Doppler Machine Research Articles

Identification of gas-liquid flow regimes using a non-intrusive Doppler ultrasonic sensor and virtual flow regime maps

The accurate prediction of flow regimes is vital for the analysis of behaviour and operation of gas/liquid two-phase systems in industrial processes. This paper investigates the feasibility of a non-radioactive and non-intrusive method for the objective identification of two-phase gas/liquid flow regimes using a Doppler ultrasonic sensor and machine learning approaches. The experimental data is acquired from a 16.2-m long S-shaped riser, connected to a 40-m horizontal pipe with an internal diameter of 50.4 mm. The tests cover the bubbly, slug, churn and annular flow regimes. The power spectral density (PSD) method is applied to the flow modulated ultrasound signals in order to extract frequency-domain features of the two-phase flow. Principal Component Analysis (PCA) is then used to reduce the dimensionality of the data so as to enable visualisation in the form of a virtual flow regime map. Finally, a support vector machine (SVM) is deployed to develop an objective classifier in the reduced space. The classifier attained 85.7% accuracy on training samples and 84.6% accuracy on test samples. Our approach has shown the success of the ultrasound sensor, PCA-SVM, and virtual flow regime maps for objective two-phase flow regime classification on pipeline-riser systems, which is beneficial to operators in industrial practice. The use of a non-radioactive and non-intrusive sensor also makes it more favorable than other existing techniques.

A Portable, Wireless Photoplethysomography Sensor for Assessing Health of Arteriovenous Fistula Using Class-Weighted Support Vector Machine.

A portable, wireless photoplethysomography (PPG) sensor for assessing arteriovenous fistula (AVF) by using class-weighted support vector machines (SVM) was presented in this study. Nowadays, in hospital, AVF are assessed by ultrasound Doppler machines, which are bulky, expensive, complicated-to-operate, and time-consuming. In this study, new PPG sensors were proposed and developed successfully to provide portable and inexpensive solutions for AVF assessments. To develop the sensor, at first, by combining the dimensionless number analysis and the optical Beer Lambert’s law, five input features were derived for the SVM classifier. In the next step, to increase the signal-noise ratio (SNR) of PPG signals, the front-end readout circuitries were designed to fully use the dynamic range of analog-digital converter (ADC) by controlling the circuitries gain and the light intensity of light emitted diode (LED). Digital signal processing algorithms were proposed next to check and fix signal anomalies. Finally, the class-weighted SVM classifiers employed five different kernel functions to assess AVF quality. The assessment results were provided to doctors for diagonosis and detemining ensuing proper treatments. The experimental results showed that the proposed PPG sensors successfully achieved an accuracy of 89.11% in assessing health of AVF and with a type II error of only 9.59%.

Failure Analysis and Maintenance of PHILPS Color Doppler Machine Hardware and Software

Firstly, the structure and work flow of PHILPS ultrasound machine were analyzed, and the fault of electronic box of PHILPS M2540A and PHILPS HD15T color Doppler ultrasound of the failure of hardware and software are used to analysis the application of circuit principle in the process of maintenance and installation of software operation method, provides the reference for the daily fast repair of B color ultrasonic diagnostic equipment.

Influence of Dietary Patterns and Inflammatory Markers on Atherosclerosis Using Ankle Brachial Index as a Surrogate.

