神经白塞病的影像学特点和动态变化

目的总结神经白塞病在不同序列MRI检查上病灶的好发部位和特点。方法回顾性分析7例神经白塞病患者的MRI检查资料。MRI检查序列包括:T1WI、T2WI、核磁共振弥散加权成像、表观弥散系数和核磁共振波谱。结果 7例神经白塞病患者均表现为脑实质损害。最常见的神经系统症状包括癫痫发作、头痛、躯体感觉和运动障碍、延髓麻痹、精神障碍、认知障碍和锥体束征。MRI检查常见受累部位包括脑干、内囊、皮质下白质和基底节。病灶在MRI上表现为T1WI为等信号或低信号,T2WI为高信号,其中3例可见异常强化。2例神经白塞病患者表现为核磁共振弥散加权成像稍高信号,表观弥散系数信号轻度升高,核磁共振波谱未见明显异常代谢区。3例患者在首次MRI检查后15d～5个月进行随访发现原发病灶均减少或消失,但可出现新发病灶。结论神经白塞病是白塞病最严重的并发症之一,MRI检查是诊断神经白塞病非常敏感的方法,神经白塞病以脑实质损害为主,不同序列的MRI检查具有特征性改变。     

磁共振技术在细菌性脑脓肿诊疗中的应用

近年来,磁共振(MRI)对细菌性脑脓肿的诊断和治疗提供了可靠的影像学依据,尤其对脑脓肿与脑肿瘤坏死囊变的鉴别诊断极有意义。这些技术包括弥散加权成像(DWI)和表观弥散系数(ADC)、灌注加权成像(PWI)、质子MRI波谱(1H-MRS)。1MRI常规扫描脑脓肿MRI表现与其各发展阶段的病理改变密切相关。急性化脓性脑炎或脑膜脑炎期,病灶小血管发生脓毒性炎症,脑组织坏死软化,出现若干小液化区,灶周血管扩张伴炎症细胞浸润和水肿,MRI呈T1WI低信号、T2WI高信号,边界不清,与周边水肿融为一体;增强后病灶呈不规则强化,可伴脑膜线状强化;化脓期液…     

后颅窝原发性中枢神经系统淋巴瘤MRI多模态表现

目的总结后颅窝原发性中枢神经系统淋巴瘤(PCNSL)MRI多模态表现,提高对后颅窝PCNSL诊断的正确率。方法回顾性分析经病理证实的15例后颅窝PCNSL的MRI多模态影像学表现,包括MRI平扫和增强、弥散加权成像(DWI)和磁共振波谱成像(MRS)。结果 15例PCNSL多发病灶者5例,单发病灶者10例均位于幕下。后颅窝病灶位于小脑半球和小脑蚓部、中脑、第四脑室、桥小脑角区等。T1WI上呈稍低或中等信号,T2WI上呈中等或稍高信号。所有病灶表现为明显强化,6个病灶呈现"尖角征"和"脐凹征"。后颅窝20个病灶中结节状强化12个,条纹状强化4个,斑片状强化3个,四脑室团块状不均匀强化1个。5例DWI呈均质高信号,2例DWI为不均匀高信号,3例DWI为中等信号;ADC呈低至等信号。后颅窝PCNSL的ADC值为(0.62±0.095)×10~(-3) mm~2/s,与对侧脑实质ADC值比较有显著差异(P0.05)。3例于MRS出现宽大耸立的Lip峰,2例Lip峰短小。结论后颅窝PCNSL的MRI多模态表现具有一定的特征性,但对于不典型的后颅窝PCNSL术前诊断仍非常困难。     

