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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.
This artifact can be a consequence of environmental factors or the human body (such as blood flow, implants, etc.). 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.
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: Magnetic labeling of arterial blood below the imaging slab, which subsequently enters the region of interest. [22] It does not need gadolinium ...
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.
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 ...
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]
Phase contrast MRI (PC-MRI) is used to measure flow velocities in the body. It is used mainly to measure blood flow in the heart and throughout the body. PC-MRI may be considered a method of magnetic resonance velocimetry. Since modern PC-MRI typically is time-resolved, it also may be referred to as 4-D imaging (three spatial dimensions plus ...
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]