Diagnosis Of Cerebrovascular Disease Research Articles

Vascular cognitive impairment and vascular dementia

Vascular dementia is the second-most-common type of dementia. Vascular cognitive impairment is a term encompassing vascular dementia as well as milder forms of pre-dementia cognitive impairment related to vascular damage that do not meet the criteria for a diagnosis of dementia. Early diagnosis of cerebrovascular disease, including silent infarcts and small vessel disease is difficult, but important, as modification of cardiovascular risk factors is the mainstay of management to decrease further insults and deterioration, and maintain the patient’s independence within their family and social unit.

Abstract TP36: Medical Specialty and Training of Physicians Performing Mechanical Thrombectomy for Acute Ischemic Stroke in the U.S

Introduction: We sought to determine the medical specialty and training of U.S. physicians who perform mechanical thrombectomy for stroke. Methods: We analyzed claims between 2009-2015 from a 5% nationally representative sample of Medicare beneficiaries ≥65 years of age. Validated ICD-9-CM diagnosis codes were used to identify hospitalizations for acute ischemic stroke. Mechanical thrombectomy was defined as a physician claim with CPT code 37184 and an accompanying diagnosis of cerebrovascular disease. Medical specialty was identified using the claim’s Medicare provider specialty code. We reviewed public online profiles to ascertain providers’ residency and fellowship training. Statistical analysis involved chi-square tests and kappa statistics. Results: During 77,774 stroke hospitalizations, we identified 555 thrombectomies, of which 341 (61.4%; 95% CI, 57.2-65.5%) were performed by radiologists, 110 (19.8%; 95% CI, 16.6-23.4%) by neurologists, 91 (16.4%; 95% CI, 13.4-19.7%) by neurosurgeons, and 13 (2.3%; 95% CI, 1.3-4.0%) by others such as cardiologists and vascular surgeons. Of the 555 procedures, 367 (66.1%; 95% CI, 62.0-70.1%) were performed by a physician who had completed a dedicated neurointerventional fellowship. There was excellent agreement (91.4%; kappa, 0.86) between Medicare specialty designations and the online profiles of the 350 physicians who performed these 555 procedures. The rate of mechanical thrombectomy rose from 0.62% (95% CI, 0.56-0.68%) before publication of the MR CLEAN trial to 1.45% (95% CI, 1.21-1.72%) after, but there was no significant change after its publication in the distribution of providers’ specialties or the proportion of procedures performed by those with neurointerventional fellowship training (Figure). Conclusions: Most mechanical thrombectomies for stroke in the U.S. are performed by radiologists, neurologists, and neurosurgeons with dedicated neurointerventional fellowship training.

The Effect of Parental Medical History on the Prevalence of Cerebrovascular Diseases in Their Children in an Iranian Population.

Introduction:Still a controversial issue, family history is known as a risk factor for the development of Cerebrovascular Diseases (CVD). In this study, we aimed to evaluate the relationship between parental history and risk of CVD in their offspring in Iranian population.Methods:Isfahan Cohort Study (ICS) included total 6504 healthy participants which were randomly selected through a two-stage cluster sampling method from three districts. The participants were followed prospectively for 10 years. The diagnosis of CVD were confirmed by expert panelist. Clinically validated history of CVD was established for definition of parental history of CVD. Types of history were categorized into paternal, maternal, both parents, and no history.Results:The prevalence of CVD is generally higher among female offspring compared with male ones (P<0.001). The relative risk of CVD with maternal history was not significant (95%CI=0.95–2.29). By adjusted model analysis, history of CVD in both parents affected the risk of CVD in their male children (RR=2.13, P=0.033, 95%CI). By crude model analysis, maternal history of CVD (P=0.047), history of CVD in both parents (P=0.032), and maternal history of hypertension (P=0.005) were determined as risk factors of CVD in offspring. Indeed, the mean age of CVD in offspring decreases based on this order: history of hypertension in parents, paternal history of CVD in both parents, maternal history of CVD, and no history (P<0.001).Conclusion:Early and regular screening for CVD development is necessary in female offspring of the families with the present history of CVD from maternal side. This group are at risk and should be considered as the target group for screening and taking preventive measures.

