磁敏感加权成像在出血性脑梗死诊断中的初步应用

目的探讨磁敏感加权成像（SWI）诊断出血性脑梗死的临床价值。方法20例亚急性期出血性脑梗死患者分别行常规MRI、扩散加权成像（DWI）和SWI检查,根据图像分析结果比较不同扫描序列所显示的梗死灶内出血灶数目及其阳性检出率;测量SWI序列出血最大层面出血灶面积和T2WI序列梗死灶最大层面的梗死灶面积,并行相关分析;观察SWI序列对梗死灶内静脉血管的显示程度,以及梗死灶以外区域微出血灶的诊断敏感性。结果20例患者SWI序列均显示梗死灶内出血,两名医师共诊断43个出血灶,其中SWI序列显示42个、T1WI序列25个、DWI序列15个、T2WI序列12个;SWI序列阳性检出率与T1WI、T2WI、DWI序列相比,差异具有统计学意义（X^2=51．516,P=0．000）。T2WI序列梗死灶最大层面的梗死灶面积为（18．08±12．47）cm^2,SWI为（5．02±6．27）cm^2,梗死灶面积与出血灶范围之间呈明显正相关（r=0．562,P=0．010）。其中,13例患者SWI序列检出梗死灶以外区域的微出血灶;12例显示梗死灶内小静脉血管分支减少和（或）变细,6例血管增多、增粗和（或）扭曲。结论SWI序列对出血性脑梗死病灶内出血的显示优于常规MRI和DWI序列,并能显示梗死灶内静脉血管的变化及梗死灶以外区域的微出血灶,可作为诊断出血性脑梗死的MRI常规扫描序列。     

功能MRI诊断单纯疱疹病毒性脑炎一例

目的评价功能磁共振在单纯疱疹病毒性脑炎中的诊断价值。方法本例患者女性,45岁,行CT、MRI常规扫描及核磁血管成像、弥散加权成像、灌注成像,结合实验室检查、临床表现诊断单纯性疱疹性病毒性脑炎。结果发病当日CT平扫未见异常,6天后CT平扫右侧颞叶皮层大片状低密度,MRI右侧颞叶累及皮层、皮层下白质大面积长T1长T2高Flair信号,弥散加权成像呈高信号,ADC值较对侧低22%～36%,灌注成像右颞病变相对脑血流量及体积较对侧明显增高;MRA右侧大脑中动脉血管分支明显增粗、数目增多。结论当传统CT及MRI平扫及增强扫描难以鉴别脑梗死与脑炎时,功能MRI成像有助于单纯疱疹脑炎定性诊断。     

超早期磁共振血管成像无大血管闭塞的急性缺血性卒中患者的预后

目的研究超早期磁共振血管成像(MRA)无大血管闭塞的急性缺血性卒中患者的临床结局及预测结局的因素。方法选择超早期(发病6 h内)完成急诊磁共振成像(MRI)检查且MRA无大血管闭塞的急性缺血性卒中患者31例,收集其临床及影像学数据,在MRI检查前完成NIHSS评分,随访发病后24 h的NIHSS评分及3个月时mRS评分。结果31例患者中28例MRI弥散加权成像(DWI)提示梗死灶,治疗后24 h时NIHSS显著改善者17例,3个月随访mRS0-2分者28例,未发现预测结局的因素。结论超早期MRA无大血管闭塞的急性缺血性卒中患者中大部分DWI可见责任梗死灶,即使未溶栓,大多数患者临床结局也较好。     

