Imaging approach to Pancreas, Gallbladder and Bile duct anomalies and anatomical variants A Reinders Department of Radiology March 2012 Introduction • Embryology & normal anatomy – Pancreas – Bile ducts – Gallbladder – Cystic duct – Liver vascular anatomy* • Congenital variants • Imaging approach • Report Embryology Bile duct 4th Week of Fetal life Hepatic ducts Hepatic Diverticulum Gallbladder Dorsal pancreatic Outpoutching Ventral pancreatic outpoutching Primitive Foregut & midgut Figure 1a. Drawings illustrate the normal embryologic development of the pancreas and biliary tree. Mortelé K J et al. Radiographics 2006;26:715-731 ©2006 by Radiological Society of North America Embryology 7th Week of Fetal life Dorsal pancreas Dorsal pancreatic outpoutching Posterior pancreatic ductal system Pancreas Extrahepatic BD Ventral pancreatic outpouching Intrahepatic BD Ventral pancreas Figure 1c. Drawings illustrate the normal embryologic development of the pancreas and biliary tree. Mortelé K J et al. Radiographics 2006;26:715-731 ©2006 by Radiological Society of North America Figure 1d. Drawings illustrate the normal embryologic development of the pancreas and biliary tree. Mortelé K J et al. Radiographics 2006;26:715-731 ©2006 by Radiological Society of North America Congenital Variants • Pancreas – Annular pancreas – Hypoplasia/aplasia of the pancreas – Ducts • Rudimentary duct of Santorini • Dominant duct of Santorini • Ansa Pancreatica – Pancreas Divisum – Ectopic pancreas Annular Pancreas • Rare = 1:2000 – Incomplete rotation of ventral anlage • Segment of pancreas encircling 2nd part of duodenum – Obstruction 10% Extramural Intramural Ventral pancreatic duct Pancreatic tissue intermingled with muscle fibres Encircles duodenum and joins MPD Small ducts drains directly into duodenum Lecco’s theory Baldwin’s theory Lee NK, Kim S, Jeon TY et al. Complications of congenital and developmental abnormalities of the gastrointestinal tract in adolescents and adults: Evaluation with multimodality imaging. Radiographics 2010;30:1489-1507 Annular Pancreas Annular pancreas in a 55-year-old man with repeated episodes of vomiting. Contrast-enhanced CT image shows pancreatic tissue (arrows) completely encircling the descending portion of the duodenum (*). Lee NK, Kim S, Jeon TY et al. Complications of congenital and developmental abnormalities of the gastrointestinal tract in adolescents and adults: Evaluation with multimodality imaging. Radiographics 2010;30:1489-1507 Annular Pancreas Mortele KJ, Rocha TC, Streeter JL et al. Multimodality Imaging of Pancreatic and Biliary Congenital Anomalies. Radiographics 2006; 26:715-731 Hypoplasia/Agenesis of Pancreas • Hypoplasia – Absence of ventral/dorsal anlage – Dorsal hypoplasia more common • NB to rule out pancreatic carcinoma with “upstream” atrophy of gland • Degrees of hypoplasia with varying degrees of abscence of neck, body and tail, MDP and duct of Santorini • Agenesis – Total agenesis is rare = incompatible with life – Associated with other GIT malformations • Polysplenia • GB aplasia Ductal Anatomy • Two major duct – Wirschung • Main = 1.5 – 3.5 mm diameter • 20 – 30 side branches • Meets with CBD to pass through SOO8 – Y (75%) or V (20%) configuration – 10 – 15 mm long – U type (5%) – Santorini • Drains anterior and superior portion of head • Normal narrowing at level of junction between MPD and W • No proximal dilatation of duct – Minor duodenal papilla • +/- 27 different ductal configurations