Yanjing Han1, Qingqing Yang2, Zeran Yang1, Jun Xia2, Tianhao Su1, Jianan Yu1, Long Jin3, Aike Qiao4. 1. Department of Interventional Radiography, Beijing Friendship Hospital, Capital Medical University, Beijing, People's Republic of China. 2. College of Life Science and Bioengineering, Beijing University of Technology, Beijing, People's Republic of China. 3. Department of Interventional Radiography, Beijing Friendship Hospital, Capital Medical University, Beijing, People's Republic of China. Electronic address: longejin@163.com. 4. College of Life Science and Bioengineering, Beijing University of Technology, Beijing, People's Republic of China. Electronic address: qak@bjut.edu.cn.
Abstract
OBJECTIVE: To investigate the relationships between upstream venous sinus stenosis and pulsatile tinnitus (PT), and to assess the correlation with diverticulum growth and the effectiveness of stent implantation. METHODS: Patient-specific geometric models were constructed using computed tomography venography images from a patient with PT, with sigmoid sinus diverticulum, and with upstream transverse sinus stenosis, in whom stenting of the upstream sinus stenosis alone achieved complete remission of PT. Computational fluid dynamics simulation based on this patient-specific geometry was performed using commercially available finite element software (ANSYS-14) to qualitatively and quantitatively compare the flow velocity, flow rate, velocity vector, pressure, vorticity, and wall shear stress on the affected side transverse and sigmoid sinuses, before and after stent implantation. RESULTS: Stenting improved the flow direction and magnitude. After stenting, the flow pattern became smoother and more regular. High-speed blood flow at the level of the diverticulum neck was confined to a smaller area, and its direction changed from approximately perpendicular to the diverticular dome to the distal side of the diverticular neck. The diverticulum showed obvious flow reduction, with decreases of 80.7%, 68.7%, 96.1%, and 91.3% in peak velocity, inflow rate, pressure gradient, and peak vorticity, respectively. The abnormally low wall shear stress at the dome of diverticulum was eliminated. CONCLUSIONS: Our findings strongly support a major role of diverticulum stenosis before in PT development and suggest that such stenosis is a causative factor of diverticulum growth. They also confirm the effectiveness of stent implantation for the treatment of PT.
OBJECTIVE: To investigate the relationships between upstream venous sinus stenosis and pulsatile tinnitus (PT), and to assess the correlation with diverticulum growth and the effectiveness of stent implantation. METHODS:Patient-specific geometric models were constructed using computed tomography venography images from a patient with PT, with sigmoid sinus diverticulum, and with upstream transverse sinus stenosis, in whom stenting of the upstream sinus stenosis alone achieved complete remission of PT. Computational fluid dynamics simulation based on this patient-specific geometry was performed using commercially available finite element software (ANSYS-14) to qualitatively and quantitatively compare the flow velocity, flow rate, velocity vector, pressure, vorticity, and wall shear stress on the affected side transverse and sigmoid sinuses, before and after stent implantation. RESULTS: Stenting improved the flow direction and magnitude. After stenting, the flow pattern became smoother and more regular. High-speed blood flow at the level of the diverticulum neck was confined to a smaller area, and its direction changed from approximately perpendicular to the diverticular dome to the distal side of the diverticular neck. The diverticulum showed obvious flow reduction, with decreases of 80.7%, 68.7%, 96.1%, and 91.3% in peak velocity, inflow rate, pressure gradient, and peak vorticity, respectively. The abnormally low wall shear stress at the dome of diverticulum was eliminated. CONCLUSIONS: Our findings strongly support a major role of diverticulum stenosis before in PT development and suggest that such stenosis is a causative factor of diverticulum growth. They also confirm the effectiveness of stent implantation for the treatment of PT.