帕金森病的扩散张量成像研究

目的 研究帕金森病(PD)患者锥体外系和部分功能区的扩散张量成像(DTI)参数变化及其与PD的关系.方法 PD患者30例作为研究组,按Hoehn-Yahr分级量表将20例双侧症状患者作为中晚期PD组,10例单侧症状PD患者作为早期PD组.选取年龄和性别匹配的健康志愿者30名作为对照组.所有受试者均接受常规MR头部平扫和DTI检查.在FA图和ADC图上测量各兴趣区(双侧黑质、红核、苍白球、壳核、尾状核、丘脑、胼胝体膝部、胼胝体压部、扣带回、额叶白质和中央前回)的FA值和ADC值,并进行统计分析.结果 PD组的黑质、尾状核、丘脑和胼胝体压部的FA值较对照组明显减低(P<0.05);中晚期PD组的中央前回的FA值较对照组和早期PD组明显减低(P<0.05),中晚期PD组的扣带回的FA值低于对照组(P<0.05);中晚期PD组、早期PD组与对照组其余兴趣区的FA值差异无统计学意义;PD病变的严重程度与黑质FA值呈负相关(r=0.039,P=0.025).3组之间各兴趣区的ADC值差异无统计学意义,但随着病情级别的增加,ADC值呈增高趋势.结论 黑质、尾状核、丘脑和胼胝体压部的FA值有助于PD的早期诊断;DTI可为PD的在体研究提供更多与病理机制和临床表现有关的有价值信息.     

Comparative study of 3D-SPGR vs 2D-SE T1WI after enhancement in the brain

Summary:The utility of three-dimensional spoiled gradient recalled acquisition in steady state(3D-SPGR)imaging in the cerebral diseases was evaluated and 3D-SPGR after enhancement in depictingcontrast enhancement of all lesions and 2D-SE T1WI comparatively analyzed.117 patients were sub-jected to MRI by a GE.1.5T MR system.After performance of axial T1WI and T2WI in all pa-tients,MRA(3D-MOTSA)images were acquired in 6 cases(8 lesions)of aneurysms.After en-hancement,3D-SPGR images were obtained in all the remaining patients.Quality parameters(SNR,C and CNR)were calculated on enhanced 2D-SE T1WI and 3D-SPGR images.And a four-pointscale was used to measure the signal intensity of the main lesions on both sequences,then statisticalanalysis of the average score was performed with“t” test.Except for aneurysms,2D-SE T1WI de-tected 134 lesions and 3D-SPGR disclosed 147 lesions.It was found that there was no statistically sig-nificant difference between the two average scores as determined by the“t”test(t=1.     

Superparamagnetic Iron Oxide Labeling of Neural Stem Cells and 4.7T MRI Tracking in vivo and in vitro

Neural stem cells were labeled with superparamagnetic iron oxide (SPIO) and tracked by MRI in vitro and in vivo after implantation. Rat neural stem cells were labeled with SPIO combined with PLL by the means of receptor-mediated endocytosis. Prussian blue staining and electron mi-croscopy were conducted to identify the iron particles in these neural stem cells. SPIO-labeled cells were tracked by 4.7T MRI in vivo and in vitro after implantation. The subjects were divided into 5 groups, including 5×105 labeled cells cultured for one day after labeling, 5×105 same phase unla-beled cells, cell culture medium with 25 μg Fe/mL SPIO, cell culture medium without SPIO and dis-tilled water. MRI scanning sequences included T1WI, T2WI and T2WI. R2 and R2 of labeled cells were calculated. The results showed: (1) Neural stem cells could be labeled with SPIO and labeling efficiency was 100%. Prussian blue staining showed numerous blue-stained iron particles in the cyto-plasm; (2) The average percentage change of signal intensity of labeled cells on T1WI in 4.7T MRI was 24.06%, T2WI 50.66% and T2WI 53.70% respectively; (3) T2 of labeled cells and unlabeled cells in 4.7T MRI was 516 ms and 77 ms respectively, R2 was 1.94 s-1 and 12.98 s-1 respectively, and T2 was 109 ms and 22.9 ms, R2 was 9.17 s-1 and 43.67 s-1 respectively; (4) Remarkable low signal area on T2WI and T2WI could exist for nearly 7 weeks and then disappeared gradually in the left brain transplanted with labeled cells, however no signal change in the right brain implanted with unlabeled cells. It was concluded that neural stem cells could be labeled effectively with SPIO. R2 and R2 of labeled cells were increased obviously. MRI can be used to track labeled cells in vitro and in vivo.     