Semi-Supervised Cerebrovascular Segmentation by Hierarchical Convolutional Neural Network

Due to the tortuosity and the complexity of cerebral vasculature and the similar intensity distribution with the background, it remains challenging to accurately segment cerebral vessels from magnetic resonance angiography (MRA). The previous rule-based methods have limitations when applied to accurate clinical diagnosis, such as the under-segmentation on complex vessels, the dependence on domain knowledge, and the lack of quantification estimation. In this paper, we proposed a semi-supervised cerebrovascular segmentation method with a hierarchical convolutional neural network (H-CNN) that transfers the exquisite model/feature design in rule-based methods to solve the mapping from MRA images to cerebral vessels. First, we generated the tube-level labels of cerebral vessels with centerlines and estimated radii. Second, we constructed and trained an H-CNN with the MRA images and corresponding tube-level labels. Third, the stopping criterion of the proposed H-CNN was determined by the comprehensive index (CI) that was defined based on partially annotated voxel-level ground truth. The comparison of our H-CNN with the vesselness, bi-Gaussian, optimally oriented flux, vessel enhancing diffusion, hybrid diffusion with continuous switch, Mimics software, convolutional neutral network2D (CNN)2D, and CNN3D were conducted on six testing images. The mean sensitivity, accuracy, and the CI of our H-CNN are 94.69%, 97.85%, and 2.99%, respectively, outperforming the other methods. The curved planar reformation also visualized the performance of H-CNN for cerebrovascular segmentation. Given only the tube-level labels, the proposed H-CNN method accomplished the voxel-level vessel segmentation via the hierarchical update of CNN. The H-CNN can potentially to be applied for the accurate diagnosis of cerebrovascular diseases and other medical image segmentation with only partially correct labels.

Factors influencing MRI of Cerebrovascular Disease Patients in Korea

Cerebrovascular disease is the critical cause of death and is important cause of disability worldwide and the leading contributor to the chronic disease burden. Cerebrovascular disease, is also the leading contributor, to the chronic disease burden. In this study, we analyzed the factors affecting MRI, which are critical for the diagnosis of cerebrovascular disease, with high mortality rate, and high medical burden. In the present study, data from the Korean National Hospital Discharge In-depth Injury Survey for three years, from 2012 to 2014, we used. The subjects were 14,383 patients with cerebrovascular disease over 20 years of age who were first diagnosed with the international disease classification code I60-I67: cerebral hemorrhage, cerebral infarction, obstruction and stenosis of the precerebral artery, cerebral aneurysm etc. The analysis revealed the independent variables affecting MRI examination of cerebrovascular diseases were sex, age, type of insurance, admission route, length of stay, treatment result, location of hospital, and the number of hospital beds..

Mortality and morbidity among hospitalized adult patients with neurological diseases in Cameroon

BackgroundThere is inadequate information on the morbidity and mortality (M&M) from neurological diseases in sub-Saharan Africa. ObjectiveTo record the M&M from neurological diseases in adults in Cameroon from 2013 to 2015 using a registry and surveillance from two urban health care centers. MethodsRecords from all adult admissions from two urban hospitals over a two year period were reviewed. Adult cases with neurological diagnosis as the main cause for admission were identified. The neurological diagnosis was made by a neurologist in all cases. Variables analyzed were: demographics, neurological diagnosis, medical history, medical center characteristics, morbidity and mortality (M&M). Neurological diseases were classified according to ICD-10. ResultsAmong the 2225 neurological admissions of adults, death from neurological disease was recorded in 423 patients (19.01%), and disability in 819 of the survivors (53.6%). The factors that were significantly associated with death in the multivariate analysis were age, history of ischemic cardiac disease, and neurological diagnoses of CNS infection, cerebrovascular disease, and CNS tumor. Similarly, factors associated with disability were medical history of HIV, and cerebrovascular disease, and neurological diagnoses of cerebrovascular disease and CNS tumor. Higher educational level and epilepsy were associated with less disability. ConclusionsAs expected in this sample, older patients with neurological diseases had more M&M. Morbidity was inversely associated with education, which given that cerebrovascular disease is by far the most common cause of morbidity, indicates the power of risk factor control in preventing neurological disability.

