The impact of intra-operative high field magnetic resonance imaging on clinical decision making during oncologic neurosurgical procedures
19599 Background: Existing image guided surgical (IGS) technology used during resection of brain tumors is based on preoperative imaging modalities and are limited by their inability to demonstrate extent of resection (EOR) and compensate for anatomical changes which occur as a result of surgical manipulation (e.g. brain shift, tumor resection, spinal fluid loss). Having the ability to perform MRI during brain tumor surgery obviates many of these limitations. The purpose of this study was to determine the impact of intra-operative imaging with a high field MRI on brain tumor resection. Methods: Since September 2006, a total of 23 patients with brain tumors underwent resection at The University of Texas M. D. Anderson Cancer Center with intra-operative MR guidance (BrainLAB IGS system integrated with a 1.5T Siemens Espree scanner). For each patient, appropriate imaging was performed prior to craniotomy. Resection was then performed using image guidance. Surgeons completed a questionnaire documenting the reason for the scan and provided an estimation of EOR prior to and after the intraoperative scan. Multiple intraoperative scans were performed at the discretion of the operating surgeon. Results: In 23 patients, 25 scans were performed. The patients had a diagnosis of glioma (21), lymphoma (1), and schwannoma (1). Reasons for performing a scan included: evaluate EOR in 23 (92%) or update the IGS system in 2 (8%). Surgeons indicated in 21/23 (91%) scans performed to evaluate the extent of resection that they would have terminated the surgery prior to the scan. In 9/21 cases (43%), further surgery was performed after the scan to maximize EOR. In 10/24 (42%) cases, the pre-scan estimate of residual tumor matched the post-scan amount. The amount of residual tumor was correctly assessed (within 10%) prior to review of the MRI in 19/24 cases. The correlation between the pre-scan estimation of residual tumor and actual post-scan tumor was high (correlation coefficient 0.81, p<0.05). Conclusions: High field intra- operative MRI with high spatial resolution is a useful adjunct to a neurosurgical oncology practice and alters surgical decision making in a significant number of cases. [Table: see text]