Ultrasound Imaging of Complicated Inflammatory Gallbladder Disease - HD

Introduction

Good afternoon.

My name is Catherine Robinson. I'm an assistant professor in radiology at Mallinckrodt Institute of Radiology in Washington University, St. Louis, Missouri. Today I'll be speaking on ultrasound imaging of complicated gallbladder disease.

Learning Objectives

The learning objective today will be to discuss the sonographic findings in complicated inflammatory gallbladder disease.

We will cover complicated cholecystitis including gangrenous cholecystitis, emphysematous cholecystitis, hemorrhagic cholecystitis, perforated cholecystitis, acalculous cholecystitis and xanthogranulomatous cholecystitis, as well as gallbladder cancer and porcelain gallbladder complicated cholecystitis.

Overview of Complicated Cholecystitis

We know that 90% of patients with acute cholecystitis result from a stone obstructing the cystic duct when there is prolonged cystic duct obstruction. This results in complicated cholecystitis.

It is important for radiologists to be familiar with complicated cholecystitis as it occurs in up to 30% of cases of acute cholecystitis. In addition, the morbidity and mortality from complicated cholecystitis is as high as 9% pathologically with complicated cholecystitis.

The prolonged cystic duct obstruction results in increased intraluminal pressure, which causes mucus production and distension bile salt concentrate. And there's resultant chemical inflammatory reaction, which causes neural infiltration, vascular compromise, necrosis and perforation.

Complicated cholecystitis encompasses a range of pathologic inflammatory disorders that we've described. One approach to complicated cholecystitis is to look at changes that can occur in the gallbladder lumen. In the gallbladder wall or in the pericholecystic space.

Gallbladder Wall Necrosis

Illustrated is gallbladder wall necrosis. We see linear echogenic line paralleling the gallbladder wall on transverse images. It appears as if you took your hand and the pulled the mucosa, so the mucosa is being pulled off of the gallbladder wall. In this undulating appearance, the patient on the right presented with right upper quadrant abdominal pain and an ultrasound. All we saw was this linear echogenic line paralleling the gallbladder wall. There was concern based on this image for gangrenous cholecystitis.

Now, differential considerations for disappearance include inspissated mucus, but oftentimes the strands can be randomly oriented with inspissated mucus or multi septate gallbladder, which is a congenital anomaly that results in multiple septations within the gallbladder. In multi septate gallbladder, the septate are perpendicular to the gallbladder wall.

We will come back to this case in a few slides.

Mural changes that can occur with gallbladder wall necrosis include focal ulcerations in the gallbladder wall, focal disruptions in the gallbladder wall, loss of the normal gallbladder wall. Ano reflexivity a focal bulge in the gallbladder, which can symbolize or represent a localized perforation.

In all of the patients listed in these images, there was a gallbladder wall necrosis at surgical pathology and we can see the focal ulceration disruption loss of normal sonal reflexivity of the gallbladder wall.

I show you this image to stress the importance of technique. This patient was a patient who presented with findings of acute cholecystitis. There was sludge and stones in the gallbladder. All the images are not shown in this image. The gallbladder wall is thick, but notice that there is focal disruption of the gallbladder wall mucosa with a high frequency linear transducer. In this image, you can see this area that looked irregular in the gallbladder wall. Now we can better visualize this focal ulceration within the gallbladder wall.

Another finding that historically has been reported to be associated with gallbladder wall necrosis include wall striations and that is linear hypo and hyper echogenic layers within the gallbladder wall. We now know from more recent studies that the wall striations is not a predictive finding of gangrenous cholecystitis in fact, we can see it in many conditions, including acute cholecystitis and other benign conditions related to fluid overload, congestive heart failure, hepatitis and pancreatitis. Other systemic causes resulting in gallbladder wall thickening illustrated.

On my left is a patient with acute on chronic inflammation and edema with mural striations in the gallbladder wall and on the right, a patient with acute on chronic cholecystitis with the same finding.

