imaging in biliary tract presentation...

Imaging of biliary tract presentation

1. Imaging of Biliary Tree Moderators: Dr . BHAGYARAJ Presenter: Dr . SEEMA

2. GALL BLADDER Normal: Length: 10cm Diameter: 3cm-5cm Capacity: 50mL Wall thickness: 2mm-3mm Wall epithelium: Simple columnar Position: GB fossa between (R) and (L) hepatic lobes on the inferior surface of liver. CBD: Normal: 4-6mm or less 6-7mm: Equivocal 8mm: Indicative of duct dilatation Increases with age

3. Normal Biliary Anatomy and Variants: The biliary tree is divided into intra–hepatic and extra-hepatic bile ducts. Bile canaliculi unite = Segmental ducts Segmental combine = Sectoral ducts The right anterior sectoral and posterior sectoral ducts unite to form RHD. Left hepatic Duct is Formed by the union of the segment II, III, IVa , and IVb ducts.

4. INTRAHEPATIC BILIARY RADICLES IHBR –VARIANTS

5. EXTRAHEPATIC BILIARY RADICLES

6. Common Variations CYSTIC DUCT – CHD UNION Uncommon Variations

7. EXAMINATION TECHNIQUE PLAIN RADIOGRAPH USG FATTY MEAL OR CHOLECYSTOKININ SONOGRAPHY MDCT MRI CHOLANGIOGRAPHY Oral extrahepatic cholangiography Oral CT cholangiography IV CT cholangiography Percutaneous transhepatic cholangiography Transcholecystic cholangiography ERCP MRCP Secretin induced MRCP Intra-operative cholangiography Post-operative cholangiography HEPATOBILIARY SCINTIGRAPHY

8. Normal Cholangiography Anatomy The cystic duct, CHD, and CBD are routinely opacified. Second- and third-order branches are usually seen. Normal diameter of IHBR : 1 to 2 mm. Normal CD diamter : < 8mm The normal intrahepatic ducts branch regularly and smoothly. The extrahepatic bile duct is a smooth-walled, tubular structure extending from the porta hepatis to the duodenum. Distally, the intramural segment may be slightly narrowed and should not be confused with stricture.

9. Normal Cholangiography Anatomy When it is partially relaxed, the choledochal sphincter can create a wavy or narrowed appearance that may be mistaken for ampullary stenosis or neoplasm. When choledochal sphincter is contracted, its upper rounded border produces a pseudocalculus defect - Mimick an impacted stone - disappears spontaneously after IV injection of glucagon, which relaxes the sphincter. Contrast material should flow freely from the CBD into the duodenum during normal cholangiography. Normally, no splaying or crowding of ducts, caliber irregularity, strictures, or filling defects are seen.

10. ANATOMICAL VARIANTS GALLBLADDER . STRUCTURAL VARIANTS : -gallbladder agenesis, -double gb -True gb septa POSITIONAL VARIANTS: - retrohepatic gb - suprahepatic gb -left sided or intrahepatic gb

11. GALLBLADDER DISORDERS GB STONES: Gb stones are asymptomatic in about 80% , about 15% develop symptoms over 15 years. Predominantly cholesterol type: 70% Black pigment stones composed of calcium: 30%

12. Usg : Echogenic foci producing acoustic shadows and mobility of stone is frequently seen Non-visualization of GB:- Presvious cholecystectomy Non fasting state- collapsed gb Abnormal gb postion Emphysematous gb Gb completely filled with stones( double arc shadow)

13. Gb sludge Commonly seen in usg as fine non shadowing dependent echoes Composed of calcium bilirubinate , cholesterol crystals, glycoproteins TUMEFACTIVE GB SLUDGE: Non mobile polypoid mass in GB that does not move despite of positional change in patient.

14. Milk of calcium bile k/c/a limy bile, uncommon condition in which bile becomes viscous- result of stasis, high conc. Of calcium bilirubinate . Usg – diffuse echoes, similar to sludge but is more echogenic with a tendency to layer out and produce an acoustic shadow. Ct—layering high density material

15. CHOLECYSTITIS Acute cholecystitis is the most common cause of right upper quadrant pain. It results from persistent obstruction of the cystic duct or gallbladder neck, with distension of the gallbladder and increased intraluminal pressure. Diagnostic criteria for acute cholecystitis Local sign of inflammation (Murphy sign; pain, or tenderness in right upper quadrant) Systemic sign of inflammation (fever, elevated C-reactive protein level, elevated white blood cell count). Confirmatory imaging findings.

