Biliary System : Biliary System Speaker : Dr. Kishor Ghodke
DMRD DNB Anatomy of Biliary system : Anatomy of Biliary system Anatomy : Anatomy The biliary system consists of the organs and ducts (bile ducts, gallbladder, and associated structures) that are involved in the production and transportation of bile. Transportation of Bile : Transportation of Bile The transportation of bile follows this sequence:
The liver cells secrete bile, bile flow from liver to right and left hepatic ducts.
These ducts drain into the common hepatic duct.
The common hepatic duct then joins with the cystic duct [which drains the gallbladder] to form the common bile duct.
About 50 percent of the bile produced by liver is first stored in gallbladder.
When food is eaten, the gallbladder contracts and releases stored bile into the duodenum to help break down the fats. Anatomy : Anatomy Anatomy : Anatomy GALLBLADDER ANATOMICAL VARIANTS : GALLBLADDER ANATOMICAL VARIANTS Agenesis of the gallbladder is extremely rare, with a prevalence of 0.03–0.07 per cent.
Double gallbladder occurs in about 0.03 per cent, usually with a shared cystic duct, and the accessory gallbladder is often diseased.
Septate GB True gallbladder septae are uncommon and when occurring at the fundus form a Phrygian cap. Slide 8: Septated gallbladder, B; bilobed, C – F; double gallbladder. Slide 9: Common forms of gallbladder ectopia. A. Intrahepatic. B. Left sided. Bilobed Gall bladder : Bilobed Gall bladder GB : Abnormal positions : GB : Abnormal positions The gallbladder abnormal position:
Intrahepatic , Retrohepatic, suprahepatic & left-sided.
Forms of left-sided gallbladder :
The gallbladder lies under the left hepatic lobe , to the left of the falciform ligament
Independent development of a second gallbladder from the left hepatic duct with regression or failure of development of a right gall-bladder
Herniation of the gallbladder through the foramen of Winslow
Associated with situs inversus. Biliary branching pattern : Biliary branching pattern Variations of biliary branching : Variations of biliary branching Variations of biliary branching patterns. The more common are A, B and C. Slide 14: Other variations includes:
The subvesical duct , duct of Luschka both describe an intrahepatic duct running adjacent to the gallbladder fossa.
Unaccompanied by a portal vein branch, and emptying into either the right hepatic or common hepatic duct.
The term ‘cystohepatic duct’ is probably best reserved for small ducts that drain directly into the gallbladder or cystic duct. Modalities of Investigation : Modalities of Investigation Methods of investigation : Methods of investigation Radiographs
CT , Computed tomographic (CT) cholangiography
MRI,Magnetic resonance cholangiopancreatography [MRCP]
Endoscopic retrograde cholangiopancreatography [ERCP]
Percutaneous transhepatic cholangiography [PTC]
Endoscopic ultrasound Radiographs : Radiographs The pathologic gallbladder conditions with characteristic findings that can be diagnosed on plain radiographs.
Gall stone : Only 10% to 15% of gallstones which are sufficiently calcified can be visualized on the plain abdominal radiograph.
Milk of calcium bile /Limy bile Radiographs : Radiographs Gall Stones with Mercedes Benz sign Radiographs : Radiographs Emphysematous Cholecystitis Porcelain Gall bladder Oral cholecystography : Oral cholecystography Oral cholecystography (OCG) relies on the overnight absorption of an oral contrast agent .
The media in common use are sodium ipodate (Biloptin) and calcium ipodate (Solubiloptin). Oral cholecystography OCG : Oral cholecystography OCG Concentration in the gallbladder is dependent upon ingestion and adequate absorption in the gut, take-up in the liver, excretion in the bile, enterohepatic circulation and a patent cystic duct.
Any factor influencing this pathway will result in failure of opacification and a `non-functioning gallbladder'.
Nonopacification of the gallbladder signifies either absence or pathology of the gallbladder provided that the common bile duct is opacified Ultrasonography : Ultrasonography Fasting for a minimum of 6 hrs needed.
Investigation of the jaundiced patient, differentiation of a hepatocellular `medical' from an obstructive `surgical cause.
Ultrasound is often the only investigation necessary in confirming calculous disease.
Accuracy of ultrasound in detection of gallstones is over 98% Ultrasonography : Ultrasonography Computed Tomographic (CT) Cholangiography : Computed Tomographic (CT) Cholangiography The IV agents, such as sodium iotroxate, were used for conventional IV cholangiography using planar tomography.
