超声造影评价兔肾皮质血流灌注

目的 探讨超声造影评价兔肾皮质血流灌注状态的价值.方法 通过结扎肾动脉建立不同程度家兔肾皮质血流减少的模型.经耳缘静脉团注SonoVue(0.05 ml/kg体质量)进行肾灌注超声造影,观察并采集注射造影剂后0～3 min的动态图像,通过时间-强度曲线(TIC)软件分别计算肾动脉结扎前后肾皮质TIC的加速时间(AT)、峰值背向散射强度(A)、峰值减半时间(T)、峰值基础视频强度差(PBD)、TIC斜率(β)以及A·β值,并对以上指标进行t检验及相关分析. 结果 实时观察发现肾动脉结扎前,肾皮质表现为快速明显强化,增强顺序为各级肾动脉-皮质-锥体.结扎后AT明显延长(P<0.001),A显著减小(P<0.001), T明显缩短(P<0.001), PBD明显减低(P<0.001),β明显下降(P<0.002), A·β值显著降低(P<0.001).肾动脉狭窄程度与AT、PBD及A·β呈明显的相关;肾动脉狭窄率在31%～69%之间组与70%～93%之间组比较,后者较前者AT延长(P<0.001),A减小(P<0.029), PBD减低(P<0.001), A·β值降低(P<0.02). 结论超声造影剂和造影专用成像技术可灵敏地反映肾皮质微小血管的血流变化,在评价肾皮质的血流灌注状态方面有很高的应用价值.     

移植肾肾动脉狭窄的超声造影定量研究

目的 探讨超声造影定量分析诊断移植肾肾动脉狭窄（TRAS）的临床价值.方法 对8例彩色多普勒发现的TRAS（经DSA确诊）患者行移植肾超声造影定量分析,将其开始增强时间（BT）、达峰时间（PT）、上升支斜率（BPAS）、降支减半时间（HT）、峰值强度（PI）及曲线下面积（AUC）与20例正常移植肾比较.结果 TRAS组移植肾皮质增强程度弱于正常组;BT（P＜0.005）、PT（P＜0.001）大于正常组,BPAS、HT、PI、AUC（P均＜0.001）小于正常组（P＜0.001）.结论 移植肾超声造影定量分析是诊断TRAS的有效手段,具有广阔的临床应用前景.     

实时灰阶超声造影评价肾动脉狭窄血流灌注的实验研究

目的探讨兔肾动脉狭窄模型的超声造影肾脏血流灌注模式。方法对10只实验兔递进性钳夹左肾动脉主干,钳夹程度分四级:0级-正常;Ⅰ级-钳夹动脉主干1/3;Ⅱ级-钳夹动脉主干2/3;Ⅲ级-完全钳夹。应用实时超声造影匹配成像技术行超声造影检查,动态观察各钳夹级别狭窄侧肾脏血流灌注。对各钳夹级别肾脏皮质及段间动脉部位进行量化分析,提供以下指标:曲线下面积、峰值强度、开始增强时间、曲线上升斜率。分析上述指标在不同程度肾动脉狭窄模型中的变化规律。结果①肾脏血流灌注增强模式:肾段间动脉、叶间动脉、肾皮质、肾髓质依次增强。随钳夹程度递进,肾脏开始增强时间逐渐延迟,增强程度逐渐减弱。肾动脉完全闭塞时,注射造影剂前后肾脏回声无明显改变。②超声造影时间-强度定量分析:随钳夹级别的递进,皮质和段间动脉取样,开始增强时间逐渐延迟,曲线下面积、峰值强度呈递减趋势。曲线上升斜率Ⅱ级组低于0、Ⅰ级组,0级组与Ⅰ级组无差异。结论超声造影增强模式对筛查肾动脉狭窄有一定价值;超声造影定量分析有助于评价不同程度肾动脉狭窄时缺血肾血流灌注。     

