The presence of lymph node metastasis is an important prognostic factor for patients with esophageal cancer.Accurate assessment of lymph nodes in thoracic esophageal carcinoma is essential for selecting appropriate tr...The presence of lymph node metastasis is an important prognostic factor for patients with esophageal cancer.Accurate assessment of lymph nodes in thoracic esophageal carcinoma is essential for selecting appropriate treatment and forecasting disease progression.Positron emission tomography combined with computed tomography(PET/CT)is becoming an important tool in the workup of esophageal carcinoma.Here,we evaluated the effectiveness of the maximum standardized uptake value(SUVmax)in assessing lymph node metastasis in esophageal squamous cell carcinoma(ESCC)prior to surgery.Fifty-nine surgical patients with pathologically confirmed thoracic ESCC were retrospectively studied.These patients underwent radical esophagectomy with pathologic evaluation of lymph nodes.They all had18F-FDG PET/CT scans in their preoperative staging procedures.None had a prior history of cancer.The pathologic status and PET/CT SUVmax of lymph nodes were collected to calculate the receiver operating characteristic(ROC)curve and to determine the best cutoff value of the PET/CT SUVmax to distinguish benign from malignant lymph nodes.Lymph node data from 27 others were used for the validation.A total of 323 lymph nodes including 39 metastatic lymph nodes were evaluated in the training cohort,and 117lymph nodes including 32 metastatic lymph nodes were evaluated in the validation cohort.The cutoff point of the SUVmax for lymph nodes was 4.1,as calculated by ROC curve(sensitivity,80%;specificity,92%;accuracy,90%).When this cutoff value was applied to the validation cohort,a sensitivity,a specificity,and an accuracy of 81%,88%,and 86%,respectively,were obtained.These results suggest that the SUVmax of lymph nodes predicts malignancy.Indeed,when an SUVmax of 4.1 was used instead of 2.5,FDG-PET/CT was more accurate in assessing nodal metastasis.展开更多
This paper discusses how the positive and negative predictive values vary withcontrary variations of sensitivity and specificity at a certain disease prevalence.Let thesensitiviy be Se and the specificity be Sp at the...This paper discusses how the positive and negative predictive values vary withcontrary variations of sensitivity and specificity at a certain disease prevalence.Let thesensitiviy be Se and the specificity be Sp at the initial cutoff point,correspondingly Se’and Sp’ at a new cutoff point:A=Se’/Se:B-(1-Sp’)/(1-Sp):C=Sp’/Sp;D=(I-Se’)/(I-Se).Moving the cutoff point from the initial point to the new point,if the contrary variationsof the sensitivity and specificity satisfy the inequality A】B,then the positive predictivevalue increases,otherwise it decreases or remains unchanged.If the variations satisfy theinequality C】D,then the negative prcdictive value increases,otherwise it decreasses or re-mains unchanged.展开更多
Background:Bronchial hyperresponsiveness (BHR) is a fundamental pathophysiological characteristic of asthma.Although several factors such as airway caliber can affect BHR,no study has established age-dependent cutoff ...Background:Bronchial hyperresponsiveness (BHR) is a fundamental pathophysiological characteristic of asthma.Although several factors such as airway caliber can affect BHR,no study has established age-dependent cutoff values of BHR to methacholine for the diagnosis of asthma in children.We investigated the cutoff values of the methacholine challenge test (MCT) in the diagnosis of asthma according to age.Methods:A total of 2383 individuals aged from 6 to 15 years old were included in this study.MCTs using the five-breath technique were performed in 350 children with suspected asthma based on symptoms by pediatric allergists and in 2033 healthy children from a general population-based cohort.We determined the provocative concentration of methacholine producing a 20% decrease in forced expiratory volume in 1 second from baseline (PC20).A modified Korean version of the International Study of Asthma and Allergies in Childhood questionnaire was used to distinguish asthmatics and healthy subjects.Receiveroperator characteristic curve analysis was used to assess the cutoff value of PC20 for the diagnosis of asthma.Results:Cutoff values of methacholine PC20,which provided the best combination of diagnostic sensitivity and specificity,showed an increasing pattern with age:5.8,9.1,11.8,12.6,14.9,21.7,23.3,21.1,21.1,and 24.6 mg/mL at ages 6,7,8,9,10,11,12,13,14,and 15 years,respectively.Conclusion:The application of different cutoff values of methacholine PC20 depending on age might be a practical modification for the diagnosis of asthma in children and adolescents with asthmatic symptoms.展开更多
