Hi all there!
@Peter Kochunov <[log in to unmask]>:
I call it a vibration artifact because we thought that this is one
possibility:
When I am in the scanner I feel that the vibrations are on my occiput
exactly at those directions that are affected (remember only x
gradient!).
It is a Magnetom Trio TIM system. And we used the 30dir_2x2x2mm
sequence and the wip_30dir_2x2x2mm sequence from Siemens. There is no
difference between both sequences. Both of them show the same artifact.
@Andreas Bartsch <[log in to unmask]>:
@Mikolaj Pawlak <[log in to unmask]>:
Thanks! At least one who saw it!
In our clinic routine they have it also. But they explained it with
patients moving…
I met that artifact because, coming from fMRI, we where constantly
using the polystyrene-balls-vacuum-cushion and in every of 7 subjects
I got the same artifact in the same directions (x). Thus I think I
reproduce it quite constantly ;-)
Changing the cushion to the Siemens foam cushion made the reproduction
less reliable, i.e. sometimes it is there, sometimes not.
My current explanation is that the x direction is the less stables as
well as for the patient supine as for the scanner bed and that the
x-gradient vibrations, depending on the subjects weight and size, give
resonance to the head which might cause this artifact.
We use a 12-channel receive-only coil.
What would you suggest to do in oder "to go into"?
Thanks for your help
Markus
--
Dr. med. Markus Gschwind, M.D.
Laboratory for Neurology and Imaging of Cognition
Dept of Neurosciences
University Medical Center (CMU)
1 Michel-Servet - 1211 GENEVA - CH
Tel 0041 (0) 22 379 5324
Fax 0041 (0) 22 379 5402
email: [log in to unmask]
http://labnic.unige.ch
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