【作者】 郭立；

【导师】 杨达宽； 袁曙光； 闫东； 杨绍军； 王家平；

【作者基本信息】 昆明医学院 ， 外科学， 2010， 博士

【摘要】 目的：通过体外、体内实验来验证磁共振相位对比法（phase contrast magnetic resonance imaging, PCMRI）测量主动脉血流速度的准确性；并在此基础上,应用该法建立国人的胸主动脉平均血流速度和平均血流量的正常参考值,为临床诊断提出参考,为今后主动脉血液动力学的研究奠定基础。材料与方法：第一部分：（1）建立直形血管模型。应用PCMRI对模型玻璃管内流速为±100、±80、±60、±40、±20、0cm/s的流体进行测量,并与流速计的结果进行比较,观察两者的关系,获得PCMRI法的校正公式；（2）PCMRI法测量胸主动脉准确性的体外实验：①建立主动脉体外模型。PCMRI法中最大编码速度分别设定为90、120、150、180cm/s,并对U型玻管不同部位（U₁、U₂、U₃段）内流速为100cm/s的流体进行测量,选择最佳的最大编码速度；②最大编码速度定为150cm/s,应用PCMRI法对模型中不同部位（U₁、U₂、U₃段）内流速为1OOcm/s、80cm/s、60cm/s、40cm/s、20cm/s、Ocm/s的流体进行测量,观察该法测量流速的准确性；③最大编码速度定为150cm/s,应用PCMRI法对模型中不同部位（U₁、U₂、U₃段）内流速为-1OOcm/s、-80cm/s、-60cm/s、-40cm/s、-20cm/s、-0cm/s的流体进行测量,观察该法测量主动脉反流速度的准确性。第二部分：（1）分别对31例健康志愿者和21例心血管病患者采用PCMRI法和UCG流速法测量升主动脉心动周期内的血流量,并与4D-MRI心室体积测量法所得的每搏输出量进行比较,观察两种方法测量主动脉血流速度的准确性；（2）采用PC MRI法和UCG流速法分别重复对9例和11例正常志愿者升主动脉心动周期内的血流量进行测量,对两次测量结果进行比较,观察两种流速测量法的可重复性。第三部分：对136例健康志愿者采用PCMRI法测量升主动脉、胸降主动脉的平均血流量和平均血流速度,并按性别（男、女）和年龄（20～39、40～59、60～80岁）分组经行研究。结果：第一部分：（1）直形血管模型中,磁共振PC MRI法测量流速与实际流速间具有极佳的相关性（r=0.99）,校正公式为：y=0.971x+0.494。（2）PC MRI法测量胸主动脉准确性的体外实验结果：①最大编码速度为90cm/s时,PC MRI法测量值与流速计测量值存在显著性差异（P<0.05）；最大编码速度为120、150、180cm/s时,PC MRI法测量值与流速计测量值无显著性差异。②PC MRI法能准确测量主动脉模型内正向和反向的不同流速的流体（P>0.05）。第二部分：MRI 4D心室体积法、PC MRI流速法测得的结果具有良好的相关性（正常人组：r4D:PC=0.917;心血管患者组：r4D:PC=0.895）,两者测量值无显著性差异（正常人组P>0.05,心血管患者组：P>0.05）；PC MRI流速法测量具有较高的重复性（P=0.872, r=0.950）. MRI 4D心室体积法和UCG流速法测得的结果具有一定的相关性（正常人组：r4D:UCG=0.737,心血管患者组：r4D:UCG=0.633）,但两者测量值存在显著性差异（正常人组P<0.05,心血管患者组P<0.05）；UCG流速法具有一定的重复性（P=0.721,r=0.753）。第三部分：（1）升主动脉和降主动脉的管径及平均血流量存在性别差异（P<0.05）,男性高于女性；升主动脉和降主动脉的平均血流速度无性别差异（P>0.05）。（2）升主动脉的管径、平均血流量、平均血流速度在不同年龄中存在差异（P<0.05）。随着年龄的增长,升、降主动脉的管径逐步增粗,平均血流量、平均血流速度逐步减小。（3）女性升、降主主动脉管径变化率高于男性（升主动脉：4.73%,2.01%；降主动脉：0.58%,0.51%）；随着年龄的增长,升、降主动脉管径管径变化率呈逐渐下降的趋势（升主动脉：5.20%、3.82%、2.31%；降主动脉：0.81%、0.53%、0.03%）。结论：（1） PC MRI法测量胸主动脉血流参数具有安全、无创、快速、准确、信息量大、可重复性高,优于UCG,可作为胸主动脉血流测定的“金标准”。（2）升主动脉和降主动脉的管径及平均血流量存在年龄、性别差异。升主动脉和降主动脉的血流速度不存在性别差异,但存在年龄差异。（3）不同年龄段、不同性别的胸主动脉平均血流量、平均血流速度的参考值范围：20～39岁男性平均血流量为5.56～7.13 L/min,平均血流速度为9.45～27.63 cm/s；20～39岁女性平均血流量为4.98～6.27 L/min,平均血流速度为8.48～24.30 cm/s。40～59岁男性平均血流量为5.42～6.17 L/min,平均血流速度为9.21～23.91 cm/s;40～59岁女性平均血流量为4.82～5.37 L/min,平均血流速度为8.19～20.81cm/s；60～80岁男性平均血流量为5.59～6.16 L/min,平均血流速度为9.50～23.87cm/s；60～80岁女性平均血流量为4.68～5.15L/min,平均血流速度为7.96～19.96cm/s。（4）不同年龄段、不同性别的胸降主动脉平均血流量、平均血流速度的参考值范围：20～39岁男性平均血流量为4.72～6.06L/mim,平均血流速度为8.02～23.4cm/s；20～39岁女性平均血流量为4.23～5.32L/min,平均血流速度为7.19-20.62cm/s。40～59岁男性平均血流量为4.60～5.24L/min,平均血流速度为7.82～20.31cm/s；40～59岁女性平均血流量为4.09～4.56L/min,平均血流速度为6.95～17.67cm/s；60～80岁男性平均血流量为4.75～5.23L/min,平均血流速度为8.07～20.27cm/s；60～80岁女性平均血流量为3.97～4.37L/min,平均血流速度为6.75-16.93cm/s；更多还原

【Abstract】 [Abstract]Objective:In vitro, in vivo experiments to test the accuracy of aortic blood flow velocity measured by magnetic resonance phase contrast (PC MRI). On this basis, we use this method to establish the normal reference values of the thoracic aorta blood flow velocity and blood flow, which is very useful for clinical use and future aortic hemodynamic study.Methods:Part I:(1) We applied the method of PC MRI on the model of straight vessel to measured the different fluid