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Testing an ultrasound machine 18 Jun

How to test-drive an ultrasound machine – for veterinarians

When I first began working with veterinary ultrasound, it was unheard of that a clinic would invest in an ultrasound machine without first receiving a demonstration in their practice. Nowadays, and particularly since Covid-19, in-person demonstrations are far less common, largely replaced by the dreaded loan system.

This works well from the point of view of very large medical companies. Often, their salespeople have large portfolios of a vast range of equipment, and cannot possibly be specialised enough to demonstrate an ultrasound scanner to anything greater than a very superficial level. Whether or not their ultrasound system is chosen is a bit of a lottery anyway, so participating in that lottery without the cost of paying someone for a day is definitely a good thing.

I, however, am definitely not a fan of the loan ultrasound machine from either a supplier’s perspective or a potential end-user’s. Sending a loan system puts the onus completely upon the veterinarian to figure out how to get the most out of that machine, which is actually the job of the ultrasound company (whether or not they are capable of doing it).

From the ultrasound company’s point of view, you have lost all control over that person’s experience with your system. If your client is not used to the layout of your particular system and cannot optimise their image, or even if you’re just unlucky and they scan a difficult patient, they won’t have a good experience with your machine – and you’re not there to do anything about it. From the buyer’s perspective, unless you are one of those rare human beings that enjoys discovering a new piece of technology for yourself, you have just been saddled with the job of learning a new piece of equipment inside out whilst simultaneously continuing with your actual job which is to diagnose and care for your patient. And if there’s one thing vets don’t need right now, it’s extra work.

Despite these criticisms, I cannot argue with the fact that delivering nationwide demonstrations is becoming increasingly costly and difficult, and the fact that they are no longer expected as standard comes as a huge relief. Saving on this huge cost allows clients to receive better pricing on ultrasound equipment, because the cost of doing business has been reduced. Our solution in this new environment has been to offer online demonstrations and walkthroughs – a sort of compromise to the loan machine scenario, whereby our customers purchase their machine with the knowledge that they can return it within 30 days if unhappy, and we schedule time together over Zoom to go over the machine in as much depth as they want. This has worked really well for us (nobody has changed their mind on a purchase yet!), but if you want to compare one of our systems with another make or model, or even if you have a preferred supplier that is not us (it happens!), what can you do?

 

How to test-drive an ultrasound machine on your own

If you find yourself taking delivery of a loan machine to test out, here are a few tips to get the most out of it – but also to discover any of its failings before you end up purchasing it.

1. Find the tissue harmonics button right away

Almost all machines over £3000 now come with tissue harmonic imaging (THI). In lower end systems, you will find that toggling this button on and off appears to do absolutely nothing. In higher end systems, it will make a big difference, so make sure you scan with it on and off to see which you prefer in different scenarios. If you spend the entire loan period scanning with it permanently on or permanently off, you will likely be doing the machine a huge disservice and may end up picking an inferior machine purely due to chance.

In the below canine pregnancy scan clip taken on the Acuson P500, tissue harmonics are initially turned off. This would lead you to believe that the nearfield image quality of the microconvex probe is poor. Hopefully, you can appreciate the difference it makes when THI is turned on!

 

In comparison, on this echocardiogram, THI makes little difference. If anything, the image is better at the beginning, when THI is turned off.

 

2. Don’t get hung up on numbers.

Someone may have told you that for cardiac scanning in cats you need a phased array probe that goes up to 9MHz. The ultrasound machine you used on your advanced imaging course may have had a microconvex probe that had a frequency range of 6-10MHz. Therefore, you want transducers that will cover these frequencies.

While frequency is important, do not see it as an absolute. 8MHz on a Siemens Acuson P500 will give you better images on a cat than 12MHz on a KX5600, so before you dismiss a scanner for not giving you the right frequency, look at the image. Is it of diagnostic quality? Can you see everything you need to see? How detailed is it? If you are testing it against another machine, compare the image, not the numbers.

 

3. Be unforgiving about Doppler

If you are buying a system with colour and spectral Doppler, you must be tough on it. Toggling it on and off over a blood vessel is not enough. If you will be performing abdominal scanning, use it in low flow conditions (e.g. kidneys) and faster flow (arteries). Check that colour flow is correctly coded inside the vessels with no ‘blooming’, and that it is sensitive enough to pick up areas of low flow. If you will be performing echocardiograms, stress testing the colour flow Doppler is even more important. Scan nervous cats, scan dogs with mitral valve disease, and check that the machine’s colour Doppler can keep up with the fast heart rate and provides you with genuinely useful information. Can you see the regurgitant jet on that dog, or do you only see flashes of colour?

So many ultrasound systems are marketed as colour Doppler systems, but in reality, their colour flow is clinically useless.

If you will be performing heart scans to a high level, be sure to also check tissue Doppler imaging (TDI). You will need this for your diastolic function assessments, as well as looking at systolic function of the right ventricle (S’). This is another major weakness of the vast majority of ultrasound machines sold for veterinary use at the moment.

The same principle applies to probe types, and being sure that you are testing like-for-like when comparing systems. In the below video, both the phased array and microconvex probes give excellent cardiac image quality on the P500:

 

When it comes to colour Doppler, however, the phased array probe performs well for echocardiography, but the microconvex probe’s colour Doppler performance is useless for this specialist application:

 

4. Look beyond imaging

Once you have judged image quality, think about what else you need from a scanner. Things like portability are immediately obvious, but factors which are often overlooked include ease of saving and transferring images. Are you happy exporting images and videos onto USB if you want to put them onto your practice system? Will you be using reporting software in the future that relies on images being transmitted in DICOM format? It is worth asking these questions now, because upgrading some systems to be able to save in DICOM can be costly, and the results suboptimal.

 

Summary

As always, our (admittedly biased) advice is always to speak to a specialist ultrasound company before choosing an ultrasound machine for your practice. Ask if they have anyone on their team who uses the machine you are interested in clinically themselves, and speak to that person. They will be able to give you all of the machine’s pros and cons, and while they will of course hope that you will choose to work with them, they are ultrasound professionals before anything: not career salespeople. Therefore, their primary motivation above all else will be their own reputation and lifelong career, and that is not something they will be willing to damage just to make a sale.

If you would like to speak with one of us at PortableUltrasoundMachines, please call us on 0203 972 2270, or email us here.

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