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Objective: To compare the effects of high-frequency (10 Hz) versus low-frequency (1 Hz) repetitive Transcranial Magnetic Stimulation (rTMS) on motor recovery and functional reorganization of the cortical motor network during the early phase of stroke., Methods: Forty-six hospitalized, first-ever ischemic stroke patients in early stage (within two weeks) with upper limb motor deficits were recruited. They were randomly allocated to three groups with 10 Hz ipsilesional rTMS, 1 Hz contralesional rTMS, and sham rTMS of five daily session. All patients underwent motor function (Upper Extremity Fugl-Meyer), neurophysiological and resting-state  functional Magnetic Resonance Imaging (fMRI) (rs-fMRI) assessments before and after rTMS intervention. Motor recovery (△Fugl-Meyer Assessment) was defined as motor function changes before and after rTMS intervention. Motor function assessment was reevaluated at time point of three month follow-up., Results: The two real rTMS groups manifested greater motor improvements than the sham group. The effect sustained for at least 3 months after the end of the treatment sessions. Compared with the sham group, 10 Hz ipsilesional rTMS group presented increased resting-state functional connectivity (FC) between ipsilesional primary motor cortex (M1) and contralesional M1 (P = .007), whereas 1 Hz contralesional rTMS group presented increased FC between contralesional M1 and ipsilesional supplementary motor area (P = .010), which were positively correlated with motor recovery (P < .05)., Conclusion: Beneficial effect of rTMS on motor recovery might be underlaid by increased FC between stimulating site and the remote motor areas, highlighting the motor network reorganization mechanism of rTMS in early post-stroke phase.

Purpose: This study was aimed at evaluating the motor cortical excitability and connectivity underlying the neural mechanism of motor deficit in acute stroke by the combination of functional magnetic resonance imaging (fMRI) and electrophysiological measures., Methods: Twenty-five patients with motor deficit after acute ischemic stroke were involved. General linear model and dynamic causal model analyses were applied to fMRI data for detecting motor-related activation and effective connectivity of the motor cortices. Motor cortical excitability was determined as a resting motor threshold (RMT) of motor evoked potential detected by transcranial magnetic stimulation (TMS). fMRI results were correlated with cortical excitability and upper extremity Fugl-Meyer assessment scores, respectively., Results: Greater fMRI activation likelihood and motor cortical excitability in the ipsilesional primary motor area (M1) region were associated with better motor performance. During hand movements, the inhibitory connectivity from the contralesional to the ipsilesional M1 was correlated with the degree of motor impairment. Furthermore, ipsilesional motor cortex excitability was correlated with an enhancement of promoting connectivity in ipsilesional M1 or a reduction of interhemispheric inhibition in contralesional M1., Conclusions: The study suggested that a dysfunction of the ipsilesional M1 and abnormal interhemispheric interactions might underlie the motor disability in acute ischemic stroke. Modifying the excitability of the motor cortex and correcting the abnormal motor network connectivity associated with the motor deficit might be the therapeutic target in early neurorehabilitation for stroke patients.

Background: Early neurological deterioration (END) is an important factor associated with worse clinical outcome in minor strokes. Early magnetic resonance imaging (MRI) findings can provide better sensitivity to delineate stroke pathophysiology and have diagnostic value associated with causative mechanisms. The aim of this study was to investigate the relationship between early MRI finding and the presence of END in minor stroke patients with lesions in the middle cerebral artery (MCA) territory.Methods: Consecutive MCA minor stroke patients who were admitted to our center within 24 hours of symptom onset were included in this study. All patients underwent MRI within 24 hours of admission. We analyzed baseline characteristics, infarction patterns, and treatment algorithms. The correlation between early MRI findings and END, defined as National Institutes of Health Stroke Scale score increasing more than 2 points during 72 hours after admission, was also determined.Results: Across 211 patients meeting entry criteria between January 2010 and December 2013, internal border-zone (IBZ) infarcts on early MRI scan were observed in 23 of 65 patients with END (35.4%) and in 18 of 146 patients without END (12.3%, P < .001). Patients with IBZ infarcts were found to have more hyperlipidemia, less perforating artery infarcts, more pial artery infarcts, more cortical border-zone infarcts and more ipsilateral large arterial stenosis. Logistic regression analysis revealed that IBZ infarct was independently associated with END after adjustment for other factors (odds ratio, 2.50; 95% confidence interval, 1.09-5.74; P = .031).Conclusions: Early MRI patterns of IBZ infarction are associated with END in minor stroke patients with acute infarcts of the MCA territory. [ABSTRACT FROM AUTHOR]

Background: Hyperintense vessels (HVs) on fluid-attenuated inversion recovery (FLAIR) are frequently observed in acute ischemic stroke (AIS). The presence of HVs represents altered blood flow from collaterals distal to arterial occlusion or stenosis. This study aimed to evaluate the prognostic value of HVs in AIS. Methods: Fifty-four consecutive patients with acute middle cerebral artery occlusion were enrolled in the study. The location and extent of the HVs was determined by FLAIR. Clinical data were obtained and compared between patients with different grades of HVs. Additionally, the relationship between distal HVs and leptomeningeal collaterals (LMCs) was assessed using angiography. Results: HVs were observed in 41 (75.9%) of the 54 patients enrolled. The initial NIHSS score was lower (p < 0.001) and the infarction volume was smaller (p < 0.001) in patients with distal HVs. Adjusting of other factors, regression analysis revealed that distal HVs are an independent predictor of a favorable outcome at 90 days (p = 0.006; OR 0.049; 95% CI 0.006-0.420). Furthermore, the presence of distal HVs was correlated with the presence of LMCs. Conclusion: Distal HVs may be a marker for LMCs and act as a predictor of a favorable clinical outcome for patients with AIS. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract: Objective: This study was aimed to evaluate relationship between hyperintense vessels (HV) on fluid-attenuated inversion recovery (FLAIR) and artery steno-occlusion related intracerebral collaterals. Materials and methods: A total of 233 patients with 260 atherosclerotic lesions in the M1 segment of the middle cerebral artery (MCA) were examined with FLAIR and digital subtraction angiography (DSA). HV were graded as 0, 1, 2 and 3 by its distributions in the MCA territory. Grade 0 indicated no HV; Grade 1 indicated the HV limited in Sylvian fissure; Grade 2 indicated the HV limited in Sylvian fissure and the temporal-occipital junction; Grade 3 indicated the HV extended to frontal-parietal lobes. Collateral blood flows were classified by DSA results. The relationship between HV grades and patterns of collateral flows was analyzed. Results: HV were observed in 76 out of 260 hemispheres. For patients with Grade 1 HV, most of their collateral flows (80.8%) were antegrade; for patients with Grade 2, the retrograde leptomeningeal flows were commonly manifested as anterior cerebral artery to MCA (75%); for patients with Grade 3 HV, most of the retrograde leptomeningeal flows were manifested as posterior cerebral artery to MCA (81.8%). As the grade HV increased, the frequency of retrograde leptomeningeal collateral from ACA to MCA decreased (100% to 75% and to 18.2%), and increased (0% to 25% and to 81.8%) for the retrograde leptomeningeal collateral via PCA to MCA (P <0.001). Conclusions: The HV could assess non-invasively intracerebral collaterals in patients with steno-occlusive lesions of M1 segment of MCA. [Copyright &y& Elsevier]