To attain the volumetric information of the optic radiation in normal human brains, we per- formed diffusion tensor imaging examination in 13 healthy volunteers. Simultaneously, we used a brain normalization method to...To attain the volumetric information of the optic radiation in normal human brains, we per- formed diffusion tensor imaging examination in 13 healthy volunteers. Simultaneously, we used a brain normalization method to reduce individual brain variation and increase the accuracy of volumetric information analysis. In addition, tractography-based group mapping method was also used to investigate the probability and distribution of the optic radiation pathways. Our results showed that the measured optic radiation fiber tract volume was a range of about 0.16% and that the fractional anisotropy value was about 0.53. Moreover, the optic radiation probability fiber pathway that was determined with diffusion tensor tractography-based group mapping was able to detect the location relatively accurately. We believe that our methods and results are help- ful in the study of optic radiation fiber tract information.展开更多
Purpose: To determine the total direct costs (fixed and variable costs) of diffusion tensor imaging (DTI) and MR tractography reconstruction of the brain. Materials and Methods: The direct fixed and variable costs of ...Purpose: To determine the total direct costs (fixed and variable costs) of diffusion tensor imaging (DTI) and MR tractography reconstruction of the brain. Materials and Methods: The direct fixed and variable costs of DTI with MR tractography were determined prospectively with time and motion analysis in a 1.5-Tesla MR scanner using 15 encoding directions. Seventeen patients with seizure disorders, 9 males & 8 females, with mean age of 13 years (age range 2 - 33 years) were studied. Total direct costs were calculated from all direct fixed and variable costs. Sensitivity analyses between 1.5 versus a 3-Tesla MR system, and 15 versus 32 encoding directions were done. Results: The total direct costs of DTI and MR tractography for a 1.5-T system with 15 encoding directions were US $97. Variable cost was $76.80 and fixed cost was $20.20. Total direct costs for a 3-T system with 15 directions decreased to US $94.5 because of the shorter scan time despite the higher cost of the 3-T system. The most costly component of the direct cost was post-processing analysis at US $46.00. Conclusion: DTI with MR tractography has important total direct costs with variable costs higher than the fixed costs. The post processing variable cost is the most expensive component. Developing more accurate automated post-processing software for DTI and MR tractography is important to decrease this variable labor cost. Given the added value of DTI-MR tractography and the costs involved reimbursement codes should be considered.展开更多
BACKGROUND： Previous studies regarding primary progressive aphasia （PPA） have focused on progressive, non-fluent aphasia. Little information is available with regard to the use of diffusion tensor imaging compared ...BACKGROUND： Previous studies regarding primary progressive aphasia （PPA） have focused on progressive, non-fluent aphasia. Little information is available with regard to the use of diffusion tensor imaging compared with conventional magnetic resonance imaging for the detection of subtle structural abnormalities. OBJECTIVE： To investigate and localize brain abnormalities in a Chinese patient with semantic dementia. DESIGN, TIME AND SETTING： A concurrent, non-randomized, case-controlled, neuroimaging, clinical trial was performed at the Department of Radiology, West China Hospital of Sichuan University in March 2009. PARTICIPANTS： One 75-year-old male patient, who