CXCR4 and myocardial infarction: In one study, uptake of the CXCR4-targeted tracer 68Ga-pentixafor peaked in the infarct region 3 days post-myocardial infarction in mice and corresponded with a flow cytometry-based peak of circulating CD45+ leukocytes and histological staining of macrophages and granulocytes within the infarct [40].