Many studies have observed atrophy and abnormal diffusion within the CC in MS. However, few studi... more Many studies have observed atrophy and abnormal diffusion within the CC in MS. However, few studies have addressed whether such abnormalities appear at the earliest stage of MS, especially in CIS. In this study, we aimed to investigate the CC integrity and patterns of CC abnormalities in CIS with diffusion tensor group tractography.
Objective: The purposes of our study were to employ diffusion tensor imaging (DTI)-based histogra... more Objective: The purposes of our study were to employ diffusion tensor imaging (DTI)-based histogram analysis to determine the presence of occult damage in clinically isolated syndrome (CIS), to compare its severity with relapsing-remitting multiple sclerosis (RRMS), and to determine correlations between DTI histogram measures and clinical and MRI indices in these two diseases. Materials and methods: DTI scans were performed in 19 CIS and 19 RRMS patients and 19 matched healthy volunteers. Histogram analyses of mean diffusivity and fractional anisotropy were performed in normal-appearing brain tissue (NABT), normal-appearing white matter (NAWM) and gray matter (NAGM). Correlations were analyzed between these measures and expanded disability status scale (EDSS) scores, T 2 WI lesion volumes (LV) and normalized brain tissue volumes (NBTV) in CIS and RRMS patients. Results: Significant differences were found among CIS, RRMS and control groups in the NBTV and most of the DTI histogram measures of the NABT, NAWM and NAGM. In CIS patients, some DTI histogram measures showed significant correlations with LV and NBTV, but none of them with EDSS. In RRMS patients, however, some DTI histogram measures were significantly correlated with LV, NBTV and EDSS. Conclusion: Occult damage occurs in both NAGM and NAWM in CIS, but the severity is milder than that in RRMS. In CIS and RRMS, the occult damage might be related to both T2 lesion load and brain tissue atrophy. Some DTI histogram measures might be useful for assessing the disease progression in RRMS patients.
Background: Abnormal macrostructural brain abnormalities in both gray matter and white matter hav... more Background: Abnormal macrostructural brain abnormalities in both gray matter and white matter have been reported in cigarette smokers. However, less is known about white matter microstructure in heavy cigarette smokers. In this study, we used diffusion tensor imaging (DTI) to investigate the integrity of the white matter microstructure in heavy smokers. Methods: Thirty-four heavy smokers and 34 non-smokers participated in this study. Whole brain analysis of fractional anisotropy (FA) was performed using tract-based spatial statistics (TBSS) to detect abnormal white matter regions between groups. Volume-of-interest (VOI) analysis was used to investigate changes in diffusivity indices in the regions showing FA abnormalities. Multiple regression analysis was applied to assess the relationships between diffusion indices and smoking-related variables in heavy smokers. Results: Compared with non-smokers, heavy smokers had lower FA in the left anterior (i.e., the genu and rostral body) corpus callosum while exhibiting no areas of higher FA. In the affected region, FA reduction was accompanied by a significantly decreased axial diffusivity and increased radial diffusivity, which suggests that axonal damage and disrupted myelin integrity may be associated with the degraded white matter integrity in heavy smokers. Moreover, significant positive correlations were found between both radial diffusivity and mean diffusivity and the duration of regular smoking. Conclusions: Our findings suggest that heavy smokers demonstrate abnormal integrity of the white matter microstructure in the anterior corpus callosum, which is related to the duration of regular smoking. In addition, our study may increase the understanding of the neurobiological basis of chronic cigarette smoking.
