Focal Vs Diffuse Gall Bladder Wall Thickening

Objectives

• Normal GB wall Appearance• Causes Of focal GB wall thickening• Causes of diffuse GB wall thickening• Appearances of different conditions• Differentiating points• Pitfalls of GB wall thickening

Gall Bladder

• Normal wall thickness < 3mm• The normal gallbladder wall appears

as a pencil-thin echogenic line at sonography.

• The thickness of the gallbladder wall depends on the degree of gallbladder distention and pseudothickening can occur in the postprandial state.

LEFT: US of a normal gallbladder after an overnight fast shows the wall as a pencil-thin echogenic line (arrow).RIGHT: US in the postprandial state shows pseudothickening of the gallbladder

The normal gallbladder wall is usually perceptible at CT as a thin rim of soft-tissue density that enhances after contrast injection.

Thickened gallbladder wall

• Thickening of the gallbladder wall is a relatively frequent finding at diagnostic imaging studies.

• A thickened gallbladder wall measures more than 3 mm, typically has a layered appearance at sonography , and at CT frequently contains a hypodense layer of subserosal oedema that mimics pericholecystic fluid.

LEFT: US in a 59-year-old woman with acute cholecystitis shows the layered appearance of a thickened gallbladder wall, with a hypoechoic region between echogenic linesRIGHT: At contrast-enhanced CT the thick-walled gallbladder contains a hypodense outer layer (arrow) due to subserosal oedema

Focal Wall Thickening

• Polyps• Adenomyomatosis• Carcinoma• Xanthogranulomatous cholecystitis• Metastasis• Chronic cholecystitis• Tumefactive sludge / Sludge balls

Polyps/ Cholesterolosis

• A condition in which triglycerides, cholesterol esters and cholesterol precursors are deposited in lamina propria of GB.

• Cause is unknown• Not related to serum lipid level,

atherosclerosis, diabetes, cholesterol stones, or hyperconcentration of cholesterol in bile.

• Most cases do not produce any detectable change in appearance.

• Sometimes referred to as “Strawberry gallbladder”

• Minority of cases are of polypoid variety• Cholesterol polyps are “enlarged

papillary fronds filled with lipid laden macrophages”

• Attached to the wall by a stalk• “Ball on the wall”• 5mm or less, rarely get bigger than

10mm

• Do not acoustic shadowing• Do not exhibit postural movement• Other less common types of polyps

are adenoma papilloma leiomyoma lipoma neuroma

• Polyps < 5mm – no further evaluation 5-10mm – monitoring > 10mm – should be removed• As the polyp enlarges – risk of

malignancy increases

Large Fibrous Polyps of the Gallbladder Simulating Gallbladder Carcinoma

GB Polyp fixed to the ventral wall of the GB

Diffuse Wall Thickness

• CAUSES• Biliary Causes 1.Cholecystitis 2.Adenomyomatosis 3.Cancer 4.AIDS cholangiopathy 5.Sclerosing cholangitis

• NON BILIARY CAUSES 1.Hepatitis 2.Pancreatitis 3.Heart Failure 4.Hypoproteinemia 5.Cirrhosis 6.Portal hypertension 7.Lymphatic obstruction

Cholecystitis

• Acute• Chronic• Acalculous• Xanthogranulomatous

Acute cholecystitis

• Fourth most common cause of hospital admissions for patients presenting with an acute abdomen

• It is the prime diagnostic concern when a thick-walled gallbladder is found at imaging.

• This feature, however, is not pathognomonic and additional imaging signs should be present to support the diagnosis of acute calculous cholecystitis.

Signs of Acute cholecystitis

• Thickened gall bladder wall• Obstructing gallstone• Hydropical dilatation of the gallbladder,• A positive sonographic Murphy's sign

( i.e., pain elicited by pressure over the sonographically located gallbladder),

• Pericholecystic fat inflammation or fluid • Hyperemia of the gallbladder wall at

power Doppler

Acute calculous cholecystitis. Transverse sonogram at the spot of maximum tenderness shows a non-compressible hydropically distended thick-walled gallbladder (arrowheads), with an intraluminal stone and sludge or debris. Contrast-enhanced CT depicts extensive fat inflammation (arrowheads) surrounding the gallbladder (arrow).

Chronic cholecystitis

• Chronic cholecystitis is a term used clinically to refer to symptomatic gallbladder stones that cause transient obstruction, leading to a low-grade inflammation with fibrosis .

