Imaging the Patient with Acute RUQ Pain - SD

Introduction

Good day.
My name's Tony Hage.
I'm an abdominal imager at the University of Toronto,
and today I'm going to present a talk
on a common everyday condition.
The patient from the emergency room
with acute right upper quadrant pain
imaging the patient with acute right upper quadrant pain,
acute abdominal
and pelvic pain is the most common presenting symptom
to our emergency departments in North America today.
Accounting for approximately 7% of all such visits,
right upper quadrant pain is a common
and important subset of these patients,
but finding the exact cause is a clinical challenge.
Generally after the initial assessment, the gallbladder
and bile ducts emerge as prime suspects.
But diagnosis based on the clinical assessment
and simple laboratory tests is frequently inaccurate.
So imaging is critical to management.
Ultrasound should always be the initial imaging test
for these patients.
It's accurate, safe, inexpensive, available,
and portable and indeed can be performed at the patient's
bedside in the emergency department.

Learning Objectives

So our learning objectives for this presentation are
to discuss the value of ultrasound
in assessing the patient
with acute right upper quadrant pain.
We will identify the imaging features of acute cholecystitis
and its complications,
and we'll describe other conditions
that can cause acute pain in the right upper quadrant when
the gallbladder is normal.

Acute Cholecystitis

Now we're all very familiar
with the requisition from the emergency room physician,
rule out acute cholecystitis,
but in fact, less than half
of these patients will in fact have acute cholecystitis
or its complications.
And there's a whole array of other conditions
that can mimic such as choledocholithiasis
and ascending cholangitis,
recurrent pyogenic cholangiohepatitis, liver abscess
and rupture with hemorrhage of liver masses to name some.

Now the ultrasound appearances of
acute cholecystitis have been well described
and ultrasound has an accuracy of approximately 88%,
which is similar to scintigraphy.
But ultrasound has advantages such
as identifying complications of acute cholecystitis
or offering alternative diagnosis if the
gallbladder is normal.
Scintigraphy is also more time consuming.

Now 90 to 95% of patients
with acute cholecystitis will have gallstones.
The stones cause obstruction of the gallbladder neck
or cystic duct.
Variable degrees of infection
and necrosis ensue as the gallbladder distends
patients present with right upper quadrant pain,
tenderness and guarding.
And there's a whole spectrum of
clinical presentations from mild to quite dramatic.

The most sensitive combination
of sonographic findings are maximal tenderness over the
sonographically localized gallbladder in the presence
of gallstones and pericholecystic fluid.

Rumack had a paper published in radiology in 1985,
which showed a positive predictive value of 92%
for this combination of findings.
In a prospective study of almost 500 patients,
gallbladder distention, diffuse wall thickening
and pericholecystic fluid are secondary findings
that are neither sensitive nor specific.

But I'd like to draw attention to gallbladder distension
and share with you our first teaching pearl for today,
and that is to be reluctant
to diagnose acute uncomplicated cholecystitis if the
gallbladder is not tensely distended.

Here's an example of a middle aged woman from the emergency
department with acute right upper quadrant pain.
We identify gallstones, we slide the probe down,
the patient is maximally tender over the sonographically
localized gallbladder.
Note that the gallbladder is tensely distended.
Note also that the gallbladder wall is not particularly
thickened, but the combination
of findings here in this clinical context are highly
suggestive of acute cholecystitis.

Another teaching pearl is in these patients pay particular
attention to the region of the gallbladder neck
and cystic duct looking for the obstructing stone.
And if you uncover such a stone, it will add confidence
to your diagnosis
and make you even more secure in strongly suggesting acute
cholecystitis as the cause of the patient's pain.

Here's another example.
With a similar clinical history,
we see stones in the gallbladder lumen.
The patient was maximally tender over the sonographic
localized gallbladder.
The gallbladder is tensely distended
and in this case there is wall thickening
with an edematous gallbladder wall.
Once again, pay attention to the region
of the gallbladder neck and cystic duct.
And in the same patient now using a
different acoustic window.
We've moved the probe up and are scanning intercostal.
We've unfolded the gallbladder neck
and uncovered the obstructing stone.
So once again, this adds confidence to the diagnosis.

