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Susceptibility weighted imaging (SWI), originally called BOLD venographic imaging, is an MRI sequence that is exquisitely sensitive to venous blood, hemorrhage and iron storage. SWI uses a fully flow compensated, long echo, gradient recalled echo (GRE) pulse sequence to acquire images.
CONN preprocessing pipeline includes steps designed to estimate and correct effects derived from subject motion within the scanner (realignment), correct spatial distortions due to inhomogeneities in the magnetic field (susceptibility distortion correction), correct for temporal misalignment across slices (slice timing correction), identify potential outlier images within each scanning session ...
A unique advantage of MRI is that it provides not only the phase image but also the magnitude image. In principle, the contrast change, or equivalently the edge, on a magnitude image arises from the underlying change of tissue type, which is the same cause for the change of susceptibility.
Dynamic susceptibility contrast: DSC: Measures changes over time in susceptibility-induced signal loss due to gadolinium contrast injection. [20] Provides measurements of blood flow; In cerebral infarction, the infarcted core and the penumbra have decreased perfusion and delayed contrast arrival (pictured). [21] Arterial spin labelling: ASL
For a real image, the corresponding k-space is conjugate symmetric: the imaginary component at opposite k-space coordinates has the opposite sign.. In magnetic resonance imaging (MRI), the k-space or reciprocal space (a mathematical space of spatial frequencies) is obtained as the 2D or 3D Fourier transform of the image measured.
Phase contrast MRI is one of the main techniques for magnetic resonance angiography (MRA). This 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 FMRIB Software Library, abbreviated FSL, is a software library containing image analysis and statistical tools for functional, structural and diffusion MRI brain imaging data. FSL is available as both precompiled binaries and source code for Apple and PC computers. It is freely available for non-commercial use.
Demonstration of the HARP processing of a tagged cardiac MRI slice. (a) An MR image with vertical SPAMM tags. (b) shows the magnitude of its Fourier transform. By extracting the spectral peak inside the circle, a complex image is produced with a magnitude (c) and a phase (d). A tagged MRI showing motion of a human heart is shown in the image (a).