| Part one:The study of visual pathway of normal adult with DTI and DTTObjective:1,Using 3.0T MRI scanner to study DTI.Describe the FA value and MD value of visual pathway of normal adult., Describe the difference among the different parts of different ages and the relativity between the age and FA value or MD value.2,Do DTT reconstruction in visual pathway of normal adults, to provide reference information to clinc doctors for diagnosising and treatmenting of disease pathwaysMaterials and methods:1,Subject30 normal adult(15man,13 woman, age rang 24-73 years, mean age 48 year)were included in this study. All of the subjects had no diseases affect the nervous system. Subjects were divided into 3 groups according to age:20-39 years old for youth group (10 cases),40-59 years old for middle age group (10 cases),60 years and over for the older group (10 cases)Inclusion criteria:①no nervous system and eye diseases, uncorrected or corrected visual acuity of 1.0 or above;②no previous history of neurological trauma, free of all may potentially affect the central nervous system systemic disease;③no drug, history of alcohol dependence;④normal brain MRI, visual pathway and other brain parenchyma showed no abnormal signal within the lesion.2,Main instruments and equipmentsGE signa Excite3.0T superconducting MRI scanner,8-channel head coil. Inmaging post-processing was done through the Funktool software of GE company's AW 4.3 workstation.3,MR examination methods and parameterAll subjects underwent routine MR and DTI examination. Routine MR examination using DTI use the EPI sequence, applied 25 diffusion gradient directions, b value is 1000s/mm2。Scan range (axial):use the CH-PC plane as the center line, the rang from the top of Lateral cerebral ventricle to the lower edge of thethe occipital lobe. Scan time of 3 minutes 16 seconds asked the volunteers to keep the eye gaze condition and don't move.4,Imaging post-processing and anlysisUsing Functool software to do DTI post-processing. Putting regions of interest (ROI) in optic nerve, optic tract, optic radiation of visual pathway, FA values,MD values were measured. On the basis of FA map and the DEC map, with T1WI, manually select the optic chiasm and lateral geniculate body as the seed points, as the reconstruction situation, in addition with bilateral optic nerve, optic tract as the seed point,to reconstruction the white matter fiber tracts of the three-dimensional reconstruction of DTT of visual pathway.5,Statistical analysisAll statistical processing used the SPSS13.0 statistical analysis software package. Compared the differences of measurements of symmetry anatomical between the left and right hemisphere, compared the differences of measurements of same part between the man and woman, compared the differences of measurements of different parts and different ages, and doing multiple comparisons; Comparison correlation of the measured values in different parts with age. P value is less than 0.05 was considered statistically significant.Result:1,Anisotropy and diffusion characteristics of different parts of the visual pathway in normal(1) Obtain the MRI and DTI map,such as FA map,MD map, DEC map and the T2WI(b=0s/mm2) of different parts and different age groups of visual pathway.(2) The FA, MD values of the visual pathway of the symmetrical part were not significantly different. The FA, MD values of the same part of the visual pathway between different sex were not significantly different.(3) The FA, MD values of the visual pathway of the different part and different age group were significantly different. The cross effect between the age group and part was not significant different.(4) The FA, MD values of the visual pathway of the different age group were significantly different. FA values:youth group> middle age group> old age group; MD values:old age group> middle age group> youth group.(5) The FA, MD values of the visual pathway of the different part were significantly different. Multiple comparisons found:FA values:optic nerve> optic tract> optic radiation; MD values:optic radiation> optic tract> optic nerve(6) Comparisons FA, MD values of the visual pathway in different age group:in the youth group the FA, MD values of the visual pathway of the different part were not significantly different, in the middle and old age group, the FA, MD values of the visual pathway of the different part were significantly different, multiple comparisons found:FA values:optic nerve> optic tract, optic radiation. MD values:optic nerve< optic tract, optic radiation. (7) The FA, MD values of the visual pathway of the different age in the different parts were significantly different. Multiple comparisons found FA values:youth group> old age group; MD values:old age group> youth group.2,The relativity of the FA, MD values and the age factor in the same part of visual pathway was statistically significant.(1) With increasing of age, the FA values of optic nerve, optic tract, optic radiation were negatively correlated with age.(2) With increasing of age, the MD values of optic nerve, optic tract, optic radiation were positive correlated with age.3,Obtain a complete DTT map of white matter fiber tracts of visual pathway in normal adult.Conclusion:1,3.0T MR showed a good anatomy of visual pathway, provided the conditions for precise positioning and quantitative analysis the micro-structural changes of white matter fiber tracts.2,Obtained the normal parameters of FA value and MD value of the viusal pathway of different ages normal adults under the conditions of 3.0T MR examination, provided reference information of the visual pathway related diseases for clinical research. Obtained a normal DTT three-dimensional structure of the visual pathway in vivo, opens up a new areas. for further study the visual pathway diseases.3,.The anisotropic and diffusion characteristics of visual pathway are different in different There are relativity between the anisotropic, diffusion characteristics and age in normal adult, and there are some rules. With age, the FA values of visual pathway in different parts decreased so as the MD values to increased parts..This shows that microstructure of the white matter fiber tracts of the visual pathway of normal adult changes with age, to 60 years old, the white matter fiber of visual pathway in all part occurred significant degeneration, and after the age of 40, and the optic tract, optic radiation changes significantly over the optic nerve. Part two:The study of visual pathway of Glaucoma patients with DTIObjective:Using 3.0T high field MRI scanner to study DTI.Describe the FA and MD of visual pathway of Glaucoma patients, to draw up the reference range of the relevant indicators; and analyzed and compared with the normal control group, in order to find the characteristics of the microstructure of white matter fiber tracts in different parts of of the visual pathway of Primary glaucoma.Materials and methods:Case group:14 glaucoma patients(10man,4 woman, age rang 19-80 years, mean age 49.5 year)were included in this study. Inclusion criteria were bilateral primary glaucoma,there are no other abnormal signal in the conventional T1 FLAIR, T2WI, FLAIR and DWI sequences, there was no previous trauma history of nervous system and other disorders of the nervous system or disease affect the central nervous system.Control group, Scanning methods and parameters, Image post-processing:The same of the first part.All statistical processing used the SPSS 13.0 statistical analysis software package. Compared the differences of age and sex between the control group and case group, Compared the differences of FA value and MD value of same part between the control group and case group. P value is less than 0.05 was considered statistically significant.Result:1,Obtain the FA, MD values of different parts of visual pathway of glaucoma patients.2,The age and sex between the case group and control group were not significantly different.。3,The FA, MD values of all the part of the visual pathway between the case group and control group were significantly different. Performance for the FA value of all parts decreased, MD value increased. Conclusion:1,3.0T MRI can clearly demonstrate the anatomical structure of white matter fiber tracts of viaual pathway of the glaucoma patients,.Obtain the FA, MD values of different parts of visual pathway of the glaucoma patients.Provides the conditions for quantitative analysis and the accurate positioning the micro-institution of white matter fiber bundles;2,The FA values of all part of white matter fiber tracts of the visual pathway of primary glaucoma decreased, MD value increased. It is said that the function of white matter fiber tracts of the visual pathway of primary glaucoma changed significate, It is provide reference information for further study the mechanism of primary glaucoma. |
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