Doppler velocimetry

INTRODUCTION AND IMPORTANCE: The diagnostic criteria for Quintero staging in twin-to-twin transfusion syndrome (TTTS) are not applicable in all cases of TTTS, such as those in which the symptoms overlap with other monochorionic twin complications such as selective intrauterine growth restriction (sIUGR). CASE PRESENTATION: A 25-year-old woman, G1P0A0, at 22-24 weeks' gestational age was diagnosed with TTTS, with no outstanding history of medication use during pregnancy, and no family history of genetic disorder or twin pregnancy...

Fetal growth restriction associated with hypertensive disorders of pregnancy (FGR-HDP) is a prevalent pathology with a higher risk of perinatal morbimortality. In this condition, placental insufficiency and endothelial dysfunction serve key roles. The present prospective cohort study monitored 11 patients with an FGR-HDP and 15 with full-term normotensive pregnancies and studied post-natal intracellular calcium concentration ([Ca2+ ]i ) signals in human umbilical vein endothelial cells (HUVECs). Small fetuses with placental insufficiency were identified using fetal biometry with Doppler velocimetry...

PURPOSE: Ductus venosus (DV) Doppler velocimetry reflects fetal cardiac function. Gestational diabetes mellitus (GDM) is assumed to impair cardiac function due to fetal hyperglycemia. The purpose of this study was to assess the ability of DV Doppler to predict an adverse perinatal outcome (APO) in term pregnancies with GDM. METHODS: This is a retrospective cohort study including GDM pregnancies of singleton, non-anomalous fetuses without any signs of placental dysfunction...

OBJECTIVE: To evaluate the maternal-fetal hemodynamic effects after osteopathic manipulative treatment by measuring vital signs and Doppler velocimetry in third-trimester pregnant women. MATERIALS AND METHODS: This is a prospective study with pregnant women undergoing outpatient follow-up and hospitalized in a ward at Instituto Fernandes Figueira/Fiocruz, between August 2021 to August 2022, during the SARS-CoV-2 pandemic. This study was registered in REBEC under Register Number RBR-9q7kvg and approved by the ethics committee under number 32216620...

OBJECTIVE: To assess the association of the umbilicocerebral ratio (UCR) with adverse perinatal outcome in late preterm small-for-gestational age (SGA) fetuses and to investigate the effect on perinatal outcomes of immediate delivery. DESIGN: Multicentre cohort study with nested randomised controlled trial (RCT). SETTING: Nineteen secondary and tertiary care centres. POPULATION: Singleton SGA pregnancies (estimated fetal weight [EFW] or fetal abdominal circumference [FAC] <10th centile) from 32 to 36+6  weeks...

INTRODUCTION: Growth-restricted fetuses may have changes in their neuroanatomical structures that can be detected in prenatal imaging. We aim to compare corpus callosal length (CCL) and cerebellar vermian height (CVH) measurements between fetal growth restriction (FGR) and control fetuses and to correlate them with cerebral Doppler velocimetry in growth restricted fetuses. METHODS: This was a prospective cohort of FGR after 20 weeks of gestation with ultrasound measurements of CCL and CVH...

In the process of multi-pulse laser ablation, inter-pulse delay time, Δt, is known to be an important parameter for maximizing ablation efficiency as well as impulse imparted to the target. In this work, using photon Doppler velocimetry, we show that for single pairs of colinear pulses (1064 nm, 8 ns, ∼ 60 J cm-2 per pulse) in air, the peak free surface velocity of the back surface of an aluminum target (125 µm thick) is increased, by a factor of nearly 3, when Δt = 10 microseconds, compared with both pulses arriving simultaneously (Δt = 0)...

BACKGROUND: The "great obstetrical syndromes" of fetal growth restriction and hypertensive disorders of pregnancy can occur individually or be interrelated. Placental pathologic findings often overlap between these conditions, regardless of whether one or both diagnoses are present. Quantification of placental villous structures in each of these settings may identify distinct differences in developmental pathways. OBJECTIVE: To determine how quantity and surface area of placental villi and vessels differ between severe, early-onset fetal growth restriction with absent/reversed umbilical artery Doppler indices, hypertensive disorders of pregnancy, and the two conditions combined among subjects with disease severity warranting early preterm delivery...

Objective Doppler velocimetry provides a sensitive, non-invasive, and safe method of surveillance of fetal hemodynamics and fetomaternal circulation. Cerebroplacental ratio (CPR) is an indicator of placental function and fetal maladaptation to placental insufficiency. Cerebroplacental ratio (CPR) is becoming a significant indicator of unfavorable pregnancy outcomes, which has implications for the assessment of fetal well-being. This study aimed to determine the cut-off value of the cerebroplacental ratio (CPR) in appropriate for gestational age (AGA) fetuses in high-risk mothers to predict adverse perinatal outcomes...

Theoretical analysis of Richtmyer-Meshkov instability (RMI) experiments for solid strength shows that the strain rate for a given shock should be inversely proportional to the length scale of the sine wave perturbations when η_{0}k, the nondimensional amplitude to wavelength ratio, is held fixed. To isolate the effect of strain rate on strength, free-surface RMI specimens of annealed copper were prepared with three perturbation regions with the same η_{0}k but different length scales, characterized by the wavelength λ varying by a factor of 4...

