T2?值在健康成年人脑铁含量与年龄的相关性分析

目的：采用3.0T ESWAN 定量测量健康成年人额叶白质区及灰质核团的 T2?值,探讨额叶白质区及灰质核团与年龄的相关性。方法收集年龄20~85岁的157例健康成年人进行 MRI 常规及 ESWAN 扫描,按其年龄段分为6组。A 组：20~29岁;B 组：30~39岁;C 组：40~49岁;D 组：50~59岁;E 组：60~69岁;F 组：≥70岁。经后处理在 T2?图像上分别测量左右侧额叶白质区、红核、黑质网状带、黑质致密带、尾状核头、壳核、苍白球和丘脑的 T2?值,分析 T2?值与年龄的相关性。结果健康成年人在黑质网状带、苍白球的T2?值最低,额叶白质区的T2?值最高。红核、壳核、苍白球、尾状核头和丘脑的T2?值在部分年龄段间有统计学意义(P <0.05),有一定规律性。而黑质网状带、黑质致密带、额叶白质区的 T2?值在不同年龄段间差异无统计学意义(P >0.05)。红核、黑质网状部、黑质致密部、壳核、苍白球、尾状核头的 T2?值与年龄呈明显负相关(r 值=-0.258、-0.229、-0.231、-0.584、-0.320、-0.437, P 值均<0.001),而丘脑、额叶白质区的 T2?值与年龄呈正相关(r 值=0.319、0.161,P <0.001及0.05)。结论ESWAN 能清晰显示脑内核团的结构,准确评估脑内的铁含量和随年龄变化的规律。     

正常人脑核团铁含量分布及年龄相关性MR磁敏感成像初步研究

目的 利用3.0T MRI的ESWAN相位值评估正常人脑各核团的铁含量,观察其分布规律及随年龄变化的趋势.方法 正常志愿者30例,按年龄分3组:第一组,11~30岁,共11例;第二组,31~60岁,共13例;第三组,61岁以上,共6例.各组均行MRI检查,包括横断位T2WI、ESWAN等,检查结束后手工绘出各核团的感兴趣区,测量其ESWAN相位值,采用单因素方差分析(LSD法)、配对t检验评价各核团间、核团的左右两侧间及各年龄组间的统计学差异.结果 ①苍白球、壳核、尾状核、黑质及红核等核团的均值分别为-0.192 0±0.066 92,-0.139 3±0.072 50,-0.149 4±0.041 73,-0.191 0±0.078 89,-0.128 6±0.077 82.②苍白球和黑质与壳核、红核及尾状核之间的差异性分别有统计学意义.③除红核外其余核团左右两侧均存在统计学差异.④壳核及尾状核在3个年龄组存在统计学差异(P＜0.05).结论 ESWAN相位值可评估苍白球、壳核、尾状核、黑质及红核等核团间、核团的左右两侧的铁含量的差异性及随年龄变化铁含量的变化趋势.     

SWI 测量脑铁在帕金森病病情评估中的应用价值

目的：探讨磁敏感加权成像(SWI)测量脑铁在帕金森病(PD)的诊断以及病情评估中的应用价值。方法30例经临床诊断为PD 的患者行颅脑磁共振常规序列和 SWI 序列扫描,PD 患者病情评估采用统一帕金森病评定量表(UPDRS)。在 SWI 序列相位图上手动测量患者黑质、红核、尾状核、苍白球和壳核的相位值,分析以上感兴趣区(ROI)核团的相位值与 UPDRS 评分的相关性。结果ROI 核团病重侧与病轻侧的相位值比较无差异(黑质,P =0.120;红核,P =0.402;尾状核,P =0.196;苍白球,P =0.616;壳核, P =0.985);PD 患者 UPDRS Ⅲ评分分别与黑质、尾状核和苍白球的相位值呈负相关(黑质-UPDRS Ⅲ：r =-0.407,P =0.026;尾状核-UPDRS Ⅲ：r=-0.424,P=0.02;苍白球-UPDRS Ⅲ：r=-0.363,P=0.048);黑质相位值与 UPDRS Ⅴ的分期呈负相关(r=-0.373, P =0.043);尾状核相位值与 UPDRSⅠ的评分呈负相关(r=-0.367,P =0.046);苍白球相位值与 UPDRS Ⅲ中的步态障碍评分呈负相关(r=-0.411,P =0.024),而其余核团的相位值与 UPDRS 评分不相关。结论SWI 可以定量评估 PD 患者脑部核团的异常铁沉积,为 PD 的临床诊断和病情评估提供参考。     