To examine the influence of various dietary patterns on ankle-brachial index (ABI) as a surrogate of atherosclerosis, taking into account serum levels of C-reactive protein (CRP) and factors that predispose to inflammation and/or endothelial damage (homocysteine) or may be protective (tryptophan, vitamin D), as well as age, gender, and lifestyle risk factors. Cross sectional analysis. Cohort of 4000 men and women aged 65 years living in the community in Hong Kong SAR China. Interviewer administered questionnaire that includes dietary intake estimation by the food frequency records (from which various dietary patterns can be characterized), socioeconomic status, smoking habit, alcohol consumption, physical activity. Clinical measurements include body weight and height, and ankle-brachial index using hand-held Doppler machine. Laboratory measurements include assays of serum 25 hydroxyvitamin D, CRP, homocysteine, and tryptophan using LC/MC methods. Compared with the lowest quintile of vitamin D level, higher quintile was associated with lower prevalence of ABI <0.9 in women only after multiple adjustments of covariates. In men the low score group of the vegetables-fruits dietary pattern was associated with increased odds of having ABI<0.9 after adjusting for all covariates (OR=16.51 (95% CI: 2.21, 123.26)). Similar findings apply to the low score group in the MIND (Mediterranean-DASH Intervention for Neurodegenerative Delay Diet) pattern (OR=2.6 (95% CI: 1.24, 5.42)). In women, ABI<0.9 was associated with low Dietary Quality Index (DQI) score (OR=2.05 (95% CI: 1.22, 3.43)), and low score group of snacks-drinks-milk products dietary pattern (OR=3.07 (95% CI: 1.05, 9.04)). No association was observed for the Mediterranean Dietary Pattern (MDS), Dietary Approaches to Stop Hypertension (DASH), Okinawan and "meat-fish" dietary patterns in either men or women. We conclude that any dietary patterns emphasizing fruit and vegetable intake are associated with better vascular health using ABI as an indicator.

Theoretical developments and clinical experiments of measuring blood flow volume (BFV) at arteriovenous fistula (AVF) using a photoplethysmography (PPG) sensor

A new theoretical developments of measuring blood flow volume at arteriovenous fistula (AVF) using a photoplethysmography (PPG) sensor is presented in this work. The mathematical equation is derived under the practical perspective, aiming at applying to small-size, portable, inexpensive and easy-to-use PPG sensor, in order to replace bulky, expensive Doppler machines which is the commonly used instruments for accessing AVF noninvasively nowadays. Furthermore, a new, portable and wireless PPG sensor with ambient light compensation and motion artifact detection, is designed for performing clinical validation of the proposed equation. After neural network calibration with the gold standard, dilution concentration sensor, the experiment result reveals that the PPG sensors implementing the proposed equation successfully achieve much higher correlation (R2 = 0.8064) and much lower error (RMSE = 171.68 ml/min, MAPE = 15.84%) compared to the commercial Doppler machine and other previous works.

The novel ultrasound doppler machine for microembolus detection from the cervical arteries

The novel ultrasound doppler machine for microembolus detection from the cervical arteries

AMNIOTIC FLUID ASSESSMENT;

Objectives: To assess amniotic fluid volume in second and third trimester ofpregnancy in Pakistani population. Period: Three months. Setting: Talha ultrasound, Multan.Material and Methods: I have started my work by collecting data from the month of November,2015 to February, 2016. The machines which have been used for data collection were Xarioand Z-5 ultrasound Doppler machines with transabdominal (3.5-5MHz) probes. A group of 100Pakistani married female patients of different age groups was included. These patients werehaving normal criteria of second and third trimester (14-40 weeks gestational age). Results:100 married female patients were selected having different age group. There were no significantdifference found in the means of large pocket volume and four pocket volumes of second andthird trimester of pregnancy. Conclusion: Ultrasound plays an important role in assessment ofamniotic fluid volume. If there is one unit change in large pocket volume (LPV) than four pocketvolume (FPV) will change by 2.37 and 2.146 in second and third trimester, respectively.

