Introduction to Breast Ultrasound - SD

Introduction to Breast Sonography

Hi, this is Cindy Rapp and we're just gonna give a brief introduction to breast sonography.

Patient Positioning

What we're gonna talk about, first of all, is patient positioning and annotation.

Now if we're scanning a lesion in the upper outer quadrant of the right breast, a lot of times what we're gonna do is roll the patient in an opposite posteriorly.

So if I'm scanning the right breast, I'll roll them in the left posteriorly from medial lesions in the breast.

What we wanna try and do is thin the tissue planes out as much as possible.

We'll go ahead and roll the patient's supine and thin the tissue out that way for fairly large breasted patients and lesions in the lateral aspect of the breast of a lot of times what we'll do is roll the patient into a left lateral decubitus.

Once again, we're trying to thin that tissue plane out as far as possible after we've rolled the patient and sort of got the breast thin that way.

Then the next thing I'll do is have the patient bring their hand up and over their head.

This helps pull the tissue planes much tighter and a lot of times it will thin the breast tissue planes out even more.

That rarely do we have to scan beyond about three centimeters in depth when we use our high frequency linear array transducers.

Annotation

Next thing I wanna talk about is annotation.

Now pretty much all lesions in the breast, we use the clock face for documenting where we're scanning lesions.

If we are sending a lesion for biopsy, we will measure centimeters from the nipple out.

And one thing that you can do in measuring centimeters from the nipple out is use a ruler to measure exactly how far it is.

And some people I've seen take a marker and actually mark centimeter markers on their transducer face so that they can use that as a ruler.

Another method of we use for annotation is using what's called the A BC 1 23 method.

We will still use this method if we're just scanning cyst or normal type tissue, but once again, anything going for biopsy, we will use exact centimeters from the nipple out.

The way that the ABC 1 23 method works is if a lesion is close to the nipple, we consider that region one lesions that are midway out in the breast are area two, and if a lesion is in the periphery of the breast, we will label that region three.

So now in annotating my films also, if I'm scanning behind the nipple, I will label SA for subular and ax for axilla.

You can see here that now scanning the right breast at 12 o'clock, I know that the lesion is in position two, which tells me it's midway out in the breast at the 12 o'clock position.

The next thing we'll do is look at the depth of the lesion.

If a lesion is very superficial, we label that A.

For lesions that are midway down in the breast, we will call that region B.

And A lesion is deep in the breast and up against the chest wall we will label that C.

So now in annotating my films, I would type in right breast 12 o'clock to C.

It tells me it's at the 12 o'clock position halfway out and up against the chest wall.

When I first started using this method, I had a hard time remembering which was A, B, C, and 1, 2, 3.

What I remember is A is anterior, C is chest.

So it's much easier to use those methods Now just showing you example of a lesion in the left breast 1 33 B and also 12 o'clock two C, and how quick and easy it is to use these annotation methods.

But once again, if a lesion is going for biopsy, we will measure actual centimeters from the nipple out and document it that way.

Scan Planes

Now looking at scan planes, the number one cancer that we see with ultrasound is ductal carcinoma.

Cancer likes to take the path of least resistance.

So as it starts to grow, a lot of times before it becomes invasive and breaks through the ducts, it will grow back towards the nipple or may branch out away.

If we scan in our standard longitudinal and transverse planes, you can see how we make this lesion look like it's fairly well circumscribed.

For breast sonography, what we'd rather do is scan in more of a radial plane, which is running the same way that the ductal system does.

And then our anti radial view is just rotating the transducer 90 degrees to wherever our radial scan was.

So you could see that if you were scanning at 12 o'clock radial, that is the same projection as a longitudinal view.

Rotating the transducer 90 degrees would be an anti radial view.

And here, just showing you an example, scanning the right breast at 10 33 B radial and the image to the right is showing an anti radial scan rotating that transducer orthogonal to wherever your radial plane is.

Normal Anatomy

Next we'll talk about the normal anatomy.

The first structure that we're going to see when scanning is the skin, it should be echogenic and about two to three millimeters in thickness.

Then there's going to be a layer of subcutaneous fat that should be at medium gray.

We then have a pre mammary fascial layer.

This is what separates the mammary zone from the subcutaneous fat within the subcutaneous fat.

