Dual-energy Spectral CT Quantitative Parameters for the Differentiation of Glioma Recurrence from Treatment-Related Changes: A Preliminary Study

Abstract Background: Differentiating glioma recurrence from treatment-related changes can be challenging on conventional imaging. We evaluated the use of dual-energy spectral computed tomographic (CT) quantitative parameters for this differentiation. Methods: Twenty-eight patients were examined by dual-energy spectral imaging CT. The slope of the spectral Hounsfield unit curve (λ HU ), effective atomic number (Z eff ), normalized effective atomic number (Z eff-N ), iodine concentration (IC), and normalized iodine concentration (IC N ) in the post-treatment enhanced areas were calculated. Pathological results or clinicoradiologic follow-up of ≥2 months were used for final diagnosis. Nonparametric and t -tests were used to compare quantitative parameters between glioma recurrence and treatment-related changes. Positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated; sensitivity and specificity were calculated using receiver operating characteristic (ROC) curves. ROC curves were generated using predictive probabilities to evaluate the diagnostic value. Results: There were no significant differences in quantitative parameters based on examination of pre-contrast λ HU , Z eff , Z eff-N , IC, IC N and venous phase IC N ( P >0.05). Venous phase λ HU , Z eff , Z eff-N , and IC in glioma recurrence were higher than in treatment-related changes ( P <0.001). The optimal venous phase threshold was 1.03, 7.75, 1.04, and 2.85 mg/cm 3 , achieving 66.7%, 91.7%, 83.3%, and 91.7% sensitivity; 100.0%, 77.8%, 88.9%, and 77.8% specificity; 100.0%, 73.3%, 83.3%, and 73.3% PPV; 81.8%, 93.3%, 88.9%, and 93.3% NPV; and 86.7%, 83.3%, 86.7%, and 83.3% accuracy, respectively. The areas under the curve (AUC) were 0.912, 0.912, 0.931, and 0.910 in glioma recurrence and treatment-related changes, respectively. Conclusions: Dual-energy spectral CT imaging may provide quantitative values to aid in differentiation of glioma recurrence from treatment-related changes.