Applications In Cardiology Research Articles

Utilização da cintigrafia com iodo-123-metaiodobenzilguanidina na estratificação do risco de morte súbita na insuficiência cardíaca

Metaiodobenzylguanidine (MIBG) is a false neurotransmitter noradrenaline analogue that is taken up by the ‘uptake 1’ transporter mechanism in the cell membrane of presynaptic adrenergic neurons and accumulates in catecholamine storage vesicles. Since it is practically unmetabolized, it can be labeled with a radioisotope (iodine-123) in scintigraphic exams to noninvasively assess the functional status of the sympathetic innervation of organs with a significant adrenergic component, including the heart. Studies of its application in nuclear cardiology appear to confirm its value in the assessment of conditions such as coronary artery disease, heart failure, arrhythmias and sudden death.Heart failure is a global problem, with an estimated prevalence of 2% in developed countries. Sudden cardiac death is the main cause of its high mortality. The autonomic nervous system dysfunction, including sympathetic hyperactivity, that accompanies chronic heart failure is associated with progressive myocardial remodeling, declining left ventricular function and worsening symptoms, and contributes to the development of ventricular arrhythmias and sudden death.Since 123I-MIBG cardiac scintigraphy can detect changes in the cardiac adrenergic system, there is considerable interest in its role in obtaining diagnostic and prognostic information in patients with heart failure.In this article we present a literature review on the use of 123I-MIBG scintigraphy for risk stratification of sudden death in patients with heart failure.

Book Review: The Handbook of Nanomedicine (2Nd Edition)

The Handbook of Nanomedicine is an informative account of the current state of nanomedicine, combining descriptions of emerging technologies with examples of their utility. Now in its second edition, Kewal K Jain has thoroughly updated its content to reflect novel advances in the field. As this book was written by a lone author, it maintains a singular focus throughout, a highly advantageous facet not typically seen in similar publications. Topics range from an introduction to nanotechnologies to applications in specific fields, including oncology, cardiology and neurology. Overall, The Handbook of Nanomedicine (2nd Edition) was designed in such a manner that it could be easily read by anyone interested in the subject, with specific references selected to provide further, more detailed insight into specific topics.

Selecting Relevant Information for Medical Decision Support with Application in Cardiology

Objectives: The aim of our work was to implement a prototype of a decision support system which has the form of a web-based classification service. Because the data analysis component of decision support systems often happens to be unsuitable for high-dimensional data, special attention must be paid to the sophisticated selection of the most relevant variables before learning the classification rule. Methods: We implemented a prototype of a diagnostic decision support system called SIR. The system has the ability to select the most relevant variables based on a set of high-dimensional measurements by means of a forward procedure optimizing a decision-making criterion. This allows to learn a reliable classification rule. Results: The implemented prototype was tested on a sample of patients involved in a cardiology study. We used SIR to perform an information extraction from a cardiological clinical study containing both clinical and gene expression data. The classification performance was evaluated by means of a cross validation study. Conclusions: The proposed classification system can be useful for clinicians in primary care to support their decision-making tasks with relevant information extracted from any available clinical study. It is especially suitable for analyzing high-dimensional data, e.g. gene expression measurements.

Saturation‐recovery metabolic‐exchange rate imaging with hyperpolarized [1‐13C] pyruvate using spectral‐spatial excitation

Within the last decade hyperpolarized [1-13C] pyruvate chemical-shift imaging has demonstrated impressive potential for metabolic MR imaging for a wide range of applications in oncology, cardiology, and neurology. In this work, a highly efficient pulse sequence is described for time-resolved, multislice chemical shift imaging of the injected substrate and obtained downstream metabolites. Using spectral-spatial excitation in combination with single-shot spiral data acquisition, the overall encoding is evenly distributed between excitation and signal reception, allowing the encoding of one full two-dimensional metabolite image per excitation. The signal-to-noise ratio can be flexibly adjusted and optimized using lower flip angles for the pyruvate substrate and larger ones for the downstream metabolites. Selectively adjusting the excitation of the down-stream metabolites to 90° leads to a so-called "saturation-recovery" scheme with the detected signal content being determined by forward conversion of the available pyruvate. In case of repetitive excitations, the polarization is preserved using smaller flip angles for pyruvate. Metabolic exchange rates are determined spatially resolved from the metabolite images using a simplified two-site exchange model. This novel contrast is an important step toward more quantitative metabolic imaging. Goal of this work was to derive, analyze, and implement this "saturation-recovery metabolic exchange rate imaging" and demonstrate its capabilities in four rats bearing subcutaneous tumors.

