Biliary and Pancreatic Abnormalities on Ultrasound - HD

Introduction

My name is Mark Lockhart.
I'm professor of radiology
and chief of the Body Imaging section at the University
of Alabama at Birmingham.
I'm gonna be talking on biliary and pancreatic ultrasound.
In this lecture, we are gonna cover the indications
for biliary and pancreatic ultrasound,
the technique for ultrasound.
In these areas, we're gonna cover most of our time
with normal structures, benign abnormalities,
and biliary tumors.

Clinical Indications

The clinical indications for right upper quadrant ultrasound
and evaluation of the biliary system in pancreas is most
commonly biliary colic, right upper quadrant pain and fever.
This is when the
clinician is concerned about cholecystitis or cholangitis.
In these cases, there may be a waxing
and waning of the pain over one to three hours.
Another indication is when liver enzymes
or a liver function test are abnormal.
Also, if a patient presents with jaundice
and there's concern for biliary obstruction,
these patients will often be referred to ultrasound
for the normal biliary anatomy.

Normal Biliary Anatomy

The intrahepatic ducts join together
to form the portal radicals, which join together
to form a common hepatic duct at the liver,
hilum a few centimeters.
Beyond that, the gallbladder
and its cystic duct joined to form the common bile duct,
and then the common bile duct joins the pancreatic duct at
the ULA Vadder.
To join into the duodenum, there's a variety
of information in the literature about
normal size criteria.

Normal Size Criteria

Generally, if the gallbladder is less than five centimeters
diameter, this is considered normal.
Also, the gallbladder wall should be less than three
millimeters thick for common duct.
There is some variety in the literature,
but traditionally we've considered
that if the common duct is less than five millimeters in a
person less than 50 years old, that is normal.
And we'll add one millimeter for each decade above 50,
so six millimeters at 60, seven at 70, and so on.
Also, if the patient's head cholecystectomy,
that may enlarge the common duct, an extra millimeter
beyond the expectation.
It should not be considered normal if the common duct is
more than 10 millimeters diameter.
And then there's been some other recent articles
that suggest possibly a seven millimeter threshold
for normal, regardless of age could be considered.

Normal Ultrasound Examples

So here's an example of a normal
ultrasound of the gallbladder.
The wall should be thin.
You've got the normal echogenic surrounding fat,
and the bowel within is koic.
Without layering debris or stones for the common duct,
it may be difficult to see, see the entirety of the length,
but we can usually find a fairly good segment
since it's pretty straight.
You wanna look in the region of the portal vein,
often slightly superficial to that area.
It'll have paper, thin walls
and should be anti coex centrally due
to the presence of bile.
Now on a ct, we can also see it as a circle
of hypo intensity
or hypodensity, again containing the bowel
within the pancreatic head.
This is an example of the cystic duct,
and you can see this circular or spiral type of appearance.
This is due to the spiral valves of heister, which are
commonly seen in this region.

Benign Pathologies

Switching over to pathologies,
we're gonna focus on the benign pathologies.
First, these are gallstones, ductal stones,
gallbladder polyp, acute cholecystitis, adeno, mytosis,
and pancreatitis.
We'll also consider rarer entities such as a colido cyst,
COIs disease, gallstone ileus, and Marzi syndrome.

Gallstones

As our first case, we're gonna start nice and easy.
So we have gallbladder with paper thin walls.
Within it, there are multiple echogenic shadowing foci,
which are mobile, and I think most
of us would be fairly comfortable in easily coming
to the diagnosis of gallstones in this patient.
Now, it may be a little bit harder in a case like this
where you see a layering portion of echogenic debris
and you're not quite sure if this is shadowing from
that layer or not.
Typically we would consider this would be gallbladder sludge
versus sand like gallstones.
In this case, even if it's predominantly sludge,
there's probably a little bit of stone disease mixed in
in these patients.
In this case, we have what's called a wall echo complex
or west sign,
and you can see the echogenic nearfield wall here.
And then there is a dark line between them,
which is the bile in the gallbladder lumen.
And then the second echogenic line,
or the shadow of the west is the front edge
of the large stone with complete shadowing.
Behind this is consistent
with a large gallstone filling the lumen of the gallbladder.
In general, gallstones are round, they're mobile,
they're echogenic, and they're shadowing up
to 80% are cholesterol stones.
And then this is associated with
many clinical situations such as pregnancy,
oral contraceptives, hormone replacement therapy, obesity,
or TPN, Crohn's disease patients can have these
and then also with rapid weight loss.
Here's an example of layering very fine debris,
which is not really a dense layer and there's no shadowing.
So this is one that we would feel pretty comfortable calling
gallbladder sludge.
Now it's just a very thin fine sediment.
They may have the same risk factors at stones,
but this can actually just go away and resolve on its own.
There should not be any shadowing,
even though it may be epigenic.
And then one consideration is that these patients
even if they only have gallbladder sludge,
are at increased risk for developing cholecystitis
or pancreatitis in the near future.
Our next case is showing again, echogenic foci
with shadowing in the dependent portion of the gallbladder.
And we also have gallbladder sludge layering.
As we follow it down, we'll see ductal dilatation
coming in an oblique plane.
And then we have one focal lesion
with shadowing in the common duct.
And again, a little better view
of it highlighted by this circle.
So this is a stone within the common duct,
otherwise known as cholo, dosis.
And this patient also had a ct.
You can see that with contrast.
It may be actually pretty hard to see,
but when we also had the unenhanced CT image,
it becomes much more obvious.
Cholo dosis can result in biliary dilatation.
Often the stone may be echogenic on ultrasound,
but commonly these are not seen by CT
because they're usually not calcified
and you may only be able to see the point of dilatation.
If they're calcified, the unenhanced images can help you
to better see them.

