Diffusion tensor magnetic resonance imaging in brain white matter diseases

Objective To evaluate the usefulness of diffusion tensor MR imaging in brain white matter diseases. Methods A combined conventional and diffusion tensor MRI were obtained from 10 multiple sclerosis ,10 multiple lacunar infarction,3 cysticercosis,1 angiitis ,1 morphinist and 10 healthy control volunteers. After obtaining mean diffusivity (D) and fractional anisotropy images and image coregistration, the correlations of the lesions and the white matter pathways were investigated. D and AI values were measured form four big lesions which can be seen in T2WI and compared to contralateral white matter. Also D and AI value of four different anatomic locations of normal appearing white matter regions were measured in all patients and controls. Results Whereas the lesions of infarction, cysticercosis and angiitis were in and outside the white matter pathways, all plaques of multiple sclerosis were inside the whit matter pathways. The brain white matter lesions by 1 morphinist were beside the lateral ventricle with big patchy appearance, which was partly inside white matter. For MS, D value was higher in lesions than control white matter. But for other diseases, D value could be seen higher or lower compared to healthy side. AI values were lower in all lesions. D value was higher and AI was lower in normal appearing brain white matter when comparing MS to other cases or healthy control volunteers. Conclusion Diffusion tensor MR images can determine the correlations of the lesions and brain white matter pathways. The changes of D and AI values can improve specificity in differential diagnoses though quantitatively analyzing the tissue damage in lesions and normal appearing brain white matter.

Low-frequency blood oxygen level-dependent fluctuations in the brain white matter： more than just noise

The spontaneous activity of the blood oxygen level-dependent(BOLD)signal has been demonstrated as a promising way for understanding how the brain intrinsically organized.However,most of these studies focused solely on the spontaneous activity in gray matter(GM)and not on white matter(WM).This is

Maternal stress exposure during pregnancy impairs ultrastructural changes in the white matter and reduces cognitive function in offspring mice

Objective:To explore whether maternal stress exposure during pregnancy impairs cognitive function and white matter ultrastructure in offspring mice.Methods:The parent rats were divided into two groups:pressure exposure group(group PE)and control group(group C),and the positive date of vaginal smear of female SD rats was day 0 of gestation.Female mice in group PE were exposed to binding pressure(3 times/day)on day 14-20 of gestation for 45 min-1 h/time.Behavioral tests(Morris water maze and Y maze)were performed on 1-month-old offspring mice followed by cardiac perfusion of fixed brain specimens and placement in mixed fixative solution.The total volume of white matter,total length and volume of myelinated nerve fibers and total length and volume of myelin sheath were calculated using modern stereoscopic methods,and the inner and outer diameter and inner and outer circumference of the myelin sheath were analyzed.Results:1)Behavioral tests:compared with the group C,the average latency of the 3th and 4th day in the group PE were significantly prolonged,the percentage of the resting time in the quadrant of the platform and the frequency of acrossing the effective area of platform in the fifth day of space exploration experiment were significantly reduced of Morris water maze test,and visiting distance,duration and numbers in novel arm significantly increased of Y-maze test(P<0.05).2)Compared with group C,the total volume of white matter,total length of myelinated nerve fibers,total volume of myelinated nerve fibers and myelin sheath in the group PE were significantly reduced(P<0.05),the inner diameter and outer diameter of myelin sheath decreased significantly(P<0.05),and the inner perimeter,outer perimeter and inner and outer perimeter differences increased significantly(P<0.05).3)There was a correlation between behavioral test results and white matter ultrastructure measurement results.Conclusions:Maternal stress exposure during pregnancy could impair the cognitive function and white matter and its ultrastructure in the offspring,and there was a correlation between decreased cognitive function and white matter damages.

Age-related changes of lateral ventricular width and periventricular white matter in the human brain: a diffusion tensor imaging study

Introduction Aging is the accumulation of multidimensional deterioration of process- ing of biological, psychological, and social changes with expansion over time （Bowen and Atwood, 2004; Grady, 2012）. Aging-related changes are typically accompanied by decline in cognitive function, urinary control, sensory-motor function, and gait ability （Bradley et al., 1991; Bowen and Atwood, 2004; Hedden and Gabrieli, 2004; Grady, 2012; Moran et al., 2012）. In addition, a number of studies have suggested changes in brain structure with normal aging, such as decrease in cortical thickness or increase in ventricular width （Blatter et al., 1995; Tang et al., 1997; Uylings and de Brabander, 2002; Preul et al., 2006; Apostolova et al., 2012）. In particular, ventricular enlargement has been suggested as a structural biomarker for normal aging and progression of some illnesses, such as Alzheimer＇s disease （Blatter et al., 1995; Tang et al.,

