首发和慢性精神分裂症幻听患者的扩散张量成像研究

目的:探索首发和慢性精神分裂症幻听患者是否存在听觉、语言及记忆/边缘系统网络的相关白质纤维异常。方法:纳入21例首发和12例慢性精神分裂症幻听患者及人口学参量匹配的26例健康对照。收集所有研究对象的DTI数据,采用基于纤维束的空间统计分析方法比较两组患者和对照组间的白质纤维差异。结果:与对照组相比,首发精神分裂症幻听患者在胼胝体、上纵束、下额枕束、钩束、扣带束、外囊及内囊前肢区域部分各向异性(FA)显著降低,径向扩散张量(RD)显著升高。慢性精神分裂症幻听患者表现出比首发患者更广泛的白质损害,且除FA和RD的改变外,部分脑区还表现出轴向扩散张量(AD)的升高。结论:精神分裂症幻听患者存在连接语言、听觉和记忆/边缘系统网络的多种白质纤维异常。慢性精神分裂症幻听患者与首发患者相比可能表现出更严重的神经退行性改变。     

采用基于纤维束示踪的空间统计分析方法观察阿尔茨海默病患者的脑白质改变

目的:采用基于纤维束空间统计分析(TBSS)法观察阿尔茨海默病(Alzheimer's disease,AD)患者弥散张量改变,以研究其全脑白质纤维束损害的特点。方法:选取24例AD患者和21例非神经系统疾病患者(对照者),对全脑进行DTI序列扫描。采用FSL软件内的TBSS软件包,对被试的DTI扫描数据进行预处理后,对AD患者及对照者的部分各向异性分数(FA)、图像进行基于体素的全脑非参数统计学比较。结果:与对照者相比,AD患者FA值明显减低的脑区包括穹窿和双侧额上回、额中回、左侧额下回白质束及双侧颞中回、右侧颞上回、左侧颞下回、左侧楔叶、右侧扣带束前部、胼胝体膝部、左侧扣带束后部、左侧海马白质束、右侧海马旁回白质束,而双侧丘脑及中脑皮质脊髓束FA值显著降低(P<0.05)。结论:采用TBSS分析方法具有相对客观性,本研究提示AD患者存在明显的白质束损伤,且范围累及较广,对了解AD脑白质异常的潜在神经生物学机制有重要价值。     

未经治疗的首发精神分裂症患者脑灰质非对称性改变:基于VBM的MRI结构研究

目的:采用核磁共振成像及优化的基于体素形态学研究(voxel based morphometry,VBM)新技术分析未经治疗的首发精神分裂症患者的脑结构非对称性改变。方法:对符合DSM-IV精神分裂症诊断标准,同时未经药物治疗的首发精神分裂症住院患者以及正常志愿者各20例进行核磁共振扫描脑结构成像及基于VBM的脑非对称性分析。结果:病例组较正常对照显示出明显的正常非对称性减低甚至反转的改变。正常右利手左半球优势区域如额上回、颞中回、扣带回、眶回、尾状核头以及丘脑的非对称性下降;中央后回非对称性反转;海马及海马旁回的右大于左的非对称性增加。结论:脑非对称性在未用药物治疗的首发精神分裂症患者中有明显的异常改变,提示精神分裂症患者存在原发的脑结构非对称性异常,脑非对称性紊乱的存在反映了神经异常发育与精神分裂症的发病的关联。精神分裂症患者存在的脑结构非对称性异常可能构成了精神分裂症的神经生物学表征。     

