The use of magnetic resonance imaging for the diagnosis of fetal intracranial anomalies

While fetal cranial sonography has been used for the sensitive detection of ventriculomegaly, ancillary imaging techniques may be needed for precise delineation of structural abnormalities. This report outlines the radiologic and clinical results using maternal magnetic resonance imaging (MRI) in ten patients with suspected fetal intracranial anomalies. Imaging was accomplished at 17–39 weeks gestational age, using spin-echo, a multislice technique with intramuscular morphine sulfate for sedation. In four cases, MRI significantly clarified the sonographic diagnosis, while in two cases the scan agreed with the sonographic findings. In one patient, MRI failed to image a lumbar meningomyelocele associated with the Chiari II malformation. In two patients with the Chiari II malformation, both sonography and MRI failed to delineate the anatomic pathology completely. Optimal imaging resolution was achieved in the third trimester. Four patients died in the perinatal period. All the surviving patients required shunting to treat intracranial hypertension; only two patients were meeting cognitive milestones. We conclude that due to the high incidence of multiple anomalies in the fetus with ventriculomegaly, precision in neuroradiological diagnosis is essential. MRI can be a useful adjunct to cranial sonography for the specific delineation of abnormalities of the fetal central nervous system.     

脑桥出血早期患者脑皮质结构变化的磁共振研究

目的探讨脑桥出血早期患者脑皮质结构变化,并分析与感觉运动功能损伤的相关性。方法选择2014年5月至2015年3月本院接诊的16例脑桥出血患者进行研究将其作为观察组,选取同期16例健康者作为对照组。观察组患者入院后给予结构磁共振(MRI)检测,通过基于体素形态学方法对MRI的结构数据进行分析,比较两组患者大脑灰质体积区域的改变。并通过相关性分析患者脑皮质结构的改变与运动感觉功能的关系。结果两组患者在年龄与性别方面差异无统计学意义(P0.05);观察组的轻触觉评分、针刺觉评分以及运动评分均低于对照组,两组比较差异具有统计学意义(P0.001);基于体素形态学方法分析结果显示,观察组的双侧初级感觉中心、初级运动中心及其辅助运动区发生了灰质体积减小的现象(P0.05);观察组结构异常区域萎缩发生程度经相关分析与轻触觉评分、针刺觉评分以及运动评分无相关性(P0.05)。结论脑桥出血早期患者初级感觉中心、初级运动中心及其辅助运动区发生了灰质萎缩,但是萎缩程度与患者轻触觉评分、针刺觉评分以及运动评分无关。     

遗忘型轻度认知功能损害患者大脑皮质结构磁共振成像的改变

目的 运用MRI及FMRIB software library(FSL)和Freesurfer软件包分析技术,研究遗忘型轻度认知功能损害(amnestic mild cognitive impairment,aMCI)患者全脑皮质结构改变情况.方法 对20例aMCI患者和20名年龄、性别、文化程度相匹配的健康志愿者,应用SEMENTS trio3.0 T MRI仪,采用高分辨扫描技术获取大脑精细结构立体像,然后应用FSL软件和Freesurfer软件包进行数据分析和后处理,计算出全脑不同部位皮质密度和厚度,比较aMCI组与健康对照组皮质结构特征的区别.结果 与健康对照组相比,aMCI组的左侧额叶、顶叶、颞叶皮质密度显著降低,右侧丘脑、颞叶及左侧岛叶皮质密度轻度降低;aMCI组左侧前扣带回[(2.19±0.24)mm]、顶下小叶[(2.27±0.15)mm],双侧海马旁回[(2.03±0.15)、(2.04±0.17)mm]、额上回[(2.42±0.34)、(2.40±0.28)mm]、额中回[(2.31±0.31)、(2.33±0.29)mm]、颞极[(3.41±0.68)、(3.30±0.56)mm]、颞横回[(2.04±0.12)、(2.01±0.11)mm]、中央前回[(2.20±0.11)、(2.31±0.19)mm]、中央后回[(1.88±0.11)、(1.82±0.09)mm]、缘上回[(2.53±0.33)、(2.55±0.23)mm]的皮质厚度显著降低(t=2.13～3.75,P＜0.05),其余部位无明显改变(t=0.09～1.88,P＞0.05).结论 aMCI患者大脑多个部位存在皮质结构改变,皮质厚度的变薄早于密度的降低.     