Bone morphogenetic protein signaling：a promising target for white matter protection in perinatal brain injury

Prematurely born newborns,as well as those born at term,may suffer from several types of brain injury including hypoxic-ischemic injury,intracranial hemorrhage,both intraventricular and parenchymal,and injury that is the consequence of intrauterine growth restriction（IUGR）.Injury of all types can impact the motor and cognitive abilities of survivors.The mechanisms leading to disability are not completely understood.

Diffusion tensor imaging assesses white matter injury in neonates with hypoxic-ischemic encephalopathy

With improvements in care of at-risk neonates, more and more children survive. This makes it increasingly important to assess, soon after birth, the prognosis of children with hypoxic-ischemic encephalopathy. Computed tomography, ultrasound, and conventional magnetic resonance imaging are helpful to diagnose brain injury, but cannot quantify white matter damage. In this study, ten full-term infants without brain injury and twenty-two full-term neonates with hypoxic-ischemic encephalopathy （14 moderate cases and 8 severe cases） underwent diffusion tensor imaging to assess its feasibility in evaluating white matter damage in this condition. Results demonstrated that fractional anisotropy, voxel volume, and number of fiber bundles were different in some brain areas between infants with brain injury and those without brain injury. The correlation between fractional anisotropy values and neonatal behavioral neurological assessment scores was closest in the posterior limbs of the internal capsule. We conclude that diffusion tensor imaging can quantify white matter injury in neonates with hypoxic-ischemic encephalopathy.

Correlation between white matter damage and gray matter lesions in multiple sclerosis patients

We observed the characteristics of white matter fibers and gray matter in multiple sclerosis patients, to identify changes in diffusion tensor imaging fractional anisotropy values following white matter fiber injury. We analyzed the correlation between fractional anisotropy values and changes in whole-brain gray matter volume. The participants included 20 patients with relapsing-remitting multiple sclerosis and 20 healthy volunteers as controls. All subjects underwent head magnetic resonance imaging and diffusion tensor imaging. Our results revealed that fractional anisotropy values decreased and gray matter volumes were reduced in the genu and splenium of corpus callosum, left anterior thalamic radiation, hippocampus, uncinate fasciculus, right corticospinal tract, bilateral cingulate gyri, and inferior longitudinal fasciculus in multiple sclerosis patients. Gray matter volumes were significantly different between the two groups in the right frontal lobe（superior frontal, middle frontal, precentral, and orbital gyri）, right parietal lobe（postcentral and inferior parietal gyri）, right temporal lobe（caudate nucleus）, right occipital lobe（middle occipital gyrus）, right insula, right parahippocampal gyrus, and left cingulate gyrus. The voxel sizes of atrophic gray matter positively correlated with fractional anisotropy values in white matter association fibers in the patient group. These findings suggest that white matter fiber bundles are extensively injured in multiple sclerosis patients. The main areas of gray matter atrophy in multiple sclerosis are the frontal lobe, parietal lobe, caudate nucleus, parahippocampal gyrus, and cingulate gyrus. Gray matter atrophy is strongly associated with white matter injury in multiple sclerosis patients, particularly with injury to association fibers.

Therapeutic Effects of Myriocin in Experimental Alcohol-Related Neurobehavioral Dysfunction and Frontal Lobe White Matter Biochemical Pathology

Background & Objective: Chronic excessive alcohol consumption causes white matter degeneration with myelin loss and impaired neuronal conductivity. Subsequent rarefaction of myelin accounts for the sustained deficits in cognition, learning, and memory. Correspondingly, chronic heavy or repeated binge alcohol exposures in humans and experimental models alter myelin lipid composition leading to build-up of ceramides which can be neurotoxic and broadly inhibitory to brain functions. Methods: This study examined the effects of chronic + binge alcohol exposures (8 weeks) and intervention with myriocin, a ceramide inhibitor, on neurobehavioral functions (Open Field, Novel Object Recognition, and Morris Water Maze tests) and frontal lobe white matter myelin lipid biochemical pathology in an adult Long-Evans rat model. Results: The ethanol-exposed group had significant deficits in executive functions with increased indices of anxiety and impairments in spatial learning acquisition. Myriocin partially remediated these effects of ethanol while not impacting behavior in the control group. Ethanol-fed rats had significantly smaller brains with broadly reduced expression of sulfatides and reduced expression of two of the three sphingomyelins detected in frontal white matter. Myriocin partially resolved these effects corresponding with improvements in neurobehavioral function. Conclusion: Therapeutic strategies that support cerebral white matter myelin expression of sulfatide and sphingomyelin may help remediate cognitive-behavioral dysfunction following chronic heavy alcohol consumption in humans.

