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Tobias Kober

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Publications associées (151)

Prospective head motion correction using FID-guided on-demand image navigators

Reto Meuli, Rolf Gruetter, Bénédicte Marie Maréchal, Guillaume Bonnier, Gunnar Krüger, Tobias Kober, Tom Hilbert, Maryna Volodimirivna Waszak, Pavel Falkovskiy

PURPOSE: We suggest a motion correction concept that employs free-induction-decay (FID) navigator signals to continuously monitor motion and to guide the acquisition of image navigators for prospective motion correction following motion detection. METHODS: ...

Wiley-Blackwell2017

Comparison of accelerated T1-weighted whole-brain structural-imaging protocols

Jean-Philippe Thiran, Reto Meuli, Bénédicte Marie Maréchal, Tobias Kober, Alexis Roche, Pavel Falkovskiy

Imaging in neuroscience, clinical research and pharmaceutical trials often employs the 3D magnetisation-prepared rapid gradient-echo (MPRAGE) sequence to obtain structural T1-weighted images with high spatial resolution of the human brain. Typical research ...

Academic Press Inc Elsevier Science2016

An in vivo study of the orientation-dependent and independent components of transverse relaxation rates in white matter

Tobias Kober, José Pedro Rebelo Ferreira Marques, Tom Hilbert, Diana Khabipova

Diffusion-weighted imaging (DWI) provides information that allows the estimation of white-matter (WM) fibre orientation and distribution, but it does not provide information about myelin density, fibre concentration or fibre size within each voxel. On the ...

Wiley-Blackwell2016

Accuracy and Precision of Head Motion Information in Multi-Channel Free Induction Decay Navigators for Magnetic Resonance Imaging

Gunnar Krüger, Tobias Kober, Maryna Volodimirivna Waszak, Michael Herbst

Free induction decay (FID) navigators were found to qualitatively detect rigid-body head movements, yet it is unknown to what extent they can provide quantitative motion estimates. Here, we acquired FID navigators at different sampling rates and simultaneo ...

Ieee-Inst Electrical Electronics Engineers Inc2015

Prospective motion correction with FID-triggered image navigators

Jean-Philippe Thiran, Reto Meuli, Rolf Gruetter, Guillaume Bonnier, Gunnar Krüger, Tobias Kober, Tom Hilbert, Maryna Volodimirivna Waszak, Pavel Falkovskiy

2015

Quantitative comparison of cortical surface reconstructions from MP2RAGE and multi-echo MPRAGE data at 3 and 7 T

Tobias Kober

The Magnetization-Prepared 2 Rapid Acquisition Gradient Echo (MP2RAGE) method achieves spatially uniform contrast across the entire brain between gray matter and surrounding white matter tissue and cerebrospinal fluid by rapidly acquiring data at two point ...

Academic Press Inc Elsevier Science2014

Dielectric pads and low- B1+ adiabatic pulses: Complementary techniques to optimize structural T1w whole-brain MP2RAGE scans at 7 tesla

François Lazeyras, Gunnar Krüger, Tobias Kober, José Pedro Rebelo Ferreira Marques, Kieran O'Brien

Purpose To evaluate the combination of low-B1+ adiabatic pulses and high permittivity (εr ≈ 165) dielectric pads effectiveness to reproducibly improve the inversion efficiency for whole-brain MP2RAGE scans, at ultra-high field. Materials and Methods Two lo ...

Wiley-Blackwell2014

Improved temporal resolution for functional studies with reduced number of segments with three-dimensional echo planar imaging

Rolf Gruetter, Wietske Van der Zwaag, Tobias Kober, José Pedro Rebelo Ferreira Marques, Mayur Narsude

PURPOSE: To introduce a new k-space traversal strategy for segmented three-dimensional echo planar imaging (3D EPI) that encodes two partitions per radiofrequency excitation, effectively reducing the number excitations used to acquire a 3D EPI dataset by h ...

Wiley-Blackwell2014

FID-guided retrospective motion correction based on autofocusing

Rolf Gruetter, Gunnar Krüger, Tobias Kober, Cristina Granziera, Maryna Volodimirivna Waszak

This work investigates the possibility of using FID navigator signals to improve the performance of a recently proposed autofocusing-based retrospective motion correction technique. FID navigators were incorporated into an MP-RAGE sequence and 3 subjects w ...

