Talk:Neuroimaging Data Processing/Processing/Steps/Slice Timing

Slice timing order inference removed
Hello, I tried the "slice timing order inference" suggested in a previous version of the article, and it did not work. Here was the suggested method:

«However, sometimes it's hard to get connected to the persons, and SPM provides a "Display" option that might allow to infer the slice order on old sequences. If you want to check the slice ordering in one image, you could load the image under "Display" option in SPM. On the left-side there is a panel showing the coordinates of the cursor both in voxel coordinates and millimetres. Change the crosshairs to a voxel with coordinate of z=1, and this would be the first slice of current volume. Then, fix the x and y values in the crosshairs, and try to increase the z value gradually from 2 to the number of slices, concomitantly the millinetres in z axis will change. From the increase on the step, we could know the direction either ascending or descending, and the interval equals to one voxel or two voxels. In this way, we could infer the slice order correspondingly.»

I tested this approach on two bold series: one acquired in sequential ascending order, the other one in sequential descending order. Both gave exactly the same result, there was no difference in how the mm or vx behaved when moving the cursor up the Z axis, it was always incrementing by about the same percentage, which represents the slice gap + slice thickness, so this is good for slice spacing inference, but not for slice order.

I removed this paragraph and renamed the section to remove this seemingly bogus info (or was it maybe working on old machines? Anyway nowadays it does not work, on machines that are already 10 years old...).

If I misinterpreted this method, please reinstate it with some clarification on how to appropriately use it. --Signimu (discuss • contribs) 23:18, 30 May 2019 (UTC)