Characterizing focal hepatic lesions by free-breathing intravoxel incoherent motion MRI at 3.0 T

Background: Diffusion-weighted (DW) imaging is commonly used to distinguish between benign and malignant liver lesions. Purpose: To prospectively evaluate the true molecular-diffusion coefficient (D), perfusion-related diffusion coefficient (D∗), perfusion fraction (f), and ADC of focal hepatic lesions using a free-breathing intravoxel incoherent motion (IVIM) DW sequence, and to determine if these parameters are useful for characterizing focal hepatic lesions. Material and Methods: One hundred and twenty hepatic lesions (34 metastases, 32 hepatocellular carcinoma [HCC], 33 hemangiomas, and 21 liver cysts) in 74 patients were examined. Mean D, D∗, f, and ADC values of hepatic lesions were compared among pathologies. ROC curve analyses were performed to assess the performances of D, D∗, f, and ADC values for the characterization of liver lesions as benign or malignant. Results: The mean D and ADC values of benign lesions were greater than those of malignant lesions (P<0.001). Although the mean D and ADC values of liver cysts were greater than those of hemangiomas (P<0.001), and these values were not significantly different between metastases and HCCs (P=0.99). Area under the ROC curve for ADC values (0.98) was significantly greater (P=0.048) than that for D values (0.96) for the differentiation of benign and malignant lesions. Sensitivity and specificity for the detection of malignant lesion were 89% and 98%, respectively, when an ADC cut-off value of 1.40 was applied. Conclusion: D and ADC values have more potential for characterizing focal hepatic lesions than D∗ or f values, and for the differentiation of malignancy and benignity.