SUBHARMONIC AIDED PRESSURE ESTIMATION FOR MONITORING INTERSTITIAL FLUID PRESSURE IN TUMORS: CALIBRATION AND TREATMENT WITH PACLITAXEL IN BREAST CANCER XENOGRAFTS

摘要

This project noninvasively estimated interstitial fluid pressure (IFP) in rats with breast cancer xenografts using subharmonic aided pressure estimation (SHAPE) versus an invasive pressure monitor. Moreover, monitoring of IFP changes after chemotherapy was assessed. Eighty-nine rats (calibration n=25; treatment n=64) were injected with 5×106 breast cancer cells (MDA-MB-231). RF signals were acquired (39 rats successfully imaged) with a Sonix RP scanner (BK Ultrasound, Richmond, BC, Canada) using a linear array (L9–4; transmit/receive: 8/4MHz) after administration of Definity (Lantheus Medical Imaging, N Billerica, MA; 180μl/kg) and compared to an invasive pressure monitor (Stryker, Berkshire, UK). An inverse linear relationship was established between tumor IFP and SHAPE (y=−1.06x+28.27; r=−0.69; p=0.01) in the calibration group. Using this relationship in the treatment group resulted in r=0.74 (p<0.05) between measured (pressure monitor) and SHAPE-estimated IFP (average error 6.24mmHg). No significant differences were seen before/after paclitaxel treatment (5mg/kg, Mayne Pharma, Paramus, NJ) with either method (p≥0.15).