【作者】 沈瑾；

【导师】 冯晓源； 李克； 刘含秋；

【作者基本信息】 复旦大学 ， 影像医学与核医学， 2007， 博士

【摘要】 第一部分儿童大脑白质纤维磁共振弥散张量成像技术参数的研究目的：探讨不同的磁共振弥散张量成像扫描参数对儿童大脑白质纤维弥散张量图象的影响，以期获得最佳扫描参数。材料和方法：选取18名健康儿童为研究对象，随机分为3组：弥散敏感梯度方向组、b值组和层厚／层间距组。分别应用不同的扫描参数进行弥散张量磁共振扫描。将所成FA图像和DEC图分为三个不同的等级，进行综合评价。结果：不同的扫描参数所成大脑白质纤维弥散张量图像的质量是不相同的。在b值组，以低b值所成图像较佳，其中以b值=1000s／mm~2为最佳，而高b值所成图像噪声较大。施加的弥散敏感梯度方向数并非越多越好，15个方向与21个方向所成图像没有明显差别，6个方向所成图像质量较差。层厚／层间距对图像的影响最大，层厚越厚，图像的信躁比越大，但是层厚过厚又会影响测量的数值的准确性。结论：在临床工作中，比较实用的大脑白质纤维弥散张量成像扫描参数为：b值=1000s／mm~2，弥散敏感梯度方向数为15，层厚／层间距为5mm／0mm。第二部分正常儿童大脑白质纤维磁共振弥散张量成像研究目的：分析在儿童大脑不同部位白质纤维各向异性所存在的差异及大脑白质纤维随着年龄的增大各向异性变化的规律。材料和方法：测量116名正常儿童(男58例，女58例，年龄6天～18岁)大脑白质不同部位和深部灰质的FA值和ADC值。按照年龄段将其分为8组。小于6个月为第一组(12名，男女各6名)，6个月～小于1岁为第二组(10名，男女各5名)，1岁～小于1.5岁为第三组(10名，男女各5名)，1.5岁～小于2岁为第四组(9名，男4名，女5名)，2～5岁为第五组(15名，男8名，女7名)，6～8岁为第六组(20名，男女各10名)，9～12岁为第七组(20名，男女各10名)，13～18岁为第八组(20名，男女各10名)。测量大脑白质的感兴趣区的FA值和ADC值包括放射冠、上纵束、下纵束、外囊、内囊前肢、内囊后肢、胼胝体膝部、胼胝体压部和皮质脊髓束。同时测量大脑深部灰质包括豆状核、尾状核头部和丘脑的FA值和ADC值。结果：脑内各部位ADC值、FA值在两侧半球间没有统计学差异，在男女之间也没有显著统计学的差异。放射冠、上纵束、胼胝体压部及膝部、内囊前后肢、外囊、下纵束、皮质脊髓束、豆状核、尾状核头部、丘脑不同年龄组间的ADC值和FA值的差异有统计学意义(P＜0.05)。在放射冠、上纵束、胼胝体膝部、内囊前肢、皮质脊髓束在第一组和第二组、第二组和第三组及第三组和第四组间FA值差异有统计学意义(P＜0.05)；内囊后肢、外囊、下纵束、尾状核头部、丘脑在第一组和第二组及第三组和第四组的差异有有统计学意义(P＜0.05)，豆状核各组间FA值差异未见统计学意义(P＞0.05)；放射冠在第六组和第七组间FA值的差异有统计学意义(P＜0.05)；上纵束在第七组和第八组的组间差异有显著统计学意义(P＜0.05)；皮质脊髓束在第五组和第六组、第六组和第七组及第七组和第八组的组间差异有统计学意义(P＜0.05)。放射冠、上纵束、胼胝体膝部及外囊第一组和第二组、第二组和第三组的ADC值的差异有统计学意义(P＜0.05)；胼胝体压部、内囊前后肢、下纵束、皮质脊髓束、尾状核头部、豆状核及丘脑在第一组和第二组的组间差异有统计学意义(P＜0.05)；豆状核在第四组和第五组的组间差异有统计学意义(P＜0.05)；放射冠、内囊前肢和丘脑在第五组和第六组之间的组间差异有统计学意义(P＜0.05)。各感兴趣区的ADC值与年龄呈负相关，放射冠(r=-0.778，P＜0.01)、上纵束(r=-0.775，P＜0.01)、胼胝体压部(r=-0.894，P＜0.01)、胼胝体膝部(r=-0.883，P＜0.01)、内囊前肢(r=-0.794，P＜0.01)、内囊后肢(r=-0.470，P＜0.01)、外囊(r=-0.681，P＜0.01)、下纵束(r=-0.755，P＜0.01)、皮质脊髓束(r=-0.388，P＜0.01)、豆状核(r=-0.527，P＜0.01)、尾状核头部(r=-0.681，P＜0.01)、丘脑(r=-0.639，P＜0.01)。