Hepatobiliary System - MRD515 Radiographic Pathology PDF

HEPATOBILIARY SYSTEM MRD515 RADIOGRAPHIC PATHOLOGY  ANATOMY AND PHYSIOLOGY Liver The largest organ in the body, is situated in the right upper quadrant of the abdomen, protected by the ribs and held in place by peritoneal ligaments and abdominal pressure....

HEPATOBILIARY SYSTEM MRD515 RADIOGRAPHIC PATHOLOGY  ANATOMY AND PHYSIOLOGY Liver The largest organ in the body, is situated in the right upper quadrant of the abdomen, protected by the ribs and held in place by peritoneal ligaments and abdominal pressure. Functions: metabolism of substances from the portal circulation, synthesis of blood clotting substances and vitamins, and detoxification. Blood Supply: The liver receives blood from two sources: the hepatic artery (oxygenated blood) and the portal vein (venous blood from the abdominal viscera).  Comprises ducts that transport bile from the liver to the duodenum. The right and left hepatic ducts merge to form the common hepatic duct, which joins with the cystic duct from the gallbladder to create the common bile duct. The common bile duct may join with the pancreatic duct before entering the duodenum at the hepatopancreatic ampulla (ampulla of Vater). The sphincter of Oddi controls the flow of bile and pancreatic juice into the duodenum, with bile release triggered by cholecystokinin in response to fatty foods.  Gallbladder: A pear-shaped sac located under the liver's right lobe, the gallbladder stores and concentrates bile produced by the liver, releasing it into the duodenum to aid fat digestion. Pancreas: An elongated organ behind the stomach, crossing the left abdomen. Functions: 1.Exocrine: Produces digestive enzymes (trypsin, amylase, lipase) for protein, starch, and lipid digestion, discharging them into the duodenum. 2.Endocrine: Houses islets of Langerhans (α- cells and β-cells) for insulin and glucagon production, regulating carbohydrate metabolism.  IMAGING CONSIDERATIONS Radiography: 1. Abdominal Radiograph: Useful for identifying calcifications in the hepatobiliary system and detecting radiopaque gallstones in the gallbladder. 2. Gas Visualization: Gas in the gallbladder or biliary tree can indicate infection or complications like gallstone ileus or postoperative issues. Contrast Studies Percutaneous Transhepatic Cholangiography (PTC): Involves inserting a needle into the biliary tree to inject contrast medium, useful for differentiating medical from surgical jaundice and detecting obstructions or tumors. Contrast Studies Endoscopic Retrograde Cholangiopancreatogram (ERCP): A gastroenterologist performs this to visualize the biliary system and pancreatic duct, useful for evaluating obstructions, bleeding disorders, and pancreatic issues. Contrast Studies: Operative Cholangiography: Conducted during surgery like cholecystectomy to detect biliary calculi. Contrast Studies: T-Tube Cholangiography: Post-cholecystectomy procedure to ensure the common bile duct is clear of calculi. IMAGING CONSIDERATIONS Real-Time Sonography: The preferred noninvasive method for evaluating the gallbladder and biliary tree, highly accurate in detecting gallstones and assessing the liver. IMAGING CONSIDERATIONS Computed Tomography (CT): Role in Hepatobiliary System: Essential for following malignancies, assessing masses, and evaluating complications like cholecystitis. Advantages: Offers excellent contrast resolution and can be enhanced with IV contrast media for dynamic examination. IMAGING CONSIDERATIONS Nuclear Medicine Procedures: Single Photon Emission Computed Tomography (SPECT): Useful for detecting deep hepatobiliary lesions and evaluating hepatic function and perfusion. Cholescintigraphy: Helps confirm cholecystitis and differentiate between acute and chronic forms. IMAGING CONSIDERATIONS Magnetic Resonance Imaging (MRI): MRI Applications: Used alongside CT for evaluating pathologies and anomalies, especially in the liver and pancreas. Magnetic Resonance Cholangiopancreatography (MRCP): Noninvasive imaging of the gallbladder and biliary system without contrast agents. INFLAMMATORY DISEASES  Alcohol-Induced Liver Disease Alcohol as a Toxin: When the liver processes alcohol, it causes cell damage and is linked to various liver diseases. Metabolism Process: The liver changes alcohol into substances like alcohol dehydrogenase, acetaldehyde, and acetate. This affects cell function and disrupts fat and carbohydrate processing in the body. Disease Stages: Fatty Liver: Early stage of alcohol-related liver disease. Fat builds up in liver cells, often without symptoms but can lead to an enlarged liver. Detected using CT scans or sonography. Alcoholic Hepatitis: Inflammation and damage in the liver following fatty changes, often with jaundice. Can lead to liver cell death and, in severe cases, liver failure. Alcoholic Cirrhosis: Advanced stage, with severe liver scarring. Develops if hepatitis is survived.  