Hemodynamic Analysis Of Intracranial Aneurysms On Curvature Parts Of Internal Carotid Artery,a Result Of High Dynamic Pressure And High Wall Shear Stress

Objective: Utilizing Computational Fluid Dynamics?CFD?softwares analysis formation of intracranial aneurysms on internal carotid artery curvature parts that based on rigid assumptions,and finding the relationships between hemodynamic factors and aneurysms formation.Methods: Collecting Digital Subtraction Angiography?DSA?image datas of Shijiazhuang first hospital neurosurgery patients with intracranial aneurysm?IA?who were admitted in 2013.12-2015.12.We slected 61 cases?a total of 68IAs?who were diagnosed of internal carotid artery non-bifurcation aneurysms as the experimental group,and we selected 20 cases out of these 61 patients whose contralateral blood vessels were normal as the control group.Using CFD softwares to reconstruct blood vessal models.Measuring the cambers of patient arteries of experimental group and the same parts' cambers of control group.Comparing two groups of blood vessels curvature whether there was statistical significance.We cut off the aneurysms and simulated to repair incision so that the patient arteries presented what they were before.Sampling from the simulated spout?make it bit 0?and the surrounding area?forward,backward,up,down,lateral,make them bit 1,2,3,4,5 respectively?,making the hemodynamic parameters a matching t test,and observing what parameters vary.The control group sampling and parameters were made in the same way.Observing whether the related parameters had statistical significance.Sampling on the top of the aneurysms?bit 6?and making a matching t test with bit 0,to make it clear what happened before and after the aneurysm onset.Making matching t tests respectively between experimental group and control group about 0-0 bit parameters,to find out the relationship between hemodynamic factors and IA formation.Results: We successfuliy reconstructed 61 cases of patients with a total of 68 aneurysms' 3 d-DSA imaging models based on the assumption of the rigid wall by CFD softwares.Measuring the curvature of IA parts of the blood vessels in experimental group?aexperimental?and the control group's vascular curvature in the same place?acontrol?.?experimental=131.21±14.85°,?control=149.68±9.34°,mean difference x=18.47°,making a matching t test,P<0.05,t=5.05,Experimental group's vascular curvature was higher than the control group.Making matching t tests among experimental group on dynamic pressure with bit 0 respectively.X₀=2.50±1.89 Pa,X₁=1.63±1.73 Pa,X₂=0.91±0.89 Pa,X₃=0.93±0.90 Pa,X₄=0.82±1.12 Pa,X₅=1.47±1.48 Pa,all P<0.05,dynamic pressure of bit 0 was higher than all the other bits.Making matching t tests among experimental group on total pressure with bit 0respectively.X₀=71.80±62.92 Pa,X₁=65.77±64.89 Pa,X₂=78.49±64.34 Pa,X₃=76.53±64.56 Pa,X₄=66.18±63.40 Pa,X₅=72.76±66.04 Pa,bit 4 P =0.2611 and bit 5 P =0.4503,there were no statistical significance,total pressure of bit 0was lower than bit 2 and bit 3 but higher than bit 1,P<0.05.Making matching t tests among experimental group on WSS with bit 0 respectively.X₀=1.55±0.97 Pa,X₁=1.24±0.67 Pa,X₂=0.93±0.47 Pa,X₃=0.95±0.67 Pa,X₄=0.75±0.52 Pa,X₅=0.95±0.67 Pa,all P<0.05,WSS of bit 0 was higher than all the other bits.Making matching t tests among experimental group on strain rate mag with bit 0 respectively.X₀=1023.96±510.05,X₁=896.41±441.38,X₂=692.05±333.65,X₃=707.39±455.87,X₄=564.77±371.93,X₅=777.45±447.55,all P<0.05,strain rate mag of bit 0 was higher than all the other bits.The same statistics processings were made in control group,dynamic pressure of 0 bit was lower than all the other bits?P<0.05?except bit4.P4=0.67,there was no statistical significance.Total pressure of bit 0 was higher than bit 1 and bit 4?P<0.05?,but lower than bit 2 and bit 3?P<0.05?,there was no statistical significance with bit 5,whose P =0.99.WSS of bit 0 is lower than bit 1 and bit 5?P<0.05?,there were no statistical significance with bit 2 bit 3 and bit4,P₂=0.8207,P₃=0.09,P₄=0.37.strain rate mag of bit 0was lower than bit 1?P<0.05?,there were no statistical significance with bit 2bit 3 bit4 and bit 5,P₂=0.85,P₃=0.11,P₄=0.29,P₅=0.06;Making matching t tests between samples resected before and after,bit 0 and bit 6 parameters were matched,total pressure : X₀=71.80±62.92 Pa,X₆=74.88±60.40 Pa,P=0.5404,there was no statistical significance;dynamic pressure:X₀=2.11±1.97 Pa,X₆=0.57±1.00 Pa,P <0.05,bit 0's was higher than bit 6;WSS:X₀=1.55±0.97 Pa,X₆=0.51±0.31 Pa,P <0.05,bit 0's was higher than bit6;Strant rate mag: X₀=1023.96±510.05,X₆=395.27±222.60,P <0.05,bit 0's was higher than bit 6.making a matching t test between experimental group and control group respectively on 0-0 bit parameters,results showed that the experimental group bit 0 a dynamic pressure,wall shear stress and strain rate mag were significantly higher than the control group,all P<0.05,there was no statistical significance about total pressure,P=0.3147.Conclusion:1.The originating site of IA is near where blood flow directly,it is the result of blood flow directly impact.2.There is a positive correlation between blood vessels curvature and IA formation,the greater curvature is,the higher possibility of the IA formation.3.High blood vessels curvature lead to a high dynamic pressure and a high wall shear stress area,these two forces combination may be the hemodynamics factors of IA formation.4.The higher strain rate mag is,the greater possibility of the IA formation.5.Once IA formed,there was no obvious change in total pressure,while the dynamic stress,wall shear stress and strain rate mag all tended to decrease.The formation of IA is a voluntary reduction in active process of local wall high stress.