脑梗死偏瘫患者针刺下神经作用机制的血氧水平依赖性功能磁共振成像及弥散张量成像研究

目的 应用血氧水平依赖性功能磁共振成像（BLOD-fMRI）及磁共振弥散张量成像（DTI）技术观察脑梗死偏瘫患者神经纤维束的完整性及其脑功能区对针刺的反应,探讨神经纤维束损伤时针刺的神经作用机制。 方法 选取20例以左上肢偏瘫为主要症状的脑梗死患者,病程3～6周。对患者行DTI及针刺左侧合谷穴、外关穴任务下BOLD-fMRI检查。DTI原始数据经过处理后重建锥体束三维图像,观察右侧锥体束的损伤情况。BOLD-fMRI原始数据应用SPM 8等软件处理之后,观察脑功能激活区的分布情况。 结果 20例脑梗死患者右侧锥体束有不同程度的中断受损改变。脑梗死患者针刺左侧合谷穴、外关穴任务下,两侧基底核区核团及丘脑激活最为明显,左额内侧回、额上回、左岛叶有明显激活区域,中脑网状结构、红核、黑质及左小脑山坡、齿状核、右侧额叶皮质见大量激活区域,左颞下回、梭状回、左额中回、左额下回、两侧楔前叶、右小脑山坡、右顶叶皮质有少量激活区。负激活脑区包括左后扣带回、右枕叶及右额上回。 结论 DTI技术可直观反映脑梗死偏瘫患者的锥体束损伤情况,损伤时锥体外系在针刺效应中发挥了显著作用,DTI与BLOD-MRI联合应用对研究脑梗死患者的针刺康复机制具有重要价值。     

精神分裂症患者大脑灰质结构异常的VBM初步分析

目的评价基于体素的形态学分析法(VBM)分析精神分裂症大脑灰质结构的价值。方法采用GE Signa Twin Speed1.5T超导型MRI成像系统,对9例精神分裂症患者和9例年龄、性别与之相匹配的正常人行全脑扫描,获取16～18层脑结构MRT1图像。数据分析采用以SPM2软件包为基础的全自动VBM技术进行处理。结果与正常对照组比较,精神分裂症患者灰质明显减少区域在双侧前扣带回、前额叶、右侧颞上回(P<0.005),且大脑灰质减少具有不对称性,前额区偏侧化系数(AIs)为 0.19,颞区为-0.50。灰质明显增多的区域在右前额叶与右枕区、左顶下小叶(P<0.005),也具有不对称性,前额区AIs为-0.77,顶叶 1.00,枕区为-0.73。结论精神分裂症患者大脑灰质结构异常。VBM法具有简便、自动化的特点,在精神分裂症脑形态结构研究方面前景广阔。     

首发精神分裂症患者威斯康星卡片分类测验中的脑功能障碍研究

目的:探讨首发未服药精神分裂症患者进行威斯康星卡片分类测验(WCST)操作时的脑功能状态特点。方法:20名健康受试者(对照组)和20名首发未服药精神分裂症患者(患者组)操作WCST和颜色卡片分类测验(CCST)时进行脑功能磁共振成像(fMRI),比较2组激活脑区的激活体积。结果:对照组WCST和CCST功能图像相减获得的脑活动功能图像显示,激活主要分布在双侧前额叶,尤其是背外侧部以及顶叶后下部皮质和前扣带回。患者组WCST操作成绩较对照组差,有显著性差异(P<0.01)。与对照组相比,患者组的左侧前额叶背外侧部、左前扣带回皮质激活低下,左顶叶后下部皮质激活增加(P<0.01或0.05)。结论:双侧前额叶,尤其是背外侧部,以及顶叶后下部皮质和前扣带回皮质参与WCST操作的高级认知过程。精神分裂症患者在未治疗前就存在执行功能缺陷,其前额叶和扣带回功能低下,可能与患者执行功能障碍相关;后顶叶皮质功能亢进,可能对前额叶功能低下有补偿作用。     

针刺合谷穴脑功能磁共振成像研究

目的观察针刺合谷穴引发脑内相关区域的变化情况.方法对6名健康右利手年轻被试进行右手合谷穴针刺,同时进行全脑fMRI,对脑内活动区域进行定位.结果针刺合谷时引起双侧感觉/运动区,额中回,颞上回前部,丘脑,额上内侧回,双侧小脑,双侧枕颞交界区,对侧岛叶,扣带回前部,中央后回上部以及同侧顶盖区激活,而降低的区域则分别表现在双侧颞极部,内颞叶区,额下内侧回,额叶眶部,双侧颞中回,双侧扣带回后部,枕叶,双侧中央前回中部,同侧中央前回上部.结论针刺合谷能够引发脑内相关区域的激活和降低,说明fMRI能够为针灸机制的探讨提供帮助.     