Emphysematous Cholecystitis

Emphysematous cholecystitis. This occurs in elderly men and diabetics path on pathology. We see thrombosis or occlusion of the cystic artery, which results in ischemic necrosis of the gallbladder. Up to 75% of patients with emphysematous cholecystitis have gangrenous changes in their gallbladder wall.

There is often no associated gallstones in patients with emphysematous cholecystitis and the gas in emphysematous cholecystitis results from infection with gas forming organisms perforation is five times more likely than with gallstone cholecystitis.

On ultrasound, we see very bright reflectors from the non-dependent portion of the gallbladder wall with dirty posterior acoustic shadowing and ring down artifact. If a ring down artifact is seen, it's a very reliable sign of gas. Within the wall illustrated is a patient with emphysematous cholecystitis.

If we look within the gallbladder lumen, we can see punctate echogenic foci in indicating gas within the gallbladder lumen. In addition, this patient also has gas within the gallbladder wall. We can see that the gallbladder wall is abnormal and their sludge within the gallbladder wall.

One thing that can be done when scanning the patient is to change position. If the patient changes position, gas tends to rise toward the non-dependent portion of the gallbladder wall. The other thing that can be done if you see punctate echogenic foci within the gallbladder lumen is to gently compress the gallbladder and the movement of the air bubbles can help with the diagnosis.

Remember that gas in the gallbladder lumen is not solely related to emphysematous cholecystitis. We can see gas in patients who've had prior sphincter, biliary enteric anastomosis or fistula illustrated.

Above and below are different patients above patients with ERCP, whose post ERCP presenting with abdominal pain and we can see that there are stones within the gallbladder. But in addition, we see bright internal reflectors with dirty posterior acoustic shadowing corresponding to air within the gallbladder lumen.

The patient below is a patient with pancreatic cancer whose status post biliary stent placement and we can see gas within the gallbladder lumen with dirty posterior acoustic shadowing. The patient below has more gas than the patient above, and a large amount of gas can be more difficult to appreciate. The absence of a normal gallbladder can be a cue when this occurs.

Mural changes that occur with emphysematous cholecystitis include hyper echoic gallbladder wall with dirty posterior acoustic shadowing and ring down artifact. In this patient, the gallbladder is distended with stones and sludge. The wall is thickened and you can see that there are focal hyper echoic area within the gallbladder wall with posterior acoustic shadowing indicating air within the gallbladder wall.

I show you the following patients with emphysematous cholecystitis to illustrate a spectrum of appearances. The patient above, you can see that there is just a linear, very bright gallbladder wall with dirty posterior acoustic shadowing corresponding to the air that's demonstrated on the CT examination and the patient below we can see punctate echogenic foci within the wall, a bit of a comet tail artifact, and this also corresponds to air within the gallbladder wall.

Be mindful that pitfalls of bright gallbladder wall include the wall echo shadow complex. The wall echo shadow complex represents a gallbladder filled with stones. With the wall echo shadow complex, we see three arc shaped lines followed by a shadow. The first line is an echogenic line representing the pericholecystic fat and interface between the gallbladder and the liver. The second line, the hypoechoic gallbladder wall versus bile in the gallbladder lumen depending on which literature you read. The third echogenic line is the echogenic stones and then shadowing from the echogenic stones.

In a porcelain gallbladder, the wall is calcified and we typically see a curvilinear semilunar line with dirty posterior acoustic shadowing with emphysematous cholecystitis, as we've described, you can see bright reflectors within the gallbladder wall with dirty posterior acoustic shadowing.

It's important to keep in mind that sometimes air within a gas filled bowel can be a mimic of a bright wall. In this patient we see that the gallbladder is decompressed and the bright echogenic focus with dirty posterior acoustic shadowing represents air within the stomach. This is easy to distinguish with real time imaging as we will see peristalsis within the bowel.