Multigate Quality Doppler Profiles Technology in Vascular, Obstetrics and Cardiology Applications

Article Multigate Quality Doppler Profiles Technology in Vascular, Obstetrics and Cardiology Applications was published on August 24, 2012 in the journal Biomedical Engineering / Biomedizinische Technik (volume 57, issue SI-1-Track-B).

Description Logics as information resource: as example of its application in cardiology

This paper regards the study of terminologies, Ontology, and its inference in Description Logics. With no intent of broadening its comprehension, we depict description logics and its role as a mediator in Information and Computer Sciences and pointing at some of the most important resources that have currently caught the medical field’s attention. Based on previous writings, the main causes of death nowadays in developed and developing countries are related to cardiovascular diseases. Data from the World Health Organization (WHO) state that about 140,000 people die every year in Brazil due to heart disease. In addition, most of these deaths, including those caused by sudden illness, could be avoided by the premonitoring and the pre-diagnosis of cardiac arrhythmias and myocardial ischemia using ECG, since the electrocardiogram is one of the tools that offer fast and reliable data sets for cardiac diagnosis. This study has as a tool the analysis for the treatment and organization of digital information for its recovery, use, and reuse in a monitoring and automatic pre-diagnosis system to assist the doctor in quickly and accurately detecting cardiac arrhythmias. Therefore, the idea, in the methodological light of Information Sciences - creating, processing, preserving, and (re) using digital information - is to develop a system to generate, store, transfer, and interpret electrocardiogram information for cardiac arrhythmia diagnosis. The system should be used in health centers, mobile ICUs, hospitals and universities to assist health professionals when working on medical reports of patients with pathological abnormalities. As a result, it is expected that a system containing database of electrocardiograms, with pathologies related to clinical cases of cardiac diseases, will be introduced and approved as an assisting tool for health professionals to use throughout the process of managing information. They will prepare their patient’s clinical report to pass on information, following the principle of ubiquity, which when deployed in public health systems will provide faster assistance and accuracy in the identification of cardiac abnormalities, and patients will have specialized service. Thus, we introduce a structure of description logics and its approach in the cardiology medical environment, and we compare the use of description logics in the pathology environment by using a practical model of description logics use in terms of diseases related to the circulatory system of the human body.

New anticoagulants: pharmacology and clinical studies

The marketing of new anticoagulant drugs has led us to review the development of rivaroxaban and apixaban (oral anti-Xa drugs) and dabigatran (an oral thrombin inhibitor). The results are different in terms of efficacy and tolerance. Each molecule has its own field of application but it is not at all certain that each will find its place. Though the results are favourable for these orally active drugs in the orthopaedic setting, it is clear that only cardiological applications will give a final green light for these products. The future will be fascinating in this regard.

Optical coherence elastography: current status and future applications

Optical coherence tomography (OCT) has several advantages over other imaging modalities, such as angiography and ultrasound, due to its inherently high in vivo resolution, which allows for the identification of morphological tissue structures. Optical coherence elastography (OCE) benefits from the superior spatial resolution of OCT and has promising applications, including cancer diagnosis and the detailed characterization of arterial wall biomechanics, both of which are based on the elastic properties of the tissue under investigation. We present OCE principles based on techniques associated with static and dynamic tissue excitation, and their corresponding elastogram image-reconstruction algorithms are reviewed. OCE techniques, including the development of intravascular- or catheter-based OCE, are in their early stages of development but show great promise for surgical oncology or intravascular cardiology applications.

