定量磁化率成像及其在脑铁定量中的研究进展

定量磁化率成像(quantitative susceptibility mapping,QSM)是从SWI基础上发展起来的一项新技术,它通过从场到源的反演计算得出组织磁化率值,可精确地反映组织本身固有的磁化率,其与铁含量呈正相关性。本文将QSM与传统铁定量的T2、T2*弛豫法及基于磁化率差异成像的SWI进行了比较,并介绍了QSM在脑铁定量方面的研究进展。     

基于multi-atlas QSM定量分析阿尔茨海默病脑基底核团异常铁沉积

【摘要】目的：基于多图谱（multi-atlas）的磁化率成像（QSM）定量分析，评估阿尔茨海默病（AD）患者大脑基底核团的异常铁沉积，并探讨其与认知功能改变的关系。方法：搜集在本院神经内科门诊就诊的符合NINCDS-ADRDA标准的34例AD患者的病例资料，男14例、女20例，年龄（67.9±7.7）岁。同期自社区招募年龄、性别和教育程度相匹配的34例健康志愿者（正常对照组），其中男12例、女22例，年龄（65.4±5.8）岁。所有被试行高分辨率三维容积T1WI和多回波梯度回波序列MRI扫描。对多回波梯度回波序列进行图像重建得到QSM图像，然后利用MRICloud平台，进行基于QSM和T1WI双通道（双对比度）的多图谱分析，自动分割脑基底核团并测量其磁化率值，比较两组间磁化率的差异，同时分析AD患者基底核团磁化率与简易精神状态量表（MMSE）评分的关系。结果：与正常对照组比较，AD患者双侧尾状核、右侧外侧苍白球、双侧壳核、双侧背侧丘脑、双侧丘脑底核及双侧红核的磁化率升高（P均<0.05，未校正）；经多重比较矫正后，仅右侧壳核（P=0.002）和左侧背侧丘脑（P=0.001）的磁化率与对照组之间的差异有统计学（P<0.05，Bonferroni校正）。皮尔森相关分析显示，右侧壳核（r=－0.302，P=0.020）和左侧背侧丘脑（r=－0.319，P=0.014）的磁化率与MMSE评分呈显著负相关。结论：AD患者大脑深部基底核团的铁含量较健康人群显著增加，且与患者认知功能的下降具有相关性；基于multi-atlas的QSM定量分析方法可用于AD患者基底核团异常铁沉积的定量评估。     

定量磁敏图基本原理及其在中枢神经系统应用进展

【摘要】定量磁敏感图（quantitativesusceptibilitymapping,QSM）是利用梯度回波相位图检测体内分布的磁敏感物质、并计算其磁化率值的一种成像技术,在脑内铁含量、血液中脱氧血红蛋白量的测量中具有较高的临床应用价值,本文将介绍QSM的基本原理及其在中枢神经系统的应用进展。     

QSM对无轻度认知功能障碍的2型糖尿病病人脑内铁沉积的评估

目的 探讨不伴有轻度认知功能障碍(MCI)的2型糖尿病(T2DM)病人脑内铁含量改变,及其与认知功能改变的相关性。方法 前瞻性纳入不伴MCI的T2DM病人27例(T2DM组)及健康对照30例(HC组),2组性别、年龄相匹配,均进行认知功能和情绪状态评估并完成定量磁化率成像(QSM)。在QSM图上手动勾画兴趣区(ROI),包括双侧尾状核、壳核、苍白球、丘脑、红核、黑质、小脑齿状核,测定每个ROI内磁化率值。采用独立样本t检验、卡方检验比较2组的临床资料和ROI内磁化率值,采用配对t检验比较2组内同一脑区双侧ROI的磁化率值。以年龄、性别、教育年限作为协变量,在T2DM组中对2组间存在差异的量表评分和磁化率值进行偏相关分析。结果 与HC组相比,T2DM组蒙特利尔认知评估(MoCA)量表评分中的命名能力评分及右侧丘脑磁化率值较低,MoCA量表抽象能力评分较高(均P<0.05)。双侧脑区磁化率比较显示,T2DM组的左侧齿状核磁化率值高于右侧,HC组的右侧黑质磁化率值高于左侧(均P<0.05)。T2DM组的右侧丘脑磁化率值与MoCA量表内抽象能力评分呈负相关(r=-0.548,P=0...     

