In vivo label-free measurement of blood flow velocity symmetry based on dual line scanning third-harmonic generation microscopy excited at the 1700 nm window

Measurement of bloodflow velocity is key to understanding physiology and pathology in vivo.While most measurements are performed at the middle of the blood vessel,little research has been done on characterizing the instantaneous bloodflow velocity distribution.This is mainly due to the lack of measurement technology with high spatial and temporal resolution.Here,we tackle this problem with our recently developed dual-wavelength line-scan third-harmonic generation(THG)imaging technology.Simultaneous acquisition of dual-wavelength THG line-scanning signals enables measurement of bloodflow velocities at two radially symmetric positions in both venules and arterioles in mouse brain in vivo.Our results clearly show that the instantaneous bloodflow velocity is not symmetric under general conditions.

Influence of High-Velocity Blood Flow on Right-to-Left Shunt in Patients with Patent Foramen Ovale during the Valsalva Maneuver

In this study, we investigated the changes in the right-to-left shunt (RLS) of the patent foramen ovale (PFO) at different phases of the Valsalva maneuver and analyzed the possible mechanisms. The study population consisted of 57 patients with symptoms highly suggestive of a PFO. These patients had been diagnosed with apsychia, migraine with aura, cerebral infarction, transient ischemic attack (TIA), and cerebral ischemia with unknown cause. Routine echocardiography was performed in all patients to rule out a cardiac malformation. Contrast-transcranial Doppler (c-TCD) and contrast-enhanced transthoracic echocardiography (c-TTE) were used to visualize and quantify the RLS. The standard apical four chamber view was used to observe the changes of E peak, A peak, and velocity-time integral (VTI) ratio of tricuspid blood flow during the strain phase and release phase of the Valsalva maneuver. Paired t-test was used to compare E peak, A peak, and VTI ratio of tricuspid blood flow during the different phases. The right-to-left shunt across the PFO (PFO-RLS) was graded in the two phases and compared by Kruskal-Wallis test. Compared with the strain phase of the Valsalva maneuver, the parameters of E, A, and VTI in diastolic period in patients with PFO-RLS at the release phase were significantly increased [54.30 ± 13.65 cm/s vs 100.35 ± 21.11 cm/s, 42.21 ± 12.32 cm/s vs 57.30 ± 18.88 cm/s, 10.34 ± 3.27 cm/s vs 19.58 ± 4.56 cm/s, respectively], and the difference was statistically significant. The positive consequence of PFO-RLS, as diagnosed by c-TTE with the Valsalva maneuver at the release phase of the Valsalva maneuver, was significantly higher than that at the strain phase of the Valsalva maneuver. At the beginning of release phase of the Valsalva maneuver, decreased intrathoracic pressure led to increased venous backflow into the right atrium. Thus, high-velocity blood flow rapidly pushed the PFO open, which resulted in a significant increase in the PFO-RLS. Therefore, the increase of the PFO-RLS during the Valsalva maneuver is caused by the impact of high-velocity blood flow the PFO.

Trans-Thoracic Echocardiographic Aortic Blood Flow Peak Velocity Variation, Distance Minute, Aortic Velocity Time Integral and Postoperative Outcome in Pediatric Surgical Patients—An Observational Pilot Study Protocol

Background: A Randomized Controlled Trial (RCT) has been elaborated where goal directed fluid and hemodynamic therapy (GDFHT) will be realized with trans-thoracic echocardiographic aortic blood flow peak velocity variation (ΔVpeak) and distance minute (DM) to guide fluid therapy and hemodynamics in high risk pediatric surgical patients. This RCT will clarify the impact of GDFHT with ΔVpeak and DM on postoperative outcome in terms of morbidity, length of stay in the intensive care unit (LOSICU), length of mechanical ventilation (LMV) and length of hospital stay (LOS) in children. To determine values of ΔVpeak, DM and VTI predictive of these postoperative outcomes, an observational pilot study will be realized. This pilot study is described here. The primary objective of this study is to determine values of ΔVpeak, DM and ITV predictive of postoperative outcome in children in terms of morbidity. The secondary objectives are to determine values of ΔVpeak, DM and ITV predictive of LOSICU, LMV, LOS, intraoperative, postoperative fluid administration and vasoactive-inotropic therapy. Methods: 500 - 1000 children aged less than 18 years will be included prospectively. Statistic analysis will be realized with XLSTAT 2019.4.2 software or plus. Results and Conclusions: This trial protocol will determine values of ΔVpeak, DM and ITV with echocardiography predictive of postoperative outcome in children.