P18.05: Many faces of whirlpool in patients with adnexal torsion

Adnexal torsion is gynecological surgical emergency. Though it is mainly seen in reproductive age group, it can be seen in any age group. Early diagnosis is important to prevent loss of the adnexa / ovary. USG is the modality of choice for diagnosis. Whirlpool sign is the main diagnostic clue to the diagnosis of adnexal torsion and it is important to recognise this sign in its different appearances. We present our data of last 10 years in which there were 41 cases of adnexal torsion. 28 patients showed presence of whirlpool sign. We analysed the ultrasound findings of whirlpool sign in 28 cases. All patients were scanned by transvaginal USG and transrectal USG if unmarried. Patients were scanned on Philips HD11Xe & IU 22 colour Doppler machines. The presence of whirlpool sign, vascularity within the whirlpool, appearance of whirlpool was documented. The age at diagnosis ranged from 4-56 years. Out of 28 cases 16 showed flow within whirlpool, 12 showed no flow within whirlpool. 26 patients were operated and diagnosis confirmed. One patient refused surgery due to pregnancy and one patient was lost to follow up. In 4 patients isolated tubal torsion was found, 12 patients had only ovarian torsion, 9 patients had both ovarian and tubal torsion and in one patient paratubal cyst had undergone torsion (ovary and fallopian tubes were normal). Helpful USG features in diagnosing torsion are enlarged, edematous ovaries, multiple peripheral follicles, presence of concomitant ovarian mass, pelvic fluid, abnormal location of ovaries. Whirlpool sign is very specific for torsion. One should learn to look for different appearances of whirlpool, like-target appearance, either with or without a central echogenic dot; string of hypoechoic beads suggestive of dilated veins; appearance of a snail shell; or just a large hypoechoic mass. Presence of colour signal in whirlpool is important for prognostication. It should be remembered that search for whirlpool, at times can be difficult in presence of large masses and in a patient with pelvic pain.

Carotid tree changes of Maxillofacial Missile injuries by Doppler sonographay - an Iraqi study

Background: Injuries of the carotid artery caused by penetrating wounds of the neck are nearly 10 times as common as those caused by non penetrating trauma (1), over 10% of all penetrating neck wounds result in significant carotid artery(2) ,and more than 90% of such injuries are secondary to gunshot wounds (3). Injuries to the extra cranial carotid arteries from penetrating trauma is more likely to cause a dissection through intimae disruption and subsequent formation of a false channel and thrombus (4).Patients: Patients were selected from Maxillofacial department in the Specialized Surgeries Hospital in Baghdad . thirty patients were examined , twenty nine were male ( mean 96,66% ) ,only one female was examined ( 3,34% ) . We prepared a specially designed case sheet including , life saving procedures , type of missile , clinical examination include site of missile injuries according to Saletta JD et al 1976 (5) who classified the neck Into three zones , investigation X- ray ,C T scan. .The ultrasonographic scanning of the carotid arteries was performed, the Doppler machine was -SIEMENS – sonoline ELEGRA . Using a highfrequency linear array imaging probe or transducer 7,5- 9 ( MHz) with a Hewlett packard scanner.&#x0D; Methods : The ultrasonographic scanning of the carotid arteries was performed with the patient in the supine position , the examination takes 30 to 60 minutes (6,7) . Using a highfrequency= linear array imaging probe (7.5- 9 MHz) .Results : Patients age ranging from 15 – 57 years and the mean was 36 years ,most cases were from age range 20-29 years ( 40%) .Eighteen patients ( 60%) were injured with bullets , twelve were injured with shell fragments ( 40 % ) , twelve ( 40%) were hand gun bullets and six ( 20%) were rifle bullets. Intimae media thicknesses of common carotid arteries were measured .Mean of IMT right was 0.7 mm and left side was 0.71 mm . While IMT of right external carotid artery was 0.71 mm , IMT of left external carotid artery was 0.75 mm . IMT of right internal carotid artery was 0.8 mm ,IMT of left internal carotid artery was 0.78 mm .Results reveled that mean of IMT of Ext. carotid artery at injured side was more thicker ( 0.79 mm) than non injured side and the mean of IMT of common carotid artery was also thicker at injured side 0.8 mm .&#x0D; Conclusion: Ultrasound scanning is noninvasive, and usually painless . , there are no known harmful effects on humans , carotid Ultrasound has to be a risk free procedure . Further Ultrasound scanning gives a clear picture of soft tissues that do not show up well on X- ray images . Mean of IMT of Ext. carotid artery at injured side was more thicker ( 0.79 mm) than non injured side and the mean of IMT of common carotid artery was also thicker at injured side 0.8 mm .