超声造影诊断肾动脉狭窄的临床研究超声造影诊断肾动脉狭窄的临床研究超声造影诊断肾动脉狭窄的临床研究超声造影诊断肾动脉狭窄的临床研究

目的 探讨超声造影对肾动脉狭窄的诊断价值.方法 对临床疑有肾动脉狭窄的9例患者共17条肾动脉（1例患者一侧肾切除）行经静脉超声造影检查,超声造影前均先行常规超声检查,根据彩色多普勒血流信号、肾动脉峰值流速、肾动脉与肾动脉开口处腹主动脉的峰值流速比值、肾内叶间动脉血流加速时间、收缩早期加速度判断肾动脉是否存在狭窄,并与血管造影结果对比.结果 静脉注射超声造影剂8～15 s后肾动脉显影并达到最大强度,增强平均时间为（530±32）s.超声造影后有16条肾动脉显示,均观察到彩色血流信号增强,超声造影显示8条肾动脉狭窄,其中1条肾动脉造影后狭窄不明确,血管造影后确诊为轻度狭窄;不显影的1条被证实为闭塞.以血管造影为标准,超声造影诊断肾动脉狭窄与血管造影的吻合系数Kappa=0.882,P＜0.01;常规超声诊断肾动脉狭窄与血管造影的吻合系数Kappa=0.414,P＜0.05.结论 超声造影有助于提高肾动脉狭窄的血流显示,在诊断肾动脉狭窄方面,与常规超声相比,超声造影与血管造影结果显示出更好的一致性.     

兔肾血液微循环对高分子微泡稳定性的影响研究

目的探讨兔肾微循环对高分子微泡超声造影剂体内存留时间的影响。方法采用mPEG-PLLA为包膜材料制备包裹惰性气体的高分子微泡,超声造影分析软件比较肾动脉、肾静脉超声造影时间-强度曲线的峰值降半时间MTT、峰值强度PI、曲线下面积AUC等参数。结果高分子微泡兔肾动脉超声造影的MTT比肾静脉短,而峰值强度PI则明显高于肾静脉,AUC亦大于肾静脉,但差异无统计学意义(P0.05)。结论兔肾血液微循环不是影响高分子微泡稳定性与体内存留时间的主要因素。     

团注超声造影剂定量测定肾组织局部血流灌注的实验研究

目的：以超声造影剂ＦＸ５３０作为指示剂,以视频强度的变化作为指示指标,经外周静脉团注ＦＸ５３０,根据相关数学模型确定定量测定肾皮质血流灌注量的方法。方法：１）建立肾动脉狭窄模型,对不同程度的狭窄进行超声造影实验,并以组织和 仪测定肾皮质部位在各个程度的实际血流量;（２）根据指示剂稀释原理测定组织的单位容积内所含血管管腔内的血流容积比例与造影剂通过该单位容积组织的平均渡越时间,计算组织血流灌注量;３     

实时灰阶谐波超声造影诊断肾动脉狭窄的初步研究

目的评价实时灰阶谐波超声造影诊断肾动脉狭窄的临床价值。方法肾动脉狭窄患者16例，包括4例肾动脉支架置入术后者。超声造影剂使用SonoVue。所有患者均接受彩色多普勒超声与谐波造影两种检查方法。诊断结果分3级：①不能得到诊断结果；②可疑诊断；③诊断明确。检查结果与数字减影血管造影术、CT、MRI等结果相对照。结果彩色多普勒超声明确诊断的有8例（50．0％），可疑诊断5例（31．3％），不能得到诊断结果3例（18．7％）。结合谐波造影检查后明确诊断13例（81．3％），可疑诊断2例（12．5％），不能得到诊断结果1例（6．2％）。常规彩色多普勒超声诊断的敏感性63．6％（7／11），特异性40．0％（2／5），准确性56．3％（9／16）；谐波造影诊断的敏感性83．3％（10／12），特异性100％（4／4），准确性87．5％（14／16）。结论谐波造影能够更直观地显示血管管壁与管腔的边界，进而可直观地反映流道的变化，有助于肾动脉狭窄的诊断。     

