Objective: To explore the magnetic resonance diffusion tensor imaging(MR-DTI) features of in the late stage of Wistar rat C6 brain glioma, and the relationship between fractional anisotropy value and tumor microarchit...Objective: To explore the magnetic resonance diffusion tensor imaging(MR-DTI) features of in the late stage of Wistar rat C6 brain glioma, and the relationship between fractional anisotropy value and tumor microarchitecture. Methods: The concentration of more than 1.0×伊 106/10 μL glioma cells and complete medium were injected stereotactically into the right caudate nucleus of the experimental group(n=35) and control group(n=10), respectively. Conventional MRI, DTI, and enhanced T1 WI scans were Performed using the GE Signa HD× 3.0T MRI scanner about 3-4 weeks after implantation for the rats. Postproeessing was done using the DTI specific software Function Tool to gain FA image. Many ROIs were drawn avoiding hemorrhage, necrosis areas in tumor parenchyma, the value of FA was recorded. Each surviving rat brain was examined histologically using HE and immunohistochemical staining for VEGF and CD34. Pearson correlation analysis was used to determine the relationships between FA values and VEGF, MVD, cell density, respectively. Results: A total of 35 tumor-bearing rats were confirmed the tumor formation by the subsequent MRI and pathological examination. The mean FA values of the tumor and the contralateral brain tissue were 0.17 ± 0.03 and 0.31 ± 0.05 respectively, and the difference was statistically significant(t = 12.80, P <0.05). The mean FA value of grade III glioma(n=12) was 0.16 ± 0.03, and the average FA value of grade IV glioma(n=23) was about 0.18 ± 0.04. There was no significant difference between the two groups(t= 1.92, P> 0.05). FA value in the late stage of Wistar rat C6 brain glioma has significant positive correlation to VEGF, MVD, cell density. The correlation coefficients between FA and VEGF, MVD, and cell density were 0.67, 0.65 and 0.71(P<0.05), respectively. Conclusions: The FA value of rat glioma tumor in the late stage can preoperatively provide an accurate, reliable and noninvasive imaging monitoring method to evaluate the microstructure of glioma( cell density, the extent of angiogenesis, fiber bundle integrity and tumor cell infiltration and so on), predict the biological behavior of the tumor and make out surgical plan.展开更多
Diffusion tensor imaging was performed in 105 volunteers free of central nervous system lesions.No differences were found in fractional anisotropy between the left and right cerebral peduncles among subjects（P 0.05）...Diffusion tensor imaging was performed in 105 volunteers free of central nervous system lesions.No differences were found in fractional anisotropy between the left and right cerebral peduncles among subjects（P 0.05）.The lower limit value of fractional anisotropy was 0.36,and the asymmetry ratio was 0.77.The area and lower limit value of the cerebral peduncles were 0.90 cm2 and 0.83,respectively.These results will be useful in evaluating the diagnosis of Wallerian degeneration following cerebral infarction.展开更多
Dopamine content in the basal ganglia is strongly associated with the degree of dopaminergic neuron loss in the substantia nigra pars com- pacta. Symptoms of Parkinson＇s disease might not arise until more than 50% of...Dopamine content in the basal ganglia is strongly associated with the degree of dopaminergic neuron loss in the substantia nigra pars com- pacta. Symptoms of Parkinson＇s disease might not arise until more than 50% of the substantia nigra pars compacta is lost and the dopamine content in the basal ganglia is reduced by more than 80%. Greater diagnostic sensitivity and specificity would allow earlier detection of Parkinson＇s disease. Diffusion tensor imaging is a recently developed magnetic resonance imaging technique that measures mean diffusiv- ity and fractional anisotropy, and responds to changes in brain microstructure. When the microscopic barrier （including cell membranes, microtubules and other structures that interfere with the free diffusion of water） is destroyed and extracellular fluid volume accumulates, the mean diffusivity value increases; when the integrity of the microstructure （such as myelin） is destroyed, fractional anisotropy value decreases. However, there is no consensus as to whether these changes can reflect the early pathological alterations in Parkinson＇s disease. Here, we established a rat model of Parkinson＇s disease by injecting rotenone （or sunflower oil in controls） into the right suhstantia nigra. Diffusion tensor imaging results revealed that in the stages of disease, at 1, 2, 