Chalermchai Khemtong1, Chase W. Kessinger1, Jimin Ren2, Erik A. Bey1, Su-Geun Yang1, Jagadeesh Setti Guthi1, David A. Boothman1, A Dean Sherry2, Jinming Gao1
1Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA; 2The Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
Magnetic resonance imaging (MRI) is a powerful clinical imaging technique that allows for non-invasive tomographic visualization of anatomic structures with high spatial resolution and soft tissue contrast. However, its application in molecular imaging of cancer has been limited by the lack of sensitivity and detection accuracy in depicting the biochemical expression of these diseases. Here, we combine an ultra-sensitive design of superparamagnetic polymeric micelles (SPPM) and an off-resonance saturation (ORS) method to enhance the imaging efficacy of tumor biomarkers in vivo. SPPM nanoparticles encoded with cyclic(RGDfK) were able to target the αvβ3-expressing microvasculature in A549 non-small cell lung tumor xenografts in mice. ORS greatly improved tumor detection accuracy over the conventional T2*-w method by its ability to turn ON the contrast of SPPM. This combination of ORS imaging with a tumor vasculature-targeted, ultra-sensitive SPPM design offers new opportunities in molecular imaging of cancer.