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<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=043480415-08042009>Here it is.</SPAN></FONT></DIV><BR>
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<FONT face=Tahoma size=2><B>From:</B> mristudio-users-bounces@mristudio.org
[mailto:mristudio-users-bounces@mristudio.org] <B>On Behalf Of
</B>[Seongjin]<BR><B>Sent:</B> Tuesday, April 07, 2009 10:31 PM<BR><B>To:</B>
DTI Studio, ROI Editor, Landmarker Questions/Support<BR><B>Subject:</B>
[Mristudio-users] Re: re： How to do a Tailarach
transformation?<BR></FONT><BR></DIV>
<DIV></DIV>Dear Susumu,<BR><BR>Do you have relevant literature on your
opinion:<BR><BR>"...<FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">In reality, within
practical imaging time, I don’t think you can observe such effect clearly. Our
past measurement (Landman et al, NeuroImage) suggests once you have
12-orientation or more, you don’t see much
differences..."</SPAN></FONT><BR><BR>If you had, could you share the
literature?<BR><BR>Thanks.<BR><BR>- SC<BR><FONT face=Arial color=navy
size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT><FONT
face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><BR></SPAN></FONT><BR>
<DIV class=gmail_quote>2009/4/7 susumu <SPAN dir=ltr><<A
href="mailto:susumu@mri.jhu.edu">susumu@mri.jhu.edu</A>></SPAN><BR>
<BLOCKQUOTE class=gmail_quote
style="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid">
<DIV lang=EN-US vlink="blue" link="blue">
<DIV>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Hi
Jinsong,</SPAN></FONT></P>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">It depends on whom
you ask the question, but here is my opinion.</SPAN></FONT></P>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">When you are using
diffusion “tensor” imaging, all data will be fitted to obtain only the 6
tensor elements. Therefore, you need only 6 directions mathematically.
However, such measurement takes only less than 1 min and do not have enough
SNR (signal-to-noise ratio). To enhance the SNR, you need to acquire more
data.</SPAN></FONT></P>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Usually people spend
4-10 min of time for DTI, in which you can acquire about 30 – 100 images. Then
you have several options. For example, you can repeat the 6-orientation
measurement 5 times (total 30) or one 30-orientation measurement within the
same amount of time (should be within 5 min). </SPAN></FONT></P>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Purely from
mathematical point of views, I don’t think 6-direction x 5 vs 30-orientation
have that much difference in terms of overall SNR. However, it is true that
the 6-orientation measurement has more orientation-dependent inhomogeneity in
SNR. This means, certain orientations can be measured with higher SNR while
some orientation has poorer SNR. By adopting more orientations, such
orientation-dependent SNR profile becomes more homogeneous (less orientation
dependent).</SPAN></FONT></P>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">In reality, within
practical imaging time, I don’t think you can observe such effect clearly. Our
past measurement (Landman et al, NeuroImage) suggests once you have
12-orientation or more, you don’t see much differences.</SPAN></FONT></P>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Some researchers are
seeking for diffusion “more than one tensor” imaging. If you want it, you may
need more than 30 orientations and higher b-values. So, you may need to design
very different protocols.</SPAN></FONT></P>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Susumu</SPAN></FONT></P>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<DIV>
<DIV style="TEXT-ALIGN: center" align=center><FONT face="Times New Roman"
