The study by Gregersen et al. on safety of a new setup for combined MRI and transcranial electric stimulation (TES) is now published in Brain Stimulation (https://www.sciencedirect.com/science/article/pii/S1935861X21000474).

Here, we propose using a very low-conductivity material for TES leads during TES-MRI experiments. This reduces the chances of adverse effects from RF-induced heating caused by the coupling between the RF field of the MR scanner and the high-conductivity lead wires typically used for TES. Safety of TES-MRI is usually ensured with twisted pair cables and one 5 kΩ resistor in each lead wire, causing restricted cable paths and limited stimulation currents. Restricted cable paths are especially damaging for Magnetic Resonance Current Density Imaging (MRCDI) as the stray magnetic fields from the cable currents dominate the measured current-induced magnetic fields. In our safety study, we show that using low-conductivity leads gets rid of the practical limitations that come with using safety resistors and twisted pair cables while also reducing the chances of adverse heating. Our leads have additionally been proven to be safe for both 3T and 7T MRI, while current commercial systems are only approved for 3T or below.

For the article as a pdf, click HERE.