Rosenzweig, Sebastian

[["dc.contributor.author","Rosenzweig, Sebastian"],["dc.date.accessioned","2019-01-25T09:31:58Z"],["dc.date.available","2019-01-25T09:31:58Z"],["dc.date.issued","2016"],["dc.description.abstract","Increasing imaging speed is of utmost importance in in-vivo magnetic resonance imaging (MRI). With simultaneous multi-slice (SMS) MRI we can simultaneously acquire several slices of an object, which allows for higher undersampling factors compared to single- or conventional multi-slice measurements by exploiting axial coil sensitivity information. In this thesis, we give a short introduction to the physical principles of MRI, cover the basics of a FLASH based SMS MRI sequence and perform tests to verify its accuracy: We check the fidelity of the slice distance as well as the flip angle and confirm the square-root-like signal-to-noise ratio benefit of SMS compared to conventional multi-slice experiments. A g-factor analysis is used to determine a favorable Cartesian undersampling scheme for multi-slice data. Common reconstruction strategies for SMS MRI make use of previously estimated coil sensitivities to solve a linear equation. Here, we propose a new method of SMS MRI based on Regularized Nonlinear Inversion (NLINV): SMS-NLINV. This method does not require a priori knowledge about the coil sensitivities and is attractive especially for real-time imaging where coil sensitivities may change due to motion or interactive changes to the slice position. We characterize the algorithm and present reconstructed phantom and in-vivo images."],["dc.identifier.arxiv","1612.05479v1"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/57386"],["dc.language.iso","en"],["dc.notes.status","fcwi"],["dc.title","Simultaneous multi-slice reconstruction by Regularized Nonlinear Inversion"],["dc.type","preprint"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1566"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Magnetic Resonance in Medicine"],["dc.bibliographiccitation.lastpage","1579"],["dc.bibliographiccitation.volume","81"],["dc.contributor.author","Roeloffs, Volkert"],["dc.contributor.author","Rosenzweig, Sebastian"],["dc.contributor.author","Holme, Hans Christian Martin"],["dc.contributor.author","Uecker, Martin"],["dc.contributor.author","Frahm, Jens"],["dc.date.accessioned","2020-05-13T13:45:33Z"],["dc.date.available","2020-05-13T13:45:33Z"],["dc.date.issued","2019"],["dc.description.abstract","Purpose A novel subspace‐based reconstruction method for frequency‐modulated balanced steady‐state free precession (fmSSFP) MRI is presented. In this work, suitable data acquisition schemes, subspace sizes, and efficiencies for banding removal are investigated. Theory and Methods By combining a fmSSFP MRI sequence with a 3D stack‐of‐stars trajectory, scan efficiency is maximized as spectral information is obtained without intermediate preparation phases. A memory‐efficient reconstruction routine is implemented by introducing the low‐frequency Fourier transform as a subspace which allows for the formulation of a convex reconstruction problem. The removal of banding artifacts is investigated by comparing the proposed acquisition and reconstruction technique to phase‐cycled bSSFP MRI. Aliasing properties of different undersampling schemes are analyzed and water/fat separation is demonstrated by reweighting the reconstructed subspace coefficients to generate virtual spectral responses in a post‐processing step. Results A simple root‐of‐sum‐of‐squares combination of the reconstructed subspace coefficients yields high‐SNR images with the characteristic bSSFP contrast but without banding artifacts. Compared to Golden‐Angle trajectories, turn‐based sampling schemes were superior in minimizing aliasing across reconstructed subspace coefficients. Water/fat separated images of the human knee were obtained by reweighting subspace coefficients. Conclusions The novel subspace‐based fmSSFP MRI technique emerges as a time‐efficient alternative to phase‐cycled bSFFP. The method does not need intermediate preparation phases, offers high SNR and avoids banding artifacts. Reweighting of the reconstructed