目的探讨声脉冲辐射力(acoustic radiation force impulse,ARFI)弹性成像联合常规超声鉴别乳腺良恶性肿物的价值。方法选取2014年1月至2020年6月就诊于中日友好医院并经病理证实的乳腺肿物患者360例,共360个肿物,术前行常规超声及ARFI成...目的探讨声脉冲辐射力(acoustic radiation force impulse,ARFI)弹性成像联合常规超声鉴别乳腺良恶性肿物的价值。方法选取2014年1月至2020年6月就诊于中日友好医院并经病理证实的乳腺肿物患者360例,共360个肿物,术前行常规超声及ARFI成像,获得剪切波速度(shear wave velocity,SWV)值。所有肿物行乳腺影像报告与数据系统(breast imaging reporting and data system,BI-RADS)分类,并绘制SWV值的ROC曲线。VTQ界值取约登指数最大时ROC曲线的值4.05 m/s,BI-RADS及联合法界值均为3~4A类,计算3种方法的AUC、敏感性、特异性、准确性、阳性预测值及阴性预测值,比较三者对乳腺肿物的诊断效能。结果乳腺恶性肿物227个,良性133个,恶性肿物SWV值高于良性,差异有统计学意义[(6.08±2.95)m/s比(3.16±2.14)m/s,P=0.000]。常规超声、ARFI及联合法AUC分别为0.742、0.748、0.833,敏感性为98.7%、66.1%、90.7%,特异性为49.6%、83.5%、75.9%,准确性为80.6%、72.5%、85.3%,阳性预测值为77.0%、87.2%、86.6%,阴性预测值为95.7%、59.0%及82.8%。联合法将86.3%的病理良性4A类肿物降为3类。结论ARFI辅助常规超声能够提高乳腺肿物诊断效能,诊断特异性提高26.3%,能够避免86.3%的病理良性4A类肿物穿刺活检。展开更多
背景与目的:儿童及青少年甲状腺癌发病率逐年升高,且有较高的转移率及复发率。如果对儿童应用基于成人特点建立的甲状腺结节诊断标准则往往具有较高的漏诊率、误诊率和不必要活检率,本研究旨在建立儿童及青少年甲状腺结节的声像图分级...背景与目的:儿童及青少年甲状腺癌发病率逐年升高,且有较高的转移率及复发率。如果对儿童应用基于成人特点建立的甲状腺结节诊断标准则往往具有较高的漏诊率、误诊率和不必要活检率,本研究旨在建立儿童及青少年甲状腺结节的声像图分级诊断模型,对比其与美国放射学会(American College of Radiology,ACR)甲状腺影像报告与数据系统(Thyroid Imaging-Reporting and Data System,TI-RADS)的诊断效能。方法:纳入2000年1月—2017年10月中国医学科学院北京协和医学院北京协和医院收治的144例0~18岁的甲状腺结节患者作为训练集,2015年11月—2022年1月中日友好医院和民航总医院收治的41例0~18岁的甲状腺结节患者作为测试集,以病理学诊断作为金标准,将差异有统计学意义的超声特征进行多因素二元logistic回归分析,建立超声分级诊断模型并将模型带入测试集,比较其与ACR TI-RADS的诊断效能。结果:训练集中实性、低回声、纵横比≥1、边缘不规则及微钙化等差异均有统计学意义(P<0.05)。Logistic回归分析显示,低回声、实性、边缘不规则及有钙化是诊断儿童及青少年甲状腺癌的独立预测因子。以上述独立预测因子建立超声分级系统,测试集中此分级模型与ACR TI-RADS相比具有更高的诊断准确率(92.7%vs 82.9%)。结论:以实性、低回声、边缘不规则及微钙化建立的分级诊断模型可用于儿童及青少年甲状腺结节的诊断,与ACR TI-RADS相比,具有更高的诊断准确率。展开更多
Heavy commercial vehicles equipped with a hydraulic hub-motor auxiliary system(HHMAS)often operate under complex road conditions.Selecting appropriate operating mode and realizing reasonable energy management to match...Heavy commercial vehicles equipped with a hydraulic hub-motor auxiliary system(HHMAS)often operate under complex road conditions.Selecting appropriate operating mode and realizing reasonable energy management to match unpredictable road conditions are the keys to the driving performance and fuel economy of HHMAS.Therefore,a multi-mode energy management strategy(MM-EMS)based on improved global optimization algorithm is proposed in this study for HHMAS.First,an improved dynamic programming(DP)algorithm for HHMAS is developed.This improved DP algorithm considers the effect of SOC and vehicle speed,thereby preventing the calculation results from falling into local optimization.This algorithm also reduces the dimension of the control variable data grid,and the calculation time is reduced by 35%without affecting the accuracy.Second,a MM-EMS with hierarchical control is proposed.This strategy extracts the optimal control rules from the results of the improved DP algorithm.Then it divides the system’s operating region into two types,namely,single-mode working region and mixedmode working region.In the single-mode working region,mode switching is realized through fixed thresholds.In the mixedmode working region,a linear quadratic regulator(LQR)is adopted to determine a target mode and realize SOC tracking control.Finally,the designed MM-EMS is verified separately in offline simulation and hardware-in-the-loop(HIL)under actual vehicle test cycles.Simulation results show that the results between HIL and offline simulation are largely coincidence.Besides,in comparison with the engine optimal control strategy,the designed MM-EMS can achieve an approximate optimal control,with oil savings of 3.96%.展开更多
