Chronic Middle Cerebral Artery Research Articles

Analysis of the posterior cerebral perfusion status and clinical prognostic value in chronic unilateral middle cerebral artery occlusion using SWAN combined with 3D-ASL.

To investigate the predictive value of T2 star-weighted angiography (SWAN) combined with 3-dimensional (3D) arterial spin labeling (3D-ASL) to assess cerebral perfusion status and clinical prognosis in chronic unilateral middle cerebral artery (MCA) M1 occlusion. This study included 55 patients diagnosed with chronic unilateral MCA M1 occlusion using 3D time-of-flight magnetic resonance angiography between January 2018 and July 2022. Based on the prominent vessel sign (PVS) shown in the SWAN sequence, the patients were divided into PVS-positive (n = 26) and PVS-negative (n = 29) groups. Cerebral blood flow (CBF) was selected in the affected regions of the frontal, parietal, and temporal lobes (regions of interest = 200 ± 20 mm2) using pseudo-color maps in the 3D-ASL sequence. Each patient was followed up for ischemic cerebrovascular disease within 12 months of diagnosis. The collected data were statistically analyzed to evaluate the predictive value of SWAN and 3D-ASL for the clinical prognosis of patients with chronic unilateral MCA M1 occlusion. Patients were divided into 2 groups based on the occurrence of an ischemic cerebrovascular event within 12 months (ischemic cerebrovascular event [acute ischemic stroke + transient ischemic attack] and non-ischemic cerebrovascular event groups, including 30 and 25 cases, respectively). The incidence of ischemic cerebrovascular events within 12 months was significantly higher in the PVS-positive group than in the PVS-negative group (92.31% vs 20.69%). Furthermore, the CBF values of the affected frontal, parietal, and temporal lobes were significantly lower in the ischemic cerebrovascular event group than in the non-ischemic cerebrovascular event group (P < .05). According to the receiver operating characteristic curve, the CBF values of the affected frontal, parietal, and temporal lobes in patients with chronic unilateral MCA M1 occlusion strongly correlated with ischemic cerebrovascular disease within 12 months. PVS-negative display and good collateral circulation were closely related to clinical prognosis in patients with chronic unilateral MCA M1 occlusion.

386 Stereotactic Implantation of Autologous Mesenchymal Stem Cells Improves Neurological Outcomes in a Rat Model of Chronic Middle Cerebral Artery Stroke

INTRODUCTION: Limited treatment options exist for patients with chronic infarcts. Multipotent adult mesenchymal stem cells (MSC) show promise as a treatment for chronic stroke. Allogeneic MSCs have been implanted successfully in chronic stroke1,2. However, no literature evaluates the use of autologous MSCs delivered via stereotactic implantation. Autologous MSCs provide safety and accessibility benefits. METHODS: Male Sprague-Dawley rats underwent transient right MCAO for 120 minutes. Brain MRI and sensorimotor behavior were used to evaluate stroke. Sixteen days post stroke, tibial bone marrow was aspirated and MSCs were grown in a closed bioreactor. At 28 days post stroke, 3 trajectories of MSCs were implanted in the peri-infarct zone using a stereotactic robot. The treatments consisted of group 1 (5 x 106 cell dose, N = 6), group 2 (1 x 106 cell dose, N = 6) and a control group (saline injection, N = 9). In a second cohort of animals, Q-dot labeled autologous MSCs were tracked in the brain for 7 or 30 days. RESULTS: Behavior as determined by the modified neurological severity score (0-16) significantly improved in both groups. Stroke volume did not decrease. Histological analysis confirmed increased astrocyte and microglia presence in the affected hemisphere. Quantum dot analysis of injections showed presence of MSCs along trajectory as well as targeting perilesional brain tissue at 7 and 30 days post-implantation. CONCLUSIONS: Stereotactic injection of autologous MSCs represent an effective treatment for chronic stroke. Cells were effective at the lowest dose studied, with no added benefit at higher cell dosages. Unlike allogeneic MSCs which disappear over days to weeks3, autologous MSCs persist long term in the brain, potentially providing continued benefit. This treatment warrants human trials to study its effectiveness.