was diagnosed with semantic dementia, and 21 age- and gender-matched healthy volunteers were recruited for the study. METHODS： Diffusion tensor imaging was used to determine mean diffusion （MD） and fractional anisotropy （FA） in the brains of the patient and the 21 healthy subjects. Voxel-based analysis of MD and FA values was performed using statistical parametric mapping. MAIN OUTCOME MEASURES： MD and FA value maps differences between patient and controls. RESULTS： MD was significantly increased in both cerebra, but was predominant on the left side and expanded to outside of the language-related region. Reduced MD was not detected in any of the brains. FA was shown to be decreased in the corpus callosum, but was increased in the basal ganglia. CONCLUSION： The present study provided clear in vivo magnetic imaging evidence of diffuse brain involvement in semantic dementia. Increases in MD were greater than in FA when brain diffusion alterations were detected, which suggested that MD could be a better marker of disease progression.展开更多
Proton magnetic resonance spectroscopy and diffusion tensor imaging are non-invasive techniques used to detect metabolites and water diffusion in vivo. Previous studies have confirmed a positive correlation of individ...Proton magnetic resonance spectroscopy and diffusion tensor imaging are non-invasive techniques used to detect metabolites and water diffusion in vivo. Previous studies have confirmed a positive correlation of individual fractional anisotropy values with N-acetylaspartate/creatine and N-acetylaspartate/choline ratios in tumors, edema, and normal white matter. This study divided the brain parenchyma into tumor, pedtumoral edema, and normal-appearing white matter according to MRI data, and analyzed the correlation of metabolites with water molecular diffusion. Results demonstrated that in normal-appearing white matter, N-acetylaspartate/creatine ratios were positively correlated with fractional anisotropy values, negatively correlated with radial diffusivities, and positively correlated with maximum eigenvalues. Maximum eigenvalues and radial diffusivities in peritumoral edema showed a negative correlation with choline, N-acetylaspartate, and creatine. Radial diffusivities in tumor demonstrated a negative correlation with choline. These data suggest that the relationship between metabolism and structure is markedly changed from normal white matter to peritumoral edema and tumor. Neural metabolism in the peritumoral edema area decreased with expanding extracellular space. The normal relationship of neural function and microstructure disappeared in the tumor region.展开更多
类淋巴系统(glymphatic system,GS)是大脑中废物清除的途径,其功能受损可以通过沿血管周围间隙扩散张量成像分析(diffusion tensor imaging analysis along the perivascular space,DTI-ALPS)进行评估。目前,DTI-ALPS作为一种非侵入性...类淋巴系统(glymphatic system,GS)是大脑中废物清除的途径,其功能受损可以通过沿血管周围间隙扩散张量成像分析(diffusion tensor imaging analysis along the perivascular space,DTI-ALPS)进行评估。目前,DTI-ALPS作为一种非侵入性方法已被广泛用于评估神经系统疾病中的GS功能改变,它在评估神经系统疾病的病程进展、认知障碍及预测预后等方面发挥了举足轻重的作用。本文就GS、DTI-ALPS方法与应用优势及其在神经系统疾病中的应用进行综述,旨在为神经系统疾病的病程进展、预测影响预后因素以及临床治疗疗效方面提供一定的参考。展开更多
Background Diffusion tensor imaging （DTI） permits quantitative examination within the pyramidal tract （PT） by measuring fractional anisotropy （FA）. To the best of our knowledge, the inter-variability measures of...Background Diffusion tensor imaging （DTI） permits quantitative examination within the pyramidal tract （PT） by measuring fractional anisotropy （FA）. To the best of our knowledge, the inter-variability measures of FA along the PT remain unexplained. A clear understanding of these reference values would help radiologists and neuroscientists to understand normality as well as to detect early pathophysiologic changes