8,400 research outputs found
3D/2D Registration of Mapping Catheter Images for Arrhythmia Interventional Assistance
Radiofrequency (RF) catheter ablation has transformed treatment for
tachyarrhythmias and has become first-line therapy for some tachycardias. The
precise localization of the arrhythmogenic site and the positioning of the RF
catheter over that site are problematic: they can impair the efficiency of the
procedure and are time consuming (several hours). Electroanatomic mapping
technologies are available that enable the display of the cardiac chambers and
the relative position of ablation lesions. However, these are expensive and use
custom-made catheters. The proposed methodology makes use of standard catheters
and inexpensive technology in order to create a 3D volume of the heart chamber
affected by the arrhythmia. Further, we propose a novel method that uses a
priori 3D information of the mapping catheter in order to estimate the 3D
locations of multiple electrodes across single view C-arm images. The monoplane
algorithm is tested for feasibility on computer simulations and initial canine
data.Comment: International Journal of Computer Science Issues, IJCSI, Volume 4,
Issue 2, pp10-19, September 200
Resident research associateships. Postdoctoral and senior research awards: Opportunities for research at the Jet Propulsion Laboratory
Opportunities for research as part of NASA-sponsored programs at the JPL cover: Earth and space sciences; systems; telecommunications science and engineering; control and energy conversion; applied mechanics; information systems; and observational systems. General information on applying for an award for tenure as a guest investigator, conditions, of the award, and details of the application procedure are provided
Degenerate quantum gases of strontium
Degenerate quantum gases of alkaline-earth-like elements open new
opportunities in research areas ranging from molecular physics to the study of
strongly correlated systems. These experiments exploit the rich electronic
structure of these elements, which is markedly different from the one of other
species for which quantum degeneracy has been attained. Specifically,
alkaline-earth-like atoms, such as strontium, feature metastable triplet
states, narrow intercombination lines, and a non-magnetic, closed-shell ground
state. This review covers the creation of quantum degenerate gases of strontium
and the first experiments performed with this new system. It focuses on
laser-cooling and evaporation schemes, which enable the creation of
Bose-Einstein condensates and degenerate Fermi gases of all strontium isotopes,
and shows how they are used for the investigation of optical Feshbach
resonances, the study of degenerate gases loaded into an optical lattice, as
well as the coherent creation of Sr_2 molecules.Comment: Review paper, 43 pages, 24 figures, 249 reference
Imaging in forensic science: Five years on
The Journal of Forensic Radiology and Imaging was launched in 2013 with the aim to collate the literature and demonstrate high-quality case studies on image-based modalities across the forensic sciences. Largely, the focus of this journal has been on the transmissive aspect of forensic imaging, and therefore a significant number of high-quality case studies have been published focusing on computed tomography and magnetic resonance imaging. As a result, the ‘and imaging’ aspect is often neglected. Since 2013, technology has fundamentally evolved, and a number of new techniques have become accessible or have been demonstrated as particularly useful within many sub-disciplines of forensic science. These include active and passive surface scanning techniques, and the availability of three-dimensional printing. Therefore, this article discusses non-contact techniques, their applications, advantages, and considerations on the current state of play of imaging in forensic science
Precision Spectroscopy of Molecular Hydrogen Ions: Towards Frequency Metrology of Particle Masses
We describe the current status of high-precision ab initio calculations of
the spectra of molecular hydrogen ions (H_2^+ and HD^+) and of two experiments
for vibrational spectroscopy. The perspectives for a comparison between theory
and experiment at a level of 1 ppb are considered.Comment: 26 pages, 13 figures, 1 table, to appear in "Precision Physics of
Simple Atomic Systems", Lecture Notes in Physics, Springer, 200
A Review on Computer Aided Diagnosis of Acute Brain Stroke.
Amongst the most common causes of death globally, stroke is one of top three affecting over 100 million people worldwide annually. There are two classes of stroke, namely ischemic stroke (due to impairment of blood supply, accounting for ~70% of all strokes) and hemorrhagic stroke (due to bleeding), both of which can result, if untreated, in permanently damaged brain tissue. The discovery that the affected brain tissue (i.e., 'ischemic penumbra') can be salvaged from permanent damage and the bourgeoning growth in computer aided diagnosis has led to major advances in stroke management. Abiding to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines, we have surveyed a total of 177 research papers published between 2010 and 2021 to highlight the current status and challenges faced by computer aided diagnosis (CAD), machine learning (ML) and deep learning (DL) based techniques for CT and MRI as prime modalities for stroke detection and lesion region segmentation. This work concludes by showcasing the current requirement of this domain, the preferred modality, and prospective research areas
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Recent Trends in Imaging for Atrial Fibrillation Ablation
Catheter ablation provides an important treatment option for patients with both paroxysmal and persistent atrial fibrillation. It mainly involves pulmonary vein isolation and additional ablations in the left atrium in persistent cases. There have been significant advancements in this procedure to enhance the safety and effectiveness. One of them is the evolution of various imaging modalities to facilitate better visualization of the complex left atrial anatomy and the pulmonary veins in order to deliver the lesions accurately. In this article, we review the electroanatomic mapping systems including the magnetic-based and impedence-based systems. Each of these mapping systems has its own advantages and disadvantages. In addition, we also discuss the role of intracardiac echocardiography and three dimensional rotational angiography in atrial fibrillation ablation
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