Adequate contrast excretion relies on near-normal hepatocyte function, so the technique usually fails if bilirubin levels are more than two to three times normal.
This technique involves the IV infusion of an agent with helical CT performed about 30 min later.
Multislice helical CT allows high resolution scanning and multiplanar reformatting. Computed Tomographic (CT) Cholangiography : Computed Tomographic (CT) Cholangiography Magnetic resonance cholangiopancreatography [MRCP] : Magnetic resonance cholangiopancreatography [MRCP] Magnetic resonance cholangiopancreatography (MRCP) is noninvasive and has replaced (PTC) and ERCP.
It relies on heavily T2-weighted sequences that display stationary water as high signal. Multiplanar thin and thick section acquisitions are obtained using fast spin-echo techniques.
Since conventional MRCP is not reliant on contrast excretion it is suitable for jaundiced patients, which is a major advantage compared with CT-IVC. Magnetic resonance cholangiopancreatography [MRCP] : Magnetic resonance cholangiopancreatography [MRCP] More recently MR has been combined with hepatobiliary contrast agents. These agents, which include gadobenate dimeglumine and gadoxetic acid disodium.
Diagnostic pitfalls with MRCP include localized signal voids caused by surgical clips, and intraductal gas or blood.
Bile flow voids may mimic small stones but the former are centrally placed and have less well-defined margins than the latter. Magnetic resonance cholangiopancreatography [MRCP] : Magnetic resonance cholangiopancreatography [MRCP] Endoscopic retrograde cholangio-pancreatography [ERCP] : Endoscopic retrograde cholangio-pancreatography [ERCP] Advantages of ERCP are that both the biliary and pancreatic ducts are studied,
It allows visual assessment of the duodenum and ampulla of Vater and provides an option for biopsy and brushings, as well as interventional procedures .
Complication rates vary depending on the indication for the procedure, the presence of co-existing disease and the experience of the endoscopist, .
The main diagnostic pitfall with ERCP is the underfilling of ducts above a stricture. Endoscopic retrograde cholangio-pancreatography [ERCP] : Endoscopic retrograde cholangio-pancreatography [ERCP] ERCP technique; A, endoscopic injection of contrast medium
into biliary ducts; B, cholangiogram (ERCP image) of a normal biliary tree. Percutaneous transhepatic cholangiography [PTC] : Percutaneous transhepatic cholangiography [PTC] Direct puncture of the intrahepatic ducts using a fine-gauge Chiba needle allows demonstration of the biliary tree.
Technical success is reduced with undilated duct systems and in less experienced hands. Specific indications : Specific indications 1. To define the level and cause of obstruction in patients with dilated bile ducts on ultrasound in the presence of jaundice.
2. Previous surgery with disconnection of the bile duct with drainage through a Roux loop.
3. In defining biliary-enteric or biliary-cutaneous fistulas.
4. In defining the level of a bile leak.
5. To map the biliary tree as a preliminary to establishing external or internal biliary drainage with stent replacement. Hepatobiliary scintigraphy [HIDA scan] : Hepatobiliary scintigraphy [HIDA scan] Hepatobiliary iminodiacetic acid (HIDA) scintigraphy uses a derivative of iminodiacetic acid, a bilirubin analogue, labelled with 99mTc.
It is injected intravenously and serial gamma camera images are obtained over 2–4 h.
It relies on near-normal bilirubin levels although some agents can be excreted with moderate elevations of bilirubin.
Serial image acquisitions show accumulation of the isotope in the liver, bile ducts, duodenum, small bowel and gallbladder (providing it is present and the cystic duct is patent). Technique : Technique Between 2 and 10 mCi of Tc-HIDA is administered intravenously after a 2 hr fast.
Images are acquired over the next hour at 1 min intervals.
The normal 99 'Tc-HIDA scan provides functional and morphological information about
hepatic parenchyma in the first 10 min,
extrahepatic biliary tree by 20 min and
excretion into the bowel by 1 h. Disorders of the gallbladder : Disorders of the gallbladder Disorders of the gallbladder : Disorders of the gallbladder Gallbladder stones
Milk of calcium bile
Gallbladder carcinoma Gall Stones. : Gall Stones. US is the most accurate modality for the diagnosis of gallbladder stones,
Gall stones appear as echogenic foci producing acoustic shadows
Stone mobility is frequently identifiable
Small stones are differentiated from small polyps by the demonstration of mobility or the presence of an acoustic shadow. Sludge : Sludge Sludge on US appears as fine, nonshadowing dependent echoes.