铁沉积定量测量在认知功能障碍中的研究进展

认知功能障碍继发于多种疾病,但各类病因造成的认知功能障碍者普遍存在脑内的异常铁沉积,其可能参与该类病人认知功能损害的病理过程。定量磁化率图（QSM）是一种新兴的定量检测组织磁化特性的MRI技术,可以定量分析脑内的异常铁沉积,有助于进一步探索认知功能障碍的发病机制。综述QSM的铁沉积定量测量在阿尔茨海默病（AD）、血管性痴呆（VaD）、帕金森病（PD）、2型糖尿病（T2DM）及一些其他疾病引发的认知功能损害的研究进展。     

定量磁敏感图在神经系统中的研究进展

定量磁敏感图(QSM)是一种基于MR相位检测体内的磁敏感物质并准确计算其磁化率值的成像技术,相较于传统的磁敏感加权成像,因其后处理方法不同而具有更精确的磁化率定量及更高的组织间对比度。近年来,QSM在中枢神经系统的研究中快速发展,就QSM在神经系统退行性疾病脑内深部核团铁质沉积、脑白质病变机制探讨、钙化与出血性病变的鉴别以及脑内细微结构的显示等方面的研究进展进行综述,以提高对QSM的认识并进一步拓宽其研究范围。     

定量磁敏感加权图联合水脂分离技术在肝脏铁及脂肪定量中的可行性研究

【摘要】目的：探讨定量磁敏感图（QSM）联合水脂分离技术计算肝脏铁含量和脂肪含量,并与FerriScan铁定量和波谱（MRS）脂肪定量进行对比。方法：纳入20例正常志愿者及26例铁沉积患者,分别进行ME-FGRE、QSM及MRS成像。在AW工作站中进行后处理,计算ME-FGRE的R2*值、QSM磁敏感值和脂肪分数,同时测量MRS脂肪分数。采用Pearson相关分析正常志愿者及铁沉积患者R2*值、磁敏感值和铁含量之间相关性。采用独立样本t检验对比QSM和MRS得到的脂肪分数。结果：正常志愿者和铁沉积患者脏的磁化率值和脂肪分数值分别为(0.13±0.03)ppm、（3.92±0.84）%和(2.15±0.63)ppm和（6.39±3.73）%,ME-FGRE得到的R2*值分别为(48.8±4.4)Hz和(212.8±95.0)Hz,MRS脂肪分数分别为（3.95±0.72）%和（6.11±3.42）%。正常志愿者和铁沉积患者磁化率值和LIC的相关值分别为0.964和0.924。正常志愿者和铁沉积患者两种方法得到的脂肪分数均无差异。结论：QSM联合水脂分离成像在肝脏铁和脂肪定量中有潜在价值。     

定量磁化率图对脑微出血铁含量动态变化的随访研究

目的 应用定量磁化率图（QSM）随访研究脑内微出血（CMB）病灶体积变化与磁敏感值变化之间的相关性,探讨CMB铁含量的动态变化。 方法 回顾性收集行头颅常规MRI序列及磁敏感加权成像（SWI）序列检查中具有明确CMB的病人资料,所有病人均进行了基线和随访检查（2次检查时间间隔约12个月）。共纳入病人35例,男27例,女8例,平均（67.94±9.57）岁。将SWI序列原始相位图和幅度图进行后处理得到QSM,在基线和随访QSM上手动勾画CMB的兴趣区（ROI）,选取ROI内磁敏感值≥130ppb的CMB病灶,测量ROI内像素数作为CMB体积;同时在ROI上测量并记录CMB最大磁敏感值、平均磁敏感值。根据随访与基线CMB体积变化,将CMB病灶分为体积增大、体积减小及体积不变组。采用Spearman相关分析CMB体积与最大磁敏感值、平均磁敏感值的相关性。采用配对样本t检验比较不同组内基线及随访CMB的磁敏感值变化。 结果 共纳入CMB 病灶322个,其基线QSM上所示病灶体积、最大磁敏感值、平均磁敏感值均高于随访QSM所见（均P<0.05）。基线及随访的CMB体积与最大磁敏感值、平均磁敏感值均呈正相关（均P<0.05）。根据随访与基线CMB体积变化,将病灶分为增大组108个、减小组198个、不变组16个。体积增大组随访水平的最大磁敏感值、平均磁敏感值均高于基线水平（均P<0.05）;体积减小组随访水平最大磁敏感值、平均磁敏感值均低于基线水平（均P<0.05）;体积不变组随访水平和基线水平的差异无统计学意义（均P>0.05）。 结论 随着时间的推移,CMB病灶体积、磁敏感值会发生变化。CMB磁敏感值的变化受体积变化的影响,间接反映CMB铁含量的动态变化。     

