期刊文献+
共找到1,124篇文章
< 1 2 57 >
每页显示 20 50 100
Synthetically quantitative evaluation function of characteristic parameters on CO_2 arc welding process 被引量:4
1
作者 俞建荣 蒋力培 +2 位作者 史耀武 孙振国 王军波 《China Welding》 EI CAS 2001年第1期19-26,共8页
The statistical probability and their variation regularity of the measurable characteristic parameters in the CO 2 arc welding droplet short circuiting transfer process have been studied. The statistical analysis sh... The statistical probability and their variation regularity of the measurable characteristic parameters in the CO 2 arc welding droplet short circuiting transfer process have been studied. The statistical analysis shows that the sensitivity of each characteristic parameter with regard to the variation of the short circuiting transfer process is different. The sensitivity of 4 kinds among these characteristic parameters is more intense than that of the short circuiting transfer frequency. In order to take account of the synthetic influence of these characteristic parameters, by means of the characteristic parameters synthetic value, a quantitative evaluation function is built up to describe and evaluate the short circuiting transfer process of CO 2 arc welding in real time. The testing shows that the evaluation function can give a suitable synthetic valuation for the short circuiting transfer process with a variety of welding variables. 展开更多
关键词 CO 2 arc welding process characteristic parameters quantitative evaluation function
在线阅读 下载PDF
Quantitative parameters in novel spectral computed tomography:Assessment of Ki-67 expression in patients with gastric adenocarcinoma 被引量:8
2
作者 Li-Ting Mao Wei-Cui Chen +6 位作者 Jian-Ye Lu Han-Liang Zhang Yong-Song Ye Yu Zhang Bo Liu Wei-Wei Deng Xian Liu 《World Journal of Gastroenterology》 SCIE CAS 2023年第10期1602-1613,共12页
BACKGROUND The level of Ki-67 expression has served as a prognostic factor in gastric cancer.The quantitative parameters based on the novel dual-layer spectral detector computed tomography(DLSDCT)in discriminating the... BACKGROUND The level of Ki-67 expression has served as a prognostic factor in gastric cancer.The quantitative parameters based on the novel dual-layer spectral detector computed tomography(DLSDCT)in discriminating the Ki-67 expression status are unclear.AIM To investigate the diagnostic ability of DLSDCT-derived parameters for Ki-67 expression status in gastric carcinoma(GC).METHODS Dual-phase enhanced abdominal DLSDCT was performed preoperatively in 108 patients with gastric adenocarcinoma.Primary tumor monoenergetic CT attenuation value at 40-100 kilo electron volt(kev),the slope of the spectral curve(λ_(HU)),iodine concentration(IC),normalized IC(nIC),effective atomic number(Z^(eff))and normalized Z^(eff)(nZ^(eff))in the arterial phase(AP)and venous phase(VP)were retrospectively compared between patients with low and high Ki-67 expression in gastric adenocarcinoma.Spearman’s correlation coefficient was used to analyze the association between the above parameters and Ki-67 expression status.Receiver operating characteristic(ROC)curve analysis was performed to compare the diagnostic efficacy of the statistically significant parameters between two groups.RESULTS Thirty-seven and 71 patients were classified as having low and high Ki-67 expression,respectively.CT_(40 kev-VP),CT_(70 kev-VP),CT_(100 kev-VP),and Z^(eff)-related parameters were significantly higher,but IC-related parameters were lower in the group with low Ki-67 expression status than the group with high Ki-67 expression status,and other analyzed parameters showed no statistical difference between the two groups.Spearman’s correlation analysis showed that CT_(40 kev-VP),CT_(70 kev-VP),CT_(100 kev-VP),Z^(eff),and n Z^(eff) exhibited a negative correlation with Ki-67 status,whereas IC and nIC had positive correlation with Ki-67 status.The ROC analysis demonstrated that the multi-variable model of spectral parameters performed well in identifying the Ki-67 status[area under the curve(AUC)=0.967;sensitivity 95.77%;specificity 91.89%)].Nevertheless,the differentiating capabilities of singlevariable model were moderate(AUC value 0.630-0.835).In addition,the nZ_(VP)^(eff) and nIC_(VP)(AUC 0.835 and 0.805)showed better performance than CT_(40 kev-VP),CT_(70 kev-VP) and CT_(100 kev-VP)(AUC 0.630,0.631 and 0.662)in discriminating the Ki-67 status.CONCLUSION Quantitative spectral parameters are feasible to distinguish low and high Ki-67 expression in gastric adenocarcinoma.Z^(eff) and IC may be useful parameters for evaluating the Ki-67 expression. 展开更多