Optimal velocity encoding during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography

This study investigated the effect of velocity encoding on measurement of brain blood flow and blood volume of inflow and outflow using phase-contrast magnetic resonance angiography. A single two-dimensional phase-contrast magnetic resonance angiography slice was applied perpendicular to the internal carotid artery and the vertebral artery at C2 level. For each subject, the velocity encoding was set from 30 to 90 cm/s with an interval of 10 cm/s for a total of seven settings. Various velocity encodings greatly affected blood flow volume, maximal blood flow velocity and mean blood flow velocity in the internal carotid artery, but did not significantly affect vertebral arteries and jugular veins. When velocity encoding was 60-80 cm/s, the inflow blood volume was 655 _＋ 118 mL/min, and the outflow volume was 506 _＋ 186 mL/min. The ratio of outflow/inflow was steady at 0.78-0.83, and there was no aliasing in any of the images. These findings suggest that velocity encodings of 60 80 cm/s should be selected during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography.

The Effects of Chinese Medicines on Micro-circulation of Nail Folds and Blood Flow Velocity of Limbs in the Patients with Arteriosclerotic Obliteration

The effects of Chinese medicines on micro-circulation and blood flow velocity in arteries of the lower limbs were observed in 33 patients with arteriosclerotic obliteration(ASO).The results showed that the integral values of micro-circulation after treatment were obviously higher than those before treatment (P<0.05 or P<0.01).Blood flow velocity in arteries of the lower limbs determined with the color Doppler ultrasound detecting method after treatment were also obviously higher than those before treatment (P<0.05 or P<0.01).In tbis series of 33 ASO patients,the markedly effective rate was 36.36%,and the total effective rate was 63.64%.The observation indicates that the recipe prescribed according to the principle of supplementing qi and activating blood circulation can effectively improve micro-circulation in ASO patients,and accelerate blood flow in arteries of the lower limbs.

A FREQUENCY DOMAIN QUANTITATIVE MEASUREMENT METHOD FOR BLOOD FLOW VELOCITY WITH BIDIRECTIONAL DOPPLERULTRASOUND AVOIDING DOWN-BAND CHANNEL

The up-band signal of the second ultrasonic beam contained reversecomPOnent or blooll now. Using double ultrasonic beam,bidirectional Doppler ultrasound can avoid the use or two kinds or band filters and be simplified into a singlekind or band filter. In order to make the output more accurate,the inrluence of angle effect can be overcome by the table-out method and another special methodcalled cose recorrection.The experiment result is that when the deviation angle varies from-- 18' to +20' the relative error or output is less than 5%.

Wrist blood flow signal-based computerized pulse diagnosis using spatial and spectrum features

ABSTRACT Current computerized pulse diagnosis is mainly based on pressure and photoelectric signal. Considering the richness and complication of pulse diagnosis information, it is valuable to explore the feasibility of novel types of signal and to develop appropriate feature representation for diagnosis. In this paper, we present a study on computerized pulse diagnosis based on blood flow velocity signal. First, the blood flow velocity signal is collected using Doppler ultrasound device and preprocessed. Then, by locating the fiducial points, we extract the spatial features of blood flow velocity signal, and further present a Hilbert-Huang transform-based method for spectrum feature extraction. Finally, support vector machine is applied for computerized pulse diagnosis. Experiment results show that the proposed method is effective and promising in distinguishing healthy people from patients with cho- lecystitis or nephritis.

Blood Flow Simulation in the Femoral Artery

This paper presents the development of the blood flow simulation in two dimensions over the real geometry of the femoral artery. The Navier-Stokes equations are solved using the finite element method, to obtain the distributions of the blood pressure and flow velocity in multiple instants of time and different places of the femoral artery and thus determine the current condition of the blood vessels. The velocity field shows a laminar behavior,where, the velocity is higher in the center of the artery and decreases as the blood flow approaches artery walls. In spite of all artery and blood flow properties not being considered, the values of pressure and velocity obtained are within the normal ranges. Finally the model is used to verify if there exist irregularities in the blood flow in both healthy subjects and sick patients.

