Endogenous chemical exchange saturation transfer (CEST) MR imaging for the diagnosis and therapy response assessment of brain tumors: A systematic review

Abstract

Purpose: To generate a narrative synthesis of published data on the use of endogenous chemical exchange saturation transfer (CEST) MR imaging in brain tumors. Materials and Methods: A systematic database search (PubMed, Ovid Embase, Cochrane Library) was used to collate eligible studies. Two researchers independently screened publications according to predefined exclusion and inclusion criteria, followed by comprehensive data extraction. All included studies were subjected to a bias risk assessment using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Results: The electronic database search identified 430 studies, of which 36 studies fulfilled the inclusion criteria. The final selection of included studies was categorized into 5 groups as follows: grading gliomas, 19 studies (areas under the curve (AUC) 0.500-1.000); predicting molecular subtypes of gliomas, 5 studies (AUC 0.610-0.920); distinction of different brain tumor types, 7 studies (AUC 0.707-0.905); therapy response assessment, 3 studies (AUC not given) and differentiating recurrence from treatment-related changes, 5 studies (AUC 0.880- 0.980). A high bias risk was observed in a substantial proportion of studies. Conclusion: Endogenous CEST imaging offers valuable, potentially unique information in brain tumors, but its diagnostic accuracy remains incompletely known. Further research is required to assess the method’s role in support of molecular genetic diagnosis, to investigate its use in the post treatment phase, and to compare techniques with a view to standardization