(18) F-FDG PET/MR imaging in patients with suspected liver lesions: Value of liver-specific contrast agent Gadobenate dimeglumine

OBJECTIVES: To evaluate the added value of the application of the liver-specific contrast phase of Gadobenate dimeglumine (Gd-BOPTA) for detection and characterization of liver lesions in (18)F-FDG PET/MRI. METHODS: 41 patients with histologically confirmed solid tumors and known / suspected liver metastases or not classifiable lesions in (18)F-FDG PET/CT were included in this study. All patients underwent a subsequent Gd-BOPTA enhanced (18)F-FDG PET/MRI examination. MRI without liver-specific contrast phase (MRI(1)), MRI with liver-specific contrast phase (MRI(2)), (18)F-FDG PET/MRI without liver-specific contrast phase (PET/MRI(1)) and with liver-specific contrast phase (PET/MRI(2)) were separately evaluated for suspect lesions regarding lesion dignity, characterization, conspicuity and confidence. RESULTS: PET/MRI datasets enabled correct identification of 18/18 patients with malignant lesions; MRI datasets correctly identified 17/18 patients. On a lesion-based analysis PET/MRI(2) provided highest accuracy for differentiation of lesions into malignant and benign lesions of 98% and 100%. Respective values were 95% and 100% for PET/MRI(1), 93% and 96% for MRI(2) and 91% and 93% for MRI(1). Statistically significant higher diagnostic confidence was found for PET/MRI(2) and MRI(2) datasets compared to PET/MRI(1) and MRI(1,) respectively (p < 0.001). CONCLUSION: The application of the liver-specific contrast phase in (18)F-FDG PET/MRI further increases the diagnostic accuracy and diagnostic confidence for correct assessment of benign and malignant liver lesions.