Imaging Techniques: Hepatobiliary Scan: Shows how substances move from the gallbladder to the small intestine. MRI: Used for detailed liver imaging without needing contrast dyes, and helps in spotting fatty deposits in the liver.  Fatty Liver Disease Nonalcoholic Fatty Liver Disease (NAFLD), a liver condition where fat builds up, not due to alcohol, but other factors. People who are obese, have type 2 diabetes, metabolic syndrome, or hyperlipidemia are more likely to develop NAFLD. Fats accumulate in liver cells (hepatocytes), leading to excess fatty acids in the liver, a state known as steatosis or fatty liver disease. Early stages usually show no symptoms, making detection difficult without a liver biopsy. If untreated, NAFLD can slowly progress to more severe liver conditions like cirrhosis. Key strategies include weight loss and exercise to address insulin resistance and metabolic problems. CT scans are used to detect fatty liver infiltration, indicating NAFLD.  Cirrhosis A chronic liver disease where normal liver tissue is replaced by fibrous tissue and regenerative nodules, leading to liver dysfunction. Causes: Chronic alcohol abuse, drugs, autoimmune disorders, metabolic and genetic diseases, chronic hepatitis, heart problems, and chronic biliary tract obstruction. Asymptomatic Early Stages: Damage may take months or years to become apparent. Symptoms: Include jaundice, portal hypertension, and complications like esophageal varices and ascites. Complications: Portal Hypertension: Increased pressure in the portal vein system, leading to complications like esophageal varices. Ascites: Accumulation of fluid in the abdominal cavity, contributing to about 50% of deaths from cirrhosis.  Radiography: Used to assess the extent of ascites and other complications. CT and MRI: Essential for evaluating liver morphology and detecting hepatic carcinoma. Biopsy: Often necessary for a definitive diagnosis Doppler Sonography: Used to detect portal hypertension and evaluate blood flow. Treatment: Goal: To address the underlying causes and manage complications. Surgical Options: Include shunts to reduce portal hypertension and procedures like TIPSS (Transjugular Intrahepatic Portosystemic Shunt). Liver Transplantation: Offers a potential long-term solution for advanced cases.  Viral Hepatitis Common liver condition which interferes with the liver’s ability to excrete bilirubin, the orange or yellowish pigment in bile. At least six types of viruses causing acute liver inflammation. Hepatitis A (HAV): Spread through fecal-oral route; mild course; does not lead to chronic hepatitis or cirrhosis. Hepatitis B (HBV): Transmitted through blood; can lead to chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Hepatitis C (HCV): Often transmitted through blood transfusions; can cause acute or chronic hepatitis, leading to cirrhosis. Hepatitis D (HDV): Occurs only with HBV infection. Hepatitis E (HEV): Waterborne; common in developing countries; severe but not chronic. Hepatitis G (HGV): Newly identified; transmitted via blood; may cause chronic hepatitis.  Symptoms: Include nausea, vomiting, liver tenderness, fatigue, anorexia, and jaundice. Diagnosis: Made through laboratory testing; imaging like CT, MRI, sonography, and liver biopsy (gold standard) can confirm the type of disease Treatment: General Approach: Bed rest and medication for nausea and vomiting. Specific Treatments: Depend on the type of hepatitis; chronic types may lead to liver failure. Prevention: Vaccinations: Especially for HBV, have significantly reduced infection rates.  Cholelithiasis (Gallstones) Risk Factors: Include gender (more common in women), obesity, diabetes, and a diet high in saturated fat and low in fiber. Composition: Mostly cholesterol, bile pigment, and calcium salts. Appearance: Mostly radiolucent; only 10% contain enough calcium to be radiopaque. Symptoms: May include bloating, nausea, and right upper quadrant pain. Diagnosis: Sonography is effective in detecting gallstones. Surgical Removal: Cholecystectomy, often performed laparoscopically. Sonography: Used for initial diagnosis. Cholescintigraphy, CT, MRI: Recommended for comprehensive assessment. Radiography in Surgery: Used to ensure all stones are removed during cholecystectomy.  