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     

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     

心肌声学造影评估心肌微血管血流储备的临床研究

目的　探讨利声显经静脉心肌声学造影 (IMCE)评价心肌微血管血流储备的可行性和临床应用价值。方法　选择 10例冠状动脉造影正常 (I组 )和 8例左前降支 (LAD)存在 5 0 %～ 70 %狭窄的患者 (Ⅱ组 ) ,分别在静息状态和双嘧达莫负荷试验后进行两次IMCE检查。分析递增触发时的心肌多普勒信号并描绘时间 强度曲线 ,测量平台期心肌显影强度A、曲线上升平均斜率 β及A·β乘积在负荷试验前后的变化 ,并测定相应的储备值。结果　静息状态下两组均呈均匀一致的正常心肌灌注 ,负荷试验后两组的 β及A·β均较负荷前增加 ,差异有显著意义 (P <0 .0 5 ) ;负荷前后两组的A储备值差异无显著性意义 (P >0 .0 5 ) ,而Ⅰ组的 β储备值及A·β储备值均显著高于Ⅱ组 (分别为 3 .0 6± 0 .95vs 1.5 2± 0 .3 7,3 .3 0± 1.0 4vs 1.48± 0 .42 ,均P <0 .0 0 5 ) ,提示Ⅱ组的心肌微血管血流储备降低。结论　IMCE可用于检测轻中度狭窄冠状动脉支配区域的微血管血流储备异常。     

利声显心肌声学造影在急性心肌梗死中的临床应用

目的 :探讨利声显心肌声学造影 (IMCE)在 AMI早期确诊及评价溶栓疗效中的价值。方法 :11例AMI患者溶栓治疗前后行 IMCE检查 ,分析利声显输注和递增触发时的心肌多普勒信号 ,并描绘时间 -强度曲线 ,测量平台期心肌显影强度 (A)、曲线上升平均斜率 (β)及 A·β乘积在治疗前后的变化。结果 :溶栓后 A、β及 A·β值均显著增加 (P<0 .0 5～ 0 .0 1) ,而溶栓失败者 A仍≤ 2分。结论 :IMCE为 AMI的诊断及床旁评价溶栓疗效提供了简便、安全和可靠的新途径     

经静脉心肌声学造影无创性评价冠状动脉旁路 移植术疗效的临床研究

目的 探讨利声显经静脉心肌声学造影（IMCE）在冠状动脉旁路移植术（CABG）疗效评价中的价值。方法 对12例患者于CABG前后行IMCE检查，分析利声显输注和递增触发时的心肌多普勒信号并描绘时间一强度曲线，测量平台期心肌层显影强度A，曲线上升平均斜率β以及A，β乘积的治疗前后的变化。结果 所有患者均成功行CABG术及IMCE检查，CABG术后A，β及A，β值均显著增加（P＜0．001），结论 IMCF为无创性评价CABG的疗效提供了简便，安全和可靠的新途径。     

利声显经静脉心肌声学造影评价冠心病再灌注治疗的价值

目的　探讨利声显经静脉心肌声学造影 (MCE)在冠心病再灌注治疗疗效评价中的价值。方法　在 9例行溶栓治疗 (Ⅰ组 )、10例行经皮冠脉成形术和冠脉内支架植入术 (Ⅱ组 )以及 6例行冠脉旁路移植术 (Ⅲ组 )共 2 5例冠心病患者中分别于治疗前后行MCE检查 ,分析利声显输注和递增触发时的心肌多普勒信号并描绘时间 强度曲线 ,测量平台期心肌显影强度A、曲线上升平均斜率 β以及A·β乘积在治疗前后的变化。 结果　Ⅰ组溶栓后A、β及A·β值均显著增加 ( P <0 .0 5～ 0 .0 1) ;Ⅱ组术后 β值显著增加 ( P <0 .0 5 ) ,但A及A·β乘积无明显改变 ;Ⅲ组术后 β及A·β乘积均显著增加 ( P <0 .0 5 ) ,但A值变化未达统计学意义。结论　MCE为评价冠心病再灌注治疗疗效提供了简便、安全和可靠的新途径。     

