4/9/2018 OBJECTIVES PANCREAOTO BILIARY ULTRASOUND: BEYOND CHOLECYSTITIS

Transcription

1 PANCREAOTO BILIARY ULTRASOUND: BEYOND CHOLECYSTITIS Jean Yves Sewah Kaiser Permanente West Los Angeles 1 OBJECTIVES Discuss the role of ultrasound in the evaluation of the gallbladder, biliary tree and pancreas. Review pancreaticobiliary anatomy with an emphasis on normal sonographic appearances. Identify pancreaticobiliary pathology on ultrasound with clinical and CT/MRI correlation. 2 ROLE OF ULTRASOUND IN EVALUATING THE GALLBLADDER AND PANCREATOBILIARY SYSTEM Useful initial modality for suspected gallbladder diseases, biliary tree obstruction and pancreatic lesions. Readily available, less expensive, safe, no radiation exposure. US Gold standard for gallbladder, ERCP best for biliary tract. CT gold standard for pancreas Limitations Pancreas is a retroperitoneal structure, deep intra-abdominal organ, Limited US beam penetration in large body habitus patients / obese. Technically difficult and limited due to overlying bowel gas. Operator dependent 3 1

2 NORMAL GALLBLADDER ANATOMY Pear shaped, musculomembranous sac, located in a fossa underneath the surface of the right lobe of the liver Functions : reservoir, store and concentrate bile Variable in shape and volume, normal capacity is of ml Typically measures 7-10 cm in length and 2.5 cm in width GB wall should measure less than 3 mm. Cystic duct connects the gallbladder to the bile duct Apposed to the liver surface by parietal peritoneum 4 Function of the gallbladder Bile is produced in the liver and stored in the GB until needed Aids in digestion of fats Concentrates bile Cholecystokinin (CCK) Digestive hormone secreted by the small intestine Secreted once fatty foods enter the small intestine Promotes Gb contraction and then release of bile. 5 Divided into the fundus, body and neck 6 2

3 NORMAL VARIANTS Phrygian Cap Most common congenital anatomic variant of the GB Folding of the fundus back upon the GB body Asymptomatic 7 Hartman Pouch Focal dilatation of the GB neck May be pathological, related to cholelithiasis 8 GB Folds Fold between neck and body May have multiple folds 9 3

4 BILIARY TREE ANATOMY Small branching interlobar bile ducts until the major left and right hepatic ducts are formed The right and left hepatic ducts emerge from the liver and unite to form the 3-4 cm long CHD, which then joins the cystic duct to form the CBD Travel with branches of PV and HA in portal triad (mickey mouse) 10 COMMON HEPATIC DUCT Common Hepatic Duct (CHD) Formed by the union of the right and left intrahepatic ducts Union is usually just outside the liver but may be lower, resulting in a shorter CHD or CBD 1-4 cm in length Lies anterior to PV and to the right of the HA Joined at an acute angle by the cystic duct to form the CBD CHD 11 CYSTIC DUCT Cystic Duct Usually measures 2-4 cm in length May have variations of its point of union with the CHD Attaches the GB to the extrahepatic bile duct Its point of insertion into the extrahepatic bile duct marks the division between the common hepatic duct and the CBD Typically displays a tortuous or serpentine course Normal diameter ranges from 1-5 mm,, most often not seen on US. 12 4

5 Common Bile Duct (CBD) Approx cm long Travels initially in the free edge of the lesser omentum, then courses posteriorly to the duodenum and pancreas to unite with the main pancreatic duct to form the ampulla of Vater. Drains at the descending segment of the duodenum. 13 In the majority of patients, the CBD courses through the pancreatic head. Normal intraluminal measurement should be 6 mm (Refer to your department protocol). Measurement is captured from inner wall to inner wall. Proximal measurement is at the porta hepatis Distal measurement is at head of pancreas 1 mm is added to measurement for each decade of life after age 50 Normal to see increased measurements in post cholecystectomy patients 14 Portal Triad Mickey Mouse sign in transverse scan of the portal vein, CBD/CHD and HA Right ear represents CBD/CHD, left ear represents HA 15 5

6 PANCREAS ANATOMY 16 Anatomy Non encapsulated exocrine and endocrine gland measures cm long Normal appearance/ texture is homogeneous. Lies obliquely in a transverse plane in the retroperitoneum, with the head caudal to body & tail Lies in anterior pararenal space Draped over spine and aorta, thus the neck and body are more superficial than head & tail Small part of the head is contained within the peritoneum PANCREAS ANATOMY Vascular landmarks The SMA, SV, PV, IVC, AO, IVC The CBD, GDA 18 6

7 Normal Pancreas Head, uncinate process, neck, body, tail Ampulla of Vater AKA hepatopancreatic or biliopancreatic ampulla A conical structure at the confluence of the CBD and the main pancreatic duct Encased by smooth muscle fibers that compose the sphincter of Oddi Stones and tumor at the Ampulla of Vater are causes of biliary duct obstruction. 20 Duct Dilatation is usually caused by Stone within the duct/ chronic Pancreatiis Gallstone at the ampulla of Vater Intraductal calcification Dilated duct will appear as an anechoic tubular structure within the pancreas 7

8 GALLBLADDER SCANNING TECHNIQUES Patient Prep NPO a minimum of 6 hours Scanning Techniques Subcostal or intercostal scanning Supine, LLD, LPO, erect, semi-erect GB wall should be measured in long at the anterior wall/ fundus. GB should be imaged in at least two patient positions US: Gold standard, looking for cholelithiasis, cholecystitis, GB polyps, GB carcinoma, cholesterolsis 22 FASTING VS NON FASTING GB Fasting NORMAL GB WALL Non fasting PSEUDOWALL THICKENING 23 GB wall measurement Measure perpendicular, long axis of anterior wall at the fundus. Should measure < 3mm. 24 8

9 GB WALL THICKENING: US VS CT US CT SCAN 25 GALLBLADDER WALL THICKENING CAUSES DIFFUSE 1) Cholecystitis: Acute calculous (gangrenous / emphysematous) Acalculous Chronic / Xanthogranulomatous 2) Secondary causes: (from Liver disease): hepatitis, cirrhosis, portal hypertension. 3) Extracholecystic inflammation (Pancreatitis, Colitis, peritonitis, Pyelonephritis) 4) Sytemic diseases: CHF, Renal failure FOCAL 1)Polyps 2)Malignancy (Primary GB carcinoma, metastases) 3)Focal adenomyomatosis 4)Focal Xanthogranulomatous cholecystitis. 26 CASE SAMPLE

10 CASE SAMPLE 2 28 CASE SAMPLE 3 29 BILIARY TREE DISEASES OBSTRUCTION 1) BENIGN: Choledocholithiasis (MCC) Benign tumors (papillomas, adenomas, cystadenomas) Ampullary tumor Mirizzi syndrome Trauma (from GB surgery for example) 2) MALIGNANT Pancreatic cancer Cholangiocarcinoma INFLAMMATION: Pancreatitis Inflammation of the bile ducts (cholangitis). Biliary stricture (narrowing of the bile duct from scarring). Hepatitis/ enlarged lymph nodes / Parasites (flukes) CONGENITAL: Choledochal cyst/ Caroli disease 30 10

11 CASE SAMPLE 1 31 SAMPLE CASE 2: 32 CASE SAMPLE 3: 33 11

12 PANCREATIC DISEASES INFLAMMATION 1) ACUTE: Pancreatitis. 2) CHRONIC Pancreatitis NEOPLASM Pancreatic cancer 34 CASE SAMPLE 1: CASE SAMPLE 2: 12

13 CASE SAMPLE 3 13