Fig. 3.

Real-time photoacoustic monitoring of blood perfusion in a finger during brachial cuffing and after release. PA MAP images (a) during and (b) after branchial cuffing. (a1, a2) PA B-mode images cut along lines (i) and (ii) in (a), respectively, and (b1, b2) PA B-mode images cut along lines (i) and (ii) in (b), respectively. (c, d) PA depth-encoded images of (a) and (b), respectively. Depth refers to the distance from the skin surface. (e, f) PA B-mode images with and without the cuff respectively, during continuous PA B-mode imaging near line (iii) in (a). (g) Relative change in vessel density over time. The cuff was released at 15 s. After the cuff is released, the vessel density increases for 10.6 s, and stays the same thereafter. All scale bars are 200 μm. PA, photoacoustic, and MAP, maximum amplitude projection.