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Digital Subtraction Angiography
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 structure. Hence the term "digital ''subtraction'' angiography. Subtraction angiography was first described in 1935 and in English sources in 1962 as a manual technique. Digital technology made DSA practical starting in the 1970s. Procedure DSA and fluoroscopy In traditional angiography, images are acquired by exposing an area of interest with time-controlled x-rays while injecting a contrast medium into the blood vessels. The image obtained includes the blood vessels, together with all overlying and underlying structures. The images are useful for determining anatomical position and variations, but unhelpful for visualizing blood vessels acc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebral Angiography
Cerebral angiography is a form of angiography which provides images of blood vessels in and around the brain, thereby allowing detection of abnormalities such as arteriovenous malformations and aneurysms. It was pioneered in 1927 by the Portuguese neurologist Egas Moniz at the University of Lisbon, who also helped develop thorotrast for use in the procedure. Typically a catheter is inserted into a large artery (such as the femoral artery) and threaded through the circulatory system to the carotid artery, where a contrast agent is injected. A series of radiographs are taken as the contrast agent spreads through the brain's arterial system, then a second series as it reaches the venous system. For some applications cerebral angiography may yield better images than less invasive methods such as computed tomography angiography and magnetic resonance angiography. In addition, cerebral angiography allows certain treatments to be performed immediately, based on its findings. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carotid Artery Stenosis
Carotid artery stenosis is a narrowing or constriction of any part of the carotid arteries, usually caused by atherosclerosis. Signs and symptoms The common carotid artery is the large artery whose pulse can be felt on both sides of the neck under the jaw. On the right side it starts from the brachiocephalic artery (a branch of the aorta), and on the left side the artery comes directly off the aortic arch. At the throat it forks into the internal carotid artery and the external carotid artery. The internal carotid artery supplies the brain, and the external carotid artery supplies the face. This fork is a common site for atherosclerosis, an inflammatory build-up of atheromatous plaque inside the common carotid artery, or the internal carotid arteries that causes them to narrow. The plaque can be stable and asymptomatic, or it can be a source of embolization. Emboli break off from the plaque and travel through the circulation to blood vessels in the brain. As the vessels get ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peripheral Artery Disease
Peripheral artery disease (PAD) is an abnormal narrowing of arteries other than those that supply the heart or brain. When narrowing occurs in the heart, it is called coronary artery disease, and in the brain, it is called cerebrovascular disease. Peripheral artery disease most commonly affects the legs, but other arteries may also be involved – such as those of the arms, neck, or kidneys. The classic symptom is leg pain when walking which resolves with rest, known as intermittent claudication. Other symptoms include skin ulcers, bluish skin, cold skin, or abnormal nail and hair growth in the affected leg. Complications may include an infection or tissue death which may require amputation; coronary artery disease, or stroke. Up to 50% of people with PAD do not have symptoms. The greatest risk factor for PAD is cigarette smoking. Other risk factors include diabetes, high blood pressure, kidney problems, and high blood cholesterol. The most common underlying mechanism ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contrast Medium
A contrast agent (or contrast medium) is a substance used to increase the contrast of structures or fluids within the body in medical imaging. Contrast agents absorb or alter external electromagnetism or ultrasound, which is different from radiopharmaceuticals, which emit radiation themselves. In x-rays, contrast agents enhance the radiodensity in a target tissue or structure. In MRIs, contrast agents shorten (or in some instances increase) the relaxation times of nuclei within body tissues in order to alter the contrast in the image. Contrast agents are commonly used to improve the visibility of blood vessels and the gastrointestinal tract. Several types of contrast agent are in use in medical imaging and they can roughly be classified based on the imaging modalities where they are used. Most common contrast agents work based on X-ray attenuation and magnetic resonance signal enhancement. Radiocontrast media For radiography, which is based on X-rays, iodine and barium are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computed Tomography Angiography
Computed tomography angiography (also called CT angiography or CTA) is a computed tomography technique used for angiography—the visualization of arteries and veins—throughout the human body. 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 legs. CTA can also be used to localise arterial or venous bleed of the gastrointestinal system. Medical uses CTA can be used to examine blood vessels in many key areas of the body including the brain, kidneys, pelvis, and the lungs. Coronary CT angiography Coronary CT angiography (CCTA) is the use of CT angiography to assess the arteries of the heart. The patient receives an intravenous injection of contrast and then the heart is scanned us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angiography