Many times we can see Cooper's ligaments.

These are the suspensory ligaments of the breast and they actually attach deep against the pectoralis muscle and travel all the way through the breast and attach at the skin.

We then have the mammary zone.

This is where the majority of breast cancer is going to arise, is within the mammary zone.

There is a retro mammary fascial plane that we rarely see sonographic, a retro mammary zone of fat.

And one thing you wanna make sure is that you can see all the way to the pectoralis muscle when you first start imaging.

So you don't cut a lesion off if it's deep against the chest wall.

So here's just showing you an example of an ultrasound image.

You can see the skin correlating nicely to the echogenic, that we're seeing compared to the diagram.

Here is that area of pre mammary fat.

This is a Cooper's ligament extending up.

This is looking at the fibro glandular tissue pattern.

We can see pectoralis muscle running through here clear down to the lung field.

Now looking at this type of pattern where we see these holes coming through here, kind of looking like a Swiss cheese pattern, I've heard some people refer to that as ductal ectasia.

This actually is not ductal ectasia.

We can see a normal duct that's collapsed right here.

This gray tissue surrounding the duct that we're seeing is actually just loose stromal tissue that we see surrounding the ducks.

Looking at the right hand image, you can see the pathology specimen of this.

You can see the normal collapsed duck centrally and the white arrows are pointing to that loose stromal tissue.

The fibroelastic tissue and this is what as I mentioned, allows ducks to expand and contract during lactation.

If we look at the ultrasound image, the left hand side, this is the normal duck elongated.

Here you can see the walls are tightly opposed.

This is a short axis view of it and that gray that we see is just the loose stromal tissue surrounding that.

A lot of times we see this type of pattern in women, I'd say in their late thirties, early forties.

The older we get, you get more fibrosis of that loose stromal tissue and it tends to start to blend in with the surrounding tissues as we get a little bit older.

This just showing you variation of normal of some mild ductal ectasia.

The image on the left is a normal collapsed duct.

The image in the center, you can see that there's just a little bit of ductal ectasia separating the two walls of that lumen of the duct.

And then the image of the right we see just a little bit more ductal ectasia.

If these patients are asymptomatic, we do not get concerned about seeing this amount of fluid in the duct.

Basically it's a normal variation.

50% of the women over age 50 will have some ductal ectasia.

So normal variations of the breasts that we can see with age changes.

This is looking at pretty much a fairly young patient where we have a lot of that fibro glandular type pattern.

As we get older, what you're going to see is more fat starting to come in into this pre mammary fascial area or fatty area.

The mammary zone itself starts to think you or shrink somewhat.

You can see the Cooper's ligaments extending up As we get older, we get more fatty replacement into this anterior portion.

We're starting to see more fat coming in on the posterior area and less of the actual fibro glandular pattern.

Here you can see even more fatty evolution of the breast.

These are Cooper's ligaments extending all the way up.

Very little bit of the fibro glandular tissue is left down to the pectoralis muscle until we have a completely fatty involuted breast.

And here's just a diagram showing you actually the images.

Here's your normal all the way getting into a fatty involuted breast.

So these are just some normal variations that we will see as we tend to get older with breast ultrasound.

Mammographic Sonographic Correlation

Next we're gonna talk about mammographic sonographic correlation.

Very important if the patient has had a mammogram to correlate the images with what we're seeing on ultrasound.

Now there is one difference between breast sonography and the mammographic algorithms and that's looking at operator dependence.

There are a lot of excellent mammography technologists out there who are very good at taking images.

But what's very difficult is for the radiologist to look at those images and determine exactly what's going on with these microcalcifications or this area of architectural distortion or whatever's going on.

With sonography, it's pretty much the opposite.

Getting the good images is what is difficult.

Once you have a good image, the interpretation is fairly easy of that, but once again, there's things like moving your focal zones, using the right amount of pressure and all these types of things.

It's very important to make sure you're doing in using sonography.

Scan Planes in Correlation

Now looking at mammographic sonographic correlation, looking at your scan planes, a transverse plane during ultrasound is pretty much the same as looking at your CC projection of the mammogram.

So if you're looking at the CC projection, if you have a lesion on the medial aspect, that's where it's going to be located on ultrasound is gonna be the medial aspect of the breast.