Recrudescence of Deficits After Stroke

Reemergence of previous stroke-related deficits (or poststroke recrudescence [PSR]) is an underrecognized and inadequately characterized phenomenon. To investigate the clinical features, triggers, and risk factors for PSR. This retrospective study incorporated a crossover cohort study to identify triggers and a case-control study to identify risk factors. The study used the Massachusetts General Hospital Research Patient Data Repository to identify patients for the period January 1, 2000, to November 30, 2015, who had a primary or secondary diagnosis of cerebrovascular disease, who underwent magnetic resonance imaging of the brain at least once, and whose inpatient or outpatient clinician note or discharge summary stated the term recrudescence. In all, 153 patients met the preliminary diagnostic criteria for PSR: transient worsening of residual poststroke focal neurologic deficits or transient recurrence of prior stroke-related focal deficits, admission magnetic resonance imaging showing a chronic stroke but no acute infarct or hemorrhage, no evidence of transient ischemic attack or seizure, no acute lesion on diffusion-weighted imaging, and no clinical or electroencephalographic evidence of seizure around the time of the event. Clinical and imaging features of PSR; triggers (identified by comparing PSR admissions with adjacent admissions without PSR); and risk factors (identified by comparing PSR cases with control cases from the Massachusetts General Hospital Stroke Registry). Of the 153 patients, 145 had prior infarct, 8 had hypertensive brain hemorrhage, and 164 admissions for PSR were identified. The patients' mean (SD) age was 67 (16) years, and 92 (60%) were women. Recrudescence occurred a mean (SD) of 3.9 (0.6) years after the stroke, lasted 18.4 (20.4) hours, and was resolved on day 1 for 91 of the 131 episodes with documented resolution time (69%). Deficits were typically abrupt and mild and affected motor-sensory or language function. No patient had isolated gaze paresis, hemianopia, or neglect. During PSR, the National Institutes of Health Stroke Scale (NIHSS) score worsened by a mean (SD) 2.5 (1.9) points, and deficits were limited to a single NIHSS item in 62 episodes (38%). The underlying chronic strokes were variably sized, predominantly affected white matter tracts, and involved the middle cerebral artery territory for 112 patients (73%). Infection, hypotension, hyponatremia, insomnia or stress, and benzodiazepine use were higher during PSR admissions. Compared with the control group (patients who did not experience recrudescence), the PSR group (patients who were hospitalized for recrudescence) had more women, African American individuals, and those who self-identified as being from "other" race. The PSR group also had more diabetes, dyslipidemia, smoking, infarcts from small-vessel disease, and "other definite" causes and worse onset NIHSS scores. Six patients (4%) received intravenous tissue plasminogen activator without complications. The PSR features identified in the study should enable prompt diagnosis and distinguish recrudescence from mimics, such as transient ischemic attacks, migraine, Todd paralysis, and Uhthoff phenomenon. Prospective studies are required to validate the proposed diagnostic criteria and to decipher underlying mechanisms.

Asymptomatic carotid artery stenosis and retinal nerve fiber layer thickness. A community-based, observational study.