Specific disruption of the ventral anterior temporo-frontal network reveals key implications for language comprehension and cognition

Recent investigations have raised the question of the role of the anterior lateral temporal cortex in language processing (ventral language network). Here we present the language and overall cognitive performance of a rare male patient with chronic middle cerebral artery cerebrovascular accident with a well-documented lesion restricted to the anterior temporal cortex and its connections via the extreme capsule with the pars triangularis of the inferior frontal gyrus (i.e. Broca’s region). The performance of this unique patient is compared with that of two chronic middle cerebral artery cerebrovascular accident male patients with damage to the classic dorsal posterior temporo-parietal language system. Diffusion tensor imaging is used to reconstruct the relevant white matter tracts of the three patients, which are also compared with those of 10 healthy individuals. The patient with the anterior temporo-frontal lesion presents with flawless and fluent speech, but selective impairment in accessing lexico-semantic information, in sharp contrast to the impairments in speech, sentence comprehension and repetition observed after lesions to the classic dorsal language system. The present results underline the contribution of the ventral language stream in lexico-semantic processing and higher cognitive functions, such as active selective controlled retrieval.

Disruptions in Structural and Functional Connectivity Relate to Poststroke Fatigue.

Introduction: Poststroke fatigue (PSF) is a disabling condition with unclear etiology. The brain lesion is thought to be an important causal factor in PSF, although focal lesion characteristics such as size and location have not proven to be predictive. Given that the stroke lesion results not only in focal tissue death but also in widespread changes in brain networks that are structurally and functionally connected to damaged tissue, we hypothesized that PSF relates to disruptions in structural and functional connectivity. Materials and Methods: Twelve patients who incurred an ischemic stroke in the middle cerebral artery (MCA) territory 1-3 years prior, and currently experiencing a range of fatigue severity, were enrolled. The patients underwent structural and resting-state functional magnetic resonance imaging (MRI). The structural MRI data were used to measure structural disconnection of gray matter resulting from lesion to white matter pathways. The functional MRI data were used to measure network functional connectivity. Results: The patients showed structural disconnection in varying cortical and subcortical regions. Fatigue severity correlated significantly with structural disconnection of several frontal cortex regions in the ipsilesional (IL) and contralesional hemispheres. Fatigue-related structural disconnection was most severe in the IL rostral middle frontal cortex. Greater structural disconnection of a subset of fatigue-related frontal cortex regions, including the IL rostral middle frontal cortex, trended toward correlating significantly with greater loss in functional connectivity. Among identified fatigue-related frontal cortex regions, only the IL rostral middle frontal cortex showed loss in functional connectivity correlating significantly with fatigue severity. Conclusion: Our results provide evidence that loss in structural and functional connectivity of bihemispheric frontal cortex regions plays a role in PSF after MCA stroke, with connectivity disruptions of the IL rostral middle frontal cortex having a central role. Impact statement Poststroke fatigue (PSF) is a common disabling condition with unclear etiology. We hypothesized that PSF relates to disruptions in structural and functional connectivity secondary to the focal lesion. Using structural and resting-state functional connectivity magnetic resonance imaging (MRI) in patients with chronic middle cerebral artery (MCA) stroke, we found frontal cortex regions in the ipsilesional (IL) and contralesional hemispheres with greater structural disconnection correlating with greater fatigue. Among these fatigue-related cortices, the IL rostral middle frontal cortex showed loss in functional connectivity correlating with fatigue. These findings suggest that disruptions in structural and functional connectivity play a role in PSF after MCA stroke.

