Time Window for Induced Hypertension in Acute Small Vessel Occlusive Stroke With Early Neurological Deterioration.

BACKGROUND: Therapeutic-induced hypertension treatment (iHTN) is helpful for alleviating early neurological deterioration (END) in acute small vessel occlusive stroke. We examined the time parameters related to iHTN effectiveness in these patients. METHODS: We retrospectively reviewed patients with acute small vessel occlusive stroke who underwent iHTN for END, defined as an increase of ≥2 points in total National Institutes of Health Stroke Scale (NIHSS) score or ≥1 point in motor items of NIHSS. The primary outcome was an early neurological improvement (ENI; a decrease of ≥2 points in total NIHSS score or ≥1 point in motor items of NIHSS), and the secondary outcome was any neurological improvement (a decrease of ≥1 point in the total NIHSS score). We conducted a multivariable logistic regression analysis, adjusting for demographics, risk factors, baseline clinical status, and intervention-related variables. We also generated a restricted cubic spline curve for the END-to-iHTN time cutoff. RESULTS: Among the 1062 patients with small vessel occlusive stroke screened between 2017 and 2021, 136 patients who received iHTN within 24 hours from END were included. The mean age was 65.1 (±12.0) years, and 61.0% were male. Sixty-five (47.8%) patients showed ENI and 77 (56.6%) patients showed any neurological improvement. END-to-iHTN time was significantly shorter in patients with ENI (150 [49-322] versus 290 [97-545] minutes; P=0.018) or any neurological improvement (150 [50-315] versus 300 [130-573] minutes; P=0.002). A 10-minute increase in the time between END and iHTN decreased the odds of achieving ENI (odds ratio, 0.984 [95% CI, 0.970-0.997]; P=0.019) or any neurological improvement (odds ratio, 0.978 [95% CI, 0.964-0.992]; P=0.002). The restricted cubic spline curve showed that the odds ratio of ENI reached its minimum at ≈3 hours. CONCLUSIONS: Among patients with small vessel occlusive stroke with END, a shorter interval between END and the initiation of iHTN was associated with increased odds of achieving neurological improvement. The efficacy of iHTN may be limited to induction within the first 3 hours of END.

Association between Rapid Ventricular Response and Stroke Outcomes in Atrial Fibrillation-Related Cardiac Embolic Stroke.

INTRODUCTION: Patients with atrial fibrillation-related stroke (AF-stroke) are prone to developing rapid ventricular response (RVR). We investigated whether RVR is associated with initial stroke severity, early neurological deterioration (END) and poor outcome at 3 months. METHODS: We reviewed patients who had AF-stroke between January 2017 and March 2022. RVR was defined as having heart rate >100 beats per minute on initial electrocardiogram. Neurological deficit was evaluated with National Institutes of Health Stroke Scale (NIHSS) score at admission. END was defined as increase of ≥2 in total NIHSS score or ≥1 in motor NIHSS score within first 72 h. Functional outcome was score on modified Rankin Scale at 3 months. Mediation analysis was performed to examine potential causal chain in which initial stroke severity may mediate relationship between RVR and functional outcome. RESULTS: We studied 568 AF-stroke patients, among whom 86 (15.1%) had RVR. Patients with RVR had higher initial NIHSS score (p < 0.001) and poor outcome at 3 months (p = 0.004) than those without RVR. The presence of RVR [adjusted odds ratio (aOR) = 2.13; p = 0.013] was associated with initial stroke severity, but not with END and functional outcome. Otherwise, initial stroke severity [aOR = 1.27; p = <0.001] was significantly associated with functional outcome. Initial stroke severity as a mediator explained 58% of relationship between RVR and poor outcome at 3 months. CONCLUSION: In patients with AF-stroke, RVR was independently associated with initial stroke severity but not with END and functional outcome. Initial stroke severity mediated considerable proportion of association between RVR and functional outcome.

Association between renal insufficiency and lesion characteristics of posterior reversible encephalopathy syndrome.

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/1.73m2 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 (ß = -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.

Early Response to Endovascular Thrombectomy after Stroke: Early, Late, and Very Late Time Windows.

