A three-dimensional conformal radiofrequency thermocoagulation method for epileptogenic zones in functional cerebral areas: evaluation and prediction of surgical outcomes

Fig. 1. Representative images of electrode implantation designed with image reconstruction (Patient 6). a–c Preoperative MRI FLAIR images in the axial, sagittal and coronal plane with the FCD in the left precentral gyrus. d Fused image of MRI FLAIR and PET with the FCD. e Segmentation of gray matters based on MRI T1 images with the FCD. f–g Reconstruction model of the cerebral surface (gray), vessels (red), electrodes (red lines, with corresponding letters of electrodes), FCD structure (yellow) and corticospinal tract (blue lines), with the personalized SEEG electrode-implantation trajectories based on the models. Crossing point of yellow lines in (a–e) is the location of the FCD in the left precentral gyrus. Abbreviation: SEEG, stereo-electroencephalography; FCD, focal cortical dysplasia

Fig. 2. Preoperative SEEG for EZ identification (Patient 6). a SEEG signals of identified seizure onset zones in the preictal and ictal period. b Spatial relationship between electrode contacts of seizure onset (green dots and corresponding letters of contacts) and the model of FCD (yellow) and corticospinal tracts (blue lines). Abbreviation: SEEG, stereo-electroencephalography; EZ, epileptogenic zones; FCD, focal cortical dysplasia

Fig. 3. Preoperative and postoperative image evaluation (Patient 1). a–c Preoperative MRI T1 images showing the location of thermo-lesions in the right paracentral lobule in the axial, coronal and sagittal plane fused with the corticospinal tract of the lower limb. d Lateral view of spatial relationship between electrodes and the three-dimensional cerebral model. e Medial view of spatial relationship between the targets of electrodes and the three-dimensional cerebral model, with cortical parcellation marked by different colors. f Spatial relationship between trajectories of electrodes and right corticospinal tract of the lower limb. g–i Postoperative MRI T1 showing the range of thermo-lesions in the axial, coronal and sagittal plane fused with the right corticospinal tract of the lower limb. Blue streamlines in (a–c) and (g–i), and blue lines in (d–f) are the right corticospinal tract of the lower limb. Crossing point of yellow lines in (a–c) and (g–i) is the location of thermo-lesions. Orange lines in (d–f) present electrodes with their corresponding letters

Fig. 4. Statistical analysis of LL and ApEn. a LL and ApEn between the RF-TC contacts and the other contacts in the preoperative interictal period. b LL and ApEn between preoperative and postoperative contacts without RF-TC. For all notched boxplots, the central mark of the box indicates the median, and the bottom and top edges of the box indicate the 25th and 75th percentiles, respectively. The notches represent the confidence interval around the median. The lower and upper whiskers describe the rest of the distribution. Individual points beyond the whiskers of the boxplot are marked as outliers. Asterisks represent two-tailed significant p-values with Bonferroni’s correction (*, 0.01 ≤ P < 0.05; **, 0.001 ≤ P < 0.01; ***, P < 0.001). Abbreviation: LL, line length; ApEn, approximate entropy; RF-TC, radiofrequency thermocoagulation; TC, biomarkers from RF-TC contacts; nTC-pre, preoperative biomarkers from contacts without RF-TC; nTC-post, postoperative biomarkers from contacts without RF-TC