Liver

Describe the complications of cirrhosis of the liver.

simultaneous parenchymal necrosis, regeneration, and diffuse fibrosis, resulting in disorganization of lobular architecture. The disease process is chronic and progressive, with liver cell failure and portal hypertension as the end stage. Cirrhosis is most commonly the result of chronic alcohol abuse but can be the result of nutritional deprivation, hepatitis, or other infection.

What is a recanalized umbilical vein?

umbilical vein may become recanalized secondary to portal hypertension.

How does the blood leave the liver

via the hepatic veins into the inferior vena cava.

Discuss the role of fat metabolism in the liver.

forming, degrading, and storing fats. It has the ability to achieve metabolic interconversion among fats, carbohydrates, and proteins. The liver (through fat metabolism) can make cholesterol and form ketone bodies.

1. Name the two sources that supply blood to the liver.

hepatic artery and the portal vein.

What is the effect of fatty infiltration on the liver?

increased lipid accumulation in the hepatocytes and is the result of significant injury to the liver or a systemic disorder leading to impaired or excessive metabolism of fat. Fatty infiltration is a benign process and may be reversible.

Discuss the development of portal venous hypertension and its effects on the hepatic system.

increased pressure in the portal splenic venous system is the cause of portal hypertension. The hypertension develops when hepatopetal flow (toward the liver) is impeded by thrombus or tumor invasion. The blood becomes obstructed as it passes through the liver to the hepatic veins and is diverted to collateral pathways in the upper abdomen. There are two ways portal hypertension may develop. One is through increased resistance to flow, and the other is in increased portal blood flow.

Name the three basic types of abscess formation in the liver.

intrahepatic, subhepatic, subphrenic (below diaphragm)

What causes biliary obstruction distal to the cystic duct?

A biliary obstruction distal to the cystic duct may be caused by stones in the common duct, an extrahepatic mass in the porta hepatis, or stricture of the common duct.

What are the clinical symptoms and sonographic findings of a liver adenoma?

A liver adenoma is found more commonly in women. Patients may have right upper quadrant pain secondary to rupture, with bleeding into the tumor. There is increased incidence in patients with Type I glycogen storage disease or von Gierke's disease. On ultrasound examination, the mass may look similar to focal nodular hyperplasia. It is hyperechoic with a central hypoechoic area caused by hemorrhage. The lesion may be solitary or multiple. If the lesion ruptures, fluid should be found in the peritoneal cavity.

What is the definition of a neoplasm?

A neoplasm is any new growth of new tissue, either benign or malignant. If the neoplasm is benign, growth occurs locally but does not spread or invade surrounding structures. A malignant mass is uncontrolled and is prone to metastasize to nearby or distant structures via the bloodstream and lymph nodes.

Describe the characteristic findings of an amebic abscess.

An amebic abscess is a collection of pus formed by disintegrated tissue in a cavity, usually in the liver, caused by the protozoan parasite Entamoeba histolytica.

What causes biliary obstruction proximal to the cystic duct?

Biliary obstruction proximal to the cystic duct can be caused by carcinoma of the common bile duct, or metastatic tumor invasion of the porta hepatis. Clinically the patient may be jaundiced and may experience pruritus (itching). The liver function tests show an elevation in the direct bilirubin and alkaline phosphatase levels.

Describe the findings of a cavernous hemangioma.

Cavernous hemangioma is the most common benign tumor of the liver. Hemangiomas enlarge slowly and undergo degeneration, fibrosis, and calcification. They are found in the subcapsular hepatic parenchyma or in the posterior right lobe more often than in the left lobe of the liver. The ultrasound appearance of hemangiomas is typical in that most are hyperechoic with acoustic enhancement. They are either round, oval, or lobulated, with well-defined borders.

Name the common causes of fatty liver.

Common causes of fatty liver include the following: alcoholic liver disease, diabetes mellitus, obesity, severe hepatitis, chronic illness, and steroids.

