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Background: Posterior reversible encephalopathy syndrome (PRES) is characterized by cerebral blood flow dysregulation and the blood-brain barrier (BBB) disruption. While renal insufficiency has been considered a factor in BBB fragility, the relationship between renal insufficiency and the PRES lesions volume remains unclear., Methods: This observational study was performed retrospectively. PRES patients were categorized into two groups with renal insufficiency, defined as an estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73m 2 on the day of symptom occurrence. Lesion volume was measured using fluid-attenuated inversion recovery (FLAIR) imaging, and the brain was divided into nine regions. The volume of the parietal-occipital-temporal lobe was considered typical, while the other six regions were labeled as atypical., Results: The study included 200 patients, of whom 94 (47%) had renal insufficiency. Patients with renal insufficiency had a larger lesion volume (144.7 ± 125.2 cc) compared to those without renal insufficiency (110.5 ± 93.2 cc; p = 0.032); particularly in the atypical lesions volume (49.2 ± 65.0 vs. 29.2 ± 44.3 cc; p = 0.013). However, there was no difference in the reversibility of the lesions (35.2 ± 67.5 vs. 18.8 ± 33.4 cc; p = 0.129). Multiple regression analysis revealed that decreases in eGFR (β = -0.34, 95% CI -0.62-0.05, p = 0.020) were positively associated with total lesion volume., Conclusion: Our findings suggest that PRES patients with renal insufficiency experience more severe lesion volumes, likely due to the atypical brain regions involvement. The lesions involving atypical regions may have a similar pathophysiology to typical lesions, as the PRES lesions reversibility was found to be similar between individuals with and without renal insufficiency., (© 2024. Fondazione Società Italiana di Neurologia.)

Objectives: To investigate whether clinical condition, imaging session, and locations affect repeatability of amide proton transfer-weighted (APTw) magnetic resonance imaging (MRI) in the brain., Materials and Methods: Three APTw MRI data sets were acquired, involving two intrasession scans and one intersession scan for 19 healthy, 15 glioma, and 12 acute stroke adult participants (mean age 53.8, 54.6, and 68.5, respectively) on a 3T MR scanner. The mean APTw signals from five locations in healthy brain (supratentorial and infratentorial locations) and from entire tumor and stroke lesions (supratentorial location) were calculated. The within-subject coefficient of variation (wCV) and intraclass correlation coefficient (ICC) were calculated for each clinical conditions, image sessions, and anatomic locations. Differences in APTw signals between sessions were analyzed using repeated-measures analysis of variance., Results: The ICC and wCV were 0.96 (95% confidence interval [CI], 0.91-0.99) and 16.1 (12.6-21.3) in glioma, 0.93 (0.82-0.98) and 15.0 (11.4-20.6) in stroke, and 0.84 (0.72-0.91) and 34.0 (28.7-41.0) in healthy brain. There were no significant differences in APTw signal between three sessions, irrespective of disease condition and location. The ICC and wCV were 0.85 (0.68-0.94) and 27.4 (21.8-35.6) in supratentorial, and 0.44 (- 0.18 to 0.76) and 32.7 (25.9 to 42.9) in infratentorial locations. There were significant differences in APTw signal between supra- (mean, 0.49%; 95% CI, 0.38-0.61) and infratentorial locations (1.09%, 0.98-1.20; p < 0.001)., Conclusion: The repeatability of APTw signal was excellent in supratentorial locations, while it was poor in infratentorial locations due to severe B0 inhomogeneity and susceptibility which affects MTR asymmetry., Key Points: • In supratentorial locations, APTw MRI showed excellent intrasession and intersession repeatability in brains of healthy controls and patients with glioma, as well as in stroke-affected regions. • APTw MRI showed excellent repeatability in supratentorial locations, but poor repeatability in infratentorial locations. • Considering poor repeatability in the infratentorial locations, the use of APTw MRI in longitudinal assessment in infratentorial locations is not indicated.

Objectives: To determine whether fast scanned MRI using a 1.5-T scanner is a reliable method for the detection and characterization of acute ischemic stroke in comparison with conventional MRI., Methods: From May 2015 to June 2016, 862 patients (FLAIR, n = 482; GRE, n = 380; MRA, n = 190) were prospectively enrolled in the study, with informed consent and under institutional review board approval. The patients underwent both fast (EPI-FLAIR, ETL-FLAIR, TR-FLAIR, EPI-GRE, parallel-GRE, fast CE-MRA) and conventional MRI (FLAIR, GRE, time-of-flight MRA, fast CE-MRA). Two neuroradiologists independently assessed agreements in acute and chronic ischemic hyperintensity, hyperintense vessels (FLAIR), microbleeds, susceptibility vessel signs, hemorrhagic transformation (GRE), stenosis (MRA), and image quality (all MRI), between fast and conventional MRI. Agreements between fast and conventional MRI were evaluated by generalized estimating equations. Z-scores were used for comparisons of the percentage agreement among fast FLAIR sequences and fast GRE sequences and between conventional and fast MRA., Results: Agreements of more than 80% were achieved between fast and conventional MRI (ETL-FLAIR, 96%; TR-FLAIR, 97%; EPI-GRE, 96%; parallel-GRE, 98%; fast CE-MRA, 86%). ETL- and TR-FLAIR were significantly superior to EPI-FLAIR in the detection of acute ischemic hyperintensity and hyperintense vessels, while parallel-GRE was significantly superior to EPI-GRE in the detection of susceptibility vessel sign (p value < 0.05 for all). There were no significant differences in the other scores and image qualities (p value > 0.05)., Conclusions: Fast MRI at 1.5 T is a reliable method for the detection and characterization of acute ischemic stroke in comparison with conventional MRI., Key Points: • Fast MRI at 1.5 T may achieve a high intermethod reliability in the detection and characterization of acute ischemic stroke with a reduction in scan time in comparison with conventional MRI.

Purpose To determine whether magnetic resonance (MR) imaging by using two-dimensional spatially selective radiofrequency (RF) excitation pulses (zoomed MR imaging) is a reliable method for the diagnosis of intracranial artery steno-occlusion compared with full-field-of-view (FOV) MR imaging. Materials and Methods The institutional review board approved this retrospective study and informed consent was waived. From December 2014 to August 2015, 88 patients who underwent both full-FOV MR imaging and zoomed MR imaging for further evaluation of intracranial artery steno-occlusion at prior luminal evaluation were included. Two neuroradiologists independently diagnosed the diseases (atherosclerosis, dissection, moyamoya disease, vasculitis, undetermined diagnosis, and no vascular pathologic condition) based on both clinical information and MR imaging features and assessed diagnosis-related parameters (diameter, length, eccentricity index, eccentricity, signal intensity ratio, vessel wall hemorrhage, and the total number of lesions), as well as image quality parameters (signal-to-noise ratio and image quality scale) with full-FOV MR imaging and zoomed MR imaging. Parametric measurements were compared between full-FOV MR imaging and zoomed MR imaging by using paired t test and McNemar test. The criterion for intermethod reliability was that the upper limit of the 95% confidence interval (CI) in the difference of agreement was less than 10% based on a noninferiority test. Results The pooled agreement for diagnosing the disease between full-FOV MR imaging and zoomed MR imaging was 93% (164 of 176 lesions). The difference of agreement was 2.84% (one-sided 95% CI: -0.49%, 6.17%). The diagnosis-related parameters were not significantly different between both methods (all P > .05), with good to excellent agreement (both intraclass correlation coefficient and κ value ≥0.61). However, full-FOV MR imaging had better image quality parameters than zoomed MR imaging, including precontrast signal-to-noise ratio and image quality scale (both P < .05). Conclusion Zoomed MR imaging is a reliable method for the diagnosis of intracranial artery steno-occlusion compared with full-FOV MR imaging. © RSNA, 2017 Online supplemental material is available for this article. An earlier incorrect version of this article appeared online. This article was corrected on May 2, 2017.

