Hi Sam, The HCP diffusion data was collected with the b-values interleaved throughout each run. You might want to search the HCP-Users archive for more information/answers to questions on this. Specifically, here’s a relevant thread with a link to the reference with details on the data: http://www.mail-archive.com/hcp-users%40humanconnectome.org/msg00108.html
Best, Jenn Jennifer Elam, Ph.D. Outreach Coordinator, Human Connectome Project Washington University School of Medicine Department of Anatomy and Neurobiology, Box 8108 660 South Euclid Avenue St. Louis, MO 63110 314-362-9387 [email protected] www.humanconnectome.org From: [email protected] [mailto:[email protected]] On Behalf Of Connectome Issues Sent: Monday, October 13, 2014 11:45 AM To: Cunningham, Samantha (NIH/NIAAA) [F] Cc: [email protected]; [email protected] Subject: Re: [HCP-Users] B-values for DWI data Hello Samantha, I'm forwarding your two recent inquiries to the HCP Users email group, which contains a very active community of consortium users and other researchers who are actively using the data. If you are not a member, I highly recommend signing up for the email list here: http://humanconnectome.org/contact/#subscribe Regards, Will On Tue, Oct 7, 2014 at 2:20 PM, Cunningham, Samantha (NIH/NIAAA) [F] <[email protected]> wrote: Hello, I recently downloaded unprocessed diffusion data from the Human Connectome database (WU-Minn HCP Data à 500 subjects à 10 unrelated subjects). However, I am having a hard time understanding what the b-values are for each of the 6 datasets included for each subject. The Reference Manual specifies that the 6 dMRI scans include 3 b-values x two phase encoding directions, but for “100307_3T_DWI_dir97_LR.bval” for example, the file seems to contain more than 3 b-values (I have attached a screenshot). I am used to having gradient files with all the same b-values (except for the b0 value)—I am not familiar with the method of using many different b-values in one run. Can you please shed light on this or provide a reference article that may be helpful? Thank you for your time and help! Samantha Cunningham, Ph.D. Postdoctoral Fellow National Institutes of Health|NIAAA|LNI [email protected] _______________________________________________ HCP-Users mailing list [email protected] http://lists.humanconnectome.org/mailman/listinfo/hcp-users _______________________________________________ HCP-Users mailing list [email protected] http://lists.humanconnectome.org/mailman/listinfo/hcp-users