Fetal cardiac functional performance and development of diabetic gestations

Objective of research: To reveal and asses probable change in fetal cardiac physiological function of pregestational diabetic gestations. Research design: We performed a prospective research study of 31 gestations between 22 weeks’ gestational age and full term, and who had pregestational diabetes. All diabetic women recruited in the research performed had glycosylated hemoglobin lower than 6.5%. All gestations involved in the research performed had an early sonographic confirmation of fetal gestational age. Doppler study of blood flow via the fetal mitral and tricuspid valves were performed every 4 weeks using a pulsed wave sonographic Doppler machine with a 3.5- or 5-MHz ultrasound transducer. The subsequent parameters were analysed and calculated automatically from the revealed flow velocity waveforms: the peak velocity during the rapid ventricular filling phase (E wave) and during the atrial systole phase (A wave), and the ratio between these obtained velocities (E/A ratio); and the velocity time fundamental of the fetal atrioventricular blood flow (correlated with volume flow). A comparative statistical analysis between the Doppler parameters revealed from fetal examination of diabetic gestations and of normal gestations was performed by using the Mann-Whitney test. Results: Each gestation recruited for the study performed around four to five fetal echocardiographic Sonographic assessments at 22, 26, 30, 34, and 38 weeks’ gestation. The E/A ratio of the mitral and tricuspid valves did not Rise in fetuses of diabetic women during the third trimester and was observed to be statistically significantly higher manner in fetuses of nondiabetic gestations in comparison with fetuses of diabetic gestations at 34 and 38 gestational weeks. Calculated velocity time basic of the mitral and tricuspid valves when multiplied by fetal heart rate was greater, but not statistically significant, in fetuses of nondiabetic gestations when put in comparison with diabetic gestations fetuses at 34 and 38 weeks’ gestational weeks. The E-wave of both the mitral and tricuspid valves rised in both study categories all the way through pregnancy. The A-wave of the mitral and tricuspid valves rised only in diabetic gestation fetuses all over the final gestational trimester and was statistically significant in a greater manner at 34 and 38 gestational weeks compared with fetuses of nondiabetic women. Conclusion: variability in fetal atrioventricular blood flow forms between fetuses of diabetic gestations and normal gestations does not essentially cause variability in fetal functional cardiac compliance.

A Comparison of Ultrasonic Doppler and Oscillometric Methods in Systemic Blood Pressure Measurement of Dogs

The present study compared two indirect blood pressure methods at thoracic limb, pelvic limb, and coccygeal sites. For measurement of blood pressure, 48 client-owned dogs in a clinical setting were used. When comparing the results obtained by doppler and oscillometric methods, there were significant differences in blood pressure of the thoracic and pelvic limbs. The Doppler machine produced significantly higher blood pressure value than oscillometry measured at thoracic and pelvic limbs. The difference in blood pressure between the two methods was not significant when measured in the tail. Comparison of blood pressure measured at three different sites by doppler, blood pressure measured at pelvic limb was higher than at thoracic limb and tail. In case of oscillometry, there were no significant differences between the three sites. The results of this study indicate that mechanical and positional differences were existed in blood pressure measurements at the canine thoracic limb, pelvic limb and tail.