It is composed of calcium bilirubinate granules, cholesterol crystals and glycoproteins.
It is more commonly seen in chronic fasting states.
Sludge resolves spontaneously in 50 per cent of patients and gallstones will develop in 5–15 per cent. Milk of calcium : Milk of calcium Gallbladder bile becomes very viscous, probably as a result of stasis, and contains a high concentration of calcium bilirubinate.
On US it causes diffuse echoes, similar to sludge, but is more echogenic with a tendency to layer out and produce an acoustic shadow Acute Cholecystitis : Acute Cholecystitis In 90–95 per cent of cases, is due to gallstones (acute calculous cholecystitis).
The positive predictive values of stones combined with either tenderness localized to the gallbladder or the presence of a gallbladder wall thickness of >3 mm is more than 90% Acute cholecystitis. The gallbladder contains small stones in the neck (Nos.1–4)
and its wall shows oedematous thickening (5 mm thickness). Acute Cholecystitis : USG : Acute Cholecystitis : USG Other US signs are
Gallbladder over distension
GB Wall thickening , striations and
Occasionally GB wall hyperaemia on Doppler examination. Acute Cholecystitis : CT : Acute Cholecystitis : CT CT is less accurate than US for acute cholecystitis.
The CT findings in acute cholecystitis include :
GB wall thickening,
pericholecystic fluid and inflammatory stranding in the pericholecystic fat
Gallbladder wall enhancement Hepatobiliary scintigraphy in Acute cholecystitis : Hepatobiliary scintigraphy in Acute cholecystitis Hepatobiliary scintigraphy has a high diagnostic accuracy for acute cholecystitis.
A positive result is nonvisualization of the gallbladder, which results from cystic duct obstruction.
Whilst its accuracy is similar to US .
It is more time consuming and does not allow assessment of related organs. Emphysematous Cholecystitis : Emphysematous Cholecystitis This condition has a relatively high mortality rate.
It is more common in men
About 50% are diabetics, and stones are present in less than 50 %.
The diagnosis on plain radiographs and CT, which shows intramural and/or intraluminal gas caused by gas-forming organisms.
On US recognition of the gallbladder difficult and lead to a false-negative result .
Small foci of intramural gas may cause ring-down artefact and mimic adenomyomatosis Chronic Acalculous cholecystitis : Chronic Acalculous cholecystitis US may show contracted gallbladder , GB wall thickening, no stones.
An ejection fraction more than 35 per cent on CCK-cholescintigraphy is generally taken to be an indicator of gallbladder dysfunction . Fig. 24.14 (A) Chronic cholecystitis Xanthogranulomatous cholecystitis : Xanthogranulomatous cholecystitis This condition is characterised histologically by a destructive inflammatory process with varying proportions of fibrous tissue, inflammatory cells and lipid-laden macrophages.
The presence of gallstones is variable.
Its locally invasive nature GB Polyps : GB Polyps The majority of polyps are cholesterol and less often adenomatous.
Cholesterol polyps are usually 2–10 mm in size whereas adenomas can be up to 2 cm.
They appear as small echogenic nonshadowing foci adherent to the gallbladder wall.
Lack of mobility favours a polyp rather than a stone .
Doppler flow within an echogenic lesion differentiates it from tumefactive sludge . GB polyp . Solitary, nondependent and nonshadowing polyp Adenomyomatosis (cholecystitis glandularis proliferans) : Adenomyomatosis (cholecystitis glandularis proliferans) This condition of unknown aetiology has distinct pathological features, with round-cell infiltration, muscle hypertrophy and formation of epithelial mucosal sinuses (Rokitansky-Aschoff sinuses),
It occurs in three distinct types on OCG:
1. A fundal nodular filling defect
2. Strictures which occur at any site within the gallbladder and which become accentuated after gallbladder contraction
3. Epithelial sinuses, which may only become apparent following contraction with contrast within small mural diverticula. GB -Adenomyomatosis : GB -Adenomyomatosis The affected segment often contains bright echoes arising from the cystic spaces, or from small stones or crystals within them, often associated with ‘comet-tail’ ring-down artefacts. Gallbladder carcinoma : Gallbladder carcinoma Adenocarcinoma of the gallbladder is associated with stones in over 90% of patients.
There is a female to male ratio of 3:1.
Porcelain gallbladder and sclerosing cholangitis are predisposing factors.
