Search results for "DOPPLER"
showing 10 items of 637 documents
A non-stationary relay-based 3D MIMO channel model with time-variant path gains for human activity recognition in indoor environments
2021
AbstractExtensive research showed that the physiological response of human tissue to exposure to low-frequency electromagnetic fields is the induction of an electric current in the body segments. As a result, each segment of the human body behaves as a relay, which retransmits the radio-frequency (RF) signal. To investigate the impact of this phenomenon on the Doppler characteristics of the received RF signal, we introduce a new three-dimensional (3D) non-stationary channel model to describe the propagation phenomenon taking place in an indoor environment. Here, the indoor space is equipped with a multiple-input multiple-output (MIMO) system. A single person is moving in the indoor space an…
The predictive power of transcranial sonography in movement disorders: a longitudinal cohort study.
2018
Transcranial sonography (TCS) is a noninvasive, easily performed, and commonly available neuroimaging technique useful for the study of brain parenchyma in movement disorders. This tool has been increasingly used in the diagnosis of Parkinson’s disease and atypical parkinsonism. The aim of the study was to evaluate the applicability of this technique as supportive tool in the early diagnosis of movement disorders. We performed TCS on 315 individuals which were diagnosed as healthy controls or affected by idiopathic Parkinson’s disease, monogenetic subtypes of Parkinson’s disease, atypical parkinsonism, and Dementia with Lewy bodies. Five TCS diagnostic patterns were defined on the basis of …
Two-dimensional and three-dimensional sonography of conjoined twins.
2002
Purpose The aim of this study was to evaluate and compare the diagnostic capabilities of 2-dimensional (2D) and 3-dimensional (3D) sonography for the study of conjoined twins. Methods Four pregnant women with an initial 2D sonographic diagnosis of conjoined twins were examined with color Doppler sonography, 3D multiplanar sonography, and orthogonal plane imaging and 3D surface rendering. Results All 4 cases of conjoined twins were initially diagnosed with either transvaginal or transabdominal 2D sonography. 3D sonography afforded more realistic views and demonstrated more clearly the linking areas and surface anomalies, but 2D and color Doppler sonography provided more definitive and specif…
Median arcuate ligament syndrome, a rare case of chronic abdominal pain
2018
The median arcuate ligament syndrome (MALS) is a rare disease characterized by abdominal pain caused by the external compression of the celiac artery by the median arcuate ligament. Surgical treatment is indicated, but given the non-specific symptoms, these patients are often hospitalized in the Departments of Internal Medicine where the diagnosis may be unknown. We present a case of MALS admitted to our Internal Medicine Division. An abdominal ultrasound in a woman with longstanding abdominal pain showed elevated celiac artery velocities during forced expiration. Computed tomography angiography (CTA) of the abdomen showed stenosis of the origin of the celiac artery and confirmed the diagno…
Accuracy of doppler echocardiography in measuring right-heart pressure in patients with pulmonary hypertension
2010
The assessment of pulmonary pressure is of great clinical importance not only for diagnostic purposes, but also for prognosis in patients with pulmonary arterial hypertension. The present study was undertaken on a consecutive basis with a group of patients who had had a previous diagnosis of pulmonary hypertension based on echocardiography, and were referred to our institute. The aim of this study was to determine how accurate Doppler echocardiography is in measuring right-heart pressures.
Glycoprotein and ganglioside changes in human trophoblasts after exposure to pulsed doppler ultrasound
1995
Changes in glycoprotein and ganglioside composition in human trophoblasts (eighth week of gestation) after in vitro exposure to pulsed Doppler ultrasound (pulse duration 1.22 microseconds; repetition frequency 11.1 kHz; center frequency 4 MHz; ISPPA = 175.5 W/cm2; ISPTA = 0.59 W/cm2) were investigated. Evacuated trophoblasts were divided in two halves and insonated for 10 min on top of a 6-cm layer of 5% gelatin in 50-mL tubes (Falcon) at 37 degrees C. One half of each trophoblast was sham insonated and served as an internal control. After insonation trophoblasts were maintained at 37 degrees C for 24 h. Glycoproteins were detected using alpha-D-mannose specific lectins from Galanthus nival…
Coupling hydrodynamics and radiation calculations for star-jet interactions in active galactic nuclei
2016
Context. Stars and their winds can contribute to the non-thermal emission in extragalactic jets. Because of the complexity of jet-star interactions, the properties of the resulting emission are closely linked to those of the emitting flows. Aims. We simulate the interaction between a stellar wind and a relativistic extragalactic jet and use the hydrodynamic results to compute the non-thermal emission under different conditions. Methods. We performed relativistic axisymmetric hydrodynamical simulations of a relativistic jet interacting with a supersonic, non-relativistic stellar wind. We computed the corresponding streamlines out of the simulation results and calculated the injection, evolut…
Clinical-anamnestic and instrumental data in outpatients suffering from venous disease
1995
The authors studied 200 consecutive outpatients with symptoms due to venous disease of the lower limbs. All the patients underwent anamnestic, clinical and instrumental evaluation (c.w. Doppler velocimetry and strain-gauge plethysmography). The results of this study showed that some anamnestic and clinical data are significantly related to venous disease detected by instrumental techniques. The superficial and deep vein hypertension were, instead, correlated to oral contraceptive use.
Microvascular skin blood flow following the ingestion of 75 g glucose in healthy individuals.
2009
It is expected that microvascular blood flow might be affected by blood glucose, blood insulin and C-peptide levels. In our investigation skin microvascular blood flow (LDF) was measured using laser doppler fluxometry at skin temperatures of 37 degrees C and 44 degrees C during a 75 g oral glucose load (OGT) or water in ten healthy volunteers (6 male, 4 female, age: 28.1+/-4.0) who had fasted overnight. The transcutaneous oxygen tension (tcPO2) was measured using a transcutaneous oxygen electrode at a temperature of 44 degrees C. The microvascular response to acetylcholine was investigated before the start of the ingestion period and after 30 minutes. In addition, the capillary blood cell v…
Ultrasonographic Detection of Vascularity of Focal Breast Lesions: Microvascular Imaging Versus Conventional Color and Power Doppler Imaging.
2021
To compare microvascular flow imaging (MVFI) to conventional Color-Doppler (CDI) and Power-Doppler (PDI) imaging in the detection of vascularity of Focal Breast Lesions (FBLs). A total of 180 solid FBLs (size: 3.5–45.2 mm) detected in 180 women (age: 21–87 years) were evaluated by means of CDI, PDI, and MVFI. Two blinded reviewers categorized lesion vascularity in absent or present, and vascularity pattern as (a) internal; (b) vessels in rim; (c) combined. The presence of a “penetrating vessel” was assessed separately. Differences in vascularization patterns (chi2 test) and intra- and inter-observer agreement (Fleiss method) were calculated. ROC analysis was performed to assess performance…