of brain diseases. The aim of our study was to calculate the variability of the FA at eleven anatomical landmarks along the PT and the influences of gender and cerebral hemisphere in these measurements in a sample of young, healthy volunteers. Methods A retrospective, cross-sectional study was performed in twenty-three right-handed healthy volunteers who underwent magnetic resonance evaluation of the brain. Mean FA values from eleven anatomical landmarks across the PT （at centrum semiovale, corona radiata, posterior limb of internal capsule （PLIC）, mesencephalon, pons, and medulla oblongata） were evaluated using split-plot factorial analysis of variance （ANOVA）. Results We found a significant interaction effect between anatomical landmark and cerebral hemisphere （F （10, 32）=4.516, P=0.001; Wilks＇ Lambda 0.415, with a large effect size （partial η2=0.585））. The influence of gender and age was non-significant. On average, the midbrain and PLIC FA values were higher than pons and medulla oblongata values; centrum semiovale measurements were higher than those of the corona radiata but lower than PLIC. Conclusions There is a normal variability of FA measurements along PT in healthy individuals, which is influenced by regions of interest location （anatomical landmarks） and cerebral hemisphere. FA measurements should be reported for comparing same-side and same-landmark PT to help avoid comparisons with the contralateral PT; ideally, normative values should exist for a clinically significant age group. A standardized package of selected DTI processing tools would allow DTI processing to be routinely performed in clinical settings.展开更多
BACKGROUND Dysfunction of the glymphatic system in the brain in different stages of altered glucose metabolism and its influencing factors are not well characterized.AIM To investigate the function of the glymphatic s...BACKGROUND Dysfunction of the glymphatic system in the brain in different stages of altered glucose metabolism and its influencing factors are not well characterized.AIM To investigate the function of the glymphatic system and its clinical correlates in patients with different glucose metabolism states,the present study employed diffusion tensor imaging along the perivascular space(DTI-ALPS)index.METHODS Sample size was calculated using the pwr package in R software.This crosssectional study enrolled 22 patients with normal glucose metabolism(NGM),20 patients with prediabetes,and 22 patients with type 2 diabetes mellitus(T2DM).A 3.0T magnetic resonance imaging was used to evaluate the function of the glymphatic system.The mini-mental state examination(MMSE)was used to assess general cognitive function.The DTI-ALPS index of bilateral basal ganglia and the mean DTI-ALPS index was calculated.Further,the correlation between DTI-ALPS and clinical features was assessed.RESULTS The left-side,right-side,and mean DTI-ALPS index in the T2DM group were significantly lower than that in the NGM group.The right-side DTI-ALPS and mean DTI-ALPS index in the T2DM group were significantly lower than those in the prediabetes group.DTI-ALPS index lateralization was not observed.The MMSE score in the T2DM group was significantly lower than that in the NGM and prediabetes group.After controlling for sex,the left-side DTI-ALPS and mean DTI-ALPS index in the prediabetes group were positively correlated with 2-hour postprandial blood glucose level;the left-side DTI-ALPS index was negatively correlated with total cholesterol and low-density lipoprotein level.The right-side DTI-ALPS and mean DTI-ALPS index were negatively correlated with the glycosylated hemoglobin level and waist-to-hip ratio in the prediabetes group.The left-side,right-side,and mean DTI-ALPS index in the T2DM group were positively correlated with height.The left-side and mean DTIALPS index in the T2DM group were negatively correlated with high-density lipoprotein levels.CONCLUSION Cerebral glymphatic system dysfunction may mainly occur in the T2DM stage.Various clinical variables were found to affect the DTI-ALPS index in different glucose metabolism states.This study enhances our understanding of the pathophysiology of diabetic brain damage and provides some potential biological evidence for its early diagnosis.展开更多
