gms | German Medical Science

Objective: Insular gliomas were considered a long time as inoperable, because of high morbidity rates. The reasons for these are adjacent eloquent cortices and white matter tracts as well as the branching middle cerebral artery. FMRI and DTI were used to receive information about these eloquent areas.

Methods: Preoperative functional imaging with fMRI was performed in 9 patients with insular tumors. For fMRI we used a 1.5T MR scanner with echo planar imaging (Sonata, Siemens Medical Solutions) and a block paradigm with 180 measurements in 6 blocks (rest alternating with activation, 25 slices, 3mm thickness & resolution TR=2470, TE=60). During the activation intervals patients had to perform language tasks, presented visually. Correlation maps were calculated and merged with 3D-MR maps. DTI was used with 1.9 mm slices and 6 directions to reconstruct fibre connections of language areas and the pyramidal tract. Repeated language- and calculation tests were conducted pre- and postoperatively to rate the recovery of neurological function. Intraoperative MRI was used and registered to the functional images to show the extent of resection, the brain shift and an update of the relation to functional structures.

Results: Of the 9 patients 7 had surgery in the left and 2 in the right insula. One of the 7 with surgery in the left insula was right dominant. For all 6 left dominant patients language areas at the cranial border of the insula and in the frontal operculum of the inferior frontal gyrus were obtained. None of the 9 patients had a permanent neurologic deficit.3 patients had transitory language problems, which resolved during 2 weeks. No paresis was observed in any patient.

Conclusion: Functional MRI and DTI Fiber tracking together with functional neuronavigation are able to avoid permanent neurologic deficits like aphasia and paresis while maximizing the extant of resection.