Pancreas Anatomy 2023 - PDF

8/1/23 Pancreas Anatomy Chapter 12 1 Objectives Embryology Location Anatomy Physiology Variants Sonographic appearance 2  Forms from the primitive foregut Ventral pancreatic bud rotates around EMBRYOL duodenal axis towa...

8/1/23 Pancreas Anatomy Chapter 12 1 Objectives Embryology Location Anatomy Physiology Variants Sonographic appearance 2  Forms from the primitive foregut Ventral pancreatic bud rotates around EMBRYOL duodenal axis toward dorsal bud to form OGY head Dorsal pancreatic bud fuses with ventral bud 3  Two ducts form in most cases – main duct Wirsung and accessory PANCREATI Santorini C DUCTS Both drain into the duodenum at separate sites 4 Pancreas Assisting in digestion and metabolic processes Dual function organ – endocrine and exocrine functions Two types of cells – Isles of Langerhans and Acini cells 5  Location Orientation Epigastrium and left hypochondrium Non encapsulated Retroperitoneal Horizontal orientation Lies between duodenal loop and splenic hilum Closely placed to stomach, transverse colon, duodenum Stomach is anterior to the pancreas, the left kidney is posterior 6 Posterior to pancreas Peri-vertebral connective tissue IVC and Aorta Left kidney Diaphragm 7 Segments of the Pancreas Size Segments of the pancreas head, neck, body, tail, and uncinate process (medial extension of the head) Length of the pancreas 12 to 18 cm The gland weights 60 to 80 gr Measurements HEAD – 2 to 3 CM NECK – 1.5 to 2.5 CM BODY – 2 to 2.5 CM TAIL – 1 to 2 CM Smooth, well-defined contour without focal 8 enlargements  The pancreas is closely related to the biliary tree and portal venous system CBD travels inferior and medially from Porta hepatis Runs posterior to the pancreatic head or within Joins main pancreatic duct at Ampulla of Vater to be drained into the second portion of the duodenum 9 Pancreas is closely related to the portal venous system Splenic vein runs posterior to the pancreas Joins SMV to form portal confluence posterior to the neck of the pancreas IVC located posterior to the head of the Pancreas 10  Sonographic Appearance Pancreas is closely related to the portal venous system Splenic vein runs posterior to the pancreas Joins SMV to form portal confluence posterior to the neck of the pancreas IVC located posterior to the head of the Pancreas 11 Describe the location of the pancreas with respect to a body region with respect to relational anatomy Name the segments of the pancreas Functions of the pancreas The average size of the pancreatic segments _____ Major vascular landmarks Pancreas and relation to the biliary tree Describe the contour of the 12 gland  Gross and GDA Sonographic Anatomy CBD Head Is oriented medially and inferiorly to the rest of the gland Anterior to IVC Two vessels are seen in the head CBD and GDA GDA – anterolateral aspect CBD – posterolateral aspect Uncinate process is a posteromedial extension of the head Uncinate process lies posterior to SMV Ampulla of Vater location Main duct and CBD junction Accessory duct drains 2 cm superiorly 13 Uncinate Uncinate process is a posteromedial process- extension of the head common Uncinate process lies anterior to IVC and posterior to SMV variant 14  Gross and Sonographic Anatomy Neck Narrowest portion of the pancreas Located anterior to SMV or Portal confluence Body Largest segment of the pancreas Outlined by Splenic vein posteriorly Splenic artery runs along the anterior aspect of the pancreatic body and tail Tail Most lateral portion of the pancreas Ends at the splenic hilum Splenic artery runs along 15 anterior aspect and  Duct of Wirsung Duct of Santorini Pancreati Primary duct, extending the entire length of the gland Secondary duct that drains the upper anterior head c Ducts Enters the medial second part of the duodenum with the common bile duct at the ampulla of Vater (guarded by the sphincter of Oddi) Measure less than 2mm 16  Vascula r Supply Celiac artery is the main artery GDA is the first branch of the CHA GDA runs along the anterolateral aspect of the pancreatic head GDA branches into smaller arteries to supply HEAD SPLENIC artery supplies the rest of the organ via multiple branches Venous drainage is done via Splenic vein and SMV 17  Physiology Dual function organ Exocrine gland when assisting with digestion by releasing digesting enzymes Endocrine gland, when releasing hormones for metabolic needs Pancreas mostly consists of exocrine tissue, 98% of the gland weight 18  Physiology Exocrine Function of Pancreas Endocrine Function of the Exocrine function is carried out Pancreas by Acini cells Endocrine function is carried Acini cells are producing out by Isles of Langerhans pancreatic enzymes of the Groups of cells – Alpha, Betta, pancreatic juice and Delta 2 liters of pancreatic juice per day Sodium Neutralizes stomach acid Betta Conversion of glucose into Bicarbonate cells glycogen (largest produce component of insulin pancr. juice) Alpha Conversion of glycogen into Amylase Digestion of cells glucose carbohydrates produce glucagon Lipase Digestion of fats Delta Inhibitors for Alpha and Betta Trypsin Digestion of proteins cells cells Nucleases Digestion of nucleic When fats and amino acids are ingested, the duodenal mucosa releases the acids cholecystokinin (CCK) peptide hormone of the gastrointestinal system. CCK relaxes the Sphincter of Oddi. The gallbladder and pancreas release digestive juices and bile into the duodenum. 