Read by QxMD icon Read

Doppler velocimetry

Vrishank Raghav, Sudeep Sastry, Neelakantan Saikrishnan
Experimental flow field characterization is a critical component of the assessment of the hemolytic and thrombogenic potential of heart valve substitutes, thus it is important to identify best practices for these experimental techniques. This paper presents a brief review of commonly used flow assessment techniques such as Particle image velocimetry (PIV), Laser doppler velocimetry, and Phase contrast magnetic resonance imaging and a comparison of these methodologies. In particular, recommendations for setting up planar PIV experiments such as recommended imaging instrumentation, acquisition and data processing are discussed in the context of heart valve flows...
March 12, 2018: Cardiovascular Engineering and Technology
R A J Wain, D J Smith, D R Hammond, J P M Whitty
Arterial thrombus formation is directly related to the mechanical shear experienced by platelets within flow. High shear strain rates (SSRs) and large shear gradients cause platelet activation, aggregation and production of thrombus. This study, for the first time, investigates the influence of pulsatile flow on local haemodynamics within sutured microarterial anastomoses. We measured physiological arterial waveform velocities experimentally using Doppler ultrasound velocimetry, and a representative example was applied to a realistic sutured microarterial geometry...
March 6, 2018: Microvascular Research
Rafi Sheikh, Khashayar Memarzadeh, Christian Torbrand, Jonas Blohmé, Sandra Lindstedt, Malin Malmsjö
Purpose: The eyelid is commonly dissected and divided in the process of, for example, blepharotomy, entropion repair, or when preparing a full-thickness eyelid flap to reconstruct a tumor defect. No study has yet been conducted to examine how perfusion in an eyelid is affected by dissection, using modern imaging techniques. Methods: The eyelid was divided with a 10-mm vertical incision, 5 mm from the medial canthus, and the incision was extended horizontally by 30 mm to provide a full-thickness eyelid. Blood perfusion was measured along the length of the free dissected eyelid using both laser Doppler velocimetry and laser speckle contrast imaging...
2018: Eplasty
Justin R Lappen, Stephen A Myers, Norman Bolden, Ziad Shaman, Venkata Angirekula, Edward K Chien
BACKGROUND: Narrow pulse pressure has been demonstrated to indicate low central volume status. In critically ill patients, volume status can be qualitatively evaluated using Doppler velocimetry to assess hemodynamic changes in the carotid artery in response to autotransfusion with passive leg raise (PLR). Neither parameter has been prospectively evaluated in an obstetric population. The objective of this study was to determine if pulse pressure could predict the response to autotransfusion using carotid artery Doppler in healthy intrapartum women...
March 1, 2018: Anesthesia and Analgesia
Tawana Vicente Bertagnolli, Michelle de Souza Rangel Machado, Cristine Jorge Homsi Ferreira, Jackeline de Souza Rangel Machado, Geraldo Duarte, Ricardo Carvalho Cavalli
OBJECTIVE: To assess the feasibility and safety of a physiotherapy protocol applied to pregnant women with preeclampsia. METHODS: Randomized, controlled, single-blind feasibility study, with 24 hospitalized pregnant women with preeclampsia. The intervention group received one session of the physiotherapy. The control group remained under the routine care of the hospital. The primary outcomes were Doppler velocimetry, cardiotocography, and maternal-fetal hemodynamics...
March 1, 2018: Hypertension in Pregnancy
Sabino J Pietrangelo, Hae-Seung Lee, Charles G Sodini
OBJECTIVE:  Practical deficiencies related to conventional transcranial Doppler (TCD) sonography have restricted its use and applicability. This work seeks to mitigate several such constraints through the development of a wearable, electronically steered TCD velocimetry system, which enables noninvasive measurement of cerebral blood flow velocity (CBFV) for monitoring applications with limited operator interaction. MATERIALS AND METHODS: A highly-compact, discrete prototype system was designed and experimentally validated through flow phantom and preliminary human subject testing...
2018: Acta Neurochirurgica. Supplement
Richard Nauber, Lars Büttner, Kerstin Eckert, Jochen Fröhlich, Jürgen Czarske, Sascha Heitkam
The flow field of moving foams is relevant for basic research and for the optimization of industrial processes such as froth flotation. However, no adequate measurement technique exists for the local velocity distribution inside the foam bulk. We have investigated the ultrasound Doppler velocimetry (UDV), providing the first two-dimensional, non-invasive velocity measurement technique with an adequate spatial (10mm) and temporal resolution (2.5Hz) that is applicable to medium scale foam flows. The measurement object is dry aqueous foam flowing upward in a rectangular channel...
January 2018: Physical Review. E
M Rial-Crestelo, R J Martinez-Portilla, A Cancemi, J Caradeux, L Fernandez, A Peguero, E Gratacos, Francesc Figueras
OBJECTIVES: To determine the added value of cerebroplacental ratio (CPR) and uterine Doppler velocimetry at third trimester scan in an unselected obstetric population to predict smallness and growth restriction. METHODS: We constructed a prospective cohort study of women with singleton pregnancies attended for routine third trimester screening (32 +0 -34 +6 weeks). Fetal biometry and fetal-maternal Doppler ultrasound examinations were performed by certified sonographers...
