急性心肌梗塞再灌注治疗后心肌无复流现象的动态观察--相干对比成像技术的临床应用研究

目的应用相干对比成像(CCI)技术行静脉心肌声学造影(MCE),评价AMI再灌注治疗后心肌微循环灌注的动态变化.方法32例AMI在梗塞相关动脉(IRA)成功重建后12小时、1周、2周和4周行MCE,评价梗塞区心肌灌注和功能.结果IRA重建后12小时,11例表现心肌无复流现象(MCES为2分或3分,标疉β值为0.23±0.17),室壁运动消失(WMS在3分以上),其中10例术后4周随访心肌灌注和运动均无显著变化(P＞0.05),1例心肌灌注与室壁运动明显改善(P＜0.05);21例心肌灌注良好(MCES为1分,标化的A*β值为0.89±0.10),绝大部分室壁运动无明显异常(WMS≤2分),术后4周随访心肌灌注和运动均无显著变化(P＞0.05).结论AMI成功再灌注治疗后早期,约1/3患者可表现为低或无现象,4周随访大多数无改善.     

实时心肌声学造影与二维应变成像技术评价心肌梗死后患者心肌存活性

目的 探讨实时心肌声学造影与二维应变成像技术评价心肌梗死后患者存活心肌的价值.方法 20例准备进行血运重建术心肌梗死患者,于术前1周内行实时心肌造影检查,根据心肌灌注结果进行半定量评价:3分为充盈缺损,2分为回声稀疏不均匀及心内膜下充盈缺损,1分为回声均匀性增强;MCE定义心肌存活性为心肌灌注计分≤2分,而心肌充盈缺损表示无心肌存活性.血运重建术前及术后3个月分别获取心尖位四腔、两腔及左心长轴切面二维图象,进行室壁运动评分,根据术后的室壁运动有否改善分为存活心肌组和无存活心肌组,测定术前左室各节段心肌的收缩期纵向峰值应变.结果 (1) 血运重建术前,二维超声心动图发现共有90个室壁明显发生节段性运动异常,其中有70个室壁的节段性运动异常术后得到改善.(2)血运重建术前,实时心肌声学造影评价存活心肌为65节段,无存活心肌为25节段,敏感性、特异性及准确性分别为93.8%、64%和85.5%.(3) 存活心肌组术前心肌收缩期纵向峰值应变明显高于无存活心肌组[(-7.34±5.84)% vs (-2.11±1.66)%,P＜0.001].以术前心肌收缩期纵向峰值应变≤-5.0%作为截断值判断心肌梗死时存活心肌的敏感性为72%,特异性为85%.结论 实时心肌声学造影可以准确地预测梗死心肌的存活性;同时二维应变成像技术以术前心肌收缩期纵向峰值应变≤-5.0%作为截断值也可以预测梗死心肌的存活性,其敏感性和特异性与实时心肌声学造影相当.     

超声造影在心脏瓣膜置换术前筛查冠心病的初步研究

目的 研究心肌超声造影(myocardial contrast echocardiography,MCE)用于心脏瓣膜病患者术前筛查合并冠心病(coronaryartery disease,CAD)的可行性及准确性.方法 对16例中老年心脏瓣膜病患者行MCE检查.以冠状动脉造影(coronary angiography,CAG)作为参考标准进行分组,观察指标包括:A、β和A×β值,建立ROC曲线并计算敏感性及特异性.结果 A×β预测中老年瓣膜病合并CAD的ROC曲线,曲线下面积为0.70,以A×β值≤2.12预测其敏感性71.0%,特异性60.9%.将CAG结果阴性者,按照瓣膜病变累及部位分组比较,A、β、A×β值均无统计学差异,P＞0.05.结论 与CAG相比较,MCE定量分析有较高的敏感性及特异性,可以作为中老年瓣膜病合并CAD的术前筛查手段.     

