GEOMETRICAL MODELS OF VERTEBRAL ARTERIES AND NUMERICAL SIMULATIONS OF THE BLOOD FLOW THROUGH THEM

摘要

Vertebral arteries are a system of two blood vessels through which blood is carried to the rear region of the brain. This region of the human body has to be very well supplied with blood, without any breaks or deficiencies in the blood flow. Blood is delivered to the brain through carotid arteries as well. All these arteries are connected to the circle of Willis, which has to fulfill all demands of the human brain as far as the blood flow is concerned. However, vertebral arteries due to their position and shape are a special kind of blood vessels. They originate at various distances from the aortic ostium, may branch off at different angles, have various length, inner diameter and spatial shape. Three different geometries of vertebral arteries, which most frequently occur in the human body structure, have been chosen, and for each twenty five various combinations of artery inner diameters have been used to generate 3D models of these arteries. For seventy five different models thus created, the numerical simulations have been performed. The results obtained have indicated explicitly that differences in the flow and instantaneous velocity values in vertebral arteries and in the point they join to form the basilar artery do not result from pathological changes in the artery system, but may follow from physical phenomena that occur in arteries as a consequence of the pulsating character of the flow and the unique geometry, which is related to the individual human anatomical structure.