Diagnosis of pseudoprogression following lomustine-temozolomide chemoradiation in newly diagnosed glioblastoma patients using FET PET

Metabolic and physiologic magnetic resonance imaging in distinguishing true progression from pseudoprogression in patients with glioblastoma

“…Some other studies 46,47 have also shown the potential of [ 18 F]-FET-PET imaging in distinguishing TP from PsP in GBMs (Table 1). The plausible explanation might be that active tumor cells express higher concentrations of mobile protein and peptide components, 122 providing a higher contrast in TP than in PsP.…”

“…Using [ 18 F]‐FET as a PET imaging tracer, Kebir and his colleagues 45 were successful in distinguishing TP (n = 19) from PsP (n = 7) in GBM patients treated with CCRT. Some other studies 46,47 have also shown the potential of [ 18 F]‐FET‐PET imaging in distinguishing TP from PsP in GBMs (Table 1). The plausible explanation might be that active tumor cells express higher concentrations of mobile protein and peptide components, 122 providing a higher contrast in TP than in PsP.…”

Clinical applications and prospects of PET imaging in patients with IDH-mutant gliomas

“…The differentiation of treatment-related changes such as pseudoprogression or radiation necrosis from tumor progression is of utmost importance in clinical routine. Especially amino acid PET using FET [57][58][59][60][61][62][63][64][65] or FDOPA [66][67][68] achieved a high diagnostic accuracy for differentiating treatment-related changes from tumor progression in glioma patients Fig. 2.…”

Facts and Fictions About [18F]FDG versus Other Tracers in Managing Patients with Brain Tumors

“…36 The accuracy of [ 18 F]FET PET scanning in differentiating recurrent WHO grade 4 gliomas from post-treatment changes is high, with sensitivities ranging from 82% to 100% and specificities from 86% to 94%. [95][96][97][98][99] In a recent study including patients with WHO grade 4 gliomas treated with lomustine-temozolomide chemoradiation and for which MRI was equivocal after radiotherapy inside the radiation field (median time interval, 10 weeks; range, 5-34 weeks), [ 18 F] FET PET imaging proved highly performant using a TBR mean cutoff of less than 1.95 (sensitivity, 82%; specificity, 92%; positive predictive value, 90%; negative predictive value, 85%; accuracy, 87%; area under the curve AE standard error, 0.77 AE 0.12). 95 When radiation necrosis is suspected in case of gliomas or metastases, radiolabeled AAs PET may help when perfusion MRI is uncertain.…”

“…[95][96][97][98][99] In a recent study including patients with WHO grade 4 gliomas treated with lomustine-temozolomide chemoradiation and for which MRI was equivocal after radiotherapy inside the radiation field (median time interval, 10 weeks; range, 5-34 weeks), [ 18 F] FET PET imaging proved highly performant using a TBR mean cutoff of less than 1.95 (sensitivity, 82%; specificity, 92%; positive predictive value, 90%; negative predictive value, 85%; accuracy, 87%; area under the curve AE standard error, 0.77 AE 0.12). 95 When radiation necrosis is suspected in case of gliomas or metastases, radiolabeled AAs PET may help when perfusion MRI is uncertain. 36,42 However, the accuracy varies across studies (sensitivity of 74%-90%; specificity of 73%-100%); false-positive and false-negative results can occur, depending on tumor cell type and LAT activity, tracer activity related to passive diffusion across disrupted BBB and vascular volume and density associated with angiogenesis (Fig.…”