基于DTI评价急性缺血性脑卒中运动功能缺损程度与肾虚髓亏证的相关性研究＊

目的 运用核磁共振弥散张量成像技术（DTI），从皮质脊髓束损伤程度评价的角度，探讨肾虚髓亏证与急性缺血性脑卒中运动功能缺损程度相关性，丰富中风病病机及证候诊断，拓宽缺血性脑卒中的中医药防治思路，为急性缺血性脑卒中肾虚髓亏证患者运动功能损伤程度提供临床依据，强调肾虚髓亏证在急性缺血性脑卒中运动功能损伤中的重要意义。方法 纳入符合诊断标准的90例病例，根据证候分别归入肾虚髓亏组和非肾虚髓亏组，每组各45例。每组患者均给予常规西药治疗。对两组患者入院后行弥散张量成像检测，同时分别于治疗前及治疗后14天，记录两组患者NIHSS评分、改良Barthel指数量表及简化Fugl-Meyer运动功能评分量表评分，比较两组病例发病时的轻重程度及治疗前后两组病例组间的恢复差异。结果 研究显示，治疗前肾虚髓亏组在NIHSS评分方面高于非肾虚髓亏组（P<0.05）；治疗前肾虚髓亏组在改良Barthel指数量表及简化Fugl-Meyer运动功能评分方面低于非肾虚髓亏组（P<0.05）。治疗前后NIHSS评分、改良Barthel指数评分及简化Fugl-Meyer运动功能评分改善情况，非肾虚髓亏组要优于肾虚髓亏组（P<0.05）。治疗前两组患者在健侧内囊后肢及大脑脚外侧处FA值及ADC值无明显差异；肾虚髓亏组在患侧内囊后肢及大脑脚外侧处FA值及ADC值均低于非肾虚髓亏组（P<0.05）。相关性分析得出，两组患者患侧内囊后肢FA值与患者治疗前NIHSS评分呈负相关；两组患者患侧内囊后肢FA值与患者改良Barthel指数评分及简化Fugl-Meyer运动功能评分呈正相关；肾虚髓亏组患者患侧内囊后肢FA值与肾虚髓亏证中医证候评分呈负相关。结论 肾虚髓亏是急性缺血性脑卒中运动功能障碍的重要病机。研究结果显示，两组皮质脊髓束损伤程度与神经功能及运动功能损伤存在相关性，且肾虚髓亏组在皮质脊髓束的损伤程度方面与其中医证候评分呈负相关。     

弥散张量成像在癫痫中的研究进展

癫痫作为多种病因引起的神经系统慢性、发作性疾病,严重影响着患者的生活质量,因此对其及时诊断和早期治疗极为重要。目前已有多种神经影像技术用于癫痫的定位、定侧和病理生理研究。弥散张量成像是利用水分子在组织中弥散的各向异性成像的磁共振技术,是目前唯一能在活体中无创性地显示脑白质纤维束的方法,它能敏感地显示脑部细微结构,并能揭示各个结构间的功能联系,有助于癫痫的研究。本文主要从癫痫的病因诊断、癫痫手术的辅助指导、癫痫的结构网络及其与癫病功能障碍的相关性研究等方面对DTI应用于癫痫的最新研究进展进行综述。     

Motion‐compensated b‐tensor encoding for in vivo cardiac diffusion‐weighted imaging

Motion is a major confound in diffusion‐weighted imaging (DWI) in the body, and it is a common cause of image artefacts. The effects are particularly severe in cardiac applications, due to the nonrigid cyclical deformation of the myocardium. Spin echo‐based DWI commonly employs gradient moment‐nulling techniques to desensitise the acquisition to velocity and acceleration, ie, nulling gradient moments up to the 2nd order (M2‐nulled). However, current M2‐nulled DWI scans are limited to encode diffusion along a single direction at a time. We propose a method for designing b‐tensors of arbitrary shapes, including planar, spherical, prolate and oblate tensors, while nulling gradient moments up to the 2nd order and beyond. The design strategy comprises initialising the diffusion encoding gradients in two encoding blocks about the refocusing pulse, followed by appropriate scaling and rotation, which further enables nulling undesired effects of concomitant gradients. Proof‐of‐concept assessment of in vivo mean diffusivity (MD) was performed using linear and spherical tensor encoding (LTE and STE, respectively) in the hearts of five healthy volunteers. The results of the M2‐nulled STE showed that (a) the sequence was robust to cardiac motion, and (b) MD was higher than that acquired using standard M2‐nulled LTE, where diffusion‐weighting was applied in three orthogonal directions, which may be attributed to the presence of restricted diffusion and microscopic diffusion anisotropy. Provided adequate signal‐to‐noise ratio, STE could significantly shorten estimation of MD compared with the conventional LTE approach. Importantly, our theoretical analysis and the proposed gradient waveform design may be useful in microstructure imaging beyond diffusion tensor imaging where the effects of motion must be suppressed.     

Sensory evoked potentials in patients with Rett syndrome through the lens of animal studies: Systematic review

ObjectiveSystematically review the abnormalities in event related potential (ERP) recorded in Rett Syndrome (RTT) patients and animals in search of translational biomarkers of deficits related to the particular neurophysiological processes of known genetic origin (MECP2 mutations).MethodsPubmed, ISI Web of Knowledge and BIORXIV were searched for the relevant articles according to PRISMA standards.ResultsERP components are generally delayed across all sensory modalities both in RTT patients and its animal model, while findings on ERPs amplitude strongly depend on stimulus properties and presentation rate. Studies on RTT animal models uncovered the abnormalities in the excitatory and inhibitory transmission as critical mechanisms underlying the ERPs changes, but showed that even similar ERP alterations in auditory and visual domains have a diverse neural basis. A range of novel approaches has been developed in animal studies bringing along the meaningful neurophysiological interpretation of ERP measures in RTT patients.ConclusionsWhile there is a clear evidence for sensory ERPs abnormalities in RTT, to further advance the field there is a need in a large-scale ERP studies with the functionally-relevant experimental paradigms.SignificanceThe review provides insights into domain-specific neural basis of the ERP abnormalities and promotes clinical application of the ERP measures as the non-invasive functional biomarkers of RTT pathophysiology.     