Objective: In bipolar disorder, white matter abnormalities have been reported with region-ofinter... more Objective: In bipolar disorder, white matter abnormalities have been reported with region-ofinterest and voxel-based methods; however, deficits in specific white matter tracts cannot be localized by these methods. Therefore, in this study, we aimed to investigate the white matter tracts that mediate connectivity of the frontal cortex using diffusion tensor imaging (DTI) tractography. Methods: Eighteen patients with bipolar disorder and sixteen age-and gender-matched healthy subjects underwent DTI examinations. Frontal cortex white matter tracts, including the anterior thalamic radiation (ATR), uncinate fasciculus (UF), superior longitudinal fasciculus (SLF), cingulum, and inferior fronto-occipital fasciculus (IFO) were reconstructed by DTI tractography, and we calculated the mean fractional anisotropy (FA) for each fiber tract. The values were compared between groups by repeated measures analysis of variance with age and gender as covariates, which allowed us to investigate significant differences between the tracts. Results: When compared with healthy controls, the patients with bipolar disorder showed significantly decreased FA in the ATR and UF, and a trend towards lower FA in the SLF and cingulum. However, there were no FA differences between groups in the IFO. Conclusions: Our study indicates that bipolar patients show abnormalities within white matter tracts connecting the frontal cortex with the temporal and parietal cortices and the frontosubcortical circuits. These findings suggest that alterations in the connectivity of white matter tracts in the frontal cortex might contribute to the neuropathology of bipolar disorder.
Background: Studies were carried out to detect brain tissue damage in patients with vascular cogn... more Background: Studies were carried out to detect brain tissue damage in patients with vascular cognitive impairment (VCI) using diffusion tensor imaging (DTI) histogram analysis, and to determine the correlations between DTI histogram-derived measures and Mini-Mental State Examination (MMSE) scores. Methods: Conventional MRI and DTI scans were performed on 19 patients with VCI, 19 age-and sex-matched post-stroke patients without cognitive impairment (stroke group) and 19 cognitively normal subjects (CN group). Histograms of the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of the whole brain were analyzed. Results: Analysis showed that the patterns of the whole brain ADC and FA histograms of the VCI group differed from those of the stroke and CN groups. Compared with those of the two control groups, the mean FA value was significantly lower and the FA histogram peak height was higher in the VCI group. However, the patterns of the whole brain ADC and FA histograms in the stroke group were similar to those of the CN group, and there were no significant differences in any of the DTI histogram-derived measures between these two groups. The mean FA value, the FA histogram peak height, and the FA histogram peak location in VCI patients correlated with the MMSE scores. Conclusions: Our findings suggest that VCI leads to abnormal diffusion in brain tissue, and that DTI histogram-derived measures might be used to monitor the severity of cognitive impairment in this disease.
Background: This study aims to investigate brain gray matter density (GMD) changes in adolescents... more Background: This study aims to investigate brain gray matter density (GMD) changes in adolescents with Internet addiction (IA) using voxel-based morphometry (VBM) analysis on high-resolution T1-weighted structural magnetic resonance images. Methods: Eighteen IA adolescents and 15 age-and gender-matched healthy controls took part in this study. High-resolution T1-weighted magnetic resonance imaging scans were performed on the two groups. VBM analysis was used to compare the GMD between the two groups. Results: Compared with healthy controls, IA adolescents had lower GMD in the left anterior cingulate cortex, left posterior cingulate cortex, left insula, and left lingual gyrus. Conclusions: Our findings suggested that brain structural changes were present in IA adolescents, and this finding may provide a new insight into the pathogenesis of IA.
In this paper, we presented an indirect approach which automatically separates the splenium of co... more In this paper, we presented an indirect approach which automatically separates the splenium of corpus callosum on mid-sagittal slice of diffusion tensor image (DTI). The callosal fibers were first extracted to decide the corresponding location in the 2D splenium. Using some specific features determined from their geometric properties, the fibers crossing the splenium were clustered into three bundles, which interconnect bilateral temporal, parietal and occipital lobes, respectively. The sub-regions of the splenium were then demarcated by mapping the clusters to the splenium. Similar distribution pattern of these three sub-regions were obtained by applying our method to two real data sets, which indicated the potential applicability of this approach for the further studies of the splenium.
In this article, we present some advances on medical imaging and computing at the National Labora... more In this article, we present some advances on medical imaging and computing at the National Laboratory of Pattern Recognition (NLPR) in the Chinese Academy of Sciences. The first part is computational neuroanatomy. Several novel methods on segmentations of brain tissue and anatomical substructures, brain image registration, and shape analysis are presented. The second part consists of brain connectivity, which includes anatomical connectivity based on diffusion tensor imaging (DTI), functional and effective connectivity with functional magnetic resonance imaging (fMRI). It focuses on abnormal patterns of brain connectivity of patients with various brain disorders compared with matched normal controls. Finally, some prospects and future research directions in this field are also given.
