Bile is a bi-product of degraded heme part of old red cells.

It is secreted by the liver ,transported through biliary channels to gall bladder where it is stored, concentrated and later delivered to the duodenum.

ANATOMY OF BILIARY TREE

Biliary tree is divided into:

Intrahepatic ducts

Extrahepatic ducts

INTRAHEPATIC DUCTS

These comprise of ductular and canalicular network from the acini . The smallest interlobular ducts join to form segmental bile ducts which finally unite to form the left and right hepatic ducts.

They travel with branches of portal vein & hepatic artery in portal triads.

The Rt.hepatic duct drains four segments of Rt.lobe of liver through two segmental divisions ,an anterior division drains segment 5 & 8 and posterior division drains segment 6 & 7.

The Lt.Hepatic duct drains segment 2,3 & 4 of left lobe.

Caudate lobe has a variable drainage pattern but in majority, 78% drainage is into both main ducts.

EXTRA HEPATIC BILE DUCTS

The right and left hepatic ducts fuse at the hilum ,anterior to bifurcation of the portal vein to form Common Hepatic Duct which is then inserted by cystic duct from the gall bladder and becomes Common Bile Duct

The CBD passes inferiorly posterior to the first part of duodenum and pancreatic head to enter the second part of duodenum along with the main pancreatic duct at Ampulla of Vater

ARTERIAL SUPPLYThree segments of supply.

Supply to the Supraduodenal part is essentially axial from Retroduodenal artery, Rt.hepatic artery, Cystic artery and Gastroduodenal artery.

Hilar biliary ducts recruit their supply from a network in continuity with the Supraduodenal supply.

Retropancreatic part of common bile duct is derived from Retroduodenal artery.

DEVELOPMENTAL INTRAHEPATICBILIARY ANOMALIES

Variations occur: Triple confluence of the Rt.posterior sectoral, Rt.anterior

sectoral and main Left Hepatic duct(12%)

Direct insertion of Rt.sectoral duct into main bile duct(20%)

Insertion of Rt.sectoral duct into Lt.hepatic duct(3%)

Insertion of Rt.posterior sectoral duct into Cystic duct or gall bladder may occur.

Failure to recognise these anatomical variations at cholangiography or surgery may result in biliary leaks or impaired drainage lead to cholangitis.

EXTRAHEPATIC BILIARY ANOMALIES

A number of anomalies with important radiological implications are;

Agenesis of gall bladder.

Bilobar gall bladder.

Folded gall bladder.

Congenital diverticulum.

Duplication of cystic duct with a unilocular gall bladder.

Septum of gall bladder.

Anomalies of gall bladder position i.e it may lie in an intrahepatic, suprahepatic or retrohepatic site or herniate through epiploic foramen.

These anomalies if complicated by disease carry high morbidity.

INVESTIGATIONRadiological investigations comprise of :

Plain radiograph

Ultrasound

Computed tomography

Magnetic resonance imaging

Radionuclide imaging

Indirect cholangiography

Plain Radoigraph

Plain radiograph is usually taken as part of sequence of investigation of abdominal pain.

It gives information about radiopaque stones, mural calcification, mural gas and gas in biliary tree.

ULTRASOUND the first line investigation particularly calculous disease(over

98% accuracy). Preperation:

Fasting for a minimum of 6 hours

Scanning in two positions,supine and left lateral ensures to find any missed calculus.

U/S detects dilated Intrahepatic and extrahepatic ducts, cholelithiasis, cholecystitis, GB polyp, choledochal cyst etc

COMPUTED TOMOGRAPHY

The sensitivity of CT in differentiating hepatocellular from obstructive jaundice and in determining the level and cause of obstruction parallels that of ultrasound.

CT is reserved for those patients in whom there is doubt as to the cause of obstruction and in staging of biliary tumours.

RADIONUCLIDE IMAGING

99mTc-HIDA is used to study the action of biliary tree.TECHNIQUE

Between 2 and 10 mCi of 99mTc-HIDA is administered intravenously after a 2 hr fast. Images are acquired over the next hour at 1min intervals.

Subsequent images may be required at various intervals over 24 hours to evaluate excretion.

