[Changes in the ultrasound power spectrum due to concentric stenoses of the femoral artery of the dog].

Vasa Suppl

Klinische Forschung, Hoechst AG, Werk Kalle-Albert, Wiesbaden, BRD.

Published: March 1992

An artificial stenosis model consisting of a revolving centric cylinder with six boreholes (10-60% diameter reduction) was implanted in the superficial femoral artery of anaesthezised beagles (n = 10). Range gated pulsed Doppler signals were recorded at 7 sites between three diameters upstream to ten diameters downstream the Angle corrected parameters derived from the contour of spectral lines between 3 and 21dB on both sides of mode frequency were calculated for different time windows. Two groups of dogs could be distinguished. Group A showed marked downstream power spectrum changes which did not correlate to the degree of stenosis. In Group B, in contrast, the degree of power spectral disturbances correlated to the degree of stenosis. It was suggested that partial thrombosis of the stenoses during measurement provides an acceptable explanation for the missing correlation in Group A.

Download full-text PDF

Source

Publication Analysis

Top Keywords

power spectrum
8
femoral artery
8
degree stenosis
8
[changes ultrasound
4
ultrasound power
4
spectrum concentric
4
concentric stenoses
4
stenoses femoral
4
artery dog]
4
dog] artificial
4

Similar Publications

Variable power functional dilution adjustment of spot urine.

Sci Rep

January 2025

Praxis Dr.Carmine, Etzelstrasse 21, Pfaeffikon SZ, 8808, Switzerland.

Spot-urinary biomarkers are crucial in medical, epidemiological, and environmental studies, but their variability due to hydration levels requires precise dilution adjustments. Traditional methods, like conventional creatinine correction (CCRC), are limited in compensating for variations in urine concentration, causing substantial inconsistencies, particularly at the extremes of the diuresis spectrum. While restricting the creatinine (CRN) range to 0.

View Article and Find Full Text PDF

Statistical-based detection of pilot contamination attack for NOMA in 5G networks.

Sci Rep

January 2025

Department of Information Technology, Faculty of Computers and Information, Assiut University, Assiut, Assiut, 71515, Egypt.

Fifth-generation (5G) communication technologies, such as millimeter wave communication, massive multiple-input-multiple-output and non-orthogonal-multiple-access (NOMA) are playing a pivotal role in promoting the modern applications of the Internet-of-Things. Using non-orthogonal resource allocation, NOMA can increase spectrum efficiency and achieve wide connectivity with low transmission delay and signaling cost. Despite the high potential of NOMA in 5G communications, NOMA is susceptible to a pilot contamination attack (PCA), in which an attacker resents the same pilot signals as authorized users.

View Article and Find Full Text PDF

Spherical harmonics texture extraction for versatile analysis of biological objects.

PLoS Comput Biol

January 2025

European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Heidelberg, Germany.

The characterization of phenotypes in cells or organisms from microscopy data largely depends on differences in the spatial distribution of image intensity. Multiple methods exist for quantifying the intensity distribution - or image texture - across objects in natural images. However, many of these texture extraction methods do not directly adapt to 3D microscopy data.

View Article and Find Full Text PDF

Purpose: The purpose of this work was to evaluate the image quality of a commercial CT scanner equipped with a novel detector and filtration technology called PureVision Optics (PVO).

Methods: CT number, noise, contrast-to-noise ratio (CNR), modulation transfer function (MTF), and noise power spectrum (NPS) were assessed using the ACR CT Accreditation phantom scanned with various acquisitions at 80 kV, 100 kV, 120 kV, and 135 kV, each with multiple CTDIvol values of 20 mGy, 40 mGy, and 65 mGy. Artifacts were evaluated in an anthropomorphic head phantom, a cadaver head, and in patient studies.

View Article and Find Full Text PDF

To facilitate the development of compact multi-wavelengths lasers, we reported the experimental demonstration of dual seed sources master oscillator power amplifier (MOPA) QCLs. The devices were based on a sandwich configuration consisting of dual seed sources and a central power amplifier. Emission spectrum of devices was modulated by switching seed sources.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!