Background-The goal of this study was to characterize the performance of fluorine-19 (19F) cardiac magnetic resonance (CMR) for the specific detection of inflammatory cells in a mouse model of myocarditis. Intravenously administered perfluorocarbons are taken up by infiltrating inflammatory cells and can be detected by 19F-CMR. 19F-labeled cells should, therefore, generate an exclusive signal at the inflamed regions within the myocardium. Methods and Results-Experimental autoimmune myocarditis was induced in BALB/c mice. After intravenous injection of 2×200 μL of a perfluorocarbon on day 19 and 20 (n=9) after immunization, in vivo 19F-CMR was performed at the peak of myocardial inflammation (day 21). In 5 additional animals, perfluorocarbon combined with FITC (fluorescein isothiocyanate) was administered for postmortem immunofluorescence and flow-cytometry analyses. Control experiments were performed in 9 animals. In vivo 19F-CMR detected myocardial inflammation in all experimental autoimmune myocarditis-positive animals. Its resolution was sufficient to identify even small inflammatory foci, that is, at the surface of the right ventricle. Postmortem immunohistochemistry and flow cytometry confirmed the presence of perfluorocarbon in macrophages, dendritic cells, and granulocytes, but not in lymphocytes. The myocardial volume of elevated 19F signal (rs=0.96; P<0.001), the 19F signal-to-noise ratio (rs=0.92; P<0.001), and the 19F signal integral (r s=0.96; P<0.001) at day 21 correlated with the histological myocarditis severity score.Conclusions-In vivo 19F-CMR was successfully used to visualize the inflammation specifically and robustly in experimental autoimmune myocarditis, and thus allowed for an unprecedented insight into the involvement of inflammatory cells in the disease process.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Cardiology and Cardiovascular Medicine