Physical Principles and Image Creation

While in order to read an ultrasonic image correctly it is necessary to understand how ultrasounds interact with biological tissues and how the ultrasound system constructs the image, this is even more true when studying the thorax due to pulmonary air and the bones of the ribcage that alter the propagation of ultrasounds. For these reasons, this initial chapter, oriented toward practical applications, simply discusses the physical principles that preside over the creation of an ultrasonic image. In particular, it explores how the phenomena of reflection, refraction, scattering, and diffuse reflection affect the creation of thoracic ultrasound images, thus including important notions for resolving interpretive problems and for optimizing equipment settings. The role of these phenomena in generating essential semeiological signs in thoracic ultrasounds, and numerous artefacts will be examined and explored in-depth in the following chapters. Finally, in a simple but exhaustive way, the fundamental aspects of the study of blood flow, both with Doppler applications and through the use of second-generation contrasting mediums, will be addressed.