Výsledky vyhledávání - "S J Vannesjo"

Shim optimization with region of interest-specific Tikhonov regularization: Application to second-order slice-wise shimming of the brain

Autor: Stuart Clare, Yuhang Shi, S J Vannesjo

Publikováno v: Magnetic resonance in medicineREFERENCES. 87(3)

Purpose Slice-wise shimming can improve field homogeneity, but suffers from large noise propagation in the shim calculation. Here, we propose a robust shim current optimization for higher-order dynamic shim updating, based on Tikhonov regularization

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::fbbd794b58474ac839745a6f27674366
https://pubmed.ncbi.nlm.nih.gov/34783374

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Trace-based correction of breathing-induced field fluctuations in T2*-weighted imaging of the spinal cord

Autor: Lars Kasper, Stuart Clare, Irene Tracey, Karla L. Miller, S J Vannesjo

PurposeSpinal cord MRI at ultra-high field is hampered by time-varying magnetic fields associated with the breathing cycle, giving rise to ghosting artifacts in multi-shot acquisitions. Here, we suggest a correction approach based on linking the sign

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::9d28c715ba2a13b27aea913b9caf1d31
https://doi.org/10.1101/406371

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Image reconstruction using a gradient impulse response model for trajectory prediction

Autor: Maximilian Haeberlin, Julia Busch, Christoph Barmet, Lars Kasper, Klaas P. Pruessmann, Simon Gross, Nadine N. Graedel, S J Vannesjo

Publikováno v: Magnetic Resonance in Medicine. 76:45-58

Purpose Gradient imperfections remain a challenge in MRI, especially for sequences relying on long imaging readouts. This work aims to explore image reconstruction based on k-space trajectories predicted by an impulse response model of the gradient s

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::f20440a3c7fc5ba300b766d931e31136
https://doi.org/10.1002/mrm.25841

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Field camera measurements of gradient and shim impulse responses using frequency sweeps

Autor: S J Vannesjo, Christoph Barmet, Matteo Pavan, Bertram J. Wilm, Klaas P. Pruessmann, David O. Brunner, Benjamin E. Dietrich

Publikováno v: Magnetic Resonance in Medicine. 72:570-583

Purpose Applications of dynamic shimming require high field fidelity, and characterizing the shim field dynamics is therefore necessary. Modeling the system as linear and time-invariant, the purpose of this work was to measure the impulse response fu

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::a1195fcf48d587a0681293fb88393be6
https://doi.org/10.1002/mrm.24934

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Single-shot spiral imaging enabled by an expanded encoding model: Demonstration in diffusion MRI

Autor: Benjamin E. Dietrich, David O. Brunner, Klaas P. Pruessmann, Thomas Schmid, Maximilian Haeberlin, Christoph Barmet, S J Vannesjo, Bertram J. Wilm, Simon Gross, Lars Kasper

Publikováno v: Magnetic resonance in medicine. 77(1)

Purpose The purpose of this work was to improve the quality of single-shot spiral MRI and demonstrate its application for diffusion-weighted imaging. Methods Image formation is based on an expanded encoding model that accounts for dynamic magnetic fi

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7cda3805cdcf5be39bfe1c877e2ca7d7
https://pubmed.ncbi.nlm.nih.gov/27770473

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Fast iterative pre-emphasis calibration method enabling third-order dynamic shim updated fMRI

Autor: Anke Henning, A Fillmer, Klaas P. Pruessmann, Matteo Pavan, S J Vannesjo, Milan Scheidegger

Publikováno v: Magnetic Resonance in Medicine

PURPOSE: To calibrate a pre-emphasis to sufficiently compensate eddy currents for application of dynamic shim updating to fMRI without extension of scan times. METHODS: Eddy current effects induced into all shim terms up to third-order were character

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::28a903ac36fc37c35381863e95825355
https://www.zora.uzh.ch/id/eprint/120020/

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Gradient system characterization by impulse response measurements with a dynamic field camera

Autor: Matteo Pavan, Klaas P. Pruessmann, Lars Kasper, S J Vannesjo, Maximilan Haeberlin, Bertram J. Wilm, Christoph Barmet

Publikováno v: Magnetic Resonance in Medicine. 69:583-593

This work demonstrates a fast, sensitive method of characterizing the dynamic performance of MR gradient systems. The accuracy of gradient time-courses is often compromised by field imperfections of various causes, including eddy currents and mechani

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::136f6c502bc4a65614655d33a090935a
https://doi.org/10.1002/mrm.24263

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