Evaluating iron deposition in gray matter nuclei of patients with unilateral middle cerebral artery stenosis using quantitative susceptibility mapping

Iron mediated oxidative stress is involved in the process of brain injury after long-term ischemia. While increased iron deposition in the affected brain regions was observed in animal models of ischemic stroke, potential changes in the brain iron content in clinical patients with cerebral ischemia remain unclear. Quantitative susceptibility mapping (QSM), a non-invasive magnetic resonance imaging technique, can be used to evaluate iron content in the gray matter (GM) nuclei reliably. In this study, we aimed to quantitatively evaluate iron content changes in GM nuclei of patients with long-term unilateral middle cerebral artery (MCA) stenosis/occlusion-related cerebral ischemia using QSM.Forty-six unilateral MCA stenosis/occlusion patients and 38 age-, sex- and education-matched healthy controls underwent QSM. Clinical variables of history of hypertension, diabetes, hyperlipidemia, hyperhomocysteinemia, smoking, and drinking in all patients were evaluated. The iron-related susceptibility of GM nucleus subregions, including the bilateral caudate nucleus (CN), putamen (PU), globus pallidus (GP), thalamus, substantia nigra (SN), red nucleus, and dentate nucleus, was assessed. Susceptibility was compared between the bilateral GM nuclei in patients and controls. Receiver operating characteristic curve analysis was used to evaluate the efficacy of QSM susceptibility in distinguishing patients with unilateral MCA stenosis/occlusion from healthy controls. Multiple linear regression analysis was used to evaluate the relationship between ipsilateral susceptibility levels and clinical variables.Except for the CN, the susceptibility in most bilateral GM nucleus subregions was comparable in healthy controls, whereas for patients with unilateral MCA stenosis/occlusion, the ipsilateral PU, GP, and SN exhibited significantly higher susceptibility than the contralateral side (all P < 0.05). Compared with controls, susceptibility of the ipsilateral PU, GP, and SN and of contralateral PU in patients were significantly increased (all P < 0.05). The area under the curve (AUC) was greater for the ipsilateral PU than for the GP and SN (AUC = 0.773, 0.662 and 0.681; all P < 0.05). Multiple linear regression analysis showed that the increased susceptibility of the ipsilateral PU was significantly associated with hypertension, of the ipsilateral GP associated with smoking, and of the ipsilateral SN associated with diabetes (all P < 0.05).Our findings provide support for abnormal iron accumulation in the GM nuclei after chronic MCA stenosis/occlusion and its correlation with some cerebrovascular disease risk factors. Therefore, iron deposition in the GM nuclei, as measured by QSM, may be a potential biomarker for long-term cerebral ischemia.

A pilot [11C]PBR28 PET/MRI study of neuroinflammation and neurodegeneration in chronic stroke patients

Neuroinflammation occurs in response to acute ischemic stroke, and has been speculated to underlie secondary poststroke pathologies, such as depression, that often develop over time poststroke. However, no study has examined whether neuroinflammation is present in chronic stroke patients (e.g., ​≥ ​1 year poststroke). This study tested whether neuroinflammation is present in chronic stroke patients, and is associated with neurodegeneration, using [11C]PBR28 PET and diffusion MRI.Eight patients with middle cerebral artery (MCA) ischemic stroke incurred 1–3 years prior and 16 healthy controls underwent [11C]PBR28 PET to measure glial activation and diffusion MRI to measure microstructural integrity by mean diffusivity (MD) and fractional anisotropy (FA) using an integrated PET/MRI scanner. Group differences in [11C]PBR28 binding, MD and FA were analyzed voxelwise across the whole brain excluding the infarct zone defined as voxels containing the infarct in any patient.Compared to controls, patients showed elevations in [11C]PBR28 binding in several brain regions outside the infarct zone, including regions with presumed direct neuroanatomical connections to the infarct (e.g., ipsilesional internal capsule and thalamus) and those without known direct connections (e.g., contralesional thalamus and cingulate gyrus). Patients also showed widespread elevations in MD, with a subset of these regions having reduced FA. In patients, MD was more elevated in regions with co-localized elevations in [11C]PBR28 binding than in contralateral regions without elevations in [11C]PBR28 binding.This pilot study supports the presence of extensive glial activation along with widespread loss in microstructural integrity in non-infarcted tissue in a cohort of patients with chronic MCA stroke. The loss in microstructural integrity was greater in regions with co-localized glial activation. It is possible that stroke risk factors (e.g., hypertension) contributed to these tissue changes in patients.

