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Parallel Magnetic Resonance Imaging [article]

Martin Uecker
<span title="2015-07-17">2015</span> <i > arXiv </i> &nbsp; <span class="release-stage" >pre-print</span>
The main disadvantage of Magnetic Resonance Imaging (MRI) are its long scan times and, in consequence, its sensitivity to motion. Exploiting the complementary information from multiple receive coils, parallel imaging is able to recover images from under-sampled k-space data and to accelerate the measurement. Because parallel magnetic resonance imaging can be used to accelerate basically any imaging sequence it has many important applications. Parallel imaging brought a fundamental shift in
more &raquo; ... reconstruction: Image reconstruction changed from a simple direct Fourier transform to the solution of an ill-conditioned inverse problem. This work gives an overview of image reconstruction from the perspective of inverse problems. After introducing basic concepts such as regularization, discretization, and iterative reconstruction, advanced topics are discussed including algorithms for auto-calibration, the connection to approximation theory, and the combination with compressed sensing.
<span class="external-identifiers"> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/1501.06209v2">arXiv:1501.06209v2</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/32f4xy4mc5afdmsh2z2wtkbafu">fatcat:32f4xy4mc5afdmsh2z2wtkbafu</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20200822233613/https://arxiv.org/pdf/1501.06209v2.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/50/fb/50fb652cfc2a4b62faa4323729704a736d87ba31.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/1501.06209v2" title="arxiv.org access"> <button class="ui compact blue labeled icon button serp-button"> <i class="file alternate outline icon"></i> arxiv.org </button> </a>

Joint T1 and T2 Mapping with Tiny Dictionaries and Subspace-Constrained Reconstruction [article]

Volkert Roeloffs, Martin Uecker, Jens Frahm
<span title="2018-12-22">2018</span> <i > arXiv </i> &nbsp; <span class="release-stage" >pre-print</span>
Purpose: To develop a method that adaptively generates tiny dictionaries for joint T1-T2 mapping. Theory: This work breaks the bond between dictionary size and representation accuracy (i) by approximating the Bloch-response manifold by piece-wise linear functions and (ii) by adaptively refining the sampling grid depending on the locally-linear approximation error. Methods: Data acquisition was accomplished with use of an 2D radially sampled Inversion-Recovery Hybrid-State Free Precession
more &raquo; ... e. Adaptive dictionaries are generated with different error tolerances and compared to a heuristically designed dictionary. Based on simulation results, tiny dictionaries were used for T1-T2 mapping in phantom and in vivo studies. Reconstruction and parameter mapping were performed entirely in subspace. Results: All experiments demonstrated excellent agreement between the proposed mapping technique and template matching using heuristic dictionaries. Conclusion: Adaptive dictionaries in combination with manifold projection allow to reduce the necessary dictionary sizes by one to two orders of magnitude.
<span class="external-identifiers"> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/1812.09560v1">arXiv:1812.09560v1</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/mfr2nvwxl5c6vgjl7dw6zg2oia">fatcat:mfr2nvwxl5c6vgjl7dw6zg2oia</a> </span>
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In silico modeling for personalized stenting in aortic coarctation [article]

Dandan Ma, Yong Wang, Mueed Azhar, Ansgar Adler, Michael Steinmetz, Martin Uecker
<span title="2022-05-09">2022</span> <i > arXiv </i> &nbsp; <span class="release-stage" >pre-print</span>
Stent intervention is a recommended therapy to reduce the pressure gradient and restore blood flow for patients with coarctation of the aorta (CoA). In this work, we developed a framework for personalized stent intervention in CoA using in silico modeling, combining computational fluid dynamics (CFD) and image-based prediction of the geometry of the aorta after stent intervention. Firstly, the blood flow in the aorta, whose geometry was reconstructed from magnetic resonance imaging (MRI) data,
more &raquo; ... as numerically modeled using the lattice Boltzmann method (LBM). Both large eddy simulation (LES) and direct numerical simulation (DNS) were considered to adequately resolve the turbulent hemodynamics, with boundary conditions extracted from phase-contrast flow MRI. By comparing the results from CFD and 4D-Flow MRI in 3D-printed flow phantoms, we concluded that the LBM based LES is capable of obtaining accurate aortic flow with acceptable computational cost. In silico stent implantation for a patient with CoA was then performed by predicting the deformed geometry after stent intervention and predicting the blood flow. By evaluating the pressure drop and maximum wall shear stress, an optimal stent can be selected.
<span class="external-identifiers"> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/2205.04518v1">arXiv:2205.04518v1</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/2zbso7kamnaprnjmmsifg765qq">fatcat:2zbso7kamnaprnjmmsifg765qq</a> </span>
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Polar phonon anomalies in single crystalline TbScO3 [article]

