Head-To-Head Comparison of PET and Perfusion Weighted MRI Techniques to Distinguish Treatment Related Abnormalities from Tumor Progression in Glioma

SIMPLE SUMMARY: This meta-analysis provides a first head-to-head comparison of PET and perfusion weighted magnetic resonance imaging (PWI) in the surveillance of post-treatment gliomas in order to distinguish tumor progression (TP) from treatment-related abnormalities (TRA). Although various reviews have been published on the use of either PET or PWI in this setting, no meta-analysis to date provides a head-to-head comparison of both techniques. The findings of this paper illuminate the strengths and limitations of each technique and enable clinicians to take more evidence-based decisions in their daily practice with regard to the imaging surveillance of gliomas. ABSTRACT: The post-treatment imaging surveillance of gliomas is challenged by distinguishing tumor progression (TP) from treatment-related abnormalities (TRA). Sophisticated imaging techniques, such as perfusion-weighted magnetic resonance imaging (MRI PWI) and positron-emission tomography (PET) with a variety of radiotracers, have been suggested as being more reliable than standard imaging for distinguishing TP from TRA. However, it remains unclear if any technique holds diagnostic superiority. This meta-analysis provides a head-to-head comparison of the diagnostic accuracy of the aforementioned imaging techniques. Systematic literature searches on the use of PWI and PET imaging techniques were carried out in PubMed, Embase, the Cochrane Library, ClinicalTrials.gov and the reference lists of relevant papers. After the extraction of data on imaging technique specifications and diagnostic accuracy, a meta-analysis was carried out. The quality of the included papers was assessed using the QUADAS-2 checklist. Nineteen articles, totaling 697 treated patients with glioma (431 males; mean age ± standard deviation 50.5 ± 5.1 years) were included. The investigated PWI techniques included dynamic susceptibility contrast (DSC), dynamic contrast enhancement (DCE) and arterial spin labeling (ASL). The PET-tracers studied concerned [S-methyl-(11)C]methionine, 2-deoxy-2-[(18)F]fluoro-D-glucose ([(18)F]FDG), O-(2-[(18)F]fluoroethyl)-L-tyrosine ([(18)F]FET) and 6-[(18)F]-fluoro-3,4-dihydroxy-L-phenylalanine ([(18)F]FDOPA). The meta-analysis of all data showed no diagnostic superior imaging technique. The included literature showed a low risk of bias. As no technique was found to be diagnostically superior, the local level of expertise is hypothesized to be the most important factor for diagnostically accurate results in post-treatment glioma patients regarding the distinction of TRA from TP.