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

Figures

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  Figure 1. Experimental design used in this study. Animals from the doxorubicin group (upper part of the graphics) or from the control group (lower part) received 6 weekly injections before receiving a single (4 mL) injection of PFC-laden nanoparticles prior to MR-imaging. The animals were then euthanized, and their myocardium was investigated by means of histology and immunohistochemistry.

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  Figure 2. A MIP of the overlaid 19F signal over the anatomical scan in 1.5 Tesla MRI: (a) The fluorine in the liver is predominant on the image, and small signals in other organs are merely visible. Through cluster analysis, unspecific signals can be identified and subsequently excluded from the visualization by recomputing the colormap, leading to (b). The visual identification of weaker 19F enhancements (the marker M stands for the signal in the myocardium in this example) is thus facilitated.

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  Figure 3. 19F signal (color overlay) over the 1H anatomical scan in 1.5 Tesla MRI (black and white). The red label “M” marks the myocardial fluorine signal. All other displayed signals are attributed to enhancement in the lymph nodes, especially in the dorsal thoracic region, where a large collection of lymph nodes near the shoulder blades is located [21].

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  Figure 4. Statistical analysis of the SNR in a myocardial ROI. The signal of the doxorubicin group was significantly higher compared to the control group (4.56 ± 1.19 vs. 2.03 ± 0.39; p = 0.036).

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  Figure 5. (a) Statistical analysis of macrophage CD68/ED1 staining using boxplot graphs shows the statistically significant enhancement in the doxorubicin group. (b) For the eight animals in total in the doxorubicin and control groups the plot shows the correlation between the SNR of fluorine enhancement in the myocardium (MRI, a picture of the 19F/1H overlay is shown on top of the y-axis) and the strength of the macrophage infiltration (CD68/ED1 histological staining, a picture is presented at the end of the abscissa displaying the areas above the color threshold in green) (significance level p < 0.05).