Stanislav Kamba, Veronica Goian, Dmitry Nuzhnyy, Viktor Bovtun, Martin Kempa, Jan Prokleska, Margitta Bernhagen, Reinhard Uecker, Darrell G. Schlom
<span title="2012-08-10">2012</span> <i > arXiv </i> &nbsp; <span class="release-stage" >pre-print</span>
The crystal growth is described in detail by Uecker et al. 4 The crystal orientation allowed us Near-normal IR reflectivity spectra were obtained using a Fourier transform IR spectrometer Bruker IFS  ... 
<span class="external-identifiers"> <a target="_blank" rel="external noopener" href="https://arxiv.org/abs/1208.2119v1">arXiv:1208.2119v1</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/54bkgyauuzb4xccxyq5wjhwmgu">fatcat:54bkgyauuzb4xccxyq5wjhwmgu</a> </span>
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Real-Time Magnetic Resonance Imaging

Jens Frahm, Dirk Voit, Martin Uecker
<span title="">2019</span> <i title="Ovid Technologies (Wolters Kluwer Health)"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/4qrvn236tzhfhoegnbrbdxcgxe" style="color: black;">Investigative Radiology</a> </i> &nbsp;
The aim of this study is to evaluate a real-time magnetic resonance imaging (MRI) method that not only promises high spatiotemporal resolution but also practical robustness in a wide range of scientific and clinical applications.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1097/rli.0000000000000584">doi:10.1097/rli.0000000000000584</a> <a target="_blank" rel="external noopener" href="https://www.ncbi.nlm.nih.gov/pubmed/31261294">pmid:31261294</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/o6m4ftfmhndlbjqdqpqindcofa">fatcat:o6m4ftfmhndlbjqdqpqindcofa</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20200510093657/https://pure.mpg.de/rest/items/item_3181099_1/component/file_3181103/content" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/22/fe/22fe573b06e651ffe2ab9a03384d43f5a3640fd3.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1097/rli.0000000000000584"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="external alternate icon"></i> Publisher / doi.org </button> </a>

Strain Engineering of Ferroelectric Domains in KxNa1−xNbO3 Epitaxial Layers

Jutta Schwarzkopf, Dorothee Braun, Michael Hanke, Reinhard Uecker, Martin Schmidbauer
<span title="2017-08-16">2017</span> <i title="Frontiers Media SA"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/uunhnq4jsbhmpkcnw2uws7hiie" style="color: black;">Frontiers in Materials</a> </i> &nbsp;
ndgaO3 (schmibauer et al., 2012) srTiO3 (schmibauer et al., 2012) DyscO3 (Uecker et al., 2013) TbscO3 (Uecker et al., 2013) gdscO3 (Uecker et al., 2013) ndscO3 (Uecker et al., 2013  ...  The rare-earth scandates ReScO3 (Re = Dy, Tb, Gd, Sm, Nd) are all grown at the Leibniz Institute for Crystal Growth (Uecker et al., 2006 (Uecker et al., , 2008 (Uecker et al., , 2013 Coh et al., 2010  ... 
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.3389/fmats.2017.00026">doi:10.3389/fmats.2017.00026</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/mneeli5wp5fcff2jbxio75kctm">fatcat:mneeli5wp5fcff2jbxio75kctm</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20190305130259/http://pdfs.semanticscholar.org/c9ed/451f32629bc6ce58a3d0b1cbdd8014304ab5.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/c9/ed/c9ed451f32629bc6ce58a3d0b1cbdd8014304ab5.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.3389/fmats.2017.00026"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="unlock alternate icon" style="background-color: #fb971f;"></i> frontiersin.org </button> </a>

