Download or read book Quantitative MR Imaging of the Electric Properties and Local SAR Based on Improved RF Transmit Field Mapping written by Tobias Voigt and published by KIT Scientific Publishing. This book was released on 2014-08-18 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents three new quantitative methods for magnetic resonance imaging. A method for simultaneous mapping of B1 and T1 (MTM) is developed and validated. Electric Properties Tomography (EPT), a method for quantitative imaging of dielectric properties of tissue, is presented. Based on EPT, separate (phase-based) conductivity and (amplitude-based) permittivity measurements are introduced. Finally, a B1-based method for patient-specific local SAR measurements is presented.
Download or read book Molecular Plasmonics written by Volodymyr I. Chegel and published by Jenny Stanford Publishing. This book was released on 2020-11-18 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarizes the results of studies of molecules and molecular complexes using techniques based on surface plasmon resonance (SPR) in a novel scientific direction called molecular plasmonics. It presents the current state of investigations in the field of molecular plasmonics and discusses its two main physical phenomena: surface plasmon–polariton resonance (SPPR) and localized SPR (LSPR). Among the mathematical methods for the calculation of plasmonic systems response, the book emphasizes models based on the transfer-matrix method, Green function formalism, Mie scattering theory, and numerical methods. It considers the possibilities of the SPPR technique for registering conformational changes, surface plasmon–mediated photopolymerization, electrochemical processes, as well as reversible optoelectronic and physicochemical properties during investigation of molecular systems. It describes applications of the LSPR method, including creation of metamaterials, surface-enhanced fluorescence, and bio- and chemosensing using noble metal nanoparticles in colloidal, array, and composite polymeric film formats. It also highlights the development and applications of plasmonic nanochips.
Download or read book Quantifying Morphology and Physiology of the Human Body Using MRI written by L. Tugan Muftuler and published by Taylor & Francis. This book was released on 2013-05-02 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the medical imaging field, clinicians and researchers are increasingly moving from the qualitative assessment of printed images to the quantitative evaluation of digital images since the quantitative techniques often improve diagnostic accuracy and complement clinical assessments by providing objective criteria. Despite this growing interest, th
Download or read book SAR Prediction and SAR Management for Parallel Transmit MRI written by Hanno Homann and published by KIT Scientific Publishing. This book was released on 2014-07-30 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Parallel transmission enables control of the RF field in high-field Magnetic Resonance Imaging (MRI). However, the approach has also caused concerns about the specific absorption rate (SAR) in the patient body. The present work provides new concepts for SAR prediction. A novel approach for generating human body models is proposed, based on a water-fat separated MRI pre-scan. Furthermore, this work explores various approaches for SAR reduction.
Download or read book ECG Imaging of Ventricular Activity in Clinical Applications written by Schulze, Walther H. W. and published by KIT Scientific Publishing. This book was released on 2015-08-12 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: ECG imaging was performed in humans to reconstruct ventricular activation patterns and localize their excitation origins. The precision of the non-invasive reconstructions was evaluated against invasive measurements and found to be in line with the state-of-the-art literature. Statistics were produced for various excitation origins and reveal the beat-to-beat robustness of the imaging method.
Download or read book ECG Based Analysis of the Ventricular Repolarisation in the Human Heart written by Baas, Tobias and published by KIT Scientific Publishing. This book was released on 2012-08-06 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: ECG recordings provide diagnostic relevant information on the de- and repolarisation sequences of the heart. A modification of the repolarisation sequence is assumed to cause Torsades de Pointes. Especially drug induced effects on the repolarisation processes are in focus, since some non-cardiac drugs have been associated with sudden cardiac death in the 1990s.The analysis of the ventricular repolarisation using a set of parameters depicting the morphology of the T-wave is introduced in this work. Therefore, new methods of fully automatic patient-specific QRS detection, beat classification and precise T-wave delineation are presented. Using these methods, medical studies are investigated regarding the modification of the T-wave by different compounds. Also the impact of the heart rate on the morphology of the T-wave is part of this research.The reliable identification of ventricular ectopic beats allows an analysis of the influence of these beats on subsequent heart beats. It turned out that the morphology of subsequent heart beats can significantly be changed. This might give new information on the proarrythmical risk of ventricular ectopic beats.
Download or read book Modeling Human Atrial Patho Electrophysiology from Ion Channels to ECG Substrates Pharmacology Vulnerability and P Waves written by Loewe, Axel and published by KIT Scientific Publishing. This book was released on 2016-08-03 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: Half of the patients suffering from atrial fibrillation (AF) cannot be treated adequately, today. This book presents multi-scale computational methods to advance our understanding of patho-mechanisms, to improve the diagnosis of patients harboring an arrhythmogenic substrate, and to tailor therapy. The modeling pipeline ranges from ion channels on the subcellular level up to the ECG on the body surface. The tailored therapeutic approaches carry the potential to reduce the burden of AF.
Download or read book Personalized Multi Scale Modeling of the Atria Heterogeneities Fiber Architecture Hemodialysis and Ablation Therapy written by Martin Wolfgang Krüger and published by KIT Scientific Publishing. This book was released on 2014-05-22 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book targets three fields of computational multi-scale cardiac modeling. First, advanced models of the cellular atrial electrophysiology and fiber orientation are introduced. Second, novel methods to create patient-specific models of the atria are described. Third, applications of personalized models in basic research and clinical practice are presented. The results mark an important step towards the patient-specific model-based atrial fibrillation diagnosis, understanding and treatment.
