Computer-Assisted Stereo-Electroencephalography Planning: Centre-Specific Priors Enhance Planning

Abstract

Objectives
To refine computer-assisted planning (CAP) of SEEG implantations by adding constraints of prior spatial SEEG trajectories (‘Priors’) to improve safety, reduce manual adjustments required, without increasing planning time.

Methods
Retrospective validation based on 159 previously implanted trajectories (11 cases) planned by the clinical standard CAP, and CAP constrained with spatial priors (“CAP+Priors”). Constraints comprise 31 target and 51 entry zones, created from 98 consecutive patients (763 implanted SEEG trajectories). Each of 159 previously implanted trajectories were planned by two fellows, once with CAP, and once with CAP+Priors, in a randomized order. Times taken to generate the initial computer-generated plan (T1) and the user-edited final plan (T2) were recorded, together with the proportions of electrodes that required subsequent adjustments. Clinical implantability was assessed via blinded review of each trajectory by five independent epilepsy neurosurgeons with expertise in SEEG implantation.

Results
Expert raters considered 88.5% of trajectories implantable, with no difference in acceptability between CAP alone & CAP+Priors (p=.79). Median (IQR) T1 for CAP to produce a full automated implantation was 4.6 (0.85) minutes, vs CAP+Priors was 6.3 (2.6) minutes (p=.03). There was no significant difference in T2 (time to complete surgeon-edited plan): CAP median (IQR) 105 (22)minutes, CAP+Priors 96 (68)minutes (p=.92). CAP+Priors risk score was significantly lower than that for the previously actually implanted trajectories for the 11 plans analyzed (p=.004), and no different to CAP alone planning. There was a significant reduction in manual adjustments required with CAP+Priors in the cingulate gyrus.

Conclusions
The use of spatial priors from previous implantations enhances SEEG CAP and increases the granularity of trajectory planning. This technique facilitates standardization of planning and allows for the incorporation of experience from multiple expert centers, decreasing risk of the resultant trajectories, reducing the proportion of trajectories that require manual planning, without significantly increasing planning time.