Real-time MRI: recent advances using radial FLASH

Martin Uecker, Shuo Zhang, Dirk Voit, Klaus-Dietmar Merboldt, Jens Frahm
<span title="">2012</span> <i title="OMICS Publishing Group"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/ne3thawvcjgurcclzhm56cleve" style="color: black;">Imaging in Medicine</a> </i> &nbsp;
real-time MRI methods allow for hitherto inaccessible studies, lead to more robust and shorter examinations, improve patient comfort and offer new diagnostic opportunities. 462 future science group REVIEW Uecker  ...  future science groupReal-time MRI REVIEW future science group REVIEW Uecker, Zhang, Voit, Merboldt & Frahm  ... 
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.2217/iim.12.32">doi:10.2217/iim.12.32</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/na5imigvfbdtfk6pioigouzpa4">fatcat:na5imigvfbdtfk6pioigouzpa4</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20200318113605/https://www.openaccessjournals.com/articles/realtime-mri-recent-advances-using-radial-flash.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/ef/ac/efac6cce4fa95ad9a96b6619ee14f653705d5939.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.2217/iim.12.32"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="external alternate icon"></i> Publisher / doi.org </button> </a>

Perturbation theory for plasmonic eigenvalues

Daniel Grieser, Hannes Uecker, Svend-Age Biehs, Oliver Huth, Felix Rüting, Martin Holthaus
<span title="2009-12-04">2009</span> <i title="American Physical Society (APS)"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/lqjgbsoa65gghi2p2esulcqqqm" style="color: black;">Physical Review B</a> </i> &nbsp;
We develop a perturbative approach for calculating, within the quasistatic approximation, the shift of surface resonances in response to a deformation of a dielectric volume. Our strategy is based on the conversion of the homogeneous system for the potential which determines the plasmonic eigenvalues into an inhomogeneous system for the potential's derivative with respect to the deformation strength, and on the exploitation of the corresponding compatibility condition. The resulting general
more &raquo; ... ession for the first-order shift is verified for two explicitly solvable cases, and for a realistic example of a deformed nanosphere. It can be used for scanning the huge parameter space of possible shape fluctuations with only quite small computational effort.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1103/physrevb.80.245405">doi:10.1103/physrevb.80.245405</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/sfl3sxfasndebfthzvewa43acu">fatcat:sfl3sxfasndebfthzvewa43acu</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20170809024006/http://www.condmat.uni-oldenburg.de/Biehs/pubs/p_prb09.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/5c/b8/5cb881c9e7bf6865b82b611093f5e74ccf350337.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1103/physrevb.80.245405"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="external alternate icon"></i> aps.org </button> </a>

