Renal function analysis: A study in contrast agents

July 21, 2016
Anthony Pease, DVM, MS, DACVR

Veterinary radiologist Dr. Anthony Pease explains why contrast agents are a quick, easy way to examine the urinary tract

A ventrodorsal radiograph of a 9-month-old puppy dribbling urine. Note the slightly larger right ureter compared to the left (arrow) and the caudal insertion of the ureter into the urethra indicating an ectopic ureter and the cause for the clinical signs. (Radiograph courtesy of Dr. Pease.)


'I can't pay for all these diagnostics!'

Situation: The pet needs help, the client is short on money, and your veterinary team absolutely needs the diagnostics, such as contrast radiography, to decide on treatment. Third-party payment plans or in-house payment plan: What's the way to go?

Watch the fees ...

"Some credit providers charge the hospitals a very high fee. If a client chooses a zero interest loan for 24 months, for example, I've seen client credit providers charge as much as 14 percent to my hospital. I limit client options to a maximum 4.9 percent fee. That's more than most credit companies charge, but still manageable." - Jeff Rothstein, DVM, MBA, owner, Michigan-based Progressive Pet Animals

The fees are worth it ...

"Even if the cost to the practice is higher than with typical credit cards, the profit margin on additional services can be huge. This is, of course, assuming clients who take advantage of these payment options are filling holes in a practice's appointment schedule and aren't using up spots from folks paying cash or using regular consumer credit cards. You don't want to replace revenue that comes at a lower cost with revenue that comes at a higher cost but if, overall, using these plans brings more revenue in the door it can be very beneficial." - Karen Felsted, CPA, MS, DVM, CVPM, consultant, PantheraT Consulting

We do it all …

“In addition to accepting CareCredit and now the H3 WellnessPlus card from Veterinary Credit Plans, we use PaymentBanc because they call clients when scheduled payments fail. We still have a few in-house payment plans-just promissory notes for clients who didn't qualify for anything else. We offer emergency care, so we have our share of these.”- Merja Reynolds, CVT, director of systems and operations, 1st Pet Veterinary Centers in Chandler, Arizona

It's not magic-it's just another option

“In-house or third-party: One's not better than the other. They all have their role in helping veterinarians practice without focusing on the money as much. It's also all helpful for team members, who can tell clients we can lend something to you, rather than doing it behind the boss's back.”- Greg O'Brien, founder, practice management and investment company O'Brien Veterinary Management, with locations in Illinois and Indiana

Challenge: You need a speedy way to examine a patient's urinary system that requires less skill and training than ultrasound.

Solution: Contrast agents!

Why: Because contrast agents are excreted by the kidneys, they provide a way to functionally see whether or not the kidneys are working. For example, if the kidneys are experiencing anuric renal failure, the contrast medium will not be excreted through the ureters and will accumulate in the kidneys.

Contrast agents can help diagnose conditions such as ruptured ureters, uteroliths and ectopic ureters, as well. Just give the patient intravenous (IV) contrast medium, take some radiographs at five and 10 minutes, and you'll be able to see the ureters and whether they go into the urinary bladder or go out into the urethra if the ureters are ectopic, and then you'll have your diagnosis (see radiograph above).

Take note: It's easy to become distracted by the different contrast agent options-iohexol (Omnipaque-GE Healthcare), iothalamate meglumine (Conray-Liebel-Flarsheim), diatrizoate meglumine (Hypaque-Amarsham Health). But as long as the patient is normotensive and you don't have any hydration issues (or the patient is receiving IV fluids), any of these contrast agents should work well and safely.

While using contrast medium will provide some nice functional information, it's a bit all-or-nothing. It either pinpoints the problem, or it doesn't. For example, it can't help you figure out glomerular filtration rates, or things of that nature, but it can help you determine if a dog that's been hit by a car has a ruptured urinary bladder, ureter or urethra.


Anthony Pease, DVM, MS, DACVR, is an associate professor in the Department of Small Animal Clinical Sciences at Michigan State University's College of Veterinary Medicine.

Fun Fact: Pease plays ice hockey as a goalie and recently played in an exhibition game with the Carolina Hurricanes' 2006 Stanley Cup Champion team.