脑铁含量和T2弛豫时间的关系

探讨脑铁含量与T2弛豫时间的关系。材料与方法选择15例意外死亡尸体脑,除外脑外伤、脑梗塞、脑肿 瘤、神经和精神系统疾病,测量双侧苍白球、尾状核、丘脑、黑质、红核、齿状核及双侧额、枕、颞叶白质T2弛豫时间(SE序 列T1WITR/TE500/40ms;T2WITR/TE2700/80ms)和铁含量,对脑铁含量与T2弛豫时间行相关性分析。结果灰质核团 T2弛豫时间随脑铁含量增加而缩短,脑白质T2弛豫时间无变化趋势。灰质核团(除苍白球)r值在-0.6928～-0.9440之 间,苍白球和白质区r值在-0.0418～-0.3722之间。结论(1)苍白球区T2弛豫时间易偏移不宜作为脑铁MRI研究区 域;(2)脑灰质核团的T2弛豫时间下降主要与铁沉积有关,脑白质T2弛豫时间与多种因素有关。     

7.0T磁敏感加权成像对脑铁含量测定的初步研究

目的:对比7.0T与3.0T磁敏感加权成像铁含量测量的差异,并积累超高场磁共振神经成像经验。方法:50例老年志愿者(年龄52～68岁,男36例,女14例)分别在7.0T和3.0T磁共振成像系统上行常规颅脑磁共振成像及磁敏感加权成像(SWI)。对比不同场强下的图像质量,测量受试者双侧苍白球、壳核、尾状核头、黑质、红核以及丘脑的大小及相位值,同时测量受试者各核团铁含量。结果:①幅度图上,7.0T影像能提供更多细节,并可区分核团亚分区(P<0.05);②7.0T下可辨识的ROI范围较3.0T下的略大,不同场强的各核团ROI范围差异有统计学意义(P<0.05);③除苍白球外,壳核、尾状核头、黑质、红核及丘脑3.0T和7.0T比较,铁含量测量值差异均有统计学意义(P<0.05)。结论:7.0T磁共振磁敏感成像可提供更多解剖细节,SWI脑铁含量测量值与3.0T可能存在差异。     

帕金森病脑铁沉积的定量研究

目的通过磁敏感成像定量研究帕金森病脑铁沉积。方法帕金森病患者31例和健康对照组34例行磁共振检查,扫描序列包括常规MRI平扫和SWI成像,测量双侧黑质、红核、丘脑、基底核及额叶白质的CP值,分析PD组与对照组之间CP值的差异并将PD组各个部位的CP值与各项量表的评分进行相关性分析。结果对照组左右侧丘脑和额叶白质CP值有统计学差异(P0.05),PD组左右侧尾状核和额叶白质CP值有统计学差异(P0.05),PD组左侧红核CP值低于对照组,二者之间的差异有统计学意义(P0.05);PD组依照ADL评分、HAMD评分和MOCA评分分组,功能障碍组左侧黑质CP值低于ADL正常组且差异有统计学意义(P0.05);中度抑郁组左额叶白质CP值低于轻度抑郁组和无抑郁组且差异有显著性(P0.05);右侧苍白球和左额叶白质CP值在不同MOCA评分组之间有统计学差异(P0.05),重度认知功能障碍组的CP值最低。相关性检验中,左侧黑质CP值与ADL评分呈负相关(r=-0.492,P0.05)左额叶白质的CP值与HAMD评分呈负相关(r=-0.915,P0.05),左侧黑质CP值(r=0.428)、左额叶白质CP值(r=0.391)与MOCA评分呈正相关(P0.05)。左额叶白质CP值与MMSE评分呈正相关(r=0.428,P0.05)。结论通过SWI可以定量研究帕金森病患者脑铁沉积,并且分析脑内异常铁沉积与认知功能障碍和抑郁的关系。     