Many studies have reported abnormal changes in relapsing-remitting multiple sclerosis (RRMS) by h... more Many studies have reported abnormal changes in relapsing-remitting multiple sclerosis (RRMS) by histogram and region-of-interest-based methods by using diffusion tenor imaging. However, there are few studies on specific white matter fiber tracts of RRMS. Our study sought to use diffusion tensor tractography-based group mapping to investigate the presence of abnormal diffusion in the normal-appearing pyramidal tract (PYT) of RRMS and its possible mechanism. A PYT probability map was first constructed from data on 20 healthy patients based on the deterministic-based tractography method. The PYT probability map was then applied to 29 RRMS patients to calculate diffusion indices of the PYT. In this study, 4 quantitative indices-fractional anisotropy (FA), directionally averaged diffusion coefficient (D(av)), axial diffusion coefficient (lambda(1)), and radial diffusion coefficient (lambda(23))-were used to characterize the abnormal diffusion. Compared with healthy controls, RRMS patient...
BACKGROUND AND PURPOSE: Normal-appearing brain tissue (NABT) damage was established in multiple s... more BACKGROUND AND PURPOSE: Normal-appearing brain tissue (NABT) damage was established in multiple sclerosis by histology, MR spectroscopy, magnetization transfer imaging and diffusion tensor imaging (DTI). However, whether this phenomenon can be detected in relapsing neuromyelitis optica (RNMO) remains unclear. The aim of this study was to use DTI to investigate the presence of NABT damage in RNMO patients and its
Glaucoma; Lateral geniculate nucleus; Magnetic resonance imaging Summary Purpose: To investigate ... more Glaucoma; Lateral geniculate nucleus; Magnetic resonance imaging Summary Purpose: To investigate the relationship between morphological changes in the lateral geniculate nucleus (LGN), as measured by magnetic resonance imaging (MRI), and damage to the optic disc in primary open-angle glaucoma (POAG) patients. Methods: A total of 23 patients with POAG and 23 age-and gender-matched non-glaucomatous subjects were enrolled. Every patient had structural damage to the optic disc. Cup-to-disc ratio (CDR) and retinal nerve fiber layer thickness (RNFLT) were measured, and 3.0-Tesla MRI examinations performed. Bilateral LGNs were identified and manually extracted, and their maximum heights and volumes compared with the clinical damage to the optic disc. Results: In POAG patients, morphological changes in LGNs and RNFLT were consistently varied (P < 0.05), while a negative correlation between LGN measurements and CDR was observed (P < 0.05).
Background: To investigate nerve fibre damage of the visual pathway in patients with primary open... more Background: To investigate nerve fibre damage of the visual pathway in patients with primary open-angle glaucoma using tract-based spatial statistical analysis of diffusion tensor imaging and correlate these measures with the clinical severity of glaucoma.
Diabetes mellitus affects the brain. Both type 1 and type 2 diabetic patients are associated with... more Diabetes mellitus affects the brain. Both type 1 and type 2 diabetic patients are associated with white matter (WM) damage observable to diffusion tensor imaging (DTI). The underlying histopathological mechanisms, however, are poorly understood. The objectives of this study are 1) to determine whether streptozotocin (STZ)-induced type 1 diabetes is associated with WM damage observable to DTI; and 2) to understand the pathophysiological aspects underlying STZ-induced brain injuries. Male Sprague-Dawley rats received a single intraperitoneal injection of STZ (62 mg/kg). DTI was used to assess brain abnormalities at 4 weeks after induction, combined with histological assessments and ultrastructural analysis. Compared to controls, the STZ-induced rats showed significantly reduced fractional anisotropy (FA) in the motor/somatosensory cortex and striatum. Histologically, the cortex and striatum of the diabetic animals are characterized by demyelination and axonal degradation. In conclusio...
