The characteristics of signal contrast for the focal hepatic masses with multi-b DWI

In order to explore the potential value of signal changes of multi-b value in diffusion-weighted imaging (DWI) for tissue characterization of the focal liver masses, 24 subjects were involved in our study. Each of them was under through eight b values (0,10, 20, 30, 50, 100, 200, 500, 800mm/sec) of DWI MR scanning using 1.5-T system. 60 focal liver lesions (11 hepatocellular carcinoma, 22 metastasis, 12 cysts, and 15 hemangiomas) were evaluated. All the focal masses were divided 3 types: cyst group, hemangioma group and other solid masses group. Both qualitative and quantitative analysis was performed. In qualitative analysis, the brightness of the signal on DWI for the hepatic cysts were decreased gradually with increasing b values. The signal contrast on DWI between hemangiomas and surrounding hepatic parenchyma were not changed with increasing b value. For other solid masses of liver, with increasing b value, the brightness of the signal on DWI were increased. In the quantitative analysis, with increasing b value, the value of S(b)/S(0) in 3 groups were decreased gradually. The degree of the reduction were varies, that is, the maximal in cyst group, the middle in the hemangioma group, and the minimal in the other solid group. Then we come to a conclusion that multi-b value DWI could be used for differentiation of hepatic cyst, hemangioma, and other solid masses without administrating contrast material.