Background and Purpose: Quantitative measurements, as well as qualitative characterizations, of the vessel walls of the small intracranial arteries became clinically available and reliable beyond the resolution limit of 1.5 T high-resolution magnetic resonance imaging (HR-MRI) with the development of 3 T HR-MRI. We present the quantitative dissection findings of spontaneous and unruptured acute intracranial artery dissection (SID) using 3 T HR-MRI and investigate the differences between each cerebral artery., Methods: Twenty-eight lesions (anterior cerebral artery = 6; middle cerebral artery = 4; vertebral artery = 18) from 26 patients (17 male and 9 female patients; mean age = 47 years; age range = 32-74 years) with presumptive diagnoses of SID were included. The diagnosis was determined based on the clinical features, findings on luminal angiography (such as digital subtraction angiography, computed tomography, or magnetic resonance angiography), and HR-MRI. HR-MRI was performed within one month from onset. The neuroimaging indices (maximal outer diameter and area, remodeling index and modified remodeling index, and wall thickness and wall area index) of aneurysmal dilatation and the signal intensities of the intramural hematomas were rated using HR-MRI. The results were compared between each cerebral artery., Results: The maximal outer diameter and area, remodeling index and modified remodeling index, and wall thickness index and length were significantly different between anterior and posterior circulation (P < .05). The mean relative signal intensities of the intramural hematoma showed consistent values, regardless of the cerebral arteries, without significant difference., Conclusions: Neuroimaging indices of aneurysmal dilatation may be adjunctive indicators in the evaluation of SID., (Copyright © 2016 by the American Society of Neuroimaging.)

Objective: To test whether a silent new ischemic lesion (SNIL) on MRI after stroke predicted future recurrent ischemic stroke or vascular events., Methods: In this prospective study, we analyzed data from patients presenting with acute ischemic stroke who underwent MRI <24 hours and 5 and 30 days after symptom onset. The presence of a SNIL at 5 (5D-SNIL) and 30 (30D-SNIL) days was determined on diffusion-weighted and fluid-attenuated inversion recovery images. Patients were contacted every 3-6 months to identify recurrent clinical events. The log-rank test and Cox proportional hazard model were used to estimate the hazard ratio of recurrent ischemic stroke and composites of recurrent ischemic stroke, transient ischemic attack, acute coronary syndrome, and vascular death., Results: The 5D- and 30D-SNILs were found in 24.4% (66/270) and 7.4% (19/256) of patients. During the 5-year follow-up, clinical events were observed in 42 patients (15.6%). The 5D- and 30D-SNIL independently predicted recurrent ischemic stroke (hazard ratio [95% confidence interval] 2.9 [1.3-6.4] and 9.6 [4.1-22.1], respectively) and composite vascular events (2.4 [1.3-4.5] and 6.1 [3.1-12.4], respectively)., Conclusions: Patients with a SNIL within the first few weeks after index stroke have an increased risk of recurrent ischemic stroke or vascular events. The presence of a SNIL on MRI could serve as a surrogate endpoint for clinical recurrence in secondary prevention clinical trials., (© 2015 American Academy of Neurology.)

Background: Although high-resolution magnetic resonance imaging (HR-MRI) has been used as a strong imaging method for diagnosing intracranial vertebral artery dissection (IVAD), the diagnosis is sometimes challenging because a dissection has geometric changes in the natural course. The radiologic features may change or disappear over time, which makes the diagnosis confusing. Our study was to present radiological findings according to the stages in spontaneous and unruptured, IVAD on 3T HR-MRI and to guide the age estimation of IVAD with the distinguishing findings according to the stages., Methods: From January 2011 to July 2014, the 41 vertebral arteries (M:F = 18:12; age range 32-67 years) were retrospectively enrolled. Spontaneous, unruptured IVAD was diagnosed if it had a clear onset based on clinical and radiological findings. The stages were classified as acute (0-3 days), early subacute (3-10 days), late subacute (10-60 days) and chronic stage (>60 days; recovery and non-recovery groups) according to the time intervals from symptom onset, based on the prior published studies. HR-MR findings were assessed and compared in the intimal flap, double lumen, aneurysmal dilatation (maximal outer diameter, maximal wall thickness, wall thickness index and remodeling index), intramural hematoma (relative signal intensity) and vessel wall enhancement according to the stages with qualitative and quantitative methods. Two radiologists analyzed the HR-MR findings with consensus reading., Results: IVAD was classified into acute (n = 6), early subacute (n = 8), late subacute (n = 16) and chronic (n = 11) stages. HR-MR dissection findings such as intimal flap, double lumen, aneurysmal dilatation and intramural hematoma significantly decreased from the earlier stages to the chronic stage (p < 0.05). The quantitative indices in aneurysmal dilatation and the relative signal intensity of intramural hematoma showed significant higher values in the earlier stages followed by a significant decrease in the chronic stage recovery group (p < 0.05). The degree of vessel wall enhancement was higher in the earlier stage and decreased in the chronic stage (p < 0.05), but mild vessel wall enhancement was identified 900 days after symptom onset., Conclusion: The 3T HR-MRI reveals the vessel wall characteristics and provides distinguishing findings between earlier stages and the chronic stage in spontaneous and unruptured IVAD. Characterization of these radiological findings according to stages may assist with the age estimation of the dissection and may help to understand IVAD as a whole., (© 2016 S. Karger AG, Basel.)

Background and Purpose: Diagnosis of intracranial artery atherosclerosis remains often uncertain. The high-resolution magnetic resonance imaging (HR-MRI) enables vessel wall assessment for more precise diagnoses. The aim of the present study was to investigate the etiologies of middle cerebral artery steno-occlusive disease in young adult patients with few atherosclerotic risk factors using HR-MRI., Methods: We prospectively studied patients who visited a tertiary hospital in Seoul, Korea, and had (1) unilateral middle cerebral artery disease (≥50% stenosis or occlusion), (2) were ≤55 years old and had no or minimal (≤1) atherosclerotic risk factors. We excluded patients with a confirmed diagnosis of Moyamoya disease, vasculitis, or dissection and those having emboligenic sources. A presumptive diagnosis was made based on HR-MRI findings, and patients were categorized as HR-athero (atherosclerotic disease), HR-MMD (Moyamoya disease), HR-dissection, or HR-vasculitis., Results: Among 95 patients analyzed, 26 (27.4%) had HR-athero who were more often male (P=0.004), smokers (P=0.018), and had focal stenosis (P=0.003) than others.As compared with the HR-athero patients, 29 HR-MMD patients were more often female (P<0.001) and more often had occlusive lesions (P=0.001) and nonfocal stenosis (P<0.001). The 22 HR-dissection patients tended to have hypertension less often, and the 13 HR-vasculitis patients were younger (P=0.004) and tended to have nonfocal stenosis. [corrected]., Conclusions: In our cohort of young patients with minimal risk factors, atherosclerosis seems to be an uncommon pathology of middle cerebral artery stenosis. HR-MRI aids us to make a more reliable diagnosis., (© 2015 American Heart Association, Inc.)

