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Fluid-attenuated inversion recovery (FLAIR) is a magnetic resonance imaging sequence with an inversion recovery set to null fluids. For example, it can be used in brain imaging to suppress cerebrospinal fluid (CSF) effects on the image, so as to bring out the periventricular hyperintense lesions, such as multiple sclerosis (MS) plaques. [ 1 ]
In diffusion weighted imaging (DWI), the intensity of each image element reflects the best estimate of the rate of water diffusion at that location.Because the mobility of water is driven by thermal agitation and highly dependent on its cellular environment, the hypothesis behind DWI is that findings may indicate (early) pathologic change.
Diffuse axonal injury after a motorcycle accident. MRI after 3 days: on T1-weighted images the injury is barely visible. On the FLAIR, DWI and T2*-weighted images a small bleed is identifiable. DAI is difficult to detect since it does not show up well on CT scans or with other macroscopic imaging techniques, though it shows up microscopically. [9]
Diffusion-weighted images (DWI): DWI uses the diffusion of water molecules to generate contrast in MR images. Proton density (PD) images: CSF has a relatively high level of protons, making CSF appear bright. Gray matter is brighter than white matter. [27] False color MRI by applying red to T1, green to PD and blue to T2.
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields , magnetic field gradients, and radio waves to form images of the organs in the body.
Images of CAA collected at 1.5 T. Left, conventional T2* (TE=20 ms), center, SWI processed magnitude image (TE=40 ms) and right, SWI phase image (TE=40 ms) Gradient recalled echo (GRE) imaging is the conventional way to detect hemorrhage in CAA , however SWI is a much more sensitive technique that can reveal many micro-hemorrhages that are ...
A magnetic resonance imaging instrument (MRI scanner), or "nuclear magnetic resonance imaging" scanner as it was originally known, uses powerful magnets to polarize and excite hydrogen nuclei (i.e., single protons) of water molecules in human tissue, producing a detectable signal which is spatially encoded, resulting in images of the body. [5]
An MRI pulse sequence in magnetic resonance imaging (MRI) is a particular setting of pulse sequences and pulsed field gradients, resulting in a particular image appearance. [ 1 ] A multiparametric MRI is a combination of two or more sequences, and/or including other specialized MRI configurations such as spectroscopy .