Characteristically the tumours are scirrhous and locally infiltrative, involving the intrahepatic biliary tree and common duct, with resulting obstruction and jaundice as a common presenting feature.
Involvement of the hepatic artery and portal vein at the porta are the main reasons why curative surgery is often not possible and treatment is palliative. Gallbladder carcinoma : Gallbladder carcinoma It may be seen on imaging as focal or diffuse irregular thickening of the gallbladder wall or as a larger mass in the gallbladder fossa.
Gallbladder stones are present in the majority and may appear to be ‘buried’ in the mass.
The disease tends to spread to lymph nodes around the portal vein relatively early in its course.
It also spreads to the adjacent liver (segments 4 and 5). GB carcinoma : GB carcinoma Polypoidal growth with breach of continuity of the underlying wall (arrow).
(B) Advanced carcinoma extending outside the fundus, with a nodal metastasis
posterior to the pancreatic head (arrow). Cholesterosis : Cholesterosis In this condition there is diffuse deposition of cholesterol on the gallbladder mucosa.
Deposits are of the order of 1-2 mm, multiple and fixed on scanning.
Differentiation from a polyp is not possible.
The condition is generally asymptomatic; the majority of patients develop cholesterol stones Cholesterosis, showing fixed mural defects. Mirrizzi syndrome : Mirrizzi syndrome This syndrome occurs when an impacted calculus within the cystic duct causes acute cholecystitis. Extension of the local inflammatory process involves the common hepatic or common bile duct.
This compressive effect may result in biliary obstruction and jaundice.
Cholecystectomy alone often results in the re-establishing of biliary drainage and relief of jaundice. Bile duct pathologies : Bile duct pathologies Bile duct pathologies : Bile duct pathologies Choledocholithiasis
Choledochal cyst /Biliary cystic disease
Biliary leaks and bile duct injuries
Pancreatic and ampullary tumours Choledocholithiasis : Choledocholithiasis At least 90 per cent of bile duct stones are stones that have passed from the gallbladder, so-called secondary stones.
Primary stones are those that arise in the bile duct and these are pigment stones.
Duct dilatation and acoustic shadowing are each absent in about 30 per cent of cases.
Positive stone diagnosis depends on the demonstration of an intraductal echogenic focus in both the longitudinal and transverse planes
The duct diameter of <4 mm carries a high negative predictive value for choledocholithiasis regardless of the presence of the gallbladder. Choledocholithiasis. Small shadowing stone (arrow) in dilated bile duct. Choledocholithiasis : Choledocholithiasis CT : Stones usually appear as a ring density or soft-tissue density surrounded by lower density bile, or sometimes as uniformly high-density Choledocholithiasis. A distal common bile duct stone (arrow) is
slightly dense compared with the surrounding low-density bile. Choledocholithiasis : Choledocholithiasis ERCP has a high accuracy for the diagnosis of choledocholithiasis .
It does not, however, detect all stones and in one study its sensitivity was 89 per cent
MRCP has a high reported accuracy in the diagnosis of chole-docholithiasis.
The sensitivities of 92 per cent and 94 per cent and a specificity of 99 per cent. . Hepatolithiasis : Hepatolithiasis The great majority of duct stones are extra hepatic.
Intrahepatic stones formation, or hepatolithiasis, may occur in association with common duct stones .
It is often associated with other pathology including benign strictures; primary sclerosing cholangitis (PSC); postoperative, recurrent, pyogenic cholangitis; and Caroli's disease. CT plain – Intrahepatic biliary radical dilatation with biliary calcification. Choledochal cysts : Choledochal cysts Cystic dilatation of the extrahepatic bile ducts is a rare abnormality
Female preponderance of 4:1 = F:M.
The majority are now diagnosed in childhood, with jaundice from obstruction and cholangitis ,duct dilatation, often in patients with non-specific abdominal symptoms.
Rarely, such cysts are so large that their relationship to the biliary tree can only be determined . Slide 63: Choledochal cysts classified in to five types BY Todani’s classification.
There is a relatively high incidence of stone development in the affected ducts .
There is an association with various biliary tumours, most commonly cholangiocarcinoma. Type -I : Type -I Type I -cystic or fusiform dilatation of extrahepatic bile duct.
App. Incidence 79 % Type-II : Type-II Type II –diverticulum
App. Incidence - 3 % Type-III : Type-III Type IlI-choledochocele of intraduodenal common bile duct dilatation .