关键词 Spectral computer tomography quantitative parameters Gastric carcinoma Iodine concentration Effective atomic number Ki-67 expression
暂未订购
Quantitative determination of PFC3D microscopic parameters 被引量:7
3
作者 LI Zhuo RAO Qiu-hua 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第3期911-925,共15页
It is important to calibrate micro-parameters for applying partied flow code(PFC)to study mechanical characteristics and failure mechanism of rock materials.Uniform design method is firstly adopted to determine the mi... It is important to calibrate micro-parameters for applying partied flow code(PFC)to study mechanical characteristics and failure mechanism of rock materials.Uniform design method is firstly adopted to determine the microscopic parameters of parallel-bonded particle model for three-dimensional discrete element particle flow code(PFC3D).Variation ranges of microscopic of the microscopic parameters are created by analyzing the effects of microscopic parameters on macroscopic parameters(elastic modulus E,Poisson ratio v,uniaxial compressive strengthσc,and ratio of crack initial stress to uniaxial compressive strengthσci/σc)in order to obtain the actual uniform design talbe.The calculation equations of the microscopic and macroscopic parameters of rock materials can be established by the actual uniform design table and the regression analysis and thus the PFC3D microscopic parameters can be quantitatively determined.The PFC3D simulated results of the intact and pre-cracked rock specimens under uniaxial and triaxial compressions(including the macroscopic mechanical parameters,stress−strain curves and failure process)are in good agreement with experimental results,which can prove the validity of the calculation equations of microscopic and macroscopic parameters. 展开更多
关键词 quantitative relationship of microscopic and macroscopic parameters uniform design method three-dimensional particle flow code(PFC3D) ROCK
在线阅读 下载PDF
Variation on Wild Sunflower (Helianthus ruderalis L.) for Quantitative and Qualitative Parameters 被引量:2
4
作者 S. A. Aliu S. Sh. Fetahu S. Xh. Kaqiu H. E. Bytyci 《Journal of Agricultural Science and Technology》 2010年第3期11-17,共7页
Our expedition have identified location in the central part of Kosovo where were collected a samples (accessions) at coordinates; Sub-Locality SL-1 (N42°34′36″, E21°07′45″), altitude 574 m, SL-2 (N4... Our expedition have identified location in the central part of Kosovo where were collected a samples (accessions) at coordinates; Sub-Locality SL-1 (N42°34′36″, E21°07′45″), altitude 574 m, SL-2 (N42°34′29″, E 21°07′45″altitude 591 m and SL-3 (N42°34′30″, E21°07′46″) on altitude 565 m. The aim of present investigation was carried out to study genetic variability of quantitative and qualitative parameters. The populations from SL-2 were characterized of higher significance on seed oil (23.74%) and protein content (16.74%). The estimation average value of seed protein and oil content was 15.52% and 23.48% respectively. The variability of plant height ranged from 182.33 cm to as much as 200.89 cm, while distinction's between them were + 18.56 cm which was a significant higher at P〈0.05 probability level. The SL-3 showed the higher value of HWK (34.6 g), head per plant (39.33) and head diameter (9.5 cm) but, was characterized significantly lowest on seed protein content (13.99%). The all traits included in our investigations showed a higher genetic variability with majority of extreme values. The sunflower populations differed significantly in several parameters measured, they have a different genetic and morphological backgrounds. Results from wild sunflower form indicated notable differences in dispersion of important genes for different traits and showed the potential for using in future for breeding program. 展开更多
关键词 SUNFLOWER ACCESSION quantitative parameters oil content protein content.
