Dynamic Parallel Imaging: New Method for Accelerated MR Imaging
Bildgebung und Mikroskopie
- Reliable and robust
- Many different implementations possible
- Uncomplicated integration process
- Cheap components usable
- Accelerated MR imaging
- MR imaging of dynamic samples
For spatially resolved MR signal detection linear magnetic field gradients are used to locate the origin of a signal. To further increase spatial resolution and processing time, modern MR scanners are additionally using multiple RF coils at different positions, with each of them having its individual sensitivity profile within the sample. For many applications typical imaging durations are still too long and further improvement of the spatial information is desired.
A new detection technique based on varying sensitivity profiles has been developed to overcome the aforementioned shortcomings and to further improve acquisition durations MR imaging. This approach represents an extension of the known parallel imaging method, where the individual sensitivity profiles of multiple RF coils are local and static. The use of dynamic instead of static sensitivity profiles offers additional spatial information that can be used for accelerated imaging.
The variation of the sensitivity profile can be achieved in various ways. One implementation of the invention is the use of adjustable capacitors, namely varactor diodes, as shown in the example schematic in figure 2a. The capacity of the diodes is adjusted by application of different voltages U1 to U6 to the diodes. With this arrangement the resulting sensitivity profiles of this coil can be modified dynamically.
Another possibility for varying sensitivity profiles is given using tunable metamaterials, as they have an adjustable dielectric permittivity and magnetic permeability. A possible arrangement using a separated profile modulation control unit (3) can be seen in figure 2b, where the metamaterial (4) is placed in between the sample (1) and the receive or transmit coil (2). As a third option (Fig. 2c), an auxiliary coil (5) arranged as a field shaping component with electro-magnetic coupling to one or more of the RF coils can be used.
EPO (EP2019191682), USPTO (US20210048493)
K. Scheffler, et al., "Spread‐spectrum magnetic resonance imaging" Magn Reson Med. 2019, 877–885 (2019)
- Ref.-No.: 0107-5654-BC (526,5 KiB)
Dr. Bernd Ctortecka, M. Phil.
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