Real-Time Estimation of Core Infarct in Angiography Using Collateral Flow.

BACKGROUND AND PURPOSE: In order to attribute a diagnostic value to angiographic runs performed before revascularization, we aimed at developing a regional evaluation of leptomeningeal collateral flow that can be used to detect and predict infarction when performing stroke endovascular procedures. MATERIALS AND METHODS: We evaluated all consecutive patients treated for occlusions in the anterior circulation in our center between 2009 and 2013, with MRI imaging performed before the endovascular procedure. Two readers performed an evaluation of collateral circulation in 5 cortical regions based on the vascular anatomy. Regional scores were correlated with the presence of infarction in the same cortical sector on pretreatment and follow-up imaging. Global collateral scores for each patient were correlated with infarct volumes. RESULTS: In 89 patients with 408 cortical regions, we found a significant correlation between the degree of zonal collateral flow and the absence of infarction in the same zone on pretreatment imaging. In a subgroup of 37 recanalized patients (Thrombolysis in Cerebral Infarction scale 3) with 173 cortical zones, retrograde collateral flow to the proximal M4 segment predicted the absence of infarction within the same zone on follow-up imaging (positive predictive value 88.7%). We found good inter-rater agreement for the presence of collateral flow to the M4 proximal segment or further - k = 0.77 (p = 0.05, 95% CI 0.66-0.88). Global collateral scores correlated with infarct volume on initial imaging; all patients with scores ≥4 had infarct volumes ≤70 ml, whereas all patients with global collateral scores ≤1 had infarct volumes ≥70 ml. CONCLUSION: Anatomic collateral flow evaluation using the angiographic runs performed during stroke endovascular procedures can provide a real-time estimation of the volume and location of core infarct. For each cortical region, good collateral flow is associated with the absence of infarct on pre-treatment imaging, and is predictive of the absence of infarct on follow-up imaging in recanalized patients.

Stroke Mimics in a Stroke Care Pathway Based on MRI Screening.

BACKGROUND: Since the use of tissue plasminogen activator for acute ischemic stroke (IS), stroke care pathways have been developed for patients with suspicion of acute stroke. The aim of this prospective observational study was to analyze the stroke mimic (SM) characteristics in patients who were part of our stroke care pathway. METHODS: All consecutive patients admitted in the code stroke within a 1-year period were prospectively enrolled in this study. Patients with a sudden onset of neurological focal deficit in a time window less than 4H30 as indicated for intravenous thrombolysis, had been accepted in the pathway by a neurologist who was directly contactable by the prehospital emergency medical service 24 h per day. Patients arrived directly on the MRI site without passing by the emergency department. A clinical neurological evaluation and a brain MRI with tri-dimensional time-of-flight magnetic resonance angiography were performed. The FAST score was calculated a posteriori. The final discharge diagnosis was concluded either immediately after both neurological examination and cerebrovascular neuroimaging or after other relevant investigations. We classified the discharge diagnosis into neurovascular diseases (NVDs) and into SM. RESULTS: There were 1,361 consecutive patients admitted for suspicion of acute stroke. Sixty-two percent (n = 840) had an NVD including IS (n = 529), transient ischemic attacks (n = 236), intracranial hemorrhages (n = 68), cerebral venous thrombosis (n = 3) and neurovascular medullar pathologies (n = 4). SM represented 38% of cases (n = 521) and the most frequent discharge diagnosis was defined as headaches (18.6%), psychological disorders (16.7%), peripheral vertigo (11.9%) and epilepsy (10.6%). The comparison between the characteristics of the NVD and those of the SM groups showed some significant differences: in the SM group, women were more represented, patients were younger and the NIHSS was lower than in the NVD group. All cardiovascular risk factors were more represented in the NVD group. Concerning the symptoms, motor deficit, speech disturbances, homonymous lateral hemianopia and head and gaze deviation were more represented in the NVD group, whereas vertigo, non-systematized visual trouble, headache, confusion, weakness, neuropsychological symptoms, seizure and chest pain were significantly more frequent in the SM group. The negative predictive value of the FAST score was 64% and the positive predictive value was 76%. CONCLUSIONS: A rate of SM up to 38% of the code stroke system confirms the difficulty to distinguish clinically a stroke from another diagnosis. In this study, using cerebral MRI in first intention was of special interest in patients with acute neurological symptoms to differentiate an NVD from an SM.

