多体素H-MRS在脑胶质瘤术前评价中的应用

目的运用多体素二维磁共振波谱法（H-MRS）分析脑胶质瘤周围区域。H-MRS代谢物改变特点,评价H-MRS在脑胶质瘤术前的应用价值。方法收集经手术及病理证实的28例胶质瘤患者,所有患者在术前均行磁共振头颅常规检查和。H-MRS检查。分别测量不同区域的N-乙酰天门冬氨酸（NAA）、肌酸（Cr）、胆碱（Cho）峰下面积,计算出NAA／Cr、Cho／Cr及NAA／Cho比值,并进行统计学分析。结果低／高级别胶质瘤肿瘤组织和对侧正常脑组织的NAA／Cr、Cho／Cr及NAA／Cho比值存在显著性差异;低／高级别胶质瘤肿瘤组织和远瘤周区域的NAA／Cr、Cho／Cr及NAA／Cho比值存在显著性差异;低级别胶质瘤远瘤周区域和对侧正常脑组织的NAA／Cho比值存在显著性差异,NAA／Cr、Cho／Cr比值不存在显著性差异;高级别胶质瘤远瘤周区域和对侧正常脑组织的Cho／Cr、NAA／Cho比值存在显著性差异,但NAA／Cr比值不存在显著性差异。结论多体素H-MRS可帮助临床医生在术前评价胶质瘤的浸润范围,并制定最佳的治疗方案。     

胶质瘤磁共振波谱研究进展

医学磁共振应用技术包括磁共振成像(MRI)和功能磁共振(functional MRI，fMRI)，后者包括磁共振波谱(magnetic resonance spectroscopy，MRS)、弥散加权成像(diffusion weighted imaging，DWI)、灌注加权成像(perfusion weighted imaging，PWI)和皮层激发功能定位成像等。胶质瘤是一类起源于神经上皮组织的肿瘤，在颅内各类型肿瘤中发病率为第一位。目前还没有一种临床和组织学标记物能评价其病理分     

氢质子磁共振波谱成像在脑胶质瘤诊断中的研究进展

正脑胶质瘤是最常见的原发性脑肿瘤[1],常弥漫性侵及周围正常的脑组织,对放、化疗不敏感[2]。氢质子磁共振波谱成像(proton magnetic resonancespectroscopy,1H-MRS)是目前能无创性地检测人体组织代谢、生化改变及化合物定量分析的医学影像技术,可检测多种微量代谢物。1H-MRS应用探测到的化学位移现象分析组织分子结构,直观显示正常     

脑胶质瘤的^1H磁共振波谱特点及临床意义

目的探讨人脑胶质瘤质子磁共振波谱（^1HMRS）的特点及临床意义。方法22例脑胶质瘤患者术前行MRI检查的同时作^1HMRS分析,并以20例对侧正常的相应部位作为自身对照,比较N-乙酰门冬氨酸（NAA）、胆碱（Cho）、肌酸（cr）和乳酸（Lac）以及Cho／Cr、NAA／Cr、NAA／Cho比值的变化。结果与对照脑区比,脑胶质瘤在^1HMRS上均表现为明显增高的Cho峰（P〈0．01）,NAA、Cr峰下降或消失（P〈0．05）,Cho／Cr比值升高,NAA／Cr比值降低（P〈0．05）;它们的变化并与肿瘤不同病理级别密切相关,其差异具有显著性（P〈0．05）。结论 ^1HMRS是研究脑胶质瘤物质和能量代谢的有效方法,能为脑胶质瘤的临床诊断提供帮助。     

1H磁共振波谱在脑胶质瘤伽玛刀术后的应用

脑胶质瘤是起源于神经外胚层组织的恶性肿瘤，手术切除是临床上治疗该类肿瘤的主要方法，而γ-刀治疗是胶质瘤术后最常用的辅助治疗手段。质子磁共振波谱（proton magnetic resonance spectroscopy，^1H-MRS）是一项新近发现的技术，已经逐渐被应用于脑肿瘤疗效的评价。本文旨在探讨^1H-MRS技术对于脑胶质瘤γ-刀治疗后疗效监测及评价的价值和意义。     

胶质瘤瘤周水肿的磁共振波谱和弥散张量成像研究进展

脑胶质瘤占颅内肿瘤的45%～50%,是中枢神经系统最常见的恶性肿瘤[1],其死亡率也在颅内肿瘤中居首位.胶质瘤易复发,预后差.尽管采用手术、放疗、化疗等综合治疗方法,由于肿瘤呈浸润性生长,与周围组织边界不清,根治困难,尤其对于功能区的胶质瘤,既要保全功能,又要尽可能多的切除肿瘤组织,如何掌握切除范围仍然存在困难.因此,在术前正确判断肿瘤的性质、部位、病理学级别及其与周围重要组织的关系显得尤为重要.目前磁共振技术已迅速发展,磁共振波谱(MRS)和弥散张量成像(DTI)已广泛应用于胶质瘤的诊治中,从而提高了手术切除率,改善了患者的生存质量.     