利声显心肌声学造影显像在冠脉搭桥术中的应用

目的　评价经静脉注射利声显心肌声学造影间隙显像在冠脉搭桥术中的应用价值。方法　用经静脉注射利声显心肌声学造影间隙显像,对25例临床诊断为陈旧性心肌梗死准备行冠脉搭桥术患者手术前后的心肌灌注和心脏功能进行分析。结果　术前灌注正常、减弱和无灌注的节段分别为22、57和13个。术后灌注正常、减弱和无灌注的节段分别为55、35和2个。造影记分指数从术前的0.74±0.08增加到术后的0.89±0.06,差别有极显著性意义（P<0.001）。92个与搭桥相关的节段中,术后59个（64%）功能改善。室壁运动记分指数从术前的1.50±0.27减少到术后1.24±0.20（P<0.001）。左室射血分数从0.49±0.05增加到0.55±0.04（P<0.001）。手术前后室壁运动记分指数和左室射血分数的变化程度与心肌声学造影检测为存活心肌的节段数高度相关（r=0.96,0.82,P均<0.001）;术后室壁运动记分指数和左室射血分数与术前心肌造影记分指数相关（r=-0.64,0.60,P均<0.05）。心肌声学造影对冠脉搭桥术后心脏节段功能恢复的预测敏感性和特异性分别为98%和36%。结论　经静脉注射利声显心肌声学造影不仅可用于评价冠脉搭桥术的效果,还可预测术后左室功能的恢复。     

心肌超声造影对急性心肌梗死冠状动脉内支架植入术后再灌注的评价

目的探讨经静脉心肌超声造影(IMCE)对急性心肌梗死患者行冠状动脉内支架植入(ISI)术后再灌注的评价.方法对24例急性心肌梗死患者于ISI术前后分别行IMCE检查,测量平台期心肌显像增大强度(A)、曲线上升平均斜率(β)及A与β之积在手术前后的变化.随访3个月,再次测量上述各项指标,评价心肌再灌注情况.结果手术后及随访期检测相关心肌节段的A、β及A·β均较术前显著增加(P＜0.01),其中术后β值的变化幅度最大,随访3个月后A值变化幅度增大,说明血管再通后先有灌注速度加快,再有灌注量增加.结论IMCE是床旁无创评估ISI疗效的新方法.     

超声背向散射技术研究慢性缺血性功能异常心肌跨壁异质性的临床意义

目的　利用超声背向散射 (IBS)技术研究慢性缺血性功能异常心肌在血管成功再灌注前后跨壁异质性的变化特征 ,探讨其临床应用价值。方法　分别在血管重建术前及术后 ,检测 5 8例慢性冠心病伴有左室壁节段功能障碍患者 (共 88个异常心肌节段 ,4 3个正常心肌节段 )相关心肌节段心内膜下层及心外膜下层心肌的 IBS周期变化幅度 (CVIB) ,计算跨壁梯度 (TGCV)和跨壁梯度指数(TGI) ,并在常规超声下测量相应心肌节段的室壁增厚率 (WT% )。结果　正常心肌 CVIB具有跨壁梯度 [TGCV:(1.2 2± 0 .4 6 ) d B,TGI:(2 0 .8± 6 .6 ) % ]。血管重建术前 ,存活心肌节段 TGCV、TGI减低并逆转为负值分别为 (- 0 .5 9± 0 .2 7) d B和 (- 16 .8± 8.5 ) % ;而非存活心肌节段 CVIB跨壁梯度基本消失 [TGCV:(- 0 .0 6 4± 0 .16 ) d B,TGI:(- 3.2 2± 6 .84 ) % ]。存活心肌节段的跨壁异质性 (|TGCV|、 |TGI|)明显小于正常心肌节段 (P<0 .0 0 1)、大于非存活心肌节段 (P<0 .0 0 1)。异常心肌节段的 |TGCV|、 |TGI|与血管重建术后 6～ 8周相应心肌节段的 WT%均呈正相关 (分别为 r=0 .6 35 ,P<0 .0 0 1和 r=0 .4 5 9,P<0 .0 1)。结论　利用 CVIB检测人体心肌的跨壁收缩异质性 ,可以评价慢性缺血性功能障碍心肌的收缩储备 ,对预测术     

多普勒组织成像技术对缺血心肌再灌注前后室壁运动的定量研究

目的　利用多普勒组织成像技术 (DTI)观察正常人及冠心病患者心肌运动的特点 ,并了解缺血心肌再灌注前后心肌运动改变情况。方法　 16例健康人及 18例冠心病患者均行DTI检测 ,冠心病患者再灌注后再行DTI ,比较手术前后DTI变化情况。结果　冠心病患者和健康人相比 ,收缩期峰值速度 (VS)明显降低 (室间隔心尖段除外 ) ,舒张早期峰值速度 (VE)也明显减低 (间壁心尖段及下壁心尖段除外 )。再灌注前后比较 ,运动恢复节段VS、VE 均明显提高。结论　DTI能定量分析缺血心肌再灌注前后室壁运动变化情况。     

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.