BACKGROUND AND PURPOSE: Endovascular thrombectomy (EVT) has benefits in selected patients 6-24 h after stroke onset. However, the response to EVT >24 h after stroke onset is still unclear. We compared the early response to EVT in patients with different time windows. METHODS: Patients who underwent EVT in an emergency setting were enrolled and categorized according to when EVT was performed: within 6 (early), 6-24 (late), and >24 h (very late) after stroke onset. Early neurological improvement (ENI) and deterioration (END) were defined as improvement and worsening, respectively, of National Institutes of Health Stroke Scale (NIHSS) score by ≥4 points after EVT. The three groups' clinical characteristics and response to EVT were compared. We also investigated factors associated with ENI and END. RESULTS: During study period, 274 patients underwent EVT (109 early, 104 late, and 61 very late). Patients who underwent EVT very late were younger (p = 0.007), had smaller ischemic cores, and had lower initial NIHSS scores (8 ± 5) than those who underwent EVT early (14 ± 6) and late (13 ± 7; p < 0.001). Stroke mechanisms also differed according to the time window (p < 0.001): cardioembolism was more common after early EVT, whereas large-artery atherosclerosis was more prevalent among patients who underwent EVT very late. ENI was significantly more common after early (60.6%) and late EVT (51.0%) than after very late EVT (29.5%; p = 0.001); however, rates of END did not differ (11.0%, 13.5%, and 4.9%, respectively). ENI was independently associated with male, higher NIHSS score, and early and late EVT. END was associated with failure of recanalization. CONCLUSIONS: ENI was more observed and associated with early and late EVT. Highly selected patients receiving very late EVT may not benefit from ENI but may still have a chance to prevent END. The occurrence of END was associated not with time window but with failure of recanalization.

In-stent restenosis and stented-territory infarction after carotid and vertebrobasilar artery stenting.

BACKGROUND: Prognosis after vertebrobasilar stenting (VBS) may differ from that after carotid artery stenting (CAS). Here, we directly compared the incidence and predictors of in-stent restenosis and stented-territory infarction after VBS and compared them with those of CAS. METHODS: We enrolled patients who underwent VBS or CAS. Clinical variables and procedure-related factors were obtained. During the 3 years of follow-up, in-stent restenosis and infarction were investigated in each group. In-stent restenosis was defined as reduction in the lumen diameter > 50% compared with that after stenting. Factors associated with the occurrence of in-stent restenosis and stented-territory infarction in VBS and CAS were compared. RESULTS: Among 417 stent insertions (93 VBS and 324 CAS), there was no statistical difference in in-stent restenosis between VBS and CAS (12.9% vs. 6.8%, P = 0.092). However, stented-territory infarction was more frequently observed in VBS than in CAS (22.6% vs. 10.8%; P = 0.006), especially a month after stent insertion. HbA1c level, clopidogrel resistance, and multiple stents in VBS and young age in CAS increased the risk of in-stent restenosis. Diabetes (3.82 [1.24-11.7]) and multiple stents (22.4 [2.4-206.4]) were associated with stented-territory infarction in VBS. However, in-stent restenosis (odds ratio: 15.1, 95% confidence interval: 3.17-72.2) was associated with stented-territory infarction in CAS. CONCLUSIONS: Stented-territory infarction occurred more frequently in VBS, especially after the periprocedural period. In-stent restenosis was associated with stented-territory infarction after CAS, but not in VBS. The mechanism of stented-territory infarction after VBS may be different from that after CAS.

Enlarged left atrium may be associated with laterality of anterior circulation cardioembolic stroke.

BACKGROUND: Propensity for lesion lateralization in atrial fibrillation-related cardiac embolic stroke (AF-stroke) remains controversial. In this study, we compared the hemispheric differences among patients with AF-stroke and identified factors associated with lesion laterality. METHODS: We retrospectively reviewed patients with acute AF-stroke admitted from January, 2017 to March, 2022. Patients were grouped based on whether lesions were right or left hemispheric in the anterior circulation territory, based on diffusion-weighted imaging. Factors associated with right-side propensity were analyzed. RESULTS: Among 385 patients, the mean age was 74±11 years and 52.5 % were male. Right and left hemispheric lesions were observed in 189 (49.1 %) and 196 (50.9%) patients, respectively. In the multivariate analysis, enlarged left atrium (LA) (adjusted odds ratio [aOR]=1.03, 95% confidential interval [CI], 1.007-1.061; p=0.013) and single confluent lesion pattern (aOR= 1.55, 95% CI, 1.012-2.381; p=0.044) were associated with right hemispheric lesions. CONCLUSIONS: Enlarged LA and single confluent lesion pattern were strongly related to right-sided propensity in patients with AF-stroke.