First Case of Human Cerebral Taenia martis Cysticercosis.

Taenia martis is a tapeworm affecting mustelids, with rodents serving as intermediate hosts. The larval stage (cysticercus) has been found before only rarely in humans or primates. We hereby describe a case of cerebral T. martis cysticercosis in a French immunocompetent patient, confirmed by DNA analyses of biopsy material.

Ischaemic strokes with reversible vasoconstriction and without thunderclap headache: a variant of the reversible cerebral vasoconstriction syndrome?

BACKGROUND: Reversible vasoconstriction (RV) may cause ischaemic stroke (IS) in the absence of any other defined stroke aetiology. The three objectives of our study were to evaluate the frequency of RV in a prospective series of young IS patients, to describe the detailed clinical-radiological features in the patients with RV and IS, and to compare these characteristics with those of reversible cerebral vasoconstriction syndrome (RCVS). METHODS: We identified between October 2005 and December 2010, 159 consecutive young patients (<45 years) hospitalized for an acute IS confirmed by cerebral magnetic resonance imaging. An extensive diagnostic work-up was performed including toxicological urinary screening for cannabis, cocaine and amphetamines, and the usual biological, cardiac and vascular investigations for an IS in the young. We specifically studied patients with IS and RV, which was defined as multifocal intracranial arterial stenoses confirmed by intracranial arterial imaging that resolved within 3-6 months. RESULTS: Out of 159 patients with IS, 21 (13%, 12 males, 9 females; mean age 32 years) had multifocal cerebral arterial stenoses that were fully reversible at 3-6 months, and no other cause for stroke. IS were located on posterior territory in 71% of cases, and vasoconstriction predominated on posterior cerebral and superior cerebellar arteries. Precipitating factors of IS and RV were the use of cannabis resin (n = 14), nasal decongestants (n = 2) and triptan (n = 1). Most cases (74%) had unusual severe headache, but none had thunderclap headache. None of 21 cases had reversible posterior leukoencephalopathy, cortical subarachnoid or intracerebral haemorrhage. CONCLUSION: RV was the sole identified cause of IS in 13% of our cohort. These young patients with IS and RV may have a variant of RCVS, related to an increased susceptibility to vasoactive agents in some individuals. RV in our patients differs from the classical characteristics of RCVS by the absence of thunderclap headache, reversible brain oedema and subarachnoid or intracranial haemorrhage. Intracranial arteries should be looked for, by appropriate vascular imaging, in young patients with IS at the acute stage and during the follow-up period.

Flow control using Scepter™ balloons for Onyx embolization of a vein of Galen aneurysmal malformation.

PURPOSE: We present a technical development of the endovascular treatment technique for vein of Galen aneurysmal malformation, using Onyx™ (ethylene vinyl alcohol copolymer) delivered under flow control through double-lumen balloon microcatheters. MATERIALS AND METHODS: An 11-month-old patient that initially presented with increasing head circumference was diagnosed with mural type vein of Galen aneurysmal malformation. Complete cure was obtained in a single endovascular treatment session. Onyx was delivered simultaneously through two double-lumen balloon microcatheters (Scepter™, Microvention, Terumo Group). In both arterial feeders, balloon inflation occluded the high-flow arterial-venous shunting and thus facilitated the controlled propagation of the embolic product in the afferent artery and the shunt point while preventing distal migration into the venous system. RESULTS: Two years post-procedure, MR imaging showed persistent occlusion of arterial-venous shunts with complete regression of the venous dilatation. On clinical examination, the patient had no neurological deficits, and no cognitive impairment was detected at neuropsychological testing. CONCLUSION: The use of double-lumen balloon microcatheters for flow control during delivery of Onyx represents a viable alternative for the endovascular treatment of vein of Galen aneurysmal malformations.

