Objective: To report our experience with the use of high-field IoMRI (1.5 T) for both enhancing and non-enhancing gliomas.
Methods: An IRB-approved retrospective review was performed on 102 consecutive glioma patients (104 surgeries, 2010-12). Pre-, intra-, and post-operative tumor volumes were assessed. Analysis was performed with use of volumetric T2 images in 43 non-enhancing and 13 minimally-enhancing tumors, and with post-contrast volumetric MPRAGE images in 48 enhancing tumors.
Results: In 58 cases, pre-operative imaging showed tumors likely to be amenable to a complete resection. Intra-operative electrocorticography (ECoG) was performed in 32 surgeries and 14 cases resulted in intended subtotal resection of tumors due to involvement of deep functional structures. 25 surgeries required no further resection (complete resection prior to IoMRI), and IoMRI showed residual tumor in 79 cases. Of these, 25 surgeries did not proceed to further resection: 9 due to ECoG findings, 14 due to tumor in deep functional areas, and 2 due to surgeon choice. Additional resection that was performed in 54 cases resulted in a final median residual tumor volume of 0.21cc (0.6%). In 79 cases that were amenable to complete resection, intra-operative median residual tumor volume for the T2 group was higher than for the MPRAGE group (1.088cc versus 0.437cc; p=0.049), while post-operative median residual tumor volume was not statistically significantly different between groups.
Conclusion: IoMRI enhances extent of resection, particularly for non-enhancing gliomas.
From: Use of High-Field Intra-Operative Magnetic Resonance Imaging to Enhance the Extent of Resection of Enhancing and Non-Enhancing Gliomas by Mohammadi et al.