实时三维超声心动图测量左心室容积的实验研究

目的　探讨实时三维超声心动图 (RT 3DE)检测体外模拟左心室室壁瘤条件下的左心室容积的可行性与准确性。方法　使用RT 3DE系统采集 1 5个模拟左心室室壁瘤的橡胶水囊 (对称性 7个 ,非对称性 8个 )以及 1 0只犬离体心脏 ( 6只有左心室室壁瘤形成 ,4只对照 )的“金字塔”形数据库 ,结合容积分析软件 ,分别用 2、4、8、1 6平面法勾画水囊及左心室内膜面 ,计算水囊与左心室容积。同时用二维超声Simpson法测量水囊与左心室容积 ;以注水法测量水囊及左心室实际容积作为参照 ,分别将不同平面法的RT 3DE容积测量值、2DE测值与之相比较。结果　在对称性橡胶水囊容积测量 ,RT 3DE各平面法与实际值均呈正相关 (r =0 .795～ 0 .994) ;2DE亦与实际值正相关 (r =0 .71 5 ) ;RT 3DE、2DE与实际值差异无显著性意义 (P >0 .0 5 )。在非对称性橡胶水囊容积测量 ,RT 3DE各平面法测量的左心室容积与实际值均呈正相关 (r =0 .775～ 0 .988) ,两者差异无显著性意义 (P >0 .0 5 ) ;2DE与实际值r =0 .5 92 ,两者差异有显著性意义 (P <0 .0 5 )。离体犬左心室室壁瘤组RT 3DE各平面法测量的左心室容积与实际值均呈正相关 (r =0 .765～ 0 .91 4) ,两者差异无显著性意义 (P >0 .0 5 ) ;2DE与实际值亦呈正相关 (r =0 .61 5 ) ,两者差     

实时三平面超声心动图评价心肌梗死患者左心室总体收缩功能的研究

目的 探讨实时三平面超声心动图(RT-3PE)测量心肌梗死患者左心室总体收缩功能的可行性、准确性和重复性.方法 同期应用RT-3PE和二维超声心动图(2DE)双平面Simpson法测量30例心肌梗死患者左心室舒张末期容积(LVEDV)、左心室收缩末期容积(LVESV)和左心室射血分数(LVEF),并与单光子发射计算机断层成像术(SPECT)测值进行对比研究,同期由同一和不同的检查者应用RT-3PE进行重复测量并将测量结果进行比较.结果 (1)RT-3PE和2DE Simpson法所测LVEDV分别为(86.67±37.64)、(86.43±38.25)ml,LVESV分别为(42.13±37.42)、(41.06±32.47)ml,SPECT测量的LVEDV和LVESV分别为(108.70±66.27)、(55.90±61.68)ml,RT-3PE和2DE Simpson法测得LVEDV和LVESV分别与SPECT比较差异有统计学意义(t=3.63、2.76、3.37、2.54,P均＜0.01或0.05);3种方法所测LVEF值之间差异无统计学意义(P＞0.05).(2)RT-3PE测得LVEDV、LVESV和LVEF与SPECT相应的测量值密切相关(r=0.943、0.965、0.816,P均＜0.01);2DE Simpson法测得LVEDV、LVESV和LVEF与SPECT相应的测量值相关性较好(r=0.896、0.957、0.721,P均＜0.01).Altman-Bland一致性分析显示RT-3PE所测左心室容积和收缩功能与SPECT测值的一致性高于2DE Simpson法.(3)同一和不同的检查者采用RT-3PE重复测量结果之间差异无统计学意义(P＞0.05),且有良好的相关性,同一检查者采用RT-3PE两次测量LVEDV、LVESV和LVEF的相关性良好(r=0.968、0.984、0.883,P均＜0.01);不同检查者采用RT-3PE测量LVEDV、LVESV和LVEF的相关性也很好(r=0.948、0.970、0.899,P均＜0.01).结论 RT-3PE是一种能够快速、准确测量心肌梗死患者左心室总体收缩功能的影像技术.     

实时三维超声心动图结合声学造影测量犬左室容积

目的探讨实时三维超声心动图(RT3DE)结合声学造影测量左室容积的准确性.方法应用RT3DE诊断仪分别测量15只犬在无造影、造影状态下的左室舒张、收缩末期容积(LVEDV、LVESV)和每搏量(SV).对RT3DE和二维所测LVEDV、SV值,分别与左室实际值、Doppler频谱法SV测值进行对照分析.结果 RT3DE造影法相关性高于单纯RT3DE、二维Simpson法和面积长度法(r分别为0.934、0.920、0.846和0.768).结论实时三维超声心动图结合声学造影能更准确地定量测量左室容积.     

