In my honest opinion, all subjects need to be processed the same way. If you have 2 scans, you could use the suggested approaches, or you could coregister them, then average them in. After averaging , you can do the rest of the processing. Averaging should give similar as increasing the NEX. On Thursday, May 19, 2011, Jonathan Peelle <[log in to unmask]> wrote: > Dear Steven, > >> We are comparing two groups of 13 subjects with DARTEL VBM8. I know this >> is underpowered, but wondered if there is any way to use the multiple T1 >> images that were acquired for some of the subjects (in the same session). My >> initial thought is to process all T1s and use the quality check to see if >> there is a "better" image when I have two for a given subject. Are there >> better ways to use multiple T1s? > > In the "new segment" option in SPM8, you can specify multiple > modalities of images for segmentation. I assume you could also > provide SPM with 2 T1 images. SPM will then use the combined > information across images to assign tissue class probabilities, and in > general I would think that more data would provide a more accurate > result. However, I think you'd want to process all of your subjects > the same way. So if you only have multiple T1s for a subset, I would > probably stick with the approach you suggest—see if you can identify a > "better" image. (Or, if this is hard to determine, then just use the > first.) But if anyone else has alternate approaches, I'd be very > interested to hear! > > Best regards, > Jonathan > -- Best Regards, Donald McLaren ================= D.G. McLaren, Ph.D. Postdoctoral Research Fellow, GRECC, Bedford VA Research Fellow, Department of Neurology, Massachusetts General Hospital and Harvard Medical School Office: (773) 406-2464 ===================== This e-mail contains CONFIDENTIAL INFORMATION which may contain PROTECTED HEALTHCARE INFORMATION and may also be LEGALLY PRIVILEGED and which is intended only for the use of the individual or entity named above. If the reader of the e-mail is not the intended recipient or the employee or agent responsible for delivering it to the intended recipient, you are hereby notified that you are in possession of confidential and privileged information. Any unauthorized use, disclosure, copying or the taking of any action in reliance on the contents of this information is strictly prohibited and may be unlawful. If you have received this e-mail unintentionally, please immediately notify the sender via telephone at (773) 406-2464 or email.