February 15, 2018: Journal of Maternal-fetal & Neonatal Medicine
Francesc Figueras, Javier Caradeux, Fatima Crispi, Elisenda Eixarch, Anna Peguero, Eduard Gratacos
By consensus, late fetal growth restriction is that diagnosed >32 weeks. This condition is mildly associated with a higher risk of perinatal hypoxic events and suboptimal neurodevelopment. Histologically, it is characterized by the presence of uteroplacental vascular lesions (especially infarcts), although the incidence of such lesions is lower than in preterm fetal growth restriction. Screening procedures for fetal growth restriction need to identify small babies and then differentiate between those who are healthy and those who are pathologically small...
February 2018: American Journal of Obstetrics and Gynecology
Islam A Ramadan, Hélène Bailliet, Jean-Christophe Valière
The influence of both the natural convection and end-effects on Rayleigh streaming pattern in a simple standing-wave thermoacoustic engine is investigated experimentally at different acoustic levels. The axial mean velocity inside the engine is measured using both Laser Doppler Velocimetry and Particle Image Velocimetry. The mean flow patterns are categorized in three different regions referred to as "cold streaming" region, "hot streaming" region, and "end-effects" region. In the cold streaming region, the dominant phenomenon is Rayleigh streaming and the mean velocity measurements correspond well with the theoretical expectations of Rayleigh streaming at low acoustic levels...
January 2018: Journal of the Acoustical Society of America
Ibukun A Abidoye, Oluwagbemiga O Ayoola, Bukunmi M Idowu, Adeniyi S Aderibigbe, Olabisi M Loto
Aim of the study: To evaluate the value of uterine artery Doppler indices and waveform pattern in predicting fetuses at risk for intrauterine growth restriction in hypertensive disorders of pregnancy. Materials and methods: This was a prospective cross-sectional study including 80 pregnant subjects with hypertensive disorders of pregnancy and two control groups. Uterine artery Doppler sonography was performed in all study participants. Uterine artery Doppler indices across the groups were compared using the analysis of variance (ANOVA) while the presence of prediastolic notch was analyzed with the Chi Square test...
December 2017: Journal of Ultrasonography
Marie-Elaine Demers, Samuel Dubé, Mélodie Bourdages, Cedric Gasse, Amélie Boutin, Mario Girard, Emmanuel Bujold, Suzanne Demers
OBJECTIVES: To compare the first-trimester uterine artery pulsatility index (PI) measured by abdominal and transvaginal ultrasound (US). METHODS: We performed a prospective study of singleton pregnant women recruited at 11 to 13 weeks' gestation. The mean uterine artery PI was obtained by abdominal followed by transvaginal US. The mean of the left and right uterine artery PIs was used, and differences between approaches were computed. The intraclass correlation coefficient and a Bland-Altman plot were used to compare the two approaches...
January 10, 2018: Journal of Ultrasound in Medicine: Official Journal of the American Institute of Ultrasound in Medicine
Olaide Ashimi Balogun, Raminder K Khanagura, Heather R Kregel, Farah H Amro, Baha M Sibai, Suneet P Chauhan
OBJECTIVE:  The objective of this study was to compare adverse pregnancy outcomes between fetuses with estimated fetal weight (EFW) < 10 to > 10% in women with preterm preeclampsia (PE) with severe features. MATERIALS AND METHODS:  All women with preterm PE with severe features and nonanomalous singletons with EFW were identified at a tertiary center. Women with oligohydramnios or absent/reversed umbilical Doppler velocimetry were excluded. Using multivariable analysis, we compared the composite maternal and neonatal morbidities (CMM and CNM) between those with appropriate for gestational age (AGA) fetal growth, defined as EFW at 10 to 90th versus those with fetal growth restriction (FGR), defined as EFW < 10th percentile for gestational age (GA)...
January 3, 2018: American Journal of Perinatology
Sang Joon Lee, Jun Hong Park, Jeong Ju Kim, Eunseop Yeom
Venous valve dysfunction and induced secondary abnormal flows are closely associated with venous diseases. Thus, detailed analysis of venous valvular flow is invaluable from biological and medical perspectives. However, most of the previous studies on venous perivalvular flows were based on qualitative analysis. On the contrary, quantitative analysis of perivalvular flows has not been fully understood. In this study, we used the ultrasound speckle image velocimetry (SIV) technique, which utilizes the speckle patterns of red blood cells (RBCs) created by ultrasound waves to measure 3-D valvular flows quantitatively...
