经静脉实时心肌声学造影对犬正常心肌灌注的定量评价

目的：探讨实时心肌声学造影定量评价犬正常心肌灌注的可行性。方法：20只开胸犬以5ml/min和10ml/min速度静滴“全氟显、进行实时心肌声学造影，左室乳头肌短轴观察左室心肌显影效果和室壁运动，闪烁显像观察心肌灌注，动态图像单帧转化后以图像软件分析造影结果。结果：静滴速度10ml/min时，心脏各部位显影时间短于5ml/min，闪烁显像时心肌再灌注速度也略快，心肌显影稳定后二者间视频亮度峰值无明显差异，均可看到舒张期／收缩期的时相性变化，同时室壁运动显示良好。结论：实时心肌声学造影可同时观察心肌灌注和室壁运动，闪烁显像可观察心肌再灌注过程，但缺少联机分析软件限制了造影结果的分析。     

实时心肌声学造影评价正常犬心肌血流灌注的实验研究

目的：应用实时心肌声学造影评价正常犬的心肌血流灌注。方法：8只开胸犬以微量注射泵静脉滴注全氟显（速度为5ml/min和10ml/min）进行实时心肌声学造影。乳头肌水平短轴切面观察左室各壁的造影效果和室壁运动。以闪烁显像观察左室各壁的再注情况。结果：实时心肌声学造影良好地显示了犬正常心肌的血流灌注特点,包括色彩、亮度与灌注时间,同时各室壁节段运动显示良好,回放测量与M型测值无明显差异,闪烁显像准确反映了心肌血流灌注的速度。结论：实时心肌声学造影可同时观察心肌灌注和室壁运动,“闪烁”显像具有定量评价心肌血流灌注的潜在价值,具有良好的应用前景。     

实时心肌声学造影的仪器设置与显像效果的影响因素

目的：探讨实时心肌声学造影的仪器设置及显像效果的影响因素。方法：8只开胸充微量注射泵静脉滴注氟碳类造影剂全氟显（速度为5ml/min和10ml/min)进行实时心肌声学造影。调节仪器设置如增益,量程及深度等参数,于左室乳头肌水平短轴切面观察心肌显影的不同效果。结果：实时心肌声学造影可同时显示心肌血流灌注和室壁运动,除降低接受增益至50％,使用默认的仪器设置即可获得良好的造影效果,闪烁显像时最佳闪烁帧数为5个。结论：实时心肌声学造影易于掌握,影响因素较少,可同时观察心肌灌注和室壁运动,闪烁显像具有定量评价心肌血流灌注的潜力。     

定量门控^99Tc^m—甲氧基异丁基异腈心肌显像评价局部室壁运动的可靠性

目的：与二维超声心动图检查结果比较，探讨定量门控^99Tc^m—甲氧基异丁基异腈(MIBI)心肌显像评价局部室壁运动的可靠性。方法：研究对象为1997—10／2000—09暨南大学医学院第一附属医院核医学科接受门控^99Tc^m—MIBI心肌显像和二维超声心动图检查的不同左室功能的受试者。对158例不同左室功能受试者进行门控^99Tc^m—MIBI心肌显像，采用QGSPECT程序评价左室总体和各区域局部室壁运动。并与静态二维超声心动图进行比较。结果：左室总体局部室壁运动：定量门控^99Tc^m—MIBI心肌显像评价室壁运动与超声心动图的结果基本符合(观察符合率88．3％，Kappa=0．63，P&;lt;0．01)。左室各区域局部室壁运动：定量门控^99Tc^m—MIBI心肌显像能较准确评价左室前壁、前侧壁、后侧壁、下壁、前间壁、后间壁和后壁局部室壁运动(观察符合率分别为94．9％，92．0％，96．2％，93．0％，81．0％，77．2％，86．7％，81．0％，Kappa=0．46～0．74，P&;lt;0．01)。结论：定量门控^99Tc^m—MIBI心肌显像能较准确评价室壁运动，为患者心功能预后评价提供临床依据。     

