Ultrasound scanning is an important clinical tool in providing images of internal fetal anatomy. It is also called sonography because it uses high-frequency sound waves to produce images of slices through the body.
A transducer or probe which emits ultrasound waves is placed on the skin after coating it with a thin layer of conductive gel, to make sure the waves pass smoothly through the skin.
The emitted ultrasound waves are reflected by different structures encountered by the waves. The strength of the reflected waves, and the time they take to return, form the basis for interpreting the information into a visible image.
Ultrasonography is an imaging technology that uses high-frequency sound waves to characterize tissue. It is a useful and flexible modality in medical imaging, and often provides an additional or unique characterization of tissues, compared with other modalities such as conventional radiography or CT.