Dear All
I've recently started using Dartel to create a standardised template brain from a paediatric cohort of about 70 children of quite varied ages. I'm interested in comparing electrode placement across this group who've undergone a functional neurosurgical procedure. The images I'm using have been obtained from a 1.5T scanner, with patients in a leksell frame and so are not particularly high resolution. Dartel has created a good looking template, and for most of the patients the "create warped" warps the individual brains from native space to the template very nicely. For about 5 of the scans though the warped images are very poorly aligned to the template, looking very distorted in 1 or 2 cases. The native brains this has affected have a degree of plagiocephaly or brachycephaly, but the dartel process has handled other brains in the cohort with these appearances well. Given the resolution of the original scans I'd resigned myself to achieving a less then perfect registration to a standard template, but I'm surprised to see it fail quite so markedly with this limited number of scans. I'd be very grateful for any suggestions as to what might be the cause for this, or any suggestions for how best to subsequently register these brains to the template. I have essentially used the default settings for dartel throughout the process.
Many thanks
Dan Lumsden
Clinical Research Fellow
Complex Motor Disorder Service
Evelina Children's Hospital
London
|