(Part 1 detailed recent advancements, specialty considerations, and the need for standardization.)

Machine selection

Plan to spend around $35-$50,000 or more for an ultrasound machine to do full body scanning. This may sound daunting at first, but I will explain what I have seen and learned over 25 years in the industry. We are not talking about FAST scanning here or quick sampling procedures. We are talking "If it's sick it needs a probe" clinical sonography, with every point in the abdomen or heart/chest imaged in all body types.

This is the mentality that is essential first and foremost before considering purchasing an ultrasound machine. If you don't adopt this mentality, then there is a much higher chance of being on the wrong end of a missed lesion.

The $35-$50k price range is "the best of the good enough" investment. This, of course, isn't a standalone $90k+ machine that images everything you want with little effort. If you can spend that amount, then you will enjoy becoming a da Vinci of sonography, and I will envy you. Since I have mostly scanned in mobile settings, my expertise lies primarily in the best mobile machine for your money. This $35-50k price range (probe configuration is the largest variable here), if priced conscientiously with respect to the quality and clinical support of the machine, should buy you image resolution to define curvilinear patterns and contrasting tissue presentations, adequate acoustic power to penetrate tissues, adequate probes with frequencies and resolutions for every presentation, work-flow optimization, optimized screen size and resolution, and consistent transmissibility of image sets in proper contained file size with minimal steps.

These factors vary greatly by manufacturer, so it is in your, and your sonographer's, best interests to test all these factors on multiple machines on a variety of patient sizes, conformations, and body scores with clinically tested presets for each setting.

Target a machine that gives you 7-12 cm of resolution depth (RD). Resolution depth is the imaging depth that allows diagnostic interpretation of a structure at a maximum depth. The RD will vary inherently on how clean and artifact free your near field is on the screen as well as probe frequency. But more importantly, acoustic power, the power pushed into the probe by the machine hardware, is the most important physical factor and is where the inherent price difference lies from machine to machine. Consistently depth resolution of 7-12 cm should be a target machine standard for small animal medicine. In our experience the 35-50k machines vary from 5-12 cm depth resolution, while the 25-35k machines typically give resolution to 5 or maybe 6 cm of depth, which means you have to push the body wall to the structure to make the distance 5 cm or less. Patient sedation and manual probe hand pressure techniques help with this but start with the machine that already gets you there because its guesswork in interpretation beyond 5 cm in these 5 cm RD machines and you risk missing a lesion.

If you aren't optimizing these factors, you risk:

• Missing lesions
• Struggling to find structures such as the common bile duct and right adrenal
• Missing steps in the telemedicine transmission
• Having to repeat transmission or encounter erroneously large files caused by software glitches that have not been addressed by the manufacturer or the distributor

All of these factors cause loss of time, which is inherent economic loss with every case. In telemedicine operations, we encounter these issues every day and work through them with our clients as we read from multiple types of machines with different manufacturers, machine capacities and software applications.

Therefore, it is best to prevent these issues by optimizing each of them as opposed to trying to cure the problems after you spent $20-$30k on a lesser machine marketed as "good enough" or "just as good." No matter how things are marketed, you get what you pay for or you may even overpay for lesser machines. If purchasing from a clinically oriented company you have clinical support, optimized and extensively tested presets for all body types and structures to image, instruction on which probe to use in each presentation, and a machine that lays out images on your report that represent you at a high level. Your imaging report is your calling card so do it right. Ensure your image is enhanced by your optimized machine purchase first with solid consistent acoustic power and resolution depth averaging in the 8+ cm range and not in 5 cm or you risk missing deeper lesions especially in animals over 50 pounds. If a salesperson tells you that a $20k machine is as good as a $30k machine, or a $30k is as good as a $40-$50k machine, then do this RD test on an 80-100 pound dog with machines head to head on your own, undisturbed and uninfluenced by a sales rep letting the machine physics speak for itself. The reality of ultrasound physics will allow for a better machine decision.

Dollars and sense

Consider this quick economic exercise over the five-to eight-year life of an ultrasound machine. If we just talk economics and painfully eliminate image quality for a moment, consider this simple calculation then have the tax break discussion with your accountant. At five ultrasound examinations/week at $350-$400 owner cost/scan, which is a minimal number that every facility should be doing clinically:

• A $15k machine is paid for in roughly three to four months
• A $35k machine is paid for in six months
• A $45k machine is paid for in eight to nine months

There is essentially no economic reason not to purchase the best possible machine you can to avoid the cost of missing a lesion. Just do the math, and high-quality imaging, footprint, and accuracy has a very small cost difference from a "just as good or good enough machine" that costs $25,000 or less in the end.

