目的探讨压缩感知(Compressed Sensing,CS)技术在屏气磁共振胰胆管造影(Magnetic Resonance Cholangiopancreatography,MRCP)中的临床应用价值。方法对40例患者同时行膈肌导航3D可变反转角快速自旋回波(Sampling Perfection with Applic...目的探讨压缩感知(Compressed Sensing,CS)技术在屏气磁共振胰胆管造影(Magnetic Resonance Cholangiopancreatography,MRCP)中的临床应用价值。方法对40例患者同时行膈肌导航3D可变反转角快速自旋回波(Sampling Perfection with Application-Optimized Contrast Using Different Flip-Angle Evolutions,SPACE)MRCP和屏气压缩感知3D MRCP(欠采样率3.6%)序列扫描,根据序列不同将图像分为SPACE-MRCP和CS-MRCP 2组。定性分析2组图像整体质量、背景抑制效果和胰管的显示能力;定量分析2组图像的扫描时间、信噪比(Signal to Noise Ratio,SNR)和对比噪声比(Contrast to Noise Ratio,CNR)。结果图像整体质量评分、背景抑制效果方面,CS-MRCP均优于SPACE-MRCP,差异有统计学意义(P<0.05)。胰管显示能力方面,CS-MRCP与SPACE-MRCP相当,差异无统计学意义(P<0.05);SPACE-MRCP和CS-MRCP扫描时间分别为(260.95±61.70)、17 s,差异有统计学意义(P<0.05)。SNR和CNR分析中,CS-MRCP均优于SPACE-MRCP,差异有统计学意义(P<0.05)。结论采用压缩感知技术的屏气MRCP序列与膈肌导航3D SPACE序列相比,可显著缩短扫描时间,获得更好的图像质量。展开更多
目的探讨静脉输液港植入输液针后在磁共振检查中的安全性。方法将两个公司生产的不同型号的静脉输液港和输液针放在磁共振中进行偏移力测量,记录测量结果;应用磁共振发热极端序列扫描,分别测量不同输液针与4种输液港组合的温度升高情况...目的探讨静脉输液港植入输液针后在磁共振检查中的安全性。方法将两个公司生产的不同型号的静脉输液港和输液针放在磁共振中进行偏移力测量,记录测量结果;应用磁共振发热极端序列扫描,分别测量不同输液针与4种输液港组合的温度升高情况;对带输液针的静脉输液港植入后患者进行安全性观察。结果不同厂家不同型号的输液港港体和输液针在入口处偏移角度0°~55°,在机器中均不发生偏转;所有输液针与输液港组合与单独输液港温度差在0.5℃~1.2℃之间,最大差值1.8℃;所有20例带输液针的静脉输液港植入患者体内后,在3.0 T MR入口及机器中均未见输液针和输液港移位,港体未见有损坏、渗液、贴膜松动等现象,患者无不适症状。结论静脉输液港植入输液针后,在3.0 T MR检查中是安全的。展开更多
目的比较优化短反转恢复(Short TI Inversion Recovery,STIR)和三点非对称法脂肪抑制技术(Iterative Dixon of Water-fat with Echo Asymmetry and Least-squares Estimation,IDEAL)对金属植入物磁共振成像(Magnetic Resonance Imaging,...目的比较优化短反转恢复(Short TI Inversion Recovery,STIR)和三点非对称法脂肪抑制技术(Iterative Dixon of Water-fat with Echo Asymmetry and Least-squares Estimation,IDEAL)对金属植入物磁共振成像(Magnetic Resonance Imaging,MRI)图像质量的影响。方法选取腰椎金属内固定术后需行MRI检查的患者30例,行常规序列以及优化STIR、IDEAL序列扫描,通过对感兴趣区信号的强度值分别计算信噪比(Signal to Noise Ratio,SNR)和信噪比(Contrast to Noise Ratio,CNR),对数据结果做统计学分析;对脂肪抑制均匀性、金属伪影大小进行主观评价。结果优化STIR和IDEAL两种方法图像信噪比分别为:19.26±0.96、20.26±1.24(t=-2.94,P<0.01);图像噪声比分别为:7.03±0.94、8.28±0.97(t=-6.07,P<0.01);主观评分脂肪抑制的均匀性分别为:3.47±0.51、3.63±0.50(t=1.37,P>0.05);金属伪影的大小分别为:3.68±0.67,3.74±0.65(t=-0.57,P>0.05)。结论IDEAL技术在脂肪抑制均匀性、金属伪影、图像信噪比等图像质量方面和优化STIR脂肪抑制技术相当,并且可以得到更好的SNR和CNR。因此在机器条件允许的情况下,对于金属植入物的患者可以选择IDEAL脂肪抑制技术进行检查。展开更多