The normal HIDA scan provides functional and morphological information about hepatic parenchyma in the first 10 min, the extrahepatic biliary tree by 20 min, and excretion into the bile by 1 hr

INDICATIONS Neonatal and childhood jaundice Cholesystitis Biliary obstruction and Biliary leaks

99mTc-HIDA scan. Biliary obstruction. Activity on the serialimages is concentrated in the liver and none has traversed the biliary tree into the gut. Cardiac activity is shown to decrease as more and more of theactive agent is extracted by and concentrated in the liver.

INDIRECT CHOLANGIOGRAPHY

ORAL CHOLANGIOGRAPHY

It has a limited role in anatomical and functional assessment of gall bladder but the diagnostic accuracy in demonstrating gall stones is upto 90%. The media commonly used is

sodium ipodite (Biloptin),

Calcium ipodite(Solubiloptin).

Small Cholesterol calculi which float in the erect posture (A) Prone (B) Erect

PERCUTANEOUSCHOLANGIOGRAPHY (PTC)

Direct puncture of the intrahepatic ducts using a fine-gauge Chiba needle allows demonstration of biliary tree with relative safety.

INDICATIONS

Obstructed jaundice with or without duct dilatation.

In defining biliary-enteric or biliary-cutaneous fistulas.

In defining levels of bile leak.

To map biliary tree as a preliminary to establish external or internal biliary drainage with stent placement.

ENDOSCOPIC RETROGRADECHOLANGIOPANCREATOGRAPHY (ERCP)

ERCP is a technique that combines endoscopy and fluoroscpyThrough endoscope, inject dyes into ampulla of vater and can see the biliary tree and pancreatic duct

ERCP can be used both for diagnostic and therapeutic purposes.

INDICATIONS Obstructive jaundice Gall stones with dilated bile ducts / Removal of stones Sphincter of oddi dysfunction / Sphincterotomy Bile duct tumors Dilatation of strictures

Risk factors involve in ERCP are:

Pancreatitis

Gut perforation

Sphincterotomy associated bleeding.

OPERATIVE CHOLANGIOGRAPHY

Operative cholangiography prior starting surgical procedure is done commonly at the time of cholecystectomy for:

Exploration of CBD

Anomalous duct anatomy

Developmental disorders of biliary tree.

Postoperative cholangiography through a T-tube is indicated to ensure removal of all stones.

DEVELOPMENTAL DISORDERS OF CHILDHOOD

BILIARY ATRESIA CHOLEDOCHAL CYST CAROLI,S DISEASE

BILIARY ATRESIA

Atresia of the extrahepatic bile ducts in newborn infants of unknown etiology.

Incidence is 0.8-1.0 /10,000 live births. Associated anomalies like polysplenia, situs inversus,

malrotation and absent inferior vena cava occurs in upto 30% of cases.

Presentation is with prolonged conjugated hyperbilirubinaemia.

u/s reveals hypoplastic gall bladder, a cystic cavity at porta and features of cirrhosis early in life.

Treatment is early portoenterostomy.

Severe biliary atresia with obliteration of intrahepatic bileducts. Hyperplastic lymphatics allow some drainage of bile into theconstructed portoenterostomy (Kasai procedure). This is the most common type and carries the worst prognosis.

Choledochal cyst Cystic dilatation of extrahepatic bile ducts in chilldhood

Presented by; jaundice from obstruction and cholangitis. abdominal pain from pancreatitis. Cholangiography reveals a long common pancreaticobiliary

channel.TYPES

TYPE I _ Cystic or fusiformTYPE II _ DiverticulumTYPE III _ Choledochocele of intraduodenal common bile duct.TYPE IV_ Extra and intrahepatic cysts.TYPE V _ Intrahepatic dilatation.

Diagnosis is mainly by u/s and cholangiography. Treatment is redical excision of cyst and hepaticojujenostomy.

Fusiform choledochal cyst with a long common channel andassociated stricture at the pancreaticobiliary junction.

CT of a large choledocal cyst with biliary obstruction

CAROLI,S DISEASE

It is characterised by multifocal, saccular dilatation of intrahepatic bile ducts sparing the extrahepatic ones.

Biliary stasis lead to cholangitis,ductal calculi and liver abscesses.

A specific sonographic apperance is ”central dot” sign, occurs when dilated bile duct segment surrounds the adjacent hepatic artery and portal vein.

It is usually associated with congenital hepatic fibrosis and cystic disease of kidneys called AUTOSOMAL RECESSIVE FIBRO POLYSTIC DISEASE.