subspace coefficients allows for generating virtual spectral responses with applications to water/fat separation."],["dc.identifier.arxiv","1803.06274v2"],["dc.identifier.doi","10.1002/mrm.27505"],["dc.identifier.pmid","30357904"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/65372"],["dc.language.iso","en"],["dc.relation.eissn","1522-2594"],["dc.relation.issn","0740-3194"],["dc.title","Frequency-modulated SSFP with radial sampling and subspace reconstruction: A time-efficient alternative to phase-cycled bSSFP"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2057"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Magnetic Resonance in Medicine"],["dc.bibliographiccitation.lastpage","2066"],["dc.bibliographiccitation.volume","79"],["dc.contributor.author","Rosenzweig, Sebastian"],["dc.contributor.author","Holme, Hans Christian Martin"],["dc.contributor.author","Wilke, Robin N."],["dc.contributor.author","Voit, Dirk"],["dc.contributor.author","Frahm, Jens"],["dc.contributor.author","Uecker, Martin"],["dc.date.accessioned","2018-01-17T13:51:59Z"],["dc.date.accessioned","2020-05-13T11:03:39Z"],["dc.date.available","2018-01-17T13:51:59Z"],["dc.date.available","2020-05-13T11:03:39Z"],["dc.date.issued","2017-08-24"],["dc.description.abstract","The development of a calibrationless parallel imaging method for accelerated simultaneous multi-slice (SMS) MRI based on Regularized Nonlinear Inversion (NLINV), evaluated using Cartesian and radial fast low-angle shot (FLASH)."],["dc.identifier.arxiv","1705.04135v2"],["dc.identifier.doi","10.1002/mrm.26878"],["dc.identifier.pmid","28840612"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/65299"],["dc.language.iso","en"],["dc.notes.status","zu prüfen"],["dc.relation.eissn","1522-2594"],["dc.relation.issn","0740-3194"],["dc.subject","Physics - Medical Physics"],["dc.subject","Physics - Medical Physics"],["dc.title","Simultaneous multi-slice MRI using cartesian and radial FLASH and regularized nonlinear inversion: SMS-NLINV"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1"],["dc.bibliographiccitation.journal","IEEE Transactions on Medical Imaging"],["dc.bibliographiccitation.lastpage","1"],["dc.contributor.author","Rosenzweig, Sebastian"],["dc.contributor.author","Scholand, Nick"],["dc.contributor.author","Holme, Hans Christian Martin"],["dc.contributor.author","Uecker, Martin"],["dc.date.accessioned","2020-05-13T12:33:50Z"],["dc.date.available","2020-05-13T12:33:50Z"],["dc.date.issued","2020"],["dc.description.abstract","Cardiac Magnetic Resonance Imaging (MRI) is time-consuming and error-prone. To ease the patient's burden and to increase the efficiency and robustness of cardiac exams, interest in methods based on continuous steady-state acquisition and self-gating has been growing in recent years. Self-gating methods extract the cardiac and respiratory signals from the measurement data and then retrospectively sort the data into cardiac and respiratory phases. Repeated breathholds and synchronization with the heart beat using some external device as required in conventional MRI are then not necessary. In this work, we introduce a novel self-gating method for radially acquired data based on a dimensionality reduction technique for time-series analysis (SSA-FARY). Building on Singular Spectrum Analysis, a zero-padded, time-delayed embedding of the auto-calibration data is analyzed using Principle Component Analysis. We demonstrate the basic functionality of SSA-FARY using numerical simulations and apply it to in-vivo cardiac radial single-slice bSSFP and Simultaneous Multi-Slice radiofrequency-spoiled gradientecho measurements, as well as to Stack-of-Stars bSSFP measurements. SSA-FARY reliably detects the cardiac and respiratory motion and separates it from noise. We utilize the generated signals for high-dimensional image reconstruction using parallel imaging and compressed sensing with in-plane wavelet and (spatio-)temporal total-variation regularization."],["dc.identifier.arxiv","1812.09057v6"],["dc.identifier.doi","10.1109/TMI.2020.2985994"],["dc.identifier.pmid","32275585"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/65361"],["dc.language.iso","en"],["dc.relation.eissn","1558-254X"],["dc.relation.issn","0278-0062"],["dc.title","Cardiac