What gets more difficult is to look at the degree of obliquity on the MLO view and try and determine, we don't know with ultrasound at what degree of obliquity the mammogram was taken.

So this is sometimes where images that are actually more superficial, than they really are will actually appear to be higher in the breast when they really are lower.

So it gets more difficult for us to evaluate these sonographic.

So looking at the correlation and looking at location, one thing important to realize is that if you have a lesion that is lateral appearing located more superiorly than they really are on the MLO mammogram, the more peripheral that these lesions lie, the higher that they will project on the MLO view.

Just the opposite is with the medial lesions, they appear to be located more inferiorly than they really are on the MLO views.

And the more peripherally they lie, the lower they project.

On the MLOI always have problems remembering which way to look.

So one thing that I remember is, remember M if you're dealing with a medial lesion, you need to look up.

So a lot of times if you have a medial lesion on the mammogram, it may appear to look like it's at the four o'clock position in the right breast and actually it's lying clear up at the two o'clock.

So just remember mup medial lesions look up higher.

Mammographic Densities

Next we're gonna talk about mammographic sonographic correlation.

In dealing with mammograms, there's basically three densities that we deal with.

Fat density, which is anything gray on the mammogram.

Calcium is just a benign calcification that we can see here.

And the third mammographic density is a water density.

A water density is anything that is white mammographically.

So here we can see there's a mammographic lesion.

It's a water density.

This is where ultrasound is very helpful in looking at this water density and determining what we are dealing with.

So whether all the different things that can make up a water density mammographically, the most obvious would be a cyst.

A cyst is a water density on the mammogram and so is normal fibrous and normal glandular tissue.

And you can see the fibro glandular tissue throughout the mammogram that we can see on the left.

Also, any solid nodule does not matter if it is benign or malignant will appear as a water density mammographically and also muscle and skin will show up as water densities mammographically.

So once again, this is where ultrasound is most helpful in looking at these lesions in determining exactly what we're dealing with.

Examples of Correlation

Now this patient presented with a palpable lump.

On the left hand side you can see the bb.

This is pretty much a fatty involuted breast will ultrasound added a lot of information, not really.

If you do an ultrasound, expect to see something that looks like this.

We have the skin that is here.

Here's that pre mammary fascial layer traveling along a cooper's ligament coming up.

The entire mammary zone is replaced with fat all the way down to the pectoralis muscle on fatty involuted breasts.

This is where mammography is much more sensitive than sonography and things really won't be missed on a mammogram.

Here we have another patient's mammogram.

You can see another BB on the left side of the breast, a very dense mammogram doing a correlation with ultrasound.

You can see that we have the skin here.

You really can't make out the pre mammary fat versus the mammary zone.

It just sort of all blends in down to pectoralis muscle.

This is glandular tissue.

This is typically what a very young patient, so we're talking about a young girl in her early teens.

The breast pattern appears very glandular like this and typically they would never have a mammogram or anybody who is lactating or maybe pregnant, you can see that they will have very dense mammograms.

And also with ultrasound, we've got a very gray background that it might be easy for us to miss a lesion that is iso co to the surrounding tissue.

Another mammogram that's very dense, the BB marking on the right hand side.

You can see now with ultrasound we have more of the fibro glandular type pattern.

This is what ultrasound loves is when we've got that white background, lesions are gonna jump right out at us.

It makes it much easier for us to see when we've got more of that fibro glandular background.

Now if the patient has had a mammogram, before you do the ultrasound, one thing I like to do is actually take the films into the room with me and hang them up on a view box.

They're kind of my roadmap to look and see where lesions are located.

Four things that we wanna compare.

We wanna look at the size of the lesion, we wanna look at the shape of it, figure out where it's located, and then also look at the surrounding tissue density.

So the first thing in looking at size, take into account everything that is a water density.

If we know that we're looking for a two centimeter mammographic lesion, we go into skin and all we can find is a one centimeter cyst.

If that one centimeter cyst is surrounded by fibro glandular tissue, that may be why your S size does not match up.

So typically what I would do would be measure the cyst and then take one caliper and measure across including the fibro glandular area.

But remember, everything that can make up a water density may be why your sized does not match up if you're doing your correlation.

The other thing is how do we measure lesions in the breast?

