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Hello, I should probably answer this one: > I have a dataset of paediatric MRI and PET scans (1-18y) and I am keen to create a paediatric template to be used as a reference of normalisation of the scans. OK, good idea :) > I am writing to confirm that the following steps are correct: Do I need to segment the MRI scans and use the GM maps in the Estimate regression parameters module of SPM8? Having obtained the .TOM file I just need to run the second module (Create template). Is this correct? Yes: if you do not want to use the regression data provided (which indeed does not cover infants), you will first need to segment your dataset, then run the "estimate regression parameters", and then the "Create templates" step on the results from that analysis. However, note that in order to obtain good quality parameters, you need a large cohort, and two, note that you need to obtain all 6 (unmodulated) tissue classes so that you can construct a 6-class tissue prior in the end (to be used as the spatial normalization target). Another alternative would be to use the brand-new Template-O-Matic successor, the CerebroMatic toolbox, which is now published (http://journal.frontiersin.org/article/10.3389/fncom.2017.00005/full) but embarrassingly not online yet (but should be soon at https://irc.cchmc.org/software/cerebromatic.php). This allows for a more fine-grained tissue class generation from 13 months to 75 years, using a much cooler approach than a simple GLM (and it even comes with a manual ;) We should be able to upload soon but if you can't wait I can send you a pre-final version by private mail. > Additionally, I am wondering whether it would be better to split the scans in different age ranges (I am assuming I will create an average paediatric template across 1-18 years old following the above stated methodology). My main concern is that I would like to create PET templates based on the MRI one, hence the metabolism is very different across ages. Whichever parameter you look at will be very different across this age range, which again will be an issue for each analysis I can currently think of. Cheers Marko -- ____________________________________________________ Prof. Dr. med. Marko Wilke Facharzt für Kinder- und Jugendmedizin Leiter, Experimentelle Pädiatrische Neurobildgebung Universitäts-Kinderklinik Abt. III (Neuropädiatrie) Marko Wilke, MD, PhD Pediatrician Head, Experimental Pediatric Neuroimaging University Children's Hospital Dept. III (Pediatric Neurology) Hoppe-Seyler-Str. 1 D - 72076 Tübingen, Germany Tel. +49 7071 29-83416 Fax +49 7071 29-5473 [log in to unmask] http://www.medizin.uni-tuebingen.de/kinder/epn/ ____________________________________________________