Alzheimer病和健康老人的脑容积和脑代谢变化的MRI和MRS分析研究

目的：探讨Ａｌｚｈｅｉｍｅｒ病（ＡＤ）患者与健康对照组脑组织容积和脑组织内Ｎ－乙酰天门冬氨酸（ＮＡＡ）、胆碱（Ｃｈｏ）及肌－肌醇（Ｍｉ）的特征及异同。材料和方法：对临床确诊的１３例ＡＤ患者和１３例健康老人进行ＭＲＩ脑组织分割分析，定量研究两组脑实质容积的变化。对两组各１１例同时进行了磁共振波谱检查，定量分析两组的ＮＡＡ、Ｃｈｏ及Ｍｉ的水平。结果：ＭＲＩ脑组织分割分析显示ＡＤ组较对照组有明显的脑灰质丢失，两组脑白质的容积无明显差异。磁共振波谱分析（ＭＲＳ）显示ＡＤ组ＮＡＡ水平较对照组降低，Ｍｉ水平较对照组升高，两组的Ｃｈｉ水平无显著差异。结论：脑组织分割分析能够准确的反映ＡＤ患者脑灰质萎缩的范围；ＭＲＳ能够准确提供ＡＤ患者脑部ＮＡＡ、Ｃｈｏ和Ｍｉ的代谢情况，两者结合有助于ＡＤ的诊断。     

Alzheimer型痴呆的CT与MRI研究

目的验证海马萎缩在Ａｌｚｈｅｉｍｅｒ型痴呆（ＤＡＴ）中作为一种预测标志的价值，为临床提供辅助诊断方法。材料与方法选３０名受检者全部通过简易精神状态检查（ｍｉｎｉ－ｍｅｎｔａｌｓｔａｔｅｅｘ－ａｍｉｎａｔｉｏｎ，ＭＭＳＥ），ＣＴ扫描观察海马周围裂的变化，并测量海马内侧的脑脊液池（ＨＣＳＦ），即测量环池内侧边到颞叶内侧边之间的距离。选其中１３名行ＭＲＩ扫描测量海马结构（ＨＦ）体积。结果在正常人中区分Ａｌｚｈｅｉｍｅｒ型痴呆病人最敏感的测量是ＭＭＳＥ，最特异性的测量是ＨＣＳＦ。ＨＦ体积与ＭＭＳＥ在正常组中无相关性，而在ＤＡＴ组中有显著的相关关系。结论我们的研究表明：海马周围裂的扩大及海马体积缩小对临床诊断ＤＡＴ是一个有用的放射学标志     

脑弥漫性轴索损伤的实验性研究

目的：探讨急性期脑弥漫性轴索损伤（ｄｉｆｕｓｅａｘｏｎａｌｉｎｊｕｒｙ，ＤＡＩ）的病理改变及与ＣＴ、ＭＲＩ特征的相关性。材料和方法：本实验应用自行设计的“损伤加速机”对２２只猫按两种大小不等的角加速度损伤，首次应用猫建立了ＤＡＩ动物模型。结果：急性期（７２小时内）ＤＡＩ的病理表现为轴索的扭曲、肿胀、断裂及间质水肿。ＣＴ可见弥漫性脑肿胀、皮层下及脑深部小出血灶、蛛网膜下腔及脑室内出血。ＭＲＩ可见弥漫性脑肿胀（脑白质在Ｔ１加权像上信号减低及脑沟、脑裂消失）和单发或多发脑白质小灶性损伤（脑白质在Ｔ２加权像上可见单发或多发小灶性高信号影）。离体脑白质磁共振波谱（ｍａｇｎｅｔｉｃｒｅｓｏｎａｎｃｅｓｐｅｃｔｒｏｓｃｏｐｙ，ＭＲＳ）检查发现损伤后脑白质游离水相对含量明显高于正常对照组，损伤后结合水相对含量明显低于正常对照组，二者Ｔ１值均较正常对照组延长。结论：ＭＲＩ对ＤＡＩ的诊断价值明显优于ＣＴ。通过对ＣＴ、ＭＲ图像分析，可以间接推测ＤＡＩ的病理改变及程度，有利于做出正确、全面的诊断和制定恰当的治疗方案。     

