Differentiation of High-Grade from Low-Grade Astrocytoma: Improvement in Diagnostic Accuracy and Reliability of Pharmacokinetic Parameters from DCE MR Imaging by Using Arterial Input Functions Obtained from DSC MR Imaging

Purpose: To evaluate whether arterial input functions (AIFs) derived from dynamic susceptibility-contrast (DSC) magnetic resonance (MR) imaging, or AIF(DSC) values, improve diagnostic accuracy and reliability of the pharmacokinetic (PK) parameters of dynamic contrast material-enhanced (DCE) MR imaging for differentiating high-grade from low-grade astrocytomas, compared with AIFs obtained from DCE MR imaging (AIF(DCE)). Materials and Methods: This retrospective study included 226 patients (138 men, 88 women; mean age, 52.27 years +/- 15.17; range, 24-84 years) with pathologically confirmed astrocytomas (World Health Organization grade II = 21, III = 53, IV = 152; isocitrate dehydrogenase mutant, 11.95% [27 of 226]; 1p19q codeletion 0% [0 of 226]). All patients underwent both DSC and DCE MR imaging before surgery, and AIF(DSC) and AIF(DCE) were obtained from each image. Volume transfer constant (K-trans), volume of vascular plasma space (v(p)), and volume of extravascular extracellular space (v(e)) were processed by using postprocessing software with two AIFs. The diagnostic accuracies of individual parameters were compared by using receiver operating characteristic curve (ROC) analysis. Intraclass correlation coefficients (ICCs) and the Bland-Altman method were used to assess reliability. Results: The AIF DSC -driven mean Ktrans and v(e) were more accurate for differentiating high-grade from low-grade astrocytoma than those derived by using AIF DCE (area under the ROC curve: mean K-trans, 0.796 vs 0.645, P =.038; mean v(e), 0.794 vs 0.658, P =.020). All three parameters had better ICCs with AIF DSC than with AIF DCE (K-trans, 0.737 vs 0.095; v(p), 0.848 v(s) 0.728; v(e), 0.875 vs 0.581, respectively). In AIF analysis, maximal signal intensity (0.837 vs 0.524) and wash-in slope (0.800 vs 0.432) demonstrated better ICCs with AIF DSC than AIF DCE. Conclusion: AIF(DSC)-driven DCE MR imaging PK parameters showed better diagnostic accuracy and reliability for differentiating highgrade from low-grade astrocytoma than those derived from AIF(DCE). (C) RSNA, 201