Adaptation to Fluctuating Neuronal Signal Traffic for Brain Connectivity

Brain connectivity is commonly studied in terms of causal interaction or statistical dependency between brain regions. In this analysis paper, we draw attention to the constraining effect the dynamics of fiber tract connections may impose on neuronal signal traffic. We propose a model developed by Copelli and Kinouchi (l.c.) for a different purpose to safeguard signal transmission for brain connectivity by ensuring dynamic adaptation of signal reception to a wide frequency range of traffic flow over connecting fiber tracts. Gap junction connectivity would confer to neuronal groups the capacity of acting as collectives for dynamical adaptability to impinging neural traffic thereby forestalling traffic congestion and overload. It is suggested that applying this model to signal reception in brain connectivity would deliver the required functionality as a collective achievement of the interrelations between neurons and gap junctions, the latter regulated by glia.

Cornel iridoid glycoside protects against white matter lesions induced by cerebral ischemia via activation of neuregulin-1 pathway in rats

Ischemic stroke often elicits profound white matter lesions, which results in poor neurological outcomes and impairing the recovery in post-stroke. However, few studies have focused on white matter lesions caused by cerebral ischemia. The present study was aimed to investigate the effects of cornel iridoid glycoside(CIG), a main active component extracted from Cornus officinalis, on the white matter injury induced by ischemic stroke. CIG(60 and 120 mg·kg-1) were administered intragastrically 6 h after middle cerebral artery occlusion reperfusion(MCAO) surgery once a day for 7 d. A series of behavioral tests were carried out to evaluate the neurological function of MCAO rats. White matter structure was detected by luxol fast blue staining and transmission electron microscopy. Immunohistochemical staining was used to assess myelin loss, oligodendrocytes maturation and glial activation. Results showed that CIG remarkably decreased neurological deficit score, accelerated the recovery of somatosensory and motor functions, and ameliorated the memory deficit in MCAO rats. CIG alleviated white matter lesions and demyelination, increased myelin basic protein expression and the number of mature oligodendrocytes in the corpus callosum of MCAO rats. Besides, CIG inhibited the activation of microglia and astrocytes. Further data obtained by western blot analysis indicated that CIG increased the expression of brain-derived neurotrophic factor(BDNF)/p-Trk B, neuregulin-1/Erb B, and PI3 K p110α/p-Akt/p-m TOR in the corpus callosum of MCAO rats. Our findings demonstrated that CIG protected against white matter lesions induced by cerebral ischemia and the mechanisms were partially contributed to increasing BDNF and activating neuregulin-1/Erb B signaling and its downstream PI3 K/Akt/m TOR pathway in white matter.