Background: Ischemic lesions dynamically evolve during the acute phase of stroke. Although the ischemic lesion volume has been considered as a predictor of clinical outcome, it is still controversial whether early changes in ischemic lesion have prognostic information in addition to clinical variables. We hypothesized that early infarct growth on diffusion-weighted imaging (DWI) might be independently associated with long-term outcome in acute ischemic stroke patients., Methods: This was a prospective study for acute ischemic stroke patients admitted to the Stroke Unit of Asan Medical Center. The patients underwent DWI at baseline (within 24h) and subsequently at 5 days after stroke onset. Early infarct growth was defined as the absolute difference between follow-up and baseline infarct volumes. Poor outcome was a modified Rankin Scale (mRS) at 3 months of 2-6 or 3-6. The association between infarct growth on DWI and clinical outcome was explored using multivariate analysis adjusting for demographics, risk factors for stroke, and other clinical variables. The cut-off values of early infarct growth predicting long-term outcomes were estimated using receiver operating characteristic analysis., Results: Of 409 patients enrolled, 345 (84.4%) showed any infarct growth (median, 0.63 cm(3); interquartile range [IQR], 0.11-6.33 cm(3); mean ± standard deviation, 9.55 ± 25.54 cm(3)). At the 3-month follow-up, the good outcomes were observed in 217 patients (53.1%) for mRS 0-1 and 303 patients (74.1%) for mRS 0-2. The larger infarct growth was associated with poor clinical outcome (for mRS 2-6, 0.29 cm(3) [IQR 0.04-2.19] vs. 2.16 cm(3) [IQR 0.26-17.68], p<0.001; and for mRS 3-6, 0.39 cm(3) [IQR 0.05-3.25] vs. 7.36 cm(3) [IQR 0.57-26.48], p<0.001). After adjusting age, diabetes, baseline National Institutes of Health Stroke Scale, and baseline infarct volume by multivariate logistic regression analysis, infarct growth was an independent predictor of poor clinical outcomes (for mRS 2-6, odds ratio [OR], 1.03, 95% confidence interval [CI], 1.004-1.06, p=0.03; and for mRS 3-6, OR, 1.03, 95% CI, 1.01-1.05, p=0.01). The cut-off values of infarct growth discriminating between good and poor outcomes were 0.99 cm(3) for mRS 0-1 vs. 2-6 (area under curve, 0.685; P<0.001) and 8.86 cm(3) for mRS 0-2 vs. 3-6 (area under curve, 0.736; P<0.001)., Conclusions: Our present study findings show that infarct growth within a week of onset independently predicts 3-month clinical outcomes. This suggests that short-term changes in infarct volume may serve as a surrogate marker of long-term clinical outcomes after ischemic stroke., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Background: The clinical diagnosis of transient ischemic attack is highly subjective, and the risk prediction after transient ischemic attack using the clinical parameters still remains unsatisfactory., Aims: We aimed to investigate the diagnostic and prognostic value of multimodal magnetic resonance imaging in transient ischemic attack patients., Methods: We prospectively performed diffusion-weighted imaging, perfusion-weighted imaging, and intracranial and extracranial magnetic resonance angiogram within 72 h of symptom onset in 162 transient ischemic attack patients defined by the classical time-based definition. Follow-up diffusion-weighted imaging was obtained three-days later in patients who did not exhibit lesions on the initial diffusion-weighted imaging. The occurrence of clinical events (transient ischemic attack or stroke) three-months after the initial transient ischemic attack was recorded, and the ABCD2 and ABCD3-I scores were calculated. The clinical and imaging parameters were compared between patients with and without initial diffusion-weighted imaging lesion, clinical events, and follow-up diffusion-weighted imaging lesions., Results: Abnormalities were present on diffusion-weighted imaging, perfusion-weighted imaging, and magnetic resonance angiogram in 38·9%, 44·1%, and 51·9% of patients, respectively. Diffusion-weighted imaging plus perfusion-weighted imaging explained 64·8%, and the addition of magnetic resonance angiogram explained 74% of the transient ischemic attack symptoms. The initial diffusion-weighted imaging positivity was associated with longer time from symptom onset to magnetic resonance imaging examination (odds ratio, 1·039; 95% confidence interval, 1·008-1·071; P=0·013). On follow-up diffusion-weighted imaging, new lesions were found in 46·7% of the patients who initially showed normal diffusion-weighted imaging findings. Initial perfusion-weighted imaging abnormality predicted the appearance of follow-up diffusion-weighted imaging lesion (chi-square=7·774, P=0·005). During the three-months follow-up, 23 patients (14·2%) experienced subsequent transient ischemic attack (n=16) or stroke (n=7). Symptomatic magnetic resonance angiogram abnormality (odds ratio, 12·667; 95% confidence interval, 2·859-56·110; P=0·001) was the only independent factor associated with clinical events with a sensitivity of 91·3% and specificity of 54·7% (C statistics, 0·73). None with initially normal multimodal magnetic resonance imaging findings developed subsequent clinical events., Conclusions: Approximately three-quarter of transient ischemic attack is associated with multimodal magnetic resonance imaging abnormality. Initial perfusion-weighted imaging abnormality predicts newly developed diffusion-weighted imaging lesions, and symptomatic magnetic resonance angiogram abnormality seems to be the most important predictor for subsequent clinical events. Multimodal magnetic resonance imaging appears to be useful in assessing transient ischemic attack and predicting outcome in these patients., (© 2013 The Authors. International Journal of Stroke © 2013 World Stroke Organization.)

Background and Purpose: Single subcortical infarction (SSI) may be classified as proximal SSI (pSSI) or distal SSI (dSSI) according to its extension to the middle cerebral artery (MCA). We investigated the differences between pSSI and dSSI in terms of their clinical features, lesion size, and the frequency of MCA plaques detected by high-resolution MRI., Methods: Thirty-nine patients with SSI (20 pSSI and 19 dSSI) were prospectively enrolled who did not show relevant MCA disease on MR angiography. Lesion size, neurological status (initial National Institutes of Health Stroke Scale score and modified Rankin Scale at 3 months), and the presence and location (superior versus inferior) of high-resolution MRI-identified plaques were evaluated., Results: The frequencies of MCA plaques did not differ between patients with pSSI and those with dSSI (8 [40%] versus 12 [63.2%]; P=0.205); however, superiorly located plaques were significantly more common in patients with pSSI than in those with dSSI (6 [75%] versus 2 [16.7%]; P=0.019). Initial lesion volumes were larger (1.96±1.18 versus 1.11±1.11 mm(3); P=0.025), National Institutes of Health Stroke Scale scores were higher (5 [3-6.75] versus 3 [1-3] points; P=0.017), and microbleeds were fewer (1 [5%] versus 10 [52.6%]; P=0.001) in patients with pSSI than in those with dSSI. Three-month modified Rankin Scale scores were higher in patients with superior plaques than in those with inferior plaques., Conclusions: Compared with dSSI, pSSI is closely associated with large lesions, severe clinical symptoms, and superiorly located MCA plaques, suggesting that the location, rather than simple presence of plaques, determines the SSI location.

