Diagnostic accuracy of intraoperative perfusion-weighted MRI and 5-aminolevulinic acid in relation to contrast-enhanced intraoperative MRI and 11C-methionine positron emission tomography in resection of glioblastoma: a prospective study

The aim of our study was to compare depicted pre-, intra-, and postoperative tumor volume of met-PET, perfusion-weighed MRI (PWI), and Gd-DTPA MRI. Further, to assess their sensitivity and specificity in correlation with histopathological specimen. Inclusion criteria of the prospective study were histological confirmed glioblastoma (GB), age > 18, and eligible for gross total resection (GTR). Met-PET was performed before and after surgery. Gd-DTPA MRI and PWI were performed before, during, and after surgery. A combined 5-aminolevulinic acid (5-ALA) and iMRI-guided surgery was performed. Volumetric analysis was evaluated for all imaging modalities except for 5-ALA. A total of 59 navigated biopsies were taken. Sensitivity and specificity were calculated for Gd-DTPA MRI, PWI, met-PET, and 5-ALA according to the histology of specimen. Met-PET depicted significantly larger tumor volume before surgery (p = 0.01) compared to PWI and Gd-DTPI MRI. We found no significant difference in tumor volume between met-PET and PWI after surgery (p = 0.059). Both PWI and met-PET showed significantly larger tumor volume after surgery when compared to Gd-DTPA (p = 0.018 and p = 0.003, respectively). Intraoperative PWI reading was impaired in 33.3% due to artifacts. Met-PET showed the highest sensitivity for detection of GB with 95%. The lowest sensitivity was found with Gd-DTPA MRI (50%), while 5-ALA and intraoperative PWI showed similar results (69 and 67%). Met-Pet is the imaging modality with the highest sensitivity to detect a residual tumor in GB. Intraoperative PWI seems to have a synergistic effect to Gd-DTPA and 5-ALA. However, its value may be limited by artifacts. Both pre- and intraoperative PWI cannot substitute met-PET in tumor detection.