The 2022 FASEB Virtual Catalyst Conference on the Cardiac Interatrial Septum and Stroke Risk, December 7, 2022.

There is emerging evidence that the cardiac interatrial septum has an important role as a thromboembolic source for ischemic strokes. There is little consensus on treatment of patients with different cardiac interatrial morphologies or pathologies who have had stroke. In this paper, we summarize the important background, diagnostic, and treatment considerations for this patient population as presented during the Federation of American Societies for Experimental Biology (FASEB) Virtual Catalytic Conference on the Cardiac Interatrial Septum and Stroke Risk, held on December 7, 2022. During this conference, many aspects of the cardiac interatrial septum were discussed. Among these were the embryogenesis of the interatrial septum and development of anatomic variants such as patent foramen ovale and left atrial septal pouch. Also addressed were various mechanisms of injury such as shunting physiologies and the consequences that can result from anatomic variants, as well as imaging considerations in echocardiography, computed tomography, and magnetic resonance imaging. Treatment options including anticoagulation and closure were addressed, as well as an in-depth discussion on whether the left atrial septal pouch is a stroke risk factor. These issues were discussed and debated by multiple experts from neurology, cardiology, and radiology.

Obesity paradox and stroke outcomes according to stroke subtype: a propensity score-matched analysis.

OBJECTIVE: Obesity has traditionally been considered a risk factor for ischemic stroke. However, some clinical observations have reported a complex relationship between patients who are overweight or obese with paradoxically better stroke outcomes. Stroke subtypes have differing distributions of risk factors, so this study aimed to explain the relationship between body mass index (BMI) and functional prognosis according to stroke subtype. METHODS: A prospective institutional database on stroke was accessed between March 2014 and December 2021, and consecutive patients with ischemic stroke were retrospectively selected. BMI was categorized into five groups (underweight, normal weight, overweight, obese, and morbid obesity). The outcome of interest in this study was the modified Rankin Scale (mRS) at 90 d, which was divided into favorable (mRS = 0-2) and unfavorable (mRS ≥ 3) groups. The relationship between functional outcome and BMI was analyzed according to stroke subtype. RESULTS: Among 2779 patients with stroke, 913 (32.9%) had unfavorable outcomes. After a propensity score-matched analysis, obesity was inversely associated with unfavorable outcomes (adjusted odds ratio [aOR] = 0.61, 95% confidence interval [95% CI]: 0.46-0.80) in all patients with stroke. Among the stroke subtypes, overweight (aOR = 0.38, 95% CI: 0.20-0.74) and obese (aOR = 0.40, 95% CI: 0.21-0.76) groups were inversely associated with unfavorable outcomes in the cardioembolism subtype. Obesity (aOR = 0.55, 95% CI: 0.32-0.95) was inversely associated with unfavorable outcomes in the small vessel disease subtype. There was no significant relationship between stroke outcome and BMI classification in the large artery disease subtype. CONCLUSIONS: These findings suggest that the obesity paradox in ischemic stroke outcomes might differ according to the stroke subtype.

Incidence and risk of stroke in Korean patients with congenital heart disease.

OBJECTIVES: The incidence and risk of ischemic stroke (IS) and hemorrhagic stroke (HS) in Korean patients with CHD have not been reported, therefore, we aimed to investigate this. MATERIALS AND METHODS: Participants were selected from the Korean National Health Insurance Service benefit records from 2006-2017. Cases were extracted using diagnosis codes related to CHD. Controls without CHD were selected through age- and sex-matched random sampling at a 1:10 ratio. RESULTS: The case and control groups included 232,203 and 3,024,633 participants, respectively. The median (interquartile range) follow-up period was 7.28 (3.59-8.73) years. The incidence rates of IS and HS per 100,000 person-years were much higher in cases than in controls (IS: 135 vs. 47; HS: 41.7 vs. 24.9). After adjusting for confounders, CHD was a risk factor for IS and HS (subdistribution HR; 1.96 and 1.71, respectively). In patients with CHD, the following risk factors were identified: diabetes, heart failure, and atrial fibrillation for any stroke; hypertension, atrial septal defects, and use of antiplatelet agents for IS only; and coronary artery bypass graft surgery for HS only. CONCLUSIONS: Korean patients with CHD have a high risk of stroke. A personalized preventive approach is needed to reduce the incidence of stroke in this population.

