Intraoperative MR imaging increases the extent of tumor resection in patients with high-grade gliomas

BACKGROUND AND PURPOSE: MR is being used increasingly as an intraoperative imaging technique, The purpose of this study was to test the hypothesis tha t intraoperative MR imaging increases the extent of tumor resection, thus i mproving surgical results in patients with high-grade gliomas, METHODS: Thirty-eight patients with intracranial high-grade gliomas underwe nt 41 operations. Using a neuronavigation system, tumors were resected in a ll patients to the point at which the neurosurgeon would have terminated th e operation because he thought that all enhancing tumor had been removed. I ntraoperative MR imaging (0.2 T) was performed, and surgery, if necessary a nd feasible, was continued. All patients underwent early postoperative MR i maging (1.5 T), By comparing the proportions of patients in whom complete r esection of all enhancing tumor was shown by intraoperative and early posto perative MR imaging, respectively the impact of intraoperative MR imaging o n surgery was determined, RESULTS: Intraoperative MR imaging showed residual enhancing tumor in 22 ca ses (53.7%), In 15 patients (36.6%), no residual tumor was seen, whereas th e results of the remaining four intraoperative MR examinations (9.7%) were inconclusive, In 17 of the 22 cases in which residual tumor was seen, surge ry was continued. Early postoperative MR imaging showed residual tumor in e ight patients (19.5%) and no residual tumor in 31 cases (75.6%); findings w ere uncertain in two patients (4.9%), The difference in the proportion of " complete removals" was statistically highly significant (P=.0004), CONCLUSION: Intraoperative MR imaging significantly increases the sate of c omplete tumor removal. The rate of complete removal of all enhancing tumor parts was only 36.6% when neuronavigation alone was used, which suggests th e benefits of intraoperative imaging.