基于冠状动脉血管分支流量分配方法的血流储备分数数值模拟研究

目的在个性化无创计算血流储备分数(fractional flow reverse,FFR CT )中,流量边界条件的分配准确性往往是一个问题。本文基于种内标度律,提出了一种体积-流量关系的冠脉血流量分配方法进行血流量分配。方法对16例患者冠状动脉血管造影(CT angiography,CTA)图像进行重建,测量出各分支的体积,再经过标度律的方法将冠脉总流量以体积分配比分配到各分支出口。以临床FFR值和最终计算的血流动力学模拟值作分类对比,比较以往的管径流量模型分配方法和体积流量分配方法的准确性。结果基于体积法计算的FFR CT 误差为10.47%,基于管径法计算的FFR CT 为11.76%,并且体积分配方法与管径分配方法具有较好的一致性(80%)。结论本文结果可为临床无创检测FFR提出新的计算方法,并推动FFR CT 的临床应用研究。     

冠状动脉病变特征对心肌缺血的影响

目的 探究狭窄血管的弹性和斑块性质等病变特征对心肌缺血的影响。方法 建立基于流固耦合的几何多尺度冠脉狭窄理想模型,仿真计算血流储备分数（fractional flow reserve, FFR）,评估心肌缺血状况。单独考虑血管弹性壁（弹性模量为1 MPa）和刚性壁、斑块类型（富脂、钙化）以及斑块体积对心肌缺血的影响。结果 在所有狭窄率下,弹性壁血管FFRCT计算结果均大于刚性壁。富脂斑块病变的FFRCT高于钙化斑块的FFRCT（P=0.001）。梯形的斑块体积大于余弦形斑块体积,并且其FFRCT小于余弦形斑块（P=0.001）。结论 血管弹性是模拟血管血流动力学的必要因素。在中等狭窄程度下,由于富脂斑块有更大的管腔变形扩张,钙化斑块更容易引发心肌缺血。在狭窄率一定时,斑块体积越大,FFRCT越小,心肌缺血的可能性越大。     

FFR值与冠动脉狭窄度的数值模拟

目的：利用有限体积法对冠状动脉进行数值模拟,探讨不同狭窄程度的冠状动脉简化模型在舒张期血液的压力分布,并以此计算出（Fractional Flow Reserve,FFR）FFR值,阐明冠状动脉不同狭窄程度与肿值之间的关系,为冠状动脉狭窄的诊断提供参考。方法：以血流动力学基本原理建立不同狭窄度冠脉的物理模型,利用有限体积法,计算不同狭窄几何模型的速度、压力和壁面剪切力等血液流体动力学特征。利用开源软件OpenFOAM对人的冠状动脉不同狭窄程度的简化模型进行血流三维数值模拟。结果：计算获得了人的左冠状动脉不同狭窄程度的血流在舒张期压力分布图。当狭窄程度小于70％,FFR值下降缓慢;当狭窄程度在70％和90％之间内,彤R值下降速度明显加快,当狭窄程度大于90％时,FFR值急速下降,另外,当狭窄程度在大于80％之后,冠脉血管内血流流场的速度压力变化加大。结论：通过对不同狭窄度下冠脉血管血液流体动力学特性的计算,进一步说明有限体积法对冠脉狭窄的模拟问题的计算,人左冠状血管狭窄的百分数与冠脉的FFR值并不是呈线性关系,而是呈曲线样改变。     

血管壁弹性模量对颈动脉狭窄血流储备分数的影响

目的探索将血流储备分数(fractional flow reserve,FFR)引入颈动脉狭窄评估的可行性,并且分析血管壁弹性模量对颈动脉狭窄中血液动力学参数和FFR计算结果的影响。方法利用计算机辅助设计软件建立颈动脉分叉标准模型并获得不同狭窄率的模型。假设血管壁为线弹性材料,血液为不可压缩牛顿流体,在脉动流条件下,利用有限元分析软件进行颈动脉狭窄模型中血液流动的流固耦数值模拟,获得各种血液动力学参数,并计算相应的FFR值。结果当弹性模量固定时,随着狭窄率增加,模型中狭窄部位的FFR逐渐减小,且此时其弹性壁与刚性壁的FFR相对差异随着狭窄率的增加而增加;当狭窄率固定为70%时,随着弹性模量增加,FFR会逐渐减小。结论采用FFR对颈动脉狭窄程度进行功能性评估需要考虑血管壁弹性的影响;狭窄率越大,血管壁弹性模量对FFR的影响越大。     