文摘The presence of lymph node metastasis is an important prognostic factor for patients with esophageal cancer.Accurate assessment of lymph nodes in thoracic esophageal carcinoma is essential for selecting appropriate treatment and forecasting disease progression.Positron emission tomography combined with computed tomography(PET/CT)is becoming an important tool in the workup of esophageal carcinoma.Here,we evaluated the effectiveness of the maximum standardized uptake value(SUVmax)in assessing lymph node metastasis in esophageal squamous cell carcinoma(ESCC)prior to surgery.Fifty-nine surgical patients with pathologically confirmed thoracic ESCC were retrospectively studied.These patients underwent radical esophagectomy with pathologic evaluation of lymph nodes.They all had18F-FDG PET/CT scans in their preoperative staging procedures.None had a prior history of cancer.The pathologic status and PET/CT SUVmax of lymph nodes were collected to calculate the receiver operating characteristic(ROC)curve and to determine the best cutoff value of the PET/CT SUVmax to distinguish benign from malignant lymph nodes.Lymph node data from 27 others were used for the validation.A total of 323 lymph nodes including 39 metastatic lymph nodes were evaluated in the training cohort,and 117lymph nodes including 32 metastatic lymph nodes were evaluated in the validation cohort.The cutoff point of the SUVmax for lymph nodes was 4.1,as calculated by ROC curve(sensitivity,80%;specificity,92%;accuracy,90%).When this cutoff value was applied to the validation cohort,a sensitivity,a specificity,and an accuracy of 81%,88%,and 86%,respectively,were obtained.These results suggest that the SUVmax of lymph nodes predicts malignancy.Indeed,when an SUVmax of 4.1 was used instead of 2.5,FDG-PET/CT was more accurate in assessing nodal metastasis.
文摘This paper discusses how the positive and negative predictive values vary withcontrary variations of sensitivity and specificity at a certain disease prevalence.Let thesensitiviy be Se and the specificity be Sp at the initial cutoff point,correspondingly Se’and Sp’ at a new cutoff point:A=Se’/Se:B-(1-Sp’)/(1-Sp):C=Sp’/Sp;D=(I-Se’)/(I-Se).Moving the cutoff point from the initial point to the new point,if the contrary variationsof the sensitivity and specificity satisfy the inequality A】B,then the positive predictivevalue increases,otherwise it decreases or remains unchanged.If the variations satisfy theinequality C】D,then the negative prcdictive value increases,otherwise it decreasses or re-mains unchanged.
文摘Background:Bronchial hyperresponsiveness (BHR) is a fundamental pathophysiological characteristic of asthma.Although several factors such as airway caliber can affect BHR,no study has established age-dependent cutoff values of BHR to methacholine for the diagnosis of asthma in children.We investigated the cutoff values of the methacholine challenge test (MCT) in the diagnosis of asthma according to age.Methods:A total of 2383 individuals aged from 6 to 15 years old were included in this study.MCTs using the five-breath technique were performed in 350 children with suspected asthma based on symptoms by pediatric allergists and in 2033 healthy children from a general population-based cohort.We determined the provocative concentration of methacholine producing a 20% decrease in forced expiratory volume in 1 second from baseline (PC20).A modified Korean version of the International Study of Asthma and Allergies in Childhood questionnaire was used to distinguish asthmatics and healthy subjects.Receiveroperator characteristic curve analysis was used to assess the cutoff value of PC20 for the diagnosis of asthma.Results:Cutoff values of methacholine PC20,which provided the best combination of diagnostic sensitivity and specificity,showed an increasing pattern with age:5.8,9.1,11.8,12.6,14.9,21.7,23.3,21.1,21.1,and 24.6 mg/mL at ages 6,7,8,9,10,11,12,13,14,and 15 years,respectively.Conclusion:The application of different cutoff values of methacholine PC20 depending on age might be a practical modification for the diagnosis of asthma in children and adolescents with asthmatic symptoms.
