区分T1-2与T3-4期胃癌CT影像组学模型的建立与验证

目的:探讨基于CT影像组学构建的模型术前鉴别T1-2与T3-4期胃癌的价值。方法:回顾性分析465例术前行腹部CT增强扫描且经切除术后T分期明确的胃癌患者,将其分为T1-2期及T3-4期两组,采用分层抽样方法按7∶3分为训练集及测试集。在其静脉期CT图像上进行感兴趣区(ROI)的勾画及影像组学特征的提取。采用LASSO回归筛选出与T分期相关性最高的特征,分别利用逻辑回归、支持向量机及决策树建立影像组学模型。基于影像组学特征建立影像组学标签,基于临床特征建立临床模型,结合影像组学标签及临床特征构建影像组学诺模图。使用受试者工作特征(ROC)曲线评价各模型鉴别T分期的效能;Delong检验比较最优影像组学模型与临床模型的ROC曲线下面积(AUC)的差异性及诺模图与二者中效能更好的模型之间AUC的差异性;采用校准曲线评价模型评估与实际病理结果的匹配性,决策曲线评价模型的临床净收益。结果:影像组学模型中,逻辑回归模型的预测效能最好,在训练集和测试集上的AUC分别为0.864、0.836,均高于临床模型;结合影像组学标签及临床特征生成的影像组学诺模图预测效能优于3种影像组学模型和临床模型,在训练...     

CT影像组学联合临床特征在预测肺腺癌EGFR突变中的价值

目的探究CT影像组学联合临床特征对肺腺癌EGFR突变状态的预测效能。方法对125例肺腺癌病人进行回顾性研究,分成训练组（n=74）与验证组（n=51）,基于CT成像提取影像组学特征;采用支持向量机（SVM）分类器,分别构建临床模型、影像组学模型以及联合模型;受试者工作特征曲线（ROC）及曲线下面积（AUC）用于评价模型的预测效能。结果临床模型、影像组学模型以及联合模型在训练组中的AUC分别为0.749（0.653~0.843）、0.818（0.711~0.898）、0.860（0.760~0.930）,在验证组中的AUC分别为0.753（0.612~0.863）、0.797（0.661~0.896）、0.855（0.728~0.938）。结论对于肺腺癌EGFR突变状态的预测,CT影像组学特征优于临床因素与CT征象,当影像组学结合临床因素与CT征象,能进一步提高预测效能。     

CT影像特征及影像组学在肺部淋巴瘤与肺浸润性黏液腺癌诊断中的应用

目的 探讨CT影像特征及影像组学鉴别诊断肺部淋巴瘤与肺浸润性黏液腺癌(PIMA)的价值。方法回顾性纳入2016年1月-2022年1月湖北省中西医结合医院收治的37例肺淋巴瘤(淋巴瘤组)和68例PIMA(PIMA组)患者,按7:3随机分为训练组73例(淋巴瘤27例,PIMA46例)和验证组32例(淋巴瘤12例,PIMA20例),分析各组临床、影像学资料,并提取影像组学特征,利用LASSO十折交叉验证进行特征选择,建立联合模型,绘制受试者工作特征(ROC)曲线检验CT影像特征及影像组学特征模型对肺淋巴瘤和PIMA的鉴别效能。结果 训练组中淋巴瘤组的空气支气管征、支气管扩张及胸腔积液检出率均高于PIMA组,差异有统计学意义(P<0.05);验证组中淋巴瘤的空气支气管征、支气管扩张检出率高于PIMA组,差异有统计学意义(P<0.05);保留空气支气管征、支气管扩张及胸腔积液建立CT影像特征模型,训练组ROC曲线下面积(AUC)=0.886,验证组AUC=0.792;保留5个最佳特征子集构建CT影像组学特征模型,训练组AUC=0.889,验证组AUC=0.842;联合模型训练组AUC...     