PurposeTo examine whether an abnormally thin retinal nerve fiber layer (RNFL) is associated with cerebrovascular insufficiency.DesignCommunity-based study.MethodsThe Asymptomatic Polyvascular Abnormalities in Community Study included Chinese aged 40+ years and without histories of cerebrovascular incidents or coronary heart disease. Using transcranial Doppler and carotid duplex ultrasound examination, we assessed presence and degree of an intracranial arterial stenosis (ICAS) and extracranial carotid arterial stenosis (ECAS) and we measured the RNFL thickness by spectral-domain optical coherence tomography.ResultsThe study included 3,376 participants with a mean age of 54.3±10.3 years. Thinner RNFL was significantly correlated with a higher prevalence of ECAS (P = 0.035; standardized regression coefficient beta:-0.04; non-standardized regression coefficient B:-0.99; 95% confidence intervals(CI):-1.90,-0.07), after adjusting for age (P<0.001;beta:-0.25;B:-0.26;95%CI:-0.30,-0.22), gender (P = 0.001;beta:-0.07;B:-1.36;95%CI:-2.14,-0.58) and blood concentration of low-density lipoproteins (P = 0.03;beta:0.04;B:0.52;95%CI:0.05,0.98). In a reverse manner, prevalence of ECAS was associated with a thinner RNFL thickness (P = 0.007; odds ratio (OR):0.99; 95%CI:0.98,0.99) after adjusting for older age (P<0.001;OR:1.06;95%CI:10.05,10.7), higher prevalence of ICAS (P = 0.01;OR:1.34;95%CI:1.07,1.69) and higher prevalence of carotid artery plaques (P<0.001;OR:9.18;95%CI:6.93,12.2), and higher blood concentration of total cholesterol (P = 0.03;OR:1.12;95%CI:1.01,1.23). In univariate analysis, an increasing degree of ECAS was significantly correlated with a thinner RNFL.ConclusionsHigher prevalence and degree of ECAS were correlated with thinner RNFL and vice versa. Patients with abnormally thin RNFL without ocular disease may undergo carotid artery examination to detect asymptomatic carotid artery stenosis. Examination of the RNFL is useful for the diagnosis of cerebrovascular disease.

Classification of transcranial Doppler signals using individual and ensemble recurrent neural networks

Transcranial Doppler (TCD) is a reliable technique with the advantage of being non-invasive for the diagnosis of cerebrovascular diseases using blood flow velocity measurements pertaining to the cerebral arterial segments. In this study, the recurrent neural network (RNN) is used to classify TCD signals captured from the brain. A total of 35 real, anonymous patient records are collected, and a series of experiments for stenosis diagnosis is conducted. The extracted features from the TCD signals are used for classification using a number of RNN models with recurrent feedbacks. In addition to individual RNN results, an ensemble RNN model is formed in which the majority voting method is used to combine the individual RNN predictions into an integrated prediction. The results, which include the accuracy, sensitivity, and specificity rates as well as the area under the Receiver Operating Characteristic curve, are compared with those from the Random Forest Ensemble model. The outcome positively indicates the usefulness of the RNN ensemble as an effective method for detecting and classifying blood flow velocity changes due to brain diseases.

Effect of health insurance on direct hospitalisation costs for in-patients with ischaemic stroke in China