Parallel imaging with nonlinear reconstruction using variational penalties

Florian Knoll, Christian Clason, Kristian Bredies, Martin Uecker, Rudolf Stollberger
<span title="2011-06-27">2011</span> <i title="Wiley"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/34p2n5u2vjfgrf7j2rmkmfhogu" style="color: black;">Magnetic Resonance in Medicine</a> </i> &nbsp;
A new approach based on nonlinear inversion for autocalibrated parallel imaging with arbitrary sampling patterns is presented. By extending the iteratively regularized Gauss-Newton method with variational penalties, the improved reconstruction quality obtained from joint estimation of image and coil sensitivities is combined with the superior noise suppression of total variation and total generalized variation regularization. In addition, the proposed approach can lead to enhanced removal of
more &raquo; ... pling artifacts arising from pseudorandom and radial sampling patterns. This is demonstrated for phantom and in-vivo measurements. THEORY Mathematically, parallel MR imaging can be formulated as a nonlinear inverse problem where the sampling operator (defined by the k-space trajectory, e.g., Fourier transform followed by multiplication with a binary mask in the case of standard Cartesian subsampling) and the correspondingly acquired k-space data g = (g 1 , ..., g N ) T from N receiver coils are given, and the spin density u and the unknown (or not perfectly known) set of coil sensitivities c = (c 1 , ..., c N ) T have to be found such that [1] holds. As was shown in (3, 8) , this problem can be solved using the iteratively regularized Gauss-Newton (IRGN) method (28-31), i.e., computing in each step k for given x k := (u k , c k ) the solution δx:= (δu, δc) of the minimization problem Knoll et al.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1002/mrm.22964">doi:10.1002/mrm.22964</a> <a target="_blank" rel="external noopener" href="https://www.ncbi.nlm.nih.gov/pubmed/21710612">pmid:21710612</a> <a target="_blank" rel="external noopener" href="https://pubmed.ncbi.nlm.nih.gov/PMC4011127/">pmcid:PMC4011127</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/hzre7faevrbh3b24r3brnejs2e">fatcat:hzre7faevrbh3b24r3brnejs2e</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20200207001125/http://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC4011127&amp;blobtype=pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/44/15/4415cf9985711e20ce2c90db6b9f2d8ba53a7f2d.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1002/mrm.22964"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="external alternate icon"></i> wiley.com </button> </a> <a target="_blank" rel="external noopener" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4011127" title="pubmed link"> <button class="ui compact blue labeled icon button serp-button"> <i class="file alternate outline icon"></i> pubmed.gov </button> </a>

Real-time MRI at a resolution of 20 ms

Martin Uecker, Shuo Zhang, Dirk Voit, Alexander Karaus, Klaus-Dietmar Merboldt, Jens Frahm
<span title="2010-08-27">2010</span> <i title="Wiley"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/rr3xugvwirasdcilw2b3upxqpi" style="color: black;">NMR in Biomedicine</a> </i> &nbsp;
The desire to visualize noninvasively physiological processes at high temporal resolution has been a driving force for the development of MRI since its inception in 1973. In this article, we describe a unique method for real-time MRI that reduces image acquisition times to only 20 ms. Although approaching the ultimate limit of MRI technology, the method yields high image quality in terms of spatial resolution, signal-to-noise ratio and the absence of artifacts. As proposed previously, a fast
more &raquo; ... -angle shot (FLASH) gradient-echo MRI technique (which allows for rapid and continuous image acquisitions) is combined with a radial encoding scheme (which offers motion robustness and moderate tolerance to data undersampling) and, most importantly, an iterative image reconstruction by regularized nonlinear inversion (which exploits the advantages of parallel imaging with multiple receiver coils). In this article, the extension of regularization and filtering to the temporal domain exploits consistencies in successive data acquisitions and thereby enhances the degree of radial undersampling in a hitherto unexpected manner by one order of magnitude. The results obtained for turbulent flow, human speech production and human heart function demonstrate considerable potential for real-time MRI studies of dynamic processes in a wide range of scientific and clinical settings. Abbreviations used: FFT, fast Fourier transform; FLASH, fast low-angle shot; FOV, field of view; GPU, graphical processing unit; RF, radiofrequency; SNR, signal-to-noise ratio. NMR Biomed. 2010; 23: 986-994 View this article online at wileyonlinelibrary.com REAL-TIME MRI AT 20-MS RESOLUTION Figure 6 . Real-time MRI of the human heart at a resolution of 30 ms. The short-axis views (24 successive frames ¼ 720 ms) were obtained from a healthy subject during free breathing, and extend over about three-quarters of a cardiac cycle from diastole (top left) to systole (lower right). Individual images (in-plane resolution, 2.0 mm; section thickness, 8 mm) were acquired within 30 ms (15 spokes, TR ¼ 2.0 ms), corresponding to a rate of 33 frames per second. View this article online at wileyonlinelibrary.com
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1002/nbm.1585">doi:10.1002/nbm.1585</a> <a target="_blank" rel="external noopener" href="https://www.ncbi.nlm.nih.gov/pubmed/20799371">pmid:20799371</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/cpdtif2xpfe63ozcazxkplvihu">fatcat:cpdtif2xpfe63ozcazxkplvihu</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20170816090523/http://pubman.mpdl.mpg.de/pubman/item/escidoc:587599/component/escidoc:2166988/587599.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/0a/48/0a4890f9137c3de346da848efb9acfbe4e2f028b.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1002/nbm.1585"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="external alternate icon"></i> wiley.com </button> </a>