Glaucoma; Lateral geniculate nucleus; Magnetic resonance imaging Summary Purpose: To investigate ... more Glaucoma; Lateral geniculate nucleus; Magnetic resonance imaging Summary Purpose: To investigate the relationship between morphological changes in the lateral geniculate nucleus (LGN), as measured by magnetic resonance imaging (MRI), and damage to the optic disc in primary open-angle glaucoma (POAG) patients. Methods: A total of 23 patients with POAG and 23 age-and gender-matched non-glaucomatous subjects were enrolled. Every patient had structural damage to the optic disc. Cup-to-disc ratio (CDR) and retinal nerve fiber layer thickness (RNFLT) were measured, and 3.0-Tesla MRI examinations performed. Bilateral LGNs were identified and manually extracted, and their maximum heights and volumes compared with the clinical damage to the optic disc. Results: In POAG patients, morphological changes in LGNs and RNFLT were consistently varied (P < 0.05), while a negative correlation between LGN measurements and CDR was observed (P < 0.05).
To prospectively evaluate diffusion indexes of the corticospinal tract (CST), corpus callosum (CC... more To prospectively evaluate diffusion indexes of the corticospinal tract (CST), corpus callosum (CC), optic radiation (OR), and cingulum in patients with neuromyelitis optica (NMO) without visible lesions in the brain.
Previous studies demonstrated that primary open angle glaucoma (POAG) is associated with abnormal... more Previous studies demonstrated that primary open angle glaucoma (POAG) is associated with abnormal brain structure; however, little is known about the changes in the local synchronization of spontaneous activity. The main objective of this study was to investigate spontaneous brain activity in patients with POAG using regional homogeneity (ReHo) analysis based on resting state functional magnetic resonance imaging (rs-fMRI). Thirty-nine POAG patients and forty-one age- and gender- matched healthy controls were finally included in the study. ReHo values were used to evaluate spontaneous brain activity and whole brain voxel-wise analysis of ReHo was carried out to detect differences by region in spontaneous brain activity between groups. Compared to controls, POAG patients showed increased ReHo in the right dorsal anterior cingulated cortex, the bilateral medial frontal gyrus and the right cerebellar anterior lobe, and decreased ReHo in the bilateral calcarine, bilateral precuneus gryus, bilateral pre/postcentral gyrus, left inferior parietal lobule and left cerebellum posterior lobe. A multiple linear regression analysis was performed to explore the relationships between clinical measures and ReHo by region showed significant group differences in the POAG group. Negative correlations were found between age and the ReHo values of the superior frontal gyrus (r = -0.323, p = 0.045), left calcarine (r = -0.357, p = 0.026) and inferior parietal lobule (r = -0.362, p = 0.024). A negative correlation was found between the ReHo values of the left precuneus and the cumulative mean defect (r = -0.400, p = 0.012). POAG was associated with abnormal brain spontaneous activity in some brain regions and such changed regional activity may be associated with clinical parameters. Spontaneous brain activity may play a role in POAG initiation and progression.
Seed-based cross-correlation analysis (sCCA) and independent component analysis have been widely ... more Seed-based cross-correlation analysis (sCCA) and independent component analysis have been widely employed to extract functional networks from the resting state functional magnetic resonance imaging data. However, the results of sCCA, in terms of both connectivity strength and network topology, can be sensitive to seed selection variations. ICA avoids the potential problems due to seed selection, but choosing which component(s) to represent the network of interest could be subjective and problematic. In this study, we proposed a seed-based iterative cross-correlation analysis (siCCA) method for resting state brain network analysis. The method was applied to extract default mode network (DMN) and stable task control network (STCN) in two independent datasets acquired from normal adults. Compared with the networks obtained by traditional sCCA and ICA, the resting state networks produced by siCCA were found to be highly stable and independent on seed selection. siCCA was used to analyze DMN in first-episode major depressive disorder (MDD) patients. It was found that, in the MDD patients, the volume of DMN negatively correlated with the patients&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; social disability screening schedule scores.
Background: Internet addiction disorder (IAD) is currently becoming a serious mental health issue... more Background: Internet addiction disorder (IAD) is currently becoming a serious mental health issue around the globe. Previous studies regarding IAD were mainly focused on associated psychological examinations. However, there are few studies on brain structure and function about IAD. In this study, we used diffusion tensor imaging (DTI) to investigate white matter integrity in adolescents with IAD.
