Fundamentals Of Ultrasound Studies

OVERVIEW

This page is dedicated to covering the fundamental aspects of how ultrasound imaging works.

Ultrasound technology is commonly used within the clinics. Before diving too deep into all of the specific ultrasound studies that can be ordered...it is worthwhile learning the basics of this imagine modality! (source)
Ultrasound technology is commonly used within the clinics. Before diving too deep into all of the specific ultrasound studies that can be ordered…it is worthwhile learning the basics of this imagine modality! (source)
WHAT ARE THE BASIC COMPONENTS OF AN ULTRASOUND MACHINE

While there are may different types of ultrasound machines, they all (more or less) share certain common shared elements. Lets take a moment to cover these now:

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The core elements of an ultrasound machine involve a probe and monitor (source)

The probe is responsible for generating AND detecting sound waves.

The monitor is responsible for rendering an image of the structures that are being “probed”.

HOW DOES IT WORK?

Fundamentally ultrasound imaging works by utilizing sounds waves to visualize structures within the body. A transducer (i.e. the ultrasound probe) will emit sound waves, and will also record echoing waves that bounce back towards it off of structures. The image that is generated is combination of sound waves that are reflected, absorbed, and refracted.

It is important to appreciate that ultrasound not only produces sound waves, but records the ones waves that are reflected back towards the probe (source)
It is important to appreciate that ultrasound not only produces sound waves, but records the ones waves that are reflected back towards the probe (source)

In looking at a real ultrasound image it is important to appreciate exactly how the detection of sound waves translates into the generated picture that is visualized. The probe that is used for ultrasound can detect the amount of signal that is reflected from internal structures (which can evaluate the composition of the object), as well as the amount of time that it takes for these waves to be reflected (which can assess for the distance of the object in question).

The colors shown on the ultrasound (as well as their position on the screen) will tell the viewer different information (source)
The colors shown on the ultrasound (as well as their position on the screen) will tell the viewer different information (source)

Here are a few basic components to keep in mind when looking at an ultrasound image: 

  • Lighter colors (white/echogenic/hyperechoic) represent structures that have reflected the produced sound waves back to the probe (the more a structure reflects sound waves the lighter it will appear in the image). Bones will reflect sound waves well and appear white.
  • Darker colors (black/hypoechoic/anechoic) represent structures that have absorbed/do not reflect the produced sound waves (the less a structure reflects sound waves the darker it will appear on the image). Fluid does not reflect sound waves and will appear black.
  • The top of the screen (anterior) shows structures that are closer to the probe (these are areas in which it takes less time for sound waves to reflect back to the probe).
  • The bottom of the screen (posterior) shows structures that are further away from the probe (these are areas that take the most time for the sound waves to reflect back to the probe)
WHAT DOES DOPPLER ULTRASOUND REFER TO?

Without getting into too much detail, the idea of Doppler ultrasound is actually (at its core) quite simple. Given the nature of the doppler effect, doppler ultrasound is useful because it can actually determine the speed at which objects that are being evaluated are moving.

It is important not to get lost in the details. Doppler ultrasound evaluates the changes in frequency between the transmitted and reflected sound wave frequencies. This (as is the case with the Doppler effect) can help determine the direction the object is moving, as well as its speed (source)
It is important not to get lost in the details. Doppler ultrasound evaluates the changes in frequency between the transmitted and reflected sound wave frequencies. This (as is the case with the Doppler effect) can help determine the direction the object is moving, as well as its speed (source)

Why do we care about doppler ultrasound in medicine? Really in the realm of the medical field doppler ultrasound becomes very useful went evaluating for the presence of blood flow (given that pumping blood in arteries really is what moves the most in the body). Doppler ultrasound can be combined with traditional ultrasound imaging (this is often called Duplex ultrasonography) to provide information on both structure and blood flow within areas of the body.

I this renal artery duplex ultrasound, both the structure of the renal artery can be visualized, as well as the blood flow through the vessel (the bright color represents blood flow, source)
I this renal artery duplex ultrasound, both the structure of the renal artery can be visualized, as well as the blood flow through the vessel (the bright color represents blood flow, source)
OPTIMIZING YOUR UTILIZATION OF ULTRASOUND

This guide was created to go into further detail about how to adjust ultrasound machine settings to that the user can optimize the quality of images that they can acquire from this modality.

 

Page Updated: 08.15.2016