Prediction of Abdominal Visceral Obesity From Body Mass Index,Waist Circumference and Waist-hip Ratio in Chinese Adults:Receiver Operating Characteristic Curves Analysis

Objective To evaluate the sensitivity and specificity of body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) measurements in diagnosing abdominal visceral obesity. Methods BMI, WC, and WHR were assessed in 690 Chinese adults (305 men and 385 women) and compared with magnetic resonance imaging (MRI) measurements of abdominal visceral adipose tissue (VA). Receiver operating characteristic (ROC) curves were generated and used to determine the threshold point for each anthropometric parameter. Results 1) MRI showed that 61.7% of overweight/obese individuals (BMI≥25 kg/m2) and 14.2% of normal weight (BMI<25 kg/m2) individuals had abdominal visceral obesity (VA≥100 cm2). 2) VA was positively correlated with each anthropometric variable, of which WC showed the highest correlation (r=0.73-0.77, P<0.001). 3) The best cut-off points for assessing abdominal visceral obesity were as followed: BMI of 26 kg/m2, WC of 90 cm, and WHR of 0.93, with WC being the most sensitive and specific factor. 4) Among subjects with BMI≥28 kg/m2 or WC≥95 cm, 95% of men and 90% of women appeared to have abdominal visceral obesity. Conclusion Measurements of BMI, WC, and WHR can be used in the prediction of abdominal visceral obesity, of which WC was the one with better accuracy.

Determination of the diagnostic value of the resazurin reduction assay for evaluating boar semen by receiver operating characteristic analysis

Aim： To assess that metabolic status of spermatozoa could provide a useful tool for evaluation of semen quality. Methods： The accuracy of the spectrophotometric application of the resazurin reduction assay was assessed using receiver operating characteristic （ROC） analysis. Results： Areas under ROC curves （AUC） for motile sperm concentration and sperm index （SI） （sperm concentration multiplied by the square root of percentage sperm motility multiplied by the percentage normal sperm morphology） were 0.922. The best discrimination between poor and good semen samples according to the SI was achieved at a cut-off point of A610 = 0.209, where high sensitivity （94.1%） and specificity （91.7%） were calculated. The assay was less accurate when motile sperm concentration was used as the criterion value, yielding sensitivity of 88.2% and specificity of 87.5%, respectively. Likelihood ratios （LR） indicate that absorbances lower than 0.209 were at least 11.3 times as likely to be found in good semen samples than those in poor according to the SI, whereas in the case of motile sperm concentration, the LR was calculated to be 7.06. Conclusion： These results show that the resazurin reduction assay combined with spectrophotometry is an accurate method of assessing the quality of boar semen.

Preliminary Receiver Operating Characteristic Analysis on Voice Handicap Index of Laryngeal Inflammation in Greek Patients

Objective(s): Laryngeal inflammations lead to voice disorders. Medical conditions such as chronic laryngitis, gastroesophageal reflux, laryngopharyngeal reflux, Reinke edema and/or vocal folds hemorrhage, result in diverse symptoms including chronic cough, throat cleaning and dysphonia (e.g. hoarseness). In turn, the dysphonic symptoms can be evaluated via subjective and objective procedures. The objective procedures usually include self-perceived questionnaires like the Voice Handicap Index (VHI). Studies reported that VHI can distinguish objectively dysphonic and non-dysphonic populations using the cut-off points of Receiver Operating Characteristic Curves. The purpose of this study was to calculate the cut-off points for individuals exhibiting voice symptoms which had been developed from laryngeal inflammatory diseases in Greece. Methods: One hundred and twelve participants (90 non-dysphonic and 22 dysphonic) filled in the Hellenic Voice Handicap Index (VHI) and the Greek translated version of Voice Evaluation Template (VEF) were administrated. All subjects were evaluated by an Otolaryngologist and a Speech-Language Pathologist. Results: The group with voice disorders exhibited higher VHI scores (in total and in its 3 subdomains) compared to non-dysphonic subgroup. Statistical significant differences were found for all VHI’s total cut-off point of 19.50 (sensitivity: 0.882, 1-specificity: 0.011) and for its three subdomains [functional 6.50 (sensitivity = 0.636, and 1-specificity = 0.022);physical 9.50 (sensitivity = 0.636, and 1-specificity = 0.000);emotional 6.50 (sensitivity = 0.455, and 1-specificity = 0.133)]. Conclusion: The preliminary results showed that VHI could discriminate individuals having voice disorders from laryngeal inflammations. The Voice Handicap Index can be used as a primary health care tool and a self-monitoring procedure in acute and sub-acute phases of the laryngeal inflammation.

