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Gunnar Krüger

Cette personne n’est plus à l’EPFL

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Publications associées (60)

Testing the variability of Diffusion Spectrum Imaging (DSI): Inter- and intra-site comparison on "identical" 3T scanners

Jean-Philippe Thiran, Reto Meuli, François Lazeyras, Alia Lemkaddem, Gunnar Krüger, Alessandro Daducci

Multi-center neuroimaging studies have more power than smaller ones to conduct sophisticated studies of basic neuroanatomy and clinical disorders. One important confound of combining images obtained from different scanners is the potential for scanner effe ...

2011

Effects of hardware heterogeneity on the performance of SVM Alzheimer's disease classifier

Bénédicte Marie Maréchal, Gunnar Krüger, Ahmed Abdulkadir

Fully automated machine learning methods based on structural magnetic resonance imaging data can assist radiologists in the diagnosis of Alzheimer's disease (AD). These algorithms require large data sets to learn the separation of subjects with and without ...

Elsevier2011

On the Convergence of EM-Like Algorithms for Image Segmentation using Markov Random Fields

Meritxell Bach Cuadra, Delphine Ribes Lemay, Gunnar Krüger, Alexis Roche

Inference of Markov random field images segmentation models is usually performed using iterative methods which adapt the well-known expectation-maximization (EM) algorithm for independent mixture models. However, some of these adaptations are ad-hoc and ma ...

2011

Head Motion Detection Using FID Navigators

Rolf Gruetter, Gunnar Krüger, Tobias Kober, José Pedro Rebelo Ferreira Marques

This work explores a concept for motion detection in brain MR examinations using high channel-count RF coil arrays. It applies ultrashort (< 100 mu sec) free induction decay signals, making use of the knowledge that motion induces variations in these signa ...

Wiley-Blackwell2011

Diffusion Spectrum Imaging after stroke shows structural changes in the contra-lateral motor network correlating with functional recovery

Jean-Philippe Thiran, Djalel Eddine Meskaldji, Xavier Gigandet, Reto Meuli, Gunnar Krüger, Cristina Granziera, Alessandro Daducci, Leila Cammoun

There is growing interest in understanding the role of the non-injured contra-lateral hemisphere in stroke recovery. In the experimental field, histological evidence has been reported that structural changes occur in the contra-lateral connectivity and cir ...

2011

Who said fat is bad? Skull-stripping benefits from additional fat image

Reto Meuli, Delphine Ribes Lemay, Gunnar Krüger, Tobias Kober

Being a preliminary step for many clinical applications and analyses, accurate skull-stripping is a key challenge in MR brain imaging. One of its major difficulties arises from the contrast similarities at brain/non-brain tissue interfaces, in particular b ...

2011

MP2RAGE, a self bias-field corrected sequence for improved segmentation and T-1-mapping at high field

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

The large spatial inhomogeneity in transmit B, field (B-1(+)) observable in human MR images at hi h static magnetic fields (B-0) severely impairs image quality. To overcome this effect in brain T-1-weighted images the, MPRAGE sequence was modified to gener ...

Elsevier2010

On the reproducibility and anatomical correspondence of DSI tractography

Jean-Philippe Thiran, Xavier Gigandet, Patric Hagmann, Reto Meuli, Gunnar Krüger, Cristina Granziera, Alessandro Daducci, Leila Cammoun

Diffusion spectrum imaging (DSI) is increasingly explored in clinical research. The quantitative value of the DSI technique, however, has still to be established. In this context, a better understanding of the reproducibility and the anatomical corresponde ...

2010

Eddy current effects on a clinical 7T-68 cm bore scanner

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

Eddy currents induced by switching of magnetic field gradients can lead to distortions in short echo-time spectroscopy or diffusion weighted imaging. In small bore magnets, such as human head-only systems, minimization of eddy current effects is more deman ...

2010

Cerebellar Cortical Layers: In Vivo Visualization with Structural High-Field-Strength MR Imaging

Rolf Gruetter, Wietske Van der Zwaag, Gunnar Krüger, José Pedro Rebelo Ferreira Marques, Cristina Granziera

Purpose: To perform in vivo imaging of the cerebellum with an in-plane resolution of 120 mm to observe its cortical granular and molecular layers by taking advantage of the high signal-to-noise ratio and the increased magnetic susceptibility-related contra ...

2010

NMR Properties of Human Median Nerve at 3 T: Proton Density, T1, T2, and Magnetization Transfer

Giulio Gambarota, Gunnar Krüger

Purpose: To measure the proton density (PD), the T1 and T2 relaxation time, and magnetization transfer (MT) effects in human median nerve at 3 T and to compare them with the corresponding values in muscle. ...

Wiley-Blackwell2009

Automatic quality assessment in structural brain magnetic resonance imaging

Jean-Philippe Thiran, Reto Meuli, Bénédicte Marie Maréchal, Gunnar Krüger

MRI has evolved into an important diagnostic technique in medical imaging. However, reliability of the derived diagnosis can be degraded by artifacts, which challenge both radiologists and automatic computer-aided diagnosis. This work proposes a fully-auto ...

Wiley2009

Comparison Of Single-Shot 2d EPI And Segmented 3d EVI Acquisition For fMRI at 7T

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

2009

In vivo measurement of glycine with short echo-time H-1 MRS in human brain at 7 T

Rolf Gruetter, Giulio Gambarota, Lijing Xin, Wietske Van der Zwaag, Gunnar Krüger

To determine whether glycine can be measured at 7 T in human brain with H-1 magnetic resonance spectroscopy (MRS). ...

2009

MP2RAGE contrast optimization at 7T and applications

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

2009

Automatic quality assessment in structural brain magnetic resonance imaging

Jean-Philippe Thiran, Reto Meuli, Bénédicte Marie Maréchal, Gunnar Krüger

Quality assessment of MRI is of great importance to derive reliable diagnostic information. As automated quantitative image analysis is being increasingly used in routine, automated measures of quality are needed. Based on a single magnitude image, we prop ...

2009

Motion detection using FID navigator signals of MRI coil array elements

Rolf Gruetter, Gunnar Krüger, Tobias Kober, José Pedro Rebelo Ferreira Marques

We propose a motion-detection technique which, in contrast to previously suggested methods, is based on motion-induced free induction decay (FID) signal changes in receive coil arrays with negligible impact on scanning performance. ...

2009

MR Spectroscopy of the Human Brain With Enhanced Signal Intensity at Ultrashort Echo Times on a Clinical Platform at 3T and 7T

Rolf Gruetter, Giulio Gambarota, Gunnar Krüger

Recently, the spin-echo full-intensity acquired localized (SPECIAL) spectroscopy technique was proposed to unite the advantages of short TEs on the order of milliseconds (ms) with full sensitivity and applied to in vivo rat brain. In the present study, SPE ...

Wiley-Blackwell2009

Adaptive FID-navigators for respiration monitoring in multi-slice fMRI applications

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

Functional magnetic resonance imaging (fMRI) measures activation-induced signal changes by means of the blood-oxygenation-level-depended (BOLD) contrast. Since signal changes are typically only 1-3%, the method is intrinsically sensitive to all signal inst ...

2008

High-Quality MR Spectroscopy of the Human Brain with Full Signal Intensity at Echo Times Below 6 ms on a Clinical Platform at 3T and 7T

Rolf Gruetter, Giulio Gambarota, Gunnar Krüger

2008

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