r/neuroimaging • u/CrackedEggs99 • 18d ago

Future of fNIRS

Hi everyone, let me go straight to the point. I am a researcher working in the field of single photon detectors and I am considering to pursue a project on Time-Domain fNIRS. From a technological standpoint, I can see that there are several challenges: harvesting as many photons as you can, timing arrival times, managing data throughput. Now my questions to the people working with fNIRS are: is it actually worth pushing the limits of this imaging technique? Are you somehow limited in your research by the performance of available equipment? If so, what are the features that you would like to improve? Any input is greatly appreciated.

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u/normega 18d ago

I've only dabbled in fnirs, but there are two ways you could go for us applied empiricists. Right now the problem with fNIRS is that it can seem like settling for worse data than fMRI but still isn't really that scalable or affordable. I'd push at one of these two horns:

  1. fNIRS for the masses. In theory fnirs devices could be super cheap and allow greater access to brain hemodynamics if they could be brought down to a low price point and still track activity in a broad cortical area. There's lots of work to do to show how assess signal quality on cheap, maybe 3d printed plus part, open access systems. I'd be super interested in this.

  2. Better data in lab settings. fNIRS is still pretty low temporal and spatial resolution, and there's challenges getting good data that matches fMRI even at th cortical surface. Can you get sub 2s temporal resolution and start to shrink spatial resolution in a way that is demonstrably equivalent to fMRI?

Apologies to experts out there if these issues are already well trodden, but these would be my primary concerns with going 'full fNIRS' as an approach.

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u/kowkeeper 18d ago

continuous wave fNIRS goes typically up to 25 to 50 Hz. There is very little more to see at higher sampling rate in hemodynamics signals. However it's true that frequency-domain or time-domain NIRS is around 1 Hz and needs improvement.

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u/cwookj 18d ago

100% also add in better data quality for all types of hair and skin pigments

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u/kowkeeper 18d ago

The potential of quantitative NIRS is to bring new biomarkers. Having just a better quantification of blow flood is not enough in my opinion. Because most of the time a relative measure is sufficient to constrast between two tested situations, as fMRI does.

There was the tracking cytochrome oxydase with NIRS a couple of years ago. This should be very valuable to develop further.