Cerebral blood flow volume measurements of the carotid artery and ipsilateral branches using two-dimensional phase-contrast magnetic resonance angiography

The optimal velocity encoding of phase-contrast magnetic resonance angiography （PC MRA） in measuring cerebral blood flow volume （BFV） ranges from 60 to 80 cm/s. To verify the accuracy of two-dimensional （2D） PC MRA, the present study localized the region of interest at blood vessels of the neck using PC MRA based on three-dimensional time-of-flight sequences, and the velocity encoding was set to 80 cm/s. Results of the measurements showed that the error rate was 7.0±6.0% in the estimation of BFV in the internal carotid artery, the external carotid artery and the ipsilateral common carotid artery. There was no significant difference, and a significant correlation in BFV between internal carotid artery ＋ external carotid artery and ipsilateral common carotid artery. In addition, the BFV of the common carotid artery was correlated with that of the ipsilateral internal carotid artery. The main error was attributed to the external carotid artery and its branches. Therefore, after selecting the appropriate scanning parameters and protocols, 2D PC MRA is more accurate in the determination of BFV in the carotid arteries.

RETINAL SPECTRAL IMAGING AND BLOOD FLOW MEASUREMENT

Measurement of both oxygen saturation and blood flow in the retinal vessels has proved to give important information about the eye health and the onset of eye pathologies such as diabetic retinopathy.In this study,we present the implementation,on a commercially available fundus camera,of a retinal imager and a retina blood flow velocimeter.The retinal imager uses division of aperture to acquire nine wavelength-dependent sub-images of the retina.Careful consideration is taken to improve image transfer by measuring the optical properties of the fundus camera and modeling the optical train in Zemax.This part of the setup is calibrated with optical phantoms of known optical properties that are also used to build a lookup table(LUT)linking phantom optical properties to measured reflectance.The retina blood flow velocimeter relies on tracking clusters of erythrocytes and uses a fast acquisition camera attached to a zoom lens,with a green illumination LED-engine.Calibration is provided using a calibrated quartz capillary tube and human blood at a known flow rate.Optical properties of liquid phantoms are retrieved from measured reflectance using the LUT,and blood flow measurements in the retina are presented.

A Mathematical Model for Pulsating Flow of Ionic Fluid under an Axial Electric Field： EMF Effect on Blood Flow

The present work introduces a mathematical model for ionic fluid that flows under the effect of both pulsating pressure and axial electromagnetic field. The fluid is treated as a Newtonian fluid applying Navier-Stokes equation. The fluid is considered as a neutral mixture of positive and negative ions. The effect of axial electric field is investigated to determine velocity profiles. Hydroelectric equation of the flow is deduced under dc and ac external electric field. Hence the effect of applied frequency （0-1 GHz） and amplitude （10-350 V/m） is illustrated. The ultimate goal is to approach the problem of EMF field interaction with blood flow. The applied pressure waveform is represented as such to simulate the systolic-diastolic behavior. Simulation was carried out using Maple software using blood plasma parameters; hence velocity profiles under various conditions are reported.

Close Correlations Between Carotid Arterial Mean Blood Flow Velocity,Body Mass Index,and Temperature in Normal Individuals

Objective:Assessing carotid and radial pulses is an essential sphygmology method in traditional Chinese medicine(TCM).It is believed in TCM and by doctors that pulse force is markedly linked with the physiological state of a human,including body mass index(BMI)and temperature.However,comprehensive analysis elucidating these potential correlations remains undetermined.Therefore,this investigation aimed to assess the association of pulse strength with human metabolism.Materials and Methods:The mean blood flow velocity(MBFV)of the carotid artery and pulse force of 122 healthy adults included in this investigation were assessed using ultrasound and manual palpation.Their thermal texture map was also acquired.Results:No substantial variation was observed in the carotid arterial MBFV among normal individuals(P>0.05)regardless of body side and gender.However,young individuals had higher blood velocity than middle-aged individuals(P<0.05).Furthermore,it was identified that MBFV was negatively associated with BMI and torso temperature;however,it was positively linked with hand temperature.Conclusions:This investigation revealed that carotid arterial MBFV could indicate the physical state of humans,including BMI and temperature,and therefore,is valuable for elucidating the effect of TCM on yin–yang.The data validated some TCM beliefs and supported the implementation of sphygmology in TCM.

