A Virtual Instrument for Automated Measurement of Arterial Compliance

2010 ◽  
Vol 4 (4) ◽  
Author(s):  
Jayaraj Joseph ◽  
V. Jayashankar
Keyword(s):  
Virtual Instrument ◽  
Arterial Compliance ◽  
Single Element ◽  
Prototype System ◽  
Automated Measurement ◽  
General Medical Practitioner ◽  
Arterial Distensibility ◽  
Minimal Operator ◽  
Vascular Ultrasonography ◽  
Better Than

Measurement of arterial distensibility is very important in cardiovascular diagnosis for early detection of coronary heart disease and possible prediction of future cardiac events. Conventionally, B-mode ultrasound imaging systems have been used along with expensive vessel wall tracking systems for estimation of arterial distension and calculation of various estimates of compliance. We present a simple instrument for noninvasive in vivo evaluation of arterial compliance using a single element ultrasound transducer. The measurement methodology is initially validated using a proof of concept pilot experiment using a commercial ultrasound pulser-receiver. A prototype system is then developed around a PXI chassis using LABVIEW software. The virtual instrument employs a dynamic threshold algorithm to identify the artery walls and then utilizes a correlation based tracking technique to estimate arterial distension. The end-diastolic echo signals are averaged to reduce error in the automated diameter measurement process. The instrument allows automated measurement of the various measures of arterial compliance with minimal operator intervention. The performance of the virtual instrument was first analyzed using simulated data sets to establish the maximum measurement accuracy achievable under different input signal to noise ratio (SNR) levels. The system could measure distension with accuracy better than 10 μm for positive SNR. The measurement error in diameter was less than 1%. The system was then thoroughly evaluated by the experiments conducted on phantom models of the carotid artery and the accuracy and resolution were found to meet the requirements of the application. Measurements performed on human volunteers indicate that the instrument can measure arterial distension with a precision better than 5%. The end-diastolic arterial diameter can be measured with a precision better than 2% and an accuracy of 1%. The measurement system could lead to the development of small, portable, and inexpensive equipment for estimation of arterial compliance suitable in mass screening of “at risk” patients. The automated compliance measurement algorithm implemented in the instrument requires minimal operator input. The instrument could pave the way for dedicated systems for arterial compliance evaluation targeted at the general medical practitioner who has little or no expertise in vascular ultrasonography.

Vascular Ca overload produced by vitamin D3 plus nicotine diminishes arterial distensibility in rats

1994 ◽  
Vol 266 (2) ◽  
pp. H540-H547 ◽  
Author(s):  
J. Atkinson ◽  
P. Poitevin ◽  
J. M. Chillon ◽  
I. Lartaud ◽  
B. Levy
Keyword(s):  
Vitamin D3 ◽  
Structural Changes ◽  
Arterial Compliance ◽  
Linear Regression Analysis ◽  
Characteristic Impedance ◽  
Calcium Overload ◽  
Suitable Model ◽  
Plasma Parameters ◽  
Arterial Distensibility ◽  
Young Rats

In humans, aging produces many structural changes in blood vessels, one of the most pronounced being arterial calcium overload. Simultaneously arteries become increasingly rigid. The slow evolution of the two processes renders it difficult to evaluate the importance of vascular calcium overload in the development of decreased compliance. To gain insight into this relationship, rapid vascular calcium overload was produced by treating young rats with vitamin D3 and nicotine. When rats were allowed 16 days or longer to recover from such treatment, analysis of plasma parameters revealed no overt toxicity, and growth rate was similar to that of controls. Pronounced calcium overload was seen primarily in compliance arteries. Changes in systemic arterial compliance, characteristic impedance, pulse-wave velocity, and carotid compliance all reflected a substantial increase in arterial rigidity. Linear regression analysis revealed significant correlations between the various indicators of arterial distensibility and arterial calcium content. In conclusion, treatment of young rats with vitamin D3 and nicotine may provide a suitable model with which to investigate how calcium overload is involved in the induration of compliance arteries.

Role of adrenergic tone in mechanical and functional properties of carotid artery during aging

1993 ◽  
Vol 265 (4) ◽  
pp. H1132-H1138 ◽  
Author(s):  
A. Benetos ◽  
F. Huguet ◽  
P. Albaladejo ◽  
A. M. Brisac ◽  
M. Pappo ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Arterial Compliance ◽  
Structural Parameter ◽  
Cross Sectional ◽  
Arterial Distensibility ◽  
Beta Adrenoceptor ◽  
Alpha Blockade ◽  
The Media ◽  
Carotid Arterial