16. USG: Most specific sign Demonstration of stone impacted in the gall bladder neck or cystic duct. Sonographic murphy's sign. Less specific sign Gallbladder distension.(diameter >4cm). Gall bladder wall thickening.(>3mm) Pericholecystic fluid. Presence of intraluminal material such as sludge. Hyperaemic gall bladder wall.

17. Collapsed GB Acute cholecystitis complicates chronic cholecystitis, when there may be mural fibrosis impeding distension. In case of perforation GB will be collapsed. The CT findings of acute cholecystitis have been divided into major and minor criteria Major findings - calculi, mural thickening of the gallbladder, pericholecystic fluid, and subserosal edema . Minor findings - gallbladder distension and sludge.

18. Pericholecystic fluid tends to be more focal and irregularly marginated, whereas mural thickening is concentric. Punctate foci of contrast enhancement corresponding to enhancing vessels within the gallbladder wall may be observed. A target appearance corresponds to an inner layer of enhancing mucosa and an outer layer of enhancing serosa with hypoattenuating submucosal edema between the two.

19. An ancillary CT finding of gallbladder inflammation is increased contrast enhancement in the liver parenchyma adjacent to the gallbladder.

20. Mri : MRCP - is sensitive in the diagnosis of choledocholithiasis. gallbladder wall edema is manifested as high signal intensity on T2-weighted images. Contrast-enhanced T1-weighted images - enhancement of the wall. Transient pericholecystic hepatic enhancement.

21. Acalculous Cholecystitis Risk factors : major surgery, severe trauma, sepsis, TPN, diabetes, atherosclerotic disease, and HIV infection. In non-hospitalized patients, it is more common in elderly male patients with atherosclerotic disease. Pathogenesis - Bile stasis, gallbladder ischemia, cystic duct obstruction, and systemic infection.

22. USG Gall stones are absent. Gallbladder wall thickening, distension, and sludge. Sonographic Murphy sign unreliable.

23. Complications of Acute Cholecystitis GANGRENOUS CHOLECYSTITIS Gangrenous cholecystitis is a severe form of acute cholecystitis associated with vascular compromise and intramural hemorrhage , necrosis, and intramural abscess formation. More common in men, patients of advanced age, those with cardiovascular disease.

24. On USG Heterogeneous, striated thickening and irregularity of the gallbladder wall and intraluminal membranes resulting from desquamation of the gallbladder mucosa. The irregular or asymmetric thickening of the gallbladder wall probably results from ulceration, hemorrhage , necrosis, or micro-abscess formation. Sonographic murphy's sign may be absent because of denervation of gall bladder.

25. Irregular or lack of gallbladder wall enhancement. Intraluminal membranes resulting from desquamation of the gallbladder mucosa, hemorrhage , irregularity or disruption of the gallbladder wall and pericholecystic abscess. Gas in gall bladder wall or lumen.

26. HEMORRHAGIC CHOLECYSTITIS Usg : Blood in the gallbladder lumen can be recognized as hyperechoic material that demonstrates greater echogenicity than sludge. Clotted blood may appear as a clump or mass adherent to the gallbladder wall or heterogeneous echogenic material. As the hemorrhage evolves, the clot may become more cystic in appearance.

27. CT: Increased density of bile noted. A fluid-fluid level may be observed. If there is active bleeding at the time of contrast-enhanced CT, this may appear as active extravasation of intravenous contrast material inside the gallbladder lumen. MRI: Blood products appear as high signal intensity within the gallbladder lumen on T1-weighted images and moderate to high heterogeneous signal intensity on T2-weighted images.

28. EMPHYSEMATOUS CHOLECYSTITIS Cystic artery compromise is thought to promote the proliferation of gas-producing organisms in an anaerobic environment and penetration of gas into the gallbladder wall. USG: A small amount of gas in the wall may appear as an echogenic focus with associated ring-down or comet-tail artifact. Larger amounts of gas and intraluminal gas may appear as a curvilinear arc of increased echogenicity with associated “dirty” posterior acoustic shadowing.

29. CT : Gas within the gallbladder wall or nondependent portion of the lumen. Extension into the pericholecystic soft tissues. Free intra-peritoneal gas indicates associated free gallbladder perforation.

