Transient hepatic attenuation differences

Last updated
An abscess and a THAD (white arrow) on a contrast CT in native, arterial, portal and delayed phase. CT of abscess and THAD.jpg
An abscess and a THAD (white arrow) on a contrast CT in native, arterial, portal and delayed phase.

Transient hepatic attenuation differences (THAD) are areas of enhancement during the arterial phase of contrast CT of the liver. THAD is thought to be a physiological phenomenon resulting from regional variation in the blood supply by the portal vein and/or the hepatic artery. THAD may in some cases be associated with liver tumors such as a hepatocellular carcinoma. [2]

Contrast CT

Contrast CT is X-ray computed tomography (CT) using radiocontrast. Radiocontrasts for X-ray CT are, in general, iodine-based types. This is useful to highlight structures such as blood vessels that otherwise would be difficult to delineate from their surroundings. Using contrast material can also help to obtain functional information about tissues. Often, images are taken both with and without radiocontrast. CT images are called precontrast or native-phase images before any radiocontrast has been administrated, and postcontrast after radiocontrast administration.

Portal vein

The portal vein or hepatic portal vein is a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver. This blood contains nutrients and toxins extracted from digested contents. Approximately 75% of total liver blood flow is through the portal vein, with the remainder coming from the hepatic artery proper. The blood leaves the liver to the heart in the hepatic veins.

Liver tumors are tumors or growths on or in the liver. Several distinct types of tumors can develop in the liver because the liver is made up of various cell types. These growths can be benign or malignant (cancerous). They may be discovered on medical imaging, or may be present in patients as an abdominal mass, hepatomegaly, abdominal pain, jaundice, or some other liver dysfunction.

Related Research Articles

Elastography

Elastography is a medical imaging modality that maps the elastic properties and stiffness of soft tissue. The main idea is that whether the tissue is hard or soft will give diagnostic information about the presence or status of disease. For example, cancerous tumours will often be harder than the surrounding tissue, and diseased livers are stiffer than healthy ones.

Hyperammonemia

Hyperammonemia is a metabolic disturbance characterised by an excess of ammonia in the blood. It is a dangerous condition that may lead to brain injury and death. It may be primary or secondary.

Acute liver failure rapid deterioration of liver function causing encephalopathy and coagulopathy

Acute liver failure is the appearance of severe complications rapidly after the first signs of liver disease, and indicates that the liver has sustained severe damage. The complications are hepatic encephalopathy and impaired protein synthesis. The 1993 classification defines hyperacute as within 1 week, acute as 8–28 days, and subacute as 4–12 weeks. It reflects the fact that the pace of disease evolution strongly influences prognosis. Underlying cause is the other significant determinant of outcome.

Liver biopsy

Liver biopsy is the biopsy from the liver. It is a medical test that is done to aid diagnosis of liver disease, to assess the severity of known liver disease, and to monitor the progress of treatment.

Hepatic veins

In human anatomy, the hepatic veins are the veins that drain de-oxygenated blood from the liver into the inferior vena cava. There are usually three upper hepatic veins draining from the left, middle, and right parts of the liver. These are larger than the group of lower hepatic veins that can number from six to twenty. All of the hepatic veins drain into the inferior vena cava.

Transjugular intrahepatic portosystemic shunt

Transjugular intrahepatic portosystemic shunt is an artificial channel within the liver that establishes communication between the inflow portal vein and the outflow hepatic vein. It is used to treat portal hypertension which frequently leads to intestinal bleeding, life-threatening esophageal bleeding and the buildup of fluid within the abdomen (ascites).

Hepatic artery proper

The hepatic artery proper is the artery that supplies the liver and gallbladder. It raises from the common hepatic artery, a branch of the celiac artery.

A portosystemic shunt or portasystemic shunt (PSS), also known as a liver shunt, is a bypass of the liver by the body's circulatory system. It can be either a congenital or acquired condition.

Pulsatile intravenous insulin therapy, sometimes called metabolic activation therapy, or cellular activation therapy describes in a literal sense the intravenous injection of insulin in pulses versus continuous infusions. Injection of insulin in pulses mimics the physiological secretions of insulin by the pancreas into the portal vein which then drains into the liver. In healthy, non-diabetic individuals, pancreatic secretions of insulin correspond to the intake of food. The pancreas will secrete variable amounts of insulin based upon the amount of food consumed among other factors. Continuous exposure to insulin and glucagon is known to decrease the hormones’ metabolic effectiveness on glucose production in humans due to the body developing an increased tolerance to the hormones. Down-regulation at the cellular level may partially explain the decreased action of steady-state levels of insulin, while pulsatile hormone secretion may allow recovery of receptor affinity and numbers for insulin. Intermittent intravenous insulin administration with peaks of insulin concentrations may enhance suppression of gluconeogenesis and reduce hepatic glucose production.