Another teaching pearl relates to the fact
that most gallbladders today are removed laparoscopically.
And whether we're imaging the gallbladder in an acute
or an elective setting,
we must always remember the possibility
of underlying gallbladder cancer as most surgeons
feel that they would be much better
prepared if they are aware of the possibility
of an underlying gallbladder cancer
before the gallbladder is removed through the laparoscopic ports.
And the reason for this is there is a propensity
for gallbladder cancer to recur at the laparoscopic ports
if proper precautions are not taken.

And here's an example, three months post
elective cholecystectomy.
There was an underlying unsuspected gallbladder cancer
and we can see recurrence at the right upper quadrant port
site and the umbilical port site in this patient.

So when this retired obstetrician presented to me
with acute right upper quadrant pain, I did this ultrasound,
we documented gallstones.
There was maximal tenderness over the sonographic
localized gallbladder.
The gallbladder wall is thickened,
the gallbladder is distended.
So I felt quite comfortable
that there was acute cholecystitis,
but this additional echogenic material within the gallbladder lumen caused me
some concern as I didn't want to overlook the possibility
of an associated gallbladder cancer.
And in this case, I recommended a CT scan to help clarify.

And on the CT scan,
we see some high attenuation within the gallbladder lumen,
which was present on the unenhanced images
and simply represents the gallstones.
Following contrast, we can see enhancement
of the gallbladder mucosa.
It looks thin and smooth.
There's a small breach in the mucosa,
which suggests early gangrenous change,
and then we see quite marked pericholecystic inflammatory change.
So I was quite satisfied
that all the findings here could be explained on the basis
of inflammation, I didn't see an enhancing tumor mass
and she went on to have a non-eventful cholecystectomy,
which confirmed the diagnosis.

Gangrenous Cholecystitis

That brings us on to gangrenous cholecystitis,
which can occur in up to 20 to 38%
of cases of acute cholecystitis with ultrasound.
Look for asymmetric thickening of the gallbladder wall.
Look for intraluminal membranes.
Remember that as the gallbladder undergoes necrotic change, the sonographic Murphy sign may become
negative in up to two thirds of patients and the symptoms
and signs shift away from the right upper quadrant.

This is such a case.
A patient presented with abdominal pain for a week.
The pain was somewhat nondescript.
It was a concern regarding urinary tract calculi.
So this unenhanced renal colic CT scan was performed.
The urinary tract was unremarkable,
but on these slightly narrowed windows,
we can see a fairly distended gallbladder
with a high attenuation linear line within
the gallbladder lumen.
This raised our suspicions of gallbladder pathology
and as is appropriate, an ultrasound was performed,
which showed a distended gallbladder
with a fluid debris level
and sloughing of the mucosal membranes
and asymmetric wall thickening.
We made a diagnosis of gangrenous cholecystitis,
which was confirmed at surgery.

Perforated Cholecystitis

Now here's another case.
CT was performed on this occasion
to rule out a bowel obstruction in a patient with
vague and indeterminate abdominal pain.
And I was working with a very good fellow on this particular day who said to me,
this patient doesn't have bowel obstruction,
this patient has acute cholecystitis.
And I immediately said, not so fast
this gallbladder is not tensely distended.
And when we look more closely at the gallbladder fossa,
we can see the gallbladder,
but in fact there's a second cystic collection in the gallbladder fossa.
And when we analyze the images more closely, we realize
that this gallbladder has perforated
and has actually decompressed and is
therefore not tensely distended.
And there is now the formation of a pericholecystic abscess.

So how common is gallbladder perforation?
Well, it occurs in five to 10% of all cases
of acute cholecystitis.
And it's an important condition
because it carries a significant mortality rate of 19
to 24%, if not promptly treated.

There are three types.
It can be acute where it happens very abruptly
and you get a very generalized peritonitis.
It can be subacute where the inflammatory
processes walled off by the greater omentum.
And a pericholecystic abscess forms or a more chronic type
where the inflammation is more indolent
and other structures may stick on
to the gallbladder such as the duodenum or the colon.
And an internal biliary fistula may form
to these structures.
The most common type is the subacute type
where pericholecystic abscesses form.
And the most common site
for perforation in the gallbladder is towards the gallbladder fundus.

