The following is a summary of “Visualization of intradermal blood vessel structures by dual-wavelength photoacoustic microscopy and characterization of three-dimensional construction of livedo-racemosa in cutaneous polyarteritis nodosa,” published in the May 2024 issue of Dermatology by Sujino, et al.

Photoacoustic microscopy holds promise as a noninvasive and three-dimensional (3D) imaging technique for observing intradermal structures, offering potential clinical applications. For a study, researchers sought to assess the feasibility of a photoacoustic microscope equipped with two types of pulsed lasers for simultaneous visualization of hemoglobin and melanin, particularly in various skin lesions.

Sixteen skin lesions, including erythema, pigmented lesions, vitiligo, and purpura, were analyzed to visualize the 3D structure of melanin granule distribution and dermal blood vessels. Thirteen cases of livedo racemosa in cutaneous polyarteritis nodosa (cPN) were further examined to visualize the 3D structure of dermal blood vessels in detail. Vascular structure was also analyzed in biopsy specimens obtained from tender indurated erythema of cPN using CD34 immunostaining.

The hemoglobin-recognition signal effectively visualized the 3D structure of dermal blood vessels, while the melanin-recognition signal was consistently reduced in vitiligo. In livedo racemosa, the hemoglobin-recognition signal revealed a distinct reticular structure in deeper layers, becoming denser towards the upper layers. Numerical analysis indicated a significantly higher number of dermal blood vessels in the lesion’s deeper region than normal skin (P<0.05). CD34 immunohistochemical analysis in tender indurated erythema demonstrated an increased number of dermal vessels compared to normal skin in 88.9% (8/9) of cases, indicating vascular network remodeling in cPN.

The photoacoustic system offered advantages in noninvasively detecting dermal blood vessel structures, which were challenging to recognize through two-dimensional histopathology specimen examination. Its potential utility extends to various skin diseases, warranting further evaluation.

Reference: sciencedirect.com/science/article/pii/S0923181124000562