Diffusion imaging is not limited to basic measures such as classical DTI FA (fractional anisotropy); other microstructure measures can be of major interest. Free-water is a telling example.
Imeka’s diffusion imaging tools are able to measure extracellular water fraction (free-water), which in turn can be sensitive neuroinflammation.
There is currently no way to measure inflammation in white matter. Certain PET markers are in development, but they are not considered as usable options in the near future. Furthermore, PET imaging is a highly invasive and expensive.
Imeka’s infrastructure is already used in a clinical trial setting. For example, our team has worked on existing databases (ADNI, ADNI+, ADNI2) and significant differences between normal, MCI and AD groups were observed based on this measure.
The diffusion MRI signal can be modeled by a tissue part and free-water part. It’s a simple, yet powerful way of assessing extra-cellular water, which can be associated with neuroinflammation.
It’s a simple, yet powerful way of assessing extra-cellular water which can be associated with inflammation.
The acquisition time necessary for us to get proper data to perform processing is short. In the order of 5 minutes of diffusion MRI in the protocol.
Legacy dataWe are also able to work with data that was acquired in the past. With a limited amount of directions of acquisition (20 or more), we can perform free-water modelling and advanced tractography from legacy data.
Free-water imaging can also be used to remove free-water from the signal. This is particularly useful in cases of brain lesions in order to discern what’s hidden within.
The best example? Multiple Sclerosis. We have been able to “track” through lesions by removing the free-water component of the signal.
Differentiating edema from tumour
Another very important aspect of the free-water component for neurosurgeons is that we can help differentiate edema from tumor and from sane tissue in the brain.