CT影像组学模型在小细胞肺癌与非小细胞肺癌鉴别的价值

目的 探讨肺癌CT影像组学特征用于鉴别小细胞肺癌(small cell lung cancer,SCLC)和非小细胞肺癌(non-small cell lung cancer,NSCLC)的价值.方法 回顾性分析经2010-01/2020-12年来自首都医科大学电力教学医院和首都医科大学大兴教学医院的89例肺癌患者的临床和影像资料的病理证实,其中SCLC 24例,NSCLC 65例.采用Python语言PyRadiomics软件包提取影像组学特征,使用最大相关-最小冗余(max-relevance and minredundancy,mRMR)算法和最小绝对收缩和选择算法(least absolute shrinkage and selection operator,LASSO)回归分析筛选影像组学特征.利用多变量Logistic回归构建预测模型,应用受试者工作特征曲线(receiver operating characteristic curve,ROC)评价预测模型的诊断效能,联合影像组学标签与临床特征构建列线图.结果 从所提取的788种影像组学特征中,最终筛选了其中8种重要特征用于构建影像组学模型.训练组、测试组影像组学模型鉴别SCLC与NSCLC的ROC曲线下面积(area under the curve,AUC)分别为0.93(95％CI:0.85～1.00)、0.92(95％CI:0.80～1.00).联合诊断模型在测试组的诊断效能(AUC=0.93,95％CI:0.84～1.00)高于临床预测模型(AUC=0.73,95％CI:0.52～0.93)和影像组学模型(AUC=0.92,95％CI:0.80～1.00).结论 基于CT平扫的影像组学模型鉴别SCLC与NSCLC有较高的诊断效能,结合患者临床资料的联合模型较影像组学模型有更高的诊断效能.     

CT影像特征及影像组学在肺淋巴瘤与肺浸润性黏液腺癌诊断中的应用

目的:探讨CT影像特征及影像组学鉴别诊断肺黏膜相关淋巴组织型淋巴瘤(MALT)与肺浸润性黏液腺癌(PIMA)的应用价值。方法:50例经病理证实肺MALT患者及52例PIMA患者,按照2∶1随机分为训练集68例(33例MALT,35例PIMA)和验证集34例(17例MALT,17例PIMA)。比较训练集和验证集CT征象并提取验证集肺MALT和PIMA的影像组学特征参数,采用LASSO降维和Logistic回归,经过交叉验证后建立预测模型。结果:验证集共获得6个影像组学特征,包括4个一阶特征、2个纹理特征;ROC曲线分析显示,训练集和验证集鉴别诊断肺MALT、PIMA的AUC分别为0.873、0.852,模型拟合优度良好。结论:基于CT影像特征及影像组学构建的预测模型预测效能良好,可以鉴别诊断肺MALT和PIMA。     

基于临床及影像组学构建中轴性脊柱关节病支持向量机预测模型

目的：基于临床及影像组学采用支持向量机（SVM）构建中轴性脊柱关节病（ax Sp A）的预测模型。方法：回顾性收集2012年10月至2019年2月在温州医科大学附属第一医院就诊的568例腰背痛患者,最终诊断axSpA 319例,非axSpA 249例。按7:3将患者随机分为训练组与验证组。于骶髂关节CT上手动勾画三维感兴趣区（VOI）并提取影像组学特征,应用最小冗余最大相关性（mRMR）及最小绝对收缩和选择算子（LASSO）算法进行降维及选择最优影像组学特征;采用单因素和多因素Logistic回归分析寻找诊断axSpA的临床危险因素。最后使用SVM分别构建临床、影像组学及临床-影像组学联合模型,利用受试者工作特征（ROC）曲线及Delong检验评估模型的诊断效能。结果：临床-影像组学联合模型在验证组中具有最佳诊断效能,诊断准确性为0.83,灵敏度和特异度分别为85.2%、79.7%,其ROC曲线下面积（AUC=0.91）高于临床模型（AUC=0.81）及影像组学模型（AUC=0.83）,差异均有统计学意义（P<0.05）。结论：基于临床和影像组学构建SVM模型对诊断axSpA具有...     