EFFECTS OF ACUPUNCTURE AT FENGCHI POINT (GB 20) ON CEREBRAL BLOOD FLOW

Blood velocity in the vertebral artery and the basilar artery was observed before and after acupuncture at Fengchi point (GB 20) in 97 patients by transcranial Doppler ultrasonic detecting. The results showed that the blood velocity in patients with either high or low blood flow had significant changes after acupuncture (P

EFFECTS OF ELECTRO ACUPUNCTURE AND TWIRLING REINFORCING-REDUCING MANIPULATIONS ON VOLUME OF MICROCIRCULATORY BLOOD FLOW IN CEREBRAL PIA MATER

Effects of electroacupuncture (EA) and routine acupuncture with twirling reinforcing and reducing manipulation of the needle (RA) both at Zusanli point (St 36) on volume of microcirculatory blood flow in the cerebral pia mater were observed by fenestration of the cranial bone and laser Doppler microcirculatory blood flow analyser. Results showed that both RA and EA could increase the volume of microcirculatory blood flow in the cerebral pia mater; and that the increase in the EA group was superior to that in RA group. This suggests that a moderate and effective stimulation is a key to the production of a regulative effect on the organism.

颈总动脉流速对创伤合并休克患者容量反应性的评价

目的探讨颈总动脉呼气末及吸气末流速对评估创伤合并休克患者容量反应性的意义。方法前瞻性研究2017年7月—2019年1月上海市浦东新区人民医院重症监护室收治需要机械通气控制呼吸的创伤合并休克患者60例,根据液体复苏后是否具有容量反应性(VR)且扩容前后心输出量(CO)变化是否≥15%将患者分为有反应(VR+组)及无反应(VR-组),各30例。VR+组男性23例,女性7例;年龄18~86岁,平均46.9岁。VR-组男性21例,女性9例;年龄18~90岁,平均46.1岁;采用迈瑞M9便携式多普勒超声取右颈总动脉长轴方向上测量两组患者呼气末最大血流速度(ex-Vmax)、吸气末最大血流速度(in-Vmax)与呼气末平均血流流速(ex-TAmax)、吸气末平均血流流速(in-TAmax),并计算出各自的变异度值:颈总动脉吸呼气末最大血流速度变异度(△Vmax)、吸呼气末平均血流速度变异度(△TAmax),分析不同组别上述数值的变化;绘制受试者工作特征(ROC)曲线,分析以上各项指标在容量反应性评估方面的价值。结果VR+组与VR-组in-Vmax[(71.72±18.67)cm/s vs.(79.47±24.04)cm/s]、in-TAmax[(40.67±11.44)cm/svs.(46.44±15.84)cm/s]比较无明显差异,但ex-Vmax[(61.00±17.84)cm/s vs.(76.86±25.28)cm/s]、ex-TAmax[(34.83±11.01)cm/s vs.(44.66±15.43)cm/s]比较差异有统计学意义(P<0.05)。VR+组与VR-组△Vmax(19.42%±14.18%vs.5.09%±13.59%)、△TAmax(18.19%±11.63%vs.4.29%±7.57%)比较差异有统计学意义(P<0.001)。ex-Vmax与ex-TAmax对创伤合并休克患者容量评估的ROC曲线下面积分别为0.695和0.678,而△Vmax与△TAmax的ROC曲线下面积均>0.800,分别是0.803和0.863,提示△Vmax、△TAmax对于创伤合并休克患者容量的评估更敏感。结论呼气末颈总动脉最大血流流速及平均血流流速、吸呼气末最大血流流速差异度及平均血流流速变异度均可用来评估机械通气创伤合并休克患者的容量反应性,且吸呼气末最大血流流速变异度及平均血流流速变异度对容量反应性的评估效果更佳。