2014

Robust T1-Weighted Structural Brain Imaging and Morphometry at 7T Using MP2RAGE

Patric Hagmann, François Lazeyras, Gunnar Krüger, Tobias Kober, José Pedro Rebelo Ferreira Marques, Alexis Roche, Kieran O'Brien

Purpose To suppress the noise, by sacrificing some of the signal homogeneity for numerical stability, in uniform T1 weighted (T1w) images obtained with the magnetization prepared 2 rapid gradient echoes sequence (MP2RAGE) and to compare the clinical utilit ...

Public Library of Science2014

A novel manipulation method of human body ownership using an fMRI-compatible master-slave system

Olaf Blanke, Wietske Van der Zwaag, Tobias Kober, Masayuki Hara, Giulio Rognini, Roy Salomon

Bodily self-consciousness has become an important topic in cognitive neuroscience aiming to understand how the brain creates a unified sensation of the self in a body. Specifically, full body illusion (FBI) in which changes in bodily self-consciousness are ...

Elsevier2014

Hybrid MP-RAGE Trajectory with FID Motion Detection and Self-Navigated Motion Correction (MoCoRAGE)

Gunnar Krüger, Tobias Kober, Davide Piccini

2013

A Connectome-Based Comparison of Diffusion MRI Schemes

Jean-Philippe Thiran, Xavier Gigandet, Patric Hagmann, Reto Meuli, Alessandra Griffa, Gunnar Krüger, Tobias Kober, Alessandro Daducci

Public Library of Science2013

Micro-Structural Brain Alterations in Aviremic HIV+ Patients with Minor Neurocognitive Disorders: A Multi-Contrast Study at High Field

Djalel Eddine Meskaldji, Reto Meuli, François Lazeyras, Gunnar Krüger, Tobias Kober, Cristina Granziera, Alessandro Daducci, Alexis Roche

Objective Mild neurocognitive disorders (MND) affect a subset of HIV+ patients under effective combination antiretroviral therapy (cART). In this study, we used an innovative multi-contrast magnetic resonance imaging (MRI) approach at high-field to assess ...

Public Library of Science2013

SA2RAGE: A new sequence for fast B(1) (+) -mapping

Rolf Gruetter, Florent Eggenschwiler, Tobias Kober, José Pedro Rebelo Ferreira Marques

At high magnetic field strengths (≥3T), the radiofrequency wavelength used in MRI is of the same order of magnitude of (or smaller than) the typical sample size, making transmit magnetic field (B 1+) inhomogeneities more prominent. Methods such as radiofre ...

Wiley2012

MP2RAGE multiple sclerosis magnetic resonance imaging at 3 T

Reto Meuli, Rolf Gruetter, Delphine Ribes Lemay, Gunnar Krüger, Tobias Kober, Cristina Granziera

Objectives: Lesion detection and characterization in multiple sclerosis (MS) are an essential part of its clinical diagnosis and an important research field. In this pilot study, we applied the recently introduced two inversion-contrast magnetization-prepa ...

2012

PACEUP-3DEPI: A highly Accelerated 3D-EPI Sequence for fMRI at 7T

Rolf Gruetter, Wietske Van der Zwaag, Tobias Kober, José Pedro Rebelo Ferreira Marques, Mayur Narsude

2012

Temporal SNR characteristics in segmented 3D-EPI at 7T

Rolf Gruetter, Wietske Van der Zwaag, Gunnar Krüger, Tobias Kober, José Pedro Rebelo Ferreira Marques

Three-dimensional segmented echo planar imaging (3D-EPI) is a promising approach for high-resolution functional magnetic resonance imaging, as it provides an increased signal-to-noise ratio (SNR) at similar temporal resolution to traditional multislice 2D- ...

Wiley-Blackwell2012

Prospective and retrospective motion correction in diffusion magnetic resonance imaging of the human brain

Rolf Gruetter, Gunnar Krüger, Tobias Kober

Diffusion-weighting in magnetic resonance imaging (MRI) increases the sensitivity to molecular Brownian motion, providing insight in the micro-environment of the underlying tissue types and structures. At the same time, the diffusion weighting renders the ...

Elsevier2012

Fluid and white matter suppression with the MP2RAGE sequence

Giulio Gambarota, Gunnar Krüger, Tobias Kober, José Pedro Rebelo Ferreira Marques

Purpose: To develop a magnetic resonance imaging (MRI) sequence (fluid and white matter suppression, FLAWS) for generating two sets of images from a single acquisition: one with contrast similar to a T1-weighted magnetization-prepared rapid gradient-echo s ...

Wiley-Blackwell2012

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