Publications by Özlem Ipek | EPFL Graph Search

Segmenting electroencephalography wires reduces radiofrequency shielding artifacts in simultaneous electroencephalography and functional magnetic resonance imaging at 7 T

Rolf Gruetter, João Pedro Forjaco Jorge, Thanh Phong Kevin Lê, Özlem Ipek

Purpose: Simultaneous scalp electroencephalography and functional magnetic resonance imaging (EEG-fMRI) enable noninvasive assessment of brain function with high spatial and temporal resolution. However, at ultra-high field, the data quality of both modali ...

Wiley2022

Brain NAD Is Associated With ATP Energy Production and Membrane Phospholipid Turnover in Humans

Rolf Gruetter, Lijing Xin, Maya Shevlyakova, Özlem Ipek

The brain requires a large amount of energy, mostly derived from the metabolism of glucose, which decreases substantially with age and neurological diseases. While mounting evidence in model organisms illustrates the central role of brain nicotinamide aden ...

FRONTIERS MEDIA SA2020

A human cerebral and cerebellar 8-channel transceive RF dipole coil array at 7T

Rolf Gruetter, Jérémie Daniel Clément, Özlem Ipek

PURPOSE: Dipole antennas that provide high transmit field penetration with large coverage, and their use in a parallel transmit setup, may be advantageous in minimizing B 1+ -field inhomogeneities at ultra-high field, i.e 7T. We have developed and evaluate ...

Wiley2019

Nutritional ketosis increases NAD plus /NADH ratio in healthy human brain: an in vivo study by P-31-MRS

Rolf Gruetter, Lijing Xin, Mojgan Masoodi, Özlem Ipek

SAGE PUBLICATIONS INC2019

A combined 32‐channel receive‐loops/8‐channel transmit‐dipoles coil array for whole‐brain MR imaging at 7T

Rolf Gruetter, Jérémie Daniel Clément, Özlem Ipek

Purpose Multichannel receive arrays provide high SNR and parallel‐imaging capabilities, while transmit‐only dipole arrays have been shown to achieve a large coverage of the whole‐brain including the cerebellum. The aim of this study was to develop and char ...

Wiley2019

Nutritional Ketosis Increases NAD+/NADH Ratio in Healthy Human Brain: An in Vivo Study by 31P-MRS

Nicolas Christinat, Rolf Gruetter, Lijing Xin, Maya Shevlyakova, Mojgan Masoodi, Özlem Ipek

Ketones represent an important alternative fuel for the brain under glucose hypo-metabolic conditions induced by neurological diseases or aging, however their metabolic consequences in healthy brains remain unclear. Here we report that ketones can increase ...

2018

Is Gd-DTPA Necessary in Clinical Practice for Peripheral Nerve Injury?

Özlem Ipek

2018

Clinical Neuroimaging Using 7 T MRI: Challenges and Prospects

François Lazeyras, Rolf Gruetter, Lijing Xin, Özlem Ipek, Pascal Martelli

The aim of this article is to illustrate the principal challenges, from the medical and technical point of view, associated with the use of ultrahigh field (UHF) scanners in the clinical setting and to present available solutions to circumvent these limita ...

2018

Radio-frequency coils for ultra-high field magnetic resonance

Özlem Ipek

Radiofrequency (RF) coils are key components of magnetic resonance imaging (MRI) systems. The primary purpose of this review is to provide a basic theory of RF coil designs and their characterization by bench measurements, electromagnetic field simulations ...

Elsevier2017

A double-quadrature radiofrequency coil design for proton-decoupled carbon-13 magnetic resonance spectroscopy in humans at 7T

Eulalia Serés Roig, Rolf Gruetter, Lijing Xin, Guillaume Donati, Özlem Ipek

Purpose Carbon-13 magnetic resonance spectroscopy (13C-MRS) is challenging because of the inherent low sensitivity of 13C detection and the need for radiofrequency transmission at the 1H frequency while receiving the 13C signal, the latter requiring electr ...

Wiley-Blackwell2015

Single acquisition electrical property mapping based on relative coil sensitivities: A proof-of-concept demonstration

Rolf Gruetter, José Pedro Rebelo Ferreira Marques, Özlem Ipek

All methods presented to date to map both conductivity and permittivity rely on multiple acquisitions to compute quantitatively the magnitude of radiofrequency transmit fields, B1+. In this work, we propose a method to compute both conductivity and permitt ...

Wiley-Blackwell2015

Simultaneous EEG–fMRI at ultra-high field: Artifact prevention and safety assessment

Rolf Gruetter, Wietske Van der Zwaag, João Pedro Forjaco Jorge, Patricia Figueiredo, Özlem Ipek

The simultaneous recording of scalp electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) can provide unique insights into the dynamics of human brain function, and the increased functional sensitivity offered by ultra-high field fM ...

Elsevier2015