肝脏Gd-DTPA快速动态增强MRI的临床应用──较小HCC与FNH的动态增强表现

目的：运用梯度回波（ＧＲＥ）的快速场回波（ＦＦＥ）技术，对２０例肝肿块进行Ｇｄ－ＤＴＰＡ动态增强，旨在探明不同肿块的增强规律，提高肝肿块的诊断和鉴别诊断能力。材料与方法：选取经过其他影像学检查未确诊的２０例肝肿块，作常规自旋回波（ＳＥ）平扫后作Ｇｄ－ＤＴＰＡＦＦＥ序列快速动态增强扫描，分别测量病灶信号强度（ＳＩｌｅｓｉｏｎ），灶周正常肝脏信号强度（ＳＩｌｉｖｓｒ），背景噪声信号强度和标准差（ＳＩｎｏｉｓｅｃ±ｓ），计算不同病变不同时相的肝－病灶对比噪声比（Ｃ／Ｎ），描出不同肿块（本文只评价其中手术病理证实的１３例肿块，包括肝细胞癌１０例，局灶性结节增生３例的时间－病灶Ｃ／Ｎ曲线。结果：ＨＣＣ与ＦＮＨ两者曲线较接近（包括强化峰值和升降坡度），但在增强早期，ＨＣＣ的Ｃ／Ｎ值高于ＦＮＨ，３分钟以后二者强化值均下降，且ＦＮＨ的Ｃ／Ｎ值大于０，ＨＣＣ的Ｃ／Ｎ值小于０，此差异可持续１５～２０分钟。结论：不同的肝肿块，动态增强后的时间－Ｃ／Ｎ曲线不同，对ＨＣＣ及ＦＮＨ而言，增强早期（１分钟以内）及３分钟以后曲线差异较大，最有助于鉴别诊断。动态增强ＭＲ成像可作为肝脏常规ＳＥ序列成像的一种有效的补充方法。     

高压氧在小鼠Lewis肺癌化学治疗中增效作用的研究(论著)

目的：探讨高压氧（ＨＢＯ）对荷Ｌｅｗｉｓ肺癌小鼠在化学治疗中的增效作用及其机理。方法：２７０只荷Ｌｅｗｉｓ肺癌的Ｃ５７小鼠被随机等分为空气对照组、高压氮氧组、ＨＢＯ组、ＨＢＯ－丝裂霉素组、ＨＢＯ－环磷酰胺组、ＨＢＯ－ＳＯＤ组、丝裂霉素组、环磷酰胺组和ＳＯＤ组共９个组。对Ｌｅｗｉｓ肺癌小鼠使用化疗结合ＨＢＯ疗法。采用电子自旋共振（ＥＳＲ）技术直接检测Ｌｅｗｉｓ肺癌组织中的氧自由基（ＯＦＲ）含量，并且应用分光光度法测定其脂质过氧化物丙二醛（ＭＤＡ）的含量，同时对各组动物荷瘤的体积、重量、坏死率及小鼠致死率进行了观察。结果：ＨＢＯ组、ＨＢＯ－丝裂霉素组及ＨＢＯ－环磷酰胺组的动物与相应的对照组相比，肺癌组织中的ＯＦＲ含量和ＭＤＡ含量均显著增高（Ｐ＜０．０５～０．００１）；荷瘤组织坏死率高，且坏死所需时间短；动物成活率高；肿瘤体积和重量也显著小于对照组（Ｐ＜０．０５～０．００１）。结论：荷Ｌｅｗｉｓ肺癌小鼠经ＨＢＯ暴露可以减缓荷瘤生长速度并加速癌细胞的坏死，丝裂霉素或环磷酰胺结合ＨＢＯ治疗能显著增强药物的抗肿瘤作用，减轻药物的副作用和延长小鼠的生命。     

