激光多普勒血流计在全息穴位上的应用

激光多普勒血流计在全息穴位上的应用文／于泉丽激光多普勒血流计（ＬＤＦ）可以测量皮肤和内脏微区血流量（Ｍｉｃｒｏｂｌｏｏｄｆｌｏｗ，ＭＢＦ）［１］，已应用于皮肤、内脏以及穴位上的测量，但在全息穴位上的应用还未曾见有报道。本文根据全息生物学理论，用ＬＤＦ...     

一般化光电流光谱因素和激光多普勒测流速度分布矫正

一般化光电流光谱因素和激光多普勒测流速度分布矫正〔英〕／ＺｈｏｎｇＪ…／／ＩＥＥＥＴｒａｎｓＢＭＥ．１９９３，４０（６）．５９５激光多普勒测流技术（ＬａｓｅｒＤｏｐｐｌｅｒＦｌｏｗｍｅｔｒｙ－ＬＤＦ）是一种测量组织中血液流动的非侵入测量方法。通过计算...     

环境温度影响大鼠脏器微循环血流量的实验研究

目的 研究环境温度对正常大鼠和微循环障碍大鼠外周和内脏微循环血流量的影响。方法 用激光多普勒微循环血液仪（ＬＤＰ）测定下沉大鼠和微循环障碍大鼠的外周和内脏的微循环血流量相对值。     

微循环障碍大鼠脏器微循环灌流量的动态变化

微循环障碍可发生于创伤、炎症等许多疾病过程中,它的主要表现为组织微循环灌流量的减少。过去对微循环障碍动物模型的研究主要集中在血流紊乱、形态变化以及血液流变学测定等方面。激光多普勒微循环血流仪(LDF)可以无创地测量脏器和皮肤表面的微循环血液灌流量相对变化,为研究微循环血液灌流量动态变化提供了一个新的手段。本实验用LDF对大鼠微循环障碍模型的多脏器微循环血液灌流量动态变化进行了观察,并同时测量了血压和心率,为这个模型的实验应用提供了参考依据。     

山莨菪碱对带蒂皮瓣血流量的影响及断蒂指征的探讨

我们应用激光多普勒血流仪对家兔带蒂皮瓣形成术前、后及断蒂后４８ｈ微循环血流进行测量。结果表明：①于皮瓣形成术后测量皮瓣中点血流量,实验组均高于对照组,提示山莨菪碱可以增加皮瓣的血流量。②皮瓣蒂部阻断后,中点ＬＤＦ值达到阻断前的５０％水平时断蒂,皮瓣不一定最终存活,应结合其他指征综合分析。     

实验高压电烧伤肾皮质血液灌流量的动态变化及意义

目的探讨高压电烧伤早期肾皮质血液灌流 (RCHP)的变化及其机制。方法采取重复测量设计 ,分实验组和对照组 ,先制作高压电烧伤动物模型 ,再应用LISCA激光多普勒组织灌流图像仪(LDPI)连续观测家兔电烧伤前后8h内肾皮质血液灌流量及尿量的改变。结果正常RCHP值(2.60±0.73)V ,电烧伤即刻 ,灌流值为(1.41±0.45)V(P<0.05) ,电烧伤后1h ,RCHP值(2.08±0.30)V(P<0.05) ,电烧伤1h后 ,灌流值减小。电烧伤后2h,尿量明显减少 ,到伤后8h ,尿量平均每小时0.2ml。结论高压电烧伤导致肾皮质血液灌流量及尿量减少。     

低氧及常氧灌流对离体大鼠心脏应激蛋白的诱导

目的和方法：观察低氧灌流和常氧灌流诱导离体大鼠心脏的应激蛋白合成。结果：低氧和常氧灌流均可诱导３个分子量为７０ｋＤａ的一组应激蛋白（ｓｐ６８，７０和７２）合成显著增加，５个分子量为６０ｋＤａ的一组应激蛋白（ｓｐ５４－６５）合成也有所增加。比较不同灌流方式和时程对应激蛋白合成的影响，发现７０ｋＤａ的一组应激蛋白合成量在常氧灌流的离体心脏中高于低氧灌流；并且该组应激蛋白合成量在经两种灌流方式处理１ｈ的以脏高于灌流处理２ｈ的心脏。结论：应激蛋白合成量并不与应激原的迭加或与细胞受环境损害的严重性成正比。对灌流的离体心脏而言，缺血可能是诱导应激蛋白合成的主要因素，低氧及常氧则起调节合成量的作用     