Optimal Weights in Nonparametric Analysis of Clustered ROC Curve Data

In diagnostic trials, clustered data are obtained when several subunits of the same patient are observed. Within-cluster correlations need to be taken into account when analyzing such clustered data. A nonparametric method has been proposed by Obuchowski (1997) to estimate the Receiver Operating Characteristic curve area (AUC) for such clustered data. However, Obuchowski’s estimator gives equal weight to all pairwise rankings within and between cluster. In this paper, we modify Obuchowski’s estimate by allowing weights for the pairwise rankings vary across clusters. We consider the optimal weights for estimating one AUC as well as two AUCs’ difference. Our results in this paper show that the optimal weights depends on not only the within-patient correlation but also the proportion of patients that have both unaffected and affected units. More importantly, we show that the loss of efficiency using equal weight instead of our optimal weights can be severe when there is a large within-cluster correlation and the proportion of patients that have both unaffected and affected units is small.

BOOTSTRAP TECHNIQUE FOR ROC ANALYSIS: A STABLE EVALUATION OF FISHER CLASSIFIER PERFORMANCE

This paper presents a novel bootstrap based method for Receiver Operating Characteristic (ROC) analysis of Fisher classifier. By defining Fisher classifier’s output as a statistic, the bootstrap technique is used to obtain the sampling distributions of the outputs for the positive class and the negative class respectively. As a result, the ROC curve is a plot of all the (False Positive Rate (FPR), True Positive Rate (TPR)) pairs by varying the decision threshold over the whole range of the boot- strap sampling distributions. The advantage of this method is, the bootstrap based ROC curves are much stable than those of the holdout or cross-validation, indicating a more stable ROC analysis of Fisher classifier. Experiments on five data sets publicly available demonstrate the effectiveness of the proposed method.

Study on Diagnosis Criteria of Fire-Heat Syndrome Based on Receiver Operating Characteristic Curve and Principal Component Analysis

Objective： To establish the diagnostic quantitative criteria for fire-heat syndrome （FHS） of Chinese medicine （CM） based on the receiver operating characteristic （ROC） curve and principal component analysis （PCA）. Methods： The symptoms and signs of FHS cases and healthy subjects from Guangzhou, Henan and Hunan of China were collected through questionnaire, and the diagnostic quantitative score tables were established for the three regions, respectively, with the method of maximum likelihood analysis. The homogeneity test was then performed on the diagnostic score tables for the three regions with ROC curve, and the diagnostic efficiency of diagnostic score tables for the three regions was compared with the prospective test and retrospective test. The method of PCA was adopted to obtain the analysis matrix for classifying the tapes of FHS. Results： Twenty-seven elements of FHS were confirmed through Chi-square test, and the diagnostic score tables for the three regions were established with the method of maximum likelihood analysis on the basis of the collected case data. According to the ROC curve test, the areas under ROC curve of Guangzhou diagnostic score table assessment with candidates in Guangzhou, Henan and Hunan were 0.998, 0.961 and 0.956, respectively. It showed that the diagnostic efficiency of Guangzhou diagnostic score tables was the highest one. With the prospective test, the area under ROC of Guangzhou diagnostic score table was 0.949, and more than any other diagnostic score table. By PCA, FHS was classified into excess fire and deficiency fire, and then classified into syndrome of flaring up of Heart （Xin） fire, syndrome of Lung （Fei）-Stomach （Wei） excess fire, syndrome of deficiency of Liver （Gan）-yin and Kidney （Shen）-yin, and syndrome of deficiency of Lung-yin from the view of viscera. In the retrospective test, the consistency with clinicians＇ diagnosis was 69.4%, and in the prospective test, it was 70.1%. Conclusions： The Guangzhou diagnostic score table could be used as the recommended criteria for the diagnosis of FHS. The classification of FHS was basically in conformity with the clinical situation.

