Hive Activity
Current Research and what I've been doing so far...
I have been doing research in the field of stroke imaging. I promise you it's not as lame as it sounds! Also, it's interesting once you realise what it's about.
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Fairy Tale Introduction:
Once upon a time, there is a blood vessel. This blood vessel is very naughty. It eats and eats and eats. All those fatty foods accumulate in the vessel wall. The wall gets inflamed. A plaque starts to form within the walls. However, this also means that the luminal space (space allowed for blood to pass through in the vessel) is also significantly reduced. Blood is vital for everyone, especially cells, since it carries valuable things such as sugars and oxygen. If cells don't have enough of these things, they malfunction. Worse still, they die.
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More importantly, this naughty blood vessel is located in the brain. As we know, brain cells are different from other cells. Brain cells need a lot of food since they are always working #CleverClogs. If they don't have enough food, they die very easily as well. Once brain cells die, they cannot regrow. Also, the brain will be limited in what it can do, unless (via a mechanism called neuroplasticity) other cells decide to take up the deceased's role.
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The 'blockade' of a blood vessel located in the brain is called stroke. Technically, if the 'blockade' lasts for less than 24 hours, meaning that everything reverts to normal by that time, it is called a 'Transient Ischaemic Attack' (TIA). Anything beyond that time limit is an ischaemic stroke. 'Ischaemic' means not having enough blood, leading to manifest cellular changes.
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Why did you quote the word blockade?
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That's because it's a really vague word. What do we mean by blockade? In medicine, there are various extents something can be blocked. In my research, I use the two words: (1) Stenosis, meaning narrowing, and (2) Occlusion, meaning total blockade. We use the NASCET Criteria [1] which divide degrees of stenoses into different categories.
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Ok...so what is that you actually do...?
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We develop a huge database using a cohort of over a thousand patients. This database contains data regarding the number and degrees of stenoses (obviously including occlusions) of MOST arteries in the brain. I use the word 'most' because there are some which can hardly be observed by modern imaging techniques. To do so, we use Magnetic Resonance Angiography (MRA), which is a branch of MRI and focuses on the health of blood vessels. Furthermore, the database includes clinical data (such as blood pressure and blood glucose levels) and data of 'manifest ischaemic lesions'. As explored above, brain cells experience damage when they don't get enough food. They show changes. Imaging can help us in seeing them. We use a type of MRI called DWI (diffusion weighted imaging) to identify areas of manifested ischaemia. Such lesion data include the sizes and locations and numbers of the lesions.
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So basically, I spent a year reading scans. It wasn't easy since I had to know the precise anatomy of blood vessels (note that everyone's anatomy is different, more or less) and certain confounding variables, i.e. it looks like a stenosis but is actually something else.
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What directions does this research go?
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Well, this is rather controversial. Generally, we wish to explore the relationships of blood pressure, blood glucose and vessel health. We also want to calculate survival rates for patients with lesions at different parts of the brain. In addition, I propose novel research directions:
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(1) Perfusion Studies - meaning that I want to see how good the blood supply is to the entire brain; this comes from two places:
(a) if a patient has an acute event, the blockade is sudden and does not allow much time for adaptation, i.e. the development of new vessels for compensation - does this mean such patients have poorer survival rates (i.e. prognosis)?
(b) What if the plaque moves in time and space? There is a concept in neurology called 'artery-artery embolisation'. It means that the thrombus, the inciting lesion which encroaches upon the vascular lumen in the first place, can detach from the vessel wall in virtue of the physical forces acting upon it by the roaring, torrential flow of blood. How can artery-artery embolisation affect perfusion? Also, does this phenomenon vary in impact depending on which vessel it commences?
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(2) Posterior Circulation - the cerebral circulation has two parts: anterior and posterior. The posterior circulation includes the following- vertebral, posterior cerebral, cerebellar (superior, anterior inferior, posterior inferior), basilar, posterior communicating and subclavian arteries; I want to explore the following:
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(a) Whether collateralisation efforts differ between anterior and posterior circulations and how (collateralisation is described above - the construction of new vessels following occlusion);
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(b) Anatomical Variants that can impact on prognosis and survival. This includes the hypoplasia (smaller than normal) of vertebral arteries (this condition is more common than you think - over 40% [2]), vertebrobasilar dolichoectasia (the abnormal curvature of the vertebral and basilar arteries) and Artery of Percheron (very weird phenomenon but lethal) [3]
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Post-submission blues:
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So far I've written an article about this project and got an academic prize (yay!) and submitted articles to research reviews but I'm not hopeful. Hope I get an acceptance instead of a rejection - life of an academic...
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Reference List:
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[1] North American Symptomatic Carotid Endarterectomy Trial Collaborators. (1991). Beneficial Effect of Carotid Endarterectomy in Symptomatic Patients with High-Grade Carotid Stenosis. New England Journal of Medicine 325(7), 445-453. https://doi.org/10.1056/nejm199108153250701
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[2] Peterson C., Phillips L., Linden A., & Hsu W. (2010). Vertebral Artery Hypoplasia: Prevalence and Reliability of Identifying and Grading its Severity on Magnetic Resonance Imaging Scans. Journal Of Manipulative And Physiological Therapeutics, 33(3), 207-211. https://doi.org/10.1016/j.jmpt.2010.01.012
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[3] Sandvig A., Lundberg S. & Neuwirth J. [2017]. Artery of Percheron infarction: a case report. J Med Case Reports 11, 221. https://doi.org/10.1186/s13256-017-1375-3