App. Incidence : 4 % Type-IV : Type-IV Type IV-extra- and intrahepatic cysts.
App. Incidence :13 % Type-V : Type-V Type V-intrahepatic dilatation (4.6%) [Caroli’s Disease]
App. Incidence Type V: 1 %. Biliary Atresia : Biliary Atresia Biliary atresia (BA) is a rare disease characterized by a biliary obstruction of unknown origin that presents in the neonatal period.
Untreated, this condition leads to cirrhosis and death within the first years of life. Biliary Atresia : Biliary Atresia Surgical treatment usually involves an initial attempt to restore bile flow: the Kasai portoenterostomy.
BA remains the commonest indication for paediatric liver transplantation throughout the world. Biliary Atresia : Biliary Atresia Two different forms of BA are identified :-
Syndromic BA (~10%), in which biliary atresia is associated with various congenital anomalies such as polysplenia, asplenia, cardiac or intra abdominal abnormalities.
Non-syndromic BA (~90%), in which biliary atresia is an isolated anomaly. Biliary Atresia : Biliary Atresia Ultrasonography: Ultrasonography of the liver is performed after a 12 hours fast (with an IV fluid infusion).
BA is suspected
if the gallbladder is shrunken despite fasting,
if the liver hilum appears hyperechogenic ("triangular cord sign"), or
if there is a cyst at the liver hilum.
There should be no evidence of bile duct dilatation. Biliary Atresia : Biliary Atresia Cholangiography:
Cholangiography is needed to assess the morphology and patency of the biliary tree.
Biochemical liver function tests show cholestasis Biliary Atresia : Biliary Atresia Hepatobiliary scintigraphy (e.g. HIDA scans) demonstrates a failure of excretion of the radioisotope into the intestine.
Visualisation of small bowel using the isotope 99Tc-DISIDA (di-isopropyliminodiacetic acid) excludes biliary atresia Triangular cord sign : Triangular cord sign The triangular cord sign is a term used to describe the fibrotic, obliterated common bile duct in infants with biliary atresia. USG reveals tubular echogenic cord (arrows). Biliary strictures : Biliary strictures Biliary strictures may be benign and malignant .
Benign biliary strictures
Primary sclerosing Cholangitis [PSC]
HIV cholangiopathy. Post-surgical strictures : Post-surgical strictures Postoperative strictures most often result from cholecystectomy.
They tend to be only 1–2 mm in length
They often involve the common duct.
Duct stones may develop proximal to a stricture.
MRCP has the advantage over ERCP of demonstrating ducts above a complete stricture. Slide 78: ERCP shows a post-cholecystectomy stricture (arrow) which, characteristically, is very short. Primary sclerosing Cholangitis [PSC] : Primary sclerosing Cholangitis [PSC] This is a disease of unknown aetiology, characterised by an inflammatory process affecting the intra- and extrahepatic ducts.
The condition commonly presents in early childhood with features of cholestasis, Primary sclerosing Cholangitis [PSC] : Primary sclerosing Cholangitis [PSC] This is characterized on cholangiography by multiple segments of stricturing involving intrahepatic and/or extrahepatic ducts
Another feature in the common bile duct is diverticula-like out-pouchings
Well-established PSC is associated with areas of atrophy and hypertrophy within the liver, best seen with CT or MRI. Primary sclerosing Cholangitis [PSC] : Primary sclerosing Cholangitis [PSC] Recognised associations is Inflammatory bowel disease (30%).
Severity of extrahepatic involvement may carry a worse prognosis
Cholangiocarcinoma occurs in about 10 per cent of affected patients difficult to diagnose early Primary sclerosing Cholangitis [PSC] : Primary sclerosing Cholangitis [PSC] Primary sclerosing cholangitis : CT-IVC shows multiple intrahepatic and extrahepatic segments of stricturing. Primary sclerosing cholangitis Biliary Stricture: Chronic pancreatitis : Biliary Stricture: Chronic pancreatitis Pancreatitis, both acute and chronic, can produce biliary stricturing caused by fibrosis and/or an inflammatory mass.
Cholangiographically the strictures are typically smooth and tapered, and tend to extend over a few centimeters Bacterial Cholangitis : Bacterial Cholangitis Acute bacterial cholangitis is almost always associated with at least partial bile duct obstruction, most often choledocholithiasis.
Patients present with some or all features of Charcot's triad, namely fever, right upper quadrant pain and jaundice.
Imaging should include US and sometimes CT. MRCP may be used to help identify obstructing pathology .
