Rheology is the study of the flow of matter
An interesting brain fact if you are interested
Magnetic Resonance Elastography (MRE) is a developing technology for quantitatively assessing the mechanical properties of tissue. The technology may be considered to be an imaging-based counterpart to palpation, commonly used by physicians to diagnose and characterize diseases.
Apparently brain stiffness decreases one percent per year during normal aging, so our brains are turning to mush as we get older and MS does not help this. Interestingly they find that when you die, just like your muscle stiffen you get rigor mortis of the brain too and your brain stiffens.
So we should all use MRI to look at brains and be cautious with histology, is a conclusion.
Weickenmeier J, Kurt M, Ozkaya E, de Rooij R, Ovaert TC, Ehman RL, Butts Pauly K, Kuhl E. Brain stiffens post mortem. J Mech Behav Biomed Mater. 2018;84:88-98.
Alterations in brain are increasingly recognized as a diagnostic marker for various neurological conditions. Magnetic resonance elastography now allows us to assess brain rheology repeatably, reproducibly, and non-invasively in vivo. Recent elastography studies suggest that brain stiffness decreases one percent per year during normal aging, and is significantly reduced in Alzheimer's disease and multiple sclerosis. While existing studies successfully compare brain stiffnesses across different populations, they fail to provide insight into changes within the same brain. Here we characterize rheological alterations in one and the same brain under extreme metabolic changes: alive and dead. Strikingly, the storage and loss moduli of the cerebrum increased by 26% and 60% within only three minutes post mortem and continued to increase by 40% and 103% within 45 minutes. Immediate post mortem stiffening displayed pronounced regional variations; it was largest in the corpus callosum and smallest in the brainstem. We postulate that post mortem stiffening is a manifestation of alterations in polarization, oxidation, perfusion, and metabolism immediately after death. Our results suggest that the stiffness of our brain-unlike any other organ-is a dynamic property that is highly sensitive to the metabolic environment. Our findings emphasize the importance of characterizing brain tissue in vivo and question the relevance of ex vivo brain tissue testing as a whole. Knowing the true stiffness of the living brain has important consequences in diagnosing neurological conditions, planning neurosurgical procedures, and modeling the brain's response to high impact loading.
I think questioning the relevance of ex vivo brain testing (i.e. not testing in life) as a whole, based on brain stiffness, is rather dubious. We should and can question the value and merits to these techniques but they should not be discarded.
When I started MS research, I was constantly told MS is a white matter condition. Here is an MS brain
You can all see the white matter (dark blue) lesions (within the green circle), but look and you can see relative lack of myelin loss in the grey matter but you can see areas where there is less myelin (within the red circles).These are probably Grey matter lesions. You just have to look with an open mind.
Labels: MRI, Pathology