Cystic endometrial hyperplasia (CEH)-pyometra complex is the most common uterine infection in adult and elderly bitches and can cause renal dysfunction. The aim of this study was to measure and compare urinary creatinine, urea, symmetric dimethylarginine (SDMA), urinary protein-creatinine ratio (UPC), measurement of systolic blood pressure (SBP), and Doppler velocimetry of renal arteries in patients with CEH-pyometra complex before and after an average of 6 months of treatment, evaluating the possibility of the changes persisting...

Laser-driven flyers (LDF), which can launch the flyer on the interaction of a laser pulse with a thin film of metal, have been widely used in many fields, such as ignition, space scrap metal science, and dynamic high-pressure physics. However, at present, further development of LDF is being hindered by the high reflectivity of the ablation layer and low energy utilization efficiency of LDF on the fiber end face. Herein, improved LDFs were designed and fabricated by mask plate and magnetron sputtering. Improved LDF incorporates a Ti/Al composite film as the ablation layer, while the flyer layer features a smaller diameter round platform design...

Fetal heart rate monitoring during general anesthesia for non-obstetric surgery at viable gestational ages is recommended to evaluate fetal well-being during the intervention. Alteration induced by anesthetic drugs could mimic fetal acute hypoxia, leading to pointless Cesarean sections. We report a case of a pregnant woman in the third trimester undergoing neurosurgical surgery. The continuous heart rate registration showed a non-reassuring pattern, potentially inducing the multidisciplinary team to expedite the delivery...

OBJECTIVE: Laparotomy-assisted fetoscopic closure of spina bifida utilizing heated-humidified carbon dioxide gas has been associated with less maternal morbidity than open in-utero spina bifida closure. Fetal cardiovascular changes during these surgical interventions are not well defined. Our objective was to compare fetal bradycardia (defined as fetal heart rate (FHR)<110 bpm over 10 minutes) and changes in umbilical artery Doppler parameters throughout open in-utero closure with those observed during laparotomy-assisted fetoscopic closure...

Objective Doppler velocimetry is an established method of antepartum fetal surveillance in pre-eclampsia. Cerebroplacental ratio detects the centralization of fetal blood flow and the insufficiency in placental circulation. It is postulated to be a better marker of perinatal outcome than either vessel Doppler alone. The current study aims to assess the cerebroplacental ratio as a predictor of adverse perinatal outcomes and compare it to the systolic/diastolic (S/D) ratio of umbilical artery (UA) and middle cerebral artery (MCA) in hypertensive disorders of pregnancy...

A coherent Doppler LIDAR (CDL) with long-duration frequency-modulated pulses was demonstrated and validated by analyzing the data observed by a prototype. In traditional CDL using short-duration single-frequency pulses (PCDL; pulsed CDL), there exists a trade-off relationship between distance and velocity resolution. Meanwhile, in earlier work, a theoretical framework of CDL using long-duration frequency-modulated pulses (FMCDL; frequency-modulated CDL) was put forth to eliminate the trade-off. We developed the prototype to be operated as both a PCDL and FMCDL...

IMPORTANCE: Fetal growth restriction (FGR) is a common pregnancy complication and a significant contributor of fetal and neonatal morbidity and mortality, mainly due to the lack of effective screening, prevention, and management policies. OBJECTIVE: The aim of this study was to review and compare the most recently published influential guidelines on the management of pregnancies complicated by FGR. EVIDENCE ACQUISITION: A descriptive review of guidelines from the American College of Obstetricians and Gynecologists (ACOG), the Society for Maternal-Fetal Medicine, the International Federation of Gynecology and Obstetrics, the International Society of Ultrasound in Obstetrics and Gynecology, the Royal College of Obstetricians and Gynecologists, the Society of Obstetricians and Gynecologists of Canada (SOGC), the Perinatal Society of Australia and New Zealand, the Royal College of Physicians of Ireland, the French College of Gynecologists and Obstetricians (FCGO), and the German Society of Gynecology and Obstetrics on FGR was carried out...

PURPOSE: To measure non-invasively retinal venous blood flow (RBF) in healthy subjects and patients with retinal venous occlusion (RVO). METHODS: The prototype named AO-LDV (Adaptive Optics Laser Doppler Velocimeter), which combines a new absolute laser Doppler velocimeter with an adaptive optics fundus camera (rtx1, Imagine Eyes®, Orsay, France), was studied for the measurement of absolute RBF as a function of retinal vessel diameters and simultaneous measurement of red blood cell velocity...

INTRODUCTION: An optimal placement of bone conduction implants can provide more efficient mechanical transmission to the cochlea if placed in regions with greater bone column density. The aim of this study was to test this hypothesis and to determine the clinical potential of preoperative bone column density assessment for optimal implant placement. METHODS: Five complete cadaver heads were scanned with quantitative computed tomography imaging to create topographic maps of bone density based on the column density index (CODI)...

The accurate measurement of an object's motion requires knowledge of both its position and its velocity. The commonly used photonic Doppler velocimetry and broadband laser ranging techniques are ideal for conducting simultaneous dynamic experiments. Instead of employing two distinct measurement systems, we developed a hybrid system that can simultaneously measure velocity and distance in dynamic experiments. This reduces cost and complexity, particularly for multi-channel tests, by using only one probe, photodetector, and oscilloscope channel...