Figure 4.

Whole body ¹⁹F/¹H images of rat thorax and abdomen 2 hours after injection of α_vβ₃-targeted or non-targeted (NT) perfluorocarbon nanoparticles (green). A. Coronal plane of rat following α_vβ₃-targeted nanoparticles showing accumulation in left lung near the pulmonary artery ligation site (adjacent to heart) and diffuse accumulation in the lung parenchyma. Marked accumulation of particles through the reticuloendothelial system (RES) in the liver and spleen is apparent. Minimal signal was detected in the right lung. B. Sagittal view of targeted nanoparticle accumulation in the left lung. C. Transverse view at the level of the heart showing bound nanoparticles in the left but not in the right lung. D. Coronal plane of rat following NT-nanoparticles showing no visual accumulation in the injured left lung adjacent to heart, but with significant RES clearance of particles into the liver and spleen. No signal is appreciated in the right lung. Similar images were observed in the sham and competition groups (i.e. little to no ¹⁹F signal in lungs). In all of the images, no off-target contrast was appreciated in surrounding musculature. The ¹H images shown above were obtained at higher resolution using a clinical 3T scanner for higher thoracic anatomical clarity. Yellow arrows indicate examples of ringing artifact recognized in this particular MRI imaging sequence, common to high signal areas (i.e. liver and spleen). ¹⁹F signal was occasionally detected in the heart, unrelated to NP treatment and most likely due to blood pool effect. The heart was consistently excluded from the lung ROI analysis.