4, and 6 weeks after rotenone injection, fiactional anisotropy value decreased, but mean diffusivity values increased in the right substantia nigra in the experimental group. Fractional anisotropy values were lower at 4 weeks than at 6 weeks in the right substantia nigra of rats from the experimental group. Mean diffusivity values were mark- edly greater at 1 week than at 6 weeks in the right corpus striatum of rats from the experimental group. These findings suggest that mean diffusivity and fractional anisotropy values in the brain of rat models of Parkinson＇s disease 4 weeks after model establishment can reflect early degeneration of dopaminergic neurons. ＇The change in fractional anisotropy values after destruction of myelin integrity is likely to be of greater early diagnostic significance than the change in mean diffusivity values.展开更多
BACKGROUND： The corticospinal tract is an important tract for conducting motor function. The majority of studies focus on lesions of the corticospinal tract on appearance and function, whereas observation of normal c...BACKGROUND： The corticospinal tract is an important tract for conducting motor function. The majority of studies focus on lesions of the corticospinal tract on appearance and function, whereas observation of normal corticospinal pathways can also improve understanding of lesion outcomes. OBJECTIVE： To observe the normal adult corticospinal tract using a diffusion tensor imaging technique to analyze fractional anisotropy （FA） in different levels of the brain. DESIGN, TIME AND SETTING： Neuroimaging observation was performed in the MRI Department, First Affiliated Hospital of Kunming Medical College in China, from October 2005 to October 2008. PARTICIPANTS： A total of 30 healthy adults were selected from the Department of MRI, First Affiliated Hospital of Kunming Medical College in China, from October 2005 to October 2008, and people with nervous system symptoms and signs were excluded. METHODS： Participants with normal conventional MRI results underwent diffusion tensor imaging examination in a 1.5 T GE MRI （slice thickness 4-5 mm, slice gap 0） for gradient data acquisition from 15 directions. The scanning involved the entire brain from the inferior medulla oblongata to the inferior cranial plate. Imaging post-processing was performed to obtain FA values; a paired t-test was applied for statistical analysis. MAIN OUTCOME MEASURES： FA values of the bilateral corticospinal tract in the medulla oblongata, pons, cerebral peduncle, basal ganglia, corona radiata, and centrum semiovale. RESULTS： FA values in the medulla oblongata and centrum semiovale were similar （P 〉 0.01）. FA values of left corticospinal tract were significantly greater than the right side in the pons, cerebral peduncle, basal ganglia and corona radiata （P 〈 0.01）. CONCLUSION： FA values vary by brain levels, including pons, cerebral peduncle, basal ganglia, and corona radiata. Moreover, FA values of the left corticospinal tract pathway were greater than the right side, which may relate to right handedness.展开更多
目的应用磁共振弥散峰度成像(diffusional kurtosis imaging,DKI)研究阻塞性睡眠呼吸暂停低通气综合征(OSAHS)患者的脑白质变化情况。方法选取2017年11月~2021年6月行多导睡眠监测(PSG)确诊为OSAHS的患者38例(OSAHS组),另选取性别、年...目的应用磁共振弥散峰度成像(diffusional kurtosis imaging,DKI)研究阻塞性睡眠呼吸暂停低通气综合征(OSAHS)患者的脑白质变化情况。方法选取2017年11月~2021年6月行多导睡眠监测(PSG)确诊为OSAHS的患者38例(OSAHS组),另选取性别、年龄相匹配的非OSAHS者32例(对照组);所有受试者均行DKI扫描,通过比较两组各脑区的峰度各向异性分数(kurtosis fractional anisotropy,KFA)找出差异性脑区并分析OSAHS组患者差异性脑区的KFA值与PSG结果中呼吸暂停低通气指数(AHI)、最低血氧饱和度(lowest saturation oxygen,LSaO_(2))、血氧饱和度小于90%时间占监测总时间的百分比(the percent of the total record time spent below 90%oxygen saturation,TS90%)的相关性。结果OSAHS组在胼胝体、双侧放射冠、扣带回以及右侧小脑上脚、下脚区域白质纤维束的KFA值均低于对照组(P<0.05)。在控制年龄和体重指数(BMI)两个指标的前提下行偏相关分析得出:OSAHS组患者的AHI与胼胝体、左侧后放射冠、右侧前放射冠、扣带回的KFA值呈负相关(r=-0.344、-0.380、-0.406、-0.537,P<0.05);LSaO_(2)与胼胝体、左侧后放射冠、右侧前放射冠、扣带回、右侧小脑上脚的KFA值呈正相关(r=0.366、0.406、0.446、0.404、0.342,P<0.05);TS90%与胼胝体、左侧后放射冠、右侧前放射冠、扣带回、右侧小脑上脚、右侧小脑下脚的KFA值呈负相关(r=-0.414、-0.352、-0.355、-0.336、-0.456、-0.360,P<0.05)。结论OSAHS患者夜间的反复呼吸暂停和低氧血症会导致部分脑区白质纤维受损,从而引发对应的脑功能障碍。展开更多
基金supported by the National Natural Science Foundation of China,No.81360228the Natural Science Foundation of Hainan Province,No.813259the Scientific Research Foundation of Haikou Municipal Science and Technology Information Industry Bureau,No.2013-72