Inverse reconstruction method for segmented multishot diffusion-weighted MRI with multiple coils

Martin Uecker, Alexander Karaus, Jens Frahm
<span title="">2009</span> <i title="Wiley"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/34p2n5u2vjfgrf7j2rmkmfhogu" style="color: black;">Magnetic Resonance in Medicine</a> </i> &nbsp;
Each k-space segment in multishot diffusion-weighted MRI is affected by a different spatially varying phase which is caused by unavoidable motions and amplified by the diffusionencoding gradients. A proper image reconstruction therefore requires phase maps for each segment. Such maps are commonly derived from two-dimensional navigators at relatively low resolution but do not offer robust solutions. For example, phase variations in diffusion-weighted MRI of the brain are often characterized by
more &raquo; ... gh spatial frequencies. To overcome this problem, an inverse reconstruction method for segmented multishot diffusion-weighted MRI is described that takes advantage of the full k-space data acquired from multiple receiver coils. First, the individual coil sensitivities are determined from the non-diffusion-weighted acquisitions by regularized nonlinear inversion. These coil sensitivities are then used to estimate accurate motion-associated phase maps for each segment by iterative linear inversion. Finally, the coil sensitivities and phase maps serve to reconstruct artifact-free images of the object by iterative linear inversion, taking advantage of the data of all segments. The efficiency of the new method is demonstrated for segmented diffusion-weighted stimulated echo acquisition mode MRI of the human brain.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1002/mrm.22126">doi:10.1002/mrm.22126</a> <a target="_blank" rel="external noopener" href="https://www.ncbi.nlm.nih.gov/pubmed/19780170">pmid:19780170</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/apcxfrt6wfbqpittjrqhsalsx4">fatcat:apcxfrt6wfbqpittjrqhsalsx4</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20170818060316/http://pubman.mpdl.mpg.de/pubman/item/escidoc:587943/component/escidoc:2218769/587943.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/4f/05/4f052182a06e62a60a4e74b6b061ac743dbaa81b.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1002/mrm.22126"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="external alternate icon"></i> wiley.com </button> </a>

Fast Real-Time Cardiac MRI: a Review of Current Techniques and Future Directions

Xiaoqing Wang, Martin Uecker, Li Feng
<span title="">2021</span> <i title="Korean Society of Magnetic Resonance in Medicine"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/w3v7oxwwuvgpzijg5z7zsdnf7i" style="color: black;">Investigative Magnetic Resonance Imaging</a> </i> &nbsp;
Cardiac magnetic resonance imaging (MRI) serves as a clinical gold-standard noninvasive imaging technique for the assessment of global and regional cardiac function. Conventional cardiac MRI is limited by the long acquisition time, the need for ECG gating and/or long breathhold, and insufficient spatiotemporal resolution. Real-time cardiac cine MRI refers to high spatiotemporal cardiac imaging using data acquired continuously without synchronization or binning, and therefore of potential
more &raquo; ... t in overcoming the limitations of conventional cardiac MRI. Novel acquisition and reconstruction techniques must be employed to facilitate real-time cardiac MRI. The goal of this study is to discuss methods that have been developed for realtime cardiac MRI. In particular, we classified existing techniques into two categories based on the use of non-iterative and iterative reconstruction. In addition, we present several research trends in this direction, including deep learning-based image reconstruction and other advanced real-time cardiac MRI strategies that reconstruct images acquired from real-time free-breathing techniques.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.13104/imri.2021.25.4.252">doi:10.13104/imri.2021.25.4.252</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/75fc433arjhd5krviykot7qyou">fatcat:75fc433arjhd5krviykot7qyou</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20220201030013/https://i-mri.org/Synapse/Data/PDFData/1040IMRI/imri-25-252.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/73/ac/73ac37ef8bb39a6169ea5c74c50ef16015eea7fd.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.13104/imri.2021.25.4.252"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="external alternate icon"></i> Publisher / doi.org </button> </a>

