In an ACTA Informatica Medica article, a research team, including lead author Aladin Carovac with the University of Sarajevo, laid out the basics of ultrasound and its application in medicine.

An ultrasound device, in essence, is a transducer, a pulse generator, amplifiers, processors and a system for display. Medical professionals use ultrasound devices in abdominal, obstetric, cardiac, gynecological, cerebrovascular and urological cases among others.

Sonographic scanners operate at frequencies between 2 and 18 megahertz which is hundreds of times higher than the limit of human hearing. The higher the frequency, the smaller the wavelength, which means greater detail for the sonogram image. Ultrasonography is an imaging technique that creates images of body structures like tendons, muscles, joints, vessels and various internal organs.

Four different modes are used in medical imaging. These include:

A-mode: A-mode is the simplest type of ultrasound. A single transducer scans a line through the body with the echoes plotted on screen as a function of depth. Therapeutic ultrasound aimed at a specific tumor or calculus is also A-mode, to allow for pinpoint accurate focus of the destructive wave energy.

B-mode: In B-mode ultrasound, a linear array of transducers simultaneously scans a plane through the body that can be viewed as a two-dimensional image on screen.

M-mode: M stands for motion. In m-mode a rapid sequence of B-mode scans whose images follow each other in sequence on screen enables doctors to see and measure range of motion, as the organ boundaries that produce reflections move relative to the probe.

Doppler mode: This mode makes use of the Doppler Effect in measuring and visualizing blood flow. Sonography can be enhanced with Doppler measurements, which employ the Doppler effect to assess whether structures (usually blood) are moving towards or away from the probe, and its relative velocity.

Carovac and team wrote that ultrasonic waves are waves of frequency above the decibel human ears can distinguish. They went on to write that the most important parameters medical professionals consider about the wave are:
• Wavelength
• Frequency
• Velocity
• Intensity

The team noted a few problems in the use of ultrasonic devices. Accuracy and detail in the ultrasound device is often dependent on lateral (sideways) and axial (depth) resolution.

For children, the ultrasound frequency is between 5 and 7 MHz while adults are scanned between 3 and 5 MHz. Sonographers work to reduce the sensitivity of their scanning devices so that the lateral resolution remains strong, resulting in better images.