Diffusion tensor imaging(DTI)provides a unique method to reveal the integrity of white matter microstructure noninvasively.Voxel-based analysis(VBA),which is a highly reproducible and user-independent technique,has be...Diffusion tensor imaging(DTI)provides a unique method to reveal the integrity of white matter microstructure noninvasively.Voxel-based analysis(VBA),which is a highly reproducible and user-independent technique,has been used to analyze DTI data in a number of studies.Fractional anisotropy(FA),which is derived from DTI,is the most frequently used parameter.The parameter setting during the DTI data preprocessing might affect the FA analysis results.However,there is no reliable evidence on how the parameters affect the results of FA analysis.This study sought to quantitatively investigate the factors that might affect the voxel-based analysis of FA;these include the interpolation during spatial normalization,smoothing kernel and statistical threshold.Because it is difficult to obtain the true information of the lesion in the patients,we simulated lesions on the healthy FA maps.The DTI data were obtained from 20 healthy subjects.The FA maps were calculated using DTIStudio.We randomly divided these FA maps into two groups.One was used as a model patient group,and the other was used as a normal control group.Simulated lesions were added to the model patient group by decreasing the FA intensities in a specified region by 5%–50%.The model patient group and the normal control group were compared by two-sample t test statistic analysis voxelby-voxel to detect the simulated lesions.We evaluated these factors by comparing the difference between the detected lesion through VBA and the simulated lesion.The result showed that the space normalization of FA image should use the trilinear interpolation,and the smoothing kernel should be 2–3 times the voxel size of spatially normalized FA image.For lesions with small intensity change,FWE correction must be cautiously used.This study provided an important reference to the analysis of FA with VBA method.展开更多
类淋巴系统(glymphatic system,GS)是近年出现的探究中枢神经系统疾病生理病理机制的新兴角度。研究证实沿血管周围间隙扩散张量分析(diffusion tensor image analysis along the perivascular space,DTI-ALPS)能够有效地评估中枢神经...类淋巴系统(glymphatic system,GS)是近年出现的探究中枢神经系统疾病生理病理机制的新兴角度。研究证实沿血管周围间隙扩散张量分析(diffusion tensor image analysis along the perivascular space,DTI-ALPS)能够有效地评估中枢神经系统疾病患者GS功能改变,尤其是在退行性中枢神经系统疾病,如癫痫、帕金森病、痴呆。本文就应用DTI-ALPS技术评估中枢神经系统疾病患者GS功能的研究现状作一综述,旨在为疾病的神经影像研究提供新方向。展开更多
目的通过文献计量学的方法分析2013—2023年血管周围间隙的研究现状、热点及前沿领域。方法在Web of Science核心合集数据库中检索2013年1月1日—2023年6月19日血管周围间隙相关英文论著。使用CiteSpace V6.3.R1软件分析文献的发文国家...目的通过文献计量学的方法分析2013—2023年血管周围间隙的研究现状、热点及前沿领域。方法在Web of Science核心合集数据库中检索2013年1月1日—2023年6月19日血管周围间隙相关英文论著。使用CiteSpace V6.3.R1软件分析文献的发文国家、研究机构、作者的合作网络,参考文献、第一作者、期刊的共被引网络,关键词的共现网络,关键词及参考文献共被引的突现情况;使用VOSviewer 1.6.15软件对关键词进行聚类分析。结果共纳入1549篇文献。2013—2023年的年发文量整体呈增长趋势。美国的发文量最多,其次为中国。发文量位列前3的研究机构分别是哈佛大学、麻省总医院和爱丁堡大学。合作网络分析发现国家间合作相对紧密,国内研究机构与其他研究机构合作较少。爱丁堡大学的Wardlaw Joanna M发文量最多。关键词共现图谱显示前10个高频关键词分别为小血管病、扩大的血管周围间隙、MRI、脑、Virchow-Robin间隙、阿尔茨海默病、痴呆、风险、卒中和类淋巴系统。关键词聚类分析发现脑小血管病、痴呆、MRI为当前研究热点,类淋巴系统为新兴的研究方向。关键词突现分析表明弥散成像从2021年至今备受关注。结论近10年血管周围间隙的研究热度逐年攀升。脑小血管病是主要的研究热点,类淋巴系统为新兴的研究方向,前沿领域为弥散张量成像等MRI技术。展开更多