Hemorrhagic Cholecystitis

Hemorrhagic cholecystitis, it's a rare cause of abdominal pain. The etiology includes trauma, malignancy, bleeding, renal failure, cirrhosis, and patients on anticoagulation. The symptoms are quite similar to acute cholecystitis and may or may not include hemobilia as blood drains from the gallbladder into the GI tract.

On ultrasound, we see highly echogenic material within the gallbladder lumen. The easiest way to explain this is that it looks like solid appearing heterogeneous material that fills the gallbladder lumen versus sludge in the gallbladder lumen, which often layers and can be homogeneous. In addition, we can see layered echogenic material in the dependent portion of the gallbladder or linear strands of clot within the gallbladder lumen.

So if you remember, this is the patient who presented with right upper quadrant pain and had an ultrasound with this linear echogenic line paralleling the gallbladder wall suspicious for gangrenous cholecystitis. The patient had a HIDA scan, which was negative and then presented several days later with continued abdominal pain. A repeat ultrasound was performed and on the follow-up examination, the gallbladder is distended. There is echogenic material within the gallbladder lumen, which is heterogeneous and has an apparent solid appearance. There was no internal flow on colored doppler and the appearance is consistent with hemorrhage within the gallbladder lumen at surgical pathology. This patient did have a hemorrhagic cholecystitis with gangrenous changes.

The differential for this appear include tumor sludge, echogenic pus, or a solid mass. A mass can be distinguished from sludge or echogenic pus with the use of color doppler images.

This is a different patient who presented with a perforated hemorrhagic cholecystitis. Again, we can see that there is the gallbladder lumen is distended with apparent solid appearing material that is heterogeneous. There was no internal flow in color doppler, but as we scroll through the gallbladder, you can see that there's a focal disruption of the gallbladder wall with extrusion of the contents into the pericholecystic space. This was a perforated hemorrhagic cholecystitis.

A CT done after the ultrasound illustrated similar findings with the gallbladder lumen, the focal perforation with extrusion of material. This was a the liver and there was a high attenuation ascites within the abdominal cavity.

The interesting thing to keep in mind is that with patients with gangrenous cholecystitis or a perforated cholecystitis often do not have a positive sonographic Murphy sign. And so don't be alarmed if you see this patient you're scanning and they're completely comfortable despite the perforated gallbladder when perforation occurs.

We can sometimes see fluid in the pericholecystic space indicating an abscess. We can see increased echogenicity of the adjacent fat from edema and inflammation within the adjacent tissue or we can directly see gallstones extending into the pericholecystic space with associated edema within the adjacent tissue.

Acalculous Cholecystitis

Switching gears, acalculous cholecystitis, it occurs in two to 15% of patients with acute cholecystitis. The etiology include ischemia, gallbladder wall infection, chemical toxicity to the gallbladder wall or cystic duct obstruction. It occurs in very sick patients, patients who've had major surgery, extensive burns, major trauma or patients who are on TPN.

Another population that acalculous cholecystitis has been demonstrated is in healthy, older males with a high incidence of atherosclerotic disease.

On ultrasound, we can see gallbladder wall thickening, lumen distension, pericholecystic fluid or sludge. The problem with these findings is that most critically ill patients have many potential causes of the sonographic findings.

This is a great study. Looking at 44 patients in the ICU without gallstones, patients were scanned twice a week and the gallbladder was examined for the recognized sonographic features of acalculous cholecystitis and the findings were correlated to the clinical and laboratory parameters. 84% of patients had at least one sonographic abnormality. 57% of ICU patients had three sonographic abnormalities and 14% had four or five sonographic abnormalities.

The conclusion was that ultrasound is of little value in diagnosing acalculous cholecystitis on ICU patients.

It's important to note that sonographic evaluation for acalculous cholecystitis should be requested in patients with a strong clinical concern and it must correlate the ultrasound findings with the clinical history. If the sonographic findings are non-specific for acalculous cholecystitis, then we should consider morphine cholescintigraphy as its sensitivity is up to 90% versus CT at 67 or ultrasound at 29.