Clinical-Diffusion Mismatch Is Associated with Early Neurological Improvement after Late-Window Endovascular Treatment.

BACKGROUND: Clinical-diffusion mismatch (CDM) and perfusion-diffusion mismatch (PDM) are used to select patients for endovascular thrombectomy (EVT) in the late-window period. As CDM well reflects true penumbra, we hypothesized that patients with CDM and PDM would respond better to EVT than those with PDM only at the late-window period. METHODS: Acute ischemic stroke patients who received EVT 6-24 h after stroke onset were included. PDM (perfusion-/diffusion-weighted image (DWI) lesion volume >1.8) was used to select candidates for EVT in this time-period in our center. CDM was defined according to the DAWN trial criteria. Response to EVT was compared between patients with and without CDM. Early neurological improvement (ENI) was defined as improvement >4 points on National Institutes of Health Stroke Scale (NIHSS) score 1 day after EVT. Multivariable analysis was performed to investigate independent factors associated with ENI. The correlation between DWI lesion volume and NIHSS score was investigated in those with and without CDM. RESULTS: Among 94 patients enrolled, all patients had PDM and 44 (46.3%) had CDM. Forty-eight patients (51.1%) showed ENI. The prevalence of hypertension, initial NIHSS score, improvement in NIHSS score after EVT, and prevalence of ENI were greater in patients with CDM than those without. ENI was independently associated with onset-to-door time (odds ratio [95% confidence interval]: 0.998 [0.997-1.000]; p = 0.042), complete recanalization (23.912 [2.238-255.489]; p = 0.009), initial NIHSS score (1.180 [1.012-1.377]; p = 0.034), and the presence of CDM (5.160 [1.448-18.386]; p = 0.011). The correlation between DWI lesion volume and initial NIHSS score was strong in patients without CDM (r = 0.731) but only moderate in patients with CDM (r = 0.355). CONCLUSION: Patients with both CDM and PDM had a better response to late-window EVT than those with PDM only.

High serum total cholesterol associated with good outcome in endovascular thrombectomy for acute large artery occlusion.

BACKGROUND: The effect of cholesterol on the functional outcome after endovascular thrombectomy (EVT) is still controversial. This study aimed to investigate whether the lipid profile is associated with the EVT prognosis. METHODS: We retrospectively analyzed patients with emergent large vessel occlusion who underwent EVT. The blood lipid levels were measured in the fasting state, 1 day after admission. We divided patients into terciles of serum total cholesterol (TC) levels and compared the clinical characteristics among the groups. The factors associated with a good outcome at 3 months (modified Rankin scale 0-2) were investigated, considering the stroke mechanism and recanalization status. RESULTS: Among 274 patients, good outcomes were observed in 108 (39.4%) patients. Low initial severity (odds ratio (OR), 0.91, 95% confidence interval (CI), 0.858-0.954; p < 0.001) and high TC level (1.35, 1.034-1.758; p = 0.041) were associated with good outcomes. In patients with cardioembolism, young age (0.95, 0.915-0.991; p = 0.021), low initial severity (0.92, 0.857-0.988; p = 0.024), and high TC level (1.60, 1.019-2.499; p = 0.036) were associated with good outcomes. The lipid profile was not associated with a functional outcome in those with large artery atherosclerosis. In patients with complete recanalization, young age (0.97, 0.941-0.994; p = 0.016), low initial severity (0.91, 0.864-0.961; p = 0.001), absence of diabetes (0.45, 0.218-0.947; p = 0.035) or any hemorrhage (0.33, 0.142-0.760; p = 0.009), and high TC level (1.40, 1.031-1.879; p = 0.031) were associated with good outcomes. CONCLUSIONS: A high TC level was associated with favorable outcomes after EVT, especially in patients with cardioembolism and complete recanalization.

Structural Changes of Intra and Extracranial Artery Dissection: a Study of High-Resolution Magnetic Resonance Imaging.

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.