December 26, 2017: Ultrasound in Medicine & Biology
Paola Algeri, Matteo Frigerio, Maria Lamanna, Petya Vitanova Petrova, Sabrina Cozzolino, Maddalena Incerti, Salvatore Andrea Mastrolia, Nadia Roncaglia, Patrizia Vergani
OBJECTIVE: The aim of the present study was to assess, in a population of dichorionic twin pregnancies with selective growth restriction, the effect of inter-twin differences by use of Doppler velocimetry and fetal growth discordancy on perinatal outcomes. METHODS: This was a retrospective study including dichorionic twin pregnancies from January 2008 to December 2015 at the Department of Obstetrics and Gynecology of Fondazione MBBM. Only dichorionic twin pregnancies affected by selective intrauterine growth restriction (IUGR) delivering at ≥24 weeks were included in the study...
December 29, 2017: Journal of Perinatal Medicine
Francesca Gaccioli, Irving L M H Aye, Ulla Sovio, D Stephen Charnock-Jones, Gordon C S Smith
Fetal growth restriction is a major determinant of perinatal morbidity and mortality. Screening for fetal growth restriction is a key element of prenatal care but it is recognized to be problematic. Screening using clinical risk assessment and targeting ultrasound to high-risk women is the standard of care in the United States and United Kingdom, but the approach is known to have low sensitivity. Systematic reviews of randomized controlled trials do not demonstrate any benefit from universal ultrasound screening for fetal growth restriction in the third trimester, but the evidence base is not strong...
December 22, 2017: American Journal of Obstetrics and Gynecology
Melissa Singletary, Samantha Hagerty, Shin Muramoto, Yasmine Daniels, William A MacCrehan, Gheorghe Stan, June W Lau, Oleg Pustovyy, Ludmila Globa, Edward E Morrison, Iryna Sorokulova, Vitaly Vodyanoy
Olfactory responses are intensely enhanced with the addition of endogenous and engineered primarily-elemental small zinc nanoparticles (NPs). With aging, oxidation of these Zn nanoparticles eliminated the observed enhancement. The design of a polyethylene glycol coating to meet storage requirements of engineered zinc nanoparticles is evaluated to achieve maximal olfactory benefit. The zinc nanoparticles were covered with 1000 g/mol or 400 g/mol molecular weight polyethylene glycol (PEG). Non-PEGylated and PEGylated zinc nanoparticles were tested by electroolfactogram with isolated rat olfactory epithelium and odorant responses evoked by the mixture of eugenol, ethyl butyrate and (±) carvone after storage at 278 K (5 oC), 303 K (30 oC) and 323 K (50 oC)...
2017: PloS One
Morteza Jeyhani, Shahrokh Shahriari, Michel Labrosse
Mitral valve percutaneous edge-to-edge repair (PEtER) is a viable solution in high-risk patients with severe symptomatic mitral regurgitation. However, the generated double-orifice configuration poses challenges for the evaluation of the hemodynamic performance of the mitral valve and may alter flow patterns in the left ventricle (LV) during diastole. This in vitro study aims to evaluate the hemodynamic modifications following a simulated PEtER. A custom-made mitral valve was developed, and two configurations were tested: (i) a single-orifice valve with mitral regurgitation and (ii) a double-orifice mitral valve configuration following PEtER...
November 23, 2017: Artificial Organs
Ulrike H Mitchell, Samantha Burton, Christopher Gordon, Gary W Mack
Objective: To test the hypothesis that long- term aerobically trained elderly individuals have a greater amount of bioavailable nitric oxide (NO) and have a larger cutaneous vasodilation during local heat stress compared to their inactive elderly counterparts. Methods: Eight aerobically trained and 8 inactive older men (>60 years old) participated in this study. NO bioavailability in blood and intradermal dialysate were measured with an ozone based chemiluminescence NO analyzer. Cutaneous vasodilator response to local heating was obtained using laser Doppler velocimetry...
2017: Frontiers in Physiology
Tamara Stampalija, Lorenzo Monasta, Daniela D Di Martino, Mariachiara Quadrifoglio, Leila Lo Bello, Giuseppina D'Ottavio, Sara Zullino, Cristina Mastroianni, Daniela Casati, Valentina Signorelli, Eleonora Rosti, Vera Cecotti, Matteo Ceccarello, Enrico Ferrazzi
INTRODUCTION: Current classification of hypertensive disorders of pregnancy (HDP) is mostly based on temporal classification differentiating HDP according to early and late onset of the disease. However, epidemiological and clinical data suggest that there are two different clinical phenotypes of HDP that coexist at any gestational age: HDP associated to intrauterine growth restriction (HDP-IUGR) and HDP associated to appropriate for gestational age fetal growth (HDP-AGAf). The aim of the study was to evaluate the association of first trimester uterine arteries (UtA) by Doppler velocimetry, and maternal risk factors with HDP according to two different classifications: one based on gestational age at delivery (early- and late-HDP), and one based on longitudinal ultrasound evaluation of fetal growth (HDP-IUGR and HDP-AGAf), independently of the gestational age...
November 20, 2017: Journal of Maternal-fetal & Neonatal Medicine
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"