Interrogation of Fluctuating Tumour Microvasculature Using Combined Carbogen-USPIO (CUSPIO) Imaging

Jake Samuel Burrell¹, John C. Waterton², Anderson Ryan², Simon P. Robinson¹, Simon Walker-Samuel¹

Combined carbogen-USPIO (CUSPIO) imaging was used to investigate microvascular fluctuations SW1222 and HCT116 colorectal xenografts. CUSPIO exploits the inherent size difference in the mechanism of action of carbogen (95% O₂, 5% CO₂) and USPIO imaging (erythrocytes compared to nano-particles). Small vessels allow favourable entry to the USPIO particles. By producing δR2* maps temporal changes in vascular perfusion can be evaluated. This technique revealed a difference in the vascular stability of the two tumour types which has important implications for drug trials. This result suggests that CUSPIO imaging is a potentially useful method for imaging transient vascular shutdown in vivo.