Diagnostic yield of simultaneous dynamic contrast-enhanced magnetic resonance perfusion measurements and [18F]FET PET in patients with suspected recurrent anaplastic astrocytoma and glioblastoma

Purpose Both amino acid positron emission tomography (PET) and magnetic resonance imaging (MRI) blood volume (BV) measurements are used in suspected recurrent high-grade gliomas. We compared the separate and combined diagnostic yield of simultaneously acquired dynamic contrast-enhanced (DCE) perfusion MRI and O-(2-[ 18 F]-fluoroethyl)-L-tyrosine ([ 18 F]FET) PET in patients with anaplastic astrocytoma and glioblastoma following standard therapy. Methods A total of 76 lesions in 60 hybrid [ 18 F]FET PET/MRI scans with DCE MRI from patients with suspected recurrence of anaplastic astrocytoma and glioblastoma were included retrospectively. BV was measured from DCE MRI employing a 2-compartment exchange model (2CXM). Diagnostic performances of maximal tumour-to-background [ 18 F]FET uptake (TBR max ), maximal BV (BV max ) and normalised BV max (nBV max ) were determined by ROC analysis using 6-month histopathological ( n = 28) or clinical/radiographical follow-up ( n = 48) as reference. Sensitivity and specificity at optimal cut-offs were determined separately for enhancing and non-enhancing lesions. Results In progressive lesions, all BV and [ 18 F]FET metrics were higher than in non-progressive lesions. ROC analyses showed higher overall ROC AUCs for TBR max than both BV max and nBV max in both lesion-wise (all lesions, p = 0.04) and in patient-wise analysis ( p