Abdominal Sonography Exam 2 PDF

Anatomy of the Biliary System 1. Gallbladder: - Length: 7-10 cm 1. Components: - Diameter: 2.5-4 cm - Right and left hepatic duct...

Anatomy of the Biliary System 1. Gallbladder: - Length: 7-10 cm 1. Components: - Diameter: 2.5-4 cm - Right and left hepatic ducts - Wall thickness: ≤3 mm - Common hepatic duct 2. Common Bile Duct: - Common bile duct (CBD) - Normal diameter at porta hepatis: 1-6 mm - Gallbladder - Elderly patients: Up to 10 mm considered normal - Cystic duct - Measurement technique: Inner-to-inner 2. Bile Duct Classification: - Intrahepatic ducts: All portions within the liver Bile Production and Flow: - Extrahepatic ducts: Common bile duct, cystic duct, and part of 1. Production: common hepatic duct - Liver produces 500-1000mL of bile daily 3. Gallbladder Anatomy: - Composition: Water, electrolytes, bile salts, lipids, and bile pigments - Location: Posterior to right lobe of liver within gallbladder fossa 2. Transport Sequence: - Classification: Intraperitoneal organ - Liver cells secrete bile into right and left hepatic ducts - Landmark: Main lobar fissure - Ducts drain into common hepatic duct - Parts (superior to inferior): - Joins with cystic duct to form common bile duct * Fundus - About 50% stored in gallbladder * Body - Released into duodenum during digestion * Neck * Connects to cystic duct Function: 4. Gallbladder Wall: 1. Bile Functions: - Three distinct layers - Aids digestion/absorption of lipids and fat-soluble vitamins * Mucosal layer - Eliminates waste products * Fibromuscular layer - Neutralizes gastric acid in small intestine * Serosal layer 2. Gallbladder Functions: - Concentrates bile Normal Measurements and Parameters: - Stores bile - Releases bile in response to meals Special Considerations: Ultrasound Examination: 1. Postprandial State: 1. Scanning Requirements: - Gallbladder appears contracted - Transducer: 5 MHz or higher - Shows diffuse wall thickening - Patient preparation: 8-12 hour fast (minimum 6-8 hours) - Normal response to eating - Timing: Morning scan preferred 2. Wall Thickness Measurement: 2. Patient Positioning: - Must be measured on anterior wall - Supine and left lateral decubitus - Only measure in transverse view - Purpose: To assess for movable intraluminal objects - Normal: ≤3 mm 3. Indications for Gallbladder Ultrasound: - Abdominal pain after eating - Right upper quadrant or epigastric pain - Jaundice - Atypical right-sided chest/shoulder pain - Abnormal liver function tests Common Anatomical Variations: 1. Junctional Fold: - Most common variant - Located between neck and body 2. Hartmann's Pouch: - Gallbladder fold at neck - Common site for stone collection 3. Phrygian Cap: - Folding of gallbladder fundus 4. Septated Gallbladder: - Can be partial or complete septation Pancreas Anatomy & Physiology Anatomical Parts: 1. Uncinate Process: Basic Characteristics: - Extension of pancreatic head - Retroperitoneal organ/gland in epigastrium and left hypochondrium - Variable in size/shape - Bounded anteriorly by stomach and duodenum - Passes downward/left from head - Comma-shaped, non-encapsulated organ - Located posterior to superior mesenteric vessels - Approximately 12 cm long and 2 cm thick - Anterior to aorta/inferior vena cava - Extends from duodenal concavity to splenic hilum 2. Head: - Located in duodenal C-loop Functions: - Anterior to inferior vena cava 1. Endocrine (10% of gland): - Inferior to portal vein - Performed by islets of Langerhans - GDA located on anterior portion - Contains three main cell types: - CBD located on posterior portion * Alpha cells: Produce glucagon 3. Neck: * Beta cells: Produce insulin - 1.5-2.0 cm long * Delta cells: Produce somatostatin - Site of superior mesenteric vessels passage - Hormones released directly into bloodstream - Location where portal vein forms - Controls blood sugar levels - Junction point of superior mesenteric and splenic veins 2. Exocrine (90% of gland): 4. Body: - Acini cells secrete: - Largest part of the gland * Enzymes (amylase, lipase, trypsin) - Posterior to stomach * Sodium bicarbonate - Anterior to portal vein origin - Drainage pathway: - Rests anterior to: * Into main pancreatic