Influence of SENSE on image properties in high-resolution single-shot echo-planar DTI.

Limited spatial resolution is a key obstacle to the study of brain white matter structure with diffusion tensor imaging (DTI). In its frequent implementation with single-excitation spin-echo echo-planar sequences, DTI's ability to resolve small structures is strongly restricted by T2 and T2* decay, B0 inhomogeneity, and limited signal-to-noise ratio (SNR). In this work the influence of sensitivity encoding (SENSE) on diffusion-weighted (DW) image properties is investigated. Computer simulations showed that the PSF becomes narrower with increasing SENSE reduction factors, R, enhancing the intrinsic resolution. After a brief theoretical discussion, we describe the estimation of SNR on a pixel-by-pixel basis as a function of R. The mean image SNR behavior is manifold: SENSE is capable of increasing SNR efficiency by reducing the echo time (TE). Each SNR(R) curve reveals a maximum that depends on the amount of partial Fourier encoding used. The overall best SNR efficiency for an eight-element head coil array and a b-factor of 1000 s/mm2 is achieved at R = 2.1 and partial Fourier encoding of 60%. In vivo tensor maps of volunteers and a patient, with an in-plane resolution of 0.78 x 0.78 mm2, are also presented to demonstrate the practical implementation of the parallel approach.     

脂肪族聚酯与高氯酸锂络合物的结构与导电性

本文通过酯交换反应合成了一系列脂肪族聚丁二酸酯,对他们的结构和性能作了表征。发现聚酯存在多晶现象,其熔点有奇偶性变化规律。探索了由此系列聚酯与高氯酸锂形成的固体电解质的结构和离子导电性。无机盐的加入提高了电解质的玻璃化温度但降低了聚酯的熔点及结晶度。聚酯电解质的晶体类似于聚酯,其无机盐主要溶解于聚酯的无定形区域。聚酯系列电解质的导电率也有偶奇效应,与熔点变化相反;熔点高的电解质导电率低,熔点低的电解质导电率高。电解质的导电率随温度改变而变化,在室温下电解质的导电率可达10~(-6)s/cm。高分子链上侧基的引入将大大降低电解质的导电性。     

Structural white matter abnormalities in patients with idiopathic dystonia

We investigated whether structural white matter abnormalities, in the form of disruption of axonal coherence and integrity as measured with diffusion tensor imaging (DTI), constitute an underlying pathological mechanism of idiopathic dystonia (ID), independent of genotype status. We studied seven subjects with ID: all had cervical dystonia as their main symptom (one patient also had spasmodic dysphonia and two patients had concurrent generalized dystonia, both DYT1‐negative). We compared DTI MR images of patients with 10 controls, evaluating differences in mean diffusivity (MD) and fractional anisotropy (FA). ID was associated with increased FA values in the thalamus and adjacent white matter, and in the white matter underlying the middle frontal gyrus. ID was also associated with increase in MD in adjacent white matter to the pallidum and putamen bilaterally, left caudate, and in subcortical hemispheric regions, including the postcentral gyrus. Abnormal FA and MD in patients with ID indicate that abnormal axonal coherence and integrity contribute to the pathophysiology of dystonia. These findings suggest that ID is not only a functional disorder, but also associated with structural brain changes. Impaired connectivity and disrupted flow of information may contribute to the impairment of motor planning and regulation in dystonia. © 2006 Movement Disorder Society     

血管性认知功能损害的全脑DTI直方图分析

目的利用扩散张量成像(DTI)直方图分析,明确血管性认知损害(VCI)患者的脑异常改变及DTI直方图指标与简易智能量表(MMSE)评分的相关性。方法对19例VCI患者和19例健康志愿者行常规MRI和DTI检查,获得全脑平均扩散率(MD)和各向异性分数(FA)图像后,分别绘制出全脑FA和MD直方图并对其进行分析。结果VCI患者的全脑MD和FA直方图与正常志愿者不同。与正常对照比较,VCI患者平均全脑FA直方图示峰位置左移、平均FA值降低(P=0.008),MD直方图右移、平均MD值增高(P=0.026),峰位置增高(P=0.041),峰高降低(P=0.002)。平均FA值(r=-0.486,P=0.036)、FA峰高(r=0.498,P=0.030)和FA峰位置(r=-0.641,P=0.003)与MMSE评分相关。结论VCI的患者存在脑扩散异常,DTI直方图部分指标可以帮助评价认知功能损害的严重程度。     

直接甲醇燃料电池用阻醇质子导电聚乙烯醇-聚苯乙烯磺酸共混膜

制备了聚乙烯醇 (PVA)与聚苯乙烯磺酸 (PSSA)的共混膜 ,并研究了膜的组成、热处理温度、甲醇水溶液浓度等对膜电导率和甲醇透过率的影响。与目前普遍使用的NafionTM膜相比 ,这种由阻醇材料PVA与离子交换材料PSSA共混后形成的聚合物膜既能提高阻醇性能 ,又具有一定的电导率。一种以聚苯乙烯磺酸含量为 17%的膜 ,其电导率可达 3× 10 -3 S·cm-1,但甲醇透过率P仅为 2× 10 -8cm2 ·s-1。如果以σ/P为综合指标 ,则此膜的综合性能比NafionTM膜高约 4 0倍