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Transcranial direct current stimulation (tDCS) is an emerging non-invasive neuromodulation technique that serves as treatment tool to neurological disorders. However, the mechanism of how the stimulation modulates ongoing brain activity and connectivity is still not fully understood. Simultaneous acquisition of neuroimaging data together with brain stimulation could allow a noninvasive examination of the brain dynamic changes during the process. In this pilot study, concurrent tDCS and fMRI was conducted in a healthy subject. Dynamic functional connectivity and effective connectivity were used to reveal the information flow. The results demonstrated that tDCS duration has important effects on the brain connectivity and the causal relationships among the brain regions. These results might reflect the fundamental mechanism of brain processing under the external stimulation.

Cerebral autoregulation (CA) is a protective mechanism that maintains cerebral blood flow at a relatively constant level despite fluctuations of cerebral perfusion pressure or arterial blood pressure. It is a universal physiological mechanism that may involve myogenic, neural control as well as metabolic regulations of cerebral vasculature in response to changes in pressure or cerebral blood flow. Traditionally, CA has been represented by a sigmoid curve with a wide plateau between about 50 mm Hg and 170 mm Hg of steady-state changes in mean arterial pressure, defined as static CA. With the advent of transcranial Doppler, measurement of cerebral blood flow in response to transient changes in arterial pressure has been used to assess dynamic CA. However, a gold standard for measuring CA is not currently available. Stroke has been the leading cause of long-term adult disability throughout the world. A better understanding of CA and its response to pathological derangements can help assess the severity of stroke, guide management decisions, assess response to interventions and provide prognostic information. The objective of this review is to provide a comprehensive insight about physiology of autoregulation, measurement methodologies and clinical applications in stroke to help build a consensus for what should be included in an internationally agreed protocol for CA testing and monitoring, and to promote its translation into clinical bedside practice for stroke management., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Background and Purpose: Intracranial vessel wall imaging using MRI has great potential as a clinical method for assessing intracranial atherosclerosis. The purpose of the current study was to compare three 3T MRI vessel wall sequences with different contrast weightings (T1w, PD, T2w) and dedicated sagittal orientation perpendicular to the middle cerebral artery, to the reconstructed sagittal image from a transverse 3D T1w volumetric isotropically reconstructed turbo spin-echo acquisition (VIRTA), and provide a clinical recommendation., Materials and Methods: The above-mentioned sequences were acquired in 10 consecutive Chinese ischemic stroke or TIA patients (age: 68 years, sex: 4 females) with angiographic-confirmed MCA stenosis at 3T. Institutional review board approval was obtained. Two raters qualitatively scored all images on overall image quality, presence of artifacts, and visibility of plaques. Data were compared using Repeated measures ANOVA and Sidak's adjusted post hoc tests., Results: All sequences except the T2w sequence were able to depict the walls of the large vessels of the Circle of Willis (p<0.05). T1w sagittal oblique VIRTA showed significantly more artifacts (p<0.01). Peripherally located plaques were sometimes missed on the sagittal sequences, but could be appreciated on the transverse T1w VIRTA., Conclusion: With the 3T multi-sequence vessel wall protocol we were able to assess the intracranial plaque with two different image contrast weightings. The sequence of preference to include in a clinical protocol would be the transverse 3D T1w VIRTA based on absence of artifacts, larger coverage including the whole Circle of Willis, and excellent lesion depiction.