Hemodynamic Changes in Portal Vein and Frequencies of Acute and Chronic Portal Vein Thrombosis in Pediatric Patients Presenting with Hematemesis

&lt;p&gt;&lt;strong&gt;Objective:&lt;/strong&gt; The objective of the study is to calculate the frequency of portal vein thrombosis in pediatric patients presenting with hematemesis and to estimate the frequency of acute and chronic portal vein thrombosis in these cases.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Patients and Methods:&lt;/strong&gt;&lt;strong&gt; &lt;/strong&gt;Pediatric patients of 1 – 15 years of age of either sex, presenting to emergency or gastroenterology department with complaint of hematemesis were included. Informed consent was taken from parents/guardians. This is a Descriptive cross sectional study conducted in department of pediatric radiology, Children Hospital and Institute of child Health Lahore from 11-12-2012 to 10-6-2013. Doppler ultrasound of these patients was performed at Core Vision pro SSA 350-A Doppler machine (Toshiba, Japan) using standard imaging protocols. The data was analyzed using SPSS version 17.0 (SPSS Inc., IL, Chicago, USA)&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results:&lt;/strong&gt;&lt;strong&gt; &lt;/strong&gt;In this study, 41% (n = 41) between 1 – 5 years, 38% (n = 38) between 6 – 10 years and only 21% (n = 21) between 11 – 15 years of age, 64%( n = 64) were male and remaining 36% (n = 36) were females, frequency of portal vein thrombosis in pediatric patients presenting with hematemesis reveals in 37% (n = 37) while 63% (n = 63) had no findings of PVT, frequency of acute and chronic forms in patients positive for portal vein thrombosis was 40.54% (n = 15) had acute and 59.46% (n = 22) had chronic portal vein thrombosis.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusion:&lt;/strong&gt;&lt;strong&gt; &lt;/strong&gt;We concluded that the frequency of portal vein thrombosis in pediatric patients presenting with hematemesis and frequency of acute and chronic forms in patients positive for portal vein thrombosis is in accordance with other studies while color Doppler ultrasound is a useful diagnostic modality being noninvasive and cost effective.&lt;/p&gt;

Validity, reliability and accuracy of oscillometric devices, compared with Doppler ultrasound, for determination of the Ankle Brachial Index: an integrative review

INTRODUCTION: The conventional method for measuring the ankle-brachial index (ABI) requires a vascular Doppler machine and a trained professional, which is a barrier to the examination becoming more widely adopted across health services. For this reason, the possibility of substituting Doppler monitors for other types of device has been investigated. The objective of this study was to assess the validity, reliability and accuracy of taking ABI measurement using oscillometric devices and compare them to vascular Doppler.METHODS: This is an integrative literature review of four articles.RESULTS: There was very little uniformity between the four studies in terms of ample populations or the methodological procedures used to measure systolic pressures. The results for sensitivity, specificity and positive and negative predictive values varied and so did measures of reliability.CONCLUSIONS: The results of these studies do not provide a basis from which conclusions can be drawn on the validity, reliability or accuracy of employing oscillometric devices as a substitute for Doppler for determination of ABI.

Assessing the Oldness and Capacity of Radiography and Ultrasound Equipment in Tehran University of Medical Sciences

BackgroundMaintenance of imaging equipment is a very important part of the management of all medical imaging centers.ObjectivesTo assess the oldness and capacity of radiography and ultrasound equipment in Tehran University of Medical Sciences.Materials and MethodsThe study was performed in 16 hospitals, 4 faculties and three healthcare centers of Tehran University of Medical Sciences. We evaluated all the X-ray equipment (including the simple plain and dental, panorex, mammography, fluoroscopy and C-arm X-Ray devices) and also simple and Doppler ultrasound machines in terms of the type and usage of the device, production year, quantity of utilization, location, brand and current condition.ResultsAmong fixed X-ray systems, 15 were currently in use, two were junk, two were damaged, and one was not utilized. The mean (SD) of the usage of these was 2151 (2230) cliché/month, and the mean (SD) of the oldness was 16.9 (13.6) years. The oldness of radiography equipment in our study was more than 20 years in 16, between 11 and 20 in 46, and less than 10 years in 76 devices. The mean (SD) usage (patients/month) of simple and color Doppler devices were 234.1 (365.2) and 597.5 (505.3), respectively. The oldness of ultrasonography equipment in our study was more than 11 years in 12 and less than 10 years in 55 devices. We found that 22 (15.9%) of the radiography systems and two (3%) of the ultrasonography systems had been used for more than 20 years.ConclusionRadiology equipment in Tehran University of Medical Sciences have potential capacity, but they need repair, and better maintenance and management and application of standards for the imaging system needs organized supervisory mechanisms.