Clinical analysis of low flow bypass in the treatment of chronic symptomatic middle cerebral artery occlusion

Clinical analysis of low flow bypass in the treatment of chronic symptomatic middle cerebral artery occlusion

Neurocognitive improvement after angioplasty in patients with chronic middle cerebral artery stenosis and cerebral ischemia.

The use of middle cerebral artery (MCA) angioplasty compared with drug therapy has been controversial. Few studies have reported the correlations between cognitive function improvement and MCA angioplasty. This study aimed to explore neurocognitive function after angioplasty in patients with middle cerebral artery stenosis (MCAS) and objective cerebral ischemia. We identified 14 patients diagnosed with MCAS aged 45-65 years. Neurocognitive function evaluation was performed by 2 independent clinical psychologists using the Mini-Mental State Examination (MMSE), Montreal cognitive assessment scale (MoCA), and Multi-Dimensional Psychology. All patients received general anesthesia, underwent diagnostic cerebral angiography (DSA) via the femoral route and angioplasty, and then were sent to the neurologic intensive care unit (NICU) for overnight hemodynamic and neurologic monitoring. Aspirin and clopidogrel treatments were continued for 3 months after successful intervention. Complete neurologic examinations, including assessment with the National Institutes of Health Stroke (NIHSS), and modulate RANK score (MRS) were conducted by 2 independent neurologists. The patients received a family follow-up at 1 week, 1 month, and 3 months after the interventional procedure. Neurologic sequelae, intracranial hemorrhages, and deaths were recorded as an endpoint. Follow-up clinical and imageological examinations were scheduled at 6 months after the intervention. Follow-up brain computed tomography (CT) perfusion or magnetic resonance angiography (MRA) perfusion scans performed by 2 imageological scanners were scheduled 6 months after the procedure. Angioplasty technical success was achieved in 14 parents (100%). We found that 10 patients did not have recurrent MCAS in the angioplasty site and had significant improvements in the associated brain perfusion situation and cognitive founction as compared before and after angioplasty. Also, 4 patients had evident restenosis in the angioplasty site. In the nonstenosis group, we found significant improvements in the MMSE, 3-dimensional (3D) mental rotation, simple calculation, and spatial working memory. In the recurrent stenosis group, we found no statistically significant changes in cognitive function compared with the baseline and after a 6-month follow up. There were high correlations between the changes in perfusion and the changes in word and picture memory. There was a significant correlation between the change in perfusion with MMSE (-0.522), spatial working memory (0.655), and Raven's progressive matrices test (0.637); a moderate correlation with 3D rotation (0.413), and simple calculation (-0.359); and weak correlation with visual tracking (0.026) and MoCA (0.279). Angioplasty surgery significantly improves neurocognitive function in patients with middle cerebral artery stenosis (MCAS) and objective cerebral ischemia.

New Vessels or MCA Stem: A Case of Asymptomatic Chronic Middle Cerebral Artery Occlusion on TCCS

New Vessels or MCA Stem: A Case of Asymptomatic Chronic Middle Cerebral Artery Occlusion on TCCS

EFFECT OF COMBINING TRANSCUTANEOUS ELECTRICAL NERVE STIMULATION WITH EXERCISE REGIME ON SPASTICITY AND UPPER EXTREMITY FUNCTION FOLLOWING CHRONIC MIDDLE CEREBRAL ARTERY STROKE