磁共振波谱成像联合弥散加权成像在早产儿脑白质损伤诊断及预后评估中的应用

目的探讨磁共振波谱成像(MRS)联合弥散加权成像(DWI)在早产儿脑白质损伤早期诊断以及其预后评估中的应用价值。方法选取2021年1月-2023年1月102例脑白质损伤早产儿作为病例组,同期选取98例非脑白质损伤早产儿作为对照组,记录两组早产儿相关临床指标,并在出生后7d实施MRS、DWI检查,比较两组MRS代谢指标、DWI参数差异,使用点二列相关性检验MRS代谢指标、DWI参数与早产儿脑白质损伤的关系,并绘制受试者工作曲线(ROC)分析MRS联合DWI对早产儿脑白质损伤的早期诊断价值。予以病例组患儿长期随访,在矫正年龄6个月时使用Gesell发育诊断量表将患儿分为预后不良组与预后良好组,比较并分析2组患儿MRS代谢指标、DWI参数对早产儿脑白质损伤预后的评估价值。结果病例组N-乙酰天冬氨酸(NAA)、NAA/Cr、rADC明显低于对照组,肌酸(Cr)明显高于对照组,差异有统计学意义(P<0.05)。经点二列相关性检验显示NAA、NAA/Cr、rADC与早产儿脑白质损伤存在负相关关系(r<0,P<0.05);Cr与早产儿脑白质损伤存在正相关关系(r>0,P<0.05)。绘制ROC显示NAA、Cr、NAA/Cr以及rADC对早产儿脑白质损伤诊断具有较低的诊断价值,AUC分别为0.629、0.630、0.605、0.603;MRS联合DWI具有良好的诊断价值,AUC为0.713。随访结果显示102例患儿中21例为边缘状态,53例为发育异常,共74例为预后不良组,另28例发育良好为预后良好组。预后不良组患儿NAA、NAA/Cr、rADC明显低于预后良好组,Cr明显高于预后良好组,差异有统计学意义(P<0.05)。经点二列相关性检验显示NAA、NAA/Cr、rADC与脑白质损伤患儿预后不良存在负相关关系(r<0,P<0.05);Cr与预后不良存在正相关关系(r>0,P<0.05)。绘制ROC曲线显示NAA、NAA/Cr以及rADC对脑白质损伤患儿预后具有较低的评估价值,AUC分别为0.641、0.639、0.688;Cr、MRS联合DWI对脑白质损伤患儿预后具有良好的评估价值,AUC分别为0.755、0.833,以联合评估价值最高。结论MRS联合DWI对早产儿脑白质损伤以及其预后均有良好的评估价值。

脑白质病变及大脑皮层厚度与老年轻型卒中后认知功能障碍的相关性研究

目的探讨老年轻型卒中后认知功能障碍(PSCI)与脑白质病变、大脑皮层厚度的关系。方法回顾性分析158例老年轻型卒中病人的临床资料,根据MoCA评估结果分为非PSCI组和PSCI组(MoCA<26分),比较2组的基线资料、MRI影像改变、大脑皮层厚度,并采用多因素Logistic回归分析老年轻型卒中病人发生PSCI的影响因素。结果PSCI组与非PSCI组的腔隙性缺血灶、脑微出血、DWI阳性病变及血管间隙扩大检出率差异无统计学意义(P>0.05)。PSCI组年龄大于非PSCI组,脑白质病变较非PSCI组严重(P<0.05)。2组的左额下回三角部及右额下回三角部皮质厚度差异无统计学意义(P>0.05),但PSCI组左眶额部、右眶额部、左额中回及右额中回的皮质厚度均明显低于非PSCI组(P<0.05)。多因素分析显示,年龄、中重度脑白质病变均为老年轻型卒中病人发生PSCI的危险因素(OR=1.704、1.826,均P<0.05),前额叶脑皮质厚度(左眶额部、右眶额部、左额中回、右额中回)为老年轻型卒中病人发生PSCI的保护因素(OR=0.820、0.838、0.834、0.827,均P<0.05)。结论年龄、脑白质中重度病变及前额叶脑皮质厚度变薄均与PSCI密切相关,通过头颅MRI检查脑白质及大脑皮质厚度变化,可为临床预测PSCI的发生提供参考依据。

缓解期双相情感障碍Ⅰ型患者白质纤维结构异常的扩散张量成像研究

目的:探讨缓解期双相情感障碍(BD)Ⅰ型患者脑白质神经纤维束的改变,及患者认知功能与脑白质病变的关系。方法:采用汉密尔顿抑郁量表(HAMD),杨氏躁狂量表(YMRS)和重复性成套神经心理状态量表(RBANS)对患者进行入组的筛查与认知评估。应用3.0T磁共振仪对76例缓解期BD-Ⅰ型患者以及66例年龄、性别相匹配的健康志愿者(对照组)行DTI扫描,使用PANDA软件包提取全脑白质纤维束的各向异性分数(FA)和平均扩散率(MD),采用独立样本t检验进行组间差异比较,及Pearson相关分析探讨BD组中各纤维束的FA与临床可重复神经心理状态测验(RBANS)评分间的相关性。结果:相较于对照组,BD-Ⅰ型组的左、右侧钩束、右侧上纵束、右侧下额枕束及左侧毯束的FA值降低,MD值升高,差异均具有统计学意义(P<0.01)。BD-Ⅰ型组的左、右侧钩束、右侧上纵束和右侧下额枕束的FA值与RBANS量表评估的总分及即刻记忆、延迟记忆、视觉广度和注意力四项因子的评分均具有正相关关系(r=0.32~0.44,P均<0.05)。结论:缓解期双相障碍BD I型患者多个脑白质神经纤维束微观结构受损,且与认知功能改变相关。

