Hi Kate,
For your future scans, the cheapest way to tell R & L apart is to put a marker nearby one side of the subject's head (I use a small cashew for example -- I think I recal other people using B-vitamine capsules). It shows up nicely on the scan and allows you to
identify with 100% certainty which side is which. Also, if you do so in your next scan and then put the data through the same pipeline as your previous dataset it should answer your question..
cheers
martin
----- Original Message -----
From: Kate MacIver <[log in to unmask]>
Date: Monday, February 26, 2007 12:28 pm
Subject: [FSL] orientation od data
To: [log in to unmask]
> I have a data set of a right-handed task, using a standard protocol
> whichgives activation maps which are bilateral, but predominantly
> ipsilateral M1
> and S1. I have used MRIconvert to convert the data to analyse
> format, but
> checked with avworient that the data is still radiological. I have
> used FSL
> 3.2 for the full data set, but checked samples on FSL 3.3, still with
> strongly ipsilateral activation. I've checked the protocol with a
> healthyvolunteer - on FSL we still have predominantly ipsilateral
> activation, which
> is contralateral when we use a different software package.
> Is there some point within FSL that the data could have been
> flipped? If so,
> is it possible to identify and rectify the problem?
> Kate MacIver
>
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