大鼠脑胶质瘤磁共振波谱与组织学对照研究

目的 通过建立SD大鼠脑胶质瘤模型,应用磁共振波谱(MR Spectroscopy,MRS)进行分析,并与病理图片进行对照,研究不同阶段鼠脑胶质瘤的MRS表现及其病理学基础.方法 SD大鼠30只,随机分为3组(每组10只):1周组、2周组、3周组分别于C6细胞种植前及种植后相应时间进行MR检查 ;MR检查序列包括轴位常规MRI(T1WI、T2WI、T1WI+C)、单体素1H MRS.C6细胞种植于单侧尾壳核.所有实验鼠按照组别均于第二次磁共振检查后立即处死,并将整个鼠脑做病理片.利用工作站后处理软件测量肿瘤的NAA/Cr、Cho/Cr值,分析不同时期胶质瘤的MRS表现特点.结果 C6细胞种植后1～3周,肿瘤实质细胞数明显增长,与种植前比较,差异有统计学意义(F=20.986,P<0.05);而肿瘤中央在种植后3周出现实质细胞坏死、崩解;肿瘤区NAA/Cr值在种植后1～2周逐渐降低,Cho/Cr值升高;种植后3周,肿瘤区Cho/Cr峰更高(F=25.829,P<0.05),且肿瘤区出现脂峰(Lip).结论 C6胶质瘤细胞种植后,随着时间的推移,肿瘤实质细胞明显增多,同时Cho/Cr显著升高,NAA/Cr逐渐降低,种植后期肿瘤出现Lip峰.     

磁共振波谱分析在脑胶质瘤分级中的应用价值

目的分析氢质子磁共振波谱(~1H-MRS)分析在脑胶质瘤分级中的应用价值。方法回顾性分析我院2013-01—2016-06收治的经术后病理或活组织病理检查确诊的36例脑胶质瘤患者的临床资料,均行常规磁共振(MRI)及~1H-MRS检查,依据世界卫生组织(WHO)2007年分级方法分为低级别胶质瘤组(n=15)和高级别胶质瘤组(n=21),对比分析2组肿瘤占位核心实质区、瘤周区域及对侧镜像区胆碱复合物(Cho)、N-乙酰-L-天门冬氨酸复(NAA)、肌酐(Cr)脂质(Lip)、乳酸(Lac)。结果所有患者肿瘤占位核心实质的Cho/Cr比值均较对侧镜像区升高,NAA/Cr、NAA/Cho比值较对侧镜像区降低(P0.05)。高级别胶质瘤NAA/Cho比值低于低级别胶质瘤,而Cho/Cr高于低级别胶质瘤(P0.05)。高级别胶质瘤瘤周区域Cho/Cr比值较对侧镜像区升高,NAA/Cho比值较对侧镜像区降低(P0.05);低级别胶质瘤瘤周区域Cho/Cr比值较对侧镜像区升高,NAA/Cr、NAA/Cho比值较对侧镜像区降低(P0.05)。高级别胶质瘤组20例出现Lac峰,14例出现Lip;低级别胶质瘤组6例出现Lac峰,1例出现Lip峰。Cho/Cr比值与病理级别呈正相关(r=0.812,P0.05),而NAA/Cho比值与病理级别呈负相关(r=-0.634,P0.001),NAA/Cr与病理级别无明显相关性(r=-0.060,t=0.241)。结论氢质子磁共振波普能够有效显示脑胶质瘤患者肿瘤周围水肿区及肿瘤实质区的代谢变化情况,可为胶质瘤临床术前分级提供客观依据,提高诊断的准确性。     