Nomogram for predicting lymph node metastasis rate of submucosal gastric cancer by analyzing clinicopathological characteristics associated with lymph node metastasis

Background： To combine dinicopathological characteristics associated with lymph node metastasis for submucosal gastric cancer into a nomogram. Methods： We retrospectively analyzed 262 patients with submucosal gastric cancer who underwent D2 gastrectomy between 1996 and 2012. The relationship between lymph node metastasis and clinicopathological features was statistically analyzed. With multivariate logistic regression analysis, we made a nomogram to predict the possibility of lymph node metastasis. Receiver operating characteristic （ROC） analysis was also performed to assess the predictive value of the model. Discrimination and calibration were performed using internal validation. Results： A total number of 48 （18.3%） patients with submucosal gastric cancer have pathologically lymph node metastasis. For submucosal gastric carcinoma, lymph node metastasis was associated with age, tumor location, macroscopic type, size, differentiation, histology, the existence of ulcer and lymphovascular invasion in univariate analysis （all P〈0.05）. The multivariate logistic old, macroscopic type III or mixed, undifferentiated type, regression analysis identified that age _〈50 years and presence of lymphovascular invasion were independent risk factors of lymph node metastasis in submucosal gastric cancer （all P〈0.05）. We constructed a predicting nomogram with all these factors for lymph node metastasis in submucosal gastric cancer with good discrimination [area under the curve （AUC） =0.844]. Internal validation demonstrated a good discrimination power that the actual probability corresponds closely with the predicted probability. Conclusions： We developed a nomogram to predict the rate of lymph node metastasis for submucosal gastric cancer. With good discrimination and internal validation, the nomogram improved individualized predictions for assisting clinicians to make appropriated treatment decision for submucosal gastric cancer patients.

A meta-analysis for assessing the value of MR spectroscopy in the diagnosis of prostate cancer

Objective: To assess the value of MR spectroscopy (MRS) in the diagnosis of prostate cancer by meta-analysis. Methods: Prospective studies were selected from the MEDLINE, Ovid, Embase databases. Springer, Elsevier, China National Knowledge Infrastructure. According to the suggestion, results were determined by the ratio of (Cho + Cr)/Cit . If this ratio was less than 0. 75, negative result was respectively determined, and the definitive tumor was diagnosed as this threshold. According to the assessment standard of Evidence-based Medicine, English and Chinese literature in Grade A and B on MRS imaging was included. According to homogeneity test, different effect models were chosen to calculate different pooled weighted values of sensitivity, specificity and the corresponding 95% confidence intervals (95% CD. Summary receiver operating characteristic (SROC) curves were used to assess the results. Funnel plot was used to analyze publication bias. Results: According to the assessment standard of Evidence-based Medicine, only 5 papers in Grade B were included in this research. The pooled weighted sensitivity and its 95% confidence interval is 82%(73%, 89%) and the pooled weighted sensitivity and its 95% confidence interval is 68% (58%, 76%). The AUC (area under curve) is 83. 40%. An asymmetric funnel plot suggested two missing studies leading to publication bias. Conclusion: If the ratio of (Cho + Cr)/Cit is regarded as the diagnostic criteria in detecting prostate cancer by MRS, meta-analysis suggests this method has a better diagnostic value to detect the malignant prostate mass but the sensitivity needs to be improved. We hope to support a method and requirement about diagnostic test. Performing perspective register and improving quality of study design is the only way to reduce the bias and get real information of disease.