超声组织同步显像技术评价肥厚性心肌病患者心肌收缩协调性的初步研究

目的探讨超声组织同步显像技术评价肥厚性心肌病心肌收缩协调性的临床价值。方法14例肥厚性心肌病（HCM）患者和20例正常人，采用实时三平面组织同步显像技术，同步实时获取心尖四腔观、左室心尖两腔观和左室心尖长轴观，通过绿黄红三种颜色半定量显示局部心肌收缩达峰时间（TTP）。采用牛眼图模式分别定量测量HCM组和正常组左室6个壁12个心肌节段的纵轴收缩达峰时间，分别比较：①HCM组与正常组室间隔中段TTP；②HCM组与正常组左室后壁TTP；③HCM组肥厚节段和非肥厚节段TTP。结果HCM组室间隔中段TTP较正常组室间隔中段TTP明显延迟（P〈0．01），HCM组左室后壁TTP较正常组左室后壁TTP明显延迟（P〈0．05），HCM组肥厚节段TTP较非肥厚节段明显延迟（P〈0．05）。结论HCM患者肥厚心肌与非肥厚心肌收缩不协调，组织同步显像技术能对其进行准确评价。     

经静脉实时心肌声学造影评价犬急性心肌梗死的实验研究

目的 研究实时心肌声学造影检出犬急性心肌梗死的效果。方法 8只开胸犬结扎第一对角支起点以下冠脉左前降支主干,分别于结扎前、结扎后1h和3h静滴全氟显（5ml/min）进行实时心肌声学造影,左室乳头肌水平短轴切面观察造影效果和室壁运动,并与病理染色比较。结果 结扎后1h及3h,实时心肌声学造均能良好显示缺血区的造影剂充盈缺损,包括缺损大小、与形态,同时清楚显示缺血区室壁运动异常。与病理染色比较,充盈缺损区大于心梗区。闪烁显像很好反映出充盈缺损区周围心肌轿流再灌注减慢。结论 与病理染色比较,充盈缺损区大于心梗区。闪烁显像很好反映出充盈缺损区周围心肌血流再灌注减慢。结论 实时心肌声学造影可同时观察心肌灌注和室壁运动,闪烁显有定量评价心肌血流灌注的潜在价值,操作简便,具有良好的应用前景。     

心肌代谢和灌注不匹配的定量评价 及心功能恢复的预测

目的　定量评价急性心肌梗死 (AMI)再灌注后心肌代谢和血流灌注不匹配区域与发病 1个月后左室功能恢复之间的关系。方法　接受再灌注治疗的AMI患者 18例 ,1周内实施2 0 1TlCl和12 3 I β 甲基碘苯十五烷酸 (12 3 I BMIPP)双核素心肌断层显像并制成BMIPP/Tl图像 ,分析BMIPP/Tl异常区域与 1个月后左室功能恢复之间的关系。结果　BMIPP/Tl在 0 .94～ 0 .85区域的像数与 1个月后左室射血分数和室壁运动计分的改善 (ΔLVEF和ΔWMS)之间呈显著正相关 ,但BMIPP/Tl<0 .85区域的像数和ΔLVEF和ΔWMS不相关。结论　应用BMIPP/Tl图像定量评价AMI再灌注后心肌代谢和灌注的不匹配程度 ,可以客观地评价疗效和预测慢性期心功能的恢复 ,有十分重要的临床意义。     

