Numerical Study On The Influence Of Transverse Sinus Stenosis And High Jugular Bulb On Hemodynamics Of Sigmoid Sinus And Internal Jugular Vein

Pulsating tinnitus is one of the common symptoms of otology,long-term existence seriously affects the quality of life of patients,and may lead to depression and even suicide.The causes of pulsatile tinnitus are complex and diverse,and abnormalities in intravascular hemodynamics caused by transverse sinus stenosis and high jugular bulb are common causes of venous pulsatile tinnitus.However,at present,the influence of transverse sinus stenosis and high jugular bulb on the hemodynamics of the sigmoid sinus and internal jugular vein is still unclear.In order to explore the hemodynamic changes caused by transverse sinus stenosis and high jugular bulb,the main research contents of this paper are as follows:（1）The computational fluid dynamics method was used to study the influence of transverse sinus stenosis on the hemodynamics of sigmoid sinus.First,normal vascular models were constructed based on clinical patient data,followed by transverse sinus vascular models with stenosis of 25%,50%,and 75%.Secondly,the computational fluid dynamics method was used to study the hemodynamics of the transverse sinus with different stenosis degrees on the sigmoid sinus.Finally,PIV experiments and 4D Flow MRI experiments were used to verify the accuracy of the numerical simulation results.（2）The computational fluid dynamics method was used to study the influence of jugular bulb height on the hemodynamics of internal jugular vein.Firstly,the internal jugular vein model with ball height of 0.5cm and 1.0cm was established on the normal vessel model.Secondly,the effect of different jugular bulb height on the hemodynamics of internal jugular vein was studied by computational fluid dynamics method.Finally,4D Flow MRI experiment was used to verify the accuracy of numerical simulation results.（3）The effect of transverse sinus stenosis combined with high jugular bulb on sigmoid sinus hemodynamics was studied by computational fluid dynamics method.First,on the basis of normal vascular model,12 types of transverse sinus with different stenosis degree and different bulb height internal jugular vein models were established.Secondly,the effect of transverse sinus stenosis combined with high jugular bulb on sigmoid sinus hemodynamics was investigated by CFD method.Finally,4D Flow MRI experiment was used to verify the accuracy of numerical simulation results.The research results and conclusions are as follows:（1）Compared with the numerical simulation results in the PIV experiment and 4D Flow MRI experiment,the hemodynamic changes of the sigmoid sinus and internal jugular vein had a better consistency,which qualitatively verifyed the accuracy of the numerical simulation results.（2）With the deepening of transverse sinus stenosis,the maximum flow velocity at the transverse sinus stenosis increased by 37.31%,79.10%,277.61%,respectively,and the maximum flow velocity in the area of sigmoid sinus wall abnormality increased by28.1%,63.2%,200%,respectively.The maximum wall pressure in the area of sigmoidal sinus wall abnormality increased by 7.85%,20.91%and 78.2%,respectively,and the maximum wall shear force（WSS）in the area of sigmoidal sinus wall abnormality increased by 19.8%,73.7%and 388.47%,respectively.The mean vorticity(V_avgV)of sigmoid sinus increased by 21.86%,45.97%and 149.1%,respectively.（3）With the increase of the height of the jugular bulb,a unique spiral blood flow pattern was formed in the proximal part of the internal jugular vein.The V_avgV of the internal jugular vein increased from 296 s^-1 to 325.68 s^-1,300.95 s^-1,the maximum wall pressure in the high jugular bulb area increased from 8.36 Pa to 87.67 Pa,86.78 Pa,and the maximum WSS in the high jugular bulb area increased from 1.51 Pa to 6.36 Pa and7.59 Pa.When the height of the jugular bulb rised to 0.5 cm,the hemodynamics of the internal jugular vein changed significantly.If it continued to increase,it would not aggravate the influence on the wall pressure and WSS of the internal jugular vein,suggesting that the influence of the height of the jugular vein bulb on pulsating tinnitus should be considered in clinical treatment.（4）At the same degree of transverse sinus stenosis,the presence of high jugular bulb had no significant effect on blood flow velocity,maximum wall pressure,maximum WSS and V_avgV of sigmoid sinus.When both transverse sinus stenosis and high jugular bulb were present,high jugular bulb had no significant effect on hemodynamics in sigmoid sinus.In the clinical treatment of patients with transverse sinus stenosis,if there was no perijugular bulbous bone wall loss,it was suggested that high jugular bulbous should not be considered as the synergistic cause.In this article,through exploring the transverse sinus stenosis degree and jugular bulb height on the influence of the sigmoid sinus and internal jugular venous hemodynamics,illuminated the transverse sinus stenosis and high jugular bulb to the sigmoid sinus and the influence law of internal jugular venous hemodynamics,the clinical treatment of transverse sinus stenosis and high jugular bulb caused by pulsatile tinnitus provided the important theory instruction value.