Suppression of MRI Truncation Artifacts Using Total Variation Constrained Data Extrapolation

Kai Tobias Block, Martin Uecker, Jens Frahm
<span title="">2008</span> <i title="Hindawi Limited"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/a5p2e7p4xfg23hvv3wca3cde5u" style="color: black;">International Journal of Biomedical Imaging</a> </i> &nbsp;
The finite sampling ofk-space in MRI causes spurious image artifacts, known as Gibbs ringing, which result from signal truncation at the border ofk-space. The effect is especially visible for acquisitions at low resolution and commonly reduced by filtering at the expense of image blurring. The present work demonstrates that the simple assumption of a piecewise-constant object can be exploited to extrapolate the data ink-space beyond the measured part. The method allows for a significant
more &raquo; ... n of truncation artifacts without compromising resolution. The assumption translates into a total variation minimization problem, which can be solved with a nonlinear optimization algorithm. In the presence of substantial noise, a modified approach offers edge-preserving denoising by allowing for slight deviations from the measured data in addition to supplementing data. The effectiveness of these methods is demonstrated with simulations as well as experimental data for a phantom and human brain in vivo.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1155/2008/184123">doi:10.1155/2008/184123</a> <a target="_blank" rel="external noopener" href="https://www.ncbi.nlm.nih.gov/pubmed/18784847">pmid:18784847</a> <a target="_blank" rel="external noopener" href="https://pubmed.ncbi.nlm.nih.gov/PMC2531202/">pmcid:PMC2531202</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/ovupyilarfdirpkuhqpkktvgoa">fatcat:ovupyilarfdirpkuhqpkktvgoa</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20170809150918/http://cds.ismrm.org/ismrm-2008/files/01477.pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/3b/ae/3baee907742fbd68360b62700b2a81b340e56ce1.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1155/2008/184123"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="unlock alternate icon" style="background-color: #fb971f;"></i> hindawi.com </button> </a> <a target="_blank" rel="external noopener" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2531202" title="pubmed link"> <button class="ui compact blue labeled icon button serp-button"> <i class="file alternate outline icon"></i> pubmed.gov </button> </a>

A Multi-GPU Programming Library for Real-Time Applications [chapter]

Sebastian Schaetz, Martin Uecker
<span title="">2012</span> <i title="Springer Berlin Heidelberg"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/2w3awgokqne6te4nvlofavy5a4" style="color: black;">Lecture Notes in Computer Science</a> </i> &nbsp;
We present MGPU, a C++ programming library targeted at single-node multi-GPU systems. Such systems combine disproportionate floating point performance with high data locality and are thus well suited to implement real-time algorithms. We describe the library design, programming interface and implementation details in light of this specific problem domain. The core concepts of this work are a novel kind of container abstraction and MPI-like communication methods for intra-system communication.
more &raquo; ... further demonstrate how MGPU is used as a framework for porting existing GPU libraries to multi-device architectures. Putting our library to the test, we accelerate an iterative non-linear image reconstruction algorithm for real-time magnetic resonance imaging using multiple GPUs. We achieve a speed-up of about 1.7 using 2 GPUs and reach a final speed-up of 2.1 with 4 GPUs. These promising results lead us to conclude that multi-GPU systems are a viable solution for real-time MRI reconstruction as well as signal-processing applications in general.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1007/978-3-642-33078-0_9">doi:10.1007/978-3-642-33078-0_9</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/kcur6mssxbg2pjmttin3d3kkaq">fatcat:kcur6mssxbg2pjmttin3d3kkaq</a> </span>
<a target="_blank" rel="noopener" href="https://archive.org/download/arxiv-1301.1215/1301.1215.pdf" title="fulltext PDF download [not primary version]" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> File Archive [PDF] <span style="color: #f43e3e;">&#10033;</span> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1007/978-3-642-33078-0_9"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="external alternate icon"></i> springer.com </button> </a>