30. MRI A signal void in the nondependent portion of the gallbladder and intermediate signal intensity fluid in the dependent portion of the gallbladder, representing a gas-fluid level. A low signal intensity rim surrounding the gallbladder, indicating gas in the gallbladder wall Regions of very low signal intensity in the pericholecystic soft tissues, indicating extra-luminal gas due to perforation.

31. GALL BLADDER PERFORATION Gallbladder perforation can occur in the setting of cholelithiasis, cholecystitis, trauma, neoplasm, steroid use, or vascular compromise. Most common site – Fundus of gall bladder. Perforation is most often a complication of severe acute cholecystitis. Gallbladder perforation has been classified into three types: (1) acute free perforation into the peritoneal cavity. (2) sub-acute perforation with pericholecystic abscess. (3) chronic perforation with cholecystenteric fistula formation.

32. USG Gallbladder wall is irregular or ill-defined with focal or global loss of its normal sono -reflectivity. There is a large amount of pericholecystic fluid or a loculated pericholecystic collection. Focal defect in the wall of the gallbladder.

33. CT: Interruption of the gallbladder wall or a focal mural defect. Pericholecystic or intrahepatic abscess and spilled stones. Free gallbladder perforation is identified when there is free intra-peritoneal fluid corresponding to bile.

34. Chronic Cholecystitis Intermittent obstruction of the cystic duct or neck as well as gallbladder dysmotility. Chronic inflammatory changes cause the gallbladder wall to become thickened and fibrotic, and with increasing fibrosis, the gallbladder eventually becomes shrunken and distorted. ULTRASOUND Gallstones and thickened gallbladder wall with contraction of the gallbladder that persists in the fasting state. CT Increased peri-hepatic contrast enhancement in acute cholecystitis can be helpful in differentiating acute from chronic inflammation.

35. CHRONIC ACALCULOUS CHOLECYSTITIS Characterized by recurrent biliary colic in a patient without radiographic evidence of gallstones. Cholecystokinin cholescintigraphy A decrease in gallbladder ejection fraction is a common feature of both calculous and acalculous chronic cholecystitis. Cholecystectomy is the treatment of choice.

36. XANTHOGRANULOMATOUS CHOLECYSTITIS Chronic gallbladder infection, usually in the setting of cholelithiasis, with mural micro-abscesses that involve r okitansky - Aschoff sinuses. This may result from obstruction of gallbladder outflow, extravasation of bile into the gallbladder wall, and mucosal ulceration. Histiocytes accumulate in the gallbladder wall as a reaction to the extravasated bile, xanthogranulomatous nodules form in addition to extensive fibrous reaction.

37. USG- -The gallbladder wall is often markedly thickened and irregular with loss of normal planes with adjacent structures. Hypoechoic band around the gallbladder. The gallbladder often becomes adherent to adjacent organs and may be associated with fistula formation.

38. GALL BLADDER MUCOCELE K /C/A gallbladder hydrops, result from chronic gb obstruction without superimposed infection,allowing accumulation of large volumes of sterile mucinous fluid. Impacted stones> polyp,tumor . Gb markedly distended,fluid -filled , may represent mass

39. Porcelain gallbladder Peripherally calcified gb wall—seq of chr.cholecystitis May be in association with gb carcinoma. Prophylactic cholecystectomy needed. Usg – echogenic gb wall, gall stones + Ct– focal/diffuse calcification following the contour of the gb wall.

40. Hyperplastic cholecystoses Spectrum of non neoplastic proliferative disorder caused of cholesterol- laden macrophages within wall of gb ranging from abnormalities of the gb wall ( adenomyomatosis and strawberry gb ) to gb polyps extending into the lumen.

41. Adenomyomatous hyperplasia k /c/a cholecystitis glandularis proliferans - characterized by thickening of gb wall due to epithelial and smooth muscle hyperplasia,with cystic epithileal invaginations into the wall (ROKITANSKY-ASCHOFF SINUSES),and these spaces may contain small stones. Usg – comet tail artifact Ct– focal wall thickening with enhancement Mri – focal, bubbly T2 HS thickening along the gb fundus .

42. Gallbladder polyps Most are benign cholesterol polyps. <5% may be pre-malignant adenomas. Usually asymptomatic, may present with right UQ pain or cholecystitis if obstruct the cystic duct. Risk for malignancy- size>10mm rapid growth, single > multiple,sessile >pedunculated , stones +, PSC , age>60yrs.

43. Usg - small echogenic non shadowing foci adherent to gb wall CECT- differential malignant from benign by demonstrating wall destruction with rapid washout.

