Fig. 4.

Dual molecular MRI of cardiomyocyte apoptosis and necrosis. To distinguish between apoptotic and necrotic tissue, both AnxCLIO-Cy5.5 MRI (a, d, g) and delayed enhancement MRI of Gd-DTPA-NBD (b, e, h) are required. Images from the same animal are shown in a–h. Images at three slice locations are shown, moving progressively from the midventricular level (a, b) to the left ventricular apex (g, h). AnxCLIO-Cy5.5 was administered immediately after reperfusion and imaged after 4 h, while Gd-DTPA-NBD was administered after the T2*-weighted imaging was completed and imaged 10–30 min after injection. Only a small area in the subendocardium of the lateral wall shows delayed enhancement at the midventricular level (red arrows, b). The extent of delayed enhancement increases in the more apical slices (red arrows) and is quite extensive at the apex. Immunohistochemistry for Gd-DTPA-NBD confirms the absence or presence of probe uptake in the uninjured septum (c) and antero-apical wall (f). Within 4 h of reperfusion, the majority of myocardium with accumulation of AnxCLIO-Cy5.5 does not yet show delayed enhancement of Gd-DTPA-NBD (i). These results suggest a large amount of apoptotic but potentially viable and salvageable myocardium is thus present. Reproduced with permission from [7]