Thad is a masculine given name, often a short form (hypocorism) of Thaddeus. It may refer to:

Liver failure

Liver failure or hepatic insufficiency is the inability of the liver to perform its normal synthetic and metabolic function as part of normal physiology. Two forms are recognised, acute and chronic. Recently a third form of liver failure known as acute-on-chronic liver failure (ACLF) is increasingly being recognized.

Tropisetron chemical compound used to treat nausea and vomiting following chemotherapy

Tropisetron is a serotonin 5-HT3 receptor antagonist used mainly as an antiemetic to treat nausea and vomiting following chemotherapy, although it has been used experimentally as an analgesic in cases of fibromyalgia.

Hepatic lipase protein-coding gene in the species Homo sapiens

Hepatic lipase (HL), also called hepatic triglyceride lipase (HTGL) or LIPC, is a form of lipase, catalyzing the hydrolysis of triacylglyceride. Hepatic lipase is coded by chromosome 15 and its gene is also often referred to as HTGL or LIPC. Hepatic lipase is expressed mainly in liver cells, known as hepatocytes, and endothelial cells of the liver. The hepatic lipase can either remain attached to the liver or can unbind from the liver endothelial cells and is free to enter the body’s circulation system. When bound on the endothelial cells of the liver, it is often found bound to HSPG, heparan sulfate proteoglycans (HSPG), keeping HL inactive and unable to bind to HDL or IDL. When it is free in the bloodstream, however, it is found associated with HDL to maintain it inactive. This is because the triacylglycerides in HDL serve as a substrate, but the lipoprotein contains proteins around the triacylglycerides that can prevent the triacylglycerides from being broken down by HL.

Portal venous pressure is the blood pressure in the hepatic portal vein, and is normally between 5-10 mmHg. Raised portal venous pressure is termed portal hypertension, and has numerous sequelae such as ascites and hepatic encephalopathy.

HU-308 chemical compound

HU-308 is a drug that acts as a cannabinoid agonist. It is highly selective for the CB2 receptor subtype, with a selectivity of over 5000x for CB2 vs CB1. The synthesis and characterization took place in the laboratory of Prof. Mechoulam at the Hebrew University of Jerusalem in the late 1990s. It has analgesic effects, promotes proliferation of neural stem cells, and protects both liver and blood vessel tissues against oxidative stress via inhibition of TNF-α.

<i>Capillaria hepatica</i> species of worm

Capillaria hepatica is a parasitic nematode which causes hepatic capillariasis in rodents and numerous other mammal species, including humans. The life cycle of C. hepatica may be completed in a single host species. However, the eggs, which are laid in the liver, must mature outside of the host body prior to infecting a new host. So the death of the host in which the adults reach sexual maturity, either by being eaten or dying and decomposing, is necessary for completion of the life cycle.

Cirrhosis long-term disease of the liver

Cirrhosis is a condition in which the liver does not function properly due to long-term damage. This damage is characterized by the replacement of normal liver tissue by scar tissue. Typically, the disease develops slowly over months or years. Early on, there are often no symptoms. As the disease worsens, a person may become tired, weak, itchy, have swelling in the lower legs, develop yellow skin, bruise easily, have fluid build up in the abdomen, or develop spider-like blood vessels on the skin. The fluid build-up in the abdomen may become spontaneously infected. Other serious complications include hepatic encephalopathy, bleeding from dilated veins in the esophagus or dilated stomach veins, and liver cancer. Hepatic encephalopathy results in confusion and may lead to unconsciousness.

Computed tomography of the abdomen and pelvis

Computed tomography of the abdomen and pelvis is an application of computed tomography (CT) and is a sensitive method for diagnosis of abdominal diseases. It is used frequently to determine stage of cancer and to follow progress. It is also a useful test to investigate acute abdominal pain. Renal stones, appendicitis, pancreatitis, diverticulitis, abdominal aortic aneurysm, and bowel obstruction are conditions that are readily diagnosed and assessed with CT. CT is also the first line for detecting solid organ injury after trauma.

References

  1. Dr. Sanjay M. Khaladkar, Dr. Vidhi Bakshi, Dr. Rajul Bhargava and Dr. V. M. Kulkarni (2016-08-20). "Pseudolesion (THAD) of Liver and Target Sign in hepatic abscess on MDCT" (PDF). International Journal of Current Research. 8 (8).CS1 maint: Multiple names: authors list (link) (Creative Commons Attribution License)
  2. Yves Leonard Voss and Dr Yuranga Weerakkody. "Transient hepatic attenuation differences". Radiopaedia . Retrieved 2018-01-25.