CT影像组学在预测非小细胞肺癌淋巴结转移中的价值

目的探讨基于胸部CT影像组学在术前预测非小细胞肺癌淋巴结转移中的价值。方法回顾性分析经术后病理证实的143例非小细胞肺癌病人临床、胸部CT增强影像资料。按照7:3比例,随机分为训练组（n=100）和验证组（n=43）。在静脉期图像上提取肿瘤的影像组学特征,采用最小绝对收缩选择算子（LASSO）逻辑回归用于数据降维、特征筛选。分别基于影像组学特征和临床-影像特征（最大径、毛刺征）构建预测模型。采用受试者工作特征曲线（ROC）的曲线下面积（AUC）评价不同模型的鉴别预测效能,并对模型的ROC曲线行Delong检验;在验证组中评估其预测效能。结果共提取939个影像组学特征,经筛选最终得到6个最优特征并建立影像组学预测模型。对于术前预测淋巴结转移的效能,在训练组中,影像组学模型AUC为0.864（95%CI:0.781~0.924）,大于临床模型的AUC为0.662（95%CI:0.561~0.754）（P < 0.01）;在验证组中,影像组学模型AUC为0.860（95%CI:0.720~0.964）,大于临床模型的AUC为0.664（95%CI:0.504~0.880）（P < 0.05）。结论基于胸部CT增强图像提取影像组学特征及其构建的预测模型,影像组学模型的效能高于临床模型,可以作为一种预测非小细胞癌病人淋巴结是否转移的辅助工具,具有良好的临床应用前景。     

不同类型小波滤波对影像组学特征相关性和诊断效能的影响

目的：探讨不同小波滤波对影像组学特征相关性和诊断效能的影响。方法：回顾性收集143例结直肠癌患者(淋巴结转移阳性64例,阴性79例)的术前CT图像,经放射科医师勾画肿瘤区域后,使用Matlab编写的软件提取不同类型小波的影像组学特征。通过计算相关系数分析不同小波间同名特征的相关性。采用最小绝对收缩和选择算子(the least absolute shrinkage and selection operator,LASSO)构建不同的小波特征集预测淋巴结转移的影像组学标签并采用Delong’s检验比较其效能。结果：随着小波阶数差异的增大,小波间高相关同名特征数量减少。部分特征在不同小波间易出现高相关性。单个小波的特征集中rbio2.2,sym7和db7的特征子集构建的影像组学标签诊断效能最高。Daubechies系列小波特征集构建的标签预测淋巴结转移效能最高,Biorthogonal系列小波标签则最低,在去除同名高相关特征后全体特征集的诊断效能显著提高(P=0.004)。结论：建议选择阶数差异大的小波以降低影像组学特征的数据冗余度。为提高标签的诊断效能,有必要去除高相关特征。     

多模态颅脑MRI影像组学特征在预测胶质母细胞瘤患者生存风险分层中的应用研究

目的探讨多模态颅脑MRI影像组学特征在预测胶质母细胞瘤（GBM）患者生存期风险分层中的作用。方法回顾性分析BRATS2018数据库中经手术病理证实的GBM患者163例,按入组时间分为训练组114例,测试组49例。提取所有患者术前MRI图像影像组学特征,评估传统影像视觉特征,然后对训练组数据使用最大相关-最小冗余算法和梯度提升决策树算法进行降维后建立影像组学标签模型,计算患者的影像组学标签分数,最终结合影像视觉特征和临床因素,使用多元逻辑斯回归构建总生存期联合预测模型并绘制列线图。基于测试组数据使用ROC曲线评估模型的诊断效能,并用决策曲线分析验证。结果从每例患者的4个MRI序列图像、5个感兴趣区共提取纹理特征7920个,经降维后筛选出26个最优价值特征构建影像组学标签。使用多元逻辑斯回归构建包含了深部白质、年龄和影像组学标签的联合诊断模型,并生成列线图,该模型在训练组和测试组中预测长短生存期的准确率分别为0.848和0.800。列线图、联合影像、影像组学标签、深部白质受累和年龄在所有患者中的诊断准确率分别为0.941、0.908、0.873、0.663和0.655。基于模型区分的高危组与低危组中的GBM患者数差异有统计学意义（P＜0.05）。结论影像组学标签、深部白质和年龄是GBM患者的独立预测因子,基于三者的联合模型而绘制的列线图可用于预测GBM患者总生存期,有助于进行生存风险分层。     