Background and Purpose: Unclear-onset strokes are generally excluded from time-based thrombolytic therapy. We examined the safety and feasibility of magnetic resonance imaging-based reperfusion therapy in unclear-onset stroke., Methods: This prospective, multicenter, single-arm study screened consecutive unclear-onset stroke patients within 6 hours of symptom detection. Patients with perfusion-diffusion mismatch>20% and negative or subtle fluid-attenuated inversion recovery changes were treated with intravenous tissue plasminogen activator, intra-arterial therapy, or a combination. The safety outcome was symptomatic intracranial hemorrhage within 48 hours after treatment. The primary efficacy outcome was a 3-month modified Rankin Scale score of 0 to 2. Controls were untreated unclear-onset stroke patients prospectively captured in stroke registries., Results: Of 430 unclear-onset stroke patients, 83 (19.3%) received reperfusion therapy (mean age, 67.5±10.4 years; males, 66.3%; median baseline National Institutes of Health Stroke Scale, 14). Symptomatic intracranial hemorrhage with any neurological decline developed in 5 patients (6.0%). Symptomatic intracranial hemorrhage with National Institutes of Health Stroke Scale worsening ≥4 developed in 3 patients (3.6%). Thirty-seven patients (44.6%) achieved modified Rankin Scale score of 0 to 2, and 24 (28.9%) had modified Rankin Scale score of 0 to 1. Female, baseline National Institutes of Health Stroke Scale score, no immediate or early recanalization, and more white blood cells were independent predictors of poor outcome. Compared with untreated controls, the treated group was significantly associated with good outcomes of modified Rankin Scale score of 0 to 2 after adjusting for age, sex, and baseline National Institutes of Health Stroke Scale in logistic regression analysis (odds ratio, 2.25; 95% CI, 1.14-4.49)., Conclusions: In unclear-onset stroke patients, magnetic resonance imaging-based reperfusion therapy was feasible and safe. Randomized controlled trials are warranted to confirm the benefit of reperfusion therapy for unclear-onset stroke.

Background and Purpose: Although MRI may provide much information on brain pathology to aid in patient selection for thrombolysis, the concern remains that MRI screening may increase time-to-treatment. We hypothesized that CT-plus-MRI screening might be a valuable time-efficient alternative for selection of patients requiring thrombolysis., Methods: We reviewed acute stroke patients who received intravenous tissue plasminogen activator (tPA) (with or without intra-arterial urokinase) initiated within 3 h of stroke between March 2004 and March 2007. MRI was the routine screening imaging employed until November 2005. Thereafter, CT-plus-MRI screening was performed; tPA of 0.6 mg/kg was infused intravenously after exclusion of hemorrhage by CT screening, and subsequently a further decision on thrombolysis (i.e., intravenous tPA of 0.3 mg/kg, or intra-arterial urokinase) was made after MRI screening. We compared times-to-treatment and clinical outcomes between MRI screening and CT-plus-MRI-screening groups, and identified factors associated with good clinical outcome (modified Rankin Scale < or =2 at 3 months)., Results: Eighty-nine patients were included in the analysis; 43 were MRI-screened, and 46 were CT-plus-MRI-screened. Although the MRI-screening group had a longer door-to-needle time (p<0.001), these patients showed better 3-month outcomes compared to CT-plus-MRI-screening group (p=0.01). Multivariate analysis showed that MRI screening (odds ratio 3.97, 95% confidence interval 1.30-12.17, p=0.02) was independently associated with a good outcome at 3 months. In CT-plus-MRI-screening group, although time-to-initial imaging and time-to-tPA were shorter, time-to-MRI and time-to-additional thrombolysis were delayed., Conclusion: These results suggest that early patient selection using MRI may be more effective than reduction of times-to-treatment in improvement of thrombolytic outcomes., (Copyright 2010 Elsevier B.V. All rights reserved.)

Background: Patients with intracranial atherosclerosis (ICAS) are at high risk of early recurrence or neurologic deterioration. Although minor stroke and transient ischemic attack (TIA) seem benign, their occurrence in patients with ICAS may lead to early neurological deterioration (END). We aimed to identify factors associated with END in ICAS patients presenting with acute minor stroke or TIA, with a focus on early MRI findings., Methods: This was a retrospective analysis of consecutive patients with acute minor stroke or TIA admitted within 12 h of symptom onset. Patients with moderate-severe stenosis of the middle cerebral artery or basilar artery (BA) were included. All patients underwent MRI, including diffusion-weighted imaging (DWI), and magnetic resonance angiography. DWI lesion patterns were classified as perforating artery infarcts, pial infarcts, territorial infarcts and border zone infarcts (BIs). END was diagnosed as an increase of > or =4 points on the National Institutes of Health Stroke Scale from baseline during the 1st week., Results: Of the 95 patients enrolled in the study, 14 (14.7%) developed END. Independent predictors of END were the presence of BIs on baseline DWI (odds ratio, OR, 7.21; 95% confidential interval, CI, 1.88-27.66; p = 0.004) and BA disease (OR, 4.33; 95% CI, 1.11-16.92; p = 0.035)., Conclusions: ICAS patients with BI and BA disease are at high risk of END after minor stroke or TIA. Early radiological findings may be helpful in predicting END and guiding early treatment strategies., (Copyright 2010 S. Karger AG, Basel.)

Background: An acute perfusion-diffusion mismatch is known to be the strongest predictor of infarct growth. However, the differential patterns of clinical and radiological evolution according to stroke mechanism are unknown., Methods: The study retrospectively reviewed consecutive patients who had 1) acute middle cerebral artery (MCA) territory infarction, 2) diffusion- and perfusion-weighted imaging (DWI and PWI) and MR angiography within 24 h of onset, and follow-up DWI 5 days later, 3) stenosis (> or =50%) or occlusion of MCA on baseline imaging, 4) a baseline PWI-DWI mismatch >20%, and 5) either atherosclerotic MCA disease (MCAD) or cardioembolism (CE). National Institutes of Health Stroke Scale (NIHSS) scores and infarct volume at baseline and 5 days were obtained., Results: Of 90 patients, 52 had MCAD and 38 had CE. At baseline, CE group had more severe stroke (median NIHSS, 9 vs. 5; p=0.001) and larger infarct volume (median 8.32 cc vs. 3.0 cc; p=0.034) than MCAD group. During the 1-week period, CE group had larger infarct volume growth (median 12.85 cc vs. 3.02 cc; p=0.004) than MCAD group, although clinical improvement based on NIHSS (baseline minus 5-day) tended to be higher for CE than MCAD group (median 3 vs. 1; p=0.08). The correlation between infarct volume and NIHSS score was stronger in CE (r=0.841) compared to MCAD (r=0.582) group at 5-day., Conclusions: Substantial differences in the clinico-radiological evolution of acute ischemic stroke exist according to stroke mechanism. These data emphasize the importance of the stroke mechanism in the design of MRI-based acute stroke trials.

Background and Purpose: A change in acute-to-chronic lesion volume has been proposed as a biomarker for stroke therapies. The objectives of this study were to determine the magnitude of lesion volume change after standard treatment with tissue plasminogen activator and to determine whether specific volume change thresholds can discriminate clinical responders from nonresponders., Methods: We measured lesion volume on diffusion weighted at baseline and on 90-day fluid attenuated inversion recovery MRI and scored 3-month modified Rankin Scale in consecutive patients treated with tissue plasminogen activator. We identified variables associated with excellent (modified Rankin Scale 0 to 1) and independent (modified Rankin Scale 0 to 2) outcomes., Results: We included 53 patients (mean age 69 years, median baseline National Institutes of Health Stroke Scale score 7). The mean acute-to-chronic lesion volume increase was 11.7 (+/-7.7) cm(3). In 23 patients, the chronic lesion was smaller than the baseline lesion. At 3 months, 32 patients had an excellent clinical outcome. Dichotomous volume change variables associated with outcome included decrease in volume >or=30% (P=0.004) and volume increase >or=5 cm(3) (P=0.002)., Conclusions: In patients given standard tissue plasminogen activator therapy, changes in lesion volume are associated with clinical outcome, and threshold lesion volumes can differentiate excellent and poor outcome, suggesting these as a potential marker of outcome.