在线阅读 下载PDF
The quantitative check-measure of the bend strain parameters of the rotating components
5
作者 李文华 乔中涛 《Journal of Coal Science & Engineering(China)》 2002年第1期79-81,共3页
Based on the principle of the electric-magnetic check-measure, this paper puts forward a new technology and method that use the magnetic marks to check and measure the dynamic physical parameters such as angle speed, ... Based on the principle of the electric-magnetic check-measure, this paper puts forward a new technology and method that use the magnetic marks to check and measure the dynamic physical parameters such as angle speed, bending strain,stress and bending moment. The principles of the check-measure and the dealing and exchanging technology about signals have been demonstrated and the rotating components have been made up. The timely and quantitative check-measure of the dynamic physical parameters during the component in working has been realized by using computer control. 展开更多
关键词 rotating component dynamic parameter quantitative check-measure
在线阅读 下载PDF
Quantitative evaluation methods for waterflooded layers of conglomerate reservoir based on well logging data 被引量:22
6
作者 Tan Fengqi Li Hongqi +2 位作者 Xu Changfu Li Qingyuan Peng Shouchang 《Petroleum Science》 SCIE CAS CSCD 2010年第4期485-493,共9页
The rapid changing near source, multi-stream depositional environment of conglomerate reservoirs leads to severe heterogeneity, complex lithology and physical properties, and large changes of oil layer resistivity. Qu... The rapid changing near source, multi-stream depositional environment of conglomerate reservoirs leads to severe heterogeneity, complex lithology and physical properties, and large changes of oil layer resistivity. Quantitative evaluation of water-flooded layers has become an important but difficult focus for secondary development of oilfields. In this paper, based on the analysis of current problems in quantitative evaluation of water-flooded layers, the Kexia Group conglomerate reservoir of the Sixth District in the Karamay Oilfield was studied. Eight types of conglomerate reservoir lithology were identified effectively by a data mining method combined with the data from sealed coring wells, and then a multi-parameter model for quantitative evaluation of the water-flooded layers of the main oil-bearing lithology was developed. Water production rate, oil saturation and oil productivity index were selected as the characteristic parameters for quantitative evaluation of water-flooded layers of conglomerate reservoirs. Finally, quantitative evaluation criteria and identification rules for water-flooded layers of main oil-bearing lithology formed by integration of the three characteristic parameters of water-flooded layer and undisturbed formation resistivity. This method has been used in evaluation of the water-flooded layers of a conglomerate reservoir in the Karamay Oilfield and achieved good results, improving the interpretation accuracy and compliance rate. It will provide technical support for avoiding perforation of high water-bearing layers and for adjustment of developmental programs. 展开更多
关键词 Water-flooded layer quantitative evaluation conglomerate reservoir lithology identification decision tree characteristic parameters
原文传递
Measurement of Plasma Parameters of Calcium and Silicon in a Rock Sample Using Laser Induced Breakdown Spectroscopy 被引量:4
7
作者 Uzma G M.Junaid +1 位作者 Khalid Alamgir T Samina 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2017年第10期3266-3269,共4页
Laser Induced Breakdown Spectroscopic(LIBS)technique was used to detect calcium and silicon in an unknown sample.In this method plasma was generated by Nd∶YAG laser of wavelength 1 064 nm with energy 400 mJ and pulse... Laser Induced Breakdown Spectroscopic(LIBS)technique was used to detect calcium and silicon in an unknown sample.In this method plasma was generated by Nd∶YAG laser of wavelength 1 064 nm with energy 400 mJ and pulse duration between 5~10ns.The method was applied for the qualitative as well as quantitative analysis.In the qualitative analysis,the electron number density(Ne)of plasma containing calcium and silicon is determined showing that Neof neutral particles is equivalent to 1016(cm-3)whereas for ionized particles it is 1017(cm-3).Plasma temperature is measured using Boltzmann plot method which must be greater than 10 000 k.Intensity ratio method is used for the quantitative analysis shows various elements in abundance with calcium and silicon in majority. 展开更多
关键词 LIBS Plasma parameter quantitative analysis Qualitative analysis
在线阅读 下载PDF
甲状腺良恶性病变患者SPECT-CT定量参数表达差异与血管生成的相关性
8
作者 李唯 蔡淑云 +3 位作者 宣建新 赵明 郑义 滕伟 《影像科学与光化学》 2025年第6期114-119,共6页