Porcelain Gallbladder

Our next case, so the difference between this case
and the ones that we've seen is notice
that all these echogenic calcifications, they, yes,
they have shadowing, but these are not
all in the dependent wall.
These are on the anterior wall,
they're on the poster wall, they're fairly diffuse.
So this is not typical of your standard stone disease.
And then on this CT of the same patient, we see
that this patient has a classic example
of porcelain gallbladder punctate, linear calcifications.
Again, if you're not thinking it through, you might just say
that these were gallstones adherent to the wall.
It's important to differentiate these those
because porcelain gallbladder,
because it's a chronic inflammatory process, does, has a,
have a significantly increased risk of malignancy,
specifically gallbladder cancer.
Alright, here's another example on this image.
Looking at the gallbladder in a longitudinal plane,
we see this sort of rising moon type of appearance,
round structure, brightly echogenic with shadowing.
So we're saying that there's a gallstone
and now we look at the gallbladder itself
and we see diffuse wall thickening.
Notice you don't want to measure the wall
as it's lying against the liver
because there's some tissues that are very loose in
that region and can simulate wall thickening.
But we do also have this layering sludge in addition
to the stone that I've already shown you.
So when we have gallstones with wall thickening, we want
to check for a sonographic Murphy sign.
But with or without it, we're still going
to be highly suspicious for acute cholecystitis.

Acute Cholecystitis

Now, in this patient we also have a CT
and you can see a dilated irregular thickened gallbladder
with adjacent stranding.
This is just classic cholecystitis no matter which
imaging modality you use.
So again, findings that we'll look for while thickening,
stranding, discontinuous wall enhancement
hyperemia on color, doppler obstruction of the cystic duct
by a stone, and then rarely there may not be any stones
and you may have a situation of a calculus cholecystitis.
Now for a calculus cholecystitis,
we still use wall thickening greater than three millimeters.
We'll also look for we will notice
that there's an absence of gallstones or sludge,
but they may still have the sonographic Murphy sign.
Some authors have suggested
that wall variations may help you.
And then you can also look for a dilated gallbladder,
meaning greater than five millimeter,
five centimeters short axis diameter.
Here's another example where there's no gallbladder stud,
no gallstones, and
yet there's diffuse gallbladder while thickening,
this patient was HIV positive
and this one is consistent with HIV cholangiopathy.
In these patients, they may have pain,
nausea, fever, jaundice.
It has been associated with cryptosporidium.
There are thickening, there may be thickening
of the biliary walls and the papilla may also be emus.

Adenomyomatosis

Another benign abnormality, which we love to show residents
because it's fairly classic is this appearance
of a comet tail
or ring down artifact
where echogenic reflectors from the anterior wall
are mis registered into the gallbladder lumen.
As you see with this circle,
and this is classic for adenomyosis, the ring down is due
to misrepresentation of the depth due to a time delay
as the sound wave reflects
or rattles around in a cholesterol crystal
within the Roku Tansky ash off sinuses.
This way the sound is actually registered in a deeper
location and it's a very clear,
easily identified diagnosis.
There can be focal wall thickening
and in those cases it could raise the question
for a gallbladder cancer.
But again, these should be benign
and we would hope that
they would not have to go to surgery.

Emphysematous Cholecystitis

Now ultrasound can be very hard for this other diagnosis.
So I have an, a nice CT for an example.
When you see this gas filled gallbladder in this,
you can use the lung windows of your CT
to show not only the gas density
but the sloughing of the mucosa and the irregularity.
Please note also this extra luminal collection here
with fluid and gas.
So this is consistent with semus cholecystitis.
It's going to be a complete white out
of the gallbladder since none
of the sound waves can pass through the front wall.
So you're not going to have any of that bile
that would have the west sign for say a large gallstone.
All you're gonna see is one white line completely shadowing
behind and then there may be signs
of pne mobilia within the intrahepatic ducts
to help you with the diagnosis.