44. BILE DUCT PATHOLOGIES Choledochal Cysts : Congenital cystic dilatation of any portion of bile duct. Predispose patients to conditions like cholestasis, choledocholithiasis, cholangitis, pancreatitis, malignancy.

45. Todani Classification:

46. Diagnosis: Usually diagnosed in childhood; 20% identified in adulthood. Can be detected with US, but MRCP is the optimal modality to evaluate the extent of involvement and the pancreaticobiliary junction. Use of MRI: Hepatobiliary MRI contrast agents confirm communication of saccular cysts with the biliary tree. Helps exclude other lesions like mucinous cystic neoplasms.

47. Caroli disease: type V choledochal cyst Autosomal recessive condition of ductal plate malformation large intra-hepatic ducts. Multifocal saccular dilatation of the intrahepatic ducts “ caroli syndrome”: caroli disease coexisting with congenital hepatic fibrosis due to abnormal formation of the small intrahepatic ducts and polycystic kidney disease. Imaging appearance: segmental cystic dilatation of intrahepatic bile ducts-from focal to diffuse involvement.

48. Demonstration of communication with intrahepatic ducts on t2-weighted MRCP images. OR use of hepatobiliary contrast material differentiates it from parenchymal and peribiliary cysts. Central dot sign: punctate enhancement formed by portal vein and hepatic artery branch vessels surrounded by dilated intrahepatic duct, helps differentiate caroli disease from other cysts. DD: cholangiocarcinoma intraductal papillary mucinous neoplasm of the bile ducts (IPNB) Complications: causes bile stasis Biliary stones Recurrent cholangitis Abscesses Cirrhosis Cholangiocarcinoma Treatment: Focal Caroli Disease: Partial hepatectomy. Diffuse Caroli Disease: Liver transplant may be necessary.

49. CHOLEDOCHOLITHIASIS : most common cause of biliary dilatation. Often secondary to stone passage from the gallbladder(16%) primary stone formation (typically pigment stones) is rare and caused by stasis or infection. Stones smaller than 5 mm are often asymptomatic and larger ones can cause cholangitis or pancreatitis. Ultrasound (US) : stones appear as echogenic filling defects with posterior shadowing. Intraluminal debris, hemorrhage, or neoplasm can mimic non-shadowing stones but are usually less echogenic.

50. Computed tomography (CT): appears as a central or dependent filling defect in the common duct with surrounding low-attenuation bile. S tone attenuation depending on the composition. Biliary dilatation with abrupt duct cutoff may indicate a ct -occult stone, resembling an obstructing neoplasm. On Magnetic Resonance Imaging : Biliary stones are T2 hypointense and T1 variable. Cholesterol stones are hypointense; pigmented stones are hyperintense on T1.

51. MIRIZZI SYNDROME : painless jaundice, cholangitis, cholecystitis Refers to extrahepatic duct obstruction from extrinsic compression. caused by an impacted gallstone in the gallbladder neck or cystic duct. Predisposing Factors: long cystic duct running parallel to the extrahepatic duct with low insertion. Diagnosis: imaging shows biliary dilatation proximal to the mid extrahepatic duct without a common duct stone or mass. Confirmed by identifying extrinsic compression of the extrahepatic duct by a stone in the gallbladder neck or cystic duct.

52. Gallbladder Cancer and Mirizzi Syndrome: Gallbladder cancer can coexist with gallstone-related Mirizzi syndrome in up to 5.3% of cases. Associated with biliary stasis and chronic inflammation. Suspect cancer when there is enhancing irregular wall thickening or an intraluminal mass.

53. Cholangitis and Ischemic Disease ACUTE BACTERIAL ("ASCENDING") CHOLANGITIS: Causes and Mechanisms: Caused by a gram-negative bacterial infection, Frequently associated with choledocholithiasis. Mechanisms: retrograde contamination from the gastrointestinal tract, seeding from the portal vein, or percutaneous biliary procedures. Symptoms: Characterized by the Charcot triad: fever, pain, and jaundice. May progress to Reynolds pentad: lethargy and shock.

54. Imaging Findings: biliary inflammation and helps identify obstruction and complications. Ultrasound (US) may show ductal dilatation. CT or MRI better identifies the cause of obstruction. Intrahepatic ductal dilatation is usually present, with extrahepatic dilatation depending on the obstruction level and Bile duct wall thickening. Periductal edema appears as periductal hypoattenuation on CT and T2 hyperintensity on MR images. Heterogeneous hepatic hyperenhancement during arterial phase imaging can occur due to compensatory arterial flow from inflammation-related venous congestion or biliary stasis.

