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Disruption to blood flow anywhere in the body can result in damage or death of cells. The brain is particularly vulnerable because its correct and continued function relies on a healthy network of arteries, veins and capillary blood vessels. With stroke being a major cause of death worldwide (up to 121 per 100,000 people, according to the World Health Organization1), along with dementia2, where vascular brain changes are now linked to Alzheimer’s disease3, the ability to accurately model blood flow in the brain is an important tool to assist diagnosis, understanding and treatment of various cerebral blood vessel disorders, along with aiding brain surgical procedures.
Partially supported by the “Study on the Four-dimensional Calculation Model of Minute Cranial Nerves and Blood Vessels” JSPS’s Grants-in-Aid for Scientific Research 25280104, Professor Hiroshi Oyama (School of Medicine, The University of Tokyo) and Shinji Shibano (Altair Japan), recently published “Cerebral Blood Flow Simulation Procedures Based on Measurement Shapes of the Brain and Main Blood Vessels (Part 1)”. This considers the development of whole-brain blood flow model, along with analysis examples.
A meaningful model of the cerebral blood perfusion process that considers the full capillary network is known to be complex and difficult. The Oyama and Shibano study makes use of the measurement data of blood perfusion inside the brain using the 3D shape of the brain, the 3D shape of the main blood vessels (to fourth branch) acquired from MRI and CT. It also assumes the smaller vessels and capillary network form the cerebral equivalent osmotic resistance.
HyperMesh was used to resolve two major issues relating to creating the overall geometry: penetrating surfaces of 3D brain and 3D blood vessels, and outflow at the end of blood vessels. As a result, a continuous surface was generated using 3D brain shape and the 3D blood vessel shape. Since this surface is closed, the volume could be determined automatically, and a model of blood perfusion inside the brain could then be created.
AcuSolve was chosen because it overcame known problems associated with the finite volume method (FVM) and the high computation demands of FEM-CFD in terms of analysis speed and memory usage.
The model input data (arterial pressures, heart rate; calculated osmotic resistance; venous flow rates) was for the case of a cerebral disorder is present in the left side of the brain. The analysis results clearly show that the blood circulation is insufficient on the left side of the brain.
The preliminary stages of this study show that the modeling procedure successfully represented the cerebral blood flow variation with time and that changes in blood perfusion inside the brain also enabled visualization of cerebral disorders.
Continuation of the work aims to implement “Digital Twins” in brain science: disorder study model to assist Model-Based Drug Development (MBDD) and time-related data of blood flow and pressure in the main blood vessels. Together these will aid doctors’ understanding of disorders such as cerebral infarction, vascular dementia, along with assisting surgeons with procedures such as vascular anastomosis.
Learn more by downloading the full white paper: Cerebral Blood Flow Simulation Procedures Based on Measurement Shapes of the Brain and Main Blood Vessels
1 World Health Organization, “The Top 10 Causes of Death” http://www.who.int/mediacentre/factsheets/fs310/en/index1.html
2 Alzheimer Europe, “The Prevalence of Dementia in Europe: Country comparison (2013)” http://www.alzheimer-europe.org/Policy-in-Practice2/Country-comparisons
3 Alzheimer’s Association (USA), “Vascular Dementia” https://alz.org/dementia/vascular-dementia-symptoms.asp