Background: Intracerebral microbleeds (MBs) are frequently observed in intracerebral hemorrhage (ICH) patients. Although MBs have been shown to be pathogenetically related with ICH, it is not known whether MBs are predictors of recurrent ICHs., Methods: Among 220 acute symptomatic primary ICH patients, 112 patients who underwent gradient-echo T2*-weighted MR imaging (GRE) within 10 days after symptom onset were considered for this study. Among them, the final 63 patients who consented to follow-up clinical, laboratory and GRE studies were included. The presence and number of ICHs (mean diameter >5 mm) and MBs on baseline and follow-up GRE were evaluated. The relationship of recurrent ICHs with initial and follow-up clinical and laboratory data as well as the MBs was assessed., Results: Among 63 patients, 43 (68.3%) had MBs (median, 2; range, 1 to 17) on baseline GRE. Seven (11.1%) patients (6 with initial MBs; 1 without initial MBs) developed recurrent ICHs, and 19 (30.2%) had new MBs during a median 23.3 months (range, 8.3 to 33.0) of follow-up. The number of initial MBs on baseline GRE was significantly (p < 0.0001) associated with development of recurrent ICHs whereas other clinical and laboratory data were not., Conclusions: Recurrent ICHs and MBs are common after long-term follow-up of primary ICH. The number of MBs on baseline GRE may predict the recurrence of the ICH.

Background and Purpose: MRI screening for thrombolytic therapy may improve patient selection. Alternatively, it may excessively delay treatment and thereby lead to worse outcomes. We hypothesized that times to treatment and outcomes in a stroke center with immediate MRI access and interpretation would not differ from those of the typical clinical practice., Methods: We compared the results of 120 consecutive patients treated with intravenous tissue plasminogen activator (tPA) within 3 hours of onset at our center with those of the 2 largest multicenter registries of tPA use. In addition to standard criteria, MRI specific eligibility criteria were applied in 97 patients. MRI was not performed in 23 patients because of contraindications to MRI or late patient arrival (>2.5 hours). Outcomes were the modified Rankin Scale (mRS) obtained at 3 months., Results: Times to treatment (median door-to-needle time 81.5 minutes; median onset-to-needle time 135 minutes) and outcomes (mRS 0 to 1, 40.8%; mRS 0 to 2, 47.5%) were not inferior to those of the typical clinical practice. Door-to-needle time was shorter in computed tomography (CT) screening (67.5+/-22.5 minutes; n=23) than in MRI screening (86.8+/-21.5 minutes; n=97; P<0.001). However, outcomes were not different between MRI screening (mRS 0 to 1, 42.3%; mRS 0 to 2, 49.5%) and CT screening (mRS 0 to 1, 34.8%; mRS 0 to 2, 39.1%). Neither times to treatment nor MRI screening was predictive of outcomes., Conclusions: These data demonstrate that MRI screening before tPA therapy is feasible and not associated with unacceptable times to treatment or outcomes.

Background and Purpose: Analogous to the CT hyperattenuated vessel sign (HMCAS), MR imaging may show hypo- or hyperintense vessels in acute ischemic stroke (AIS) patients. We assessed the diagnostic and prognostic strength of early MR imaging vessel signs in AIS patients treated with intravenous thrombolysis (IVT) within 3 hours of the onset of symptoms., Methods: We studied AIS patients both treated with IVT and stroke MR imaged within 3 hours of the onset of symptoms and at 2 hours and 24 hours after treatment. We assessed the presence or absence of early vessel signs (hyperintense fluid-attenuated inversion recovery sign [FLAIR HVS]; gradient-echo susceptibility vessel sign [GRE SVS]) compared with a combined MR angiography/perfusion-weighted imaging reference and their strength for predicting clinical outcome (favorable vs. poor, independent vs. dependent, or dead, death), recanalization (by clot composition and flow), and hemorrhage in uni- and multivariate analysis., Results: Fifty-six patients (age range, 76 years +/- 13 years; median National Institutes of Health stroke scale score [NIHSSS], 11) met the inclusion criteria. Forty-four patients (78.6%) had a vessel occlusion at baseline; 22 of them (50%) recanalized. Nineteen patients (33.9%) suffered some form of intracranial hemorrhage (ICH), 24 patients (42.9%) had an independent outcome, 18 patients (32.1%) a favorable outcome, and 14 patients died. Compared with our combined reference for vessel status PWI/MRA, the sensitivities of CT HMCAS, FLAIR HVS, and GRE SVS were 40%, 66%, and 34%, respectively, and improved during the hours that followed. Localization was accurately reflected by FLAIR HVS but not by GRE SVS. Only NIHSSS and age were independent predictors for recanalization and all clinical outcomes in multiple logistic regression analysis., Conclusion: Although early vessel signs can be helpful in the diagnosis of intravascular disease, they do not independently predict recanalization, ICH, or any of the three clinical outcomes in a multivariate logistic regression model. Thrombus composition as reflected by signal intensity characteristics on GRE and FLAIR does not predict the therapeutic effect of IVT.

Background: Recent reports have indicated that cerebral microbleeds (CMBs) detected on gradient-echo (GRF) magnetic resonance imaging may be a risk factor for therapy related intracranial hemorrhages (ICHs)., Case Description: The authors describe 3 patients with multiple CMBs in whom ICHs occurred either after tissue plasminogen activator administration or after the initiation of antiplatelet therapy. Hemorrhages occurred in brain areas with normal appearances on GRE imaging and remote from the CMBs., Conclusion: Multiple CMBs may signal a diffuse hemorrhage-prone vasculopathy.

Background: The magnetic resonance (MR) imaging findings of hemichorea-hemiballismus (HCHB) associated with hyperglycemia are characterized by hyperintensities in the striatum on T1-weighted MR images and computed tomographic scans, with a mechanism of petechial hemorrhage considered to be responsible. Diffusion-weighted MR imaging (DWI) has been reported to detect early ischemic damage (cytotoxic edema) as bright areas of high signal intensity and vasogenic edema as areas of heterogeneous signal intensity. We report various DWI findings in 2 patients with hyperglycemic HCHB., Objectives: To describe the DWI and gradient echo findings and characterize the types of edema in HCHB associated with hyperglycemia., Setting: A tertiary referral center neurology department., Design and Methods: Two patients with HCHB associated with hyperglycemia underwent DWI, gradient echo imaging, and conventional MR imaging with gadolinium enhancement. The patients had an elevated serum glucose level on admission and a long history of uncontrolled diabetes, and the symptoms were controlled by dopamine receptor blocking agents. Initial DWIs were obtained 5 to 20 days after symptom onset. Apparent diffusion coefficient (ADC) values were measured in the abnormal lesions with visual inspection of DWI and T2-weighted echo planar images., Results: T1- and T2-weighted MR images and brain computed tomographic scans showed high signal intensities in the right head of the caudate nucleus and the putamen. Gradient echo images were normal. The DWIs showed bright high signal intensity in the corresponding lesions (patient 1), and the ADC values were decreased. The decrease in ADC and the high signal intensity on DWI persisted despite the disappearance of HCHB, even after 70 days., Conclusions: Gradient echo MR imaging findings were normal in HCHB with hyperglycemia, whereas DWI and the ADC map showed restricted diffusion, which suggests that hyperviscosity, not petechial hemorrhage, with cytotoxic edema can cause the observed MR abnormalities.