Cholecystitis Acute Inflammation: Of the gallbladder, often associated with cholelithiasis (gallstones). Symptoms: Sudden onset of pain, fever, nausea, and vomiting. Radionuclide Cholescintigraphy: Uses technetium-99m for visualizing the biliary ductal system, best image for perforation Sonographic & CT demonstrate a nonspecific pericholecystic fluid collection Stones may be visible outside the gallbladder on conventional abdominal radiographs, CT images, or sonographic images. Nonvisualization of Gallbladder: Indicates acute cholecystitis. Complications: Repeated Attacks: Lead to gallbladder damage, wall thickening, and decreased function. Severe Cases: Can lead to infarction, gangrene, and rupture. Treatment: Surgical Removal: Laparoscopic removal of the inflamed gallbladder is common. Pancreatitis Inflammation of Pancreatic Tissue Acute Pancreatitis: Resolves without permanent damage. Chronic Pancreatitis: Leads to irreversible changes in pancreatic function. Causes: excessive and chronic alcohol consumption, obstruction of the hepatopancreatic ampulla by a gallstone or tumor, and even the injection of contrast media during ERCP Hemorrhagic pancreatitis is a complication of pancreatitis Symptoms: Range from mild abdominal pain to severe pain and shock.  CT has made a major contribution to the diagnosis and staging of acute pancreatitis. Sonography is good for assessing the texture and size of the organ. ERCP helps determining the reasons for acute recur-rent pancreatitis, chronic pancreatitis, or the complications associated with pancreatitis. Treatment and Management: Mild Cases: Pain relief and fluid management. Severe Cases: May require more intensive treatment and monitoring. Prognosis: Depending on the severity and presence of complications like pancreatic necrosis.  Jaundice Sign, Not a Disease: Yellowish discoloration of skin and eyes due to excess bilirubin. Medical (Nonobstructive) Jaundice: Due to hemolytic disease or liver damage. Surgical (Obstructive) Jaundice: Caused by obstruction in the biliary system. Sonographic Examination: Differentiates between obstructive and nonobstructive jaundice. The common bile duct is readily identified; generally, a normal size implies nonobstructive jaundice, and a dilated common bile duct suggests an obstruction. ERCP, MRCP, and CT used to diagnose the cause of jaundice Treatment: Depends on Underlying Cause: Surgical excision or endoscopic removal for obstructive jaundice. NEOPLASTIC DISEASES Hepatocellular Adenoma Nature: Benign liver tumor, often asymptomatic. Prevalence: Increased incidence, particularly in women using oral contraceptives. Imaging: CT and sonography are effective in identifying hepatic lesions. Hemangioma Description: Common benign liver tumor made of blood vessels. Prevalence: More common in women, particularly postmenopausal. Imaging Techniques: Sonography: Can detect changes in size or character. Nuclear Medicine Scans: Use labeled RBCs for diagnosis. CT and MRI: Show peripheral enhancement and hyperintensity on T2-weighted images. Hepatocellular Carcinoma (Hepatoma) Nature: Primary liver cancer, often linked to cirrhosis and hepatitis B or C. Symptoms: Include jaundice, abdominal pain, weight loss, and liver enlargement. Imaging and Diagnosis: Sonography, CT, arteriography, and liver biopsy. Treatment: Surgical resection, chemotherapy, and possibly liver transplantation.  Metastatic Liver Disease Prevalence: More common than primary liver cancer. Primary Sources: Cancers from colon, pancreas, stomach, lung, and breast. Diagnosis: Sonography, CT, MRI, and liver biopsy. Treatment: Combination of medication and transarterial embolization. Carcinoma of the Gallbladder Nature: Often malignant, with a high incidence of adenocarcinomas. Symptoms: Nonspecific, including pain, jaundice, and weight loss. Imaging: CT and sonography. Prognosis: Generally poor due to early metastasis.  Carcinoma of the Pancreas Nature: Rapidly fatal, often diagnosed late due to nonspecific symptoms. Risk Factors: Smoking, alcoholism, chronic pancreatitis, diabetes, and family history. Imaging: CT, sonography, MRI, and barium studies. Treatment: Radical surgery, radiation therapy, and chemotherapy. Prognosis: Extremely poor, with a low 5-year survival rate. Key Takeaways of Neoplastic disease Imaging Techniques: Advanced imaging methods like CT, MRI, and sonography play a crucial role in diagnosing these conditions. Treatment Challenges: Many of these conditions, especially carcinomas, have limited treatment options and poor prognoses. Importance of Early Detection: Early diagnosis is critical, especially for conditions like hepatocellular carcinoma and pancreatic cancer, where late detection often leads to poor outcomes. THANK YOU