目的:探究甲状腺良恶性病变患者SPECT-CT定量参数与血管生成的相关性。方法:选取2022年1月至2023年12月于本院就诊的甲状腺良恶性病变患者121例,分为良性病变组(n=91)和恶性病变组(n=30)。对比两组的SPECT-CT定量参数(甲状腺体积、SUVm... 目的:探究甲状腺良恶性病变患者SPECT-CT定量参数与血管生成的相关性。方法:选取2022年1月至2023年12月于本院就诊的甲状腺良恶性病变患者121例,分为良性病变组(n=91)和恶性病变组(n=30)。对比两组的SPECT-CT定量参数(甲状腺体积、SUVmean、SUVmax、锝摄取功率、FTM)及血管生成指标(VEGF、EGFR、Ang-2)。采用Pearson相关分析两者之间的相关性。结果:恶性病变组的各项SPECT-CT定量参数及血管生成指标均显著高于良性病变组(P<0.05,通过t检验得出)。SPECT-CT定量参数与血管生成呈正相关。结论:SPECT-CT定量参数的异常升高与血管生成有显著相关性。 展开更多
关键词 甲状腺良恶性病变 spect-ct定量参数 血管生成 相关性分析
暂未订购
Quantitative design of yield components to simulate yield formation for maize in China 被引量:4
9
作者 HOU Hai-peng MA Wei +4 位作者 Mehmood Ali NOOR TANG Li-yuan LI Cong-feng DING Zai-song ZHAO Ming 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2020年第3期668-679,共12页
Maize(Zea mays L.) stands prominently as one of the major cereal crops in China as well as in the rest of the world.Therefore,predicting the growth and yield of maize for large areas through yield components under hig... Maize(Zea mays L.) stands prominently as one of the major cereal crops in China as well as in the rest of the world.Therefore,predicting the growth and yield of maize for large areas through yield components under high-yielding environments will help in understanding the process of yield formation and yield potential under different environmental conditions.This accurate early assessment of yield requires accuracy in the formation process of yield components as well.In order to formulate the quantitative design for high yields of maize in China,yield performance parameters of quantitative design for high grain yields were evaluated in this study,by utilizing the yield performance equation with normalization of planting density.Planting density was evaluated by parameters including the maximum leaf area index and the maximum leaf area per plant.Results showed that the variation of the maximum leaf area per plant with varying plant density conformed to the Reciprocal Model,which proved to have excellent prediction with root mean square error(RMSE) value of 5.95%.Yield model estimation depicted that the best optimal maximum leaf area per plant was 0.63 times the potential maximum leaf area per plant of hybrids.Yield performance parameters for different yield levels were quantitatively designed based on the yield performance equation.Through validation of the yield performance model by simulating high yields of spring maize in the Inner Mongolia Autonomous Region and Jilin Province,China,and summer maize in Shandong Province,the yield performance equation showed excellent prediction with the satisfactory mean RMSE value(7.72%) of all the parameters.The present study provides theoretical support for the formulation of quantitative design for sustainable high yield of maize in China,through consideration of planting density normalization in the yield prediction process,providing there is no water and nutrient limitation. 展开更多
关键词 MAIZE yield performance parameters high yield yield prediction process quantitative design
在线阅读 下载PDF
Calculation of Hildebrand Solubility Parameters of Some Polymers Using QSPR Methods Based on LS-SVM Technique and Theoretical Molecular Descriptors 被引量:3
10
作者 Nasser Goudarzi M.Arab Chamjangali A.H.Amin 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2014年第5期587-594,共8页
In this work, some chemometrics methods are applied for the modeling and prediction of the Hildebrand solubility parameter of some polymers. A genetic algorithm (GA) method is designed for the selection of variables... In this work, some chemometrics methods are applied for the modeling and prediction of the Hildebrand solubility parameter of some polymers. A genetic algorithm (GA) method is designed for the selection of variables to construct two models using the multiple linear regression (MLR) and least square-support vector machine (LS-SVM) methods in order to predict the Hildebrand solubility parameter. The MLR method is used to build a linear relationship between the molecular descriptors and the Hildebrand solubility parameter for these compounds. Then the LS-SVM method is utilized to construct the non-linear quantitative structure-activity relationship (QSAR) models. The results obtained using the LS-SVM method are then compared with those obtained for the MLR method; it was revealed that the LS-SVM model was much better than the MLR one. The root-mean-square errors of the training set and the test set for the LS-SVM model were 0.2912 and 0.2427, and the correlation coefficients were 0.9662 and 0.9518, respectively. This paper provides a new and effective method for predicting the Hildebrand solubility parameter for some polymers, and also reveals that the LS-SVM method can be used as a powerful chemometrics tool for the quantitative structure-property relationship (QSPR) studies. 展开更多
关键词 Hildebrand solubility parameter Least square-support vector machine (LS-SVM) quantitative structure- property relationship (QSPR) Multiple linear regression (MLR) Genetic algorithm (GA).