目的对比频率选择脂肪抑制技术(Frequency-Selective Fat Saturation,FS),探讨非对称回波的最小二程估算法迭代水脂分离(Iterative Dixon of Water-fat with Echo Asymmetry and Least-squares Estimation,IDEAL)技术在金属植入物患者...目的对比频率选择脂肪抑制技术(Frequency-Selective Fat Saturation,FS),探讨非对称回波的最小二程估算法迭代水脂分离(Iterative Dixon of Water-fat with Echo Asymmetry and Least-squares Estimation,IDEAL)技术在金属植入物患者磁共振检查中应用价值。方法选取体内(腰椎、颈椎、骨盆等)含有金属内固定行MRI检查的患者20例,做常规序列扫描及加FS、IDEAL序列扫描,对所得图像通过软件获得感兴趣区信号的强度值分别计算信噪比(Signal to Noise Ratio,SNR)和对比噪声比(Contrast to Noise Ratio,CNR),记录数据结果并做统计学分析;对脂肪抑制均匀性、金属伪影大小应用主观法进行评价。结果FS和IDEAL两种脂肪抑制方法图像SNR分别为:10.9±0.3、20.3±1.2(t=-34.3,P<0.01);图像CNR分别为5.8±0.3、8.3±1.0(t=-11.6,P<0.01);主观评分脂肪抑制均匀性分别为:2.8±0.5、3.6±0.5(t=-6.4,P<0.01);图像金属伪影大小分别为:2.8±0.6,3.7±0.7(t=-5.9,P<0.01)。结论相比于FS,IDEAL脂肪抑制技术能显著减少金属伪影,提供更加均匀的脂肪抑制图像,提高被检部位和周围软组织结构的显示效果,更有利于病灶检出及临床诊断。展开更多
The Solar Polar ORbit Telescope(SPORT) project for space weather mission has been under intensive scientific and engineering background studies since it was incorporated into the Chinese Space Science Strategic Pionee...The Solar Polar ORbit Telescope(SPORT) project for space weather mission has been under intensive scientific and engineering background studies since it was incorporated into the Chinese Space Science Strategic Pioneer Project in 2011.SPORT is designed to carry a suite of remote-sensing and in-situ instruments to observe Coronal Mass Ejections(CMEs),energetic particles,solar high-latitude magnetism,and the fast solar wind from a polar orbit around the Sun.The first extended view of the polar regions of the Sun and the ecliptic enabled by SPORT will provide a unique opportunity to study CME propagation through the inner heliosphere,and the solar high-latitude magnetism giving rise to eruptions and the fast solar wind.Coordinated observations between SPORT and other spaceborne/ground-based facilities within the International Living With a Star(ILWS) framework can significantly enhance scientific output.SPORT is now competing for official selection and implementation during China's 13 th Five-Year Plan period of 2016-2020.展开更多
目的探究自监督学习网络Patch2Self在多层同时扫描扩散张量成像(Multiband SENSE Diffusion Tensor Imaging,MB SENSE DTI)中降噪的可行性。方法招募24名健康志愿在3T MRI上进行MB SENSE(MB factor 4)DTI扫描。利用自监督学习网络Patch2...目的探究自监督学习网络Patch2Self在多层同时扫描扩散张量成像(Multiband SENSE Diffusion Tensor Imaging,MB SENSE DTI)中降噪的可行性。方法招募24名健康志愿在3T MRI上进行MB SENSE(MB factor 4)DTI扫描。利用自监督学习网络Patch2Self、非局部均值法(Non-Local Means,NLM)和局部主成分分析法(Local Principal Component Analysis,LPCA)给MB SENSE DTI去噪。使用峰值噪声比(Peak Signal to Noise Ratio,PSNR)、结构相似度(Structural Similarity,SSIM)进行客观评价;由放射科医生对图像噪声、对比度、整体质量以及各向异性分数(Fractional anisotropy,FA)图的整体质量进行主观评价。结果在PSNR方面,Patch2Self优于NLM,但低于LPCA(P<0.05);在SSIM方面,Patch2Self优于NLM和LPCA(P<0.05);在噪声方面,Patch2Self明显优于NLM(P<0.05),而Patch2Self与LPCA之间图像质量比较无统计学差异(P>0.05);在对比度、整体质量和FA图的整体质量方面,Patch2Self优于NLM和LPCA(P<0.05)。结论自监督学习网络Patch2Self可以很好地完成去噪、保留脑部组织结构以及提高图像质量。展开更多