Predicting Stenosis Aggravation in Follow-Up High-Resolution Magnetic Resonance Images of Patients with Intracranial Atherosclerosis.

BACKGROUND: High-resolution magnetic resonance imaging (HRMRI) can provide information on the histopathological characteristics of intracranial atherosclerotic lesions causing arterial stenosis; however, its clinical application in intracranial atherosclerosis lacks standardization for predicting stenosis. Therefore, this study investigated the characteristics of HRMRI that can predict progression based on comparisons of follow-up HRMRI. METHODS: We retrospectively enrolled patients who underwent HRMRI within 7 days of symptom onset to evaluate the characteristics associated with intracranial stenotic lesions. Among them, patients diagnosed with severe stenosis due to atherosclerosis and who underwent follow-up HRMRI 12-24 months after initial HRMRI were included in the final study. We analyzed distinct features, such as stenosis aggravation, the presence of initial plaque enhancement, increment of plaque enhancement, the existence of both eccentric and concentric plaques, and the presence of initial intraplaque hematoma on initial and follow-up HRMRI. RESULTS: Among 442 patients who underwent HRMRI for severe stenosis due to atherosclerosis, 35 underwent follow-up HRMRI 12-24 months later. Patients with stenosis aggravation showed a higher incidence of plaque enhancement (87.5% vs. 3.7%, p < 0.001) and the presence of both concentric and eccentric plaques (75.0% vs. 11.1%; p = 0.001). The area under the curve for the increment of plaque enhancement was 0.92 (95% confidence interval [CI] 0.78-1.00, p ≤ 0.001), while that for the presence of both concentric and eccentric plaques was 0.82 (95% CI 0.63-1.00, p < 0.007). CONCLUSIONS: The presence of both concentric and eccentric plaques and an increase in plaque enhancement were the strongest predictors of aggravation of intracranial artery stenosis.

An Entropy Analysis-Based Window Size Optimization Scheme for Merging LiDAR Data Frames.

LiDAR is a useful technology for gathering point cloud data from its environment and has been adapted to many applications. We use a cost-efficient LiDAR system attached to a moving object to estimate the location of the moving object using referenced linear structures. In the stationary state, the accuracy of extracting linear structures is low given the low-cost LiDAR. We propose a merging scheme for the LiDAR data frames to improve the accuracy by using the movement of the moving object. The proposed scheme tries to find the optimal window size by means of an entropy analysis. The optimal window size is determined by finding the minimum point between the entropy indicator of the ideal result and the entropy indicator of the actual result of each window size. The proposed indicator can describe the accuracy of the entire path of the moving object at each window size using a simple single value. The experimental results show that the proposed scheme can improve the linear structure extraction accuracy.

Atherosclerotic Burden and Vascular Risk in Stroke Patients With Atrial Fibrillation.

Background and Purpose: Data on the effect on vascular outcomes of concomitant atherosclerotic vascular disease (ASVD) with atrial fibrillation (AF) after stroke are limited. This study evaluated the effect of ASVD with AF versus AF only on the risk of vascular events. Methods: We retrospectively analyzed a prospectively registered multicenter database involving 3213 stroke patients with AF. ASVD included extracranial atherosclerosis measured in the proximal portion of the internal carotid artery, intracranial atherosclerosis (all ≥50% stenosis), coronary artery disease, and peripheral artery disease and was categorized into 4 strata depending on the number of ASVDs (0, 1, 2, and 3­4). The independent associations of ASVD with major adverse cardiovascular events, stroke, and all-cause death were assessed. Results: A total of 2670 patients were included (mean age, 73.5±9.8 years; median CHA2DS2-VASc score, 5; interquartile range, 4−6). During the follow-up (mean, 1.7 years), a total of 672 (25.2%) major adverse cardiovascular events, 170 (6.4%) stroke events, and 501 (18.8%) all-cause deaths were noted. The adjusted hazard ratio for major adverse cardiovascular events versus no ASVD was 1.25 (95% CI, 1.00­1.56) for ASVD 1, 1.34 (95% CI, 1.02­1.76) for ASVD 2, and 1.93 (95% CI, 1.24­2.99) for ASVD 3­4. The adjusted hazard ratio for all-cause death versus no ASVD was 1.32 (1.01­1.74), 1.47 (1.06­2.03), and 2.39 (1.47­3.89), respectively. Among ASVD components, the presence of symptomatic or asymptomatic extracranial atherosclerosis was a more potent predictor of major adverse cardiovascular events (1.27 [1.05­1.54]) and all-cause death (1.45 [1.17­1.81]). Conclusions: ASVD burden with AF can be a cumulative marker of a high risk for untoward vascular outcomes. Among ASVD components, extracranial atherosclerosis seems to have a predominant effect.

