定量组织速度成像技术对肥厚型心肌病收缩及舒张功能的评价

目的应用定量组织速度成像技术(QTVI)评价肥厚型心肌病(HCM)患者左心室长轴方向上的收缩和舒张功能。方法应用QTVI技术离线分析24例HCM患者和22例正常对照者左心室各心肌节段长轴方向上的速度曲线,测量收缩期峰值(Vs)、舒张早期峰值(Ve)和舒张晚期峰值速度(Va),并计算Ve/Va及收缩期和舒张早期心肌速度梯度(MVG)。结果HCM组收缩期和舒张早期MVG及各室壁基段、中段和部分尖段的Vs、Ve及Ve/Va均小于对照组,而Va与对照组间的差异无统计学意义;肥厚最为明显的节段(后室间隔中段)的Vs与相应侧壁节段的比值小于对照组,后室间隔中段的Vs、Ve与该节段的厚度呈负相关。结论HCM患者左心室长轴方向上的收缩及主动舒张功能受损,并同时累及肥厚及非肥厚的室壁,以肥厚的室壁最为明显。肥厚心肌的舒缩功能与心肌的厚度呈负相关。     

定量组织速度成像技术评价扩张型心肌病左室心肌功能的研究

目的探讨定量组织多普勒速度成像(QTVI)技术评价扩张型心肌病(DCM)患者左室心肌收缩与舒张功能的价值.方法应用QTVI获取30例正常人和30例DCM患者左室长轴方向不同室壁节段即左室前壁、后壁、下壁、侧壁及室间隔的心肌多普勒速度曲线,分别比较以下参数1. 正常人上述不同室壁中部心肌运动收缩期峰值速度(Vs)、收缩期加速度(a)、快速充盈期和心房收缩期的速度(Ve和Va)、收缩期内外膜峰值速度阶差(MVG);2.DCM患者不同左室壁中部的Vs、Ve、Va、MVG、a的差异;3.正常人与 DCM患者左室壁中部的Vs、Ve、Va、MVG、a的差异;4.正常人与DCM患者二尖瓣口舒张期血流频谱E/A值、左室射血分数(LVEF)、Vs/Ve比值.结果 (1)DCM患者Vs、Ve、Va、MVG、a、LVEF均比正常人明显降低;(2)以a>65cm/s2、Vs/Ve>0.83作为判定患者心功能符合临床NYHA分级Ⅰ～Ⅱ级、客观评分A～B级、LVEF>35%的界定值,其敏感性91%,特异性74%,阳性预测值83%.结论 QTVI定量评价DCM患者左室心肌功能,为进一步了解DCM患者局部心肌收缩舒张功能变化及其局部与整体心肌功能之间的关系提供较为敏感、精确的方法.     

定量组织多普勒技术评价糖尿病患者左室功能

目的探讨定量组织多普勒技术(QTVI)技术评价糖尿病(DM)患者左室心肌收缩与舒张功能的价值.方法应用QTVI获取35例正常人和48例DM患者左室长轴方向不同室壁节段即左室前壁、后壁、下壁、侧壁及室间隔的心肌多普勒速度曲线,分别比较以下参数1.不同室壁中部心肌运动收缩期峰值速度(Vs)、快速充盈期和心房收缩期的速度(Ve和Va);2.二尖瓣舒张期血流频谱E/A值、左室射血分数(LVEF)、LVMI(左室质量指数)、Vs/Ve比值.结果 (1)DM患者Vs、Ve、Va、Vs/Ve 、LVEF均比正常人降低(P＜0.05);(2) 若以Vs>4.5 cm/s、Vs/Ve>0.80、LVEF>45%作为判定患者心功能符合临床NYHA分级Ⅰ～Ⅱ级、客观评分A～B级的界定值,其敏感性80%,特异性85%,阳性预测值86%;(3)DM患者Vs 的测值越低,临床NYHA分级越差,它们之间有一定的负相关性(r＝-0.75).结论 QTVI定量评价DM患者左室心肌功能,为进一步了解DM局部心肌收缩舒张功能变化及其局部与整体心肌功能的变化提供较为敏感、精确的方法.     

