Tumor recurrence versus treatment effects in glioma

BACKGROUND Gliomas constitute over 90% of primary brain tumors. Accurate identification of glioma recurrence and treatment effects is important, as it can help determine whether to continue with standard adjuvant chemotherapy or to switch to a second-line therapy for recurrence. Our purpose is to compare three dimensional pseudo-continuous arterial spin labeling (3D-pcASL) technique and dynamic susceptibility contrast perfusion magnetic resonance imaging (DSC-MRI) for differentiation tumor recurrence from treatment-related effects in gliomas. METHODS Twenty-nine patients with gliomas previously who showed enlarged, contrast-enhancing lesions within the radiation field after surgery and concurrent chemoradiotherapy (CCRT) were assessed with 3D-pcASL and DSC-MRI. These patients were classified into 2 groups, tumor recurrence group (n = 17) and treatment effects group (n = 12), based on pathologic analysis or clinical-radiologic follow-up. The perfusion imaging quality was assessed using a 3-point scale (1 = poor imaging, 2 = moderate imaging, and 3 = good imaging). Comparison for perfusion imaging-quality score between the 2 techniques was performed with Wilcoxon one-sample test. Quantitative analyses were performed between the 2 groups with cerebral blood flow values (ASL-CBF), relative cerebral blood flow values (ASL-rCBF, DSC-rCBF), and relative cerebral blood volume values (DSC-rCBV) using Wilcoxon one-sample test. The intra-class correlation coefficient (ICC) statistics were calculated for testing intrareader variability in regions of interest (ROIs) measurement of all perfusion parameters. RESULTS The imaging-quality score of 3D-pcASL was higher than that of DSC-MRI (P = .01). The perfusion parameters between tumor recurrence group and treatment effects group had statistically significant differences. There was a significant correlation between ASL-rCBF and DSC-rCBF values (r = 0.803), between ASL-rCBF and DSC-rCBV values (r = 0.763), and between DSC-rCBF and DSC-rCBV (r = 0.907). A receiver operating characteristic (ROC) curve analysis was performed for significant results of perfusion parameters between the 2 groups. Using a cutoff value of 1.110, ASL-rCBF showed the maximum area under the ROC curve (AUC). However, there were no significant differences among different AUCs. The ICC demonstrated excellent agreement for ROIs measurements of ASL-CBF (ICC = 0.9636), dynamic susceptibility contrast- cerebral blood flow (DSC-CBF) (ICC = 0.8508), and dynamic susceptibility contrast-cerebral blood volume (DSC-CBV) (ICC = 0.8543). CONCLUSION 3D-pcASL is an alternative perfusion method to DSC-MRI for the differentiation between tumor recurrence and treatment effects in gliomas. 3D-pcASL is noninvasive and shows fewer susceptibility artifacts than DSC-MRI.