Contrast Enhanced Ultrasound: How to Get a Program Started - HD

Introduction

Great, thank you.

This is quite an honor
and I really appreciate having been asked to do this.

Contrast ultrasound is something
that a lot of people are just getting started doing
and I was asked today to just give an overview of
as it says, how to get started.

I'm not gonna be showing great clinical cases,
just letting people know some of the issues
that we may face in our hospital, in our practices
as we start to do this.

I have one grant disclosure, which is shown here.

Understanding Contrast Agents

I think as all of us know as radiologists,
contrast agents basically are injected
or used to change the property of a structure.

With regard to the surrounding organs,
you're basically changing the signal to noise ratio
for x-ray and CT. For many years we've increased density
of certain areas by injecting iodine compounds. In MR
we tend to change the magnetic signal by using gadolinium
and with ultrasound.

The area or the stuff that's been used the most
of course reflects, it increases reflection
by the injection of bubbles
and bubbles come in different varieties
and we'll talk a little bit about that as we go on.

Most of this that we use now are not air bubbles,
but they are specialized compounds that will allow them
to pass through the barrier of the heart and the lungs.

Whenever we inject a contrast agent,
and Harriet's already touched on this, we want
to think in terms of toxicity versus benefit.

And it's very obvious to most of us at this point
that these bubble compounds
that we're injecting are extremely safe.

When you use a contrast agent, one
of the things you need to do is have an easy access site
and in bubbles when using bubbles,
the bubbles have to go from the pulmonary
through the pulmonary vasculature
and out into the systemic circulation.

If we're able to achieve any kind
of really largely useful use of these agents
to get arterial
or parenchymal imaging, most of the agents that we deal
with at this point have consistent particle size.

Most of the bubbles are about the size
of a red blood cell or smaller.

When it comes to ultrasound,
the agents must remain intact for a sufficient amount
of time for us to actually be able to perform a scan.

Most of the agents at this point have a lipid
or some form of surfactant shell, which keeps them intact.

Most of them also consist of some form of fluorocarbon gas,
which is not soluble in blood.

This is one of the problems
with injecting just bubbles.

Air bubbles in general, they do not pass
through the pulmonary vasculature and the heart.

Again, we need a realistic amount of time of enhancement
to allow us to scan.

And if you have too much,
that can become inconvenient if you want to do
multiple injections. One of the major advantages
of the ultrasound contrast agents,
and we emphasize this both to our patients
and to the clinicians, that these are not nephrotoxic.

Many patients will come in.
In fact, some labs will say,
we don't call it contrast at all.
We call it a bubble study because many patients will walk in
and say, oh my God, I had a contrast study,
you're not doing another one of those on me.

These things are definitely not gonna cause the same
problems that many people have experienced
with iodinated compounds.

These things have a really excellent safety profile.

Practical Implementation: Formulary Approval

There are some basic things which shall we say.
I've been doing radiology for a while
and I really didn't expect to experience.

One of the first things was that I had to go
before the formulary committee
and get approval to actually use these agents.

Now at my county hospital,
I told them I could eliminate MR scans
and within two days I had approval.

It's a county hospital, we don't get paid for those.
MRs. Most of us will have to go then
and present something before the formulary committee.

For many years we basically scrounged the
stuff from cardiology.
We would just go over, knock on the door
and get a bottle of Definity and use it.

Now that Lumason has actually been approved as of last April
for use outside of the heart.

This was one of the things that made it easy to get
through the formulary committee
and that was basically, wait, you're not going
to force me to use something off-label when there is
something that is now available and approved by the FDA.

Again, most of us
who practice in a hospital setting will have to deal
with the formulary committee, the P and T committee.

Those are a couple of things that can help us get through that basically that, look,
you would probably prefer that I'm using a labeled,
approved agent rather than one that's not approved.

IT and Administrative Issues

One of the other things, there are several IT issues
that most of us deal with when it comes to contrast agents.

The major surprise for me was when the clinician said,
oh, I can't order it.
There's no orderable in the EMR.

