CDFI在儿童过敏性紫癜致急性双下肢静脉瓣膜功能不全中的应用

目的:探讨CDFI在儿童过敏性紫癜至下肢静脉瓣膜功能不全中的应用,以提高临床认识。方法:对经临床诊断过敏性紫癜引发下肢静脉瓣膜功能不全5例患儿图像资料给以回顾、归纳总结。结果:5例患儿下肢深静脉表现血液流速稍减慢,CDFI呈节阶段性红蓝相间血流,频谱多普勒呈节段性基线上下血流频谱。结论:CDFI为儿童急性过敏性紫癜致急性双下肢静脉瓣膜功能不全,提供了早期、无创和具有高敏感性、特异性的检查方法,对临床的诊治有重要价值。     

Doppler evaluation of maternal and fetal vessels during normal gestation in rabbits

The aim of this work was to evaluate the hemodynamic changes in the utero-placental arterial vessels in rabbits (Orictolagus cuniculus) throughout pregnancy as well as those in the umbilical cord, aorta, and caudal vena cava of fetuses to establish their normal reference ranges for systolic peak velocity (SPV), end diastolic velocity (EDV), pulsatility index (PI), and resistance index (RI). The blood flow waveforms were monitored every 4 d in 10 rabbits from Day 10 of pregnancy onward by means of color and pulsed wave Doppler ultrasonography using a 5.5-7.5 MHz microconvex transabdominal probe. The utero-placental blood flow was characterized by steep increases and decrease in the SPV with a slow diastolic wave and relatively high EDV, whereas that of the umbilical artery was discontinuous until Day 22 of pregnancy, when a diastolic waveform was also detectable. From Day 10 to 22 of pregnancy, the fetal aorta blood flow was discontinuous, but thereafter a diastolic peak was measurable. The blood flow of the fetal caudal vena cava was characterized by a systolic peak followed by a small diastolic peak. Throughout the gestation, the SPV and the EDV of maternal and fetal vessels increased (α < 0.05), whereas the PI and the RI decreased (α < 0.05), except for the utero-placental vessels. This work confirms that the rabbit could also be a valid experimental animal model to study, by Doppler ultrasonography, functional hemodynamic changes of the fetuses and placenta vessels in both normal and pathophysiologic conditions.     

大蹄蝠多普勒正负补偿效应的声波特征与比较

利用单摆装置模拟大蹄蝠的飞行状态并实时记录其回声定位信号,以研究其多普勒频移补偿行为。与其静息状态下的超声波特征比较,发现大蹄蝠在接近目标的过程中有多普勒正补偿效应:叫声频率随相对速度改变而成正相关变化;当相对速度最大时,其叫声频率相对静息状态频率降低最多,而相对速度为零时,叫声频率回复到静息时频率。而当大蹄蝠远离目标时,有多普勒负补偿效应:叫声频率随相对速度改变成正相关变化,叫声频率在相对速度最大时,升高最多,但相同速度下升高之值较正补偿值低得多。另外,负补偿效应出现的频率较正补偿值低,这可能是由蝙蝠生理结构的限制以及自然状态下罕见的多普勒负补偿条件所决定。     

Near-bottom performance of the Acoustic Doppler Velocimeter (ADV) – a comparative study

In a laboratory flume, a comparative study on the near-bottom performance of the Acoustic Doppler Velocimeter (ADV) was conducted. Two different ADV systems were tested for different configurations and two flow velocities (9 cm s⁻¹, 18 cm s⁻¹). The results were compared with synchronous measurements with a Laser Doppler Anemometer (LDA). Near-bottom velocity measurements with the ADV have to be interpreted carefully as the ADV technique underestimates flow velocities in a zone close to the sediment. The height of this zone above the sediment varies with different ADV systems and configurations. The values for nominal sampling volume height (SVH) given by the software often underestimate the true, effective sampling volume heights. Smaller nominal SVH improve the ADV near-bottom performance, but the vertical extent of the zone in which the ADV underestimates flow by more than 20% may be larger than true SVH/2 by a factor of 2 (=true SVH). When the measurement volume approaches the bottom, ADV data quality parameters (signal-to-noise-ratio (SNR) and signal amplitude) exceeding the average ‘open water’ level, are clear indicators that the ADV has begun to underestimate the flow velocity. Unfortunately, this is not a safe indicator for the range of reliable measurements as the ADV may begin to underestimate velocities even with unchanged ‘open water’ data quality parameters. Thus, one can only recommend avoiding measurements below a distance from the bottom that was defined empirically comparing the ADV and the LDA velocity profiles. This distance is 2.5 times nominal sampling volume height for the tested ADV systems and experimental settings.     

