Valeria Righi1,2, Dionyssios Mintzopoulos1,2,
Ovidiu C. Andronesi1,2, Jianxin He3, George Dai2,
Laurence G. Rahme3, A Aria Tzika1,2
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.