55. Recurrent pyogenic cholangitis: chronic biliary inflammation due to recurrent infection. Leads to strictures, dilatation, and hepatolithiasis. Causes: Clonorchis or Ascaris parasites. Imaging Findings: The central intrahepatic ducts are typically disproportionately dilated, with abrupt peripheral tapering ( ie , the “arrowhead” sign) and/or short strictures. On MRCP, stones appear as filling defects in ducts, forming the "missing duct" sign. Acute inflammation episodes may show ductal wall thickening and hyperenhancement. Complications: Abscesses Hepatic atrophy and cirrhosis: lateral left lobe and posterior right lobe. Cholangiocarcinoma: up to 5% Elevated risk of hepatocellular carcinoma, especially if cirrhosis is present.

56. IMMUNOGLOBULIN G4 (IGG4)–RELATED SCLEROSING CHOLANGITIS:- Benign autoimmune cholangitis Transmural lymphoplasmacytic infiltrate in the biliary walls and peribiliary tissue/fibrosis. Manifests as asymptomatic/ jaundice and abdominal/discovered with autoimmune pancreatitis. Elevated serum IgG4 level (≥135 mg/dL) Imaging: Affects any level of the biliary tree, with the intrapancreatic portion of the common duct usually involved. Strictures show circumferential smooth wall thickening / homogeneous delayed enhancement. But, tend to be longer than PSC strictures and multiorgan involvement (pancreatic, gall bladder, renal, salivary gland, retroperitoneal fibrosis) provides diagnostic clues. Preservation of the lumen in thickened segments is common.

57. PORTAL CHOLANGIOPATHY: extrahepatic portal vein occlusion, leading to the formation of extensive peribiliary collateral veins in the porta hepatis leading to biliary morphologic changes and potential obstruction. VARCOID TYPE FIBROTIC TYPE MIXED TYPE extrinsic compression from enlarged collateral vessels. portal vein thrombus PORTAL VEIN THROMBOSIS Irregular bile duct contours with multiple areas of stricture and dilatation. smooth indentation of the extrahepatic bile duct smooth, localized strictures thickened common bile duct walls a spreading along the duct- pseud-ocholangiocarcinoma. intrahepatic and extrahepatic ducts.

58. ISCHEMIC CHOLANGIOPATHY: ischemia, stricture, and occasional necrosis of bile ducts Blood supply: hepatic arteries via the peribiliary arterial plexus. Causes of Ischemia: - Arterial complications from liver transplant or other hepatobiliary surgeries. - Transarterial interventions. - Large artery stenosis, occlusion, or microangiopathy due to inflammation and rejection.

59. Radiologic Findings : Single or multiple short-segment non-anastomotic biliary strictures + duct dilation + occasional bilomas. Ischemic Cholangiopathy Patterns after Liver Transplant: DIFFUSE NECROSIS MULTIFOCAL PROGRESSIVE CONFLUENT DOMINANT MINOR FORM Severe changes involving most of the biliary tree Stenoses of second order and peripheral ducts Worsen over time Strictures and casts at the biliary confluence Mild, non-progressive abnormalities; retransplant. retransplant. Billiary stenting Rarely re-transplant No intervention needed

60. Primary Sclerosing Cholangitis Chronic cholestatic liver disease of unknown cause. 20 to 30 years 2 : 1 male-to-female predilection 70% of patients with PSC have IBD (Ulcerative colitis in 87%) . In patients with ulcerative colitis, 3% to 7.5% have or will develop PSC Hepatobiliary disease precedes the clinical onset of the bowel disease in some patients. 72

61. Clinical features and lab investigations C/F: 25% of patients with PSC are asymptomatic at presentation Fatigue, pruritus, jaundice, right upper quadrant pain, and hepatosplenomegaly. Raised cholestatic enzymes ( ALP and GGT) Serology: 80% have perinuclear antineutrophil cytoplasmic antibodies called antimitochondrial antibodies ; Antinuclear antibodies and anti–smooth muscle antibody are found in 20% to 50% of PSC patients. 73