基于定量磁敏感成像的重性抑郁障碍与双相情感障碍脑区测量分析

【摘要】目的：基于定量磁敏感成像（QSM）技术分析重性抑郁障碍（MDD）与双相情感障碍（BD）患者基底节与边缘系统脑区铁沉积情况及其与抑郁症状严重程度的关系。方法：搜集MDD、BD患者与健康对照（HC）组各20例,使用汉密尔顿抑郁量表（HAMD）评估患者抑郁严重程度,采集受试者全脑QSM图像。测量尾状核、苍白球外侧部、苍白球内侧部、壳核、黑质、丘脑底核、直回、眶部内侧回、眶部后回、梭状回、海马旁回、颞上回、颞中回、颞下回的感兴趣区（ROI）内平均磁化率值,并计算各脑区偏侧化指数（LI）。采用多独立样本Kruskal-Wallis检验进行组间比较,Spearman相关性分析磁化率值与HAMD评分的相关性。结果：组间比较结果显示,MDD组左侧海马旁回磁化率值低于BD组（P=0.047）;MDD组眶部内侧回LI高于BD组（P=0.005）。相关性分析结果显示,MDD组右侧尾状核磁化率值与HAMD评分呈正相关（r=0.569,P=0.009）,BD组右侧颞中回磁化率值与HAMD评分呈正相关（r=0.545,P=0.013）。结论：MDD、BD患者间存在铁沉积区域性与偏侧性差异,特定脑区铁沉积水平与抑郁症状严重程度相关。     

定量磁敏感图成像对早期高血压的初步研究

目的利用磁共振定量磁敏感图成像(quantitative susceptibility mapping, QSM)技术,检测早期高血压患者脑部核团的铁沉积含量,探究高血压病的病理生理变化机制。方法观察对象包括23例早期高血压患者,对照组20例,两组年龄性别相匹配。43例受试者均行3.0T磁共振定量磁敏感(QSM)技术检查,测量受试者双侧苍白球、壳核、尾状核头、黑质、红核、丘脑的磁化率值(即相对铁含量)。采用t检验对两组之间和大脑左右双侧磁化率值做统计学比较。结果高血压组双侧红核相对铁含量[左=(0.1213±0.0278)ppm、右=(0.1343±0.0992)ppm]和对照组[左=(0.1043±0.02520)ppm、右=(0.1009±0.02660)ppm]有统计学显著差异(左P=0.001、右P=0.024)。其它核团包括苍白球、壳核、尾状核、黑质、丘脑等相对铁含量两组之间无统计学差异,大脑双侧核团相对铁含量用配对t检验分析未见统计学差异。结论通过磁共振QSM技术,检测到早期高血压患者脑部核团红核的铁沉积含量有升高改变,进一步加深对高血压病的病理变化过程的认识,并为将来的临床诊断与治疗提供客观依据。     

白藜芦醇对大鼠创伤性脑水肿的影响及超微结构观察

目的：探讨白藜芦醇对自由落体伤大鼠脑水肿的影响及超微结构变化。方法：采用自由落体伤获得大鼠脑创伤模型，白藜芦醇腹腔注射治疗，取创伤区脑组织，烤箱内干燥，根据烘烤前后质量差，得出脑含水量，用统计方法分析数据；另取部分伤区脑组织行电子显微镜观察。结果：白藜芦醇治疗后大鼠脑含水量差异性明显，超微结构亦有不同改变。结论：白藜芦醇能减轻创伤后大鼠脑水肿，同时对伤区脑组织超微结构有保护作用。     

Radiological study of the brain at various stages of human immunodeficiency virus infection: early development of brain atrophy