Many studies have observed atrophy and abnormal diffusion within the CC in MS. However, few studi... more Many studies have observed atrophy and abnormal diffusion within the CC in MS. However, few studies have addressed whether such abnormalities appear at the earliest stage of MS, especially in CIS. In this study, we aimed to investigate the CC integrity and patterns of CC abnormalities in CIS with diffusion tensor group tractography.
Objective: The purposes of our study were to employ diffusion tensor imaging (DTI)-based histogra... more Objective: The purposes of our study were to employ diffusion tensor imaging (DTI)-based histogram analysis to determine the presence of occult damage in clinically isolated syndrome (CIS), to compare its severity with relapsing-remitting multiple sclerosis (RRMS), and to determine correlations between DTI histogram measures and clinical and MRI indices in these two diseases. Materials and methods: DTI scans were performed in 19 CIS and 19 RRMS patients and 19 matched healthy volunteers. Histogram analyses of mean diffusivity and fractional anisotropy were performed in normal-appearing brain tissue (NABT), normal-appearing white matter (NAWM) and gray matter (NAGM). Correlations were analyzed between these measures and expanded disability status scale (EDSS) scores, T 2 WI lesion volumes (LV) and normalized brain tissue volumes (NBTV) in CIS and RRMS patients. Results: Significant differences were found among CIS, RRMS and control groups in the NBTV and most of the DTI histogram measures of the NABT, NAWM and NAGM. In CIS patients, some DTI histogram measures showed significant correlations with LV and NBTV, but none of them with EDSS. In RRMS patients, however, some DTI histogram measures were significantly correlated with LV, NBTV and EDSS. Conclusion: Occult damage occurs in both NAGM and NAWM in CIS, but the severity is milder than that in RRMS. In CIS and RRMS, the occult damage might be related to both T2 lesion load and brain tissue atrophy. Some DTI histogram measures might be useful for assessing the disease progression in RRMS patients.
Background: Abnormal macrostructural brain abnormalities in both gray matter and white matter hav... more Background: Abnormal macrostructural brain abnormalities in both gray matter and white matter have been reported in cigarette smokers. However, less is known about white matter microstructure in heavy cigarette smokers. In this study, we used diffusion tensor imaging (DTI) to investigate the integrity of the white matter microstructure in heavy smokers. Methods: Thirty-four heavy smokers and 34 non-smokers participated in this study. Whole brain analysis of fractional anisotropy (FA) was performed using tract-based spatial statistics (TBSS) to detect abnormal white matter regions between groups. Volume-of-interest (VOI) analysis was used to investigate changes in diffusivity indices in the regions showing FA abnormalities. Multiple regression analysis was applied to assess the relationships between diffusion indices and smoking-related variables in heavy smokers. Results: Compared with non-smokers, heavy smokers had lower FA in the left anterior (i.e., the genu and rostral body) corpus callosum while exhibiting no areas of higher FA. In the affected region, FA reduction was accompanied by a significantly decreased axial diffusivity and increased radial diffusivity, which suggests that axonal damage and disrupted myelin integrity may be associated with the degraded white matter integrity in heavy smokers. Moreover, significant positive correlations were found between both radial diffusivity and mean diffusivity and the duration of regular smoking. Conclusions: Our findings suggest that heavy smokers demonstrate abnormal integrity of the white matter microstructure in the anterior corpus callosum, which is related to the duration of regular smoking. In addition, our study may increase the understanding of the neurobiological basis of chronic cigarette smoking.