磁共振成像在颈动脉狭窄中的诊断价值

目的探讨磁共振成像在颈动脉狭窄诊断中的价值。方法对30例患者行磁共振检查（MRA和MRI）,其中23例行数字减影血管造影（DSA）,以颈总动脉法（CC法）计算狭窄率。结果以DSA检查结果为金标准,磁共振诊断颈动脉狭窄及闭塞的敏感性、特异性、假阴性率及假阳性率分别为97.06%、70.59%、2.94%、29.41%。结论MRA结合MRI可作为诊断颈动脉狭窄的筛选检查。     

胸膜凹陷征量化分析在外周孤立性肺结节CT定性诊断中的应用价值

目的：通过量化分析的方法,探讨胸膜凹陷相关切迹( NNPI)在孤立性肺结节( SPN) CT定性诊断中的应用价值。方法回顾性分析2009年1月—2013年12月在复旦大学附属华东医院诊治的90例CT发现有NNPI的SPN患者的病例资料,其中男42例,女48例；年龄31~76岁,平均58岁。 SPN均经手术或穿刺活检病理证实。应用GE 4.4工作站后处理软件测算SPN及NNPI相关参数：SPN体积( V)、NNPI牵拉程度最大的横断面积( Smax)以及结节所在 Smax的横断面中心与NNPI顶点连线的距离( d)。应用Pearson相关分析分析三者之间的相关性,计算结节的牵拉系数K=( Smax × d)/V。分别计算出良恶性结节的K值,应用两独立样本秩和检验判断其统计学差异。作出K值的ROC曲线,计算其在判断良恶性结节中的最佳敏感性、特异性、阳性预测值、阴性预测值及准确率,并与两名有经验的影像科医师采用盲法阅片所得出的敏感性、特异性、阳性预测值、阴性预测值及准确率进行纵向比较。结果通过Pearson相关分析证实Smax、V及d三者具有相关性,Smax与V具有中等程度正相关性(r=0.65,P<0.05),与d存在高度负相关(r=-0.83,P<0.05)。腺癌的K值高于炎性肉芽肿、结核、真菌性肉芽肿、错构瘤等良性 SPN 的 K 值,差异均有统计学意义( Z =-3.57、-4.09、-3.19、-2.97,P值均<0.01)；而炎性肉芽肿、结核、真菌性肉芽肿、错构瘤之间的K值差异均无统计学意义(P值均>0.05)。 ROC曲线分析得出K值的cut-off值为0.052,曲线下面积为0.852,通过K值法判断结节的良恶性所得出的最佳敏感性、特异性、阳性预测值、阴性预测值及准确率分别为78.0%、92.5%、92.8%、77.1%、84.4%,而医师直观阅片所得出的敏感性、特异性、阳性预测值、阴性预测值及准确率分别为64.0%、82.5%、82.1%、64.7%、72.2%,K值法得出的各项数据均高于医师形态学判断方法。结论 K值法对于SPN良恶性的鉴别有临床应用价值,准确性高于医生形态学判断方法。     