幕上中枢神经系统胚胎源性肿瘤NOS型的MRI分析

目的分析探讨中枢神经系统胚胎源性肿瘤,NOS(CNS embryonal tumour,not otherwise specified)的MRI影像特点,以提高对本病的认识。方法回顾性分析14例经手术及病理证实的幕上中枢神经系统胚胎源性肿瘤,NOS型的MRI及临床、病理资料并复习文献。结果所有病例均为单发,8例累及两个以上的脑叶;9例直径大于5 cm,平均直径5.4 cm;灶周水肿表现为较轻(5/14),甚至无(5/14);病灶呈囊实性多见(12/14);5例可见到多囊结构,形成所谓"肠襻"状改变;在T_1WI(10/14)、T_2WI(11/14)图像上信号混杂,流空(5/14)与出血(6/14)信号较常见;增强后呈花环状或结节中重度强化(13/14)。结论幕上中枢神经系统胚胎源性肿瘤NOS临床、病理及影像学特点可参照CNS PNET的临床、病理及影像学特点,MRI表现具有体积大、信号混杂等特点,有助于其诊断与鉴别。     

颞叶癫痫的质子磁共振波谱与PET/CT及术后病理对照研究

目的：对颞叶癫痫患者术前的质子磁共振波谱（1H MRS）与正电子发射断层扫描（PET/CT）、脑电图（EEG）及术后病理进行对照研究，评价1H MRS对颞叶癫痫的诊断价值。方法：16例颞叶癫痫病人，术前均做发作期间脑电图和/或长程脑电图监测及PET/CT检查。对28例健康志愿者和16例患者分别进行双侧海马的1H MRS采集，定量分析N-乙酰天门冬氨酸（NAA）、肌酸（Cr）和胆碱（Cho）代谢物的变化。3例患者手术切除致痫灶送病检。结果：病侧组、对侧组和对照组的NAA/Cr、Cho/Cr和NAA/（Cho+Cr）值之间的差异均有统计学意义（P<0.05）。16例患者中5例为单侧异常，11例为双侧异常，14例可确定异常侧，定位敏感度87%。结论：患者1H MRS示病侧与EEG、PET和病理改变有较好的对应性，1H MRS不仅可以发现双侧病变，而且可以指出病变严重的一侧，为术前致痫灶的定位提供可靠的依据。     

脑膜瘤MR扩散张量成像研究

目的探讨平均扩散系数(ADC)和各向异性分数(FA)在脑膜瘤诊断中的价值.资料与方法 28例脑膜瘤在治疗前行常规MRI及扩散张量成像(DTI).在T1WI增强、T2WI及FA图上确定肿瘤、水肿、肿瘤邻近及对侧正常白质区.测量、分析这些区域的FA值和ADC值.结果脑膜瘤Ⅰ级:水肿区ADC值高于肿瘤实体区、肿瘤邻近正常白质区及肿瘤对侧正常白质区(P<0.05).肿瘤邻近及对侧白质区FA值高于肿瘤实体区、水肿区(P<0.05).肿瘤实体区与水肿区FA值无显著性差异(P>0.05).脑膜瘤Ⅱ Ⅲ级:水肿区ADC值高于肿瘤实体区、肿瘤邻近及对侧白质区(P<0.05),实体区和肿瘤邻近及对侧白质区ADC值亦有显著性差异(P<0.05).肿瘤邻近白质区FA值高于实体区和水肿区(P<0.05).脑膜瘤Ⅰ级肿瘤实体区、水肿区、邻近白质区ADC值与脑膜瘤Ⅱ、Ⅲ间具有显著性差异(P<0.05),肿瘤邻近白质区FA值亦有显著性差异(P<0.05).结论 ADC图有助于区分肿瘤实体区和水肿区.FA图可清晰显示正常白质纤维和肿瘤的解剖关系,利于术前手术方案制定.结合常规MRI,DTI有助于脑膜瘤良、恶性分级.     

