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

Abstract

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.

Comparison of Amino Acid PET to Advanced and Emerging MRI Techniques for Neurooncology Imaging: A Systematic Review of the Recent Studies

“…The authors concluded that these modalities provide different information; however, they did not study the performance of these imaging modalities combined [ 56 ]. In another study of 18 GBMs, Pala et al obtained MET PET and PWI scans asynchronously before, during (MRI only), and after surgery in order to compare tumor volume and diagnostic accuracy compared to histopathology [ 57 ]. Similar to Beppu et al, they found that before gross total resection, MET PET yielded a larger tumor volume than PWI, a difference that disappeared after surgery.…”

“…MET PET demonstrated higher sensitivity for GBM detection (95%) than PWI (67%). The authors did not explore the question of combining modalities [ 57 ].…”

5-ALA in Suspected Low-Grade Gliomas: Current Role, Limitations, and New Approaches

“…In the literature, different studies also correlated PET imaging with visible 5-ALA fluorescence in diffusely infiltrating gliomas (36,92,(95)(96)(97)(98). In this sense, Stockhammer et al first reported in 2009 that the standardized uptake value of PET related to normal brain using 18 F-fluoroethyl-L-tyrosine (FET) was significantly higher in tumor areas with 5-ALA fluorescence as compared to normal brain with absence of visible fluorescence (95).…”

State-of-the-art imaging for glioma surgery

“…Multiple studies compared 5-ALA with amino acid PET and iMRI for the detection of tumor tissue. All but one of the PET studies found a higher sensitivity for PET [ 20 , 65 ] or residual post-operative tracer uptake after complete resection of 5-ALA [ 42 , 59 ]. It has to be mentioned that these were all retrospective studies with different thresholds or qualitative interpretation of tracer uptake.…”