心肌血流储备分数在冠状动脉临界病变中的应用

目的:探讨心肌血流储备分数(FFR)在冠状动脉临界病变处理中的意义。方法:经冠状动脉造影(CAG)证实单支血管病变程度介于50%～70%的临界病变心脏病患者24例,对狭窄血管行FFR测定,测量值FFR<0.75的患者行支架植入,FFR≥0.75的患者行药物治疗,8个月后比较两组患者的冠状动脉狭窄程度、FFR及心绞痛发生情况。结果:FFR<0.75组植入支架前后冠脉狭窄程度由(68.00±10.00)%下降到(8.00±2.00)%(P<0.01),FFR值由(0.70±0.03)%提高到(0.92±0.03)%(P<0.01),心绞痛发生例数由10例减少为0例(P<0.01)。FFR≥0.75组药物治疗前后各指标比较无明显差异(P>0.05)。组间治疗后比较,FFR<0.75组冠脉狭窄程度较FFR≥0.75组显著降低,FFR值升高,心绞痛发生例数减少为0(P均<0.01)。结论:在冠状动脉临界病变中测量FFR值能有效评估心肌供血情况,为临床是否行支架植入提供参考。     

板层小体计数预测新生儿呼吸窘迫综合征临床观察

目的通过肺成熟度预测对可能发生新生儿呼吸窘迫综合征的早产儿进行积极预防,同时避免部分早产儿不必要的气管插管及PS使用。方法对136例正常新生儿及早产儿进行板层小体计数,尝试找出反应肺成熟度的不成熟判定界值和成熟判定界值,并统计其对肺成熟度的阳性预测值、阴性预测值、敏感性、特异性,以避免部分早产儿不必要的气管插管及PS的使用。结果成熟判定界值≥98000/uL时其阴性预测值100%;阳性预测值17.4%;敏感性100%;特异性36.7%;不成熟判定界值≤33000/uL时阴性预测值98%;阳性预测值36.8%;敏感性87.5%;特异性81.7%。     

p16ink4a与Ki-67用于人宫颈病变 辅助诊断的比较

目的对p16ink4a与Ki-67作为辅助诊断人宫颈病变的两种标记物进行比较。方法采用免疫组织化学方法,检测p16ink4a与Ki-67蛋白在42例人正常宫颈组织,21例人宫颈上皮内瘤样变(CIN)Ⅰ级、21例CINⅡ、36例CINⅢ组织中的表达,用等级相关方法分析p16ink4a、Ki-67表达水平与CIN等级之间的相关性。计算两种标记物的敏感性、特异性、阳性预测价值、阴性预测价值和约登指数。结果p16ink4a和Ki-67表达均与CIN等级呈正相关。p16ink4a检测人宫颈病变的敏感性为83.3%,特异性为90.5%,阳性预测值为94.2%,阴性预测值为74.5%,约登指数为0.738。Ki-67检测人宫颈病变的敏感性为98.7%,特异性为16.7%,阳性预测值为68.75%,阴性预测值为87.5%,约登指数为0.154。联合使用两种标记物的敏感性、特异性均为83.3%。结论Ki-67敏感性、阴性预测值高,但特异性差,适用于早期发现人宫颈病变。p16ink4a特异性、阳性预测值高,是辅助诊断人宫颈病变的较好指标。综合比较,p16ink4a优于Ki-67。     

基于数据驱动的冠状动脉微循环阻力快速计算方法

目的 开发一种基于数据驱动的冠状动脉微循环阻力快速计算方法。 方法 构建和优化神经网络对冠状动 脉进行截面积特征提取,利用截面积特征、异速标度律和流量分配比例快速计算冠状动脉分支末端的微循环阻力, 并基于微循环阻力无创计算血流储备分数。 结果 为了验证神经网络的有效性,将 40 个临床收集的冠状动脉分 支测量的截面积特征与神经网络预测的结果进行比较,平均绝对误差为 1. 08 mm2 。 为了验证微循环阻力值的准确 性,将 15 位患者的临床血流储备分数与利用微循环阻力值计算的血流储备分数进行比较,计算准确性为 86. 6% 。 结论 本文提出的冠状动脉微循环阻力快速计算方法具有潜在的临床应用价值。     

Determination of fractional flow reserve (FFR) based on scaling laws: a simulation study