High frequency of intracranial arterial stenosis and cannabis use in ischaemic stroke in the young.

BACKGROUND: Leading aetiologies of ischaemic stroke in young adults are cervico-cerebral arterial dissections and cardio-embolism, but the causes remain undetermined in a considerable proportion of cases. In a few reports, intracranial arterial stenosis has been suggested to be a potential cause of ischaemic stroke in young adults. The aim of our work was to evaluate the frequency, characteristics and risk factors of intracranial arterial stenosis in a prospective series of young ischaemic stroke patients. METHODS: The study was based on a prospective consecutive hospital-based series of 159 patients aged 18-45 years who were admitted to our unit for an acute ischaemic stroke from October 2005 to December 2010. A structured questionnaire was used in order to assess common vascular risk factors such as hypertension, diabetes, hypercholesterolemia, use of tobacco, alcohol and illicit drugs, migraine, and, in women, oral contraceptive use. A systematic screening was performed, including the following: brain magnetic resonance imaging or, if not feasible, brain computed tomography scan, carotid and vertebral Duplex scanning and trans-cranial Doppler sonography, 3D time-of-flight magnetic resonance cerebral angiography or cerebral computed tomography angiography. Long-duration electrocardiography, trans-thoracic and trans-oesophageal echocardiography were performed and laboratory blood investigations were extensive. Urine samples were screened for cannabinoids, cocaine, amphetamine and methylene-dioxy-methamphetamine. When this initial work-up was inconclusive, trans-femoral intra-arterial selective digital subtraction angiography with reconstructed 3D images was performed. RESULTS: In this series, 49 patients (31%) had intracranial arterial stenosis. Other defined causes were found in 91 patients (57%), including cardio-embolism in 32 (20%), cervical dissection in 23 (14%), extracranial atherosclerosis in 7 (4%), haematological disorders in 7 (4%), small vessel disease in 1, and isolated patent foramen ovale in 21 (13%); in 19 patients (12%), ischaemic stroke was related to an undetermined aetiology. Comparing risk factors between patients with intracranial arterial stenosis and those with other definite causes showed that there were only two significant differences: a lower age and a higher frequency of vasoactive substances (especially cannabis) in patients with intracranial arterial stenosis. All intracranial arterial stenosis in patients who used vasoactive substances were located in several intracranial vessels. CONCLUSIONS: Intracranial arterial stenosis may be an important mechanism of stroke in young patients and it should be systematically investigated using vascular imaging. Strong questioning about illicit drug consumption (including cannabis) or vasoactive medication use should also be performed. It should be emphasized for health prevention in young adults that cannabis use might be associated with critical consequences such as stroke.

Cerebral vasculitis associated with Schistosoma mansoni infection.

BACKGROUND: Cerebral involvement in schistosomiasis is not rare, but it is underdiagnosed because of the lack of clinical suspicion and the frequency of asymptomatic forms. Neurologic complications are generally supported by granuloma formation around ectopic eggs which have migrated to the brain. Moreover, vascular lesions and cerebral arteritis have been well documented in histopathological studies. Nevertheless, cerebral vasculitis in later stages of the Schistosoma mansoni infection have not yet been described in living subjects. CASE PRESENTATION: A 28-year-old french woman had a stroke linked with cerebral vasculitis, 6 monthes after returning from Burkina-Faso. At the same time, a S. mansoni disseminated infection was diagnosed. She suffered from a new stroke after undertaking praziquantel therapy, which lead us to associate the S. mansoni infection and cerebral vasculitis. CONCLUSION: This is the first report of such association, since cerebral vasculitis has never been described in later stages of the S. mansoni infection. Although the causal link between the two pathologies could not be proved, we suggest that S. mansoni is able to cause severe vascular damage in cerebral vessels. Schistosomiasis must be investigated in the event of a brain infarct in young people, particularly in patients originating or returning from an endemic area.

