Imaging the Relationship between Tumour Interstitial Fluid Velocity & Microvascular Perfusion with ConvectionMRI

Simon Walker-Samuel¹, Jake Burrell², Rajiv Ramasawmy¹, Peter Johnson³, Jack Wells¹, Bernard Siow¹, Simon P. Robinson², Barbara Pedley³, Mark F. Lythgoe¹

High tumour interstitial fluid pressure (IFP) is hypothesised to be caused by raised vascular permeability and thus driven by microvascular pressure. We have developed a novel method for measuring tumour interstitial fluid velocity (IFV) named convectionMRI that can map the path of fluid transport through the tumour interstitium. By combining this technique with arterial spin labelling to evaluate vascular perfusion, we have shown a correspondence between IFV spatial distribution, vascular perfusion and spatial pressure gradients that are consistent with this microvascular pressure hypothesis. We discuss the potential for the non-invasive assessment of barriers to drug delivery.