Acquisition
A variety of techniques can be used to generate the pictures, based on flow effects or on contrast (inherent or pharmacologically generated). These images, unlike conventional or CT angiography do not display the lumen of the vessel, but rather the blood flowing through the vessel. The most popular methods now use intravenous contrast agents (Gadolinium-DTPA) to shorten the T1 of blood to about 250 ms, shorter than the T1 of all other tissues (save fat). Short-TR sequences produce bright images of the blood. However, many techniques exist, that can actually be classified into two groups: Flow-dependent and Flow-independent methods.
Read more about this topic: Magnetic Resonance Angiography
Famous quotes containing the word acquisition:
“Whatever may be our just grievances in the southern states, it is fitting that we acknowledge that, considering their poverty and past relationship to the Negro race, they have done remarkably well for the cause of education among us. That the whole South should commit itself to the principle that the colored people have a right to be educated is an immense acquisition to the cause of popular education.”
—Fannie Barrier Williams (1855–1944)
“Wars and revolutions and battles are due simply and solely to the body and its desires. All wars are undertaken for the acquisition of wealth; and the reason why we have to acquire wealth is the body, because we are slaves in its service.”
—Socrates (469–399 B.C.)
“Always and everywhere children take an active role in the construction and acquisition of learning and understanding. To learn is a satisfying experience, but also, as the psychologist Nelson Goodman tells us, to understand is to experience desire, drama, and conquest.”
—Carolyn Edwards (20th century)