脑多发性硬化的MRI诊断

目的:探讨脑内多发性硬化(MS)的核磁共振(MRI)诊断价值.方法:回顾性分析48例经临床确诊为MS患者的MRI表现及相关资料.48例均行MRI常规平扫,46例加做增强扫描.结果:(1)病灶多发,主要分布于侧脑室周围及额、颞、顶、枕叶皮层下白质区,部分累及胼胝体、小脑、脑干、丘脑、基底节及大脑皮质;双侧侧脑室旁可见“垂直脱髓鞘征”;(2)病灶主要以长和较长T2、略长和等T1信号为主;(3)增强扫描显示强化与不强化病灶同时存在,强化病灶呈点状、斑片及环形;少数急性起病病例病灶呈较均匀一致的强化.结论:MRI是临床诊断MS的敏感、直观、最有价值的检查手段.     

颅内血管外皮细胞瘤MRI诊断价值

目的:评价MRI对颅内血管外皮细胞瘤(intracranial hemangiopericytoma,HPC)的诊断价值.方法:回顾性分析手术、病理证实6例颅内血管外皮细胞瘤患者的MRI影像资料,研究病变基本特征、信号特点及强化方式.结果:6例均位于颅内脑外,多为不规则分叶状软组织肿物,病灶大小平均为5.3cm,占位效应明显,瘤周水肿较轻,肿瘤内均可见迂曲流空血管.病灶以等高TW2、等低TW1信号为主,4例出现囊变、坏死及出血信号.增强扫描病灶呈明显均匀强化,囊变部分无强化.结论:颅内血管外皮细胞瘤MRI表现具有一定特征性:肿瘤体积较大、多呈分叶状软组织肿块,以等TW1、等TW2信号为主,其内可见丰富血管流空、坏死及囊性变,有占位效应,但瘤周水肿不明显;增强扫描实体呈明显均匀强化,可出现“脑膜尾征”.     

MRI对卵巢成熟畸胎瘤术前诊断初步探讨

目的:探讨MRI对卵巢成熟畸胎瘤术前诊断价值及手术方式选择的指导意义.方法:回顾性分析经妇科手术治疗、病理诊断为卵巢成熟畸胎瘤58例,术前均行MRI扫描.采用自旋回波(SE)序列、快速自旋回波(FSE)序列、压脂序列、DWI序列扫描.常规行矢状面、横断面及冠状面扫描.结果:(1)病变位于右侧卵巢30例,左侧卵巢28例,双侧卵巢3例.(2)病变大小为1.2-16.7cm,边缘较清晰,形态多为类圆形.(3)病变为囊性或囊实性.其内成分多样,MRI信号显示混杂,脂肪成分MRI上T1W、T2W为双高信号,脂肪抑制序列为低信号;牙齿、毛发、软骨、纤维成分T1W、T2W为双低信号;肌肉、神经成分T1W、T2W为等信号.(4)病变小于10 cm,其内脂肪成分较多,无腹腔镜手术禁忌症患者行腹腔镜卵巢畸胎瘤切除术;病变大于10 cm,钙化、毛发等实性成分较少时,能耐受膀胱截石位,行阴式卵巢畸胎瘤切除术;病变大于15 cm,或病变较小但以钙化、牙齿、毛发等实行性成分为主,怀疑恶性卵巢畸胎瘤或者不能判断病变性质时行传统方式开腹卵巢畸胎瘤切除术.结论:MRI能较好显示卵巢畸胎瘤内部结构及成分,在临床手术术式选择方面具有指导意义.     

胰腺神经内分泌肿瘤的不典型CT、MRI征象分析

目的:分析4例胰腺神经内分泌肿瘤(P-NENs)的不典型CT、MRI影像学特征,以提高对其诊断水平.方法:对4例经手术病理证实的P-NENs的不典型CT和(或)MRI表现进行回顾性分析.结果:4例胰腺神经内分泌肿瘤患者均进行CT平扫及增强检查,平扫病变相对于正常胰腺呈等密度1例,稍低密度3例,其中1例瘤内见钙化;CT增强扫描4例均为轻～中度增强,静脉期较动脉期增强幅度稍减低,所有患者各期增强幅度均未超过胰腺实质,其中1例可见延迟期不完整包膜强化,包膜密度略高于周围胰腺.3例患者行MRI平扫、DWI及增强检查,2例肿瘤相对正常胰腺呈长T1、稍长T2信号,较均匀,1例T1WI呈不均匀稍低信号,T2WI呈较高与稍低混杂信号,CT所显示之病变内钙化T1、T2均呈较低信号.DWI序列3例病变均呈较明显高信号.增强扫描3例病变均呈轻到中度强化,2例强化较均匀,1例强化不均匀,强化幅度均未超过正常胰腺.2例MRI可见有部分包膜环形强化,略高于周围胰腺实质.结论:明显增强以及包膜强化被认为是P-NENs的典型影像学表现,但其影像学表现多样,认识其多样性及不典型影像学征象,可以提高对其诊断准确率.     

