Kannie W. Y. Chan1,2, April M. Chow1,2,
Ed X. Wu1,2
1Laboratory of Biomedical Imaging and
Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR,
China; 2Department of Electrical and Electronic Engineering, The
University of Hong Kong, Pokfulam, Hong Kong SAR, China
MR
susceptibility contrast agents have been used for imaging of vasculature and
tumors, such as microbubbles and iron oxides. We have developed a
susceptibility agent for pH sensing, especially for acidic tumor environment,
increasing sensitivity around physiological pH using liposome-loaded
microspheres. Our in vitro data showed that both R2 and R2* decreased at low
pH, and the percentage change in R2* is larger when compared to controls at
pH 6.8-7.2. Liposome-loaded microspheres showed a substantial increase in pH-dependence
of R2*, which favoured by localization of liposomes on microspheres, and is
first demonstrated to an improve pH sensitivity at 7T.