velocity(+100%±80%±60%±40%±20%Ocm/s),compare the results with tachometer and get the correction formula of PC MRI method; (2) The accuracy of thoracic aorta in vitro were measured by PC MRI:①With different VEC(90,120,150,180cm/s), we applied the method of PC MRI on the model of aorta to measured the fluid velocity(100cm/s) in the different parts of U-type glass tube (U1, U2, U3), compare the results with tachometer and get the best VEC value;②With VEC 150cm/s, we applied the method of PC MRI on the model of aorta to measured the fluid velocity(100cm/s,80cm/s,60cm/s,40cm/s, 20cm/s, Ocm/s) of the different parts of U-type glass tube (U1, U2, U3), compare the results with tachometer and observe the accuracy of this method;③With VEC 150cm/s, we applied the method of PC MRI on the model of aorta to measured the fluid velocity(-100cm/s,-80cm/s,-60cm/s,-40cm/s,-20cm/s,-Ocm/s) of the different parts of U-type glass tube (U1, U2, U3), compare the results with tachometer and observe the accuracy of aortic regurgitation.PartⅡ:(1) We applied the method of PC MRI and the method of UCG respectively to measured the ascending aortic blood flow (31 healthy volunteers and 21 patients) with cardiovascular diseases within the cardiac cycle, results compared with the stroke volumes which were obtained by the method of 4D-MRI ventricular volume measurements, compared the measurement’s accuracy of these methods. (2) We applied the method of PC MRI and the method of UCG to measured the ascending aortic blood flow of the healthy volunteers (PC MRI 9 cases, UCG 11 cases) twice, compared the first results with the second, observe the repeatability of these methods.PartⅢ:The mean blood flow volume and mean flow velocity of the ascending aorta and thoracic descending aorta were measured in 136 healthy volunteers with PC MRI. These data were analyzed.Results:PartⅠ:(1) The result have excellent correlation between PC MRI and tachometer (r=0.99) in straight vessel model. The correction formula:y= 0.97lx +0.494. (2) The accuracy of thoracic aorta in vitro were measured by PC MRI:①With VEC 90cm/s, there have significant differences between the result measured by PC MRI with the value of tachometer(P<0.05). With VEC were different (120,150, 180cm/s), there have no significant differences between the result measured by PC MRI with the value of tachometer(P> 0.05).②ith VEC 150cm/s, there have no significant differences between the velocity (±100,±80,±60,±40,±20, 0cm/s)and direction(forward, reverse) measured by PC MRI with the value of tachometer in (P> 0.05).PartⅡ:The result were measured by the method of PC MRI have excellent correlation with the method of 4D-MRI ventricular volume measurements (normal group:r4D:pc= 0.917; cardiovascular patient groups:Uo-, pc= 0.895). There has no significance between these two methods (normal group:P> 0.05, cardiovascular patient groups:P> 0.05). There have high repeatability in velocity measured by the method of PC MRI (P= 0.872, r= 0.950).The result were measured by the method of UCG have correlation with the method of 4D-MRI ventricular volume measurements (normal group:r4D:UCG= 