Assessment of myocardial ischaemia and viability: role of positron emission tomography

In developed countries, coronary artery disease (CAD) continues to be a major cause of death and disability. Over the past two decades, positron emission tomography (PET) imaging has become more widely accessible for the management of ischemic heart disease. Positron emission tomography has also emerged as an important alternative perfusion imaging modality in the context of recent shortages of molybdenum-99/technetium-99m ((99m)Tc). The clinical application of PET in ischaemic heart disease falls into two main categories: first, it is a well-established modality for evaluation of myocardial blood flow (MBF); second, it enables assessment of myocardial metabolism and viability in patients with ischaemic left ventricular dysfunction. The combined study of MBF and metabolism by PET has led to a better understanding of the pathophysiology of ischaemic heart disease. While there are potential future applications of PET for plaque and molecular imaging, as well as some clinical use in inflammatory conditions, this article provides an overview of the physical and biological principles behind PET imaging and its main clinical applications in cardiology, namely the assessment of MBF and metabolism.

Everolimus: A Proliferation Signal Inhibitor with Clinical Applications in Organ Transplantation, Oncology, and Cardiology

Everolimus, a proliferation signal inhibitor in the mammalian target of rapamycin (mTOR) drug class, has many clinical applications, including in organ transplantation, oncology, and cardiology. It currently has United States Food and Drug Administration (FDA) approval for prophylaxis against rejection in de novo renal transplant recipients, treatment of renal cell carcinoma, and use as a drug-eluting stent. To review the pharmacology, pharmacokinetics, efficacy, and safety of everolimus, we performed a search of the MEDLINE database (January 1997-April 2010) for all English-language articles of in vitro and in vivo studies that evaluated everolimus, as well as abstracts from recent scientific meetings and the manufacturer. In transplantation, everolimus demonstrates immunosuppressive properties and has been used to prevent acute rejection in cardiac, liver, lung, and renal transplant recipients. It appears that this agent may be potent enough to allow for the minimization or removal of calcineurin inhibitors in the long-term management of renal transplant recipients. In oncology, everolimus has been proven effective for the management of treatment-resistant renal cell carcinoma. In cardiology, everolimus is available as a drug-coated stent and is used in percutaneous coronary interventions for prevention of restenosis. In transplant recipients and patients with renal cell carcinoma, everolimus appears to have an extensive adverse-event profile. The pharmacologic properties of everolimus differentiate this agent from other drugs used in these clinical areas, and its pharmacokinetic properties differentiate it from sirolimus.

Frustrated drift of an anchored scroll-wave filament and the geodesic principle

We investigate anchored scroll-wave filaments in an excitable medium whose diffusivity matrix, including its determinant, is spatially nonuniform. The study is motivated by cardiological applications where scroll-wave behavior in the presence of diffusivity gradients is believed to play an important role in the development of severe arrhythmias. A diffusivity gradient is expected to make the filament drift, unless drift is prevented ("frustrated") by anchoring to localized defects in the propagation medium. The resulting stationary filament is a geodesic curve, as demonstrated here in the case of a nonzero but constant gradient. That is, the diffusivity matrix has a determinant that varies in space, in contrast to what was assumed in earlier work. Here, we show that the filament shape results from a metric tensor of the form (det D)D{-1} , where D is the diffusivity tensor. The filament's shape is solely determined by the diffusivity tensor and is independent of the equation's reaction terms. We derive the analytic solution for the filament and determine conditions for the existence of that solution. The theory is in excellent agreement with numerical simulations.

Combined PET/MR Imaging — Technology and Applications

The combination of PET and MR in one imaging device has certain advantages over conventional imaging modalities. These include: no additional radiation dose from the MR, superior soft tissue contrast and a multitude of tracers for PET. Certain technical challenges exist when designing a PET/MR system. On the one hand these stem from the presence of the strong MR magnetic field and the addition of PET components to the MR system. Different approaches are presented to overcome these technical obstacles ranging from long optical fibers to systems that use semiconductor light detectors for photon counting. The applications of combined PET/MR are profound in the field of oncology and allow imaging of the four main processes in cancer formation: apoptosis resistance, angiogenesis, proliferation and metastasis. PET/MR has also many clinical and research applications in neurology and cardiology. Alternative techniques such as image fusion, hyperpolarized imaging, 17O imaging and whole body diffusion are discussed in respect to their relevance regarding PET/MR. Simultaneous multifunctional and anatomical imaging using PET/MR has a great potential to impact biomedical imaging in research and clinic.