毛细胞黏液样型星形细胞瘤的MRI、CT诊断

目的 探讨毛细胞黏液样型星形细胞瘤(PMA)的MRI、CT表现.方法 回顾性分析首都医科大学附属北京天坛医院神经放射科2010年11月至2014年8月间经手术病理证实的39例PMA患者的MRI、CT表现,其中男19例,女20例,年龄为10个月至47岁.结果 下丘脑/视交叉区PMA 25例,中位发病年龄为5.83岁,病灶最大径平均47.44 mm,无明显瘤周水肿,有不同程度的脑积水(P ＜0.05);14例MRI检查T2WI高信号中见条状低信号影,22例增强后实性成分呈病灶内多环状强化;3例磁共振扩散加权成像(DWI)检查均表现为弥散不受限,其中9例表现为蛛网膜下腔播散(P ＜0.05);CT检查钙化6例,出血1例.非下丘脑/视交叉区PMA 14例,中位发病年龄为17岁,病灶最大径平均39.43 mm;6例轻度瘤周水肿,3例轻度脑积水;6例T2WI高信号中见条状低信号影,11例增强后病灶明显强化,强化方式为囊性病灶内附壁结节“星芒状”强化;DWI检查1例示弥散不受限,未发现蛛网膜下腔播散;磁共振波谱(MRS)检查3例,病灶实性成分符合一般神经胶质瘤的MRS谱线;CT检查钙化2例,出血2例.结论 PMA可发生在颅内各部位,MRI表现为囊实性肿块,实性成分强化明显,下丘脑/视交叉区发病年龄较小,蛛网膜下腔播散常见;非下丘脑/视交叉区发病年龄较大,增强后附壁结节“星芒状”强化较具特征性.     

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。     

神经元核内包涵体病的多模态MRI影像特征

目的 探讨神经元核内包涵体病(NIID)的多模态MRI影像学特征。方法 回顾性分析14例经病理证实的NIID患者的临床及影像学资料。结果 本组14例中12例伴有不同部位的脑萎缩。13例头颅MRI T₂WI检查示对称性脑白质高信号，3例左侧颞、顶、枕叶皮质病变。12例DWI序列可见皮髓质交界处“飘带样”、“火焰样”高信号。8例增强后未见明显强化，1例急性发作期出现皮质及脑膜明显强化。2例行动脉自旋标记(ASL)成像检查示病变呈高灌注，1例呈稍低灌注。2例进行磁共振波谱(MRS)检查示神经元损伤。2例行磁敏感加权成像(SWI)未见明显含铁血黄素沉积。1例DTI示全脑广泛白质纤维减少。结论 NIID影像学表现具有皮髓质交界处“飘带样”异常信号等特征，多模态MRI检查如ASL、MRS、SWI、DTI更加有助于NIID的诊断及病情严重程度的判断。     

原发性中枢神经系统血管炎的临床、影像及病理学特点

目的探讨原发性中枢神经系统血管炎(PACNS)的临床、影像及病理学特点。方法回顾性分析8例PACNS患者(4例临床拟诊,4例确诊)的临床资料。结果本组男5例,女3例;平均年龄32岁;平均病程11个月。首发症状头痛5例,肢体无力2例,言语不清1例。临床表现头痛8例,肢体无力麻木5例,言语障碍1例,癫癎样发作2例;7例呈缓慢进展病程,1例呈复发、缓解、缓慢进展病程。8例磁共振成像(MRI)均有异常,其中单侧病灶6例,双侧病灶2例;病灶位于脑叶7例,病灶边缘欠清晰、不规则或非典型楔形,同时累及皮质和皮质下,1例病灶位于左额顶部扣带回区,呈大片长条形,病变区外缘呈尖角或指状;病灶均有不同程度的强化,7例沿脑沟脑回强化,1例呈"肿块样"成堆不规则线条状强化;5例弥散加权成像(DWI)呈高信号,表现扩散系数(ADC)为低信号;8例磁共振血管成像(MRA)检查,表现为血管僵硬,血管边缘毛糙不清,管壁欠光滑,节段性狭窄、扩张,末段分支减少;4例全脑数字减影血管造影(DSA)检查,可见脑内动脉中末端呈节段性狭窄、扩张、分支减少。4例脑组织活检,病理结果示以淋巴细胞浸润为主的血管炎。5例行糖皮质激素、3例行环磷酰胺治疗,预后均良...     

72例脑脓肿的临床分析

目的 探讨脑脓肿的临床特点、诊断和治疗方法.方法 回顾性分析72例脑脓肿病人的临床资料,72例病人行头部CT和常规MRI平扫+增强检查,其中46例行磁共振弥散加权成像(DWI)检查,7例行磁共振波谱(MRS)检查.手术切除43例,MRI导航定向穿刺引流17例,保守治疗12例.结果 随访3个月～4年,治愈65例,GOS评分:5分60例,4分4例,3分1例.死亡7例.结论 常规头部CT及MRI检查结合DWI和MRS等有利于脑脓肿的诊断和鉴别诊断,综合评估、及时正确的治疗对脑脓肿病人的预后至关重要.     