Pre-Admission CHADS2 and CHA2DS2-VASc Scores on Early Neurological Worsening.

BACKGROUND: Stroke risk scores (CHADS2 and CHA2DS2-VASc) not only predict the risk of stroke in atrial fibrillation (AF) patients, but have also been associated with prognosis after stroke. OBJECTIVE: The aim of this study was to evaluate the relationship between stroke risk scores and early neurological deterioration (END) in ischemic stroke patients with AF. METHODS: We included consecutive ischemic stroke patients with AF admitted between January 2013 and December 2015. CHADS2 and CHA2DS2-VASc scores were calculated using the established scoring system. END was defined as an increase ≥2 on the total National Institutes of Health Stroke Scale (NIHSS) score or ≥1 on the motor NIHSS score within the first 72 h of admission. RESULTS: A total of 2,099 ischemic stroke patients with AF were included. In multivariable analysis, CHA2DS2-VASc score (adjusted odds ratio [aOR] = 1.17, 95% confidence interval [CI] = 1.04-1.31) was significantly associated with END after adjusting for confounders. Initial NIHSS score, use of anticoagulants, and intracranial atherosclerosis (ICAS) were also found to be closely associated with END, independent of the CHA2DS2-VASc score. Multivariable analysis stratified by the presence of ICAS demonstrated that both CHA2DS2-VASc (aOR = 1.20, 95% CI = 1.04-1.38) and CHADS2 scores (aOR = 1.24, 95% CI = 1.01-1.52) were closely related to END in only patients with ICAS. In patients without ICAS, neither of the risk scores were associated with END. CONCLUSIONS: High CHA2DS2-VASc score was associated with END in ischemic stroke patients with AF. This close relationship is more pronounced in patients with ICAS.

Sarcopenia is associated with decreased gray matter volume in the parietal lobe: a longitudinal cohort study.

BACKGROUND: Substantial evidence supports an association between physical activity and cognitive function. However, the role of muscle mass and function in brain structural changes is not well known. This study investigated whether sarcopenia, defined as low muscle mass and strength, accelerates brain volume atrophy. METHODS: A total of 1284 participants with sarcopenic measurements and baseline and 4-year follow-up brain magnetic resonance images were recruited from the Korean Genome and Epidemiology Study. Muscle mass was represented as appendicular skeletal muscle mass divided by the body mass index. Muscle function was measured by handgrip strength. The low mass and strength groups were defined as being in the lowest quintile of each variable for one's sex. Sarcopenia was defined as being in the lowest quintile for both muscle mass and handgrip strength. RESULTS: Of the 1284 participants, 12·6%, 10·8%, and 5·4% were classified as the low mass, low strength, and sarcopenia groups, respectively. The adjusted mean changes of gray matter (GM) volume during 4-year follow-up period were - 9·6 mL in the control group, whereas - 11·6 mL in the other three groups (P < 0·001). The significantly greater atrophy in parietal GM was observed in the sarcopenia group compared with the control group. In a joint regression model, low muscle mass, but not muscle strength, was an independent factor associated with a decrease of GM volume. CONCLUSIONS: Sarcopenia is associated with parietal GM volume atrophy, in a middle-aged population. Maintaining good levels of muscle mass could be important for brain health in later adulthood.

