Towards mid-field fMRI of DBS patients: Characterising electrode artefact using multi-echo GRE.

Motivation: MRI imaging for DBS patients is crucial for verifying electrode placement, with fMRI offering insights into the effects on cognitive networks. However, standard T2* imaging at clinical field strengths is hindered by artefacts near implants. Goal(s): This study aims to characterize signal decay and artefact size near DBS electrodes at mid-field MRI strength (0.5 T) to improve T2* protocols for DBS patients. Approach: Using a custom head phantom with DBS electrodes inserted, multi-echo gradient-echo data were acquired and analyzed for artefact volume and width. Results: Reduced artefact size and volume around DBS electrodes at 0.5T, showing potential for future BOLD contrast studies. Impact: 0.5 T reduces artefacts near DBS electrodes, enabling imaging with enhanced safety. This supports better fMRI applications for DBS patients, facilitating improved acquisition methods that can lead towards evaluating DBS effects on cognitive networks and treatment efficacy.