated clinical neurological signs presented typical AD CSF profiles. The clinical presentations of these patients were similar to other PCA subjects. The Aβ(42)/Aβ(40) ratio for all PCA patients, including those with atypical CSF profiles, was decreased. Most PCA syndromes were associated with CSF biomarkers suggestive of AD, even in cases with associated clinical neurological signs. The amyloidogenic process was confirmed by the decreased Aβ(42)/Aβ(40) ratio for all patients. This analysis avoids misdiagnosis in the presence of physiologically high or low amyloid peptide production rates and provides information in vivo to improve understanding of the underlying disease in PCA.

Internal carotid artery dissection after anterior cervical disc replacement: first case report and literature review of vascular complications of the approach

We report the case of a 41-year-old woman who underwent cervical total disc replacement at C4C5 and C5C6 levels and fusion at C6C7 level through an anterior right-side approach. After anesthesia recovery, the patient presented left hemiparesia and facial palsy due to large right hemispheric stroke. Diffusion-weighted magnetic resonance imaging was performed as soon as the patient developed neurologic symptoms of stroke and revealed a right internal carotid artery dissection. Digital substraction angiography, endovascular stenting, angioplasty and thrombectomy were performed. Six months after treatment, clinical examination showed mild left-arm spasticity. To the best of our knowledge, only two cases of internal carotid artery stroke without dissection or thrombosis are reported. In conclusion, although vascular complications are rare after anterior cervical spine procedure, internal carotid artery dissection can occur. Suspected risk factors are prolonged retraction of the carotid artery and neck extension.

Review of cerebral microangiopathy and Alzheimer's disease: relation between white matter hyperintensities and microbleeds

Although Alzheimer's disease (AD) is basically considered to be a neurodegenerative disorder, cerebrovascular disease is also involved. The role of vascular risk factors and vascular disease in the progression of AD remains incompletely understood. With the development of brain MRI, it is now possible to detect small-vessel disease, whose prevalence and severity increase with age. The first types of small-vessel disease to be described were white matter hyperintensities (WMHs). More recently, small areas of signal loss on T(2)*-weighted images, also called microbleeds (MBs), have been reported. Cerebral MBs are focal deposits of hemosiderin that indicate prior microhemorrhages around small vessels, related to either ruptured atherosclerotic microvessels or amyloid angiopathy. Consequently, using brain MRI for the detection of microangiopathy may prove useful to improve our understanding of the impact of the vascular burden in AD pathology. The relationship between microangiopathy and the clinical course of AD or the conversion of mild cognitive impairment to AD remains questionable in terms of cognitive or affective symptoms, particularly if we consider MBs.

Case report: benefits of quantitative polymerase chain reaction in the clinical management of herpes simplex virus 1 infection with prominent hepatitis and unusual secondary progression

Herpes simplex virus (HSV) infection is rarely considered in the differential diagnosis of severe acute hepatitis and disseminated infection in immunocompetent adults. A case of disseminated HSV-1 infection in an 82-year-old woman initially presenting with neurological problems, signs of meningitis and prominent hepatitis was investigated. Initial diagnosis, monitoring, and follow-up were based on the application of molecular methods to cerebrospinal fluid, serum, and liver tissue samples from this patient. Following an initial full recovery, the patient presented delayed intracerebral haemorrhage and diffuse arthralgia. This atypical case, with delayed secondary progression, highlights the wide range of clinical features of HSV infection and the benefits of monitoring viral load by quantitative real-time polymerase chain reaction (PCR) during patient management.

Quadruple spontaneous cervical artery dissection following aneurysm embolization: a rare posttreatment complication

We present a unique case of multiple sCADs occurring after a ruptured intracranial aneurysm embolization. We discuss the impact of head extension during embolization as the prevailing factor in multiple artery dissections in this case and point out another cause of new-onset neurologic deficit in patients with aneurysmal SAH.

Proton MR spectroscopic imaging of basal ganglia and thalamus in neurofibromatosis type 1: correlation with T2 hyperintensities

INTRODUCTION

Neurofibromatosis type 1 (NF1) is frequently associated with hyperintense lesions on T2-weighted images called "unidentified bright objects" (UBO). To better characterize the functional significance of UBO, we investigate the basal ganglia and thalamus using spectroscopic imaging in children with NF1 and compare the results to anomalies observed on T2-weighted images.