豆状核的FA值与年龄呈负相关(r=-0.424，P＜0.01)，在其他各感兴趣区的FA值与年龄呈正相关，放射冠(r=0.682，P＜0.01)、上纵束(r=0.717，P＜0.01)、胼胝体压部(r=0.710，P＜0.01)、胼胝体膝部(r=0.641，P＜0.01)、内囊前肢(r=0.708，P＜0.01)、内囊后肢(r=0.703，P＜0.01)、外囊(r=0.658，P＜0.01)、下纵束(r=0.713，P＜0.01)、皮质脊髓束(r=0.830，P＜0.01)、尾状核头部(r=0.753，P＜0.01)、丘脑(r=0.749，P＜0.01)。结论：儿童脑组织不同部位的ADC值在两侧半球和性别之间无显著差异；放射冠、上纵束、胼胝体压部及膝部、内囊前后肢、外囊、下纵束、皮质脊髓束、豆状核、尾状核头部、丘脑的ADC值随着年龄的增长而降低，除了豆状核的FA值随着年龄的增长而减低，其余各感兴趣区的FA值均随着年龄的增长而增加。各感兴趣在不同年龄组的FA值和ADC值的差异有统计学意义。本研究所获得的儿童脑组织ADC值、FA值可以作为以后进一步研究的正常参考。第三部分正常儿童大脑白质弥散张量纤维束成像的研究目的：利用磁共振弥散张量纤维束成像技术，研究正常儿童大脑白质纤维束的轨迹、形状、结构、位置、局部解剖和它们之间的相互连接。材料和方法：分别对38名健康儿童分为新生儿组、婴幼儿组、儿童组和青少年组进行弥散张量成像，将所得数据输入个人计算机，应用日本东京大学附属医院放射科影像计算和分析实验室所研制的软件：Volume-onel.72和diffusion TENSOR VisualizerⅡ(dTVⅡ)进行大脑白质纤维束成像。结果：本研究成功地在活体显示不同年龄组大脑主要的白质纤维束，联络纤维主要显示上纵束、下纵束；投射纤维则主要显示皮质脊髓束；联合纤维主要是胼胝体。在新生儿、婴幼儿、学龄期儿童和青少年白质纤维束的密度随着年龄的增加而增加。结论：弥散张量纤维束成像可以显示正常人大脑的主要白质纤维束及其发育过程的变化，为活体白质纤维束的研究开辟了一新的广阔领域。第四部分弥散张量成像在儿童脑部病变的初步研究目的：初步评价磁共振弥散张量成像在儿童临床脑部病变中的大脑白质纤维异常改变中的价值。材料和方法：11例患儿，包括新生儿缺血缺氧性脑病2例(男性，年龄分别为5天，6天)，缺血缺氧后遗改变4例，其中1例为脑室周围白质软化1例(男性，年龄为7月)，脑性瘫痪3例(男性2名，女性1名，年龄12～18岁)，脑皮层发育不良1例(女性，8岁)，急性偏瘫2例(男女各1名，年龄为8岁和13岁)，肾上腺脑白质发育不良2例(男性，年龄分别为11岁和9岁)。所有患儿均行常规MR及DTI检查，并测量ROI的FA值和ADC值。结果：2例新生儿缺血缺氧脑病患儿的放射冠、皮质脊髓束、内囊后肢FA值减低，ADC值在放射冠区轻度增高。1例脑室周围白质软化症的患儿在放射冠、内囊后肢的FA值减低和ADC值升高。3例缺血缺氧性脑病其他后遗改变的患儿放射冠、内囊后肢和皮质脊髓束FA值减低。1例脑皮层发育不良的患儿弥散张量清晰显示了受累及的纤维束。2例急性偏瘫的患儿，可见病变区FA值减低和ADC值的轻度升高。2例肾上腺脑白质营养不良的患儿观察到从病灶中央到病灶周围的FA值的减低和FA值的升高。结论：弥散张量成像可以显示儿童脑部病变导致的大脑白质纤维病理状态下变化的信息，弥散纤维束张量成像能够直观地反映大脑白质纤维束异常变化及其与周围结构的关系。更多还原

【Abstract】 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.更多还原