Early Impairment in the Ventral Visual Pathway Can Predict Conversion to Dementia in Patients With Amyloid-negative Amnestic Mild Cognitive Impairment.

BACKGROUND: Around 15% to 20% of patients with clinically probable Alzheimer disease have been found to have no significant Alzheimer pathology on amyloid positron emission tomography. A previous study showed that conversion to dementia from amyloid-negative mild cognitive impairment (MCI) was observed in up to 11% of patients, drawing attention to this condition. OBJECT: We gathered the detailed neuropsychological and neuroimaging data of this population to elucidate factors for conversion to dementia from amyloid-negative amnestic MCI. METHODS: This study was a single-institutional, retrospective cohort study of amyloid-negative MCI patients over age 50 with at least 36 months of follow-up. All subjects underwent detailed neuropsychological testing, 3 tesla brain magnetic resonance imaging), and fluorine-18(18F)-florbetaben amyloid positron emission tomography scans. RESULTS: During the follow-up period, 39 of 107 (36.4%) patients converted to dementia from amnestic MCI. The converter group had more severe impairment in all visual memory tasks. The volumetric analysis revealed that the converter group had significantly reduced total hippocampal volume on the right side, gray matter volume in the right lateral temporal, lingual gyri, and occipital pole. CONCLUSION: Our study showed that reduced gray matter volume related to visual memory processing may predict clinical progression in this amyloid-negative MCI population.

Neuro-Ophthalmologic Features and Outcomes of Thalamic Infarction: A Single-Institutional 10-Year Experience.

BACKGROUND: Neuro-ophthalmologic deficit after thalamic infarction has been of great concern to ophthalmologists because of its debilitating impacts on patients' daily living. We aimed to describe the visual and oculomotor features of thalamic infarction and to delineate clinical outcomes and prognostic factors of the oculomotor deficits from an ophthalmologic point of view. METHODS: Clinical and neuroimaging data of all participants were retrospectively reviewed. Among the 12,755 patients with first-ever ischemic stroke, who were registered in our Stroke Data Bank between January 2009 and December 2018, 342 were found to have acute thalamic infarcts on MRI, from whom we identified the patients exhibiting neuro-ophthalmologic manifestations including visual, oculomotor, pupillary, and eyelid anomalies. RESULTS: Forty (11.7%) of the 342 patients with thalamic infarction demonstrated neuro-ophthalmologic manifestations, consisting of vertical gaze palsy (n = 19), skew deviation with an invariable hypotropia of the contralesional eye (n = 18), third nerve palsy (n = 11), pseudoabducens palsy (n = 9), visual field defects (n = 7), and other anomalies such as isolated ptosis and miosis (n = 7). Paramedian infarct was the most predominant lesion of neuro-ophthalmologic significance, accounting for 84.8% (n = 28) of all patients sharing the oculomotor features. Although most of the patients with oculomotor abnormalities rapidly improved without sequelae, 6 (18.2%) patients showed permanent oculomotor deficits. Common clinical features of patients with permanent oculomotor deficits included the following: no improvement within 3 months, combined upgaze and downgaze palsy, and the involvement of the paramedian tegmentum of the rostral midbrain. CONCLUSIONS: Thalamic infarction, especially in paramedian territory, can cause a wide variety of neuro-ophthalmologic manifestations, including vertical gaze palsy, skew deviation, and third nerve palsy. Although most oculomotor abnormalities resolve spontaneously within a few months, some may persist for years when the deficits remain unimproved for more than 3 months after stroke.

Machine Learning Approach to Identify Stroke Within 4.5 Hours.