Objectives The aim of the present study was to determine the direct medical costs of hospitalisations for ischaemic stroke (IS) in-patients with different types of health insurance in China and to analyse the demographic characteristics of hospitalised patients, based on data supplied by the China Health Insurance Research Association (CHIRA). Methods A nationwide and cross-sectional sample of IS in-patients with International Classifications of Diseases 10th Revision (ICD-10) Code I63 who were ensured under either the Basic Medical Insurance Scheme for Employees (BMISE) or the Basic Medical Insurance Scheme for Urban Residents (BMISUR) was extracted from the CHIRA claims database. A retrospective analysis was used with regard to patient demographics, total hospital charges and costs. Results Of the 49588 hospitalised patients who had been diagnosed with IS in the CHIRA claims database, 28850 (58.2%) were men (mean age 67.34 years) and 20738 (41.8%) were women (mean age 69.75 years). Of all patients, 40347 (81.4%) were insured by the BMISE, whereas 8724 (17.6%) were insured by the BMISUR; the mean age of these groups was 68.55 and 67.62 years respectively. For BMISE-insured in-patients, the cost per hospitalisation was RMB10131 (95% confidence interval (CI) 10014-10258), the cost per hospital day was RMB787 (95% CI 766-808), the out-of-pocket costs per patient were RMB2346 (95% CI 2303-2388) and the reimbursement rate was 74.61% (95% CI 74.48-74.73%). For BMISUR-insured in-patients the cost per hospitalisation was RMB7662 (95% CI 7473-7852), the cost per hospital day was RMB744 (95% CI 706-781), the out-of-pocket costs per patient were RMB3356 (95% CI 3258-3454) and the reimbursement rate was 56.46% (95% CI 56.08-56.84%). Conclusions Costs per hospitalisation, costs per hospital day and the reimbursement rate were higher for BMISE- than BMISUR-insured in-patients, but BMISE-insured patients had lower out-of-pocket costs. The financial burden was higher for BMISUR- than BMISE-insured in-patients. For BMISUR-insured in-patients, the out-of-pocket payment was 43.54% of total expenses, which means the government should increase the financial investment, raise reimbursement rates and set up differential reimbursements to meet the health needs of in-patients with different income levels. What is known about the topic? Cardiovascular and cerebrovascular diseases are major non-communicable diseases affecting the health of the Chinese population. The China Health Statistics Yearbook (2013) reported that across all in-patients, 195million (5.82%) had been discharged with a diagnosis of cerebrovascular disease. Of these, 118million had IS, accounting for 60.51% of all in-patients with cerebrovascular disease and 54.97% of hospitalisation costs for all cerebrovascular disease in-patients. After the two basic insurance systems, namely the BMISE and BMISUR, had been established, the out-of-pocket expenses for patients were reduced. However, to date there have been no studies investigating how the different types of health insurance (i.e. the BMISE and the BMISUR) affected the costs of treatment of IS in-patients in China. What does this paper add? This paper reports the direct costs for patients diagnosed with IS based on data supplied by the CHIRA. Direct hospitalisation costs depending on the type of insurance cover, age and gender were also evaluated. What are the implications for practitioners? The present study found that the personal financial burden of disease treatment was higher for in-patients insured under the BMISUR than BMISE. For in-patients insured under the BMISUR, the out-of-pocket payment was 43.54% of total expenses, which means the government should increase the financial investment, raise reimbursement rates and set up differential reimbursement rates to meet the health needs of patients with different incomes.

Reliability of the minimum basic dataset for diagnoses of cerebrovascular disease

IntroductionThe minimum basic dataset is the largest available hospital care administrative database that is used in clinical studies and hospital management in association with diagnosis-related groups (DRGs). In 2011, the quality of the national MBDS in hospital discharges was audited, in order to assess its reliability. This paper presents a sub-analysis of the results from that analysis which are referred to cerebrovascular disease (CVD). MethodsUsing all discharge reports from the Spanish MBDS in 2009, a representative sample was obtained by stratified sampling and 11209 records were evaluated. Outcome indicators were obtained to measure any differences observed between the national MBDS being evaluated and the hospital's original MBDS. Analysis of codes for CVD as a primary diagnosis was performed for ICD-9-CM diagnostic categories 430 through 438. We evaluated error rates in the selection and classification of main diagnoses, as well as in DRG assignment. ResultsThere were 397 discharges of cases of CVD which included 21 different DRGs. Diagnostic coding showed a concordance rate of 81.87%; the selection error rate was 2.26% and the classification error rate was 15.87%. The error rate in the DRG was 16.12% and associated with the greatest impact on the mortality risk level. ConclusionsWhile the errors we observed must be taken into account, data suggest that the quality of the MBDS for CVD is sufficient to ensure delivery of valid information. The hospital discharge registry serves as a valuable tool for use in studies of this disease.