原文传递
Quantitative feedback theory and zero phase error tracking control combined robust control for radar truck leveling simulator 被引量:1
11
作者 凌轩 李晓辉 +1 位作者 朱玉泉 冯天麟 《Journal of Shanghai University(English Edition)》 2009年第5期384-390,共7页
Radar leveling system is the key equipment for improving the radar mobility and survival capability. A combined quantitative feedback theory (QFT) controller is designed for the radar truck leveling simulator in this ... Radar leveling system is the key equipment for improving the radar mobility and survival capability. A combined quantitative feedback theory (QFT) controller is designed for the radar truck leveling simulator in this paper, which suffers from strong nonlinearities and system parameter uncertainties. QFT can reduce the plant uncertainties and stabilize the system, but it fails to obtain high-precision tracking. This drawback can be solved by a robust QFT control scheme based on zero phase error tracking control (ZPETC) compensation. The combined controller not only possesses high robustness, but greatly improves the system performance. To verify the effiectiveness and the potential of the proposed controller, a series of experiments have been carried out. Experimental results have demonstrated its robustness against a large range of parameters variation and high tracking precision performance, as well as its capability of restraining the load coupling among channels. The combined QFT controller can drive the radar truck leveling platform accurately, quickly and stably. 展开更多
关键词 radar truck leveling simulator quantitative feedback theory (QFT) parameter uncertainties zero phase error tracking control (ZPETC) high robustness
在线阅读 下载PDF
Quantitative comparison screening of seismological indexes and research on the integrated prediction method in North China
12
作者 周翠英 朱元清 +3 位作者 王红卫 梁凯莉 李平 郭爱香 《Acta Seismologica Sinica(English Edition)》 CSCD 1999年第2期232-237,共6页
关键词 comparison screening method quantitative selecting SEISMOLOGY parameters INTEGRATED Prediction
在线阅读 下载PDF
Quantitative Analysis of Glomeruli Lesions in Patients with Mesangial Proliferative Glomerulonephritis
13
作者 孙建平 王韵琴 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 1996年第2期106-110,共5页
