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The comb sign is characterized by the appearance of dilated, prominent vessels in the mesentery of the abdomen, which appears similar to the teeth of a comb. These engorged vessels result from inflammation and increased blood flow in the mesenteric vessels, which is a common response to acute or chronic inflammatory conditions in the gastrointestinal tract.
Flow-mediated dilation (FMD) refers to dilation (widening) of an artery when blood flow increases in that artery. [1] [2] The primary cause of FMD is release of nitric oxide by endothelial cells. [1] To determine FMD, brachial artery dilation following a transient period of forearm ischemia is measured using ultrasound. [3]
While healthy livers are predominantly oxygenated by portal blood supply, long-standing portal hypertension results in compensatory hypertrophy of and increased reliance on the hepatic artery for oxygenation. Thus, in people with advanced liver disease the shunting of portal blood away from hepatocytes is usually well tolerated.
Mean arterial pressure (MAP)is a weighted average of systolic and diastolic blood pressures, and is a better measurement of perfusion over the duration of the cardiac cycle. [16] Vasodilation works to decrease vascular resistance and blood pressure through relaxation of smooth muscle cells in the tunica media layer of large arteries and smaller ...
The blood leaves the liver to the heart in the hepatic veins. The portal vein is not a true vein , because it conducts blood to capillary beds in the liver and not directly to the heart. It is a major component of the hepatic portal system , one of three portal venous systems in the human body; the others being the hypophyseal and renal portal ...
The double duct sign is a radiological finding characterized by the simultaneous dilation of the common bile duct and the main pancreatic duct.This sign is significant because it often indicates an obstruction in the distal bile duct and pancreatic duct, frequently caused by serious underlying pathologies such as pancreatic carcinoma or periampullary tumors. [1]
It is determined by wedging a catheter in a hepatic vein, to occlude it, and then measuring the pressure of proximal static blood (which is reflective of pressure in the sinusoids). WHVP in fact slightly underestimates portal pressure due to sinusoidal equilibration in patients without cirrhosis , but the difference between the two is ...
This change occurs in order to match up the tissue's oxygen demand with the actual oxygen supply available in the blood as closely as possible. [1] For example, if a muscle is being utilized actively, it will require more oxygen than it was at rest, so the blood vessels supplying that muscle will vasodilate, or widen in size, to increase the ...