IMAGING IN BILIARY SYSTEM AND Gb PATHOLOGIES

BY DR PAUL JOY

MODERATOR: DR GURURAJ SHARMA

ROLE OF IMAGING IN OBSTRUCTIVE JAUNDICE

OBSTRUCTIVE JAUNDICE•Aetiology

▫Benign disease (76%) Post operative stricture Calculi in biliary tree Chronic pancreatitis Sclerosing cholangitis Recurrent pyogenic

cholangitis Hepato-biliary ascariasis Papillary stenosis Liver cysts

•Aetiology▫Malignancy (24%)

Pancreatic carcinoma Periampullary Ca Cholangiocarcinoma Metastatic disease

Site of obstruction Causes Extrahepatic

Distal CBD Choledocholithiasis (90%) Peri- ampullary tumours Strictures Suprapancreatic CBD Cholangiocarcinoma (5%) Metastatic lymph nodes

At Porta Cholangiocarcinoma (5%) Strictures

Hepatic tumours GB carcinoma Lymph nodes

Intrahepatic

Intrahepatic tumours Caroli’s disease Cholangitis Haemobilia

Role of Imaging• Identify dilatation of intra and extra-hepatic biliary

channels

• Identify level of obstruction

• Identify possible cause of obstruction

• If obstruction appears to be malignant a)Is there evidence of non resecetablility ? b)In those with malignant hilar obstruction unsuitable

for surgery , what approach should be taken for palliative stenting ?

MODALITIES AVAILABLE

Plain Radiographs Oral Cholecystography Intravenous Cholangiogram Ultrasonography Computed Tomography MRI and MRCP Radionuclide Imaging Percutaneous Transhepatic Cholangiogram Endoscopic Retrograde Cholangiopancreatography

PLAIN RADIOGRAPHS Detect calcified gall stones only (20-30%) gall stones could be mixture of Cholesterol , Pigment ,and calcium bile

salts The densest stones is pure Calcium bicarbonate stone called as mulberry stone.

If radiopaque , it may show stellate faced appearance with gas containing fissures

( Mercedez Benz sign) Limy bile : Bile with high calcium content . A layering effect is seen on a horizontal

ray projection Mural calcification : Galll bladder wall undergoing calcification as a sequelae to Choninc

inflammatory change , producing porcelain gall bladder Mural Gas : Emphysematous Cholecystitis Gas in biliary tree: ▫ Central distribution of gas and anterior distribution in left and anterior

sectoral right duct system .▫ Portal venous gas : Peripheral distribution

ORAL CHOLECYSTOGRAPHY• For an OCG, the patient takes iodine-containing tablets (telepaque-

iopanoic acid) by mouth for one night or two nights in a row. • The iodine is absorbed from the intestine into the bloodstream,

removed from the blood by the liver, and excreted by the liver ( Enterohepatic recirculation ) and into the bile.

• The iodine, together with the bile, is highly concentrated in the gall bladder.

• The bile ducts themselves cannot be seen on the x-ray in an OCG because the iodine is not concentrated in the ducts. Therefore, any gallstones lodged in the ducts will go undetected on OCG.

• Contraindications:▫ Pregnancy▫ Acute cholecystitis▫ Acute renal failure▫ Allergy to contrast medium

ORAL CHOLECYSTOGRAPHY

Opacified Gall Bladder

INTRAVENOUS CHOLANGIOGRAPHY• An Xray examination of the bile ducts.

• Contrast medium (cholograffin-iopamide meglutimine) injected into a vein is excreted through the liver and the bile ducts are opacified.

• The procedure can be used to locate gallstones within these bile ducts.

• IVC also can be used to identify other causes of obstruction to the flow of bile, for example, narrowings (strictures) of the bile ducts and cancers that may impair the normal flow of bile.

Radionuclide Imaging• This scan is also known as a HIDA (tc 99m hepatobiliary iminodiacetic acid) scan.• Its role is to demonstrate the flow of bile in the body.

• Indications-• Gallbladder inflammation (cholecystitis)• Bile duct obstruction• Congenital abnormalities in the bile ducts, such as biliary

atresia• Postoperative complications, such as bile leaks and fistulas• Assessment of liver transplant

• A small amount of radioactive tracer, known as Tc-99m is given intravenously.

• Following this, when the gall bladder has filled sufficiently an intravenous infusion of cholecystokinin is commenced and run slow through the cannula over an additional 60 minutes. This will cause the gall bladder to contract.

• The difference in volume of the gallbladder before and after the cholecystokinin can be determined and expressed as what is known as the ejection fraction.

• Normally an ejection fraction greater than 35-40% indicates that the gall bladder is contracting normally.

