MRI Artifacts This presentation is available at: Zhuo, J. et al. Radiographics 2006;26:275-297, AAPM/RSNA.

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Presentation transcript:

MRI Artifacts This presentation is available at: Zhuo, J. et al. Radiographics 2006;26: , AAPM/RSNA Physics Tutorial for Residents: MRI Artifacts, Safety and Quality Control

Figure 20. Aliasing artifact caused by phase errors at both sides of the magnet. Image shows a moiré artifact produced by the addition and cancellation of signals. Copyright ©Radiological Society of North America, 2006 Zhuo, J. et al. Radiographics 2006;26:

Figure 19a. Aliasing artifact caused by imaging with too small a field of view. Image shows aliasing artifact. Copyright ©Radiological Society of North America, 2006 Zhuo, J. et al. Radiographics 2006;26:

Figure 19b. Aliasing artifact caused by imaging with too small a field of view. Image obtained with the phase encoding and frequency encoding axes exchanged shows no aliasing. Copyright ©Radiological Society of North America, 2006 Zhuo, J. et al. Radiographics 2006;26:

Figure 7a. Motion-related artifacts. Abdominal image obtained without breath hold shows breathing-related motion artifacts. Copyright ©Radiological Society of North America, 2006 Zhuo, J. et al. Radiographics 2006;26:

Figure 7b. Motion-related artifacts. Abdominal image obtained with breath hold shows a minimal artifact due to respiration and several motion artifacts due to cardiac pulsation. Copyright ©Radiological Society of North America, 2006 Zhuo, J. et al. Radiographics 2006;26:

Figure 11a. Control of flow-related artifacts. (a) Image shows a cardiac pulsation artifact. (b, c) Images obtained with a saturation band superior to the imaging section (b) and with first-order motion compensation (c) show less severe flow-related artifacts. Copyright ©Radiological Society of North America, 2006 Zhuo, J. et al. Radiographics 2006;26: (a)

Figure 11b. Control of flow-related artifacts. (a) Image shows a cardiac pulsation artifact. (b, c) Images obtained with a saturation band superior to the imaging section (b) and with first-order motion compensation (c) show less severe flow-related artifacts. Copyright ©Radiological Society of North America, 2006 Zhuo, J. et al. Radiographics 2006;26: (b)

Figure 11c. Control of flow-related artifacts. (a) Image shows a cardiac pulsation artifact. (b, c) Images obtained with a saturation band superior to the imaging section (b) and with first-order motion compensation (c) show less severe flow-related artifacts. Copyright ©Radiological Society of North America, 2006 Zhuo, J. et al. Radiographics 2006;26: (c)

Figure 13a. Echo-planar images show magnetic susceptibility artifacts. Left-right phase encoding causes severe distortion of the signal (arrows). Copyright ©Radiological Society of North America, 2006 Zhuo, J. et al. Radiographics 2006;26:

Figure 14. Sagittal MR image shows a magnetic susceptibility artifact that resulted from the presence of metallic dental fillings Copyright ©Radiological Society of North America, 2006 Zhuo, J. et al. Radiographics 2006;26:

Figure 15a. Chemical shift artifact at echo-planar imaging. Image shows severe chemical shift artifact from insufficient fat suppression. Copyright ©Radiological Society of North America, 2006 Zhuo, J. et al. Radiographics 2006;26:

Copyright ©Radiological Society of North America, 2006 Figure 15b. Chemical shift artifact at echo-planar imaging. Image obtained with fat saturation shows minimization of the chemical shift artifact or off-resonance effect. Copyright ©Radiological Society of North America, 2006 Zhuo, J. et al. Radiographics 2006;26:

Copyright ©Radiological Society of North America, 2006 Zhuo, J. et al. Radiographics 2006;26: Figure 5a. Spike artifact. Bad data points in k-space (arrow in b) result in band artifacts on the MR image in a. The location of the bad data points, and their distance from the center of k-space, determine the angulation of the bands and the distance between them. The intensity of the spike determines the severity of the artifact.

Figure 5b. Spike artifact. Bad data points in k-space (arrow in b) result in band artifacts on the MR image in a. The location of the bad data points, and their distance from the center of k-space, determine the angulation of the bands and the distance between them. The intensity of the spike determines the severity of the artifact. Copyright ©Radiological Society of North America, 2006 Zhuo, J. et al. Radiographics 2006;26: