The respiratory motion leads to significant motion artifacts of the positron emission tomography （PET） image, thus influencing diagnoses and treatments in the radiation oneology. The existing approaches to correct...The respiratory motion leads to significant motion artifacts of the positron emission tomography （PET） image, thus influencing diagnoses and treatments in the radiation oneology. The existing approaches to correct motion artifacts involve using gating devices and/or four-dimensional （4-D） computed tomography （CT）. However, they have the disadvantages of high CT dose and high computational burden. Hence, a sinusoid vibration model is presented to simulate the respiratory motion. The motion extent and the direction are derived from the Radon transform of the cepstrum of the blurred image. Then, two typical deeonvolution algorithms, i.e. , Wiener filter （WF） and the Richardson-Lucy （RL） algorithms are used to eliminate the motion blur according to the estimated parameters and their de-blurring results are compared. Experiments on both synthetic and phantom images show good performance of the presented model for identifying vibration modeled respiration motion and reducing the motion blur. The method has advantages of safety, convenience, and economy. And it is promising to correct the motion artifacts of the non-gated PET image.展开更多
利用行为学及复杂网络分析方法,探讨高特质焦虑(HTA)个体执行控制功能及其脑功能网络特点。以16名HTA个体为研究对象、16名低特质焦虑(LTA)个体为对照,进行Simon空间认知冲突任务,同步记录行为数据(反应时间及正确率)及64导脑电(EEG)信...利用行为学及复杂网络分析方法,探讨高特质焦虑(HTA)个体执行控制功能及其脑功能网络特点。以16名HTA个体为研究对象、16名低特质焦虑(LTA)个体为对照,进行Simon空间认知冲突任务,同步记录行为数据(反应时间及正确率)及64导脑电(EEG)信号。对EEG数据进行同步似然分析,选择合适阈值构建脑网络拓扑结构并计算网络整体属性参数及节点属性参数。利用方差分析方法,对两组被试的行为数据及脑网络属性参数进行统计学分析,结果显示,HTA组被试的冲突反应时间显著长于LTA组(641.29±72.11 vs 602.10±61.47,P<0.05)、反应正确率显著低于LTA组(90.73±2.14 vs 95.62±1.52,P<0.05),表明其认知冲突反应的效率降低、执行控制功能下降。对beta节律脑网络的分析显示:HTA组被试其额顶叶各节点的节点度值均显著小于LTA组(P<0.05),聚类系数(0.5341±0.0813 vs 0.6243±0.0527)及全局效率(0.0142±0.0037 vs 0.0185±0.0023)均显著小于LTA组(P<0.05),而特征路径长度显著大于LTA组(1.8057±0.0036 vs 1.4380±0.0117,P<0.05);高gamma节律脑网络的各属性参数结果与beta节律相似。以上结果表明HTA个体冲突监控、冲突解决等执行控制能力下降,其机制不仅与额顶执行控制网络功能受损有关,也与脑网络的整合功能及信息传输能力减弱有关。额顶执行控制网络功能受损、执行控制能力下降可能是HTA个体稳定、固有的特征。展开更多
基金Supported by the Science and Technology Foundation of Guangdong Province(2008B030303055)~~
文摘The respiratory motion leads to significant motion artifacts of the positron emission tomography （PET） image, thus influencing diagnoses and treatments in the radiation oneology. The existing approaches to correct motion artifacts involve using gating devices and/or four-dimensional （4-D） computed tomography （CT）. However, they have the disadvantages of high CT dose and high computational burden. Hence, a sinusoid vibration model is presented to simulate the respiratory motion. The motion extent and the direction are derived from the Radon transform of the cepstrum of the blurred image. Then, two typical deeonvolution algorithms, i.e. , Wiener filter （WF） and the Richardson-Lucy （RL） algorithms are used to eliminate the motion blur according to the estimated parameters and their de-blurring results are compared. Experiments on both synthetic and phantom images show good performance of the presented model for identifying vibration modeled respiration motion and reducing the motion blur. The method has advantages of safety, convenience, and economy. And it is promising to correct the motion artifacts of the non-gated PET image.
文摘利用行为学及复杂网络分析方法,探讨高特质焦虑(HTA)个体执行控制功能及其脑功能网络特点。以16名HTA个体为研究对象、16名低特质焦虑(LTA)个体为对照,进行Simon空间认知冲突任务,同步记录行为数据(反应时间及正确率)及64导脑电(EEG)信号。对EEG数据进行同步似然分析,选择合适阈值构建脑网络拓扑结构并计算网络整体属性参数及节点属性参数。利用方差分析方法,对两组被试的行为数据及脑网络属性参数进行统计学分析,结果显示,HTA组被试的冲突反应时间显著长于LTA组(641.29±72.11 vs 602.10±61.47,P<0.05)、反应正确率显著低于LTA组(90.73±2.14 vs 95.62±1.52,P<0.05),表明其认知冲突反应的效率降低、执行控制功能下降。对beta节律脑网络的分析显示:HTA组被试其额顶叶各节点的节点度值均显著小于LTA组(P<0.05),聚类系数(0.5341±0.0813 vs 0.6243±0.0527)及全局效率(0.0142±0.0037 vs 0.0185±0.0023)均显著小于LTA组(P<0.05),而特征路径长度显著大于LTA组(1.8057±0.0036 vs 1.4380±0.0117,P<0.05);高gamma节律脑网络的各属性参数结果与beta节律相似。以上结果表明HTA个体冲突监控、冲突解决等执行控制能力下降,其机制不仅与额顶执行控制网络功能受损有关,也与脑网络的整合功能及信息传输能力减弱有关。额顶执行控制网络功能受损、执行控制能力下降可能是HTA个体稳定、固有的特征。
