Uncertainty Quantification and Reduction in Cardiac Electrophysiological Imaging

Cardiac electrophysiological (EP) imaging involves solving an inverse problem that infers cardiac electrical activity from body-surface electrocardiography data on a physical domain defined by the body torso. To avoid unreasonable solutions that may fit the data, this inference is often guided by data-independent prior assumptions about different properties of cardiac electrical sources as well as the physical domain. However, these prior assumptions may involve errors and uncertainties that could affect the inference accuracy. For example, common prior assumptions on the source properties, such as fixed spatial and/or temporal smoothness or sparseness assumptions, may not necessarily match the true source property at different conditions, leading to uncertainties in the inference. Furthermore, prior assumptions on the physical domain, such as the anatomy and tissue conductivity of different organs in the thorax model, represent an approximation of the physical domain, introducing errors to the inference. To determine the robustness of the EP imaging systems for future clinical practice, it is important to identify these errors/uncertainties and assess their impact on the solution. This dissertation focuses on the quantification and reduction of the impact of uncertainties caused by prior assumptions/models on cardiac source properties as well as anatomical modeling uncertainties on the EP imaging solution. To assess the effect of fixed prior assumptions/models about cardiac source properties on the solution of EP imaging, we propose a novel yet simple Lp-norm regularization method for volumetric cardiac EP imaging. This study reports the necessity of an adaptive prior model (rather than fixed model) for constraining the complex spatiotemporally changing properties of the cardiac sources. We then propose a multiple-model Bayesian approach to cardiac EP imaging that employs a continuous combination of prior models, each re-effecting a specific spatial property for volumetric sources. The 3D source estimation is then obtained as a weighted combination of solutions across all models. Including a continuous combination of prior models, our proposed method reduces the chance of mismatch between prior models and true source properties, which in turn enhances the robustness of the EP imaging solution. To quantify the impact of anatomical modeling uncertainties on the EP imaging solution, we propose a systematic statistical framework. Founded based on statistical shape modeling and unscented transform, our method quantifies anatomical modeling uncertainties and establish their relation to the EP imaging solution. Applied on anatomical models generated from different image resolutions and different segmentations, it reports the robustness of EP imaging solution to these anatomical shape-detail variations. We then propose a simplified anatomical model for the heart that only incorporates certain subject-specific anatomical parameters, while discarding local shape details. Exploiting less resources and processing for successful EP imaging, this simplified model provides a simple clinically-compatible anatomical modeling experience for EP imaging systems. Different components of our proposed methods are validated through a comprehensive set of synthetic and real-data experiments, including various typical pathological conditions and/or diagnostic procedures, such as myocardial infarction and pacing. Overall, the methods presented in this dissertation for the quantification and reduction of uncertainties in cardiac EP imaging enhance the robustness of EP imaging, helping to close the gap between EP imaging in research and its clinical application

The effect of orem’s self-care model on quality of life of patients with hypothyroid goiter‏

Abstract Background & aim: Hypothyroid goiter, like other chronic diseases, can affect the patients’ quality of life (QOL). This study aimed to examine the effect of Orem’s Self-care Model Application on QOL of patients with hypothyroid goiter. Methods: In this interventional study, 70 patients with hypothyroid goiter referred to healthcare clinics of Yasuj were randomly divided into experimental and control groups (n=35). Data were collected by a questionnaire, evaluating self-care, according to Orem’s Model, and the SF-36 questionnaire, measuring the QOL at baseline and 3 months following intervention. For intervention, patients received Orem’s Self-care instructions adjusted to their self-care needs during eight 45-minute sessions. Data were analyzed by using paired and independent t-tests. Results: In the experimental group, mean of QOL was 43.28±17.26 before and 79.64±11.86 after intervention. Paired t-test showed that the difference between pre and post intervention scores is significant (P=0.001). In the control group, however, there was no significant difference in QOL before and after intervention. After intervention, eight domains of QOL in experimental group were significantly higher than those in the control group. Conclusion: This study revealed that applying Orem’s Self-care Model could improve the quality of life in patients with hypothyroid goiter

-Norm Regularization in Volumetric Imaging of Cardiac Current Sources

Advances in computer vision have substantially improved our ability to analyze the structure and mechanics of the heart. In comparison, our ability to observe and analyze cardiac electrical activities is much limited. The progress to computationally reconstruct cardiac current sources from noninvasive voltage data sensed on the body surface has been hindered by the ill-posedness and the lack of a unique solution of the reconstruction problem. Common L2- and L1-norm regularizations tend to produce a solution that is either too diffused or too scattered to reflect the complex spatial structure of current source distribution in the heart. In this work, we propose a general regularization with Lp-norm () constraint to bridge the gap and balance between an overly smeared and overly focal solution in cardiac source reconstruction. In a set of phantom experiments, we demonstrate the superiority of the proposed Lp-norm method over its L1 and L2 counterparts in imaging cardiac current sources with increasing extents. Through computer-simulated and real-data experiments, we further demonstrate the feasibility of the proposed method in imaging the complex structure of excitation wavefront, as well as current sources distributed along the postinfarction scar border. This ability to preserve the spatial structure of source distribution is important for revealing the potential disruption to the normal heart excitation

