Ultrasonic characterization of the transmural structure of human scalp tissue

Interest in transcranial ultrasound has motivated numerous ultrasonic studies of the skull and brain; however, the ultrasonic properties of the scalp are relatively unknown. The goal of this study was to ultrasonically characterize the transmural structure of scalp tissue. Sixty-four formalin fixed specimens were prepared from four human donors and scanned in a water tank with a 25 MHz transducer to create parametric images of the speed of sound (SOS), frequency slope of attenuation (FSA), and integrated attenuation coefficient (IAC). Images revealed three distinct layers: a dermis/epidermislayer, a subcutaneous layer, and a connective tissue layer. A statistically significant difference was observed between all layers for all parameters in most cases. Exceptions were between the dermis/epidermis layer and the subcutaneous layer for FSA and between the subcutaneous layer and the connective tissue layer for SOS.