早期帕金森病扩散张量成像的初步研究

目的 评价MRI扩散张量成像(DTI)技术在早期帕金森病(PD)中的诊断价值.资料与方法 对30名早期PD患者和30例匹配的健康老年对照组的黑质-纹状体区进行了常规MR平扫和DTI扫描,对双侧黑质-纹状体纤维环路穿越的部位:黑质致密部、底丘脑核、苍白球、壳核、尾状核连续层面的FA值和DCavg值进行测量和统计分析.结果 PD组黑质致密部、黑质致密部与底丘脑核之间部位的FA值显著低于对照组(P值<0.05).苍白球、壳核、尾状核等部位的FA值和DCavg值与对照组相比无显著差异.结论 DTI能无创性定量测量早期PD黑质.纹状体区病变的FA值和DCavg值,是对早期PD黑质.纹状体区进行定量评估的一种敏感的研究手段.     

肝硬化患者脑改变的磁化传递成像定量研究

目的 利用磁化传递成像（MTI）评价肝硬化患者是否存在异常的脑改变,探讨其与静脉血氨值、苍白球指数（GPI）及神经心理学测试之间的相关性. 资料与方法 48例肝硬化患者和30名健康志愿者,在T1WI上分别测量壳核和苍白球的信号值计算GPI.在MTI中将感兴趣区（ROI）置于双侧顶叶白质、额叶白质、枕叶白质、尾状核头、壳核、苍白球、丘脑,计算右侧各部位的磁化传递率（MTR）. 结果 （1）患者组各部位的MTR明显低于正常对照组,差异有统计学意义（P均＜0.001）.苍白球的MTR降低最明显,约9%.（2）对于Child分级和肝性脑病（HE）分级,顶叶、额叶、壳核、苍白球及枕叶白质的MTR差异均有统计学意义（P均＜0.05）,两两比较后显示,上述部位的MTR在Child A和B级、A和C级之间差异有统计学意义,B和C级之间差异则无统计学意义;在肝硬化、轻微型肝性脑病（MHE）及HE 3组患者之间差异无统计学意义.（3）顶叶、额叶、壳核、苍白球及枕叶的MTR、GPI指标与Child分级呈负相关（P均＜0.05）,而仅苍白球的MTR与HE分级间呈负相关（r＝-0.291,P＝0.045）.（4）Pearson相关分析显示,顶叶、额叶、壳核、苍白球及枕叶的MTR、GPI与血氨之间没有相关性,与各神经心理学测试之间有相关关系（P均＜0.05）. 结论 肝硬化患者存在轻度脑水肿,其有随Child分级加重的趋势,由此,可部分解释肝硬化患者的认知功能改变.     

三维增强T2*加权血管成像量化多发性硬化脑铁沉积的研究

目的 探讨三维增强T2*加权血管成像(ESWAN)相位值(phase)及有效横向弛豫率值(R2*)对多发性硬化(MS)患者深部灰质核团铁沉积的诊断价值,并分析测量值与扩展型残疾状态评分(EDSS)、病程相关性.方法 22例临床确诊MS患者及与之性别、年龄及教育程度相匹配的22名健康对照组行常规MRI和ESWAN扫描.测量患者及对照组深部灰质核团(双侧丘脑、尾状核头、壳核、苍白球、红核、黑质)phase值及R2*值.详细记录每例患者病程时间及EDSS评分.结果 (1)MS患者双侧深部灰质核团phase值均低于对照组,其中双侧尾状核头、壳核、红核及黑质与对照组比较差异具有统计学意义(P＜0.05).(2)MS患者双侧各个灰质核团R2*均高于对照组,差异均具有统计学意义(P＜0.05).(3)MS患者各深部灰质核团phase值、R2*值与EDSS评分、临床病程均无明显相关性(P＞0.05).结论 ESWAN序列多种测量值均能定量显示MS患者脑深部灰质核团明显铁质含量增多,有助于了解MS病理机制、研究颅内铁沉积与患者临床表现的相关性.     