Assessing the effect of educational program based on small group on promoting knowledge and health literacy among women with type2 diabetes referring to selected hospitals affiliated to Tehran University of Medical Sciences

Background: Health Literacy is the capacity in which individuals have to obtain, process, and understand basic health information and services needed to make appropriate health decisions. Limited health literacy can reduce adults’ ability to comprehend and adhere treatment plans. This study was designed and implemented to assess effect of health education on promoting knowledge and health literacy in women with type 2 diabetes. Methods: This randomize clinical trial study, was conducted among 160 women with type 2 diabetes, in two experimental and control groups. Tools of current study were a brief form of standard questionnaire (Short Test of Functional Health Literacy in Adults, TOFHLA) and knowledge was measured by self-administrated questionnaire. Intervention in a form of small groups, was performed in 6 educational sessions (45-60minuts) in experimental group. In order to analyzing data, SPSS16 software was used and independent t- test, Kruskal-Wallis, Whitney U Wilcoxon, Co-Variation, Chi- ، square were conducted. Results: Demographic variables of studied population in two groups was similar before intervention (p>0.05). Differences between the scores of Knowledge and Health Literacy in two groups, after and before intervention, was totally different (after, p0/05). Conclusion: Study findings indicated that education with small group's strategy in experimental group, in comparison with current education is effective

Determination of knowledge and health literacy among women with type 2 diabetes in teaching hospitals of TUMS

Background: Health literacy is the degree to which individuals have the capacity to obtain, process, and understanding basic health information and services needed to make appropriate health decisions. The aim of this study was to assess relationship between health literacy and knowledge of women with type 2 diabetes. Materials & Methods: In this cross sectional survey, 160 women with type 2 diabetes were selected by convenience sampling method. Data collected by using a STOHFLA standard questionnaire and knowledge was measured by self-administrated questionnaire. Obtained data analyzed by SPSS16 software in two categories of descriptive and inferential statistics (Chi-square and Pearson coefficient). Results: The mean age of studied population was 52.73±8.56 years old. The means of health literacy and knowledge was 40.57±15.87 and 21.52±2.94, respectively. There was a relation between occupation, education and family history with knowledge and health literacy score, and also between incomes with knowledge. There was reverse significant relation between age and disease duration with knowledge and health literacy. Conclusion: Results indicated that patients did not have the appropriate knowledge in type 2 diabetes, as well as health literacy which was also moderate. These results confirmed the need to develop of education for improving and increasing the appropriate knowledge and health literacy among studied women

Renal biochemical and histopathological alterations of diabetic rats under treatment with hydro alcoholic Morus nigra extrac.

Introduction: Morus nigra fruit is known to have antioxidant effects and used to control the blood sugar level in traditional medicine. Objectives: This study was conducted to investigate the biochemical and histopathological changes in the serum and kidneys of diabetic rats treated with hydroalcoholic M. nigra extract. Materials and Methods: In this study, 60 male Wistar rats were divided into five groups of 12 each. After induction of diabetes with alloxan, the diabetic rats were treated with hydroalcoholic extract of M. nigra at different concentrations. Then, the animals were anesthetized and the serum levels of glucose, creatinine, and urea as well as kidney tissue catalase level measured. The kidney tissue was also histopathologically examined. Results: Milder glomerular damage was seen in the group treated with 800 mg/kg of the M. nigra extract compared with diabetic and positive controls, and no difference in the expansion of mesenchymal tissue into renal glomerular vessels observed between the group treated with 800 mg/kg of M. nigra extract and diabetic and positive controls. Furthermore, creatinine levels were significantly higher and urea levels significantly lower in the group treated with 800 mg/kg of M. nigra extract than healthy and positive control groups (P<0.05). Conclusion: Administration of M. nigra extract at 800 mg/kg can prevent kidney tissue damage in diabetic rats and this fruit seems to be beneficial to patients with diabetes

Biochemical and histopathological changes in kidney of diabetic rats treated with hydroalcoholic extract of Centaurea cyanus

Background and purpose: Diabetes mellitus is a common metabolic disease, currently affecting more than 280 million people worldwide. Centaurea cyanus known as cornflower has antioxidant properties and is used in traditional medicine in lowering blood sugar. This study aimed at determining the biochemical and histopathological changes in serum and the kidneys of diabetic rats treated with hydroalcoholic extract of Centaurea cyanus. Materials and methods: In this study, 60 male Wistar rats were divided into five groups (n= 12 per group). Diabetes was induced by alloxan. The diabetic rats were treated for 8 weeks with hydro alcoholic extract of C. cyanus at two concentrations (400 and 800 mg/kg). Finally, the animals were anesthetized and the serum levels of glucose, creatinine and urea and kidney tissue catalase level were measured. The kidney tissue slides were histopathologically examined. Results: Histopathological examination showed that similar to the control group, there were no significant changes in histolological features of the group receiving 800 mg/kg extract of the C. cyanus. In the group treated with 400 mg/kg of the extract there were mild tubular changes. Biochemical examination showed higher levels of creatinine in the group receiving the extract at 800 mg/kg. The level of urea in the group receiving the extract at 400 mg/kg, was significantly higher compared to that of the control group. (P<0.05). Conclusion: Consumption of Centaurea cyanus extract at 800 mg/kg could prevent kidney tissue injuries in diabetic rats, but further investigations are required before its use in treatment of patients with diabetes. © 2016, Mazandaran University of Medical Sciences. Engineering. All rights reserved

