磁共振弥散加权成像对超急性期脑梗死的诊断价值

目的 研究磁共振弥散加权成像(DWI)在超急性期脑梗死诊断中的价值.方法 对51例脑梗死患者超急性期头颅核磁共振常规T1WI、T2WI序列与DWI序列的扫描结果进行比较.结果 51例脑梗死患者在临床症状出现后6h内,6例在T2WI序列上有长T2改变,48例DWI序列显示高信号,2者的阳性率有显著性差异(X2=18.01,P<0.01).结论 DWI对超急性期脑梗死的诊断准确、可靠,具有良好的临床应用价值.     

磁共振弥散加权像诊断急性脑梗死临床分析

目的探讨磁共振弥散加权像(DWI)在急性脑梗死诊断中的价值,确定DWI对超急性脑梗死诊断的敏感性和特异性。方法对60例急性脑梗死患者,经CT检查排除脑出血,均应用1.5T超导MR成像设备行DWI和常规MRI扫描。结果60例均证实为脑梗死。(1)13例超急性期(发病后6h以内),其中2~3h3例;常规MRI:T1WI无异常信号,T2WI1例无异常改变。DWI已显示明显高信号。(2)急性期(发病后6~72h)33例,T1WI26例略低信号,T2WI高信号,33例DWI均为高信号。(3)14例亚急性期(发病后4~10d),T1WI均为低信号,T2WI、DWI均为高信号。结论DWI在急性期脑梗死,尤其是超急性期脑梗死(发病6h以内),诊断方面明显优于常规MRI扫描,DWI诊断脑梗死及超急性脑梗死的敏感性和特异性均为100%,从而为科学地指导临床行超早期溶栓治疗,并为临床治疗效果提供评价指标。     

不典型脑干梗死的临床及磁共振弥散加权成像表现

目的 探讨不典型脑干梗死的临床及磁共振弥散加权成像(DWI)表现.方法 分析50例经头颅DWI检查证实脑干为责任病灶的急性不典型脑梗死的临床及DWI表现.结果 50例脑干梗死患者均不具有脑干病变典型的交叉征表现,只有10例在头颅CT脑干处见低密度影,有28例在T2WI及FLAIR序列上脑干处显示为高信号,所有病例的DWI均显示脑干处高信号或略高信号.结论 越来越多的脑干梗死缺乏其典型的临床表现,尤其在反复多发脑梗死病例中,通过DWI可明确脑干为责任病灶,在急性不典型脑干梗死显示能力上优于常规序列,对临床治疗及预后判断有十分重要的意义.     

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.     

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。     

Wernicke脑病的MRI诊断与临床

目的探讨Wernicke脑病(WE)的MRI特征及其诊断价值。方法回顾性分析20例经临床证实的WE患者的临床及MRI检查资料。结果 WE的MRI特征主要表现为对称性T1WI低信号、T2WI高信号,在FLAIR序列中呈明显高信号,在DWI上呈明显高信号,ADC上呈低信号。主要累及部位为乳头体,第三、四脑室及中脑导水管周围灰质。结论WE早期缺乏特征性临床表现,但具有典型的MRI表现,头颅MRI检查对于该病的早期诊断具有重要的临床价值。     

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。     

早期脑梗死的临床与磁共振弥散加权成像

目的 从临床角度探讨磁共振弥散加权成像（diffusion weighted imagine,DWI)对早期脑梗死的诊断价值和确定DWI在区分常规MRI上所示的多发梗死灶中急性梗死方面的能力。方法 60例脑梗死均进行MRI常规程序及DWI（程度检查,并由4位经验丰富的医师在不了解患者临床体征的情况下进行阅片、记录出病变所在的详细的神经解剖部位,对同一层面所有的磁共振像进行比较,重点分析信号强度的病灶大小。数据经统计学分析。结果 DWI对超急性合肥市急性期脑梗死可显示T2加权像不能显示的病灶,并随时间延长显影范围逐渐增大,在T2加权像上可显示的病灶中,DWI可更清楚、更全面地显示病灶,大于T2病灶。在急性后期,常规MRI及DWI均有较清晰的影像学改变,恢复期及慢性期,DWI影像学逐渐改变变成等信号、杂信号,部分为囊性信号,且不易显示病灶。结论 DWI能非常可靠地显示超急性及急性脑梗死,而在急性后期及慢性期不如T2WI。其具有区分急性和非急性脑梗死的能力。     

桥脑梗死患者临床及影像学特点

目的分析经磁共振成像(MRI)证实的15例桥脑梗死患者的临床及影像学特点。方法通过对15例桥脑梗死患者进行常规MRI和弥散加权成像(DWI)扫描,比较同一层面的所有磁共振图像,分析其临床表现及影像学特点。结果除1例急性桥脑梗死患者的临床表现符合经典定位理论外,其余大部分桥脑梗死患者均以一侧中枢性面、舌瘫,肢体偏瘫为主要临床表现。15例患者经MRI和DWI扫描,均可发现梗死灶,其中1例为发病3 h内的超急性期患者,DWI可见病灶显影,T_2WI未见异常。随着时间的推移,DWI逐渐变为等信号和低信号。结论大部分桥脑梗死患者的临床表现与幕上大脑半球基底核区的梗死相似。DWI可以显示超急性期桥脑梗死病灶,DWI结合T_2WI有助于多次脑梗死患者责任病灶的确定。     