Background and Purpose- We aimed to investigate the ability of machine learning (ML) techniques analyzing diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging to identify patients within the recommended time window for thrombolysis. Methods- We analyzed DWI and FLAIR images of consecutive patients with acute ischemic stroke within 24 hours of clear symptom onset by applying automatic image processing approaches. These processes included infarct segmentation, DWI, and FLAIR imaging registration and image feature extraction. A total of 89 vector features from each image sequence were captured and used in the ML. Three ML models were developed to estimate stroke onset time for binary classification (≤4.5 hours): logistic regression, support vector machine, and random forest. To evaluate the performance of ML models, the sensitivity and specificity for identifying patients within 4.5 hours were compared with the sensitivity and specificity of human readings of DWI-FLAIR mismatch. Results- Data from a total of 355 patients were analyzed. DWI-FLAIR mismatch from human readings identified patients within 4.5 hours of symptom onset with 48.5% sensitivity and 91.3% specificity. ML algorithms had significantly greater sensitivities than human readers (75.8% for logistic regression, P=0.020; 72.7% for support vector machine, P=0.033; 75.8% for random forest, P=0.013) in detecting patients within 4.5 hours, but their specificities were comparable (82.6% for logistic regression, P=0.157; 82.6% for support vector machine, P=0.157; 82.6% for random forest, P=0.157). Conclusions- ML algorithms using multiple magnetic resonance imaging features were feasible even more sensitive than human readings in identifying patients with stroke within the time window for acute thrombolysis.

Cilostazol Versus Aspirin in Ischemic Stroke Patients With High-Risk Cerebral Hemorrhage: Subgroup Analysis of the PICASSO Trial.

Background and Purpose- Although cilostazol has shown less hemorrhagic events than aspirin, only marginal difference was observed in hemorrhagic stroke events among patients at high risk for cerebral hemorrhage. To identify patients who would most benefit from cilostazol, this study analyzed interactions between treatment and subgroups of the PICASSO trial (Prevention of Cardiovascular Events in Asian Ischemic Stroke Patients With High Risk of Cerebral Hemorrhage). Methods- Ischemic stroke patients with a previous intracerebral hemorrhage or multiple microbleeds were randomized to treatment with cilostazol or aspirin and followed up for a mean 1.8 years. Efficacy, defined as the composite of any stroke, myocardial infarction, and vascular death, and safety, defined as the incidence of hemorrhagic stroke, were analyzed in the 2 groups. Interactions between treatment and age, sex, presence of hypertension and diabetes mellitus, index of high-risk cerebral hemorrhage, and white matter lesion burden were analyzed for primary and key secondary outcomes. Changes in vital signs and laboratory results were compared in the 2 groups. Results- Among all 1534 patients enrolled, a significant interaction between treatment group and index of high risk for cerebral hemorrhage on hemorrhagic stroke (P for interaction, 0.03) was observed. Hemorrhagic stroke was less frequent in the cilostazol than in the aspirin group in patients with multiple microbleeds (1 versus 13 events; hazard ratio, 0.08 [95% CI, 0.01-0.61]; P=0.01). A marginal interaction between treatment group and white matter change on any stroke (P for interaction, 0.08) was observed. Cilostazol reduced any stroke significantly in patients with mild (5 versus 16 events; hazard ratio, 0.36 [95% CI, 0.13-0.97]; P=0.04)-to-moderate (16 versus 32 events; hazard ratio, 0.50 [95% CI, 0.29-0.92]; P=0.03) white matter changes. Heart rate and HDL (high-density lipoprotein) cholesterol level were significantly higher in the cilostazol group than in the aspirin group at follow-up. Conclusions- Cilostazol may be more beneficial for ischemic stroke patients with multiple cerebral microbleeds and before white matter changes are extensive. Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT01013532.

Repeatability of amide proton transfer-weighted signals in the brain according to clinical condition and anatomical location.

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.

Are Genetic Variants Associated with the Location of Cerebral Arterial Lesions in Stroke Patients?

BACKGROUND: Genetic variants may play a role in determining the location of cerebral atherosclerosis. We aimed to investigate the association between RNF213, MMP2, and genetic polymorphisms linked to vascular tortuosity with the location of cerebral arterial atherosclerosis. METHODS: A prospective case-control study was conducted on patients with ischemic stroke and age- and sex-matched stroke-free controls. The stroke patients were categorized into those with intracranial artery atherosclerosis (ICAS), extracranial artery atherosclerosis (ECAS), and small vessel occlusion (SVO). Six single nucleotide polymorphisms (SNPs) including rs2118181 (FBN1), rs2179357 (SLC2A10), rs1036095 (TGFBR2), rs243865 (MMP2), rs1800470 (TGFB1), and rs112735431 (RNF213) were analyzed with the TaqMan Genotyping Assay, and the distribution of genotypes across groups was compared. RESULTS: None of the 6 SNPs were associated with stroke on comparing the 449 stroke patients (71 with ECAS, 169 with ICAS, and 209 with SVO) to the 447 controls. In the subgroup analysis, the adjusted odds ratios (aORs) for age and sex indicated a significant association between rs112735431 and ICAS in the allele comparison analysis and in the additive and dominant model analyses. rs112735431 was associated with anterior circulation involvement and increased burden of cerebral atherosclerosis. rs2179357 was significantly associated with ICAS in the recessive model analysis, and rs1800470 was significantly associated with ECAS in the recessive model analysis when compared to controls. CONCLUSION: rs112735431 was associated with ICAS and increased atherosclerosis burden in Korean stroke patients. Further studies are needed to elucidate the role of rs112735431 and to confirm the association of rs2179357 and rs1800470 with cerebral atherosclerosis.