Background: Wernicke encephalopathy (WE) is a metabolic disorder of the central nervous system resulting from vitamin B(1) deficiency. The exact mechanisms underlying the pathogenesis of the lesions in WE are not completely understood. Vitamin B1 deficiency is associated with intracellular and extracellular edema by glutamate(N-methyl-D-aspartate) receptor-mediated excitotoxicity. Conventional magnetic resonance imaging (MRI) cannot differentiate the types of edema. Diffusion-weighted imaging (DWI) has been reported to detect early ischemic damage (cytotoxic edema) as bright areas of high signal intensity (SI) and vasogenic edema as areas of heterogeneous SI., Objectives: To describe the DWI findings and to characterize the types of edema in WE using DWI., Setting: Tertiary referral center., Design and Methods: Two patients with WE underwent DWI and conventional MRI with gadolinium enhancement. Wernicke encephalopathy was diagnosed with salient conventional MRI findings (high SIs in the paramedian thalamus, periaqueductal gray matter, and mamillary bodies) and typical clinical history and symptoms. Apparent diffusion coefficient (ADC) values were measured in abnormal lesions by visual inspection of DWIs and T2-weighted echo planar images., Results: T2-weighted and fluid-attenuated inversion recovery MRIs showed high SIs in the bilateral paramedian thalamus, mamillary bodies, and periaqueductal gray matter. The DWIs showed bright high SI in the corresponding lesions, and ADC values were decreased (patient 1: 512-545 x 10(-6)mm2/s; patient 2: 576-612 x 10(-6)mm2/s). The ADC decrease and the DWI high SI were normalized in 2 weeks with administration of thiamine hydrochloride., Conclusions: Abnormalities on DWI and ADC decrease became normalized with adequate therapy. The MRI abnormalities in WE might be owing to the "reversible cytotoxic edema" caused by vitamin B1 deficiency.

Background and aims:Assessment of ischemic lesions on computed tomography or MRI diffusion-weighted imaging (DWI) using the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) is widely used to guide acute stroke treatment. However, it has never been defined how many voxels need to be affected to label a DWI-ASPECTS region ischemic. We aimed to assess the effect of various lesion load thresholds on DWI-ASPECTS and compare this automated analysis with visual rating. Materials and methods:We analyzed overlap of individual DWI lesions of 315 patients from the previously published predictive value of fluid-attenuated inversion recovery study with a probabilistic ASPECTS template derived from 221 CT images. We applied multiple lesion load thresholds per DWI-ASPECTS region (>0, >1, >10, and >20% in each DWI-ASPECTS region) to compute DWI-ASPECTS for each patient and compared the results to visual reading by an experienced stroke neurologist. Results:By visual rating, median ASPECTS was 9, 84 patients had a DWI-ASPECTS score ≤7. Mean DWI lesion volume was 22.1 (±35) ml. In contrast, by use of >0, >1-, >10-, and >20%-thresholds, median DWI-ASPECTS was 1, 5, 8, and 10; 97.1% (306), 72.7% (229), 41% (129), and 25.7% (81) had DWI-ASPECTS ≤7, respectively. Overall agreement between automated assessment and visual rating was low for every threshold used (>0%: κw = 0.020 1%: κw = 0.151; 10%: κw = 0.386; 20% κw = 0.381). Agreement for dichotomized DWI-ASPECTS ranged from fair to substantial (≤7: >10% κ = 0.48; >20% κ = 0.45; ≤5: >10% κ = 0.528; and >20% κ = 0.695). Conclusion:Overall agreement between automated and the standard used visual scoring is low regardless of the lesion load threshold used. However, dichotomized scoring achieved more comparable results. Varying lesion load thresholds had a critical impact on patient selection by ASPECTS. Of note, the relatively low lesion volume and lack of patients with large artery occlusion in our cohort may limit generalizability of these findings.

Background and purposeAlberta Stroke Program Early Computed Tomographic Score (ASPECTS) has been used to estimate diffusion-weighted imaging (DWI) lesion volume in acute stroke. We aimed to assess correlations of DWI-ASPECTS with lesion volume in different middle cerebral artery (MCA) subregions and reproduce existing ASPECTS thresholds of a malignant profile defined by lesion volume ≥100 mL.MethodsWe analyzed data of patients with MCA stroke from a prospective observational study of DWI and fluid-attenuated inversion recovery in acute stroke. DWI-ASPECTS and lesion volume were calculated. The population was divided into subgroups based on lesion localization (superficial MCA territory, deep MCA territory, or both). Correlation of ASPECTS and infarct volume was calculated, and receiver-operating characteristics curve analysis was performed to identify the optimal ASPECTS threshold for ≥100-mL lesion volume.ResultsA total of 496 patients were included. There was a significant negative correlation between ASPECTS and DWI lesion volume (r=-0.78; P

Background: Chronic refractory cough significantly impairs the psychological and social aspects of quality of life. Loss of inhibitory control is suggested as a potential central neurobiological mechanism underlying chronic refractory cough.Research Question: Do structural and functional changes related to chronic cough occur in higher cortical brain regions?Study Design and Methods: The structural and resting-state functional alterations in the brains of 15 patients with chronic refractory cough and 15 age- and sex-matched healthy control participants were evaluated. Gray matter volumes of the whole brain were measured using voxel-based morphometry based on T1-weighted MRI. Intrinsic functional connectivity within large-scale brain networks was examined on resting-state functional MRI. Correlation analyses were performed to examine the relationships of these brain changes with duration, severity, and impact of cough.Results: Compared with healthy control participants, patients with chronic refractory cough demonstrated a lower gray matter volume in the left frontal cluster and enhanced functional connectivity within the left frontoparietal network, which were associated with greater cough scores. Furthermore, enhanced functional connectivity within the left frontoparietal network was associated with a greater psychological and social impact of coughing. Lower left frontal gray matter volume was associated with longer cough duration.Interpretation: Structural and functional alterations in the left frontal brain regions may be implicated in the psychological and social impact and disease duration of chronic refractory cough. Our findings provide new perspectives on developing interventional approaches targeting the cognitive modulation of chronic coughing. [ABSTRACT FROM AUTHOR]

Multimodal magnetic resonance imaging (MRI) has emerged as a promising tool for diagnosing ischemic stroke and for determining treatment strategies in the acute phase. The detection and quantification of the penumbra and the infarct core regions aid the assessment of the potential risks and benefits of thrombolysis by providing information on salvageable tissue or ischemic lesion age. In this study, we proposed a fully automated and real-time algorithm to compute parameter maps of perfusion-weighted images (PWIs) and to identify an infarct core from diffusion-weighted images (DWIs). DWI and PWI were obtained using a 1.5 Tesla MRI scanner for 15 patients with acute ischemic stroke. Parameter maps of PWI were computed using restricted gamma-variate curve fitting and Fourier-based deconvolution. The ischemic penumbra was identified using time-to-maximum (Tmax) > 6 s as the mutual optimal threshold, while the infarct core was segmented using an adaptive thresholding on DWI. When the penumbra on PWI was compared with that generated using commercial software Pearson's linear correlation coefficient between penumbra volumes was 0.601 (p = 0.030), and the Dice coefficient was 0.51 ± 0.15. The infarct core on DWI was compared with the manually segmented gold standard. Dice coefficient between the manually drawn and automated segmented infarct cores was 0.62 ± 0.18. The processing times for PWI and DWI were 222.9 ± 16.4 and 53.4 ± 4.8 s, respectively. In conclusion, we demonstrate a fully automated and real-time algorithm to segment the penumbra and the infarct core regions based on PWI and DWI. [ABSTRACT FROM AUTHOR]