US may show duct stones or other underlying obstructing pathology and, may show bile duct wall thickening. Slide 86: Recurrent pyogenic cholangitis (RPC), also referred to as oriental cholangiohepatitis, occurs mainly in South-East Asia or its emigrants.
It is characterized by recurrent episodes of cholangitis, bile duct stones, biliary dilatation and strictures.
Although parasites, in particular Clonorchis sinensis, may play a partial role. Neoplastic bile duct pathology : Neoplastic bile duct pathology Neoplastic bile duct pathology : Neoplastic bile duct pathology Cholangiocarcinoma
Malignant biliary stricture
Metastases and lymphoma
Pancreatic and ampullary tumours
Biliary cystadenoma /cystadenocarcinoma Cholangiocarcinoma : Cholangiocarcinoma Cholangiocarcinoma arises from the bile duct epithelium and tends to spread by local infiltration.
Approximately 60 % - perihilar region (Klatskin tumours),
less than 30 % in the distal common duct,
less than 10 % are diffuse or multifocal
Approximately 10 per cent are classified as peripheral, arising within the liver and presenting as an hepatic mass. Cholangiocarcinoma : Cholangiocarcinoma Their appearance on imaging varies with size and pathological type.
Most of the exophytic tumours are less than 5 cm and the infiltrating stenotic tumors are usually less than 1–2 cm. Cholangiocarcinoma : Cholangiocarcinoma On US the tumours appear as nodules or focal bile duct wall thickening.
On CT the nodules are usually isodense or slightly hypodense more easily seen on contrast-enhanced imaging; Slide 93: On MRI the tumours are hypointense on T1 and hyperintense on T2 and show some progressive enhancement on dynamic imaging.
The proximal extent of the stricturing, which critically affects treatment options, is well shown with MRCP Klatskin tumor (cholangiocarcinoma). : Klatskin tumor (cholangiocarcinoma). ERCP shows mild dilatation of the intrahepatic bile ducts and an irregular stricture (arrow) at the bifurcation of the main intrahepatic bile ducts. Metastases and lymphoma : Metastases and lymphoma Metastases and lymphoma may result in hilar or mid/low biliary obstruction.
Cholangiographically they mimic other malignant causes of obstruction. Metastases and lymphoma : Metastases and lymphoma The strictures can be long and may have a characteristic scalloped appearance on cholangiography .
On sectional imaging abnormal soft tissue is usually evident.
Intraductal metastases are rare but may be seen with a variety of tumours, most notably melanoma. Pancreatic and Ampullary tumours : Pancreatic and Ampullary tumours On cholangiography pancreatic carcinoma produces a tight stricture that is often shouldered.
Adjacent strictures of both the bile duct and the pancreatic duct (‘double-duct sign’) are highly suggestive of pancreatic carcinoma . Pancreatic and Ampullary tumours : Pancreatic and Ampullary tumours Biliary cystadenoma /cystadenocarcinoma : Biliary cystadenoma /cystadenocarcinoma These rare tumours of the biliary epithelium
Present as complex,often cystic masses within liver parenchyma which may infiltrate segmental bile ducts .
Histologically a better prognostic group containing ovarian stroma.
There is no radiological criterion by which these may be distinguished. Malignant biliary stricture : Malignant biliary stricture Malignant Biliary Strictures Causes
1. Pancreatic carcinoma
3. Ampullary carcinoma
4. Extrinsic compression
- Primary hepatic tumors or secondary deposits Malignant biliary stricture : Malignant biliary stricture In malignant hilar obstruction , evaluation should include
Proximal extent of stricturing,
Presence of lobar atrophy,
Patency of the portal veins and
Presence of any intrahepatic or local extrahepatic metastases. Malignant biliary stricture : Malignant biliary stricture In malignant low obstruction, usually due to pancreatic carcinoma, the main factors to assess are
Vascular involvement (portal vein, superior mesenteric vein and superior mesenteric artery),
Lymph node metastases and
Hepatic metastases Slide 105: The proximal extent of stricturing is classified according to the modified Bismuth classification in to four types. Figure 36.20 Modified Bismuth classification of malignant hilar biliary obstruction
based on proximal extent of tumour. INTERVENTIONAL TECHNIQUES : INTERVENTIONAL TECHNIQUES Percutaneous cholecystostomy
Percutaneous transhepatic/Endoscopic biliary catheterization/stenting
Biopsy Slide 107: Thank you