AIM:To identify whether there could have been changes in survival if lymph node ratio (N ratio) had been used.METHODS:We assessed 334 gastric adenocarcinoma cases retrospectively between 2001 and 2009.Two hundred and ...AIM:To identify whether there could have been changes in survival if lymph node ratio (N ratio) had been used.METHODS:We assessed 334 gastric adenocarcinoma cases retrospectively between 2001 and 2009.Two hundred and sixteen patients out of 334 were included in the study.Patients were grouped according to disection1 (D1) or dissection 2 (D2) dissection.We compared the estimated survival and actual survival determined by Pathologic nodes (pN) class and N ratio,and SPSS 15.0 software was used for statistical analysis.RESULTS:Ninety-six (44.4%) patients underwent D1 dissection and 120 (55.6%) had D2 dissection.When groups were evaluated,23 (24.0%) patients in D1 and 21 (17.5%) in D2 had stage migration (P=0.001).When both D1 and D2 groups were evaluated for number of pathological lymph nodes,despite the fact that there was no difference in N ratio between D1 and D2 groups,a statistically significant difference was found between them with regard to pN1 and pN2 groups (P=0.047,P=0.044 respectively).In D1,pN0 had the longest survival while pN3 had the shortest.In D2,pN0 had the longest survival whereas pN3 had the shortest survival.CONCLUSION:N ratio is an accurate staging system for defining prognosis and treatment plan,thus decreasing methodological errors in gastric cancer staging.展开更多
Land cover change detection is the major goal in multitemporal remote sensing studies. It is well known that remotely-sensed images of the same area acquired on different dates tend to be affected by radiometric diffe...Land cover change detection is the major goal in multitemporal remote sensing studies. It is well known that remotely-sensed images of the same area acquired on different dates tend to be affected by radiometric differences and registration problems. These influences are considered as noise in the process and may induce the user to both： signalling false changes and masking real surface changes. The difference image produced by subtracting two co-registered images is a standard initial step in change detection algorithms. This image naturally appears to be noisier than the original ones and has at least two populations： （1） the noise-like and （2） the real changes. The problem that arises is how to discriminate them. There are several approaches to perform change detection reported in the literature and some studies have employed synthetic images. By using synthetic images, the accuracy assessment of specific algorithm can be done more accurately. The question at this point is： what is the acceptable noise level to be added on the synthetic images to simulate a real problem？ This paper attempts to answer this question by suggesting values of SNR （signal-to-noise ratio） obtained from experiments performed on TM-Landsat-5 and CCD-CBERS-2B images.展开更多
文摘AIM:To identify whether there could have been changes in survival if lymph node ratio (N ratio) had been used.METHODS:We assessed 334 gastric adenocarcinoma cases retrospectively between 2001 and 2009.Two hundred and sixteen patients out of 334 were included in the study.Patients were grouped according to disection1 (D1) or dissection 2 (D2) dissection.We compared the estimated survival and actual survival determined by Pathologic nodes (pN) class and N ratio,and SPSS 15.0 software was used for statistical analysis.RESULTS:Ninety-six (44.4%) patients underwent D1 dissection and 120 (55.6%) had D2 dissection.When groups were evaluated,23 (24.0%) patients in D1 and 21 (17.5%) in D2 had stage migration (P=0.001).When both D1 and D2 groups were evaluated for number of pathological lymph nodes,despite the fact that there was no difference in N ratio between D1 and D2 groups,a statistically significant difference was found between them with regard to pN1 and pN2 groups (P=0.047,P=0.044 respectively).In D1,pN0 had the longest survival while pN3 had the shortest.In D2,pN0 had the longest survival whereas pN3 had the shortest survival.CONCLUSION:N ratio is an accurate staging system for defining prognosis and treatment plan,thus decreasing methodological errors in gastric cancer staging.
文摘Land cover change detection is the major goal in multitemporal remote sensing studies. It is well known that remotely-sensed images of the same area acquired on different dates tend to be affected by radiometric differences and registration problems. These influences are considered as noise in the process and may induce the user to both： signalling false changes and masking real surface changes. The difference image produced by subtracting two co-registered images is a standard initial step in change detection algorithms. This image naturally appears to be noisier than the original ones and has at least two populations： （1） the noise-like and （2） the real changes. The problem that arises is how to discriminate them. There are several approaches to perform change detection reported in the literature and some studies have employed synthetic images. By using synthetic images, the accuracy assessment of specific algorithm can be done more accurately. The question at this point is： what is the acceptable noise level to be added on the synthetic images to simulate a real problem？ This paper attempts to answer this question by suggesting values of SNR （signal-to-noise ratio） obtained from experiments performed on TM-Landsat-5 and CCD-CBERS-2B images.