The role of diffusion-weighted magnetic resonance imaging in pediatric brain tumors

Objectives Diffusion-weighted imaging (DWI) may enhance the radiographic diagnosis of pediatric brain tumors. This study reviews the DWI properties of pediatric brain tumors at our institution and examines their relationship to tumor grade and type.Materials and methods The preoperative DWI and apparent diffusion coefficient (ADC) characteristics of brain tumors in 41 children were compared with histologic diagnosis. Signal characteristics on DWI and ADC maps correlated well with tumor grade. High-grade lesions were hyperintense on DWI and hypointense on ADC maps. Sensitivity, specificity, positive predictive value, and negative predictive value were 70, 100, 100, and 91%, respectively. Signal characteristics did not differ among different tumors of the same grade. All primitive neuroectodermal tumors showed diffusion restriction whereas none of the ependymomas did.Conclusions The signal characteristics on DWI and ADC maps appeared to be strongly correlated to grade in pediatric brain tumors and they may assist with preoperative diagnostic predictions.     

多发性硬化患者的脑部磁共振成像表现

目的　寻找多发性硬化(multiplesclerosis,MS)患者有诊断及鉴别诊断意义的脑部磁共振成像(MRI)征象。方法　分析41例临床确诊MS患者的常规脑部MRI表现,内容包括病灶数目、分布、大小、形态、信号特征及增强表现等。结果　脑部的MS灶可以单发和多发,单发者幕下多见,多发者以4~15个病灶者最多。少数病例的病灶弥漫分布,无法计数,呈现“白质变脏征”。斑块分布以两侧脑室旁最多见,其次为额顶叶皮层下、胼胝体、脑干,伴发小脑内病灶仅2例。斑块直径约几个毫米至2cm不等,约占75%; 2cm以上病灶者少见,最大病灶约6~7cm。根据形态和信号,病灶可以分为急性和慢性。急性病灶呈卵圆形或圆形,有明显膨胀感,T1WI呈低或略低信号,周围可见等或略高信号;T2WI呈高信号,但增高程度不同,表现为中央呈“核心”而周围呈“晕环”。此类病灶均表现强化,最典型为环形强化、强化环完整或呈不完整弓形,即使病灶较大仍具有上述特点。慢性病灶也可分为两种,一种为大体对称性的病灶,分布于两侧脑室旁,另一种病灶分布较分散,额、顶叶,侧脑室旁及脑干等处都有,病灶呈小条、片状,部分融合成较大片状。慢性病灶有收缩感,边缘较锐利,信号较均匀,周围无晕环征象,增强后无强化。结论　脑部MS有多种MRI表现,部分征象具有特征性。     

轻度创伤性脑损伤后脑组织微环境变化:多模态磁共振成像研究

目的探讨弥散张量成像(DTI)联合磁共振波谱(MRS)及磁敏感加权成像(SWI)的功能磁共振成像方法,在评估轻度创伤性脑损伤(mTBI)脑组织代谢及微结构变化的应用价值,为临床制定相应的治疗方案提供影像学参考。方法纳入21例mTBI患者和16例健康志愿者,mTBI患者在伤后4～72 h内接受T1WI、T2WI、FLAIR、DTI、MRS及SWI序列扫描,通过各序列图像及参数值评估mTBI患者伤侧脑组织和对照组内囊前肢、内囊后肢、胼胝体膝部、胼胝体压部、扣带回、半卵圆中心、额叶白质及视辐射的差异。结果两组FA值比较,仅胼胝体压部差异有统计学意义(P0.01)。mTBI组胼胝体膝部NAA/Cr值低于对照组,差异有统计学意义(P0.01)。mTBI组内囊后肢和胼胝体膝部Cho/Cr值均高于对照组,差异均有统计学意义(P0.05或0.01)。结论 FA值及NAA、Cho、Cr值能测定mTBI后脑组织水分子扩散及代谢情况,DTI联合MRS及SWI可以作为一项客观指标,定量评估mTBI患者的病情及预后。     

Magnetic resonance imaging of neural transplants in rat brain using a superparamagnetic contrast agent

Rat fetal brain tissue was incubated in vitro with superparamagnetic ferrite particles covalently coupled to the lectin wheat germ agglutinin (WGA) and transplanted into the adult rat striatum. At 6 days and at 3 weeks post-surgery the transplants were observed on T1 weighted magnetic resonance (MR) images of the rat head as an area of relatively low signal intensity which could be clearly differentiated from the higher signal intensity produced by the host brain. Histological analysis revealed that the ferrite particles were largely restricted to the transplant in a patchy distribution. The ferrite particles were associated with cells having an apparent normal morphology. Superparamagnetic ferrite particles act as potent MR contrast agents and can be used to label transplanted cells. The labeled cells are apparently not adversely affected by the WGA-ferrite particles and can be monitored for at least three weeks in vivo using noninvasive MR imaging.     