正常中国成人MRI海马结构体积测定

目的讨论磁共振海马结构（ｈｉｐｐｏｃａｍｐａｌｆｏｒｍａｔｉｏｎ，ＨＦ）体积测量方法，制订正常成人ＨＦ体积范围。材料与方法５２例正常成人做垂直于ＨＦ长轴的倾斜冠状位自旋回波（ＳＥ）序列Ｔ１加权像，其中２５例还做相同位置的三维磁化准备快速梯度回波（ｔｈｒｅｅｄｉｍｅｎｓｉｏｎａｌｍａｇｎｅｔｉｚａｔｉｏｎｐｒｅ－ｐａｒｅｄｒａｐｉｄｇｒａｄｉｅｎｔｅｃｈｏ，３ＤＭＰＲＡＧＥ）序列Ｔ１加权像。体积测量后界定在后连合，手工勾画出ＨＦ边缘获得面积，并依此获得ＨＦ体积。结果正常成人ＨＦ体积与年龄无关，在性别、利手之间均无显著性差异，右侧下限为２．６２ｃｍ３，左侧为２．４８ｃｍ３。３ＤＭＰＲＡＧＥ序列较ＳＥ序列的对比度、对比噪声比、对比伪影比高，而两者信噪比无显著性差异。结论后连合作为ＨＦ体积测定后界较合适，ＨＦ正常值的制订有利于颞叶癫痫的定侧。３ＤＭＰＲＡＧＥ序列较ＳＥ序列用于ＨＦ体积测定更为优越     

L─ARGININE IMPROVES THE SPLANCHNIC VASODILATATION AND INTESTINAL BLOOD FLOW IN ENDOTOXEMIA

Ｌ┐ＡＲＧＩＮＩＮＥＩＭＰＲＯＶＥＳＴＨＥＳＰＬＡＮＣＨＮＩＣＶＡＳＯＤＩＬＡＴＡＴＩＯＮＡＮＤＩＮＴＥＳＴＩＮＡＬＢＬＯＯＤＦＬＯＷＩＮＥＮＤＯＴＯＸＥＭＩＡＸＩＡＯＮａｎ（肖南），ＣＨＥＮＨｕｉ－ｓｕｎ（陈惠孙），ＨＵＤｅ－ｙａｏ（胡德耀）ＬＵＳ...     

Alzheimer型痴呆的MRI初步研究

目的：探讨Ａｌｚｈｅｉｍｅｒ型痴呆（ＡＤ）患者脑部的ＭＲＩ表现特征和诊断价值。方法：对１０例ＡＤ患者和选择１０例性别、年龄相关且无阳性神经系统体征的老年人进行ＭＲＩ比较研究。测量两组的海马体积、钩间距、胼胝体面积和记录脑实质内有无异常信号。结果：１．ＡＤ组左、右侧平均海马体积明显小于对照组，且有统计学意义（Ｐ＜０．０５）；２．ＡＤ组平均钩间距大于对照组，并有统计学差异（Ｐ＜０．０５）；３．ＡＤ组胼胝体萎缩重于对照组；４．ＡＤ组Ｔ２ＷＩ图像上小斑状高信号（１７个）略多于对照组（１５个），两组无统计学差异（Ｐ＞０．０５）。结论：ＭＲＩ能准确地显示ＡＤ的脑部形态学改变，有助于ＡＤ的明确诊断     

EXPERIMENTAL STUDY OF GUNSHOT INJURY OF THESPINAL COKD：THEMECHANISMANDCLASSIFICATION

ＥＸＰＥＲＩＭＥＮＴＡＬＳＴＵＤＹＯＦＧＵＮＳＨＯＴＩＮＪＵＲＹＯＦＴＨＥＳＰＩＮＡＬＣＯＫＤ：ＴＨＥＭＥＣＨＡＮＩＳＭＡＮＤＣＬＡＳＳＩＦＩＣＡＴＩＯＮＳｉｕＳｈａｏ－ｔｉｎｇ肯少汀ＺｈａｎｇＬｉ－ｒｅｎ张立仁ＧｅＺｈｅｎ－ｓｈａｎ葛振山Ｃｈｅｎｇ...     

A Comparison in Healing of Skull Defect Repaired with Four Different Kinds of Graft Materials in Rabbits

ＡＣＯＭＰＡＲＩＳＯＮＩＮＨＥＡＬＩＮＧＯＦＳＫＵＬＬＤＥＦＥＣＴＲＥＰＡＩＲＥＤＷＩＴＨＦＯＵＲＤＩＦＦＥＲＥＮＴＫＩＮＤＳＯＦＧＲＡＦＴＭＡＴＥＲＩＡＬＳＩＮＲＡＢ┐ＢＩＴＳＤＩＮＧＺｈｅｎ－ｑｉ（丁真奇）１，ＴＡＮＦｕ－ｓｈｅｎｇ（谭富生）２，...     

Tissue segmentation of the brain in Alzheimer disease.

