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A motion artifact is one of the most common artifacts in MR imaging. [2] Motion can cause either ghost images or diffuse image noise in the phase-encoding direction. The reason for mainly affecting data sampling in the phase-encoding direction is the significant difference in the time of acquisition in the frequency- and phase-encoding ...
Example Spin echo: T1 weighted: T1: Measuring spin–lattice relaxation by using a short repetition time (TR) and echo time (TE). Lower signal for more water content, [1] as in edema, tumor, infarction, inflammation, infection, hyperacute or chronic hemorrhage. [2] High signal for fat [1] [2] High signal for paramagnetic substances, such as MRI ...
Ghosting is a multidimensional artifact that occurs in the MRI in the phase-encoded direction (short axis of the image) after applying the Fourier transform. When the phase of the magnetic resonance signal is being encoded into the 2D or 3D Fourier image, a mild deviation from the actual phase and amplitude may occur.
A variant of diffusion weighted imaging, diffusion spectrum imaging (DSI), [4] was used in deriving the Connectome data sets; DSI is a variant of diffusion-weighted imaging that is sensitive to intra-voxel heterogeneities in diffusion directions caused by crossing fiber tracts and thus allows more accurate mapping of axonal trajectories than ...
The Brain Imaging Data Structure (BIDS) is a standard for organizing, annotating, and describing data collected during neuroimaging experiments. It is based on a formalized file and directory structure and metadata files (based on JSON and TSV ) with controlled vocabulary . [ 1 ]
Displacement artifacts (also known as misregistration and oblique flow artifacts) occur when there is a time difference between the phase and frequency encoding. These artifacts are highest when the flow direction is within the slice plane (most prominent in the heart and aorta for biological flows) [10]
BIRN fMRI and MRI data fMRI, MRI scans and atlases for human and mouse brains Mouse, Human Multilevel: brain regions, connections, neurons, gene expression patterns MRI datasets, fMRI datasets Healthy, Elderly: No Bipolar Disorder Neuroimaging Database Meta-analysis and database of MRI studies Human Macroscopic Descriptive, numerical Bipolar ...
The magic angle artifact refers to the increased signal observed when MRI sequences with short echo time (TE) (e.g., T 1 or proton density spin-echo sequences) are used to image tissues with well-ordered collagen fibers in one direction (e.g., tendon or articular hyaline cartilage). [1]