MR Technology

MRI at extremely high fields requires a major effort in technical developments. A significant part of our research is thus devoted to capture as much as possible of the tiny magnetic waves emitted from the excited brain. We develop highly dedicated radio-frequency multi-channel transmit and receive arrays with optimized efficiency, receive performance and coverage. Further projects include local shim arrays, parallel transmit technology and ultra-low field MR with hyperpolarization.

Magnetic resonance (MR) images can be created noninvasively using only static and dynamic magnetic fields, and radio frequency pulses. MR imaging provides fast image acquisitions which have been clinically feasible only since the discovery of efficient MR sequences, ie. time-efficient application of two building blocks: radio frequency pulses and spatial magnetic field gradients. [more]
Subject motion is a major problem in functional and anatomical head MRI. The resulting artifacts such as ghosting and blurring may complicate image interpretation, or in the worst case, render acquired images useless. Thus, measurements have to be repeated or entire patient populations, such as elderly or pediatric patients, have to be excluded from certain studies. [more]
In conventional imaging, the scan of k-space (which is the Fourier transformed image space) is achieved by applying linear gradients along the principal axes. In most applications, k-space is acquired line by line on a Cartesian grid, or in some implementations along projections or spirals, to name just a few. [more]
System instabilities and physiological motion such as breathing and cardiac pulsation can cause signal fluctuations in gradient-echo scans. In spin-warp imaging (standard Cartesian acquisition), different phase offsets for each line of k-space can lead to severe ghosting in the image domain. [more]
Magnetic resonance current density imaging (MRCDI) and MR electrical impedance tomography (MREIT) are two emerging modalities, which combine weak time-varying currents injected via surface electrodes with magnetic resonance imaging (MRI) to acquire information about the current flow and ohmic conductivity distribution at high spatial resolution. [more]
In recent years, available field strengths for MRI instruments have increased rapidly, both for human and animal applications. While 7 Tesla (T) has developed into a standard field strength for ultra-high field MR in humans, the interest in even stronger magnets remains high, causing a slow but steady increase in scanners operating at 9.4T or above. [more]
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