应用门控心肌显像定量分析室壁局部运动对心功能的影响

目的 利用定量门控^99mTc-MIBI心肌显像评价左心室室壁各节段运动对左心功能的影响。 方法 对768例患者进行门控^99mTc-MIBI心肌显像,采用QGSPECT程序定量获得20节段的局部室壁运动(WM)及左心室射血分数(LVEF)值。分析LVEF与心室各节段WM的关系。 结果 所得4个公共因子分别代表不同的节段信息,F₁反映了心尖、侧壁的近心尖和中段、前壁、下壁和下间隔的近心尖的信息。F₂反映了前壁和下间隔的中段、整个前间隔的信息。F₃反映了前壁和下侧壁的基底段的信息。F₄反映了下壁的中段和基底段及下间隔基底段的信息。利用多元线性回归分析的方法得出其对LVEF影响的大小顺序为F₁＞F₃＞F₂＞F₄(标准回归系数分别为0.633、0.471、0.415、0.169,P＜0.001)。 结论 应用定量门控心肌显像获得的WM与LVEF有显著的相关性,影响最大的包括心尖、侧壁的近心尖和中段、前壁、下壁和下间隔的近心尖。     

应用三维斑点追踪技术评价2型糖尿病患者左心室收缩功能

目的 应用三维斑点追踪技术(3D-STE)检测2型糖尿病(T2DM)患者左心室收缩功能。 方法 收集T2DM患者55例,分为单纯糖尿病组31例和糖尿病合并微血管病变组24例;另选择健康人31名作为对照组。常规采集各切面图像和左心室全容积图像,将全容积图像输入TomTec 4D LV analysis软件,计算16节段心肌三维应变(3DS)、纵向应变(LS)、圆周应变(CS)值,并与左心室射血分数(LVEF)行相关性分析。 结果 与对照组比较,单纯糖尿病组和糖尿病合并微血管病变组中间部和心尖部的前间隔、侧壁,基底部和中间部后壁,心尖部下壁的3DS均显著减低(P均<0.05);中间部前间隔、前壁、后壁,心尖部后间隔 LS均减低(P均<0.05);基底部、中间部及心尖部侧壁,基底部和中间部后壁CS明显减低(P均<0.05);3DS与LVEF呈正相关(r=0.75,P<0.01)。 结论 3D-STE对评价糖尿病左心室动力学具有较高的应用价值;3DS可较CS、LS更全面、客观地评价糖尿病心肌病左心室心肌收缩功能受损情况。     

速度向量成像技术评价正常人左心室壁形变分布特征

目的 应用速度向量成像(VVI)技术初步评价正常人左心室壁形变特征。 方法 采集并动态存储47名健康志愿者胸骨旁系列左心室短轴观及心尖系列左心室长轴观连续3个心动周期二维灰阶图像,运用VVI软件显示左心室壁各节段应变曲线,并观察各曲线形态特征,对照同步记录心电图测量左心室壁各节段各应变分量收缩期峰值。 结果 正常人左心室壁各应变分量在左心室不同水平间比较差异均无统计学意义(P均＞0.05)。正常人左心室壁各应变分 量收缩期峰值比较径向＞周向＞纵向,且差异有统计学意义(P均＜0.05)。左心室游离壁纵向及周向收缩期峰值应变心内膜测值均显著大于心外膜测值(P均＜0.05);室间隔纵向及周向收缩期峰值应变显示右心室面测值大于左心室面测值,但差异无统计学意义(P＞0.05)。 结论 正常人左心室壁收缩期峰值应变分布具有一定的特征,认识这些特征有助于判断左心室壁异常形变。     