Fractional flow reserve (FFR) provides an objective physiological evaluation of stenosis severity. A technique that can measure FFR using only angiographic images would be a valuable tool in the cardiac catheterization laboratory. To perform this, the diseased blood flow can be measured with a first pass distribution analysis and the theoretical normal blood flow can be estimated from the total coronary arterial volume based on scaling laws. A computer simulation of the coronary arterial network was used to gain a better understanding of how hemodynamic conditions and coronary artery disease can affect blood flow, arterial volume and FFR estimation. Changes in coronary arterial flow and volume due to coronary stenosis, aortic pressure and venous pressure were examined to evaluate the potential use of flow and volume for FFR determination. This study showed that FFR can be estimated using arterial volume and a scaling coefficient corrected for aortic pressure. However, variations in venous pressure were found to introduce some error in FFR estimation. A relative form of FFR was introduced and was found to cancel out the influence of pressure on coronary flow, arterial volume and FFR estimation. The use of coronary flow and arterial volume for FFR determination appears promising.     

冠脉CT与冠脉造影诊断心肌桥的临床价值比较

目的:比较冠脉CT与冠脉造影诊断心肌桥的临床价值。方法:收集2015年7月~2020年7月苏州大学第二附属医院心内科收治的107例疑似冠心病患者临床资料。依次进行冠脉CT和冠脉造影检查,计算壁冠状动脉（MCA）狭窄程度,观察前降支、对角支、钝缘支、后降支和回旋支冠脉分布走行以及与心肌的关系,测量心肌桥长度和厚度。比较两种检查方法图像质量优良率、心肌桥检出率以及心肌桥测量指标。分析两种检查方法显示MCA狭窄程度和诊断心肌桥的一致性。以冠脉造影为金标准,计算敏感度、特异度、准确度、阳性预测值、阴性预测值,评估冠脉CT判断MCA中重度狭窄和诊断心肌桥的价值。结果:两种检查方法图像质量优良率均较好,冠脉CT心肌桥检出率显著高于冠脉造影（25.23% vs 14.02%, P<0.05）;冠脉CT测得心肌桥长度大于冠脉造影,MCA狭窄程度低于冠脉造影,差异具有统计学意义（P<0.05）;冠脉CT和冠脉造影显示MCA狭窄程度的一致性较好（Kappa=0.832, P<0.05）;与冠脉造影比较,冠脉CT判断MCA中重度狭窄的敏感度、特异度、准确度、阳性预测值、阴性预测值分别为90.63%、86.67%、74.36%、95.59%、87.85%;冠脉CT和冠脉造影诊断心肌桥的一致性较好（Kappa=0.815, P<0.05）;与冠脉造影比较,冠脉CT诊断心肌桥的敏感度、特异度、准确度、阳性预测值、阴性预测值分别为64.29%、73.33%、69.23%、68.75%、68.97%。结论:冠脉CT与冠脉造影对心肌桥诊断均具有一定价值,而冠脉CT具有无创性、图像质量优良率高,且对心肌桥位置及分布显示佳,并对MCA狭窄具有较高敏感度和特异度,更具临床应用优势。     

The utility of multi-detector row spiral CT for detection of coronary artery stenoses