Download or read book Multiscale Modeling of Cardiac Electrophysiology Adaptation to Atrial and Ventricular Rhythm Disorders and Pharmacological Treatment written by Mathias Wilhelms and published by KIT Scientific Publishing. This book was released on 2014-05-22 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiscale modeling of cardiac electrophysiology helps to better understand the underlying mechanisms of atrial fibrillation, acute cardiac ischemia and pharmacological treatment. For this purpose, measurement data reflecting these conditions have to be integrated into models of cardiac electrophysiology. Several methods for this model adaptation are introduced in this thesis. The resulting effects are investigated in multiscale simulations ranging from the ion channel up to the body surface.AbstractEnglisch = Multiscale modeling of cardiac electrophysiology helps to better understand the underlying mechanisms of atrial fibrillation, acute cardiac ischemia and pharmacological treatment. For this purpose, measurement data reflecting these conditions have to be integrated into models of cardiac electrophysiology. Several methods for this model adaptation are introduced in this thesis. The resulting effects are investigated in multiscale simulations ranging from the ion channel up to the body surface.
Download or read book Formation of Intracardiac Electrograms under Physiological and Pathological Conditions written by Keller, Matthias and published by KIT Scientific Publishing. This book was released on 2014-09-09 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents methods to advance electrophysiological simulations of intracardiac electrograms (IEGM). An experimental setup is introduced, which combines electrical measurements of extracellular potentials with a method for optical acquisition of the transmembrane voltage in-vitro. Thereby, intracardiac electrograms can be recorded under defined conditions. Using experimental and clinical signals, detailed simulations of IEGMs are parametrized, which can support clinical diagnosis.
Download or read book Effects of Time Varying Magnetic Fields in the Frequency Range 1 KHz to 100 KHz Upon the Human Body written by Julia Bohnert and published by KIT Scientific Publishing. This book was released on 2014-05-12 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, the physiological effects of time-varying magnetic fields up to 100 kHz have been investigated, namely magnetic stimulation and body warming. Simulation studies were based on numerical calculations on sophisticated cell and body models. In addition, magnetic stimulation thresholds have been determined experimentally.The project was carried out within the scope of the development of Magnetic Particle Imaging, a new imaging technology for medical diagnostics.
Download or read book Analysis of Atrial Electrograms written by Christopher Schilling and published by KIT Scientific Publishing. This book was released on 2012 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work provides methods to measure and analyze features of atrial electrograms - especially complex fractionated atrial electrograms (CFAEs) - mathematically. Automated classification of CFAEs into clinical meaningful classes is applied and the newly gained electrogram information is visualized on patient specific 3D models of the atria. Clinical applications of the presented methods showed that quantitative measures of CFAEs reveal beneficial information about the underlying arrhythmia.
Download or read book Characterizing Cardiac Electrophysiology during Radiofrequency Ablation An Integrative Ex vivo In silico and In vivo Approach written by Pollnow, Stefan and published by KIT Scientific Publishing. This book was released on 2019-04-23 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Multiscale In Silico Study to Characterize the Atrial Electrical Activity of Patients With Atrial Fibrillation A Translational Study to Guide Ablation Therapy written by Sánchez Arciniegas, Jorge Patricio and published by KIT Scientific Publishing. This book was released on 2022-05-30 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: The atrial substrate undergoes electrical and structural remodeling during atrial fibrillation. Detailed multiscale models were used to study the effect of structural remodeling induced at the cellular and tissue levels. Simulated electrograms were used to train a machine-learning algorithm to characterize the substrate. Also, wave propagation direction was tracked from unannotated electrograms. In conclusion, in silico experiments provide insight into electrograms' information of the substrate.
Download or read book Modified Mass spring System for Physically Based Deformation Modeling written by Oussama Jarrousse and published by KIT Scientific Publishing. This book was released on 2014-09 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mass-spring systems are considered the simplest and most intuitive of all deformable models. They are computationally efficient, and can handle large deformations with ease. But they suffer several intrinsic limitations. In this book a modified mass-spring system for physically based deformation modeling that addresses the limitations and solves them elegantly is presented. Several implementations in modeling breast mechanics, heart mechanics and for elastic images registration are presented.
Download or read book Multiscale Cohort Modeling of Atrial Electrophysiology Risk Stratification for Atrial Fibrillation through Machine Learning on Electrocardiograms written by Nagel, Claudia and published by KIT Scientific Publishing. This book was released on 2023-04-24 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: An early detection and diagnosis of atrial fibrillation sets the course for timely intervention to prevent potentially occurring comorbidities. Electrocardiogram data resulting from electrophysiological cohort modeling and simulation can be a valuable data resource for improving automated atrial fibrillation risk stratification with machine learning techniques and thus, reduces the risk of stroke in affected patients.
Download or read book Electrical Properties of Tissues written by Rosalind Sadleir and published by Springer Nature. This book was released on 2022-10-28 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the latest developments in tissue electrical conductivity and current density imaging, increasingly popular as well as challenging applications of MRI. These applications are enabled by the acquisition of high-quality MR phase images. This book provides a practical description of the MRI physics needed to understand and acquire phase images in MRI and the key details required to reconstruct them into conductivity, current density or electric field distributions. Comprehensive details are provided about the electrical properties of biological tissues, computational modeling considerations, experimental methods, construction of non-biological and biological phantoms and MRI pulse sequences. An inclusive review of image reconstruction algorithms, and their potential applications is provided for applications directed at determining current density or electric fields, such as in transcranial DC or AC stimulation techniques; as well as electrical conductivity reconstructions that may be of use in quantitative MRI applications used to detect cancer or other pathologies. This is an excellent book for undergraduate and graduate students beginning to explore phase, current density, and conductivity imaging in MRI, and will also be of great use to researchers interested in the area of MR-based electrical property imaging.