So here's an example.
A patient with a one week history
of abdominal pain and fever.
We see a large stone in the region
of the gallbladder neck,
but note that the gallbladder is not tensely distended.
And when we look in the region of segment five of the liver,
there's another complex cystic mass
looking more closely at that mass.
It has the appearance of a liver abscess in this patient
with right upper quadrant pain and fever.
And when we return
and look a little more closely at the region
of the gallbladder
and analyze the gallbladder itself in more detail,
we can actually identify the site of perforation
with abscess developing in the adjacent liver.

Again, on these patients,
our interventional radiologists like a CT scan
to better show the full extent of abscess formation.
And here the CT nicely confirms the
sonographic findings.
And if we look more closely again at the gallbladder,
the CT also shows the site of perforation
and the literature tells us that ultrasound
and CT are equally sensitive in this regard at documenting the site of perforation.

Emphysematous Cholecystitis

Now, what about emphysematous cholecystitis?
A rare but important condition caused
by gas forming bacteria
gallstones are often absent
and many patients are diabetic about 38%.
So it's a condition that also occurs in non-diabetic patients, more common in men than women,
and an important condition
because of the much higher gangrenous
and perforation rates with their associated higher morbidities and mortality.

Here's an example, the best view we could get
of the gallbladder.
And here we see a very echogenic
curvilinear line corresponding with the gallbladder wall.
Difficult to say with certainty from that appearance,
whether that's calcium or gas,
but the reverberation artifact from the wall is very
suggestive of gas.
So this appearance is highly suggestive
of emphysematous cholecystitis that is easily confirmed
with a CT scan performed the same day showing gas in the
gallbladder lumen and the gallbladder wall.

So this is an important condition that requires rapid treatment to cut down on the morbidity and mortality.

Now, how does that appearance compare with
the appearance on the image on your right where we see
an echogenic line, which is the gallbladder wall
and then a second echogenic interface,
which are stones filling the gallbladder lumen.
And then we get a very clearly defined dark shadow typical
of the shadowing we see from calcification.
So this is how we distinguish a gallbladder filled
with stones from emphysematous cholecystitis,
and this appearance on the right is known
as the wall echo shadow complex or the WES complex.

Porcelain Gallbladder

And that brings us to a third case.
On your immediate right,
what does this appearance represent?
And when we analyze this image, we can see that the wall
of the gallbladder here really is indistinguishable from the
appearance of the air
and the gallbladder wall in the initial case,
which I showed you.
But the teaching point is that the truth lies
with the shadow and the shadow is the shadow we see
from calcification.
So this is a calcified gallbladder wall
or a porcelain gallbladder, which was confirmed
with CT.
And this condition has been associated
with a much higher rate of development
of gallbladder cancer.
So certainly in younger patients,
porcelain gallbladder may be a reason for cholecystectomy.

Other Gallbladder-Related Conditions

Now here's another older patient that was an inpatient in
our hospital who presented with right upper quadrant pain.
These are the best images of the region
of the gallbladder fossa.
And these images show a large calcification
or large stone in the region of the gallbladder surrounded by
hypoechoic likely soft tissue thickening.
And in the context of pain
and fever, we interpreted this
as more likely an inflammatory mass
with a gallstone than a neoplastic mass.
The patient returned to the floor,
was treated conservatively,
and the surgeon came to speak to us a couple of days later
and told us that the character
of the patient's pain had changed, had become more diffuse,
and that the abdomen had become distended
we felt a CT scan might offer additional information.
And on the CT scan we can now see gas within the gallbladder lumen.
There's pneumobilia.
And when we look at the bowel, we can recognize
that the large stone
that was within the gallbladder has now migrated
through a fistulous communication with the duodenum
along into the small bowel with associated bowel wall thickening.
So this is now a gallstone ileus accounting
for the patient's symptoms.

Here's another example of gallstone ileus
where we can identify dilated bowel loops
with air fluid levels.
We notice the gallbladder lumen filled with gas
and the CT nicely shows the fistulous communication with the duodenum
and the obstructing stones in the distal ileum,
which is the most common location
for obstruction in this condition.