实时三维超声心动图定量评价左室容积及其收缩功能的研究

目的初步探讨实时三维超声心动图(RT-3DE)测量左心室容积及其收缩功能的可行性、准确性及重复性.方法 38例研究对象分成三组A组8例,系陈旧性心肌梗死伴左室多壁段收缩活动异常者,其中3例并有室壁瘤;B组10例,系左室明显增大且整体收缩活动普遍减弱者;C组20例,系正常对照.使用Philips Sonos 7500 RT-3DE系统采集三维图像,利用TomTec 4D Cardio-view RT 1.0 软件,采用心尖长轴等角度旋转多平面法(2、4、8、16平面法),测量左室舒张末期容积(LVEDV)和收缩末期容积(LVESV),并计算出左室射血分数(LVEF);并与二维超声心动图(2DE)改良Simpson氏法和M-型超声心动图 Teichholz 法测值比较.结果 1.三组研究对象均显示Tom Tec2平面法的LVEDV偏小,与4、8、16平面法比较差异均存在显著性意义(P＜0.001);4、8、16平面法的测值间差异则均无显著性意义(P＞0.05);2.A、B两组RT-3DE与2DE的LVEF测值差异均无显著性意义,且有很好的相关性(r=0.973,P＜0.001),但2DE测得的LVEDV、LVESV均偏低;A、B两组RT-3DE与M-型超声上述各项测值差异均存在显著性意义(P＜0.05),M-型测得的左室容积偏大,EF存在高估或低估现象;C组显示3种方法之间各项测值差异均无显著性意义,RT-3DE与2DE的LVEF较M-型超声有更好的相关性(r分别为0.920,0.875);4.Tom Tec 4平面法的LVEDV、LVESV、LVEF 同一观察者两次测值间均无显著差异,且有很好的相关性(r分别为0.962、0.920、0.916,P均<0.001);平均测量相对误差分别为6.54%、1.16%、3.21%.结论实时三维超声心动图作为一种无创的新技术通过全容积成像方式可以快捷地显示心脏立体结构,检测左室容积及其收缩功能方法准确可行,测量取Tom Tec 4平面法比较恰当,适合临床推广应用,尤其在节段性室壁运动异常及心室扩大伴整体收缩功能减弱时更显示其优点.     

实时三维超声心动图定量评价左心室容积及射血分数

目的 探讨实时三维超声心动图（RT-3DE）定量评价左心室容积及射血分数的可行性及准确性。 方法 以心脏核磁共振（cMRI）为参考标准，应用RT-3DE测量31例健康志愿者左心室舒张末期容积（LVEDV）、收缩末期容积（LVESV）、每搏量（SV）及射血分数（EF）。 结果 （1）30例志愿者获得了清晰内膜边界的三维图像和CMRI图像，RT-3DE图像采集及分析时间明显短于CMRI；（2）RT-3DE测量所得LVEDV、LVESV、SV、EF与CMRI具有良好的相关性，r分别为0．946、0．939、0．950、0．947（P均〈0．001），LVEDV、LVESV、SV测值较CMRI偏小（P均〈0．001），EF测值二者间差异无显著性意义（P〉0．05）；（3）RT-3DE测值观察者内及观察者间均具有良好的一致性，r值0．903～0．947。 结论 RT-3DE是一种定量评价左心室功能的准确、可靠的新技术，必将在心血管疾病诊断、治疗及随访中发挥作用。     

实时三维超声心动图测量急性心肌梗死左心室容积与射血分数最佳切面的研究

目的探讨实时三维超声心动图(RT-3DE)测量急性心肌梗死左心室容积与射血分数的最佳切面。方法对14条杂种犬急性心肌梗死动物模型进行二维(2DE)和RT-3DE检查,分别应用2DE和RT-3DE的2-平面法、4-平面法和8-平面法测量左心室舒张末期容积(EDV)、收缩末期容积(ESV)、每搏输出量(SV)和射血分数(EF),用注射盐水法测量离体心脏左心室容积作为参照容积,采用Bland和Altman方法进行一致性分析。结果2DE和RT-3DE的2-平面法、4-平面法测量的EDV、ESV、SV与RT-3DE8-平面法的测量结果高度相关(r=0.84～0.99),2DE、RT-3DE2-平面法测值显著低于RT-3DE8-平面法测值(P<0.01),而RT-3DE4-平面法与8-平面法测值间差异无统计学意义(P>0.05)。2DE、RT-3DE2-平面法及4-平面法测量的EF与RT-3DE8-平面法测量结果高度相关(r=0.82～0.98),与RT-3DE8-平面法测量的EF值间差异无统计学意义(P>0.05)。2DE、RT-3DE2-平面法、4-平面法测量的EDV与参照容积测量结果高度相关(r=0.84,0.92,0.94,0.97),RT-3DE4-平面法、8-平面法的EDV测值与参照容积间差异无统计学意义(P>0.05),但2DE、RT-3DE2-平面法的EDV测值显著低估参照容积(P<0.01)。RT-3DE4-平面法、8-平面法测量的EDV与参照容积间的一致性明显高于2DE、RT-3DE2-平面法。RT-3DE4-平面法测量的可重复性优于2DE。结论RT-3DE在测量急性心肌梗死左心室容积和射血分数中具有较高的准确性和可重复性,其中RT-3DE4-平面法是既准确又省时的最佳测量切面。     