Contrast-enhanced multi-detector row spiral computed tomography (MDCT) was introduced as a promising noninvasive method for vascular imaging. This study examined the accuracy of this technique for detecting significant coronary artery stenoses. Both MDCT(Sensation 16, Siemens, Germany, 12x0.75 mm collimation and 0.42 sec rotation speed, 120 kV, 500 effective mA, and 2.7 mm/rotation table-feed) and invasive coronary angiography (CAG) were performed on 61 patients (mean age 59.2+/-10, 44 men) who were suspected of having coronary artery disease. All patients were treated with atenolol (25-50 mg) prior to imaging and the heart rate was maintained below 65 beats per minutes during image acquisition. The images were reconstructed in the diastole around TI-400 ms with a 0.5 mm increment and a 1.0 mm thickness. All coronary arteries with a diameter of 2.0 mm or more were assessed for the presence of a stenosis (>50% luminal narrowing). Two independent radiologists who were unaware of the results of the invasive CAG evaluated the MDCT data, and the results were compared with those from the invasive CAG (interval 1-27, mean 11 days). An evaluation of the CT coronary angiogram (CTCA) was possible in 58 of the 61 patients (95%). Image acquisition of the major coronary arteries including the left main trunk was available in 229 out of 244 arteries. Invasive CAG showed that 35 out of 58 patients had significant coronary artery stenoses by. patient analysis of those who could be evaluated showed that CT coronary angiography correctly classified 30 out of 35 patients as having at least 1 coronary stenosis (sensitivity 85.7%, specificity 91.3%, positive predictive value 93.8%, negative predictive value 80.8%). By analyzing each coronary artery, CAG found 62 stenotic coronary arteries in the 229 coronary arteries that could be evaluated. MDCT correctly detected 50 out of 62 stenotic coronary arteries and an absence of stenosis was correctly identified in 156 out of 167 normal coronary arteries (sensitivity 80.6%, specificity 93.4%, positive predictive value 81.9%, negative predictive value 92.8%). The non-invasive technique of MDCT for examining the coronary artery appears to be a useful method for detecting coronary artery stenoses with a high accuracy particularly with the proximal portion and large arteries.     

Hyperemic versus non-hyperemic indexes for coronary physiology assessment in patients with severe aortic stenosis

PurposeRecent data suggests that fractional flow reserve (FFR) may underestimate intermediate coronary stenosis in the presence of severe aortic stenosis (AS), whereas instantaneous wave-free ratio (iFR) values may remain similar after treatment of AS, yet the evidence still lacks to use iFR as the reference. We aimed to compare FFR/iFR values in the AS setting.Materials and methodsThe functional significance of 416 coronary lesions in 221 patients with severe AS was investigated with iFR and FFR.ResultsThe diagnostic agreement between iFR and FFR has been tested, using the cut-off value of 0.89 for iFR and 0.80 for FFR. The mean diameter stenosis was 58.6 ​± ​13.4% with FFR of 0.85 ​± ​0.07 and iFR of 0.90 ​± ​0.04. FFR ≤0.80 was identified in 26.0% and iFR≤0.89 in 33.2% of interrogated vessels. Good agreement between iFR and FFR was confirmed (Intraclass Correlation Coefficient 0.83 [95%CI 0.79-0.85]). The overall diagnostic accuracy (AUC in ROC analysis) of FFR in detecting iFR≤0.89 was 0.997 (95%CI 0.986 to 1.000; p<0.001) and of iFR in detecting FFR≤0.80 was 0.995 (95%CI 0.983 to 0.999; p<0.001). The optimal cut-off value for FFR to detect iFR≤0.89 was 0.82 with sensitivity, specificity, and accuracy of 97.1%, 98.9%, and 97.7%, respectively, and for IFR to detect FFR≤0.80 was 0.88 with sensitivity, specificity, and accuracy of 99.1%, 95.8%, and 97.4%, respectively.ConclusionIn the presence of AS, FFR has good agreement with iFR. However, the optimal FFR/iFR threshold to identify iFR≤0.89/FFR≤0.80 may be different from the standard thresholds of ischemia.     

基于深度神经网络的冠脉造影图像的血管狭窄自动定位及分类预测

提出一套基于深度神经网络与监督学习的算法,用于对冠状动脉图像中的血管狭窄特征进行自动检测和分类。主要利用冠脉造影定量分析(QCA)作为标签进行监督学习,将冠脉狭窄的严重程度分为正常(<25%狭窄分数)、狭窄(>25%狭窄)类别,并实现图像中的狭窄定位检测。利用inception模型作为基础分类器,对图像级狭窄进行初步分类;随后结合多层次池化结构,对多视角造影图像进行联合预测,以获取左动脉/右动脉/患者级狭窄预测。在分类器的基础上进一步提取特征,分别利用监督学习/非监督学习模型,实现图像中的狭窄定位。在235例临床研究共计13 744张图像上,用所述方法进行训练及交叉验证。结果表明,在图像级狭窄分类上,该算法可以达到85%的准确率和0.91的AUC分数;在多视图联合预测实验中,针对左/右/患者级的狭窄进行分类预测,分别达到0.94/0.90/0.96的灵敏度与0.87/0.88/0.86的AUC分数。在狭窄定位实验中,针对左/右动脉狭窄检测的灵敏度分别为0.70/0.68;在512像素×512像素的图像中,均方误差分别为37.6/39.3像素。实验证明,该算法可实现从图像到病人的辅助诊断预测潜力,具有较高的精确度;不仅能提供冠脉造影过程中的初步筛选能力,而且为更精确和自动化的计算机辅助诊断奠定基础。     

