超声联合3D打印技术体外模拟二尖瓣狭窄的血流动力学特征

目的以超声为数据源,应用3D打印技术联合MCS制作动态的狭窄二尖瓣模型,并于体外再现二尖瓣狭窄时瓣膜口的血流动力学特征。方法选取二尖瓣狭窄患者12例,收集患者在体状态下瓣口峰值流速(Emax)、峰值压差(Emax)、平均流速(Emean)、平均压差(PGmean),并应用压差半降法评估瓣口面积(MVAPHT)。另选取因其他疾病就诊的8例患者作为对照组。后行经食管三维超声心动图检查,以获取二尖瓣三维图像。将三维图像以DICOM格式导出至后处理软件Mimics、3-matic中,经阈值分割、光滑等处理获取二尖瓣数字模型。后应用硅胶铸模方法制作柔软的硅胶二尖瓣模型。于体外构建模拟循环系统装置,将二尖瓣模型置于装置中,再次测量上述血流动力学参数,评估瓣膜狭窄程度。对比体内外测量所得结果,P≤0.05为差异有统计学意义。结果两组患者对比在体与体外模型中测得的血流动力学参数差异不具有统计学意义;12例二尖瓣狭窄患者中,10例患者在体评估瓣膜狭窄程度与体外模型评估结果一致。结论应用3D打印技术,结合体外模拟循环系统可制作动态二尖瓣狭窄模型,且准确度较高。对二尖瓣狭窄血流动力学特征的精确复制可为体外术式模拟、手术方案的选择提供实验基础,辅助临床诊疗。

Feasibility Study of Using Ultrasound Combined With 3D Printing Technology to Simulate Hemodynamic Characteristics of Mitral Valve Stenosis in Vitro

Objective Based on ultrasound data source,3 D printing technology combined with MCS was applied to produce dynamic mitral stenosis model,and to reproduce hemodynamic characteristics of valve orifice during mitral stenosis in vitro.Methods 12 patients with mitral stenosis were selected to collect Emax,Emax,Emean and PGmean in body condition,and to evaluate the valve orifice area with the pressure half time method.Another 8 patients with other diseases were selected as the control group.Three-dimensional transesophageal echocardiography was performed to obtain volume image of mitral valve.3 D volume images were then exported to Mimics and 3-matic software in DICOM format,and digital mitral valve models were obtained through threshold segmentation,smoothing and other postprocessing.Flexible mitral valve model was made by silica gel casting.Mock circulatory system was constructed in vitro,and the mitral valve model was placed in the device to measure the above hemodynamic parameters again and evaluate the degree of valve stenosis.Comparing results in vitro with that in vivo,P≤0.05 was considered statistically significant.Results The hemodynamic differences between the two groups were not statistically significant.Among the 12 patients with mitral stenosis,10 patients were evaluated in vitro model with the same results tested in vivo.Conclusions The dynamic mitral stenosis model can be made by using 3 D printing technology with high accuracy.Accurate replication of hemodynamic characteristics of mitral valve stenosis can provide experimental basis for in vitro simulation and selection of surgical procedures,and assist clinical diagnosis and treatment.