METHODS

Magnetic resonance (MR) data of 25 children with NF1 were analyzed. On the basis of T2-weighted images analysis, two groups were identified: one with normal MR imaging (UBO- group; n = 10) and one with UBO (UBO+ group; n = 15). Within the UBO+ group, a subpopulation of patients (n = 5) only had lesions of the basal ganglia. We analyzed herein seven regions of interest (ROIs) for each side: caudate nucleus, capsulo-lenticular region, lateral and posterior thalamus, thalamus (lateral and posterior voxels combined), putamen, and striatum. For each ROI, a spectrum of the metabolites and their ratio was obtained.

RESULTS

Patients with abnormalities on T2-weighted images had significantly lower NAA/Cr, NAA/Cho, and NAA/mI ratios in the lateral right thalamus compared with patients with normal T2. These abnormal spectroscopic findings were not observed in capsulo-lenticular regions that had UBO but in the thalamus region that was devoid of UBO.

CONCLUSION

Multivoxel spectroscopic imaging using short-time echo showed spectroscopic abnormalities in the right thalamus of NF1 patients harboring UBO, which were mainly located in the basal ganglia. This finding could reflect the anatomical and functional interactions of these regions.

Preserved subcortical volumes and cortical thickness in women with sexual abuse-related PTSD

Posttraumatic stress disorder (PTSD) has been frequently associated with volumetric reductions of grey matter structures (e.g. hippocampus and anterior cingulate), but these results remain controversial, especially in female non-combat-related samples. The present study aimed at exploring whole-brain structures in women with sexual abuse-related PTSD on the basis of cortical and subcortical structure comparisons to a matched pair sample that was well-controlled. Seventeen young women who had experienced sexual abuse and who had a diagnosis of chronic PTSD based on the Clinician Administered PTSD Scale for DSM-IV and 17 healthy controls individually matched for age and years of education were consecutively recruited. Both groups underwent structural magnetic resonance imaging and psychiatric assessment of the main disorders according to Axis I of DSM-IV. The resulting scans were analyzed using automated cortical and subcortical volumetric quantifications. Compared with controls, PTSD subjects displayed normal global and regional brain volumes and cortical thicknesses. Our results indicate preserved subcortical volumes and cortical thickness in a sample of female survivors of sexual abuse with PTSD. The authors discuss potential differences between neural mechanisms of sexual abuse-related PTSD and war-related PTSD.

Thalamo-striatal T2-weighted hyperintensities (unidentified bright objects) correlate with cognitive impairments in neurofibromatosis type 1 during childhood

Learning disabilities represent the main childhood complication in neurofibromatosis type 1 (NF1). Patients frequently exhibit T2-weighted hyperintensities called unidentified bright objects (UBOs) on brain magnetic resonance imaging (MRI), with unclear relationship to such cognitive disabilities. This study aimed to determine whether thalamo-striatal UBOs correlate with cognitive disturbances. Thirty-seven NF1 children were studied: 24 with UBOs (18 of which were thalamo-striatal UBOs), and 13 without UBOs. NF1 subjects carrying thalamo-striatal UBOs had significantly lower IQs and visuospatial performances than those without UBOs in this location. These results suggest that UBOs may contribute to NF1 cognitive impairments through thalamo-cortical dysfunction.

Atypical activation of the mirror neuron system during perception of hand motion in autism

Disorders in the autism spectrum are characterized by deficits in social and communication skills such as imitation, pragmatic language, theory of mind, and empathy. The discovery of the "mirror neuron system" (MNS) in macaque monkeys may provide a basis from which to explain some of the behavioral dysfunctions seen in individuals with autism spectrum disorders (ASD).We studied seven right-handed high-functioning male autistic and eight normal subjects (TD group) using functional magnetic resonance imaging during observation and execution of hand movements compared to a control condition (rest). The between group comparison of the contrast [observation versus rest] provided evidence of a bilateral greater activation of inferior frontal gyrus during observation of human motion than during rest for the ASD group than for the TD group. This hyperactivation of the pars opercularis (belonging to the MNS) during observation of human motion in autistic subjects provides strong support for the hypothesis of atypical activity of the MNS that may be at the core of the social deficits in autism.