目的应用沿血管周围间隙的扩散张量图像分析技术(DTI-ALPS)检测新诊断2型糖尿病(T2DM)患者脑胶质淋巴系统功能,探讨其与胰岛素抵抗指数(HOMA-IR)的相关性。方法选取徐州医科大学附属医院2023年4~6月临床确诊的新诊断的T2DM患者30例作为...目的应用沿血管周围间隙的扩散张量图像分析技术(DTI-ALPS)检测新诊断2型糖尿病(T2DM)患者脑胶质淋巴系统功能,探讨其与胰岛素抵抗指数(HOMA-IR)的相关性。方法选取徐州医科大学附属医院2023年4~6月临床确诊的新诊断的T2DM患者30例作为新诊断T2DM组,同时选取本院体检的与新诊断T2DM组年龄、性别相匹配的健康人30例为对照组。收集受试者临床检验指标(糖化血红蛋白、空腹血糖、空腹胰岛素水平),选取稳态模型作为评估胰岛素抵抗的指数,计算得出胰岛素抵抗HOMA-IR指数。采用3.0T核磁共振对60例受试者进行扫描,利用DTI计算ALPS指数,比较两组间的差异。采用Pearson相关性分析新诊断T2DM组HOMA-IR与ALPS指数之间的相关性。结果新诊断T2DM组空腹血糖、空腹胰岛素、糖化血红蛋白、HOMA-IR高于正常对照组(P<0.05)。新诊断T2DM组ALPS指数下降(1.50±0.22 vs 1.31±0.18,P<0.001),与HOMA-IR呈负相关(r=-0.622,P<0.001)。结论DTI-ALPS技术可用于评估新诊断T2DM患者的胶质淋巴系统功能,其功能的下降与胰岛素抵抗密切相关。展开更多
目的探究女性乳腺癌患者术前新辅助化疗后脑静息态功能和类淋巴功能变化及其之间的相关性。方法40名健康女性被试及80名女性乳腺癌患者被纳入本次研究,乳腺癌患者均进行术前新辅助化疗。应用MMSE、DSST和FACT-CogPCI评分评估被试认知功...目的探究女性乳腺癌患者术前新辅助化疗后脑静息态功能和类淋巴功能变化及其之间的相关性。方法40名健康女性被试及80名女性乳腺癌患者被纳入本次研究,乳腺癌患者均进行术前新辅助化疗。应用MMSE、DSST和FACT-CogPCI评分评估被试认知功能。应用rsfMRI获取反映大脑功能活动的ALFF指标。应用DTI-ALPS技术获取反映脑类淋巴功能的ALPS指数。分析乳腺癌患者化疗前后ALFF及ALPS变化,分析各指标与认知评分之间的相关性,并分析ALFF与ALPS之间的相关性情况。结果乳腺癌患者化疗后MMSE、DSST及FACT-CogPCI评分均减低(P<0.05)。化疗后,左侧颞极中部、左侧丘脑腹外侧核及右侧顶后中回团块ALFF值减低,双侧颞叶、枕叶及顶叶多个脑区的ALFF值与FACTCogPCI评分呈正相关(pFDR-C<0.001)。化疗后ALPS指数相比正常被试增高(1.42±0.29 vs 1.56±0.24,P=0.011),同时ALPS指数与FACT-CogPCI评分呈正相关(r=0.241,P=0.04)。与此同时化疗后左侧舌状回ALFF值与ALPS指数呈正相关(r=0.69,P<0.001)。结论研究结果提示,大脑功能活动和类淋巴引流均参与化疗后认知功能改变的过程,同时两者存在相关性。展开更多
文摘To attain the volumetric information of the optic radiation in normal human brains, we per- formed diffusion tensor imaging examination in 13 healthy volunteers. Simultaneously, we used a brain normalization method to reduce individual brain variation and increase the accuracy of volumetric information analysis. In addition, tractography-based group mapping method was also used to investigate the probability and distribution of the optic radiation pathways. Our results showed that the measured optic radiation fiber tract volume was a range of about 0.16% and that the fractional anisotropy value was about 0.53. Moreover, the optic radiation probability fiber pathway that was determined with diffusion tensor tractography-based group mapping was able to detect the location relatively accurately. We believe that our methods and results are help- ful in the study of optic radiation fiber tract information.
文摘Purpose: To determine the total direct costs (fixed and variable costs) of diffusion tensor imaging (DTI) and MR tractography reconstruction of the brain. Materials and Methods: The direct fixed and variable costs of DTI with MR tractography were determined prospectively with time and motion analysis in a 1.5-Tesla MR scanner using 15 encoding directions. Seventeen patients with seizure disorders, 9 males & 8 females, with mean age of 13 years (age range 2 - 33 years) were studied. Total direct costs were calculated from all direct fixed and variable costs. Sensitivity analyses between 1.5 versus a 3-Tesla MR system, and 15 versus 32 encoding directions were done. Results: The total direct costs of DTI and MR tractography for a 1.5-T system with 15 encoding directions were US $97. Variable cost was $76.80 and fixed cost was $20.20. Total direct costs for a 3-T system with 15 directions decreased to US $94.5 because of the shorter scan time despite the higher cost of the 3-T system. The most costly component of the direct cost was post-processing analysis at US $46.00. Conclusion: DTI with MR tractography has important total direct costs with variable costs higher than the fixed costs. The post processing variable cost is the most expensive component. Developing more accurate automated post-processing software for DTI and MR tractography is important to decrease this variable labor cost. Given the added value of DTI-MR tractography and the costs involved reimbursement codes should be considered.
