In this study, we analyzed diffusion tensor imaging （DTI） results of brain white matter in rhesus macaques （Macaca mulatta） with four different parameter settings and found that the sequence A （b=1000 s/mm^2, spa...In this study, we analyzed diffusion tensor imaging （DTI） results of brain white matter in rhesus macaques （Macaca mulatta） with four different parameter settings and found that the sequence A （b=1000 s/mm^2, spatial resolution=1.25 mm ×1.25 mm× 1.25 mm, numbers of direction=33, NSA=3） and B （b=800 s/mm^2, spatial resolution= 1.25 mm× 1.25 mm× 1.25 mm, numbers of direction=33, NSA=3） could accurately track coarse fibers. The fractional anisotropy （FA） derived from sequence C （b=1000s/mm^2, spatial resolution=0.55 mm×0.55 mm×2.5 mm, direction number=33, NSA=3） was too fuzzy to be used in tracking white matter fibers. By comparison, the high resolution and the FA with high contrast of gray matter and white matter derived from sequence D （b=800 s/mm^2, spatial resolution=1.0 mm×1.0 mm ×1.0 mm, numbers of direction=33, NSA=3） qualified in its application in tracking both thick and thin fibers, making it an optimal DTI setting for rhesus macaques.展开更多
Both functional magnetic resonance imaging （fMRI） and diffusion tensor imaging （DTI） can provide different information of the human brain, so using the wavelet transform method can achieve a fusion of these two ty...Both functional magnetic resonance imaging （fMRI） and diffusion tensor imaging （DTI） can provide different information of the human brain, so using the wavelet transform method can achieve a fusion of these two types of image data and can effectively improve the depression recognition accuracy. Multi-resolution wavelet decomposition is used to transform each type of images to the frequency domain in order to obtain the frequency components of the images. To each subject, decomposition components of two images are then added up separately according to their frequencies. The inverse discrete wavelet transform is used to reconstruct the fused images. After that, principal component analysis （PCA） is applied to reduce the dimension and obtain the features of the fusion data before classification. Based on the features of the fused images, an accuracy rate of 80. 95 % for depression recognition is achieved using a leave-one-out cross-validation test. It can be concluded that this wavelet fusion scheme has the ability to improve the current diagnosis of depression.展开更多
目的探讨DTI技术在微血管减压术治疗三叉神经痛中的应用价值。方法采用3.0 T MRI对22例三叉神经痛患者行3D-TOF序列和DTI成像,测量其患侧与健侧部分各向异性分数(FA)值、表观扩散系数(ADC)值。对两侧的参数值进行统计学分析。结果患侧...目的探讨DTI技术在微血管减压术治疗三叉神经痛中的应用价值。方法采用3.0 T MRI对22例三叉神经痛患者行3D-TOF序列和DTI成像,测量其患侧与健侧部分各向异性分数(FA)值、表观扩散系数(ADC)值。对两侧的参数值进行统计学分析。结果患侧三叉神经的FA值(0.23±0.08)显著低于健侧(0.47±0.09)(P<0.05);患侧三叉神经的ADC值[(2.98±0.45)×10-3mm2/s]明显高于健侧[(1.39±0.35)×10-3mm2/s](P<0.05)。微血管减压手术前患侧三叉神经的FA值、ADC值与术后的FA值(0.53±0.13)、ADC值[(1.40±0.39)×10-3mm2/s]比较,差异有统计学意义(均P<0.05)。微血管减压手术后患侧三叉神经的FA值、ADC值和健侧比较,差异无统计学意义(均P>0.05)。结论 DTI对判断血管压迫导致的三叉神经痛的影像学诊断和微血管减压术后疗效影像学评估有一定的临床参考价值。患侧三叉神经受压迫程度越大,ADC值越高,FA值越低。展开更多