The present study was designed to assess the role of the adrenergic tone in the regulation of carotid arterial compliance during aging. An experimental model of in situ isolated carotid arteries has been used to evaluate the elastic properties of the arterial wall in young (3-mo-old) and older (18-mo-old) Wistar rats. Binding experiments were performed in the same strain of rats to evaluate alpha 1- and beta-adrenoceptor affinity and density. In a third set of experiments, structural parameter of the carotid artery in younger and older rats was evaluated. Arterial distensibility (compliance per unit of volume) was significantly lower in older rats. This was associated with a significant thickness of the media (45.6 +/- 2.8 vs. 57.5 +/- 5.7 microns, P < 0.01) and increased collagen content in older rats (4,420 +/- 310 vs. 7,320 +/- 850 microns 2/mm, P < 0.001). However, carotid arterial compliance was not altered in older rats because of the significant increase in cross-sectional area with aging. Aging did not affect alpha 1-adrenoceptor affinity and density, whereas it decreased beta-density without changing their affinity. Pharmacological stimulation of alpha 1-adrenoceptor with phenylephrine (10(-5) M) decreased compliance in older but not in younger animals. Blockade of these receptors with prazosin or labetalol increased compliance in younger and had no effect on older rats. beta-receptor stimulation with isoproterenol or blockade with propranolol had no effect in any of the studied groups. We suggest that with aging there is an increased vasoconstricting effect of alpha-agonists and a decreased vasodilatative action of alpha-blockade.(ABSTRACT TRUNCATED AT 250 WORDS)

Implementation of an Intelligent Integrated Detection System Based on Virtual Instrument for Different Missiles

2012 ◽  
Vol 490-495 ◽  
pp. 1063-1065 ◽  
Author(s):  
Xiao Long Zhang ◽  
Zhi Min Yao ◽  
Hong Yun Wang
Keyword(s):  
Virtual Instrument ◽  
Signal Analysis ◽  
Detection System ◽  
Test System ◽  
Software Implementation ◽  
Prototype System ◽  
Practical Applications ◽  
Automatic Test System ◽  
Instrument Technology ◽  
Integrated Detection

Aiming at the intelligent integrated detection System for test and measurement of many different missiles, utilizing the data acquisition technology, virtual instrument technology and signal analysis technology synthetically, in this paper, we introduced the system architecture and accomplished the hardware design and software implementation. Practical applications of the prototype system have proven that this intelligent integrated detection system has more powerful functions, better interaction and more convenient operation than the traditional automatic test system(ATS), it have met the needs of test and measurement of several different missiles

Alteration of the pulsatile load in the high-altitude calf model of pulmonary hypertension

1991 ◽  
Vol 70 (2) ◽  
pp. 859-868 ◽  
Author(s):  
B. D. Zuckerman ◽  
E. C. Orton ◽  
K. R. Stenmark ◽  
J. A. Trapp ◽  
J. R. Murphy ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Right Ventricular ◽  
High Altitude ◽  
Arterial Wall ◽  
Arterial Compliance ◽  
Arterial Elasticity ◽  
Arterial Distensibility ◽  
Pulmonary Arterial ◽  
Pulsatile Load ◽  
The Right

We compared main pulmonary arterial elasticity and global pulmonary arterial compliance in control and high-altitude (HA) calves to determine whether 1) changes in pulmonary arterial elasticity are contributing to an increase in the oscillatory load of the right ventricle in this model of pulmonary hypertension and 2) measured changes in stiffness of the HA calves' arterial wall are the result of both an increase in pressure and an alteration of the material properties of the HA calves' arterial wall. Newborn calves were placed at 4,300 m simulated altitude for 14 days, and control calves were kept at 1,500 m. The HA calves were then reacclimatized to 1,500 m for 24 h so that baseline pressures of the two groups were similar. Open-chest main pulmonary arterial and right ventricular micromanometric pressures, ultrasonic main pulmonary arterial diameter, and green dye flow were measured under baseline conditions and then under moderate and severely hypoxic conditions to make measurements at both baseline and increased pulmonary pressures. At elevated pressures, the pressure-diameter relationship was noted to be nonlinear, and a characteristic late systolic peaking of the right ventricular pressure waveform was seen. The Peterson pressure-strain modulus, pulse wave velocity, characteristic impedance, and global compliance (3 element windkessel) were calculated. The calculated variables were all shown to be pressure dependent, and no intrinsic differences in stiffness were seen between the control and HA animals when mean pressure was taken into account. Pulmonary arterial histology demonstrated, however, a characteristic increase in wall thickness in the HA animals. Thus, in this model of pulmonary hypertension, major changes in elasticity and pulsatile load are primarily due to an increase in pulmonary pressure. The structural changes present in the HA calves' arterial wall did not separately produce any measurable changes in arterial distensibility or the oscillatory load.