慢性脊髓损伤后脑结构重塑的磁共振成像研究

目的 联合应用基于体素的形态学 (VBM) 研究和扩散张量成像(DTI)探讨慢性脊髓损伤(SCI)患者全脑灰、白质变化规律。方法 对20例慢性SCI患者(SCI组)和30名健康志愿者(对照组)行全脑容积及DTI扫描,分析患者全脑灰、白质结构改变及纤维束完整性的变化。结果 与对照组比较,SCI组脑灰质体积减小区域主要有左侧初级运动皮层(M1)、左侧运动前区(PMA)、右侧前扣带回、右侧直回、左侧额下回、右侧颞下回、左侧枕中回及右侧楔前叶 (P<0.001)。白质体积减小的区域主要有:双侧辅助运动区、双侧锥体束走行区、左侧M1及胼胝体 (P<0.001)。FA值减小的区域主要有胼胝体干、左侧内囊前肢及左侧顶下小叶。MD值增高的区域主要为胼胝体干,MD值减小的区域为右侧顶下小叶缘上回(P<0.001)。结论 慢性SC的相关脑结构区发生改变,与认知、情绪、空间定位功能相关脑区的灰、白质结构发生改变,其中胼胝体对结构的重塑可能起着重要作用。联合使用VBM及DTI可显示慢性SCI后脑结构的重塑。     

可逆性后部白质脑病综合征CT和MRI影像学特点分析

目的:探讨可逆性后部白质脑病综合征(reversible posterior leukoencephalopathy syndrome,RPLS)CT和MRI影像学特点.方法:回顾性分析9例RPLS患者的临床及CT和MRI影像学资料.结果:MRI显示6例双侧对称性枕叶白质受累,其中4例双侧额叶顶叶白质受累,1例同时累及中脑和丘脑,1例累及尾状核头;病灶形态不规则,特征表现为皮质及皮质下白质脑回样异常信号.CT显示枕叶低密度影,其中2例广泛脑白质水肿.治疗5～20 d复查,6例病灶部分消失,1例完全消失,2例出现转化灶.结论:结合临床特点和后部脑白质损害为主的影像学表现,有助于RPLS的诊断.     

弥散张量成像评价中老年患者全身麻醉后海马区纤维的完整性

目的:应用弥散张量成像技术(diffusion tensor imaging,DTI)比较中老年患者术前与接受全凭静脉麻醉术后海马旁回以及后扣带回白质纤维束的完整性。方法:对20例接受全凭静脉麻醉的老年患者进行术前简明精神状态量表(mini-mental state examination,MMSE)评分,并且进行术前1天及术后3天的功能磁共振扫描。分为术前组与术后组。术前组与术后组均为相同的患者。采用FSL软件对获取的磁共振图像数据进行处理,分别计算双侧海马旁回(hippocampal gyrus,PH),双侧后扣带回(posterior cingulate cortex,PCC)的各向异性分数(fractional anisotropy,FA)和表观弥散系数(apparent diff usion coefficient,ADC),利用SPSS软件进行统计学分析。结果:术后组双侧PH,双侧PCC的FA值较术前有所降低,ADC值较术前有所升高,差异有统计学意义(P0.05)。结论:全凭静脉麻醉术后老年患者的海马体部白质纤维束的完整性较术前有所损害。     

Determination of creatine kinase isoenzyme MB activity in serum using immunological inhibition of creatine kinase M subunit activity. Activity kinetics and diagnostic significance in myocardial infarction.

This is a new method for the determination of creatine kinase isoenzyme MB activity in serum. The method uses direct activity measurement of creatine kinase B subunit activity after blocking of CK-M subunit activity by inhibiting antibodies. The test takes no longer than 15 min. The method yields an intra-serial C.V. of 2.0-12.9%, and a C.V. from day to day of 5.5%. The detection limit is 3.4 U/l creatine kinase MB. In the 95 cases with proven myocardial infarction several types of creatine kinase MB activity kinetics could be determined. The percentage of creatine kinase MB of peak CK-total is 6-25%, with a mean of 11.1%. The amount of creatine kinase MB with respect to total CK activity after reinfarction is higher than the amount after initial infarction.     

