What is metal artifact reduction sequence?
What is metal artifact reduction sequence?
A metal artifact reduction sequence (MARS) is intended to reduce the size and intensity of susceptibility artifacts resulting from magnetic field distortion.
How can the metal susceptibility artifact be reduced?
Examples are 1:
- lower magnetic field strength: 1.5 T rather than 3 T.
- increase bandwidth during slice selection and readout.
- increase matrix: 512 pixel.
- maintain good signal to noise ratio by increasing number of excitations (NEX)
- spin echo instead of gradient echo where possible.
How do you stop metal artifacts?
It is known that metal artifacts can be reduced by modifying standard acquisition and reconstruction, by modifying projection data and/or image data and by using virtual monochromatic imaging extracted from dual-energy CT.
How does MRI reduce flow artifact?
Gradient moment nulling (GMN) is an effective method for eliminating flow artifacts in gradient echo images, while presaturation is more applicable to the same task in spin echo acquisitions.
What does Mars stand for in MRI?
Background and purpose. Metal artifact reduction sequence (MARS) MRI and ultrasound scanning (USS) can both be used to detect pseudotumors, abductor muscle atrophy, and tendinous pathology in patients with painful metal-on-metal (MOM) hip arthroplasty.
What is metal artifact in MRI?
Conclusion: The presence of metallic implants in MRI can cause substantial image artifacts, including signal loss, failure of fat suppression, geometric distortion, and bright pile-up artifacts. These cause large resonant frequency changes and failure of many MRI mechanisms.
How do you lower the beam hardening artifact?
Beam hardening reduction Streak artifacts can sometimes effectively be reduced by increasing tube voltage (better penetration of high-density objects), or by using a dual-energy imaging approach.
How can MRI artifacts be reduced?
Basic methods to reduce metallic artifacts include use of spin-echo or fast spin-echo sequences with long echo train lengths, short inversion time inversion-recovery (STIR) sequences for fat suppression, a high bandwidth, thin section selection, and an increased matrix.
How do you reduce motion artifacts in MRI?
Reducing Motion Artifacts
- Minimize the degree of motion. a. The importance of simple instruction/education of the patient to hold still while the scanner is making noise should not be underestimated.
- Suppress signal from moving tissues. a.
- Adjust imaging sequences and parameters. a.
- Detect and compensate for motion.
What is metal artifact reduction?
A metal artifact reduction sequence (MARS) is intended to reduce the size and intensity of susceptibility artifacts resulting from magnetic field distortion.
What is an artifact on MRI?
Patient motion – intentional or not – cause artifacts on the MRI image. Motion artifacts typically show up as blurring or ghosting, especially in the phase-encoding direction. Recognizing that these ghost images are due to motion can help radiologists diagnose patients more accurately.
What is metal reduction?
The reduction of metals was originally understood to be the reactions used to obtain metals from their oxides by using substances having greater affinity for oxygen than the metal.
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