Sample records for renal doppler waveform

  1. Bilateral parvus-tardus Doppler waveform in renal arteries suggests aortic coarctation: case report

    Conkbayir, I.; Yanik, B.; Keyik, B.; Edguer, T.; Hekimoglu, B. [Social Security Ankara Hospital, Dept. of Radiology, Diskapi, Ankara (Turkey)]. E-mail:


    Doppler ultrasonography (US) is an effective, inexpensive and widely used modality in renal vascular imaging. Demonstration of a parvus-tardus waveform pattern in renal arteries or intrarenal segmental arteries with Doppler US indicates a significant proximal stenosis. In the presence of a parvus-tardus pattern in both renal arteries, bilateral renal artery stenosis or a stenosis more proximal to the renal arteries should be considered.{sup 1} We present such a case and describe the Doppler ultrasonographic findings that suggested coarctation of the aorta. (author)

  2. Factors influencing the renal arterial Doppler waveform: a simulation study using an electrical circuit model (secondary publication

    Chang Kyu Sung


    Full Text Available Purpose: The goal of this study was to evaluate the effect of vascular compliance, resistance, and pulse rate on the resistive index (RI by using an electrical circuit model to simulate renal blood flow. Methods: In order to analyze the renal arterial Doppler waveform, we modeled the renal blood-flow circuit with an equivalent simple electrical circuit containing resistance, inductance, and capacitance. The relationships among the impedance, resistance, and compliance of the circuit were derived from well-known equations, including Kirchhoff’s current law for alternating current circuits. Simulated velocity-time profiles for pulsatile flow were generated using Mathematica (Wolfram Research and the influence of resistance, compliance, and pulse rate on waveforms and the RI was evaluated. Results: Resistance and compliance were found to alter the waveforms independently. The impedance of the circuit increased with increasing proximal compliance, proximal resistance, and distal resistance. The impedance decreased with increasing distal compliance. The RI of the circuit decreased with increasing proximal compliance and resistance. The RI increased with increasing distal compliance and resistance. No positive correlation between impedance and the RI was found. Pulse rate was found to be an extrinsic factor that also influenced the RI. Conclusion: This simulation study using an electrical circuit model led to a better understanding of the renal arterial Doppler waveform and the RI, which may be useful for interpreting Doppler findings in various clinical settings.

  3. Factors influencing the renal arterial Doppler waveform: a simulation study using an electrical circuit model (secondary publication)

    Sung, Chang Kyu [Dept. of Radiology, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul (Korea, Republic of); Han, Bong Soo [Dept. of Radiological Science, College of Health Science, Yonsei University, Wonju (Korea, Republic of); Kim, Seung Hyup [Dept. of Radiology, Institute of Radiation Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul (Korea, Republic of)


    The goal of this study was to evaluate the effect of vascular compliance, resistance, and pulse rate on the resistive index (RI) by using an electrical circuit model to simulate renal blood flow. In order to analyze the renal arterial Doppler waveform, we modeled the renal blood-flow circuit with an equivalent simple electrical circuit containing resistance, inductance, and capacitance. The relationships among the impedance, resistance, and compliance of the circuit were derived from well-known equations, including Kirchhoff’s current law for alternating current circuits. Simulated velocity-time profiles for pulsatile flow were generated using Mathematica (Wolfram Research) and the influence of resistance, compliance, and pulse rate on waveforms and the RI was evaluated. Resistance and compliance were found to alter the waveforms independently. The impedance of the circuit increased with increasing proximal compliance, proximal resistance, and distal resistance. The impedance decreased with increasing distal compliance. The RI of the circuit decreased with increasing proximal compliance and resistance. The RI increased with increasing distal compliance and resistance. No positive correlation between impedance and the RI was found. Pulse rate was found to be an extrinsic factor that also influenced the RI. This simulation study using an electrical circuit model led to a better understanding of the renal arterial Doppler waveform and the RI, which may be useful for interpreting Doppler findings in various clinical settings.

  4. Heartrate variation of umbilical artery Doppler waveforms.

    Hoskins, P R; Johnstone, F D; Chambers, S E; Haddad, N G; White, G; McDicken, W N


    Umbilical artery Doppler waveforms from 20 patients were used to investigate the dependence of resistance index and pulsatility index on beat to beat pulse length over short time periods for individual patients, and on the usefulness of a common normalisation formula. For individual patients the resistance index and pulsatility index were only partially correlated with pulse length. Changes in both indices occurred independently of pulse length. Use of a common normalisation formula resulted in no significant reduction of the coefficient of variation of the resistance index (p greater than 0.1), and a reduction in the coefficient of variation of the pulsatility index of 10% (p greater than 0.001). It is concluded that short term changes in resistance index and pulsatility index cannot be corrected by a common normalisation formula.