轻度阿尔茨海默病患者磁共振成像及磁共振氢质子波谱研究

目的　探讨磁共振成像 (magneticresonanceimaging,MR)及磁共振氢质子波谱 (1H magneticresonancespectroscopy ,1H MRS)对轻度阿尔茨海默病 (Alzheimerdisease ,AD)患者的早期诊断。方法　对 18例临床确诊轻度AD患者和 2 0名正常对照者的MR及1H MRS进行分析 :MR上观察两组的海马回钩间距 (AB)及同层颅腔左右径 (CD)并计算两者间 (AB/CD)的比值 ;对两组额、颞叶区行1H MRS检测 ,得到N 乙酰天门冬氨酸 (N acetylaspartate ,NAA)峰、肌酸 (creatine ,Cr)峰、胆碱 (choline ,Cho)峰的积分值及计算NAA/Cr、NAA/ (Cr Cho)。对 2组检测值 ( x±s)行t检验。结果　AD组的AB =(2 7 5 3± 2 1)mm ,AB/CD =(0 2 2± 0 0 5 )mm及额、颞叶的NAA分别是 32 74± 4 72和35 38± 3 5 2 ,颞叶的NAA/Cr=2 4 6± 0 4 3,与正常对照组比较均有统计学差异 (P <0 0 5 )。用ROC法找出诊断阈值并联合应用诊断早期AD ,敏感性为 87% ,特异性为 94 %。结论　海马回钩间距及其与同层颅腔左右径比值的增大 ;额、颞叶NAA的减少 ,尤其是颞叶NAA的减少有助于对轻度AD患者的早期诊断。     

代谢综合征脑磁共振波谱和弥散张量成像的相关性研究

目的了解代谢综合征(MS)患者脑细胞代谢及神经纤维微结构的变化。方法研究对象分为MS组15例,其中男性4例、女性11例;年龄47~70岁,平均年龄(62.60±6.74)岁。对照组17例,其中男性5例、女性12例;年龄50~69岁,平均年龄(58.41±5.52)岁。均予以一般项目及头颅MRI、磁共振波谱(MRS)及MR弥散张量成像(DTI)检查,分析两组N-乙酰天冬氨酸(NAA)、乙酰胆碱(Cho)、肌酸(Cr)及部分各向异性(FA)值检查结果。结果 MS组NAA/Cr、NAA/Cho明显降低,Cho/Cr明显升高;FA值明显降低;NAA/Cr与糖尿病、低密度脂蛋白相关,FA值与高血压病、高脂血症、肥胖相关;NAA/Cr、NAA/Cho与MS病程年限相关(均P<0.05)。结论病程5年以上的MS患者脑细胞代谢及神经纤维微结构已有损害,其程度与代谢异常程度及病程明显相关。     

磁共振弥散成像在超急性缺血性脑梗死诊断中的研究

目的评价磁共振扩散加权成像（DWI）和表观扩散系数（ADC）图对超急性期脑梗死的诊断价值。方法对17例以卒中样发病6h以内、临床怀疑脑梗死的患者进行单次激发平面回波DWI和常规T2WI扫描,测定梗死灶和对侧相应部位正常脑组织的ADC值。结果DWI上表现为高信号,ADC图上表现为低信号,病灶ADC值较对侧相应区域明显下降者,诊断为脑梗死阳性,共15例,其最终临床诊断均为超急性脑梗死;阴性2例,其最终临床诊断均为短暂性脑缺血发作。DWI和ADC图诊断超急性期脑梗死的敏感性和特异性均为100％,比常规T。wI有更高的敏感性与特异性。结论DWI和ADC图对超急性期脑梗死的诊断中发挥重要作用。     

Significance of diffusion-weighted imaging and apparent diffusion coefficient maps for the evaluation of pyogenic ventriculitis

OBJECTIVE: The aim of this study is to assess the significance of an apparent diffusion coefficient (ADC) modality for the diagnosis and follow-up evaluation of ventriculitis. PATIENTS AND METHODS: Twelve patients with ventriculitis were enrolled in this study. Diffusion-weighted (DW) magnetic resonance images (MRI) and ADC maps of the periventricular white matter, intraventricular collections detected in the third or lateral ventricles and normal cerebrospinal fluid (CSF) were obtained. The images and ADC data from each lesion were correlated and then compared amongst the different lesions. CSF studies were performed via external ventricular drain (EVD) catheters or lumbar punctures performed on the same day as ADC mapping. Linear regression was used to analyze relationships among pleocytosis, glucose, chloride, protein content of pus, and ADC counting. RESULTS: A total of 24 ADC values for intraventricular pus and CSF findings were obtained from 12 patients and analyzed. The DW MRI showed marked hyperintensity in purulent lesions, and the corresponding ADC maps revealed prominent hypointensity and decreased ADC values in dependent CSF compared with non-dependent CSF and normal white matter. Dependent CSF is defined as the CSF which is mixed with purulent discharge which is located at the lower portion of the ventricle by gravity. The correlations between ADC counting and pleocytosis, and also protein content were strong: r(2)=-0.84, r(2)=-0.62, respectively (p<0.001). CONCLUSION: A decreased ADC value and increased signal intensity of dependent intraventricular fluid by DW MRI suggests the presence of material with restricted water diffusion in the ventricular space. This is seen in pyogenic ventriculitis when water diffusion is restricted in suppurative fluid. ADC counting is negatively correlated with pleocytosis and the protein content of CSF. Therefore, the ADC value might be a useful non-invasive method for the follow-up evaluation of ventriculitis as well as the diagnosis of it.     

