Impact of the Combination of 5-Aminolevulinic Acid-Induced Fluorescence with Intraoperative Magnetic Resonance Imaging-Guided Surgery for Glioma

OBJECTIVE: To compare intraoperative magnetic resonance imaging (MRI)-guided resection with resection guided by 5-aminolevulinic acid (5-ALA)-induced fluorescence in patients with gliomas and to evaluate the impact of intraoperative MRI in glioma surgery. METHODS: From January 2005 to February 2009, 33 patients with gliomas (6 with World Health Organization [WHO] grade II, 7 with WHO grade III, 20 with WHO grade IV) who underwent craniotomy with neuronavigation and received 5-ALA by the same neurosurgeon were investigated retrospectively. In 19 patients, operations were performed using a combination of 5-ALA with intraoperative 1.5-T MRI. All patients were subjected to postoperative 1.5-T MRI to confirm the extent of resection. RESULTS: Of 33 patients with gliomas, 21 (4 with WHO grade III and 17 with WHO grade IV) were 5-ALA-induced fluorescence-positive (5-ALA (+)). Surgery with intraoperative MRI was performed in 10 of the 21 patients, and the average resection rate was 92.6%. The average resection rate of patients who underwent surgery without intraoperative MRI was 91.8%. 5-ALA-induced fluorescence was not detected in 12 patients (6 with WHO grade II, 3 with WHO grade III, and 3 with WHO grade IV) with gliomas. Surgery with intraoperative MRI was performed in 9 of 12 patients, and the average resection rate was 89.2%. The average resection rate of patients who underwent surgery without intraoperative MRI was 68.7%. Intraoperative MRI-guided tumor resection resulted in a better resection rate in patients with 5-ALA-induced fluorescence-negative (5-ALA (-)) gliomas than in patients with 5-ALA (+) gliomas (20.5% vs 0.8%). CONCLUSIONS: Intraoperative MRI-guided resection is a powerful tool to treat 5-ALA (-) gliomas (mostly low grade), and 5-ALA is useful for high-grade gliomas. The combination of intraoperative MRI and 5-ALA has a synergistic effect in glioma surgery. Additionally, precise tumor grading in preoperative imaging studies can be difficult. Surgery for gliomas should be performed using both 5-ALA-induced fluorescence and intraoperative MRI-guided resection.