  5. Integrated Range-Doppler Map and Extended Target Classification with Adaptive Waveform for Cognitive Radar


    RANGE-DOPPLER MAP AND EXTENDED TARGET CLASSIFICATION WITH ADAPTIVE WAVEFORM FOR COGNITIVE RADAR by Jo-Yen Nieh December 2014 Dissertation...TYPE AND DATES COVERED Dissertation 4. TITLE AND SUBTITLE INTEGRATED RANGE-DOPPLER MAP AND EXTENDED TARGET CLASSIFICATION WITH ADAPTIVE WAVEFORM an extended target classification scheme while determining the target’s range-and-Doppler location with the use of adaptive waveform for a

  6. Normal Doppler velocimetry of renal vasculature in Persian cats.

    Carvalho, Cibele F; Chammas, Maria C


    Renal diseases are common in older cats. Decreased renal blood flow may be the first sign of dysfunction and can be evaluated by Doppler ultrasound. But previous studies suggest that the resistive index (RI) has a low sensitivity for detecting renal disease. Doppler waveforms of renal and intrarenal arteries demonstrate decreased blood flow before there are any changes in the RI. The purpose of this study was to evaluate the normal Doppler flowmetrics parameters of renal arteries (RAs), interlobar arteries (IAs) and abdominal aorta (AO) in adult healthy, Persian cats. Twenty-five Persian cats (13 females and 12 males with mean age of 30 months and an age range 12-60 months) with normal clinical examinations and biochemical tests and normal systemic blood pressure were given B-mode ultrasonographies in order to exclude all nephropathies, including polycystic kidney disease. All measurements were performed on both kidneys. Both kidneys (n=50) were examined by color mapping of the renal vasculature. Pulsed Doppler was used to examine both RAs, the IAs at cranial, middle and caudal sites, and the AO. The RI was calculated for all of the vessels. Early systolic acceleration (ESA) of RA and IA was obtained with Doppler spectral analysis. Furthermore, the ratio indices between RA/AO, and IA/RA velocities were calculated. The mean values of peak systolic velocity (PSV) and the diameter for AO were 53.17±13.46 cm/s and 0.38±0.08 cm, respectively. The mean RA diameter for all 50 kidneys was 0.15±0.02 cm. Considering the velocimetric values in both RAs, the mean PSV and RI that were obtained were 41.17±9.40 cm/s and 0.54±0.07. The RA had a mean ESA of 1.12±1.14 m/s(2) and the calculated upper limit of the reference value was 3.40 m/s(2). The mean renal-aortic ratio was 0.828±0.296. The IA showed PSV and RI values of 32.16±9.33 cm/s and 0.52±0.06, respectively. The mean ESA of all IAs was 0.73±0.61 m/s(2). The calculated upper limit of the reference value was 2.0m

  7. Hepatic vein Doppler waveform in patients with diffuse fatty infiltration of the liver

    Oguzkurt, Levent [Department of Radiology, Adana Teaching and Medical Research Center, Baskent University, Adana 01250 (Turkey)]. E-mail:; Yildirim, Tulin [Department of Radiology, Adana Teaching and Medical Research Center, Baskent University, Adana 01250 (Turkey); Torun, Dilek [Department of Nephrology, Adana Teaching and Medical Research Center, Baskent University, Adana (Turkey); Tercan, Fahri [Department of Radiology, Adana Teaching and Medical Research Center, Baskent University, Adana 01250 (Turkey); Kizilkilic, Osman [Department of Radiology, Adana Teaching and Medical Research Center, Baskent University, Adana 01250 (Turkey); Niron, E. Alp [Department of Radiology, Baskent University, Ankara (Turkey)


    Objective: To determine the incidence of abnormal hepatic vein Doppler waveform in patients with diffuse fatty infiltration of the liver (FIL). Materials and methods: In this prospective study, 40 patients with diffuse FIL and 50 normal healthy adults who served as control group underwent hepatic vein (HV) Doppler ultrasonography. The patients with the diagnosis of FIL were 23 men (57.5%) and 17 women aged 30-62 years (mean age {+-} S.D., 42 {+-} 12 years). Subjects in the control group were 27 men (54%) and 23 women aged 34-65 years (mean age {+-} S.D., 45 {+-} 14 years). The diagnosis of FIL was confirmed with computed tomography density measurements. The waveforms of HV were classified into three groups: regular triphasic waveform, biphasic waveform without a reverse flow, and monophasic or flat waveform. Etiological factors for FIL were diabetes mellitus (DM), hyperlipidemia and obesity (body mass index > 25). Serum lipid profile was obtained from all the patients with FIL. Results: Seventeen of the 40 patients (43%) with FIL had an abnormal HV Doppler waveform, whereas only one of the 50 (2%) healthy subjects had an abnormal waveform. The difference in the distribution of normal Doppler waveform pattern between the patients and the control group was significant (P < 0.001). No differences were found in the behaviour of the hepatic vein Doppler waveform in relation to the different etiologic factors for FIL (P > 0.05). There was not any correlation between the degree of fat infiltration and the hepatic vein waveform pattern (P = 0.60). Conclusion: Patients with fatty liver has a high rate of an abnormal hepatic vein Doppler waveform pattern which can be biphasic or monophasic. We could not find a relation between the etiological factors for FIL and the occurrence of an abnormal HV Doppler waveform.