CMEs(Coronal Mass Ejections) are an important means of energy release in the solar corona.Solar Polar Orbit Radio Telescope(SPORT) is a mission being proposed for observing the propagation of interplanetary CMEs from ...CMEs(Coronal Mass Ejections) are an important means of energy release in the solar corona.Solar Polar Orbit Radio Telescope(SPORT) is a mission being proposed for observing the propagation of interplanetary CMEs from solar polar orbit.The main payload onboard SPORT is a synthetic aperture interferometric radiometer,which receives radio emission of interplanetary CMEs. It is identified that there are mainly three radio emission mechanisms of CMEs,i.e.,bremsstrahlung, gyrosynchrotron emission and plasma emission.Among these emission types,bremsstrahlung emission is the main emission mechanism of the high-density plasma clouds of interplanetary CMEs.Gyrosynchrotron emission is the continuous emission generated by high-energy electrons from CMEs, while plasma emission is the main mechanism of transient radio bursts from CMEs.In this paper,the gyrosynchrotron emission of interplanetary CMEs is focused on.Firstly,the mechanism of gyrosynchrotron emission is reviewed.Secondly,a review of the physical parameter models of background solar wind and interplanetary CMEs is presented.After these,the brightness temperature and polarization of gyrosynchrotron emission of interplanetary CMEs are calculated and analyzed.Finally, the detectability of gyrosynchrotron emission of interplanetary CMEs by radio meters is discussed briefly.展开更多
文摘目的探讨压缩感知(Compressed Sensing,CS)技术在屏气磁共振胰胆管造影(Magnetic Resonance Cholangiopancreatography,MRCP)中的临床应用价值。方法对40例患者同时行膈肌导航3D可变反转角快速自旋回波(Sampling Perfection with Application-Optimized Contrast Using Different Flip-Angle Evolutions,SPACE)MRCP和屏气压缩感知3D MRCP(欠采样率3.6%)序列扫描,根据序列不同将图像分为SPACE-MRCP和CS-MRCP 2组。定性分析2组图像整体质量、背景抑制效果和胰管的显示能力;定量分析2组图像的扫描时间、信噪比(Signal to Noise Ratio,SNR)和对比噪声比(Contrast to Noise Ratio,CNR)。结果图像整体质量评分、背景抑制效果方面,CS-MRCP均优于SPACE-MRCP,差异有统计学意义(P<0.05)。胰管显示能力方面,CS-MRCP与SPACE-MRCP相当,差异无统计学意义(P<0.05);SPACE-MRCP和CS-MRCP扫描时间分别为(260.95±61.70)、17 s,差异有统计学意义(P<0.05)。SNR和CNR分析中,CS-MRCP均优于SPACE-MRCP,差异有统计学意义(P<0.05)。结论采用压缩感知技术的屏气MRCP序列与膈肌导航3D SPACE序列相比,可显著缩短扫描时间,获得更好的图像质量。
