**5. Other neurosurgical procedures**

Epilepsy surgery has evolved over the past few decades. ioMRIisalso a valuable tool to achieve complete resection of abnormal areas especially those with lesions. Nilesh S. Kurwale et al. [31] studied on role of ioMRI in achieving seizure control in 39 pharmacoresistant epilepsy patients. This study included tumor (31%), focal cortical dysplasia (28%), mesial temporal lobe surgeries (18%), and disconnectionsurgeries (23%). In lesionalgroupioMRI helped infurtherresections about 21% (5/23) patients. Complete resection was achieved in 87% of patients. ioMRI increases the extent of resection especially in lesionalepilepsy surgeries and thereby good seizure outcomes. Kaibara et al. [32] reported about50% patients had residual hippocampus in ioMRI aiding further resection resulting in 93% seizure freedom

#### *Intraoperative MRI in Brain Tumor Surgeries DOI: http://dx.doi.org/10.5772/intechopen.95588*

at 17 months. Michael Buchfelderet al. [33] assessed 61 patients with pharmacoresistant epilepsy. In this study 32 nonlesional cases underwent surgery using ioMRI, the extent of the tailored 28 temporal resection and 4 callosotomy was well documented. Out of 29 lesional cases the complete resection was done in 23 patients. In three patients lesion was extending into eloquent areas and further resection was not done. In other 3 patients ioMRI enabled to achieve complete resection. ioMRI evaluates the extent of resection or disconnection in epilepsy surgery.

ioMRI during DBS surgery provides real time confirmation of lead placement and other complications. Commonly the microelectrode placement in DBS is done with intraoperative microelectrode recording (MER) in awake conditions. With evolution of ioMRI now a days DBS is being done with ioMRI alone or along with MER. Zhiqiang Cui et al. [34] have done microelectrode placement for movement disorder patients under local anesthesia with MER and ioMRI. 56 (27%) of 206 DBS electrodes were adjusted after initial ioMRI. Another 6 times repositioned after 2 and 3 ioMRI in the same sitting. ioMRI revealed intraparenchymal hemorrhages in 2 patients. Martin Jakobs et al. [35] performed 86 surgeries in 81 patients with Parkinson's disease, essential tremor and dystonia with intraoperative stereotactic MRI-only DBS electrode implantation. A total of 167 electrodes were implanted. In 96.5% of cases the surgeries could be finished as planned. Both length of surgery and the time spent in the stereotactic frame could be significantly reduced. Caio M. Matias et al. [34, 36] evaluated placement accuracy and clinical outcomes in patients with frame-based stereotaxy and ioMRI without MER after induction under general anesthesia in DBS patients. 33 patients underwent implantation, 64 leads in total. MR images were acquired immediately after the procedure and fused to the preoperative plan to verify accuracy. At the last follow-up there was significant improvement (p < 0.001) in symptoms compared to preoperative state. Placement of microelectrodes in DBS with ioMRI reduces the operative time as well as the time in frame. Microelectrode tip location can be confirmed and also any intraoperative complications can be diagnosed. ioMRI is not affected by brain shift due to csf leak or intracranial air, but one has to be aware of the artifacts created by these electrodes. Role ioMRI in DBS is certainly promising and needs further validation in future.