实时三维超声心动图测量室壁瘤患者左心室容积和收缩功能的可行性研究

目的探讨实时三维超声心动图(RT-3DE)检测室壁瘤患者左心室容积和收缩功能的可行性和准确性。方法应用RT-3DE及左心室造影分别测量21例室壁瘤患者的左心室舒张末容积(LVEDV)、收缩末容积(LVESV)和射血分数(LVEF),将RT-3DE测值与左心室造影测值相比较。结果 RT-3DE能显示室壁瘤患者左心室的整体形态,其测量的LVEDV、LVESV较左心室造影测值偏小,差异有统计学意义(P0.05),而LVEF差异无统计学意义(P0.05)。但两种方法测量LVEDV、LVESV、LVEF的相关性r值分别为0.76、0.86、0.67,相关性较好。结论 RT-3DE能够准确测量室壁瘤患者左心室容积和收缩功能。     

实时三维超声成像技术测量右心室容积的方法学研究

目的 评价实时三维超声心动图(RT—3DE)技术测量右心室容积的可行性与准确性，并探讨最佳测量平面数。方法 使用RT—3DE系统采集22例正常成人的右室“金字塔”形三维数据库，结合其容积分析软件，脱机采用心尖长轴多平面法，分别测量右室的舒张末期容积(RVEDV)、收缩末期容积(RVESV)，并由二者之差计算右室每搏量(RVSV)，同时在二维超声心动图上计算左室每搏量(LVSV)。结果 RT—3DE上2平面、4平面、8平面以及16平面法测得的RVSV均与LVSV相关性好(r分别为0．73，0．69，0．62，0．66，P＜0．025-0．0025)；2平面法测得的RVEDV较4平面、8平面以及16平面法测值差异有显著性意义(P＜0．0001）；4平面法与8平面法测值差异有显著性意义(P＜0．05)；8平面法与16平面法测值间差异则无显著性意义(P＞0．05)。结论 应用RT—3DE技术确定右室容积准确可靠、重复性高，提示临床上使用心尖8平面法测量右室容积比较理想。     

实时三维超声心动图在正常人左心室容积及其收缩功能检测中的应用

目的 探讨实时三维超声心动图(RT—3DE)测量左心室容积及其收缩功能的方法及可行性。方法 健康志愿者37例，应用矩阵换能器和实时三维成像软件采集三维图像，利用TomTec4D Cardio—View RTl．0软件测量左室舒张末期容积(LVEDV)和收缩末期容积(LVESV)，进而计算出左室射血分数(LVEF)。同时应用二维超声心动图(2DE)双平面Simpson′s法和M型超声心动固Teichho1z法分别测量LVEF值。结果 通过RT—3DE重建的左室三维图像结构完整，采集时间短，内膜清楚可辨；3种方法的各项测值之间差异无显著性意义(P＞0．05)。RT—3DE测定的LVEF值与2DE测值有很好的相关性(r＝0．9342，P＜0．001)，与M型超声相比虽有相关性，但不如前二者显著(r＝0．8695，P＜0．05)。结论 实时三维超声心动图作为一种无创的新技术通过全容积成像方式可以快捷地从各方位清晰显示心脏立体结构，检测左室容积及其收缩功能，方法准确可行，有利于临床推广应用。     

实时三平面超声心动图评价扩张型心肌病、冠心病患者左室容积及收缩功能

目的：初步探讨实时三平面超声心动图（RT-3PE）评价扩张型心肌病、冠心病患者左室容积及收缩功能的可行性。方法：RT-3PE分别测量20例正常人、16例扩张型心肌病和23例心肌梗死患者的左室舒张末期容积（LVEDV）和收缩末期容积（LVEsV），计算出左室射血分数（LVEF）；并分别与二维超声心动图（2DE）的双平面Simpson法和M型超声心动图的Teichholz法测值进行比较。结果：①正常人中LVEDV、LVESV及EF，RT-3PE、2DE的双平面Simpson法和M型超声心动图的Telchholz法的各项测值之间无显著性差异（P〉0．05），RT-3PE与2DE所测LVEF较M型超声心动图有更好的相关性（r分别为0．91，0．85，P〈O．05）。②在扩张型心肌病和心肌梗死患者中，RT-3PE与2DE的双平面Simp—son法检测LVEF均具有很好的相关性（r分别为0．99，0．98，P〈0．05），两者之间无显著性差异（P〉0．05），但是2DE的双平面Simpson法所测的LVEDV、LVESV均明显低于RT-3PE测值，两者之间有显著性差异（P〈0．05）。而M型测得的LVEDV、LVESV偏大，LVEF存在高估或低估现象。③RT-3PE所测的LVEDV、LVESV及LVEF，同一观察者两次测值间均无显著性差异（P〉O．05），且有良好的相关性（r分别为0．98．0．97，0．88，P〈O．05）。结论：RT-3PE能够快速、无创地测量心室容积及收缩功能，为临床评价节段性室壁运动异常及心腔扩大的心室功能提供了一种实用、简便的方法。     

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.