19  Congenital Anomalies and Variants Pancreas Divisum : When the dorsal and ventral pancreatic ductal system fails to fuse properly during embryonic development, it can lead to a smaller Santorini duct that drains only part of the pancreas. Inadequate pancreatic enzyme drainage may result in pancreatitis. Annular pancreas: This is a rare birth defect in which a ring of healthy pancreatic tissue surrounds the duodenum due to the abnormal migration of the ventral pancreas. 20 Variations in the lie/shape of the pancreas include transverse, horseshoe, sigmoid, L-shaped, and inverted V. 21  Sonographic Appearance The echogenicity depends on the amount of fat between the lobules. Compared to the liver, the pancreas is slightly hyperechoic in adult patients And isoechoic/hypoechoic in Pediatric pancreas pediatric Children have less echo-dense Echogenicity of the pancreas than pancreas adults. increases with age due to fat deposition or fibrosis Size decreases with age Echogenicity in the order of least to Adult pancreas most: Children < Adults < Older (about 60 22 y.o.)  Indications for sonographic evaluation Uses of pancreatic sonography include the following: Associate distal biliary tree measurements Identification of pancreatic masses Identification of epigastric masses Main pancreatic duct measurements Adjacent associated biliary masses Associated biliary obstruction Diagnosis and follow-up evaluation of acute and chronic pancreatitis Diagnosis and follow-up evaluation of pancreatic pseudocysts Endoscopic pancreatic ultrasound for identification of pancreatic lesions on patients whose CT results were inconclusive 23  Transverse scanning plane – longitudinal pancreas Transverse scanning plane images of the mid-epigastrium showing longitudinal sections of the pancreas gland. Note the appearance and proximity of surrounding structures. The anechoic, short sections of the common bile duct (posteriorly) and gastroduodenal artery (anteriorly) along the right lateral margin of the pancreatic head are easily visualized 24  Transverse scanning plane – longitudinal pancreas Transverse scanning plane images of the mid-epigastrium showing longitudinal sections of the pancreas gland. The anechoic, axial sections of the common bile duct (posteriorly) and gastroduodenal artery (anteriorly) along the right lateral margin of the pancreatic head are easily identified in these images 25  Transverse scanning plane – longitudinal pancreas Transverse scanning plane images of the mid-epigastrium showing longitudinal sections of the pancreas gland. Note the appearance and proximity of surrounding structures. The anechoic, axial sections of the common bile duct (posteriorly) and gastroduodenal artery (anteriorly) along the right lateral margin of the pancreatic head are easily identified in these images 26  Transverse scanning plane – longitudinal pancreas Transverse scanning plane images of the mid-epigastrium showing longitudinal sections of the pancreas gland. Note the appearance and proximity of surrounding structures. The anechoic, ellipsoid in shape portal confluence is the landmark for pancreatic neck 27  Transverse scanning plane – longitudinal pancreas Transverse scanning plane images of the mid-epigastrium. Longitudinal sections of the pancreas body Notice how the body lies anterior to, and in the same plane with, the aorta and superior mesenteric artery, medial to the neck and tail, and posterior to the stomach and liver. A and C clearly demonstrate how the splenic vein runs along the posterior surface of the body 28  Transverse scanning plane – longitudinal pancreas Transverse scanning plane images of the mid-epigastrium. Longitudinal sections of the pancreas body Notice how the body lies anterior to, and in the same plane with, the aorta and superior mesenteric artery, medial to the neck and tail, and posterior to the stomach and liver. Splenic vein runs along the posterior surface of the body 29  Transverse scanning plane – longitudinal pancreas Transverse scanning plane images of the mid-epigastrium. Longitudinal sections of the pancreas body Notice how the body lies anterior to, and in the same plane with, the aorta and superior