Pancreatitis

Okay, switching again.
So this one is a little more focused on the pancreas
and still in that non-malignant category that we're discussing.
So here we have an example of a pancreas,
normal echogenicity.
The head is normal size,
the neck going all the way to the body.
We see a little bit of dilatation of the pancreatic duct
here, but nothing very impressive.
And again, the pancreatic body not as big
as we might be concerned if they had pancreatitis.
Pancreatic tail can be very variable in its thickness
and so that's not very useful to us.
We don't see any of the secondary signs such a collection
or adjacent peri pancreatic fluid.
So in the same patient in the same day, they had a CT scan.
And I'll just draw your attention to this one image
and you can see that same small amount
of biliary dilatation in the pancreatic duct.
But notice this peri pancreatic stranding.
This is a mild case of pancreatitis, which was diagnosed
by CT but missed by ultrasound.
And I do feel that CT is probably our best study
for the evaluation of pancreatitis.

Mirizzi Syndrome

Okay, our next image is showing dilatation
of the common duct measuring 13 millimeters diameter.
So far we know there's biliary dilatation,
but we really don't have a reason why.
As we look at this second image, I'll draw your attention
to the dilate common duct again here,
but look right beside it, there is that sort of rising moon
or classic appearance of a stone lying right
beside the gall, right beside the common duct.
So this is a classic example of Maurizio syndrome
where a stone is wedged in the cystic duct
or a cystic duct stump
and there's a common channel with the common duct,
therefore it will extrinsically obstruct the common duct
and create a biliary obstruction.
And occasionally there may be a gallbladder fistula
to the common hepatic duct in these patients.

Malignant Diseases

For malignant diseases,
we're gonna consider cholangiocarcinoma
and gallbladder carcinoma, biliary metastasis, amary tumor
cystic lesions in the hepatic portions
of the bile duct such as biliary cyst adenoma
or CYS adenocarcinoma, pancreatic adenocarcinoma.
And then IPMN is another lesion
that can occur in this region.

Gallbladder Polyp

Alright, now we're gonna switch over to mass lesions
and we're gonna start nice and easy again.
This is an example of a classic focal small lesion within the lumen of the gallbladder,
slightly protruding inside.
And we put color doppler on.
There's not a stalk of flow,
there's no hyperemia associated with it.
This is your typical appearance of a gallbladder polyp,
echogenic, non-mobile and non shadowing.
These can be adenomatous
or hyperplastic if they're greater than 10 millimeters.
These are worrisome and often these will go to surgery
if they're less than five millimeters
and you do a follow up.
These actually often resolve
and may even be tumor effective sludge
that was misrepresented as a polyp.
Now between the five and the 10 millimeter, we're in
that borderline zone that most people will get a follow up
at six months and then maybe even a year later after that
because there's a risk
that you may be finding an early gallbladder
cancer in these patients.

Cholangiocarcinoma

Now this is a little more worrisome.
This is a focal mass in the junction region
of the biliary radicals.
It's mildly echogenic
and it has biliary obstruction of both sides associated
with this and this one on the video shows
how this tumor is protruding into those ducts.
And this is a typical central cholangiocarcinoma,
otherwise known as a clat skin tumor.
Now a peripheral cholangiocarcinoma on ultrasound is going
to be focal near the periphery
and on CT it will be hypodense on the pre contrast
with a slow progression of the central stroma
with potentially a small capsular rim sign
as we see on this one.
The key in these is in 36
to 70% you'll actually have increased density on the delayed
images of the ct.
The peripheral, in my experience,
are less common than the central
or the clat skin type tumors.
Cholangiocarcinomas are more common in elderly patients
and they may present with painless jaundice.
Other risk factors include primary sclerosis
and cholangitis chodo cyst,
Caris disease pair parasites within the biliary tract
or previous tho contrast exposure.

Gallbladder Carcinoma

Here's another focal mass sort of in that liver hilum,
but notice there's not really the associated biliary
dilatation that we were seeing with the clat skin tumor.
And then as you can see right here, there's a little bit
of fluid and this is going
to actually turn out to be the gallbladder.
Here's an MRI that was subsequently obtained
and we see gallstones within the gallbladder
and an eccentric focal mass,
which is actually invading into the liver
parenchyma from the gallbladder.
And you can see on these T two weighted images, the edema
and the high T two signal associated with
this extrinsic mass coming out of the gallbladder wall.
So this is consistent with the gallbladder carcinoma.
Here's another example.
So we have a focal polyp within the gallbladder
and then a second larger hyper enhancing mass,
which is not only protruding into the gallbladder
but also extending out.
And you can see there are multiple gallstones
also associated with this patient.
Now gallbladder carcinoma can be infiltrating in about two
thirds or polypoid in about one third.
If you use a contrast agent,
it'll be bright on the arterial phase
and may retain contrast on the portal phase.
And then you should look for liver mets or direct invasion
because these can be quite aggressive.
They occur in elderly females,
they're usually in adenocarcinoma.
And then they've been associated with either gallstones,
porcelain, gallbladder, primary sclerosis and cholangitis
or chodo cyst.