脑静脉窦血栓形成患者磁共振成像与磁共振静脉血管成像联合诊断的价值

目的：探讨脑静脉窦血栓（cerebral venous sinus thrombosis ,CVST ）形成患者磁共振成像与磁共振静脉血管成像联合诊断的价值。方法选取脑静脉窦血栓患者40例进行分析。诊断过程中,全体患者均接受磁共振（magnetic resonance venography ,MR）平扫,数字减影血管造影（digital subtraction angiography ,DSA）检查12例,MRV检测6例,增强扫描22例。结果单一横窦受累6例,上矢状窦、乙状窦及横窦受累8例,单一乙状窦受累16例,横窦和上矢状窦联合受累10例。所有患者磁共振成像（magnetic resonance venography ,MRI）及磁共振静脉成像（magnetic resonance venography ,MRV）均表现出信号改变。22例患者增强扫描显示脑静脉非正常强化,但静脉窦内部血栓未强化。M RV检查6例患者及DSA 12例患者的结果显示其受累静脉窦不明显、狭小、不规则,且出现侧支血管形成现象。结论 M RI与M RV联合诊断对于脑静脉窦血栓形成的诊断具有较好效果。     

脑功能磁共振成像研究进展

主要综述fMRI产生的历史、成像原理、成像技术和方法、已经取得的成绩以及将来研究发展的方向等。fMRI产生技术广泛应用的20世纪90年代,主要受快速成像技术的影响,从有创走向无创,从而受到神经、认知和心理科学领域的极大关注。fMRI原理是根据神经元兴奋后局部氧耗与血流增幅不一致,而BOLD效应机制成像,间接显示神经元活动。成像主要采用平面回波成像（EPI）和快速小角度激发（FLASH）技术、二者在时间和空间分辨率上各有优劣。最后几年来,fMRI技术对脑功能的研究已取得了巨大的成绩,估计将在这一领域继续拥有非常重要的地位。将来fMRI可能主要在BOLD效应的生理过程、临床应用以及高场磁体的应用等领域进一步展开。     

分裂样障碍患者的脑磁共振成像分析

目的　探讨分裂样障碍患者与正常对照者脑形态的差异。方法　采用三维磁共振成像技术测量64例(男女各32例)分裂样障碍患者和64名(男女各32名)对照组的脑形态,径线测量采用秋野等方法。结果　(1)两组男性比较:与对照组比较,患者组右侧颞叶长径小[ ( 63 4±1 5 )mm],海马角大[ (38 7±1 7)°];左侧海马长径小[ (39 4±0 7)mm],海马角大[ (38 6±1 5)°],均P<0 05。两侧半球比较,患者组右侧半球长径( 159 5±2 1 )mm、顶枕叶长径( 54 4±1 3 )mm均小于左侧[分别为(160 7±2 3)mm和(55 8±1 1)mm],而右侧半球横径[ ( 71 1±1 0 )mm]、颞叶长径[ (63 4±1 5)mm]和海马长径[ (40 7±0 8 )mm]则大于左侧[分别为( 69 8±1 0 )mm、( 62 0±1 2)mm、(39 4±0 7)mm;P<0 05]。(2)两组女性比较:患者组右侧半球高径[ (106 9±1 5)mm]、颞叶长径[ (61 6±1 2)mm]、顶枕叶长径[ (50 8±1 3)mm]和海马长径[ ( 39 9±0 8 )mm]均小于对照组[分别为(109 0±1 4)mm、(62 0±1 1)mm、(51 5±1 1)mm、(41 3±0 9)mm;均P<0 05]。两侧半球比较,患者组右侧额极长径[ ( 34 9±0 9 )mm]、额叶长径[ ( 60 7±0 9 )mm]和颞叶长径[ (61 6±1 2)mm]均大于左侧[分别为(33 6±0 8)mm、(59 6±0 8)mm、(59 9±1 3)mm],顶枕叶长径[ (50 8±1     

MR imaging of acquired fetal brain disorders

Introduction Acquired fetal brain disorders represent the third indication of fetal brain MRI, after ventricular dilatation and malformations of the central nervous system.Discussion MRI is an adequate imaging technique for evaluating fetal brain damage. Fetal brain response to brain injury may be acute, chronic or a combination of acute and chronic. An acute response is not as common in the fetal brain as in the postnatal period. A chronic response or the combination of chronic and acute response are the most common responses of the fetal brain to injury, whatever its origin. MRI also provides the natural history of acquired fetal brain lesions with regard to the stage of development.     

磁共振成像脑微出血与抗栓治疗脑出血相关

目的 观察脑微出血是否与抗栓治疗颅内出血(ICH)相关。方法 选择本院从2005年6月至2010年6月共43例抗栓治疗的脑出血患者,选择同期年龄、性别、高血压史相匹配的非抗栓治疗的脑出血患者及无脑出血史的抗栓药物使用患者作对照。结果 抗栓治疗脑出血组较无脑出血史的抗栓药物组更易发生脑微出血[31/43(72.1％)与12/57(21.1％),x2=6.731,P=0.011],抗栓治疗脑出血组较非抗栓治疗脑出血组更易发生脑微出血[31/43 (72.1％)与17/48 (35.4％),x2 =4.971,P=0.030]。脑叶微出血在抗栓治疗脑出血组为27/43(62.8％),而在非抗栓治疗脑出血组为19/48 (39.6％),两组比较差异有统计学意义(x2=4.019,P=0.042)。脑微出血数目是抗栓治疗脑出血的危险因素（OR=1.38,95％CI 1.07～1.71,t=0.806,P=0.021）。结论 脑微出血与抗栓治疗脑出血相关。     

精神分裂症脑萎缩的MRI研究

目的 了解精神分裂症患者的脑萎缩是疾病初期即已发生，还是随病程逐渐进展。方法 研究对象选取符合DSM-Ⅲ精神分裂症诊断标准的住院患者95例，正常对照组20例，按规定序列作头颅核磁共振扫描，测定第三脑室宽度、两侧第三脑室距脑岛面距离及两侧尾状核头部宽度。并以病程5年为限，分为短病程组和长病程组。结果 ①病例组第三脑室显著增宽，尾状核头部缩小。②短病程组与长病程组各组值无显著性差异。③病程与第三脑室宽度、两侧第三脑室距脑岛面距离及两侧尾状核头部宽度均无显著相关性。结论 精神分裂症患者脑萎缩明显，且与病程、服药无关，在疾病早期即已发生。     

Prenatal diagnosis of periventricular hemorrhage by fetal brain magnetic resonance imaging

Following the incidental diagnosis of triventricular hydrocephalus in a fetus 34 weeks after the mother's last menstrual period, during an uneventful pregnancy, 1.5-T brain magnetic resonance (MR) was carried out. A subependymal hemorrhage, which had not been revealed by transabdominal ultrasound, was found; this finding was confirmed by neonatal brain ultrasound and MR. Fetal MR allowed identification of the hemorrhage as the cause of the hydro-cephalus and also established its time of occurrence. Unexplained hydrocephalus should be included among the indications for fetal MR. Received: 15 June 1998     

Advanced application of magnetic resonance imaging in human brain science

Magnetic resonance imaging (MRI) has revolutionized the practical demands of clinical neurology. This technology promises now to advance neurology in theoretical and applied relams of fundamental human brain science. We emphasize here two domains in which these advances will occur. The first is volumetric morphometry of the human brain. With MRI the multiple levels of processing of the brain may be characterized in terms of their absolute volumes and their relative sizes, perspectives indispensable for our understanding of the development and operation of neural systems. Volumetric morphometry also promises substantial increases in the specificity and sensitivity of neurological diagnosis, particularly where applied to disorders where structural abnormalities will be reflected only in volumetric abnormalities. The second direction of advance considered here is application of MRI in cortical mapping in support of cognitive neuroscience. In this application MRI provides means to map at high resolution the distribution of subcomponents of neural systems activated by behavioral paradigms. This line of investigation will carry forward rapidly our understanding of how the information processing algorithms of the brain are mapped upon the coordinates of the various gray matter structures of the brain. Among the practical consequences of this application will be a reasoned design of surgical field in tumor and epilepsy surgery.     

精神分裂症脑结构的核磁共振研究

目的：采用核磁共振技术（MRI）分析精神分裂症患者的脑结构改变。方法：以精神分裂症住院患者101例为对象,正常30例为对照,作头颅核磁共振扫描。结果：病例组第三脑室显著增宽,尾状核体积较大,海马增厚,各部位海马信号强度减弱。结论：精神分裂症患者脑萎缩明显,尾状核增大。     

