نتایج جستجو برای: power doppler

تعداد نتایج: 529716  

Journal: :Ultrasound in Obstetrics and Gynecology 1998

Journal: :Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine 2010
Kristina M Huster Kimberly Haas Jean Schoenborn Dominique McVean Anthony O Odibo

OBJECTIVE The purpose of this study was to evaluate the reproducibility of 3-dimensional (3D) power Doppler assessment of placental volumes and vascularization before adopting these in routine evaluation of normal and complicated pregnancies. METHODS A prospective study was performed on 30 normal singleton pregnancies from 11 to 14 weeks. To evaluate placental vascularization, 3D power Dopple...

2008
Ingemar Fredriksson Marcus Larsson Tomas Strömberg

A method to separate a Doppler power spectrum into a number of flow velocity components, measured in absolute units (mm/s), is presented. A Monte Carlo software was developed to track each individual Doppler shift, to determine the probability, p(n), for a photon to undergo n Doppler shifts. Given this shift distribution, a mathematical relationship was developed and used to calculate a Doppler...

2017
Nimmagadda Padmaja Souri Varadarajan Enugonda Ramyakrishna

An efficient algorithm based on Empirical Mode Decomposition (EMD) de-noising using soft 10 threshold techniques for accurate doppler profile detection and Signal to Noise Ratio (SNR) improvement of 11 MST Radar Signals is discussed in this paper. Hilbert Huang Transform (HHT) is a time-frequency analysis 12 technique for processing radar echoes which constitutes EMD process that decomposes the...

Journal: :Circulation 2001
F S Villanueva E W Gertz M Csikari G Pulido D Fisher J Sklenar

BACKGROUND Power Doppler is a new imaging method for detecting microbubbles during myocardial contrast echocardiography (MCE) based on the registration of variance resulting from ultrasound-induced nonlinear bubble behavior. We tested the hypothesis that power Doppler imaging can be used to quantify coronary stenoses. METHODS AND RESULTS Three left anterior descending (LAD) coronary stenoses ...

Journal: :Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology 2015
S Zeng J Zhou Q Peng L Tian G Xu Y Zhao T Wang Q Zhou

OBJECTIVES To use three-dimensional (3D) power Doppler ultrasound to investigate cerebral blood flow perfusion in fetuses with congenital heart disease (CHD). METHODS The vascularization index (VI), flow index (FI) and vascularization flow index (VFI) in the total intracranial volume and the main arterial territories (middle cerebral artery (MCA), anterior cerebral artery (ACA) and posterior ...

Journal: :Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine 2007
Chih-Yao Chen Yi-Cheng Wu Ming-Shyen Yen Jeng-Hsiu Hung Chiou-Chung Yuan Kuan-Chong Chao

OBJECTIVE The aim of this study was to compare the effectiveness of transvaginal power Doppler sonography with spectral Doppler analysis as an aid in preoperatively distinguishing primary ovarian carcinoma and metastatic carcinoma to the ovary (Krukenberg tumors). METHODS Fifty women with ovarian disease were preoperatively examined with transvaginal power Doppler sonography. Six basic parame...

Journal: :European journal of echocardiography : the journal of the Working Group on Echocardiography of the European Society of Cardiology 2002
H von Bibra D Bone U Niklasson L Eurenius A Hansen

AIMS This prospective study assesses the (1) feasibility of quantifying ultrasound myocardial perfusion studies based on the densitometric analysis of digital data and the (2) comparison of pulse inversion, second harmonic and harmonic power Doppler modalities with SPECT. METHODS AND RESULTS Twenty-three patients with suspected ischaemic heart disease had i.v. injections of Tc-Sestamibi and O...

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