文摘Objective: To explore the magnetic resonance diffusion tensor imaging(MR-DTI) features of in the late stage of Wistar rat C6 brain glioma, and the relationship between fractional anisotropy value and tumor microarchitecture. Methods: The concentration of more than 1.0×伊 106/10 μL glioma cells and complete medium were injected stereotactically into the right caudate nucleus of the experimental group(n=35) and control group(n=10), respectively. Conventional MRI, DTI, and enhanced T1 WI scans were Performed using the GE Signa HD× 3.0T MRI scanner about 3-4 weeks after implantation for the rats. Postproeessing was done using the DTI specific software Function Tool to gain FA image. Many ROIs were drawn avoiding hemorrhage, necrosis areas in tumor parenchyma, the value of FA was recorded. Each surviving rat brain was examined histologically using HE and immunohistochemical staining for VEGF and CD34. Pearson correlation analysis was used to determine the relationships between FA values and VEGF, MVD, cell density, respectively. Results: A total of 35 tumor-bearing rats were confirmed the tumor formation by the subsequent MRI and pathological examination. The mean FA values of the tumor and the contralateral brain tissue were 0.17 ± 0.03 and 0.31 ± 0.05 respectively, and the difference was statistically significant(t = 12.80, P <0.05). The mean FA value of grade III glioma(n=12) was 0.16 ± 0.03, and the average FA value of grade IV glioma(n=23) was about 0.18 ± 0.04. There was no significant difference between the two groups(t= 1.92, P> 0.05). FA value in the late stage of Wistar rat C6 brain glioma has significant positive correlation to VEGF, MVD, cell density. The correlation coefficients between FA and VEGF, MVD, and cell density were 0.67, 0.65 and 0.71(P<0.05), respectively. Conclusions: The FA value of rat glioma tumor in the late stage can preoperatively provide an accurate, reliable and noninvasive imaging monitoring method to evaluate the microstructure of glioma( cell density, the extent of angiogenesis, fiber bundle integrity and tumor cell infiltration and so on), predict the biological behavior of the tumor and make out surgical plan.
基金the grant of Science and Technology Bureau of Zhongshan, No. 20102C146
文摘Diffusion tensor imaging was performed in 105 volunteers free of central nervous system lesions.No differences were found in fractional anisotropy between the left and right cerebral peduncles among subjects（P 0.05）.The lower limit value of fractional anisotropy was 0.36,and the asymmetry ratio was 0.77.The area and lower limit value of the cerebral peduncles were 0.90 cm2 and 0.83,respectively.These results will be useful in evaluating the diagnosis of Wallerian degeneration following cerebral infarction.
基金supported by the Research Grant of Hebei Province Science and Technology Project of China,No.1427777118D
文摘Dopamine content in the basal ganglia is strongly associated with the degree of dopaminergic neuron loss in the substantia nigra pars com- pacta. Symptoms of Parkinson＇s disease might not arise until more than 50% of the substantia nigra pars compacta is lost and the dopamine content in the basal ganglia is reduced by more than 80%. Greater diagnostic sensitivity and specificity would allow earlier detection of Parkinson＇s disease. Diffusion tensor imaging is a recently developed magnetic resonance imaging technique that measures mean diffusiv- ity and fractional anisotropy, and responds to changes in brain microstructure. When the microscopic barrier （including cell membranes, microtubules and other structures that interfere with the free diffusion of water） is destroyed and extracellular fluid volume accumulates, the mean diffusivity value increases; when the integrity of the microstructure （such as myelin） is destroyed, fractional anisotropy value decreases. However, there is no consensus as to whether these changes can reflect the early pathological alterations in Parkinson＇s disease. Here, we established a rat model of Parkinson＇s disease by injecting rotenone （or sunflower oil in controls） into the right suhstantia nigra. Diffusion tensor imaging results revealed that in the stages of disease, at 1, 2, 4, and 6 weeks after rotenone injection, fiactional anisotropy value decreased, but mean diffusivity values increased in the right substantia nigra in the experimental group. Fractional anisotropy values were lower at 4 weeks than at 6 weeks in the right substantia nigra of rats from the experimental group. Mean diffusivity values were mark- edly greater at 1 week than at 6 weeks in the right corpus striatum of rats from the experimental group. These findings suggest that mean diffusivity and fractional anisotropy values in the brain of rat models of Parkinson＇s disease 4 weeks after model establishment can reflect early degeneration of dopaminergic neurons. ＇The change in fractional anisotropy values after destruction of myelin integrity is likely to be of greater early diagnostic significance than the change in mean diffusivity values.