定量组织速度成像对肥厚型心肌病左心室局部心肌舒张功能的分析

目的探讨定量组织速度成像（QTVI）评价肥厚型心肌病（HCM）患者左室局部心肌舒张功能的价值。方法获标准心尖长轴切面、心尖二腔切面和心尖四腔切面，应用QTVI技术分析17例HCM患者和18例健康者左室长轴方向不同室壁节段的多普勒速度曲线，测量各节段心肌运动舒张早期峰值速度（Ve）和舒张晚期峰值速度（Va），计算左室二尖瓣环、基底段、中段水平的平均Ve、平均Va。应用脉冲多普勒技术分别测量二尖瓣口舒张早期峰值速率（E）、舒张晚期速率（A）、计算E／A。结果HCM组左室各节段Ve明显低于正常组（大部分P〈0．001），肥厚节段Va低于正常组（P〈0．05），而非肥厚节段Va两组间差异无显著性意义（P〉0．05）。两组同一水平平均Ve、Va的比较均有显著性意义（P〈0．05）。HCM组与正常组二尖瓣口E、A、E／A差异无显著性意义（P〉0．05）。结论QTVI能定量评价HCM患者左室局部心肌舒张功能。HCM患者左室长轴各节段心肌松弛性显著降低，肥厚节段的心肌顺应性受损。     

定量组织速度成像技术评价冠心病左心室局部心肌收缩与舒张功能的研究

目的探讨定量组织速度成像（QTVI）技术评价冠心病（CAD）患者左心室心肌收缩与舒张功能的价值。方法应用QTVI获取35例正常人和35例CAD患者左心室长轴方向不同室壁节段的心肌多普勒速度曲线,分析并比较收缩期峰值速度（Vs）、收缩期加速度（a）、快速充盈期和心房收缩期的速度（Ve和Va）、二尖瓣舒张期血流频谱E／A值、左心室射血分数（LVEF）、左心室质量指数（LVMI）、Vs／Ve、Va／Ve比值。结果CAD患者Vs、Ve、Va、a、Vs／Ve、LVEF均比正常人降低;CAD患者Vs的测值与临床NYHA分级有相关性（r=0．73）,Ve／Va与E／A有明显相关关系（r=0．74）。结论QTVI定量提供了一种较精确的评价CAD患者左心室局部心肌收缩舒张功能变化方法。     

定量组织速度成像对肥厚型心肌病患者左心室局部收缩功能的研究

目的　应用定量组织速度成像 (QTVI)评价肥厚型心肌病 (HCM)患者左心室局部收缩功能。方法　应用QTVI离线分析 3 1例HCM患者和 2 0例正常对照者左室长轴和短轴方向各心肌节段的速度曲线 ,测量收缩期峰值速度 (Vs) ,计算左室后壁和室间隔各心肌节段在长轴与短轴方向速度的比值。结果　HCM组肥厚与非肥厚心肌节段的平均Vs降低 ,与对照组相比 ,绝大部分心肌节段差异有显著性意义 (P<0 .0 5) ,但HCM组肥厚与非肥厚心肌节段的平均Vs之间差异无显著性意义 (P >0 .0 5)。正常人长轴与短轴方向速度的比值均 >1,而HCM患者其比值明显降低 ,大部分比值 <1。结论　HCM患者尽管左室射血分数正常 ,但左室长轴方向各心肌节段收缩功能受损 ,损害不仅发生在肥厚的左室壁 ,非肥厚的室壁同样受到损害 ;QTVI能定量评价HCM患者左室局部收缩功能     