文摘BACKGROUND： Previous studies regarding primary progressive aphasia （PPA） have focused on progressive, non-fluent aphasia. Little information is available with regard to the use of diffusion tensor imaging compared with conventional magnetic resonance imaging for the detection of subtle structural abnormalities. OBJECTIVE： To investigate and localize brain abnormalities in a Chinese patient with semantic dementia. DESIGN, TIME AND SETTING： A concurrent, non-randomized, case-controlled, neuroimaging, clinical trial was performed at the Department of Radiology, West China Hospital of Sichuan University in March 2009. PARTICIPANTS： One 75-year-old male patient, who was diagnosed with semantic dementia, and 21 age- and gender-matched healthy volunteers were recruited for the study. METHODS： Diffusion tensor imaging was used to determine mean diffusion （MD） and fractional anisotropy （FA） in the brains of the patient and the 21 healthy subjects. Voxel-based analysis of MD and FA values was performed using statistical parametric mapping. MAIN OUTCOME MEASURES： MD and FA value maps differences between patient and controls. RESULTS： MD was significantly increased in both cerebra, but was predominant on the left side and expanded to outside of the language-related region. Reduced MD was not detected in any of the brains. FA was shown to be decreased in the corpus callosum, but was increased in the basal ganglia. CONCLUSION： The present study provided clear in vivo magnetic imaging evidence of diffuse brain involvement in semantic dementia. Increases in MD were greater than in FA when brain diffusion alterations were detected, which suggested that MD could be a better marker of disease progression.
基金supported by the National Natural Science Foundation of China, No. 81171318Shaanxi Provincial Scientific Research Project, No. 2012K13-02-24
文摘Proton magnetic resonance spectroscopy and diffusion tensor imaging are non-invasive techniques used to detect metabolites and water diffusion in vivo. Previous studies have confirmed a positive correlation of individual fractional anisotropy values with N-acetylaspartate/creatine and N-acetylaspartate/choline ratios in tumors, edema, and normal white matter. This study divided the brain parenchyma into tumor, pedtumoral edema, and normal-appearing white matter according to MRI data, and analyzed the correlation of metabolites with water molecular diffusion. Results demonstrated that in normal-appearing white matter, N-acetylaspartate/creatine ratios were positively correlated with fractional anisotropy values, negatively correlated with radial diffusivities, and positively correlated with maximum eigenvalues. Maximum eigenvalues and radial diffusivities in peritumoral edema showed a negative correlation with choline, N-acetylaspartate, and creatine. Radial diffusivities in tumor demonstrated a negative correlation with choline. These data suggest that the relationship between metabolism and structure is markedly changed from normal white matter to peritumoral edema and tumor. Neural metabolism in the peritumoral edema area decreased with expanding extracellular space. The normal relationship of neural function and microstructure disappeared in the tumor region.
文摘类淋巴系统(glymphatic system,GS)是大脑中废物清除的途径,其功能受损可以通过沿血管周围间隙扩散张量成像分析(diffusion tensor imaging analysis along the perivascular space,DTI-ALPS)进行评估。目前,DTI-ALPS作为一种非侵入性方法已被广泛用于评估神经系统疾病中的GS功能改变,它在评估神经系统疾病的病程进展、认知障碍及预测预后等方面发挥了举足轻重的作用。本文就GS、DTI-ALPS方法与应用优势及其在神经系统疾病中的应用进行综述,旨在为神经系统疾病的病程进展、预测影响预后因素以及临床治疗疗效方面提供一定的参考。
文摘Background Diffusion tensor imaging （DTI） permits quantitative examination within the pyramidal tract （PT） by measuring fractional anisotropy （FA）. To the best of our knowledge, the inter-variability measures of FA along the PT remain unexplained. A clear understanding of these reference values would help radiologists and neuroscientists to understand normality as well as to detect early pathophysiologic changes of brain diseases. The aim of our study was to calculate the variability of the FA at eleven anatomical landmarks along the PT and the influences of gender and cerebral hemisphere in these measurements in a sample of young, healthy volunteers. Methods A retrospective, cross-sectional study was performed in twenty-three right-handed healthy volunteers who underwent magnetic resonance evaluation of the brain. Mean FA values from eleven anatomical landmarks across the PT （at centrum semiovale, corona radiata, posterior limb of internal capsule （PLIC）, mesencephalon, pons, and medulla oblongata） were evaluated using split-plot factorial analysis of variance （ANOVA）. Results We found a significant interaction effect between anatomical landmark and cerebral hemisphere （F （10, 32）=4.516, P=0.001; Wilks＇ Lambda 0.415, with a large effect size （partial η2=0.585））. The influence of gender and age was non-significant. On average, the midbrain and PLIC FA values were higher than pons and medulla oblongata values; centrum semiovale measurements were higher than those of the corona radiata but lower than PLIC. Conclusions There is a normal variability of FA measurements along PT in healthy individuals, which is influenced by regions of interest location （anatomical landmarks） and cerebral hemisphere. FA measurements should be reported for comparing same-side and same-landmark PT to help avoid comparisons with the contralateral PT; ideally, normative values should exist for a clinically significant age group. A standardized package of selected DTI processing tools would allow DTI processing to be routinely performed in clinical settings.