By using computer imaging analysis system combined with light microscopy, the glomeruli lesions on biopsy specimens sections were quantitatively analysed. The patholoical changes of mesangial proliferative glomerulone... By using computer imaging analysis system combined with light microscopy, the glomeruli lesions on biopsy specimens sections were quantitatively analysed. The patholoical changes of mesangial proliferative glomerulonephritis (MsPGN) in children were quantitatively evaluated and the correlation between the mesangial matrix area (MA) and some clinical data were also analysed. The results indicated that the levels of various glomerular parameters in MsPGN group were higher than those of normal controls. No correlation was found between MA and 24 h urinary protein excretion, but a negative correlation was revealed between MA and estimated GFR. MA was also correlated with the duration of MsPGN recovery. It was suggested that the quantitative analysis of glomerular parameters by computer is a reproducible methods. The parameter of MA may be used for evaluation of the renal function, determination of the duration of therapy and evaluation of prognosis of MsPGN in children. 展开更多
关键词 quantitative analysis computer imaging analysis system glomerular parameters
暂未订购
超声造影定量参数联合C反应蛋白/白蛋白比率对颈动脉粥样硬化并发缺血性脑卒中的预测价值分析
14
作者 谢迎新 赵雅培 +2 位作者 薛丽丽 刘晓松 杨翠英 《脑与神经疾病杂志》 2026年第1期12-17,共6页
目的探讨超声造影定量参数联合C反应蛋白/白蛋白比率(CRP/Alb)对颈动脉粥样硬化(CAS)并发缺血性脑卒中(IS)的预测价值。方法回顾性分析2020年5月至2022年7月于河北医科大学第二医院鹿泉院区诊治的100例CAS患者作为观察组,并根据是否并... 目的探讨超声造影定量参数联合C反应蛋白/白蛋白比率(CRP/Alb)对颈动脉粥样硬化(CAS)并发缺血性脑卒中(IS)的预测价值。方法回顾性分析2020年5月至2022年7月于河北医科大学第二医院鹿泉院区诊治的100例CAS患者作为观察组,并根据是否并发IS分为发生组(n=36)与未发生组(n=64)。同时收集20例健康体检者作为对照组。对比两组的基线资料、超声造影定量参数[时间-强度曲线(TIC)-强度峰值(PI)、达峰时间(TTP)、TIC-曲线下面积(TIC-AUC)、平均渡越时间(MTT)]、C反应蛋白(CRP)、白蛋白(Alb)计数、CRP/Alb。经Spearman秩相关性分析超声造影定量参数、CRP/Alb与CAS患者发生IS的相关性,经多因素Logistic回归分析CAS患者发生IS的影响因素,最后经ROC曲线分析超声造影定量参数、CRP/Alb对CAS患者发生IS的预测价值。结果观察组的TIC-PI、TIC-AUC、CRP、CRP/Alb均明显高于对照组(P<0.05),观察组TTP、Alb水平均显著低于对照组(P<0.05);发生组的TIC-PI、TIC-AUC、CRP、CRP/Alb均明显高于未发生组(P<0.05),发生组的TTP、Alb水平均显著低于未发生组(P<0.05);Spearman秩相关分析显示,TIC-PI、TIC-AUC、CRP/Alb与CAS患者发生IS呈正相关(r=0.431、0.603、0.806,P<0.05),TTP与CAS患者发生IS呈负相关(r=-0.635,P<0.05);多因素Logistic回归分析显示,TIC-PI、CRP/Alb是CAS患者发生IS的独立危险因素(P<0.05),TTP为CAS患者发生IS的独立保护因素(P<0.05);ROC曲线分析结果显示,TIC-PI、TTP、CRP/Alb预测CAS患者发生IS的AUC分别为0.714、0.733、0.761,四项指标联合检测时所得AUC为0.865,高于各项指标单独检测所得值。结论超声造影定量参数、CRP/Alb与CAS患者发生IS有关,联合检测对IS的发生具有一定预测价值,值得临床上推广应用。 展开更多
关键词 超声造影定量参数 C反应蛋白/白蛋白比率 颈动脉粥样硬化 缺血性脑卒中 预测
暂未订购
动态对比增强磁共振成像技术在前列腺癌临床诊断中的价值研究
15
作者 蒋大海 陈兰 《中国医疗器械信息》 2026年第3期82-84,共3页