• Sometimes a gall bladder may not contract well when it has been subject to chronic inflammation.

• The dynamics of the bile ducts can also be measured by means of computer analysis to indicate whether the sphincter of Oddi is functioning normally, or if other problems exist further upstream.

PERCUTANEOUS TRANS-HEPATIC CHOLANGIOGRAPHY• Percutaneous transhepatic cholangiography (PTC) is a radiographic

technique employed in visualisation of the biliary tract, and can be used as the first step in a number of percutaneous biliary interventions(e.g.  percutaneous transhepatic biliary stent placement)

• Indications• Failed ERCP / ERCP not feasible (e.g. patients with gastrojejunostomy)• Biliary system delineation in presence of intra and extrahepatic biliary

calculi• To identify obstructive cause of jaundice; and differentiate from

medically treatable cause• Anatomic evaluation of complications of ERCP• Delineating bile leaks

• Contraindications• bleeding diathesis• gross ascites

ULTRASONOGRAPHY•Dilated IHBR seen as linear branching

anechoic structures parallel to the portal venous radicles

• IHBR more than 40 % of diameter of accompanying portal vein or more than 2 mm in diameter is considered dilated

•Normal CBD ranges from 5to 8 mm. Wider in elderly and post cholecystectomy(upto 12) patients

MAGNETIC RESONANCE CHOLANGIO-PANCREATOGRAPHY (MRCP)

Normal anatomy

Dilated CBD on MRI

Dilated IHBR and CBD on MRCP

ERCP• Endoscopic retrograde cholangiopancreatography (ERCP) is

a technique that combines the use of endoscopy and fluoroscopy to diagnose and treat certain problems of the biliary or pancreatic ductal systems.

• Through the endoscope, the physician can see the inside of the stomach  and duodenum , and inject radiographic contrast into the ducts in the biliary tree and pancreas so they can be seen on X-rays.

• ERCP is used primarily to diagnose and treat conditions of the bile ducts and main pancreatic duct,

 including gallstones, inflammatory strictures (scars), leaks (from trauma and surgery), and cancer. ERCP can be performed for diagnostic and therapeutic reasons

Causes of Obstructive Jaundice• Congenital - Choledochal cyst - Pancreas Divisum - Annular pancreas• Benign

▫ Biliary calculi▫ Hepatolithiais ▫ Benign Biliary strictures : a)Post op strictures b) Primary Sclerosing

Cholangitis c) Mirizzi s Syndrome d) Pancreatitis e) IG4 related sclerosing dis e) HIV Cholangiopathy f) Acute bacterial Cholangitis g) Recurrent pyogenic cholangitis ▫ Parasitic infections ▫ Biliary leak and bile duct injury ▫ Biliary cystic disease

• Malignant▫ Gall bladder carcinoma ▫ Cholangio carcinoma ▫ Carcinoma head of Pancreas

Choledochal cysts•Choledochal cysts represent congenital

disproportionate cystic dilatations of the biliary tree.

•Often diagnosed in children . Mostly asymptomatic , but can present with non specific abdominal pain , right upper quad mass and jaundice.

•Diagnosis relies on the exclusion of other conditions as a cause of biliary duct dilatation: (i.e. tumour, gallstone or inflammation as the cause).

• USG :▫Cystic or fusiform dilatation of CBD

• MRCP :▫Modality of choice▫Delineates type & extent of cyst, Pancreatico-biliary

junction & associated complication if any▫Depicts cystic or fusiform dilatation of part or whole

of CBD

•  Todani et al has classified into 5 main types

• I: most common (80-90%) (this type can present in utero)• Sacccular /fusiform dilatation of all or part of extrahepatic bile duct with normal intrahepatic ducts

▫ Ia: dilatation of extrahepatic bile duct (entire)▫ Ib: dilatation of extrahepatic bile duct (focal segment)▫ Ic: dilatation of the common bile duct portion of extrahepatic bile duct

• II:  true diverticulum from extra hepatic bile duct

• III: dilatation of extra-hepatic bile duct within duodenal wall (choledochocoele) Ectasia of intramural CBD .

• IV: Multiple intra and extrahepatic biliary cyst (next most common )▫ IVa: cysts involving both intra and extrahepatic ducts▫ IVb: multiple dilatations/cysts of extra hepatic ducts only

• V: mult iple dilatations/cysts of intra hepatic ducts only (Caroli disease)

CHOLEDOCHAL CYST

CAROLI S DISEASE • Typical cholangiographic features are those of an

irregular intrahepatic duct system , which may be total , lobar or segmental in distribution

• Stone formation and cholangitis develops • Its associated with congenital hepatic fibrosis and

cystic disease of kidneys ie autosomal recessive Fibropolycystic disease

• ARFPD: Chronic renal failure/Renal duct ectasia Minor bile duct dilatation Portal hypertension severe cirrhosis

Biliary atresia•Biliary atresia (BA) is a congenital biliary

disorder, which is characterised by an absence or severe deficiency of the extra-hepatic biliary tree.

