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Blood Pool Agents
Blood pool agents (BPAs) are a class of magnetic resonance angiography contrast agents. Blood pool agents (also known as intravascular contrast agents) are differentiated from other contrast agents due to their high molecular weight and higher relaxivities. Their large size prevents diffusion through the vascular epithelium and leakage into the interstitial space, and because of this they stay in the vascular system for a longer time period. Most contrast agents, leave the vascular system within a few minutes, however blood pool agents remain in the circulation for up to an hour, extending the window available for imaging. Longer image acquisition times allow better signal-to-noise ratio and improved image resolution. Roles of blood pool agents Due to their extended time in the circulatory system, blood pool agents can be used for delayed steady-state imaging, and additionally these results can be combined with first pass arterial imaging. Classes of blood pool agents Albumi ... [...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), Vascular occlusion, 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 artery, arteries and veins, based on flow effects or on contrast (inherent or pharmacologically generated). The most frequently applied MRA methods involve the use intravenous MRI contrast agent, contrast agents, particularly those containing gadolinium to shorten the Spin–lattice relaxation, ''T''1 of bloo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
