Gels G C, Stewart H F, Smith S W
Med Instrum. 1987 Apr;21(2):66-74.
A rapid, inexpensive, portable technique has been developed for the qualitative and semiquantitative evaluation of in vitro flow characteristics through prosthetic heart valves. The technique combines a cardiac pulse duplicator and any diagnostic, linear sequential array, ultrasonic imaging system. The pulse duplicator has been modified to include an acoustically transparent aortic section which contains the prosthetic valve to be evaluated. The acoustically transparent section is fabricated from Rho-c rubber and enables direct flow-imaging for several centimeters on both sides of the prosthesis. Aerated tap water is used as a contrast medium. Forward and reverse flow, laminar flow complex eddy patterns, regurgitation, and jets are easily observed in real time over a wide field of view. Time-exposure photography of sequential images and subsequent off-line calculations enable point-by-point determinations of flow velocities. This work allowed preliminary evaluations of four cardiac valves: Bjork-Shiley, St. Jude, caged disk, and Starr-Edwards.
已开发出一种快速、廉价、便携的技术，用于对通过人工心脏瓣膜的体外流动特性进行定性和半定量评估。该技术将心脏脉冲复制器与任何诊断性线性序列阵列超声成像系统相结合。对脉冲复制器进行了改进，使其包括一个声学透明的主动脉部分，其中包含待评估的人工瓣膜。声学透明部分由Rho-c橡胶制成，可在假体两侧几厘米范围内进行直接血流成像。曝气自来水用作造影剂。在广阔的视野范围内，可以轻松实时观察正向和反向流动、层流复杂涡旋模式、反流和射流。对序列图像进行时间曝光摄影并随后进行离线计算，可以逐点确定流速。这项工作对四种心脏瓣膜进行了初步评估： Bjork-Shiley瓣、圣犹达瓣、笼球瓣和斯塔尔-爱德华兹瓣。