超声斑点追踪技术评价手足口病患儿左心室局部收缩功能

目的 应用二维斑点追踪技术评价重症手足口病患儿左心室局部收缩功能。 方法 收集危重症手足口病患儿28例(重症组)、轻症手足口病患儿30例(轻症组)、同期年龄及性别匹配体检儿童30名(对照组)。应用二维斑点追踪技术检测重症组、轻症组及对照组左心室17个节段的收缩期长轴峰值应变、双平面Simpson法检测左心室射血分数,比较重症组、轻症组与对照组临床及血清学检查结果。 结果 重症组心率增快,白细胞总数、血糖及肌酸磷酸激酶心肌同工酶升高,左心室射血分数减低,与轻症组及对照组比较差异有统计学意义(P＜0.05);轻症组仅见下壁基底段及中间段收缩期峰值应变减低,与对照组比较差异有统计学意义(P＜0.05);重症组左心室后壁基底段及中间段、侧壁中间段收缩期峰值应变减低,与轻症组及对照组比较差异有统计学意义(P＜0.05);侧壁基底段收缩期峰值应变减低,与轻症组及对照组比较差异有统计学意义(P＜0.01);侧壁心尖段收缩期峰值应变减低,与对照组比较差异有统计学意义(P＜0.05)。 结论 重症手足口病患儿存在明显局部及整体收缩功能减低。轻症手足口病患儿尽管整体收缩功能正常,但可见个别节段局部收缩功能异常。超声斑点追踪技术可检测左心室局部收缩功能,可为轻症患儿的心脏受累的早期诊断及重症手足口病患儿病情进展和预后评价提供帮助。     

三维斑点追踪成像评价2型糖尿病患者左心室应变

目的 应用三维斑点追踪技术评价2型糖尿病(DM)患者左心室应变。方法 对30例2型DM患者(DM组)及30名健康志愿者(对照组)行三维斑点追踪成像,比较两组左心室整体及各节段应变。结果 DM组左心室收缩期整体应变(GS)、整体环向应变(GCS)、整体径向应变(GRS)及整体纵向应变(GLS)均低于对照组(t=2.18、3.27、2.05、3.76,P均<0.05)。DM组左心室前壁及侧壁环向收缩期峰值应变均低于对照组(P均<0.05);前壁基底段、中间段及侧壁径向收缩期峰值应变均低于对照组(P均<0.05);前间隔基底段、前壁基底段和中间段、侧壁中间段和心尖段、下壁心尖段纵向收缩期峰值应变均低于对照组(P均<0.05)。DM组基底段径向及纵向收缩期峰值应变均低于心尖段,中间段纵向收缩期峰值应变低于心尖段(P均<0.05)。对照组基底段环向、径向及纵向收缩期峰值应变均低于心尖段,中间段纵向收缩期峰值应变低于心尖段(P均<0.05)。结论 三维斑点追踪技术可用以评价2型DM左心室整体及节段收缩功能的早期改变。     

不同起搏模式对左心室功能及左心室短轴应变的影响

目的 探讨不同心脏起搏模式对具有正常房室传导顺序并植入双腔频率应答起搏器（即DDDR起搏器）的病态窦房结综合征（SSS）患者左心室功能和左心室短轴应变的影响。方法 纳入具有正常房室传导顺序并植入DDDR起搏器的SSS患者45例,对每例患者随机进行心房起搏心室起搏（APVP）、心房起搏心室感知（APVS）和心房感知心室感知（ASVS）模式起搏各30 min,通过超声心动图技术获取患者在3种模式下左心室功能和左室短轴应变参数。结果 3种起搏模式中,ASVS与APVS起搏模式下E/E'低于APVP起搏模式,LVEF和SV高于APVP起搏模式（P<0.05）。收缩期峰值径向应变：ASVS起搏模式下除基底段前间壁外,余基底段各节段及中间段各节段均显著高于APVP起搏模式（P均<0.05）,APVS起搏模式下基底段侧壁、后壁、下壁及中间段各节段均显著高于APVP起搏模式（P均<0.05）。ASVS起搏模式下除基底段前间壁和中间段前壁和下壁外,余基底与中间段各节段均高于APVS起搏模式（P均<0.05）。收缩期峰值周向应变：ASVS起搏模式下基底段后壁和下壁和中间段侧壁高于APVP起搏模式,APVS起搏模式下中间段下壁和后间壁、心尖段后壁和下壁高于APVP起搏模式（P均<0.05）。结论 ASVS和APVS起搏模式下能较好地保存心肌收缩能力和维持有效的心排出量。     

