目的 探讨单体位[头尾位(craniocaudal, CC)或内外侧斜位(mediolateral oblique, MLO)]数字化乳腺断层合成技术(digital breast tomosynthesis,DBT)联合全视野数字化乳腺X线摄影(full-fild digital mammography,FFDM)检查对乳腺癌的检...目的 探讨单体位[头尾位(craniocaudal, CC)或内外侧斜位(mediolateral oblique, MLO)]数字化乳腺断层合成技术(digital breast tomosynthesis,DBT)联合全视野数字化乳腺X线摄影(full-fild digital mammography,FFDM)检查对乳腺癌的检出率和诊断效能。方法 选取141例乳腺病变患者影像学资料,患者同时行乳腺DBT和FFDM检查。由2位放射科诊断医师分别对患者DBT图像进行单体位和双体位(CC+MLO)阅片并联合FFDM,以病理结果为金标准。分析单体位和双体位DBT检查联合FFDM检查对患者乳腺良恶性病灶的检出率及诊断效能。结果 141例患者按照ACR2013版BI-RADS系统分类标准:a类3例、b类40例、c类84例、d类14例。根据BI-RADS评级标准,2位放射科诊断医师采用四种诊断方式(DBT-CC,DBT-MLO及双体位DBT分别联合FFDM及单独FFDM)进行诊断。结论 采用DBT+FFDM的阅片方式无论是单体位还是双体位的结果假阳性率及假阴性率均低于FFDM,诊断的准确度、特异度及灵敏度均高于FFDM,对高/低年资诊断医师FFDM+DBT双体位的诊断效能高于单体位,在FFDM+DBT-CC和FFDM+DBT-MLO单体位之间准确度、灵敏度和特异度MLO均高于CC位。展开更多
匹配是一个边的集合,其中任意两条边都没有公共顶点。对于图G的一个匹配M,如果M中的边能够将G的所有顶点两两配对,则称该匹配为完美匹配。七个苯环生成的六角系统中具有完美匹配的六角系统个数为190个。本文计算出了这190个七个苯环生...匹配是一个边的集合,其中任意两条边都没有公共顶点。对于图G的一个匹配M,如果M中的边能够将G的所有顶点两两配对,则称该匹配为完美匹配。七个苯环生成的六角系统中具有完美匹配的六角系统个数为190个。本文计算出了这190个七个苯环生成的六角系统的双强迫多项式。同时将双强迫多项式、强迫多项式、反强迫多项式、完美匹配个数、自由度与反自由度对于图的区分情况进行了统计与比较。A matching is a set of edges, where any two edges have no common vertices. For a match M in graph G, if the edges in M can pair all the vertices of G in pairs, the match is said to be a perfect match. The number of hexagonal systems with perfect matchings among the hexagonal systems generated by seven benzene rings is 190. This paper calculates the di-forcing polynomials of the hexagonal system generated by these 190 seven benzene rings. At the same time, the discrimination of di-forcing polynomials, forced polynomials, anti-forced polynomials, number of perfect matches, degrees of freedom and anti-degrees of freedom for graphs is statistically compared.展开更多
六角系统是一个2-连通的有限平面二部图,其中每个内面边界都是单位的正六边形。具有凯库勒结构的六角系统H的双强迫多项式是H的所有完美匹配的强迫数和反强迫数的二元计数多项式。本文计算了苯环数目不超过六的六角系统的双强迫多项式,...六角系统是一个2-连通的有限平面二部图,其中每个内面边界都是单位的正六边形。具有凯库勒结构的六角系统H的双强迫多项式是H的所有完美匹配的强迫数和反强迫数的二元计数多项式。本文计算了苯环数目不超过六的六角系统的双强迫多项式,由此得到其强迫多项式,反强迫多项式,内自由度与外自由度,为六角系统的结构分析提供了新的数学工具和结果。The hexagonal system is a 2-connected finite plane bipartite graph, in which each inner boundary is a regular hexagon of a unit. The di-forcing polynomials of hexagonal systems H with Kekulé structure are the binary counting polynomials of all perfect matchings forcing and anti-forcing numbers of H. In this paper, the di-forcing polynomials of hexagonal systems with no more than six benzene rings are calculated, from which the forcing polynomials, anti-forcing polynomials, internal and external degrees of freedom are obtained, it provides a new mathematical tool and results for the structural analysis of hexagonal system.展开更多
文摘匹配是一个边的集合,其中任意两条边都没有公共顶点。对于图G的一个匹配M,如果M中的边能够将G的所有顶点两两配对,则称该匹配为完美匹配。七个苯环生成的六角系统中具有完美匹配的六角系统个数为190个。本文计算出了这190个七个苯环生成的六角系统的双强迫多项式。同时将双强迫多项式、强迫多项式、反强迫多项式、完美匹配个数、自由度与反自由度对于图的区分情况进行了统计与比较。A matching is a set of edges, where any two edges have no common vertices. For a match M in graph G, if the edges in M can pair all the vertices of G in pairs, the match is said to be a perfect match. The number of hexagonal systems with perfect matchings among the hexagonal systems generated by seven benzene rings is 190. This paper calculates the di-forcing polynomials of the hexagonal system generated by these 190 seven benzene rings. At the same time, the discrimination of di-forcing polynomials, forced polynomials, anti-forced polynomials, number of perfect matches, degrees of freedom and anti-degrees of freedom for graphs is statistically compared.
文摘六角系统是一个2-连通的有限平面二部图,其中每个内面边界都是单位的正六边形。具有凯库勒结构的六角系统H的双强迫多项式是H的所有完美匹配的强迫数和反强迫数的二元计数多项式。本文计算了苯环数目不超过六的六角系统的双强迫多项式,由此得到其强迫多项式,反强迫多项式,内自由度与外自由度,为六角系统的结构分析提供了新的数学工具和结果。The hexagonal system is a 2-connected finite plane bipartite graph, in which each inner boundary is a regular hexagon of a unit. The di-forcing polynomials of hexagonal systems H with Kekulé structure are the binary counting polynomials of all perfect matchings forcing and anti-forcing numbers of H. In this paper, the di-forcing polynomials of hexagonal systems with no more than six benzene rings are calculated, from which the forcing polynomials, anti-forcing polynomials, internal and external degrees of freedom are obtained, it provides a new mathematical tool and results for the structural analysis of hexagonal system.