PURPOSETo compare brain tissue in patients with Alzheimer disease with that in elderly control subjects by using high-resolution MR imaging and quantitative tissue-segmentation techniques.METHODSMR imaging of the brain was performed in 21 patients with Alzheimer disease and 17 control subjects. A computerized segmentation program was used to quantify volumes of ventricular and sulcal cerebrospinal fluid (CSF), white matter, cortical gray matter, and white matter signal hyperintensity. Statistical analysis was performed using analysis of variance.RESULTSWe found a significant decrease in total brain tissue and cortical gray matter and an increase in the ventricular and sulcal CSF in Alzheimer patients compared with control subjects. There was no difference in the volume of white matter. More white matter signal hyperintensities were found in Alzheimer patients, and a significant interaction between age and group was noted. Neuropsychological test scores correlated significantly with sulcal CSF in patients with Alzheimer disease.CONCLUSIONSemiautomated segmentation of MR images of the brains of patients with Alzheimer disease reveals significant brain atrophy attributable to loss of cortical gray matter, which is compatible with the pathologic features of Alzheimer disease. There is also a significant increase in white matter signal hyperintensities. Tissue segmentation may increase our understanding of dementia but, as yet, when used alone, it does not play a role in the premorbid diagnosis of Alzheimer disease.     

Unsupervised,automated segmentation of the normal brain using a multispectral relaxometric magnetic resonance approach

The purpose of this study was the development and testing of a method for unsupervised, automated brain segmentation. Two spin-echo sequences were used to obtain relaxation rates and proton-density maps from 1.5 T MR studies, with two axial data sets including the entire brain. Fifty normal subjects (age range, 16 to 76 years) were studied. A Three-dimensional (3D) spectrum of the tissue voxels was used for automatic segmentation of gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) and for calculation of their volumes. Accuracy and reproducibility were tested with a three-compartment phantom simulating GM, WM, and CSF. In the normal subjects, a significant decrease of GM fractional volume and increased CSF volume with age were observed (P < 0.0001), with no significant changes in WM. This multi-spectral segmentation method permits reproducible, operator-independent volumetric measurements.     

Gray matter N-acetyl aspartate deficits in secondary progressive but not relapsing-remitting multiple sclerosis

BACKGROUND AND PURPOSE: Spectroscopic examination of multiple sclerosis (MS) patients has revealed abnormally low N-acetyl-aspartate (NAA) signal intensity, even in brain tissue that appears normal on high-resolution structural MR images but has yielded inconclusive evidence to distinguish the well-documented clinical differences between MS subtypes. This study used proton MR spectroscopic imaging (MRSI) and high-resolution MR imaging to characterize metabolite profiles in normal-appearing brain tissue of relapsing-remitting multiple sclerosis (RRMS) and secondary progressive (SP) MS. METHODS: Volumetric spiral MRSI was used together with high-resolution MR imaging to derive absolute measures of metabolite concentrations separately in normal-appearing supratentorial cerebral gray matter and white matter in five RRMS patients, five SPMS patients, and nine age-matched controls. Structural MR images were segmented into compartments of gray matter, white matter, CSF, and lesions, and metabolite signals per unit of tissue volume were calculated for gray matter and white matter separately. RESULTS: Only the SPMS group had significantly lower NAA concentrations in normal-appearing gray matter compared with concentrations in controls. NAA in normal-appearing white matter was equally reduced in RRMS and SPMS patients. The functional relevance of this brain metabolite measure was suggested by the observed but statistically nonsignificant correlation between higher disability scores on the Expanded Disability Status Scale and lower gray matter NAA concentrations. CONCLUSION: The otherwise occult abnormality in supratentorial gray matter in SPMS but not RRMS may explain the more severe physical and cognitive impairments afflicting patients with SPMS that do not correlate well with visible lesion burden.     