目的:分析动态对比增强磁共振成像(DCE-MRI)在前列腺癌临床诊断中的应用价值。方法:选取2023年9月~2024年12月于潜江市中心医院进行诊断与治疗的疑似前列腺癌患者103例,所有患者均接受MRI常规扫描及DCE-MRI,以病理诊断结果为金标准,分... 目的:分析动态对比增强磁共振成像(DCE-MRI)在前列腺癌临床诊断中的应用价值。方法:选取2023年9月~2024年12月于潜江市中心医院进行诊断与治疗的疑似前列腺癌患者103例,所有患者均接受MRI常规扫描及DCE-MRI,以病理诊断结果为金标准,分析并比较两种检查方法对前列腺癌的诊断效能,比较前列腺癌与良性前列腺疾病患者的DCE-MRI定量参数及相关检查指标。结果:经病理检查,共检出前列腺癌(阳性)患者67例,良性前列腺疾病(阴性)患者36例。DCE-MRI的准确度、灵敏度、特异度、阳性预测值、阴性预测值均高于MRI常规扫描(P<0.05)。前列腺癌患者速率常数(K_(ep))、容积转运常数(K^(trans))值均低于良性前列腺疾病患者(P<0.05);不同疾病类型患者血管外细胞外间隙体积百分数(V_(e))比较,差异无统计学意义(P>0.05)。前列腺癌患者动态扫描起始值低于良性前列腺疾病患者,最大信号强度、最大信号强度值均高于良性前列腺疾病患者(P<0.05)。结论:DCE-MRI在前列腺癌临床诊断中的应用价值较高,临床可通过多种参数对前列腺疾病进行定性和定量分析。 展开更多
关键词 前列腺癌 动态对比增强磁共振成像 磁共振常规扫描 定量参数 诊断效能
暂未订购
CT征象联合定量参数预测肺结节良恶性
16
作者 韩妞妞 李猛 +3 位作者 王腾飞 苏相茹 吴嘉倩 陈亚明 《中国医学计算机成像杂志》 北大核心 2026年第1期25-32,共8页
目的:探讨胸部CT征象联合定量参数分析预测肺结节良恶性的价值。方法:回顾性纳入2020年1月1日一2024年9月30日肺结节患者共计504例(恶性395例,良性109例),按7:3的比例随机将其分为训练集和测试集。所有肺结节的CT征象及定量参数均通过... 目的:探讨胸部CT征象联合定量参数分析预测肺结节良恶性的价值。方法:回顾性纳入2020年1月1日一2024年9月30日肺结节患者共计504例(恶性395例,良性109例),按7:3的比例随机将其分为训练集和测试集。所有肺结节的CT征象及定量参数均通过人工智能(AI)软件(联影智能)检出,且所有肺结节CT值范围均为-300~50HU。对肺结节的定量参数进行统计学分析,通过logistic回归分析评估定量参数对良恶性肺结节的诊断效能。采用5折交叉验证,利用最小绝对收缩与选择算子(LASSO)在训练集上进行特征选择,并基于筛选的特征构建极端梯度提升(XGBoost)模型。使用受试者工作特征曲线(ROC)计算曲线下面积(AUC)、灵敏度、特异度、准确度、精确度和Flscore评估该模型的预测性能。结果:肺结节CT征象中分叶征、毛刺征、充气支气管征、棘突征差异有统计学意义(P<0.05)。Logistic回归分析显示偏度是鉴别良恶性肺结节的独立预测因子,质量占比<-300HU/mg对肺结节良恶性的鉴别诊断效能最高。经特征筛选出质量占比<-300HU/mg、最小CT值、平均CT值三个参数建立XGBoost模型,该模型最终5折的平均结果训练集的AUC、灵敏度、特异度、准确度、精确度和F1score分别为0.966、0.996、0.597、0.910、0.899和0.945;测试集的AUC、灵敏度、特异度、准确度、精确度和F1score分别为0.789、0.941、0.344、0.813、0.841和0.888。测试集和训练集的AUC值均较高,表明该模型具有较好的预测性能。同时,该模型在识别恶性肺结节方面表现出极高的灵敏度,能最大限度地降低漏诊风险。由于测试集的特异度较低,会将部分良性肺结节误判为恶性。因此,该模型非常适合作为临床辅助筛查工具用于高效排除低风险结节,并对高风险结节进行预警,由医生最终甄别并确定随访或治疗方案。结论:分叶征、毛刺征、充气支气管征、棘突征、偏度及质量占比<-300HU/mg提示肺结节恶性可能大,且CT征象与定量参数联合建立的XGBoost模型有助于更准确鉴别肺结节的良恶性。 展开更多
关键词 CT征象 良性肺结节 恶性肺结节 定量参数 预测模型
暂未订购
超声造影定量参数对肝细胞肝癌的诊断价值及其与肿瘤血管生成的相关性
17
作者 韩思维 朱巧英 +1 位作者 周锋盛 张静 《影像研究与医学应用》 2026年第1期20-22,26,共4页
目的:探讨超声造影(CEUS)定量参数对肝细胞肝癌的诊断价值及其与肿瘤血管生成的相关性。方法:收集2022年5月—2025年5月于无锡市人民医院经病理组织学检查确诊的86例肝细胞肝癌患者(肝细胞肝癌组)和50例肝脏良性病变患者(对照组)为研究... 目的:探讨超声造影(CEUS)定量参数对肝细胞肝癌的诊断价值及其与肿瘤血管生成的相关性。方法:收集2022年5月—2025年5月于无锡市人民医院经病理组织学检查确诊的86例肝细胞肝癌患者(肝细胞肝癌组)和50例肝脏良性病变患者(对照组)为研究对象。患者均行CEUS检查,采用免疫组织化学染色法检测微血管密度(MVD)。比较两组的CEUS参数[达峰时间(TTP)、平均渡越时间(MTT)、上升时间(RT)、峰值强度(IMAX)]及MVD计数,绘制受试者工作特征(ROC)曲线分析CEUS定量参数对肝细胞肝癌的诊断价值,并采用Pearson相关性分析CEUS定量参数与肝细胞肝癌患者MVD计数的相关性。结果:肝细胞肝癌组TTP、MTT、RT均短于对照组,IMAX高于对照组(P<0.05)。肝细胞肝癌组MVD计数高于对照组(P<0.05)。ROC曲线显示,CEUS定量参数RT、TTP、MTT及IMAX诊断肝细胞肝癌的曲线下面积分别为0.843、0.765、0.805、0.842,灵敏度为74.0%、74.0%、70.0%、74.0%,特异度为83.7%、72.1%、80.2%、83.7%。Pearson相关性分析显示,CEUS定量参数TTP、MTT、RT与MVD计数均呈负相关(r=-0.758、-0.660、-0.721,P<0.05),IMAX与MVD计数呈正相关(r=0.745,P<0.05)。结论:CEUS定量参数TTP、MTT、RT、IMAX对肝细胞肝癌均具有一定的诊断价值,且与肿瘤血管生成存在相关性,可作为肝细胞肝癌辅助诊疗的有效方法。 展开更多