DWI在诊断脑梗死超急性期中的应用分析

目的探讨磁共振弥散加权成像在诊断脑梗死超急性期中的应用情况。方法选取我院2012-04—2015-04收治的66例超急性脑梗死患者为研究对象,使用磁共振弥散加权成像在不同时间点对其进行诊断,并与磁共振成像平扫的结果进行比较。结果 3组超急性脑梗死患者中病灶部位比较差异无统计学意义(χ~2=0.429,P=0.807);病灶部位在脑干、顶叶、小脑、额叶、枕叶的3组患者人数差异无统计学意义(χ~2=0.795,P=0.672);存在大面积脑梗死的3组人数差异无统计学意义(χ~2=0.214,P=0.898);在第1组患者中,使用磁共振弥散加权成像检查出患者脑部病灶18例,使用磁共振成像检出10例,差异具有统计学意义(χ~2=6.286,P=0.012);在第2组患者中,使用磁共振弥散加权成像检查出患者脑部病灶20例,使用磁共振成像检出13例,差异具有统计学意义(χ~2=5.254,P=0.022);在第3组患者中,使用磁共振弥散加权成像检查出脑部病灶19例,使用磁共振成像检出11例,差异具有统计学意义(χ~2=7.467,P=0.006)。结论对超急性期脑梗死患者使用磁共振弥散加权成像可较T2和T2FLAIR等平扫技术更早发现病变,在临床上具有较高的应用价值。     

动脉粥样硬化性大脑中动脉区域TIA功能磁共振成像分析

目的利用弥散加权成像(DWI)、磁共振血管成像(MRA)对大脑中动脉(MCA)区域TIA进行解剖性定位,评价磁共振对临床实践的指导意义。方法对32例TIA患者,在发作1.5h~7d内行头部MRI、DWI、MRA检查,对DWI图像上的高信号与T2WI像、MRA、临床症状、体征进行对照研究。结果2例DWI正常,但MRA颅内大脑中动脉闭塞,病变血管与临床症状相一致。12例DWI正常,MRA仅轻度狭窄或正常。3例DWI有高信号,T2WI无相应病灶为超早期脑梗死,其中MRA1例动脉硬化样改变,2例大脑中动脉闭塞,病灶与体征相符。15例DWI有高信号、T2WI有相应病灶,2例为早期脑梗死、13例为腔隙性脑梗死,其中MRA8例颅内大血管轻到中度狭窄,2例严重狭窄。MRI显示20例(62.5%)存在多发陈旧腔隙性梗死灶。对于TIA患者发作时MRA相应病变进行χ2四格表精确检验,DWI异常组与正常组比较P<0.05,MRA大血管病变是TIA预后形成梗死的独立危险因素。结论对TIA患者行MRI、DWI、MRA检查,能及时发现超早期脑梗死,还能对新发腔隙性脑梗死准确定位,科学指导临床早期干预治疗。MRA可提供1.2级大血管的供血状态,指导后续的2级预防。     

磁共振成像技术在缺血性脑血管病临床实践中的意义

目的:评估磁共振成像(MRI)弥散加权成像(DWI)、灌注加权成像(PWI)及磁共振血管造影术(MRA)在缺血性脑血管病临床实践中的意义。方法:对78例发病在10d内的急性缺血性脑血管病患者进行DWI、PWI及MRA检查,对不同发病时期患者的临床与影像改变进行对照研究。结果:急性/亚急性脑梗死灶,相对脑血容量(rCBV)下降,平均通过时间(MTT)延长。62例脑梗死中,41.9％有缺血半暗带,部分患者复查MRI,可发现梗死的进展;58.1％无半暗带存在。急性/亚急性梗死灶DWI表现为高信号,7例患者不同血管分布区有多发新鲜脑梗死灶,陈旧梗死灶表现为低信号。71.8％的患者MBA所显示的血管狭窄或闭塞与DWI病变一致。结论:MBA可提供大的动脉的供血状态;PWI在缺血区提供最早、最直接的血流下降情况;DWI反映脑细胞功能状态。PWI与DWI的研究可确定缺血半暗带,动态观察缺血性损害的进展,判断缺血的预后。     