Be sure to do your true math calculating your average exam price per patient: your sonographer cost for 15 minutes to scan, your tech cost for holding the patient for those 15 minutes and five to 10 minutes to process and send the image set to telemedicine, your telemedicine average cost/report. Total these costs and subtract from your ultrasound charge to the owner.

You will realize $45k goes away very quickly and if you live by "if it's sick it needs a probe," the cost of purchase of a machine that is a representative core to your process is truly a non-factor. In other words, do clinical sonography correctly at the beginning and the economics are in your favor regardless, and will also grow and propagate fostering adjacent procedures in your facility that have their revenue streams as well. This is truly the healthy forest versus the healthy tree scenario.

Now imagine you miss a few lesions after buying a lesser machine because the budget given to you doesn't take the laws of physics and your clinical realities into consideration, especially in dogs over 50 pounds or on a cat pancreas that has poor resolution, and those lesions are seen elsewhere on second or third opinions. Confidence in your facility's clinical sonography drops rapidly as a result and you are now left with a $20-$30k cystocentesis machine or one limited to FAST scanning and loss of clinic confidence with internal or external referrals for ultrasound exams. This is the cost of missing a lesion.

Sonographer selection

The sonographer title behind the probe discussion comes up frequently in our clinical sonography circles. Do we need a specialist or veterinarian to perform solid consistent image acquisition? Remember image acquisition and image interpretation are two vastly different concepts.

Interpretation depends on optimal complete image acquisition, and many types of professionals in the veterinary field are fully capable of obtaining a complete sonogram image set if the protocols are well followed and if the drive and the ability to learn to perform an optimized and complete image set, whether normal or abnormal presentations are in play, is inherent in the mentality of the sonographer.

We, as interpreting specialists, see this image acquisition quality all the time every day over hundreds of cases. Optimal image sets come in from all types of sonographers with various professional titles as well as suboptimal image sets that need further support and instruction.

We have a long history of various results with GP sonographers and, of course, specialists performing ultrasound. I have seen veterinary technicians become elite imagers while some specialists, including radiologists, may only reach a certain functional level of imaging but never go get to elite imaging status. Of course, just the opposite is true as well where veterinarians and vet techs may never get to a consistent elite status but remain at a functional diagnostic one. Again, we are talking image acquisition here and not image interpretation.

However, the relatively new technician model works well in veterinary clinical sonography as it has in human for 30-plus years. The teaching/learning approach differs significantly with high-level imaging needing to be obtained in short time frames largely without the ancillary studies in physics and image optimization that the human medicine RDMS counterpart endures in his/her program. Regardless, our recent double-blinded study has shown technicians, veterinarians, and specialists can have similar image quality results when trained appropriately.⁴

Education/training

Choose the educational venue best for you, your workflow, and your goals. Which program will get you up to speed the fastest allowing you to image an abdomen or heart in 15 minutes or less without missing pathology? With practice, focus, and drive it really should not take you longer than 15 minutes and should be more in the 10-minute range for routine exams.

Consider your local mobile sonographer or best sonographer in your practice. At some point in the past, yours truly included, we all started somewhere wondering if the bladder had a stone when it was just hard stool in the colon superimposing upon an overdistended bladder. We have all made every mistake possible and have learned from every one of them if we were conscientious about each error.

This is one reason why I have written this article and continuously teach clinical sonography and discuss all the entities around the process. The sonographer reading this may benefit from all the errors I, and those that my anonymized colleagues have personally made over more than 25 years spanning from a young, novice veterinarian sonographer, a semi-seasoned specialist, and now as a seasoned specialist and educator. I have made the errors intrinsically inherent within my recommendations already, so you don't have to.

Telemedicine

It is extremely rare you will be scanning perfectly coming off a single educational seminar; there are vast levels of ability to interpret ultrasound image sets. Therefore, you need support by the company that interprets the images, and a scanning protocol that will work to your benefit. You should ask yourself as a clinical sonographer, and also ask your telemedicine company these questions:

• How is my image quality?
• What am I missing and why?
• Does my ultrasound report reflect the level of sonography I intend to practice?
• Am I learning from the report and the process?
• Is this process making me a better veterinarian or technician?
• Most of all, am I confident in the findings?

