The Role of Intraoperative MRI in Resection of High-Grade Glioma Using 5-ALA: A Single-Center Case Series

Abstract

BACKGROUND AND OBJECTIVES: Outcomes in high-grade glioma (HGG) remain poor despite maximal safe tumor resection. Although intraoperative MRI (iMRI) or 5-aminolevulinic acid (5-ALA) individually has demonstrated clinical benefit, their combined use has not been evaluated extensively. We sought to evaluate the benefit of combined use of iMRI and 5-ALA in patients with HGG who underwent craniotomy and tumor resection. METHODS: We identified 54 patients who underwent 5-ALA–guided resection of intracranial HGG. iMRI was used in 33 cases. Intraoperative ultrasound and frameless neuronavigation with tractography were used for all cases. Using standard MRI sequences, the extent of resection (EOR) of T1-weighted contrast-enhancing (T1WCE) tumor and fluid-attenuated inversion-recovery (FLAIR) signal tumor were calculated. RESULTS: There were no significant differences in EOR of T1WCE tumor, volume of residual T1WCE tumor, and volume of residual FLAIR signal abnormality between the 5-ALA and iMRI + 5-ALA groups. Although the number of patients with complete resection did not differ significantly, more patients in the iMRI + 5-ALA group achieved resection of >53.21% of the FLAIR signal abnormality (20/31 vs 5/21, Pearson χ2, P = .004), which is known to be a predictor of improved prognosis. No significant differences in overall survival or progression-free survival between the groups and no association between EOR and clinical outcomes were observed, which may be due to the size of this study. There was no difference in new neurological deficit between the groups at 30 days after surgery. CONCLUSION: Surgery with 5-ALA alone is as effective as surgery with 5-ALA and iMRI at achieving maximal safe resection, when combined with adjuncts. Our findings suggest that the role and interaction of these technologies needs to be further studied in larger, prospective studies to understand whether their utility is complementary or additive, particularly their influence on EOR of FLAIR signal abnormality and subsequent clinical outcomes.