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. 2022 Jan 13;8:824003. doi: 10.3389/fsurg.2021.824003

Figure 1.

Figure 1

(A) Patient 1. Upper: Preoperative axial FLAIR (left) and coronal T2-weighted MRI (right) revealing a left posterosuperior insular LGG in a 35-year-old man who experienced seizures. Middle: Intraoperative view (the anterior part of the left hemisphere is on the right and its posterior part is on the left) after resection in awake patient, achieved up to eloquent structures, both at cortical and subcortical levels. Number tags show positive DES sites, i.e., primary motor cortex of the face (4), ventral premotor cortex eliciting anarthria when stimulated (3, 5), and primary somatosensory cortex of the face (6–8) within the lateral part of the retrocentral gyrus (rolandic operculum). According to this cortical mapping, a transopercular surgical approach has been selected via the alSMG (through the parietal operculum). In addition to the functional cortical areas, DES of white matter tracts allowed the detection of the critical subcortical neural networks (lSLF and AF). Lower: Postoperative axial FLAIR (left) and coronal T2 (right) MRI 3 months following surgery demonstrating NTR. The neurological examination was normal 3 months following surgery, after transitory phonological disorders. The diffuse WHO grade II oligodendroglioma was diagnosed, and no adjuvant treatment was administrated, with a regular surveillance. (B) Patient 2. Upper: Preoperative axial FLAIR (left), coronal FLAIR (middle), and sagittal FLAIR-weighted MRI (right) revealing a left posterosuperior insular LGG in a 59-year-old man who experienced seizures. Middle: Intraoperative view (the anterior part of the left hemisphere is on the right and its posterior part is on the left) after resection in awake patient, achieved up to eloquent structures, both at cortical and subcortical levels. Number tags show positive DES sites, i.e., primary motor cortex of the face (4), ventral premotor cortex eliciting anarthria when stimulated (1, 3), and primary somatosensory cortex of the face (5) within the retrocentral gyrus. According to this cortical mapping, a transopercular surgical approach has been selected via the lateral part of the retrocentral gyrus (through the posterior rolandic operculum). In addition to the functional cortical areas, DES of white matter tracts allowed the detection of the critical subcortical neural networks (lSLF, AF, IFOF, and somatosensory TCP). Lower: Postoperative axial FLAIR (left), coronal FLAIR (middle), and sagittal FLAIR-weighted MRI (right) demonstrating GTR. The neurological examination was normal 3 months following surgery. The diffuse WHO grade II astrocytoma was diagnosed, and no adjuvant treatment was administrated, with a regular surveillance. LGG, low-grade glioma; DES, direct electrical stimulation; alSMG, anterolateral part of the supramarginal gyrus; lSLF, lateral part of the superior longitudinal fasciculus (red circle); AF, arcuate fasciculus (yellow circle); IFOF, inferior fronto-occipital fasciculus (green circle); TCP, thalamocortical pathway (blue circle); GTR, gross total resection; NTR, near total resection.