实时心肌造影评价肥厚型心肌病患者心内膜下及心外膜下心肌灌注

目的应用实时心肌超声造影分析肥厚型心肌病（HCM）患者心内膜下及心外膜下心肌灌注状况,及其与室壁肥厚程度的关系,以评价肥厚型心肌病患者心肌微循环障碍。方法HCM患者26例,正常对照组20例,实时心肌超声造影观察心尖四腔、两腔、左心长轴切面实时动态图像,应用时间～强度曲线分析造影图像。结果HCM患者左室肥厚节段及非肥厚心肌节段的心内膜下及心外膜下心肌的A及A×k值低于对照组（P〈0．05）,k值高于对照组（P〈0．001）。HCM患者左室肥厚节段心内膜下及心外膜下心肌的的A及A×k值低于非肥厚心肌节段（P〈0．05）,k值高于非肥厚心肌节段（P〈0．05）。HCM患者心内膜下A、及A×k值低于下心外膜下（P〈0．001）。HCM患者肥厚节段心内膜下及心外膜下心肌A×k值与肥厚节段室壁厚度均呈负相关（r=-0．785,P〈0．001;r=-0．461,P〈0．05）。结论HCM患者肥厚节段与非肥厚节段的心内膜下及心外膜下心肌均存在微循环障碍,且以心内膜下心肌微循环损伤更为显著,同时,随着室壁厚度的增加,心肌血流灌注显著减少。实时心肌超声造影是评价HCM患者心肌微循环障碍的有效方法。     

实时三平面组织多普勒超声心动图评价心脏手术对左心室局部收缩功能的影响

目的探讨实时三平面组织多普勒成像技术定量评价心脏手术对左心室局部收缩功能影响的价值。方法应用实时三平面定量组织速度显像技术，采集22例心脏手术患者术前和术后心尖四腔观三平面组织速度图像，将后间隔、左室侧壁、前壁、下壁、前间隔和后壁分别按基底段和中间段划分为12个节段，测量各个节段的收缩期峰值速度和峰值位移。取胸骨旁左室长轴观，用M型测量左室射血分数和缩短率。结果术后左室12个节段的收缩期峰值位移测值均比术前明显减低（P〈0．05）；后间隔、下壁和前间隔的基底段和中间段及后壁基底段的收缩期峰值速度测值也明显低于术前（P〈0．05）。左室缩短率和左室射血分数测值与术前相比，差异无显著性意义（P〉0．05）。结论心脏手术过程损害左室局部心肌的收缩功能，实时三平面组织速度显像技术能准确评价术后患者左室局部收缩功能的改变。     

应用间歇触发显像技术定量各节段心肌血流的可行性及准确性研究

目的　应用自制的声学造影剂 ,建立谐波能量多普勒间歇触发显像技术 (ITI)定量节段心肌血流量的完整方法 ,并评价该技术定量心肌血流 (MBF)的准确性和可行性。方法　取 6条开胸犬 ,显示乳头肌中部水平短轴切面 ,静脉连续滴注造影剂 ,分别在基础状态、静脉给予潘生丁造成的充血状态及充血状态下左冠状动脉回旋支 (LCx)不同程度狭窄状态进行心肌造影超声心动图 ,将左室壁分成前壁、侧壁、后壁、下壁、后间隔和前间隔 6个节段分析。在最后狭窄状态 ,于心肌声学造影 (MCE)结束后左房内注入放射性微球 (MIC)测量MBF ,并与ITI测值进行对比。结果　在各节段显像中 ,位于聚焦区附近的前间隔和后壁的显像成功率最高 ,均为 88% ( 2 9/ 3 3 ) ,位于近场的侧壁显像成功率最低 ,为 61% ( 2 0 / 3 3 )。标准化后ITI测量的后壁 /前壁、后壁 /侧壁及后壁 /前间隔的MBF比值与MIC测值相关 ,其中以后壁 /前间隔的相关性最强(r =0 .97,P <0 .0 0 1)。非缺血区ITI测得的MBF绝对值 (前壁、下壁、后间隔和前间隔 )和MBF比值 (前间隔 /前壁、前间隔 /下壁、前间隔 /后间隔 )与MIC测值相关有显著性 ,但相关性较差 (r =0 .5 2 ,P =0 .0 1和r =0 .44 ,P =0 .0 1)。在缺血区 (后壁和侧壁 ) ,ITI测得的MBF绝对值和MBF比值 (前间隔 /侧     

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.