The functional anatomy of cerebral reorganisation after focal brain injury

Stroke is a major cause of disability in all age groups. Although the value of specific rehabilitative therapies is now acknowledged, the mechanisms of impairment and recovery are not well understood. There is growing interest in the role that central nervous system reorganisation might play in the recovery process, and in particular whether this reorganisation can be manipulated to provide clinical benefits for patients. The careful use of non-invasive techniques such as functional magnetic resonance imaging and transcranial magnetic stimulation allows the study of the working human brain, and studies in humans suggest that functionally relevant adaptive changes occur in cerebral networks following stroke. An understanding of how these changes influence the recovery process will facilitate the development of novel therapeutic techniques that are based on neurobiological principles and will allow the delivery of specific therapies to appropriately targeted patients suffering from stroke.     

A new method to model change in cutaneous blood flow due to mechanical skin irritation part I: comparison between experimental and numerical data

Mechanical skin irritation creates vasodilation. Vasodilation of vascular networks induces increase in blood volume and blood velocity. Both can be measured by Laser Doppler Velocimetry. We propose in this article a method permitting comparison between experimental and numerical results. Experimental data was obtained by Laser Doppler Velocimetry. Numerical results were obtained by a continuous model of the vascular network. The model consists of three layers. First and last layer are described by anisotropic and heterogeneous porous media. They represent the irrigation and the drainage of the vascular system. The intermediate layer is described by a lumped parameter model that does not permit horizontal fluxes. All vessels are compliant. The permeabilities depend on the volumes of the specific layer. Skin irritation is modeled by a change in compliance of small arterial blood vessels. The comparison between experimental and numerical data is based on the model proposed by Bonner and Nossal [1981. Model for laser Doppler measurements of blood flow. Appl. Opt. 20, 2097-2107]. The model describes the Doppler frequency spectrum S(omega) as a function of the optical phenomena creating the frequency shift. The comparison is based on the model of the first moment M1 approximately integralomegaS(omega)domega. The variables of the first moment can be determined by results of the numerical model. We have shown, that it exists a linear relation between the change in compliance and the following increase in first moment. Using this linear relation experimental and numerical data can be compared.     

稻纵卷叶螟(Cnaphalocrocis medinalis)迁飞的多普勒昆虫雷达观测及动态

在2007年7～9月江淮稻区稻纵卷叶螟大发生期间,利用多普勒昆虫监测雷达在南京市浦口区对稻纵卷叶螟成虫的迁飞活动进行了监测,结合大气风温场的数值模拟,研究了稻纵卷叶螟成虫的空中飞行参数和种群迁飞动态。结果表明：稻纵卷叶螟多选择在黄昏18：30以后大规模起飞,空中虫群密度在20：00～22：00时最大,迁飞过程可持续到次日5：00;稻纵卷叶螟主要选择在500m以下高度飞行。空中虫群具有聚集成层的现象,虫层多在100～500m高度之间形成,有时形成两个虫层,成层现象与低空急流关系密切,与温度没有直接关系。迁飞过程分析表明,浦口区的六（4）代稻纵卷叶螟在台风、副热带高压和江淮气旋的影响下,先后出现了多次迁入迁出过程。低压系统外围的下沉气流很可能是稻纵卷叶螟两次集中迁入的主要原因。     

彩色高频超声多普勒在男性乳腺增生症中的诊断价值

目的:探讨彩色高频超声多普勒在男性乳腺增生症中的应用价值.方法:收集我院2010年8月至2012年9月门诊及住院疑似男性乳腺增生症患者63例,应用彩色高频超声对63例(77只)男性乳腺增生症患者检查,分析其声像图特点并采用自身前后对照的方法与临床走访或病理诊断相比较.结果:超声诊断男性乳腺增生60例(74只),疑为男性乳腺癌2例,疑为增生伴炎性改变1例.临床或病理证实男性乳腺增生63例(77只).彩色高频超声多普勒在诊断男性乳腺增生上与临床金标准相比,符合率为96.1％.结论:彩色高频超声诊断男性乳腺增生症是一种准确、无创、简便的方法,有较高的应用价值.     

小脑后下动脉瘤经微血管多普勒超声辅助下的显微外科治疗

目的：探讨小脑后下动脉瘤（PICA）的微血管多普勒超声（MVD）辅助下显微外科治疗。方法：回顾性分析31例患者的显微外科手术的临床症状,影像特点,外科治疗方法及相关预后。结果：头颅CT表现主要为幕下为主的蛛网膜下腔出血或脑室出血或二者兼有（除1例未破裂）。其中经全脑数控减影血管造影术（DSA）和/或CT血管造影（CTA）检查确诊。其中手术路径为枕下旁正中16例,枕下正中入路14例,枕下乙状窦后入路1例。在MVD的辅助下行脉瘤夹闭术27例,动脉瘤包裹术1例,动脉瘤夹闭并动静脉畸形切除术2例,动脉瘤夹闭术并小脑血肿清除术1例。术后出现并发症10例,其中3例意识障碍致死亡或自动出院,其余患者术后无神经功能损伤或并发症,恢复良好。结论：小脑后下动脉瘤的治疗选择合适的手术入路行显微外科手术,辅助MVD下,能够降低手术风险,提高完全夹闭动脉瘤的成功率,降低手术并发症的发生。