Search results for "doppler"
showing 10 items of 637 documents
Second trimester uterine arteries pulsatility index is a function of placental pathology and provides insights on stillbirth aetiology: A multicenter…
2022
Introduction: The aim of this study was to investigate the relationships between maternal vascular malperfusions (MVM) and second trimester uterine arteries pulsatility index (UtA-PI) in cases of stillbirth (SB), compared to live-birth (LB) matched controls. Methods: This was a multicentre, observational, matched case-control study performed at five referral maternity centres over a 4-year period including SB and LB control pregnancies at high-risk for preeclampsia (PE) and/or fetal growth restriction (FGR), matched and stratified for UtA-PI MoM quartiles values of the SB cases. Logistic regression was used to assess the rates of each MVM finding, within each increasing MoM quartile subcate…
Colour Doppler-guided haemorrhoidal artery ligation: an adjunct in identification of haemorrhoidal vessels.
2012
Not available (case report)
Kinetic power of quasars and statistical excess of MOJAVE superluminal motions
2012
The MOJAVE survey contains 101 quasars with a total of 354 observed radio components that are different from the radio cores, among which 95% move with apparent projected superluminal velocities with respect to the core, and 45% have projected velocities larger than 10c (with a maximum velocity 60c). Doppler boosting effects are analyzed to determine the statistics of the superluminal motions. We integrate over all possible values of the Lorentz factor the values of the kinetic energy corresponding to each component. The calculation of the mass in the ejection is carried out by assuming the minimum energy state. This kinetic energy is multiplied by the frequency at which the portions of the…
Determination of defect content and defect profile in semiconductor heterostructures
2011
In this article we present an overview of the technique to obtain the defects depth profile and width of a deposited layer and multilayer based on positron annihilation spectroscopy. In particular we apply the method to ZnO and ZnO/ZnCdO layers deposited on sapphire substrates. After introducing some terminology we first calculate the trend that the W/S parameters of the Doppler broadening measurements must follow, both in a qualitative and quantitative way. From this point we extend the results to calculate the width and defect profiles in deposited layer samples.
Laser Doppler flowmetry in subepidermal tumours and in normal skin of rats during localized ultrasound hyperthermia.
1988
Laser Doppler flowmetry has been applied to normal skin and to subepidermal tumours during localized ultrasound hyperthermia in the rat. In normal skin, 40 degrees C hyperthermia only induced a marginal increase in the red blood cell flux. Significant increases occurred after 20 min at 42 degrees C and after 4 min at 44 degrees C. During 44 degrees C hyperthermia maximum fluxes were reached after 24 min. Thereafter, the flow declined and finally approached preheating values. In contrast, in subepidermal tumours 40 degrees C hyperthermia on the average induced a slight decrease of the flux. During 42 degrees C hyperthermia a significant flow decrease was found after 40 min of heating. Follow…
Microcirculatory Function, Tissue Oxygenation, Microregional Redox Status and ATP Distribution in Tumors Upon Localized Infrared-A-Hyperthermia at 42…
2003
Since local hyperthermia (HT) affects microenvironmental parameters, the aim of the study was to analyze the impact of 42°C-HT on microcirculatory function, tumor pO2, microregional redox status and ATP distribution in experimental rat tumors. Subcutaneously growing DS-sarcomas were treated with localized HT using infrared-A radiation resulting in a mean tumor temperature of 42°C. The relative red blood cell (RBC) flux in the tumor was assessed using the laser Doppler technique and the mean tumor pO2 measured continuously using O2-sensitive catheter electrodes. In a second series of experiments, the microregional distribution of the mitochondrial redox status and ATP concentration was measu…
Monitoring of fracture calluses with color Doppler sonography.
1999
Purpose Fracture callus formation is closely associated with vascular invasion, and the use of color Doppler sonography has been suggested as a means to monitor, earlier than gray-scale sonography, the first stages of the healing process. We report the findings in a series of patients with tibial fractures in whom both gray-scale sonography and color Doppler imaging were employed to monitor new bone formation at the fracture site. Methods Twenty patients with tibial fractures treated with external fixator frames were examined sonographically about 10 days after surgery and then about every 25 days until radiographic demonstration of consolidation. Results Eighteen of 20 patients had a well-…
The predictive role of pelvic magnetic resonance in the follow up of spontaneous or induced puberty in turner syndrome
2018
Abstract Puberty is a critical age for patients with Turner syndrome (TS): infertility is reported to be linked to karyotype and spontaneous puberty and menarche occur in approximately 30% of patients, especially in mosaicism. However, it is not always predictable considering hormonal pattern and pelvic transabdominal ultrasound scan (US). The aim of the study is to compare the accuracy of Magnetic Resonance Imaging (MRI) and US to evaluate uterine and gonads volume, to visualize the presence of follicles and to predict spontaneous puberty and menarche in girls with TS. In a retrospective study, we evaluated 19 TS patients (age: 9–16 years), who underwent transabdominal pelvic US and pelvic…
Utilidad de la ecografía Doppler infrapoplítea en pacientes con sospecha de enfermedad tromboembólica venosa
2017
La enfermedad tromboembólica venosa (ETEV) es una enfermedad vascular compleja con una patogénesis multifactorial. Su importancia radica en su alta prevalencia y en la morbimortalidad asociada. Agrupa dos presentaciones clínicas mayores, la más frecuente es la trombosis venosa profunda (TVP) y la más temida por su riesgo de mortalidad es el tromboembolismo pulmonar (TEP). Se identifican principalmente dos localizaciones de TVP en los miembros inferiores (MMII): la trombosis proximal (TP) cuando afecta a las venas profundas del hueco poplíteo y proximales a éste, y la trombosis distal cuando afecta a las venas profundas y musculares de la pantorrilla. La trombosis distal puede darse de forma…
Image guidance to improve reliability and data integrity of transcranial Doppler sonography.
2012
Abstract Background Principles and accuracy of image-guided transcranial Doppler (IG TCD) sonography have been published recently. However, it remains open whether combination of image guidance and TCD offers an additional clinical advantage. This study scores the accuracy of conventional TCD examinations and investigates the potential improvement of TCD data integrity and reliability regarding the additional use of IG. Methods Conventional TCD was performed by a group of experienced investigators, who were blinded to images of a navigation system tracking the Doppler probe, whereas an independent observer documented the TCD findings, acquired by the investigators, due to saving spatial dat…