Reperfusion Therapy in Acute Ischemic Stroke with Active Cancer: A Meta-Analysis Aided by Machine Learning.

OBJECTIVES: While the prevalence of active cancer patients experiencing acute stroke is increasing, the effects of active cancer on reperfusion therapy outcomes are inconclusive. Thus, we aimed to compare the safety and outcomes of reperfusion therapy in acute stroke patients with and without active cancer. MATERIALS AND METHODS: A comprehensive literature search was conducted for studies comparing the effects of intravenous thrombolysis (IVT) or endovascular treatment (EVT) in ischemic stroke patients with and without active cancer. The literature was screened using both a manual and machine learning algorithm approach. The outcomes evaluated were symptomatic intracerebral hemorrhage (sICH), all-type intracerebral hemorrhage (aICH), successful recanalization, favorable outcomes (modified Rankin Scale, 0-2), and mortality. We calculated the pooled odds ratio (OR) and 95% confidence interval (CI) using the random-effects model from the included studies. RESULTS: Seven studies were analyzed in this meta-analysis. IVT (n = 1012) was associated with an increased risk of sICH (OR, 9.80; 95% CI, 3.19-30.13) in the active cancer group. However, no significant differences in aICH, favorable outcomes, and mortality were found between groups. Although sICH and successful recanalization in the EVT group (n = 2496) were similar, we observed fewer favorable outcomes (OR, 0.55; 95% CI, 0.33-0.93) and a high prevalence of mortality (OR, 2.91; 95% CI, 1.89-4.47) in the active cancer group. CONCLUSIONS: Reperfusion therapy may benefit selected patients with acute ischemic stroke with active cancer, considering the comparable clinical outcomes of IVT and procedure-related outcomes of EVT. These results should be cautiously interpreted and confirmed in future well-designed large-scale studies.

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.

Positional headache induced by isolated middle cerebral artery dissection: Two case reports.

BACKGROUND: Isolated middle cerebral artery dissection is uncommon and occurs in patients reporting headaches as the only symptom. This makes intracranial artery dissection challenging to diagnose and treat.Case description: We describe two cases of positional headache caused by isolated middle cerebral artery dissection, confirmed using high-resolution magnetic resonance imaging. The two patients presented with sudden-onset headache, occurring when lying in the lateral decubitus position. When lying down in the decubitus position ipsilateral to the intracranial artery dissection, the headache aggravated and middle cerebral artery flow velocity increased on transcranial Doppler ultrasonography compared to when in the supine position. Both patients were treated with antiplatelet agents, and the headache completely resolved within 1-2 weeks. CONCLUSION: We recommend additional imaging studies evaluating intracranial artery dissection as a cause of positional headache.

Intramural Hematoma Shape and Acute Cerebral Infarction in Intracranial Artery Dissection: A High-Resolution Magnetic Resonance Imaging Study.

BACKGROUND: Intracranial artery dissection (IAD) is gaining recognition as an important cause of stroke, but limited information is available about the morphology of the dissection. This study aimed to investigate the relationship between acute cerebral infarctions and the shape of hematoma in patients with IADs using high-resolution magnetic resonance imaging (HRMRI). METHODS: We enrolled consecutive patients who presented with vascular headaches, transient ischemic attacks, or ischemic strokes with acute IAD confirmed by HRMRI using key pathognomonic radiological findings of IAD, including intimal flap, intramural hematoma (IMH), and double lumen. All patients were enrolled and HRMRI was performed, both within 7 days of symptom onset. All patients with acute ischemic infarction within 7 days were enrolled. Patients were divided into 2 groups: those with a proximal dominant intramural hematoma (PIMH) and those with a distal dominant intramural hematoma (DIMH). A PIMH was defined as when the volume of the hematoma in the proximal region was greater than that in the distal region, and a DIMH was defined as when the distal region was greater than that in the proximal region. Clinical and radiological characteristics between the 2 groups were compared using univariable and multivariable logistic regression. RESULTS: The mean age of the 42 participants was 52.6 ± 12.7 years, and 24 (57.1%) were male. Twenty-seven (64.3%) had a PIMH and 15 (35.7%) had a DIMH. Thirty-six (85.7%) showed a double lumen and 27 (64.3%) showed a dissecting flap. Acute infarction was observed in 31 (73.8%) patients. Patients with PIMHs showed a higher prevalence of cerebral infarction than those with DIMHs (96.3 vs. 33.3%; p < 0.001). Univariable (odds ratio [OR] 52.00; 95% confidence interval [CI] 5.386-502.082; p = 0.001) and multivariable (OR 65.43; 95% CI 5.20-822.92; p = 0.001) analyses showed that only dissection type was independently associated with the risk of cerebral infarction. CONCLUSION: In patients with cerebral artery dissections, the shape of IMHs was independently associated with cerebral infarction. PIMHs may be more closely associated with cerebral infarctions than DIMHs.