Summary One hundred and one persons infected with human immunodeficiency virus (HIV-1), in whom other central nervous system infections or diseases were excluded, underwent brain CT and/or MRI at various stages of HIV-1 infection: 29 were asymptomatic (ASX), 35 had lymphadenopathy syndrome (LAS), 17 had AIDS-related complex (ARC), and 20 had AIDS. A control group of 32 HIV-1-seronegative healthy persons underwent brain MRI. The most common finding was brain atrophy, found in 9% of controls, and 31% of ASX cases, 29% of LAS, 59% of ARC and 70% of AIDS. Even the difference between the ASX or LAS groups and controls was significant. The changes were bilateral and symmetrical, and they were more severe at later stages of infection. Infratentorial atrophy was seen in the early stages; supratentorial atrophy became more pronounced at ARC, and generalized atrophy was typical of AIDS. Non-specific small hyperintense foci were found on MRI in 13% of controls and 6–15% of the infected groups. Larger, diffuse, bilateral white matter infiltrates were detected in 4 demented patients with AIDS. Four patients with AIDS and 1 with LAS had focal hyperintense lesions in the internal capsules, lentiform nuclei or thalamus, often bilateral on MRI. One patient with AIDS, examined with CT only, had low density in the lentiform nucleus. Loss of brain parenchyma can occur at an early stage of HIV-1 infection, and the atrophic process becomes more intense at later stages (ARC and AIDS). Parenchymal infiltration, seen as hyperintense areas on MRI, is most often associated with severe clinical symptoms, in the later stages of the disease.     

弥漫性脑损伤后脑缺血的实验研究

目的　运用大鼠弥漫性脑损伤 (DBI)模型研究脑外伤后脑缺血缺氧的形态学改变。　方法　采用Marmarou的DBI模型 ,光镜下观察微血管改变并测量顶叶皮质内微血管的截面积及微血管周的水肿面积 ;电镜下观察血脑屏障结构的形态学改变并半定量测定毛细血管周围的水肿范围。　结果　光镜下可见外伤后 2 ,6 ,2 4h微血管管径变窄 ,平均微血管截面积分别为 (41.77± 2 7.37) μm2 、(45 .0 9± 2 4 .75 ) μm2 、(49.38± 2 5 .13) μm2 ,均小于对照组 [(6 2 .0 7± 2 8.4 5 ) μm2 ](P <0 .0 5 )。伤后 6 ,2 4h微血管周围存在明显水肿。电镜下 2 ,6 ,2 4h血脑屏障结构有明显损害 ;微血管有痉挛、受压变窄及淤血三种改变。　结论　弥漫性脑损伤后存在明显的脑缺血缺氧的病理形态学改变。     

Quantitative analysis of brain asymmetry by using the divergence measure: normal-pathological brain discrimination

RATIONALE AND OBJECTIVES: The human brain demonstrates approximate bilateral symmetry of anatomy, function, neurochemical activity, and electrophysiology. This symmetry reflected in radiological images may be affected by pathology. Hence quantitative analysis of brain symmetry may enable the normal and pathological brain discrimination. We propose a method based on the Jeffreys divergence measure (J-divergence), which attempts to quantify "approximate symmetry" and also aids to classify the brain as bilaterally symmetrical/asymmetrical (normal/abnormal). MATERIALS AND METHODS: The dataset included studies of 101 patients (59 without detectable pathologies and 42 with different abnormalities). First, the midsagittal plane is computed for the volume data that divides the head into two hemispheres. The J-divergence is calculated from the density functions of intensities of both the hemispheres. Statistical analysis was conducted to find the best distribution for normal/abnormal datasets. RESULTS: Statistical tests showed that the lognormal distribution best characterizes the values of the J-divergence for both normal and abnormal cases, and the threshold value for the Jeffreys divergence measure to classify the brains with and without detectable pathologies is T = 0.007. The threshold value had a sensitivity of 88.1% and specificity of 90.9%. CONCLUSION: The proposed method is fast and simple to compute. The high sensitivity and specificity indicate the results are encouraging. This method can be used for the initial analysis of data, detection of pathology, classification of dataset as presumably normal/abnormal, and localization of abnormality.     