This is a 57-year-old female status post bilateral lung transplantation with positive Murphy sign and rising liver function tests. There was a strong clinical concern for acalculous cholecystitis and an ultrasound was requested on ultrasound. The gallbladder was distended, the wall was minimally thickened and there was sludge within the gallbladder wall. The patient subsequently had a HIDA scan, which was negative. Then the patient presented 10 days later with continued pain. On the follow-up examination, there was increased distension of the gallbladder increased wall thickening and sludge within the gallbladder. The sonographic findings along with the clinical history was concerning for acalculous cholecystitis and this patient was managed with cholecystostomy tube.

Xanthogranulomatous Cholecystitis

Xanthogranulomatous cholecystitis is a rare inflammatory disease that may be difficult to differentiate from a malignancy. It occurs in women greater than men and it presents at 60 to 80 years. The symptoms include right upper quadrant pain, a positive sonographic Murphy sign and leukocytosis On pathology. We see collections of lipid laden macrophages with grayish yellow nodules or streaks in the gallbladder wall.

The sonographic features of xanthogranulomatous cholecystitis include gallbladder wall thickening, which can be focal or diffuse intramural hypoechoic nodules or bands. Patients may or may not have loss of the intervening fat plane between the liver with focal hypoechogenicity of the hepatic parenchyma gallstones are often present.

This is a 60-year-old woman with history of gallstones for 30 years who presented with intermittent right upper quadrant pain that has been worsening over the past seven months. On ultrasound, these are the top row longitudinal images of the gallbladder and beneath transverse images of the gallbladder, you can see that the gallbladder is filled with stones. The wall is thickened, but in the area near the gallbladder fundus, the wall becomes more focal thickened and there is soft tissue material that extends between the gallbladder wall and the liver. The interface between the gallbladder wall and the liver is difficult to discern and this appearance raise concern for a gallbladder cancer.

On CT there are stones within the gallbladder lumen and there is loss of the normal fat plane between the gallbladder wall in the fundus and the liver. This patient went for surgery and the pathology, this was xanthogranulomatous cholecystitis gallbladder cancer.

Gallbladder Cancer

Gallbladder cancer. It's the fifth most common GI malignancy. The majority are associated with gallstones. It occurs in women greater than men. The prognosis is poor and 80% of patients will have direct tumor invasion of the liver or portal node involvement. At the time of diagnosis on ultrasound, we see a mass centered in the gallbladder fossa that completely or partially obliterates the lumen and there may or may not be gallstones within the mass. This is the most common presentation of gallbladder cancer.

In 15 to 30% of cases, we can see focal or diffuse gallbladder wall thickening, and if this occurs, the gallbladder wall thickening is typically irregular, asymmetric or eccentric. We can also see a polypoid intraluminal mass, but that's usually greater than a centimeter. But this is the least common presentation for gallbladder cancer.

This is a patient who presented with right upper quadrant pain and abnormal liver enzymes. On ultrasound, you can see that there is a mass centered in the gallbladder lumen that extends into the liver parenchyma. There are stones within the gallbladder and note that it is very difficult to discern where the gallbladder starts and where the mass ends because of the direct invasion of The Tumor.

The differential for gallbladder cancer include tumor sludge, perforated cholecystitis, fundal adenomyomatosis metastasis polyps and xanthogranulomatous cholecystitis.

This is a patient who was sent to us after a CT scan that was suspicious for gallbladder cancer and an ultrasound. There was a focal area of decreased echogenicity within the gallbladder wall with fluid on the extending into the liver parenchyma. There's soft tissue density within the hepatic parenchyma with increase flow and color doppler. The sonographic features favored a perforated cholecystitis and less likely a gallbladder cancer, and on subsequent biopsies ultimately demonstrated that this was a perforated cholecystitis.

This is the patient I showed earlier with xanthogranulomatous cholecystitis with more increased focal gallbladder wall thickening involving the fundus with extension toward the liver. Again, a finding that makes distinction from cancer difficult.

