Hi John, On 09/19/2006 05:24 AM, [EMAIL PROTECTED] wrote:
Of course, I meant 'Radiological' rather than 'Neurological'! Apologies for any confusion.
... and previously wrote:
On 09/19/2006 05:19 AM, [EMAIL PROTECTED] wrote:
I was able to reproduce this behavior, so it seems like something John should look at. Even after changing the Resample x spacing from 0.0 to 1.0, I still get an OUT OF MEMORY stickup and must exit Caret.When opening new .hdr data files exported from Brain Voyager QX, the volumes require reorienting from neurological > LPI. I am using the 'Orientation' tab in the 'Volume attributes' editor to do this. However, although I am able to flip around the X and Y axes without problems, both the 'Rotate Clockwise' and 'Convert to LPI' commands appear to introduce an error such that the 'Resample' tab displays voxel dimensions of 0.000. If I then attempt to resample to 1 x 1 x 1, Caret crashes. Am I approaching the reorientation incorrectly or haveothers experienced the same problem?Any help appreciated John Taylor
Also, when I was playing around trying to solve John's problem, it seemed that changing the Orientation tab's X selection to right-to-left and pressing Convert to LPI didn't x-flip the volume as expected. In the past, this button has worked as far as actually flipping the volume, but the slice display didn't update. So I would then save my x-flipped volume file and reopen it in Caret, replacing any existing structural volumes that were currently loaded. This used to work. In my case just now, it didn't, and I tried using two different input volumes.
But there are a few ways to solve your problem. If Brainvoyager can export NIfTI, then the header should provide Caret the orientation information it needs to do the appropriate flipping upon opening the volume. If Brainvoyager can't export NIfTI, then complain -- loudly.
Other options include using AFNI utilities to convert Analyze to AFNI, then follow up using 3drefit to specify the existing orientation information. Then you can use 3daxialize to actually do the flipping, although I'm guessing it shouldn't be necessary (i.e., I think Caret will flip it to LPI upon opening).
Finally, try playing around with caret_command's -volume-set-orientation feature. Using FSL's very handy avg152T1_LR-marked.hdr, I found that this command caused Caret to display the right on the left:
caret_command -volume-set-orientation LPI avg152T1_LR-marked.hdr avg152T1_LR-marked_LPI+orig.HEAD
The attached right_on_right.jpg is what this volume looks like before running caret_command. Since FSL uses a left-handed coordinate system (right-on-left), they use a negative pixdim[1] to specify the x-flip:
pixdim[1]: <-2.0000>Caret knows to x-flip the volume when it sees negative pixdim[1] in the Analyze .hdr. But if you use caret_command to tell Caret "no, the orientation is actually LPI" (as the above command is doing), then Caret won't x-flip the volume, so you get the result in the right_on_left.jpg capture. Sorry if this is confusing, but it does serve to make the point that it's important to make sure your orientation is correct, using some unambiguous anatomical landmark (or the old vitamin E capsule trick). Occipital petalia and posterior insula are common asymmetries that you can use to check orientation, if you don't have a more obvious landmark.
-- Donna L. Dierker (Formerly Donna Hanlon; no change in marital status -- see http://home.att.net/~donna.hanlon for details.)
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