firmm > Volume arrival delay
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Sep 27, 2018  11:09 AM | Ian Ballard - University of California, Berkeley
Volume arrival delay
Hello FIRMM community,

I had an issue on our Siemens Trio. We were able to successfully install FIRMM. However, our images arrive at a delay of 4-8 seconds, usually in packets of 2 or 3 volumes. Although this is not an issue with the FIRMM software, I was hoping someone in the community had encountered a similar problem.

The reconstruction is running real time, and the Inline Display displays images in real time, but the subsequent writing to the database happens only periodically, with a delay of what usually amounts to a TR or two for EPI. We have a Trios running VB17 software.

Any help would be greatly appreciated,

Ian
Sep 28, 2018  09:09 AM | Eric Earl - Oregon Health & Science University
RE: Volume arrival delay
Ian, what is your TR?  Is it about 2 seconds (just guessing based on your delay and volume counts there)?
Sep 28, 2018  10:09 AM | Ian Ballard - University of California, Berkeley
RE: Volume arrival delay
Originally posted by Eric Earl:
Ian, what is your TR?  Is it about 2 seconds (just guessing based on your delay and volume counts there)?
Hello Eric,

Yes the TR is 2 seconds. Thanks!
Sep 28, 2018  11:09 AM | Eric Earl - Oregon Health & Science University
RE: Volume arrival delay
Ian,

At that TR I can't imaging why your reconstruction computer would take that long to get DICOMs over your network to the FIRMM computer.  I guess you could investigate your network speed bgetween the scanner and the firmm PC and maybe evaluate your scanner's reconstruction speed separately?

~Eric
Sep 28, 2018  01:09 PM | Ian Ballard - University of California, Berkeley
RE: Volume arrival delay
Hi Earl,

A suggestion from the real-time fMRI list fixed the problem. I thought I would let you know in case it interests you.

It turns out that the default is for the computer to write data every 5 seconds on older systems, which is why scans appeared in alternating packets of 2 or 3 (at a 2s TR). You can change this to write every 500ms by setting "SendBuffered" to False using ideacmdtool and xbuilder and scans arrive in regular intervals of one TR +- a handful of ms.

Thank you,

Ian
Oct 1, 2018  07:10 AM | Eric Earl - Oregon Health & Science University
RE: Volume arrival delay
Originally posted by Ian Ballard:
Hi Earl,

A suggestion from the real-time fMRI list fixed the problem. I thought I would let you know in case it interests you.

It turns out that the default is for the computer to write data every 5 seconds on older systems, which is why scans appeared in alternating packets of 2 or 3 (at a 2s TR). You can change this to write every 500ms by setting "SendBuffered" to False using ideacmdtool and xbuilder and scans arrive in regular intervals of one TR +- a handful of ms.

Thank you,

Ian

Nice discovery!  Thanks for the info cross-posting to our forum.

~Eric