 |
 |
Dear fsl users, I used siena and sienax to process longitudinal and cross sectional 25 data sets. Each data set consists of 2 T1 scans at 2 different intervals. Both scans are of different FOV and quality. The first time interval's scan is of 256x256x124voxels and 1.093x10.93x1.5mm voxel dimensions while the other is of 256x256x50 and 1.093x1.093x 2.5mm. I had to process 10 data sets of Controls (with scans at 2different intervals ) and 15data sets of Parkinson Disease patients (with scans at 2 different intervals also) and, correct me if i'm wrong, i used the same parameters settings for all the data sets in siena and sienax respectively, in order to have an objective comparison of the results. In almost all of the data i had very good results except from 3 data sets. In these data sets the Bet tool failed totally, hence both siena and sienax gave bad results and siena printed in 2 out of 3 datasets a warning: “Probably failed consistency, check for standard space registrations” I have the following questions: 1)what's the meaning of the siena's warning output? Cause i didn't find any info about that in fsl's web page /lectures. 2)why i didn't have these problems in siena with the other data sets , since all of them are of different quality and FOV ? 3)If i change sienax parameters then i'll probably find a set that will help Bet to succeed but if i'll do that then how can i compare the results of all my data sets since the comparison won't be objective?? 4)Is it wrong that i used siena to make longitudinal analysis in data that have different FOV, without reducing the FOV of the “bigger” image till it reaches the “smaller” one? 5)I used siena in all my data with the following set up: siena A B “parameters settings” where A is the scan with the smaller FOV and less resolution (2.5mm ) and B the scan with the bigger FOV and higher resolution (1.5mm). If i change the sequence of the scans in siena :siena B A “parameters settings” there is a difference in the PBVC. why is that? 6)In some results i noticed that after segmentations the eyes were not excluded. does this induce a serious error in siena/sienax results? and if yes how can i avoid that without changing the siena/sienax parameters which will make the final results not objective for comparison with the other results of my data?? Thank you once again for your valuable support Antonios-Constantine Thanellas P.S. I've uploaded one of the data sets where i had these problems with the output of the siena script on these data. They are control data from the same subject in different intervals. The ref ID is :377949