Ultrasound Technique

Technique

Ultrasound uses sound waves. They are reflected, deflected or absorbed in the body. The reflected sound waves produce the ultrasound image. The more sound waves are reflected, the more hyperechogenic (= whiter) the tissue is imaged. With reduced reflection, the image will be more hypoechogenic, and anechogenic if there is no reflection (= black). 
Both the speed of sound through the tissue and tissue density impact the quality of the ultrasound image. High-density tissue generates multiple echo reflections (e.g. bone/calcareous structures), producing hyperechogenic images. Fluid reflects no sound waves and therefore is anechogenic (= black). Soft tissue (e.g. organs) is somewhere between hyperechogenic and anechogenic. Isoechogenic is when the tissue has the same echogenicity as the surrounding tissue (fig. 4/5).