In Vivo Fluorine Imaging Using 1.5 Tesla MRI for Depiction of Experimental Myocarditis in a Rodent Animal Model

Thore Dietrich; Stephan Theodor Bujak; Thorsten Keller; Bernhard Schnackenburg; Riad Bourayou; Rolf Gebker; Kristof Graf; Eckart Fleck

doi:10.1155/2023/4659041

In Vivo Fluorine Imaging Using 1.5 Tesla MRI for Depiction of Experimental Myocarditis in a Rodent Animal Model

Int J Biomed Imaging. 2023 Jul 14:2023:4659041. doi: 10.1155/2023/4659041. eCollection 2023.

Authors

Thore Dietrich¹, Stephan Theodor Bujak^{1

2

3}, Thorsten Keller^{1

4}, Bernhard Schnackenburg⁵, Riad Bourayou¹, Rolf Gebker¹, Kristof Graf⁶, Eckart Fleck¹

Affiliations

¹ Department of Cardiology, Deutsches Herzzentrum Berlin, Berlin 13353, Germany.
² Department of Geriatrics, Krankenhaus Hedwigshöhe, Alexianer St. Hedwig Kliniken Berlin GmbH, Berlin 12526, Germany.
³ Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany.
⁴ B. Braun Melsungen AG, Melsungen 34212, Germany.
⁵ Philips Healthcare, Hamburg 22335, Germany.
⁶ Department of Cardiology, Jüdisches Krankenhaus Berlin, Berlin 13347, Germany.

Abstract

The usefulness of perfluorocarbon nanoemulsions for the imaging of experimental myocarditis has been demonstrated in a high-field 9.4 Tesla MRI scanner. Our proof-of-concept study investigated the imaging capacity of PFC-based ¹⁹F/¹H MRI in an animal myocarditis model using a clinical field strength of 1.5 Tesla. To induce experimental myocarditis, five male rats (weight ~300 g, age ~50 days) were treated with one application per week of doxorubicin (2 mg/kg BW) over a period of six weeks. Three control animals received the identical volume of sodium chloride 0.9% instead. Following week six, all animals received a single 4 ml injection of an 20% oil-in-water perfluorooctylbromide nanoemulsion 24 hours prior to in vivo¹H/¹⁹F imaging on a 1.5 Tesla MRI. After euthanasia, cardiac histology and immunohistochemistry using CD68/ED1 macrophage antibodies were performed, measuring the inflamed myocardium in μm² for further statistical analysis to compare the extent of the inflammation with the ¹⁹F-MRI signal intensity. All animals treated with doxorubicin showed a specific signal in the myocardium, while no myocardial signal could be detected in the control group. Additionally, the doxorubicin group showed a significantly higher SNR for ¹⁹F and a stronger CD68/ED1 immunhistoreactivity compared to the control group. This proof-of-concept study demonstrates that perfluorocarbon nanoemulsions could be detected in an in vivo experimental myocarditis model at a currently clinically relevant field strength.