•Most common causes of neonatal cholestasis, often causing cirrhosis immediately and leading to death and accounts for over half of children who undergo liver transplantation. 

• It is thought to result from idiopathic destructive inflammatory process which leads to fibrotic remnants at porta hepatis.

• Ultrasonography: - Technique: fasting at least 4 hours before examination

- The gallbladder ghost triad: a gallbladder length less than 1.5cm( 1.9cm), a thin or indistinct gall bladder wall, and an irregular and lobular contour.

- The triangular cord sign( TC sign): a circumscribed, focal, triangular or tubular echogenic density more than 3 mm thick located cranial to the portal vein bifurcation.

- Central biliary cysts and choledochal cysts may be associated with biliary atresia.

Gallblader Gallbladder ghost triad

in babies with biliary atresia. A short gallbladder, an irregular or lobulated contour, and a relatively indistinct lining and wall

Hepatobiliary scintigraphyA technetium-labeled iminodiacetic

acid (IDA) analogue is typically used, include99m Tc (technetium-99m) DISIDA (di isopropyl-iminodiacetic acid) and99m Tc mebrofenin (trimethylbromo-iminodiacetic acid).

Infants with biliary atresia usually have normal hepatocyte uptake of the radiotracer if they are younger than 2 months of age.

If excretion of radiotracer into the bowel is seen, biliary atresia is virtually excluded. If radiotracer excretion is absent after 24 hours (as it is in the image below), biliary atresia is suspected.

Primary Sclerosing Cholangitis

• PSC is an idiopathic disuse , fibrosing inflammatory process of the the intrahepatic and extraheptic bile ducts . Commony seen in males (70%)

and with median age of onset of 40 years.

• Thought to be autoimmune disease and can be seen associated with Ulcerative colitis , Riedel s struma , orbital pseudotumour retroperitoneal fibrosis , mediastinal fibrosis , Sjogren s syndrome

• 15 % of cases are complicated with Cholangiocarcinoma and acute infectious cholangitis (due to biliary stasis)

Radiological features• Ultrasound• Ultrasound is able to demonstrate both the changes of cirrhosis

and irregularity of bile duct calibre. • USG diagnosis is difficult because bile duct dilatation in PSC is

minimal due to surrounding fibrotic reaction

• CT• Duct wall thickenening with marked post Con Enhancment , skip

dilatation , stenosis and mural webs can be seen.• Multiple linear discontinuous low density regions representing

dilated intra-hepatic bile duct segments 

• Rounded with lobulated contour of liver and atrophy ( lateral segments of left lobe and posterior segments of right hepatic lobe )

• Marked caudate lobe hypertrophy• The atrophied liver is of lower density than the hypertrophied

caudate lobe.

• Cholangiography / ERCP• ERCP remains the gold standard for the depiction of the biliary tree,

and also offers the ability to perform cholangioplasty if necessary.• The characteristic findings on direct imaging of the biliary tree

are 2-3,5:• multiple segmental strictures of both intra and extra hepatic bile

ducts ▫ typically short segment band like stricture ( 1-2mm)▫ intervening segments are of normal calibre or slightly dilated

(beading)• biliary dilatation: may be present in ~85% of cases 9

▫ general: ~35%▫ segmental: ~50%

• biliary diverticula ( 1 mm to 1 cm ) in extra hep bile ducts and intraluminal webs.

• Fibrous obliteration of peripheral bile ducts can result in pruned tree appearance

• PSC bile duct irregularity cn be seen as subtle brush border like appearance to shaggy or frankly nodular appearance

• distortion of the biliary tree due to associated cirrhosis

MRCP • There is good correlation between ERCP and MRCP in diagnosis of PSC• MRCP will show all the finding earlier described • Additional findings :• Duct wall thickeneing and Enhancement • Morphological changes to (Liver post cirrhosis )• Randomly distributed T1 hyperintense areas , reticular or peripheral

wedge shaped T2 hyperintense areas and large nodular lesions (>3cm) (which are isointense on T1 and hypointense on T2 ) predominantly in central part of liver. PSC results in atrophy of peripheral wedge shaped areas in the liver which appear Hypo on T1 and Hyper on T2 and shows delayed

enhancement .