Cannabis use, ischemic stroke, and multifocal intracranial vasoconstriction: a prospective study in 48 consecutive young patients.

BACKGROUND AND PURPOSE: Our objective was to evaluate the relationship between cannabis use and ischemic stroke in a young adult population. METHODS: Forty-eight consecutive young patients admitted for acute ischemic stroke participated in the study. First-line screening was performed, including blood tests, cardiovascular investigations, and urine analysis for cannabinoids. If no etiology was found, 3D rotational angiography and cerebrospinal fluid analysis were performed. A control was planned through neurovascular imaging within 3 to 6 months. RESULTS: In this series, there was multifocal intracranial stenosis associated with cannabis use in 21% (n=10). CONCLUSIONS: Multifocal angiopathy associated with cannabis consumption could be an important cause of ischemic stroke in young people.

Tacrolimus-associated posterior reversible encephalopathy syndrome after solid organ transplantation.

Tacrolimus (TAC) is an immunosuppressant drug discovered in 1984 by Fujisawa Pharmaceutical Co., Ltd. This drug belongs to the group of calcineurin inhibitors, which has been proven highly effective in preventing acute rejection after transplantation of solid organs. However, neurotoxicity and nephrotoxicity are its major adverse effects. Posterior reversible encephalopathy syndrome (PRES) is the most severe and dramatic consequence of calcineurin inhibitor neurotoxicity. It was initially described by Hinchey et al. in 1996 [N Engl J Med 1996;334:494-450]. Patients typically present with altered mental status, headache, focal neurological deficits, visual disturbances, and seizures. Magnetic resonance imaging is the most sensitive imaging test to detect this. With the more deep-going studies done recently, we have learnt more about this entity. It was noted that this syndrome is frequently reversible, rarely limited to the posterior regions of the brain, and often located in gray matter and cortex as well as in white matter. Therefore, in this review, the focus is on the current understanding of clinical recognition, pathogenesis, neuroimaging and management of TAC-associated PRES after solid organ transplantation.

Alteration of protein kinase C conformation in red blood cells: a potential marker for Alzheimer's disease but not for Parkinson's disease.

There is a growing evidence of early changes of blood cells in Alzheimer's disease (AD). We have developed an original novel method for quantifying the alteration of protein kinase C (PKC) by its fluorescence spectrum: by using Fim-1, a specific fluorescent probe made for protein kinase C that detects the conformational changes of this. We show that the PKC conformation is altered in red blood cells (RBC) from AD patients as compared to RBC from healthy controls. This alteration is independent of the patient's age and of the stage of the disease. It is not observed in the RBC of non-demented patients suffering from Parkinson's disease (PD). If PKC alteration is proven to be specific to AD as compared with other dementia, this method could be for a simple, low cost screening test among patients suspected of having AD and may have a strong predictive value.

Landau-Kleffner syndrome is not an eponymic badge of ignorance.

In a 1992 editorial article, Landau expressed the hope of collective agreement in the medical community about Landau-Kleffner syndrome (LKS) in terms of diagnosis criteria, etiology, pathophysiology and rational therapy. Since then, neurophysiological and neuroimaging studies have led to the view that LKS is an acquired aphasia, secondary to an epileptic disturbance affecting a cortical area involved in verbal processing. This fits with the hypothesis of a "functional ablation" caused by epileptic activity. Under these criteria, epileptic aphasia becomes a subgroup of the continuous spike-waves syndrome in which epileptic discharges originate from the temporal cortex. Genetic predisposition for KLS could be related to hyperexcitability and synchronization of interneurons within the perisylvian cortices, which generate the spike-waves. Activation of these waves during NREM sleep, following thalamo-cortical uncoupling, might then alter the blood brain barrier and provoke an autoimmune reaction. Interneuron hyperactivity might in turn have an antiepileptic protective effect, associated with the inhibition of a specific function, and spike-waves activity over the long term might eventuate in focal atrophy. This morphological defect might explain the poor verbal outcome in some cases of LKS. From this study we recommend a multicenter control study of good design and methodology be carried out to compare the efficacies of early versus delayed (3 months) corticosteroid treatment in patients with typical LKS that is being treated by clobazam (or diazepam) monotherapy.

