We study Chaney's and Ben-Tal-Zowe's second-order directional derivatives with applications in minimization problem for max-functions of the formh(x): = max {f(x, τ); τ ∈T},where T is a compact metricspace....We study Chaney's and Ben-Tal-Zowe's second-order directional derivatives with applications in minimization problem for max-functions of the formh(x): = max {f(x, τ); τ ∈T},where T is a compact metricspace. We improve Kawasaki's result on necessary condition for such functions in the minimization problem.展开更多
文摘目的探讨^(18)F-PSMA PET/CT最大标准化摄取值(SUV max)在前列腺癌(PCa)与增生病变的鉴别诊断,以及在PCa预后预测中的价值。方法回顾性收集经病理证实、未经治疗的PCa同时伴有腺体增生的患者59例,治疗前行^(18)F-PSMA PET/CT全身显像,其中PCa灶86个,前列腺增生灶35个。比较良恶性病灶SUV max组间差异,绘制受试者工作特性曲线(ROC),获得cut-off值。进一步根据Gleason评分对PCa灶进行分组(≤6分为低危组,=7分为中危组,≥8为高危组),比较组间SUV max并进行事后检验分析,同时对癌灶SUV max与Gleason评分、前列腺特异性抗原(PSA)水平进行相关性分析。结果PCa灶的SUV max显著高于增生灶,两组间差异具有显著统计学意义(F=27.659,P<0.001),以SUV max 8.85作为cut-off值,ROC曲线下面积为0.843,诊断PCa的敏感性和特异性分别为69.77%和91.43%。PCa低、中、高危组SUV max差异无统计学意义(F=1.857,P=0.163),事后检验两两组间均未见统计学差异(P=0.744,P=0.191,P=0.075)。此外,PCa灶SUV max与Gleason评分、PSA之间差异均无统计学意义(P=0.248,P=0.101,P=0.064)。结论初步研究显示,^(18)F-PSMA PET/CT SUV max对前列腺病变良恶性鉴别具有较高价值,以SUV max 8.85作为cut-off值可获得较为理想的诊断效能。对于PCa分级及预后预测,^(18)F-PSMA PET/CT SUV max价值有限。
文摘We study Chaney's and Ben-Tal-Zowe's second-order directional derivatives with applications in minimization problem for max-functions of the formh(x): = max {f(x, τ); τ ∈T},where T is a compact metricspace. We improve Kawasaki's result on necessary condition for such functions in the minimization problem.