The influence of preischemic hyperglycemia on acute changes in the apparent diffusion coefficient of brain water following global ischemia in rats

We report the effect of increased plasma glucose levels on changes in the apparent diffusion coefficient of brain water (ADCw) during the first few minutes of global ischemia in rats. Brain ADCw values were acquired every 15 s using a diffusion-weighted line-scan MR pulse sequence. Preischemic hyperglycemia was achieved by infusion of 50% dextrose (i.v.) prior to KCl-induced cardiac arrest global ischemia. Analysis based on single voxels (3.4 μl) in brain demonstrated significant differences in the time course of ADCw decline between normoglycemic (n=8) and hyperglycemic (n=6) groups. Mean data from the hyperglycemic group indicated a biphasic decline of ADCw that was characterized by an initial rapid drop followed by a plateau of approximately 1 min before gradually declining and leveling off to its minimum value. In the normoglycemic group, ADCw declined to the same value as in the hyperglycemic group, but without a notable plateau. In the cerebral cortex, the times to maximal and half maximal ADCw drop following global ischemia in the hyperglycemic group were 3.96 and 2.26 min respectively. Corresponding time intervals for the normoglycemic group were 1.86 and 1.14 min, respectively. The time course for changes in ADCw demonstrated here is significantly different than that for anoxic depolarization reported under similar experimental conditions and suggests that events other than the complete loss of membrane ionic homeostasis and subsequent cell swelling may be involved in the initial decline of ADCw in global cerebral ischemia.     

Distinguishing ischemic stroke from the stroke-like lesions of MELAS using apparent diffusion coefficient mapping

We report two patients with migraine, acute visual field defects and other neurological symptoms who were found to have high T(2) signal and FLAIR abnormalities on brain MRI in temporal and parieto-occipital regions. In these patients, the apparent diffusion coefficient (ADC) of their lesions was increased, distinguishing these lesions from those of ischemic stroke. Both were ultimately diagnosed with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS). We conclude that conventional MRI when used with diffusion-weighted MR imaging may be invaluable in detecting mitochondrial-related CNS dysfunction.     

ADC直方图在高级别胶质瘤与脑单发转移瘤鉴别中的应用价值

目的 探讨表观扩散系数（ADC）直方图鉴别高级别胶质瘤（HGG）与单发脑转移瘤（SBM）的价值。方法 回顾性分析病理或临床随访证实的7例HGG与19例SBM（腺癌脑转移瘤11例,鳞癌脑转移瘤8例）的MRI资料,测量瘤体和瘤周水肿区ADC直方图参数,利用受试者工作特征曲线评价ADC直方图参数鉴别HGG与SBM的诊断效能。结果 HGG瘤体ADC第5、25百分位数（ADC_5th、ADC_25th）及瘤周水肿ADC最小值（ADCmin）均明显低于SBM（P<0.05）,而瘤体体素计数明显高于SBM（P<0.05）。鳞癌脑转移瘤瘤体ADC_5th、ADC_25th均明显低于腺癌脑转移瘤（P<0.05）。瘤体ADC_5th=926×10-6 mm2/s鉴别诊断HGG与SBM的效能最高。结论 ADC直方图有助于HGG与SBM的鉴别诊断,瘤体ADC_5th鉴别诊断HGG与SBM的效能最高。     

扩散加权成像的表观扩散系数对兔早期后循环缺血模型的评价

目的探讨磁共振扩散加权成像（diffusion weighted imaging,DWI）的表观扩散系数（apparent diffusion coefficient,ADC）对兔早期后循环缺血模型的评价。方法16只新西兰大白兔随机平均分为假手术组和三血管结扎组。两组分别于术前及术后15min、30min、1h、1.5h、2h行磁共振DWI检查,并测量ADC值。于最后一次检查完后,每组各取6只动物分别取相同兴趣区（region of interest,ROI）：2只行病理检查,2只行电子显微镜检查,2只行2,3,5-三苯基氯化四氮唑（2,3,5-triphenyl tetrazolium chloride,TTC）染色。结果两组动物DWI均无异常高信号,但三血管结扎组ADC值与对照假手术组相比在2h时降低（P〈0.01）。病理检查无异常,电镜检查：细胞器发生异常改变,细胞轻度水肿,但无神经元坏死的结构改变,TTC染色正常。结论利用DWI之ADC值可以评价三血管结扎法是否造成兔早期后循环缺血,是进行活体评价后循环缺血的可靠指标。     