CHOLANGIO CA with PSC will show : Markerd duct dilation , progressive stricture

and the prescence of intraluminal polypoidal mass 1cm or more in diameter

PSC with thickening of the wall of the bile duct (arrow)

Primary sclerosing cholangitis: MRCP and ERCP

Primary sclerosing cholangitis (PSC) with multiple intrahepatic strictures.

• MRI 3D MIP showing Primary sclerosing cholangitis (PSC) with multiple intrahepatic strictures.

Mirizzi Syndrome • Complication of long standing Cholelithiasis Charecterised by Common hepatic

duct or CBD obstruction due to extrinsic compression from an impacted gall stone in cystic duct or gall bladder neck or from associated inflammatory changes .

• Complications : Fistula formation between the gall bladder and the CHD/CBD secondary to

eroding stone .

• IMPORTANCE: Identification is crucial preoperatively since there is increased risk of extrahepatic

bile duct injury due to dense fibrosis around the hepatoduodenal ligament

• HALLMARK FEATURE : Cholelithiasis with IHBR and Dilated Common Duct till the porta hepatis beyond

which CDB is normal in calibre

Mirizzi syndrome—MRCP. Coronal thick-slab MIP image from MRCP shows a gallstone in the gb neckcausing dilatation of the gb and obstruction of the commonhepatic duct

CHOLANGIOCARCINOMA• Cholangiocarcinoma is the most common malignant tumor arising

from the epithelium of the bile ducts.

• RISK FACTORS : Primary sclerosing Cholangitis Carolis disease Choledochal cyst Familial Polyposis Congenital hepatic fibrosis Biliary enteric anastomosis History of exposure to thoradust • Peak incidence : 6th to 7th decade More common in males 95% are adenocarcinoma s of bile duct epithelium and have

abundant fibrous storma

CLASSIFICATION • ANATOMICALLY :• Intrahepatic peripheral chol –

ngioarcinoma , arises peripheral to secondary confluence .

• Hilar Cholangioarcinoma : Arises from right or left hepatic ducts or fron primary biliary confluence .

• Extrahepatic Cholangiocarcinoma

• MOPHOLOGICALLY :• Mass forming

cholangiocarcinoma

• Periductal cholangiocarcinoma

• Intraductal chollangiocarcinoma

INTRAHEPATIC CHOLANGIO CA • Late presentation with either a) large well defined mass

with lobular margins b)Purely periductal infiltrating c) Mixed with mass forming and periductal infiltrating.

• USG:• Hypoechoic , isoechoic or hyperechoic mass which may be

homogenous or heterogenous .• CT: Hypodense solitary mas with satellite nodules Post con : Thin rim/Thick band of peripheral and patchy

enhancement . The central area of tumour , which contains fibrous tissues does not enhance during early phase but shows progressive centripetal enhacement and retension on delayed images during delayed phase 4-20min ( Helps to dfferenciae from HCC )

• Vascular invasion • Focal intrahepatic biliary duct dilatation and atrophy of the segment of the liver drained by these ducts with capsular

retraction .• Since cholangiocarcinoma has no capsule their margins are

infiltrative and difficult to predict on imaging

• MRI: Irregular heteroechoic mass hypointense on T1 and Hyperintense

on T2 wt images

HILAR CHOLANGIOCARCINOMA(klatskin tumour)• Mostly periductal infiltrating type and most often arise

at the primary confluence or in the proximal common hepatic duct .

• USG:• IHBR with/without isolation of left and right sided ducts

and lobar atrophy• Defnitive mass is rarely seen on USG , so IHBR without

evidence of extrahepatic dilatation alone should raise suspicion of Hilar cholangiocarcinoma

• CT :• Tumour might appear hypodense to liver in both unenhanced and

Enhanced images , But Focally thickened bile duct wall due to infiltrating tumour may appear hyperdense to the liver in the arterial and portal venous phase .

Delayed enhancement can be seen in 8-15 min post Contrast injection.

• MRI • Iso/hypointese on T1 and Hyperintense on T2 • Lobar hepatic atrophy due to long standing biliary

obstruction/portal venous invmt and results in crowding of dilated biliary ducts and Volume loss mostly of left lobe of liver

• Biliary dilatation .• Contigous invasion of liver parenchyma and hepatoduodenal

ligament is a feature of KLASKIN TUMOUR

•Lymphnodal metastasis can be seen in Periportal and peripancreatic regions

•Complications: Retroperitoneal lymphadenopathy Proximal intestinal obstruction Peritoneal dissemination Unresectable lesions:• If they involve bilateral secondary confluence or

main portal vein or hepatic artery or bilateral vascular involvement or vascular involvement on one side and extensive bile duct involvement on the other side

CLASSIFICATION• Determine the exact location of the tumor mass

and can be used in preoperative assessment. The Bismuth-Corlette system is one classification:

• type I:  the lesion is limited to the common hepatic duct distal to the confluence of right and left ducts

• type II:  the tumor involves the confluence of right and left hepatic ducts

• type III: the tumor involves one of the hepatic ducts

• type IV: the tumor invades the right and left hepatic ducts and hence it becomes unresectable

tumor at the confluens of the left and right hepatic duct.The margins of the tumor however are imperceptible because of the infiltrative growth.

