The 10.000 brains from Brussels project takes place at the radiology department of UZ Brussel, and is a collaboration with the AIMS lab of VUB. With this project, we aim to gather brain Magnetic Resonance Images (MRI), more specifically anatomical T1 images, that were protocolled as being "normal".
Why so many healthy brains?
In literature about neurological disorders, such as Multiple Sclerosis (MS) and dementia, there has been a lot of interest lately in the concept of "Brain Age".
Brain age is the chronological age that we predict a certain brain to be. However, in order to be able to decode how old a brain is, we need to create a healthy reference curve; an association between the morphology of a healthy brain (MR image) and the chronological age corresponding to it. Once we have made the association, we can predict how old a brain is by comparing it to the healthy reference curve.
If the brain is healthy, this is going to be very close to the chronological age of that person, i.e. how old the person is at the moment. However, a brain that is affected by a neurological disorder such as MS or dementia will look older than the person actually is at that moment. Hence, the brain age is higher than the chronological age.
Brain age relative to the chronological age could thus give us insight in how old the brain should be, and thus detect any over- or underestimation of brain age; this is a quantity called Brain-Predicted Age Difference (BPAD = brain age - chronological age).
Why are Brain Age and BPAD interesting?
Both brain age and BPAD, but in particular BPAD, can be regarded as interpretable, summarizing quantities of the brain MRI. They represent the "extent of damage" of that brain. We hereby note that we can only say something about the damage in terms of volumetry, i.e. how much brain tissue is present.
As briefly mentioned above, the following scenarios are possible:
- BPAD positive: the brain age is overestimated compared to the chronological age. There is likely to be increased loss of brain tissue.
- BPAD = 0: the brain age is comparable to the chronological age. The amount of brain tissue appears to be normal.
- BPAD negative: the brain age is underestimated compared to the chronological age. This process is less well understood, but for example aerobic exercise might increase brain volume1, resulting in a lower brain age prediction.
Besides the fact that brain age and BPAD are intuitive markers of brain health and could therefore be beneficial in clinical routine, they are also thoroughly investigated in research on neurological disorders. Associations with clinical variables such as physical and cognitive disability have already been established.2
Who will benefit from this project?
Last but not least, the concept of brain age can be applied to any disorders affecting the brain. The set of healthy brain MRIs that we will gather with this project could therefore be beneficial to many departments within both the UZ Brussel and the VUB.
1. Colcombe SJ et al. 2006, Aerobic Exercise Training Increases Brain Volume in Aging Humans, The Journals of Gerontology: Series A, Volume 61, Issue 11, November 2006, Pages 1166–1170, https://doi.org/10.1093/gerona/61.11.1166
2. Kaufmann T et al. 2019, Common brain disorders are associated with heritable patterns of apparent aging of the brain. Nature neuroscience, 22(10), 1617-1623. https://doi.org/10.1038/s41593-019-0471-7