Computerized two-lead resting ECG analysis for the detection of coronary artery stenosis

BACKGROUND: Resting electrocardiogram (ECG) shows limited sensitivity and specificity for the detection of coronary artery disease (CAD). Several methods exist to enhance sensitivity and specificity of resting ECG for diagnosis of CAD, but such methods are not better than a specialist's judgement. We compared a new computer-enhanced, resting ECG analysis device, 3DMP, to coronary angiography to evaluate the device's accuracy in detecting hemodynamically relevant CAD. METHODS: A convenience sample of 423 patients without prior coronary revascularization was evaluated with 3DMP before coronary angiography. 3DMP's sensitivity and specificity in detecting hemodynamically relevant coronary stenosis as diagnosed with coronary angiography were calculated as well as odds ratios for the 3DMP severity score and coronary artery disease risk factors. RESULTS: 3DMP identified 179 of 201 patients with hemodynamically relevant stenosis (sensitivity 89.1%, specificity 81.1%). The positive and negative predictive values for identification of coronary stenosis as diagnosed in coronary angiograms were 79% and 90% respectively. CAD risk factors in a logistic regression model had markedly lower predictive power for the presence of coronary stenosis in patients than did 3DMP severity score (odds ratio 3.35 [2.24-5.01] vs. 34.87 [20.00-60.79]). Logistic regression combining severity score with risk factors did not add significantly to the prediction quality (odds ratio 36.73 [20.92-64.51]). CONCLUSIONS: 3DMP's computer-based, mathematically derived analysis of resting two-lead ECG data provides detection of hemodynamically relevant CAD with high sensitivity and specificity that appears to be at least as good as those reported for other resting and/or stress ECG methods currently used in clinical practice.     

冠心病患者心电图ST段改变与多排螺旋CT冠状动脉成像的关系分析

目的:通过对心电图ST段改变及多排螺旋CT冠状动脉成像（MSCTCA）检查在冠心病诊断中的比较分析，探讨冠心病诊断中心电图和MSCTCA检查的方法和作用，为临床诊断提供更多有效的信息。方法:选取临床诊断疑似或确诊为冠心病患者64例，进行心电图和MSCTCA检查，比较两种方法的一致性，不同部位、不同程度及不同类型病变检查的阳性率。结果:与MSCTCA方法相比，心电图ST段改变检查的灵敏度为56.82%，特异度为50%，总体符合率为54.69%，Kappa值为0.061，两种方法检查一致性较差，差异具有显著性（P<0.05）；I/avL/V1-5导联ST段改变阳性患者与Ⅱ/Ⅲ/avF导联ST段改变阳性患者相比，以MSCTCA检查的阳性率更高（P<0.05）；冠状动脉重度狭窄患者与轻度患者相比，心电图ST段改变阳性率显著升高（P<0.05）；中度狭窄患者与轻度患者相比，心电图ST段改变阳性率差异不显著（P>0.05）；多支冠状动脉病变患者心电图ST段改变阳性率显著高于单支管状动脉病变患者（P<0.05）。结论:心电图与MSCTCA检查一致性较差，临床上不宜单独使用单一检查方法；在重度冠状动脉狭窄患者及多支冠状动脉病变患者中，心电图ST段改变检出率较高，结果具有参考价值；I/avL/V1-5导联ST段改变阳性患者相比Ⅱ/Ⅲ/avF导联ST段改变阳性患者，MSCTCA检查阳性率更高，更具有检测意义。