MELAS型线粒体脑肌病的MRI诊断

目的探讨合并乳酸血症和卒中样发作的线粒体脑肌病（MELAS）的磁共振成像（MRI）影像学特点。方法收集经临床病理证实的MELAS型线粒体脑肌病共6例,回顾性分析其MRI和磁共振波谱（MRS）资料。结果脑MRI检查,MELAS表现为大脑半球各叶大小不等片状病灶;病变位于脑皮质区,病灶的分布与脑血供分布不一致;自旋回波T1加权像呈低信号、T2加权像呈高信号;扩散加权成像（DWI）呈高信号。MRS分析显示病灶区见典型的乳酸盐峰,N-乙酰天门冬氨酸盐,肌酸值正常或略降低。扩散张量成像（DTI）显示病灶区脑皮质下白质纤维束破坏、中断、稀少。结论MELAS型线粒体脑肌病的病变形态、分布具有特征性,常规MRI与DWI、DTI及MRS等磁共振技术,对MELAS的定性诊断具有很高的价值。     

表现为后循环缺血性病变的小脑幕硬脑膜动静脉瘘的临床和影像学特点(附3例报告)

目的 探讨表现为后循环缺血性病变的小脑幕硬脑膜动静脉瘘(DAVF)的临床和影像学特点.方法 回顾性分析3例表现为后循环缺血性病变的小脑幕DAVF患者的临床和影像学资料.结果 本组患者起病形式多样,均表现头晕、恶心、呕吐,病变侧共济失调、水平眼震;1例患者出现交叉性感觉障碍、轻度延髓麻痹和不完全Horner征;头颅MRI均示小脑病变,其中1例合并延髓病变,病灶处均出现长T1、长T2及弥散加权成像高信号;2例MRI增强见小脑病灶强化及多条弯曲血管影;3例头部数字减影血管造影(DSA)检查均发现小脑幕DAVF瘘口.结论 小脑幕DAVF可引起小脑及脑干缺血表现,MRI增强扫描可见病灶强化及异常血管影,DSA检查可明确诊断.     

弥散成像和血流灌注成像磁共振诊断急性缺血性脑血管病的意义

目的评价弥散成像（DWI）、血流灌注成像（PWI）磁共振对急性缺血性脑血管病的诊断价值。方法用DWI、PWI诊断急性脑缺血,并与常规MRI结果比较。结果经MRI检查证实的急性缺血性脑血管病患者共22例。其中发病后90分钟至6小时检查者11例,其CT及常规MRI未见异常,3例短暂性脑缺血发作（TIA）患者的DWI、PWI正常;其余8例脑梗死患者经DWI、PWI检查,均发现相对应的病灶,且6例灌注减低体积（PWIv）＞弥散异常体积（DWIv）,2例PWIv＝DWIv。起病在6－12小时5例,4例行PWI检查,3例PWIv＞DWIv,1例PWIv＝DWIv。起病在12－48小时6例,2例行PWI检查,PWIv＝DWIv。8例陈旧病灶在DWI上表现为低信号,所有新病灶在DWI上均为高信号。结论DWI、PWI可超早期诊断脑梗死,并可帮助了解缺血半暗带。T2加权像和DWI结合可以鉴别新旧梗死灶。     

颅内原发性淋巴瘤DWI及PWI表现

目的 探讨颅内原发性淋巴瘤扩散加权成像(DWI)和灌注加权成像(PWI)特点.方法 回顾性分析10例颅内原发性淋巴瘤的DWI表现和9例颅内原发性淋巴瘤的PWI特征,所有病例均经病理证实,并结合其病理特征与高级别(Ⅲ、Ⅳ级)星形细胞瘤作对照.结果 颅内原发性淋巴瘤DWI多呈均匀高信号,肿瘤实质ADC值为(79.73±10.21)×10-5mm2/s,明显低于高级别星形细胞瘤ADC值(99.81±19.57)×10-5mm2/s(P=0.002).9例行PWI检查,颅内原发性淋巴瘤肿瘤实质最大rCBV比值为1.71±0.59,而14例高级别星形细胞瘤肿瘤实质最大rCBV比值为5.17±1.73,与高级别旱形细胞瘤比较,颅内原发性淋巴瘤呈低灌注趋势(P=0.001).结论 颅内原发性淋巴瘤DWI、PWI具有一定的特征,术前行DWI、PWI有助于提高MRI对颅内原发性淋巴瘤的诊断水平.     