GALL BLADDER

Elliptical organ.

Location: between anatomical Rt & Lt lobe of liver. Parts:

FundusBodyInfundibulum (Hartmann’s pouch)Neck

INTERIOR OF GALL BLADDER AND BILE DUCTS

VARIATIONS OF MULTIPLE GB

NORMAL GB – ORAL CHOLECYSTOGRAM

NORMAL GALL BLADDER-US

NORMAL GB ANATOMY - CT

MRCP –NORMAL GB AND BILE DUCT

GALL STONES• About 70 % of gall stones are predominantly/purely Cholestrol type • About 30 % of gal stones are Black pigment stones composed of Calcium bilirubinate and

Calcium carbonate

• IMAGING MODALITIES :• X ray : Less than 10 % stones are Opaque on plain Radiograph • large stones shows lamellated , peripheral/Central calcification.

• USG : Highly sensitive in detecting gall stones and it’s the preferred imaging modality • Non Impacted stones tend to mobile , echogenic foci in dependent portion with • posterior acoustic shadowing . (small stones may not shadow ).• Shadowing can differentiate Gall stones from polyps.• In order to evaluate Gall stone mobility patient ca be rolled into new position , left lateral

decubitus. Mobile gall stone will roll into the most dependant position. Gall stones adherent to the wall may not show mobility and don’t show shadowing , can mimic polyp.

• GB filled with Gall stones show DOUBLE ARC SHADOW (Wall Echo Shadow )sign in Gb fossa .

• It consists of Two parallel curved echogenic lines separated by a thin anechoic space with dense acoustic shadowing distal to the deeper echogenic line.

• • •

• CT :• Detects 75% of stones and its seen as intraluminal hyperdense

foci . Sensitivity depends on the make of stones .• Non calcified stones may be isodense to the bile and may not

be visualized/seen as subtle filling defects with a density slightly higher or lower than the surrounding bile. Cholesterol stones may float when Spe Gra of the bile is higher than that of stones .

• target sign: central rounded density: stone surrounding lower attenuating bile or mucosa.

• crescent sign: bile eccentrically outlines luminal stone, creating a low attenuation crescent

• Gall stones with calcium or gas , they can be readily identified. Gall stones containing Gas ( Nitrogen ) within fissures may display A Mercedes Benz sign, which refers to the triradiate appearance of gas density.

• MRI:• Gall stones are recognized as Hypointense filling defects but

may appear hyperintese on T1 weighted imaging. Stones upto 2mm can be detected.

•

• Gall stone Spillage :• Its also called dropped gall stones .• Its complication of Lap Chole and may occur when GB is

perforated during dissection from the liver bed or during the extraction of the GB through the narrow port

• The spilled gall stone may remain in the peritoneal cavity adjacent to the liver or it may migrate to distant sites such as pelvis or pleural space. It can form abscess .It is seen mostly with Bilirubinate stones with viable bacteria.

• Diagnosis on CT is straight forward if the stone is radiopaque (history of lap chole)

Calculus in CBD

CBD Calculi on MRCP

Calculi in GB and CBD

On MRI

GALL BLADDER POLYPLesions that project from the gall bladder wall into the gallbladder lumen are called gallbladder polyps .

They include neoplasms such as adenomas or adenocarcinomas and nonneoplastic lesions such as cholesterol polyps (most common), infl ammatory polyps, and hyperplastic polyps.

Many lesions identified as polyps on USG prove to be small gallstones upon cholecystectomy . Gallstones that are adherent to the gallbladder wall and do not show clear shadowing may mimic polyps .

Features of malignant polyp :•Size greater than 10 mm•sessile, are single,•adjacent wall thickening, or are found in patients older•Seen in Pts with age > 50yrs

• Gallbladder adenomas • Uncommon benign epithelia l neoplasms considered to have

malignant potential.• They are more commonly found in women and may be

associated with Peutz- Jeghers or familial polyposis syndromes .• They are usually solitary (90 %) and may be sessile or

pedunculated

• Cholesterolosis• An accumulation of lipid-laden macrophages in the lamina propria

of the gallbladder, may result in the formation of excrescences called cholesterol polyps.