急性一氧化碳中毒脑损伤的磁共振扩散张量成像

目的：利用磁共振扩散张量成像(DTI )评估急性一氧化碳(CO)中毒患者的脑结构损伤情况。方法25例急性(5.0 d±1.44 d) CO 中毒患者和37例性别、年龄、利手、受教育程度匹配的健康志愿者进行 DTI 扫描,获得扩散张量纤维束成像(DTT)图像,并分别测量双侧小脑半球(齿状核)、黑质、海马、额叶白质(侧脑室前角前下方、侧脑室体部上方)、尾状核头、苍白球、丘脑、内囊前肢、内囊后肢、枕叶白质(视中枢)、顶叶白质(侧脑室体部上方)及胼胝体膝部、压部共26个感兴趣(ROI)的各向异性分数(FA)值和表观扩散系数(ADC)值,进行组间配对 t 检验。结果病患组双侧苍白球、双侧内囊前肢、双侧黑质、右侧小脑、左侧额叶下部白质、右额叶上下部白质、胼胝体膝部的 FA 值显著低于对照组(P <0.05)。病患组右侧黑质、左侧苍白球的 ADC 值显著降低(P <0.05),病患组右额叶上下部白质及双侧枕叶白质 ADC 值显著升高(P <0.05)。结论急性 CO 中毒患者广泛脑微结构受损,提示脑微结构的原发损伤可能是 CO 中毒迟发性脑病潜在的病理生理基础。     

Interregional variation of longitudinal relaxation rates in human brain at 3.0 T: relation to estimated iron and water contents.

In a study of interregional variation of the longitudinal relaxation rate (R(1)) in human brain at 3 T, R(1) maps were acquired from 12 healthy adults using a multi-slice implementation of the T one by multiple readout pulses (TOMROP) sequence. Mean R(1) values were obtained from the prefrontal cortex (0.567 +/- 0.020 sec(-1)), caudate head (0.675 +/- 0.019 sec(-1)), putamen (0.749 +/- 0.023 sec(-1)), substantia nigra (0.873 +/- 0.037 sec(-1)), globus pallidus (0.960 +/- 0.034 sec(-1)), thalamus (0.822 +/- 0.027 sec(-1)), and frontal white matter (1.184 +/- 0.057 sec(-1)). For gray matter regions other than the thalamus, R(1) showed a strong correlation (r = 0.984, P < 0.0001) with estimated regional nonheme iron concentrations ([Fe]). These R(1) values also showed a strong correlation (r = 0.976, P < 0.0001) with estimates of 1/f(w) obtained from MRI relative proton density measurements, where f(w) represents tissue water content. When white matter is included in the consideration, 1/f(w) is a better predictor of R(1) than is [Fe]. An analysis based on the fast-exchange two-state model of longitudinal relaxation suggests that interregional differences in f(w) account for the majority of the variation of R(1) across gray matter regions. Magn Reson Med 45:71-79, 2001.     

Relationship between brain R2 and liver and serum Iron concentrations in elderly men

Studies of iron overload in humans and animals suggest that brain iron concentrations may be related in a regionally specific way to body iron status. However, few quantitative studies have investigated the associations between peripheral and regional brain iron in a normal elderly cohort. To examine these relationships, we used MRI to measure the proton transverse relaxation rate (R₂) in 13 gray and white matter brain regions in 18 elderly men (average age, 75.5 years) with normal cognition. Brain R₂ values were compared with liver iron concentrations measured using the FerriScan® MRI technique and serum iron indices. R₂ values in high‐iron gray matter regions were significantly correlated (positively) with liver iron concentrations (globus pallidus, ventral pallidum) and serum transferrin saturation (caudate nucleus, globus pallidus, putamen) measured concurrently with brain R₂, and with serum iron concentrations (caudate nucleus, globus pallidus) measured three years before the current study. Our results suggest that iron levels in specific gray matter brain regions are influenced by systemic iron status in elderly men. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.     

