Letter by Jansen and van Royen Regarding Article, “Monitoring of Monocyte Recruitment in Reperfused Myocardial Infarction With Intramyocardial Hemorrhage and Microvascular Obstruction by Combined Fluorine-19 and Proton Cardiac Magnetic Resonance Imaging”

To the Editor:

We read with interest the article by Ye et al¹ on the use of combined fluorine 19/proton magnetic resonance imaging (MRI) to visualize the spatiotemporal recruitment of monocytes in vivo in a rat model of reperfused myocardial infarction. On the basis of this study, it is suggested that intramyocardial hemorrhage often occurs without microvascular obstruction and that monocyte recruitment is highly reduced in areas containing microvascular obstruction. Furthermore, in their histological analysis, the authors describe “islands” lacking monocytes inside an area of intramyocardial hemorrhage. They conclude that these islands must be the microvascular obstruction as determined by MRI and that intramyocardial hemorrhage in combination with these …