Guanshu Liu1,2, Yah-el Har-el2, Chris Long3, Assaf A. Gilad2,4, George Sgouros2, Jeff W.M. Bulte2,4, Peter C.M. van Zijl1,2, Michael T. McMahon1,2
1F.M. Kirby Center, Kennedy Krieger Institute, Baltimore, MD, USA; 2Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; 3Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD; 4Institute for Cellular Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
In order to facilitate the noninvasive detection of lymphatic delivery of anticancer drugs, we developed a new MRI-visible liposome system based on labeling with the diamagnetic Chemical Exchange Saturation Transfer (DIACEST) agent L-arginine. Using B0-corrected CEST-MRI, the accumulation of liposome in the popliteal lymph node could be visualized in vivo in mice (n = 3). To validate the approach, liposomes were simultaneously labeled with a fluorescent chromophore, the fluorescence of which correlated with the CEST intensity. This new DIACEST liposome system allows direct visualization of drug delivery to the lymph nodes without using paramagnetic material.