Study Of Cerebral White Matter Fiber In Children By Using MR Diffusion Tensor Imaging

Study of cerebral white matter fiber by using MR diffusion tensor imagingin childrenPartⅠStudy of the scanning parameter for MR diffusion tensor ofcerebral white matter fiber in childrenPurpose:To search the best scanning parameter for MR diffusion tensor inthe study of the cerebral white matter fiber in children. Materials andMethods:Diffusion tensor imaging of the cerebral white matter fiber wasperformed in 18 healthy children, who were randomly divided into threegroups. Different parameters including b value, the number of thediffusion sensitive gradient direction, and slice thickness were appliedand their impaction on the FA maps and DEC maps were evaluated. Results:Different parameters and different impaction on the quality of the FA andDEC map. The quality of the images was better when b value=1000 s/mm~2 wasused, and noise became greater b balue=3000 s/mm~2. The more the number ofthe direction, the greater the signal noise ration was not. Slice thicknesshad the greatest impaction on the SNR of the images, but too thick sliceinflunced the accuracy of the measurement. Conclusion:Scanning with bvalue=1000 s/mm~2,15 directions and thickness of 5 mm is the practicalprotocol in the study of cerebral white matter fiber in children.PartⅡStudy of anisotropy of cerebral white matter fiber by using MRdiffusion tensor imaging in childrenPurpose:To investigate the difference of the different cerebral whitematter fiber and elucidate changes of the cerebral white matter fiberduring normal aging. Material and Methods: MR diffusion tensor wasperformed in 116 healthy children (58 male and 58 female, age range from6 days to 18 years).Eight age groups were＜6m(6 male and 6 female),6m～＜ly(5 male and 5 female), ly～＜1.5y(5 male and 5 female), 1.5y～＜2y(4male and 5 fenmale), 2y～5y(8 male and 7 female), 6y～8y(10 male and10 female),9y～12y(10 male and 10 female), 13～18y(10 male and 10female).The FA values and ADC values were measured corona radiate,superior longitudinal fasciculus, inferior longitudinal fasciculus, external capsule, anterior limb of the internal capsule, posterior limb ofthe internal capsule, genu of corpus callosum, splenium of corpus callosum,corticospinal tract, lentiform nucleus, head of caudate nucleus andthalamus. Results:There were no significant difference in FA values or ADCvalues between male and female or between the right and left hemisphere.The ADC values and FA values significantly differed in various age groupsin corona radiate, superior longitudinal fasciculus, inferiorlongitudinal fasciculus, external capsule, anterior limb of the internalcapsule, posterior limb of the internal capsule, genu of corpus callosum,splenium of corpus callosum, corticospinal tract, lentiform nucleus, headof caudate nucleus and thalamus in different groups. There weresignificant difference in FA values between group 1 and group 2, group 2and group 3, group3 and group 4 in corona radiate, superior longitudinalfasciculus, anterior limb of the internal capsule, genu of corpus callosum,corticospinal tract. There were significant difference in FA valuesbetween group 1 and group 2, group 3 and group 4 in external capsule,posterior limb of the internal capsule, inferior longitudinal fasciculus,head of caudate nucleus and thalamus. There was no significant differencein FA values in various groups in lentiform nucleus. There weresignificant difference in FA values between group 6 and group 7 in coronaradiate, group 7 and group 8 in superior longitudinal fasciculus. The FAvalues significantly differed between group 5 and group 6, group 6 andgroup 7, group 7 and group 8 in corticospinal tract. There were significantdifference in ADC values between group 1 and group 2, group 2 and group3 in corona radiate, superior longitudinal fasciculus, genu of corpuscallosum, external capsule and corticospinal tract. There were significantdifference in ADC values between group 1 and group 2 in anterior limb ofthe internal capsule, posterior limb of the internal capsule, splenium ofcorpus callosum, inferior longitudinal fasciculus, corticospinal tract,head of caudate nucleus and thalamus. There were significant differencein ADC values between group 4 and group5 in lentiform nucleus and betweengroup 5 and group 6 in corona radiate, anterior limb of the internalcapsule and thalamus. The ADC values significantly decreased withincreasing age in corona radiate(r=-0.778, P＜0.01),superior longitudinal fasciculus(r=-0.775, P＜0.01),splenium