Selasa, 26 Mei 2009

ABOUT ARTIFACT MRI

Aliasing, wrap around, back folding, fold over artifact
Charasteristics

Appearance of a part of anatomy outside the FOV in the opposite side which always acoour at the edge of image in phase-encoding direction.

Artifact reduction
1.enlarge FOV or RFOV until covers region of interest
2.Place rest slab on anatomy which is outside FOV
3.Change fold-over direction
4.Use fold-over suppresion = yes


Sense artifact

Characteristic
Appearance of a part of anatomy outside the FOV in the opposite side which always occur in the middle of the image in phase-encoding direction.


artifact reduction :
1.Reduce SENSE factore
2.Switch off sense
3.Change fold over direction
4.Enlarge FOVb

How to increase signal
1.Increase NSA side effect scan time increase
2.Reduce Matrix scan side effect image blur
3.Increase thickness side effect partial volume
4.Increase FOv side effect scan time increase
5.Increase TR side effect scan time increase

Blur image
How to increase sharpness
1.Increase matrix scan
2.Thinner slice in 3D technique

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