Objective: In bipolar disorder, white matter abnormalities have been reported with region-ofinter... more Objective: In bipolar disorder, white matter abnormalities have been reported with region-ofinterest and voxel-based methods; however, deficits in specific white matter tracts cannot be localized by these methods. Therefore, in this study, we aimed to investigate the white matter tracts that mediate connectivity of the frontal cortex using diffusion tensor imaging (DTI) tractography. Methods: Eighteen patients with bipolar disorder and sixteen age-and gender-matched healthy subjects underwent DTI examinations. Frontal cortex white matter tracts, including the anterior thalamic radiation (ATR), uncinate fasciculus (UF), superior longitudinal fasciculus (SLF), cingulum, and inferior fronto-occipital fasciculus (IFO) were reconstructed by DTI tractography, and we calculated the mean fractional anisotropy (FA) for each fiber tract. The values were compared between groups by repeated measures analysis of variance with age and gender as covariates, which allowed us to investigate significant differences between the tracts. Results: When compared with healthy controls, the patients with bipolar disorder showed significantly decreased FA in the ATR and UF, and a trend towards lower FA in the SLF and cingulum. However, there were no FA differences between groups in the IFO. Conclusions: Our study indicates that bipolar patients show abnormalities within white matter tracts connecting the frontal cortex with the temporal and parietal cortices and the frontosubcortical circuits. These findings suggest that alterations in the connectivity of white matter tracts in the frontal cortex might contribute to the neuropathology of bipolar disorder.
Background: Studies were carried out to detect brain tissue damage in patients with vascular cogn... more Background: Studies were carried out to detect brain tissue damage in patients with vascular cognitive impairment (VCI) using diffusion tensor imaging (DTI) histogram analysis, and to determine the correlations between DTI histogram-derived measures and Mini-Mental State Examination (MMSE) scores. Methods: Conventional MRI and DTI scans were performed on 19 patients with VCI, 19 age-and sex-matched post-stroke patients without cognitive impairment (stroke group) and 19 cognitively normal subjects (CN group). Histograms of the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of the whole brain were analyzed. Results: Analysis showed that the patterns of the whole brain ADC and FA histograms of the VCI group differed from those of the stroke and CN groups. Compared with those of the two control groups, the mean FA value was significantly lower and the FA histogram peak height was higher in the VCI group. However, the patterns of the whole brain ADC and FA histograms in the stroke group were similar to those of the CN group, and there were no significant differences in any of the DTI histogram-derived measures between these two groups. The mean FA value, the FA histogram peak height, and the FA histogram peak location in VCI patients correlated with the MMSE scores. Conclusions: Our findings suggest that VCI leads to abnormal diffusion in brain tissue, and that DTI histogram-derived measures might be used to monitor the severity of cognitive impairment in this disease.
Background: This study aims to investigate brain gray matter density (GMD) changes in adolescents... more Background: This study aims to investigate brain gray matter density (GMD) changes in adolescents with Internet addiction (IA) using voxel-based morphometry (VBM) analysis on high-resolution T1-weighted structural magnetic resonance images. Methods: Eighteen IA adolescents and 15 age-and gender-matched healthy controls took part in this study. High-resolution T1-weighted magnetic resonance imaging scans were performed on the two groups. VBM analysis was used to compare the GMD between the two groups. Results: Compared with healthy controls, IA adolescents had lower GMD in the left anterior cingulate cortex, left posterior cingulate cortex, left insula, and left lingual gyrus. Conclusions: Our findings suggested that brain structural changes were present in IA adolescents, and this finding may provide a new insight into the pathogenesis of IA.
In this paper, we presented an indirect approach which automatically separates the splenium of co... more In this paper, we presented an indirect approach which automatically separates the splenium of corpus callosum on mid-sagittal slice of diffusion tensor image (DTI). The callosal fibers were first extracted to decide the corresponding location in the 2D splenium. Using some specific features determined from their geometric properties, the fibers crossing the splenium were clustered into three bundles, which interconnect bilateral temporal, parietal and occipital lobes, respectively. The sub-regions of the splenium were then demarcated by mapping the clusters to the splenium. Similar distribution pattern of these three sub-regions were obtained by applying our method to two real data sets, which indicated the potential applicability of this approach for the further studies of the splenium.
In this article, we present some advances on medical imaging and computing at the National Labora... more In this article, we present some advances on medical imaging and computing at the National Laboratory of Pattern Recognition (NLPR) in the Chinese Academy of Sciences. The first part is computational neuroanatomy. Several novel methods on segmentations of brain tissue and anatomical substructures, brain image registration, and shape analysis are presented. The second part consists of brain connectivity, which includes anatomical connectivity based on diffusion tensor imaging (DTI), functional and effective connectivity with functional magnetic resonance imaging (fMRI). It focuses on abnormal patterns of brain connectivity of patients with various brain disorders compared with matched normal controls. Finally, some prospects and future research directions in this field are also given.
