Investigating Low-Velocity Fluid Flow In Tumors With Convection-Mri

Several distinct fluid flow phenomena occur in solid tumors, including intravascular blood flow and interstitial convection. Interstitial fluid pressure is often raised in solid tumors, which can limit drug delivery. To probe low-velocity flow in tumors resulting from raised interstitial fluid pressure, we developed a novel MRI technique named convection-MRI, which uses a phase-contrast acquisition with a dual-inversion vascular nulling preparation to separate intra-and extravascular flow. Here, we report the results of experiments in flow phantoms, numerical simulations, and tumor xenograft models to investigate the technical feasibility of convec-tion-MRI. We observed a significant correlation between estimates of effective fluid pressure fromconvection-MRI with gold-standard, invasive measurements of interstitial fluid pressure in mouse models of human colorectal carcinoma. Our results show how convection-MRI can provide insights into the growth and responsiveness to vascular-targeting therapy in colorectal cancers. Significance: A noninvasive method for measuring lowvelocity fluid flow caused by raised fluid pressure can be used to assess changes caused by therapy. (C) 2018 AACR.