Typically, the overlapping slice excitation (or even no-gap) leads to leakage of excitation to the adjacent slices and causes signal loss. So you pay a penalty of SNR. <br><br>Usually, within one TR, which is typically around 6-8 seconds, even number slices are excited consecutively and then odd number slices. So, it take about 3-4 seconds before an adjacent slice is excited. <br>
<br>Suppose you hit slice #1. If you have an overlap, you excite a part of slice #2. About 3-4 seconds later, you excite slice #2 but the spins of slice #2 has not been fully recovered and thus you loose signal.<br><br>In your case, because it is just 1.5% overlap, you may not see much impact. Note that the slice excitation profile is not a step function, but has much broader shoulder. So, this SNR penalty by excitation leakage is always there even with gap = 0. <br>
<br>When you reconstruct 3D volume, you have to make the slice thickness 0.03mm thinner (1.97mm). <br><br>If you make sure that the scans are under steady-state (enough prescans), I think you don't have to worry about the effect on DTI calculation, except for SNR.<br>
<br><div class="gmail_quote">On Thu, May 20, 2010 at 11:21 AM, [Seongjin] <span dir="ltr"><<a href="mailto:choisj70@gmail.com">choisj70@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
This might be a stupid question.<div>However, I would like ask your opinions in the community.</div><div>Is there anyone tried DTI acquisition with a bit of overlapping adjacent slices (i.e. negative gap between slices: e.g. 2 mm slice thickness with -0.03 gap).</div>
<div>What would be consequence of this acquisition and adverse influence on the DTI metrics?</div><div><br></div><div>-SC</div>
<br>_______________________________________________<br>
Mristudio-users mailing list<br>
<a href="mailto:Mristudio-users@mristudio.org">Mristudio-users@mristudio.org</a><br>
<a href="http://lists.mristudio.org/mailman/listinfo/" target="_blank">http://lists.mristudio.org/mailman/listinfo/</a><br>
Unsubscribe, send a blank email to: <a href="mailto:Mristudio-users-unsubscribe@mristudio.org">Mristudio-users-unsubscribe@mristudio.org</a><br>
<br></blockquote></div><br>