基于CT影像组学构建模型对实性肺结节鉴别的价值

  目的  探讨CT影像组学模型对实性肺结节良恶性的诊断效能。  方法  回顾性分析安徽医科大学第二附属医院2019年3月—2022年11月经手术、穿刺或临床证实的231例实性肺结节患者CT影像资料,选择典型的231个肺结节,按病理类型分为良性(98例)和恶性(133例)。采用InferScholar软件分别从二维、三维2个角度对病灶轮廓进行勾画,之后用软件提取影像组学特征,将入组病例以7∶ 3的比例分为训练集和测试集。通过Pearson相关系数、显著性检验、LASSO回归分析方法进行特征筛选。在训练集中分别构建二维、三维影像组学特征模型(模型Ⅰ、模型Ⅱ),用测试集来验证,利用ROC曲线下面积来评价模型的预测效能。  结果  从二维、三维2个角度分别提取出919、1 746个影像组学特征,经过筛选,分别得到12、20个最优影像组学特征,用机器算法构建影像组学模型Ⅰ和模型Ⅱ。训练集中模型Ⅰ的AUC为0.97,模型Ⅱ的AUC为0.98;测试集中模型Ⅰ的AUC、灵敏度、特异度、阳性预测值、阴性预测值和准确率分别为0.94(95% CI:0.87~0.98)、83.9%、89.5%、86.7%、87.2%、87.0%;测试集中模型Ⅱ的AUC、灵敏度、特异度、阳性预测值、阴性预测值和准确率分别为0.97(95% CI:0.94~0.99)、75.9%、97.5%、95.7%、84.8%、88.4%。  结论  基于CT影像组学构建的模型能够较好地预测实性肺结节的良恶性,从三维角度构建的模型Ⅱ的诊断效能优于二维角度构建的模型Ⅰ。      

Value of D-Dimers in patients with acute aortic dissection

Objective: To evaluatel the value of D-dimers in patients with acute aortic dissection (AAD). Methods: This study consisted of 16 patients with AAD and 27 non-AAD patients. Serum D-dimets were measured by Sta-Liatest D-DI immunoturbidimetric assay. Results: D-dimer level was higher (P ＜ 0.001) in patients with AAD(7.91 ± 5.52 μg/ml) than that in non- AAD group(1.57±1.24 μg/ml). D-dimer was positive (＞0.4 μg/ml) in all patients with AAD and in 10 control group patients (37%). Among patients with acute AAD, D-dimers tended to be higher in Stanford A than in Stanford B (8.67 ± 4.31 μg/ml vs. 3.24±1.27 μg/ml, P ＜0.01). D-dimer values tended to be higher in more extended disease(3.84 ± 1.65 μg/ml, 8.57 ± 3.58 μg/ml and 11.87 ± 5.69 μg/ml in thoracic aorta, thoracic and abdominal aorta, thoracic and abdominal aorta and iliacal arteries, respectively, P ＜ 0.05 for both 8.57 ± 3.58 and 11.87 ± 5.69 vs. 3.84 ± 1.65 ). Including the control group into the analysis, we found a sensitivity of 100%, a negative predictive value of 100%, and a specificity of 66% and a positive predictive value of 64% for D-dimer in diagnosis of AAD in our patients with suspected AAD. Conclusion: D-dimer was elevated in patients with AAD. A negative D-dimer test result could be useful in excluding AAD.     

Research of combined liver-kidney transplantation model in rats

Objective： To set up a simple and reliable rat model of combined liver-kidney transplantation. Methods： SD rats served as both donors and recipients. 4℃ sodium lactate Ringer＇s was infused from portal veins to donated livers,and from abdominal aorta to donated kidneys, respectively. Anastomosis of the portal vein and the inferior vena cava （IVC） inferior to the right kidney between the graft and the recipient was performed by a double cuff method, then the superior hepatic vena cava with suture. A patch of donated renal artery was anastomosed to the recipient abdominal aorta. The urethra and bile duct were reconstructed with a simple inside bracket. Results： Among 65 cases of combined liver-kidney transplantation, the success rate in the late 40 cases was 77.5%. The function of the grafted liver and kidney remained normal. Conclusion： This rat model of combined liver-kidney transplantation can be established in common laboratory conditions with high success rate and meet the needs of renal transplantation experiment.     