目的 探讨结合DTI的短回波反转恢复各向同性变换角度RF激发3DT2TSE序列（SPACE：Sampling Perfection with Application optimized Contrasts using different flip angle evolutions）在腰骶丛病变成像中的应用价值。方法10例健康志愿...目的 探讨结合DTI的短回波反转恢复各向同性变换角度RF激发3DT2TSE序列（SPACE：Sampling Perfection with Application optimized Contrasts using different flip angle evolutions）在腰骶丛病变成像中的应用价值。方法10例健康志愿者和32例腰骶丛神经病变患者行常规扫描序列、3DSPACE STIR序列和DTI序列扫描。结果 10名健康自愿者,L1~S1腰骶神经根3DSPCACE STIR序列均得到清晰显示。32例腰骶丛神经病变中,神经根受推压移位27例,受侵犯5例。椎间盘突出所致神经根受损的FA值降低（P〈0.05）,而ADC值升高（P〈0.05）。结论 3DSPACE STIR序列具有较好的组织对比,图像可被作为测量DTI数据的FA值及ADC值的高分辨率蒙片,两者结合可以很好评估腰骶神经丛的神经压迫位置和神经受侵犯的范围和程度。展开更多
基金Foundation items： This work was supported by the 973 Program （2012CBB25503, 2011CB707800）,
文摘In this study, we analyzed diffusion tensor imaging （DTI） results of brain white matter in rhesus macaques （Macaca mulatta） with four different parameter settings and found that the sequence A （b=1000 s/mm^2, spatial resolution=1.25 mm ×1.25 mm× 1.25 mm, numbers of direction=33, NSA=3） and B （b=800 s/mm^2, spatial resolution= 1.25 mm× 1.25 mm× 1.25 mm, numbers of direction=33, NSA=3） could accurately track coarse fibers. The fractional anisotropy （FA） derived from sequence C （b=1000s/mm^2, spatial resolution=0.55 mm×0.55 mm×2.5 mm, direction number=33, NSA=3） was too fuzzy to be used in tracking white matter fibers. By comparison, the high resolution and the FA with high contrast of gray matter and white matter derived from sequence D （b=800 s/mm^2, spatial resolution=1.0 mm×1.0 mm ×1.0 mm, numbers of direction=33, NSA=3） qualified in its application in tracking both thick and thin fibers, making it an optimal DTI setting for rhesus macaques.
文摘类淋巴系统是近年发现的中枢神经系统内通过血管周围间隙执行代谢产物运输及代谢废物清除功能的系统,类淋巴系统功能下降与多种认知障碍疾病的发病机制相关。研究证实血管周围间隙扩散张量成像技术(diffusion tensor image analysis along the perivascular space,DTI-ALPS)所计算出的DTI-ALPS指数与阿尔茨海默病、帕金森、脑小血管病等疾病的认知功能障碍及疾病进展显著相关。本文将对DTI-ALPS技术在评估认知障碍疾病的类淋巴系统功能中的研究进展进行综述。
基金The National Natural Science Foundation of China(No.30900356,81071135)
文摘Both functional magnetic resonance imaging （fMRI） and diffusion tensor imaging （DTI） can provide different information of the human brain, so using the wavelet transform method can achieve a fusion of these two types of image data and can effectively improve the depression recognition accuracy. Multi-resolution wavelet decomposition is used to transform each type of images to the frequency domain in order to obtain the frequency components of the images. To each subject, decomposition components of two images are then added up separately according to their frequencies. The inverse discrete wavelet transform is used to reconstruct the fused images. After that, principal component analysis （PCA） is applied to reduce the dimension and obtain the features of the fusion data before classification. Based on the features of the fused images, an accuracy rate of 80. 95 % for depression recognition is achieved using a leave-one-out cross-validation test. It can be concluded that this wavelet fusion scheme has the ability to improve the current diagnosis of depression.
文摘目的探讨DTI技术在微血管减压术治疗三叉神经痛中的应用价值。方法采用3.0 T MRI对22例三叉神经痛患者行3D-TOF序列和DTI成像,测量其患侧与健侧部分各向异性分数(FA)值、表观扩散系数(ADC)值。对两侧的参数值进行统计学分析。结果患侧三叉神经的FA值(0.23±0.08)显著低于健侧(0.47±0.09)(P<0.05);患侧三叉神经的ADC值[(2.98±0.45)×10-3mm2/s]明显高于健侧[(1.39±0.35)×10-3mm2/s](P<0.05)。微血管减压手术前患侧三叉神经的FA值、ADC值与术后的FA值(0.53±0.13)、ADC值[(1.40±0.39)×10-3mm2/s]比较,差异有统计学意义(均P<0.05)。微血管减压手术后患侧三叉神经的FA值、ADC值和健侧比较,差异无统计学意义(均P>0.05)。结论 DTI对判断血管压迫导致的三叉神经痛的影像学诊断和微血管减压术后疗效影像学评估有一定的临床参考价值。患侧三叉神经受压迫程度越大,ADC值越高,FA值越低。
