نتایج جستجو برای: spectral doppler

تعداد نتایج: 208190  

2017
Qingjun Zhang Feng Xiao Zegang Ding Meng Ke Tao Zeng

Synthetic aperture radar (SAR) sliding spotlight work mode can achieve high resolutions and wide swath (HRWS) simultaneously by steering the radar antenna beam. This paper aims to obtain well focused images using sliding spotlight mode with the Chinese Gaofen-3 SAR sensor. We proposed an integrated imaging scheme with sliding spotlight echoes. In the imaging scheme, the two-step approach is app...

2001
E. Mason W. Skidmore

We present high resolution time-resolved optical spectra of the high inclination short orbital period dwarf nova V893 Sco. We performed spectral analysis through radial velocity measurements, Doppler mapping, and ratioed Doppler maps. Our results indicate that V893 Sco's accretion disk is dissimilar to WZ Sge's accretion disk, and does not fit any of the current accretion disk models. We derive...

Journal: :Optics express 2013
Danuta M Bukowska Ladislav Derzsi Szymon Tamborski Maciej Szkulmowski Piotr Garstecki Maciej Wojtkowski

Although Doppler optical coherence tomography techniques have enabled the imaging of blood flow in mid-sized vessels in biological tissues, the generation of velocity maps of capillary networks remains a challenge. To better understand the origin and information content of the Doppler signal from small vessels and limitations of such measurements, we used joint spectral and time domain optical ...

Journal: :Circulation 1980
N H Silverman T A Ports A R Snider N B Schiller E Carlsson D C Heilbron

velocity probe. Circulation 40: 603, 1969 15. Greenfield JC, Harley A, Thompson HK, Wallace AG: Pressure-flow studies in man during atrial fibrillation. J Clin Invest 47: 2411, 1968 16. Goldberg BB: Suprasternal ultrasonography. JAMA 215: 245, 1971 17. Bommer WJ, Miller LR, Mason DT, DeMaria AN: Enhancement of pulsed Doppler echocardiography in the evaluation of aortic valve disease by the deve...

Journal: :Radiology 2003
Edward G Grant Carol B Benson Gregory L Moneta Andrei V Alexandrov J Dennis Baker Edward I Bluth Barbara A Carroll Michael Eliasziw John Gocke Barbara S Hertzberg Sandra Katanick Laurence Needleman John Pellerito Joseph F Polak Kenneth S Rholl Douglas L Wooster R Eugene Zierler

The Society of Radiologists in Ultrasound convened a multidisciplinary panel of experts in the field of vascular ultrasonography (US) to come to a consensus regarding Doppler US for assistance in the diagnosis of carotid artery stenosis. The panel's consensus statement is believed to represent a reasonable position on the basis of analysis of available literature and panelists' experience. Key ...

1998
Kent Stråhlén

Velocity spectra of a flow can be made by ultrasound Doppler measurements. Using only part of the information in these spectra, it is possible to reconstruct the solenoid part and the support of the flow. Here we demonstrate that using a local minimisation combinatorical algorithm and a certain neighbourhood structure it is possible to reconstruct all of the flow, hence also the divergence. In ...

Journal: :Anesthesia and analgesia 2005
Rebecca A Schroeder Jonathan B Mark

Transesophageal echocardiography is a crucial tool in intraoperative evaluation of newly implanted/repaired heart valves because suspected valvular malfunction needs to be identified and sometimes surgically corrected. Although color Doppler is often adequate in evaluating the expected regurgitant jets, as well as excluding pathologic paravalvular leaks, spectral Doppler techniques are the most...

Journal: :Circulation 1985
P J Currie J B Seward G S Reeder R E Vlietstra D R Bresnahan J F Bresnahan H C Smith D J Hagler A J Tajik

Studies of the correlation of aortic valve gradient determined by continuous-wave Doppler echocardiography and that determined at catheterization have, to date, involved young patients and nonsimultaneous measurements. We therefore obtained simultaneous Doppler echocardiographic and catheter measurements of pressure gradient in 100 consecutive adults (mean age 69, range 50 to 89 years). In 63 p...

2005
R. - J. Lu Y. - P. Qin Z. - B. Zhang T. - F. Yi

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