size=3><SPAN style="FONT-SIZE: 12pt">
<HR align=center width="100%" SIZE=2>
</SPAN></FONT></DIV>
<P><B><FONT face=Tahoma size=2><SPAN
style="FONT-WEIGHT: bold; FONT-SIZE: 10pt; FONT-FAMILY: Tahoma">From:</SPAN></FONT></B><FONT
face=Tahoma size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Tahoma"> <A
href="mailto:mristudio-users-bounces@mristudio.org"
target=_blank>mristudio-users-bounces@mristudio.org</A> [mailto:<A
href="mailto:mristudio-users-bounces@mristudio.org"
target=_blank>mristudio-users-bounces@mristudio.org</A>] <B><SPAN
style="FONT-WEIGHT: bold">On Behalf Of </SPAN></B>jinsong tang<BR><B><SPAN
style="FONT-WEIGHT: bold">Sent:</SPAN></B> Tuesday, April 07, 2009 12:52
PM<BR><B><SPAN style="FONT-WEIGHT: bold">To:</SPAN></B> DTI Studio, ROI
Editor, Landmarker Questions/Support<BR><B><SPAN
style="FONT-WEIGHT: bold">Subject:</SPAN></B> [Mristudio-users]
re</SPAN></FONT><FONT face="MS Mincho" size=2><SPAN lang=JA
style="FONT-SIZE: 10pt; FONT-FAMILY: 'MS Mincho'">：</SPAN></FONT><FONT
face=Tahoma size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Tahoma"> How to
do a Tailarach transformation?</SPAN></FONT></P></DIV>
<DIV>
<DIV></DIV>
<DIV class=h5>
<P><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"></SPAN></FONT> </P>
<DIV>
<DIV>
<P><FONT face="Times New Roman" size=3><SPAN style="FONT-SIZE: 12pt">Hello
everyone,</SPAN></FONT></P></DIV>
<DIV>
<P><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"></SPAN></FONT> </P></DIV>
<DIV>
<P><FONT face="Times New Roman" size=3><SPAN style="FONT-SIZE: 12pt">Now the
Siemens 3.0 T MRI scanner can collect </SPAN></FONT>30
non-collinear directions diffusion data. Does this helpful for
fiber tracking ?</P></DIV>
<DIV>
<P><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"></SPAN></FONT> </P></DIV>
<DIV>
<P><FONT face="Times New Roman" size=3><SPAN style="FONT-SIZE: 12pt">But I
found most paper only use 12 directions. Does anybody know
why?</SPAN></FONT></P></DIV>
<DIV>
<P><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"></SPAN></FONT> </P></DIV>
<DIV>
<P><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt">Best,</SPAN></FONT></P></DIV>
<DIV>
<P><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"></SPAN></FONT> </P></DIV>
<DIV>
<P><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt">Jinsong</SPAN></FONT></P></DIV></DIV>
<P><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"></SPAN></FONT> </P>
<DIV style="TEXT-ALIGN: center" align=center><FONT face="Times New Roman"
size=3><SPAN style="FONT-SIZE: 12pt">
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</SPAN></FONT></DIV>
<P><FONT face="Times New Roman" size=3><SPAN style="FONT-SIZE: 12pt"><A
href="http://cn.rd.yahoo.com/mail_cn/tagline/card/*http:/card.mail.cn.yahoo.com/"
target=_blank><FONT face="MS Mincho"><SPAN lang=JA
style="FONT-FAMILY: 'MS Mincho'">好玩</SPAN></FONT><FONT face=SimSun><SPAN
lang=JA style="FONT-FAMILY: SimSun">贺</SPAN></FONT><FONT
face="MS Mincho"><SPAN lang=JA
style="FONT-FAMILY: 'MS Mincho'">卡等你</SPAN></FONT><FONT face=SimSun><SPAN
lang=JA style="FONT-FAMILY: SimSun">发</SPAN></FONT><FONT
face="MS Mincho"><SPAN lang=JA
style="FONT-FAMILY: 'MS Mincho'">，</SPAN></FONT><FONT face=SimSun><SPAN
lang=JA style="FONT-FAMILY: SimSun">邮</SPAN></FONT><FONT
face="MS Mincho"><SPAN lang=JA
style="FONT-FAMILY: 'MS Mincho'">箱</SPAN></FONT><FONT face=SimSun><SPAN
lang=JA style="FONT-FAMILY: SimSun">贺</SPAN></FONT><FONT
face="MS Mincho"><SPAN lang=JA
style="FONT-FAMILY: 'MS Mincho'">卡全新上</SPAN></FONT><FONT face=SimSun><SPAN
lang=JA style="FONT-FAMILY: SimSun">线</SPAN></FONT><FONT
face="MS Mincho"><SPAN lang=JA
style="FONT-FAMILY: 'MS Mincho'">！</SPAN></FONT></A></SPAN></FONT></P></DIV></DIV></DIV></DIV><BR>_______________________________________________<BR>Mristudio-users
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