FLGS-02. What is the role of intraoperative MRI when performing a high-grade glioma resection using 5-ALA? A single center series reporting extent of resection of contrast-enhancing tumor and FLAIR signal abnormality with clinical outcomes

Abstract

Abstract OBJECTIVE Use of intraoperative MRI (iMRI) and 5-ALA together is poorly investigated although both appear individually superior to standard resection alone in meta-analyses. METHODS We identified 54 patients who underwent 5-ALA guided resection of an intracranial high-grade glioma. Intraoperative ultrasound and frameless stereotactic neuronavigation with tractography were used in all cases. iMRI was selectively used in 33 cases. MRI scans were used to measure extent of resection (EOR) of T1-weighted contrast enhancing (T1WCE) tumor and FLAIR signal abnormality. Clinical data were collected prospectively and survival data retrospectively. RESULTS The mean EOR of T1WCE tumor was 93.7% (range 38 – 100%) with mean residual volume of 2.2 cc. The mean EOR of FLAIR signal abnormality was 59% (range 15–100%) with mean residual volume of 35.7 cc. Compared to using 5-ALA alone, using iMRI+5-ALA did not reduce the volume of residual T1WCE tumor (Mann-Whitney U, p = 0.557) and no more patients achieved complete resection (14/21 vs. 24/33, Chi-Square, p = 0.634). The volume of residual FLAIR signal abnormality was no different (Mann-Whitney U, p= 0.081) but more patients in the 5-ALA+iMRI group achieved resection of >53.21% of the FLAIR signal abnormality, which is known to be a predictor of improved prognosis (20/31 vs 5/21, Chi-Square, p = 0.004*). There was no difference in new neurological deficits at 30 days (Fisher’s exact test, p=0.549). Median OS was 14.3 months and median PFS was 5.2 months. There were no significant differences in OS or PFS between patients operated with iMRI in addition to 5-ALA. CONCLUSIONS 5-ALA and iMRI both assist in safely maximizing EOR when combined with adjuncts such as awake craniotomy and cortical/subcortical mapping. The role and interaction of these two technologies needs further study to understand whether they are additive and what their influence on clinical outcomes is.