Here's another patient who presented
with projectile vomiting and abdominal pain,
and the image on your left is the best view we could get
of the gallbladder fossa.
We had an appearance there, we felt of gas within the region
of the gallbladder fossa.
We couldn't confidently identify stones,
but immediately adjacent
to the gallbladder was this peristalsing fluid-filled
tubular structure with a stone.
And again, we suspected
that perhaps there was a high GI obstruction
from a migrated gallstone.
So we recommended a CT scan to further investigate this possibility.
And here we can see a stone within the duodenum
and more distally, a second stone
obstructing a proximal jejunal loop.
And when we go back we can see gas within the gallbladder
lumen and in this case a fluid-filled fistula communication with the duodenum
and of course, a stone obstructing.
The duodenum that has migrated from the gallbladder is known
as Bouveret syndrome.

Gallbladder Torsion

Another condition that's very rare
but maybe becoming more common is gallbladder torsion.
It occurs in fragile elderly patients.
The majority are women.
It's a difficult diagnosis because it is uncommon
and it comes in two varieties, an incomplete torsion
or a complete torsion,
and only the minority of patients have stones.

Here's an example.
The ultrasound on your left was performed in a 94-year-old
patient with abdominal pain
and we identified the cystic structure,
which was actually down overlying the bifurcation
of the aorta.
It has an edematous wall,
but we didn't actually establish that it was arising from
the gallbladder fossa.
We did assess it with color doppler.
There was no flow within it,
it was only when the CT scan was performed
that we actually recognized this structure had a neck
arising out of the gallbladder fossa with some beading.
And when we carefully analyze the axial images,
we can see the cystic artery here with some torsion
of the gallbladder neck around the artery
and incomplete torsion with a twist
of approximately 180 degrees.

Pitfalls and Mimics

Now what about pitfalls and mimics?
Well, here's a young woman
with acute right upper quadrant pain
and we can see the white arrows outlining a very markedly
thickened and edematous gallbladder wall.
The patient was fairly diffusely tender in the right upper
quadrant, but note
that this gallbladder is not tensely distended.
In fact, the lumen is almost completely obliterated
and we could not see any gallstones.
We also look at the periportal triads
and we note periportal edema.
It got us to check the patient's clinical chart
and of course the transaminases were markedly elevated.
So this patient has acute hepatitis.
It's always important to know your patient.
It's important to go speak to the patient
and review their charts so that you interpret these studies
with the full complement of available clinical information.

The image on your left is another older patient
with a slightly distended gallbladder but no stones.
The gallbladder wall is edematous.
There's pericholecystic fluid,
and the clue in this case lies in the inferior vena cava, which is quite distended
as were the hepatic veins.
And the liver margin looks a little bulbous.
So this is a congested liver from heart failure
with secondary changes in the gallbladder
or the case on the right
where we see also an edematous gallbladder wall, there is a soft stone
or a sludge ball within the gallbladder lumen
with a lot of free fluid.
And this patient of course has liver cirrhosis.

This case is also an informative case.
This was a woman again in her thirties with acute upper abdominal pain.
There's a stone in the region of the gallbladder neck.
The patient was quite acutely tender in the upper abdomen,
but I would suggest to you
that this gallbladder is not tensely distended.
And in fact, if you look at the margin
of the gallbladder adjacent to the liver,
it has a concave appearance internally rather than convex externally.
So this prompted us to go in again
and see the patient take a history
and do a very careful sonographic evaluation
where ultimately we saw this focal enhancement
of the peritoneal stripe in the right upper quadrant
overlying the liver
with the patient lying left posterior oblique.
And you'll notice that this focal enhancement exhibits some reverberation artifacts suggesting free air
confirmed at CT scan where we see an inflammatory process in the right upper
quadrant with the free air from a perforated duodenal ulcer.
And in fact, the gallbladder is inflamed here,
but it's secondarily inflamed from inflammation tracking up
to the duodenhepatic ligament rather than primarily inflamed
from an obstructing stone in the gallbladder neck.
So perforated duodenal ulcer mimicking acute cholecystitis

or another example of a patient
with acute right upper quadrant pain
where the gallbladder is somewhat distended,
but there were no gallstones.
There is some pericholecystic fluid again, prompted us to go
and see the patient show us exactly where the tenderness was, which was in fact
a slightly inferolateral to the gallbladder.
And when we examined this area,
we noted some focal thickening of the hepatic flexure
of the colon with a surrounding inflammatory mass
and inflamed diverticulum, which had perforated
with this track of extraluminal gas.
So acute diverticulitis of the hepatic flexure
of the colon.