基于多频脉冲采样的血流速度估计方法

传统双模超声技术相较于新兴技术更具实现可穿戴化的潜力。在进行脉冲多普勒血流速度估计时,双模超声需同时发射B模式脉冲进行成像定位,这要求B模式脉冲和多普勒脉冲共享采样时间。采用基于单频多普勒脉冲的稀疏间隔发射方式可以解决这一问题,但常见的稀疏发射排布方式(如嵌套发射、互质发射等)存在采样时间窗较长的缺点,特别是在血流速度变化明显的情况下存在时间分辨率不足的问题。此外,长时间窗包含了较多的血流速度分量,容易由于稀疏采样引起伪影,从而影响血流速度估计的准确性。因此,文中提出了一种基于多频脉冲采样的新型血流速度估计方法。首先,构建了多频脉冲采样的回波模型,并对该模型进行推导,证明了在频率衰减平稳假设下,该数学模型等价于单频多普勒脉冲稀疏发射方式,即多频脉冲采样可以通过较短的时间窗实现类似于基于单频脉冲采样模式的长时间窗的性能,从而提高血流速度谱的时间分辨率和估计精度;然后,提出了两种可用于多频脉冲采样模式的血流速度谱的构建方法,分别为复杂度较低的BMUSIC算法和伪影抑制效果较佳的VMUSIC算法。基于FieldⅡ仿真数据和人体实测数据的实验结果表明:相较于单频多普勒脉冲稀疏发射方式,文中方法不仅可以采用较短的时间窗提升血流速度谱的时间分辨率,还可以获得连续、清晰、精度较高且伪影抑制效果较佳的血流速度估计结果;在人体实测数据实验中,由于实验条件所限,文中方法无法实现非整数倍频,未能充分展现VMUSIC算法的性能优势。

体检人群中超重和肥胖对基底动脉、颈内动脉和椎动脉功能的影响

目的探讨健康体检人群中,体质量指数(BMI)与颅内动脉(基底动脉、颈内动脉和椎动脉)功能的相关性。方法回顾性选取2023年6至8月健康体检者共1169例。收集一般资料、实验室指标以及经颅多普勒数据。依据BMI分为3组:正常组(<24 kg/m^(2))546例、超重组(24~<28 kg/m^(2))484例和肥胖组(≥28 kg/m^(2))139例。比较3组临床特征、实验室指标、颅内动脉血流速度情况。分析BMI与颅内动脉血流速度的相关性,利用多元线性回归及限制性立方条分析BMI与颅内动脉血流速度的关系,并确定颅内动脉血流速度减慢风险增加的临界值。结果与正常组相比,肥胖组和超重组颅内动脉收缩期血流速度、舒张期血流速度和平均血流速度均较低(P<0.05)。多元线性回归分析显示,BMI与颅内动脉收缩期血流速度、舒张期血流速度及平均血流速度呈负相关(P<0.01),与血管搏动指数、阻力指数无相关性(P>0.05)。限制性立方条结果显示,基底动脉和双侧椎动脉血流速度与BMI之间呈线性相关(P>0.05),双侧颈内动脉血流速度与BMI之间呈非线性相关(P<0.05)。结论健康体检人群中BMI与颅内动脉血流速度呈负相关,当BMI超过特定值(24.18~24.26 kg/m^(2))时,颅内动脉血流速度减慢的风险增加。

经阴道彩色多普勒超声在子宫内膜病变患者中的应用价值

目的分析经阴道彩色多普勒超声在子宫内膜病变患者中的应用价值。方法选取2021年2月至2022年4月南昌大学第四附属医院收治的88例子宫内膜病变患者作为研究对象,所有患者均接受经阴道彩色多普勒超声及病理学检查,按照病理学检查结果将患者分为息肉组与癌变组,每组44例。比较两组二维超声子宫内膜情况、病灶血流动力学情况、经阴道彩色多普勒超声血流相关参数;以病理学检查结果为金标准,分析经阴道彩色多普勒超声对子宫内膜癌变的诊断效能。结果癌变组子宫内膜厚度厚于息肉组,内膜-肌层分界清晰、病灶回声均匀占比均低于息肉组,差异有统计学意义(P<0.05);癌变组血流丰富占比高于息肉组,差异有统计学意义(P<0.05);癌变组血流阻力指数(RI)、搏动指数(PI)均低于息肉组,时间平均峰值流速(TAP)慢于息肉组,差异有统计学意义(P<0.05);经阴道彩色多普勒超声对子宫内膜癌变的诊断灵敏度为86.36%,特异度为84.09%,准确度为85.23%;诊断息肉的灵敏度为84.09%,特异度为86.36%,准确度为85.23%。结论经阴道彩色多普勒超声对子宫内膜病变的诊断准确率较高,能通过血流动力学、RI、PI、TAP及影像学表现鉴别息肉或癌变。

