Что (кто) такое MRI$95394$ - определение
Википедия
Fast low angle shot magnetic resonance imaging (FLASH MRI) is a particular sequence of magnetic resonance imaging. It is a gradient echo sequence which combines a low-flip angle radio-frequency excitation of the nuclear magnetic resonance signal (recorded as a spatially encoded gradient echo) with a short repetition time. It is the generic form of steady-state free precession imaging.
Different manufacturers of MRI equipment use different names for this experiment. Siemens uses the name FLASH, General Electric used the name SPGR (Spoiled Gradient Echo), and Philips uses the name CE-FFE-T1 (Contrast-Enhanced Fast Field Echo) or T1-FFE.
Depending on the desired contrast, the generic FLASH technique provides spoiled versions that destroy transverse coherences and yield T1 contrast as well as refocused versions (constant phase per repetition) and fully balanced versions (zero phase per repetition) that incorporate transverse coherences into the steady-state signal and offer T1/T2 contrast.
Applications include:
- cross-sectional images with acquisition times of a few seconds enable MRI studies of the thorax and abdomen within a single breathhold,
- dynamic acquisitions synchronized to the electrocardiogram generate movies of the beating heart,
- sequential acquisitions monitor physiological processes such as the differential uptake of contrast media into body tissues,
- three-dimensional acquisitions visualize complex anatomic structures (brain, joints) at unprecedented high spatial resolution in all three dimensions and along arbitrary view directions, and
- Magnetic resonance angiography (MRA) yields three-dimensional representations of the vasculature.