One of the things you need to do is
to make sure you discuss with your IT group
that there is some way
that the clinician can actually order a contrast scan.

Usually we have an ultrasound
of the abdomen with contrast.

We also have one ultrasound of the kidneys
or retroperitoneal limited with contrast.

Do be sure that you talk to the IT folks so
that your clinicians actually can order these things.

Billing

Billing of course has been a major issue.

At this point there is a hospital code so
that the hospital or you can get paid
for the technical component of the examination.

There is the number there.

It is ultrasound abdominal with contrast.

At this point I am very happy to say,
and Harriet mentioned this a moment ago,
that the ACR has been incredibly,
incredibly hardworking on getting a CPT code approved
for this so that we as clinicians can actually get paid.

And just as of a couple weeks ago, the
CPT code for ultrasound
with contrast was actually approved as a category one code.

Now of course, the problem with that is
that doesn't kick in tomorrow, so
that will probably be available as of January, 2019.

But that was a big hurdle.

We were very worried that it was not going to be approved
as a category one,
but actually again,
the ACR folks just did an amazing, amazing job.

A lot of really hard work to get that thing through.

There is an RSNA meeting which will happen in January,
at which point we'll have more information about the actual
amount of reimbursement that we're talking about.

And just practically speaking, in the abdomen,
basically we get paid for an abdomen limited.

Probably shouldn't go out to the FDA that we do this,
but basically we actually bill for an abdomen complete,
abdomen limited with Doppler limited.

If we do a liver, if we're looking for a mass
and we've actually had no pushback on that,
basically if I'm looking for a liver mass,
I feel justified in examining the hepatic veins
and the portal vein.

And with that you can then actually bill
for a Doppler limited.

Image Transfer

One of the other IT issues that we face is image transfer.

Remember that most of what we do are large clips.

And again, one of the things from the consensus conference
that will probably be published is a little bit more
information on how to record
and what to record and when to record.

But these clips can be very large
and it's really a good idea
to get your IT people on board right away so
that they start looking at your machine
and how to get those images transferred into the PACS.

For the most part, I really do prefer to see the clips.

We also take static images throughout the examination
because they're easier to show
to the clinicians for example.

But this is really the problem
because these clips can be extremely large.

There are several ways around this.

Some of the scans we've actually broken up,
so we'll scan say for 30 to 60 seconds
and then stop scanning, start another clip.

That makes it a lot easier to do the transfers.

One of the problems we recently ran into,
however, is if you're trying
to do a TIC curve quantification curves,
you need the entire sequence.

And so that may be quite challenging.

I don't have an answer for that.

Each of you may have to actually talk
to your IT people without dealing with the clips.

If you break them into smaller pieces,
it's probably a lot easier to do the transfer
and you'll run into less problems.

Scanning Logistics

One of the other unique issues that we deal
with when it comes to contrast ultrasound is
who does the scanning?
Who does the injection?

Typically we have a doc tech combo where one
of the physicians will actually go with the tech.

I think it's very advantageous for the radiologist
to review any previous
or outside studies so we know exactly
what we're focusing on.

Generally the physician will do the injection
and the tech will scan,
and it's really something,
I don't think you can actually expect one person
to do the whole thing themselves
because you can't concentrate on the lesion
and squirt the contrast injection and do all these things.

I think having two people
on the scan at the same time is probably the best.

Typically we and
or our technologist will take selected static images.

Again, they're real nice to be able to see,
say a representative example of the arterial enhancement,
a representative image
of the washout rather than having
to show the clinicians the entire clip.

As I said, one of the things that will come out
of the consensus conference
that we don't have here in the United States are
well-established scan protocols,
and that's something
that will probably be published when this paper comes out
from the consensus conference, exactly how that's done
for each of the various organs.

Image Display and Scan Tips

One of the other unique things about contrast ultrasound
is the image display.

If you look at the image that you see here,
this is a real time clip on the left,
the gray scale image, whichever that direction that is,
but on the left you can actually see the gray scale image.