Many studies have reported abnormal changes in relapsing-remitting multiple sclerosis (RRMS) by h... more Many studies have reported abnormal changes in relapsing-remitting multiple sclerosis (RRMS) by histogram and region-of-interest-based methods by using diffusion tenor imaging. However, there are few studies on specific white matter fiber tracts of RRMS. Our study sought to use diffusion tensor tractography-based group mapping to investigate the presence of abnormal diffusion in the normal-appearing pyramidal tract (PYT) of RRMS and its possible mechanism. A PYT probability map was first constructed from data on 20 healthy patients based on the deterministic-based tractography method. The PYT probability map was then applied to 29 RRMS patients to calculate diffusion indices of the PYT. In this study, 4 quantitative indices-fractional anisotropy (FA), directionally averaged diffusion coefficient (D(av)), axial diffusion coefficient (lambda(1)), and radial diffusion coefficient (lambda(23))-were used to characterize the abnormal diffusion. Compared with healthy controls, RRMS patient...
BACKGROUND AND PURPOSE: Normal-appearing brain tissue (NABT) damage was established in multiple s... more BACKGROUND AND PURPOSE: Normal-appearing brain tissue (NABT) damage was established in multiple sclerosis by histology, MR spectroscopy, magnetization transfer imaging and diffusion tensor imaging (DTI). However, whether this phenomenon can be detected in relapsing neuromyelitis optica (RNMO) remains unclear. The aim of this study was to use DTI to investigate the presence of NABT damage in RNMO patients and its
Glaucoma; Lateral geniculate nucleus; Magnetic resonance imaging Summary Purpose: To investigate ... more Glaucoma; Lateral geniculate nucleus; Magnetic resonance imaging Summary Purpose: To investigate the relationship between morphological changes in the lateral geniculate nucleus (LGN), as measured by magnetic resonance imaging (MRI), and damage to the optic disc in primary open-angle glaucoma (POAG) patients. Methods: A total of 23 patients with POAG and 23 age-and gender-matched non-glaucomatous subjects were enrolled. Every patient had structural damage to the optic disc. Cup-to-disc ratio (CDR) and retinal nerve fiber layer thickness (RNFLT) were measured, and 3.0-Tesla MRI examinations performed. Bilateral LGNs were identified and manually extracted, and their maximum heights and volumes compared with the clinical damage to the optic disc. Results: In POAG patients, morphological changes in LGNs and RNFLT were consistently varied (P < 0.05), while a negative correlation between LGN measurements and CDR was observed (P < 0.05).
Background: To investigate nerve fibre damage of the visual pathway in patients with primary open... more Background: To investigate nerve fibre damage of the visual pathway in patients with primary open-angle glaucoma using tract-based spatial statistical analysis of diffusion tensor imaging and correlate these measures with the clinical severity of glaucoma.
Diabetes mellitus affects the brain. Both type 1 and type 2 diabetic patients are associated with... more Diabetes mellitus affects the brain. Both type 1 and type 2 diabetic patients are associated with white matter (WM) damage observable to diffusion tensor imaging (DTI). The underlying histopathological mechanisms, however, are poorly understood. The objectives of this study are 1) to determine whether streptozotocin (STZ)-induced type 1 diabetes is associated with WM damage observable to DTI; and 2) to understand the pathophysiological aspects underlying STZ-induced brain injuries. Male Sprague-Dawley rats received a single intraperitoneal injection of STZ (62 mg/kg). DTI was used to assess brain abnormalities at 4 weeks after induction, combined with histological assessments and ultrastructural analysis. Compared to controls, the STZ-induced rats showed significantly reduced fractional anisotropy (FA) in the motor/somatosensory cortex and striatum. Histologically, the cortex and striatum of the diabetic animals are characterized by demyelination and axonal degradation. In conclusio...
