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We have previously reported that the maximal inferior vena cava(IVC) diameter during quiet expiration(IVCe) measured by ultrasonography correlates well with the amount of body fluid, especially the circulating blood volume[1] and proposed using the criteria of IVC diameter to determine dry weight(DW) in anuric hemodialyzed (HD) patients: standard IVCe of pre-and post-HD are (14.9±0.4) and (8.2±0.3) mm, respectively[2]. However, the same post-HD IVC criterion should not be applied to nonoliguric HD patients because it could result in rapid deterioration of residual renal function due to forced dehydration. Although the biochemical DW marker plasma atrial natriuretic peptide (ANP) is useful to evaluate hypervolemia but not hypovolemia,both hyper-and hypovolemia can be detected by IVC measurement.
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磁共振灌注成像在颅内占位性病变中的应用(综述)
常规磁共振(MR)检查对于颅内肿瘤的发现和定性有很大价值,但在估计肿瘤的恶性程度、区分肿瘤复发与放、化疗后坏死等方面仍存在很大限制.近年来,MR灌注成像(perfusion MR,PMR)通过测量几个血流动力学参数来观察脑的微循环灌注,用于评价急性脑梗死、脑肿瘤、脱髓鞘病变以及治疗效果等[1],较常规CT、MR有独特的优点.这些参数包括脑血容量(cerebral blood volume,CBV)、脑血流量(cerebral blood flow,CBF)及平均通过时间(mean transit time,MTT)等.其中,用于颅内占位性病变的研究已有多量报道,且主要集中于脑胶质瘤的术前分级诊断.在评价颅内占位性病变中,以CBV有价值[2].
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穿支低灌注发病机制在内囊预警综合征病因中的参与二例
例1:患者男,66岁,既往"2型糖尿病"病史,反复发作性左侧肢体力弱5h,再发无缓解1h于2010年6月14日9:00入院,入院前反复发作4次,1h前再发无缓解,体征:左侧肢体肌力4级,左侧巴氏征(+),急诊CT血流灌注成像(computerized tomography perfusion,CTP)检查提示右侧基底节区低灌注:脑血流量(cerebral blood flow,CBF)增加、脑血容量(cerebral blood volume,CBV)略增加、平均通过时间(mean transit time,MTr)延长,颈动脉+头颅CTA未见明显异常,24h后左侧肢体力弱仍无缓解,头颅DWI检查提示右侧基底节脑梗死,见图1.
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应用能谱CT研究肝硬化门静脉高压患者肝血流动力学变化
肝血流CT灌注扫描可获取肝动脉指数(hepatic artery index,HAI)、肝血流量(hepatic blood flow,HBF)、肝血容量(hepatic blood volume,HBV)、平均通过时间(mean transit time,MTT)、表面通透性(permeability of capillary vessel surface,PS)等肝灌注参数[1-3].
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CT脑灌注成像在神经内外科的临床应用进展
近年来,功能成像技术迅速发展,拓宽了放射学的诊断范围,尤其在神经放射学领域,已经超出了以往形态影像学的范畴.CT脑灌注成像(Computed Tomography Perfusion;CTP)作为一种功能成像技术,借助专用软件定量测定脑血流量(Cerebral Blood Flow;CBF)、脑血容量(Cerebral Blood Volume;CBV)和平均通过时间(Mean Transit Time;MTT)并生成脑灌注图像,进而评估脑灌注情况.以往测量研究脑灌注的方法有磁共振成像(Magnetic Resonance Imaging;MRI)、正电子发射体层摄影(Positron Emission Tomography;PET)、单光子发射计算体层摄影(Single-photon Emission Tomography;SPECT)、氙CT(Xe-CT)等[1],但由于这些检查耗时长、价格昂贵、需要吸入有麻醉作用的氙气等原因,限制了其在临床的应用.
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高原小儿外科感染性休克探讨
本文对105例高原小儿外科感染性休克进行了总结.临床观察和实验室资料表明,高原地区健康小儿的血液流态具有粘、浓、聚三大特点,微血管在缺氧环境下处于痉挛代偿状态.感染性休克时血管痉挛明显加重,持续时间长,代偿机能差,休克早期就会出现微循环障碍,因而高原小儿感染性休克具有发病急、进展快,病情重、病死率高等临床特点.早期诊断、早期治疗对于提高抢救成功率,降低病死率有重要意义.
