In Vivo Off Resonance Saturation Magnetic Resonance Imaging of αvβ3-Targeted Superparamagnetic Nanoparticles

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 due to the lack of sensitivity and detection accuracy in identifying the biological processes of this disease. Recently, superparamagnetic nanoparticles have received considerable attention as molecular imaging probes with substantially higher molar relaxivities over small molecular T1 agents. Conventionally, T2*-weighted (T2*-w) method serves as the gold standard for the imaging of superparamagnetic probes. However, this method typically requires a pre-contrast scan and a post-contrast scan to visually detect contrast changes, and is prone to image artifacts due to B0 inhomogeneity. Herein, we combine an ultra-sensitive design of cancer-targeted superparamagnetic polymeric micelles (SPPM) and an off-resonance saturation (ORS) method to enhance the imaging efficacy of tumor biomarkers in vivo.