and Respiratory Self-Gating in Radial MRI using an Adapted Singular Spectrum Analysis (SSA-FARY)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","mrm.29521"],["dc.bibliographiccitation.journal","Magnetic Resonance in Medicine"],["dc.contributor.author","Wang, Xiaoqing"],["dc.contributor.author","Rosenzweig, Sebastian"],["dc.contributor.author","Roeloffs, Volkert"],["dc.contributor.author","Blumenthal, Moritz"],["dc.contributor.author","Scholand, Nick"],["dc.contributor.author","Tan, Zhengguo"],["dc.contributor.author","Holme, H. Christian M."],["dc.contributor.author","Unterberg‐Buchwald, Christina"],["dc.contributor.author","Hinkel, Rabea"],["dc.contributor.author","Uecker, Martin"],["dc.date.accessioned","2022-12-01T08:31:30Z"],["dc.date.available","2022-12-01T08:31:30Z"],["dc.date.issued","2022"],["dc.identifier.doi","10.1002/mrm.29521"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/118186"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-621"],["dc.relation.eissn","1522-2594"],["dc.relation.issn","0740-3194"],["dc.title","Free‐breathing myocardial T\n 1\n mapping using inversion‐recovery radial FLASH and motion‐resolved model‐based reconstruction"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.journal","Magnetic Resonance in Medicine"],["dc.contributor.author","Rosenzweig, Sebastian"],["dc.contributor.author","Holme, H. Christian M."],["dc.contributor.author","Uecker, Martin"],["dc.date.accessioned","2019-01-25T09:28:21Z"],["dc.date.available","2019-01-25T09:28:21Z"],["dc.date.issued","2018"],["dc.description.abstract","To develop a simple and robust tool for the estimation of gradient delays from highly undersampled radial k-space data."],["dc.identifier.arxiv","1805.04334v3"],["dc.identifier.doi","10.1002/mrm.27506"],["dc.identifier.pmid","30489652"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/57385"],["dc.language.iso","en"],["dc.notes.status","zu prüfen"],["dc.relation.eissn","1522-2594"],["dc.title","Simple auto-calibrated gradient delay estimation from few spokes using Radial Intersections (RING)"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","174701"],["dc.bibliographiccitation.issue","17"],["dc.bibliographiccitation.journal","The Journal of Chemical Physics"],["dc.bibliographiccitation.volume","142"],["dc.contributor.author","Geigenfeind, Thomas"],["dc.contributor.author","Rosenzweig, Sebastian"],["dc.contributor.author","Schmidt, Matthias"],["dc.contributor.author","Las Heras, Daniel de"],["dc.date.accessioned","2019-01-25T09:23:17Z"],["dc.date.available","2019-01-25T09:23:17Z"],["dc.date.issued","2015"],["dc.description.abstract","Using Monte Carlo simulation, we analyse the behaviour of two-dimensional hard rods in four different types of geometric confinement: (i) a slit pore where the particles are confined between two parallel walls with homeotropic anchoring; (ii) a hybrid slit pore formed by a planar and a homeotropic wall; square cavities that frustrate the orientational order by imposing either (iii) homeotropic or (iv) planar wall anchoring. We present results for the state diagram as a function of the packing fraction and the degree of confinement. Under extreme confinement, unexpected states appear with lower symmetries than those of the corresponding stable states in bulk, such as the formation of states that break the anchoring constraints or the symmetry imposed by the surfaces. In both types of square cavities, the particles form disclinations at intermediate densities. At high densities, however, the elastic stress is relaxed via the formation of domain walls where the director rotates abruptly by 90°."],["dc.identifier.arxiv","1502.03583v2"],["dc.identifier.doi","10.1063/1.4919307"],["dc.identifier.pmid","25956110"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/57384"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.relation.eissn","1089-7690"],["dc.title","Confinement of two-dimensional rods in slit pores and square cavities"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]