文摘目的探讨静脉输液港植入输液针后在磁共振检查中的安全性。方法将两个公司生产的不同型号的静脉输液港和输液针放在磁共振中进行偏移力测量,记录测量结果;应用磁共振发热极端序列扫描,分别测量不同输液针与4种输液港组合的温度升高情况;对带输液针的静脉输液港植入后患者进行安全性观察。结果不同厂家不同型号的输液港港体和输液针在入口处偏移角度0°~55°,在机器中均不发生偏转;所有输液针与输液港组合与单独输液港温度差在0.5℃~1.2℃之间,最大差值1.8℃;所有20例带输液针的静脉输液港植入患者体内后,在3.0 T MR入口及机器中均未见输液针和输液港移位,港体未见有损坏、渗液、贴膜松动等现象,患者无不适症状。结论静脉输液港植入输液针后,在3.0 T MR检查中是安全的。
文摘目的比较优化短反转恢复(Short TI Inversion Recovery,STIR)和三点非对称法脂肪抑制技术(Iterative Dixon of Water-fat with Echo Asymmetry and Least-squares Estimation,IDEAL)对金属植入物磁共振成像(Magnetic Resonance Imaging,MRI)图像质量的影响。方法选取腰椎金属内固定术后需行MRI检查的患者30例,行常规序列以及优化STIR、IDEAL序列扫描,通过对感兴趣区信号的强度值分别计算信噪比(Signal to Noise Ratio,SNR)和信噪比(Contrast to Noise Ratio,CNR),对数据结果做统计学分析;对脂肪抑制均匀性、金属伪影大小进行主观评价。结果优化STIR和IDEAL两种方法图像信噪比分别为:19.26±0.96、20.26±1.24(t=-2.94,P<0.01);图像噪声比分别为:7.03±0.94、8.28±0.97(t=-6.07,P<0.01);主观评分脂肪抑制的均匀性分别为:3.47±0.51、3.63±0.50(t=1.37,P>0.05);金属伪影的大小分别为:3.68±0.67,3.74±0.65(t=-0.57,P>0.05)。结论IDEAL技术在脂肪抑制均匀性、金属伪影、图像信噪比等图像质量方面和优化STIR脂肪抑制技术相当,并且可以得到更好的SNR和CNR。因此在机器条件允许的情况下,对于金属植入物的患者可以选择IDEAL脂肪抑制技术进行检查。
文摘目的对比频率选择脂肪抑制技术(Frequency-Selective Fat Saturation,FS),探讨非对称回波的最小二程估算法迭代水脂分离(Iterative Dixon of Water-fat with Echo Asymmetry and Least-squares Estimation,IDEAL)技术在金属植入物患者磁共振检查中应用价值。方法选取体内(腰椎、颈椎、骨盆等)含有金属内固定行MRI检查的患者20例,做常规序列扫描及加FS、IDEAL序列扫描,对所得图像通过软件获得感兴趣区信号的强度值分别计算信噪比(Signal to Noise Ratio,SNR)和对比噪声比(Contrast to Noise Ratio,CNR),记录数据结果并做统计学分析;对脂肪抑制均匀性、金属伪影大小应用主观法进行评价。结果FS和IDEAL两种脂肪抑制方法图像SNR分别为:10.9±0.3、20.3±1.2(t=-34.3,P<0.01);图像CNR分别为5.8±0.3、8.3±1.0(t=-11.6,P<0.01);主观评分脂肪抑制均匀性分别为:2.8±0.5、3.6±0.5(t=-6.4,P<0.01);图像金属伪影大小分别为:2.8±0.6,3.7±0.7(t=-5.9,P<0.01)。结论相比于FS,IDEAL脂肪抑制技术能显著减少金属伪影,提供更加均匀的脂肪抑制图像,提高被检部位和周围软组织结构的显示效果,更有利于病灶检出及临床诊断。
基金Supported by the Strategic Priority Research Program on Space Science(XDA04060801,XDA04060802,XDA04060803,XDA04060804)of Chinese Academy of Sciencesthe Specialized Research Fund for State Key Laboratory of China+1 种基金the Chinese National Science Foundation(41374175,41204129)the CAS/SAFEA international Partnership Program for Creative Research Teams
文摘The Solar Polar ORbit Telescope(SPORT) project for space weather mission has been under intensive scientific and engineering background studies since it was incorporated into the Chinese Space Science Strategic Pioneer Project in 2011.SPORT is designed to carry a suite of remote-sensing and in-situ instruments to observe Coronal Mass Ejections(CMEs),energetic particles,solar high-latitude magnetism,and the fast solar wind from a polar orbit around the Sun.The first extended view of the polar regions of the Sun and the ecliptic enabled by SPORT will provide a unique opportunity to study CME propagation through the inner heliosphere,and