一种新的评估脑白质纤维形态变化的长度特征构建

基于弥散张量成像(DTI)数据可对全脑白质纤维进行三维呈现。当前对脑白质纤维的形态分析已用于研究在发育过程或病理情况下纤维形态的变化。本研究提出了一种新的逐脑白质纤维上点累加的欧氏空间距离表征其长度的特征,并进一步采用人类连接组计划(HCP)数据集中的50例样本从两个方面探究该特征稳定性。其一,不同纤维跟踪算法重建出的脑白质纤维对特征的影响;其二,同一种纤维跟踪算法下不同的脑白质纤维根数对特征的影响。纳入HCP数据集中的254例被试,运用该特征采用基于体素的分析(VBA)方式初步探究性别对脑白质纤维形态的影响。通过类内相关性系数(ICC)模型的计算发现,在两种纤维跟踪算法重建出的总体纤维长度比较接近的情况下,颅内绝大部分体素对应特征值的ICC在0.4以上。此外,同一种纤维跟踪算法下不同的脑白质纤维根数对特征的影响甚微,颅内体素对应特征值的ICC集中在0.8以上。性别对脑白质纤维长度影响的分析结果发现,相比于男性,女性在丘脑、穹窿、小脑中脚和苍白球区域的脑白质纤维长度特征值显著偏高;男性在右侧直回和右侧苍白球区域特征值显著高于女性。所提出的脑白质纤维长度特征丰富了脑白质纤维形态分析方法,可用于研究脑发育和脑相关的疾病。

阻塞性睡眠呼吸暂停患者脑白质及认知功能损害的扩散磁共振成像研究进展

阻塞性睡眠呼吸暂停(obstructive sleep apnea, OSA)是一种全球性的睡眠呼吸障碍疾病,特征是间歇性低氧血症、高碳酸血症、微觉醒和睡眠碎片化,会导致大脑在结构和功能方面发生改变,现已有很多研究表明OSA是认知功能损害的重要因素。扩散磁共振成像(diffusion magnetic resonance imaging, dMRI)通过测量水分子在组织中的扩散特性来获取有关组织微结构的详细信息,在检测组织微结构的病理变化方面具有极高的敏感度和特异度,尤其是在白质纤维病变的诊断中非常敏感。近年来,dMRI快速兴起,在OSA脑白质及认知功能损害的研究中得到了广泛应用。本文对OSA患者脑白质及认知功能损害的dMRI研究进展进行综述,多序列地分析OSA患者脑白质扩散参数的变化,进一步探讨OSA神经病理改变与认知功能损害的联系,从而为诊断OSA患者认知功能损害提供神经影像学依据。

静脉溶栓对脑梗死合并脑白质病变发生认知障碍的风险及疗效分析

目的 分析脑梗死合并脑白质病变(WML)患者静脉溶栓后认知障碍的发生风险及疗效。方法 回顾性分析静脉溶栓治疗的220例脑梗死合并WML患者临床资料。根据静脉溶栓治疗后认知功能情况分为障碍组(n=53)和无障碍组(n=167)。经多因素logistic回归分析,明确影响脑梗死合并WML患者静脉溶栓后认知功能的危险因素。结果 障碍组患者年龄≥60岁、卒中量表(NIHSS)评分≥9分、中度或重度WML占比及血清水通道蛋白(AQP4)水平高于无障碍组,miR-29b表达量低于无障碍组(P<0.05)。ROC曲线分析显示,血清miR-29b、AQP4均能预测脑梗死合并WML溶栓治疗后认知功能障碍的发生,曲线下面积分别为0.842、0.840(P<0.05)。经多因素logistic回归分析显示,年龄≥60岁、中度或重度WML、NIHSS评分≥9分、miR-29b表达量<0.895、AOP4水平≥33.695μg/L为脑梗死合并WML溶栓治疗后认知功能障碍的危险因素。结论 脑梗死合并WML静脉溶栓后认知功能障碍受年龄、WML程度、NIHSS评分、miR-29b表达量、AQP4水平的影响。