急性缺血性卒中常规磁共振成像血管内高信号回顾性研究

目的 明确常规磁共振对于血管高信号的展示及其临床意义。方法 回顾总结浙江大学医学院附属第一医院2010年1-12月的急性缺血性卒中患者。所有患者均行常规磁共振检查。结果 我院神经内科共收住急性脑梗死患者280例,均符合脑血管病诊断标准。血管内异常信号患者共26例,出现率为9.29％。前循环异常信号14例,其中颈内动脉高信号11例,大脑前动脉高信号2例,大脑中动脉合并大脑前动脉高信号1例;在颈内动脉血管内高信号11例患者中,MRA证实14支颈内动脉血管狭窄,对血管病变的特异度100％,敏感度78.6％;后循环共12例,其中椎动脉高信号5例,基底动脉3例,基底动脉合并椎动脉高信号4例;1例患者未行MRA检查,11例患者MRA证实14支血管存在病变,椎动脉和基底动脉内高信号11例,特异度为100％,敏感度为78.5％。结论 常规磁共振序列对于血管内高信号的展示具有很高的临床特异度,其血管病变与MRA的结果具有一致性。     

急性卒中的磁共振成像流程探讨

目的：探讨急性卒中发生后影像学诊断的最佳流程。方法：67例发病1～72h的急性卒中患者在CT检查后行T1加权成像（T1 WI）、T2加权成像（T2 WI）、梯度回波T2^＊加权成像（GRE-T2^＊WI）和弥散加权成像（DWI）检查，39例缺血性卒中患者均行灌注加权成像（PWI）检查。结果：28例急性脑出血的出血病灶在GRE-T2^＊WI上全部清楚显影。16例TIA患者T1 WI、T2 WI和GRE-T2^＊WI以及DWI均正常，9例PWI检查灌注降低，7例正常。23例脑梗死患者中，7例发病6h内者GRE-T2^＊WI均正常，6例PWI〉DWI，1例PWI=DWI；16例发病6～72h内的患者GRE-T2^＊WI呈高信号，DWI均可见与体征相对应的高信号病灶，14例PWI=DWI，2例PWI正常。本组14例患者GRE-T2^＊WI像上在基底节区、丘脑、脑干和皮质下发现有1～18个微出血。结论：急性卒中后通过T1 WI、T2 WI、GRE-T2^＊WI、DWI和PWI检查流程可在较短时间内一站式鉴别脑出血、梗死和TIA患者，确定缺血半暗带，帮助溶栓治疗的选择。     

后循环梗死与椎基底动脉狭窄的相关性分析

目的 探讨MRI所示的后循环梗死灶与DSA发现的椎基底动脉狭窄的相关性.方法 回顾分析30例后循环梗死患者的临床资料,将每例后循环梗死患者头部MRI发现的梗死灶与DSA所见的椎基底动脉狭窄血管进行对照.结果 MRI示单发性梗死22例(其中脑干梗死10例,小脑梗死8例,丘脑梗死2例,枕叶梗死2例),多发性梗死8例.DSA...     

功能性磁共振弥散加权成像在急性脑梗死诊断中的应用价值

目的探讨功能性磁共振弥散加权成像在急性期脑梗死患者的临床诊断中的应用价值。方法回顾分析2012-08—2013-04我院接收的80例急性脑梗死患者的临床资料,应用神经解剖法和功能性磁共振弥散加权成像等技术对患者的病变部位行定位和诊断。结果功能性磁共振弥散加权成像的图像显示,急性期脑梗死患者的患侧表观弥散系数为0.389±0.092,健侧的表观弥散系数为0.955±0.112,并呈高信号,而弥散系数的图像则显示为低信号。在急性期,患者病灶的表现弥散系数与相对表现弥散系数均为下降,在慢性期则呈现出升高的趋势。结论 6h内功能性磁共振弥散加权成像技术在脑梗死的临床诊断中的效果要显著优于传统的MRI技术。     

Acute basilar artery occlusion: topographic study of infarcts

OBJECTIVE: To determine the ischemic lesions distribution and extension of patients with basilar artery thrombosis by the means of magnetic resonance imaging (MRI). METHODS: In 17 patients with thrombosis of the basilar artery, MRI was performed, including T2-weighted, magnetic resonance angiography (MRA) and diffusion-weighted imaging (DWI) sequences in the short-term phase (<48 hours). The shapes of ischemic lesions were obtained by graphic software and overlapped on a representative layer outline background. RESULTS: The MRA showed basilar artery occlusion in all cases and the DWI revealed different patterns of ischemic lesions. Most patients showed multiple lesions within the posterior circulation territory. Lesions more often occurred in pontes, cerebellums and mesencephalons than medullas, thalami and occipital lobes. Basilar pons, cerebral crus and cerebellum hemisphere were more susceptible than pontine tegmentum, vermis, midbrain tegmentum and tectum. CONCLUSIONS: When the basilar artery is occluded, basilar pons, cerebral crus and cerebellum hemisphere were most susceptible. The branches with smaller lumen of basilar artery, which are easier to be affected, are thought to be the cause of such a phenomenon.     

