BACKGROUND Colon cancer(CC)is one of the most common cancers of the digestive tract,the third most common cancer worldwide,and the second most common cause of cancer-related deaths.Previous studies have demonstrated a...BACKGROUND Colon cancer(CC)is one of the most common cancers of the digestive tract,the third most common cancer worldwide,and the second most common cause of cancer-related deaths.Previous studies have demonstrated a higher risk of lymph node metastasis(LNM)in young patients with CC.It might be reasonable to treat patients with early-onset locally advanced CC with extended lymph node dissection.However,few studies have focused on early-onset CC(ECC)patients with LNM.At present,the methods of predicting and evaluating the prognosis of ECC patients with LNM are controversial.From the data of patients with CC obtained from the Surveillance,Epidemiology,and End Results(SEER)database,data of young patients with ECC(≤50 years old)was screened.Patients with unknown data were excluded from the study,while the remaining patients were included.The patients were randomly divided into a training group(train)and a testing group(test)in the ratio of 7:3,while building the model.The model was constructed by the training group and verified by the testing group.Using multiple Cox regression models to compare the prediction efficiency of LNM indicators,nomograms were built based on the best model selected for overall survival(OS)and cause-specific survival(CSS).In the two groups,the performance of the nomogram was evaluated by constructing a calibration plot,time-dependent area under the curve(AUC),and decision curve analysis.Finally,the patients were grouped based on the risk score predicted by the prognosis model,and the survival curve was constructed after comparing the survival status of the high and low-risk groups.RESULTS Records of 26922 ECC patients were screened from the SEER database.N classification,positive lymph nodes(PLN),lymph node ratio(LNR)and log odds of PLN(LODDS)were considered to be independent predictors of OS and CSS.In addition,independent risk factors for OS included gender,race,marital status,primary site,histology,grade,T,and M classification,while the independent prognostic factors for CSS included r展开更多
针对自然条件下原木端面图像的分割问题,结合原木端面图像的特点,改进传统CV(Chan and Vese)模型,对演化曲线内部使用梯度进行拟合,同时融入局部图像拟合LIF(Local Image Fitting)模型,加入圆形先验知识,提出了基于圆形约束的改进活动...针对自然条件下原木端面图像的分割问题,结合原木端面图像的特点,改进传统CV(Chan and Vese)模型,对演化曲线内部使用梯度进行拟合,同时融入局部图像拟合LIF(Local Image Fitting)模型,加入圆形先验知识,提出了基于圆形约束的改进活动轮廓模型CV-LIF,将全局能量和局部能量结合到一起,共同约束轮廓线的演化。在对图像进行预分割的基础上,利用多水平集表示待分割区域,运用基于圆形约束的改进活动轮廓模型对每个水平集区域进行再分割,解决了复杂背景下多个原木端面分割不准确的问题。通过实验,分别对单个及多个原木端面图像进行分割,结果表明该方法可以较好地分割出图像中的原木端面,而且具有较好的抗噪性能,实现速度较快。展开更多
文摘BACKGROUND Colon cancer(CC)is one of the most common cancers of the digestive tract,the third most common cancer worldwide,and the second most common cause of cancer-related deaths.Previous studies have demonstrated a higher risk of lymph node metastasis(LNM)in young patients with CC.It might be reasonable to treat patients with early-onset locally advanced CC with extended lymph node dissection.However,few studies have focused on early-onset CC(ECC)patients with LNM.At present,the methods of predicting and evaluating the prognosis of ECC patients with LNM are controversial.From the data of patients with CC obtained from the Surveillance,Epidemiology,and End Results(SEER)database,data of young patients with ECC(≤50 years old)was screened.Patients with unknown data were excluded from the study,while the remaining patients were included.The patients were randomly divided into a training group(train)and a testing group(test)in the ratio of 7:3,while building the model.The model was constructed by the training group and verified by the testing group.Using multiple Cox regression models to compare the prediction efficiency of LNM indicators,nomograms were built based on the best model selected for overall survival(OS)and cause-specific survival(CSS).In the two groups,the performance of the nomogram was evaluated by constructing a calibration plot,time-dependent area under the curve(AUC),and decision curve analysis.Finally,the patients were grouped based on the risk score predicted by the prognosis model,and the survival curve was constructed after comparing the survival status of the high and low-risk groups.RESULTS Records of 26922 ECC patients were screened from the SEER database.N classification,positive lymph nodes(PLN),lymph node ratio(LNR)and log odds of PLN(LODDS)were considered to be independent predictors of OS and CSS.In addition,independent risk factors for OS included gender,race,marital status,primary site,histology,grade,T,and M classification,while the independent prognostic factors for CSS included r
文摘针对自然条件下原木端面图像的分割问题,结合原木端面图像的特点,改进传统CV(Chan and Vese)模型,对演化曲线内部使用梯度进行拟合,同时融入局部图像拟合LIF(Local Image Fitting)模型,加入圆形先验知识,提出了基于圆形约束的改进活动轮廓模型CV-LIF,将全局能量和局部能量结合到一起,共同约束轮廓线的演化。在对图像进行预分割的基础上,利用多水平集表示待分割区域,运用基于圆形约束的改进活动轮廓模型对每个水平集区域进行再分割,解决了复杂背景下多个原木端面分割不准确的问题。通过实验,分别对单个及多个原木端面图像进行分割,结果表明该方法可以较好地分割出图像中的原木端面,而且具有较好的抗噪性能,实现速度较快。