特殊病因所致可逆性后部白质脑病综合征的临床研究

目的:探讨特殊原因所致可逆性后部白质脑病综合征的临床和影像学的特点。方法:收集2008年3月至2014年12月年我院临床确诊的9例RPLS患者病例,回顾分析RPLS的病因、临床表现、影像特点及预后。结果:本组9例RPLS患者病因较少见,包括系统性红斑狼疮病1例、肺癌术后2例、肾移植术后1例、Miller-fisher综合征1例、Ig A肾病1例、慢性淋巴细胞性白血病1例、干燥综合征1例、肝肾综合征1例。9例患者均以急性或亚急性起病,临床表现多样。头MRI除双侧大脑后部白质对侧T1WI呈低信号,T2WI和FLAIL呈高信号改变外,双侧基底节、侧脑室旁、丘脑、脑干、小脑、胼胝体、皮质区均可受累,且DWI呈弱信号或稍高信号,ADC呈高信号改变,符合血管源性水肿的表现。结论:RPLS的神经影像学改变除典型的后部、双侧对称的白质受累病灶外,还有一些非典型的单侧白质、特殊部位及皮质受累的表现,病变具有可逆性的特点,治疗强调针对病因、控制血压、颅压、止痉、维持离子及酸碱平衡、补液、营养及支持等处理,多数病例预后良好,少数可由血管源性水肿发展为细胞毒性水肿,造成不可逆性损害。     

新生儿缺氧缺血性脑病MRI表现及病理基础与预后评估

目的:探讨新生儿缺氧缺血性脑病(HIE)的MRI表现及病理基础与预后评估。方法:回顾性分析42例HIE患儿初期的MRI表现。结果:MRI能显示HIE患儿的9种早期异常征象,其中T1WI皮层高信号,侧脑室周围深部白质高信号以及蛛网膜下腔出血(SAH),硬膜下出血(SDH)弥漫性脑水肿,T1WI双侧基底节高信号伴内囊后肢高信号消失,弥漫性脑实质出血,灰白质分界不清,大面积脑梗死,后五种征象提示预后不良,常会留下严重神经系统的后遗症;侧脑室周围病变一般会影响小儿运动功能。结论:MRI可以客观反映新生儿HIE早期脑损伤的严重程度,并可早期评估预后。     

巨大淋巴结增生症的影像学诊断

目的:研究巨大淋巴结增生症(Castleman Disease)的CT和MR影像表现特点,以提高对本病的认识,提高诊断准确率。方法:收集我院自1995年1月~2012年10月间,经手术病理证实的19例巨大淋巴结增生症,患者均接受CT或MRI平扫及增强扫描检查。其中,男7例,女12例,年龄19~62岁,平均43.4岁。结果:19个病例中14例病灶位于胸部(胸腔或纵隔),2例位于颈部,3例位于腹膜后区,局限型16例,弥漫型3例。CT检查采用CT动态增强扫描技术,局限型病灶在动脉期可见明显强化,强化程度近似主动脉,弥漫型病灶在动脉期表现为中等程度强化,两者在延迟期均表现为持续强化。MR扫描:4例表现为T1WI低信号,1例为中等信号,T2WI均呈高信号,动态增强扫描病灶的强化方式与CT基本一致。结论:颈部、胸部或腹膜后区的富血供病变,在CT及MRI增强扫描动脉期表现明显强化,延迟期持续强化,应高度怀疑巨大淋巴结增生症的可能性。     

C T、常规MRI 序列和SWI 诊断弥漫性轴索脑损伤比较

目的:探讨弥漫性轴索损伤(DAI)的CT、常规MRI序列和磁敏感加权成像(SWI)表现与诊断价值。方法:回顾分析42例DAI患者的影像资料,分析、比较CT、MRI和SWI的信号特征及脑内病灶显示率。结果:SWI显示病灶最多、最敏感;脑CT扫描次之;常规MRI序列敏感性差,只有部分病灶显示。结论:CT、MRI和SWI对DAI早期诊断、治疗及评价预后具有重要参考价值,SWI是诊断DAI最有效的首选影像学检查方法。     