Angiography or arteriography is a medical imaging technique used to visualize the inside, or lumen, of blood vessels and organs of the body, with particular interest in the arteries, veins, and the heart chambers. Modern angiography is performed by injecting a radio-opaque contrast agent into the blood vessel and imaging using X-ray based techniques such as fluoroscopy. The word itself comes from the Greek words ἀγγεῖον ''angeion'' 'vessel' and γράφειν ''graphein'' 'to write, record'. The film or image of the blood vessels is called an ''angiograph'', or more commonly an ''angiogram''. Though the word can describe both an arteriogram and a venogram, in everyday usage the terms angiogram and arteriogram are often used synonymously, whereas the term venogram is used more precisely. The term angiography has been applied to radionuclide angiography and newer vascular imaging techniques such as CO2 angiography, CT angiography and MR angiography. The term ''iso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nephrotoxic
Nephrotoxicity is toxicity in the kidneys. It is a poisonous effect of some substances, both toxic chemicals and medications, on kidney function. There are various forms, and some drugs may affect kidney function in more than one way. Nephrotoxins are substances displaying nephrotoxicity. Nephrotoxicity should not be confused with some medications predominantly excreted by the kidneys needing their dose adjusted for the decreased kidney function (e.g., heparin, lithium). Types of toxicity Cardiovascular * General: diuretics, β-blockers, vasodilator agents * Local: ACE inhibitors, ciclosporin, tacrolimus. Direct tubular effect * Proximal convoluted tubule: Aminoglycoside antibiotics (e.g., gentamicin), amphotericin B, cisplatin, radiocontrast media, immunoglobulins, mannitol * Distal tubule: NSAIDs (e.g. aspirin, ibuprofen, diclofenac), ACE inhibitors, ciclosporin, lithium salts, cyclophosphamide, amphotericin B * Tubular obstruction: sulphonamides, methotrexate, aciclo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Resonance Angiography
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. MRA is often used to evaluate the arteries of the neck and brain, the thoracic and abdominal aorta, the renal arteries, and the legs (the latter exam is often referred to as a "run-off"). Acquisition A variety of techniques can be used to generate the pictures of blood vessels, both arteries and veins, based on flow effects or on contrast (inherent or pharmacologically generated). The most frequently applied MRA methods involve the use intravenous contrast agents, particularly those containing gadolinium to shorten the ''T''1 of blood to about 250 ms, shorter than the ''T''1 of all other tissues (except f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computed Tomography Angiography
Computed tomography angiography (also called CT angiography or CTA) is a computed tomography technique used for angiography—the visualization of arteries and veins—throughout the human body. 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 legs. CTA can also be used to localise arterial or venous bleed of the gastrointestinal system. Medical uses CTA can be used to examine blood vessels in many key areas of the body including the brain, kidneys, pelvis, and the lungs. Coronary CT angiography Coronary CT angiography (CCTA) is the use of CT angiography to assess the arteries of the heart. The patient receives an intravenous injection of contrast and then the heart is scanned us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arteriovenous Malformation
Arteriovenous malformation is an abnormal connection between arteries and veins, bypassing the capillary system. This vascular anomaly is widely known because of its occurrence in the central nervous system (usually cerebral AVM), but can appear in any location. Although many AVMs are asymptomatic, they can cause intense pain or bleeding or lead to other serious medical problems. AVMs are usually congenital and belong to the RASopathies. The genetic transmission patterns of AVMs are incomplete, but there are known genetic mutations (for instance in the epithelial line, tumor suppressor PTEN gene) which can lead to an increased occurrence throughout the body. Signs and symptoms Symptoms of AVM vary according to the location of the malformation. Roughly 88% of people with an AVM are asymptomatic; often the malformation is discovered as part of an autopsy or during treatment of an unrelated disorder (called in medicine an "incidental finding"); in rare cases, its expansion or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebral Aneurysm
An intracranial aneurysm, also known as a brain aneurysm, is a cerebrovascular disorder in which weakness in the wall of a cerebral artery or vein causes a localized dilation or ballooning of the blood vessel. Aneurysms in the posterior circulation (basilar artery, vertebral arteries and posterior communicating artery) have a higher risk of rupture. Basilar artery aneurysms represent only 3–5% of all intracranial aneurysms but are the most common aneurysms in the posterior circulation. Classification Cerebral aneurysms are classified both by size and shape. Small aneurysms have a diameter of less than 15 mm. Larger aneurysms include those classified as large (15 to 25 mm), giant (25 to 50 mm), and super-giant (over 50 mm). Berry (saccular) aneurysms Saccular aneurysms, also known as berry aneurysms, appear as a round outpouching and are the most common form of cerebral aneurysm. Causes include connective tissue disorders, polycystic kidney disease, ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wiley-Blackwell
Wiley-Blackwell is an international scientific, technical, medical, and scholarly publishing business of John Wiley & Sons. It was formed by the merger of John Wiley & Sons Global Scientific, Technical, and Medical business with Blackwell Publishing in 2007.About Wiley-Blackwell John Wiley & Sons, Inc. Wiley-Blackwell is now an imprint that publishes a diverse range of academic and professional fields, including , , , |
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