MR灌注与弥散加权成像不同匹配与急性脑梗死降纤治疗效果的关系

目的 探讨MR灌注加权成像(PWI)与弥散加权成像(DWI)(PWI/DWI)不同匹配与急性脑梗死降纤治疗效果的关系.方法 给38例急性脑梗死患者行巴曲酶降纤治疗,在治疗前予以MR PWI及DWI检查,在治疗前和治疗后进行美国国立卫生研究院卒中量表(NIHSS)评分并评定疗效.比较PWI/DWI不同匹配患者治疗前后的N...     

Etiology of Perfusion-Diffusion Magnetic Resonance Imaging Mismatch Patterns

BACKGROUND AND PURPOSE: Diffusion-and perfusion-weighted magnetic resonance imaging (DWI and PWI) are useful tools for the assessment of brain ischemia. Discrepancies between the extent of DWI and PWI abnormalities are thought to depend pre dominantly on time from symptom onset to magnetic resonance imaging (MRI) examination. However, underlying ischemic stroke etiology can also be important. A mismatch may indicate the presence of tissue at risk for infarction, whereas the relevance of other DWI/PWI patterns is uncertain. The authors therefore investigated the etiology of brain ischemia in patients with different DWI/PWI patterns. METHODS: Retrospective study of 130 patients with acute brain ischemia and detailed stroke workup, including MRI within a week after symptom onset (40 +/- 39 hours). Patients were divided into the following groups: mis-match (PWI > DWI), reverse mismatch (DWI > PWI), and match (<25% difference between PWI and DWI). RESULTS: Mismatch occurred in 49% of patients, whereas 22% had reverse mis-match and 29% matched lesions. Time from symptom onset to MRI examination was similar between the 3 groups. Largeartery atherosclerosis increased by almost 4-fold the odds of mismatch (odds ratio: 3.89, 95% confidence interval: 1.72-8.78; P < .001), whereas patients with reverse mismatch were likely to have cryptogenic stroke. Patients with matched lesions were similarly distributed among different stroke subtypes. CONCLUSIONS: Ischemic stroke etiology appears to influence the development of specific DWI/PWI patterns. Prospective studies are needed to confirm these observations.     

磁共振弥散加权成像对急性脑梗死的诊断价值

目的:探讨磁共振弥散加权成像(DWI)对急性脑梗死的诊断价值.方法:对26例急性脑梗死患者(发病＜6h4例、6-24h14例、1-7d8例)进行常规MRI(T,flair,T2WI,T2flair)检查以及DWI检查,并由计算机算出表观扩散系数(ADC)图.结果:发病＜6h的4例患者常规MRI未见异常;DWI均出现高信号;ADC均为低信号.发病6h-7d的22例患者MRI T2 WI均为高/稍高信号,T1 flair均为低/稍低信号;DWI均为高信号;ADC均为低信号.结论:DWI能在超早期显示急性脑梗死的病灶,对急性脑梗死有着非常重要的诊断价值.     

Early motor evoked potentials in acute stroke: adjunctive measure to MRI for assessment of prognosis in acute stroke within 6 hours

BACKGROUND: In acute stroke, a magnetic resonance (MR) perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) mismatch (PWI>DWI mismatch) may indicate tissue at risk for infarction and poor prognosis. However, different to early enthusiasm about this surrogate marker, its validity has shown several drawbacks in individual patients. Rather than relying on imaging, we evaluated motor evoked potentials (MEP) as a measure of cerebral function in the acute stroke setting. METHODS: Thirteen patients with acute hemiparetic stroke underwent time to peak PWI and DWI within 6 h after onset as well as recordings of early MEP of first dorsal interosseous muscles. Outcome was assessed by the Unified Neurological Stroke Scale and Barthel Index at day 42. RESULTS: Of 8 patients with PWI>DWI mismatch, 4 patients with normal MEP had a good clinical outcome and 4 patients with absent or pathological MEP had an unfavourable outcome (p < 0.05, Fisher's exact test). In all patients without PWI>DWI mismatch, MEP findings predicted clinical outcome. Normal MEP at day 0--but not PWI/DWI findings--significantly correlated with a good clinical outcome. CONCLUSIONS: Early MEP recordings in acute stroke patients provide valid prognostic information; they may become more useful for specific treatment decisions than presently available MRI surrogate parameters.     

