CONTRAST-ENHANCED SONOGRAPHY OF TUMOR NEOVASCULARITY IN A RABBIT MODEL

This project was designed to detect the development of tumor neovascul arity and determine if intravenous microbubble contrast improves visua lization of otherwise undetectable tumors in an animal model. VX-2 car cinoma was implanted into one thigh of 10 New Zealand white rabbits. T umors were assessed without and with contrast at 1- to 4-day intervals from day 3-19 postimplantation, using gray scale, color flow, pulse D oppler and power Doppler imaging. Tumor vascularity was compared with the contralateral thigh muscle, so each animal was its own control. Co ntrast injection improved visualization of tumor neovascularity, Early tumors had homogeneous vasculature but, with time, the centers became less vascular, while the periphery increased. Following contrast inje ction, color gain was decreased by 40% without compromising color inte nsity. Neovascularity was detected by contrast injection before the tu mor could be palpated or visualized by gray scale. Based on these data , we conclude that enhancement of neovascularity by intravenous contra st permits earlier detection and improved visualization of soft tissue tumors in rabbits. (C) 1998 World Federation for Ultrasound in Medici ne & Biology.