Comparative study on high-frequency ultrasonography and histological structure of the skin:Relationship between collagen / elastin content and echogenicity

Background:High-frequency ultrasonography is used to non-invasively visualize the skin. However, few studies have focused on the association between ultrasound images and actual histology. Here we focused on the comparison of high-frequency ultrasound images and their actual histology using Cesarean scar tissue removed during delivery. Methods:This study included 12 pregnant women who provided a written informed consent. The ultrasound images of scars were captured prior to delivery using a high-frequency ultrasound device. Scars were sampled by an obstetrician, and collagen and elastin staining were performed on the samples. The amount of collagen or elastin was estimated by an intensity analysis using immunohistochemistry images. Results:Only low-echogenicity signals were observed in the scar tissue, although a tight structure was present. Echogenicity was significantly correlated with the elastin-positive area but not with the collagen-positive area. Conclusion:The echogenicity of ultrasound images appeared to be more closely associated with the amount of elastin than with the amount and/or density of collagen fibers.