Deep gray matter hypointensity patterns with aging in healthy adults: MR imaging at 1.5 T

The authors studied a carefully screened pool of healthy adult volunteers aged 20-80 years, so that a normal brain deep gray matter hypointensity map, as detectable on routine spin-echo magnetic resonance (MR) images, could be formulated. Previous MR imaging studies about brain iron reported findings either in children only or in adults, all of whom had suspected central nervous system disease. The results showed that (a) areas of hypointensity in the red nucleus, substantia nigra, and dentate nucleus were relatively unchanged throughout all age groups; (b) the globus pallidus showed an increased volume of hypointensity in the middle-aged and elderly population compared with that in the young adult; (c) the putamen was hypointense only in the elderly age group; and (d) hypointensity was never seen in the thalamus or caudate nucleus in any subject, regardless of age. In cases in which these patterns are not observed in patients suspected to have central nervous system disease, the presence of such disease should be considered.     

T2 values in the human brain: comparison with quantitative assays of iron and ferritin

Magnetic resonance (MR) imaging with a whole-body imager was performed in 10 fresh, unfixed whole human brains selected randomly from cadavers. All subjects were neurologically intact before death. T2 time constants were measured within the caudate nucleus, putamen, globus pallidus, cortical gray matter, subcortical white matter, and optic radiation. These regions were then excised, and T2 values were measured again with a 1.5-T MR spectrometer. Quantitative assays of iron, ferritin, and protein from these areas were then performed. Iron concentration varied significantly among brain regions, whereas ferritin and protein concentrations were constant among brain regions and among individuals. Neither iron nor ferritin concentration showed any consistent correlation with T2 values. Histologic examination of brain micro-sections with iron- and ferritin-specific stains of demonstrated poor correlation with biochemical assays of ferritin and iron concentrations. Results indicate that T2 values correlate poorly with iron and ferritin concentrations found in neurologically intact brains.     

人脑标本不同区域多巴胺转运体分布的免疫放射自显影研究

目的 定量分析人脑标本不同区域多巴胺转运体(DAT)的免疫反应强度,为神经影像检查DAT变化的参照区选择提供依据.方法 取自8例男性尸脑标本的脑组织块经石蜡包埋切片后,以免疫放射自显影显示黑质、壳及尾状核、扣带回、额叶、枕叶和小脑皮质的DAT免疫反应强度.结果 所观察的脑区中,DAT免疫反应强标记主要分布在黑质、尾状核及壳,小脑皮质标记最弱.定量分析发现,小脑皮质的DAT免疫反应强度分别为额叶、扣带回及枕叶的1/3.50、1/3.72、1/1.28,仅为黑质、尾状核、壳的1/8.33、1/11.67、1/8.56.结论 小脑皮质在所检脑区中DAT含量最低,可作为神经影像检查DAT变化的参照区.     

Normal deposition of brain iron in childhood and adolescence: MR imaging at 1.5 T

Magnetic resonance (MR) images of the brain in 285 patients between the ages of 2 and 25 years were retrospectively studied to determine the appearance of brain iron accumulation. The globus pallidus, red nucleus, substantia nigra, and dentate nucleus were evaluated with long TR/TE (repetition time/echo time) spin-echo sequences and staged. All four regions in most patients were initially hyperintense compared with white matter (stage I) before becoming isointense (stage II) and subsequently hypointense (stage III). The globus pallidus was the first to reach stage III, the red nucleus and substantia nigra were next, and the dentate nucleus was last. In general, decreased signal intensity (stage III) was not seen in these regions in patients less than 10 years old; in most patients it was seen by age 25 years. The dentate nucleus decreased in signal intensity more slowly and inconsistently; only one-third of patients had reached stage III by age 25 years. The temporal sequence of normal iron deposition as detected with MR imaging is helpful not only in the diagnosis of known iron-deposition diseases but also in the detection of iron-related pathologic changes.     