文摘目的探讨声脉冲辐射力(acoustic radiation force impulse,ARFI)弹性成像联合常规超声鉴别乳腺良恶性肿物的价值。方法选取2014年1月至2020年6月就诊于中日友好医院并经病理证实的乳腺肿物患者360例,共360个肿物,术前行常规超声及ARFI成像,获得剪切波速度(shear wave velocity,SWV)值。所有肿物行乳腺影像报告与数据系统(breast imaging reporting and data system,BI-RADS)分类,并绘制SWV值的ROC曲线。VTQ界值取约登指数最大时ROC曲线的值4.05 m/s,BI-RADS及联合法界值均为3~4A类,计算3种方法的AUC、敏感性、特异性、准确性、阳性预测值及阴性预测值,比较三者对乳腺肿物的诊断效能。结果乳腺恶性肿物227个,良性133个,恶性肿物SWV值高于良性,差异有统计学意义[(6.08±2.95)m/s比(3.16±2.14)m/s,P=0.000]。常规超声、ARFI及联合法AUC分别为0.742、0.748、0.833,敏感性为98.7%、66.1%、90.7%,特异性为49.6%、83.5%、75.9%,准确性为80.6%、72.5%、85.3%,阳性预测值为77.0%、87.2%、86.6%,阴性预测值为95.7%、59.0%及82.8%。联合法将86.3%的病理良性4A类肿物降为3类。结论ARFI辅助常规超声能够提高乳腺肿物诊断效能,诊断特异性提高26.3%,能够避免86.3%的病理良性4A类肿物穿刺活检。
文摘背景与目的:儿童及青少年甲状腺癌发病率逐年升高,且有较高的转移率及复发率。如果对儿童应用基于成人特点建立的甲状腺结节诊断标准则往往具有较高的漏诊率、误诊率和不必要活检率,本研究旨在建立儿童及青少年甲状腺结节的声像图分级诊断模型,对比其与美国放射学会(American College of Radiology,ACR)甲状腺影像报告与数据系统(Thyroid Imaging-Reporting and Data System,TI-RADS)的诊断效能。方法:纳入2000年1月—2017年10月中国医学科学院北京协和医学院北京协和医院收治的144例0~18岁的甲状腺结节患者作为训练集,2015年11月—2022年1月中日友好医院和民航总医院收治的41例0~18岁的甲状腺结节患者作为测试集,以病理学诊断作为金标准,将差异有统计学意义的超声特征进行多因素二元logistic回归分析,建立超声分级诊断模型并将模型带入测试集,比较其与ACR TI-RADS的诊断效能。结果:训练集中实性、低回声、纵横比≥1、边缘不规则及微钙化等差异均有统计学意义(P<0.05)。Logistic回归分析显示,低回声、实性、边缘不规则及有钙化是诊断儿童及青少年甲状腺癌的独立预测因子。以上述独立预测因子建立超声分级系统,测试集中此分级模型与ACR TI-RADS相比具有更高的诊断准确率(92.7%vs 82.9%)。结论:以实性、低回声、边缘不规则及微钙化建立的分级诊断模型可用于儿童及青少年甲状腺结节的诊断,与ACR TI-RADS相比,具有更高的诊断准确率。
基金the National Key Research and Development Program of China (Grant No. 2018YFB0105900)。
文摘Heavy commercial vehicles equipped with a hydraulic hub-motor auxiliary system(HHMAS)often operate under complex road conditions.Selecting appropriate operating mode and realizing reasonable energy management to match unpredictable road conditions are the keys to the driving performance and fuel economy of HHMAS.Therefore,a multi-mode energy management strategy(MM-EMS)based on improved global optimization algorithm is proposed in this study for HHMAS.First,an improved dynamic programming(DP)algorithm for HHMAS is developed.This improved DP algorithm considers the effect of SOC and vehicle speed,thereby preventing the calculation results from falling into local optimization.This algorithm also reduces the dimension of the control variable data grid,and the calculation time is reduced by 35%without affecting the accuracy.Second,a MM-EMS with hierarchical control is proposed.This strategy extracts the optimal control rules from the results of the improved DP algorithm.Then it divides the system’s operating region into two types,namely,single-mode working region and mixedmode working region.In the single-mode working region,mode switching is realized through fixed thresholds.In the mixedmode working region,a linear quadratic regulator(LQR)is adopted to determine a target mode and realize SOC tracking control.Finally,the designed MM-EMS is verified separately in offline simulation and hardware-in-the-loop(HIL)under actual vehicle test cycles.Simulation results show that the results between HIL and offline simulation are largely coincidence.Besides,in comparison with the engine optimal control strategy,the designed MM-EMS can achieve an approximate optimal control,with oil savings of 3.96%.