Contrast-driven approach to intracranial segmentation using a combination of T2- and T1-weighted 3D MRI data sets

PURPOSE: To develop a strategy for structural brain imaging when using FSL software for segmentation and subsequent volumetry. MATERIALS AND METHODS: Three-dimensional (3D) structural MRI of 1-mm isotropic resolution was performed on a 3-Tesla clinical imaging system. Prescribed signal evolution of a multiple spin-echo (SE) sequence with variable refocusing flip angle for T2 weighting, and a modified driven equilibrium Fourier transform (MDEFT) sequence were used for T1 weighting. Postprocessing included rigid-body coregistration, brain extraction, and segmentation using the tools of the FSL 3.2 software package. RESULTS: T2 weighting provided reliable delineation of the subarachnoidal space, while T1 weighting provided better segmentation of gray matter (GM) and white matter (WM). The combination of T1-weighted (T1-w) and T2-w data allowed the identification of a T2-hypointense class of "nonbrain" (NB) representing larger vessels and structures of connective tissue, as well as partial volume of bone and air-filled cavities. CONCLUSION: Brain extraction on T2-w data and subsequent segmentation of the combined T1- and T2-w intensity distribution into four classes are recommended.     

脑结节性硬化的MR DWI分析

目的:使用磁共振扩散加权成像(DWI)研究结节性硬化(TS)患者脑灰质和白质内病灶的扩散特点,并观察表观扩散系数(ADC)的变化。方法:对18例临床影像学诊断的TS患儿使用1.5TMR系统行DWI检查,测量大脑皮质和皮质下61个结节的ADC值和对照组15例正常儿童的正常白质的ADC值。结果:TS患儿大脑皮质和白质病灶的ADC值明显高于健康儿童正常脑白质的ADC值,两者存在统计学差异(P<0.001)。其中4例TS伴发的室管膜下巨细胞星形细胞瘤ADC值与正常脑实质的相似,两者无统计学差异(P>0.05)。结论:DWI可提供TS患儿脑皮质和白质病灶的病理信息,TS脑白质内结节灶的高ADC值可区别常规MRI检查T1WI和T2WI信号与TS相似的其他疾病结节状病灶。     

FLAIR序列对脑梗塞的诊断价值

目的：探讨长回波时间的液体抑制反转恢复脉冲序列（ＦＬＡＩＲ）对脑梗塞的诊断及鉴别诊断价值。材料和方法：对２１例经常规ＭＲＩ诊断为脑梗塞的患者进行ＦＬＡＩＲ序列成像，并与ＳＥ序列Ｔ２加权像比较。结果：在２１例脑梗塞病例中，ＦＬＡＩＲ显示病变较Ｔ２加权像清楚明确的１７例（占８１．０％）。Ｔ２加权像难以发现病灶的（＞１个）１５例占７１．４％。结论：ＦＬＡＩＲ序列对脑梗塞病变的显示具有更高的敏感性。特别适合于发现大脑半球表面、基底池周围、灰白质交界及脑室旁区的微小病变。且对梗塞病灶的分期、脑表面梗塞灶与蛛网膜下腔扩大，囊肿的鉴别有帮助。     

Early assessment of brain maturation by MR imaging segmentation in neonates and premature infants

PURPOSE: We evaluated the impact of premature extrauterine life on brain maturation. PATIENTS AND METHODS: Twelve neonates underwent MR imaging at 40 (39.64 +/- 0.98) weeks (full term). Fifteen premature infants underwent 2 MR imaging examinations, after birth (preterm at birth) and at 40 weeks (41.03 +/- 1.33) (preterm at term). A 3D MR imaging technique was used to measure brain volumes compared with intracranial volume: total brain volume, cortical gray matter, myelinated white matter, unmyelinated white matter, basal ganglia (BG), and CSF. RESULTS: The average absolute volume of intracranial volume (269.8 mL +/- 36.5), total brain volume (246.5 +/- 32.3), cortical gray matter (85.53 mL +/- 22.23), unmyelinated white matter (142.4 mL +/-14.98), and myelinated white matter (6.099 mL +/-1.82) for preterm at birth was significantly lower compared with that for the preterm at term: the average global volume of intracranial volume (431.7 +/- 69.98), total brain volume (391 +/- 66,1), cortical gray matter (179 mL +/- 41.54), unmyelinated white matter (185.3 mL +/- 30.8), and myelinated white matter (10.66 mL +/- 3.05). It was also lower compared with that of full-term infants: intracranial volume (427.4 mL +/- 53.84), total brain volume (394 +/- 49.22), cortical gray matter (181.4 +/- 29.27), unmyelinated white matter (183.4 +/- 27.37), and myelinated white matter (10.72 +/- 4.63). The relative volume of cortical gray matter (30.62 +/- 5.13) and of unmyelinated white matter (53.15 +/- 4.8) for preterm at birth was significantly different compared with the relative volume of cortical gray matter (41.05 +/- 5.44) and of unmyelinated white matter (43.22 +/- 5.11) for the preterm at term. Premature infants had similar brain tissue volumes at 40 weeks to full-term infants. CONCLUSION: MR segmentation techniques demonstrate that cortical neonatal maturation in moderately premature infants at term and term-born infants was similar.     