In vivo MR evaluation of age-related increases in brain iron.

PURPOSETo assess the validity of an MR method of evaluating tissue iron.METHODSThe difference between the transverse relaxation rate (R2) measured with a high-field MR instrument and the R2 measured with a lower field instrument defines a measure termed the field-dependent R2 increase (FDRI). Previous in vivo and in vitro studies indicated that FDRI is a specific measure of tissue iron stores (ferritin). T2 relaxation times were obtained using two clinical MR instruments operating at 0.5 T and 1.5 T. T2 relaxation times were measured in the frontal white matter, caudate nucleus, putamen, and globus pallidus of 20 healthy adult male volunteers with an age range of 20 to 81 years. R2 was calculated as the reciprocal of T2 relaxation time. These in vivo MR results were correlated with previously published postmortem data on age-related increases of nonheme iron levels.RESULTSThe FDRI was very highly correlated with published brain iron levels for the four regions examined. In the age range examined, robust and highly significant age-related increases in FDRI were observed in the caudate and putamen. The correlations of age and FDRI in the globus pallidus and white matter were significantly lower and did not have statistical significance.CONCLUSIONSThe data provide additional evidence that FDRI is a specific measure of tissue iron stores. The data also show that age-related increases in tissue iron stores can be quantified in vivo despite significant age-related processes that oppose the increase in R2 caused by iron. These results are relevant to the investigation of neurodegenerative processes in which iron may catalyze toxic free-radical reactions.     

Interhemispheric asymmetry of brain diffusivity in normal individuals: a diffusion-weighted MR imaging study

BACKGROUND AND PURPOSE: Previous neuroimaging studies have suggested asymmetries in brain diffusivity may exist. The purpose of this study was to assess whether water diffusivity in deep gray matter structures shown by diffusion-weighted (DW) imaging differs between the right and left cerebral hemispheres in normal individuals. METHODS: Brain MR imaging was obtained in 23 healthy volunteers. A multisection image without diffusion weighting, and images with weighting applied in the read, phase, and section directions with a b-factor of 1000 s/mm(2) were collected. Diffusivity was computed separately in each direction, and the results were averaged to form mean diffusivity maps. Quantitative diffusivity values were obtained from the globus pallidus, putamen, caudate, thalamus, white matter, and CSF by using a standardized region of interest template. Interhemispheric differences were assessed by using a paired sample t test. RESULTS: Mean diffusivity was higher in the: left (mean +/- SD: 0.689 x 10(-3)+/- 0.069 x 10(-3)mm(2)/s) versus right (0.642 x 10(-3)+/- 0.071 x 10(-3)mm(2)/s) caudate (% difference, P value: 7.0%, P = .001); right (0.745 x 10(-3)+/- 0.053 x 10(-3)mm(2)/s) versus left (0.706 x 10(-3)+/- 0.050 x 10(-3)mm(2)/s) globus pallidus (5.2%, P < .001); left (0.720 x 10(-3)+/- 0.059 x 10(-3)mm(2)/s) versus right (0.674 x 10(-3)+/- 0.052 x 10(-3)mm(2)/s) putamen (6.4%, P < .001); right (0.750 x 10(-3)+/- 0.040 x 10(-3)mm(2)/s) versus left (0.716 x 10(-3)+/- 0.031 x 10(-3)mm(2)/s) thalamus (4.5%, P < .001). No significant right versus left difference was seen in the CSF (P = .291), anterior frontal white matter (P = .834), or centrum semiovale (P = .320). CONCLUSION: Gray matter diffusivity may differ between hemispheres of the brain in healthy individuals. Analysis of deep gray matter lesions requires caution, as statistically significant interhemispheric differences may not always be indicative of disease.