Stroke patients with carotid disease have a high risk of recurrence of disease. By measuring cerebral blood flow volume (BFV) using extracranial duplex technique for clinical estimation of intracranial collaterals, we aimed to investigate the relationship between the presence of intracranial collaterals and stroke recurrence in stroke patients with carotid disease. Consecutive stroke patients indicated for carotid duplex ultrasound investigations in our hospital were recruited during three years' period. Carotid stenosis was diagnosed as ≥50% stenosis and extracranial arterial BFV was measured by using color velocity imaging quantification ultrasound (CVIQ) software. Presence of intracranial collateral flow was defined as a blood flow volume of either ≥370 mL/min in common carotid artery or ≥120 mL/min in vertebral artery. Univariate and multivariate analyses were performed to determine the independent predictors of recurrent stroke. One hundred and twelve stroke patients (19.1%) with ≤50% carotid stenosis were recruited from consecutive ischemic stroke patients. During a mean follow-up of 28.6±13.1 months, recurrent stroke was recorded in 32 (28.6%) out of the total recruited patients. Estimated by blood flow volume measured by CVIQ, the patients with intracranial collateral flow had a lower rate of recurrent stroke than those without (9.5% vs. 33%, P=0.032). After adjusting for potential confounders, the presence of CVIQ-estimated intracranial collateral flow was an independent protector of recurrent stroke (OR, 0.169; 95% CI, 0.034- 0.842; P=0.03). It could be concluded that blood supply through intracranial collateral flow estimated by CVIQ technique may protect stroke patients with carotid stenosis from suffering recurrent stroke.

Background: T2*-weighted gradient echo magnetic resonance imaging is sensitive in detecting cerebral microbleeds (MBs), but there are few reports on the risk factors of MBs in different brain regions. Therefore, we aimed to investigate whether the risk factors associated with the presence of MBs in strictly deep or lobar brain regions were different., Methods: This study consisted of 696 consecutive acute ischemic stroke patients from 6 hospitals in the Chinese IntraCranial AtheroSclerosis Study. We evaluated the number and location of MBs, severity of lacune and leukoaraiosis (LA), and etiologic subtype of ischemic stroke. Multivariable logistic regression was used to analyze risk factors of MBs in different brain regions., Results: Among 696 acute ischemic stroke patients, 162 patients (23.3%) had MBs. Of them, 62 patients had strictly deep brain MBs, 49 patients had strictly lobar MBs. There was a significant correlation between the number of MBs, the number of lacune, and the severity of LA (P < .0001). In multivariable logistic regression analysis, both strictly deep and strictly lobar brain, MBs were significantly associated with history of cerebral hemorrhage (P = .037 and P = .026, respectively), presence of lacune (P = .004 and P = .032, respectively), and severe LA (P = .002 and P = .008, respectively). However, MBs in strictly deep regions were significantly associated with higher mean arterial pressure (P = .030), and those in strictly lobar brain regions were significantly associated with older age (P = .023)., Conclusions: The risk factors of MBs in strictly deep or lobar regions differ modestly, which may be related to heterogeneous vascular pathologic changes., (Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.)

Background and Purpose: Few studies have reported on the risk factors of dilated Virchow-Robin Spaces (dVRS) in large samples of ischemic stroke patients. Little evidence exists regarding the relationship between dVRS and etiologic subtype of ischemic stroke or lacune. We aimed to investigate the risk factors associated with the severity of dVRS in a large sample of ischemic stroke patients., Methods: We consecutively enrolled 1,090 patients who experienced an ischemic stroke within the past seven days and underwent a 3.0 T MRI scan in the Chinese IntraCranial AtheroSclerosis Study (ICAS). Clinical data and cranial MRI information of patients included age, sex, vascular risk factors, dVRS, leukoaraiosis, lacune, and etiologic subtype of ischemic stroke. Analyses were performed regarding the risk factors associated with the severity of dVRS by univariate analysis and multivariable ordinal logistic regression analysis., Results: Through multivariable ordinal logistic regression analysis, age, the severity of leukoaraiosis, lacune, admission National Institutes of Health Stroke Scale (NIHSS) ≤3, and the severity of dVRS in the white matter (WM) and hippocampus (Hip) were correlated with the severity of dVRS in basal ganglia (BG); male, history of hypertension, admission NIHSS ≤3, and the severity of dVRS in BG and Hip were correlated with the severity of dVRS in WM; female, the severity of leukoaraiosis, admission NIHSS >3, small artery occlusion subtype of ischemic stroke, and the severity of dVRS in BG and WM were correlated with the severity of dVRS in Hip., Conclusion: dVRS is an indicator of cerebral small vessel diseases such as leukoaraiosis and lacune. However, the risk factors of dVRS differ in various brain regions.

