P3I-1 Functional Ultrasound Contrast of Renal Tumors in a Mouse Model

The goal of this work is to apply ultrasonic contrast techniques for noninvasive, in vivo, monitoring of Wilms´ tumor angiogenesis in the mouse. Tumors were induced by renal subcapsular injection of human tumor cells in nude mice (N = 56). At 18, 21, 27 and 28 days after tumor-cell injection, contrast imaging was performed with an Acuson Sequoia (7-14 MHz, contrast pulse sequence mode). Estimates of the characteristic refill time and fractional blood volume of tumors were obtained from fitting destruction/reperfusion curves to the established model. The fractional blood volume was between 0.002 and 0.8 times that in the cortex. The transit time was on the order of 3 times slower in the tumor than the cortex. The fractional blood volume in the tumor tended to increase as the % of nonnecrotic tissue in the tumor (r² = 0.38, p < 0.05) and the MVD (r² = 0.46, p < 0.01) increased. Validation of contrast ultrasound techniques in this model represents an important step towards their application for the noninvasive evaluation of different therapeutic approaches