Figure 4.

Representative coronal micro-CT images showing the heart, liver, jugular veins, and spleen of mice that received contrast agent formulated with (A) PPEG₂₀₀₀-GdNP and (B) PPEG₅₀₀₀-PPEG₁₀₀₀-GdNP. All times were reported from the completion of the contrast agent injection. In the 5-min image in (A), the blood in the chambers of the heart (circle), liver (arrow) and the external jugular veins (double arrowheads) are clearly visible. In the 2- and 5-day images, the blood pool in the heart is no longer visible, the liver remains visible, and the spleen (arrowheads) becomes visible. Adjacent anatomical slices were shown for the images acquired within 60 min, while slices located 1 cm posterior were shown in the 2- and 5-day images, to demonstrate the high contrast in the previously indistinguishable spleen.