基于ROC曲线分析子宫动脉超声联合超声心动图预测子痫前期的价值

目的基于ROC曲线分析子宫动脉超声及超声心动图联合预测子痫前期的价值。方法选择2021年1月至2022年6月进行产检后评估为低风险的314例初产妇为研究对象,均行子宫动脉超声、超声心动图检查,根据最终妊娠结局分为正常组(271例)和病例组(43例)。统计病例组中子痫前期产妇例数,比较正常组和子痫前期产妇的子宫动脉超声、超声心动图检查参数的差异。结果病例组43例中子痫前期22例,子痫前期产妇的子宫动脉超声检查参数[血流速度峰谷比(S/D)、阻力指数(RI)、血流搏动指数(PI)]均高于正常组(P<0.05);子痫前期产妇的超声心动图检查参数[左心室舒张末期内径(LVDd)、左心室收缩末期内径(LVDs)、舒张晚期最大流速(A峰)]均大于对照组(P<0.05),左心室射血分数(LVEF)、缩短分数(FS)、舒张早期最大流速(E峰)以及E/A比值均低于对照组(P<0.05)。ROC曲线分析发现,子宫动脉超声及超声心动图联合预测子痫前期的效果比单独预测好(P<0.05)。结论基于ROC曲线分析显示,子宫动脉超声联合超声心动图对子痫前期具有良好的预测价值,值得推广。

手助腹腔镜下活体供肾切取手术时间的影响因素及其与术后并发症的关系分析

目的探究手助腹腔镜下活体供肾切取手术时间的影响因素,并探究其与术后并发症严重程度间的关系。方法回顾性分析91例行手助腹腔镜下活体供肾切取术的供者的临床资料,分析供者术前基线资料与手术时间之间的相关性,研究手术时间与术后并发症的关系并确定手术时间的阈值。结果肾动脉数量多、肾周脂肪及肾脏后侧脂肪较厚、罹患代谢综合征、梅奥粘连概率(MAP)评分及Clavien-Dindo评分较高均会导致手术时间延长。通过分析受试者工作特征(ROC)曲线发现,当手术时间≥138 min时,供者术后并发症的发生率显著升高(P<0.05)。结论对于具有多支肾动脉、肾周及肾脏后侧脂肪厚度较厚、罹患代谢综合征、MAP评分及Clavien-Dindo评分较高的供者,可选择手术经验更为丰富的医师,做好充分的术前准备并在术后予以密切关注,以及时发现术后并发症并降低并发症的严重程度,改善供者预后。

应用ROC曲线评价N末端B型脑钠肽(NT-proBNP)及生化指标在心血管疾病中的诊断价值

目的评价N末端B型脑钠肽(NT-proBNP)、同型半胱氨酸(Hcy)、超敏肌钙蛋白T(cTnT)、肌钙蛋白I(cTnI)及其他生化项目对心血管疾病的诊断价值。方法应用受试者工作特征曲线(ROC)对131例心血管疾病患者、43例单纯性高血压患者和61例健康对照者的血清NT-proBNP、Hcy及cTnT、cTnI及其他生化指标进行分析,并对心血管疾病组患者NT-proB-NP与心功能分级进行相关性研究。结果 NT-proBNP、Hcy、cTnT、cTnI、CK-MB的水平在心血管病组和对照组两组间差异有统计学意义(P<0.05);NT-proBNP、cTnT、cTnI、CK-MB在心血管病组和高血压病组间存在统计学差异(P<0.05)。急性心肌梗死、风湿性心脏病、肺源性心脏病、心肌炎病患者血清NT-proBNP水平显著高于心绞痛、先天性心脏病、心律不齐等其他心血管病患者。NT-proBNP、cTnT、cTnI、CK-MB的ROC曲线下面积(AUC)分别为0.767,0.745,0.734,0.715。心血管病患者血清NT-proBNP、cTnT、cTnI、CK-MB水平与心血管病患者心功能分级间呈显著正相关,相关系数分别为0.912,0.891,0.816,0.718,均P<0.05。结论 NT-proBNP、cTnT、cTnI、CK-MB是临床诊断心血管疾病的有价值指标。