脑弥漫性轴索损伤的MRI征象及与GCS计分及预后的关系

目的：探讨脑弥漫性轴索损伤（DAI）的磁共振成像（MRI）征象及其与格拉斯哥昏迷量表评分（GCS）计分和预后的关系。方 法：回顾性分析2012 年1 月-2014 年7 月我院收集的30 例DAI 患者的临床病历资料,根据病灶累及部位分析其与GCS 计分和 临床预后的关系。结果：30 例患者共53 个病灶,17例多发病灶,13 例单发病灶;42 个病灶T1WI显示出低信号或者是等信号,11 个病灶T1WI显示为高信号;T2WI显示为高信号,FLAIR 序列以及弥散加权像（DWI）上表现出的信号更高,范围更清晰;病灶形 态呈条索状27 例,斑片状11 例,卵圆形8 例,不规则斑点状7 例;病灶未累及脑中线部位的患者临床预后优于病灶累及脑中线 部位的患者,差异有统计学意义（Z=-2.636,P=0.008）,病灶累及脑中线部位的患者GCS 计分情况比未累及组严重,计分更低,差 异有统计学意义（Z=-2.519,P=0.012）。结论：DAI病灶累及脑中线部位的患者GCS计分较低、预后差,MRI检查是诊断DAI 首选 的影像学方法,临床有重要的参考价值。     

脑室外室管膜瘤的磁共振成像影像表现与病理特征的相关性研究

目的:研究脑室外室管膜瘤的磁共振成像(MRI)影像表现与病理特征的相关性。方法:选取2016年2月-2018年2月我院收治的脑室外室管膜瘤患者40例为研究对象。对所有患者均进行颅脑MRI平扫以及增强扫描检查,分析所有患者的临床病理特征情况,对比不同病理分级、不同病灶直径以及不同病灶部位患者的MRI表现。结果:脑室外室管膜瘤患者中病理分级为Ⅰ-Ⅱ级人数占比为75.00%,高于Ⅲ级的25.00%;病灶直径6 cm人数占比为40.00%,低于病灶直径≥6 cm的60.00%;病灶部位在幕上的人数占比为20.00%,低于在幕下的80.00%。其中21例肿瘤实质部分均呈现稍长T1和稍长T2信号,另有19例肿瘤实质部分均呈等长T1和等长T2信号;所有患者的肿瘤囊性部分均呈长T1和长T2信号。病理分级为Ⅰ-Ⅱ级患者病灶位于浅表的人数占比明显高于Ⅲ级(P0.05),病灶直径6 cm患者合并周围水肿的人数占比高于病灶直径≥6 cm患者(P0.05),病灶部位为幕上患者的MRI表现和病灶部位为幕下患者对比差异无统计学意义(P0.05)。结论:MRI应用于诊断脑室外室管膜瘤效果明显,可清晰显示脑室外室管膜瘤病灶,且患者的MRI影像表现受病理分级、病灶直径影响。     

A Longitudinal Brain Magnetic Resonance Imaging Study of Neuromyelitis Optica Spectrum Disorder

Brain involvement is commonly seen in patients with neuromyelitis optica spectrum disorder (NMOSD). However, little is known about the chronic changes of acute brain lesions on MRI over time. Here, our objective was to evaluate how acute brain MRI lesions in NMOSD changed on follow-up MRI. We reviewed the MRIs of 63 patients with NMOSD who had acute brain lesions and follow-up MRI over an interval of at least 3 months. Of the 211 acute brain lesions, 24% of lesions disappeared completely on T2-weighed images (WI) and a decrease in size ≥50% on T2-WI was observed in 58% of lesions on follow-up MRI. However, 47% of lesions revealed focal T1-hypointensity and, in particular, 18% showed focal cystic changes. Cystic changes were observed most commonly in corticospinal tract and corpus callosal lesions whereas the vast majority of lesions in the cerebellum, basal ganglia and temporal white matter resolved completely. MRI remission on T2-WI occurred in 82% of lesions, while approximately half of the lesions presented foci of T1-hypointensity, which may be considered a severe tissue injury over time. The extent of brain injury following an acute brain lesion in NMOSD may depend on the location of the lesion.     