Optical coherence tomography – development, principles, applications

This paper presents a review of the development of optical coherence tomography (OCT), its principles and important applications. Basic OCT systems are described and the physical foundations of OCT signal properties and signal recording systems are reviewed. Recent examples of OCT applications in ophthalmology, cardiology, gastroenterology and dermatology outline the relevance of this advanced imaging modality in the medical field.

Clinical applications of PET and PET-CT

Positron emission tomography (PET) and PET/ computed tomography (CT) are emerging as important imaging techniques and their popularity is growing within the medical fraternity. Though PET has been a useful research tool for many decades its real growth into clinical applications has occurred in the last one decade or so. Currently its major use is in oncologic imaging. However it has a multitude of clinical applications in cardiology, neurology and psychiatry as well. In oncologic imaging, a major advantage of PET is that a single whole-body examination can provide accurate assessment of disease activity and spread. PET/CT amalgamates the functional information of PET with the structural details of the CT scan, thus greatly aiding in accurate staging, therapy response assessment and early detection of recurrent disease.

The Advent of Laser Therapies in Dermatology and Urology: Underlying Mechanisms, Recent Trends and Future Directions

Following their applications in cardiology, ophthalmology and dentistry among others, the advent of lasers in dermatology and urology had become the success story of the past decade. Laser-assisted treatments in dermatology and urology are mainly based on the laser-induced tissue injury/coagulation and/or ablation, depending upon the desirable clinical endpoint. In this review, we discussed the underlying mechanisms of the laser induced tissue ablation. In any medical laser application, the controlled thermal injury and coagulation, and the extent of ablation, if required, are critical. The laser thermal mechanism of injury is intricately related to the selective absorption of light and its exposure duration, similarly to the laser induced ablation. The laser ablation mechanisms were categorized into four different categories (the photo-thermally induced ablation, the photo-mechanically induced ablation, the plasma induced ablation and the photoablation) and their fundamentals are herein described. The brief history of laser treatment modality in dermatology and urology are summarized.

COTS technologies for telemedicine applications

To demonstrate a simple low-cost system for tele-echocardiology, focused on paediatric cardiology applications. The system was realized using open-source software and COTS technologies. It is based on the transmission of two simultaneous video streams, obtained by direct digitization of the output of an ultrasound machine and by a netcam showing the examination that is taking place. These streams are then embedded into a web page so they are accessible, together with basic video controls, via a standard web browser. The system can also record video streams on a server for further use. The system was tested on a small group of neonatal cases with suspected cardiopathies for a preliminary assessment of its features and diagnostic capabilities. Both the clinical and technological results were encouraging and are leading the way for further experimentation. The presented system can transfer clinical images and videos in an efficient way and in real time. It can be used in the same hospital to support internal consultancy requests, in remote areas using Internet connections and for didactic purposes using low cost COTS appliances and simple interfaces for end users. The solution proposed can be extended to control different medical appliances in those remote hospitals.

A Novel High-Sensitivity Rapid-Acquisition Single-Photon Cardiac Imaging Camera

This study described and validated a new solid-state single-photon gamma-camera and compared it with a conventional-SPECT Anger camera. The compact new camera uses a unique method for localizing gamma-photon information with a bank of 9 solid-state detector columns with tungsten collimators that rotate independently. Several phantom studies were performed comparing the new technology with conventional-SPECT technology. These included measurements of line sources and single- and dual-radionuclide studies of a torso phantom. Simulations were also performed using a cardiothoracic phantom. Furthermore, 18 patients were scanned with both the new camera and a conventional-SPECT camera. The new camera had a count sensitivity that was 10 times higher than that of the conventional camera and a compensated spatial resolution that was moderately better. Dual-radionuclide studies using a phantom show the further potential of the new camera for a 2-tracer simultaneous acquisition. Two-minute clinical studies with the new camera and 11-min studies with the conventional camera qualitatively showed good-to-excellent image quality and improved myocardial edge definition for the new camera. These initial performance characteristics of a new solid-state single-photon gamma-camera offer great promise for clinical dynamic SPECT protocols, with important implications for applications in nuclear cardiology and molecular imaging.

