MR Assessment of Acute Pathologic Process after Myocardial Infarction in a Permanent Ligation Mouse Model: Role of Magnetic Nanoparticle-Contrasted MRI

Figure 1

MRI images were acquired at 1 day (LGE: a, g), 2 days (MEMRI: b, h), and 3 days (MNP-MRI: c, i) after induction of myocardial infarction (MI). Histological examination of the mouse heart was performed at 3 days after MI (d, j). Representative cardiac MRI images and corresponding histological images are shown. Images in the upper row were acquired from anterolateral LV wall infarction (a–f) and bottom row images were obtained from entire LV free wall infarction (g–l). The infarcted myocardium appears hyperintense in LGE and hypointense in MEMRI images, and the corresponding infarct region is evident in a immunohistochemistry stain for myoglobin (d, j); myoglobin-positive areas (dark blue) are viable myocardium. MNP- (red) and CD68-positive (green) regions are consistent with hypointense signals in MNP-MRI representing inflammatory areas after myocardial infarction (e, k). Colocalization of MNPs with macrophages is observed in the peri-infarct zone (f, l).