Performance of ¹⁸F-fluoro-ethyl-tyrosine ( ¹⁸F-FET) PET for the differential diagnosis of primary brain tumor: A systematic review and metaanalysis

For the past decade, PET with ¹⁸F-fluoro-ethyl-tyrosine ( ¹⁸F-FET) has been used in the evaluation of patients with primary brain tumors (PBTs), but so far series have reported only a limited number of patients. The purpose of this systematic review and metaanalysis was to assess the diagnostic performance of ¹⁸F-FET PET in patients with suspicion of PBT. Methods: We examined studies published in the literature using MEDLINE and EMBASE databases. Inclusion criteria were use of ¹⁸F-FET PET for initial assessment of patients with a newly diagnosed brain lesion; patients who had no radiotherapy, surgery, or chemotherapy before ¹⁸F-FET PET; and use of histology as a gold standard. Metaanalysis was performed on a per-patient basis. We secondarily performed receiver-operating-characteristic analysis of pooled patients to determine tumor-to-background ratio (TBR) of ¹⁸F-FET uptake and best diagnostic value. Results: Thirteen studies totaling 462 patients were included. For the diagnosis of PBT, ¹⁸F-FET PET demonstrated a pooled sensitivity of 0.82 (95% confidence interval [CI], 0.74-0.88), specificity of 0.76 (95% CI, 0.44-0.92), area under the curve of 0.84 (95% CI, 0.80-0.87), positive likelihood ratio of 3.4 (95% CI, 1.2-9.5), and negative likelihood ratio of 0.24 (95% CI, 0.14-0.39). Receiver-operating-characteristic analysis indicated that a mean TBR threshold of at least 1.6 and a maximum TBR of at least 2.1 had the best diagnostic value for differentiating PBTs from nontumoral lesions. Conclusion: ¹⁸F-FET PET demonstrated excellent performance for diagnosing PBTs. Strict standardization of PET acquisition protocols and prospective, multicenter studies investigating the added value over current MRI are now needed to establish ¹⁸F-FET PET as a highly relevant tool for patient management.