关键词 肝细胞肝癌 超声造影 超声定量参数 微血管密度 相关性
暂未订购
能谱CT定量参数评估症状性颈动脉斑块患者卒中复发风险的价值
18
作者 倪俊 陶磊 叶亮 《中国CT和MRI杂志》 2026年第2期28-31,共4页
目的分析能谱CT定量参数评估症状性颈动脉斑块患者卒中复发风险的价值。方法选择106例于2024年1月至2025年9月在我院治疗后复查的脑梗患者的临床资料展开回顾性分析,依据90 d后CTA复查结果分为复发组(n=28)、未复发组(n=78)。比较两组... 目的分析能谱CT定量参数评估症状性颈动脉斑块患者卒中复发风险的价值。方法选择106例于2024年1月至2025年9月在我院治疗后复查的脑梗患者的临床资料展开回顾性分析,依据90 d后CTA复查结果分为复发组(n=28)、未复发组(n=78)。比较两组基线资料、能谱CT定量参数,通过多因素Logistic回归分析症状性颈动脉斑块患者卒中复发的影响因素。采用ROC分析能谱CT定量参数评估症状性颈动脉斑块患者卒中复发风险的价值。结果复发组碘浓度(IC)、脂质核心百分比高于未复发组,λ_(HU)、纤维组织百分比低于未复发组(P<0.05);多因素Logistic回归分析证实,IC、λ_(HU)、脂质核心百分比、纤维组织百分比是症状性颈动脉斑块患者卒中复发的影响因素,均有P<0.05;ROC分析证实,IC、λ_(HU)、脂质核心百分比、纤维组织百分比可用于评估症状性颈动脉斑块患者卒中复发风险,曲线下面积分别为0.766、0.789、0.811、0.826,联合评估可获得更高曲线下面积0.931,均有P<0.05。结论能谱CT定量参数中IC、λ_(HU)、脂质核心百分比、纤维组织百分比是评估症状性颈动脉斑块患者卒中复发风险的独立因素,临床诊治时可结合以上因素进一步筛查复发高危患者,及时采取防治措施。 展开更多
关键词 能谱CT定量参数 症状性颈动脉斑块 缺血性卒中 复发 脂质核心百分比
暂未订购
术前CT肺密度联合血清NSE、CEA检测对肺癌患者术后肺部并发症的预测价值
19
作者 孟轲 王亚洲 +3 位作者 窦允龙 杨富阁 程国飞 黄方方 《分子诊断与治疗杂志》 2026年第1期218-221,共4页
目的探讨术前胸部CT肺密度定量参数联合血清神经元特异性烯醇化酶(NSE)和癌胚抗原(CEA)水平对肺癌患者术后肺部并发症(PPCs)的预测价值。方法回顾性纳入2022年3月至2024年3月于河南中医药大学第一附属医院接受根治性肺切除术的非小细胞... 目的探讨术前胸部CT肺密度定量参数联合血清神经元特异性烯醇化酶(NSE)和癌胚抗原(CEA)水平对肺癌患者术后肺部并发症(PPCs)的预测价值。方法回顾性纳入2022年3月至2024年3月于河南中医药大学第一附属医院接受根治性肺切除术的非小细胞肺癌(NSCLC)患者147例,依据术后30 d内患者是否发生PPCs分为PPCs组(n=62例)与非PPCs组(n=85)。比较两组CT肺密度参数及血清NSE、CEA水平差异,通过Logistic回归分析确定PPCs的独立危险因素,并构建联合预测模型,利用ROC评估单一指标及联合模型对PPCs的预测效能。结果PPCs组与非PPCs组在年龄、吸烟史、肿瘤直径方面比较差异有统计学意义(P<0.05)。PPCs组LAA%、血清NSE和CEA水平均显著高于非PPCs组,MLD显著低于对照组,差异有统计学意义(P<0.05)。多因素Logistic回归分析显示,LAA%升高、血清NSE降低和CEA升高是PPCs的独立危险因素。ROC曲线分析表明,联合模型(LAA%+NSE+CEA)的预测效能最优,AUC为0.870(95%CI:0.815~0.926),显著高于单一指标(P<0.05)。结论术前CT肺密度、血清NSE及CEA水平与肺癌患者术后肺部并发症的发生密切相关,三者联合检测可显著提高对术后肺部并发症的预测准确性。 展开更多
关键词 肺密度定量参数 肺癌 并发症 根治性肺切除术
暂未订购
多普勒超声定量参数与性激素预测羊水过少妊娠结局
20
作者 林晓 张婧茹 朱俊 《广州医科大学学报》 2026年第1期34-38,共5页
目的:探讨多普勒超声定量参数联合性激素检测对羊水过少孕妇妊娠结局的预测价值。方法:选取2022年2月至2024年2月间本院收治的羊水过少妊娠产妇188例为研究对象。统计并根据妊娠结局,将观察组进一步分为妊娠不良组和妊娠良好组。检测对... 目的:探讨多普勒超声定量参数联合性激素检测对羊水过少孕妇妊娠结局的预测价值。方法:选取2022年2月至2024年2月间本院收治的羊水过少妊娠产妇188例为研究对象。统计并根据妊娠结局,将观察组进一步分为妊娠不良组和妊娠良好组。检测对比两组多普勒超声定量参数和性激素水平。采用ROC曲线分析多普勒超声定量参数和性激素水平对不良妊娠结局的预测价值。结果:188例羊水过少妊娠产妇中,发生妊娠不良产妇有71例,不良妊娠发生率为37.77%。未发生不良妊娠产妇有117例。妊娠不良组中肾动脉(RA)、脐动脉(UA)阻力指数高于妊娠良好组,大脑中动脉(MCA)阻力指数以及卵泡刺激素(FSH)、雌二醇、孕酮、垂体泌乳素水平低于妊娠良好组(P<0.05)。ROC曲线显示,所有参数联合预测产妇妊娠不良的AUC为0.922,高于多普勒超声参数联合预测及激素四项水平联合预测(AUC分别为0.834、0.865)。结论:羊水过少产妇RA MCA UA阻力指数联合激素六项中FSH、雌二醇、孕酮、垂体泌乳素水平对其妊娠结局具有较高预测价值。 展开更多
关键词 多普勒超声 定量参数 性激素水平 羊水过少 妊娠结局
暂未订购
上一页 1 2 57 下一页 到第
使用帮助 返回顶部