of corpus callosum(r=-0.894, P＜0.01),genu of corpus callosum(r=-0.883, P＜0.01),anterior limb of the internal capsule(r=-0.794, P＜0.01),posterior limbof the internal capsul(r=-0.470, P＜0.01),external capsule(r=-0.681,P＜0.01), inferior longitudinal fasciculus (r=-0.755, P＜0.01),corticospinal tract (r=-0.388, P＜0.01), lentiform nucleus(r=-0.527, P＜0.01), head of caudate nucleus (r=-0.681, P＜0.01), thalamus (r=-0.639,P＜0.01).The FA values significantly decreased with increasing age inlentiform nucleus(r=-0.424, P＜0.01).A significant FA increase withadvancing age was observed in corona radiate(r=0.682, P＜0.01),superiorlongitudinal fasciculus(r=0.717, P＜0.01),splenium of corpus callosum(r=0.710, P＜0.01), genu of corpus callosum(r=0.641, P＜0.01), anteriorlimb of the internal capsule(r=0.708, P＜0.01),posterior limb of theinternal capsule (r=0.703, P＜0.01), external capsule (r=0.658, P＜0.01),inferior longitudinal fasciculus(r=0.713, P＜0.01),corticospinaltract(r=0.830, P＜0.01),head of caudate nucleus(r=0.753, P＜0.01),thalamus(r=0.749, P＜0.01).Conclusion:There were no significantdifference in FA values or ADC values between male and female and betweenthe right and left hemisphere. FA value can be used to quantitateanisotropy of the different cerebral white matter fiber. The ADC valuesand FA values significantly differed in various age groups in differentROIs. There were FA values increased and ADC value decreased withincreasing age except the lentiform nucleus in which ADC values and FAvalues were decreased with increasing age.PartⅢStudy of cerebral white matter fiber in normal children by usingdiffusion tensor trackingPurpose:To analyze the trajectory, shape, fiber structure, location,topology and connectivity of normal children cerebral white matter fiberin living human using diffusion tensor tracking. Material and methods: 38healthy children(20 male and 18 female, age range from 6 days to 18 years)divided into group of newborn, group of infant and preschool child, groupof children, and group of adeolescence. All children were examined usingMR diffusion tensor imaging. All data were transferred to a personal computer and were processed with Volume-one1.72 and dTⅦ(TokyoUniversity Japan).Results:The main cerebral white matter fiber pathwayswere observed three dimensionally. Association fibers including superiorlongitudinal fasciculus, inferior longitudinal fasciculus;commissuralfibers including corpus callosumand projection fibers includingcorticospinal tract were revealed. The density of the white matter fibersincreased with increased age. Conclusion:Diffusion tensor tracking isuseful for showing the main cerebral white matter fiber tracts anddeveloping of the white matter fibers. It opens a new field for researchingcerebral white matter fiber in vivo.PartⅣPreliminary clinical study of diffusion tensor imaging inabnormal cerebral white matter fiber in childrenPurpose:To evaluate the usefulness of diffusion tensor imaging inabnormal cerebral white matter in relation to cerebral diseases inchildren. Materials and Methods:we analyzed 11 patients, including 2 casesof hypoxic-ischemic encephalopathy in newborn, 4 cases of post changes ofhypoxic-ischemic encephalopathy including 1 case of periventricularleukomalacia and 3 cases of cerebral palsy, 1 case of cortical dysplasia, 2cases of acute hemiparalysis and 2 cases of X chromosome - linkedadrenoleukodystrophy. All patients were examined by routine MR anddiffusion tensor imaging. Results:Slightly increased of ADC value incorona radiata and decreased of FA value in corona radiate, posterior limbof internal capsule and cortispinal tract were observed in the patientsof hypoxic-ischemic encephalopathy. Increased ADC value and decreased FAvalue of corona radiate and posterior limb of internal capsule were seenin the patient of periventricular leukomalacia. There was a decreased ofcorona radiata, posterior limb of internal capsule and cortispinal tractin patient of post changes of hypoxic-ischemic encephalopathy. We observedthe abnormal cerebral white matter fiber by using diffusion tensor imagingin a patient of cortical dysplasia. FA decreased and ADC slightly increasedin patients of acute hemiparalysis. In patient of X chromosome-linkedadrenoleukodystrophy we found the decreasing ADC value and increasing FA value from the center of the lesion to the edge of thelesion. Conclusion:Diffusion tensor imaging showed the abnormality ofcerebral white matter. Diffusion tensor tracting allowed forvisualization of cerebral white matter three dimensionally.