Other Conditions Mimicking Acute Cholecystitis

Let's leave the gallbladder now
and go on to talk about other conditions
that can mimic the presentation of acute cholecystitis.
And we'll start with choledocholithiasis.
And depending on the laboratory,
there are varying sensitivities for ultrasound with choledocholithiasis,
but 70% sensitivity is probably
a good conservative estimate if the ducts are dilated.
This will improve the detection
and some advances in technology over the years, such
as harmonic imaging may also improve detection.

To examine the CBD in its entirety
can be quite difficult to see the distal CBD sometimes maneuvers such
as setting the patient partially upright
and turning the patient right
posterior oblique may be beneficial for the proximal amid CBD.
It can often be well seen with the patient supine
or left posterior oblique.
And even the distal CBD can often be seen
with the patient supine if you use compression
to move gas out of the duodenal loop.

Here's an example of a patient who presented to emergency
with acute right upper quadrant pain.
The liver functions were notably abnormal.
The intrahepatic bile ducts are markedly dilated.
It's really important to follow these ducts centrally do they all communicate, and in this case they did
and entered a markedly dilated common bile duct.
Again, your job isn't complete.
You must follow the dilated bile duct to establish the level
and hopefully the cause of obstruction.
And in this case, we see a large gallstone
as the cause of obstruction.
Some of you are probably saying, well,
for such a large stone it really doesn't exhibit all
that much shadowing.
And it's important to note that this image was taken
with sonography.
So there are many angles of insonation dispersing the shadow as a result.

Now if you suspect there may be a stone in the common
bile duct, but you can't actually find it with ultrasound.
In other words, you see biliary dilation, you can follow it
to the CBD, but the distal CBD is obscured
and you can't actually establish the level
or cause of obstruction.
And if in your department you have difficulty accessing MRI
in an acute setting, CT is a very good option.
And here is such a patient where at the level
of obstruction we can see some high attenuation
within the CBD.
Now the problem with this image is
that intravenous contrast has been administered,
and it's impossible to say if this obstruction is caused
by a stone or enhancing soft tissue.
So if you're going to look for a stone with CT,
the teaching point is
that you must include an unenhanced series.
As we see here, the stone is now visible,
so when protocoling these cases, it's critical
to include a non-enhanced series.
But MRI obviously is very sensitive
and specific for stones if you do have access
to a magnet in the acute setting.

Now, other things within the common bile duct can cause pain.
Here is a patient who on day one had a transjugular liver
biopsy and returned to the emergency room
on day three with acute right upper quadrant pain.
Sonographic images show blood within the gallbladder lumen.
And on careful assessment of the CBD,
we see echogenic material.
So this patient has bleeding post biopsy
with blood in the gallbladder
and hemobilia as a cause of biliary colic

or another older case,
but a case worth keeping
where the image on the left was taken at 8 AM in the
morning and shows a linear structure within the CBD.
There was no history of intervention in this patient.
And a follow up image taken
an hour later shows a completely normal CBD.
So what was this linear structure?
Well always consider the possibility
of a parasitic infection in this case, Ascaris lumbricoides
as a cause of the patient's biliary colic.

Here's another patient.
This patient had a history of jaundice
for about three weeks,
but was brought to the emergency room on the morning
of this ultrasound scan
with acute right upper quadrant pain.
This was the best image I could get of the bile ducts
and CBD, which are clearly dilated.
And then there's this large cystic structure more distally.
And initially I was wondering about the possibility of some type of choledochal cyst,
but another important teaching point if you ever see a
cystic structure with ultrasound always put on doppler
and what a surprise I got when I realized
that this was a large aneurysm
or pseudoaneurysm obstructing the CBD.
We brought the patient immediately for a CT angiogram
confirming this large aneurysm of the hepatic artery.
And you'll notice as we scan
through this aneurysm is now quite irregular in shape,
which in combination with the history
of acute pain likely reflects impending rupture.
And this patient was taken fairly immediately
to the operating room for a successful repair.