沙滩椅体位及控制性降压下肩关节手术病人脑氧饱和度与脑部血流速度改变及其对术后神经认知的影响

目的分析沙滩椅体位及控制性降压下肩关节手术中脑氧饱和度(rScO_(2))与脑部血流速度的变化,及其对病人术后神经认知的影响。方法选取拟于本院以沙滩椅体位接受肩关节手术治疗的病人60例,均为美国麻醉医师协会(ASA)分级Ⅰ、Ⅱ级,在静脉全身麻醉及控制性降压干预下,于麻醉前、麻醉并转入沙滩椅体位后5 min、手术开始时以及手术开始后每隔20 min直至手术结束进行rScO_(2)、大脑中动脉血流速度(VMCA)和有创血压(心脏水平和耳道水平)的检测,并记录脑氧欠饱和事件(CDE)的发生。同时,于术前和术后24 h对病人进行神经认知能力测试。结果转入沙滩椅体位后所有病人的rScO_(2)和VMCA相比麻醉前都有所下降。经历CDE的病人耳道水平平均动脉压、rScO_(2)和VMCA均显著低于未经历CDE的病人,并且术后24 h时连线测试成绩也更低,组间差异有统计学意义(P<0.05)。结论对于ASA分级Ⅰ、Ⅱ级病人,沙滩椅体位及控制性降压下肩关节手术中部分病人的rScO_(2)和VMCA较麻醉前显著下降并发生CDE,进而对术后神经认知产生不利影响。

高压氧联合银杏叶提取物治疗老年血管性痴呆疗效观察

目的探讨高压氧联合银杏叶提取物治疗老年血管性痴呆的临床疗效。方法选择2019年1月至2022年12月在郑州市第九人民医院就诊的132例老年血管性痴呆患者为研究对象,采用随机数字表法将患者分为观察组和对照组,每组66例。2组患者均给予常规治疗,在此基础上,对照组患者给予高压氧治疗,每日1次;观察组患者给予高压氧联合银杏叶提取物治疗,每日1次;2组患者均连续治疗1个月。分别于治疗前后采用蒙特利尔认知评估量表(MoCA)和Barthel指数评估2组患者的认知功能和日常生活活动能力,并依据MoCA评分和Barthel指数评估2组患者治疗后的临床疗效。分别于治疗前后采用经颅多普勒超声仪检测2组患者大脑前动脉、大脑后动脉、大脑中动脉及椎动脉平均血流速度等脑血流动力学指标。结果治疗前2组患者MoCA评分及Barthel指数比较差异无统计学意义(P>0.05)。治疗后,2组患者MoCA评分及Barthel指数均高于治疗前(P<0.05),且观察组患者的MoCA评分及Barthel指数显著高于对照组(P<0.05)。治疗后,对照组和观察组患者总有效率分别为84.85%(56/66)和95.45%(63/66),观察组患者总有效率显著高于对照组(χ^(2)=4.181,P<0.05)。治疗前2组患者大脑前动脉、大脑后动脉、大脑中动脉及椎动脉平均血流速度比较差异无统计学意义(P>0.05)。治疗后,2组患者大脑前动脉、大脑后动脉、大脑中动脉及椎动脉平均血流速度大于治疗前(P<0.05),且观察组患者大脑前动脉、大脑后动脉、大脑中动脉及椎动脉平均血流速度大于对照组(P<0.05)。治疗期间对照组和观察组患者总不良反应发生率分别为16.67%(11/66)、18.18%(12/66),2组患者总不良反应发生率比较差异无统计学意义(χ^(2)=0.218,P>0.05)。结论高压氧联合银杏叶提取物可更显著地改善老年血管性痴呆患者脑血流状态和认知功能障碍,提高患者日常生活活动能力,总体疗效好,且安全性高。