Abstract
BACKGROUND
Glioma often recurs and the imaging evaluation whether the tumor has returned after glioma treatment is still challenging. PET/CT is one of the most important techniques to assess the post-treatment of glioma. However, differentiating tumor recurrence (TuR) from treatment effects (TrE) remains difficult. In this study, we aim to retrospectively compare the diagnostic performance of three PET tracers 13N-NH3, 18F-DOPA, and 18F-FDG on PET/CT in differentiating between TuR and TrE in post-treatment glioma patients.
METHODS
Forty-three patients with MRI-suspected recurrent glioma were included. The maximum and mean standardized uptake value (SUVmax and SUVmean) of the lesion and the lesion-to-normal Gray-matter cortex uptake (L/G) ratio were recorded and the reference standard was verified by surgical histopathology or more than 6 months of follow-up with clinical/radiological. The diagnostic performance was evaluated using receiver operating characteristic (ROC) analysis.
RESULTS
34 patients were confirmed as glioma TuR and 9 patients met the standard of TrE. The median time interval from primary diagnosis surgery to PET/CT was 14.83 months (range, 4.10-62.77 months). The SUVmax of 13N-NH3 and 18F-DOPA PET/CT at the lesions was significantly higher than normal brain tissue (13N-NH3 0.696±0.095 vs 0.486±0.071, 18F-DOPA 0.455±0.079 vs 0.194±0.031, both P< 0.001), while 18F-FDG was not (6.918±0.525 vs 6.356±0.510, P=0.290). TuR showed significantly higher L/G ratios than TrE both in 13N-NH3 and 18F-DOPA PET/CT (13N-NH3, 1.573±0.099 vs 1.025±0.128, P=0.008; 18F-DOPA, 2.729±0.131 vs 1.514±0.141, P< 0.001). The sensitivity, specificity and the area under the curve (AUC) by ROC analysis were 57.7, 100% and 0.803 for 13N-NH3, and 84.6, 100% and 0.938 for 18F-DOPA respectively.
CONCLUSIONS
PET/CT is a powerful tool to distinguish glioma TuR from TrE, and 18F-DOPA PET/CT has remarkably better differential diagnosis efficacy than 13N-NH3 and 18F-FDG.