Background and Purpose: Our previous study found that cortical gray matter (cGM) volume predicted vascular cognitive impairment independent of age-related white matter changes (WMC). We aimed to investigate predictors for cGM volume in ischemic stroke patients with confluent WMC., Methods: One-hundred post-stroke patients with confluent WMC were recruited into the study. All volumetric measures were standardized by intracranial volume as volume ratio. Univariate analyses and multivariate linear regression models were used to test relationship of cGM volume with basic demography, vascular risk factors, APOE status, WMC volume (periventricular and deep WMC), infarct measures (volume, number and location) and microbleed (number, presence and location)., Results: After controlling for significant variables in the univariate analyses, multivariate linear regression models found that old age (β=-0.288, p=0.001), low triglyceride (β=0.194, p=0.027), periventricular WMC (PVWMC) (β=-0.392, p<0.001) and presence of thalamic microbleed (β=-0.197, p=0.041) were independently predictive of less cGM volume ratio., Conclusions: Age, PVWMC and left thalamic microbleed predict less cGM volume., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Background and Purpose: Computed tomography angiography is an accurate noninvasive method to diagnose intracranial steno-occlusive disease (ICAD) at initial presentation for stroke. We aimed to identify features of computed tomography angiography associated with unfavorable outcome., Methods: We identified patients with ICAD in the Screening Technology and Outcomes Project in Stroke Study, a prospective imaging-based study of stroke outcomes, in consecutive patients with ischemic stroke or transient ischemic attack (TIA) presenting to 2 academic medical centers. All patients underwent computed tomography angiography, which were graded by 2 neuroradiologists independently. Univariate and multiple logistic regression was used to evaluate predictors of favorable outcome at 6 months, defined as a modified Rankin Scale ≤ 2., Results: Among 539 patients that met study entry criteria, ICAD was identified in 212 patients (39%); 116 patients (22%) had concurrent extraintracranial lesions, and 66 patients (12%) had multiple sites of ICAD. Patients with ICAD had more severe stroke (median National Institutes of Health Stroke Scale, 9 versus 3; P<0.001), worse outcomes at 6 months (modified Rankin Scale, 0-2; 57% versus 73%; P<0.001), and higher mortality (18% versus 8%; P=0.001). In the multivariate model, age (odds ratio [OR], 0.75 per decade; 95% confidence interval [CI], 0.65-0.87), female sex (OR, 0.49; 95% CI, 0.32-0.73), multiple sites of ICAD (OR, 0.53; 95% CI, 0.29-0.97), complete occlusion (OR, 0.42; 95% CI, 0.25-0.72), and concurrent extraintracranial lesions (OR, 0.51; 95% CI, 0.31-0.84) negatively predicted favorable outcome., Conclusions: Findings of multiple sites of ICAD from computed tomography angiography, concurrent extraintracranial lesions, and complete occlusion are independent predictors of unfavorable outcome at 6 months.

Background: Although patients harboring confluent white matter hyperintensities (WMH) are at high risk of cognitive decline, this risk varies among individuals. We investigated the predictors for cognitive decline in stroke patients with confluent WMH., Methods: We followed up 100 stroke patients with confluent WMH who were participants of the VITAmins TO Prevent Stroke study for 2 years. We investigated the association between clinical features, apolipoprotein E status, imaging measures (infarcts, microbleeds, volumes of WMH, cortical gray matter [cGM], lateral ventricles, and hippocampi), and B vitamins with changes in cognitive measures (clinical dementia rating scale, Mini-Mental State Examination, Mattis dementia rating scale--initiation/perseveration subscale). We performed Pittsburgh compound B imaging among dementia converters., Results: Multivariate regression analysis showed that increase in clinical dementia rating scale grade was associated with cGM atrophy, absence of hyperlipidemia, and lower diastolic blood pressure at baseline. cGM atrophy and absence of hyperlipidemia were also associated with deterioration in Mini-Mental State Examination and Mattis dementia rating scale--initiation/perseveration subscale scores. Pittsburgh compound B retention typical of Alzheimer's disease was found only in 10% of dementia converters. Incident stroke and B vitamins were not associated with cognitive decline., Conclusions: Among stroke patients with confluent WMH, cGM atrophy and absence of hyperlipidemia are important predictors for cognitive decline. Significant cognitive decline can occur in the absence of incident stroke or Alzheimer's pathology., (Copyright © 2012 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.)