Gap-free segmentation of vascular networks with automatic image processing pipeline

Current image processing techniques capture large vessels reliably but often fail to preserve connectivity in bifurcations and small vessels. Imaging artifacts and noise can create gaps and discontinuity of intensity that hinders segmentation of vascular trees. However, topological analysis of vascular trees require proper connectivity without gaps, loops or dangling segments. Proper tree connectivity is also important for high quality rendering of surface meshes for scientific visualization or 3D printing. We present a fully automated vessel enhancement pipeline with automated parameter settings for vessel enhancement of tree-like structures from customary imaging sources, including 3D rotational angiography, magnetic resonance angiography, magnetic resonance venography, and computed tomography angiography. The output of the filter pipeline is a vessel-enhanced image which is ideal for generating anatomical consistent network representations of the cerebral angioarchitecture for further topological or statistical analysis. The filter pipeline combined with computational modeling can potentially improve computer-aided diagnosis of cerebrovascular diseases by delivering biometrics and anatomy of the vasculature. It may serve as the first step in fully automatic epidemiological analysis of large clinical datasets. The automatic analysis would enable rigorous statistical comparison of biometrics in subject-specific vascular trees. The robust and accurate image segmentation using a validated filter pipeline would also eliminate operator dependency that has been observed in manual segmentation. Moreover, manual segmentation is time prohibitive given that vascular trees have more than thousands of segments and bifurcations so that interactive segmentation consumes excessive human resources. Subject-specific trees are a first step toward patient-specific hemodynamic simulations for assessing treatment outcomes.

BILATERAL OCCIPITAL POLE HYPERTENSIVE STROKE DIAGNOSED WITH MACULAR INTEGRITY ASSESSMENT (MAIA) MICROPERIMETRY

To describe the utility of microperimetry testing in the diagnosis of a bilateral occipital stroke. Retrospective case report. A 57-year-old male with hypertension presented with complaints of bilateral blurred central vision and bilateral hypertensive retinopathy with cotton-wool spots. Automated perimetry demonstrated a central scotoma in both eyes that did not respect the vertical midline; however, microperimetry testing revealed a bilateral homonymous hemianopia that suggested cerebrovascular disease which was subsequently confirmed with magnetic resonance imaging. In cases of unexplained central visual loss, microperimetry testing may be a useful ancillary test for the diagnosis of cerebrovascular disease.

Complementary examinations other than neuroimaging and neurosonology in acute stroke.

The etiologic diagnosis of cerebrovascular diseases requires non-routine complementary examinations to be performed. Thus, in specific cases, after neuroimaging (computed tomography/magnetic resonance imaging cerebral scan sequences) and neurosonology (Doppler test of the supra-aortic trunks, transcranial echography and echocardiography), which academically allow us to classify the patients according to their etiologic stroke subtype, further examinations must be used to make a correct etiologic diagnostic. The present review aims to update knowledge about the usefulness of the different tests of blood and urine, plain chest radiography, X-ray of the spine, skull and abdomen, lumbar puncture, electroencephalography, evoked potentials, polysomnography, and pathologic examination after biopsy of the artery, skin, muscles, nerves, meninges, and brain, in the management of patients who have suffered an acute stroke.

A Comparison of Different Algorithms for the Assessment of Cardiovascular Risk in Patients at Waiting List for Kidney Transplantation

