Tumor Vascularity: Evaluation in a Murine Model with Contrast-enhanced Color Doppler US—Effect of Angiogenesis Inhibitors

PURPOSE: To determine the ability of contrast material–enhanced ultrasonography (US) to depict tumor growth and vascularity in a murine model of prostate carcinoma treated with an angiogenic inhibitor. MATERIALS AND METHODS: Thirty-five genetically engineered mice with spontaneously occurring prostate tumors were monitored on a weekly basis with gray-scale and color Doppler US with a 15-MHz linear transducer. Eighteen mice were treated with an adenoviral vector to deliver a soluble form of the Flk1 receptor (VEGFR-2), a vascular endothelial growth factor receptor designed to block tumor angiogenesis. The remaining 17 animals were injected with saline and used as controls. Tumor volumes were calculated on the basis of serial US measurements. Color Doppler US was performed in every tumor before and after intravenous injection of 0.1 mL per kilogram of body weight of a US contrast agent. US images were evaluated for tumor size, pattern of vascularity, and extent of vascularity (vascularity index). Findings a...