Intro to REI Ultrasound

Leslie King explains the basics of ultrasound in reproductive medicine, covering key techniques, anatomy, and abnormalities for new nurses and clinical staff.

Hi, I'm Leslie King, a nurse practitioner in reproductive medicine, and I'm here to talk to you about the basics of ultrasound in reproductive medicine. Ultrasound imaging and guidance is a vital aspect to our day-to-day operations. For nurses and clinical staff new to reproductive medicine, ultrasound is typically not a skill that they have much exposure to.

I feel particularly lucky that I started my career as a sonographer and then transitioned into being a nurse practitioner. But far too often, nurses and clinical staff who are new to the field have to learn on the fly and may be nervous to ask questions about the very basics. My hope is that this med talk will help those new to the field feel more comfortable with ultrasound.

In reproductive medicine, the vast majority of our exams are done with a transvaginal approach, while we still do use transabdominal for things like embryo transfers, post-op evaluation, things like that. As you can see here, this is the transvaginal approach showing a normal uterus. Over here we have the transabdominal approach.

You can see there are subtle differences like the width of the image and the clarity of the image. The first few images I want to show you pertain to the uterus. You'll notice lighter and darker shades of gray.

With ultrasound, the brighter or whiter an ultrasound image is, the more dense that tissue is. That helps us be able to differentiate between types of tissues. So here in the uterus, this very first picture shows a longitudinal or sagittal plane of the uterus.

The brighter area here in the middle is the endometrial cavity. Now over here in this image, this is a transverse view of the same uterus. You can see the brighter area going horizontal is that same endometrial canal.

A tricky thing with ultrasound, whenever we're looking in a transverse view, the imaging on the right side of the image is actually the patient's left side. So take into consideration those swaps whenever you're looking at ultrasound images. To dig a little bit deeper into the uterus, we want to evaluate the endometrium.

This can look different depending on where the patient is in their cycle. A lot of times we'll see this homogenous endometrium whenever they're at a baseline state. You can see the echogenicity is about the same brightness throughout the canal, where if you look here at this trilaminar endometrium, you can actually see the layers of the endometrium as they thicken more towards that mid-cycle.

Typically what we're looking for whenever we're evaluating the endometrium for an embryo transfer. Another very important area for us to evaluate with ultrasound are the ovaries. They can come in all shapes and sizes and they will look different throughout the menstrual cycle.

These images you can see here show a baseline state of the ovaries where the follicles are very small, but the follicles are those very small dark areas throughout the ovaries. Now to remind us what we learned earlier about densities, the very, very dark, dark colors on an ultrasound are going to be more fluid. So our follicles, which are fluid-filled cysts, are going to appear black on the ultrasound.

Those will start off small at the beginning of the cycle and will grow as we stimulate those ovaries to much larger follicles. Because the uterus is a potential space, that endometrial cavity tends to be collapsed down on itself during a typical ultrasound. So what we can do using a sonohistogram is to be able to add fluid into the cavity to open that space up to be able to evaluate for abnormalities.

You can see in this image a beautifully normal uterus as that fluid fills the cavity with no filling defect. You can see in this image we definitely have a defect in this uterus. Along the anterior wall, the upper part of the cavity, we can see an echogenic area where previously we had seen a nice open area.

That defect is an endometrial polyp. So far we've been focusing on normal anatomy, but we also have to see the abnormals as well. We can see endometrial polyps whenever we do a fluid ultrasound.

You can see the very echogenic area within the uterus. That would definitely interfere with an embryo transfer and needs to be addressed. Another abnormality that we see are uterine fibroids.

You can see a variety of uterine fibroids. They can be in different locations, not only interfering with the endometrial cavity, but the muscle wall layer, and they can even pedunculate off the side of the uterus. Ovarian cysts can wreak havoc in certain cycles, and that's why it's important for those to be evaluated as well.

You can see in this image the very dark circle is the ovarian cyst. Now, that looks very similar to a maturing follicle, and that's why it's so important for us to make sure that we are aware of where the patient is in their menstrual cycle. A cyst like this on cycle day two would certainly be an ovarian cyst, but if we saw this same size and look to a follicle on cycle day 12, now we're talking about a mature egg, and it's very important for us to be aware that stimulated ovaries look very different than typical ovaries.

The very dark areas are the fluid within those follicles. The brighter, more echogenic areas are actually the walls of those follicles, the areas that those physicians need to be able to penetrate through to retrieve those eggs. Speaking of egg retrievals, here's a beautiful image of an egg retrieval in process.

You can see the very bright linear area here at the top. That's the needle penetrating that follicle to be able to retrieve that egg. We also use ultrasound to guide those embryo transfers.

Here's a beautiful image of an embryo transfer where you can see the very echogenic linear structure. That's our embryo catheter. The teeny tiny echogenic area towards the top of the uterus are those air bubbles associated with that embryo transfer, and we certainly cannot forget about the reason why we are all here and do what we do, our OB ultrasounds.

Here's an image of an early OB ultrasound. You can see the small area. There's our baby.

Sonographers and providers will be taking measurements from the top of that head down to the rump to be able to accurately date that pregnancy. We can also use Doppler to listen to the heartbeat with our patients, a very exciting first step in their pregnancies. I hope this talk helped make you feel more comfortable with ultrasound.

It's just the tip of the iceberg, so stay tuned for more information.