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-[<sup>18</sup>F]-fluoroethyl)-L-tyrosine ([<sup>18</sup>F]FET) PET in patients with anaplastic astrocytoma and glioblastoma following standard therapy.
METHODS: A total of 76 lesions in 60 hybrid [<sup>18</sup>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 [<sup>18</sup>F]FET uptake (TBR<sub>max</sub>), maximal BV (BV<sub>max</sub>) and normalised BV<sub>max</sub> (nBV<sub>max</sub>) 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 [<sup>18</sup>F]FET metrics were higher than in non-progressive lesions. ROC analyses showed higher overall ROC AUCs for TBR<sub>max</sub> than both BV<sub>max</sub> and nBV<sub>max</sub> in both lesion-wise (all lesions, p = 0.04) and in patient-wise analysis (p < 0.01). Combining TBR<sub>max</sub> with BV metrics did not increase ROC AUC. Lesion-wise positive fraction/sensitivity/specificity at optimal cut-offs were 55%/91%/84% for TBR<sub>max</sub>, 45%/77%/84% for BV<sub>max</sub> and 59%/84%/72% for nBV<sub>max</sub>. Combining TBR<sub>max</sub> and best-performing BV cut-offs yielded lesion-wise sensitivity/specificity of 75/97%. The fraction of progressive lesions was 11% in concordant negative lesions, 33% in lesions only BV positive, 64% in lesions only [<sup>18</sup>F]FET positive and 97% in concordant positive lesions.
CONCLUSION: The overall diagnostic accuracy of DCE BV imaging is good, but lower than that of [<sup>18</sup>F]FET PET. Adding DCE BV imaging did not improve the overall diagnostic accuracy of [<sup>18</sup>F]FET PET, but may improve specificity and allow better lesion-wise risk stratification than [<sup>18</sup>F]FET PET alone.
|Journal||European Journal of Nuclear Medicine and Molecular Imaging|
|Number of pages||15|
|Publication status||Published - Nov 2022|
- Magnetic resonance imaging
- Perfusion imaging
- Blood volume
- Positron emission tomography
- Amino acid tracers
- Magnetic Resonance Spectroscopy
- Magnetic Resonance Imaging/methods
- Brain Neoplasms/pathology
- Glioblastoma/diagnostic imaging
- Astrocytoma/diagnostic imaging
- Retrospective Studies
- Positron-Emission Tomography/methods