Logistic回归及ROC曲线综合评价CA15-3、CA125、CK19、CEA、AFP和CA199在乳腺癌术后监测中的应用价值

目的:应用Logistic回归模型及受试者工作特征曲线(Receiver operating characteristic curve,ROC曲线)探讨多种血清肿瘤标志物在乳腺癌术后监测中的应用价值。方法:采用化学发光免疫分析法测定34例术后复发转移患者及76例无复发患者的血清CA15-3、CA125、CK19、CEA、AFP、CA199水平,通过组间均值比较和Logistic逐步回归分析筛选出有效指标,并通过ROC曲线评价其在术后复发转移判断中的诊断价值。结果:其中3项血清肿瘤标志物CA15-3、CK19和CEA入选Logistic回归方程,对应的曲线下面积分别为0.974、0.922、0.913,阳性检出率分别为82.4%、73.5%和64.7%。结论:肿瘤标志物CA15-3、CK19、CEA在术后复发或转移诊断中有较高的应用价值,可作为乳腺癌术后监测复发转移的有效指标。

SPSS中的ROC分析用于检验/诊断方法的评价

[目的 ]介绍如何用SPSS软件包中新颖的ROC分析法 ,来对一种或几种检验 /诊断方法进行科学评价。[方法 ]回顾目前文献中的存在问题 ;对四格表排列、数据库录入以及ROC命令默认设置提出应用或改变建议 ;举例说明定性、定量资料的ROC分析方法 ;介绍 2或 3种诊断方法诊断效能比较的ROC分析方法与结果 ;ROC分析结果与列联表分析、logistic回归及判别分析结果相印证。[结果 ]按本文建议 ,ROC分析能方便地对一种或几种检验 /诊断方法进行科学评价 ,算出其敏感性与特异性等 6项指标 ,且与其他 3种分析方法统一、对应。 [结论 ]ROC曲线能将诊断方法的敏感性与特异性结合起来进行分析 ,而不是仅侧重于其敏感性或特异性 ,又能表示为“曲线下的面积越大 ,其诊断试验效果越好” ,既全面又直观 ,又与其他统计分析方法结果对应、统一 ,值得在检验

基于ROC曲线的弹道目标识别评估及优化

分析了弹道目标识别的特点,指出弹道真假目标识别在本质上是一个风险最小的寻优过程,等同于Neyman-Pearson决策。在此基础上,提出采用ROC曲线下的面积(AUC)对识别方法进行评估,介绍了AUC的两种计算方法。进一步,提出采用AUC对识别器进行比较及优化,介绍了ROC凸包的基本概念并将其用于识别器优化。进行了相应的仿真实验,结果表明了所提出方法的可行性。

基于ROC分析的Canny算法在景象匹配中的应用

根据ROC分析方法能对分类识别算法进行多门限评估的特点,利用其改进Canny算法性能并应用于景象匹配。首先由不同参数组合的Canny算子计算图像的多个边缘提取图,并逐像素进行统计,得到边缘像素相关图;然后采用ROC曲线分析找到最佳的关联阈值,从而确定理论边缘图;最后将参考图与实时图所对应的理论边缘图进行景象匹配。实验结果表明,该方法在参考图和实时图存在一定几何畸变和灰度差异的情况下,能取得较高的平均匹配精度与正确匹配概率。此外,该方法克服了传统Canny算子采用固定参数的缺点,根据多参数自动进行筛选优化,有较强的工程实用性。