the solar high-latitude magnetism giving rise to eruptions and the fast solar wind.Coordinated observations between SPORT and other spaceborne/ground-based facilities within the International Living With a Star(ILWS) framework can significantly enhance scientific output.SPORT is now competing for official selection and implementation during China's 13 th Five-Year Plan period of 2016-2020.
文摘目的探究自监督学习网络Patch2Self在多层同时扫描扩散张量成像(Multiband SENSE Diffusion Tensor Imaging,MB SENSE DTI)中降噪的可行性。方法招募24名健康志愿在3T MRI上进行MB SENSE(MB factor 4)DTI扫描。利用自监督学习网络Patch2Self、非局部均值法(Non-Local Means,NLM)和局部主成分分析法(Local Principal Component Analysis,LPCA)给MB SENSE DTI去噪。使用峰值噪声比(Peak Signal to Noise Ratio,PSNR)、结构相似度(Structural Similarity,SSIM)进行客观评价;由放射科医生对图像噪声、对比度、整体质量以及各向异性分数(Fractional anisotropy,FA)图的整体质量进行主观评价。结果在PSNR方面,Patch2Self优于NLM,但低于LPCA(P<0.05);在SSIM方面,Patch2Self优于NLM和LPCA(P<0.05);在噪声方面,Patch2Self明显优于NLM(P<0.05),而Patch2Self与LPCA之间图像质量比较无统计学差异(P>0.05);在对比度、整体质量和FA图的整体质量方面,Patch2Self优于NLM和LPCA(P<0.05)。结论自监督学习网络Patch2Self可以很好地完成去噪、保留脑部组织结构以及提高图像质量。
基金Supported by the National Natural Science Foundation of China(No.40574070)China Post-doctor Foundation
文摘CMEs(Coronal Mass Ejections) are an important means of energy release in the solar corona.Solar Polar Orbit Radio Telescope(SPORT) is a mission being proposed for observing the propagation of interplanetary CMEs from solar polar orbit.The main payload onboard SPORT is a synthetic aperture interferometric radiometer,which receives radio emission of interplanetary CMEs. It is identified that there are mainly three radio emission mechanisms of CMEs,i.e.,bremsstrahlung, gyrosynchrotron emission and plasma emission.Among these emission types,bremsstrahlung emission is the main emission mechanism of the high-density plasma clouds of interplanetary CMEs.Gyrosynchrotron emission is the continuous emission generated by high-energy electrons from CMEs, while plasma emission is the main mechanism of transient radio bursts from CMEs.In this paper,the gyrosynchrotron emission of interplanetary CMEs is focused on.Firstly,the mechanism of gyrosynchrotron emission is reviewed.Secondly,a review of the physical parameter models of background solar wind and interplanetary CMEs is presented.After these,the brightness temperature and polarization of gyrosynchrotron emission of interplanetary CMEs are calculated and analyzed.Finally, the detectability of gyrosynchrotron emission of interplanetary CMEs by radio meters is discussed briefly.