Time point_regarding

Submitted by Ramesh on Wed, 08/21/2013 - 12:05

 Dear Members,

Please accept my love and greetings. Just entered in this forum.

Recently I have downloaded REST as well as DPRASF soft ware and using for fMRI analysis. I am learning functinal connectivity analysis by using these software. I have dwnloaded a data set from ADHD 200 datasets. There are totally 48 fMRI and sMRI datasets. Since first time I am doing this analysis I have taken only one fMRI (single subject) and converted it into Nifty pairs (img/hdr) by using REST utility.

I entered all there parametrs in the DPARSF (Basic) except time ponit. I would like to know how to define timepoint for this single data. Herewith I have attached the scan parameters also. NAy help will be appreciated.

Thanks in advance,
Ramesh


AttachmentSize
PDF icon ADHD-200 fMRI parameter.pdf34.91 KB

Comments

Submitted by ZHANG_RESTadmin on Wed, 08/21/2013 - 17:59

 Hi, the time points of the fMRI data, is How many images you collected for an individual data in a fMRI scan.
Suppose you have a 6min fMRI scan, the TR is 2s, that means in every 2s, you collect 1 image of the whole brain.
So, totally, 6min = 6*60s=6*60/2 = 180 time points.


Submitted by Ramesh on Wed, 08/21/2013 - 19:15

 Thank you very much for your reply. Since it is downloaded dataset, I don't know the total time duration. I have attched the scan parameter. I would know how to calculate the total time duarion from the given different parameters. Please let me know.

Thanks in advance
Ramesh

 

Submitted by Ramesh on Thu, 08/22/2013 - 18:12

 Hi
Still I am findimg difficault. DPARSF is not considering the time point 266. I am just stuck up basic level itself. Please provide me some solution.

Thanks
Ramesh

Submitted by Ramesh on Thu, 08/29/2013 - 18:37

Thank you ery much for ypur reply.

I would like to know how to calculate sample size for a study on meditation. This meditation has 4 stages. I would like to run ti as 4 sessions. For each session the time duaration may vary. But total time duration will about 20 minutes. 

I dont have any pilot data.

Please tell me how to calculate sample size

Thanks
Ramesh

Submitted by ZHANG_RESTadmin on Sat, 08/31/2013 - 18:14

 if you want to run it like 4 sessions, you can calculate the sample size (if you meaned sample size = how many TRs in each session) by calculating how many dicom files in each session. Basically there are two possibilities: num of dicom files = sample size * number of slices in each volume,  the other is num of dicom files = sample size.   But you have to know which images belong to which session first.