The document discusses MRI image artifacts, which are distortions in MRI images caused by various factors like patient movement and hardware limitations, and emphasizes the importance of managing them for accurate diagnoses. It outlines common types of artifacts such as motion, susceptibility, chemical shift, and zipper artifacts, along with their causes and potential remedies. Recommendations include using faster imaging techniques, increasing receiver bandwidth, and ensuring proper RF shielding to improve image quality.

1. MRI Image Artifacts and Their
Remedies
Presenter: Dr. Dheeraj Kumar
MRIT, Ph.D. (Radiology and Imaging)
Assistant Professor
Medical Radiology and Imaging Technology
School of Health Sciences, CSJM University, Kanpur

2. MRI Image Artifacts: Definition
• MRI Image Artifacts are distortions or errors in the MRI images that do not
represent the true anatomy or pathology of the subject being imaged.
• These artifacts can be caused by a variety of factors including patient
movement, hardware limitations, specific properties of the tissues being
imaged, and the parameters set during the scanning process.
• Understanding and managing these artifacts is crucial for accurate
diagnosis and treatment planning.
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3. Types of MRI Artifacts
• Common Types of MRI Artifacts
Content:
• Motion Artifacts
• Susceptibility Artifacts
• Chemical Shift Artifacts
• Aliasing (Wrap-Around) Artifacts
• Gibbs (Ringing) Artifacts
• Truncation Artifacts
• Ghosting Artifacts
• Zebra Artifacts
• Zipper Artifacts
MRI Image Artifacts and Their Remedies By- Dheeraj Kumar 3

4. Motion Artifacts
Blurring or ghosting due to patient
movement.
• Causes: Voluntary or involuntary patient
movement, respiration, cardiac motion.
• Remedies:
• Use of faster imaging sequences
• Patient immobilization
• Breath-hold techniques
• Motion correction algorithms
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5. Susceptibility Artifacts
Distortion or signal loss at tissue interfaces
with different magnetic susceptibilities.
• Causes: Metal implants, air-tissue
interfaces.
• Remedies:
• Use of spin-echo sequences
• Decrease echo time (TE)
• Remove metal objects if possible
• Use of higher bandwidth
MRI Image Artifacts and Their Remedies By- Dheeraj Kumar 5

6. Chemical Shift Artifacts
Misregistration of fat and water
signals.
• Causes: Difference in precessional
frequencies of fat and water.
• Remedies:
• Increase receiver bandwidth
• Use fat suppression techniques
• Adjust echo time (TE)
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7. Aliasing (Wrap-Around) Artifacts
Signal from outside the field of view
(FOV) folds into the image.
• Causes: Inadequate FOV.
• Remedies:
• Increase FOV
• Use anti-aliasing techniques
• Apply presaturation bands
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8. Gibbs (Ringing) Artifacts
Oscillations at sharp boundaries.
• Causes: Finite sampling of high-
frequency data.
• Remedies:
• Increase matrix size
• Use of filtering techniques
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9. Truncation Artifacts
False bands or lines parallel to edges.
• Causes: Inadequate data sampling.
• Remedies:
• Increase number of phase encoding steps
• Apply apodization filters
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10. Ghosting Artifacts
Replicated images or echoes.
• Causes: Periodic motion,
gradient imperfections.
• Remedies:
• Synchronize imaging with the
patient's physiology (gating)
• Use of navigator echoes
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11. Zebra Artifacts
Alternating dark and bright
lines.
• Causes: Gradient nonlinearity.
• Remedies:
• Use of gradient shimming
• Ensure proper gradient
calibration
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12. Zipper Artifacts
Zipper Artifacts are a type of MRI artifact characterized by linear, zipper-like lines that appear across the
image. These artifacts can significantly degrade image quality and obscure anatomical details.
Causes
• Radiofrequency (RF) Interference: External RF signals infiltrate the MRI scanner's RF shielding.
• Gradient Malfunctions: Issues with the MRI scanner’s gradient system can introduce periodic noise.
• Improper Shielding: Compromises in the MRI room’s Faraday cage, which is designed to block external
RF interference.
• Loose Connections: Poor connections in the RF coil or cables.
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13. Remedies:
• Ensure Proper RF Shielding
• Check and Secure Connections
• Minimize External RF Sources
• Regular Maintenance of Equipment
• Use of RF Filters
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14. References
• 1. Haacke, E. M., Brown, R. W., Thompson, M. R., & Venkatesan, R. (1999). Magnetic Resonance Imaging:
Physical Principles and Sequence Design. Wiley-Liss.
• 2. McRobbie, D. W., Moore, E. A., Graves, M. J., & Prince, M. R. (2017). MRI from Picture to Proton (3rd
ed.). Cambridge University Press.
• 3. Zhuo, J., & Gullapalli, R. P. (2006). AAPM/RSNA physics tutorial for residents: MR artifacts, safety, and
quality control. Radiographics, 26(1), 275-297. https://doi.org/10.1148/rg.261055138
• 4. Westbrook, C., Roth, C. K., & Talbot, J. (2011). MRI in Practice (4th ed.). Wiley-Blackwell.
• 5. Elster, A. D., & Burdette, J. H. (2001). Questions and Answers in Magnetic Resonance Imaging (2nd ed.).
Mosby.
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15. Thank You
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