Abstract: Although stroke is a leading cause of disability, the quantitative relationship between baseline clinical and imaging characteristics and long‐term disability outcomes has rarely been studied. Prospectively collected clinical data from 405 patients with acute ischemic stroke including brain magnetic resonance images (MRIs) and disability outcomes assessed using the modified Rankin Scale (mRS) 3 month after the onset of disease were analyzed using a proportional odds cumulative logit model implemented in NONMEM. The relationship between the difference in lesion volume (DLV) — lesion volume measured by brain MRI 5 days later — lesion volume at the onset of the disease, and the mRS measured at 3 months (mRS3) was modeled first, and the potential covariates were tested. The Emax model best described the relationship between DLV and the logit probability of each mRS3. DLV, baseline stroke severity, age, and diabetes mellitus were identified as significant predictors of the probabilities of mRS3. The quantitative model constructed in the current analysis will enable us to predict the long‐term disabilities of the patients with acute ischemic stroke using the patient‐specific MRI and other clinical information, which will be useful for individualizing therapies and for making the clinical development of a novel drug more efficient. [ABSTRACT FROM AUTHOR]

Background: The stroke mechanism for anterolateral pontine infarction (ALPI) is poorly understood. We aimed to investigate the perforator arteries relevant to ALPI using highresolution MRI (HR-MRI). Methods: Of 62 patients with ALPI who were admitted to the Asan Medical Center, 13 patients agreed to participate in this study. We used HR-MRI with a 3-Tesla scanner and assessed the perforating branches directly connected with the infarcted area. Results: Perforating arteries penetrating ALPI were identified in all 13 patients. Perforators arising from the basilar artery (BA) were involved in the stroke mechanism in 9 patients, the superior cerebellar artery (SCA) perforator in 1 patient, and the anterior inferior cerebellar artery perforator in 1 patient. In 2 patients, both BA and SCA perforators were involved. Conclusions: Using 3-Tesla HR-MRI may allow visualization of the perforating branches presumably related to ALPI. Identification of the relevant cerebral perforating arteries may help us to understand the stroke mechanism in patients with posterior circulation territory infarction. [ABSTRACT FROM AUTHOR]

Background: It is still controversial whether early fluid-attenuated inversion recovery (FLAIR) hyperintensity within acute ischemic lesions carries the risk of hemorrhagic transformation (HT) after reperfusion therapy. Furthermore, the association between the location of FLAIR hyperintensity and HT has not been investigated.Methods: We retrospectively reviewed patients who underwent reperfusion therapy within 6 hours of stroke onset and magnetic resonance imaging including a FLAIR sequence before completing reperfusion therapy. FLAIR hyperintensity within the diffusion-weighted imaging (DWI) lesion was rated qualitatively, and HT was assessed on follow-up gradient echo imaging. The location of the FLAIR change and HT was classified as subcortical, cortical, or cortico-subcortical.Results: Of 134 patients with acute ischemic stroke included in this study, early FLAIR changes within DWI lesions were identified in 56 (41.8%) patients, and HT was noted in 51 (38.1%) patients. FLAIR change was independently associated with HT (odds ratio: 4.37, 95% confidence interval: 1.72-11.12). Geographically, 48.2% of the patients with a FLAIR change developed a matched HT (restricted to the region with the FLAIR change), and the risk of HT was further increased in patients with a FLAIR change in the cortico-subcortical region (68.8%).Conclusions: In patients in the acute stage of stroke, an early FLAIR change is associated with the risk of HT following reperfusion therapy with a highly matched geographic relationship and common risk factors. Thus, identification of FLAIR change may be a useful surrogate marker to assess the likelihood of subsequent HT in patients treated with reperfusion therapy. [ABSTRACT FROM AUTHOR]

Objectives: The prognosis of a cerebral artery dissection is known to be benign, but the structural changes of vessel wall at follow-up are not well known. The natural course of an intracranial and extracranial artery dissection may differ due to structural differences. We aimed to figure out how stenosis and other wall features change, according to the dissection location.Materials and Methods: We retrospectively enrolled patients who suffered an ischemic stroke or transient ischemic attack due to a dissection and who had undergone both initial and follow-up high-resolution magnetic resonance imaging (HRMRI). Patients were dichotomized to intracranial or extracranial dissection group. The clinical and HRMRI characteristics of two groups were compared. Factors associated with stenosis changes were also investigated.Results: A total of 57 patients (intracranial, n = 43; and extracranial, n = 14) were enrolled. The mean age (45.6 vs. 32.2, p < 0.001) was higher and hypertension (37.2% vs. 7.1%, p = 0.04) was more frequent in the intracranial dissection group. In HRMRI analysis, stenosis improvement (27.9% vs. 85.7%, p < 0.001) were more frequent whereas residual wall enhancement (86.0% vs. 46.2%, p = 0.006) and intramural hematoma (62.8% vs. 21.4%, p = 0.007) were less frequent in the extracranial dissection group. Multivariate analysis indicated that extracranial location was the only independent factor (odds ratio 8.98, 95 % confidence interval 1.45-55.65; p = 0.02) associated with stenosis improvement.Conclusions: Younger age, stenosis improvement, disappearance of wall enhancement and intramural hematoma were more frequent in an extracranial dissection compared with an intracranial dissection. An extracranial location is independently associated with stenosis improvement in dissection patients. [ABSTRACT FROM AUTHOR]

Background: The effect of biochemical aspirin resistance (BAR) on ischemic stroke has not been well established. Early recurrent ischemic lesions (ERILs) on diffusion-weighted imaging (DWI) are proposed as potential surrogate markers of clinically recurrent stroke. Methods: We included 117 consecutive patients who (1) were admitted within 24 h of symptom onset; (2) had an ischemic stroke confirmed by DWI; (3) underwent follow-up DWI within seven days after onset, and (4) received aspirin treatment. BAR was measured using the VerifyNow® Aspirin Assay. We analyzed the associations between BAR and any ERILs (overall ERILs), and between BAR and ERILs occurring outside the vascular territories of index stroke (distant ERILs). Results: BAR was observed in 16 (13.7%) patients. Overall ERILs were detected in 34 (29.1%), and distant ERILs in 10 (8.5%) patients. Patients with BAR were more likely to develop ERILs, but the association was not significant (OR 2.13; 95% CI 0.72–6.29; p = 0.234). However, BAR was independently related to distant ERILs by logistic regression analysis (OR 6.01; 95% CI 1.29–28.09; p = 0.023). Conclusions: BAR was associated with distant ERILs but not with overall ERILs during the first week after ischemic stroke. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background and Purpose: The ‘lacunar hypothesis’ has been challenged, since small (diameter <15 mm) subcortical infarcts can be produced by middle cerebral artery disease (MCAD) or cardioembolism (CE), while a larger infarct can occur without evidence of MCAD or CE. We sought to assess whether the lacunar hypothesis based on size is still valid. Methods: We studied 118 patients who were admitted within 72 h after stroke onset and had acute deep subcortical MCA territory infarcts detected by diffusion-weighted MRI, and who had undergone angiography (mostly MR angiography). Stroke mechanisms were arbitrarily categorized regardless of lesion size: (1) MCAD when there was a corresponding MCA lesion; (2) internal carotid artery disease (ICAD) when there was a significant (>50%) ipsilateral ICAD; (3) CE when there was emboligenic heart disease without MCAD or ICAD, and (4) small vessel disease (SVD) when there was neither CE nor MCAD. SVD was further divided into definite SVD (dSVD, longest diameter <15 mm) or probable SVD (pSVD, longest diameter ≥15 mm). Results: Seventy-three patients (62%) had SVD, of which 38 (32%) had pSVD and 35 (30%) dSVD. Thirty-three patients (28%) had MCAD, five (4%) CE, and seven (6%) ICAD. The infarct diameter in MCAD was not larger than in SVD (p = 0.35), and there was no difference in clinical features or risk factors between MCAD and SVD, or between pSVD and dSVD. CE was distinguished from SVD by its larger size and cortical symptoms. Conclusions: There are no clinical and lesion-size differences between MCAD and SVD, suggesting that there seems to be no rationale for the 15 mm size criterion for lacunar or small-vessel infarction. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: In human and experimental models, diffusion-weighted magnetic resonance imaging (DWI) findings in status epilepticus (SE) have been reported to show that apparent diffusion coefficients are reduced during the initial phase and normalized or increased in the later phase of prolonged SE. This effect is caused by cytotoxic edema induced by excitotoxicity. In humans, only focal DWI abnormalities have been reported in partial SE. Objectives: To report and discuss the DWI findings suggesting diffuse neuronal injury in a patient with nonconvulsive SE. Design and Methods: A 56-year-old man was admitted because of changing levels of consciousness over 3 days. On admission he was comatose. He had nystagmoid eye movement, forced eye blinking, and oroalimentary automatism. The results of a search for possible infectious and metabolic etiologies were negative, and electroencephalographic findings showed continuous, semirhythmic, bifrontal sharp waves of 2 Hz. Phenytoin and midazolam hydrochloride were infused to alleviate the seizure activities. He underwent DWI initially (3 days after the onset of seizure) and at the 5-month follow-up. Setting: The neurology department of a tertiary referral center. Results: During SE, DWI findings showed marked, diffuse gyriform cortical hyperintensity throughout the brain. The apparent diffusion coefficient decreased in the corresponding areas, especially in the occipital lobes. Findings from T2-weighted magnetic resonance imaging showed the intense cortical hyperintensity with gyral swelling and no involvement of brainstem, basal ganglia, thalamus, and white matter. The follow-up DWI findings showed marked atrophy and hypointensity in the corresponding regions. The apparent diffusion coefficient increased in the corresponding regions. Conclusions: Diffusion-weighted imaging in our patient indicated that the magnetic resonance imaging abnormalities of the affected cortex were due to cytotoxic edema caused by neuronal exc... [ABSTRACT FROM AUTHOR]

Discusses the case of diffusion-weighted imaging findings in brain stem hypertensive encephalopathy (HE). Neurologic examination; Results of the magnetic resonance imaging; Mechanisms which have been discussed with respect to the high signals in HE.

Background and purpose Although cervicocranial artery dissections (CADs) are common causes of ischemic stroke in young individuals, anatomical locations and mechanisms of ischemic strokes are still unclear. We evaluate the prevalence, location, and pathogenic mechanisms of ischemic stroke caused by CADs. Methods We reviewed CAD patients who presented with acute (< 7 days) ischemic events and who had undergone diffusion weighted magnetic resonance imaging (MRI) and appropriate vascular imagings (MR angiography, computed tomography angiography, digital subtraction angiography, and high-resolution MRI). Stroke mechanisms were categorized as artery-to-artery (AA) embolism, local branch occlusion, in situ thrombotic occlusion and hemodynamic impairment. Results One hundred and thirty-five patients with cerebral infarcts (n = 125) or transient ischemic attacks (n = 10) were included. The locations of 159 dissected vessels were: 77 vertebral, 29 internal carotid, 24 middle cerebral, 12 basilar, eight posterior inferior cerebellar, five anterior cerebral, and four posterior cerebral arteries. Among stroke mechanisms, A–A embolism (n = 70, 55.5%) was the most common followed by local branch occlusions (n = 40, 31.7%) and in situ thrombotic occlusions (n = 8, 6.3%). Intracranial CADs were more common (89 vs. 44), less often associated with trauma (21.3% vs. 40.9%, p = 0.018) and A–A embolism (32.9% vs. 97.6%, p < 0.001), and more often treated with intravenous thrombolysis (15.7% vs. 2.3%. p = 0.021) than extracranial CADs. Conclusions In our cohort, intracranial CADs are more common than extracranial CADs, and the vertebral artery is the most frequently involved site. Although A–A embolism is the main stroke mechanism, local branch occlusion is another important stroke mechanism. [ABSTRACT FROM AUTHOR]

Summary: Background: Many patients with stroke are precluded from thrombolysis treatment because the time from onset of their symptoms is unknown. We aimed to test whether a mismatch in visibility of an acute ischaemic lesion between diffusion-weighted MRI (DWI) and fluid-attenuated inversion recovery (FLAIR) MRI (DWI-FLAIR mismatch) can be used to detect patients within the recommended time window for thrombolysis. Methods: In this multicentre observational study, we analysed clinical and MRI data from patients presenting between Jan 1, 2001, and May 31, 2009, with acute stroke for whom DWI and FLAIR were done within 12 h of observed symptom onset. Two neurologists masked to clinical data judged the visibility of acute ischaemic lesions on DWI and FLAIR imaging, and DWI-FLAIR mismatch was diagnosed by consensus. We calculated predictive values of DWI-FLAIR mismatch for the identification of patients with symptom onset within 4·5 h and within 6 h and did multivariate regression analysis to identify potential confounding covariates. This study is registered with ClinicalTrials.gov, number NCT01021319. Findings: The final analysis included 543 patients. Mean age was 66·0 years (95% CI 64·7–67·3) and median National Institutes of Health Stroke Scale score was 8 (IQR 4–15). Acute ischaemic lesions were identified on DWI in 516 patients (95%) and on FLAIR in 271 patients (50%). Interobserver agreement for acute ischaemic lesion visibility on FLAIR imaging was moderate (κ=0·569, 95% CI 0·504–0·634). DWI-FLAIR mismatch identified patients within 4·5 h of symptom onset with 62% (95% CI 57–67) sensitivity, 78% (72–84) specificity, 83% (79–88) positive predictive value, and 54% (48–60) negative predictive value. Multivariate regression analysis identified a longer time to MRI (p<0·0001), a lower age (p=0·0009), and a larger DWI lesion volume (p=0·0226) as independent predictors of lesion visibility on FLAIR imaging. Interpretation: Patients with an acute ischaemic lesion detected with DWI but not with FLAIR imaging are likely to be within a time window for which thrombolysis is safe and effective. These findings lend support to the use of DWI-FLAIR mismatch for selection of patients in a future randomised trial of thrombolysis in patients with unknown time of symptom onset. Funding: Else Kröner-Fresenius-Stiftung, National Institutes of Health. [Copyright &y& Elsevier]