Echo basics: Machines and Probes • LITFL • Radiology Library

We can do transthoracic echocardiography (TTE) pretty much anywhere. This has resulted in a range of different types of machines to reflect this. Here are the pros and cons of 3 types of machines, how to identify the different types of probes, and what each type of probe is used for.

Full-size, high-end echocardiography machines

Full-size echocardiography machines are great for complex echo techniques, and tend to be found in an outpatient environment. They are stationary.

Pros

Permanently wire to the archive, which makes it much easier to save our studies.
They provide really good quality images.

Cons

Heavy
Difficult to steer
Tends to be expensive

Laptop-sized echocardiography machines

These are great for going on the wards, using in your emergency department, or taking them out to a community clinic, because they’re so portable.

Pros

Moderate cost
Reasonable functionality
Improving functionality e.g 3D

Cons

Tend not to be wired to the archive, so you have to actively remember to save your studies at a later date.
The image quality not the best.

Handheld echo machines

Handheld echo machines are changing the character of echocardiography. They’re about the size of a mobile phone. Most can do imaging, and some can do colour.

Pros

Highly portable
Affordable

Cons

Limited functionality
Storage is limited
Difficult to use, especially for the novice

What are the different types of probes?

Now let’s think about the probes. It could be that your machine just has one probe hanging on it, and that’s easy. You know what to do.

But there could be several, so you need to be able to recognize the probe you’re going to use. Here are 4 types of probes:

Illustration of 4 types of echocardiography probes (cardiac ultrasound, vascular imaging, abdominal ultrasound, and a pencil probe)

Cardiac ultrasound probes

The bit that you place on the patient’s chest is quite small on a cardiac probe, so it fits between the patient’s ribs. On a paediatric probe, it’ll be even smaller.

Pencil probes

These probes are long and skinny, with a circular end. We use this type of probe for standalone continuous wave Doppler.

Vascular imaging probes

If you see a probe with a long, skinny footprint, it’s probably going to be used for vascular imaging.

Abdominal ultrasound probes

And if you see a probe with a big footprint and a curved shape to it, that’s probably going to be used for abdominal ultrasound.

What frequency is used for different probes?

You need to use the right frequency of probe for what you’re going to use, and for adult practice, that’s going to be between 2 and 4 MHz. For paediatrics, it’ll be higher, at about 7.

This is an edited excerpt from the Medmastery course Echocardiography Essentials by Helen Rimington, PhD. Acknowledgement and attribution to Medmastery for providing course transcripts.

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