Background: Post stoke hemiparesis limit the upper extremity function due to development of spasticity and synergy patterns, therefore rendering the patient impaired in activities of daily living. Transcutaneous electrical nerve stimulation (TENS) has recently been used to reduce spasticity. The purpose of this study was to evaluate the effects of TENS on spasticity and upper extremity function following chronic middle cerebral artery stroke (MCA). Study design and setting: interventional study conducted on patients from clinical and hospital setting in Ahmedabad. Methods: A total of 30 patients between the age group of 35-75 years of age. Group A received TENS for 30 minutes in addition to conventional exercise therapy regime where as group B received only exercise therapy regime. The intervention was given for 5 days a week for 4 weeks. The outcome measures were Modified Ashworth scale (MAS) and Fugl Meyer assessment for upper extremity (FMA-UE). The data collected was statistically analysed by using Wilcoxon’s signed rank test for within group analysis and Mann Whitney U test for between the group analysis. Results and conclusion: Group A showed a statically (P &lt;0.05) as well as clinically significant improvement in both the outcome measures. There-fore it was concluded that TENS prove to be effective in reducing spasticity and improving upper extremity function in chronic MCA stroke. KEY WORDS: Stroke, Spasticity, TENS, Modified Ashworth scale (MAS), Fugl Meyer assessment for upper extremity (FMA-UE).

Late changes in blood–brain barrier permeability in a rat tMCAO model of stroke detected by gadolinium-enhanced MRI

ABSTRACT Objectives After cerebral ischaemia the blood–brain barrier (BBB) may be compromised and this has been observed in both clinical and preclinical studies. The timing of BBB disruption after ischaemia has long been considered to be biphasic, however some groups contest this view. Therefore, the purpose of this study was to characterize the BBB permeability timecourse in a rat model at both acute and chronic time points Methods Unilateral transient middle cerebral artery occlusion (tMCAO) was performed in 15 male Sprague Dawley rats. Change in T1-weighted MR signal before and after an injection of gadolinium-based contrast agent was calculated voxelwise to derive a BBB permeability index (BBBPI) at both early (6 h, 12 h, and 24 h) and late (7 and 14 days) time points. Results As expected, BBBPI in the non-lesioned ROI was not significantly different from pre-occlusion baseline at any time point. However, BBBPI in the ipsilateral (lesioned) ROI was statistically different to baseline at day 7 (p < 0.001) and day 14 (p < 0.01) post-tMCAO. There was a small, but not-significant increase in BBBPI in the earlier phase (at 6 hours). Discussion Our results indicate a significant late opening of the BBB. This is important as the majority of previous studies have only characterised an early acute BBB permeability in ischemia. However, the later period of increased permeability may indicate an optimal time for drug delivery across the BBB, when it is especially suited to drugs targeting delayed processes.

Interleukin-18 from neurons and microglia mediates depressive behaviors in mice with post-stroke depression

Post-stroke depression (PSD) is a common and serious complication that is affecting one thirds of stroke patients which leaves them with a poor quality of life, high mortality rate, high recurrent rate, and slow recovery. Recent studies showed that serum interleukin-18 (IL-18) level is a biomarker for patients with PSD. However, the role of IL-18 in the pathology of PSD is still unclear. In this study, we demonstrated that the IL-18 level in the ischemic brain significantly increased in mice with depression-like behaviors that were caused by the combined use of chronic spatial restraint stress and middle cerebral artery occlusion. Interestingly, IL-18 expression was mainly found in neurons at early phase and in microglia at a later phase. Injection of the exogenous IL-18 into the amygdala, but not the hippocampus or the striatum caused severe depression-like behaviors. On the contrary, the blockage of endogenous IL-18 by IL-18 binding protein, a specific antagonist of IL-18, repressed depressive phenotypes in SIR mice. IL-18 KO mice exhibited the resistance to spatial restraint stress and cerebral ischemia injury. Finally, we found that IL-18 mediated depressive behaviors by the interaction of IL-18 receptor and NKCC1, a sodium-potassium chloride co-transporter that is related to GABAergic inhibition. Administration of NKCC1 antagonist bumetanide exerted a therapeutic effect on the in IL-18-induced depressive mice. In conclusion, we demonstrated that increased IL-18 in the brain causes depression-like behaviors by promoting the IL-18 receptor/NKCC1 signaling pathway. Targeting IL-18 and its downstream pathway is a promising strategy for the prevention and treatment of PSD.