脑卒中大鼠后室下区祖细胞和神经发生减少的神经影像研究

目的:通过神经影像学研究脑卒中大鼠后室下区祖细胞和神经发生减少的变化情况。方法:2个月龄的Wistar雄性大鼠70只随机分为2组:脑卒中大鼠模型组(n=35)和正常组(n=35)。构建脑卒中大鼠模型后通过磁共振成像系统观察大鼠祖细胞归巢情况、脑梗塞面积与对侧脑组织体积的百分比和脑白质纤维束重塑情况;采取免疫化组织方法分析大鼠血管新生和神经发生情况;利用Western Blot法分析脑组织内细胞因子及炎症因子的表达;再根据RT-PCR方法计算Neu N蛋白和GFAP蛋白表达。结果:MRI扫描于T1WI及T2WI序列下,通过所得图像及信号可知,模型组大鼠祖细胞归巢信号变化、脑梗塞面积与对侧脑组织体积的百分比和脑白质纤维束重塑情况比较间有显著差异(P<0.05),具有统计学意义。脑卒中大鼠血管新生和神经发生、细胞因子EVGF和BDNF水平、Neu N蛋白和GFAP蛋白表达均较正常大鼠低(P<0.05),而炎症因子IL-1β和TNF-α水平则相对较高(P<0.05)。结论:神经影像可用于脑卒中大鼠后室下区祖细胞和神经发生下降的研究,结合组织学分析,进一步验证了结果的可行性与有效性。     

Comparative brain stem lesions on MRI of acute disseminated encephalomyelitis, neuromyelitis optica, and multiple sclerosis

Background

Brain stem lesions are common in patients with acute disseminated encephalomyelitis (ADEM), neuromyelitis optica (NMO), and multiple sclerosis (MS).

Objectives

To investigate comparative brain stem lesions on magnetic resonance imaging (MRI) among adult patients with ADEM, NMO, and MS.

Methods

Sixty-five adult patients with ADEM (n = 17), NMO (n = 23), and MS (n = 25) who had brain stem lesions on MRI were enrolled. Morphological features of brain stem lesions among these diseases were assessed.

Results

Patients with ADEM had a higher frequency of midbrain lesions than did patients with NMO (94.1% vs. 17.4%, P<0.001) and MS (94.1% vs. 40.0%, P<0.001); patients with NMO had a lower frequency of pons lesions than did patients with MS (34.8% vs. 84.0%, P<0.001) and ADEM (34.8% vs. 70.6%, P = 0.025); and patients with NMO had a higher frequency of medulla oblongata lesions than did patients with ADEM (91.3% vs. 35.3%, P<0.001) and MS (91.3% vs. 36.0%, P<0.001). On the axial section of the brain stem, the majority (82.4%) of patients with ADEM showed lesions on the ventral part; the brain stem lesions in patients with NMO were typically located in the dorsal part (91.3%); and lesions in patients with MS were found in both the ventral (44.0%) and dorsal (56.0%) parts. The lesions in patients with ADEM (100%) and NMO (91.3%) had poorly defined margins, while lesions of patients with MS (76.0%) had well defined margins. Brain stem lesions in patients with ADEM were usually bilateral and symmetrical (82.4%), while lesions in patients with NMO (87.0%) and MS (92.0%) were asymmetrical or unilateral.

Conclusions

Brain stem lesions showed various morphological features among adult patients with ADEM, NMO, and MS. The different lesion locations may be helpful in distinguishing these diseases.     

Neuroparacoccidioidomycosis (NPCM): Magnetic Resonance Imaging (MRI) Findings

Objective

To describe the magnetic resonance imaging (MRI) patterns of the central nervous system (CNS) involvement by neuroparacoccidioidomycosis (NPCM).

Methods

Between January 1999 and March 2011, a review of MRI data analysis from 8 cases of NPCM was performed. The following MRI characteristics were examined by an experienced neuroradiologist: topography of lesions, aspects on T1- and T2-weighted images (WI), contrast enhancement, diffusion and spectroscopy.

Results

All patients had evidence of paracoccidioidomycosis infection outside the nervous system. Regarding CNS involvement, five patients had only supratentorial lesions; three had infra- and supratentorial ones. Meningeal extension occurred in three patients. The lesions were predominantly hyperintense on T1WI. At T2WI, a hypointense component was present in five cases as well as a perilesional abnormal white matter. A ring-enhancement pattern was seen in five cases. Spectroscopy was performed in three patients and showed an increased lipid peak in all of them. In one case, there was also an increased choline peak.

Conclusion

NPCM is rare, and MRI may help its differentiation from other inflammatory lesions. However, the presence of active infection outside CNS and some imaging characteristics should point to this diagnosis.     