Magnetic resonance imaging in basilar artery occlusion

CONTEXT: Acute basilar artery occlusion has particularly high mortality and morbidity. OBJECTIVE: To determine the potential utility of advanced magnetic resonance imaging (MRI) methods, including diffusion-weighted imaging, for the early management of patients with basilar artery thrombosis. DESIGN: Case series. SETTING: Institute of Neuroradiology and Department of Neurology, Johann Wolfgang Goethe University, Frankfurt, Germany. PATIENTS: In 4 patients with occlusion of the basilar artery, MRI was performed, including T2-weighted and diffusion-weighted imaging (DWI) sequences and magnetic resonance angiography (MRA) in the short-term phase (<12 hours). Three patients underwent intra-arterial thrombolysis. Clinical outcome was obtained 10 days after symptom onset. RESULTS: The MRA was performed 3.5 to 11.5 hours after symptom onset and showed basilar artery occlusion in all cases. The DWI revealed different patterns of ischemic lesions. In 2 patients, no or only small lesions could be identified; the remaining showed multiple and large lesions within the posterior circulation territory. Initial clinical status was severely impaired in all cases (Rankin scale score, 4-5). Thrombolysis was initiated in 3 patients, leading to successful recanalization in 2. Clinical outcome was favorable in the 2 patients with small DWI lesions and successful reperfusion (Rankin scale score, 2), whereas it was worse in those with large DWI lesions and persisting occlusion (death, persisting coma). CONCLUSIONS: In critically ill patients with acute basilar occlusion, the extent of DWI lesion involvement can be highly variable. Small DWI lesions seem to be associated with a favorable outcome if reperfusion is achieved with thrombolysis. This could potentially be the case independent of time from symptom onset.     

DWI及MRA在大面积脑梗塞早期诊断中的价值

目的:评价弥散加权磁共振成像DWI和磁共振血管成像MRA对早期大面积脑梗塞的诊断价值。方法:对24例早期大面积脑梗塞的临床和磁共振资料进行分析,全部患者均行DWI及MRA检查。结果:24例早期大面积脑梗塞中,13例急性期CT扫描未检测出确切病灶,DWI扫描全部出现大片异常高信号,病灶检出率为100％。而在常规T2WI检查中,7例为阴性,病灶检出率为69％。MRA发现血管异常24例,表现为供血动脉闭塞,狭窄、硬化。结论: DWI有助于明确早期大面积脑梗塞病变范围,且能区别新旧病灶。MRA能直接显示大面积脑梗塞闭塞的供血脑血管,联合使用DWI和MRA对早期大面积脑梗塞诊断有重要的临床价值,也有利于早期合理的治疗方案制定及预后判断。     

