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An MRI artifact is a visual artifact (an anomaly seen during visual representation) in magnetic resonance imaging (MRI). It is a feature appearing in an image that is not present in the original object. [1] Many different artifacts can occur during MRI, some affecting the diagnostic quality, while others may be confused with pathology.
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.
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]
An MRI artifact is a visual artifact, that is, an anomaly during visual representation. Many different artifacts can occur during magnetic resonance imaging (MRI), some affecting the diagnostic quality, while others may be confused with pathology.
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]
For example, if a certain velocity leads to a 361° phase shift, we cannot distinguish this one from a velocity that causes a 1° phase shift. This phenomenon is called aliasing. Because both the forward direction velocity and the backward direction velocity are important, phase angles are usually within the range from −180° to 180°. [5]
Modern 3 Tesla clinical MRI scanner.. Magnetic resonance imaging (MRI) is a medical imaging technique mostly used in radiology and nuclear medicine in order to investigate the anatomy and physiology of the body, and to detect pathologies including tumors, inflammation, neurological conditions such as stroke, disorders of muscles and joints, and abnormalities in the heart and blood vessels ...
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.