62. THE DIAGNOSTIC CRITERIA FOR PSC Typical radiographic appearance of cholangiographic abnormalities Appropriate clinical, biochemical, and histologic findings obtained from liver biopsy Exclusion of secondary causes of sclerosing cholangitis 74 PSC Imaging Manifestations: BILIARY DUCTAL CHANGES FLUOROSCOPIC CHOLANGIOGRAPHY (ERCP) The most important and most characteristic radiographic findings are seen at fluoroscopic cholangiography Multiple segmental strictures involving both the intrahepatic and extrahepatic bile ducts are the hallmark of PSC. 1/4 th of cases – only intrahepatic bile ducts are involved

63. In the early phases of PSC, Normal or less-involved duct segments may alternate with segmental strictures, producing the classic beaded appearance . From 1 to 2 mm (so-called band strictures) to several centimeters Strictures usually occur at the bifurcation of bile ducts and are out of proportion to upstream ductal dilation. 75

64. 76 When the periductal fibrosis worsens, the bile ducts take on a “pruned tree” appearance that reflects peripheral duct obliteration.

65. USG Concentric echogenic mural wall thickening and duct dilation of the CBD or the intrahepatic ducts in a smooth or irregular manner. Bright echogenic portal triad Thickened bile ducts appear as two parallel echogenic lines with a central hypoechoic stripe. Bile duct wall thickening in PSC usually measures 2 to 5 mm . Gallbladder luminal sludge or stones and inflammatory polyps can be present. 77

66. 78 Disproportional dilation of segmental intrahepatic biliary duct with focal constrictions Mural contrast enhancement of the extrahepatic bile ducts can be seen Intrahepatic bile duct calculi are present in approximately 8% of patients with PSC. Upper abdominal lymphadenopathy (nonspecific)

67. MRCP Biliary tree: Multifocal segmental strictures alternating with normal or slightly dilated bile duct segments Periductal inflammation and fibrosis prevent the ducts from dilating; Therefore, high-grade strictures present with only minimal proximal dilation “Pruned tree appearance” - progressive fibrosis, the peripheral bile ducts are obliterated Mural irregularities, webs, diverticula, and stones 79

68. 80

69. LIVER PARENCHYMAL CHANGES PSC-induced cirrhosis: Markedly deformed with severe contour lobulations Atrophy of p osterior segment of the right hepatic lobe and the lateral segment of the left lobe . Marked hypertrophy of the caudate lobe. Atrophied right hepatic lobe may be hypodense (due to fibrosis) relative to the hypertrophied caudate lobe, creating the effect of a pseudotumor. 81

70. 82

71. Peripheral wedge-shaped areas of confluent fibrosis with decreased enhancement on contrast-enhanced arterial phase images Peripheral heterogeneous parenchymal enhancement Owing to altered blood supply in response to inflammation between the wedge-shaped areas of confluent fibrosis 83

72. T1W: Randomly distributed areas of high signal intensity (c holestasis and lipofuscin deposits in atrophic liver cells) T2W: Wedge-shaped peripheral atrophic areas of confluent hepatic fibrosis demonstrate high signal intensity Parenchymal edema and hyperperfusion owing to peripheral parenchymal inflammation Impaired lymphatic and venous drainage of the portal triads Periportal edema in PSC could be identified as periportal high signal intensity 84

73. Postcontrast images: T1W (alterations in blood flow in response to regional inflammation) Peripheral wedge-shaped areas of atrophy: Hypoenhancement in early contrast-enhanced phases Hyperenhancement in more delayed contrast-enhanced phases. 85

74. Secondary causes of sclerosing cholangitis 86

75. DIFFERENTIAL DIAGNOSIS CHOLANGIOCARCINOMA: 90% of cases - focal stricture/ polypoid mass 10% of cases- metastatic spread or multicentricity Point favouring CCA : CCA usually obstruct more completely than the fibrous strictures of PSC do. Rapid clinical deterioration ( rapid rise in serum bilirubin concentration and liver function test results) Intraluminal filling defects 1 cm or larger ( PSC usually small 2 -5mm) Mural thickening of the extrahepatic bile ducts of 5 mm or more Periportal soft tissue of 1.5 cm or more Diffuse band strictures and multiple diverticula if present – excludes the diagnosis of CCA.( However seen only in 25% of PSC cases) Dominant stricture – (25% cases of PSC). CCA complicates PSC in 10 -15% cases . 87

76. Primary Biliary Cholangitis Chronic cholestatic syndrome of unknown cause It is characterized by inflammatory destruction of the small bile ducts within the liver. 90% of patients with PBC are females ( Males to females 10 : 1). Ulcerative colitis is not associated with PBC. PBC eventually leads to cirrhosis of the liver and is the third most common indication for liver transplantation in adults. Alterations of cell-based immunity - Sensitized T lymphocytes and possibly B lymphocyte may mediate the duct injury Serum antimitochondrial antibody - highly sensitive for PBC( 85 – 100%) 88

77. Associated autoimmune and collagen-vascular diseases Rheumatoid arthritis Sjögren’s syndrome Hashimoto’s thyroiditis Dermatomyositis Scleroderma CRST syndrome (calcinosis cutis, Raynaud’s phenomenon, sclerodactyly, telangiectasia) Systemic lupus erythematosus. Middle aged female with fatigue & right upper quadrant abdominal discomfort with unexplained itching. Pruritus (often the first symptom) Jaundice & skin hyperpigmentation : 6months – 2yrs Xanthomata and xanthelasma - hypercholesterolemia Clubbing In later stages, - osteomalacia , liver failure, and portal hypertension 89

78. Ultrasound and CT Hepatomegaly Later stages: liver volume decreases with atrophy of the right liver lobe and relative hypertrophy of the caudate and left lobes. Fibrosis: lacelike pattern of thin or thick bands of low attenuation that surround regenerating nodules. Lymphadenopathy is seen in 80% to 90% of patients in porta hepatis and portacaval locations Features pf portal hypertension. 90

79. MRI Cirrhosis and lymphadenopathy. “Periportal halo sign ”: end-stage PBC - When a small (5-mm to 1-cm) rounded lesion of decreased T1 and T2 signal intensity is seen surrounding a portal venous branch. - Lesions are numerous, involve all hepatic segments with no mass effect. 91

80. Differentials: Regenerating nodules: variable in size and signal intensity and may exhibit mass effect. Periportal edema : high signal intensity on T2-weighted images in a periportal distribution. 92 Strictures are the hallmark of PSC by cholangiography. With PBC, the bile duct deformities are less severe and mainly confined to the intrahepatic bile ducts. The diverticular outpouchings and mural irregularities that are classic in PSC are not seen with PBC.

81. PSC PBC Clinical features Male > female( 2: 1) Young age( 20 - 30) Progressive cholestatic jaundice Cholestatic lab values Female >Males Middle age(30 – 40) Fatigue and pruritis Cholestatic lab values Site of involvement Intra and extrahepatic bile ducts Intrahepatic bile ducts only Cause of obstruction Fibrosis Granulomatous inflammation Associations Ulcerative colitis Autoimmune disorders Diagnostic clue Beaded appearance Peripheral wedge shaped areas of decreased enhancement Periportal halo sign Long term complications Cirrhosis Cholangiocarcinoma( 10 -15%) Cirrhosis 93

82. NEOPLASTIC BILIARY PATHOLOGIES BILIARY CYSTADENOMA CHOLANGIOCARCINOMA PRIMARY GB CARCINOMA IPMN-B METASTASIS AND LYMPHOMA PANCREATIC AND ANPULLARY TUMORS

83. BILIARY CYSTADENOMA Benign cystic neoplasm occurring predominantly in middle aged women Non specific symptoms- pain, nausea, vomiting ,obstructive jaundice. Do not communicate with biliary system. Imaging features: -large multi loculated , cystic mass. Presence of septations distinguishes cystadenoma from a simple cyst. The septations may mimic an echinococcal cyst. In contrast to hepatic abscess or necrotic metastasis , a thick enhancing wall is not a feature of cystadenoma. The presence of frank invasion into adjacent liver, a large solid component or thick calcification should raise concern for cysadenocarcinoma .

84. CHOLANGIOCARCINOMA : adenocarcinoma of the bile ducts. Arises from epithelial lining of bile ducts, peribiliary glands, progenitor cells, or hepatocytes- possibly secondary to chronic inflammation and bile stasis. Types: Intrahepatic: Subtypes: Small duct ( nonmucin -producing cuboidal cells). Large duct (mucin-producing cells). perihilar (most common), and distal. Growth Patterns: Mass-forming: Common in small duct intrahepatic type; presents as a fibrous mass with necrosis. Periductal Infiltrating: Common in large duct intrahepatic, perihilar, and distal types; manifests as strictures and ductal wall thickening. Intraductal: Often malignant transformations of IPNB; common in perihilar and distal types.