打印介质对肺孤立小结节诊断准确性影响的ROC分析：纸介打印与干式激光打印对比

目的探讨纸质打印片及干式激光打印胶片对于数字化胸片上孤立性肺结节诊断准确性的影响。方法分别采用LOCUS纸质打印机及KONICA DRYPRO 752干式激光打印机打印数字化正位胸片。由4位(具有3年工作经验和具有10年以上工作经验医师各2位)放射科医师分别对于50例正位胸片进行读片。读片分两次进行,两次读片间隔三周。每次读片分别采用其中的一种打印形式进行读片。读片结果采用LABMR软件进行ROC分析,绘制ROC曲线。结果采用两种方式读片时,结果无显著性差异,干式激光打印胶片图像诊断结果与纸质打印片之间无显著性差异。结论对于孤立性肺结节的诊断,干式激光打印胶片诊断准确率与纸质打印片之间无显著性差异。

应用ROC曲线制定XE-2100血液分析仪的白细胞分类复检标准

目的应用ROC曲线分析建立XE-2100血液分析仪白细胞分类(difference of cell,DC)的复检标准。方法以手工法为金标准,对416份患者分别进行仪器和手工计数分类,对仪器结果进行判断,应用ROC(receiver operating char-acteristic curve)建立DC的复检标准,并评价复检标准。结果白细胞分类的复检标准为中性粒细胞(N)>75%、淋巴细胞(L)>45%、嗜酸性粒细胞(Eo)>10%、嗜碱性粒细胞(B)>2%、单核细胞(M)>13%;血细胞形态异常:原始细胞(Blast)或异常淋巴细胞(Abn-BL)报警且研究参数other>2%、或变异淋巴(AtypicalLy)报警且L≥50%且M≥13%,IG报警且研究参数IG>3%、NRBC(有核红细胞)报警且N≥2个/100WBC。结论仪器对M、B、血细胞形态异常的报警提示较为敏感,建立适当的复检标准可以减少白细胞分类的复检率,提高实验室的工作效率。

基于OCTA构建糖尿病肾脏病临床预测模型

【目的】探讨基于光学相干断层扫描血管成像技术(OCTA),筛查糖尿病肾脏病(DKD)高风险人群的临床预测模型。【方法】本研究以567例糖尿病患者为研究对象,在逐步logistic回归分析的基础上,运用随机森林算法筛选纳入建模的指标,构建基于OCTA糖尿病肾脏病临床预测模型。通过受试者工作特征曲线评价模型区分度,通过决策曲线分析评估模型临床有效性。【结果】构建基于OCTA的DKD临床预测模型,ROC曲线下面积为0.878,Brier=0.11。【结论】本研究构建了基于OCTA结果进行糖尿病肾脏病临床预测的列线图预测模型,并从多维度验证模型,从而达到早期预警、提前实施干预的目的。

基于ROC的三元再编码研究

针对三元编码矩阵中基分类器不包含被忽略样本类别先验知识的问题,该文提出一种基于接收机工作特性(ROC)曲线的矩阵再编码方法。首先基于ROC曲线寻找构造拒绝域的阈值对,从而获得最优分类器;然后利用最优分类器对训练样本中被忽略的类别进行分类,将经典的二值输出变为三值输出,从而对初始编码矩阵的码元"0"进行重新编码。在解码阶段,采用经典的汉明距离解码方法对未知样本进行决策。该方法能够避免基分类器的二次训练,适用于任意的三元纠错输出编码,具有良好的普适性和实用性。基于人工和UCI公共数据集的实验结果表明该方法简单高效,在不增加训练时间的基础上,能够提高解码的速度和精度,促进分类效果的提升。

ROC分析及其在fMRI信号中的一个应用

详细阐述了受试者工作特征(Receiver operating characteristic,ROC)分析的基本原理,分析了它与其它的诊断评价性标准相比存在的优点,并给出了ROC曲线的绘制方法,最后采用ROC对独立成分分析(Independent component analysis,ICA)和统计参数图(Statistical parametric mapping,SPM)处理功能磁共振成像(Functional magnetic reasonance imaging,fMRI)数据的结果进行了比较。