Cilostazol Mono and Combination Treatments in Ischemic Stroke: An Updated Systematic Review and Meta-Analysis.

Background and Purpose- We performed a systematic review and meta-analysis to explore the efficacy and safety of cilostazol as a mono or combination (plus aspirin or clopidogrel) treatments compared to conventional single antiplatelet therapy (SAPT, mainly aspirin) for secondary stroke prevention. Methods- Randomized controlled trial studies were searched across multiple comprehensive databases (MEDLINE, EMBASE, and Cochrane) for review. The primary outcome was recurrent stroke comprising ischemic and hemorrhagic stroke. Secondary outcomes included ischemic stroke, hemorrhagic stroke, myocardial infarction, and composite outcomes. We performed an updated systematic review and meta-analysis of the identified reports, including 2 recently published randomized controlled trials. In addition, network meta-analysis was performed to compare the relative effects of mono versus combination cilostazol treatments. Results- Ten studies were included in this review, 5 of which were assigned to the cilostazol mono group (n=5429) and the other 5 to the combination group (n=2456). The relative risks of recurrent stroke, ischemic stroke, and composite outcomes with cilostazol mono as well as combination treatments were significantly lower than with SAPT without any significant heterogeneity. An indirect comparison of these 3 outcomes revealed the cilostazol combination approach to be superior. The cilostazol mono treatment diminished hemorrhagic stroke more significantly than SAPT and the cilostazol combination did not increase hemorrhagic stroke compared to SAPT. The outcomes from the 2 cilostazol regimens were comparable to SAPT in the case of myocardial infarction. Conclusions- Cilostazol is a more effective and safer treatment option than SAPT approaches using mainly aspirin. Cilostazol regimens can also be modified to clinical situations as this drug reduces recurrent and ischemic stroke more efficiently as a combination therapy but is more beneficial for hemorrhagic stroke as a monotherapy.

Using the Region of Interest from Time-of-Flight Magnetic Resonance Angiography to Differentiate Between Intracranial Arterial Dissection and True Atherosclerotic Stenosis.

BACKGROUND: Noncontrast three-dimensional time-of-flight magnetic resonance angiography (3D TOF MRA) is commonly used to examine intracranial arterial stenosis, although it can be difficult to identify the etiology of the stenosis. Our aim was to determine the effectiveness of 3D TOF MRA in differentiating an intracranial arterial dissection from atherosclerosis. METHODS: During 2015-2017, 356 patients had confirmed intracranial arterial stenosis based on high resolution-magnetic resonance imaging. This study ultimately included 51 patients with severe focal stenosis that was caused by dissection and atherosclerosis. We compared the dissection group with the atherosclerotic narrowing group by measuring the region-of-interest (ROI) values 3 mm proximal and 3 mm distal from sites of severe focal stenosis. RESULTS: A significant difference was observed between the median ROI difference values in the dissection group (n = 18) and the atherosclerosis group (n = 33; 35.6 [20.9-78.4] vs. 165.5 [99.8-328.5]; p < 0.001). A receiver operating characteristic curve was prepared to distinguish between dissection and atherosclerosis using the ROI difference values. The area under the curve was 0.919 (sensitivity 75.8%, specificity 94.4%). The optimal cutoff value for using ROI to distinguish between dissection and atherosclerosis was found to be 99.0 based on the Youden's index. CONCLUSION: The ROI difference value from 3D TOF MRA could help distinguish between dissection and atherosclerosis. If the ROI difference value from 3D TOF MRA is small (< 99.0), detailed testing should be performed to identify dissection.