Relationship of Age and Blood Pressure to Baroreflex Sensitivity and Arterial Compliance in Man

1976 ◽  
Vol 51 (s3) ◽  
pp. 357s-360s ◽  
Author(s):  
O. S. Randall ◽  
M. D. Esler ◽  
G. F. Bulloch ◽  
A. S. Maisel ◽  
C. N. Ellis ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Negative Correlation ◽  
Baroreflex Sensitivity ◽  
Arterial Compliance ◽  
Significant Negative Correlation ◽  
Arterial Distensibility ◽  
Blood Pressures ◽  
Relationship Of ◽  
The Relationship

1. The relationship between baroreflex sensitivity (BRS) and arterial compliance index (ACI) has been investigated (a) in paired subjects matched in one instance for systolic blood pressure with differing ages, and (b) in another instance matched for age with differing systolic blood pressures. 2. There was a significant negative correlation between BRS and age and between ACI and age in the twelve systolic blood pressure-matched subjects. 3. A significant negative correlation of systolic blood pressure with both BRS and ACI was observed in the fourteen age-matched subjects. 4. Both BRS and ACI appear to decrease with increasing age and systolic blood pressure. This decrease in BRS is probably due at least in part to the observed reduction in arterial distensibility.

scholarly journals Arterial Distensibility in Chronic Inflammatory Rheumatic Disorders

2010 ◽  
Vol 4 (1) ◽  
pp. 83-88 ◽  
Author(s):  
Mustafa Yildiz
Keyword(s):  
Lupus Erythematosus ◽  
Inflammatory Diseases ◽  
Arterial Compliance ◽  
Coronary Perfusion ◽  
Large Artery ◽  
Arterial Distensibility ◽  
Inflammatory Conditions ◽  
Arterial Blood ◽  
Mediterranean Fever ◽  
Peripheral Arterial

The pulse wave velocity (PWV), as an indicator of arterial distensibility, may play an important role in the stratification of patients based on the cardiovascular risk. PWV inversely correlates with arterial distensibility and relative arterial compliance. Decreased arterial distensibility alters arterial blood pressure and flow dynamics, and disturbes coronary perfusion. Systemic immune and inflammatory diseases, such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) are associated with increased morbidity and mortality, predominantly due to adverse cardiovascular events. Systemic inflammation in these disorders may alter arterial compliance and arterial distensibility and, through this effect, lead to accelerated atherosclerosis. We have demonstrated an increase in the carotid-femoral (aortic) PWV that is a technique in which large artery elasticity is assessed from analysis of the peripheral arterial waveform, in patients with chronic inflammatory conditions such as RA, SLE, familial Mediterranean fever (FMF), Wegener’s granulomatosis (WG), sarcoidosis, psoriasis and psoriatic arthritis except Behçet’s disease (BD). In this review, the issue of arterial stiffness in RA, SLE, as well as WG, psoriasis, FMF, BD, sarcoidosis, systemic sclerosis (SS) and Takayasu's arteritis (TA) is overviewed.

scholarly journals Design and parametric evaluation of UWB antenna for array arrangement

2019 ◽  
Vol 8 (2) ◽  
pp. 644-652 ◽  
Author(s):  
Faraz Ahmed Shaikh ◽  
Sheroz Khan ◽  
A H. M. Zahirul Alam ◽  
Dominique Baillargeat ◽  
Mohamed Hadi Habaebi ◽  
...  
Keyword(s):  
Structural Design ◽  
Simulation Software ◽  
Single Element ◽  
Frequency Range ◽  
Uwb Antenna ◽  
Laminate Material ◽  
Array Configuration ◽  
Simulation Results ◽  
Vivaldi Antenna ◽  
Better Than

This paper has introduced the concept of UWB antenna in array arrangements. The four elements of Balance Antipodal Vivaldi Antenna (BAVA) has been used for planar and H-plane array configuration in this research. Each single element of BAVA Antenna is printed on the glass-reinforced epoxy laminate material (FR4) along an overall thickness of 1.57mm and εr=4.3 respectively. The optimized measurement of each particular element is 60.75mm x 66mm approximatel. Further the parametric evaluation of four BAVA elements in different planes has been observed in this paper. The placement of array elements has almost coverd entire UWB frequency range and appropriate reflection coefficient which is better than -10dB has been established in both combinations. According to simulation results, the array elements in planar arrangement presenting a suitable reflection and works well at 3.2GHz frequency while the arrangement in H-plane the array elements works well at 7GHz of frequency. In planar arrangement, the operating frequency of antenna elements is shifting as results of the distance among inter elements which increase in wavelength. In H-plane arrangement an antenna elements generate additional gain up to 10.2 dB with good radiation patterns as compared to the planar plane. The CSTMWS simulation software has been used for antenna structural design and parametric verification.