Fully Automated and Real-Time Volumetric Measurement of Infarct Core and Penumbra in Diffusion- and Perfusion-Weighted MRI of Patients with Hyper-Acute Stroke.

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.

Reliability of fast magnetic resonance imaging for acute ischemic stroke patients using a 1.5-T scanner.

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.

Lateral Medullary Infarction with or without Extra-Lateral Medullary Lesions: What Is the Difference?

BACKGROUND: Lateral medullary infarction (LMI) is not an uncommon disease. Although lesions are usually restricted to the lateral medullary area, some patients have additional infarcts in other parts of the brain. The clinical features and prognosis of isolated LMI (pure LMI, LMIpr) have been investigated. However, it remains unclear whether clinical characteristics, prognosis and factors associated with prognosis differ between patients with LMIpr and those with additional lesions (LMI plus, LMIpl). METHODS: Patients with LMI identified by MRI were enrolled. The demographic and clinical characteristics, in-hospital outcome (intensive care unit [ICU] admission, pneumonia and modified Rankin scale [mRS] at discharge), and long-term residual symptoms (vertigo/dizziness, sensory disturbances, dysphagia) and outcomes (occurrence of stroke, acute coronary syndrome [ACS], death, and mRS at follow-up) were compared between LMIpr and LMIpl patients. Factors associated with poor functional outcome (mRS 2-6) at the follow-up were analyzed. RESULTS: Among 248 LMI patients, 161 (64.9%) had LMIpr and 87 (35.1%) had LMIpl. During admission, patients with LMIpl more frequently experienced ICU care, pneumonia and had a higher discharge mRS (3 vs. 2; p < 0.001) than LMIpr patients. The occurrence of stroke, ACS, frequency of death and functional outcome was not different during follow-up. However, residual neurologic symptoms such as dizziness (p = 0.002), dysphagia (p = 0.04) and sensory symptoms (p < 0.001) were more frequent in LMIpr than in LMIpl patients. In LMIpr patients, the rostral location of LMI was associated with poor functional outcome (p = 0.041), whereas in LMIpl patients, the presence of medial posterior-inferior cerebellar artery lesion was associated with good functional outcome (p = 0.030). CONCLUSION: Although the short-term outcome is poorer in LMIpl than LMIpr patients, long-term residual symptoms are more common in LMIpr patients. The location of the LMI and extra-medullary lesion affects the long-term functional outcome of LMIpr and LMIpl patients respectively.

Patterns and Outcomes of the Top of the Basilar Artery Syndrome: The Role of the Posterior Communicating Artery.

