Ten Basic General Practice Ultrasound Tips and Tricks
PRACTICE! PRACTICE! PRACTICE!
That is the key to perfecting your ultrasound skills, but you may be wondering how you even get to that point. Many of us didn’t get much ultrasound experience in veterinary school, so it can be challenging to get used to it. I, like many of you, didn’t either, but I didn’t realize how helpful it can be until I actually got into private practice, helping with anything from getting a sterile urine sample to checking for free fluid in the chest or abdomen. Now that I don’t have regular access to an ultrasound, I miss it a lot, taking it for granted when I had it. Getting acquainted with it to get more comfortable using it slowly is the first step, so here are ten useful tips & tricks to help:
(1) Every ultrasound machine is different, so get used to yours before trying to use it on a patient. I know there are many different buttons and knobs! Before using it on a potentially aggressive patient or very wiggly puppy, take your time to get used to what they are and how they may help you in different scenarios. You will thank me later.
(2) Don’t be afraid to reach out to your ultrasound rep! They are there for you. They are more than happy to help you get familiar with the machine, walking you through all the different settings. They can even help you if you are having particular issues.
(3) Get used to your different probe options (if you have a choice). Higher frequency probes have decreased tissue penetration, so they are better for more superficial structures, providing better resolution. On the other hand, lower-frequency probes can penetrate more tissues, so they are better for deeper structures. Linear probes are especially lovely for cats (unless they are obese) since they are better for more superficial structures, giving you better detail. Once you have decided which probe you would like to use, determine which side of the probe corresponds to the image on the screen. This is especially important for orientating yourself. I usually place my finger on one end to verify because sometimes it is difficult to be sure just based on the markings on the probe, and I’ve been fooled on some machines. One side of the probe has unique markings. This side of the probe should always be pointing in the cranial direction when scanning sagittally, to the patient’s right when scanning transversally, and toward the dorsal direction when scanning on the lateral body when the patient is in dorsal recumbency (the traditional position). The image can be flipped on the screen itself, so you would have to look for the marker on the screen that matches the notch on the probe; it may not always be left (though that is the default) if someone has flipped the image on the screen on its last use.
(4) For the most part, you don’t need a lot of pressure. You only need light contact with the skin to get a good image. However, sometimes you need a little extra pressure to move gas away, like in the colon, to get good visualization. Other times extra pressure helps bring structures closer to your probe to get a sample, like getting urine in a fat cat.
(5) Lube is your friend. That is safe to assume in most situations, but, in the case of ultrasound, it provides better contact so you can get clearer images. So, if you can’t see something well, try applying more ultrasound gel.
(6) Try a different angle if you still can’t see something well. In fact, multiple angles are a good thing regardless to get a complete picture. Not only should you scan something both sagittally and transversally, but you should also slowly rotate the probe in a clockwise or counterclockwise fashion to ensure you are visualizing the entirety of an organ, especially important with the spleen since splenic tumors most often like to hide on the head of the spleen.
(7) Changing the position of the patient sometimes helps. Have them stand if you are checking fluid. Then the fluid will be closer to your probe, working with gravity. Sometimes it is easier to visualize certain structures when they are in lateral recumbency, like the liver in deep-chested dogs.
(8) Ensure you are at an appropriate depth for the structure you want to visualize. It is amazing how much changing the depth will affect your image, especially if it is a superficial structure and you don’t need to visualize everything below it. Remember to change your focal zone, too, because that area will have the highest resolution. It should be set at or just below the area of interest.
(9) Doppler/color flow can help determine if or how well something is vascularized, which can often help determine what something is. For example, if you notice a mass, sometimes Doppler may help determine if it appears more cancerous or just an abscess based on the amount of blood flow. Or it may help determine prognosis, like assessing the blood flow in a spleen if you are concerned about splenic torsion.
(10) Practice on patients that you are anesthetizing for other procedures. It is much easier to practice on relaxed abdomens, especially if you are trying to find those elusive adrenal glands. It also helps to get acquainted with variations of normal, so you will feel more comfortable determining something abnormal when you see it.
I know I already said it, but I’ll say it again: PRACTICE! PRACTICE! PRACTICE! Even if you use it to check for bladder stones on a cat with hematuria or for pericardial effusion on a dog with muffled heart sounds because it is quicker than radiographs (and saves your staff x-ray exposure!). Before you know it, you’ll start to be braver, checking for a gall bladder mucocele when you notice significantly elevated liver values on bloodwork in a sick dog. Trust me when I say that your ultrasound machine will soon become indispensable, and you’ll be glad you have it (and perhaps miss it when you don’t).