SAT0389 Color or power doppler - which is more sensitive and do machine settings matter?

BackgroundThe sensitivity of Doppler to detect slow blood flow in inflamed joints is of utmost importance. This may be influenced by factors such as Doppler modality, machine and settings. Power...

Effects Of Nimodipinee On Cerebral Hemodynamic And Prognosis Of Diffuse Axonal Injury Patients With Repeated Measurements Design

In medical and behavioral researches experimental units, are often the people who are in different social status, physical and other tendency So their responses will be different. In these situations they are required to control the changes in the result of this sources that are potentially variable otherwise the source of variability can increase mean square error significantly and make impossible revealing the real difference between treatments. Appropriate model for such research projects are repeated measurements. This study is a prospective study that accesses the effects of Nimodipinee on Hemodynamic changes of cerebral vessels and the short time prognosis in DAI patients. The study was done in Trauma word of Imam Reza hospital of Tabriz Iran. Forty DAI patients were randomized in two equals groups the case group underwent treatment with Nimodipine drug (every 4 hours after admission) Control groups did not received this treatment. Hemodynamic changes in these patients were measured using transcranial Doppler machine on the first third and tenth days of admission. Using a repeated measurements design fitting model \[Y_{ijk}=\mu+\tau_i+\beta_{j(i)}+\gamma_k+(\tau\gamma)_{ik}+(\beta\gamma)_{kj(i)}+\varepsilon_{m(ijk)}\] In which τi is the drug effect (groups Case and Control) is fixed and is in two levels. \(Β_{j(i)}\) is the effect Of j-th patient in group i, which is in twenty level. \(\gamma_k\) is TCD stages that is fixed and it is in three levels. \((\tau\gamma)_{ik}\) and \((\beta\gamma)_{kj(i)}\) are correspond interactions, this finding obtained that there is no significant differences in Doppler variables between three time TCD and Nimodipine did not make significant difference between the variables. In this study using Nimodipine in DAI patients did not make significant effect on Doppler variables. Therefore, using this drug for this group of patients is not recommended.

Ankle Brachial Pressure Index: As a predictor of peripheral arterial disease in diabetic and non diabetic subjects

Background: Peripheral arterial disease is known to be associated with the diabetes and ankle-brachial pressure index (ABPI) can be used to screen such patients having PAD. Aims & Objective: To highlight the application of ankle brachial pressure index as a routine procedure and to assess the feasibility of using ABPI in detecting PAD in the patients of diabetes mellitus. Material and Methods: 30 Diabetic and 30 Non diabetic patients were recruited. Details regarding anthropometric measurements, blood sugar levels, lipid profile, Edinburgh questionnaire, peripheral pulse examinations etc. were filled in preformed questionnaire. Ankle-brachial pressure index (ABPI) was measured with the help of Handheld Doppler machine. Descriptive statistics in the form of frequency and percentage is used for description of data. Chi-square test was used for comparison of events in two groups. Results: PAD was more common in old age but found not to be associated with gender. Body mass index, surface area and wait hip ration was significant more in PAD group as compared to non-PAD. All blood sugar parameters [Fasting blood sugar (FBS), postprandial blood sugar after 2 hours (PP2BS) and Glycosylated haemoglobin (HB1AC)] were significantly more in PAD group as compared to non-PAD. High density lipoprotein was significantly less in PAD group as compared to non-PAD. Triglyceride, Total Cholesterol and Low density lipoprotein was significantly more in PAD group as compared to non-PAD. ABPI was significantly less in diabetics as compared to non-diabetics. More diabetics were in having PAD as compared to non-diabetics. Conclusion: PAD is found to be associated with more weight, adverse lipid profile and diabetes. ABPI can be used to screen the PAD in diabetic patients.