• Single/Multiple • typically smaller than 10 mm, and enhance with IV contrast. • They may appear to float in the gallbladder lumen on CT due to a

thin stalk that may be imperceptible on CT. They have no malignant potential.

Imaging USG:• Single or multiple, immobile, nonshadowing lesions arising from the

gallbladder wall. • Ultrasonography is unable to reliably differentiate benign from malignant

polyps . Multiplicity and polyps smaller than 10 mm are more suggestive of benignity.

• Gallbladder polyps are differentiated from gallstones by their lack of shadowing and mobility.

CT is signifi cantly less sensitive for detecting polyps compared to ultrasound and it may not be possible to distinguish a polyp from a noncalcified gallstone on CT.

MRI:• polyps are low in signal on both T1- and T2-weighted imaging. • Both benign and malignant polyps may show early enhancement;

however, on 5-min delayed imaging, malignant polyps tend to demonstrate prolonged enhancement, whereas benign polyps show washout.

Acute cholecystitis• Its acute inflammation of the gallbladder. It is the primary complication

of cholelithiasis and the most common cause of acute pain in the right upper quadrant (RUQ).

• Ultrasound• The most sensitive US finding in acute cholecystitis is the presence of

cholelithiasis in combination with the sonographic Murphy sign. Both diffuse gallbladder wall thickening (>3 mm) , wall hyperemia and pericholecystic fluid are secondary findings. 

• CT • Less sensitive for dectecting cholecystitis compared to US but may

show a distended gall bladder with wall thickening ( >3-5 mm)• Mucosal /mural hyperenhancement , pericholecytic Inflammatory fat

stranding or fluid and gall stones • Gall stones might be missed on CT if they are isodense to bile

( cholesterol stones )• CT is more sensitive for dectection of Calcified or gas containing stones

• Liver around Gb fossa may show Transcient Hyperenhancement on post Con

• Arterial phase image owing to reactive hyperemia from acute inflammmation

• This finding can help in differenciating ACUTE Vs CHRONIC Cholecystitis.

• MRI :• In equivocal situations MRI may be helpful • Due to its superior ability to dectect gall stones in bladder neck or cystic

duct • In Young or Pregnant patients with Equivocal signs , MRI is preffered due

to its Lack of ionizing radiation • Features on MRI Distended gall bladder with a thickened , hyperenhancing wall , gall

stones , pericholecystic fat signal intensity changes

HIGLY SPECIFIC FINDING :

Intraluminal wall membranes and wall irregularity indicating Gangrenous / Necrotic Gb and pericholecystic abscess.

Presence of gall bladder wall hyper enhancement and the presence of Focal

Transient liver enhancement adjacent to GB ( Helps to Diff ACUTE vs CHRONIC )

MRI/MRCP:• Higher sensitivity than US • Post Con T1 : Enhancement of thickened GB wall and

pericholecystic fluid • T2 : High signal Edematous GB wall , pericholecystic fluid • MRCP : May see stone obstructing the cystic duct.

ACUTE ACALCULOUS CHOLECYSTITIS• Acute inflammation of gb in absence of stones (10% of all cases of

AC CHOLE )• Ususally seen in Post operative , trauma , Burn patients in ICU

setting , Patient on Total parenteral nutrition

• Imaging features are similar to AC CALCULOUS CHOLECYSTITIS with absence of stones

• CHOLESCNTIGRAPHY: Cholesyntigraphy followed by IV infusion of Cholecystokinin (CCK )

or one of its analogue s , can be used to assess Gb contractibility. An ejection

fraction of <35% on CCK- Cholesyntigraphy is taken to be an indicator of Gb

dysfunction.

•Nuclear medicine• 99mTc-HIDA scintigraphy•HIDA cholescintigraphy in acute

cholecystitis will demonstrate nonvisualization of the gallbladder.  

Distended gall bladder shows odematous wall, calculi and sludge

Chronic cholecystitis• Refers to prolonged inflammatory condition that affects the

gallbladder. It is almost always seen in the setting of cholelithiasis (95%), caused by intermittent obstruction of the cystic duct or infundibulum or dysmotility.

• IMAGING : GB wall thickeningin the presence of gall stones GB may appear normal in size or distended with gall stones

Chronic Cholecystitis can be differenciated from acute by the absence of

a)GB wall enhancement b) Inceased transcient pericholecysitc hepatic enhancement c) Pericholecystic inflammation d) wall hyperemia e) Murphy s sign

• Nuclear medicine• Hepatobiliary scintigraphy may be required to distinguish

acute from chronic cholecystitis and to evaluate gallbladder dysmotility by calculation of the gallbladder ejection fraction.

