Those of you who’ve trained with the Animal Ultrasound Association will already be familiar with how different probe types can affect image quality. But seeing it in action—like in the scan video below—brings that learning to life.
In this late-stage pregnancy scan of a Cocker Spaniel, captured on a Vinno D10, we compare two probes: a microconvexand a linear transducer. The first half shows excellent images achieved with the microconvex, while the second half demonstrates what’s possible when a high-frequency linear probe is applied:
Did You Know…
Foetal intestinal activity in dogs begins approximately 13 to 9 days before whelping. In humans, similar movement appears between 22 and 20 weeks before birth. This motion can actually be seen on ultrasound, especially when using a linear probe, which offers the clarity needed to visualise even subtle physiological activity.
Take another look at the scan video—watch closely around the pup’s abdomen. You’ll see the early definition of the intestines, and it’s not hard to imagine being able to observe peristalsis as gestation progresses. This kind of detail can serve as a useful marker when estimating a whelping window—a valuable insight for those of you scanning professionally.
Microconvex: Your Everyday Workhorse
Microconvex probes remain the recommended all-rounder for small animal pregnancy scanning. They provide excellent depth, a broad field of view, and good access in curved areas of the abdomen. You’ll see the foetal heartbeat clearly, and overall structural definition is more than adequate for routine scanning.
That’s why the AUA consistently suggests a high-quality microconvex as the primary probe for paraprofessionals and vet techs. It balances cost, performance, and practical handling extremely well.
Linear: For When Detail Counts
Switching to a linear probe instantly sharpens resolution—particularly in the near field. You’ll notice clearer tissue boundaries and more refined anatomical detail. This is due to its higher frequency, which produces shorter wavelengthsand sharper definition in superficial areas.
With breeds like the Cocker Spaniel, the foetuses tend to sit quite close to the abdominal wall. This allows the linear probe’s strengths to come into their own, as deep penetration isn’t required.
When Should You Use a Linear Probe?
While the microconvex will serve you well in 95% of pregnancy scans, understanding when and why to switch to a linear is an excellent skill to develop. If you’re working in a clinical setting or have access to a higher-end machine like the Vinno D10, adding a linear probe to your scanning setup can provide exceptional value in specific cases.
In summary:
Linear probes offer markedly better near-field imaging—and when detail is critical, such as observing intestinal activity or assessing placental edges, they’re a powerful tool to have in your kit.