多普勒组织成像技术在鉴别生理性与高血压性左室肥厚诊断中的价值

目的:探讨应用多普勒组织成像(DTI)技术对生理性肥厚和高血压性左心室肥厚进行鉴别,并对高血压左心室肥厚的左心室功能进行评价。方法:研究对象为28例经临床与超声诊断的高血压左心室肥厚患者(高心组)、8例有心肌肥厚的职业运动员(运动员组)和22例正常人(对照组)。应用DTI技术测量各组室间隔及左室后壁收缩期,舒张早、晚期峰值运动速度(分别是Vs,Ve,Va)、内外膜峰值速度差(ΔV)及峰值速度阶差(VG)、Ve?蛐Va比值、等容收缩期及等容舒张期心肌运动频谱持续时间(IVC,IVR),并进行比较。结果:运动员组各期的峰值速度及速度阶差与正常对照组无明显差别。高血压性心肌肥厚组虽反映心室整体收缩功能指标EF是正常的,但是其E波运动速度及Ve、舒张早期速度阶差(VGe)均较正常组和运动员组有显著下降。结论:DTI技术可实时、准确地反映心肌舒缩功能状况,并可依此对生理性肥厚心肌和高血压左心室肥厚进行鉴别。     

定量组织速度成像测定二尖瓣环运动速度对尿毒症患者左心舒张功能的评价

目的应用定量组织速度成像(QTVI)测定二尖瓣环运动速度评价尿毒症病患者左室舒张功能。方法应用定量组织速度成像测定30例正常人和32例尿毒症患者的二尖瓣环舒张早期峰值速度(Ve)、左房收缩期峰值速度(Va),计算Ve/Va比值;并用脉冲多普勒测定二尖瓣口舒张早期峰值血流速度E峰、舒张晚期峰值血流速度A峰,计算E/A值。结果正常组舒张早期峰值速度(E)>左房收缩期峰值速度(A),E/A>1;二尖瓣环舒张早期峰值速度(Ve)>左房收缩期峰值速度(Va),Ve/Va>1,正常组与尿毒症患者组二尖瓣口血流频谱及二尖瓣环运动组织速度成像测值有显著性差异,尿毒症患者组中二尖瓣环运动速度Ve/Va与二尖瓣血流频谱V/A无显著性差异。但在检出病例数中QTVI阳性例数明显高于血流频谱。结论应用定量组织速度成像测定二尖瓣口运动速度能较准确估计尿毒症患者左室舒张功能。     

定量组织速度成像对心肌梗死患者左室心肌纵向运动速度及速度梯度的研究

定量组织速度成像(QTVI)是基于组织多普勒成像(TDI)技术的可同时对多点心肌取样获得全心动周期的速度曲线的新技术.本文应用该技术对心肌梗死患者及正常人左室壁各心肌节段的收缩期峰速(Vs)及舒张早期峰速(Ve)进行研究,探讨心肌运动速度及心肌速度梯度(MVG)在判断心肌梗死患者左室局部心肌功能的价值.     

组织多普勒评价高血压患者的左室舒张功能

目的:应用组织多普勒与左室舒张末压对比评价高血压患者左室舒张功能,探讨组织多普勒评价左室舒张功能的临床价值。方法:50例高血压患者,分为左室肥厚组与非左室肥厚组,选取23例健康人作为对照组,分别行超声多普勒及组织多普勒检查,多普勒超声测量二尖瓣口舒张早期充盈速度(E)和舒张晚期充盈速度(A)及E/A,组织多普勒模式测量二尖瓣环舒张早期运动速度(Ve)、舒张晚期运动速度(Va)和Ve/Va,以及用猪尾导管直接测量左室舒张末压。结果:与对照组相比,高血压组的Ve/Va显著减小(P<0.05),且左室肥厚组的Ve/Va比非左室肥厚组减小的更为明显(P<0.05)。室间隔厚度与Ve/Va、E/A呈负相关(r分别为-0.77和-0.70,P<0.05),Ve/Va与室间隔厚度的相关性明显高于E/A与室间隔厚度的相关性。结论:组织多普勒可作为评价高血压左室舒张功能的可靠方法。     

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.