Color Doppler to Characterize Malignant Breast Lesion

Doppler ultrasound is an important non-invasive diagnostic tool for identifying breast diseases. Ultrasound utilizes spectral Doppler techniques for quantitative evaluation of blood flow velocities, and these measurements play a crucial role in the diagnosis. In this paper, we describe a computer vision approach to automate the Doppler malignancy estimation. We present a technique for segmenting blood vessels in ultrasound color Doppler images based on image processing techniques. The technique decomposes a complex object representing either two or more vessels artificially linked together or a main vessel with its branches. We segment out the blood vessels in ultrasound color Doppler images and count the number of vessels to detect breast malignancy. MATLAB has been used to simulate the algorithm and the results obtained are presented in this paper. The result represents distinct vessels that can be used in further object recognition and quantification applications. In the last two decades of the twentieth century, a combination of modern treatment methods and strategies for early detection through screening and better public awareness, have improved survival of breast cancer despite a worldwide rise in its incidence. Different macro imaging like X-Ray mammography, Sono-mammography and Breast MRI play a major role in detection. Sono-mammography is a promising one among them for it is non-invasive and also cost effective for mass screening. Ultrasound imaging systems offer two main image types- gray-scale images and color Doppler images, each of which has its own clinical usage. Gray-scale images are used to visualize the anatomy of different body organs, while color Doppler images are used to visualize the blood flow (1) within the organs. Both images are used simultaneously for diagnosis as shown in Figure 1. To improve the accuracy of USG, additional techniques like Doppler imaging can be used. Doppler ultrasound technique is associated with reflection of continuous ultrasound waves. When an interface has back and forth movement, the transmitter and receiver frequency of the reflected ultrasound wave decreases or increases respectively. Doppler Effect refers to a change in the perceived frequency of sound emitted by a moving source. Doppler machines have the capability to note down the frequency changes. Doppler Effect in reflected wave gives information about the motion of the tissue interfaces. Transducers used for Doppler instruments consist of double-crystal, one transmitter and another receiver. Transmitter generates continuous ultrasound beam and they have no or very little damping material inside. Quantitative blood flow measurement can be done using this technique and it produces 2D images of region where blood-flow or tissue movement is occurring. The cost of this instrument is also very low.

Re: Three‐dimensional power Doppler: validity and reliability

Re: Three‐dimensional power Doppler: validity and reliability

Prevalence and Correlates of Physiological Valvular Regurgitation in Healthy Subjects - A Color Doppler Echocardiographic Study in the Current Era -

Although echo Doppler machines have consistently advanced within a quarter of a century, age related prevalence of valvular regurgitation detected by currently available echo machines remains uncertain. The aim of this study was to investigate the prevalence and correlates of valvular regurgitation in healthy individuals. A total of 1,333 apparently healthy individuals were enrolled in this study. Echocardiographic examinations were performed using a currently available echo machine. Aortic regurgitation (AR) was detected less frequently (<10%) in younger subjects. Prevalence of aortic regurgitation increased with advancing age and reached 46% in their 9th decade. Mitral regurgitation (MR) was detected in two-thirds of the subjects >30 years old. Tricuspid regurgitation (TR) was frequently (>80%) detected in all age groups. In general, prevalence of valvular regurgitation was higher than those reported previously, except for a relatively lower prevalence of AR in the elderly population. Age was an independent correlate of AR and MR, but not of TR. The presence of AR and MR were independent correlates of TR. In healthy subjects, AR, MR or TR are commonly detected by using a current echo machine. These "physiological" valvular regurgitations should not be considered as a "pathological" valvular heart disease.