Caroli's disease with characteristic strictures and segmental intrahepatic dilated ducts.

ACQUIRED DISORDERS OF CHILDHOOD

INSPISSATED BILE PLUG SYNDROME

SPONTANEOUS PERFORATION OF BILE DUCT

BILE DUCT TUMOURS

CHOLILITHIASIS

BILIARY STRICTURES

CHOLANGIOPATHIES OF CHILDHOOD

Inspissated bile plug syndrome

Infants may present with jaundice secondary to plugs of thickened bile or rarely obstructing calculi ,and acholic stools.

Aetiological factors include prematurity, prolonged parenteral nutrition,hemolysis developmental choledochal anomalies etc

Treatment is saline irrigation at percutaneouscholangiography or surgical intervention.

Cholelithiasis

Cholelithiasis is being increasingly diagnosed in childhood.

Phototherapy,infection,ileal resection hemolytic diseases contribute to this rising incident.

Spontaneous resolution is often reported in infancy, therefore conservativemanagement is advisable.

DISORDERS OF GALL BLADDER

GALL STONES

Upto 17% of adult population have gallstones. About 50% of detected calculi remain asymptomatic over a 10 year period.

Stones may be of CHOLESTEROL

PURE PIGMENT

CALCIUM BILE SALTS

MIXED

CALCULUS CHOLECYSTITIS This results when a calculus obstructing the cystic duct cause

infection of static bile and the gall bladder mucosa. Differentiated into ACUTE CHOLECYSTITIS

CHRONIC CHOLECYSTITIS

RADIOLOGICAL INVESTIGATIONS

PLAIN RADIOGRAPHIt is estimated that only 15% of gallstones are radiopaque.Thedensest stones are of almost pure calcium carbonate described as mulberry stones .They show stellate faceted appearance with gas forming fissures(Mercedes Benz sign)

Calcium carbonate(mulberry) stones

Mercedes Benz' stone; characteristic appearance on the plain embolisationradiograph (arrowheads) and after removal (insert).

on u/s in the acute phase; Echogenic intraluminal foci representing calculi Mural thickening >3mm with a halo around. Peri cholicystic abscess formation. Murphy,s sign, positive local tenderness.

Chronic cholecystitis results in a contracted gall bladder sometimes with obliteration of lumen inspite of fasting state.

U/S AND CECT SHOWING TINY STONES, SLUDGE AND GALL BLADDER WALL THICKENING AS WELL AS ECHOGENIC INFLAMATORY CHANGES

IN ADJACENT FAT

COMPLICATIONS OF CHOLECYSTITIS

Persistent transmural infection may result in a gangrenous gall bladder that may perforate giving rise to either a localised abcess or biliary peritonitus.

An empyema or mucocele may result if there is continuing cystic duct obstruction.

Fistulation of calculus into small or large bowel with associated enteric obstruction is termed GALL STONE ILEUS.

In acute cholecystitis, if local inflammatory process involves the common hepatic or common bile duct, condition is called MIRRIZZI SYNDROME.

PORCELAIN GALL BLADDER

A porcelain gallbladder is a rare disorder in which chronic cholecystitis produces mural calcification.

It is a precancerous condition.

In these patients a prophylactic cholecystectomy has been advocated because of its association with gallbladder carcinoma .

U/S AND PLAIN RADIOGRAPH SHOWING GB WALL CALCIFICATIONS i.e. PORCELAIN GALL BLADDER

Acalculus cholecystitis

Approx. 5% cases of acute cholecystitis occur in the absence of gall stones.

Etiology is multifactorial and includes ischemia, GB wall infection or cystic duct obstruction.

It may occur in very sick patients like after major surgery, extensive trauma and prolonged parentral nutrition .

EMPHYSEMATOUS CHOLECYSTITIS

infection from gas forming organisms like Clostridium Welchiiwithin the GB wall or lumen.

Most often occur in diabetics or immunocompromised patients.

Perforation is 5 times more likely than with calculus cholecystitis.

PLAIN RADIOGRAPH

shows gas shadows from the wall and lumen of GB along with gas-fluid levels demonstrated on erect posture.

SONOGRAPHICALLY

Manifests as very bright reflections from a non dependent part of GB wall. The associated acoustic shadow is usually dirty and in many cases has a demonstrable ring down artifact ,typical sign of gas.

