help > ArtRepair Error / Art Detection vs ArtRepair
May 18, 2020  07:05 PM | Kelly Hiersche - The Ohio State University
ArtRepair Error / Art Detection vs ArtRepair

I am new to using SPM (and functional processing generally). I have data from a task fMRI experiment. Briefly, the outliers that were identified in my data using Art Detection and Art Repair were VERY different (Art detection: 15% data removed, ArtRepair 100% data removed), despite similar settings. Does anyone know why this might be? 

Longer explanation: 
I began by using Art Detection to find out how many outliers were in my functional data. As a next step (as I am new to processing), I decided to try using ArtRepair, instead, to repair these volumes, instead of just including them as a 1st level covariate. Using the setting Motion Threshold (mm/TR) = 1mm, ALL of my volumes (495 total) were thrown out. When I processed the same data using Art Detection with the settings Z-score = 5 S.D. and movement = 0.9mm, less than 5% of the data was identified as an outlier. Does anyone know why the volumes identified by the two programs would be so vastly different? 

I got an error: 

art_addmargin (line135)
elseif xout(xendL(length(xendL))-imarg) >0

I checked the art_addmargin code. This section is used when the final volume is being thrown out, which is the case for this data and current settings. Does anyone know if this error is due to the matlab version I am using (SPM12 Matlab2015b), or if it is because so many volumes are removed, or something else? 

Thank you,

Attachment: ArtRepair_graph.JPG

Threaded View

ArtRepair Error / Art Detection vs ArtRepair
Kelly Hiersche May 18, 2020
Kelly Hiersche Jul 13, 2020