Search results for "Duplex"
showing 10 items of 83 documents
The numerical simulation of heat transfer during a hybrid laser–MIG welding using equivalent heat source approach
2014
International audience; The present study is dedicated to the numerical simulation of an industrial case of hybrid laser-MIG welding of high thickness duplex steel UR2507Cu with Y-shaped chamfer geometry. It consists in simulation of heat transfer phenomena using heat equivalent source approach and implementing in finite element software COMSOL Multiphysics. A numerical exploratory designs method is used to identify the heat sources parameters in order to obtain a minimal required difference between the numerical results and the experiment which are the shape of the welded zone and the temperature evolution in different locations. The obtained results were found in good correspondence with …
Polycystic ovarian syndrome: assessment with color Doppler angiography and three-dimensional ultrasonography.
1999
We conducted a three-dimensional ultrasonographic evaluation of the size and structure of the ovaries of women who had clinical and biochemical findings suggestive of polycystic ovary syndrome. We carried out a comparative color Doppler frequency and color Doppler amplitude study of the vascular patterns of these ovaries. This study involved 65 women of reproductive age with polycystic ovary syndrome and 25 eumenorrheic women who were not taking hormonal contraceptives and who had a body mass index below 25 kg/m2. Compared to controls, women with polycystic ovary syndrome had larger ovaries and thicker stroma, increased impedance in the uterine arteries, increased stromal vascularity with d…
Volume flow in the common carotid artery does not decrease postprandially.
2003
Background and Purpose. A commonplace explanation for postprandial fatigue is the assumption of the redistribution of perfusion from the cerebral to the mesenterial territory. However, this assumption has never been scientifically proven. Methods. Because approximately 70% of the blood flow in the common carotid artery (CCA) is directed to the internal carotid artery, this vessel can be seen as a major brain-supplying artery. Flow volume in the CCA can be measured by color M-mode duplex sonography. The authors investigated the flow volume rate in 20 healthy volunteers before and after the intake of a high-energy meal. Heart rate, blood pressure, and expiratory CO2 were also measured at both…
Transcranial Doppler ultrasound study of the effects of nitrous oxide on cerebral autoregulation during neurosurgical anesthesia: a randomized contro…
2003
Object. Nitrous oxide has an adverse effect on cerebrovascular hemodynamics. Increased intracranial pressure, cerebral blood flow (CBF), cerebral metabolic rate of O2 (CMRO2), and reduced autoregulation indices have been reported, but their magnitudes are still being debated. This study was designed to evaluate the effect of N2O on CBF and autoregulatory indexes during N2O—sevoflurane anesthesia in a prospective randomized controlled series of patients. Methods. Two groups of 20 patients were studied on the basis of the use of N2O in the anesthetic gas mixture. The transient hyperemic response test, which relies on transcranial Doppler ultrasound techniques, was used to assess cerebral hemo…
Color-coded duplex ultrasonography of the origin of the vertebral artery: normal values of flow velocities.
2000
The introduction of color-coded duplex ultrasonography has improved the ease of performing ultrasound investigations of the vertebral arteries. So far, normal values of flow velocities have been reported only for the intertransverse region of the vertebral artery (V2 segments). Atherosclerotic disease at the origin of the vertebral arteries (V0 segment) is frequent and is one of the risk factors for vertebrobasilar ischemic disease. Normal values of flow velocities of the vertebral artery origin are needed to assess pathologic findings, such as vertebral artery origin stenosis or dissection. The aim of this study was to describe the normal flow velocities of vertebral artery origin (V0 segm…
Evaluation of regional haemodynamics and alterations of vascular wall of the lower limbs in hypertensive subjects
1995
This study was designed to analyse the relationship between arterial hypertension and changes in arterial blood flow and vascular wall damage of the lower limbs in hypertensive patients with various degrees of hypertension. Six hundred and fifty-four hypertensive patients (421 males and 233 females) aged 35 to 70 years and 88 healthy subjects (63 males and 25 females) aged 39 to 60 years were studied. Strain-gauge plethysmography of the lower limbs was used to calculate arterial calf blood flow (RF), arterial calf blood flow after post-ischaemic hyperaemia (PF), basal and minimal vascular resistances (BVR and MVR), time to reach peak flow (tPF), time until 50% reduction of peak flow (tT1/2)…
Infrequent early recanalization of greater saphenous vein after endovenous laser treatment
2003
Abstract Objective The frequency of recanalization of the greater saphenous vein (GSV) after endovenous laser treatment (ELT) is unclear. This study was undertaken to establish the incidence of early recanalization after ELT and to study the histopathologic features of reperfused and excised GSV. Methods One hundred nine GSV in 85 consecutive patients with clinical stage C 2-6 E P,S A S,P,D P R disease were treated with ELT. Twelve months of follow-up with duplex scanning at regular intervals was possible in 104 treated veins (95.4%) in 82 patients (96.5%). Recanalized vessels were removed surgically and examined at histopathology. Results ELT-induced occlusion proved permanent at duplex sc…
Incidence and severity of postthrombotic syndrome after iliofemoral thrombosis - results of the Iliaca-PTS - Registry.
2021
Summary: Background: Deep venous thrombosis (DVT) and in particular, iliofemoral thrombosis (IFT) can lead to recurrent thrombosis and postthrombotic syndrome (PTS). Data on the prevalence, predictors and outcome of IFT are scarce. Patients and methods: We retrospectively searched our database of outpatients who had presented with DVT and IFT including the iliac veins from 2014 until 2017. In addition, we performed a prospective registry in a subgroup of patients with IFT. These patients received duplex ultrasound, magnetic resonance venography and measurement of symptom-free walking distance using a standardized treadmill ergometry. The severity of PTS was analyzed using the Villalta-Scal…
Superficial venous thrombosis: Prevalence of common genetic risk factors and their role on spreading to deep veins
2008
Introduction. Superficial venous thrombosis (SVT) has been considered for a long time a limited clinical condition with a low importance, but this approach has changed in recent years, when several studies demonstrated spreading to deep veins occurring from 7.3 to 44%, with high prevalence of pulmonary embolism . Materials and Methods. To evaluate the prevalence of genetic risk factors for VTE in patients suffering from SVT on both normal and varicose vein, and to evaluate their role on spreading to deep veins, we studied 107 consecutive outpatients with symptomatic SVT. Ultrasound examination was performed, and the presence of FV Leiden, Prothrombin G20210A mutation, MTHFR C677T mutation w…
Symptomatic Deep Femoral Artery Pseudoaneurysm Endovascular Exclusion. Case Report and Literature Review.
2017
Deep femoral artery pseudoaneurysms (DFAPs) are rare and generally occur after penetrating trauma or surgical procedures. A 36-year-old obese man presented with pain in correspondence of the anterior-lateral thigh after 6 months from gunshot wound. Duplex and computed tomography (CT) showed a bilobed right DFAP (maximal diameter 12.9 cm). The patient was managed urgently, under local anesthesia, by placement in the distal DFA of a Viabahn 8 Ã 100-mm stent graft (W L Gore & Associates, Inc). The postoperative course was uneventful, and the 24-month CT showed regular stent-graft patency and 20-mm DFAP shrinkage. The literature review reported 8 cases of DFAPs; of these 6 were managed by endo…