BLOOD PRESSURE CHANGE WITH AGE IN SALT-SENSITIVE TEENAGERS

Objective To observe blood pressure change with age in salt-sensitive teenagers whose salt sensitivity were determined by repeated testing.Methods Salt sensitivity was determined through intravenous infusion of normal saline combined with volume-depletion by oral diuretic furosemide in 55 teenagers. After five years, salt sensitivity was re-examined and subject blood pressure was followed up. Blood pressure changes in salt-sensitive teenagers were compared to that of non-salt sensitive teenagers over five years.Results After 5 years, the repetition rate of salt sensitivity determined by intravenous saline loading is 92.7%. In teenagers with salt sensitivity on the baseline, both the systolic blood pressure increments and increment rates were much higher than non-salt sensitive teenagers (12.7±12.1 mmHg vs. 2.8±5.2 mmHg, P＜ 0.01; 12.2%± 12.0% vs. 2.5% ±4.4%, P＜ 0.001,respectively). There was a similar trend for diastolic blood pressure (8.4 ± 6.4 mmHg vs. 3.7 ± 6.4 mmHg, P = 0.052; 13.2% ±10.6 % vs. 6.8%± 10.1%, P = 0.053, respectively).Conclusions Salt sensitivity determined by intravenous saline loading showed good reproducibility. Blood pressure increments with age were much higher in salt-sensitive teenagers than non-salt sensitive teenagers, especially in terms of systolic blood pressure.     

安心颗粒对急诊经皮冠状动脉介入术后生活质量影响的研究

目的：评价使用安心颗粒对急诊经皮冠状动脉介入术（PPCI）术后生活质量的影响.方法：将160例接受PPCI的急性ST段抬高型心肌梗死患者随机分为安心颗粒组（术前顿服安心颗粒8.8g,术后安心颗粒4.4 g/次,每日2次）和对照组（仅接受基础药物治疗）.所有患者均服用阿司匹林、氯吡格雷和阿托伐他汀.分别在入院时、出院前1d、出院后180 d时,应用心肌梗死多维度量表（MIDAS）、中文版SF-36评价量表对患者生活质量评分.并观察术后30 d以内的出血并发症、血小板减少症发生情况.结果：入院时和出院前1d,两组患者的心肌梗死MIDAS、SF-36量表评分比较无差异（P＞0.05）;出院后180 d时,与对照组比较,安心颗粒组MIDAS、SF-36评分明显减低（P＜0.05）;组内与入院时比较,两组出院前1d、出院后180 d时,MIDAS、SF-36评分均降低（P＜0.05）.两组患者在随访期间均无大量出血、少量出血、重度和极重度血小板减少症发生,安心颗粒组有4例、对照组有7例发生不明显出血（P＞0.05）.两组发生轻度血小板减少症的患者数比较无差异（P＞0.05）.结论：PPCI使用安心颗粒,能改善急性ST段抬高型心肌梗死患者的生活质量,且不增加出血风险.     

The comparative studies of the influences of Urapidil and Nicardipine on sino-atrial node function, atrio-ventricular node function and hemodynamics

Objective:To investigate the influences of urapidil and nicardipine on rabbit sinus function,atrio-ventricular node function and hemodynamics.Methods:Thirty-two Angora's rabbits were selected and randomly divided into four groups.U1 group:urapidil 0.25 mg/kg;U2 group:urapidil 0.5 mg/kg;N1 group:nicardipine 10 μg/kg;N2 group:nicardipine 20 μg/kg.All these medicine were administrated within 30 seconds.Measurements were taken before and after the administration of urapidil or nicardipine for the following data:mean blood pressure(MAP),heart rate(HR),sino-atrial conduction time(SACT),maximal sinoatrial recovery time(SNRTmax)corrected sinus node recovery time(CSNRT),index of sinus node recovery time(SNRTI),Wenckebach A-V conduction frequency (WB),and P-R interval.Results:Significant MAP and HR changes were identified in all of the four groups before and after administration of both urapidil and nicardipine.No significant changes could be found in the rest of the parameters.Intergroup analysis showed that SACT and CSNRT of N1 and N2 groups were shorter than those of the U2 group(P＜0.01);the MAP decreased(P＜0.01)and the HR increased drastically(P＜0.01).Conclusions:Neither urapidil(0.25 mg/kg,0.5 mg/kg)nor nicardipine(10μg/kg,20μg/kg)has any significant influence on rabbit sinus function or rabbit atrio-ventricular node function.Nicardipine could be a better choice than urapidil for parafunctional sinus node patients.     

