In vivo fluorescence imaging of the ischemic model mice using the IVIS Spectrum system. (A-D) Images using IVIS Spectrum. Unconjugated QDs and VEGF-QDs were injected intracardially into the model mice. Mice were illuminated with light with a wavelength of 625-655 nm. Excited fluorescence was filtered with a 690- to 710-nm wavelength band-pass filter. (E-G) The relative ratios of fluorescence between ischemic and control legs in mice at 4 days (E), 9 days (F), and 14 days (G) after operation. The fluorescence intensity of the ischemic leg divided by that of the control leg was calculated (ischemic leg fluorescence/control leg fluorescence). n = 5. Error bars represent SEM. **P < .05.