Abstract #4936

Combined Off-Resonance Imaging and Relaxation in the Rotating Frame for Positive Contrast Imaging of Infection in a Murine Burn Model

Valeria Righi^1,2, Dionyssios Mintzopoulos^1,2, Ovidiu C. Andronesi^1,2, Jianxin He³, George Dai², Laurence G. Rahme³, A Aria Tzika^1,2

¹NMR Surgical Laboratory, Department of Surgery, Massachusetts General Hospital and Shriners Burns Institute, Harvard Medical School, Boston, MA, United States; ²Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Boston, MA, United States; ³Molecular Surgery Laboratory, Department of Surgery, Massachusetts General Hospital and Shriners Burns Institute, Harvard Medical School, Boston, MA, United States

We employed positive-contrast MRI in a murine model of burn and infection. We used off-resonance imaging (ORI) and a novel method of combining off-resonance imaging and relaxation in the rotating frame (ORI-T2ρ). We imaged accumulation of ultra-small super-paramagnetic iron oxide (USPIO) nanoparticle-labeled macrophages at the infection site in mice, which were burned and infected with Pseudomona aeruginosa. We concluded that ORI-T2ρ is more sensitive than ORI in detecting USPIOs and that we can successfully detect infection with positive contrast imaging, which opens up perspectives for monitoring infection and testing anti-infectives.