老年糖尿病患者指腹及足背微区血流的观察

目的寻找糖尿病并发微血管病变的早期依据,为临床活血化瘀疗法提供有效观察指标。方法糖尿病组９例。男性、均有不同程度神经和血管并发症。病程１～３０年以上、非糖尿病组９例,冠心病、高血压,其他疾病各３例,男性。用ＬＤＦ－Ⅱ型激光多普勒血流仪,测量范围为１．５ｍｍ半径的半球体微区、血流量单位为多普勒信号的电压值“Ｖ”。测定部应为左、右中指指腹及左、右足背。定时记录,每一部位观察１５ｍｉｎ、结果糖尿病组上肢皮肤血流量、血液灌注波型和非糖尿病组相比无差异;糖尿病组下肢皮肤血流只有 ７２．２％的微区呈现高、低灌流相,明显低于非糖尿病组（１００％）,且其高、低灌流相持续时间及两灌流相上升、下降时间均明显延长。结论糖尿病微区血流改变是由于下肢皮肤血管病变发生后,代偿性增加血液供应而致。     

一氧化氮在大鼠创伤局部微循环灌流减少中的作用

目的和方法：用激光多普勒微循环血流仪测定大鼠断肢局部微循环血液灌流量，用比色法测定血浆亚硝酸盐（ＮＯ２－）水平间接反映血浆一氧化氮（ＮＯ）含量。结果：（１）断肢局部微循环血液灌流量在断肢Ｏ、１、２和３ｈ均明显下降，局部股静脉血浆ＮＯ２－含量在断肢２、３ｈ显著降低，断肢２、３ｈ局部股静脉血浆ＮＯ２－水平与局部微循环血液灌流量呈显著正相关。（２）ＮＯ合成底物左旋精氨酸（Ｌ－Ａｒｇ）能改善断肢２、３ｈ的局部微循环血液灌流量，一氧化氮合成抑制剂左旋单甲基精氨酸（Ｌ－ＮＭＡ），可抑制此作用。（３）断肢３ｈ局部股静脉血浆ＮＯ２－水平Ｌ－Ａｒｇ组明显高于生理盐水（ＮＳ）组（Ｐ＜００５），Ｌ－Ａｒｇ合用Ｌ－ＮＭＡ组则明显低于ＮＳ组（Ｐ＜００５）。结论：断肢创伤通过内源性Ｌ－Ａｒｇ－ＮＯ通路而降低ＮＯ生成，参与断肢局部２、３ｈ的血管痉挛和微循环血液灌流量下降     

高压氧对鼠牙龈微血管及微循环的作用

探讨高压氧（ＨＢＯ）对牙龈微循环的作用及其机理。方法：从组织学和用激光多普勒血流仪（ＬＤＦ）分析ＨＢＯ对鼠牙龈血管数目、形态、超微结构的影响，及对牙龈血流量（ＧＢＦ）、血流速度（ＢＣＶ）和血浓度（ＢＣ）的变化，进而分析ＨＢＯ对微循环的影响规律及与组织学变化的关系。结果：ＨＢＯ治疗组的血流量、血流速度和血浓度与相应的对照组比均有显著性差异，该组的血流量增加，血流速度加快，血浓度降低，ＨＢＯ对牙龈血流速度和血流量增加较明显；ＨＢＯ治疗后牙龈固有层微血管数目明显增多，血管壁增厚，血管内皮细胞胞浆中线粒体和内质网明显增多，细胞代谢加快。结论：ＨＯＮ可增加牙龈固有层开放的血管数目，促进血管内皮细胞的代谢水平，使牙龈血流量和血流速度增加，降低血浓度；ＨＢＯ可通过调节牙龈的血管数目和内皮细胞代谢而改变牙龈微循环。     

Comparison of laser speckle and laser Doppler perfusion imaging: Measurement in human skin and rabbit articular tissue

Laser Doppler perfusion imaging (LDI) is currently used in a variety of clinical applications, however, LDI instruments produce images of low resolution and have long scan times. A new optical perfusion imager using a laser speckle measurement technique and its use for in vivo blood flow measurements are described. Measurements of human skin and surgically exposed rabbit tissue made using this instrument were compared with a commercial laser Doppler perfusion imaging instrument. Results from blood flow measurements showed that the laser speckle imager measured an 11–67% decrease in blood flow under arterial occlusion. Under similar conditions, the laser Doppler imager measured blood flow decreases of 21–63%. In comparison with LDI, it was observed that the higher temporal resolution of the laser speckle imager was more sensitive to measuring the hyperaemic response immediately following occlusion. This in vivo study demonstrated some of the several advantages laser speckle imaging has over conventional LDI, making the new instrument more versatile in a clinical environment.     

