目的:脉冲同步耳鸣(PST)与中心静脉流出道(CVOT)的多种解剖学变异有关,包括乙状窦(SS)裂开和憩室。这项研究调查了流动湍流,压力,和沿CVOT的壁剪应力,并提出了导致SS开裂和PST的机制。
方法:案例系列。
方法:高等教育中心。
方法:从3例单侧PST患者的计算机断层扫描扫描重建静脉模型。获得每个患者的两个模型:有症状侧和对侧无症状侧。使用启用湍流模型的商业流量求解器通过模型模拟心动周期内的脉动血流。通过横向和SS接头的流体流动进行了分析,以观察速度,压力,湍流动能(TKE),以及模拟心动周期内的剪切应力。
结果:在SS憩室存在的情况下,症状侧的流体流动显示涡度增加。在有症状的一侧观察到在心动周期后具有周期性的较高TKE,如果存在SS憩室,则观察到急剧增加。在血管最窄的部分附近,剪切应力最高。对于所有3例患者,在SS横向交界处的症状侧观察到压力较低。
结论:PST中通过CVOT的血流的计算流体动力学模型表明,低压可能是开裂的原因,和耳鸣可能由TKE的周期性增加引起。
OBJECTIVE: Pulse-synchronous tinnitus (PST) has been linked to multiple anatomical variants of the central venous outflow tract (CVOT) including sigmoid sinus (SS) dehiscence and diverticulum. This study investigates flow turbulence, pressure, and wall shear stress along the CVOT and proposes a mechanism that results in SS dehiscence and PST.
METHODS: Case series.
METHODS: Tertiary Academic Center.
METHODS: Venous models were reconstructed from computed tomography scans of 3 patients with unilateral PST. Two models for each patient are obtained: a symptomatic and contralateral asymptomatic side. A turbulent model-enabled commercial flow solver was used to simulate the pulsatile blood flow over the cardiac cycle through the models. Fluid flow through the transverse and SS junction was analyzed to observe the velocity, pressure, turbulent kinetic energy (TKE), and shear stress over a simulated cardiac cycle.
RESULTS: Fluid flow on the symptomatic side showed increased vorticity in the presence of an SS diverticulum. Higher TKE with periodicity following the cardiac cycle was observed on the symptomatic side, and a sharp increase was observed if SS diverticulum was present. Shear stress was highest near the narrowest segments of the vessel. Pressure was observed to be lower on the symptomatic side at the transverse-SS junction for all 3 patients.
CONCLUSIONS: Computational fluid dynamics modeling of blood flow through the CVOT in PST suggests that low pressure may be the cause of dehiscence, and tinnitus may result from periodic increases in TKE.