Fig. 7
Ex-vivo validation of T2*-weighted CMR for detection of intramyocardial hemorrhage. A short-axis view of a formalin fixed heart from an animal captured with a photograph (A) and 3 T ex-vivo CMR (B) in the chronic phase MI from one animal are shown. Arrows point to chronic MI territories with history of hemorrhagic MI. Paraffin-fixed myocardial sections (infarcted and remote) stained with Prussian blue from an animal are shown (C, D). Note that the infarcted regions show evidence of iron (blue stains, arrow heads, C) consistent with history of hemorrhagic infarction, which is not evident in the remote territory (D). E shows the American Heart Association segmentation with IMH extent within each segment. Generally, there was good agreements of segmental IMH extent between ex-vivo segments and bright- and dark-blood images. However, one of the segments in dark-blood T2*-weighted images was not identified to be positive for IMH (< 1%) relative to the ex-vivo and bright-blood T2*-weighted images. F shows strong correlation of IMH extent (as fraction of whole LV volume) between in-vivo bright-blood T2*-weighted CMR and ex-vivo T2*-weighted CMR across all animals (y = 0.92x + 0.15, R2 = 0.88, p < 0.05). The same panel also shows very good correlation between in-vivo dark-blood T2*-weighted CMR and ex-vivo T2*-weighted CMR across all animals (y = 0.71x + 0.20, R2 = 0.81, p < 0.05)