PURPOSE To establish the extent to which representative cognitive functions in subjects undergoing magnetic resonance (MR) imaging are acutely impaired by static magnetic fields of varying field strengths. MATERIALS AND METHODS This study was approved by the local ethics committee, and informed consent was obtained from all subjects. In this single-blind… (More)
Increasing field strengths in MRI necessitate the examination of potential side effects. Previously reported results have been contradictory, possibly caused by imbalanced samples. We aimed to examine whether special groups of people are more prone to develop side effects that might have led to contradictory results in previous studies. We examined the… (More)
INTRODUCTION Recent advances have enabled fast magnetic resonance imaging (MRI) of solid materials. This development has opened up new applications for MRI, but, at the same time, uncovered new challenges. Previously, MRI-invisible materials like the housing of MRI detection coils are now readily depicted and either cause artifacts or lead to a decreased… (More)
This study aims to quantify the mean change of the effective transverse relaxation time T2(⁎) in active brain regions of human volunteers at field strengths of B0=3T and 7T. Besides the mono-exponential signal decay model an extended model is tested that considers mesoscopic field gradients across imaging voxels. Both models are checked for cross-talk and… (More)
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PURPOSE Precise temperature measurements in the magnetic field are indispensable for MR safety studies and for temperature calibration during MR-guided thermotherapy. In this work, the interference of two commonly used fiber-optical temperature measurement systems with the static magnetic field B0 was determined. METHODS Two fiber-optical temperature… (More)
BACKGROUND AND METHODS A liquid crystal display was modified for use inside a 7 T MR magnet. SNR measurements were performed using different imaging sequences with the monitor absent, present, or activated. fMRI with a volunteer was conducted using a visual stimulus. RESULTS AND DISCUSSION SNR was reduced by 3.7%/7.9% in echo planar/fast-spin echo images… (More)
The concept of stress is relevant to magnetic resonance imaging (MRI) examination in various ways. First, levels of stress to staff and patients have not been quantified in ultra-high magnetic fields. Second, research is increasingly interested in experimentally defining regional brain activity during stress. It is therefore important to know whether… (More)