Lumina GE HDX trigger issue

Hardware General
1

Dear all,
We recently got a lsc-400b Lumina equipment, which is connected to a HDX GE MRI machine, and to a laptop with presentation software (v13). We try for different mri sequences but we could only read a couple of pulses. Lsc-400 was connected to the r15 port of the resonator using a trigger lumina cable for GE. could anyone give us some advice on this? (we check for the dip switch and both were top).

Any feedback is appreciated

cheers,

Francisco

2

Hi Francisco, what Mode was the Lumina controller set to (e.g. ASCII)?

3

Lumina GE HDX trigger issue

Dear Hisham,

Thanks for your reply, we set the LSC400B in ASCII/MEDx mode (dip switchs up). Lumina seems not receive any pulse, we previously tested it (LSC-400B) in a Siemens Intera MRI (dip switch down) and it worked perfectly, do you have any suggestions?

Cheers,

Francisco

4

When you refer to the DIP switches, are you referring to the optical isolation ones on the bottom of the controller? or the ones inside (shown in the picture on this page)?

5

ge lsc-400 trigger

Dear Hisham,

Sorry I think that my post was confusing, I meant the switches found on the inside of the LSC-400B which allow dectect longer pulses (for GE) and shorter (Philips, Siemens).
I wanted to mention that we consider the position of the switchs so you could rule this out in your analysis of the problem.

Correction: I mentioned in a previous post we had tested the LSC-400B on a “Siemens Intera” what was clearly a mistake on my part, the MRI where the LSC-400B was initially tried and it worked perfect was a Philips Intera 1.5 T.

Thanks in advance,

Francisco

6

Lumina GE HDX trigger issue

Dear Hisham,

Do you have any idea about what might be happening?, please…

thanks

Francisco

7

Francisco, from the little that I know about Presentation, they prefer to collect input over the parallel port, not serial. Have you tried this approach?

Meanwhile, we have worked with the folks at Neurobehavioral Systems and released a Cedrus XID plug-in for Presentation. See the news release. Beware though that the plug-in will not work if you interface with Siemens scanners because of the very short pulse duration.

8

Lumina GE HDX trigger issue

Thanks Hisham for your answer,

I will try again using the extension for presentation.

According your last post:

“they prefer to collect input over the parallel port, not serial. Have you tried this approach?”

What do you mean?, because the LSC-400B ouput is a serial not a parallel port. Exist another way to connect Lumina to a computer with presentation?

Thanks in advance,

Francisco

9

The LSC-400B controller provides both serial and parallel outputs. The parallel output comes out on our Accessory Connector. See this page for details.

10

ge lsc-400 trigger

Dear Hisham,

I was testing the system (Presentation+Lumina ), using a TTL pulse generartor to emulate the MRI pulses and I noted that everything work perfect, every pulse was readed by the test port application on presentation software. Then my suspect now is over the MRI machine output, do you know where I can get some information about the output ports and the characteristics of pulses? or if anyone can share that information with me?
Maybe the sequence parameters are relevant in order to generate the pulses.

Our MRI is a GE HDX 1.5 T version software 15.0_0947A for linux.

Any, any information will be appreciated,

Francisco

11

I really don’t know where to get this information. It sounds like a question for your local GE engineer. However, when we were designing the Lumina LSC-400 controller back around 2000-2001, an engineer at GE told us that the pulse being sent is a differential voltage (not TTL), around 500-700 milliseconds duration.

12

Lumina GE HDX trigger issue

Thanks Hisham, I will contact the local GE engineer. I will post the findings anyway.

13

Dear Francisco,

Can you please share your experience with GE and Lumina controller, getting trigger pulse, etc. We are trying to connect a refurbished old GE to lumina system for fMRI. Thank you for your help.

Cemil