duct (Wirsung's duct) * Aorta * Through ampulla of Vater * Left renal vessels * Mixes with bile from liver * Left adrenal gland * Released into duodenum via sphincter of Oddi * Left kidney * Superior mesenteric artery origin - Bordered by: * Portal vein * Superior: Tortuous splenic artery * Splenic vein * Posterior: Splenic vein joins portal vein * Superior/inferior mesenteric veins 5. Tail: - Anterior to left kidney Portal Vein Anatomy - Close to spleen - Formed posterior to pancreatic neck - Bordered by: - Formed by junction of: * Superior: Splenic artery * Superior mesenteric vein (SMV) * Posterior: Splenic vein * Splenic vein (SV) * Superior-anterior: Stomach * SMV runs posterior to lower neck, anterior to uncinate process * Splenic vein runs along posterior superior pancreas from splenic Ductal System hilum 1. Main Pancreatic Duct (Wirsung's): - Primary duct extending entire gland length Ultrasound Imaging - Enters duodenum's second part with CBD Normal Measurements: - Joins at Vater's ampulla - Head: AP 2.0-2.5 cm 2. Accessory Duct (Santorini's): - Body: AP 1.0-1.5 cm - Secondary duct - Tail: AP 0.5-3.0 cm - Drains upper anterior head - Pancreatic duct: 2mm (decreases toward tail) - Enters duodenum at minor papilla - Located ~2cm proximal to Vater's ampulla Scanning Technique: - Most difficult abdominal organ to image Vascular Supply - Patient preparation: Arterial: * 6-8 hour fast - Head: Supplied by gastroduodenal artery * Promotes duct dilation - Body/Neck/Tail: Supplied by splenic and superior mesenteric arteries * Reduces bowel gas Venous: * Ensures empty stomach - Drains to: Indications: * Ends at portal confluence - Epigastric/left sided abdominal pain * Important landmark for pancreas: - Weight loss - Head is lateral - Jaundice - Neck is anterior - Diarrhea - Uncinate process is posterior - Bloating - New-onset diabetes Sonographic Differentiation - Important not to confuse SMV with splenic vein Special Techniques: - Longitudinal SMV view on sagittal scan Water Technique: - Longitudinal SV view on transverse scan - 32-300ml water through straw - SMA, aorta & spine posterior to splenic vein - Patient upright isoechoic hyperechoic - Uses stomach as acoustic window Congenital Anomalies * 1. Pancreas Divisum: Echotexture: - Failure of dorsal and ventral pancreatic primordia (embryologic - Varies with fat content ducts) to fuse - Either isoechoic or hyperechoic compared to liver - May result in separate draining of the ducts of Wirsung and Santorini - Children: Usually isoechoic to liver 2. Annular Pancreas: - Adults: More echogenic due to increased fat - A thin, flat band of normal pancreatic tissue surrounding the second part of the duodenum Sonographic Vascular Markers - Continues into the head of the pancreas on either side - Splenic vein characteristics: - Duodenum under anulus is usually stenosed * Posterior to body & tail 3. Pancreatic Gallbladder: * Ends at portal confluence - Pancreatic tissue present in the wall of an otherwise normal * Has "cobra head" or "scallion" appearance on ultrasound gallbladder * Key marker for body & tail 4. Ectopic Pancreas: - SMV characteristics: - Pancreatic tissue found in abnormal locations * Courses parallel and right of SMA - Common locations:  * Stomach * Duodenal wall * Umbilicus - 50% occur in duodenum or pylorus - Less common sites: * Colon * Appendix * Gallbladder - Most ectopic pancreatic tissue is functional 5. Intraperitoneal Pancreas: - Condition where the head and part of the body of the pancreas are found intraperitoneally - Normally pancreas is retroperitoneal, so this represents an anatomical variation transverse normal SMA IVC A GASTROINTESTINAL (GI) TRACT - Main digestive region - Contains most parietal cells Anatomical Structure & Organization * Pyloric Antrum: * Complete alimentary canal measuring approximately 30 feet - Terminal portion * Highly specialized muscular tube with varying diameters - Regulates gastric emptying * Complex vascular supply: * Pylorus: - Celiac axis: Upper GI tract - Sphincter control mechanism - Superior mesenteric artery (SMA): Mid-gut structures - Regulates duodenal entry - Inferior mesenteric artery (IMA): Lower GI tract * Functionally divided into: SMALL INTESTINE - Upper GI tract (mouth to duodenum) Duodenum - Lower GI tract (jejunum to anus) * Unique C-shaped configuration * Retroperitoneal positioning (except first portion) DETAILED STOMACH ANATOMY & PHYSIOLOGY * Four distinct parts: Anatomical Position 1. Superior (bulb) * Primary location: Left upper quadrant 2. Descending * Anatomical relations: 3. Horizontal - Superior: Diaphragm 4. Ascending - Anterior: Abdominal wall * Key relationships: - Posterior: Pancreas - Pancreatic duct entry - Lateral: Spleen - Common bile duct connection - Medial: Liver - Major/minor papilla Structural Components Jejunum 1. Wall Structure: * Characteristics: * Multiple specialized layers - Thicker wall than ileum * Muscular thickness varies by region - More vascular supply * Rugae formation for expansion - Larger circular folds * Location: Left upper abdomen 2. Major Regions: * Length: Approximately 2 meters * Cardia: * Function: Primary nutrient absorption - Located at gastroesophageal junction - Contains lower esophageal sphincter Ileum * Fundus: * Distinguishing features: - Superior portion - Thinner wall - Important for gas collection - More lymphatic tissue * Body: - Peyer's patches present * Terminal ileum: SONOGRAPHIC EXAMINATION TECHNIQUES (DETAILED) - Important landmark Transabdominal Technique - Ileocecal valve location * Equipment requirements: - Critical for bacterial control - High-frequency transducers (5-12 MHz) - Multiple focal zones LARGE INTESTINE STRUCTURE - Appropriate depth settings Anatomical Segments * Scanning protocols: 1. Cecum: - Systematic approach required * Blind pouch beginning - Multiple planes examined * Appendix attachment site - Compression techniques utilized * Located in right iliac fossa * Patient positioning: - Supine position primary 2. Ascending Colon: - Left lateral decubitus as needed * Retroperitoneal position - Modified positions for specific views * Extends to hepatic flexure * Right-sided positioning Endoluminal Examination * Specialized equipment: 3. Transverse Colon: - High-frequency miniature transducers * Intraperitoneal portion - Purpose-built endoscopes * Most mobile segment - Dedicated processing units * Forms hepatic and splenic flexures * Applications: - Upper GI tract evaluation 4. Descending Colon: - Rectal/anal assessment * Retroperitoneal again - Cancer staging * Left-sided positioning * Technical considerations: * More fixed position - Requires special training - Real-time imaging capability 5. Sigmoid Colon: - Superior resolution for wall layers * S-shaped configuration * Most narrow diameter PATIENT PREPARATION PROTOCOLS * High mobility Pre-examination Requirements * Fasting guidelines: 6. Rectum: - 8-12 hours minimum * Terminal portion - Clear liquids allowed * No haustra - Medication considerations * Specialized function * Specific preparations: - Upper GI: Water loading  - Lower GI: Possible bowel prep - Wall thickening - Emergency cases: Modified protocols - Loss of compressibility - Surrounding inflammation SONOGRAPHIC WALL STRUCTURE * Technical considerations: Detailed Layer Examination - Patient position optimization 1. Superficial Mucosa: - Graded compression technique * Echogenic appearance - Multiple plane imaging * Interface with lumen * Thickness variations ADVANCED IMAGING CONSIDERATIONS Technical Optimization 2. Deep Mucosa: * Equipment selection: * Hypoechoic layer - Transducer frequency choice * Cellular content - Focus position adjustment * Inflammatory markers - Gain settings optimization * Image acquisition: 3. Submucosa: - Multiple plane documentation * Bright echogenic band - Dynamic assessment * Vascular network - Cine loop recordings * Pathological indicators * Quality assurance: - Standard protocols 4. Muscularis Propria: - Documentation requirements * Hypoechoic appearance - Image optimization techniques * Thickness measurements * Motility assessment 5. Serosa: * Outer echogenic line * Inflammatory changes * Pathological involvement APPENDIX SONOGRAPHIC EVALUATION Detailed Assessment Protocol * Measurement criteria: - Maximum diameter ≤ 6mm - Wall thickness assessment - Compressibility evaluation * Pathological indicators: