case_images: PMC10879278_01
case_images: Improved OCD and depression outcomes from tractography-informed DBS repositioning. (A) axial view of the original (light blue) and repositioned DBS leads (dark blue). (B) coronal view of the original (light blue) and repositioned DBS leads (dark blue). (C) clinical improvement in OCD (YBOCS), depression (PHQ-9), and anxiety (GAD7) scores before DBS, after DBS, and following right lead repositioning.
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case_images: fig1
case_images: Two quadripolar DBS leads (3,387; Medtronic, Minneapolis, MN) were stereotactically implanted within the bilateral ventral ALIC, with the middle contacts being targeted close to the bed nucleus of the stria terminalis (BNST). The right lead was positioned approximately 5 mm closer to the midline compared with the left lead position on the MRI (Figures 1A,B). The middle contacts of the right lead were positioned within the BNST. DBS) and improvement in depression (PHQ-9 reduced to 14; 40% improvement) after 1 year of treatment (Figure 1C). During this time, medications were not altered, and the patient was engaged in weekly ERP. The right DBS lead was repositioned so the dorsal contacts were within the ATR based upon the tractography, mirroring the more lateral placement of the left therapeutic lead (Figures 1A,B). His depressive symptoms also improved by 64% (reduction in PHQ-9 to 9) relative to before DBS (Figure 1C). We were able to successfully reconstruct tracts passing through the estimated VAT from the originally positioned right lead, the repositioned right lead, and the left lead, using both the post-implant and post-repositioning DWI with the DBS leads in place (Supp Fig S1).
case_images: Tractography from estimated VAT. Tractography from the estimated VAT from the therapeutic active left contact (5 mA C + 2-) (left panel), right contact (5 mA C + 1-) from the originally positioned right lead (middle panel), and right contact from the repositioned right lead (right panel). Tractography was conducted with the pre-implant DWI.
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case_images: fig2
case_images: T1-weighted structural MRI for lead localization. The left VAT demonstrated structural connectivity to the medial PFC, mediodorsal thalamus, and STN through tracts previously associated with benefit for OCD (Figure 2, left panel). Instead, the right VAT was structurally connected with the stria terminalis and ansa peduncularis, tracts that project to the temporal lobe and amygdala (Figure 2, middle panel). Using the pre-implant DWI, we conducted tractography from the stimulation field corresponding with the repositioned right lead (Figure 2, right panel). These tractography results are consistent with prior studies demonstrating that increased structural connectivity to these regions is correlated with improved DBS outcomes for OCD (Figures 2, 3). There was also decreased connectivity between the VAT and the right temporal lobe following repositioning, which has been associated with worse outcomes (Figures 2, 3). We also validated the tractography from the post-repositioning DWI against the pre-implant and post-implant tractography (Supplementary Figure S2).
case_images: Change in structural connectivity following DBS repositioning. Change in streamline counts between the repositioned and originally positioned active contact on the right leads to different brain regions. Streamlines are derived from tractography using the pre-implant DWI.
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case_images: fig3
case_images: These tractography results are consistent with prior studies demonstrating that increased structural connectivity to these regions is correlated with improved DBS outcomes for OCD (Figures 2, 3). There was also decreased connectivity between the VAT and the right temporal lobe following repositioning, which has been associated with worse outcomes (Figures 2, 3).
case_images: Correlation between tractography results from pre-implant, post-implant, and post-repositioning DWI. (A) Scatterplot of the streamline counts to each parcel for the original lead positioning using pre- and post-implant DWI. (B) bar graph showing the correlation coefficient of the streamline counts between parcellated regions and the VAT corresponding with the originally positioned right lead, repositioned right lead, and left lead comparing the pre-implant and post-implant DWI. *** p < 0.0001 based upon a t-test.
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case_images: PMC10879278_01_fnhum-17-1339340-g004.jpg
case_images: fig4
case_images: We validated the tractography using the post-implant DWI against the pre-implant results, demonstrating a strong correlation between the streamline counts from the VAT to other parcellated brain regions (Figure 4, rR Lead-Original = 0.89; p = 2.4 x 10-39, rR Lead-Repositioned = 0.84; p = 6.7 x 10-31, rL Lead = 0.86; p = 2.6 x 10-34).