Objective: Cerebral microbleeds (CMBs) are common in stroke survivors. The clinical significance of CMBs in the development of suicidality (SI) following stroke is unknown. This study examined the association between SI and CMBs. The aim of the study reported here was to determine the relationship between CMBs and SI in ischemic stroke survivors., Methods: A cohort of 367 patients with acute ischemic stroke admitted to the stroke unit of a university-affiliated regional hospital in Hong Kong was recruited. SI was assessed with the geriatric mental state examination at three months following the subjects' index stroke. Depressive symptoms were assessed using the geriatric depression scale (GDS). A qualified psychiatrist administered the Chinese version of the Structured Clinical Interview for DSM-IV to diagnose depressive disorders. The presence and location of CMBs were evaluated with magnetic resonance imaging (MRI)., Results: Compared with the non-SI patients, SI patients were more likely to have CMBs in any brain region (36.6% vs. 20.2%, p = 0.017), specifically more lobar (29.3% vs. 13.5%, p = 0.008) and thalamic CMBs (19.5% vs. 7.5%, p = 0.018). Presence of CMBs (odds ratio was 2.5, p = 0.026) and lobar CMBs (odds ratio 2.6, p = 0.034) were independent predictors of SI in the multivariate analysis., Conclusions: The results suggest that lobar CMBs may play roles in the development of SI. The importance of CMBs in the pathogenesis of SI in stroke survivors warrants further investigation., (Copyright © 2012 The Academy of Psychosomatic Medicine. All rights reserved.)

Objective: Although cerebral small vessel disease (SVD) is closely associated with late life depression, patients with even severe SVD may have no depressive symptoms. We postulate that concurrent brain atrophy may also involve in the pathogenesis of depressive symptoms in SVD. We aimed to investigate the relevance of brain atrophy in predicting depressive symptoms among patients with severe SVD., Methods: We recruited 45 lacunar stroke patients who had diffuse white matter lesion (WML) and varying severity levels of depressive symptoms. We used a quantitative hybrid warping method to determine the volume of 99 brain regions for each patient. We assessed severity of depressive symptoms using the depression score of the hospital anxiety and depression scale (HADS-D). We first performed correlation analysis of each brain variable with the depression score. Significant variables were then entered separately into linear regression analysis to explore predictors of HADS-D, with adjustment of relevant clinical variables., Results: The mean age (SD) of the 45 participants was 74.6 (8.3) years. The mean HADS-D score was 3.5, with score ranging from 0 to 15. Variables that had a significant correlation coefficient with HADS-D were gender, hypertension, Oxford handicap scale, left inferior frontal gyrus, right subthalamic nucleus, left posterior limb of internal capsule, and right cerebellum. Regression analyses showed that only left inferior frontal gyrus atrophy (β = -0.354, p = 0.017) predicted HADS-D score after adjusted for other relevant clinical variables., Conclusion: Concurrent atrophy of left inferior frontal gyrus is associated with depressive symptoms in elderly patients with severe SVD., (Copyright © 2009 John Wiley & Sons, Ltd.)