0.737; cardiovascular patient groups:r4D:ucg= 0.633). There have significance between these two methods (normal group:P<0.05, cardiovascular patient groups:P<0.05). There have general repeatability in velocity measured by the method of UCG (P= 0.721, r= 0.753).Part III:(1) Males were larger than females in the values of diameter and mean blood flow volume of ascending aorta and thoracic descending aorta(P<0.05), There were no significance between mean flow velocity of the ascending aorta and thoracic descending aorta between sexes (P> 0.05). (2) There were significant difference between ages in values of diameter, mean blood flow volume and mean flow velocity of ascending aorta and thoracic descending aorta(P<0.05). With age rising, diameters of aorta enlarge gradually, the average blood flow and mean flow velocity of aorta decreased gradually. (3) females were larger than Males in the rate of diameter changes of aortic (ascending aorta 4.73%,2.01%; thoracic descending aorta 0.58%,0.51%). With age rising, the rates of diameter changes of aortic decreased gradually (ascending aorta 5.20%、3.82%、2.31%; thoracic descending aorta 0.81%、0.53%,0.03%).Conclusion:(1) PC MRI is a safe, non-invasive, rapid, accurate, informative, high repeatability method in measurement of parameters of aortic blood flow. The accuracy and repeatability of PC MRI is better than UCG, this method can be seen as the "gold standard" measurement of thoracic aortic blood flow. (2) There have difference in diameter, mean blood flow volume of ascending aorta and descending aorta between sexes and ages. There have no difference in mean flow velocity of ascending aorta and descending aorta between sexes. There have difference in mean flow velocity of ascending aorta and descending aorta between ages. (3) The reference range of different ages, different genders in ascending aortic:mean blood flow and mean flow velocity of 20-39 year old male is 5.56-7.13L/min, 9.45～27.63cm/s; Mean blood flow and mean flow velocity of 20～39 year old female is 4.98～6.27L/min,8.48～24.30cm/s. Mean blood flow and mean flow velocity of 40～59 year old male is 5.42～6.17L/min,9.21～23.91cm/s; Mean blood flow and mean flow velocity of 40～59 year old female is 4.82～5.37L/min,8.19～20.81 cm/s. Mean blood flow and mean flow velocity of 60～80 year old male is 5.59～6.16L/min,9.50-23.87cm/s; Mean blood flow and mean flow velocity of 60～80 year old female is 4.68～5.15L/min,7.96～19.96cm/s. (4) the reference range of different ages, different genders in descending aorta:mean blood flow and mean flow velocity of 20～39 year old male is 4.72～6.06L/min,8.02～23.4cm/s; Mean blood flow and mean flow velocity of 20～39 year old female is 4.23～5.32L/min,7.19～20.62cm/s. Mean blood flow and mean flow velocity of 40～59 year old male is 4.60～5.24 L/min,7.82～20.31 cm/s; Mean blood flow and mean flow velocity of 40～59 year old female is 4.09～4.56 L/min,6.95～17.67cm/s. Mean blood flow and mean flow velocity of 60～80 year old male is 4.75～5.23L/min,8.07～20.27cm/s; Mean blood flow and mean flow velocity of 60～80 year old female is 3.97～4.37L/min,6.75～16.93cm/s.更多还原