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We apply innovative mathematical tools coming from optimal control theory to improve theoretical and experimental techniques in Magnetic Resonance Imaging (MRI). This approach allows us to explore and to experimentally reach the physical…

Quantum Physics · Physics 2017-09-11 E. Van-Reeth , H. Ratiney , M. Lapert , S. J. Glaser , D. Sugny

The objective of this article is to introduce the tools to analyze the contrast imaging problem in Nuclear Magnetic Resonance. Optimal trajectories can be selected among extremal solutions of the Pontryagin Maximum Principle applied to this…

Quantum Physics · Physics 2016-11-15 B. Bonnard , O. Cots , S. J. Glaser , M. Lapert , D. Sugny , Y. Zhang

Magnetic Resonance Imaging (MRI) can be considered one of the most effective techniques in both clinical diagnostic medical field and biomedicine, as it allows to obtain images anatomy of the body and its various parts and information…

Fluid Dynamics · Physics 2011-02-02 Stefania Nicolosi

We derive upper bounds to free-space concentration of electromagnetic waves, mapping out the limits to maximum intensity for any spot size and optical beam-shaping device. For sub-diffraction-limited optical beams, our bounds suggest the…

Optics · Physics 2020-07-08 Hyungki Shim , Haejun Chung , Owen D. Miller

Characterization of microstructures in live tissues is one of the keys to diagnosing early stages of pathology and understanding disease mechanisms. However, the extraction of reliable information on biomarkers based on microstructure…

Quantum Physics · Physics 2020-09-01 Analia Zwick , Dieter Suter , Gershon Kurizki , Gonzalo A. Alvarez

Magnetic resonance (MR) images from multiple sources often show differences in image contrast related to acquisition settings or the used scanner type. For long-term studies, longitudinal comparability is essential but can be impaired by…

Image and Video Processing · Electrical Eng. & Systems 2023-03-16 Alicia Durrer , Julia Wolleb , Florentin Bieder , Tim Sinnecker , Matthias Weigel , Robin Sandkühler , Cristina Granziera , Özgür Yaldizli , Philippe C. Cattin

Magnetic Detection Electrical Impedance Tomography is a novel technique that could enable non-invasive imaging of fast neural activity in the brain. However, commercial magnetometers are not suited to its technical requirements.…

Medical Physics · Physics 2024-12-19 Kai Mason , Florencia Maurino-Alperovich , Kirill Aristovich , David Holder

Photonic devices play an increasingly important role in advancing physics and engineering, and while improvements in nanofabrication and computational methods have driven dramatic progress in expanding the range of achievable optical…

Physical design problems, such as photonic inverse design, are typically solved using local optimization methods. These methods often produce what appear to be good or very good designs when compared to classical design methods, but it is…

Optics · Physics 2020-05-20 Guillermo Angeris , Jelena Vuckovic , Stephen Boyd

Response functions of resonant circuits create ringing artefacts if their input changes rapidly. When physical limits of electromagnetic spectroscopies are explored, this creates two types of problems. Firstly, simulation: the system must…

Systems and Control · Electrical Eng. & Systems 2023-07-19 Uluk Rasulov , Anupama Acharya , Marina Carravetta , Guinevere Mathies , Ilya Kuprov

Control theory has recently been involved in the field of nuclear magnetic resonance imagery. The goal is to control the magnetic field optimally in order to improve the contrast between two biological matters on the pictures. Geometric…

Symbolic Computation · Computer Science 2017-07-07 Bernard Bonnard , Jean-Charles Faugère , Alain Jacquemard , Mohab Safey El Din , Thibaut Verron

Magnetic Resonance Imaging (MRI) has become one of the most important tools to screen humans in medicine, virtually every modern hospital is equipped with an NMR tomograph. The potential of NMR in 3D imaging tasks is by far greater, but…

Soft Condensed Matter · Physics 2018-09-14 Ralf Stannarius

Compressed sensing takes advantage of low-dimensional signal structure to reduce sampling requirements far below the Nyquist rate. In magnetic resonance imaging (MRI), this often takes the form of sparsity through wavelet transform, finite…

Image and Video Processing · Electrical Eng. & Systems 2020-02-19 Jonathan I. Tamir , Frank Ong , Suma Anand , Ekin Karasan , Ke Wang , Michael Lustig

Magnetic resonance imaging (MRI) is a widely used biomedical imaging modality that derives much of its contrast from microscale magnetic field gradients in biological tissues. However, the connection between these sub-voxel field patterns…

Purpose: Spectral imaging is a method in medical x-ray imaging to extract information about the object constituents by the material-specific energy dependence of x-ray attenuation. The authors have investigated a photon-counting spectral…

Medical Physics · Physics 2021-01-21 Erik Fredenberg , Magnus Hemmendorff , Bjorn Cederstrom , Magnus Aslund , Mats Danielsson

Previous studies have used numerical methods to optimize the hyperpolarizability of a one-dimensional quantum system. These studies were used to suggest properties of one-dimensional organic molecules, such as the degree of modulation of…

Optics · Physics 2015-05-18 Urszula B. Szafruga , Mark G. Kuzyk , David S. Watkins

The past decade has demonstrated increasing interests in using optimal control based methods within coherent quantum controllable systems. The versatility of such methods has been demonstrated with particular elegance within nuclear…

Quantum Physics · Physics 2015-05-18 Ivan I. Maximov , Niels Chr. Nielsen , Julien Salomon , Gabriel Turinici

Intensive light pulse interaction with a dense resonant medium is considered. The possibilities of optical switching and pulse compression at realistic parameters of the medium are analyzed. Pulse shape transformation in different photonic…

Optics · Physics 2009-08-27 Denis Novitsky

The spatial resolution of magnetic resonance imaging (MRI) is fundamentally limited by the width of Lorentzian point spread functions (PSF) associated with the exponential decay rate of transverse magnetization (1/T2*). Here we show a…

In the recent years, we witness a great interest in imaging, in a wide sense, using contrast agents. One of the reasons is that many imaging modalities, as the ones related to medical sciences, suffer from several shortcomings. The most…

Optics · Physics 2020-08-28 Ahcene Ghandriche , Mourad Sini
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