Pathological Laughing: Brain SPECT Findings.

We present the case of a 40-year-old man consulting for uncontrollable episodes of laughing related to emotional lability and not systematically linked to feelings of happiness. Seven months earlier he had presented a pontine ischemic stroke related to an occlusion of the basilar and left vertebral arteries. No epileptic activity or new MRI brain lesions were found. Brain perfusion SPECT performed showed marked hypoperfusion in the right frontal inferior and temporoinsular regions, suggesting a diaschisis phenomenon caused by pontine lesions and highlighted laughing regulation pathways. The patient was successfully treated with a serotonergic reuptake inhibitor, fluoxetine.

Balloon protection of the Labbé vein during transarterial embolization of a dural arterio-venous fistula.

INTRODUCTION: Endovascular treatment of type III dural arterio-venous fistulas can be challenging if the fistulous point is close to a functionally important cortical vein. METHODS: A technique is described for temporary balloon protection of the vein of Labbé during transarterial Onyx embolization of a type III dural arterio-venous fistula. One illustrative case is presented. Careful anatomic consideration of the concerned venous segment (at the insertion point into the lateral sinus) and the choice of balloon minimized the risk of venous rupture. RESULTS: Using this method, satisfactory progression of Onyx was obtained within the arterio-venous shunt while preserving the patency of the Labbé vein. CONCLUSION: Temporary balloon protection of the Labbé vein is a feasible option to preserve its patency during embolization of dural arterio-venous fistulas. To the authors' knowledge, this is the first report on the use of temporary balloon protection of a cortical vein.

Tetrahydrocannabinol induces brain mitochondrial respiratory chain dysfunction and increases oxidative stress: a potential mechanism involved in cannabis-related stroke.

Cannabis has potential therapeutic use but tetrahydrocannabinol (THC), its main psychoactive component, appears as a risk factor for ischemic stroke in young adults. We therefore evaluate the effects of THC on brain mitochondrial function and oxidative stress, key factors involved in stroke. Maximal oxidative capacities V max (complexes I, III, and IV activities), V succ (complexes II, III, and IV activities), V tmpd (complex IV activity), together with mitochondrial coupling (V max/V 0), were determined in control conditions and after exposure to THC in isolated mitochondria extracted from rat brain, using differential centrifugations. Oxidative stress was also assessed through hydrogen peroxide (H2O2) production, measured with Amplex Red. THC significantly decreased V max (-71%; P < 0.0001), V succ (-65%; P < 0.0001), and V tmpd (-3.5%; P < 0.001). Mitochondrial coupling (V max/V 0) was also significantly decreased after THC exposure (1.8±0.2 versus 6.3±0.7; P < 0.001). Furthermore, THC significantly enhanced H2O2 production by cerebral mitochondria (+171%; P < 0.05) and mitochondrial free radical leak was increased from 0.01±0.01 to 0.10±0.01% (P < 0.001). Thus, THC increases oxidative stress and induces cerebral mitochondrial dysfunction. This mechanism may be involved in young cannabis users who develop ischemic stroke since THC might increase patient's vulnerability to stroke.

Ictal and interictal perfusion variations measured by SISCOM analysis in typical childhood absence seizures.