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

COMPLICATION OF CHOLECYSTITIS • Gangrenous cholecystitis • Emphysematous Cholecystitis • Hemorrhagic Cholecystitis • GB perforation• GB fistula

GANGRENOUS CHOLECYSTITS • Gangrenous/Necrotising Cholecystitis is a severe form of ACC due to

the result of increased GB distension and ischemic mural necrosis caused by

vascular compromise.

• USG : Pronounced irregularity or asymmetrical thickening of the gall

bladder wall , internal membrane echoes resulting from sloughed mucosa and pericholecystic fluid.

Echogenic foci with dirty shadowing consistent with gas within the GB lumen , frank disruption of the GB wall and pericholecystic abscess

• CT: Gas in lumen or wall , discontinuous and or irregular mucosal

enhancement, sloughed intraluminal membranes , irregular or abscent GB wall and pericholecusytic abscess .

•MRI: Lack of GB wall enhancement on contrast enhanced T1 images

suggests gangrenous change. Gangrene produces ulceration , haemorrhage or micro abscess

formation within the GB wall resulting in asymmetry and focal intramural hyperintensity on fat supressed T2 images.

EMPHYSEMATOUS CHOLECYSTITS • Common in men and of that 50 % are diabetics • They result from ischemia of the GB wall associated with proliferation

of gas forming bacteria , including Clostridium perfringes , E Coli • X ray : intramural and intraluminal gas in distended gall bladder

• USG: Intramural gas appears as focal or diffuse bright echogenic lines. Intraluminal gas , in the non dependant portion of the gall bladder

causes a curvilinear , brightly echogenic band with shadowing. Small foci of intramural gas can cause ring down artefact and

mimic adenomyosis .

• CT: Intramural and/or intraluminal gas caused by the gas forming organisms.

• MRI : intramural signal void , which can also be mistaken for calcification or/and

fliud level in gb lumen

GALL BLADDER FISTULE• GB fistulae results from acute cholecystitis coupled with

adhesions and abscess formation.

• Fistulae may form between the gall bladder and neighbouring organs namely

Duodenum (Cholecystoduodenal fistula) Transverse colon (Cholecystocoilc fistula) Common bile duct (Cholecystocholedochal fistula) Stomach (Cholecystogastric fistula) Bile duct and duodenum Choledochoduodenal fistula

GALL STONE ILEUS• Its associated with Cholecytsoduodenal fistula • The gall stone passes into the duodenum by eroding the inflamed gall

bladder wall and leads to small bowel obstruction • Clinical symptoms : RIGLERS TRIAD Pneumobilia Small bowel obstruction Ectopic gall stone usually in right iliac fossa

Gas in biliary tree can be recognised by its branching pattern with gas being more prominent centrally

Gas in portal vein tends to be peripherally located in small veins around the edge of the liver

BOUVERET SYNDROME : Gastric outlet obstruction due to gall stones impacted in the distal stomach or proximal duodenum

Xanthogranulomatous cholecystitis• Xanthogranulomatous cholecystitis is an unusual variant of chronic

cholecystitis, characterized by a lipid-laden benign , destructive , inflammatory process comparable to xanthogranulomatous pyelonephritis.

• Etiology : Rupture of occluded RAS ( Rokitansky –Aschoff Sinuses ) with extrusion of bile into the gall bladder wall that elicits an inflammatory reaction .

• The inflammatory reaction can obliterate soft tissue planes and extend into nearby structures, mimicking tumour invasion.

• IMAGING :• USG : Cholelithiasis and gall bladder wall thickening ( focal or

diffuse ) Most characteristic finding : Presence of hypoechogenic nodules or

bands in the Gall bladder wall .

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

• MRI: focal or diffuse areas of T2 and low T1 signal which shows delayed enhancement with gadolinium.

• It is important for the radiologist to distinguish xanthogranulomatous cholecystitis from gallbladder cancer.

• FEATURES TO DIFFERENCIATE XGN CCS Vs GB CARCINOMA :

• The characteristic CT and MRI fi ndings of xanthogranulomatous cholecystitis—including a patent mucosal line or luminal surface enhancement on CT, and intramural nodules with hypoattenuation on CT or very high signal intensity on T2-weighted images—can be helpful in differentiating the two conditions

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

ADENOMYOSIS Adenomyomatosis of the gallbladder is a common benign condition characterized by proliferation of the gallbladder wall mucosa, which invaginates into the thickened muscular layer and thereby forms intramural diverticula known as Rokitansky-Aschoff sinuses (RAS).