文摘BACKGROUND： The corticospinal tract is an important tract for conducting motor function. The majority of studies focus on lesions of the corticospinal tract on appearance and function, whereas observation of normal corticospinal pathways can also improve understanding of lesion outcomes. OBJECTIVE： To observe the normal adult corticospinal tract using a diffusion tensor imaging technique to analyze fractional anisotropy （FA） in different levels of the brain. DESIGN, TIME AND SETTING： Neuroimaging observation was performed in the MRI Department, First Affiliated Hospital of Kunming Medical College in China, from October 2005 to October 2008. PARTICIPANTS： A total of 30 healthy adults were selected from the Department of MRI, First Affiliated Hospital of Kunming Medical College in China, from October 2005 to October 2008, and people with nervous system symptoms and signs were excluded. METHODS： Participants with normal conventional MRI results underwent diffusion tensor imaging examination in a 1.5 T GE MRI （slice thickness 4-5 mm, slice gap 0） for gradient data acquisition from 15 directions. The scanning involved the entire brain from the inferior medulla oblongata to the inferior cranial plate. Imaging post-processing was performed to obtain FA values; a paired t-test was applied for statistical analysis. MAIN OUTCOME MEASURES： FA values of the bilateral corticospinal tract in the medulla oblongata, pons, cerebral peduncle, basal ganglia, corona radiata, and centrum semiovale. RESULTS： FA values in the medulla oblongata and centrum semiovale were similar （P 〉 0.01）. FA values of left corticospinal tract were significantly greater than the right side in the pons, cerebral peduncle, basal ganglia and corona radiata （P 〈 0.01）. CONCLUSION： FA values vary by brain levels, including pons, cerebral peduncle, basal ganglia, and corona radiata. Moreover, FA values of the left corticospinal tract pathway were greater than the right side, which may relate to right handedness.
文摘目的应用磁共振弥散峰度成像(diffusional kurtosis imaging,DKI)研究阻塞性睡眠呼吸暂停低通气综合征(OSAHS)患者的脑白质变化情况。方法选取2017年11月~2021年6月行多导睡眠监测(PSG)确诊为OSAHS的患者38例(OSAHS组),另选取性别、年龄相匹配的非OSAHS者32例(对照组);所有受试者均行DKI扫描,通过比较两组各脑区的峰度各向异性分数(kurtosis fractional anisotropy,KFA)找出差异性脑区并分析OSAHS组患者差异性脑区的KFA值与PSG结果中呼吸暂停低通气指数(AHI)、最低血氧饱和度(lowest saturation oxygen,LSaO_(2))、血氧饱和度小于90%时间占监测总时间的百分比(the percent of the total record time spent below 90%oxygen saturation,TS90%)的相关性。结果OSAHS组在胼胝体、双侧放射冠、扣带回以及右侧小脑上脚、下脚区域白质纤维束的KFA值均低于对照组(P<0.05)。在控制年龄和体重指数(BMI)两个指标的前提下行偏相关分析得出:OSAHS组患者的AHI与胼胝体、左侧后放射冠、右侧前放射冠、扣带回的KFA值呈负相关(r=-0.344、-0.380、-0.406、-0.537,P<0.05);LSaO_(2)与胼胝体、左侧后放射冠、右侧前放射冠、扣带回、右侧小脑上脚的KFA值呈正相关(r=0.366、0.406、0.446、0.404、0.342,P<0.05);TS90%与胼胝体、左侧后放射冠、右侧前放射冠、扣带回、右侧小脑上脚、右侧小脑下脚的KFA值呈负相关(r=-0.414、-0.352、-0.355、-0.336、-0.456、-0.360,P<0.05)。结论OSAHS患者夜间的反复呼吸暂停和低氧血症会导致部分脑区白质纤维受损,从而引发对应的脑功能障碍。