Emphysematous cholecystitis showing (A) gas in the lumen and wall of the gallbladder and (B) a gas-fluid level in the erect posture.

CHOLESTEROSIS

There is diffuse deposition of cholesterol on the gall bladder mucosa.

Generally asymptomatic.

Deposits are usually 1-2mm, multiple and fixed on scanning

ADENOMYOMATOSIS

It is a benign, usually asymptomatic condition that may produce diffuse or focal wall thickening due to round cell infilteration,muscle hypertrophy and mucosal herniations into the muscular layer called Rokitansky_Aschoff sinuses.

Sonographically, the cholesterol crystals deposited in Rokitansky-Aschoff sinuses result in bright reflections and short comet-tail artefacts arising from GB wall

Oral cholangiography reveals three types of pictures , Fundal nodular filling defect Strictures at any site with in gall bladder. Epithelial sinuses, which may only become apparent

following contraction with contrast trapped within small mural diverticula.

Fundal nodule of adenomyomatosis before and aftergallbladder contraction. Note long cystic duct medial to common bile duct,a congenital anomaly.

ADENOMYOMATOSIS SHOWING COMET-TAIL ARTEFACTS FROM THE SUPERFICIAL WALL OF GALL BLADDER

GALL BLADDER POLYPS

It is a benign, usually asymptomatic condition that may produce cholesterol polyps, which are usually small and are the most common polypoid lesion of gall bladder.

SONOGRAPHICALLY

Appear as a non-mobile, non-shadowing “ball on the wall”.

Gall bladder polyp fixed to the ventral wall of the gallbladder.

GALL BLADDER CARCINOMA

Adenocarcinoma of gall bladder is associated with stones in over 90% of cases.

Female to male ratio is 3: 1

Porcelain gall bladder and sclerosing cholangitis are predisposing factors.

RADIOLOGICALLY

U/S and CT may demonstrate a soft tissue mass within and adjacent to the gall bladder, often with direct extension into related liver segments.

Cholangigraphy reveals biliary stricturing often with intrahepatic ducts dilatation.

GB CARCINOMA WITH MARKED GENERALISED WALL THICKENING WITH FEW CALCULI REPRESENTING FILLED LUMEN/CE-CT IMAGE SHOWS THICK WALLED

GALL BLADDER WITH LOCAL INFILTERATION IN ADJACENT LIVER PARENCHYMA

DISORDERS OF BILE DUCTS

COMMON BILE DUCT AND INTRA HEPATIC STONES

The spectrum of presentation of common duct stones is wide, ranging from septicemia resulting from untreated biliary obstruction and cholangitis to an incidental finding on u/s.

May accompanied by Gall bladder stones.

Very large gallstone (arrow) in dilated bile duct shown at ERCP.

‘Meniscus’ sign of impacted stone (arrow) in bile duct.

BENIGN BILIARY STRICTURESPOST SURGICAL STRICTURESFour main groups of operation carry the risk of stricture formation;

Cholecystectomy (open or laproscopic); Bile duct injury,with transection or devascularisation , may result in a post operative bile leak or stricture formation, site of cystic duct insertion is at highest risk.

Biliary disconnection and drainage of the bile ducts;Roux loop anastomosis to the common hepatic duct and portoenterostomy (Kasai operation) carry a risk of anastomosis stricturing.

Hepatic resection;These operations carry the risk of arterial devascularisation of hepatic artery.

Transplantation;An anastomotic stricture will occur in 5-14 % of liver transplants.

Stricture of a hepaticojejunostomy.Benign postcholecystectomy stricture of common duct (arrow). Typical site at the level of ligation of cystic duct.

CHRONIC PANCREATITIS

Any cause pancreatitis may result in a low bile duct stricture and biliary obstruction.

BLUNT OR PENETRATING LIVER TRAUMA

Injury to bile duct or gall bladder occurs in approx. 5% of liver trauma cases leads to biliary leaks and stricture formation.

PRIMARY SCLEROSING CHOLANGITIS

This is a disease of unknown aetiology, characterized by an inflammatory process affecting the intra and extra hepatic ducts.

The condition may occur at any age. Biliary cirrhosis and hepatic failure ensue

There is a predisposition of developing bile duct cancer.

CHOLANGIOGRAPHY demonstrates multifocal stricturing of bile ducts. Strictures of extrahepatic bile duct may be long or short and multiple. Severity of extra hepatic involvement carry worse prognosis.

