Introduction: Intra-operative magnetic resonance imaging (iMRI) is a recent adjunct that can be used to identify residual tumor during a surgical procedure. This study’s purposed was to assess accuracy of additional resection for tumor after identification of residual on iMRI.
Methods: Analysis of multicenter REDCapTM mixed retrospective/prospective database of over 5700 patients who underwent resections for brain tumors. iMRI was performed using a movable ceiling-mounted high-field magnet at the surgeon’s discretion Additional resection was pursued if residual tumor was identified on iMRI and surgeon deemed appropriate. Logistic regression and frequency table analyses were performed to calculate odds of additional resection and positive pathology.
Results: Five-thousand-seven-hundred-and-forty-nine brain tumor patients underwent 6599 resections, including 4625 first-time operations for primary tumors. Of all resections, 3236 received iMRI with 1219 (26.3%) additional resections after iMRI. High-grade gliomas (HGGs) were more likely to receive additional resection (454/773, 58.7%; compared to low-grade glioma (LGG): 296/556, 53.2%, p=.05, OR 1.25 [1.00, 1.56]; pituitary adenomas (PA): 169/508, 33.27%, p<.001, OR 2.86 [2.26, 3.61]), and other (158/433, 33.27%, p<.001, OR 2.481 [1.95, 3.15]).
In 477 cases with additional resection after iMRI, independent post-iMRI tumor samples were available, and 413 (86.6%) were positive for tumor (189/207, 91% HGG, referent; 99/116, 85.34% LGG, p=.102; 53/65, 81.54% PA, p=.032; and 65/76, 85.5% other, p=.1597). One-hundred-and twenty-eight-patients received a second iMRI, 11 a third, and 2 a fourth, with 37, 4, and 1 further resections post-iMRI, respectively. All four samples available after two or more iMRI scans were positive. Primary tumors (286/325, 88%) were not more likely to yield positive pathology than recurrent tumors (111/130, 85.38%, p=.45).
Conclusions: High-grade gliomas were more likely to undergo additional resection after iMRI. Additional resection led to positive tumor pathology in 86.6% of iMRI cases indicating that iMRI can accurately identify residual tumor in multiple settings.
Patient Care: By the conclusion of this session, participants should be able to 1) describe the role of iMRI in resection of primary brain tumors, 2) describe basic trends in utilization of iMRI, and 3) discuss the accuracy of additional resection following identification of additional tumor on iMRI scan.
Learning Objectives: By the conclusion of this session, participants should be able to 1) describe the role of iMRI in resection of primary brain tumors, 2) describe basic trends in utilization of iMRI, and 3) discuss the accuracy of additional resection following identification of additional tumor on iMRI scan.