基于CT图像胸主动脉夹层与正常胸主动脉内血流动力学模拟对比分析

目的通过对基于CT图像的血流动力学数值模拟获得的患有降主动脉夹层与正常胸主动脉内的血流动力学参数的比较,分析主动脉夹层内血液流动状态与动脉夹层疾病的关系,为阐明主动脉夹层疾病的发病机制提供理论依据。方法患者A为46岁男性,胸主动脉正常;患者B为33岁女性,患有通腔型降主动脉夹层,即通腔形式的DeBakeyⅢ型主动脉夹层。CT图像为DICOM格式,层间距为0.5mm,每片图像的平面分辨率为512×512,像素大小为0.5mm。应用医学图像后处理软件对通过临床获得的CT二维医学图像数据进行处理重构,得到正常和患有降主动脉夹层的胸主动脉三维立体模型并转化为可用于模拟计算的计算机辅助设计（CAD）模型。应用计算流体力学（CFD）软件模拟胸主动脉内血流情况,获得相关血流动力学参数。结果计算出胸主动脉在心动周期内不同时刻的血流动力学参数。结论在心动周期内患有动脉夹层胸主动脉内血流情况较正常胸主动脉内血流情况更为复杂,表现为管壁压力变化较大、夹层开口处出现多个漩涡等现象,表明主动脉夹层内复杂血流情况与主动脉夹层疾病的发病机制存在一定的关系。

Comparison of blood flow dynamics in thoracic aortic dissection and normal aortic based on CT images

Objective To study the comparison of blood flow in the aortic dissection and thoracic aortic,and provide theoretical basis for clarifying the pathogenesis of aortic dissection disease through the hemodynamic parameters of aortic dissection based on CT images.Methods Patient A,male,46-year-old,with normal thoracic aortic;patient B,female,33-year-old,with cavity form of DeBakey Ⅲ aortic dissection were enrolled.CT images was DICOM format,layer distance 0.5 mm,plane resolution 512 × 512 and pixel size 0.5 mm.The medical image post-processing software was applied to reconstruct the clinical two-dimensional CT reconstruction of medical images,and the three-dimensional model for simulation of the computer aided design（CAD） model was obtained.The computational fluid dynamics（CFD） software was applied to simulate the blood flow within the thoracic aorta,and the relevant hemodynamic parameters were obtained.Results The hemodynamic parameters of thoracic aorta at different time during a cardiac cycle were calculated.Conclusion The blood flow in aortic dissection during the cardiac cycle is complex,which shows as the large changes in wall stress,multiple vortex phenomena at the openings,thus it demonstrates there is a certain relationship between the complex blood current pattern in aortic dissection and the pathogenesis of aortic dissection disease.