U/S & CT may demonstrate segmental duct dilatation and increased periductal reflectivity. Regional lymphadenopathy may be seen ,this may be associated with features of cirrhosis and portal hypertension.

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

PARASITIC INFECTION The common parasites which infest the biliary system are; CLONORCHIS SINENSIS:

This is endemic in South-East Asia, and enters the human body from undercooked and contaminated fish. Live worms within the biliary tree cause periductal fibrosis and stone formation. However upto 75% patients remain asymptomatic.

ASCARIS LUMBRICOIDESEndemic in Asia,Africa and South America. This worm infests the small bowel. Upto 10%patients show biliary infestation, among these 40% will have significant complications. Septic cholangitis with biliary abscess, cholecystitis with empyema and biliary strictures are the sequelae which carry highest morbidity

ECCHINOCOCCUS GRANULOSUSIn hydatid disease of liver, biliary manifestations like

cholangitis and jaundice result from rupture of the cyst into bile duct. Diagnosis is confirmed by CT and ultrasound.

ENTAMOEBA HISTOLYTICAAmoebiasis may produce liver abscess which

communicate segmental bile ducts producing cholangitis.

Ascoris lumbricoides. Ascaris worm in the biliary ducts.

Cholecystostomy tube study showing multiple worms extending from commonbile duct into duodenum.

TUMOURS OF BILE DUCT

CHOLANGIOCARCINOMA/KLATSKIN

This develops at young age mostly presents under the age of 50.There is male preponderance.

Slow growing, locally invasive tumour with frequentinvolvement of hepatic artery and portal venous system. Distant metastasis is not common, occurs in only 12% of patients.

Tumour prognosis is poor with a survival of only 2 months if untreated.

Cholangiocarcinoma of the hilum with a characteristic stricture involving the confluence of the main left and right hepatic ducts.

Ampullary and Pancreatic carcinoma

Ampullary and Pancreatic carcinoma. These are the most common causes of a malignant bile duct

stricture.

Indications for radiological assessment are, Define site and size of tumour. Confirm a tissue diagnosis by guided biopsy. Determine operability by excluding, local involvement of

vessels, regional lymphadenopathy ,ascites and distant metastasis .

Billiary cystadenoma and Cystadenocarcinoma. These are rare tumours of biliary epithelium present as

complex, cystic masses within liver parenchyma which may infiltrate segmental bile ducts.

Radiological assessment is based on determining segmental distribution and vascular relationships.

Low common bile duct stricture, with characteristic features of extrinsic compression from a pancreatic mass (arrow).

‘Double duct ‘ sign. Concomitant strictures of pancreatic duct and bile duct (arrows) diagnostic of carcinoma of head of pancreas.

INDICATIONS OF ENDOSCOPIC SPHINCTEROTOMY

CBD stones with or without GB stones

CBD stones following cholecystectomy with or without a T-tube in place.

Ampullary carcinoma

Malignant bile duct strictures prior to stent insertion

Benign papillary stenosis

Post surgical strictures before dilatation or stent placement

Choledochal fistula

Choledochocele.

INDICATIONS OF STENTING FOR BENIGN BILE DUCT DISORDERS

Early structuring or anastomotic leak following liver transplant.

As a preclude to definitive surgery in iatrogenic transection of bile duct with biliary leak.

Failed stone extraction or a large impacting stone associated with biliary obstruction

Benign strictures in patients unfit for surgery.

Recurrent anastomotic strictures following surgery.

TYPES OF STENT

PLASTIC STENTS: They are made of Teflon

METALLIC STENTS: They are further divided into

Self-expanding stents(Rosch-Z stent)

Balloon expandable stents(Palmaz-stent)

ANGIOGRAPHIC INTERVENTION The main indication of angiographic intervention is

embolization in the presence of haemobilia.Patientpresent with jaundice and GI bleeding with malena, could be due to

Blunt or penetrating liver injury Liver tumours Vascular malformations Iatrogenic trauma, either surgical or following

percutaneous liver biopsy Multiorgan failure with DIC. ULTRASOUND shows reflective material within a

dilated gall bladder and bile duct. ENDOSCOPIC CHOLANGIGRAPHY demonstrate clot

with in Bile duct and bleeding visible at the papilla.