ADC直方图鉴别脑转移瘤病理性质的价值

目的 探讨ADC直方图在腺癌脑转移瘤和鳞癌脑转移瘤鉴别诊断中的价值。方法 回顾性分析经病理证实的48例脑转移瘤（腺癌31例,鳞癌17例）术前磁共振弥散加权成像,绘制整个肿瘤的ADC直方图,并计算出最小ADC值（ADCmin）、最大ADC值（ADCmax）、平均ADC值（ADCmean）、第5百分位数（ADC_5th）、第25百分位数（ADC_25th）、中位数（ADC_50th）、第75百分位数（ADC_75th）、第95百分位数（ADC_95th）。结果 腺癌脑转移瘤ADCmin、ADCmean、ADCmax均明显高于鳞癌脑转移瘤（P<0.05）,但是两种性质脑转移瘤ADC_5th、ADC_25th、ADC_50th、ADC_75th、ADC_95th均未见显著性差异（P>0.05）。根据ROC曲线分析结果,以ADCmin=0.600×10-3 mm2/s为阈值鉴别腺癌脑转移瘤和鳞癌脑转移瘤时,诊断效能最佳,ROC曲线下面积最大,为0.700,诊断灵敏度为64.7%,特异度为74.2%。结论 ADC直方图可以提供肿瘤的整体信息,有助于鉴别诊断腺癌脑转移瘤与鳞癌脑转移瘤。     

MRI影像组学模型预测脑胶质瘤IDH-1基因突变和Ki-67表达水平的价值

目的 探讨MRI影像组学模型预测脑胶质瘤IDH-1基因突变和Ki-67表达水平的价值。方法 回顾性分析2017年1月至2021年6月经术后病理证实的77例胶质瘤的临床资料,其中72例IDH-1基因检测结果完整（IDH-1组）,75例Ki-67检测结果完整（Ki-67组）。基于MRI T2WI序列选择感兴趣区域,运用Python提取影像组学特征,先用两独立样本t检验进行筛选,再用LASSO回归进一步筛选特征值。使用随机森林和参数优化后的支持向量机两种分类器建立影像组学模型,绘制受试者工作特征曲线,并计算曲线下面积判断模型预测IDH-1基因突变和Ki-67表达水平的灵敏度、特异度。结果 IDH-1组t检验筛选出47个特征,再通过LASSO回归筛选出11个特征。Ki-67组t检验筛选出17个特征,再通过LASSO回归筛选出10个特征。支持向量机和随机森林两种方法建立的影像组学模型预测胶质瘤IDH-1基因突变和Ki-67表达水平均有较高的预测效能,预测准确率均超过88.0%。结论 MRI影像组学模型对预测胶质瘤IDH-1基因突变和Ki-67表达水平具有较高的应用价值,为胶质瘤术前预测提供了新思路。     

Time course of NAA T2 and ADC(w) in ischaemic stroke patients: 1H MRS imaging and diffusion-weighted MRI

Background and purpose: Proton spectroscopy and quantitative diffusion-weighted imaging (DWI) were used to investigate the pertinence of N-acetyl aspartate (NAA) as a reliable marker of neuronal density in human stroke. Methods: The time courses of tissue water apparent diffusion coefficient (ADC_w) and metabolite T2 were investigated on a plane corresponding to the largest area of cerebral infarction, within and outside the site of infarction in 71 patients with a large cortical middle cerebral artery territory infarction. Results: Significant reductions are seen in NAA T2 deep within the infarction during the period comprised between 5 and 20 days postinfarction; the relaxation times appearing to normalise several months after stroke. After an acute reduction in ADC_w, the pseudonormalisation of ADC_w occurs at 8–12 days after the ischaemic insult. The minimum in N-acetyl aspartate T2 relaxation times and the pseudonormalisation of ADC_w appear to coincide. Conclusions: The data suggest that modifications in the behaviour of the observed proton metabolites occur during the period when the vasogenic oedema is formed and cell membrane integrity is lost. For this reason, NAA may not be a reliable marker of neuronal density during this period.