Glaucoma; Lateral geniculate nucleus; Magnetic resonance imaging Summary Purpose: To investigate ... more Glaucoma; Lateral geniculate nucleus; Magnetic resonance imaging Summary Purpose: To investigate the relationship between morphological changes in the lateral geniculate nucleus (LGN), as measured by magnetic resonance imaging (MRI), and damage to the optic disc in primary open-angle glaucoma (POAG) patients. Methods: A total of 23 patients with POAG and 23 age-and gender-matched non-glaucomatous subjects were enrolled. Every patient had structural damage to the optic disc. Cup-to-disc ratio (CDR) and retinal nerve fiber layer thickness (RNFLT) were measured, and 3.0-Tesla MRI examinations performed. Bilateral LGNs were identified and manually extracted, and their maximum heights and volumes compared with the clinical damage to the optic disc. Results: In POAG patients, morphological changes in LGNs and RNFLT were consistently varied (P < 0.05), while a negative correlation between LGN measurements and CDR was observed (P < 0.05).
To prospectively evaluate diffusion indexes of the corticospinal tract (CST), corpus callosum (CC... more To prospectively evaluate diffusion indexes of the corticospinal tract (CST), corpus callosum (CC), optic radiation (OR), and cingulum in patients with neuromyelitis optica (NMO) without visible lesions in the brain.
Previous studies demonstrated that primary open angle glaucoma (POAG) is associated with abnormal... more Previous studies demonstrated that primary open angle glaucoma (POAG) is associated with abnormal brain structure; however, little is known about the changes in the local synchronization of spontaneous activity. The main objective of this study was to investigate spontaneous brain activity in patients with POAG using regional homogeneity (ReHo) analysis based on resting state functional magnetic resonance imaging (rs-fMRI). Thirty-nine POAG patients and forty-one age- and gender- matched healthy controls were finally included in the study. ReHo values were used to evaluate spontaneous brain activity and whole brain voxel-wise analysis of ReHo was carried out to detect differences by region in spontaneous brain activity between groups. Compared to controls, POAG patients showed increased ReHo in the right dorsal anterior cingulated cortex, the bilateral medial frontal gyrus and the right cerebellar anterior lobe, and decreased ReHo in the bilateral calcarine, bilateral precuneus gryus, bilateral pre/postcentral gyrus, left inferior parietal lobule and left cerebellum posterior lobe. A multiple linear regression analysis was performed to explore the relationships between clinical measures and ReHo by region showed significant group differences in the POAG group. Negative correlations were found between age and the ReHo values of the superior frontal gyrus (r = -0.323, p = 0.045), left calcarine (r = -0.357, p = 0.026) and inferior parietal lobule (r = -0.362, p = 0.024). A negative correlation was found between the ReHo values of the left precuneus and the cumulative mean defect (r = -0.400, p = 0.012). POAG was associated with abnormal brain spontaneous activity in some brain regions and such changed regional activity may be associated with clinical parameters. Spontaneous brain activity may play a role in POAG initiation and progression.
Seed-based cross-correlation analysis (sCCA) and independent component analysis have been widely ... more Seed-based cross-correlation analysis (sCCA) and independent component analysis have been widely employed to extract functional networks from the resting state functional magnetic resonance imaging data. However, the results of sCCA, in terms of both connectivity strength and network topology, can be sensitive to seed selection variations. ICA avoids the potential problems due to seed selection, but choosing which component(s) to represent the network of interest could be subjective and problematic. In this study, we proposed a seed-based iterative cross-correlation analysis (siCCA) method for resting state brain network analysis. The method was applied to extract default mode network (DMN) and stable task control network (STCN) in two independent datasets acquired from normal adults. Compared with the networks obtained by traditional sCCA and ICA, the resting state networks produced by siCCA were found to be highly stable and independent on seed selection. siCCA was used to analyze DMN in first-episode major depressive disorder (MDD) patients. It was found that, in the MDD patients, the volume of DMN negatively correlated with the patients&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; social disability screening schedule scores.
Background: Internet addiction disorder (IAD) is currently becoming a serious mental health issue... more Background: Internet addiction disorder (IAD) is currently becoming a serious mental health issue around the globe. Previous studies regarding IAD were mainly focused on associated psychological examinations. However, there are few studies on brain structure and function about IAD. In this study, we used diffusion tensor imaging (DTI) to investigate white matter integrity in adolescents with IAD.
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