Posterior circulation involvement and collateral flow pattern in moyamoya disease with the RNF213 polymorphism.

PURPOSE: Moyamoya disease is a chronic cerebrovascular disorder characterized by progressive stenosis of the circle of Willis with a compensatory collateral vessel network. Recent studies have identified the ring finger protein 213 gene (RNF213) as the unique susceptibility gene for moyamoya disease. The purpose of this study was to compare clinical features of moyamoya disease, especially angiographic findings, between patients with and without the RNF213 mutation. METHODS: Blood samples from 35 patients with moyamoya disease were obtained between May 2016 and May 2017. Information on age at the time of diagnosis, sex, and initial symptom were obtained via retrospective chart review. Angiographic records were evaluated. RESULTS: RNF213 variants were detected in the 28 of 35 patients (80%), including all pediatric patients (100%) and 18 of 25 adult patients (72%) in our cohort. Leptomeningeal collateral flow from posterior to anterior circulation was more frequent in the RNF213-negative group than in the RNF213-positive group (100% versus 38.9%; p = 0.020). Posterior cerebral arterial territorial involvement was more frequently observed in RNF213-positive patients than in RNF213-negative patients (50% versus 0%; p = 0.027). CONCLUSIONS: RNF213 may play a significant role in the development of collateral anastomoses.

Relationship between the Angle of the Posterior Inferior Cerebellar Artery and Cardioembolic Stroke.

BACKGROUND: In patients with unilateral posterior inferior cerebellar artery (PICA) territory infarction, the absence of relevant vessel stenosis may make it difficult to determine the etiology of the infarction. The incidence of cardioembolic (CE) infarction and the factors associated with infarction in such patients remains largely unknown. We hypothesized that the PICA angle would affect the flow direction of embolic sources. Thus, we analyzed the association between high-risk CE sources and the PICA angle. METHODS: Patients with an isolated unilateral PICA territory infarction without relevant vessel stenosis who were admitted between 2014 and 2017 were included from the Korea University Stroke Registry, which includes data from 3 university hospitals. We classified patients according to the presence of CE sources. For each case, we measured the angle between the vertebral artery (VA) and the proximal PICA. RESULTS: In all, 71 patients met the final study entry criteria. Multivariable analysis showed that the PICA angle was independently associated with the risk of a CE source. The optimal cut-off value using Youden's index was 89°. We classified the PICA shape based on the optimal cut-off value. A CE source was identified in 83.3% of cases in which the PICA angle exceeded 89°. CONCLUSIONS: The angle between the PICA and VA was an independent predictor of unilateral PICA stroke with high-risk CE sources without relevant artery stenosis, suggesting that an angle greater than 89° could be a new image marker for determining the stroke subtype.

Dynamic Computation Offloading Scheme for Drone-Based Surveillance Systems.

Recently, various technologies for utilizing unmanned aerial vehicles have been studied. Drones are a kind of unmanned aerial vehicle. Drone-based mobile surveillance systems can be applied for various purposes such as object recognition or object tracking. In this paper, we propose a mobility-aware dynamic computation offloading scheme, which can be used for tracking and recognizing a moving object on the drone. The purpose of the proposed scheme is to reduce the time required for recognizing and tracking a moving target object. Reducing recognition and tracking time is a very important issue because it is a very time critical job. Our dynamic computation offloading scheme considers both the dwell time of the moving target object and the network failure rate to estimate the response time accurately. Based on the simulation results, our dynamic computation offloading scheme can reduce the response time required for tracking the moving target object efficiently.

Free fatty acid as an outcome predictor of atrial fibrillation-associated stroke.