文摘BACKGROUND Dysfunction of the glymphatic system in the brain in different stages of altered glucose metabolism and its influencing factors are not well characterized.AIM To investigate the function of the glymphatic system and its clinical correlates in patients with different glucose metabolism states,the present study employed diffusion tensor imaging along the perivascular space(DTI-ALPS)index.METHODS Sample size was calculated using the pwr package in R software.This crosssectional study enrolled 22 patients with normal glucose metabolism(NGM),20 patients with prediabetes,and 22 patients with type 2 diabetes mellitus(T2DM).A 3.0T magnetic resonance imaging was used to evaluate the function of the glymphatic system.The mini-mental state examination(MMSE)was used to assess general cognitive function.The DTI-ALPS index of bilateral basal ganglia and the mean DTI-ALPS index was calculated.Further,the correlation between DTI-ALPS and clinical features was assessed.RESULTS The left-side,right-side,and mean DTI-ALPS index in the T2DM group were significantly lower than that in the NGM group.The right-side DTI-ALPS and mean DTI-ALPS index in the T2DM group were significantly lower than those in the prediabetes group.DTI-ALPS index lateralization was not observed.The MMSE score in the T2DM group was significantly lower than that in the NGM and prediabetes group.After controlling for sex,the left-side DTI-ALPS and mean DTI-ALPS index in the prediabetes group were positively correlated with 2-hour postprandial blood glucose level;the left-side DTI-ALPS index was negatively correlated with total cholesterol and low-density lipoprotein level.The right-side DTI-ALPS and mean DTI-ALPS index were negatively correlated with the glycosylated hemoglobin level and waist-to-hip ratio in the prediabetes group.The left-side,right-side,and mean DTI-ALPS index in the T2DM group were positively correlated with height.The left-side and mean DTIALPS index in the T2DM group were negatively correlated with high-density lipoprotein levels.CONCLUSION Cerebral glymphatic system dysfunction may mainly occur in the T2DM stage.Various clinical variables were found to affect the DTI-ALPS index in different glucose metabolism states.This study enhances our understanding of the pathophysiology of diabetic brain damage and provides some potential biological evidence for its early diagnosis.
基金supported by the National Natural Science Foundation of China(81201147,91232713)the XieJialin Foundation of IHEP(3546370U2)foundation of IHEP(Y2515580U1)
文摘Diffusion tensor imaging(DTI)provides a unique method to reveal the integrity of white matter microstructure noninvasively.Voxel-based analysis(VBA),which is a highly reproducible and user-independent technique,has been used to analyze DTI data in a number of studies.Fractional anisotropy(FA),which is derived from DTI,is the most frequently used parameter.The parameter setting during the DTI data preprocessing might affect the FA analysis results.However,there is no reliable evidence on how the parameters affect the results of FA analysis.This study sought to quantitatively investigate the factors that might affect the voxel-based analysis of FA;these include the interpolation during spatial normalization,smoothing kernel and statistical threshold.Because it is difficult to obtain the true information of the lesion in the patients,we simulated lesions on the healthy FA maps.The DTI data were obtained from 20 healthy subjects.The FA maps were calculated using DTIStudio.We randomly divided these FA maps into two groups.One was used as a model patient group,and the other was used as a normal control group.Simulated lesions were added to the model patient group by decreasing the FA intensities in a specified region by 5%–50%.The model patient group and the normal control group were compared by two-sample t test statistic analysis voxelby-voxel to detect the simulated lesions.We evaluated these factors by comparing the difference between the detected lesion through VBA and the simulated lesion.The result showed that the space normalization of FA image should use the trilinear interpolation,and the smoothing kernel should be 2–3 times the voxel size of spatially normalized FA image.For lesions with small intensity change,FWE correction must be cautiously used.This study provided an important reference to the analysis of FA with VBA method.