Remember when you begin, there is basically a blank screen
where the contrast will be visualized and it's
because it's almost a subtraction technique.

You can see there that there is nothing present.

Once the scanning actually begins, the
material comes into this, in this case the kidney,
and is visible.

That screen where the contrast is actually shown is a
pure image of the harmonics coming off of the bubbles.

And for that reason, you need that dual image so
that you actually have a reference point when you start
and then gradually the contrast image will show
up on the other one.

One of the things that is a bit frustrating
and it varies with the vendor is when you go into contrast
mode, the gray scale image may degrade somewhat,
and again, look at that and check that with your vendor
because it is sort of specific to some vendors
and more severe in some units.

Just a couple of quick scan tips.

Remember that you can't scan at 20 centimeters
of depth with contrast.

Many times you're going to have to try to get that lesion
that you're looking at as close to the transducer
as possible, usually less than 10 centimeters,
so you may need to scan from various windows
until you can get that into a more optimized position.

Also, if you're scanning the kidney, it's a good idea
to not use the liver as we normally do, as a window
to visualize the right kidney.

One of the other things just practically speaking is
practice breath holds with the patients.

You don't want the patient at the last minute
after you've injected fighting with them just,
oh, now hold your breath.

It would be best
to actually practice a few breath holds
with the patient beforehand.

And in Los Angeles, a lot
of our patients don't speak English,
so we even have language issues that we have to deal with.

A good idea to do a little practice breath hold
before the actual injection.

One of the other unique things that is good
to keep in mind, many things will happen within seconds
that you just normally don't even see when you're looking at
the live images.

And afterwards when we do, for example,
the first injection, it's not unusual for me to go back
and ask the tech to actually, let's play
that clip from the beginning and look at those two
or three seconds where I can see that hemangioma filling in
or where I can see that starburst pattern with an FNH.

A lot of times going back and doing a frame review, even
after the fact on your PACS machine
or on the ultrasound machine itself may actually give you
information that
otherwise just goes by so quickly you can't even see it.

One of the other things, just practically speaking,
lengthwise imaging, if you're imaging in a transverse plane,
the lesion will often go in and out.

If you image longitudinally,
that may actually provide some information that you would
otherwise lose as the patient breathes.

That way it keeps it in the plane
and you may have a better advantage than you would if you
were actually scanning in the transverse plane.

Quantitative Imaging

I don't have the time to go into this,
but basically, most machines
or almost all machines actually do provide the ability
to do quantitative imaging.

Most of the time when I look at a lesion,
I know what's going on by the time we leave.

This is just a very nice graphic example
of a hepatocellular carcinoma.

You can see here the blue represents the ROI
from the lesion itself.

The red represents the surrounding liver.

You can see the classic picture
of a hepatocellular carcinoma where you have increased
opacification early on,
and then you can see the two curves actually cross
as you go into washout.

As I said, we don't do that with every patient,
but it is something, it's a nice feature
of contrast ultrasound that it can give you graphic
representations.

Patient Safety and Informed Consent

From the standpoint of safety.

We treat informed consent the same way as we do CT
and MR in our institution.

We do not get written informed consent for CT or MR and
therefore we don't do that.

For contrast ultrasound,
we do give the patient a simple information sheet
and we do talk about the fact
that there may be anaphylactic reactions,
which are very rare, as was mentioned by Harriet.

You can have headache a little bit of sensation of warmth.

Probably the most common thing we get is the patient
complaining about pain near the IV, which we usually say,
sorry, but that's actually the saline
because really I'm only injecting a couple
of drops of contrast.

It is recommended that patients are monitored.
By the time the patients get up off the table,
we've cleaned everything up,
the patient's gotten dressed most
of the time they're ready to go.

On the other hand, do remember particularly in the
outpatient setting, it is just like any other contrast
enhanced examination important
that there is an available crash cart
and that there is an empty bed available
for any complications that may occur.

One of the other things that was also mentioned is
that there was a shunt contraindication,
which has now been removed by the FDA.