OBJECTIVE: We investigated whether baseline plasma free fatty acid (FFA) concentration is associated with any (ischemic/hemorrhagic) stroke, ischemic stroke/systemic embolism (ISSE), or ischemic stroke among stroke survivors with atrial fibrillation (A-fib). Moreover, we compared the outcome predictability of FFA with previously adopted models, including the CHADS2 and CHA2 DS2 -VASc scoring systems. METHODS: We analyzed data from 279 stroke patients with A-fib and investigated the association between plasma FFA concentration and outcomes using Cox regression models with competing risk analyses. RESULTS: Median follow-up period was 17.5 months. During the study period, any stroke, ISSE, and ischemic stroke occurred in 22, 21, and 17 patients, respectively. The cumulative risk for any stroke, ISSE, and ischemic stroke were 5.1%, 4.7%, and 4.2% at the end of the first year and 14.8%, 12.1%, and 10.8% at the end of the third year, respectively. After adjusting covariates (model 1), baseline FFA concentration was associated with recurrence of any stroke (hazard ratio [HR] = 1.774, 95% confidence interval [CI] = 1.124-2.801, per 1mEq/l increment of FFA). FFA showed a trend association with ISSE (HR = 1.569, 95% CI = 0.950-2.592) and ischemic stroke (HR = 1.630, 95% CI = 0.967-2.746). In adjusted models including CHADS2 or CHA2 DS2 -VASc score as a covariate, (models 2 and 3) FFA was still shown to be an independent predictor of any stroke and ischemic stroke. There was a significant or trend association between FFA and ISSE. INTERPRETATION: FFA may be a potential biomarker that predicts outcome events in stroke with A-fib along with the CHADS2 and CHA2 DS2 -VASc scoring systems.

Free Fatty Acid Is Associated with Thrombogenicity in Cardioembolic Stroke.

BACKGROUND: Recently, the role of free fatty acids (FFAs) in thromboembolism has re-emerged in the context of cardioembolic stroke. Therefore, we attempted to determine the role of FFAs in embolic risk in various potential sources of cardioembolism (PSCE). We hypothesized that if elevated FFA levels in stroke patients are associated with thrombogenesis, then patients with a well-known high risk of embolic sources would have high FFA levels. METHODS: Data collected from 2 hospital-based stroke registries were analyzed to investigate the association between FFA and PSCE. RESULTS: A total of 2,770 acute stroke patients, including 539 with cardioembolic stroke, were selected for analysis. FFA was an independent predictor for cardioembolism (OR 2.755, 95% CI 2.221-3.417, p < 0.001). Among the PSCE, FFA levels were significantly associated with high risk of atrial fibrillation (AF), valvular heart disease, congestive heart failure with low ejection fraction, left atrial thrombus, left ventricular thrombus, left atrial smoke, and ventricular wall motion abnormality. FFA levels increased with the number of PSCE per patient without interaction with the presence of AF. CONCLUSIONS: Among acute stroke patients, FFA levels increased in groups with higher risk of cardioembolic stroke irrespective of the presence of AF. These results suggest that enhanced thrombogenicity could be the main mechanism to explain the elevated FFA levels in patients with cardioembolic stroke.

A Mobility-Aware Adaptive Duty Cycling Mechanism for Tracking Objects during Tunnel Excavation.

Tunnel construction workers face many dangers while working under dark conditions, with difficult access and egress, and many potential hazards. To enhance safety at tunnel construction sites, low latency tracking of mobile objects (e.g., heavy-duty equipment) and construction workers is critical for managing the dangerous construction environment. Wireless Sensor Networks (WSNs) are the basis for a widely used technology for monitoring the environment because of their energy-efficiency and scalability. However, their use involves an inherent point-to-point delay caused by duty cycling mechanisms that can result in a significant rise in the delivery latency for tracking mobile objects. To overcome this issue, we proposed a mobility-aware adaptive duty cycling mechanism for the WSNs based on object mobility. For the evaluation, we tested this mechanism for mobile object tracking at a tunnel excavation site. The evaluation results showed that the proposed mechanism could track mobile objects with low latency while they were moving, and could reduce energy consumption by increasing sleep time while the objects were immobile.