• Correlation of the imaging finding of a stone-containing slightly thick-walled gallbladder with the clinical history is critical.

Chronic cholecystitis. Longitudinal sonogram of the gallbladder shows slight wall thickening (arrow) and an intraluminal non-obstructing stone

Acalculous cholecystitis

• Mainly occurs in critically ill patients, (Major surgery, Major trauma,extensive

burns)• Due to Increased bile viscosity from fasting and Medication that causes cholestasis. • The imaging features are those of acute

cholecystitis, except for the absence of stones whereas gallbladder sludge is usually present.

Acalculous cholecystitis

PITFALL• Because in critically ill patients

gallbladder abnormalities are frequently found secondary to systemic disease , acalculous cholecystitis can be difficult to diagnose .

• In these patients a percutaneous cholecystostomy can be both diagnostic and therapeutic.

74-year-old man with acute acalculous cholecystitis.LEFT: US at the spot of maximum tenderness shows mural thickening of the gallbladder (arrow) that is completely filled with sludge (asterix) without any stones.RIGHT: Power-Doppler sonography shows hypervascularity of the gallbladder wall (arrowhead), as a supporting sign of inflammation.

Xanthogranulomatous cholecystitis

• Unusual variant of chronic cholecystitis,

• Characterized by a Destructive inflammatory process with varying proportions of fibrous tissue, inflammatory cells and lipid laden macrophages

• Gall stones +/-• Locally invasive

• Imaging studies show marked gallbladder wall thickening, often containing intramural nodules that are hypoechoic at sonography and hypoattenuating at CT, representing abscesses or foci of xanthogranulomatous inflammation.

• These features overlap with those of gallbladder carcinoma, making preoperative distinction between these entities often impossible.

Xanthogranulomatous cholecystitis. LEFT: US shows marked wall thickening with intramural hypoechoic nodules (arrowheads), and an intraluminal stone (arrow).RIGHT: Contrast-enhanced CT shows a deformed and thickened gallbladder wall containing hypoattenuating nodules

Contrast-enhanced CT shows a deformed and thickened gallbladder wall containing hypoattenuating nodules . These represent abscesses or foci of inflammation. The lumen contains several stones (arrow).

Adenomyomatosis

• Benign condition that requires no specific treatment,

• Incidental finding in upto 9% of cholecystectomy specimens

Characterized by • 1. Epithelial proliferation, • 2. Muscular hypertrophia and • 3. Intramural diverticula (Rokitansky-

Aschoff sinuses), which may segmentally or diffusely involve the gallbladder.

• The sonographic finding of cholesterol crystals, shown as 'comet-tail' reverberation artifacts, within a thickened wall of the gallbladder strongly suggests this diagnosis.

• Air may produce a similar artifact, however, patients with emphysematous cholecystitis are usually ill in contrast to those with adenomyomatosis.

• MR imaging may be able to differentiate adenomyomatosis from gallbladder carcinoma by depicting Rokitansky-Aschoff sinuses.

Four types of gallbladder adenomyomatosis

• A. Annular type. • B. Segmental type, which describes an

annular or segmental wall thickening causing stricture that divides the gallbladder lumen into separate interconnected compartments.

• C. Fundal type,(adenomyoma) a focal elevated lesion with a central dimple located at the fundus of the gallbladder.

• D .Diffuse type, a thickened wall involving the entire gallbladder.

• Exclusion of gallbladder cancer may be most problematic in segmental and focal cases. Focal adenomyomatosis may appear as a discrete mass, known as an adenomyoma.

Diffuse adenomyomatosis of gall bladder. These gall bladder ultrasound images show multiple echogenic foci within the GB wall with V-shaped comet-tail .

Gallbladder Adenomyomatosis: Axial CT of the abdomen with oral and IV contrast shows focal thickening of the gallbladder wall (arrows)

Oral cholecystogram and MRCP

• Historically oral cholecystograms were performed, however due to low sensitivity and a high rate of contrast allergies it has now largely been replaced by MRCP which does not rely on contrast opacification of the lumen of the gallbladder.

• MRCP would be also to detect :• mural thickening• focal sessile mass• pearl necklace sign (fluid filled intramural

diverticula)• hourglass configuration in annular types

Rokitansky-Aschoff sinuses shown on the after fatty meal film at cholecystography Stricture is also present.

Fundal nodule of adenomyomatosis before and aftergallbladder contraction.