Dissociable correlates of two classes of retrieval processing in prefrontal cortex

Although substantial evidence suggests that the prefrontal cortex (PFC) implements processes that are critical for accurate episodic memory judgments, the specific roles of different PFC subregions remain unclear. Here, we used event-related functional magnetic resonance imaging to distinguish between prefrontal activity related to operations that (1) influence processing of retrieval cues based on current task demands, or (2) are involved in monitoring the outputs of retrieval. Fourteen participants studied auditory words spoken by a male or female speaker and completed memory tests in which the stimuli were unstudied foil words and studied words spoken by either the same speaker at study, or the alternate speaker. On "general" test trials, participants were to determine whether each word was studied, regardless of the voice of the speaker, whereas on "specific" test trials, participants were to additionally distinguish between studied words that were spoken in the same voice or a different voice at study. Thus, on specific test trials, participants were explicitly required to attend to voice information in order to evaluate each test item. Anterior (right BA 10), dorsolateral prefrontal (right BA 46), and inferior frontal (bilateral BA 47/12) regions were more active during specific than during general trials. Activation in anterior and dorsolateral PFC was enhanced during specific test trials even in response to unstudied items, suggesting that activation in these regions was related to the differential processing of retrieval cues in the two tasks. In contrast, differences between specific and general test trials in inferior frontal regions (bilateral BA 47/12) were seen only for studied items, suggesting a role for these regions in post-retrieval monitoring processes. Results from this study are consistent with the idea that different PFC subregions implement distinct, but complementary processes that collectively support accurate episodic memory judgments.     

俯卧位通气对高海拔地区肺复张治疗无效急性呼吸窘迫综合征患者氧合的影响

目的 探讨俯卧位通气对高海拔地区肺复张术(RM)治疗无效急性呼吸窘迫综合征(ARDS)患者的治疗作用.方法 从海拔2260m的地区医院筛选RM治疗无效的41例ARDS患者[平均氧合指数( PaO2/FiO2)较RM前升高＜20％视为RM无效],依不同病因分为肺内源性ARDS组(ARDSp组)和肺外源性ARDS组(ARDSexp组),每组再按信封法随机分为俯卧位组和仰卧位组,即ARDSp俯卧位组(11例)、ARDSp仰卧位组(9例)、ARDSexp俯卧位组(10例)、ARDSexp仰卧位组(11例).在通气前及通气1、2、3、4h监测动脉血氧分压( PaO2)、PaO2/FiO2、静态顺应性(Cst)、气道阻力(Raw)的变化.结果 通气lh时,ARDSexp俯卧位组PaO2/FiO2( mm Hg,l mm Hg=0.133 kPa)即较通气前显著升高(157.4±40.6比129.3±48.7,P＜0.05),并随通气时间延长呈持续增高趋势,4h达峰值(219.1 ±41.1);且ARDSexp俯卧位组通气3h内PaO2/FiO2较其他3组显著增高,另3组间则差异无统计学意义.ARDSp俯卧位组、ARDSexp俯卧位组通气4h时PaO2/FiO2均较相应仰卧位组显著增高(208.8±39.7比127.4±47.1,219.1±41.1比124.9±50.8,均P＜0.05).4组通气前后Cst无显著改变,各组间差异也无统计学意义.ARDSp俯卧位组通气4h时Raw(cmH2O·L-1·s-1)较通气前显著降低(6.8±1.7比10.7±1.8,P＜0.05),且明显低于其他3组;其他3组各时间点Raw组内及组间比较差异均无统计学意义.结论 俯卧位通气作为ARDS机械通气重要策略之一,可以改善RM无效高原ARDS患者的氧合,为抢救患者赢得宝贵的时间.     

