Veterinary ultrasonography: Shaving the cat was the easy part
Eli Cohen, DVM, DACVR, is a clinical assistant professor of radiology at North Carolina State Universitys College of Veterinary Medicine and co-owner of Dragonfly Imaging, PLLC.
You've got ultrasound questions. We've got answers. Consider these cat-veats to maximize your machine.
"My new look leaves me a little cold." (Shutterstock)Ready for an ultrasound machine? The key to figuring out its utility in your veterinary practice is all about how you want to use this modality, says Eli Cohen, DVM, DACVR, a clinical assistant professor of radiology at North Carolina State University's College of Veterinary Medicine and co-owner of Dragonfly Imaging. At a recent CVC, we sat down with him for a quick Q&A.
Q. For those practices that do not have an ultrasound machine, why should they seriously consider it?
A. Ultrasound is a noninvasive modality. It doesn't hurt the patient. There's no radiation. Once you have the machine and probes, it's pretty cheap to use. I think the main thing is considering how you want to use ultrasound in your practice. Are you going to use it for cystocentesis? Are you going to use it for point-of-care ultrasound and FAST (focused assessment with sonography for trauma) scanning, or do you want to be doing full abdominal and thoracic scans and echocardiographic exams, etc.? From a business standpoint, it really depends if you're getting a $30,000 machine with one or two probes/transducers or a $200,000 high-end machine with multiple probes/transducers, what you're going to be using it for, and what you are going to be charging for those services. For a typical machine with one or two probes/transducers that most general practitioners would use, from both a business standpoint and the standpoint of raising the standard of care in the practice, ultrasound is a great modality to have on hand. It can really expedite the process of sorting out what's going on with your patients (Figures 1A-1C).
Figures 1A-1C: Left lateral (Figure 1A) and ventrodorsal (Figure 1B) abdominal radiographs along with the corresponding ultrasound image (Figure 1C) of a radiolucent jejunal foreign body (arrowheads) causing mechanical ileus in a dog. This foreign body was a plastic squeaker toy. This can be a difficult radiographic diagnosis, because if a foreign body remains gas-filled it can mimic intestinal gas. An internal fluid line (asterisk) is visible on the ultrasound image within the squeaker toy. (All photos courtesy of Dr. Eli Cohen)
A live ultrasound recording showing the squeaker toy, courtesy of Dr. Eli Cohen.
Hear it straight from Dr. Cohen here, including how it can help quickly determine a prognosis when triaging patients:
Q. There can be a bit of a steep learning curve. How do you make that judgment of whether you're really going to use it? What recommendations do you have for the education afterward to make sure that you're using it?
A. What I usually tell the people when I do CE with general practitioners or non-radiologist specialists is that it takes 10,000 hours to become an expert in something. All our residents do all day when they're on ultrasound is scan, so they can do 20 high-quality scans in a day. That volume of scanning with immediate feedback really accelerates the learning process. So you have to start with what you want to use this for. Do you want to be using this for safer cystocenteses and point-of-care/FAST scanning, or do you want to be doing full abdomen scans? Point-of-care and FAST scanning are skills that can be achieved relatively quickly with minimal training, but being able to do high-quality full abdominal scans isn't something that can be tackled with a single day of training. If you want to be doing full abdomen scans, then weekend CE or week-long CE courses are terrific. But if you put that up against 10,000 hours, that's just one component of becoming proficient.
In addition to CE courses, I think it's a really good idea to develop a relationship with a teleradiology company or radiologist who will help you improve your scanning. Keep in mind that for most companies, when you send them ultrasound images, they're going to be interpreting the images for clinical information. Their job is not really to make you a better scanner, and some of that is hard to do from a distance. Having more of a personal connection with one of those companies or a radiologist that can help you optimize your images and improve your scanning in addition to image interpretation is something I recommend for people that are interested in becoming good sonographers. Once a year, consider having somebody out on site for a couple days-have that be part of the business plan if you're going to buy an ultrasound machine. Immediate feedback on what you are doing is really important for the learning process. You can be scanning the wrong way or not identifying lesions for a long time without knowing it. I think having someone out on site periodically to augment CE courses and fine tune your scanning is a smart plan.
An ultrasonogram showing a splenic mass and peritoneal effusion, courtesy of Dr. Eli Cohen.
Hear more from Dr. Cohen here:
Q. Do you think there is any role for the veterinary technician to step in for some of the scanning?
A. Yes, I do, and I work with a veterinary technician who is very skilled sonographer. The main difference is knowledge of pathophysiology and when imaging findings should prompt other specific questions related to that patient's illness script. It's not only about learning to locate the organs and acquiring optimized standardized images for interpretation. Those things are important, but it's also about knowing what's the next question to ask. For example, if the liver is small and irregularly marginated, I need to remember to go do a portal velocity and assess for the presence of portal hypertension. These extra components, which are prompted by the clinical picture and may not be part of standard image acquisition, can have a big impact on patient management and prognosis. At the end of the day, ultrasound is a “real-time” modality that is highly operator-dependent. Once the images are made and sent, whoever is interpreting them is at the mercy of whoever has acquired the images. To that end, it's vital that whatever images or video clips are acquired for interpretation are representative of both normal and abnormal findings for that particular patient (Figure 2).
Figure 2: An ultrasound image of a dog's abdomen with a splenic mass and hemoabdomen. An irregular echogenic mass (arrowheads) is present arising from the ventral extremity, or tail, of the spleen. Power Doppler demonstrates a blood vessel crossing from the more normal-appearing splenic parenchyma into the mass (arrow) confirming splenic origin. There is a large volume of echogenic peritoneal effusion (asterisks).
Hear more from Dr. Cohen here: