高分辨磁共振评价年龄对动脉粥样硬化性大脑中动脉狭窄血管重构和斑块负荷的作用

目的 分析高分辨磁共振（HRMRI）评价年龄对动脉粥样硬化病大脑中动脉狭窄血管重构和斑块负荷的作用。方法 选择2018年5月至2019年12月在茂名市人民医院进行治疗的200例大脑中动脉粥样硬化患者作为研究对象,依据年龄大小,将其分为中青年组（年龄<60岁）与老年组（年龄≥ 60岁）,每组100例。两组患者均实施HRMRI检查,并在HRMRI T1加权成像轴位图像中测量大脑中动脉最狭窄部位、参考部位血管面积和管腔面积,同时计算两组患者大脑中动脉狭窄程度、斑块负荷百分比、偏心指数以及阴性重构情况。结果 老年组患者斑块负荷百分比为（41.00±13.00）%,高于中青年组,阴性重构率为14.00%,低于中青年组,差异均有统计学意义（P<0.05）。Pearson相关性分析结果显示,年龄与患者斑块负荷百分比呈正相关（r=0.581,P=0.013）。结论 动脉硬化患者大脑中动脉斑块负荷及重构方式与年龄有一定关联,通过HRMRI技术能够较好地进行评价。     

动脉粥样硬化斑块的磁共振成像

磁共振成像 (MRI)是一种较为理想的和具有广泛应用前途的非创伤性检查技术。动物模型和临床应用结果证明 ,多序列MRI能确定动脉粥样硬化斑块的形态、大小、病理构成及其稳定性。正在研究开发的血管内MRI(IVMRI)在显示动脉壁厚度及斑块的特征方面有重要价值。MRI造影增强的T1加权像 (T 1WI)能较清楚地使斑块本身、炎性斑块以及斑块中的纤维蛋白和血栓强化。MRI还可作为动脉粥样硬化斑块治疗前、后疗效随访的重要监测手段     

大脑中动脉粥样硬化狭窄重构模式、斑块内出血与脑卒中风险的关系

目的 探讨大脑中动脉(middle cerebral artery,MCA)粥样硬化狭窄管壁重构模式、斑块内出血与急性脑卒中风险的关系.方法 回顾性分析行颅脑3D-TOF MRA检查发现MCA高度狭窄(狭窄率≥70％)127例患者的临床资料及高分辨率磁共振成像(HR-MRI)表现,评价MCA狭窄段血管壁的重构模式、斑块内出血与临床事件的关系.结果 130支MCA主干高度狭窄(症状组54支,无症状组76支).症状组MCA狭窄段正性重构41支,非正性重构13支;无症状组MCA狭窄段正性重构18支,非正性重构58支,两者差异有统计学意义(x2=34.76,P＜0.01).16支MCA斑块内出血(发生率12.31％,症状组13支,无症状组3支).症状组与无症状组斑块内出血的发生率差异有统计学意义(24.07％ vs 3.95％,x2=11.85,P=O.001).结论 正性重构模式及MCA斑块内出血可能增加同侧MCA供血区急性脑卒中风险.     

基底动脉粥样硬化性梗死的分类与血管形态学异同的探讨

目的 应用高分辨率磁共振(HR-MRI)管壁成像技术研究基底动脉粥样硬化性梗死两种类型——穿支闭塞型病变(BOD)和非穿支闭塞型病变(non-BOD)的血管重构与斑块特征.方法 将32例症状性基底动脉狭窄患者分为BOD 18例,non-BOD 14例.应用3.0T HR-MRI对基底动脉进行管壁增强扫描,然后使用CMRtools软件对血管狭窄最严重的层面的管壁及斑块面积等参数进行测量,研究血管的重构和斑块特征.结果 HR-MRI管壁成像结果显示,non-BOD组血管狭窄程度较BOD组更明显[(68.9％±19.1)％ vs (43.8％±18.8)％,P=0.017].正性重构更常见于non-BOD (57.2％ vs16.7％,P=0.036).BOD组管壁面积指数小于non-BOD组(P＜0.001).两组血管强化均以偏心性为主,两组斑块强化比例差异无统计学意义(P=0.196),但BOD组强化程度小于non-BOD组[(39.9±23.2)％ vs (65.3±21.1)％,P=0.004].结论 基底动脉BOD梗死和non-BOD型梗死在血管重构和斑块性质方面的特征各不相同.     

MRI检测兔动脉粥样硬化斑块的实验研究

目的:探讨将MRI应用于兔动脉粥样硬化斑块的检测并对其成分进行定性分析的可行性.方法:应用高胆固醇饮食建立兔动脉粥样硬化模型.采用T1WI、T2WI、PDWI、TOF序列分别对实验动物进行扫描,同时对实验动物进行B超检查.结果:成功建立兔动脉粥样硬化模型;MR图像T1WI、T2WI、PDWI表现为兔动脉管壁增厚,斑块呈等信号、高信号或低信号,与病理切片检测结果符合率较高;MR成功检测斑块并分析其成分;与超声比较,MR具有较高的准确性.结论:MR可以检测兔动脉粥样硬化模型的斑块并进行定性分析.     

颈动脉粥样硬化斑块的磁共振成像诊断

应用高场强磁共振设备及多种线圈、多序列扫描技术探测颈动脉粥样斑块,不仅能观察到斑块内脂核含量和纤维帽的厚度,斑块内出血、坏死等变化,还可以得到血管管壁形态学的改变、血管管腔及斑块自身的应力改变等多方面的信息;通过钆螯合对比剂及超顺磁性三氧化二铁制剂增强成像,可以了解斑块内炎性改变,这与斑块的发展和预后密切相关。因此,通过磁共振成像技术判定颈动脉粥样斑块的稳定性具有重要的临床意义。     

高分辨率磁共振成像与CT血管造影评价大脑中动脉狭窄和斑块性质的效果对比

目的 比较高分辨率磁共振成像(HR-MRI)与CT血管造影(CTA)对大脑中动脉狭窄和斑块性质的评价效果.方法 选取20例经数字减影血管造影(DSA)确诊大脑中动脉狭窄的患者,均行HR-MRI和CTA检查,比较两种方法对大脑中动脉狭窄的诊断效能及对斑块性质的评估效果,并评价两种方法与DSA评价管腔狭窄程度的一致性.结果 DSA显示共24支大脑中动脉发生血管狭窄.CTA与HR-MRI对大脑中动脉狭窄的检出率、诊断大脑中动脉狭窄的灵敏度、特异度及准确性比较,差异均无统计学意义(P>0.05).在评价血管狭窄程度方面,HR-MRI与DSA呈高度一致性(κ=0.770,P=0.016),CTA与DSA呈中度一致性(κ=0.528,P=0.031).HR-MRI对大脑中动脉斑块的总检出率及易损斑块、稳定斑块的检出率均高于CTA(P<0.05).结论 HR-MRI在评估大脑中动脉狭窄和斑块性质方面比CTA更具优势.     

MRI不同序列对颈动脉粥样硬化斑块成分分析

目的探讨MRI不同序列对颈动脉粥样硬化斑块成分脂核、出血、钙化显示能力,以利于诊断及优化序列。方法使用3.0T MRI扫描仪对35例患者进行平扫及增强扫描,分别统计TOF、T1W、T2W、PDW及CE-T1W对斑块成分-脂核、出血、钙化显示的阳性及阴性例数,随后统计5序列显示斑块成分的阳性例数及阴性例数,并以此为标准,计算各序列显示斑块各种成分的敏感性、特异性及κ值。结果共发现74个斑块,其中68个斑块纳入分析,57个斑块中存在脂核,出血斑块30个,43个斑块有钙化。对于脂核的显示,以CE-T1W较好,敏感性、特异性及κ值分别为100%、90.9%和0.944。对于出血的显示以T1W最佳,敏感性、特异性及κ值分别为100%、92.1%和0.911。而TOF显示钙化能力最强,敏感性、特异性及κ值分别为100%、92%和0.936。结论对于脂核的显示,以CE-T1W显示最佳,有很高的敏感性及特异性。T1W与TOF对于判断斑块内出血的存在,与标准有极好的一致性。而TOF能够准确判断斑块表面钙化及较小钙化的存在。TOF、T1W和CE-TIW序列组合能够很好地判断斑块脂核、出血及钙化。     

Diffusion weighted magnetic resonance imaging for acute stroke: practical and popular

Aim

To evaluate the feasibility and impact of diffusion weighted magnetic resonance imaging (DW MRI) as the first line neuroimaging of stroke at a district general hospital.