DWI和MRA在超急性期脑梗死中的临床应用

目的探讨磁共振弥散加权成像(DWI)和血管成像(MRA)在超急性期脑梗死中的临床应用价值。方法回顾性分析48例超急性期脑梗死患者的临床和磁共振资料,全部患者均行CT、常规MRI、DWI和MRA检查。结果 48例超急性期脑梗死的CT、常规T2WI、FLAIR及DWI阳性率分别为0、16.7%、37.5%和100%,MRA显示靶血管正常4例,动脉硬化36例,狭窄16例,闭塞8例。结论 DWI联合MRA能够准确显示责任病灶及靶血管受累情况,为超急性期脑梗死早期溶栓治疗提供切实可行的影像学依据。     

Denervation study of synapses of organ of corti of old world monkeys

Fine structural characteristics of synapses in the spiral organ of Corti were examined, with reference to differences between inner and outer haircell systems, and to location of neurons of origin of efferent axons. Surgical interruption of crossed olivocochlear bundle, of vestibular nerve, of facial nerve, and excision of superior cervical ganglia were used to determine the pathways of efferent axons. Interruption of the vestibular nerve near the brainstem results in degeneration of all efferent terminals on outer hair cells. Mid-line lesions at, and caudal to, the facial colliculus result in degeneration of about half of these efferent terminals. Efferent synaptic bulbs to the inner hair-cell system are small, of the order of one micron, and form type 2 junctions with afferent dendrites. They tend to have more large dense-core vesicles (about 80 nm) than the large efferent terminals of the outer hair-cell system, and appear to be the terminals of axons in the habenula perforata, which exhibit varicosities laden with large dense core vesicles. The varicosities are unaffected by excision of the superior cervical ganglia. So far as our material can reveal, it appears that the varicosities in the habenula perforata do not survive vestibular root interruption, nor do the efferent processes in the internal spiral bundle or at the base of inner hair cells. Most interestingly, the afferent processes of the inner hair-cell system, as identified for example by their relation to pre-synaptic bodies in the inner hair cells, are subject to a trans-synaptic reaction after severance of the vestibular root. They undergo a dramatic cytological transformation, characterized by increase of volume, engorgement with microtubules, microfilaments, microvesicles of various sizes, and clusters of lysosomes. Thus, both the efferent and afferent terminals of the inner hair-cell system show marked cytological differences from the corresponding terminals of the outer hair cell system.     

Mechanism of action of tubocurarine on nicotinic cholinoreceptors of neurons of the sympathetic ganglia of rats

Tubocurarine (Tc) effect on membrane currents elicited by acetylcholine (ACh) was studied in isolated superior cervical ganglion neurons of rat using patch-clamp method in the whole-cell recording mode. The "use-dependent" block of ACh current by Tc was revealed in the experiments with ACh applications, indicating that Tc blocked the channels opened by ACh. Mean lifetime of Tc-open channel complex, tau, was found to be 9.8 +/- 0.5 s (n = 7) at -50 mV and 20-24 degrees C. tau exponentially increased with membrane hyperpolarization (e-fold change in tau corresponded to the membrane potential shift by 61 mV). Inhibition of the ACh-induced current by Tc (3-30 microM/1) was completely abolished by membrane depolarization to the level of 80-100 mV. Inhibition of ACh-induced current was augmented at increased ACh doses. It is concluded that the open channel block produced by Tc is likely to be the only mechanism for Tc action on nicotinic acetylcholine receptors in superior cervical ganglion neurons of rat.     

The effect of age of onset of PD on risk of dementia

Background Dementia occurs in the majority of patients with Parkinson’s disease (PD). Late onset of PD has been reported to be associated with a higher risk for dementia. However, age at onset (AAO) and age at baseline assessment are often correlated. The aim of this study was to explore whether AAO of PD symptoms is a risk factor for dementia independent of the general effect of age. Methods Two community-based studies of PD in New York (n = 281) and Rogaland county, Norway (n = 227) and two population-based groups of healthy elderly from New York (n = 180) and Odense, Denmark (n = 2414) were followed prospectively for 3–4 years and assessed for dementia according to DSM-IIIR. All PD and control cases underwent neurological examination and were followed with neurological and neuropsychological assessments. We used Cox proportional hazards regression based on three different time scales to explore the effect of AAO of PD on risk of dementia, adjusting for age at baseline and other demographic and clinical variables. Findings In both PD groups and in the pooled analyses, there was a significant effect of age at baseline assessment on the time to develop dementia, but there was no effect of AAO independent of age itself. Consistent with these results, there was no increased relative effect of age on the time to develop dementia in PD cases compared with controls. Interpretation This study shows that it is the general effect of age, rather than AAO that is associated with incident dementia in subjects with PD. Received in revised form: 22 December 2005     

Limits of deinstitutionalization--perspectives of relatives of psychiatric patients

After a hopeful beginning, the social process of the reintegration of those with severe mental illness has come to a standstill. I am led to wonder whether "the community" really wants to live together with people suffering from severe mental illness, and if so, how closely? As long as the medical treatment of mental illness provided by the general practitioners is fundamentally deficient, as they are not able to prescribe the necessary interventions--such as out-patient psychiatric nursing, and service providers in the out-patient sector are content with offering increasingly intensive forms of care for the less seriously ill at the cost of the Social Welfare System--the reintegration of those with serious mental illness remains an illusion--which is mainly to the benefit of providers of residential care in homes and hostels.