目的评估脑深部电刺激(DBS)系统在帕金森病(PD)丘脑底核(STN)刺激术后磁共振成像(MRI)的安全性,分析扫描前后的伪影大小及其对电极阻抗的影响。方法纳入2023年5月—2024年6月在北京协和医院行DBS植入术后的23例PD患者,对所有入组患者行...目的评估脑深部电刺激(DBS)系统在帕金森病(PD)丘脑底核(STN)刺激术后磁共振成像(MRI)的安全性,分析扫描前后的伪影大小及其对电极阻抗的影响。方法纳入2023年5月—2024年6月在北京协和医院行DBS植入术后的23例PD患者,对所有入组患者行头部1.5 T MRI,记录扫描前后电极各触点阻抗值、温度和特殊吸收率(SAR)值,比较扫描前后各参数差异;分析患者扫描所得MRI图像的伪影,比较两种不同序列伪影体积的差别;探究电极阻抗变化与伪影体积的相关性。结果所有患者在1.5 T MRI扫描前后的温度和电极阻抗值差异无统计学意义,T 1序列双侧伪影体积平均值均大于T 2序列(P=0.001);扫描前后电极阻抗值变化与伪影体积无显著相关(r=-0.268,P=0.355;r=-0.389,P=0.170)。结论DBS植入术后1.5 T MRI扫描具备临床安全性,双侧电极植入引起的图像伪影在不同序列以及不同侧别的体积大小不同,但与扫描前后的阻抗值变化无明显相关。展开更多
The major and trace elemental compositions of clinopyroxene from basalt were used to characterize the nature of the primitive magma and structural environment beneath the southern Okinawa Trough(SOT),which is an initi...The major and trace elemental compositions of clinopyroxene from basalt were used to characterize the nature of the primitive magma and structural environment beneath the southern Okinawa Trough(SOT),which is an initial back-arc basin at a continental margin.The clinopyroxenes in the basalt were augite with variable Mg^(#)contents(73.37-78.22).The regular variations in major oxide contents(i.e.,CaO,FeO,TiO_(2),and Cr)with decreasing Mg#implied that the clinopyroxenes evolved from being enriched in Mg,Ca,and Cr to being enriched in Fe and Ti.The clinopyroxenes had relatively low rare earth element concentrations(7.51×10^(-6) to 12.68×10^(-6))and negative Eu anomalies(δEu=0.67-0.95).The Kd_(cpx) values of clinopyroxenes(0.2-0.26),which were used to examine whether the clinopyroxene was equilibrated with its host basalt,demonstrate that these clinopyroxene phenocrysts were not captured crystals but were instead produced by crystallization differentiation of the magma.The calculated clinopyroxene crystallization temperatures showed a narrow range of 990-1061℃,and their crystallization pressures ranged from 2.0 to 3.2 kbar.The geochemistry features of these clinopyroxenes indicated that the parent magma belonged to the subalkaline tholeiitic magma series and suggested that the magma experienced crystallization differentiation of olivine,plagioclase,and clinopyroxene,where the crystallization of plagioclase occurred earlier than that of clinopyroxene.Combined with geophysical data,this research on primitive magma and its crystallization differentiation from clinopyroxene indicates that the SOT is in the stage of‘seafloor spreading’and that basaltic rocks produced from tholeiitic magma represent the generation of oceanic crust.展开更多
文摘目的评估脑深部电刺激(DBS)系统在帕金森病(PD)丘脑底核(STN)刺激术后磁共振成像(MRI)的安全性,分析扫描前后的伪影大小及其对电极阻抗的影响。方法纳入2023年5月—2024年6月在北京协和医院行DBS植入术后的23例PD患者,对所有入组患者行头部1.5 T MRI,记录扫描前后电极各触点阻抗值、温度和特殊吸收率(SAR)值,比较扫描前后各参数差异;分析患者扫描所得MRI图像的伪影,比较两种不同序列伪影体积的差别;探究电极阻抗变化与伪影体积的相关性。结果所有患者在1.5 T MRI扫描前后的温度和电极阻抗值差异无统计学意义,T 1序列双侧伪影体积平均值均大于T 2序列(P=0.001);扫描前后电极阻抗值变化与伪影体积无显著相关(r=-0.268,P=0.355;r=-0.389,P=0.170)。结论DBS植入术后1.5 T MRI扫描具备临床安全性,双侧电极植入引起的图像伪影在不同序列以及不同侧别的体积大小不同,但与扫描前后的阻抗值变化无明显相关。
基金supported by the National Natural Science Foundation of China(No.42276085)the National Basic Research Program of China(No.2013CB429702).
文摘The major and trace elemental compositions of clinopyroxene from basalt were used to characterize the nature of the primitive magma and structural environment beneath the southern Okinawa Trough(SOT),which is an initial back-arc basin at a continental margin.The clinopyroxenes in the basalt were augite with variable Mg^(#)contents(73.37-78.22).The regular variations in major oxide contents(i.e.,CaO,FeO,TiO_(2),and Cr)with decreasing Mg#implied that the clinopyroxenes evolved from being enriched in Mg,Ca,and Cr to being enriched in Fe and Ti.The clinopyroxenes had relatively low rare earth element concentrations(7.51×10^(-6) to 12.68×10^(-6))and negative Eu anomalies(δEu=0.67-0.95).The Kd_(cpx) values of clinopyroxenes(0.2-0.26),which were used to examine whether the clinopyroxene was equilibrated with its host basalt,demonstrate that these clinopyroxene phenocrysts were not captured crystals but were instead produced by crystallization differentiation of the magma.The calculated clinopyroxene crystallization temperatures showed a narrow range of 990-1061℃,and their crystallization pressures ranged from 2.0 to 3.2 kbar.The geochemistry features of these clinopyroxenes indicated that the parent magma belonged to the subalkaline tholeiitic magma series and suggested that the magma experienced crystallization differentiation of olivine,plagioclase,and clinopyroxene,where the crystallization of plagioclase occurred earlier than that of clinopyroxene.Combined with geophysical data,this research on primitive magma and its crystallization differentiation from clinopyroxene indicates that the SOT is in the stage of‘seafloor spreading’and that basaltic rocks produced from tholeiitic magma represent the generation of oceanic crust.