scholarly journals Synthetic aperture imaging in acoustic microscopy

2021 ◽  
Author(s):  
Golafsoun Ameri
Keyword(s):  
Image Resolution ◽  
Acoustic Microscopy ◽  
Synthetic Aperture ◽  
Lateral Resolution ◽  
Depth Of Field ◽  
Single Element ◽  
Focal Region ◽  
Array Transducer ◽  
Small Depth ◽  
Better Than

Acoustic microscopy (AM) provides micro-meter resolution using a highly focused single-element transducer. A drawback in AM is a relatively small depth of field, resulting in poor resolution outside the focus. Synthetic aperature focusing technique (SAFT) can be used to improve the image resolution throughout the field of view. SAFT mathematically synthesizes the effect of an array transducer and produces dynamic focusing and depth-independent resolution. SAFT in time domain with and without apodization, TD-SAFT and ATD-SAFT, respectively, and in frequency domain (FD-SAFT) were implemented and tested using simulated and experimental radio-frequency data from an acoustic microscope at 400 MHz. Lateral resolution of all the SAFT reconstructed images were better than those of the conventional B-mode images. While TD-SAFT and FD-SAFT permformed better than ATD-SAFT in improving the lateral resolution, ATD-SAFT provided lower side lobes. In conclusion, SAFT improves resolution in AM outside the focal region.

A novel precision bender system for focusing mirrors

2010 ◽  
Vol 1 (MEDSI-6) ◽  
Author(s):  
E. Trakhtenberg ◽  
J. Collins ◽  
O. Schmidt
Keyword(s):  
Synchrotron Radiation ◽  
System Design ◽  
Atmospheric Pressure ◽  
Small Diameter ◽  
Stepper Motor ◽  
Prototype System ◽  
Test Results ◽  
Design Changes ◽  
Photon Source ◽  
Better Than

A novel mirror bender system utilizing cam-shaft mover (CSM) with 100 µm eccentricity was designed and successfully tested. The system was initially tested and characterized in the laboratory, and then later the performance was verified using the Advanced Photon Source synchrotron radiation source. The force from the two separate CSMs is translated to both ends of a mirror through a small-diameter bellows feed-through. The system uses an internal spring assembly to compensate for atmospheric pressure. A compact gear box with 10:1 ratio between the stepper motor and cam shaft is used to increase the precision of the bender system. This bender system is equipped with a precise rotary potentiometer and load cell for feedback. A system resolution better than 0.2 µm per step was achieved. This bender system was designed as a separate unit, is very compact and can be used to bend a mirror in both the vertical and horizontal planes. Details of the system design, changes made from the prototype system to the production unit and test results are presented here.

Association of Circulating Extracellular Matrix Components with Central Hemodynamics and Arterial Distensibility of Peripheral Arteries

2021 ◽  
pp. 1-9
Author(s):  
Vladimir N. Melnikov ◽  
Lena B. Kim ◽  
Anna N. Putyatina ◽  
Sergey G. Krivoschekov
Keyword(s):  
Matrix Metalloproteinase ◽  
Augmentation Index ◽  
Arterial Compliance ◽  
Applanation Tonometry ◽  
Collagen Type Iv ◽  
Peripheral Arteries ◽  
Arterial Distensibility ◽  
Type Iv ◽  
Matrix Metalloproteinase 1 ◽  
Extracellular Matrix Components

<b><i>Background:</i></b> In addition to neuronal and endothelial regulators of vascular tone, the passive mechanical properties of arteries, determined by the molecular structure of extracellular matrices, are the principle modulators of vascular distensibility. Specifically, the association between collagen type IV (Col IV), a constituent of basement membrane, and arterial compliance remains unclear. <b><i>Methods:</i></b> In 31 healthy adult men, radial applanation tonometry and pulse wave analysis were used to assess aortic augmentation index (AIx), aortic-to-radial pulse pressure amplification (PPAmpl), and time to reflection wave. <b><i>Results:</i></b> Plasma Col IV and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) concentrations were correlated with AIx (<i>r</i> = 0.51, <i>p</i> = 0.021 and <i>r</i> = −0.45, <i>p</i> = 0.042, respectively) after adjustment for age and heart rate (HR). Greater matrix metalloproteinase-9 (MMP-9) and TIMP-1 levels were associated with high PPAmpl (<i>r</i> = 0.45 and <i>r</i> = 0.64, respectively) and hence with compliant arteries. Multiple regression analyses revealed that 99% of the variation in PPAmpl was attributable to age, HR, Col IV, TIMP-1, and Col × TIMP-1 interaction (<i>p</i> &#x3c; 0.001). No relations between tonometric variables and levels of MMP-1, -2, and -3; TIMP-2 and -4; fibronectin; glycosaminoglycans; and hydroxyproline were found. <b><i>Conclusion:</i></b> High circulating Col IV level indexes were associated with stiffer peripheral arteries whereas increased MMP-9 and TIMP-1 concentrations were associated with more compliant ones.

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