Gross-total surgery of supratentorial low-grade gliomas under intraoperative MR guidance

BACKGROUND AND PURPOSE: Length of survival of patients with low-grade gliom a correlates with the extent of tumor resection. These tumors, however, are difficult to distinguish intraoperatively from normal brain tissue, often leading to incomplete resection. Our goal was to evaluate the effectiveness of intraoperative MR guidance in achieving gross-total resection. METHODS: We studied 12 patients with low-grade glioma who underwent surgery within a vertically open 0.5-T MR system. During surgery, localization of residual tumor tissue was guided by interactive, near real-time imaging. Th e amount of residual tumor tissue on MR images was evaluated at the point o f the operation at which the neurosurgeon would have terminated the procedu re under conventional conditions (first control) and again before closing t he craniotomy. RESULTS: Significant residual tumor (more than 10% of original tumor volume ) was shown in eight patients at the first control condition. The percentag e of resection varied from 26% to 100% (mean, 68%) at this time. Twelve tis sue samples from seven patients were obtained in areas identified as residu al tumor on MR images. In 10 cases, the neuropathologic investigation confi rmed the presence of residual low-grade glioma; in two cases, the borderzon e of tumor was identified. In evaluating the final sets of images, we found total resection in six cases, over 90% resection in five cases, and 85% re section in one case (mean, 96%). CONCLUSION: Surgical treatment of low-grade gliomas under intraoperative MR guidance provides improved resection results with maximal patient safety.