彩色多普勒超声在肾动脉狭窄诊断中的应用

目的评价彩色多普勒超声对肾动脉狭窄（ARAS）的诊断指标及准确性。方法 1999年10月2008年12月对患有高血压病的58例共113根肾动脉进行彩色多普勒超声检查。每例患者均测量肾动脉峰值流速（PSV）与肾内段动脉的阻力指数及肾脏长轴。在双盲条件下,以患者肾动脉造影、MRI血管造影及CT血管造影为标准,评价彩色多普勒超声诊断ARAS的诊断指标及准确性。结果彩色多普勒超声诊断肾动脉狭窄的敏感性为60%,特异性为83%,阳性预测值为83%,阴性预测值为61%。患侧肾长轴小于健侧肾长轴,患侧肾峰值流速高于健侧肾峰值流速,患侧肾阻力指数低于健侧肾阻力指数。结论肾动脉彩色多普勒超声对于肾动脉狭窄初筛诊断以及评价肾动脉狭窄介入治疗后的近、远期疗效,是一种简便可靠的无创检查手段。     

超声造影彩色显像评估肾血流灌注的实验研究

目的评价超声造影彩色显像评估肾实质血流灌注的价值。方法20只兔~＇t-N静脉注射超声造影剂。造影前后用二维、彩色多普勒能量显像和彩色多普勒血流显像连续采集肾增强图像。定量分析测定二维及彩色增强显像的视频密度和彩色面积。得到二维显像和彩色谐波能量显像的时间一强度曲线。结果造影后彩色谐波能量图的视频密度为199．27±12．38，彩色增强面积为（82．38±9．92）％，均高于其他组（P〈0．05）。彩色能量谐波造影较二维谐波造影增强的时间长且强度大。结论造影增强彩色显像可有效地观察肾脏血流灌注特征。     

超声造影检测肝血流动力学改变在诊断肝转移癌中的价值

目的探讨超声造影检测肝血流动力学改变在诊断肝转移癌中的价值。方法经肘静脉团注声诺维造影剂（0．6ml）后利用时间一强度分析软件对41例肝转移癌患者（肝转移癌组）和18例健康志愿者（正常对照组）的肝动脉到达时间、肝动脉峰值时间、肝动脉峰值强度、肝静脉到达时间、肝静脉峰值时间和肝静脉峰值强度进行测定，并计算出肝动静脉渡越时间。结果肝转移癌组的肝动脉到达时间、肝动脉峰值时间、肝静脉到达时间和肝静脉峰值时间均较正常对照组提前（P〈0．01），肝动脉峰值强度和肝静脉峰值强度高于正常对照组（P〈0．01），肝动静脉渡越时间较正常对照组缩短（P〈0．001）。结论超声造影检测肝血流动力学改变有助于肝转移癌的诊断。     

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.     

手转胎头术失败的原因与分娩结局临床分析

目的 探讨手转胎头术失败的原因与分娩结局.方法 选择2008年1月至2010年12月于我院住院分娩的持续性枕横位、枕后位产妇198例,根据行手转胎头术后结果分为成功组126例、失败组72例.比较两组分娩结局,对比分析失败原因.结果 失败组胎儿体质量≥3500 g的发生率[76.4％(55/72)]明显高于成功组[31.7％(40/126)],差异有统计学意义(x2=30.177,P=0.001)、失败组宫缩乏力发生率[58.3％(42/72)]高于成功组[38.1％ (48/126)],差异有统计学意义(x2=7.569,P=0.006)、失败组骨盆临界或轻度狭窄发生率[38.9％ (28/72)]高于成功组[23.8％(30/126)],差异有统计学意义(x2 =5.030,P=0.002)、失败组手转胎头时机不当(宫口开大＜6 cm、胎头位于坐骨棘上及宫口开大8～10 cm、胎头位于坐骨棘下≥2 cm)发生率[61.1％(44/72)]高于成功组[38.9％(49/126)],差异有统计学意义(x2=9.084,P=0.003).失败组母儿并发症(产后出血、产褥病率、胎儿窘迫、新生儿窒息)发生率高于成功组(x2 =9.586,P=0.002、x2=9.334,P=0.002、x2=5.910,P=0.015、x2=5.240,P=0.022)、失败组剖宫产发生率[72.2％(52/72)]明显高于成功组[34.1 ％(43/126),x2=26.641,P=0.001)].结论 手转胎头术能使难产变顺产,降低剖宫产率,减少母儿并发症,但须积极预防、处理导致手转胎头术失败的原因,对矫正失败后继续矫正及试产应慎重.