Interactive segmentation of cerebral gray matter, white matter, and CSF: Photographic and MR images

Digital photography of postmortem brain slices was compared with magnetic resonance imaging (MRI) for morphological analysis of human brain atrophy. In this study, we used two human brains obtained at autopsy: a cognitively defined nondemented control (70-yr-old male) and a demented Alzheimer's disease (AD) subject (82yr-old female). For each of two brains, interactive manual image segmentation was performed by two observers on two image sets: (a) four coronal T1-weighted MR images (5 mm slices); and (b) four digitized photographic images from comparable rostrocaudal levels. Microcomputer image analysis software was used to measure the areas of three segmented cerebral compartments—gray matter (GM), white matter (WM) and CSF—for both image types. Resegmentation error was defined as the absolute difference between the areas derived from two segmentation trials divided by the value from trial 1 and multiplied by 100. This yielded the percent difference between the area measurements from the two trials. We found intea-observer agreement was better (error rates 1–18%) than inter-observer agreement (3–70%) with best agreement for WM and least for CSF, the smallest object class. MRI overestimated GM area relative to digitized photographs in the control but not the AD brain. The results define limitations of manual image segmentations and comparison of MRI with pathologic section photographic images.     

MR imaging assessment of brain and cervical cord damage in patients with neuroborreliosis

BACKGROUND AND PURPOSE: Neuroborreliosis is frequently indistinguishable from multiple sclerosis (MS) on both clinical and radiologic grounds. By using MR imaging, we assessed "occult" brain white matter (WM), brain gray matter (GM), and cervical cord damage in patients with neuroborreliosis in an attempt to achieve a more accurate picture of tissue damage in these patients, which might contribute to the diagnostic work-up. METHODS: We studied 20 patients with neuroborreliosis and 11 sex- and age-matched control subjects. In all subjects, we acquired dual echo, T1-weighted, diffusion tensor (DT) and magnetization transfer (MT) MR imaging scans of the brain and fast short-tau inversion recovery and MT MR imaging scans of the cervical cord. T2-visible lesion load was measured by using a local thresholding segmentation technique. Mean diffusivity and fractional anisotropy histograms of the brain and cervical cord MT ratio histograms were produced. Normalized brain volumes (NBV) were measured by using SIENAx. RESULTS: Brain T2-visible lesions were detected in 12 patients, whereas no occult damage in the normal-appearing WM and GM was disclosed by using MT and DT MR imaging. No macroscopic lesions were found in the cervical cord, which was also spared by occult pathology. NBV did not differ between patients with neuroborreliosis and control subjects. CONCLUSION: This study shows that, contrary to what happens in MS, occult brain tissue damage and cervical cord pathology are not frequent findings in patients with neuroborreliosis. These observations might be useful in the diagnostic work-up of patients with neuroborreliosis and T2 brain lesions undistinguishable from those of MS.     

Human brain atlas‐based volumetry and relaxometry: Application to healthy development and natural aging

This work investigated the feasibility and utility of using T2‐weighted or dual spin‐echo data to provide volume and T2 relaxation time for regional and global gray and white matter using standardized brain templates and anatomically labeled atlases. A total of 130 healthy males and females (age range 15–59 years) were included. Dual echo magnetic resonance imaging data were acquired and analyzed using standardized International Consortium for Human Brain Mapping atlas‐based tissue segmentation procedures implemented in the statistical parametric mapping toolbox to obtain the age trajectories of volume and corresponding T2 relaxation time in whole brain white and gray matter, in the caudate nucleus and in the anterior limb of internal capsule. Whole brain gray matter and caudate nucleus volumes linearly decreased with age while whole brain white matter and anterior limb internal capsule volume increased slowly with age bilaterally in males and females. The relation between T2 relaxation time and age of whole brain gray and white matter, and caudate nucleus and anterior limb internal capsule followed a quadratic U‐curve. The T2 relaxation times of the human brain followed a U curve both globally and regionally in both white and gray matter. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.