What Type of Ultrasound is Right For Me?

Which ultrasound is right for me? Here at ReproScan, this is one of the most common questions we hear.

Well, the first questions I ask are: What are you doing? How often are you performing that exam? What other exams do you hope to perform?

We will work with you to choose the best probe type for what you are doing. There is not a one size fits all answer, which is why we love talking with you to help you choose the best ultrasound package for YOU. The right ultrasound probe depends on what you are wanting to ultrasound. Each probe can be used for different types of exams, so it greatly depends on what exams you will be performing and their regularity. Read on to learn a bit more of the basics of our most common probes.

While ultrasound probes may be designed for one specific thing, once you understand the parameters of your probe, you can use that probe for multiple exams (especially if you change some of the settings). For instance, the convex rectal probe was originally designed to make pregchecking cattle quicker and easier, but you can use that same probe for transabdominal exams on small ruminants, equine pregnancy and some companion animals exams. (Take a look at our “Understanding the Settings Series”)

It may be daunting to determine which probe type is best for your practice. Length, diameter, and feel are all important, but even more important are some of the settings parameters, such as frequency. The frequency range of a probe greatly affects the resulting image. So, let’s take a look into ReproScan’s five most common probe types.

Linear Rectal

o The linear rectal probe was historically the main probe for preg checking before the convex rectal probe was introduced. The frequency range is 4.5 to 7.5mHz. This means that you will get a clear image of an area about the size of a credit card. This is great for arm-in methods of pregchecking when one is performing short bred exams, ovarian exams, or equine repro exams.

o So, if you decide on a linear rectal probe you need to know that it will give you a nice image within the window of a credit card sized area. Exam examples: feline pregnancy, small dog abdominal obstructions, etc.

o This probe can be used with a ReproArm extension arm but can be a bit challenging to learn because of the smaller viewing area.

o The linear rectal probe is often the preferred type for practitioners wanting to offer extensive fetal sexing services as it offers a clear picture and is easy to manipulate arm in when searching for the bovine fetal GT (Genital Tubercle-see comments on fetal sexing article).

o This probe is also the most common probe used for ultrasounding for calf lungs.

o Physically it is designed to be streamlined with a slimmer probe cord design to be easier on your arm and wrist as well as compatible with the linear extension arm.

Convex Rectal

o The convex rectal probe offers a larger scanning area than the traditional linear rectal probe and therefore is often described as more versatile. Due to the larger size of your scanning area, you do give up a bit of resolution but gain about 7 times the scanning area. Envision a scanning area the size of a supersized pizza slice. This makes this probe ideal for those just learning to pregcheck, doing multiple stages of bovine pregnancy, limited equine, etc. The additional depth up to 22 cm, through the lower frequency typically in the 2-5mHz range allows the sound waves to penetrate deeper which gives you a larger image. This is particularity helpful with larger animals or smaller animals with excess adipose tissue.

o To understand the difference between a linear probe and a convex probe we use the analogy of searching in a dark room with a wide beam spotlight versus a laser light. The spotlight makes it quick to find the contents in the room, but the laser illuminates a single object very well.

o As far as the physical appearance and feel of the probe it is also designed to be streamlined for transrectal use as well as be compatible with the extension arm.

Micro Convex C20

o The micro convex C20 probe is designed for external ultrasound use. It offers a rainbow shaped ultrasound image which makes it a favorite for small animal ultrasound exams. With a frequency range of 5-9 MHz to and a depth range of 5-11cm it is a general-purpose ultrasound probe.

o Physically, the C20 probe is designed with a smaller footprint and a T shaped handle to make it easier to manipulate in small/tight spaces.

T Handle Convex C60

o This probe is also a good multipurpose probe similar to the micro convex. The main difference is that the C60 has a slightly larger arc and physical footprint than the C20. Envision a longer flatter rainbow whereas the micro convex is a tighter taller rainbow. The Frequency is range is 2-5MHz allowing for a depth range of 6-20cm. As with the convex rectal probe, the lower frequency allows for better penetration of adipose tissue and a larger window for deeper exams such as larger dog pregnancy, transabdominal equine, small ruminant transabdominal exams etc.

o This probe is very similar to the convex rectal probe except for it is oriented into a t handle configuration for easier external manipulation and it is not fully submersible.

T handle Linear L40

o This probe offers a higher resolution, shallower exam. With a range of depth of 3-9cm and a higher frequency (6.5-9.5MHz) this is a favorite for tendon ultrasound, smaller small animal (particularly feline) use and surface level ultrasound exams.

o This probe is also a T handle probe making it a bit easier to manipulate than the rectal probes.

o A standoff can be purchased for the L40 ultrasound probe which can be quite helpful when doing tendons (see Dr. Hutchinson’s post about tendons where he talks about standoff vs not).

This is a lot of information, please know that we are here to help and support you. Whether you are looking for new ultrasound or want to utilize the one you currently have a bit more, give us a call.


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