心肌声学造影评价心肌梗塞后残余狭窄的临床应用

目的：前瞻性评价心肌声学造影（Myocardial Contrast Echocardiography,MCE）对心肌梗塞后残余狭窄的应用价值。方法：用间歇二次谐波，脉冲反转显像综合技术对36例心肌梗塞患者行静脉MCE检查，采用16段划分法，对心肌显影进行日测半定量计分分析，计分方法（MCS），回声均匀性增强，显影时间≤90秒为1分；回声像淡不均匀，显影延时（＞90秒）为0．5分，充盈缺损为0分。结果：以冠脉造影梗塞支冠脉直径狭窄≥50％为诊断标准，MCE检出残余余狭窄的敏感性88．6％，特异性75．0％，准确性87．2％，心肌灌注异常程度与冠脉残余狭窄程度无相关,r=0.36。结论：MCE技术能较准确的评估心肌梗塞相关冠脉残余狭窄，但心肌显影程度与冠脉残余狭窄程度无相关。     

多巴酚丁胺负荷试验中多普勒组织成像技术的应用价值

目的　静息状态与大剂量多巴酚丁胺 (Dob)负荷状态下 ,采用多普勒组织成像 (DTI)技术观察冠心病患者室壁运动 ,探讨大剂量 Dob负荷试验中 DTI检测冠心病的应用价值。方法　采用 DTI测量大剂量 Dob负荷试验中 32例冠心病患者 (至少 1支冠状动脉主支狭窄≥ 5 0 % )静息状态、峰值负荷下侧壁、后室间隔、前壁、下壁心肌基底段、中段心内膜下心肌运动频谱 ,对照组 2 5例相应节段作对照。 DTI分析指标 :收缩期峰值运动速度 (Vs)。结果　选择性冠状动脉造影结果将冠心病组患者心肌节段区分为正常节段与缺血节段。静息状态下 ,冠心病缺血节段(abnormal,A组 )与对照组相应正常节段 (normal,N组 )间 Vs无显著性差异 ;与 N组比较 ,峰值负荷下 A组各节段 Vs明显降低 (P<0 .0 5 ) ;以选择性冠状动脉造影为诊断冠心病的金标准 ,将峰值负荷下基底段心肌 Vs≤ 11.5 cm/ s,中段心肌 Vs≤ 9.5 cm/s为诊断冠状动脉狭窄的截断值 ,DTI结合大剂量多巴酚丁胺负荷试验诊断冠状动脉狭窄的敏感性、特异性、准确率分别为 85 .7%、84 .0 %、 84 .8% ;与常规多巴酚丁胺负荷超声心动图中室壁运动评分 (WMS)比较 ,DTI结合大剂量多巴酚丁胺负荷试验诊断冠状动脉狭窄的特异性与其并无显著差异 ;而敏感性、准确率显著增高 (P<0 .0 1)。结     

心肌声学造影在急性心肌梗死患者中的临床应用

目的　探讨利声显经静脉心肌声学造影 (IMCE)在急性心肌梗死 (AMI)的诊断、溶栓疗效的评价和室壁运动恢复的预测等方面的价值。方法　 13例AMI患者于溶栓前后分别进行IMCE检查 ,描划出时间 强度曲线 ,测量平台期的心肌显像最大强度A、曲线上升至A的平均斜率 β及A与 β之积在溶栓前后的变化。随访 3个月 ,判定IMCE各项指标预测左心室功能恢复的情况。结果　溶栓后梗死节段的A、β及A·β均较溶栓前差异有显著性意义 (P <0 .0 0 1)。相关分析显示 ,随访期室壁运动记分指数与溶栓后 A、β、A·β相关良好 (r=-0 .70 ,-0 .59和 -0 .66,P <0 .0 5) ,其中与 A 相关性最好。以 A =4分作为心肌再灌注的标准 ,对室壁运动的恢复具有较高的预测准确性。结论　利声显IMCE可实现AMI患者溶栓疗效的即刻评价 ,而且对室壁运动的恢复具有重要的预测价值     