Digital imaging among medical facilities

The Department of Veterans Affairs (VA) in the USA operates a network of 172 medical centres which all utilize a hospital information system (HIS) which has been developed and is currently maintained by the VA. During the past several years, an image management and communication module has been developed, installed and clinically utilized at the Washington DC and Maryland VA Medical Centres. This image management and communication system, referred to as the decentralized hospital computer program (DHCP) imaging system, is fully integrated with a commercial picture archiving and communication system (PACS). The system is utilized to capture, archive, and display all images generated within the hospital including radiology, nuclear medicine, pathology, endoscopy, bronchoscopy, and dermatology, intraoperative photographs, ECG data, and a limited number of paper documents. The ultimate goal of the project is to have all patient text and image data available at any clinical workstation to any authorized user anywhere within the network of medical centres. Clinical requirements for an imaging workstation include ease of use, rapid and reliable access to the complete set of patient information, and images which are of acceptable quality to meet the requirements of the user and the subspecialty. Patient confidentiality and data security must be safeguarded at all times. Integration of the images with the remainder of the patient's database was found to be critical to the success of the project. The experience at the Washington and Maryland facilities suggests that an imaging system that is successfully integrated with a hospital information system can provide substantial clinical and economic benefits both within and among medical centres. Clinical acceptance and utilization of the system has been excellent, particularly in diagnostic radiology where DHCP Imaging has been interfaced to a commercial PAC system. Based upon this initial experience, the VA has begun to deploy the system throughout its large network of medical centres.     

Myocardial elastography at both high temporal and spatial resolution for the detection of infarcts

Myocardial elastography is a novel method for noninvasively assessing regional myocardial function, with the advantages of high spatial and temporal resolution and high signal-to-noise ratio (SNR). In this paper, in-vivo experiments were performed in anesthetized normal and infarcted mice (one day after left anterior descending coronary artery [LAD] ligation) using a high-resolution (30 MHz) ultrasound system (Vevo 770, VisualSonics Inc., Toronto, ON, Canada). Radiofrequency (RF) signals of the left ventricle (LV) in longitudinal (long-axis) view and the associated electrocardiogram (ECG) were simultaneously acquired. Using a retrospective ECG gating technique, 2-D full field-of-view RF frames were acquired at an extremely high frame rate (8 kHz) that resulted in high-quality incremental displacement and strain estimation of the myocardium. The incremental results were further accumulated to obtain the cumulative displacements and strains. Two-dimensional and M-mode displacement images and strain images (elastograms), as well as displacement and strain profiles as a function of time, were compared between normal and infarcted mice. Incremental results clearly depicted cardiac events including LV contraction, LV relaxation and isovolumetric phases in both normal and infarcted mice, and also evidently indicated reduced motion and deformation in the infarcted myocardium. The elastograms indicated that the infarcted regions underwent thinning during systole rather than thickening, as in the normal case. The cumulative elastograms were found to have higher elastographic SNR (SNR(e)) than the incremental elastograms (e.g., 10.6 vs. 4.7 in a normal myocardium, and 6.0 vs. 2.4 in an infarcted myocardium). Finally, preliminary statistical results from nine normal (m = 9) and seven infarcted (n = 7) mice indicated the capability of the cumulative strain in differentiating infracted from normal myocardia. In conclusion, myocardial elastography could provide regional strain information at simultaneously high temporal (>/=0.125 ms) and spatial ( approximately 55 microm) resolution as well as high precision ( approximately 0.05 microm displacement). This technique was thus capable of accurately characterizing normal myocardial function throughout an entire cardiac cycle, at the same high resolution, and detecting and localizing myocardial infarction in vivo.     

Clinical Pharmacokinetics of Morphine

Morphine, the most widely used mu-opioid analgesic for acute and chronic pain, is the standard against which new analgesics are measured. A thorough understanding of the pharmacokinetics of morphine is required in order to safely and effectively use this analgesic in a wide variety of patients with different levels of organ function. A MEDLINE search was conducted to identify literature published between 1966 and January 2002 relevant to the pharmacokinetics of morphine. These publications were reviewed and the literature summarized regarding unique and clinically important elements of morphine disposition relative to its parenteral administration (including intravenous, intramuscular, subcutaneous, epidural and intrathecal administration), absorption profile (immediate release, controlled release, and sublingual/buccal, and rectal administration), distribution, and its metabolism/ excretion. Special populations, including infants, elderly, and those with renal/liver failure, have a unique morphine pharmacokinetic profile that must be taken into account in order to maximize analgesic efficacy and reduce the risk of adverse events.