Combined Brain Mapping and Compact Intraoperative MRI for Brain Tumor Resection

Surgery on patients with lesions in the dominant hemisphere for language is best done with awake language mapping. Intraoperative MRI (iMRI) has also been proposed as an ideal method for tumor resection control in patients with primary brain tumors.

This study examines the feasibility of low-field iMRI during awake craniotomy and tumor resection.

36 patients underwent awake resection with a compact iMRI for guidance. Outcomes were grouped using an A-D classification. Outcome A was defined as gross total resection (GTR) without iMRI, B as GTR achieved secondary to iMRI findings, C as resection stopped due to mapping but prior to iMRI, and, finally, D as resection stopped after iMRI had showed residual tumor but subsequent mapping limited further resection.

Diagnoses included primary brain tumors in all but 2 patients: 1 had mesial temporal sclerosis and 1 cysticercosis. Overall, outcomes A and D were the most common with 12 patients each, outcome C was the least common occurring in only 3 patients, and outcome B occurred in 9 patients. Hence, in 12 patients, iMRI led to increased tumor resection while in another 12 brain mapping limited the extent of resection.

Combined awake language and motor mapping and iMRI guidance is feasible for resection of brain lesions. A compact iMRI has unique advantages for this approach.