颅脑MRI快速液体衰减反转回复技术探讨

目的：探讨快速液体衰减反转回复（ＦＬＡＩＲ）技术原理及其在颅脑的临床应用。材料与方法：对４０例健康志愿者及１２４例颅脑疾患患者前瞻性地进行快速ＦＬＡＩＲ及Ｔ２加权序列ＭＲ检查，并比较了快速ＦＬＡＩＲ上不同ＴＲ、ＴＩ（间隔时间）、ＴＥ组合所得图像质量。结果：ＴＲ／ＴＩ／ＴＥ为８０００／２０００／２００毫秒的组合能较好地抑制脑脊液信号。ＦＬＡＩＲ与快速自旋回波Ｔ２加权序列比较，能增加病灶的对比度，从而     

NMR imaging of the brain

Summary The basic features of an NMR imaging system are outlined and three pulse sequences which produce images with varying dependence on proton density T₁ and T₂ are described. The first of these sequences, Repeated Free Induction Decay produces images which demonstrate changes in proton density as well as flow effects. The second sequence, Inversion-recovery, produces images which are dependent on T₁ and show a high level of grey, white matter contrast giving considerable anatomical detail. In addition pathological processes such as infarction, haemorrhage, demyelination and malignancy produce changes in T₁ enabling lesions to be localised. The third sequence, Spin-echo, produces images which are dependent on T₂. These show very little grey, white matter contrast but demonstrate acute and space occupying lesions as well as cerebral oedema. The high level of grey, white matter contrast, lack of bone artefact, variety of sequences, capacity for multiplanar imaging, sensitivity to pathological change and lack of known hazard make NMR an important addition to existing techniques of neurological diagnosis.     

Localized proton MR spectroscopy of the brain in children

Small-voxel (3.0–8.0 cm³), magnetic resonance (MR) imaging–guided proton MR spectroscopy was performed in 54 patients (aged 6 days to 19 years) with intracranial masses (n = 16), neurodegenerative disorders (n = 34), and other neurologic diseases (n = 4) and in 23 age-matched control subjects without brain disease. A combined short TE (18 msec) stimulatedecho acquisition mode (STEAM) and long TE (135 and/or 270 msec) spin-echo point-resolved spatially localized spectroscopy (PRESS) protocol, using designed radio-frequency pulses, was performed at 1.5 T. STEAM spectra revealed short T2 and/or strongly coupled metabolites; prominent resonances were obtained from N-acetyl aspartate (NAA), choline-containing compounds (Cho), and total creatine (tCr). Lactate was well resolved with the long TE PRESS sequence. Intracranial tumors were readily differentiated from cerebrospinal fluid (CSF) collections. All tumors showed low NAA, high Cho, and reduced tCr levels. Neurodegenerative disorders showed low or absent NAA levels and enhanced mobile lipid, glutamate and glutamine, and inositol levels, consistent with neuronal loss, gliosis, demyelination, and amino acid neuro-toxicity. Preliminary experience indicates that proton MR spectroscopy can contribute in the evaluation of central nervous system abnormalities of infants and children.     

Neuropathology and brain weight in traumatic-crush asphyxia

Traumatic (crush) asphyxia is a rare condition caused by severe compression of the chest and trunk leading to often extreme so-called asphyxial signs, including cyanosis in head and neck regions, multiple petechiae, and subconjunctival haemorrhage as well as neurological manifestations.AimsTo investigate the neuropathology and brain weight in traumatic asphyxia caused by different accidents such as industrial accidents and road traffic collision.Material and MethodsPost mortem records of 20 cases of traumatic asphyxia (TA) resulting from different causes of which four brains are available for comprehensive neuropathological examination. The expected brain weights for given body height and associated 95% confidence range were calculated according to the following formula: baseline brain weight (BBW) + body height x rate (g/cm). The 95% confidence range was calculated by adding and subtracting the standard error (SE) x 1.96 (7–8).ResultsThere was a trend for higher brain weight in the TA cohort but it was not significant (1494 g vs 1404 g, p = 0.1). The upper limits of the brain weight of 95% confidence was 1680 g vs 1660 g, p = 0.9.The neuropathological examination of four available brains from the TA cohort showed severe congestion of blood vessels, perivascular haemorrhages and occasional βAPP deposits consistent with early axonal disruption.ConclusionBrain examination is informative as part of investigation of TA. Developing ischaemic changes and an increase in brain weight are the most likely indicators of a prolonged period of patient's survival.     

Whistling face syndrome: MR imaging findings in the brain

Whistling face syndrome or cranio-carpotarsal dysplasia is a very rare disorder that consists of a characteristics facies and digital abnormalities. Magnetic resonance imaging investigation of the brain in this syndrome has not been reported previously. This communication describes the brain malformations in an infant with the syndrome, which covered delayed myelination, thickened and infolded cortices (cortical dysplasia), dysplastic corpus callosum, and agenesis of the inferior vermis.