文摘类淋巴系统(glymphatic system,GS)是近年出现的探究中枢神经系统疾病生理病理机制的新兴角度。研究证实沿血管周围间隙扩散张量分析(diffusion tensor image analysis along the perivascular space,DTI-ALPS)能够有效地评估中枢神经系统疾病患者GS功能改变,尤其是在退行性中枢神经系统疾病,如癫痫、帕金森病、痴呆。本文就应用DTI-ALPS技术评估中枢神经系统疾病患者GS功能的研究现状作一综述,旨在为疾病的神经影像研究提供新方向。
文摘目的应用沿血管周围间隙的扩散张量图像分析技术(DTI-ALPS)检测新诊断2型糖尿病(T2DM)患者脑胶质淋巴系统功能,探讨其与胰岛素抵抗指数(HOMA-IR)的相关性。方法选取徐州医科大学附属医院2023年4~6月临床确诊的新诊断的T2DM患者30例作为新诊断T2DM组,同时选取本院体检的与新诊断T2DM组年龄、性别相匹配的健康人30例为对照组。收集受试者临床检验指标(糖化血红蛋白、空腹血糖、空腹胰岛素水平),选取稳态模型作为评估胰岛素抵抗的指数,计算得出胰岛素抵抗HOMA-IR指数。采用3.0T核磁共振对60例受试者进行扫描,利用DTI计算ALPS指数,比较两组间的差异。采用Pearson相关性分析新诊断T2DM组HOMA-IR与ALPS指数之间的相关性。结果新诊断T2DM组空腹血糖、空腹胰岛素、糖化血红蛋白、HOMA-IR高于正常对照组(P<0.05)。新诊断T2DM组ALPS指数下降(1.50±0.22 vs 1.31±0.18,P<0.001),与HOMA-IR呈负相关(r=-0.622,P<0.001)。结论DTI-ALPS技术可用于评估新诊断T2DM患者的胶质淋巴系统功能,其功能的下降与胰岛素抵抗密切相关。
文摘目的探究女性乳腺癌患者术前新辅助化疗后脑静息态功能和类淋巴功能变化及其之间的相关性。方法40名健康女性被试及80名女性乳腺癌患者被纳入本次研究,乳腺癌患者均进行术前新辅助化疗。应用MMSE、DSST和FACT-CogPCI评分评估被试认知功能。应用rsfMRI获取反映大脑功能活动的ALFF指标。应用DTI-ALPS技术获取反映脑类淋巴功能的ALPS指数。分析乳腺癌患者化疗前后ALFF及ALPS变化,分析各指标与认知评分之间的相关性,并分析ALFF与ALPS之间的相关性情况。结果乳腺癌患者化疗后MMSE、DSST及FACT-CogPCI评分均减低(P<0.05)。化疗后,左侧颞极中部、左侧丘脑腹外侧核及右侧顶后中回团块ALFF值减低,双侧颞叶、枕叶及顶叶多个脑区的ALFF值与FACTCogPCI评分呈正相关(pFDR-C<0.001)。化疗后ALPS指数相比正常被试增高(1.42±0.29 vs 1.56±0.24,P=0.011),同时ALPS指数与FACT-CogPCI评分呈正相关(r=0.241,P=0.04)。与此同时化疗后左侧舌状回ALFF值与ALPS指数呈正相关(r=0.69,P<0.001)。结论研究结果提示,大脑功能活动和类淋巴引流均参与化疗后认知功能改变的过程,同时两者存在相关性。