Single photon emission computed tomography (SPECT) is currently used in the presurgical evaluation of medically intractable partial epilepsies, but not very often, in generalized epilepsy. In the present study, we used the SISCOM procedure, which represents the fusion of MRI and ictal-interictal difference SPECT images using (99m)Tc-ECD, to study cerebral blood flow changes during the ictal and postictal phases of typical childhood absence seizures. The study was performed on four children with typical, difficult to treat absence seizures, aged 10-13 years at the time of scan. The delay between the onset of absence seizures and the injection of (99m)Tc-ECD was carefully noted. One scan was performed during the ictal phase and showed diffuse blood flow decreases, while the three other scans performed during the postictal phase, showed generalized blood flow increase. These data are consistent with most previous data reporting generalized changes in functional activity, not limited to the thalamo-cortical circuit in which absence seizures originate, and a decrease in cerebral blood flow during the ictal phase. Our data are concordant with the hypothesis that neuronal activity underlying the occurrence of spike-and-wave discharges does not seem to require an increase in metabolic demand and blood flow rates. [Published with videosequences].

Multimodal imaging-monitored progression of stroke-like episodes in a case of MELAS syndrome.

We report imaging findings during, between, and after 2 stroke-like episodes in a 45-year-old woman with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome with an A32243G mitochondrial mutation 6 years before. In November 2010, for a first episode, she showed mixed aphasia with logorrhea, disinhibition, agitation, euphoria, and a large left temporoparietal lesion. Symptomatology progressively regressed under L-arginine treatment. She was readmitted in June 2011 for a second episode with great anxiety, disorientation, impaired face recognition, worsening mixed aphasia, and a new right temporal lesion. After additional L-carnitine treatment, she remained without relapse for 14 months.

Heterogeneity of radiological spectrum in tacrolimus-associated encephalopathy after lung transplantation.

BACKGROUND: Tacrolimus-associated encephalopathy (TAC-E) is usually described under the term of posterior reversible encephalopathy syndrome (PRES). However, a large amount of data has suggested that TAC-E is not a homogenous entity: indeed, TAC-E which is often presented with atypical and potentially misleading imaging characteristics does not always correspond to PRES. OBJECTIVE: We aimed to identify the spectrum of brain MR imaging of TAC-E and discuss the underlying pathophysiological features. METHODS: From September 2008 to October 2010, the neurological statuses of 45 patients, who underwent lung transplantation with TAC as posttransplantation immunosuppressive therapy, were regularly assessed in a prospective study. MRI was repeatedly performed, until recovery, in patients who developed central neurological symptoms. RESULTS: Symptoms suggestive of encephalopathy occurred in five out of 45 patients (11.1%). According to our MRI study, two patients presented with reversible bilateral and relatively symmetric subcortical white matter edema with proximal vasospasms on MRA; however, three other patients were characterized by coexistence of two different lesions including laminar cortical infarcts with hemorrhagic transformation not typically found in PRES and reversible deep white matter edema, associated with distal vasospasms on MRA. CONCLUSIONS: It is considered that the mechanism of TAC-E would be more heterogenous than commonly perceived.

Endovascular treatment in two cases of bilateral ischemic stroke.

Acute bilateral intracranial large artery occlusion is a rare occurrence that can lead to bihemispheric ischemia and potentially devastating functional consequences. We discuss two cases that initially presented with unilateral symptoms and did not show signs of bilateral arterial occlusions on the initial MRI imaging. This became evident while performing the angiographic study at the beginning of the endovascular procedure. Both patients were successfully treated with bilateral mechanical thrombectomy as a complement to intravenous thrombolysis. We describe our method of simultaneous sequential bilateral thrombectomy. To our knowledge, this is the first report of successful endovascular therapy in bilateral ischemic stroke.

Robin Hood caught in Wonderland: brain SPECT findings.

We present the case of a 53-year-old woman presenting several episodes of body image distortions, ground deformation illusions, and problems assessing distance in the orthostatic position corresponding to the Alice in Wonderland syndrome. No symptoms were reported when sitting or lying down. She had uncontrolled hypertension, hyperglycemia, hypercholesterolemia, and a history of head trauma. Her condition had been diagnosed with left internal carotid artery dissection 2 years earlier. Brain SPECT with 99mTc-ECD performed after i.v. injection of the radiotracer in supine and in standing positions showed hypoperfusion in the healthy contralateral frontoparietal operculum (Robin Hood syndrome), deteriorating when standing up.