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Using contrast injected into the blood vessels, images are created to look for blockages, aneurysms (dilations of walls), dissections (tearing of walls), and stenosis (narrowing of vessel). CTA can be used to visualize the vessels of the heart, the aorta and other large blood vessels, the lungs, the kidneys, the head and neck, and the arms and ...
Magnetic resonance angiography (MRA) is a group of techniques based on magnetic resonance imaging (MRI) to image blood vessels. Magnetic resonance angiography is used to generate images of arteries (and less commonly veins) in order to evaluate them for stenosis (abnormal narrowing), occlusions, aneurysms (vessel wall dilatations, at risk of rupture) or other abnormalities.
[3] [4] Another type of treatment possible by angiography (if the images reveal an aneurysm) is the introduction of metal coils through the catheter already in place and maneuvered to the site of aneurysm; over time these coils encourage formation of connective tissue at the site, strengthening the vessel walls.
On CTPA, the pulmonary vessels are filled with contrast, and appear white. Any mass filling defects ( embolus or other matter such as fat ) appears darker. Ideally, the scan should be complete before the contrast reaches the left side of the heart and the aorta , as this may mean contrast has drained from the pulmonary arteries, or require a ...
While bile is made in the liver and stored in the gallbladder, the bile eventually passes into the GI tract through the hepatic, cystic and common bile ducts. Any condition that prevents the normal flow of bile from the liver, through these bile vessels and into the GI tract can cause a condition called jaundice. [citation needed]
Digital subtraction angiography (DSA) is a fluoroscopy technique used in interventional radiology to clearly visualize blood vessels in a bony or dense soft tissue environment. Images are produced using contrast medium by subtracting a "pre-contrast image" or mask from subsequent images, once the contrast medium has been introduced into a ...
Bolus tracking is a technique to optimize timing of the imaging. A small bolus of radio-opaque contrast media is injected into a patient via a peripheral intravenous cannula . Depending on the vessel being imaged, the volume of contrast is tracked using a region of interest (abbreviated "R.O.I.") at a certain level and then followed by the CT ...
Aneurysm means an outpouching of a blood vessel wall that is filled with blood. Aneurysms occur at a point of weakness in the vessel wall. This can be because of acquired disease or hereditary factors. The repeated trauma of blood flow against the vessel wall presses against the point of weakness and causes the aneurysm to enlarge. [20]