Fig. 2.  In vivo  homing of macrophages and neutrophils to the inflamed peritoneum can be detected by fluorescence-mediated tomography. Four hours before induction of peritonitis, mice received an intravenous (IV) injection of 10⁷double-labeled enhanced green fluorescent protein (eGFP) transgenic and 1,1′-dioctadecyl-3,3,3′,3′- tetramethylindotricarbocyanine iodide (DiR)-stained macrophages or 5 × 10⁶DiR-labeled neutrophils. (A ) To detect indicator leukocytes that had homed into the peritoneum, baseline fluorescence-mediated tomography (FMT) scans were performed after intravenous injection of indicator cells but before thioglycollate (thio) injection (d0). (B ) Four of 30 sequential tomographic images (Z3–Z6) per time point are displayed for two animals that received indicator macrophages. (C ) Consistent with flow cytometry and microscopic cell counts (see Supplemental Digital Content 1, Flow Cytometry Confirms Fluorescence-mediated Tomography Measured Cell Recruitment section, https://links.lww.com/ALN/A606), fluorescence-mediated tomography scans revealed a significantly enhanced macrophage derived mean fluorescence intensity (MFI) in thioglycollate-injected mice (open square ) compared with controls (cont., closed circles ) (n = 9/10; *P < 0.05). (D ) Mice that received DiR-labeled neutrophils intravenously demonstrated a significant increase in abdominal fluorescence intensity 4 h after thioglycollate injection, whereas no difference could be detected in control animals (n = 6; *P < 0.02).