Methods

Prospective audit of all in‐patients admitted with clinically suspected acute stroke and referred for imaging over a consecutive 17 week period. The data collected included scan type, time from cerebral event to imaging request, and time from formal radiological request to neuroimaging. Clinicians'' (general physicians, neurologists, and radiologists) perceptions were assessed by a questionnaire.

Results

148 patients had neuroimaging for clinically suspected stroke during this period. Eighty one per cent of patients (120 of 148) had DW MRI as first line. Ninety two per cent of these patients had DW MRI within 24 hours of the formal radiological request. Twenty eight patients did not undergo DW MRI because lack of MRI safety, clinical state, unavailability because of maintenance service or lack of trained staff. Clinicians found the introduction of the DW MRI based service a significant improvement on computed tomography, especially for equivocal cases.

Conclusion

DW based MRI service is both feasible and sustainable in the setting of a district general hospital and most clinicians feel that this is a significant improvement to stroke services.     

Detection of atherosclerotic plaque progression in the abdominal aorta of rabbits with 3T magnetic resonance imaging

Background  With features of high tissue contrast, MRI can be used for the qualitative and quantitative evaluation of atherosclerosis plaques. In this study we investigated the development of atherosclerosis plaque with high resolution 3T MRI in a rabbit model and compared the findings with the histopathological results.

Method  Twenty male New Zealand white rabbits were randomly allocated into an experimental group (n=16) and a control group (n=4). Atherosclerotic lesions were induced in the abdominal aorta by balloon injury and cholesterol feeding. Multiple sequences MRI examination (ToF, T1WI, T2WI, and CE T1WI) were performed at the 2nd, 3rd, and 4th months after aortic denudation. Vessel wall thickness, total vessel area, lumen area, and vessel wall area were recorded. Plaque components were analyzed using histological results as a standard reference.

Results  Seventeen rabbits (14 in the experimental group and 3 in the control group) received all three MR examinations. Gradually, from 2 months to 4 months, vessel wall thickness and area in the experimental group increased significantly compared with the control group (P <0.01). In the lumen area progressive stenosis was not found, even a slight dilation had developed in the experimental group. Lipid, fibrotic and calcified plaques can be differentiated by MR image. According to histological results, MRI had good performance in detection of lipid plaque.

Conclusion  MRI can be used to monitor progression of atherosclerosis and differentiate plaque components.

     

三维高分辨率磁共振血管壁成像用于研究颅内动脉粥样硬化斑块强化与缺血性卒中的关系

 目的   分析三维高分辨率磁共振(high-resolution magnetic resonance imaging,HR-MRI)血管壁成像技术用于评价颅内动脉粥样硬化斑块强化的可重复性,并探讨斑块强化特点与缺血性卒中的关系。方法   收集52例因颅内动脉粥样硬化导致的缺血性卒中患者,行3.0 T常规头颅MRI、三维时间飞跃法磁共振血管造影及HR-MRI扫描,将每例患者的斑块分为责任斑块与非责任斑块。责任斑块为梗死灶供血动脉上唯一的斑块或最狭窄处的斑块,非责任斑块为非供血动脉上的斑块及梗死灶供血动脉上非最狭窄处的斑块。由两名观察者独立判断斑块的强化等级,应用Mann-Whitney U检验统计分析两组斑块强化等级和斑块处血管狭窄率的差异,应用二分类Logistic回归分析法研究斑块强化等级与责任斑块的关系。结果   52例缺血性卒中患者中颅内动脉粥样硬化斑块共118个,其中责任斑块52个,非责任斑块66个。责任斑块组中,40个斑块明显强化,9个轻度强化,3个无强化;非责任斑块组中,4个斑块明显强化,24个轻度强化,38个无强化。观察者内与观察者间对斑块强化等级评价一致性高(Kappa＞0.75)。责任斑块组斑块强化等级(Z=-7.787,P<0.01)和斑块处血管狭窄率(Z=-5.327,P<0.01)均大于非责任斑块组,二分类Logistic回归结果显示斑块明显强化为责任斑块的独立影响因素(OR:74.3,95%CI:15.0～367.1,P<0.01)。结论   三维HR-MRI评价颅内动脉粥样硬化斑块强化的可重复性好;斑块强化多见于责任斑块,可能是发生缺血性卒中的重要危险因素。     

