Fig. 3.

Breathing correction and kinetics of AuNRs perfusion in vivo. (a-d) optoacoustic images of mouse abdomen showing the left and right kidneys (arrows) at four different breathing points: (a) expiratory pause, (b) inhalation, (c) respiratory peak and (d) exhalation. The SSIM was used here as a metric to quantify the breathing motion between the expiratory frame (reference) and the other frames. (e) Normalized optoacoustic signal in the mouse abdomen across the injection time point showing breathing motion artifacts. Animals were injected with AuNRs over the indicated interval in order to enhance vessels. (f) Visualization of the AuNR perfusion in the selected expiratory frames after breathing correction.