实时三维斑点追踪显像技术评价心肌缺血患者左心室局部功能

目的 应用实时三维斑点追踪显像(3D-STI)技术评价冠状动脉左前降支(LAD)不同狭窄程度缺血患者左心室心肌局部应变变化。方法 根据冠状动脉造影(CAG)结果将138例临床疑诊冠心病患者分为对照组(34例)和狭窄组(104例),另将狭窄组分为轻度狭窄亚组(A亚组,n=34)、中度狭窄亚组(B亚组,n=36)和重度狭窄亚组(C亚组,n=34)。测量LAD供血区域心肌的应变指标:峰值径向应变(PLS)、峰值面积应变(PAS)、应变显像舒张指数(SI-DI),分析2D-STI及3D-STI测值的相关性。结果 对照组3D-STI的PLS较2D-STI值偏低(P<0.05),相关性良好(r值:0.58~0.76)。A亚组PAS与对照组相比差异无统计学意义(P>0.05)。与对照组比较,C亚组全部节段及B亚组前壁中间段及心尖段、前间隔中间段及前间隔心尖段的PAS值减低(P<0.05),C亚组全部节段及B亚组前壁基底段及心尖段、前间隔中间段及前间隔心尖段的SI-DI值减低(P<0.05);与B亚组比较,C亚组的前壁中间段及心尖段的PAS值减低(P<0.05),前壁中间段及心尖段和前间隔心尖段的SI-DI值减低(P<0.05)。结论 3D-STI可有效评估心肌缺血患者左心室局部心肌纤维早期形变特征。     

二维应变超声心动图评价乳腺癌患者表阿霉素化疗后左心室收缩功能

目的 探讨二维应变超声心动图在评价乳腺癌术后患者表阿霉素化疗左心室心内膜下心肌局部收缩功能的价值.方法 116例乳腺癌患者分为3组:A组38例,给予表阿霉素总剂量120～340 mg/m2;B组42例,给予表阿霉素总剂量≥360 mg/m2;C组36例,为尚未进行化疗患者,作为对照组.对三组患者分别进行常规超声测量并记录左心室心尖长轴切面、心尖两腔切面及心尖四腔切面的高帧频二维图像,应用二维应变超声分析软件测量左心室心尖位心内膜下心肌收缩期峰值应变.结果 A、B、C三组常规超声心动图各参数之间差异无统计学意义(P>0.05).A组与C组相比,除前间隔基底段、侧壁心尖段、后壁及下壁中间段、心尖段和后间隔心尖段外,左心室心尖位各节段心内膜下心肌峰值收缩期应变出现减低,差异有统计学意义(P<0.05);B组各节段心内膜下心肌峰值收缩期应变较C组出现明显减低,差异有统计学意义(P<0.05),与A组相比除前间隔基底段、中间段,后壁基底段,下壁基底段、中间段、心尖段及后间隔中间段外,应变在部分节段有所减低,差异有统计学意义(P<0.05).结论 二维应变超声心动图能够早期监测表阿霉素化疗后左心室心内膜下心肌局部收缩功能.     

超声二维应变成像观察冠心病患者缺血心肌收缩功能异常

目的 应用超声二维应变成像技术检测冠心病患者左心室缺血心肌在不同方向上收缩运动的变化特点。方法 收集接受冠状动脉造影检查患者83例,其中52例造影证实为冠心病(冠心病组),31例造影未见异常(对照组)。超声采集左心室短轴及心尖长轴切面的高频二维动态图像,应用二维应变分析软件测量左心室各节段心肌的收缩期纵向应变(LS)、径向应变(RS)、圆周应变(CS)和旋转角度(RA)。结果 二维应变技术对冠心病组缺血心肌的测量成功率为95.26%(402/422);缺血心肌的LS、RS显著低于对照组正常心肌(P＜0.05);除乳头肌水平前壁及后壁RA外,两组心肌CS、RA的差异无统计学意义(P＞0.05)。结论 二维应变技术所测LS、RS可敏感反映缺血所致局部心肌收缩功能异常;而CS、RA对于观察缺血心肌收缩功能损害不够敏感。     

二维斑点追踪分析肥厚型心肌病患者左心室前壁面积应变

目的 运用二维斑点追踪成像(STI)技术观察肥厚型心肌病(HCM)患者左心室前壁额断面心肌的面积应变。方法 收集25例肥厚型心肌病患者(HCM组)及25名健康志愿者(对照组),应用STI技术在左心室前壁心肌额断面采集25个ROI的面积应变,获得收缩期应变(ε)、收缩期应变率(SRS),舒张早期应变率(SRE)、舒张晚期应变率(SRA);比较两组的差异,并分析其与各左心室功能参数的相关性。结果 HCM组ε、SRS及SRE均低于对照组,而SRA高于对照组(P均<0.01);ε、SRS、SRE、SRA与左心室相对室壁厚度(RWT)、左心室质量指数(LVMI)呈线性负相关关系(P均<0.01)。结论 STI技术能够用于观察左心室前壁额断面心肌的面积应变,检出HCM患者的左心室局部心肌功能异常。     

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.     

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.     

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.