Dysembryoplastic neuroepithelial tumors: magnetic resonance imaging and magnetic resonance spectroscopy evaluation

Background Dysembryoplastic neuroepithelial tumor （DNT） is a rare benign neoplasm of the central nervous system affecting young people. A correct preoperative diagnosis is helpful for planning surgical strategies and improving prognosis. The purpose of this study was to characterize DNTs using magnetic resonance imaging （MRI） and magnetic resonance spectroscopy （MRS） and to analyze the value of these two techniques in the diagnosis of DNTs. Methods MR images of 13 patients with DNTs were reviewed retrospectively; and five of the patients also underwent MRS. Tumors were confirmed by surgery. The distribution, extension and signal features of the lesions were assessed, and the MRS results were analyzed. Results All tumors were supratentorial. The cortex was the main area involved, with nine tumors located in the temporal lobe, three in the frontal lobe, and one on the boundary between the temporal and occipital lobes. All cases had decreased signal intensity on Tl-weighted MR images and increased signal intensity on T2-weighted images. On fluid attenuated inversion recovery weighted images, the hyperintense ＂ring sign＂ and internal septation of the lesion were seen in 9 cases. Eight tumors had well-demarcated borders. Peritumoral edema or mass effect was absent in all cases. A contrast enhancement examination was performed in 9 cases. Contrast enhancement was absent in five cases, and four cases showed significant enhancement. The MRS showed a low N-acetylaspartate peak and a lack of elevated choline-containing component （Cho） or Cho-Cr ratio （Cho/Cr） in five patients. Conclusions The MRI findings of DNTs were stereotypical. The combination of MRI and MRS techniques were helpful in making a correct presurgical diagnosis.     

Dynamic contrast-enhanced magnetic resonance perfusion weighted imaging in astrocytomas： correlation with histopathology and immunohistochemistry

Objective： To investigate magnetic resonance perfusion weighted imaging and its relationship with the grading and the expression of vascular endothelial growth factor （VEGF） and angiogenesis in astrocytomas. Methods： A collection of 34 patients with astrocytomas proved by surgery and pathology were examined by magnetic resonance imaging（MRI）, with 26 cases of grade Ⅰ-Ⅱ （low-grade） and 8 cases of grade Ⅲ-Ⅳ （high-grade）. MR perfusion images were obtained with spin-echo echo planar imaging （SE-EPI） techniques. Expression of VEGF was examined by immunohistochemical method of streptavidin-biotin-peroxidase（SP）. The vascular development was measured by micro-vascular density （MVD） which was immunostained with anti-factor Ⅷ-related antigen monoclonal antibody. Results： Both of the expression of VEGF and the angiogenesis in 34 cases of astrocytomas were significantly correlated to the maximum relative cerebral blood volume （Max rCBV） （r=0.604, P〈0.001; r=0.625, P〈0.001, respectively）. The Max rCBV and the expression of VEGF, MVD in high-grade astrocytomas were significantly higher than that of in low-grade astrocytomas （t=3.0, P=0.017; t=7.08, P=0.01; t=3.37, P=0.011, respectively）. Conclusion： MR perfusion weighted imaging might be a valuable method in in vivo study of the angiogenesis of astrocytomas and evaluating their malignant degree and prognosis.     