In vivo comparison of scanning technique and wavelength in laser Doppler perfusion imaging: Measurement in knee ligaments of adult rabbits

At present, there are only two laser Doppler perfusion imaging systems (LDls) manufactured for medical applications: a ‘tepwise’ and a ‘continuous’ scanning LDI. The stepwise scanning LDI has previously been investigated and compared with coloured microsphere determined standardised flow. The continuous scanning LDI is investigated and compared with the stepwise scanning LDI for its ability to measure in vivo, hypoaemic, ligament tissue blood flow changes. The continuous scanning system was supplied with two lasers, red and near infrared (NIR), allowing for additional assessment of the effect of wavelength on imaging ligament perfusion. Perfusion images were obtained from surgically exposed rabbit medial collateral ligaments (MCL). Continuous and stepwise LDI scans were compared using correlation and linear regression analysis of image averages and standard deviations. Using the same method of analysis, LDI measurements using red and NIR lasers indicated a high degree of correlation, at least over the ranges of perfusion assessed, indicating that red and NIR lasers measure similar regions of flow in the rabbit MCL. These experiments confirm that both LDI techniques provide a valid in vivo measure of dynamic changes in connective tissue perfusion and could have significant impact on the understanding and treatment of joint injury and arthritis.     

Direct comparison of laser Doppler flowmetry and laser Doppler imaging for assessment of experimentally-induced inflammation in human skin

Objective and design

Laser Doppler imaging (LDI) and laser Doppler flowmetry (LDF) can measure localized skin perfusion. The purpose of the study was to directly compare LDF with LDI as a tool for measuring skin blood changes in an experimental model of chemically-induced skin inflammation.

Methods

Regions of interest 1.8 cm² in area on the forearm skin of eight healthy volunteers were randomized and exposed to 0.25, 0.5, 1, or 2 % topical sodium lauryl sulfate (SLS) or vehicle for 24 h. Mean blood flow was measured by LDI and LDF at 24, 48, and 72 h. Inflammation was clinically graded using a standardized, clinical score.

Results

Sodium lauryl sulfate induced significant, dose-dependent local inflammation. Both Doppler methods were significantly correlated with the clinical grading (LDF, r = 0.755; LDI, r = 0.836). LDF and LDI showed similar significance differences with regard to dose- and time-response patterns compared to the vehicle. The absolute and relative LDF and LDI values were significantly correlated.

Conclusions

Laser Doppler flowmetry and LDI showed similar dose- and time-response relations in irritant-induced inflammatory skin reactions. For the assessment of localized skin reactions, LDI possesses no apparent advantages over the less expensive LDF method for grading dermal inflammatory reactions.     

Evaluation of laser Doppler imaging to measure blood flow in knee ligaments of adult rabbits

Laser Doppler imaging (LDI) is investigated as a novel method for in vivo ligament tissue blood flow determination. LDI output signal is obtained from surgically exposed rabbit medial collateral ligaments (MCL). The LDI signal, is compared with simultaneously determined, coloured microsphere (CM)-derived standardised MCL blood flow. Correlation of LDI output with the CM flow data and a linear regression of 17 data points in nine rabbits (joint injured to provoke an acute vascular response in the tissues) indicate that LDI provides a reasonable estimate of MCL blood flow, at least over the ranges assessed. If properly calibrated, and given enough tissue-specific data points, LDI may have advantages over conventional, but more invasive, techniques. The potential clinical application of LDI technology to joint injury and arthritis research is discussed.     

Laser Doppler imaging evaluation of adipogenesis after adipose tissue-derived stem cell implantation

We need a better method of assessing adipose tissue formation non-invasively than the current one, which requires resecting tissue samples in vivo. The aim of this study was to establish a system to evaluate adipogenesis using laser Doppler imaging (LDI) to measure subcutaneous microcirculation. CGSs containing adipose stem cells with or without bFGF were implanted in the backs of 30 mice. Once per week after implantation, LDI was used to evaluate blood flow at the implantation site. The implantation sites were resected at 6 weeks, and the tissue was weighed. Six weeks after implantation, LDI showed that mice who received CGS with 1 μg/cm² bFGF had the greatest mean blood flow, and these mice had the heaviest resected specimens, which contained the most newly formed adipose tissue. The findings for LDI and the weight findings were compatible. This study indicates that LDI could be used to assess subcutaneous tissue regeneration in vivo in a real-time, non-invasive manner.     