The prevalence of antithyroid antibodies in women with polycystic ovary syndrome in Shahrekord, Iran

زمینه و هدف: سندروم تخمدان پلی کیستیک با چاقی و مقاومت به انسولین همراه است. یافته ها و شواهد نشان می دهد بافت چربی نقشی مهم در ایجاد و پایداری اختلالات موجود در سندروم تخمدان پلی کیستیک دارد. تیرویید نقش بسیار برجسته و چشمگیری در سوخت و ساز بدن به ویژه متابولیسم لیپیدها و کربوهیدرات‌ها دارد. سندروم تخمدان پلی کیستیک و بیماری های تیروئید با اختلال در کارکرد محور، هیپوتالاموس-هیپوفیز گناد همراهند. این پژوهش با هدف بررسی ارتباط آنتی بادی های ضد تیرویید و ابتلا به سندرم تخمدان پلی کیستیک انجام شد. روش بررسی: در این مطالعه توصیفی-تحلیلی دو گروه 54 نفره از زنان 15 تا 45 ساله مراجعه کننده به درمانگاه های وابسته به دانشگاه علوم پزشکی شهرکرد به روش در دسترس انتخاب شد. و به صورت پی در پی وارد مطالعه شدند. گروه اول (شاهد) افرادی بودند که بر پایه شرح حال، معاینه بالینی و آزمایش های انجام شده هیچ گونه بیماری تیرویید، اختلالات سیستمیک و سندروم تخمدان پلی‌کیستیک نداشتند و هیچ گونه دارویـــی مصرف نمی کردند. گروه دوم (بیماران) بیمارانی بودند که بر پایه شرح حال، معاینه بالینی و آزمایش های انجام شده هیچ گونه بیماری تیرویید و اختلالات سیستمیک نداشتند ولی دچار سندروم تخمدان پلی کیستیک بودند. آنتی بادی های ضد تیرویید در هر دو گروه اندازه گیری و داده ها به کمک آزمون های آماری کای دو، t و آنالیز واریانس تجزیه و تحلیل شد. یافته ها: بین بیماران و گروه کنترل تفاوت معنی داری از نظر شیوع ومقدار آنتی بادی های ضد تیرویید وجود نداشت (05/0P>). میزان تری یدوتیروئید (T3) و تیروکسین (T4) در گروه سندروم تخمدان پلی کیستیک، به طور معنی داری بالاتر از گروه شاهد بود (05/0

Traffic Police Effectiveness and Efficiency Evaluations, an Overview of Methodological Considerations

Context: Every government implements various policies to mitigate road traffic injuries (RTIs). Many of these interventions are performed by traffic police. To evaluate effectiveness and efficiency of police enforcement, numerous studies have been conducted. Potential capabilities of epidemiology could get opportunity to improve these studies. The aim of this study was to extract and discuss some related methodological points of traffic police effectiveness and efficiency from related studies, in view of epidemiology discipline. Evidence Acquisition: Related articles were searched with “traffic police”, “effectiveness”, “efficiency” and “road safety” keywords in ScienceDirect, PubMed and Safetylit databases. Related papers were selected and read carefully to summarize and discuss the epidemiological points with aims of giving clues to improve quality of studies. Results: From a total of 797 articles, 20 were eligible which among them 17 articles were about effectiveness and 3 of them were about efficiency evaluations. Discussed points were the method of study, taking a holistic view to all positive and negative side effects, desired inputs and outputs, relation pattern between police enforcement and outcome and potential confounders. Conclusions: Better understanding of the effectiveness and efficiency mechanism and having valid evaluation required considering specific theories and points in this field. Applying a dynamic approach with considering epidemiological concepts and sophisticated statistical models could improve quality of studies in this field

A study on the relationship between Tabriz high school teachers’ sense of efficacy and their educational quality

For many years, one of the main aims of pedagogy is the promotion of educational quality. Any impressive achievement in educational quality and pedagogy needs to be active participation and support by teachers. Considering the important role of the teacher in promotion of educational quality, this study was to investigate the relationship between Tabriz high school teachers’ senses of efficacy and their educational quality to shed some lights on the blurred issues in this regard. To this end 60 high school teachers (30 psychology teachers and 30 physics teachers) were selected from the population of study. For assessing educational quality, Flanders Interaction Analysis Category, and for evaluating teachers' sense of efficacy, Ohio Teacher Sense of Efficacy Scale was used. The results of Canonical correlation indicated that only one root of analysis was significant and from the predictor variables, teacher sense of efficacy is significantly related to the indirect to direct teaching method and teacher- student reactions