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三维CT脑灌注血容量成像研究
动态CT脑灌注成像(computed tomography perfusion,CTP)能够反映脑内血流灌注情况,快速、可靠的评价血流动力学改变,在诊断急性脑缺血方面一直是研究热点[1,2].由于CTP是二维技术,且检查范围受到限制,即使采用64排螺旋CT也仅能进行40 mm扫描,通常无法显示全脑灌注情况[3,4].三维CT脑灌注血容量(perfused blood volume,PBV)成像主要是利用增强CT血管造影(CT angiography,CTA)图像获得,能够多方位显示脑灌注异常范围[5-7].本文对其概念、成像和后处理方法、初步临床应用作一介绍.
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指端光电容积脉搏波测量实验
由于指端光电脉搏图形与颈动脉及桡动脉搏动图形极为相似,可推断它们的生理学意义是相似的.临床工作中常用于血氧饱和度、心率等测量,是一种很好无创伤检测方法.为了使学生更好地了解指端光电容积脉搏波测量原理与心电图机的使用,我室开发设计了指端光电容积脉搏波测量这一实验.
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血定安用于术中低血容量的临床观察
血定安是新一代明胶改良配制的血浆代用品.通过对30例成人腹部手术患者不输血而输注血安定以观察其血液动力学和血系生化的变化.
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动脉自旋标记技术在颅内肿瘤中的临床应用进展
灌注是指血流通过毛细血管网,将携带的氧和营养物质输送给组织细胞的一种基本生物功能。磁共振灌注成像凭借其对微血管灌注的敏感性,已经广泛应用于临床各方面,包括对肿瘤的鉴别,脑梗死区域的界定,以及其他疾病的诊断。磁共振灌注成像可分为2大类,即对比剂首过磁共振灌注成像法和动脉自旋标记(arterial spin labeling,ASL)法。前者需要静脉注射顺磁性对比剂,如 Gd-DTPA 或 SPIO,然后进行快速 MR 扫描,在其分类中,动态磁敏感对比成像(dynamic susceptibility contrast,DSC)不仅拥有较高的空间分辨率,还能同时测量大脑血流量(cerebral blood flow, CBF)和脑血容积(cerebral blood volume,CBV),因而在临床上广泛应用。然而,ASL 却无须注射外源对比剂就能够测量脑血流量,是近年发展起来的一种 MRI灌注新技术。由于 ASL 技术具有安全无创、成本低廉、简单方便、可重复性好等优点,并且可对肿瘤的血管生成进行准确评估,已逐渐成为颅内肿瘤病变诊断、治疗及预后评估研究的新热点。本文就 ASL 技术的工作原理、分类及其在颅内肿瘤的应用做一综述。
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Objective: To develop an on-line system for the measurement of blood viscosity and hematocrit. The dynamic changes of the macrovascular blood volumes,microvascular blood volumes and the total blood volume were observed by means of calculating from the testing result.Methods: Applying traditional viscosity measurement principle and specific wavelength optic density measurement method, an on-line system for the measurement of blood viscosity and hematocrit was developed, and the A/D multifunctionai board and the testing circuit were designed by ourselves. The system was validated by experiments both in vitro and in vivo. Therapeutic effects of hypertonic saline dextran solution (HSD) and Lactatic Ringer's solution at the early stage after burn-blast combined injury were compared by this method.Results: The results showed that the system has attained the goal of the design. The changes of the blood viscosity and hematocrit could be detected effectively and continuously. The changes of macrovascular, microvascular and total blood volume could be calculated approximately.Conclusions: The system and the method can continuously on-line test the blood viscosity and hematocrit, and reveal the change and distribution of blood volumes more accurately and dearly in the therapy process by estimating changes of the macrovascular, microvascular and total blood volumes, respectively. It has confirmed that HSD treatment could increase blood pressure and attenuate tissue edema by significantly increasing total blood volume,improving macrocirculatory and microcirculatory blood volumes. This study suggested that it could be desirable to develop an experiment technique based on the method mentioned above.