Expression of OPGmRNA and ODFmRNA in the patients of hip fracture due to osteoporosis

Objective：To investigate the gene expression of osteoprotegerin（OPG） and osteoclast differentiation factor（ODF） in the bone tissue of patients with hip fracture due to osteoporosis. Methods：OPGmRNA and ODFmRNA in the bone tissue in 50 cases of osteoporosis sufferers（over 50 years old） with hip fracture（Observer Group） and 30 cases of hip facture sufferers with no osteoporosis（Control group） were analyzed with the Semi-Quantitative RT-PCR method. Results：The mRNA expressed of ODF, OPG were both high in the patients with hip fracture. In the control group, the expression of OPG mRNA was observed, while the expression of ODF mRNA was very slight. Conclusion：Aged patients contained all signals including OPG, ODF that are essential for inducing osteoclastogenesis and promoting bone resorption.     

The clinicopathological and immuohistochemical analysis of solid-pseudopapillary tumor of the pancreas： report of 9 cases

Objective：To investigate the clinical features, pathological characteristics and immunophenotype of solid-pseudopapillary tumor of the pancreas（SPTP）. Methods：Nine surgically treated cases of SPTP were retrospectively reviewed. Hematoxylin and Eosin（HE） staining and immunohistochemical staining were used to analyze all cases, and the general clinical data was collected. Results：Six patients were asymptomatic except for a palpable mass. Two patients complained of vague-epigastric pain. One patient appeared jaundice. The tumor was encapsulated and solid tissues alternately with cystic tissues. Histologically, the histological structure of solid portion was pseudopapillary with a fibrovascular core. Tumor cells were uniform and medium-sized which were arranged in sheets ets or nests or pseudopapillary patterns. Immunohistochemical studies demonstrated that SPTP proved positive in vimentin（9/9 cases）, AAT（9/9 cases）, NSE（9/9 cases）, ACT（7/9 cases）, CK20（2/9 cases）, CgA（1/9 cases）, S-100（3/gcases）, PR（4/gcases）, Syn（3/9 cases） and CD56（5/9cases）, negative in CEA and ER. Conclusion：SPTP is a tumor predominantly occurring in young women frequently without special symptoms. This tumor has various characteristical histological patterns with different immunophenotype.     

Dynamic Changes in Serum Estradiol and Progesterone levels in Patients of Premenstrual Syndrome with Adverse Flow of Liver-qi

Objective:To probe into the influence of changes of ovarian hormones on the pathogenesis of the specific sub-type premenstrual syndrome(PMS)and reveal partial microcosmic mechanisms of adverse flow of liver-qi.Methods:Estradiol(E2)and progesterone(P)levels in serum were determined at different phases of menstrual cycle by radioimmunoassay.Results:In the group of PMS with adverse flow of liver-qi.the secretive peak value Of E2 and P at the follicular phase significantly decreased,and the secretive peak value at the luteal phase did not come into being.Conclusions:Low E2 and P secretive peak at the follicular phase and absence of secretive peak at the luteal phase is one of the microcosmic mechanisms of PMS with adverse flow of liver-qi.One of the pathophysiologic mechanisms of specific sub-type PMS is probably the continuous low level of E2and P.     

Real-time Three-dimensional Echocardiography in Assessment of Left Ventricular and Right Ventricular Volumes

Real-time three-dimensional echocardiography (RT3DE)is a new ultrasound technique that enables dynamic threedimensional visualization and quantification of the heart in real time. Investigation of feasibility and methodology of RT3DE in determining left ventricular (LV) and right ventricular (RV) volumes, RT3DE was performed in 35 normal adults using Philips SONOS 7500 system with a 2-4 MHz matrix array transducer. The 60°×60° "pyramid" volume database was obtained and analyzed on a TomTec echo workstation. Both LV and RV volumes were calculated with four 3DE methods (i.e. apical 2, 4, 8, and 16-plane) through manually tracing ventricular endocardial borders in end diastole and end systole. Stroke volumes were then calculated. LV volume was also measured by 2DE Simpson's rule using GE VIVID 7 ultrasound machine.     

SCREENING FOR A 21-CHROMOSOME ABNORMALITY IN PREIMPLANTED EMBRYOS OF ELDERLY WOMEN

Increasing maternal age is the only etiological factor unequivocally linked to Down's syndrome in humans. The occurrence rate of newborns with Down's syndrome is about 1/220 in women over 35 years old. However, the occurrence rate in embryos fertilized in vitro, of the elder woman is unclear. Using FISH we screened the number of chromosome 21 in preimplanted embryos of 5 elderly women (average age, 38.4 years) to study the feasibility and necessity of screening trisomy 21 in embryos in patients over 35 years old at the in vitro fertilization (IVF) center.