![]() ![]() Bright or dark lines that are seen parallel & next to borders of abrupt intensity change.At 1.5 Tesla, occurs at 4.5 ms multiples, starting at about 2.3 ms. ![]() Occurs at TE when the fat and water spins located in the same pixel are out of phase, cancelling each other’s signal.An artificially created black line located at fat-water interfaces such as muscle-fat interfaces.Use surface coil so no signal detected outside of FOV.Swapping phase and frequency direction so phase is in the narrower direction.Oversampling the data in the frequency direction (standard) and increasing phase steps in the phase-encoded direction – phase compensation (time or SNR penalty).Increase the FOV (decreases resolution).May occur in end slices of a 3D acquisition.Caused by undersampling in the phase or (rarely) frequency direction.Occurs when the field of view (FOV) is smaller than the body part being imaged causing the region beyond to project on the other side of the image.Worst at higher field strength, less with stronger gradients.Common in vertebral bodies, orbits, solid organs surrounded by fat.The different resonant frequency of fat & water is transformed into spatial difference.Some artifacts can be mitigated by the MR Tech while others require an engineer.Others may be confused with pathology.Some effect the quality of the MRI exam. ![]()
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