BackgroundCardiovascular disease (CVD) is the leading cause of death after renal transplantation with a high prevalence in dialysis patients. It is still a matter of debate how to assess the cardiovascular risk in kidney transplant candidates. Several approaches and scores exist and found their way into the guidelines.Methods and ResultsWe herein assessed PROCAM, Framingham, ESC-SCORE and our own dedicated algorithm in patients applying for renal transplantation at our transplantation center between July 2006 and August 2009. Data of 347 consecutive patients were recorded at baseline and during a follow-up of 4.1 years regarding cardiovascular (CV) events and event-free and overall survival. During follow-up 31 (8.9%) patients died, 24 (6.9%) myocardial infarctions occurred and 19 (5.5%) patients received a new diagnosis of cerebrovascular disease. Predictors for event-free survival identified by univariable Cox regression analysis were age at start of dialysis, ESC-SCORE as well as our own score. Final multivariable model with a stepwise model building procedure revealed age at start of dialysis and smoking to be prognostic for event-free (hazard ratio 1.07/year and 2.15) and overall survival (1.10/year and 3.72).ConclusionComparison of CV risk assessment scores showed that ESC-SCORE most robustly predicted event-free and overall survival in our cohort. We conclude that CV risk assessment by ESC-SCORE can be reasonably performed in kidney transplant candidates.

Low serum miR-320b expression as a novel indicator of carotid atherosclerosis

We aimed to investigate correlation of carotid plaque with serum microRNA level and provide a potential mechanism for ischemic stroke prevention. Fasting serum was obtained from 177 patients with carotid plaques diagnosed using B ultrasound and 155 healthy subjects for RNA extraction and measurement of glucose, lipid and related biochemical indices. microRNAs level was assayed using microarray, validated using real-time PCR and statistically analyzed for their correlation with relevant clinical information. Statistical analyses showed significant differences between control and plaque groups in age, smoking history, and histories of cerebrovascular diseases, blood pressure, diabetes and coronary diseases. Patients in plaque group had significantly higher LDL-C level but significantly lower miR-320b level than healthy subjects. The P50 (P25–P75) of miR-320b was 2.38 (1.46–3.80) in control group and 1.20 (0.80–2.01) in plaque group (P=0.000), as well as 1.39 (0.83–2.08) in stable plaque group and 0.77 (0.590.99) in vulnerable plaque group (P=0.000). The area under the ROC curve of traditional factors, miR320b with traditional factors, traditional factors with plaque diameter, and traditional factors with IMT for patients with carotid plaques was 0.710, 0.834, 0.826 and 0.808, respectively. This study suggests that miR-320b is a specific serum marker of carotid atherosclerosis and vulnerable plaque, and its combination with traditional factors is the best means for diagnosis of cerebrovascular diseases. The carotid atherosclerosis complicated with vulnerable plaque is a high risk factor for cerebral infarction. B-ultrasound examination combined with serum miR-320b expression and traditional indices could be used to predict subjects with high-risk for ischemic stroke.

Selective Arterial Spin Labeling: Techniques and Neurovascular Applications.

Knowledge of the distribution of blood flowing from the heart to the brain-feeding arteries is important for the understanding and diagnosis of cerebrovascular diseases. Due to anatomical variations and anomalies within the cerebrovasculature, together with changes caused by various cerebrovascular diseases, there is high variability in the distribution of blood to the parenchyma. This article reviews the various methods that are available for determining the flow territories of the brain-feeding arteries and provides an overview of the different territorial arterial spin labeling (ASL) magnetic resonance imaging (MRI) techniques that have been introduced during the past 2 decades. ASL is a noninvasive method that uses arterial blood as an endogenous contrast agent by magnetically labeling the inflowing blood with radiofrequency pulses. Several selective ASL MRI methods are available to visualize the perfusion territories of individual brain feeding arteries and determine the presence of collateral blood flow pathways. Clinically, these selective perfusion methods may replace more invasive procedures such as catheter angiography for various diseases in which it is of importance to determine the feeding blood vessels, evaluate the presence potential collateral pathways, and monitor the patency of surgical bypasses.