Anterior cerebrospinal fluid leaks in children and adults: five years experience

OBJECTIVES

To describe surgical experience in the repair of anterior skull base defects, we studied patients with congenital or acquired defects. According to a multidisciplinary evaluation, all subjects underwent surgery performed by an ENT surgeon in order to avoid craniotomy.

DESIGN

Retrospective study of patients who were treated for an anterior skull base defect between 2000 and 2005 at a tertiary referral centre.

MATERIALS AND METHODS

Twelve patients had surgery to correct anterior skull base defects. Four patients had spontaneous anterior basal defect and eight had a post-traumatic cerebrospinal fluid (CSF) leakage. The diagnosis was made with imaging studies: Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) scans, possibly supplemented by a cisternography. The defects were repaired using the endoscopic endonasal approach excepted in frontal sinus location.

RESULTS

CT and MRI scans demonstrated the defect in all but two cases. In one of them, MR cisternography showed the intranasal sac and in the other CT cisternography demonstrated a CSF fistula without any bone defect at the ethmoid roof. After surgery, the follow-up period was at least 16 months (mean 26 months). Success rate at first attempt was 83%. Two adults needed a second surgical repair with successful outcome in one, increasing the success rate to 92% after the second attempt. One female patient, obese with a body mass index > 30 and hydrocephaly, had a recurrence of CSF leakage despite surgical revision. Postoperative imaging studies, CT scan or MRI, showed that the defect had successfully been repaired in 11 patients.

CONCLUSION

High-resolution CT scan, MRI with or without cisternography, should investigate osteo-meningeal defect. Our report confirms that endonasal surgical techniques are useful for treating meningoceles and meningo-encephaloceles. The external route is to be preferred when the lesion is located in the apex of the frontal sinus.

The Feasibility of Ultrasound to Assess Subglottic Diameter

BACKGROUND

In healthy patients, the narrowest diameter of the subglottic upper airway is the width of the air-column at the level of the cricoid cartilage. This diameter governs the selection of the endotracheal tube size, as excessive tube diameter may damage the tracheal mucosa leading to postextubation stridor or subglottic stenosis. Unfortunately, selecting endotracheal tube size based on height, weight, or age does not reliably lead to the proper tube. The knowledge of airway diameter, especially using a bedside noninvasive tool, could therefore be helpful in anesthesia and intensive care.

METHODS

We studied 19 healthy volunteers (27 +/- 3 yr, nine females) to compare the transverse diameter of the cricoid lumen assessed by ultrasonography and magnetic resonance imaging.

RESULTS

We found a strong correlation between the two techniques (r = 0.99, P < 0.05) confirmed by Bland-Altman analysis with a bias of 0.14 mm, a precision of 0.33 mm, and limits of agreement of -0.68 mm/0.96 mm.

CONCLUSION

In young healthy adults, ultrasonography appeared to be a reliable tool to assess the diameter of the subglottic upper airway.

Malformations corticales et épilepsie : apport de l’IRM

Malformations of cortical development are increasingly recognized as important causes of epilepsy, developmental delay and other neurological disorders. Our purpose is to present the relevance of the MRI in these pathologies with the clinical, genetic and therapeutic aspects. This classification is based on the three fundamental events of cortical formation: proliferation of neurons and glie in the periventricular zone, migration of postmitotic neurons to the periphery, subsequent cortical organization. MR analysis evaluates particularly the cortical thickness, sulcal and cortical morphology, gray-white matter junction, and looks for gray matter in abnormal location. These data coupled with the familial history, the seizure characteristics and genetic findings should allow an appropriate classification of the lesions. MR imaging allows the detection and classification of cortical malformations. MR imaging findings are primordial to consider surgery when the epilepsy becomes refractory to the anti-epileptic drugs. An adequate classification of these malformations should help to provide to the family an appropriate counseling both in terms of genetics and outcome.