Ascending Cholangitis

Ascending cholangitis, often a clinical diagnosis, patients
with pain, fever, high white cell count,
abnormal liver function, these patients can be very ill
and ultrasound is important to look
for a treatable biliary dilation
and may also show thickening of the wall
of the bile ducts.
It may also show an obstructing cause such as a gallstone
and of course can be very helpful for guiding intervention.

Here's an example where we see the CBD in transverse
with a markedly thickened hypoechoic wall in a patient
with ascending cholangitis

or another elderly patient who presented in septic shock
to our emergency room.
We did this ultrasound quite urgently.
We can see the portal vein highlighted here
with a very dilated CBD anterior to the portal vein
filled with echogenic material, a combination
of soft stones and sludge.
So if you see a very ill patient
or even not such a very ill patient
and you confidently identify stones
or a stone in the CBD
on ultrasound, those patients can go directly
for definitive treatment with ERCP once they've been
resuscitated with intravenous fluids
and given appropriate antibiotic coverage.

And here's that patient who went to ERCP,
confirming the stones
and sludge within the lumen.
Again, the teaching point go directly
to ERCP if you identify the stone
with ultrasound.

Recurrent Pyogenic Cholangiohepatitis

Recurrent pyogenic cholangiohepatitis,
another important condition common in Asia,
although we also see a large number of cases
of this condition in Toronto felt
to be associated with the liver
fluke Clonorchis sinensis
patients develop soft intrahepatic biliary stones.
Segments most commonly affected are segments two
and three of the left lobe and then segments six
and seven of the right lobe.
The hallmark of this condition is associated atrophy of liver parenchyma in the affected segments
because of the recurrent inflammation
with hypertrophy of the parenchyma in the healthy segments.
The definitive treatment is surgical.

Here is a typical ultrasound appearance,
a sagittal image of the right lobe where we see soft stones
with vague
posterior shadowing involving the segment six intrahepatic bile ducts.
These stones are easily overlooked
because of the associated parenchymal atrophy
as the portal triads
and affected bile ducts migrate to the capsular surface
of the liver with hypertrophy
of the healthy liver replacing the
atrophied segments.

Here's a different patient with two images.
Again, a sagittal image
through the left lobe shows disorganized liver parenchyma.
It's quite a difficult image to interpret.
There may be a stone centrally.
And then an image of the right lobe showing
intrahepatic biliary stones in bile ducts
that are close to the liver surface.
And then we look at a non-enhanced CT scan on this patient.
And we can very nicely see here the intrahepatic
biliary stones in segment six sitting right on the
capsular surface of the liver
because of the marked atrophy of the involved segments.
And then hypertrophy of the healthy segment five
and eight replacing the atrophied liver parenchyma.

Liver Abscess

Liver abscess can be pyogenic or amebic.
Patients present with pain
and fever can mimic the clinical presentation of acute
cholecystitis with pyogenic abscesses.
No underlying cause can be established in about 50%
of patients and these are often anaerobic abscesses
in the remaining 50%
where an underlying cause can be determined.
The bile ducts are the most likely cause
with the gut either acute diverticulitis
or acute appendicitis in second place.
But infection can spread from other parts of the body,
osteomyelitis
or infective endocarditis.
The treatment for liver abscess,
it's generally image guided percutaneous drainage.

Here's an example, large abscess in the right lobe
of the liver with a very typical appearance with cystic
and solid components.
And this should pose no difficulty at all
for diagnosis in the right clinical context.

But here's another patient with similar symptoms
of pain fever, malaise.
We see a large mass in the right lobe of the liver,
but in this case the mass appears much more solid
And it's important to realize that with ultrasound,
early liquefaction can have a solid appearance.
Here we see the CT scan from the same day showing
early liquefaction.
So ultrasound can be misleading
and given appearance of a solid mass when in fact
what one is dealing with is a liver abscess.