Multimodality image registration with software: state-of-the-art

Multimodality image integration of functional and anatomical data can be performed by means of dedicated hybrid imaging systems or by software image co-registration techniques. Hybrid positron emission tomography (PET)/computed tomography (CT) systems have found wide acceptance in oncological imaging, while software registration techniques have a significant role in patient-specific, cost-effective, and radiation dose-effective application of integrated imaging. Software techniques allow accurate (2-3 mm) rigid image registration of brain PET with CT and MRI. Nonlinear techniques are used in whole-body image registration, and recent developments allow for significantly accelerated computing times. Nonlinear software registration of PET with CT or MRI is required for multimodality radiation planning. Difficulties remain in the validation of nonlinear registration of soft tissue organs. The utilization of software-based multimodality image integration in a clinical environment is sometimes hindered by the lack of appropriate picture archiving and communication systems (PACS) infrastructure needed to efficiently and automatically integrate all available images into one common database. In cardiology applications, multimodality PET/single photon emission computed tomography and coronary CT angiography imaging is typically not required unless the results of one of the tests are equivocal. Software image registration is likely to be used in a complementary fashion with hybrid PET/CT or PET/magnetic resonance imaging systems. Software registration of stand-alone scans "paved the way" for the clinical application of hybrid scanners, demonstrating practical benefits of image integration before the hybrid dual-modality devices were available.

Factors Affecting Relevance of Tele-ECG Systems Application to High Risk for Future Ischemic Heart Disease Events Patients Group

Telecardiology can identify patients with urgent problems requiring rapid assessment at the hospital or even emergency admission. Telemedicine applications in cardiology must identify factors that make the service most beneficial to the patients. The aim of the study was to analyze factors affecting relevance and benefits of telephonic electrocardiography (ECG) consultations. A transnational telephonic ECG system was established between Lithuania and Germany. Using a follow-up study design, clinical performance and beneficial factors for telecardiology were assessed. According to inclusion and exclusion criteria, 34 patients sent 329 ECGs with 14 ECG showing important clinical changes. Of the 329 ECGs only 263 (80%) ECGs were of acceptable quality for clinical interpretation. Most important factors associated with benefits from tele-ECG service were gender, Thrombolysis in Myocardial Infarction (TIMI), Systematic Coronary Risk Evaluation (SCORE) risk stratification, and chest pain in previous month. Tele-ECG service of routine ECGs can be useful in recognition of silent ischemia or arrhythmias, and facilitating diagnosis. However, other factors such as chest pain in the previous month, gender, TIMI, and SCORE risk stratifications are important in planning tele-ECG services.

Clinical use of FDG PET

2-[18F]-Fluoro-2-deoxy-D-glucose (FDG) has a wide range of possible clinical imaging applications in neurology, oncology and cardiology; however, there is also a large difference in the volume of actual clinical use between these applications. Three clinical questions are proposed and applied to the various clinical applications of FDG to understand this difference: (a) Are there competing tests? (b) Is there a cost-effective role in the clinical management? (c) Is the interpretation of the imaging study easy? Each clinical application using FDG was reviewed with the three clinical questions proposed and the technical factor that may have contributed to addressing that question. The review of the application was based on the current practice of neurology, oncology and cardiology, and the contributing factors were based on the properties of FDG and the capabilities of the technology of current positron emission tomography scanners. A favorable answer was obtained for all three questions in oncology imaging with FDG. In cardiology and neurology, one of the three questions had an unfavorable outcome. Three clinical questions are proposed and applied to clinical FDG imaging in neurology, cardiology and oncology with the intent of better understanding the variation of clinical use.