腔隙性脑梗死患者认知功能障碍与颅脑MRI显示脑白质变化的关系

目的:分析腔隙性脑梗死患者认知功能障碍与颅脑磁共振成像(MRI)显示脑白质变化的关系。方法:选取2021年1月—2023年12月广西壮族自治区江滨医院收治的98例腔隙性脑梗死患者作为研究对象,均接受MRI检查,并采用简明精神状态检查量表(MMSE)及蒙特利尔认知功能评估量表(MoCA)评估患者认知功能,并依据MRI检查结果将患者分组,比较不同分组患者临床资料,并采用Spearman相关性分析腔隙性脑梗死MRI脑白质变化与上述量表评分的关系。结果:98例患者经MRI检查,依据脑白质病变分级标准,0级19例(0级组),1级26例(1级组),2级30例(2级组),3级23例(3级组)。四组临床资料比较,差异无统计学意义(P>0.05)。四组MMSE评分、MoCA评分比较,差异有统计学意义(P<0.05);Spearman相关性分析显示,腔隙性脑梗死患者脑白质病变程度与MMSE评分、MoCA评分呈负相关(r=-0.823、-0.808,P<0.05)。结论:腔隙性脑梗死患者认知功能障碍与其脑白质病变有关,相关认知功能评分与脑白质病变严重程度呈负相关,临床可依据脑白质病变情况对患者认知功能损害进行预估。

脑小血管病总负荷与急性缺血性脑卒中的相关研究进展

急性缺血性卒中是病死率、致残率较高的疾病之一,而静脉溶栓及血管内治疗是目前临床治疗该病的有效方法。脑小血管病的概念被提出后经过一系列研究发现,其与急性缺血性脑卒中治疗预后具有显著的相关性。特别是脑小血管病总负荷评分能够更好评估脑小血管病对大脑整体功能的影响情况,国内外已对其在急性缺血性脑卒中静脉溶栓及血管内治疗预后方面进行着各种层面的相关研究,旨在对急性缺血性卒中患者病情进展进行预判并提前干预,以降低患者致残率和病死率。本文着重对脑小血管病总负荷与急性缺血性脑卒中治疗预后的相关研究进行综述。

Pulsed arterial spin labeling effectively and dynamically observes changes in cerebral blood flow after mild traumatic brain injury

Cerebral blood flow is strongly associated with brain function, and is the main symptom and diagnostic basis for a variety of encephalopathies. However, changes in cerebral blood flow after mild traumatic brain injury remain poorly understood. This study sought to observe changes in cerebral blood flow in different regions after mild traumatic brain injury using pulsed arterial spin labeling. Our results demonstrate maximal cerebral blood flow in gray matter and minimal in the white matter of patients with mild traumatic brain injury. At the acute and subacute stages, cerebral blood flow was reduced in the occipital lobe, parietal lobe, central region, subcutaneous region, and frontal lobe. Cerebral blood flow was restored at the chronic stage. At the acute, subacute, and chronic stages, changes in cerebral blood flow were not apparent in the insula. Cerebral blood flow in the temporal lobe and limbic lobe diminished at the acute and subacute stages, but was restored at the chronic stage. These findings suggest that pulsed arterial spin labeling can precisely measure cerebral blood flow in various brain regions, and may play a reference role in evaluating a patient＇s condition and judging prognosis after traumatic brain injury.

Characteristics of diffusion-tensor imaging for healthy adult rhesus monkey brains

Diffusion-tensor imaging can be used to observe the microstructure of brain tissue. Fractional ani- sotropy reflects the integrity of white matter fibers. Fractional anisotropy of a young adult brain is low in gray matter, high in white matter, and highest in the splenium of the corpus callosum. Thus, we selected the anterior and posterior limbs of the internal capsule, head of the caudate nucleus, semioval center, thalamus, and corpus callosum （splenium and genu） as regions of interest when using diffusion-tensor imaging to observe fractional anisotropy of major white matter fiber tracts and the deep gray matter of healthy rhesus monkeys aged 4-8 years. Results showed no laterality dif- ferences in fractional anisotropy values. Fractional anisotropy values were low in the head of cau- date nucleus and thalamus in gray matter. Fractional anisotropy values were highest in the sple- nium of corpus callosum in the white matter, followed by genu of the corpus callosum and the pos- terior limb of the internal capsule. Fractional anisotropy values were lowest in the semioval center and posterior limb of internal capsule. These results suggest that fractional anisotropy values in major white matter fibers and the deep gray matter of 4-8-year-old rhesus monkeys are similar to those of healthy young people.