There are telemedicine services that only read still images and do not want videos, or limit them, because they take longer to interpret and occupy more bandwidth and storage space. However, video protocols exponentially include more information on all the organs and everything adjacent and in between them. Every three-second video contains about 120 still images. A complete SDEP protocol scan, or equivalent protocol, contains about 20-50 videos on average and a few still images for measurement. Doing that math and assuming image quality equal between still image sets and video-based protocols, then ask yourself these questions:

• Which set do you want your interpretation to come from?
• Which image set (still images vs. video) do you want your clinical choice for that patient to depend upon?
• Do you prefer to risk your cost of missing a lesion on 30-50 still images or on 30-50 properly placed video clips (i.e., 3600-4800 still image equivalent)?

Moreover, the video employed protocol, such as SDEP or equivalent is a much more fluid scan and saves tons of time as opposed to traditional stop-save, move-image-to-next-position type protocols that force you to get every still image right in line as opposed to retrieving the perfect still image from a video clip passing through the organ.

In regard to interpreting specialists available in veterinary medicine, the recent ACVR/EVDI standardization states, "Interpretation at the time of the examination being performed by a board-certified veterinary radiologist is therefore considered to be the gold standard." ¹

Sonographers and referring veterinarians will find, in reality, that this radiologist specific focus is not and will never be possible owing to the lack of radiologists available to read sonograms compared to the increasingly vast number of ultrasound image sets being created and sent to telemedicine companies or those for in-house review.

The good thing is many American Veterinary Medical Association recognized boarded specialists who have many years of experience in clinical sonography are available to interpret image sets with an approach and emphasis on their specialty such as ACVIM, ABVP, VECCS as well as other accredited specialties that have clinical sonography incorporated into their functional disciplines and core clinical experience. With this specialist spectrum of availability, the sonographer and referring clinician can select which type of interpretation to have: 1) a radiologist perspective, or that of internal medicine, practitioner internal medicine and surgical approach, or 2) emergency critical care approach with many years of preparation behind the read.

Machine specification considerations

Screen size and resolution: Take into consideration screen resolution and screen size. You should position yourself about an arm's length away from the screen. If you are trained to find adrenal glands and you are testing out a machine, a feline or canine adrenal should jump on the screen.

You should not have to squint to look at it. Consider 15–18-inch monitor screens and at least 1920 x 1080 resolution if possible. Every little technological factor in your favor adds up in image quality, and these two factors very often go underconsidered in purchases.

Ultrasound knobology/workflow

I personally despise touch screens as it is too easy to make errors, and digital workflow is tedious and frustrating in my hands. When I can feel a keyboard, I can move across knobology workflows faster. Maybe you like touch screens and your brain and fingers work differently than mine, which is fine. Do what works best for you. But ask yourself, how much time does the knobology of the machine take you? Compare machines on knobology workflow. This is an often-overlooked concept but one that is inherent in the time elapsed on every scan. How many steps does it take you to get through your case?

There is a vast difference here by different machine producers from very intuitive and user friendly where you will take three to four steps to get to the end of a case from a knobology standpoint to others that will take the scenic route to get there with 10 or 12 steps and touch screens that are not consistent.

When there is poorly designed knobology, you feel like your fingers are doing a bad ballroom or line dance where you are always a step or two behind and bumping into someone or stepping on toes. Personal experience in both sonography and short-lived ballroom and line dancing experience aside, all I can say is poor knobology workflows translate into time lost and frustration gained.

Image transmission: Given that image quality is paramount, you must spend adequately to work with a machine that is going to be viable day in and day out, thin ferret to overweight Rottweiler, abdomen to heart to thyroid to stifle cruciate sonogram.

You want a machine capable of high resolution and has a rapid workflow that can move a 30-50 video case around the internet at 500 MB and not 1 GB, or 2 GB, or 3 GB. What happens when you try to move a 1 GB, 2 GB, 3 GB file around the internet from your ultrasound machine? It blocks up, your bandwidth cannot keep up with it, your connectivity drops off, you may have to resend it, it will take time to send, and you must double check it, which all eats up time and delays the report.