How does diffuse hepatocellular disease affect the hepatocytes in the liver?

Diffuse hepatocellular disease affects the hepatocytes and interferes with liver function.

Describe the sonographic findings and incidence of focal nodular hyperplasia.

Focal nodular hyperplasia lesions occur in the right lobe of the liver. There may be more than one mass; many are located along the subcapsular area of the liver; some are pedunculated; and many have a central scar. On ultrasound examination, the lesions appear well defined and show hyperechoic to isoechoic patterns as compared with the liver.

What complications may arise after liver transplant?

Hepatic artery thrombosis is the most serious complication of liver transplantation. The development of anastomotic stenoses is another problem that may occur in the transplant patient. The flow pattern of this complication shows a turbulent, high-velocity signal indicative of hepatic artery stenosis. Portal vein thrombosis also may occur in the postoperative period. Air in the portal vein may be seen as bright, echogenic moving targets within the portal venous system. Compromise of the IVC is another complication of transplantation. A fatal complication is hepatic necrosis associated with thrombosis of the hepatic artery or portal vein.

What is the name given to liver cells

Hepatocytes

Describe the difference between acute and chronic hepatitis.

In acute hepatitis, damage to the liver may range from a mild disease to massive necrosis and liver failure. Hepatosplenomegaly is present, and the gallbladder wall is thickened. Chronic hepatitis exists when there is clinical or biochemical evidence of hepatic inflammation for at least 3 to 6 months. Chronic persistent hepatitis is a benign, self-limiting process. Chronic active hepatitis usually progresses to cirrhosis and liver failure.

What are the clinical and sonographic findings of metastatic liver disease?

In metastatic liver disease, clinically the patient has hepatomegaly, abnormal liver function tests, weight loss, and decreased appetite. It is typical for this disease to occur in multiple nodes throughout both lobes of the liver. The ultrasound patterns of metastatic tumor involvement in the liver vary. Three specific patterns have been described: 1. well-defined hypoechoic mass; 2. well-defined echogenic mass; and 3. diffuse distortion of normal homogeneous parenchymal pattern without focal mass. The hypovascular lesions produce hypoechoic patterns in the liver as a result of necrosis and ischemic areas from neoplastic thrombosis.

Describe the ultrasound appearance of fatty infiltration of the liver.

Moderate to severe fatty infiltration shows increased echogenicity on ultrasound examination. Enlargement of the lobe affected by the fatty infiltration is evident. Moderate to severe fatty infiltration shows increased echogenicity on ultrasound examination. Enlargement of the lobe affected by the fatty infiltration is evident.

Describe the ultrasound appearance of an echinococcal cyst of the liver.

On ultrasound examination, several patterns may occur, from a simple cyst to a complex mass with acoustic enhancement. The shape of the cyst may be oval or spherical, and may have regularity of the walls. Calcifications may occur.

Describe the clinical findings in a patient with hepatitis.

Patients with hepatitis may present initially with flu and gastrointestinal symptoms, including loss of appetite, nausea and vomiting, and fatigue. Jaundice may occur in severe cases. Laboratory values show abnormal liver function tests, with increases in the ALT, AST, and bilirubin.

Describe the appearance of lymphoma of the liver.

Patients with lymphoma of the liver have hepatomegaly, with a normal or diffuse alteration of parenchymal echoes. A focal hypoechoic mass may be seen sometimes. The presence of splenomegaly or retroperitoneal nodes may help confirm the diagnosis of lymphadenopathy.

What is the metabolic physiology of carbohydrates in the liver?

Simple sugars freely enter the liver cells, where they are converted to glucose. The glucose pool in the liver can be easily exchanged with that in the blood.

Describe the role of amino acids within the liver.

The amino acids within the liver cells form a pool that can be used to make the various proteins of the liver and blood as well as glucose, fats, and energy.

What does an ultrasound evaluation of the liver parenchyma include?