Background and Purposes: Until now, limited data are available about the potential effect of coexisting small vessel disease (SVD) on the long-term outcome of stroke patients with intracranial large artery atherosclerosis (ILAA)., Methods: A prospective study was performed on 293 patients with symptomatic ILAA, who were divided into 4 groups (group I, single intracranial large artery atherosclerosis (SILAA) without SVD; group II, multiple intracranial large arteries atherosclerosis (MILAA) without SVD; group III, SILAA with SVD; group IV, MILAA with SVD) and followed up for recurrent stroke or death., Results: The 3-year cumulative risks of recurrent stroke were 18% for SILAA without SVD, 38% for MILAA without SVD, 21% for SILAA with SVD and 34% for MILAA with SVD. The 3-year cumulative risks of death were 6, 7, 20 and 22%, respectively. Compared with SILAA without SVD, more recurrent stroke occurred in MILAA without SVD (log-rank 3.83; p = 0.050) and MILAA with SVD (log-rank 7.79; p = 0.014), and the higher risk of death (log-rank 9.472; p = 0.002) was found in group MILAA with SVD. A Cox proportional-hazards regression model showed that MILAA with SVD may be a predictor of recurrent stroke (hazard ratio 2.001; 95% CI 1.108-3.934; p = 0.044), and a borderline predictor for death (hazard ratio 3.180; 95% CI 0.895-10.987; p = 0.073)., Conclusion: Coexisting SVD is very common and may predict poor outcome in stroke patients with symptomatic ILAA., (Copyright © 2010 S. Karger AG, Basel.)

Objective: Inflammatory endothelial activation mediated by intercellular adhesion molecule-1 (ICAM-1) plays a role in the pathogenesis of large- and small-vessel disease. We explored the association between soluble ICAM-1 (sICAM-1) and white matter lesion (WML) as a manifestation of cerebral small-vessel disease., Methods: One hundred and seventy-five elderly individuals aged >or= 60 without neurological deficits were studied. Subcortical deep white matter hyperintensity (SDWMH) and periventricular hyperintensity (PVH) were rated separately. Lesions in each category were then divided into three groups (grade 0-I, grade II, grade III) according to the Fazekas scale., Results: Plasma sICAM-1 levels were positively associated with grades of WML (for SDWMH: 297.4+/-135.6ng/mL in grade 0-I, 391.3+/-145.5ng/mL in grade II, and 450.2+/-232.9ng/mL in grade III, p<0.001; for PVH: 282.5+/-116.5ng/mL in grade 0-I, 402.3+/-160.4ng/mL in grade II, and 428.1+/-227.7ng/mL in grade III, p<0.001). Multivariate analysis showed higher sICAM-1 levels, age and hypertension were the independent risk factors associated with the presence and severity of WML. More than 4-fold increased risk of WML was observed in patients with the highest quartile of sICAM-1 (all WML OR=4.694, 95% CI: 1.805-12.204; moderate WML OR=4.618, 95% CI: 1.543-13.825; severe WML OR=4.893, 95% CI: 1.236-19.368)., Conclusion: Increased plasma sICAM-1 suggests inflammatory process may be involved in the pathogenesis of WML.

Objective: In ictal scalp electroencephalogram (EEG) the presence of artefacts and the wide ranging patterns of discharges are hurdles to good diagnostic accuracy. Quantitative EEG aids the lateralization and/or localization process of epileptiform activity., Methods: Twelve patients achieving Engel Class I/IIa outcome following temporal lobe surgery (1 year) were selected with approximately 1-3 ictal EEGs analyzed/patient. The EEG signals were denoised with discrete wavelet transform (DWT), followed by computing the normalized absolute slopes and spatial interpolation of scalp topography associated to detection of local maxima. For localization, the region with the highest normalized absolute slopes at the time when epileptiform activities were registered (>2.5 times standard deviation) was designated as the region of onset. For lateralization, the cerebral hemisphere registering the first appearance of normalized absolute slopes >2.5 times the standard deviation was designated as the side of onset. As comparison, all the EEG episodes were reviewed by two neurologists blinded to clinical information to determine the localization and lateralization of seizure onset by visual analysis., Results: 16/25 seizures (64%) were correctly localized by the visual method and 21/25 seizures (84%) by the quantitative EEG method. 12/25 seizures (48%) were correctly lateralized by the visual method and 23/25 seizures (92%) by the quantitative EEG method. The McNemar test showed p=0.15 for localization and p=0.0026 for lateralization when comparing the two methods., Conclusions: The quantitative EEG method yielded significantly more seizure episodes that were correctly lateralized and there was a trend towards more correctly localized seizures., Significance: Coupling DWT with the absolute slope method helps clinicians achieve a better EEG diagnostic accuracy.