Adenomyomatosis can manifest as focal (usually affecting the fundus), segmental (such as an annular configuration resulting in an “hourglass”), or diffuse gallbladder wall thickening .IMAGING :

USG: Depicts gallbladder wall thickening well. The characteristic, highly specific feature is tiny intramural echogenic foci with “comet tail” reverberation artifact or color Doppler twinkling artifact thought to arise from cholesterol crystals within the RAS.

CT :•Nonspecific abnormal gallbladder wall thickening and enhancement . •If RAS are large enough to resolve, a CT “rosary sign” may appear, formed by mucosal enhancement within the diverticula surrounded by unenhanced hypertrophied gallbladder wall muscle.•CT is limited in the differentiation of adenomyomatosis from gallbladder carcinoma.•SPECIFIC FINDING : The presence of small cystic spaces within the thickened gallbladder wall .

MRI : •The Rokitansky-Aschoff sinuses appear as nonenhancing T1-hypointense, T2-hyperintense intramural lesions . •The “pearl necklace sign” can be identified consisting of small round foci of bright T2 signal within the thickened gallbladder wall.• Postcontrast MRI shows early linear mucosal enhancement of the gallbladder wall in the involved segments. Focal involvement is often present at the gallbladder.

GALLBLADDER CARCINOMA • Adenocarcinoma is the most common histologic type, accounting

for 85% to 90% of cases. Other types are squamous or adenosquamous cell carcinoma

 • The risk factors : Gallstones, congenital abnormal

pancreaticobiliary ductal union, porcelain gallbladder , Chronic cholecystitis , Chronic typhoid infection and UC

 • MODE OF SPREAD• a)Direct extension into adjacent structures such as the liver,

hepatoduodenal ligament, colon, and duodenum . The liver is the most common site of invasion because of its proximity and the lack of serosa in the gallbladder wall where it is adjacent to the liver.

• b)Lymphatic spread to regional and distant lymph nodes is also common in gallbladder carcinoma.

•

• Foramen of Winslow lymph node and the superior pancreaticoduodenal node are the most frequent sites of nodal metastases

• The other pathways of tumor spread c)Hematogenous metastasis to the liver,

• d) intraductal tumor spread e) peritoneal seeding .• Biliary obstruction can be in present gallbladder carcinoma,

because of direct invasion of the bile duct in the porta hepatis, to metastatic lymphadenopathy, or to intraductal spread of tumor .

• IMAGING :• CT :Typical finding include three patterns: • 1)a mass replacing the gallbladder fossa (most common)• 2)an intraluminal polypoid mass• 3)gallbladder wall thickening. • The mass fills most of the enlarged and deformed gallbladder,

obscuring the peripheral enhancement in the early phase and progressive enhancement in the late phase.

• This type of gallbladder carcinoma often invades adjacent structures, including the liver .

• An intraluminal polypoid mass is less common; differentiation ofpolypoid gb carcinoma from benign polyps is based on size, with polypoid gallbladder carcinoma typically larger than 1 cm .

• Most benign polyps, such as cholesterol polyps, and adenomas are small, measuring less than 1 cm.

• The gallbladder wall thickening type of carcinoma may be difficult to distinguish from adenomyomatosis and cholecystitis (especially chronic cholecystitis and xanthogranulomatous cholecystitis)

• MRI :• GB Ca usually have increased signal intensity and poorly

delineated contours on T2- weighted images and either isointense or hypointense signal on T1-weighted images compared with the liver.

• DWI : High b value DWI MRI helps in differenciating Benign from malignant lesions . Malignant lesions shows Higher signal than benign lesions at b value of 1000 s/mm2

• MR cholangiography is especially useful for gallbladder carcinoma associated with anomalous pancreaticobiliary ductal union . Otherwise, the enhancment pattern of gallbladder carcinoma on dynamic MRI is similar to that reported with CT.

• Identifying invasion into adjacent organs , lymphadenopathy or liver mets helps in differenciating GB ca from Infectious/inflammatory causes.

• FDG PET:• Using dual–time point FDG PET Delayed scan shows • Increased lesion uptake and increased lesion-to-background contrast• They also indicated that the diagnostic performance depends on

Creactive protein levels.• False-positive diagnoses of gallbladder carcinoma are still possible

with FDG PET, because benign lesions such as adenomyomatosis and tuberculosis may appear as hot lesions.

Thank You

111SPOTTER 2

•MENINGIOMA: INCREASED VASCULAR SUPPLY TO PARTIALLY CALCIFIED MASSS.

CT ABDOMENBARIUM UGI

113SPOTTER 23

•ANNULAR PANCREAS : NARROWING D2 & CT SHOW GLAND ENCIRCLING D2.

•From left to right: straight flush; pigtail; cobra; and sidewinder. Note the side-ports in some of the catheters.