The evaluation of the liver parenchyma includes the assessment of its size, configuration, homogeneity, and contour examined in a supine, right anterior oblique position in a transverse, coronal, subcostal oblique, and sagittal view to completely survey the organ.

Describe the pathway of the blood as it flows into the liver.

The incoming arterial blood and portal blood are mixed as they flow into the liver sinusoids. The hepatocytes take oxygen and nutrients from this blood, and then the blood flows into the hepatic veins.

Discuss the development of collateral circulation.

occurs when the normal venous channels become obstructed. diverted blood flow causes embryologic channels to reopen; blood flows hepatofugally (away from the liver) and is diverted into collateral vessels. The collateral channels may be the gastric veins (coronary veins); esophageal veins; recanalized umbilical veins; and splenorenal, gastrorenal, retroperitoneal, hemorrhoidal, and intestinal veins

Trace the path of bile after the hepatocytes form bile in the liver.

secrete it into small canaliculi, which coalesce to form the bile ducts. In these ducts, bile flows in the opposite direction of arterial blood to prevent mixing. The bile ducts coalesce to form the hepatic duct, which emerges from the liver. The hepatic duct bifurcates to form the cystic duct, which leads to the gallbladder and the common bile duct. Together with the pancreatic duct, they empty into the duodenum.

What role does the liver play in the hormonal regulation of blood sugar

The liver is the major organ regulating the balance of blood sugar and carbohydrate metabolism. The liver has enzymes that convert glycogen to glucose, glycerol to glucose, and vice versa, and amino acids to glucose and the reverseThe liver has a special enzyme to free glucose and is the only organ that can secrete glucose into the blood when the level of this substance exceeds the blood level. The liver helps to maintain a steady state of glucose in the bloodstream.

Discuss the various portal caval shunts available and what considerations the sonographer should have before the examination.

The portacaval shunt attaches the main portal vein at the superior mesenteric vein-splenic vein confluence to the anterior aspect of the IVC.

Discuss the incidence and findings of liver trauma.

The right lobe is affected more often than the left. The degree of trauma is variable and may include small lacerations, large lacerations with hematomas, subcapsular hematomas, or capsular disruptions. Intraperitoneal fluid should be assessed along the flanks and into the pelvis.

What diseases cause an elevation of both direct(conjugated) and indirect(unconjugated) bilirubin?

Total bilirubin is the elevation of both direct (conjugated) and indirect (unconjugated) bilirubin levels in hepatic metastasis, hepatitis, lymphoma, cholestasis secondary to drugs, and cirrhosis, but the increase in the direct level is more marked.

What is the role of ultrasound in liver transplantation?

significant role in the preoperative and postoperative evaluation of hepatic transplantation. The primary function of the ultrasound examination is the evaluation of the portal venous system, the hepatic artery and veins, the IVC, and the liver parenchymal pattern.

Discuss the three patterns of hepatocellular carcinoma.

as a solitary massive tumor, multiple nodules throughout the liver, or diffuse infiltrative masses in the liver.

What is the composition of bile

bile acids and salts, phospholipids, cholesterol, pigments, water, and electrolyte chemicals that keep the total solution slightly alkaline (with a pH of about 7 to 8)

What are the clinical findings in a patient with portal hypertension?

clinically the patient presents with ascites, hepatosplenomegaly, gastrointestinal bleeding, elevated liver enzymes, jaundice, and hematemesis.

Name the primary sites that cause metastatic disease to spread to the liver.

colon, breast, and lung.

Discuss the sonographic findings of a cirrhotic liver.

course texture of the liver parenchyma secondary to fibrosis and nodularity. Increased attenuation may be present, with decreased vascular markings. Hepatosplenomegaly may be present, with ascites surrounding the liver. Chronic cirrhosis may show nodularity of the liver surfaces, especially if ascites is present. The hepatic fissures may be accentuated. The isoechoic regenerating nodules may be seen throughout the liver parenchyma. Portal hypertension may be present with or without abnormal Doppler flow patterns.