Objectives: Small subcortical infarcts (SSIs) can result from small vessel disease (SVD) and intracranial and extracranial large artery disease (LAD). No study has explored poststroke depression (PSD) in different etiological types of SSIs., Methods: Patients with SSIs resulting from LAD and SVD were included in the study. Poststroke depression was evaluated with the 15-item version of the geriatric depression scale (GDS) 3 months after stroke., Results: Of the 127 patients with SSIs, 44 had LAD and 83 had SVD. The LAD group had a significantly higher mean GDS score and higher frequency of PSD (p<0.05). The etiological type LAD was a significant independent risk factor for PSD., Conclusion: PSD is more common in patients with SSIs resulting from LAD. This suggests that cerebral blood perfusion may play an important role in the development of PSD.

Background: Although confluent white matter lesion (WML) is associated with cognitive impairment, the mechanism explaining this association is controversial. We aimed to investigate comprehensively the MRI predictors of cognitive impairment in confluent WML., Methods: Among 45 lacunar stroke patients who had confluent WML, we evaluated the association of executive function [Mattis Dementia Rating Scale - Initiation/Perseveration subscale (MDRS I/P)] and global cognition [Mini-Mental State Examination (MMSE)] with the volume of WML, measures of lacunes and microbleeds, and the volumes of 99 other specific brain regions., Results: Regression analyses showed that WML volume predicted performance on the MDRS I/P (beta = -0.34, p = 0.016) independent of age. Volumes of cortical gray matter (cGM; beta = 0.41, p = 0.003), the lateral fronto-orbital gyrus (beta = 0.38, p = 0.01), superior frontal gyrus (beta = 0.29, p = 0.04), lateral ventricle (beta = -0.30, p = 0.04), and posterior limb of the internal capsule (beta = 0.43, p = 0.002) predicted MDRS I/P performance independent of WML volume. Volumes of cGM, and the lateral fronto-orbital gyrus predicted MMSE performance as well., Conclusion: Atrophy along the frontosubcortical pathways and cGM predict cognition in confluent WML independent of WML volume., ((c) 2007 S. Karger AG, Basel.)

Background: Hyperhomocysteinemia is associated with cerebral small vessel disease (SVD). We examined the relationship between homocysteine and 1) volumetric measure of white matter change (WMC), 2) silent brain infarcts, 3) cerebral atrophy on MRI and 4) cognition on a consecutive cohort of patients with stroke associated with SVD., Subjects and Methods: Fifty-seven patients consecutively admitted to the Acute Stroke Unit in a university hospital due to stroke associated with SVD were recruited and assessed three months after the stroke. Non-fasting homocysteine was obtained. Using MRI, the number of infarcts, volume of WMC and cerebral atrophy were measured. General cognitive functions were assessed using the Mini Mental State Examination and Alzheimer's disease Assessment Scale. Mattis Dementia Rating Scale - Initiation/Perseveration subset was used to assess executive cognitive functions., Results: Hyperhomocysteinemia (> or = 14.88 micromol/L) significantly accounted for the volume of WMC on MRI in a multivariate stepwise regression model (adjusted R(2)=0.058, p <0.05) after adjustment for age and folate level. Patients in the highest quartile of WMC volume had significantly higher levels of homocysteine than those in lowest quartile (p <0.001). No significant relationship was found between homocysteine and silent brain infarcts, cerebral atrophy and performance on psychometric tests., Conclusion: Hyperhomocysteinemia is associated with volumetric measure of WMC among patients with SVD. The role of homocysteine in the development of silent brain infarcts and cerebral atrophy as previously reported cannot be ascertained in this study. No direct relationship was found between homocysteine and cognitive functions.

Microbleeds (MBs) detected by gradient-echo T2*-weighted MRI (GRE-T2*),white matter changes and lacunar infarcts may be regarded as manifestations of microangiopathy. The establishment of a quantitative relationship among them would further strengthen this hypothesis. We aimed to investigate the frequency and the number of MBs in patients hospitalized with lacunar infarcts and their quantitative relationship with the severity of white matter changes (WMC) and the number of old lacunar infarcts. We performed a hospital-based survey of patients with acute lacunar infarct. Eighty-two consecutive Chinese patients with acute lacunar infarcts on diffusion-weighted imaging were recruited in 2002. The number of MBs, number of old lacunar infarcts on T2-weighted imaging and the severity of WMC on MRI on admission were recorded. MBs were detected in 22 (27%) patients. The number of MBs ranged from 1 to 42 (mean 6.59, median 3). Advancing age and previous transient ischemic attacks or cerebrovascular accidents (TIA/CVA) were more common in patients with MBs than those without. There were significant correlations among the number of MBs, extent of WMC and number of lacunar infarcts: lacunar infarcts and MBs (r = 0.297, p = 0.007); lacunar infarct and WMC (r = 0.331, p = 0.002); WMC and MBs (r = 0.522, p < 0.0001). In conclusion, linear associations exist among MBs, WMC and lacunar infarcts. Our results suggest that all three may have a shared pathogenesis such as advanced microangiopathy.

Background and Purpose: A new simple visual rating scale can be used in magnetic resonance imaging (MRI) to grade the severity of white matter changes (WMC). The authors sought to study the interobserver variability and the validity of this visual rating scale against a computer-aided quantitative method in measuring WMC., Methods: The authors examined 220 magnetic resonance images from stroke-free patients with traditional risk factors for atherosclerosis and middle cerebral artery stenosis who were participants in a clinical trial requiring MRI examination. The severity of WMC was graded from 0 (no WMC) to 3 (severe WMC). For the quantitative assessment of WMC, the volume of WMC were measured with a computer-aided, automated segmentation method. The interobserver variability was also determined., Results: The mean volumes were significantly different among the different groups, which were scored 1, 2, and 3 (1324.59, 6475.48, and 25,440.05 mm3, respectively; 1-way analysis of variance, P < .001). Interobserver variability for grading WMC was good in different locations of the brain. Excellent results were found in the frontal lobe (kappa = 0.829) and the parietal-occipital lobe (kappa = 0.646), whereas poor results were found in the basal ganglia (kappa = 0.391). There was perfect agreement between the 2 observers in 89.1% for the frontal lobe and 77.0% for the parietal-occipital lobe., Conclusions: The results suggest that this simple visual rating scale is a valid and reliable method for grading WMC in the lobar region but not in the basal ganglion.

BackgroundIntracranial arterial stenosis (ICAS) is the predominant cause of ischemic stroke and transient ischemic attack in Asia. Change of signal intensities (SI) across an ICAS on magnetic resonance angiography (MRA) may reflect its hemodynamic severity.MethodsIn-patients with a symptomatic single ICAS detected on 3D time-of-flight MRA were recruited from 2 hospitals. Baseline and 1-year follow-up data were collected. Signal intensity ratio (SIR) [ =  (mean post-stenotic SI -mean background SI)/(mean pre-stenotic SI - mean background SI)] was evaluated on baseline MRA to represent change of SIs across an ICAS. Acute infarct volume was measured on baseline diffusion-weighted images (DWI). Relationships between SIR and baseline characteristics as well as 1y outcomes were evaluated.ResultsThirty-six subjects (86.1% males, mean age 55.0) were recruited. Overall, mean SIR was 0.84±0.23. Mean SIRs were not significantly different between the 23 (63.9%) anatomically severe stenoses and the 13 (36.1%) anatomically moderate stenoses (0.80±0.23 versus 0.92±0.21, p = 0.126). SIR was significantly, linearly and negatively correlated to acute infarct volume on DWI (Spearman correlation coefficient -0.471, p = 0.011). Two patients (5.6%) had recurrent ischemic strokes at 1y, not related to SIR values.ConclusionsChange of signal intensities across an ICAS on MRA may reflect its hemodynamic and functional severity. Future studies are warranted to further verify the relationships between this index and prognosis of patients with symptomatic ICAS.