BACKGROUND: Clinical syndromes secondary to infarcts in the distal basilar artery (BA) area have been described as "top of the basilar" (TOB) syndrome. However, in the era of advanced imaging technology, it has been realized that the clinical and imaging features are quite diverse in patients with distal BA occlusion. The aim of the present study was to investigate the patterns and clinical outcomes of TOB assessed with modern images and categorize TOBs accordingly. Additionally, we examined the possible influence of the posterior communicating artery (PcoA) on the patterns of TOB. METHODS: Patients with distal BA occlusion on magnetic resonance angiography were categorized as TOB-A, and those with multiple lesions in the distal BA territory on diffusion-weighted magnetic resonance imaging as TOB-L. Patients with angiographically and lesion distribution-defined TOB were classified as having TOB-A&L; those with angiographically defined TOB as having TOB-A without TOB-L; and those with lesion distribution-defined TOB as having TOB-L without TOB-A. The PcoA was categorized as "textbook-type" (good P1) and "fetal-type" (absent P1). Factors associated with unfavorable short-term outcomes (modified Rankin Scale 5-6 at discharge), and 1-year and long-term mortalities, were assessed. RESULTS: Of 1,466 patients with ischemic stroke in the posterior circulation who were admitted to Asan Medical Center within 24 h of symptom onset, 124 (8.5%) had TOB, including 45 with TOB-A&L, 44 with TOB-A, and 35 with TOB-L. NIHSS scores (21 [9.5-26] vs. 6 [3-11.5] vs. 6 [3-9]; p < 0.01) and rates of motor deficit (75.6 vs. 54.5 vs. 34.4%; p < 0.01), concomitant pontine lesions (17.8 vs. 25.0 vs. 2.9%; p < 0.01), PcoA presence (44.4 vs. 68.2 vs. 25.7%; p < 0.01), and unfavorable short-term outcomes (62.2 vs. 25.0 vs. 14.3%; p < 0.01) differed significantly in the 3 patient groups. Multivariate analysis showed that textbook-type PcoA was independently associated with a lower frequency of unfavorable short-term outcomes (OR 0.15, 95% CI 0.03-0.70). Reperfusion therapy (hazard ratio [HR] 0.25, 95% CI 0.07-0.89) and the presence of textbook-type PcoA (HR 0.20, 95% CI 0.05-0.90) were associated with a lower 1-year mortality rate after stroke. CONCLUSION: Patterns and clinical outcomes of TOB vary and are affected by the hemodynamic status of the arterial system, such as BA recanalization and the presence of textbook-type PcoA.

The Impact of Cerebral Atherosclerosis According to Location on Prognosis after Coronary Artery Bypass Grafting.

BACKGROUND: In the previous prospective observational study, we found that cerebral atherosclerosis is an independent predictor of acute stroke after coronary artery bypass grafting (CABG). However, it is unknown whether intracranial cerebral atherosclerosis (ICAS) is important as much as extracranial cerebral atherosclerosis (ECAS) in estimating the risk of post-CABG adverse events. Extending the previous study, we aimed to investigate the immediate and long-term prognostic value of the location of cerebral atherosclerosis in CABG patients. METHODS: This follow-up study of previously reported prospective cohort included 1,367 consecutive patients who received CABG between 2004 and 2007. All patients underwent preoperative magnetic resonance angiography (MRA) to assess intracranial and ECAS, both defined by significant steno-occlusion (≥50%). Participants were classified into 4 groups according to the location of cerebral atherosclerosis: no cerebral atherosclerosis, ECAS only, ICAS only, and ECAS + ICAS. Post-CABG stroke within 14 days (immediate outcome) and mortality (long-term outcome) following CABG were compared between the groups. Survival data for all participants through June 2016 were obtained from the Korean National Registry of Vital Statistics. The Cox proportional hazards model was used to estimate the hazard ratio (HR) of post-CABG stroke and mortality; patients lacking cerebral atherosclerosis were defined as the reference group. RESULTS: The median follow-up duration after CABG was 9.2 years (interquartile range 8.4-10.2 years). Of the participants, 278 (20.3%) patients had ICAS only, while 269 (19.7%) and 347 (25.4%) showed ECAS only and ECAS + ICAS, respectively, in their preoperative MRA. Having ICAS only (HR 5.07; 95% CI 1.37-18.75; p = 0.015) and having ECAS + ICAS (HR 8.43; 95% CI, 2.48-28.61; p = 0.001) independently predicted the immediate stroke, whereas being with ECAS only did not (HR 1.71; 95% CI 0.35-8.50; p = 0.509). Conversely, ICAS-only status was not independently associated with long-term mortality (HR 1.22; 95% CI 0.90-1.65; p = 0.207), whereas ECAS-only status (HR 1.42; 95% CI 1.05-1.90; p = 0.021) and ECAS + ICAS status (HR 1.58; 95% CI 1.20-2.07; p = 0.001) showed independent associations. CONCLUSIONS: Over 10 years of follow-up, cerebral atherosclerosis significantly associated with the development of adverse outcomes after CABG. The prognostic value of ICAS might be different from that of ECAS; immediate post-CABG stroke was more closely associated with ICAS, whereas there was a closer association between long-term post-CABG mortality and ECAS.