多巴酚丁胺负荷超声心动图结合心肌灌注造影早期诊断冠心病的价值

目的 探讨大剂量多巴酚丁胺负荷超声心动图(DSE)结合心肌灌注造影(MCE)技术早期诊 断冠心病的价值。方法 对临床可疑冠心病的38例患者进行大剂量多巴酚丁胺负荷试验,分别在静息状态和试验终止的即刻实行MCE检查。并在静息状态及各级负荷状态下观察室壁运动(WM)情况;对每次MEC后各心肌节段灌注状态进行评估。大剂量DSE时,以冠状动脉造影为金标准比较WM目测法和心 肌灌注状态目测法诊断冠心病的敏感性和特异性。结果 DSE时,9例(24％)患者达到峰值负荷水平,22 例(58％)达到中级负荷水平。DSE终止时,通过心肌灌注状态目测法及WM目测法诊断有心肌缺血患者 的例数分别为24例(89％)及15例(52％)(P＜0.01)。同时,通过上述两组方法评估心肌缺血,并根据相应缺血心肌节段所对应冠脉分支准确判断病变血管的敏感性分别为71％及41％(P ＜0.01)。结论 大剂量DSE结合心肌灌注造影可以提高检出缺血心肌的敏感性,发现隐匿性心肌缺血,为临床诊断早期冠心 病患者提供了无创性新方法。     

利声显心肌声学造影在冠心病介入治疗中的应用

目的　探讨利声显经静脉心肌声学造影 (IMCE)在冠心病介入治疗的疗效评价及左心室功能恢复预测等方面的应用。方法　对 2 0例冠心病患者于介入治疗前后分别行IMCE检查 ,测量平台期的心肌显像最大强度A、曲线上升至A的平均斜率 β及A与 β之积在治疗前后的变化。随访 3个月 ,判定IMCE各项指标预测左室功能恢复的情况。结果　介入治疗后相关心肌节段的A、β及A·β均较介入前显著增加 (P <0 .0 0 1)。相关分析显示 ,随访期室壁运动记分指数与介入治疗后A、β、A·β相关良好 ( r =-0 .77,-0 .5 5 ,-0 .65 ,P <0 .0 0 1) ,其中与A相关性最好。以A =3分作为心肌再灌注的标准 ,对室壁运动的恢复具有较高的预测准确性。结论　利声显IMCE可实现冠心病患者介入治疗的疗效评价 ,而且对室壁运动的恢复具有重要的预测价值     

全心尖切面心肌背向散射积分参数评价心肌缺血

目的探讨全心尖切面心肌背向散射积分参数评价心肌缺血的可靠性.方法分析22例冠心病(CAD)患者和18例冠状动脉定量造影(QCA)正常患者的全心尖切面心肌所测左室16个节段背向散射积分参数,分别比较CAD组中室壁运动异常节段心肌、室壁运动正常节段心肌及对照组心肌的CVIB、CVIB%及AII%值.结果 CAD组中室壁运动异常节段心肌CVIB、CVIB%值均显著低于后二者,而AII%值则显著高于后二者.结论全心尖切面所测左室16个节段背向散射积分参数能够敏感、客观并比较全面地反映心肌缺血情况.     

心肌声学造影在冠状动脉旁路移植术中的临床应用

目的　探讨利声显经静脉心肌声学造影 (IMCE)在冠心病冠状动脉旁路移植术 (CABG)的疗效评价及左室功能恢复的预测等方面中的应用。方法　对 16例冠心病患者于 CABG前后分别行 IMCE检查 ,测量平台期的心肌显像最大强度 A、曲线上升至 A的平均斜率β及 A与β之积在手术前后的变化。随访 3个月 ,判定 IMCE各项指标预测左室功能恢复的情况。结果　手术后相关心肌节段的 A、β及 A·β均较术前显著增加 (P<0 .0 0 1)。相关分析显示 ,室壁运动记分指数 (wall molionscore index,WMSI)与 IMCE的三项测值 A、β及 A·β均有相关关系 ,其中以随访期 WMSI与术后 IMCE的 A值之间相关性为最佳 (r=- 0 .72 ,P<0 .0 0 1)。以术后 A=3分作为心肌再灌注的标准 ,对室壁运动的恢复具有较高的预测准确性。结论　利声显 IMCE提供了床旁无创评估 CABG疗效的新手段 ,且对室壁运动的恢复具有重要的预测价值     

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.