Multimodal imaging in diagnosis of Alzheimer's disease and amnestic mild cognitive impairment: value of magnetic resonance spectroscopy, perfusion, and diffusion tensor imaging of the posterior cingulate region

The purpose of this study was to assess metabolic, perfusion, and microstructural changes within the posterior cingulate area in patients with Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI) using advanced MR techniques such as: spectroscopy (MRS), perfusion weighted imaging (PWI), and diffusion tensor imaging (DTI). Thirty patients with AD (mean age 71.5 y, MMSE 18), 23 with aMCI (mean age 66 y, MMSE 27.4), and 15 age-matched normal controls (mean age 69 y, MMSE 29.5) underwent conventional MRI followed by MRS, PWI, and DTI on 1.5 Tesla MR unit. Several metabolite ratios (N-acetylaspartate [NAA]/creatine [Cr], choline [Ch]/Cr, myoinositol [mI]/Cr, mI/NAA, mI/Cho) as well as parameters of cerebral blood volume relative to cerebellum and fractional anisotropy were obtained in the posterior cingulate region. The above parameters were correlated with the results of neuropsychological tests. AD patients showed significant abnormalities in all evaluated parameters while subjects with aMCI showed only perfusion and diffusion changes in the posterior cingulate area. Only PWI and DTI measurements revealed significant differences among the three evaluated subject groups. DTI, PWI, and MRS results showed significant correlations with neuropsychological tests. DTI changes correlated with both PWI and MRS abnormalities. Of neuroimaging methods, DTI revealed the highest accuracy in diagnosis of AD and aMCI (0.95, 0.79) followed by PWI (0.87, 0.67) and MRS (0.82, 0.47), respectively. In conclusion, AD is a complex pathology regarding both grey and white matter. DTI seems to be the most useful imaging modality to distinguish between AD, aMCI, and control group, followed by PWI and MRS.     

急性脑梗死缺血半暗带演变的磁共振成像研究

目的：探讨应用磁共振弥散／灌注成像技术判断急性脑梗死后缺血半暗带IP存在的范围和时间规律。方法：对72例发病时间在1～24h的急性脑梗死患者行常规MRI、磁共振弥散加权成像（DWI）和磁共振灌注加权成像（PWI）确定IP的范围，计算梗死中心区、IP区及对侧镜像区的ADC值和rADC值并加以比较。结果：26例发病时间〈6h的患者PWI显示存在低灌注区者，其中PWI〉DWI者21例，30例发病时间在6～24h的患者PWI显示存在低灌注区者，其中PWI〉DWI者2例；PWI〉DWI者病灶中心ADC值与IP区及对侧镜像区ADC值差异有统计学意义，其IP区ADC值与其对侧镜像区差异无统计学意义。结论：DWI和PWI结合能灵敏的判断IP的存在，IP存在的时间窗有一定的个体差异。     

Cerebrovascular diseases

Conventional neuroradiological techniques, such as computed tomography (CT) and magnetic resonance imaging (MRI), make a fundamental contribution in both the acute and chronic phases of stroke. Recent years have witnessed the development of new imaging modalities, which include diffusion-weighted imaging (DWI), perfusion-weighted imaging (PWI), CT-angiography (CTA), MR-angiography (MRA), magnetic resonance spectroscopy (MRS), diffusion tensor imaging (DTI) and functional MRI (fMRI). While CTA, MRA, DWI and PWI are commonly used for clinical purposes, DTI, MRS and fMRI are becoming increasingly important in the field of experimental research of cerebrovascular diseases, but are still far from becoming of primary usefulness in the everyday clinical setting.