Then the telemedicine specialist will be perturbed because of the time involved to download it on their end to be able to see it and manipulate it. So, ensure the machine you are purchasing can move a large set of videos across the internet readily, otherwise you will be disappointed and frustrated because now that you bought that machine, you have to work with it; if its inherent workflow is poor, you will pay the price over time.

What is that time and frustration worth to you? We deal with this every day in the telemedicine world, having to employ a technician to specifically work with clients on this issue from a variety of machines; this is why we created protocol standards to avoid these pitfalls on our end. But I relate this to you to help avoid these frustrating tech and doctor sonographer time-consuming issues on your consumer sonographer side of the workflow equation.

Missing lesions: If we were just dealing with a standard extensive pancreatitis, cholangiohepatitis, gastroenteritis, or a global mass, but no obvious metastatic lesions to the liver, then the lesser machine can likely cover these areas adequately in a 40–50-pound dog or smaller. However, if I were to go through my team's telemedicine archives these global pathologies are only one small aliquot of the pathology that we see coming across the probe every day. The more subtle presentations are just as frequent and even more frequently missed. Therefore, you can do the lesion frequency math and if those more subtle lesions are not coming across your probe and screen, then I assure you that you are missing lesions and what is the cost of that?

If we consider the pathologies that enter our veterinary facilities on a daily basis, and if we focus directly on the ultrasound machine we choose and utilize day in and day out, and the instructional process involved in clinical sonography, then we have to take image quality first and foremost into consideration to see the subtle and global pathologies that are present in every given case, or be confident we performed a complete lesion free sonogram when we encounter a negative scan.

For example, a cat with pancreatitis can have a 0.5-1.0-cm lesion responsible for its presentation, a lesion that is subtle and isoechoic and unrecognizable on a lower resolution, and hypoechoic and recognizable on a higher resolution image, especially if video is employed to visualize the dynamic image contrast in the tissue before and after the lesion as we scan dynamically through the organ. If you do NOT use a higher resolution and video, you will often miss such a lesion and the diagnosis will go unfound or become presumptive.

A common bile duct tumor, a common pathology in older cats, is often isoechoic to the surrounding liver tissue and can be easily missed, as can a common bile duct calculus or similar subtle pathology we see daily as professional clinical sonographers.

Other examples include gastric ulcers, phrenic vein invasion from an adrenal nodule/mass, flattened small adrenals typical of Addison's disease, or the ubiquitous pelvic urethral tumor that blends in with pelvic fat. These are just a few examples of crucial high-resolution lesions and common pathologies that we see in high volume sonography and in the telemedicine world. These lesions, and many like them, represent a sentinel to what walks through the clinic door.

Therefore, if you are not imaging these types of lesions on a regular basis, then more work needs to be done as these disease processes are out there and are being missed. I always tell everyone to start from Day 1 in your clinical sonography curve to capture high-end views. Even if you do not recognize the smaller structures, just capture them using the larger organs as target focal points of your video sweep. Then send the image set to telemedicine where specialists recognize the smaller structures and subtle changes just as you would recognize a kidney, liver, or spleen.

However, if the common bile duct, pylorus, deep pelvic urethra, and ileocecal junction aren't captured in video loops, then both the sonographer and telemedicine or overreading specialist will not see them either.

This is where the image optimization discussion above raises its necessary head in the process. The more you send to telemedicine early in your curve, the more you learn and recognize, the less you need to send in the long term. But you will then possess a healthy interpretive learning curve along the way.

In sum, the sonographer and overreading specialist must work in synchrony symbiotically with video loops capturing all views of large and small structures with redundancy and multiple angles which are essential to this effective professional collaboration to avoid the cost of missing a lesion.

Over-reading the situation—the specialist's perspective

Now to examine the telemedicine specialist, or in-house over reader, side of the equation. Take that 5-mm common bile duct (CBD) carcinoma as an example. If you have a lower-end machine and you are saving still images and not video into and out of the region, you will miss that lesion unless you know to specifically image that CBD to the duodenal papilla.

My telemedicine team, as a rule, never makes a definitive diagnosis on a still image. We use still images for measurements, but diagnosis is made based on video so we can see the tissue going onto and out of a lesion, and the capsules going around the lesion. Therefore, you must have a machine that can process videos well; usually a three-second DICOM loop is adequate to cover as much tissue in an organ system as possible. In addition, you must have an ultrasound machine processor that can keep up with that speed and acoustic power, and correct probe frequency to penetrate deep enough into the larger animals where that lesion may be. In that case, a three-second video is evaluating 120 still images as opposed to a properly or improperly positioned still image to make a diagnosis, which is the focal point on what you are going to do with that patient.

