Bentley, Michael D

Despite the importance of the vasculature during tumorigenesis and during antiangiogenesis treatment, there are few methods available to visualize conveniently the three‐dimensional microvascular structure of tumors. Micro‐computed tomography provides a means to visualize conveniently and quantitatively the three‐dimensional tumor microvascular architecture during tumorigenesis and treatment. In the present study, micro‐computed tomography was utilized to visualize the vasculature of hepatic tumors in SV‐40 transgenic rats. The rats were anesthetized and the vasculature of the livers was infused via an aortic cannula, first with heparinized 0.9% saline, then with 10% buffered formalin and finally with radiopaque silicone rubber (Microfil 122). The livers were first scanned by micro‐CT to visualize the microvasculature and then prepared for histology to visualize the parenchyma. At 10 months of age, all transgenic rats developed gross tumors in their livers. Histological examination revealed that the malignant hepatic lesions in the livers displayed mixed structures resembling hepatoblastoma, cholangiocellular or hepatocellular differentiation in human. Various sized vessels were visible extending to the tumors. Three‐dimensional micro‐computed tomography showed that those vessels were disorganized and tortuous with atypical branching patterns. Often vascular “lakes” were found in the mass of the large tumors. These results show the utility of micro‐computed tomography for studying tumor vasculogenesis. Supported in part by NIH grant EB 000305.