A Case Report on an Elderly Patient with Acute Hematochezia and Anemia Improved by Treatment with Korean Medicine

Introduction The aim of this study was to report the effect of Korean medicine treatments on an elderly patient with acute hematochezia and anemia Case presentation An 81-year-old female with chronic multifocal middle cerebral artery infarction had symptoms of acute hematochezia and anemia. Method The patient was treated with Korean medicine therapy. Results Treatment with Korean medicine, including herbal medicine, significantly improved the patient’s symptoms. After treatment, her hematochezia was improved and the results of a complete blood count (CBC) also improved. No side effects were observed during treatment. Conclusion Korean medicine treatment can be considered an effective treatment for acute hematochezia and anemia in an elderly patient. Keywords: lower gastrointestinal bleeding, hematochezia, anemia, Taklisodok-eum, Gakbyung-yeonsu-tang, Korean medicine

Efficiently Recording the Eye-Hand Coordination to Incoordination Spectrum.

The objective analysis of eye movements has a significant history and has been long proven to be an important research tool in the setting of brain injury. Quantitative recordings have a strong capacity to screen diagnostically. Concurrent examinations of the eye and upper limb movements directed toward shared functional goals (e.g., eye-hand coordination) serve as an additional robust biomarker-laden path to capture and interrogate neural injury, including acquired brain injury (ABI). While quantitative dual-effector recordings in 3-D afford ample opportunities within ocular-manual motor investigations in the setting of ABI, the feasibility of such dual recordings for both eye and hand is challenging in pathological settings, particularly when approached with research-grade rigor. Here we describe the integration of an eye tracking system with a motion tracking system intended primarily for limb control research to study a natural behavior. The protocol enables the investigation of unrestricted, three-dimensional (3D) eye-hand coordination tasks. More specifically, we review a method to assess eye-hand coordination in visually guided saccade-to-reach tasks in subjects with chronic middle cerebral artery (MCA) stroke and compare them to healthy controls. Special attention is paid to the specific eye- and limb-tracking system properties in order to obtain high fidelity data from participants post-injury. Sampling rate, accuracy, permissible head movement range given anticipated tolerance and the feasibility of use were several of the critical properties considered when selecting an eye tracker and an approach. The limb tracker was selected based on a similar rubric but included the need for 3-D recording, dynamic interaction and a miniaturized physical footprint. The quantitative data provided by this method and the overall approach when executed correctly has tremendous potential to further refine our mechanistic understanding of eye-hand control and help inform feasible diagnostic and pragmatic interventions within the neurological and rehabilitative practice.

Clinical Manifestations of Isolated Chronic Middle Cerebral Artery Occlusion in Relation to Angiographic Features.

Isolated chronic middle cerebral artery occlusion (ChMCAO) is not a rare condition and is known to cause hemodynamic stroke. The purpose of this study was to evaluate differences in clinical manifestations and prognosis of isolated ChMCAO in relation to angiographic features. This retrospective study enrolled 56 patients with isolated ChMCAO. In accordance with degree of anterograde collateral flow (AF) on angiography, patients were categorized into poor and good AF groups. The 2 groups were assessed and compared for the presence and recurrence of neurologic symptoms. Of 56 patients, 33 were in the poor AF group and 23 were in the good AF group. The prevalence of ischemic symptoms was significantly higher in the poor AF group compared with the good AF group (P < 0.05). During an average follow-up period of 33.8 months, recurrent ipsilateral symptoms occurred in 6 of 45 patients. The hazard ratio conferred by poor AF was 5.36 (95% confidence interval, 1.08-26.57) for recurrent symptoms. AF through the basal collateral network may be related to clinical manifestations of ChMCAO. Good AF in isolated ChMCAO may play an important role in preventing recurrence of an ischemic event.

Time-resolved 3D Rotational Angiography (4D DSA) of the Lenticulostriate Arteries: Display of Normal Anatomic Variants and Collaterals in Cases with Chronic Obstruction of the MCA.