A comparison between 133Xenon washout technique and Laser Doppler flowmetry in the measurement of local vasoconstrictor effects on the microcirculation in subcutaneous tissue and skin

Changes in skin blood flow measured by Laser Doppler flowmetry and changes in subcutaneous blood flow measured by 133Xenon washout technique were compared during activation of the local sympathetic mediated veno-arteriolar vasoconstrictor reflex by lowering the area of investigation below heart level. The measurements were performed in tissue with and without sympathetic innervation. In five subjects, who all had been cervically sympathectomized for manual hyperhidrosis, the Laser Doppler and 133Xenon blood flow measurements were performed simultaneously on the sympathetically denervated forearm, and on the calf with preserved sympathetic nerve supply. The Laser Doppler method registered a 23% reduction in skin blood flow during lowering of the extremities independently of the sympathetic nerve supply to the skin. The 133Xenon method recorded a 44% decrease in blood flow in innervated and unchanged blood flow in denervated subcutaneous tissue during lowering of the extremities. Our results indicate that the Laser Doppler method and 133Xenon method are not comparable, and that the Laser Doppler method is not useful in measuring local sympathetic mediated blood flow changes.     

Spectral signature and heterodyne efficiency for different wavelengths in laser Doppler flowmetry

Laser Doppler perfusion monitoring and imaging technologies generate time traces and two-dimensional flow maps of the microcirculation. With the goal of reaching different tissue depths, these technologies are equipped with lassers operating at different wavelengths λ. The fact that the average scattering angle, at a single scattering event, between a photon and a red blood cell increases with λ is compensated for by a 1/λ effect in the scattering vector, rendering the average frequency shift virtually independent of the choice of wavelength. Monte Carlo simulations showed that the corresponding spectral signature of the Doppler signals for λ=632.8nm and 780nm were close to identical. The theoretical predictions were verified by calculating the centre-of-gravity (COG) frequency of the laser Doppler power spectral density for the two wavelengths from forearm and finger skin, representing a low and high perfusion area, respectively (forearm COG=123 against 121Hz, finger COG=220 against 212 Hz). When the wavelength changes from 632.8nm to 780nm, the heterodyne efficiency of the detector and, thereby, the inherent system amplifcation increase. For tissues with identical microvascular flow conditions, the output signal therfore tends to increase in magnitude when shifting to longer wavelengths.     

Bioengineering assessment of acupuncture, part 2: monitoring of microcirculation

In the second part of the review article, monitoring of microcirculation during acupuncture is described. Laser Doppler flowmetry and laser Doppler imaging provide easy-to-use, noninvasive, real-time measurements of local tissue blood flow. Using these types of biomedical equipment, it is possible to quantify and objectify peripheral changes in microcirculation during different methods of acupuncture stimulation (manual needle acupuncture and laserneedle acupuncture).     

Model-based quantitative laser Doppler flowmetry in skin

Laser Doppler flowmetry (LDF) can be used for assessing the microcirculatory perfusion. However, conventional LDF (cLDF) gives only a relative perfusion estimate for an unknown measurement volume, with no information about the blood flow speed distribution. To overcome these limitations, a model-based analysis method for quantitative LDF (qLDF) is proposed. The method uses inverse Monte Carlo technique with an adaptive three-layer skin model. By analyzing the optimal model where measured and simulated LDF spectra detected at two different source-detector separations match, the absolute microcirculatory perfusion for a specified speed region in a predefined volume is determined. qLDF displayed errors<12% when evaluated using simulations of physiologically relevant variations in the layer structure, in the optical properties of static tissue, and in blood absorption. Inhomogeneous models containing small blood vessels, hair, and sweat glands displayed errors<5%. Evaluation models containing single larger blood vessels displayed significant errors but could be dismissed by residual analysis. In vivo measurements using local heat provocation displayed a higher perfusion increase with qLDF than cLDF, due to nonlinear effects in the latter. The qLDF showed that the perfusion increase occurred due to an increased amount of red blood cells with a speed>1 mm∕s.