mesenteric artery, medial to the neck and tail, and posterior to the stomach and liver. A and C clearly demonstrate how the splenic vein runs along the 30 posterior surface of the body  Transverse scanning plane – longitudinal pancreas In this transverse scanning plane image of the mid–epigastrium, it is easy to appreciate the anechoic longitudinal section of the splenic vein following along the curvilinear shape of the posterior surface of the pancreas body and tail. 31  Transverse scanning plane – longitudinal pancreas Mid-epigastric transverse scanning plane image showing how the splenic vein hugs the posterior surface of the tail and body along its course to the confluence 32  Sagittal scanning plane – short sections of pancreas IVC PANCREAS HEAD SAG Sagittal scanning plane images just to the right of the midline, show axial sections of the pancreas head and portal vein (PV) IVC anterior to a longitudinal section of the inferior vena cava (IVC) PANCREAS HEAD TRV 33  Sagittal scanning plane – short sections of pancreas PANCREAS HEAD SAG Sagittal scanning plane image just to the right of the midline shows axial sections of the pancreas head and portal vein (PV) anterior to a longitudinal section of the inferior vena cava (IVC). Note the small, anechoic, axial section of the right renal artery posterior to the IVC. Small, anechoic, longitudinal structure in the PANCREAS HEAD 34 TRV posterior portion of the pancreas head is the common  Sagittal scanning plane – short sections of pancreas PANCREAS NECK SAG Sagittal scanning plane image just medial to the level of the head of the pancreas. Note the axial sections of the pancreas neck and uncinate process separated by the anechoic, longitudinal section of the superior mesenteric vein. Note how the uncinate process sits directly anterior to, or in front of, the inferior vena cava. The level where the pancreas neck is anterior to the PANCREAS NECK superior mesenteric vein and the uncinate process is TRV a level slightly inferior to the portal splenic 35  Sagittal scanning plane – short sections of pancreas PANCREAS NECK SAG Sagittal scanning plane image of the abdomen at the level of the neck of the pancreas. Note the axial section of the mid-gray neck located immediately anterior to the anechoic long section of the superior mesenteric vein. PANCREAS NECK TRV No uncinate process 36  Sagittal scanning plane – short sections of pancreas Celiac Axis Pancreas body sag Sagittal scanning plane image of the abdomen just to the left of the midline, showing an axial section of the body of the pancreas inferior to the anechoic long section of the celiac axis/splenic artery, immediately anterior to the anechoic axial section of the splenic vein, anterior to the anechoic long sections of the superior mesenteric Pancreas body Pancreas body trv artery and aorta, and posterior to portions of the trv 37  Sagittal scanning plane – short sections of pancreas Sagittal scanning plane image of the abdomen just to the left of the midline, showing another axial section of the body of the pancreas inferior to the anechoic long section of the celiac axis/splenic artery, immediately anterior to the anechoic axial section of the splenic vein, anterior to the anechoic long sections of the superior mesenteric artery and aorta, and posterior to a portion of the liver 38  Sagittal scanning plane – short sections of pancreas Sagittal scanning plane image of the abdomen slightly left lateral to the aorta. An axial section of the tail of the pancreas is noted between the liver (anteriorly) and the left kidney (posteriorly). Note the portion of bowel anteroinferior to the tail and the axial section of the anechoic splenic vein along the tail’s posterior margin 39  Sagittal scanning plane – short sections of pancreas Sagittal scanning plane image of the abdomen, just to the left of the midline, showing an axial section of the pancreas tail situated between a long section of the left lobe of the liver (anterosuperiorly) and long section of the left kidney (posteriorly). Note the anechoic axial section of the splenic vein between the tail and left kidney. 40 Transverse scanning plane image of the mid-epigastrium, demonstrating an enlarged tail of the pancreas. This patient has a congenital malformation in which the tail is partially duplicated. Note the proximity of the tail and left kidney 41 Normal Pancreatic Parenchymal Echogenicity. Transverse sonograms in 12 normal patients demonstrate the various patterns of normal pancreatic parenchyma. Echogenicity, texture, and size vary considerably.42LK, Left kidney. Common Laboratory tests Serum tests: Amylase: 60-80 units Lipase: 1.5 U/mL Glucose (fasting): 65-110 mg/dL (all sugars): 80-120 mg/dL Urine tests: Amylase (2 hr): 35-260 units/hr Alkaline phosphatase: 3.5 U/8 hr 43