Diagnostic Accuracy of Dynamic Gadoxetic-Acid-Enhanced MRI and PET/CT Compared in Patients With Liver Metastases From Neuroendocrine Neoplasms

Purpose: To evaluate the diagnostic accuracy of dynamic-contrast-enhanced (DCE) MRI in comparison to both F-18-FDG-and Ga-68-DOTATATE-PET/CT in patients with liver metastases of neuroendocrine neoplasms (NEN). Materials and Methods: Thirty-two patients with hepatic metastases from NEN were examined both in DCE-MRI and positron emission tomography/computed tomography (PET/CT), using either F-18-fluorodeoxyglucose (F-18-FDG) or Ga-68-DOTATATE as tracer. DCE-MRI was performed at 3 Tesla with Gd-EOB-DTPA acquiring 48 slices every 2.2 s for 5 min. Three regions of interest (ROIs) representing liver background and liver metastases were defined in fat-saturated T1w three-dimensional GRE MRI sequences in the hepatobiliary phase. Corresponding ROIs were then defined in the DCE-MRI-and in the PET/CT-dataset. Area under the curve (AUC) was calculated for the differentiation between metastases and liver background for DCE-MRI and PET-CT parameters. Results: AUC was very high for SUVmean (mean standardized uptake value) derived from Ga-68-DOTATATE(AUC=0.966), and F-18-FDG-PET/CT (AUC=0.989). For DCE-MRI parameters, arterial flow fraction and intracellu-lar uptake fraction showed the highest AUCs (AUC=0.826, AUC=0.819, respectively). The combination of those two had an AUC of 0.949. The combination of DCE-MRI and PET-CT parameters resulted in the highest AUC. Conclusion: Both PET/CT parameters and DCE-MRI perfusion parameters show a high diagnostic accuracy in the distinction between liver metastases and liver tissue. Our data suggest that both modalities provide complementary information.