磁共振弥散加权成像评价机械性取栓的实验研究

目的 应用磁共振弥散加权成像(DWI)技术评价机械性取栓治疗栓塞性脑梗死的疗效。 方法 40只新西兰兔颈内动脉注入血凝块栓子制备急性栓塞性脑梗死模型后按随机数字表法分为非治疗组（不做任何治疗）、6h机械取栓组、8h机械取栓组、12h机械取栓组（分别于制模成功后6h、8h、12h在DSA导引下经股动脉插管机械取栓）,每组10只,各组分别在6h、8h、12h、24h行DWI并计算各时段表观弥散系数(ADC)和梗死体积。 结果 兔脑梗死超急性期（6 h内）均在DWI上显示缺血区,表现为高信号,在T1WI、T2WI上表现为正常信号;T1WI、T2WI及DWI对急性期(24h内)脑梗死的检出率差异有统计学意义(P＜0.05)。非治疗组、12h机械取栓组在急性期内ADC值逐渐降低,梗死体积逐渐扩大,而6h、8h机械取栓组在急性期取栓后ADC值逐渐上升,梗死体积缩小。梗死后24h,与非治疗组和12h机械取栓组比较,6h和8h机械取栓组ADC值较高,梗死体积较低,差异均有统计学意义(P＜0.05)。 结论 栓塞性脑梗死早期机械性取栓效果显著,DWI是动态观察急性脑梗死治疗效果的敏感影像学手段。     

肝豆状核变性的脑MRI与临床表现的相关分析

目的探讨肝豆状核变性（ｈｅｐａｔｏｌｅｎｔｉｃｕｌａｒｄｅｇｅｎｅｒａｔｉｏｎ，ＨＬＤ）的脑ＭＲＩ表现特点与ＨＬＤ病程及神经体征间有无相关性，以及ＭＲＩ是否有助于ＨＬＤ的诊断。方法对１６例具有角膜Ｋ－Ｆ环阳性、锥体外系体征以及生化检验异常的ＨＬＤ患者进行了头部ＭＲＩＳＥ序列横轴面和矢状面扫描。结果异常信号多呈长Ｔ１长Ｔ２且分布广泛，对称出现，Ｔ２加权像低信号为本病较具特征性的改变，病变分布以豆状核、丘脑及脑干为显著，其分布与某些神经体征有很好的相关性，但与病程间无相关性。结论ＭＲＩ有助于ＨＬＤ的诊断。     

Muscle magnetic resonance imaging of denervation and reinnervation: correlation with electrophysiology and histology

A signal increase in denervated muscle on magnetic resonance imaging (MRI) has been described in several clinical and experimental studies. Here, we studied the time course of T2-relaxation time changes in denervation and subsequent reinnervation in a rat model and correlated the findings with electrophysiology and quantitative histology. A prolongation of the T2 relaxation time in muscles was present 48 h after denervation, which was paralleled by spontaneous activity on electromyography (EMG). Histologically, there was a marked enlargement of the capillaries at that time point, indicating increased blood volume. The relaxation time changes peaked 3 weeks after beginning of nerve regeneration identified by EMG. Subsequently, the T2 prolongation normalized until 10 weeks after beginning of regeneration which was associated with a histological regression of the capillary enlargement. MRI closely mirrors the electrophysiological changes following denervation and reinnervation and may thus be used as adjunct to electrophysiology. The pathophysiological basis for the MR relaxation time changes is predominantly the enlargement of the capillary bed.     

大鼠视觉皮层动态锰离子增强磁共振功能成像研究

目的 应用动态锰离子增强磁共振技术行大鼠视觉皮层功能成像,为神经系统功能的研究提供方法.方法 成年雄性Wistar大鼠6只,右颈外动脉插管后于连续的4个时段分别进行不同处理,第一时段(5 min)不给予药物,无视觉刺激;第二时段(10 min)经右颈外动脉注射甘露醇和氯化锰,无视觉刺激;第三时段(15 min)仅注射氯化锰,给予视觉刺激;第四时段(5 min)注射氯化锰与谷氨酸混合液,无视觉刺激.每一时段处理后立即进行大鼠头颅磁共振成像,应用SPM软件进行图像的配准和平滑处理,应用Matlab软件得出图像的配色图及等高线图;选取视觉皮层进行兴趣区(ROI)分析,观察不同处理后磁共振图像中脑内特异性增强区域并比较大鼠视觉皮层的信号强度.结果 磁共振图像分析显示第一、二时段处理后大鼠脑内未发现特异性增强区域,第三时段处理后大鼠右侧视觉皮层特异性增强,第四时段处理后大鼠右侧脑内多个核团特异性增强;ROI分析显示第三时段处理后的视觉皮层信号强度(1.897±0.172)明显强于第二时段(1.549±0.163),差异有统计学意义(P<0.05).结论 动态锰离子增强磁共振成像技术能分析大鼠视觉皮层功能活动,可做为研究神经系统功能的新方法.