Sergio,
We do spatial normalization of SPECT scans from both head-injured and stroke
patients. Indeed, using just the 12 parameter linear affine does a better
job in NOT removing lesions. However, we often don't get good normalization
with just 12 PLA. To circumvent this, and to prevent the non-linear basis
functions from healing the patient's scans, we use the smallest standard
basis fxn (2x2x2), with 8 iterations. This seems to work nicely.
The type of normalization can be changed by clicking the "Defaults" button,
then going to normalization, then selecting the parameters you wish to use.
Understand that these are changed back to the default defaults whenever you
restart SPM from scratch.
Hope this helps,
James
===================
= James C. Patterson II, MD/PhD
= Department of Psychiatry and Behavioral Sciences
= Clinical Research Center
= University of Texas Medical Branch
= Galveston, Texas
= Email: [log in to unmask]
= http://marlin.utmb.edu/~japatter/patterso.htm
=======================
-----Original Message-----
From: Sergio Carvalho [mailto:[log in to unmask]]
Sent: Friday, January 29, 1999 5:41 AM
To: SPM Mailing List
Subject: Spatial normalization and stroke patients
<< File: Card for Sergio Carvalho >> Hi,
Does anyone have experience on the results of spatial
normalization on
stroke patients? I have a scan of a stroke patient, where a
reduced
perfusion area is easily perceivable. However, after spatial
normalization the dark area completely vanishes. Why?
--
Sergio Carvalho
---------------
[log in to unmask]
If at first you don't succeed, skydiving is not for you
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|