Figure 3a. Normal pancreatic ductal anatomy. Mortelé K J et al. Radiographics 2006;26:715-731 ©2006 by Radiological Society of North America Ductal variants • Rudimentary duct of Santorini (30%) – Duct of Wirsung as manor drainage route still • Dominant duct of Santorini (1%) – Major drainage route • Ansa Pancreatica – Duct of Santorini forms a sigmoid curve as it courses to duct of Wirschung Figure 6b. Variant pancreatic ductal anatomy – Ansa Pancreatica Mortelé K J et al. Radiographics 2006;26:715-731 ©2006 by Radiological Society of North America Sphincter of Oddi • 3 separate smooth muscle layers – Surrounds MPD and CBD before AOV • Anomalous junctions – Fusion of MPD and CBD outside duodenal wall – = Long common channel (>15mm) • Reflux – Pancreatitis – Cholangitis • Cyst • Choledocal web Figure 3d. Normal pancreatic ductal anatomy. Mortelé K J et al. Radiographics 2006;26:715-731 ©2006 by Radiological Society of North America Figure 10a. Abnormal common channel. Mortelé K J et al. Radiographics 2006;26:715-731 ©2006 by Radiological Society of North America Figure 10b. ERCP: Abnormal common channel with CBD web in child Mortelé K J et al. Radiographics 2006;26:715-731 ©2006 by Radiological Society of North America Pancreas Divisum • Common 4 – 10% • Ventral and dorsal ducts DONT fuse – Wirschung (ventral) = atretic & short – Santorini (dorsal) = Larger in caliber • Focal dilatation of terminal portion – Santorinicele • Cause obstruction at minor papillae of duodenum Figure 6a. Variant pancreatic ductal anatomy - Santorinicele Mortelé K J et al. Radiographics 2006;26:715-731 ©2006 by Radiological Society of North America Mortele KJ, Rocha TC, Streeter JL et al. Multimodality Imaging of Pancreatic and Biliary Congenital Anomalies. Radiographics 2006; 26:715-731 Ectopic pancreas • Incidence – 0,6 – 13% • 0,5 – 2 cm in largest dimensions • Usually asx – rarely become malignant • In submucosa (50%) – Stomach (26 - 38%) – Duodenum (28 – 36%) – Jejenum (16%) – Meckel’s diverticulum Biliary System • Liver segments – Cuinaud classification • Main hepatic ducts • Cystic duct • Choledochal cyst – Todani’s classification • Gallbladder Biliary System • Intrahepatic bile ducts (IBD) run parallel to portal supply • RHD – Right posterior duct = I, VI & VII (horizontal)7 • Super and Inferior – Right anterior duct = V & VIII (vertical) • Superior and inferior • LHD – Draining II, III and IV • Lateral and medial – Superior and inferior • CHD • 58 % of people Images available from URL: http://www.pkdiet.com/pages/pld/pldresection.htm Figure 5. Normal biliary anatomy. Mortelé K J et al. Radiographics 2006;26:715-731 ©2006 by Radiological Society of North America Biliary System • Right posterior duct (RHD) – Drain into LHD before confluence with RAD • 13 – 19% – Will not pass RAD posterior but drains directly into it • 12% – “Tripple confluence” • 11% – Drains into CHD • Left <1% • Right 5% - “aberrant hepatic duct” Biliary System Onofrio AC, Anandkumar HS, Raul NU et al. Vascular and biliary variants in the liver: Implications for liver surgery. Radiographics 2008; 28:359-378 Biliary System Cystic duct • Low insertion – Into distal 1/3 of CHD (9%) • Medial insertion – Left side of CHD (10-17%) • Parallel coarse with CHD – 1.5 – 25% – 2 cm long • Spiral course – Anterior – Posterior • Into intrahepatic bile duct – Right (0.3%) and left rarely • Abscence – Drains directly into CBD Figure 6. Anatomic variants in the cystic duct. Turner M A , Fulcher A S Radiographics 2001;21:3-22 ©2001 by Radiological Society of North America Figure 7b. (7a) Cholangiogram shows a right lateral insertion of the cystic duct (arrows) into the extrahepatic bile duct. Turner M A , Fulcher A S Radiographics 2001;21:3-22 ©2001 by Radiological Society of North America Biliary System • Choledochal cysts – Rare – Biliary tree dilatation – > Female 4:1 • • • • Abdominal pain Jaundice Right upper quadrant mass Children 2 – 38% Todani Classification Images available from URL: http://radiopaedia.org/encyclopaedia/quizzes/all/8097 Figure 16b. Todani Type 1 Choledochal cysts. Mortelé K J et al. Radiographics 2006;26:715-731 ©2006 by Radiological Society of North America Figure 16d. Todani Type 2 Choledochal cysts. Mortelé K J et al. Radiographics 2006;26:715-731 ©2006 by Radiological Society of North America Figure 16f. Todani Type 3 Choledochal cyst Mortelé K J et al. Radiographics 2006;26:715-731 ©2006 by Radiological Society of North America Figure 17b. (a, b) Drawing (a) and coronal MR cholangiopancreatogram (b) show type IV choledochal cysts. Mortelé K J et al. Radiographics 2006;26:715-731 ©2006 by Radiological Society of North America Figure 17d. (a, b) Drawing (a) and Endoscopic Retrograde Cholangiopancreatogram (b) show type IV choledochal cysts. Mortelé K J et al. Radiographics 2006;26:715-731 ©2006 by Radiological Society of North America Caroli’s Disease • Imaging – “Central dot sign” • Dilagted IHD with contrast enhancement of the portal branches • Todani classifications Type 5 – If large IBD affected = Caroli’s disease – If small interlobular bile ducts also affected = Congenital hepatic fibrosis • Caroli’s Syndrome Gallbladder • Adjacent to inferior surface of liver – Plane of interlobar fissure – Different positions • Under left lobe – Situs inversus • Intrahepatic – Subcapsular along ant-inf surface of right lobe of liver • Transverse • Retroperitoneal – Congenital – Acquired Gallbladder • GB displacement/rotation – Hepatic lobe abnormalities • Aplasia • Hypoplasia – Associated with Cystic Fibrosis • Hypertrophy • Agenesis • Duplication Rare Gallbladder • Phrygian cap – Ancient Greek headgear – Asx folding of GB fundus • Junctional fold – Usually posterior wall • Septa – Multiseptate • Honeycombed appearance Statis and stone formation – Extension of Spiral valves of Heister • Other – Duplication/Triplication, Bifid gallbladder – Diverticulum Gallbladder Meilstrup JW. Hopper KD. Thieme GA. Imaging of gallbladder variants. AJR 1991;157:1205-1208 Meilstrup JW. Hopper KD. Thieme GA. Imaging of gallbladder variants. AJR 1991;157:1205-1208 Liver • Arterial – Proper hepatic artery (CHA from Coeliac trunk) • Right, middel and left hepatic artery (55%) • Porto-venous – Porta hepatis (SMV and SV) • Right – Post and anterior • Left portal vein • Venous = IVC – Right • Segment 6 & 7 – Middle • Segments 4,5 & 8 – Left • Segments 2 & 3 Common trunk (60%) Arterial and Venous anatomy Onofrio AC, Anandkumar HS, Raul NU et al. Vascular and biliary variants in the liver: Implications for liver surgery. Radiographics 2008; 28:359-378 Porto-venous anatomy Onofrio AC, Anandkumar HS, Raul NU et al. Vascular and biliary variants in the liver: Implications for liver surgery. Radiographics 2008; 28:359-378 Arterial Variants Onofrio AC, Anandkumar HS, Raul NU et al. Vascular and biliary variants in the liver: Implications for liver surgery. Radiographics 2008; 28:359-378 Arterial Variants Onofrio AC, Anandkumar