Ruptured Liver Masses

Now finally, we'll briefly discuss masses
that rupture and bleed.
And these masses of course cause
acute pain in the right upper quadrant.
The main culprits are hepatic adenoma
and hepatocellular carcinoma,
although other masses can bleed.
The important way to distinguish
between the first two is know your patients.
So the patient profile adenomas most often occur in
premenopausal women on the birth control pill,
whereas hepatocellular carcinoma occurs in patients
who have known chronic liver disease are most often
cirrhotic and often have chronic hepatitis
C or B.

So here's a young woman with a 10 year history
of taking the birth control pill.
On the unenhanced image we see hemoperitoneum
with a suggestion of a large mass in segment two that mass looks irregular.
It has a large cleft within it
and at surgery of course had a ruptured adenoma.
The adenomas that bleed briskly
and cause problems with hypotension
and shock are generally the lesions that are subcapsular
and rupture freely into the peritoneal cavity.

Here's another patient
with a similar history presented acutely
to the emergency room with pain and a drop in hemoglobin.
We see this large heterogeneous mass exophytic from segment
five of the liver,
an acute blood clot over the liver capsule.
This patient had a 20 year history of chronic hepatitis,
so this is hepatocellular carcinoma
that is spontaneously ruptured and bled.

And finally, a woman in her forties
who was also on the birth control pill,
presented one Saturday night to our emergency room
with acute upper quadrant pain
and a drop in blood pressure
Ultrasound showed a large mass in the right lobe
of the liver, very heterogeneous mass.
CT confirmed the mass
with high attenuation centrally suggesting blood within the mass
and some hemoperitoneum which extended to the pelvis.
And we anticipated
that this too would be a hepatic adenoma,
but we were surprised when we gave contrast on CT to see the
typical peripheral nodular enhancement
of a large cavernous hemangioma.
And this was confirmed at surgery.
This was a large spontaneous bleed
in a cavernous hemangioma which can occur
but is extremely rare if hemangiomas bleed.
It's usually as a result of minor trauma
or during pregnancy.

Summary

So that brings me to the end of the presentation.
To briefly summarize our teaching points
from today's talk.

First of all, be very slow to
diagnose acute uncomplicated cholecystitis.
If the gallbladder is not tensely distended,
at least slow down.
Have a very careful conversation
with the patient about their symptoms
and evaluate the patient very carefully
with ultrasound in the area of maximal tenderness.
'Cause it may be that there is another cause
for the patient's pain.

Remember, in cases of acute cholecystitis
to spend additional time looking
for the obstructing stone in the gallbladder neck
and cystic duct, as this will add confidence
to your diagnosis.

Remember, when you're imaging the gallbladder to always look for underlying gallbladder cancer,
as this is critical information for the laparoscopic surgeon
and they will appreciate being forewarned if you do have a
suspicion that there may be an
underlying gallbladder cancer.

Remember when distinguishing air from calcium,
the answer lies in the shadowing reverberation artifact
with air clean shadowing from calcium.

Remember that if you identify a stone
in the CBD on ultrasound, there's no need for MRCP.
That patient can go directly to ERCP
for definitive treatment.

Remember that if you don't have access
to MRCP when you suspect
that there may be a stone in the CBD on ultrasound,
but you're unable to demonstrate it
because of limited visibility, you can use CT.
But if looking for a stone on CT,
you must include an unenhanced scan.

Remember, anywhere in the body if you see a cystic mass,
it's worth interrogating that cystic mass
with doppler ultrasound as every so often
you will uncover an unsuspected aneurysm.

Remember that abscess may appear solid on ultrasound in its
early stages, and in this situation,
CT with contrast is helpful
to demonstrate early liquefaction.

And finally, if giving a differential
for a liver mass that has ruptured and bled
that a differential is best based on the patient's profile,
a woman on the birth control pill most likely
to be a hepatic adenoma, whereas a patient
with chronic liver disease
and cirrhosis most likely
to be hepatocellular carcinoma.

Thank you very much.