This patient had newly diagnosed lung cancer and on a PET CT examination there was abnormal FDG uptake within the thyroid and the gallbladder lumen. The thyroid was biopsied and it was metastatic lung cancer. And on ultrasound we see a soft tissue density within the gallbladder lumen. To distinguish this from sludge, we used color doppler and we can see that this is indeed a soft tissue mass and not sludge.

One thing to keep in mind and the with gallbladder cancer, it starts within the gallbladder wall and oftentimes by the when we see it on ultrasound, there is extension into the liver parenchyma and there is loss of the normal fat plane between the gallbladder lumen and the liver. With gallbladder cancer, it's very difficult to distinguish where does the gallbladder end and the liver begin. In this patient, although there was a soft tissue mass within the gallbladder lumen, you can clearly see that the wall is very well preserved and in light of the history of squamous cell carcinoma with known mets to the thyroid gland, this was presumed gallbladder metastases.

Gallbladder polyps is another differential consideration for a cancer, but typically polyps less than one centimeter are unlikely to represent cancer. This patient had multiple polyps all of which I'm not showing. There was a linear stalk within the gallbladder because of the size and the frond like appearance. This patient went to surgery and at surgical pathology, this was cholesterol polyp.

Cholesterol effective sludge is another differential consideration for gallbladder cancer and the cholesterol effective sludge can be distinguished readily from a mass by mobility. So just roll the patient and if this moves, then you know that it's sludge. If you're unable to roll the patient, you can place color doppler and if there's no internal flow on Doppler, then you have your answer.

Finally, this is a patient who actually presented to ultrasound because of concern for a gallbladder mass near the fundus. On this CT examination on ultrasound, we can see that there is focal thickening of the gallbladder wall near the fundus, but if you look carefully, you can see that there are little punctate cystic spaces within this thickened gallbladder wall indicating small Rokitansky Aschoff sinuses. In addition, there was comet tailing and a twinkle artifact within the gallbladder wall, and this is a finding of gallbladder adenomyomatosis.

Porcelain Gallbladder

Porcelain gallbladder is a rare entity that occurs in less than 1% of cholecystectomy specimens. Women are affected more than men and it occurs in the six decade of life. It is associated with chronic gallbladder inflammation and the majority of cases have gallstones.

Historically, porcelain gallbladder has been associated with an increased risk of gallbladder cancer with estimates ranging between 12 and 61%. However, the rate of cancer is significantly lower than previous estimates. This great study by Stephen showed that the incidence of gallbladder cancer in patients with porcelain gallbladder depends on the pattern of gallbladder wall calcification. In patients who have focal mucosal calcification, the risk of cancer was 7%, and in patients with diffuse intramural calcification, there was no risk of cancer.

Three distinct sonographic patterns have been described with in porcelain gallbladder. It includes a hyperechoic semilunar structure with complete posterior acoustic shadowing, a biconvex curvilinear echogenic structure with variable posterior acoustic shadowing and irregular clumps of echoes with posterior acoustic shadowing.

Illustrated are two different patients with porcelain gallbladder. On my left, a thickly calcified gallbladder wall with hyperechoic semilunar line with dependent posterior acoustic shadowing. And on my right, the biconvex pattern echogenic line with variable posterior acoustic shadowing.

Summary

In summary, in evaluating patients with complicated cholecystitis, one approach can be to look at the luminal changes including sloughed mucosa, hemorrhage, or abnormal gas mural changes, which can include focal ulcerations disruptions, abnormal gas loss of ano reflexivity or focal bulge or pericholecystic changes including pericholecystic fluid abscess formation, or increased echogenic fat.

Remember that acalculous cholecystitis ultrasound must be interpreted with the clinical context. Gallbladder cancer typically presents late as a mass obliterating the gallbladder lumen and engulfing stones xanthogranulomatous cholecystitis may be difficult to differentiate from malignancy, and the risk of gallbladder cancer in porcelain gallbladder is significantly lower than previous estimates with focal mucosal calcification demonstrating an increased risk of up to 7%.

Thank you for your time and attention.