高清磁共振研究基底动脉粥样硬化狭窄重构模式在脑桥旁正中梗死中的应用

目的 应用3.0T高分辨磁共振成像（high resolution magnetic resonance imaging,HRMRI）探讨脑桥旁 正中梗死（paramedian pontine infarction,PPI）患者基底动脉管壁特征及重构模式。 方法 连续入组孤立脑桥旁正中梗死患者30例,行头颅磁共振平扫及头颅磁共振血管成像 （magnetic resonance angiography,MRA）检查,并用3.0T HRMRI对基底动脉检查,测量管壁特征并计 算重构指数（remodeling index,RI）（最窄处血管面积/参考处血管面积）。RI≤0.95为阴性重构,RI 在 0.95～1.05之间为无重构,RI≥1.05为阳性重构,比较阴性重构和阳性重构的斑块面积、斑块负荷等 特点。 结果 30例患者在MRA上共发现9例有基底动脉狭窄,21例显示管腔正常,而在HRMRI可发现25例患 者有基底动脉粥样硬化性斑块,并可见斑块位于脑桥旁正中梗死责任血管的穿支动脉口。对HRMRI上 发现有动脉粥样斑块的25例患者计算RI,其中阴性重构8例,无重构6例,阳性重构11例,比较两组数 据,阳性重构组的斑块面积（8.17±4.7）mm2及斑块负荷（29.07±15.03）%均大于阴性重构组的斑块 面积（1.08±1.89）mm2及斑块负荷（3.96±6.76）%,差异具有显著性。 结论 HRMRI有助于缺血性卒中的病因学分型并评估病变的RI。脑桥旁正中梗死患者基底动脉阴性 重构与阳性重构同样常见,阳性重构常合并较大的动脉粥样硬化斑块,且斑块面积及斑块负荷均大 于阴性重构。     

Transient abnormalities associated with status epilepticus on diffusion-weighted MR imaging]

We report on two patients with transient abnormalities on MRI during status epilepticus(SE). Diffusion-weighted MR imaging(DWI) and T2-weighted and fluid-attenuated inversion recovery (FLAIR) MR images showed cortical and thalamic hyperintensity with swelling of the cortex. The lesions did not respect vascular territories. We also observed an increased signal in the ipsilateral middle cerebral artery on magnetic resonance angiography(MRA), and leptomeningeal enhancement on postcontrast MRI. Follow-up imaging revealed that the abnormal findings resolved within a few weeks, although a residual area of increased T2 signal intensity persisted. These findings suggest the presence of reversible cytotoxic and vasogenic edema induced by seizure. We conclude that this disorder should be taken into consideration in the differential diagnosis of other conditions, including ischemic stroke.     

The differences of clinical parameters between small multiple ischemic lesions and single lesion detected by diffusion-weighted MRI

OBJECTIVES: The cause of small infarction is mainly considered to be intracranial small-vessel disease. However, it is difficult to explain the mechanism of multiple, acute infarctions by small-vessel disease. We examined the differences of clinical parameters between patients with multiple small lesions and single lesion detected by Diffusion-weighted MRI (DWI). MATERIAL AND METHODS: We reviewed the clinical records of 86 consecutive stroke patients with lacunar size ischemic lesions on DWI during the acute stage (within 72 h of onset). The subjects were 55 males and 31 females (mean age 72.4 +/- 9.9 years). Small multiple acute ischemic lesions were defined using the following criteria 1): the lesions were detectable by DWI 2), the diameter of each lesion on DWI was less than 1.5 cm, and 3) more than one vascular territory was involved. Included in the analysis were age, sex, lipoprotein (a) levels, hematocrit, atrial fibrillation (Af), stenosis of middle cerebral artery (MCA), internal carotid artery (ICA) or basilar artery stenosis detected by magnetic resonance angiography (MRA), National Institute of Health Stroke Scale (NIHSS) at admission, and a history of hypertension, diabetes mellitus, hyperlipidemia, and smoking. RESULTS: Twenty-one (24.4%) out of 86 patients with small acute infarctions had multiple acute ischemic lesions. Multiple logistic regression analysis showed that Af and stenosis of ICA or basilar artery were significantly more prevalent in patients with multiple lesions than single lesions. CONCLUSION: Multiple, small lesions visible in DWI are likely to be caused by emboli from heart or atheroma of the large vessels than single small lesion.     

弥散加权成像在超急性期脑梗死诊断中的应用

目的 将磁共振弥散加权成像（DWI）与常规MR技术作对比。评价DWI对超急性期脑梗死诊断的准确性和敏感性。方法 对52例超急性期，急性期，亚急性期，慢性期的患者行DWI，快速自旋回波T2WI，FLAIR及3DTOF法磁共振血管成像检查。对所有病例的病变部位均按神经解剖进行准确定位并与患者的症状，体征相联系。结果 超急性期和急性期脑梗死在DWI图像上表现为高信号，在表观弥散系数（ADC）图上表现为低信号，ADC值低于对侧相应的区域。在超急性期和急性期，病灶的ADC值显著下降,rADC值也明显下降。平均下降约59.12%。而在慢性期ADC值明显升高，甚至较正常组织还高，平均升高达20.3%。结论 DWI对6h症状起病的急性卒中的诊断明显高于传统MRI，DWI可以在超急期发现缺血病灶，早于常规T2WI及FLAR序列图像。DWI对脑梗死的早期诊断及评价起重要的作用。     