T2shuffling: Sharp, multicontrast, volumetric fast spin-echo imaging

Jonathan I. Tamir, Martin Uecker, Weitian Chen, Peng Lai, Marcus T. Alley, Shreyas S. Vasanawala, Michael Lustig
<span title="2016-01-20">2016</span> <i title="Wiley"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/34p2n5u2vjfgrf7j2rmkmfhogu" style="color: black;">Magnetic Resonance in Medicine</a> </i> &nbsp;
Purpose-A new acquisition and reconstruction method called T 2 Shuffling is presented for volumetric fast spin-echo (3D FSE) imaging. T 2 Shuffling reduces blurring and recovers many images at multiple T 2 contrasts from a single acquisition at clinically feasible scan times (6 to 7 minutes). Theory and Methods-The parallel imaging forward model is modified to account for temporal signal relaxation during the echo train. Scan efficiency is improved by acquiring data during the transient signal
more &raquo; ... ecay and by increasing echo train lengths without loss in SNR. By (1) randomly shuffling the phase encode view ordering, (2) constraining the temporal signal evolution to a low-dimensional subspace, and (3) promoting spatio-temporal correlations through locally low rank regularization, a time series of virtual echo time images is recovered from a single scan. A convex formulation is presented that is robust to partial voluming and RF field inhomogeneity. Results-Retrospective under-sampling and in vivo scans confirm the increase in sharpness afforded by T 2 Shuffling. Multiple image contrasts are recovered and used to highlight pathology in pediatric patients. A proof-of-principle method is integrated into a clinical musculoskeletal imaging workflow. Conclusion- The proposed T 2 Shuffling method improves the diagnostic utility of 3D FSE by reducing blurring and producing multiple image contrasts from a single scan.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1002/mrm.26102">doi:10.1002/mrm.26102</a> <a target="_blank" rel="external noopener" href="https://www.ncbi.nlm.nih.gov/pubmed/26786745">pmid:26786745</a> <a target="_blank" rel="external noopener" href="https://pubmed.ncbi.nlm.nih.gov/PMC4990508/">pmcid:PMC4990508</a> <a target="_blank" rel="external noopener" href="https://fatcat.wiki/release/5hpa5slrdnbwtdjxp64jglr7l4">fatcat:5hpa5slrdnbwtdjxp64jglr7l4</a> </span>
<a target="_blank" rel="noopener" href="https://web.archive.org/web/20200205231506/http://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC4990508&amp;blobtype=pdf" title="fulltext PDF download" data-goatcounter-click="serp-fulltext" data-goatcounter-title="serp-fulltext"> <button class="ui simple right pointing dropdown compact black labeled icon button serp-button"> <i class="icon ia-icon"></i> Web Archive [PDF] <div class="menu fulltext-thumbnail"> <img src="https://blobs.fatcat.wiki/thumbnail/pdf/bf/4d/bf4d8597f7b5db1cb9809df34e8f27e921235a88.180px.jpg" alt="fulltext thumbnail" loading="lazy"> </div> </button> </a> <a target="_blank" rel="external noopener noreferrer" href="https://doi.org/10.1002/mrm.26102"> <button class="ui left aligned compact blue labeled icon button serp-button"> <i class="external alternate icon"></i> wiley.com </button> </a> <a target="_blank" rel="external noopener" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4990508" title="pubmed link"> <button class="ui compact blue labeled icon button serp-button"> <i class="file alternate outline icon"></i> pubmed.gov </button> </a>
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