The lenticulostriate arteries (LSA) and other perforators may play arole for collateral supply in cases with ischemia due to stenosis or occlusions of the middle cerebral artery (MCA). Purpose of this case series was to evaluate the potential of time-resolved 3D rotational angiography data sets (4D DSA) for detailed visualization of anatomic variants of LSA feeders and for display of local collaterals involving the LSA in cases with chronic MCA obstruction. Multiplanar and volume rendering reconstructions of 4D DSA data were computed in addition to standard postprocessing in 24patients who had indications for 3D rotational angiography (3DRA) of the internal carotid artery (ICA) without pathologies of the ICA, middle cerebral artery (MCA) and anterior cerebral artery (ACA) main stems (n= 18) or with stenosis or chronic occlusion of the MCA (n= 6). For acquisition of 3DRA, we used amodified digital subtraction angiography (DSA) image acquisition protocol with an extended rotation angle of 260° and aprolonged scan time of 12 s on aSiemens Axiom Artis Zee biplane neuroangiography equipment. The 4D reconstructions of existing 3DRA data were computed on adedicated workstation. Origin and course of LSA and other perforators were analyzed according to coronal multiplanar reconstructions (MPRs) with slice thicknesses between 6 and 28 mm. In all cases 4D reconstructions of the LSA were technically feasible and evaluable. As expected, origin and course of LSA showed awide range of variations: The most common pattern was acommon trunk dividing into multiple ascending branches originating from the proximal M1 (n= 5) or the proximal A1segment (n= 4). Alternatively, 8patients showed several individual branches that directly originated from the proximal M1segment of the MCA and occasionally from the A1segment of the ACA. In patients with M1stenosis or occlusion, 4 out of 6cases had local collaterals with involvement of proximal LSA trunks and anetwork parallel to the obstructed vessel segment. The 4D reconstructions were found to be equivalent (n= 16) or superior to 3D reconstructions (n= 8). The 4D DSA reconstructions provide areliable display of normal LSA variants and connections to local collateral networks in cases with chronic MCA obstruction. The possibility to select acorrect angiographic phase is advantageous compared to 3D DSA.

Abstract TP142: Cerebellar Transcranial Direct Stimulation to Augment Aphasia Therapy

Introduction: Previous studies indicate that anodal transcranial Direct Current Stimulation (A-tDCS) to left hemisphere or cathodal tDCS (C-tDCS) to right hemisphere might augment aphasia therapy to facilitate language recovery after chronic stroke and that cerebellar tDCS can augment verbal fluency and learning in healthy controls. Hypothesis: A-tDCS or C-tDCS) plus naming therapy results in improved naming performance for trained and untrained items from baseline to post-treatment compared to sham plus naming therapy in chronic aphasia. Methods: Six patients with large, chronic left middle cerebral artery (MCA) ischemic stroke and one patient with large bilateral MCA strokes participated in a randomized, double-blind, sham controlled, within-subject crossover trial (15 sessions of sham + naming therapy and 15 sessions of tDCS + naming therapy, in random order, separated by 2 months). 4 patients were randomly assigned to A-tDCS and 3 patients were assigned to C-tDCS. We used 2 mA for stimulation over right cerebellum for the first 20 minutes of computer-delivered naming therapy. Within-subjects within-treatments analysis using McNemar’s test for correlated responses to evaluate gains from each of the treatment conditions. An alpha level of p&lt;0.05 was considered significant. Results: tDCS + naming treatment produced significant gains in naming of both trained and untrained items in 3/4 patients with anodal stimulation and 3/3 patients with cathodal treatment. Sham + naming treatment produced gains for only trained items, and only in 4/7 participants. Discussion: A-tDCS or C-tDCS improved generalization of improvements to untrained stimuli after naming therapy for most patients. Results indicate potential usefulness of right cerebellar tDCS to augment naming therapy after chronic post stroke aphasia with large left or bilateral lesions.

Disrupted Saccade Control in Chronic Cerebral Injury: Upper Motor Neuron-Like Disinhibition in the Ocular Motor System.