新生儿缺氧缺血性脑病MRI表现及其与预后的关系

目的 探讨足月新生儿缺氧缺血性脑病（HIE）的早期MRI表现及其与临床分度及预后的关系。资料与方法 以9例无窒息史的正常新生儿作对照,观察46例HIE患儿初期的MRI表现及28例复查病例的MRI表现。结果 （1）MRI能显示HIE患儿的12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）或硬膜下出血（SDH）3种征象在轻度组与中、重度HIE组差异无显著性（P〉0．05）;而另外6种征象（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、脑回征、灰白质分界不清及胼胝体水肿）,在中、重度与轻度HIE组差异有显著性（P〈0．05）,说明这些征象是脑损伤严重的表现。（2）双侧基底节区广泛高信号伴内囊后肢高信号消失,弥漫性脑水肿。大面积脑梗死,脑回征以及脑实质广泛出血5种早期征象提示预后不良。常常会留下神经系统后遗症。结论 MRI可以客观反映新生儿HIE早期脑损伤的严重情况,并可早期评估预后。     

基于卷积神经网络的深度学习算法对颅内出血的类型识别及血肿分割一致性的研究

目的:开发一种可以检测不同类型颅内出血并自动计算血肿体积的基于卷积神经网络的深度学习算法,探讨其识别的准确性及血肿分割的一致性.方法:数据集1纳入9594例颅脑CT平扫图像,随机选取223例颅内出血阳性患者作为颅内出血类型识别的测试集,剩余CT图像作为其训练集,评估测试集中算法识别五种不同类型颅内出血的效能.数据集2选...     

MR氧摄取分数成像在星形细胞瘤分级的应用研究

目的探究基于非对称自旋回波(ASE)序列的氧摄取分数成像(OEF imaging)定量测量胶质瘤氧摄取分数的可行性,评价相关定量指标在星形细胞瘤分级诊断中的诊断性能。材料与方法 32例经病理诊断为星形细胞瘤的患者,其中Ⅱ级16例、Ⅲ级5例、Ⅳ级11例。所有受试对象扫描前均获得书面知情同意,扫描序列包括横断面T1WI、T2WI、T2 FLAIR、增强T1WI、ASE-OEF扫描。通过在肿瘤实体区手动绘制感兴趣区的方式测量肿瘤氧摄取分数(OEF),并对肿瘤标本进行ki-67免疫组化染色。采用独立样本t检验和单因素方差分析(oneway ANOVA)评价OEF定量指标在高低级别胶质瘤中的差异并与传统的MRI比较,采用受试者工作特征曲线进行诊断性能评价,采用Pearson相关分析OEF与Ki-67标记指数之间的相关性。结果增强扫描中,16例低级别胶质瘤10例表现为不强化,6例强化;16例高级别胶质瘤中,仅有1例不强化,其余15例表现为不同程度强化,差异有统计学差异(P=0.002)。高级别胶质瘤OEF明显高于低级别组,差异具有统计学意义(17.00±2.47、20.46±2.98,P0.01)。观察者间一致性分析显示ICC=0.89,表明测量结果具有良好的一致性。Ki-67 LI在高低级别胶质瘤中分别为48±54.01、5.8±8.76,差异具有统计学意义(P=0.01);Pearson相关分析表明Ki-67 LI与OEF存在中等的相关性(r=0.406,P0.05)。依据有无强化诊断高低级别胶质瘤的曲线下面积(AUC)为0.781,敏感度和特异度分别为93.8%和62.5%;定量指标OEF的诊断效能优于增强扫描,AUC为0.852,当取阈值为19.55时有最大的诊断效能,敏感度和特异度分别为81.3%和87.5%。结论基于EPI技术采集非对称自旋回波(ASE)序列可用于无创性测量肿瘤组织氧摄取分数;定量指标OEF能良好的鉴别高低级别胶质瘤,且能一定程度上反映肿瘤的增殖活性,在胶质瘤诊疗中具有较大的潜在应用前景。     

RSNA2016中枢神经系统影像学

【摘要】RSNA2016神经系统方面科学报告的热点主要集中在拓展MRI新技术及数据分析方法,主要包括1H-MR血氧定量成像（MOXI）、酰胺质子转移成像（APT）、扩散峰度成像（DKI）、神经突方向离散度及密度成像（neurite orientation dispersion and density imaging,NODDI）等,在中枢神经系统疾病的应用研究主要包括：①1H-MR血氧定量成像（MOXI）测量人脑肿瘤氧张力（PO2）;②MK提供人神经胶质瘤的分子状态的信息;③缺血性卒中病灶酸度分级评估缺血半暗带和侧枝循环的情况;④扩散加权动脉自旋标记（DW-ASL）MRI测量内源性水渗漏评估阿尔茨海默病（AD）脑血管渗漏、定量磁化率成像（QSM）定量分析AD脑内病理性铁沉积;⑤糖尿病脑损伤的认知功能以及精神疾病功能MR成像。本文对相关内容进行简要综述。