Gallbladder Metastasis

This is our next case. And you can see a focal polypoid
lesion on ultrasound in the gallbladder.
Again, it's a little dark,
but you can still see the eccentric nodule lesion
and there was a little bit
of low resistance arterialized flow on the color
and spectral doppler.
This patient went on to CT
and we can show clearly
that it's not a stone on the unenhanced images.
And as we give contrast we see bright arterial phase
enhancement and then early washout.
Now I've withheld a little information from you
because this patient had a known melanoma
and this turned out to be a metastasis from melanoma.
If you're looking at gallbladder metastases,
melanoma is the most common primary source
and if they have multiple hepatic lesions
where you're not really sure that they have melanoma,
it can look like other types of metastatic disease
or even metastatic cholangio carcinoma.

Ampullary Tumor

Here's another example of a malignancy.
So we start with the ultrasound
and we see diffuse severe biliary dilatation,
central intrahepatic and common duct dilatation
and we can put color on to make sure
that this is not a vessel that we're seeing.
As we go through here.
I'll just show you how this biliary dilatation not only is
intrahepatic, but goes all the way down as far
as we can follow it toward the pancreatic head.
On the CT there is diffuse biliary dilatation
and this shows you that it's not only within the common duct
but the pancreatic duct is also dilated as well.
And then we can see how this comes down
to a focal lesion in the distal common duct, which then sort
of blends into this focal soft tissue mass
in the amary region.
So this is a amary tumor.
You'll often see the double duct dilatation
to the level PUIs, such as you might see
with a pancreatic adenocarcinoma.
CT really has poor sensitivity
and ultrasound's not that great either
for finding a small amary lesion.
Now it may see the biliary dilatation
and the pancreatic duct dilatation that's associated
with it, but actually identifying the lesion when it's small
can be difficult and may require endoscopy to detect.

Pancreatic Adenocarcinoma

Here's another example.
Severe pancreatic duct dilatation
coming into this poorly defined hypo coic mass like region
in the pancreatic head, putting nice little calipers here.
Really let you see where that is relative
to the adjacent structures.
And then there's some dysmorphic vascular flow once we see on a color doppler.
This turned out to be a pancreas adenocarcinoma.
These are often infiltrative hypodense.
You may see if you do a good pancreas arterial parenchymal phase, it'll be hyper hypodense relative
to the surrounding parenchyma.
In portal venous phase, we can evaluate for invasion
or involvement of the SMV splenic vein
and portal confluence.
We're gonna also look for direct invasion into other organs,
nodal disease, and then distant metastases.

Chronic Pancreatitis Mimicking Tumor

Now after showing you that last one on ultrasound,
I'm gonna show you one that looks exactly the same.
Here we have a poorly marginated infiltrative
hypoechoic mass within the pancreatic head.
You look at this image and you are thinking cancer.
So we look and we see, okay,
I've already told you this is not a tumor,
but we see pancreatic duct dilatation going into
this hypo coic mass.
And look at this all through here.
Now one hint might be these echogenic shadowing structures
within the pancreas parenchyma,
but again, my sonographer shows me this image
of an infiltrative hypo coic lesion.
I'm thinking tumor all the way.
So this patient had an MRI
and I'll draw your attention to several different points.
Here's your cystic changes.
There's little side branch dilatation.
Pancreatic head is irregular
and we've got a focal high intensity
signal lesion right here,
which is gonna be consistent with a stone.
And then as we see the pancreatic duct dilatation,
I don't know how well you can see it,
but there's small side branch areas
of dilatation throughout this pancreatic body and tail.
So this is actually chronic pancreatitis,
but it was a very mass like appearance of it.
There was the irregular ductal dilatation, focal hypoechoic,
not anti coic collection,
which looked all the world like a tumor.
If you're able to see the side branch dilatation by CT
or MRI, you might suggest the diagnosis.
And then again, if you see those echogenic shadowing stones
within the pancreatic duct, you might think, well,
maybe this person's had recurrent pancreatitis,
therefore the cal calcifications.
And then you might be able to sort
of think about something other than tumor in this case.

Conclusion

Well, that's sort of a whirlwind tour through the
biliary system and pancreatic abnormalities
by ultrasound With a little bit of correlation, I hope
to point out that for many biliary
and pancreatic abnormalities,
ultrasound can make the diagnosis
and then also ultrasound can help you differentiate
benign from malignant disease.
Thank you for your attention.