Saccades rapidly direct the line of sight to targets of interest to make use of the high acuity foveal region of the retina. These fast eye movements are instrumental for scanning visual scenes, foveating targets, and, ultimately, serve to guide manual motor control, including eye–hand coordination. Cerebral injury has long been known to impair ocular motor control. Recently, it has been suggested that alterations in control may be useful as a marker for recovery. We measured eye movement control in a saccade task in subjects with chronic middle cerebral artery stroke with both cortical and substantial basal ganglia involvement and in healthy controls. Saccade latency distributions were bimodal, with an early peak at 60 ms (anticipatory saccades) and a later peak at 250 ms (regular saccades). Although the latencies corresponding to these peaks were the same in the two groups, there were clear differences in the size of the peaks. Classifying saccade latencies relative to the saccade “go signal” into anticipatory (latencies up to 80 ms), “early” (latencies between 80 and 160 ms), and “regular” types (latencies longer than 160 ms), stroke subjects displayed a disproportionate number of anticipatory saccades, whereas control subjects produced the majority of their saccades in the regular range. We suggest that this increase in the number of anticipatory saccade events may result from a disinhibition phenomenon that manifests as an impairment in the endogenous control of ocular motor events (saccades) and interleaved fixations. These preliminary findings may help shed light on the ocular motor deficits of neurodegenerative conditions, results that may be subclinical to an examiner, but clinically significant secondary to their functional implications.

Oxygen extraction fraction measurement using quantitative susceptibility mapping: Comparison with positron emission tomography

The purposes of this study are to establish oxygen extraction fraction (OEF) measurements using quantitative susceptibility mapping (QSM) of magnetic resonance imaging (MRI), and to compare QSM–OEF data with the gold standard 15O positron emission tomography (PET). Twenty-six patients with chronic unilateral internal carotid artery or middle cerebral artery stenosis or occlusion, and 15 normal subjects were included. MRI scans were conducted using a 3.0 Tesla scanner with a three-dimensional spoiled gradient recalled sequence. QSM images were created using the morphology-enabled dipole inversion method, and OEF maps were generated from QSM images using extraction of venous susceptibility induced by deoxygenated hemoglobin. Significant correlation of relative OEF ratio to contra-lateral hemisphere between QSM–OEF and PET–OEF was observed (r = 0.62, p < 0.001). The local (intra-section) correlation was also significant (r = 0.52, p < 0.001) in patients with increased PET–OEF. The sensitivity and specificity of OEF increase in QSM was 0.63 (5/8) and 0.89 (16/18), respectively, in comparison with PET. In conclusion, good correlation was achieved between QSM–OEF and PET–OEF in the identification of elevated OEF in affected hemispheres of patients with unilateral chronic steno-occlusive disease.

Hemodynamic alterations in unilateral chronic middle cerebral artery stenosis patients and the effect of percutaneous transluminal angioplasty and stenting: a perfusion-computed tomography study.

The Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) trial indicated that most patients with symptomatic intracranial atherosclerosis are not good candidates for percutaneous transluminal angioplasty and stenting (PTAS) because of a higher complication risk than with conservative treatment. However, enrollment of SAMMPRIS patients was based on lesion severity only, without functional imaging. To determine whether perfusion computed tomography (PCT) can effectively evaluate hemodynamic compromise in unilateral chronic middle cerebral artery stenosis and the alterations of hemodynamics after PTAS. In this prospective study, 89 patients with unilateral middle cerebral artery (MCA) stenosis/occlusion were enrolled and classified into four groups according to the degree of stenosis. Cerebral hemodynamics was evaluated by measuring cerebral blood flow (CBF), cerebral blood volume (CBV), and time to peak (TTP) in the ipsilateral and contralateral hemispheres by PCT before and after intervention with PTAS. Differences in hemodynamic parameters before and after intervention were analyzed. Three different hemodynamic patterns were observed in these patients. Patients with severe MCA stenosis (70-99%) or MCA occlusion demonstrated a significant increase of ipsilateral CBV and TTP, indicating hemodynamic compromise. Ten severe stenosis patients with recurrent ischemic symptoms despite of maximal conservative therapy were selected for PTAS. PTAS induced a rapid recovery of cerebral hemodynamics (especially TTP) at 1 week post intervention. PCT appears to be a valuable noninvasive technique to evaluate hemodynamic compromise in unilateral chronic MCA stenosis and the improvements after PTAS.