Purpose: Intracranial artery calcification (IAC) has been demonstrated to be correlated with ischemic stroke, cognitive decline, and other vascular events by accumulating evidences from both Western and Asian populations. The proposed study aimed to investigate its potential mechanisms by evaluating the blood flow velocity and pulsatility index (PI) of cerebral arteries.Methods: Consecutive ischemic stroke patients admitted to the Prince of Wales Hospital were recruited after excluding those with atrial fibrillation or poor temporal window. Quantitative measurements of IAC severity were assessed on brain CT scans. Transcranial Doppler (TCD) ultrasonography was performed to evaluate the blood flow velocity of the middle cerebral artery (MCA) and vertebral-basilar artery (VBA).Results: In total, 318 patients were analyzed. Spearman’s correlation analysis demonstrated both high MCA systolic flow velocity and high MCA PI were correlated with IAC Agatston score, p < 0.001 individually. Similar correlation was also found between IAC Agatston score and high VBA velocity/high VBA PI, p ≤ 0.001 individually. Multiple logistic regression analysis showed IAC Agatston score was an independent risk factor for high MCA velocity (OR 1.533; 95% CI 1.235-1.903), high VBA velocity (OR 1.964; 95% CI 1.381-2.794), and high VBA PI (OR 1.200; 95% CI 1.016-1.418), respectively.Conclusion: Heavier IAC might cause generalized artery flow velocity changes and increased pulsatility index, which may indicate high resistance within cerebrovasculature. [ABSTRACT FROM AUTHOR]

Background: Collateral pathways are important in maintaining adequate cerebral blood flow in patients with carotid stenosis. We aimed to evaluate the hemodynamic patterns in relation to carotid stenosis in acute stroke patients.Methods: Consecutive 586 stroke patients in a hospital based cohort were included in the present study. Carotid duplex was performed to identify patients with absolute minimal diameter reductions of 50% or greater in their internal carotid arteries (ICAs). Color velocity imaging quantification ultrasound (CVIQ) was used to measure extracranial arterial blood flow volume (BFV) in bilateral common carotid arteries (CCAs) and bilateral vertebral arteries (VAs). The absolute values of BFV and the ratios were compared between patients with and without ICA stenosis.Results: Among 586 acute ischemic stroke patients (mean age: 67.5 ± 12.4y), ICA stenosis was detected in 112 patients (19.1%), including unilateral ICA stenosis in 81 patients (13.8%) and bilateral ICA stenosis in 31 patients (5.3%). Among patients with unilateral ICA stenosis, the BFV in contralateral CCA was significantly higher than that in ipsilateral CCA (325.5 ± 99.8 mL/min vs. 242.2 ± 112.2 mL/min, P < 0.001). Among patients with bilateral ICA stenosis, the sum of BFV in bilateral VAs accounted for 22% of the whole cerebral blood flow, which was significantly higher than that in those without ICA stenosis (14.8%, P < 0.001) or with unilateral ICA stenosis (16.9%, P = 0.007).Conclusions: In patients with unilateral carotid stenosis, contralateral carotid blood flow increases to compensate decreased blood flow, while posterior circulation may compensate for the decreased brain perfusion in those with bilateral carotid stenosis. [ABSTRACT FROM AUTHOR]

Background/Aims: This study aimed to determine the clinical and neuroimaging correlates of the presence of neuropsychiatric symptoms in stroke patients with age-related confluent white matter hyperintensities (WMH). Methods: The Neuropsychiatric Inventory was utilized to detect the presence of 12 symptoms. Multivariate logistic regression models were used to identify clinical and neuroimaging correlates of the presence of symptoms. Results: Seventy-seven stroke patients (mean WMH volume: 39.5 cm3) were recruited. Thirty patients (39%) had ≥1 neuropsychiatric symptom. Poor executive function was associated with the presence of any symptoms and symptoms other than depression. More severe left frontal WMH was associated with depression. Conclusion: Executive dysfunction and left frontal WMH are correlated with neuropsychiatric symptoms in these patients. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]