A video in the portal hilus will image the common bile duct every time. Utilizing video capture enables the specialist to amplify the image, investigate the common bile duct, and make sure there is not a 5-mm common bile duct tumor, calculus or mucoduct, which are common findings we see sonographically. However, if the correct video is not there, both sonographer and overreading specialist encounter the cost of missing that lesion.

Think of the political sequence that happens from that point of missing a lesion. Think of the pet's clinical concern, the pet owner conversations involved, the conversations and relationships with colleagues in and out of your facility, and the time and financial expense up to that point in the case workup without a correct and definitive diagnosis. Then, consider the second opinion colleague who images and diagnoses the missed lesion and then the repetitive above issues that occur after the lesion has been found down the road at another facility.

This is the reality I am trying to help you avoid when considering ultrasound purchase, training, support, and telemedicine. I have been on both sides of this equation, as you can imagine, and have consulted endless colleagues through these scenarios from both sides, as well.

Elevate your clinical sonography process to optimize the first scan so further imaging confirms what the first scan showed as opposed to evidencing your cost of missing a lesion conundrum. I would hope all colleagues support each other professionally on both side of this issue which is the strict policy in my circles. None of us were born perfect clinical sonographers and we all miss lesions and diagnoses. However, why not maximize the ability to image all lesions in the cavity scanned and minimize your cost of missing the lesion the first time?

What to ask, consider

Here are some quick questions to ask yourself and ponder when you are about to evaluate your current machine, or purchase new one, and examine your clinical sonography and telemedicine workflow:

1. Is your preset correct and are you using the right probe? This should be taught to you by the support people with the distributor where you purchased.
2. Is the preset optimized for that sized patient? It should be the highest frequency with adequate depth penetration to readily image the whole organ or region.
3. Have the various presets and respective probes been tested over many patients before being implemented? This should be a support mechanism from your distributor.
4. Is your monitor sized at least 15-18"?
5. Is your screen resolution at least 1920 x 1080?
6. Is the processer strong enough to move through the adrenal gland approaches in a 3-second video (or faster) without pixelation?
7. What is my resolution depth (RD) average during the scan. Shoot for 8 cm or greater where the structures are easy on the eye to interpret at that depth if the near field is artifact free.
8. Is the acoustic power strong enough with the correct low frequency probe to image cleanly the intercostal liver of a 140-pound Newfoundland?
9. How does the software look? There is software that does not allow you to see the curvilinear patterns of tissue that are essential to not missing the lesions cited above in this article. If the software does not allow for adequate contrast, you won't see the inflammation in the neck of the gallbladder mucocele as the shades of grey and white just all blend in.

This interpretation, or lack of it, defines the pet as an urgent surgical gall bladder patient or not. If the image is too soft and hazy you cannot distinguish contrast from one organ to the next, or adrenal from the surrounding fat, or the common bile duct from surrounding parenchyma or a pancreatic capsule from surrounding mesentery as everything blends together. Is the color flow or power Doppler weak and easily distorts owing to acoustic interference or tense patient abdomen?

These are factors that are crucial, so I like to use the adrenal gland as my sentinel image. You can use the common bile duct, pelvic urethra, ileocecal lymph nodes, or use all of them, but test, test, test machine against machine in a variety of patients, conformations, body scores, and cavities.

Every machine should image a cat or small dog or even an overweight beagle well with adrenals and other organs jumping on the screen. But can the machine image 50-100-pound patients consistently? If not, you will have the cost of missing a lesion in those patients even if your imaging technique is solid. It's just physics, technology, and clinical support behind the machine that you are paying for assuming the machine is priced appropriately for its capacity.

10. What is the cost of staff time? To review, imagine if your time is not optimized with the use of the machine as a clinical sonographer.

