Observations from the first 100 cases of intraoperative MRI - experiences, trends and short-term outcomes

Abstract

Background: We sought to analyze, in well-defined clinical setting, the first 100 patients treated at the intraoperative MRI (iMRI) hybrid surgical theatre at our facility in a population-based setting to evaluate which pathologies are best approached with iMRI assisted surgeries, as this is not yet clearly defined.

Methods: Patients undergoing surgery in the 3T iMRI hybrid surgical theatre at our neurosurgical department between December 2017 to May 2021 were included after informed consent. Demographic, clinical, surgical, histological, radiological and outcome parameters, as well as variables related to iMRI, were retrospectively collected and analyzed. Patients were subdivided into adult and pediatric cohorts.

Results: Various neurosurgical procedures were performed; resection of tumors and epileptic foci, endoscopic skull base procedures including pituitary lesions, deep brain stimulation (DBS) and laser interstitial thermal therapy (LITT). In total, 41 patients were pediatric. An iMRI scan was carried out in 96% of cases and led to continuation of surgery in 50% of cases, mainly due to visualized remaining pathological tissue (95.2%). Median time to iMRI from intubation was 280 min and median total duration of surgery was 445 min. The majority of patients experienced no postoperative complications (70%), 13 patients suffered permanent postoperative deficits, predominantly visual.

Conclusion: Herein, we demonstrate the first 100 patients undergoing neurosurgery aided by iMRI at our facility since introduction. Indications for surgery differed between pediatric and adult patients. The iMRI was utilized for tumor surgeries, particularly adult low-grade gliomas and pediatric tumors, as well as for epilepsy surgery and DBS. In this heterogenous population, iMRI led to continuation of surgery in 50%. To establish the benefit in maximizing the extent of resection in these brain pathologies future studies are recommended.

Clinical trial number: Not applicable.

Keywords: Brain tumors; Deep brain stimulation; MRI scan; Neurosurgery.

Fig. 1

iMRI suite set up. Left: Patient model with affixed Mayfield charcoal skull clamp and one 4-channel receiver flex coil (blue) below the head. Right: Intraoperative positioning of sterile dressed patient on the fixed operating table with the second receiver flex coil in blue (black arrow) placed over the patients’ head after temporary closure of surgical wound. The patient head is positioned in the center of the bore during iMRI scanning

Fig. 2

Intraoperative T2-weighted MRI images of a dysembryoplastic neuroepithelial tumor (DNET) in the right frontal lobe before (2 A-B) and after (2 C-D) continued resection following iMRI. Remaining tumorous tissue detected on iMRI before extended resection is demonstrated with white arrows (2 A-B). After resection, achieved GTR is demonstrated with green arrows (2 C-D)

Fig. 3

Sankey plot over performed surgeries and whether surgery was continued or not (n = 96). Patients undergoing endoscopic skull base surgeries with pituitary/skull base lesions who did not perform an intraoperative MRI (4) are excluded in Fig. 3