Fig. 4: Optoacoustic imaging taken in-vivo through a mouse kidney cross-section.
From: Nonlinearity of optoacoustic signals and a new contrast mechanism for imaging
a, b Reconstructed image of absorption coefficient at light fluence 1.5 ± 0.02 and 9 ± 0.1 mJ/cm2, respectively, showing the entire optoacoustic data without further processing to extract specific structures. c Image of thermally excited third-order nonlinear susceptibility \(({{\rm{\chi }}}_{{th}}^{(3)})\), reconstructed using the modified algorithm according to Eqs. (14) and (15). No post-processing, such as vessel extraction using filters like Frangi filter, was applied. The aim is to illustrate the contrast mechanisms rather than the detailed visualization of vessel structures. Arrows 1 and 2 show the skin and muscle of the abdomen, respectively. Arrows 3-6 indicate structures within the kidney (Arrow 3: Capsule, Arrow 4: Cortex, Arrow 5: Medulla, and Arrow 6: Calyx). d Anatomical reference for the kidney structures
