A comparative study of apparent diffusion coefficient and intravoxel incoherent motion-derived parameters for the characterization of common solid hepatic tumors

Background: The performance of diffusion-weighted imaging parameters for characterizing hepatic tumors is controversial. Purpose: To compare the performances of apparent diffusion coefficient (ADC) and intravoxel incoherent motion (IVIM)-derived parameters, including the pure diffusion coefficient (D), perfusion coefficient (D*), and perfusion fraction (f), in the characterization of common solid hepatic tumors. Material and Methods: Twelve healthy volunteers and 43 patients underwent free-breath diffusion-weighted magnetic resonance imaging (DW-MRI) of the liver using eight b values (10-800 s/mm(2)). Twelve regions of interest (ROIs) of normal liver tissue in healthy volunteers and 49 hepatic lesions (23 hepatocellular carcinomas [HCCs], 16 hemangiomas, and 10 metastases) were measured. Conventional ADC((0,500)) and ADC(total) obtained by the mono-exponential model, as well as D, D*, and f were calculated. Student t-tests and receiver operating characteristic (ROC) analysis were also performed. Results: ADC((0,500)), ADC(total), and D were significantly lower in the malignant group ([1.48 +/- 0.35] x 10(-3) mm(2)/s; [1.35 +/- 0.30] x 10(-3) mm(2)/s; [1.18 +/- 0.33] x 10(-3) mm(2)/s) compared to the hemangioma group ([2.74 +/- 1.03] x 10(-3) mm(2)/s; [2.61 +/- 0.81] x 10(-3) mm(2)/s; [1.97 +/- 0.79] x 10(-3) mm(2)/s]. D* did not differ among multiple comparisons. For the area under the ROC curve (AUC-ROC), the maximum value was attained with ADC(total) (0.983) and was closely followed by ADC((0,500)) (0.967), with lower values obtained for D (0.837), f (0.649), and D* (0.599). Statistically significant differences were found between the AUC-ROC of both ADCs (ADC(total) and ADC((0,500))) and D. There was no statistically significant difference between the AUC-ROC of ADC(total) and ADC((0,500)). Conclusion: ADCs showed superior diagnostic performance compared to IVIM-derived parameters in detecting differences between the malignant group and hemangioma group.