hmmm, could also be a low sensitivity region if the region around the eyes
doesn't have coil coverage. I would try putting a line of control points in
the white matter going from anterior and moving posteriorly until the
drop-off is not that big (i.e. until the T1.mgz has voxels==110 in the
white matter)
On Tue, 24 Jan 2012, Mahinda
Yogarajah wrote:
Hi,
No problem - thanks for coming back to me.
Imaging was carried out with a GE Excite II 3-T scanner using an eight-
channel phased array coil. We acquired coronal 3D-T1 weighted fast spoiled
gradient echo (FSPGR) (0.94 × 0.94 × 1.1 mm) which is what I am plugging
into Freesurfer.
There is actual data present - changing the windowing settings (brightness
and contrast) at the front it is possible to make out both grey and white
matter. It is at a low intensity compared with the rest of the brain. The
data was acquired some time ago, and I am not sure what the source of drop
off is. Thanks for your advice in advance.
Thanks.
M
On Mon, Jan 23, 2012 at 11:07 PM, Bruce Fischl <fis...@nmr.mgh.harvard.edu>
wrote:
Hi Mahinda,
sorry, I meant to respond to this. It's hard to tell from the
image - is there actually data in the frontal regions? What is
the source of the drop-off? Is it a slab selective acquisition
and is anterior/posterior the slab direction?
cheers
Bruce
On Mon, 23 Jan 2012, Mahinda Yogarajah wrote:
Dear Experts,
Sorry if this is a repost, but I was not sure it got
posted.
I have a few subjects that I want to salvage and use
where there appears to
be significant signal inhomogeniety in the last few
frontal slices (see
T1.mgz in attached figure 1). Despite the use of
control points (placed
with careful adjustments of windowing parameters), I
still can't encompass
all of the the gyri right at the front (see
brainmask.mgz coronal slice in
figure 2). I would really appreciate some advice on
how to proceed from
here. Is placing white matter voxels in wm.mgz a
possible solution ? Or is
there another solution ?
Thanks.
M
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