85. Imaging features: Intrahepatic CC Manifest as discrete parenchymal masses. Show variable degrees of fibrosis, necrosis, and heterogeneity. On MRI: Lower T1 and variable T2 signal intensity compared to background liver with early peripheral enhancement with progressive or delayed enhancement due to fibrous stroma. Central T2 hypointensity indicates central fibrosis. Structural Effects: Fibrous stroma causes capsular retraction in peripheral lesions. Upstream biliary dilatation may be observed. Differential Diagnosis: if shows arterial enhancement and delayed washout can mimic hepatocellular carcinoma and combined hepatocellular carcinoma-cholangiocarcinoma.

86. PERIHILAR AND DISTAL CHOLANGIOCARCINOMAS: Biliary stricture and upstream dilatation are hallmark features Imaging Techniques: MRI or MRCP is preferred for staging; some institutions use CT. MRI and MRCP should be done before ERCP to avoid confounding postprocedural ductal inflammation. Diagnosis and Staging: ERCP is used for tissue sampling and stenting to relieve obstruction .

87. Attention is required for hilar vascular involvement as it affects tumor resectability . Signs and Features: Associated periductal mass may be seen depending on the stage. Severe narrowing or occlusion of a major portal vein branch can lead to atrophy of the supplied liver lobe and compensatory hypertrophy of the unaffected lobe, known as the "atrophy-hypertrophy" sign. Advanced Imaging: PET/CT is useful for evaluating nodal and distant metastases.

88. PRIMARY GB CARCINOMA Rare malignancy with a poor prognosis Typical clinical presentation- right upper quadrant pain, weight loss, jaundice Risk factor- gallstones, chr. cholecystitis., porcelain gb , PSC ,IBD , adenomatous polyp > 10mm Imaging features : Focal/diffuse irregular gb wall thickening or Large gb fossa mass with little/no identifiable lumen– gb stones may appear ‘ buried’ in the mass Doppler blood flow within the mass, and contrast enhancement on CT/MRI

89. MALIGNANT LESIONS:- Cancer spread- nodal spread(early)- around the portal vein and extending down to the head of pancreas Invade the adjacent liver( segments 4 & 5) Gallbladder wall destruction

90. IPNB: a rare biliary neoplasm, a precursor for cholangiocarcinoma. Geographic Risk Factors: In Asia: Major risk factors are Clonorchis infection and hepatolithiasis. In Western countries: Primary sclerosing cholangitis (PSC) and choledochal cysts are more common. Mucin production is less common in IPNBs (33%) compared to intraductal papillary mucinous neoplasms (100%).

91. Type 1 IPNB : Type 2 IPNB : arises in intrahepatic ducts. arises in extrahepatic ducts. Commonly shows mucin production. Infrequently produces substantial mucin. both low- and high-grade dysplasia. shows high-grade dysplasia. Invasion in 50% cases Invasion in 90% cases

92. Ultrasound (US) Imaging: Intraductal filling defects, representing a mass, can be seen in up to 41% of cases. The mucinous component is anechoic, similar to bile, and undetectable. Contrast-enhanced US may help distinguish a solid mass from sludge or stones. Magnetic Resonance Imaging (MRI) : Often shows biliary dilatation due to solid intraluminal papillary lesions or thick, viscous mucin. Solid component : hypointense on T1-weighted images and shows intermediate signal intensity on T2-weighted images. Mucinous component: indistinguishable from bile or show string-like filling defects on MRCP images (the "thread sign"). Intraluminal papillary filling defects with arterial enhancement, early washout, and associated biliary ductal dilatation

93. Variability in solid component extent and mucin production leads to diverse imaging appearances: Solid biliary mass with upstream biliary dilatation. Focal (sometimes cystic) duct dilatation from mucin production without a visible mass. Imaging Mimics of IPNB: Obstructing Lesions Causes of Focal Biliary Dilatation Hepatolithiasis. Choledochal cysts. Cholangiocarcinoma. Hepatic mucinous cystic neoplasms.

94. Pancreatic and ampullary tumors On cholangiography , pancreatic carcinoma produces a tight stricture that is often shouldered, but may have a blunt cut-off that is straight or convex upward or downward. Adjacent strictures of both bile duct and pancreatic duct ( ‘double duct sign’) are highly s/o pancreatic ca or less often ,periampullary ca. Dd- cholangiocarcinoma, mets , amp & periamp ca.

95. References Gore & Levine – Textbook of Gastrointestinal Radiology – Fourth edition. Imaging Features of Primary Sclerosing Cholangitis: From Diagnosis to Liver Transplant Follow-up- Pegah Khoshpouri et al. 113

96. THANK YOU 114