MRI

• The pearl necklace sign alludes to the characteristically curvilinear arrangement of multiple rounded hyperintense intraluminal cavities visualized at T2-weighted MR imaging and MR cholangiopancreatography of adenomyomatosis.

pearl necklace sign

• It represents the contrast / fluid filled intramural mucosal diverticula (Rokitansky-Aschoff sinuses) which line up reminiscent of pearls on a necklace.

• highly specific (92%)• frequently not seen,• only present in ~ 70% of cases

coronal T2

Gallbladder carcinoma

• Fifth most common malignancy of the GIT• found incidentally in 1% to 3% of cholecystectomy

specimens. • It is often detected at a late stage of the disease,

due to lack of early or specific symptoms. • Gallbladder carcinoma has various imaging

appearances, ranging from a - polypoid intra-luminal lesion to -an infiltrating mass replacing the

gallbladder, -diffuse mural thickening.

Associated findings

• -- invasion of adjacent structures, • --secondary bile duct dilatation, and • --liver or nodal metastases may help in differentiating a carcinoma from

acute or xanthogranulomatous cholecystitis .• In absence of these associated

findings, it may not be possible to differentiate a carcinoma from xanthogranulomatous cholecystitis.

Pathology

• 90% are adenocarcinoma , • 5% are squamous carcinomas and• 5% is anaplastic carcinomas.• They appear as gallbladder wall

thickening and induration. • Most common sites are at the

fundus and neck of the gallbladder• Pocelain GB and sclerosing

cholangitis are predisposing factors

SPREADS 80% are detected after direct invasion or portal node involvement.

• Local direct invasion into the hepatic bed,

• Lymphatic spread into the cystic nodes, hiatal nodes and then to the superior and posterior pancreaticoduodenal nodes and the periaortic nodes.

• Blood borne spreads via the portal vein to the liver

• 5 yr survival is < 20%

Investigations

• Abdominal ultrasound scan : may shows gallbladder wall thickening or a mass filling the gallbladder , which would be suggestive of malignancy.

• CT or MRI scan : show a mass in the region of gallbladder.

• Arteriographic CT portogram ; Where contrast is injected into the superior mesenteric artery , allows accurate measurements of the extent of the disease and is resectability.

Gall bladder carcinoma with portal vein and biliary tree infiltration

Abnormal gallbladder with stones and sludge and a thickened irregular wall. Liver metastases and tumor thrombus in the left portal vein.

Portal Venous phase--- GB Ca

This sagittal sonogram image demonstrates heterogeneous thickening of the gallbladder wall (arrows), found to be primary papillary adenocarcinoma

Primary Sclerosing Cholangitis

• Etiology –unknown• Inflammatory process affecting

intra and extra hepatic ducts• Presentation and course is highly

variable• May present in infancy or old age• C/C --- cholestasis• Predisposition ---to bile duct cancer

• Multifocal stricture of bile duct• 86% will have both intra and extra

hepatic involvement

Characteristic intrahepatic strictures of sclerosing cholangitis.

Characteristic stricturing of sclerosing cholangitis involvingthe intra- and extrahepatic biliary system.

AIDS cholangiopathy

• Obliterative cholangiopathy due to oppurtunistic infection of the bile duct by

-CMV -Pnemocystis carinii -Cryptosporidium• Presentation is similar to PSC• C/C abd. Pain and cholangitis• Tx .. Endoscopic sphincterotomy

• NON BILIARY CAUSES 1.Hepatitis 2.Pancreatitis 3.Heart Failure 4.Hypoproteinemia 5.Cirrhosis 6.Portal hypertension 7.Lymphatic obstruction

Edematous thickening of the gallbladder wall in a patient with cardiac failure and ascites.

Edematous thickened gallbladder wall in a patient with cardiac failure

Edematous thickened gallbladder wall in a patient with hepatitis

Hepatitis with a thickened gallbladder wall

Gallbladder wall thickening in a patient with a sepsis and hepatosplenomegaly

The image above was taken in a patient with cirrhosis, chronic ascites, and no acute complaints of upper abdominal pain.

How to differentiate b/w cholecystitis and non biliary

causes

??

How to differentiate b/w cholecystitis and non biliary

causes

• Clinical correlation• Presence and absence of

sonographic Murphy’s sign• Associated signs e.g. Pulsatile portal venous flow in

heart failure Portal HTN & nodular liver in

Cirrhosis

Conclusion

• GB wall thickness can be --Focal --Generalized• Both biliary and non-biliary causes

can result in increase in wall thickness

• Clinical correlation is important

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