A Parallel Markov Cerebrovascular Segmentation Algorithm Based on Statistical Model

For segmenting cerebral blood vessels from the time-of-flight magnetic resonance angiography (TOF-MRA) images accurately, we propose a parallel segmentation algorithm based on statistical model with Markov random field (MRF). Firstly, we improve traditional non-local means filter with patch-based Fourier transformation to preprocess the TOF-MRA images. In this step, we mainly utilize the sparseness and self-similarity of the MRA brain images sequence. Secondly, we add the MRF information to the finite mixture mode (FMM) to fit the intensity distribution of medical images. We make use of the MRF in image sequence to estimate the proportion of cerebral tissues. Finally, we choose the particle swarm optimization (PSO) algorithm to parallelize the parameter estimation of FMM. A large number of experiments verify the high accuracy and robustness of our approach especially for narrow vessels. The work will offer significant assistance for physicians on the prevention and diagnosis of cerebrovascular diseases.

Abstract TP186: Lack of Insurance is Associated with Increased Risk of Intracerebral Hemorrhage

Introduction: Effective management of hypertension is essential for the prevention of intracerebral hemorrhage (ICH), but disparities in access to healthcare create a barrier to achieving this aim. Hypothesis: Among patients presenting for emergency care of hypertension, lack of insurance is associated with a higher risk of subsequent ICH. Methods: We performed a retrospective cohort study using administrative data from all acute care hospitalizations and emergency department (ED) visits in California, Florida, and New York between the years of 2005 and 2011. Our cohort comprised patients discharged from the ED with a primary diagnosis of hypertension, defined as International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes 401-405. Patients with a prior or concomitant diagnosis of cerebrovascular disease (ICD-9-CM codes 430-438) were excluded. Patients 65 years and older were excluded because these patients often have access to Medicare insurance. Our predictor variable was lack of insurance, as compared with Medicaid or commercial insurance. Patients were followed for the primary outcome of ICH, defined using previously validated ICD-9-CM codes. Survival statistics were used to calculate the cumulative rate of ICH and Cox proportional hazards analysis was used to assess the association between lack of insurance and development of ICH while adjusting for demographic characteristics and vascular risk factors. Results: Among 361,019 patients with 3.4 (+/- 1.8) years of follow-up, the cumulative rate of ICH in patients without insurance was 1.03% (95% confidence interval [CI], 0.90-1.18%) as compared to 0.88% (95% CI, 0.80-0.96) in patients with insurance. After adjusting for demographic variables and vascular risk factors, lack of insurance was associated with the development of ICH (hazard ratio, 1.20; 95% CI, 1.07-1.34). Conclusion: In a large, heterogeneous group of patients presenting for emergency care of hypertension, lack of insurance was associated with an increased risk of ICH after discharge. Further investigation is needed to address the impact of access to healthcare on rates of this disabling disease.

Automatic recognition of subject-specific cerebrovascular trees.

An image filter designed for reconstructing cerebrovascular trees from MR images is described. Current imaging techniques capture major cerebral vessels reliably, but often fail to detect small vessels, whose contrast is suppressed due to limited resolution, slow blood flow rate, and distortions around bifurcations or nonvascular structures. An incomplete view of angioarchitecture limits the information available to physicians. A novel Hessian-based filter for contrast-enhancement in MR angiography and venography for blood vessel reconstruction without introducing dangling segments is presented. We quantify filter performance with receiver-operating-characteristic and dice-similarity-coefficient analysis. Total extracted vascular length, number-of-segments, volume, surface-to-distance, and positional error are calculated for validation. Reconstruction of cerebrovascular trees from MR images of six volunteers show that the new filter renders more complete representations of subject-specific cerebrovascular networks. Validation with phantom models shows the filter correctly detects blood vessels across all length scales without failing at bifurcations or distorting diameters. The novel filter can potentially improve the diagnosis of cerebrovascular diseases by delivering metrics and anatomy of the vasculature. It also facilitates the automated analysis of large datasets by computing biometrics free of operator subjectivity. The high quality reconstruction enables computational mesh generation for subject-specific hemodynamic simulations. Magn Reson Med 77:398-410, 2017. © 2016 Wiley Periodicals, Inc.