FLAIR和DWI在急性脑梗塞中的应用

目的比较液体衰减反转恢复(FLAIR)和弥散加权成像(DWI)在急性脑梗塞中的应用。方法14例急性脑梗塞患者接受FLAIR和DWIMRI检查评价病变的显示范围,边界及对比度并计算病变区。结果FLAIR序列和DWI对病变的显示范围,均优于常规T2WI,以DWI对病变显示更佳。结论FLAIR和DWI在急性脑梗塞中均有用,以DWI最好,且能对急性脑梗塞作定量评价。     

Comprehensive brain MRI segmentation in high risk preterm newborns

Most extremely preterm newborns exhibit cerebral atrophy/growth disturbances and white matter signal abnormalities on MRI at term-equivalent age. MRI brain volumes could serve as biomarkers for evaluating the effects of neonatal intensive care and predicting neurodevelopmental outcomes. This requires detailed, accurate, and reliable brain MRI segmentation methods. We describe our efforts to develop such methods in high risk newborns using a combination of manual and automated segmentation tools. After intensive efforts to accurately define structural boundaries, two trained raters independently performed manual segmentation of nine subcortical structures using axial T2-weighted MRI scans from 20 randomly selected extremely preterm infants. All scans were re-segmented by both raters to assess reliability. High intra-rater reliability was achieved, as assessed by repeatability and intra-class correlation coefficients (ICC range: 0.97 to 0.99) for all manually segmented regions. Inter-rater reliability was slightly lower (ICC range: 0.93 to 0.99). A semi-automated segmentation approach was developed that combined the parametric strengths of the Hidden Markov Random Field Expectation Maximization algorithm with non-parametric Parzen window classifier resulting in accurate white matter, gray matter, and CSF segmentation. Final manual correction of misclassification errors improved accuracy (similarity index range: 0.87 to 0.89) and facilitated objective quantification of white matter signal abnormalities. The semi-automated and manual methods were seamlessly integrated to generate full brain segmentation within two hours. This comprehensive approach can facilitate the evaluation of large cohorts to rigorously evaluate the utility of regional brain volumes as biomarkers of neonatal care and surrogate endpoints for neurodevelopmental outcomes.     

Biofidelic white matter heterogeneity decreases computational model predictions of white matter strains during rapid head rotations

The finite element (FE) brain model is used increasingly as a design tool for developing technology to mitigate traumatic brain injury. We developed an ultra high-definition FE brain model (>4 million elements) from CT and MRI scans of a 2-month-old pre-adolescent piglet brain, and simulated rapid head rotations. Strain distributions in the thalamus, coronal radiata, corpus callosum, cerebral cortex gray matter, brainstem and cerebellum were evaluated to determine the influence of employing homogeneous brain moduli, or distinct experimentally derived gray and white matter property representations, where some white matter regions are stiffer and others less stiff than gray matter. We find that constitutive heterogeneity significantly lowers white matter deformations in all regions compared with homogeneous properties, and should be incorporated in FE model injury prediction.     

肾嗜酸细胞腺瘤的影像学诊断

目的:探讨螺旋CT和MRI对肾嗜酸性细胞腺瘤的诊断及鉴别诊断的价值。方法:回顾性分析12例肾嗜酸性细胞瘤的CT和/或MRI表现。结果:CT检查12例,平扫8例病灶呈均匀软组织密度影,3例呈不均匀软组织密度影,1例瘤体周边有环状钙化。增强后病灶轻中度强化,6例见星状瘢痕。MRI检查3例,2例T1WI呈等低信号、T2WI呈高信号;1例T1WI呈等信号、T2WI等低信号。结论:多数肾嗜酸细胞腺瘤的影像学表现具有一定特征性。CT结合MRI特别是动态扫描有助于术前做出正确的诊断。     

Self-antigen tetramers discriminate between myelin autoantibodies to native or denatured protein

The role of autoantibodies in the pathogenesis of multiple sclerosis (MS) and other demyelinating diseases is controversial, in part because widely used western blotting and ELISA methods either do not permit the detection of conformation-sensitive antibodies or do not distinguish them from conformation-independent antibodies. We developed a sensitive assay based on self-assembling radiolabeled tetramers that allows discrimination of antibodies against folded or denatured myelin oligodendrocyte glycoprotein (MOG) by selective unfolding of the antigen domain. The tetramer radioimmunoassay (RIA) was more sensitive for MOG autoantibody detection than other methodologies, including monomer-based RIA, ELISA or fluorescent-activated cell sorting (FACS). Autoantibodies from individuals with acute disseminated encephalomyelitis (ADEM) selectively bound the folded MOG tetramer, whereas sera from mice with experimental autoimmune encephalomyelitis induced with MOG peptide immunoprecipitated only the unfolded tetramer. MOG-specific autoantibodies were identified in a subset of ADEM but only rarely in adult-onset MS cases, indicating that MOG is a more prominent target antigen in ADEM than MS.