• Are your workflow steps minimized or are you doing a bad ballroom dance with the machine workflow?
• Is your transmissibility of a case streamlined in case size and steps to send it or is the file transmission hanging up in the process?
• What is the cost of your technician's time in patient setup, restraint, image transmission and case submission (which are highly recommended if you are trying to optimize your time) with you as the veterinarian sonographer?
• Or what is the cost of your technician's time if he/she is doing the scanning? Technicians can become optimal sonographers and we have seen that and fostered repeatedly.⁴

Quick Ultrasound Machine Purchase Checklist

Do your ultrasound economics. Example: Ultrasound exam cost to owner – sonographer/tech/telemedicine costs X scans/month x 9 months. For example, $400 exam fee to Pet Owner-$150 operational costs= $250 net revenue x 20 scans/month = $5000 x 9 months = $45000. This is based on a 1 doctor practice so imagine if a 3 or 5 doctor practice does this calculation. Factor in education costs as well if needed. Do the math first, then select machine price point. Get the best machine you can to be ahead of the learning and professional clinical sonography curve Clinical sonographer selection regarding desire, time allotment, focus, dedication, and longevity of employment Education type and facility. On site vs. live virtual or downloadable Machine Cost: Evaluate $35-50k+ category Screen size 15-18" or larger and resolution 1920 x 1080 or better Software appearance. Can you readily distinguish adjacent tissues from one another? Far field image quality at 6-12 cm depth Does the image pixelate on fast video sweeps? Image quality on all body types, especially thin cats, cat hearts, and overweight large breeds. Check your RD. Knobology & image transmission workflow. How efficient is it? Ensure simple easy short pathways in scanning, transmission, and file size. Count the steps from image set acquisition to transmission between machines. How are you supported during this process by the distributor before and after the sale and 5-8 years later? Seek out references not provided by the distributor. For better objectivity, utilize social media by asking a number of opinions to vet out the company you want to work with. Veterinary facility culture: "If its sick it needs a probe." Accept no less and demonstrate the results of this concept and culture with your staff and shelter pets first and go from there. Enjoy your art of veterinary medicine and have fun knowing you checked the boxes!

 

In sum, when buying an ultrasound machine (concepts apply to CT or DR system, as well) what is the cost of missing a lesion? Think about that. Think about what happens when you miss a lesion, and you are not correct on your first opinion. That does not bode well for you as a professional, for the facility where you work, or for your reputation as a clinical sonographer.

Most of all, it does not bode well for the patient, which is the opposite outcome we desire with respect to the reason we all went into the veterinary profession in the first place.

Evaluate the cost of missing the lesion with respect to your patient, your pet owner client, your time, your team's time, your image and report footprint, your reputation, and most of all how the cost of missing a lesion ultimately affects your art of veterinary medicine that you and your team have so painstakingly dedicated yourselves to all these years. Then look at these steps and knock off this checklist when looking at machines.

Eric Lindquist, DMV, DABVP, Cert. IVUSS completed his undergraduate degree in zoology at Humboldt State University, and his veterinary degree at the University of Bologna in Italy. Dr. Lindquist is a boarded American Board of Veterinary Practitioners (Canine and Feline Practice) and was also a three-time president for the International Veterinary Ultrasound Society. He founded SonoPath in 2007, which he expanded into multiple mobile sonography operations, leading a team of over 15 boarded specialists who provide Educational Teleconsultation services and lectures worldwide on clinical sonography. SonoPath headquarters and Veterinary Education Center is based in Andover, NJ. Dr. Lindquist is the developer and founder of the trademarked SDEP abdominal, cardiac ultrasound protocols first published in 2019 at the European Veterinary Diagnostic Imaging annual meeting in Basel, Switzerland.

References/Resources

1. Seiler GS, Cohen EB, d'Anjou M-A, et.al. ACVR and ECVDI Consensus statement for the Standardization of the Abdominal Ultrasound Examination. Vet Radiol Ultrasound. 2022;1-14.
2. Lindquist E, Lobetti R, McFadden D. proposed standardized procedure for abdominal sonograms in dogs and cats: Sonographic Diagnostic Efficiency Protocol (SDEP®). Abstract presented at EVDI Congress 2019; August 21-24; Basel, Switzerland. Abstract published Vet Radiol Ultrasound. 2019 Nov.
3. Lindquist E, et al. Clinical parameters in dogs with sonographically diagnosed surgical biliary disease. Abstract presented at ECVIM Conference 2009; Sept 8-10; Porto, Portugal.
4. Lindquist E, Lobetti R, McFadden D, et al. Abdominal ultrasound image quality is comparable among veterinary sonographers with varying levels of expertise for healthy canine and feline patients. Vet Radiol Ultrasound. Nov/Dec 2021; 62, 1-6. Digital, 705-710.