Preparing the Contrast Agent

Depending upon the type of contrast that you use,
the activation may be somewhat different.

This is a picture of Lumason
and the way it comes in a little plastic container.

There's a bottle here which has the material within it.

There's a little injector thing,
and then there is a saline filled syringe.

Basically, you put all that together,
you inject the material into the bottle
and you hand shake it.

This is Definity, which is one of the other major
entities that is used.

This basically is similar.

You inject the saline into the bottle, then you withdraw it.

The difference with Definity is it actually needs,
the vial needs to be placed into one
of these vial mix things and you hit it
and it shakes it violently for about 45 seconds.

A different way of
activating the materials depending upon
the brand that you're using.

Always I tell the residents
as they're standing there shaking away, look at the bottom
of the vial.

If you see that there's still white gunk in the bottom
of the vial, you've probably not shaken it enough.

That ought to be clean and completely in suspension
because remember, you need to have as much of
that material within suspension as you can get.

IV Access and Injection Techniques

One of the last problems that I'm going to talk about is
that of an IV.

Remember, most ultrasound techs do not start IVs,
so this is a whole potential for new learning.

On the other hand, at least in my institution,
most of the patients will come in for their CT MR
and now ultrasounds go immediately to the nurse.

The nurse puts the IV in and then sends them to us.

And that is probably more
practical at some point.

However, it will probably be necessary
for ultrasound technologists
and also depending on your practice
and what you have available to actually be starting
the IVs. Most people would say you need at least a 20
gauge needle or
larger, so that the bubbles are not broken.

We use a three-way stopcock.

Basically we attach the saline flush in one direction
and then in the straight direction we attach the contrast
syringe and inject the contrast as a bolus.

We then follow it with an injection of flush of saline.

Most people, I think at this point would say
that the bolus technique for characterization is essential.

You can't give an infusion as you would
with putting it in saline, for example.

It needs to be injected as a bolus
and then there is a 10 cc flush.

Also, do remember that it is safe to put this stuff
through a PICC line or a central line,
but when you inject through one of those things,
it shows up in the bloodstream almost immediately.

So the timing will be quite different.

Again, if you're going to do repeat injections,
it's important to shake that syringe a little bit.

The patient thinks you're probably losing your mind
as you're standing there shaking this little thing.

But it does help to reactivate.

Just finally, this is a small point,
but it can be really a pain if you can do it.

Put the IV in the left arm.

Most technologists
and machines will scan from the right if,
as was the case in this patient
with a dialysis access graft on the other side.

It has to go on the right.

It just gets really cozy when everybody is there trying
to scrunch around each other, get the scan
and inject at the same time.

So if it's at all possible, try to get
that IV in the left arm.

Dosing and Repeat Injections

Finally, just dose.

If you give too little, you're going
to get a poor contrast image.

If you give too much, remember you may actually get
shadowing from the amount
of contrast in the anterior part of the body.

The doses for each of the agents are different.

The package insert for Lumason will say 2.4.

I think the machines have gotten better.

We typically use about 1.5.

Some specialty areas like breast
and testes may require
what seem like tremendous amounts of contrast.

But if you look at the literature, that's
what people typically use.

As I said, each of the agents has a different dosing regimen,
and we inject, we start the clock
and then we do continuous imaging through the arterial phase
and then intermittently afterwards
because it does tend to preserve the bubbles.

Finally, if you do repeat doses
and it's perfectly fine to do that.

One of the things that may be frustrating is waiting
for the material, the contrast agent to go away.

We typically put on color Doppler.

That is a strong, powerful ultrasound beam
and it breaks the bubbles
and it helps to get rid of that stuff
and clear it out so you can go
and do your repeat injection next.

Conclusion

In closing, this is interesting.

I actually gave a talk
about two months ago in Mexico City.

They have just this month actually introduced Lumason in
Mexico City, the first agent
that's available in Mexico in general,
and this was a drink that was served to me mineral water.

Thank you very much. But for those of you
who don't speak Spanish, I was very pleased when I saw that.

It says now bubbles that last longer. Thank you.