3.0T高分辨率磁共振成像评估大脑中动脉粥样硬化狭窄的可信度

目的 探讨3.0 T高分辨率磁共振成像(HR MRI)评估大脑中动脉粥样硬化性狭窄的可信度.方法 2011年2月～2013年12月,对66例经DSA确诊的动脉粥样硬化性MCAM1段中重度狭窄(50％～99％)患者进行HR MRI检查,测定MCA最狭窄处管腔面积(lumen area,LAnarrow)、血管面积(vessel area,VAnarrow)及参考血管LAreference及VAreference,分析MCA斑块分布部位(前壁、后壁、上壁、下壁);比较2位研究者的定量测量及定性分析结果,对比分析其中一位研究者首次及1个月后的再次分析结果;ICC法分析观察者自身差异及不同观察者间差异.结果 HR MRI测量VAnarrow、AVreference、LAreference具有非常好的组间(ICC 0.801、0.843、0.808)及组内一致性(ICC 0.811、0.916、0.958);LAnarrow测定结果的一致性一般(ICC 0.584、0.625),要差于其他3个指标.HR MRI判断有无斑块的一致性非常好(ICC0.917、0.960);HRMRI判定MCA不同部位(上壁、下壁、前壁、后壁)斑块的组间(ICC 0.856、0.836、0.791、0.905)、组内(ICC 0.876、0.827、0.825、0.950)一致性较好.结论 基于HR MRI的MCA粥样硬化性狭窄定量、定性分析具有较好的可重复性,但对血管最狭窄处的定量分析可信度仍有待提高.     

大脑胶质瘤病的磁共振及磁共振波谱诊断价值

目的探讨磁共振成像(MRI)和磁共振波谱成像(MRS)对大脑胶质瘤病的诊断价值。方法对13例经手术或活组织病理检查证实的大脑胶质瘤病患者的临床表现及MRI平扫、增强、MRS影像学资料进行回顾性分析。MRI常规行T1加权像(T1WI)、T2加权像(T2WI)及液体衰减反转恢复序列(FLAIR),采用时间飞跃法(TOF)的磁共振血管成像(MRA)、T1WI增强扫描。氢质子MRS采用单体素激励回波探测法(STEAM),并分析N-乙酰天门冬氨酸(NAA)、肌酸(Cr)、胆碱复合物(Cho)等物质峰值改变。结果所有病例均侵犯2个或2个以上脑叶,以颞叶、枕叶、胼胝体、基底节和丘脑等部位侵犯受累常见。病变区T1WI呈低或等信号、T2WI呈高或混杂高信号、液体衰减反转恢复序列上为高信号,未见明显坏死、钙化,受累区域脑组织肿胀,占位效应轻。注射钆喷酸葡胺增强扫描示,9例无明显强化,2例斑片状强化,1例结节状强化,1例线状轻度强化。病变区域MRS表现为不同程度NAA降低,NAA/Cr比值降低;Cho上升,Cho/Cr和Cho/NAA比值上升。结论 MRI结合MRS对大脑胶质瘤病的诊断及鉴别诊断具有较大临床价值,是目前诊断大脑胶质瘤病的首选影像学方法。     

中枢神经细胞瘤磁共振成像及氢质子磁共振波谱的诊断价值

目的 探讨中枢神经细胞瘤(CNC)的常规磁共振成像(MRI)和氢质子磁共振波谱(1H MRS)的表现特征和诊断价值.方法 回顾性分析5例经手术病理证实的CNC进行常规MRI检查,其中4例加做多体素1H MRS,并分析其MRI及1H MRS表现.结果 5例CNC患者肿瘤特征性位于侧脑室,邻近Monra孔并累及透明隔.在T1加权成像4例呈等低不均匀信号,1例呈等高不均匀信号;T2加权成像呈等高不均匀信号;增强后肿瘤呈中度及明显不均匀强化.4例1H MRS均表现为胆碱峰明显增高,N-乙酰门冬氨酸(NAA)峰下降,胆碱/肌苷比值升高,NAA/肌苷比值降低.结论 20~40岁的患者发生于侧脑室透明隔处邻近Monra孔的肿瘤,结合其MRI及1H MRS表现特征应考虑到CNC诊断.     

基于模糊增强的磁共振成像PROPELLER采样数据优质重建算法

目的 提出一种基于模糊增强的重建算法,以改进PROPELLER采样数据中现有重建算法的不足.方法 由每个K空间带补零重建出临时图像,然后提出模糊增强算法,增强后在图像域进行运动参数估计,进行运动补偿后由网格化重建算法重建出结果图像.结果 该算法对于运动参数估计的精度更高,对刚性运动伪影的消除效果明显优于现有算法.结论 该算法可以显著提高PROPELLER采样数据重建图像质量.