Lesion patterns and etiology of ischemia in the anterior inferior cerebellar artery territory involvement: a clinical – diffusion weighted – MRI study

The topography and mechanism of stroke in the anterior inferior cerebellar artery (AICA) territory are delineated before, but the detailed clinical spectrum of lesions involving AICA territory was not studied by diffusion weighted imaging (DWI). We reviewed 1350 patients with posterior circulation ischemic stroke in our registry. We included patients if the diagnosis of AICA territory involvement was confirmed, and DWI, and magnetic resonance angiography were obtained in the 3 days of symptoms onset. The potential feeding arteries of the AICA territory were evaluated on magnetic resonance imaging (MRI) using a three-dimensional rotating cineoangiographic method. There were 23 consecutive patients with lesion involving AICA territory, six with isolated lesion in the AICA territory, six with posterior inferior cerebellar artery, 11 with multiple posterior circulation infarcts (MPCIs). The clinical feature of isolated AICA infarct was vertigo, tinnitus, dysmetria, ataxia, facial weakness, facial sensory deficits, lateral gaze palsy, and sensory-motor deficits in patients with pontine involvement. Patients with largest lesion extending to the anterior and inferolateral cerebellum showed mixed symptomatology of the lateral medullary (Wallenberg's syndrome) and AICA territory involvement. Patients with MPCIs presented various clinical pictures with consciousness disturbances and diverse clinical signs because of involvement of different anatomical structures. Large-artery atherosclerotic disease in the vertebrobasilar system was the main cause of stroke in 12 (52%) patients, cardioembolism (CE) in one (4%), and coexisting large-artery disease and a source of CE in four (17%). The main cause of stroke was atheromatous vertebrobasilar artery disease either in the distal vertebral or proximal basilar artery. The outcome was usually good except those with multiple lesions. The new MRI techniques and clinical correlations allow better definition of the diverse topographical and etiological spectrum of AICA territory involvement and associated infarcts which was previously based on pathological and conventional MRI studies.     

MRI for the management of neonatal cerebral infarctions: importance of timing

PURPOSE: Focal ischemic stroke in neonates is a rare occurrence. Diagnosis with most imaging modalities is difficult, but necessary for initiating an anticoagulatory treatment. The purpose of this study was to evaluate the sensitivity of MRI sequences within the first 14 days of birth. PATIENTS AND METHODS: Four patients with neonatal stroke presenting as seizures were examined using a standard MRI protocol including diffusion-weighted images (DWI) and magnetic resonance angiography (MRA) within 72 h of birth. The time between the onset of symptoms and MRI ranged from 6 h to 48 h. Follow-up examinations were performed on days 5 ( n=1), 7 ( n=2), and 14 ( n=1) for the control of a treatment with low-molecular heparin. RESULTS: Eight infarctions were detected in the four patients, 5 in the middle cerebral artery (MCA), three in the posterior cerebral artery (PCA) territory. All lesions were visible using DWI, four on T2-weighted images. Whereas in two patients small lesions contralateral to a large stroke were missed on T2-weighted images, the diagnosis would have been missed altogether without DWI in one patient. On follow-up, the visibility of the infarctions had declined using DWI after 5 days and the lesions were invisible after 1 week. Fourteen days after the stroke, an increased diffusion was detected in the infarcted brain tissue. By this time, all lesions were visible on T2-weighted images. CONCLUSION: In neonates, infarcted brain tissue can be detected using DWI with high sensitivity during the first 2 days after stroke and before other sequences are diagnostic. However, the diffusion restriction does not persist beyond 1 week. After 5 days, diagnosis has to rest mainly on T2-weighted images.