A comparison between four- and two-dimensional contrast-enhanced ultrasonographic imaging techniques as applied to liver tumor diagnosis

Objective To demonstrate the advantages of four-dimensional contrast-enhanced ultrasonography(4DCEUS) over two-dimensional contrast-enhanced ultrasonography(2D-CEUS) in the diagnosis of liver tumors. Methods 4D- and 2D-CEUS images were obtained in 19 liver tissues from 17 patients.After a venous bolus injection of SonoVue,images of every phase were recorded,and a comparison between the two imaging techniques was made. Results In both 4D-CEUS and 2D-CEUS,primary carcinoma of the liver showed fast enhancement in the arterial phase.During portal venous and late phases,the contrast agent was rapidly washed out.In the arterial phase,the hemangiomas exhibited a centripetal enhancement.During portal venous and late phases,the contrast agent was slowly washed out.Liver metastases showed enhancement only in the periphery(' rim enhancement') during the later arterial phase,and appeared as dark defects in the portal and late phases.After interventional therapy for the primary carcinoma, hypoechoic enhancement was observed during the three phases.In 4D-CEUS,the details of tumors were revealed with great clarity in a dynamic fashion.There were more vasa vasorums observed around the tumor,and more vessels detected inside the lesion.Conclusions Compared with conventional 2D-CEUS,4D-CEUS provides improved visualization of liver tumors in general and more perceptible information on the spatial relationship between the vasa vasorums and the target tumor in particular.This technique can be used as a new,complementary method in the diagnosis of liver tumors.