Introduction:Deep brain stimulation (DBS) is a well-established treatment for movement
disorders. High magnetic fields could have an impact on distortion. We evaluated 1.5-
and 3-T magnetic resonance imaging (MRI) sequences for accuracy, precision, and trueness
of our MRI-guided direct targeting protocol.Methods:Effects of distortion on MR sequences
(T1- and T2-weighted sequences) can be evaluated using a dedicated phantom (Elekta).
Field strength capabilities were assessed on Siemens Avanto (1.5 T) and Skyra (3 T)
scanners. We assessed the precision of our stereotactic MRI-guided procedure.Results:We
focused on the risk of error due to a high field strength. Error values on the localizer
box were between 0.4 and 0.7 mm at 1.5 T and between 0.6 and 2 mm at 3 T. The most
accurate 1.5-T sequence is the 3D FLASH T1-weighted sequence, which had an accuracy
value of 0.6 mm. At 3 T, the accuracy value of the isotropic 3D FLASH T1-weighted
sequence was 1.6 mm.Conclusion:Given the millimetric size of stereotactic targets
and electrodes, lead implantation for neuromodulation therapy needs to be accurate.
We demonstrate that 3-T imaging could not be used for stereotaxy in our MRI-guided
direct targeting protocol because of a risk of error induced by distortion.