Diffusion tensor imaging to aid subgenual cingulum target selection for deep brain stimulation in depression.

ABSTRACT

BACKGROUND: The most investigated target for deep brain stimulation in depression is the subgenual cingulate gyrus (Cg25) which has been shown to be a critical hub for signalling in the condition. Diffusion tensor imaging (DTI) is a form of MR sequence that can visualise white matter connections and potentially aid target selection. OBJECTIVES: To assess whether targets selected using DTI to find the area of maximal tract crossover (maximal isotropy) underlying the subgenual cingulum differ significantly in location from those selected using standard T(2) sequences. METHODS: Fifty-nine non-depressed adult volunteers underwent MR imaging using T(1), T(2) and DTI sequences of the brain. Each patient had targets selected for both hemispheres using both T(2) and DTI sequences. The significance of the differences in coordinates in all three dimensions was tested using the paired t test. RESULTS: There was a significant difference in the mediolateral (x) and dorsoventral (z) coordinates of DTI targets when compared with T(2) targets (p < 0.001). CONCLUSIONS: Targets within Cg25 selected using DTI are significantly different in location from those selected using T(2) sequences and have the potential to enhance treatment outcome by reducing the impact of interindividual variability.