New technology in designing human head RF coils for UHF MRI: Dipole antennas

In two decades since ultra-high field (UHF, ≥7T) MRI scanners became available to the research community, they have provided evidence of undisputable benefits of UHF MR imaging including substantial increase of signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Further advancement of UHF MRI still heavily depends on development of novel hardware designs including its very important components, i.e. radio frequency (RF) coils. Major limitations of current RF coil designs for human head imaging at UHF are the inhomogeneity and poor longitudinal coverage (along the coil and magnet axis) of the transmit (Tx) RF field as well as high local tissue heating, which is commonly evaluated by calculating the peak of the local specific absorption rate (pSAR). In addition, increasing the number of surface loops in a human head receive (Rx) array improves the peripheral signal-to-noise ratio (SNR), while SNR near the brain center doesn’t substantially change. Recent theoretical works demonstrated that an optimal central SNR at UHF requires contribution of two current patterns associated with a combination of surface loops and dipole antennas.

After quickly reviewing the backdrop of RF coil engineering, in this talk, I will present several RF array head coils recently developed in our lab to optimize Tx-performance and SNR at UHF. Presented coils are all based on using novel dipole antenna designs including so-called bent folded-end and coaxial dipoles and their combination with common surface loops.

High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany

The lecture will be held in sitem-insel (Room O2.211), Freiburgstr. 3, Bern followed by an Apéro and discussion

and zoom https://unibe-ch.zoom.us/j/66256483922?pwd=aE1kTFg5aUZza1JmWEJxZDVsdnV5dz09

Please feel free to spread the word to anybody potentially interested.

For further info please contact: karin.zwygart@insel.ch