We all know that if we're measuring A BPD, we measure leading edge to leading edge.

If you're measuring an aorta, you measure outside to outside common bile duct inside to inside.

But nobody's really established how to measure lesions in the breast.

Some people may just measure the fluid on a cyst.

Some people may include the pseudo capsule.

One thing we do is include the capsule on all of our measurements.

You just wanna make sure that everybody in your department is measuring the same, that if the first person measures inside the inside, your patient comes back for a six month follow-up and the next person measures outside the outside, that may be why your size is not matching up.

So we do include the capsule on all of our measurements.

Looking at mammographic sonographic correlation, you can see the green arrow is pointing to a mammographic density in the lower aspect of this left breast.

On ultrasound, we can see that there is this area of fibro glandular tissue corresponding to what we're seeing here on the mammogram.

Now this is probably one of the most common questions I get asked is we can see a lesion on the mammogram.

I go in and scan and I scan around forever and cannot find anything.

Why is that? A lot of people don't realize that normal breast tissue can create a mammographic pseudo mass.

So typically what we would do in this case is have the patient go back and get a spot compression view and that tissue should compress out.

But you can always be sure that if you have a water density area of fibrous tissue that can cause one of these mammographic pseudo nodules.

Also looking at mammographic sonographic correlation, you will see a 90 degree rotational difference when you compare the mammograms to the ultrasound.

With mammography, the tissue planes are being pulled away from the chest wall and compressed down.

And with ultrasound, we're having the patient lie flat on their back and so the breast is being compressed against the pectoralis muscle.

So here we can see this lesion on the CC projection of the mammogram.

It is perpendicular to the chest wall.

Once we have the patient go in and lie down on their back on ultrasound, it's rotated 90 degrees and is now parallel.

So expect to see that normal 90 degree rotational difference comparing mammography to sonography.

The other thing is lesions will always be closer to the chest wall on ultrasound when compared to the mammogram.

Remember once again, the mammogram is pulling the tissue planes away from the muscle.

With ultrasound, we're having the patient lie flat on their back and they're being compressed down.

Here's a nice example.

You can see the green arrow pointing to this mammographic lesion.

It looks like it's a few centimeters away from the pectoralis muscle.

On ultrasound. We can see that it's actually indenting into the pectoralis.

So lesions will always appear closer to the chest wall on ultrasound looking this mammographic lesion at the shape and surrounding tissue density.

You can see right through here, there is an area of architectural distortion.

You don't want anything pointing up into that area of fat.

So we went ahead and scanned this patient mammographically.

This would be given a Birads four classification, an ultrasound going in and taking a look.

We have an area of ductal ectasia that extends up into the fatty tissue.

You can see that we have fat anterior to it that corresponds nicely to the fat that we're seeing here.

There is a ridge of fibro glandular tissue that corresponds to what we're seeing here.

And this is just some ductal ectasia extending up and you say, well Cindy, how come I don't see the whole duct?

But remember, it's hard to take one sweep that shows what you can see.

If you could angle the transducer over to the side, you'd be able to see the rest of the duct extending up into this area.

So now with ultrasound, we've been able to take what was given a birads floor classification, which would be recommended for biopsy, and now turn this into a birads two, which means this patient does not need any further follow up.

And this is the one I think we all hate.

You get a patient that has one mammographic that still do, it's in the upper outer quadrant of the right breast.

You can see it in both views.

And this happens to be the patient who has her mammograms on the 14 by 17 films and you get the short straw.

So you go in and start scanning.

You're in the room what seems like for an hour and you can't find anything.

Well, if you can't find anything, one thing you know it's going to be solid.

A lot of times these lesions are iso coic looking for the echogenic pseudo capsule that surrounds.

It may be very helpful in finding these.

But another thing, notice here that there's a blood vessel running adjacent to this.

Now we remember our anatomy.

We've got our lymphatics that run right next to the blood vessel.

So one thing that I'll do is turn color doppler on, start up near the axillary segment of the breast with color doppler on in a transverse plane.

Just slide, find a vessel and come down into the breast.

And a lot of times you will see these small intary lymph nodes adjacent to blood vessels and it makes it a lot easier to find these sono graphically.

Well, hopefully this has been helpful.

Once you all understand breast sonography, you'll love it.