HS, Raul NU et al. Vascular and biliary variants in the liver: Implications for liver surgery. Radiographics 2008; 28:359-378 Venous Variants • Tributary veins – Drain segments in addition to hepatic veins • Eg. Segment 8 into MHV (9%) • NB for surgical incision (Cantlie line) • Accessory inferior right hepatic vein – Drains directly into IVC (47%) – NB: • Nr of acc veins • Size and distance from main hepatic venous drainage site along IVC – Surgical difficulty if >40 mm Venous Variant Onofrio AC, Anandkumar HS, Raul NU et al. Vascular and biliary variants in the liver: Implications for liver surgery. Radiographics 2008; 28:359-378 Portal Vein Variants Gallego C. Velasco M. Marcuello P et al. Congenital and Acquired anomalies of the portal venous system. Radiographics 2002;22:141-159 Portal Vein Variants • Variants common (20%) – Trifurcation (7 – 10%) – RPPV from MPV (5 – 6%) – RAPV from LPV (3 – 4%) • Cantlie line • Hypovascular surgical line – transplantations • 1cm to right of MHV – Between IVC and gallbladder fossa Imaging • No surprises – Radiologist/Surgeon • Pre operative planning – – – – Liver transplant/resection/cholecystectomy Whipple’s procedures Intra arterial chemotherapy (HAIP) Asymptomatic • Several options – Helical CT Cholangiography, MR Cholangiography – ERCP, PC Cholangiography – Oral Cholangiography, Scintigraphy • Best? – Kapoor V, Peterson MS, Baron RL. Intrahepatic biliary anatomy of living adult donors: Correlation of Mangafodipir Trisodium – enhanced MR Cholangiography and intraoperative cholangiography. AJR Nov 2002; 179(5):1281-1286 Report • Technique used – Sequences and contrast material – Puncture site • Normal anatomy – If not – where does what implant? • Classifications and measurements • Distinguish from pathological processes Bibliography • • • • • • • • • • • 1. Lee NK, Kim S, Jeon TY et al. Complications of congenital and developmental abnormalities of the gastrointestinal tract in adolescents and adults: Evaluation with multimodality imaging. Radiographics 2010;30:1489-1507 2. Mortele KJ, Rocha TC, Streeter JL et al. Multimodality Imaging of Pancreatic and Biliary Congenital Anomalies. Radiographics 2006; 26:715-731 3. Rizzo RJ, Szucs RA, Turner MA. Congenital abnormalities of the pancreas and biliary tree in adults. Radiographics 1995;15:49-68 4. Onofrio AC, Anandkumar HS, Raul NU et al. Vascular and biliary variants in the liver: Implications for liver surgery. Radiographics 2008; 28:359-378 5. Turner MA, Fulcher AS. The Cystic Duct: Normal Anatomy and Disease Processes. Radiographics 2001;21:3-22 6. Kapoor V, Peterson MS, Baron RL. Intrahepatic biliary anatomy of living adult donors: Correlation of Mangafodipir Trisodium – enhanced MR Cholangiography and intraoperative cholangiography. AJR Nov 2002; 179(5):1281-1286 7. Applied Radiological anatomy. Butler P, Mitchell AWM, Ellis H Editors. Cambridge University Press. United Kingdom. 2008. Chapter 9. Embryology of the gastrointestinal tract and its adenxae. p185-186 8. Radiology Review Manual. 6th Edition. Danhert Wolfgang. Lippincott Williams & Wilkins. Philadelphia. 2007. p687 - 690 9. Primer of Diagnostic Imaging. 4th Edtion. Weissleder R, Wittenberg J, Mukesh GH, Chen J. Mosby Elsevier. 2007. p227-228 10. Meilstrup JW. Hopper KD. Thieme GA. Imaging of gallbladder variants. AJR 1991;157:1205-1208 11. Gallego C. Velasco M. Marcuello P et al. Congenital and Acquired anomalies of the portal venous system. Radiographics 2002;22:141-159