Usefulness of 3T MR in surgical planning for deep brain stimulation surgery: a systematic literature review

Magnetic resonance imaging (MRI) allows direct visualization and targeting of the subthalamic nucleus (STN) and the globus pallidus interna (GPi) during deep brain stimulation (DBS) surgery for Parkinson's disease (PD). Compared to standard 1.5T MRI, the availability of MRI machines with higher magnetic field strength, as 3T MRI, could provide surgical advantages for DBS surgery. The aim of the present systematic review was to gather the available evidence on targeting precision and accuracy, and on clinical outcome, of DBS performed using 1.5T vs. 3T MRI. The literature search yielded 289 results. After duplicate removal and title and abstract screening, 15 full-text papers were assessed, ultimately resulting in the inclusion of six studies in the present work. An improved visualization of STN with 3T MRI was described. Two studies analyzed targeting precision, finding no difference between 1.5T and 3T. Targeting accuracy was evaluated using microelectrode recording-based nucleus identification in four studies: three reported an increased accuracy using 3T MRI, and one reported no differences. Clinical outcome was assessed in three papers, and was judged similar between 1.5T and 3T-based DBS. Risk of bias from the included studies was non-negligible. In conclusion, while the use of 3T MRI can foster deep gray nuclei identification during DBS, according to the available evidence the use of 1.5T MRI remains an adequate option. Further research on this topic is needed. Clinical trial number: Not applicable.