  8. Renal duplex Doppler ultrasound findings in diabetics

    Shim, Hyang Yee; Kim, Young Geun; Kook, Cheol Keu; Yoon, Chong Hyun; Lee, Shin Hyung; Lee, Chang Joon [National Medical Center, Seoul (Korea, Republic of)


    The correlation between clinical-laboratory findings and renal duplex Doppler ultrasound findings was studied in 45 patients with diabetes mellitus to see the role of duplex Doppler ultrasound in the detection of diabetic nephropathy. The resistive indices in patients with elevated serum creatinine, BUN, proteinuria, and systolic blood pressure levels were statistically significantly higher than those in patients with normal levels (p<0.05). Also resistive indics in patients with retinopathy were higher than that in patients without retinopathy (p<0.05). But the ultrasound morphologic changes of kidney such as renal length, cortical eye-catching, and corticomedullarycontrast were not well correlated with clinical-laboratory data and resistive index. The resistive index of the kidney in conjunction with clinical-laboratory data in diabetics may be helpful in the evaluation of diabetic nephropathy

  9. Effects of respiratory manoeuvres on hepatic vein Doppler waveform and flow velocities in a healthy population

    Altinkaya, Naime, E-mail: [Department of Radiology, Baskent University Medical School, Adana (Turkey); Baskent University, Faculty of Medicine, Department of Radiology, Adana (Turkey); Koc, Zafer, E-mail: [Department of Radiology, Baskent University Medical School, Adana (Turkey); Baskent University, Faculty of Medicine, Department of Radiology, Adana (Turkey); Ulusan, Serife, E-mail: [Department of Radiology, Baskent University Medical School, Adana (Turkey); Baskent University, Faculty of Medicine, Department of Radiology, Adana (Turkey); Demir, Senay, E-mail: [Department of Radiology, Baskent University Medical School, Adana (Turkey); Baskent University, Faculty of Medicine, Department of Radiology, Adana (Turkey); Gurel, Kamil, E-mail: [Department of Radiology, Baskent University Medical School, Adana (Turkey); Baskent University, Faculty of Medicine, Department of Radiology, Adana (Turkey)


    Objective: This study was performed to determine the variations in Doppler waveforms and flow velocity during respiratory manoeuvres in healthy individuals with no liver disease. Materials and methods: In total, 100 individuals (75 women and 25 men) without known cardiac or liver disease were examined prospectively with duplex Doppler ultrasonography (US). We recorded the Doppler waveforms and peak systolic velocities (V{sub max}) of the middle hepatic vein during normal respiration, during breath-holding after quiet expiration and also during deep inspiration. Doppler waveforms are categorised as triphasic, biphasic or monophasic. Results: During normal respiration, hepatic venous waveforms were triphasic in 93% of subjects, monophasic in 6% and biphasic in 1%. During breath-holding after quiet expiration, the percentages were 91%, 6% and 3%, respectively. During deep inspiration, they were 80%, 18% and 2%, respectively. Although significant differences were noted between rates during deep inspiration and normal respiration, they were quite similar during normal respiration and breath-holding after quiet expiration (P < 0.05). The values of V{sub max} were significantly higher during normal respiration compared to quiet expiration and during quiet expiration compared to deep inspiration (P < 0.05). Conclusion: The velocities and waveforms of hepatic veins varied during respiratory manoeuvres. The status of respiration must be taken into consideration whilst examining the hepatic vein waveforms and velocities with duplex Doppler US.

  10. Vascular waveform analysis of flap-feeding vessels using color Doppler ultrasonography.

    Ogino, Akihiro; Onishi, Kiyoshi


    We performed vascular waveform analysis of flap-feeding vessels using color Doppler ultrasonography and evaluated the blood flow in the flaps prior to surgery. Vascular waveform analysis was performed in 19 patients. The analyzed parameters included the vascular diameter, flow volume, flow velocity, resistance index, pulsatility index, and acceleration time. The arterial waveform was classified into 5 types based on the partially modified blood flow waveform classification reported by Hirai et al.; in particular, D-1a, D-1b, and D-2 were considered as normal waveforms. They were 4 patients which observed abnormal vascular waveform among 19 patients (D-4 : 1, D-3 : 1, and Poor detect : 2). The case which presented D-4 waveform changed the surgical procedure, and a favorable outcome was achieved. Muscle flap of the case which presented D-3 waveform was partially necrosed. The case which detected blood flow poorly was judged to be the vascular obstruction of the internal thoracic artery. In the evaluation of blood flow in flaps using color Doppler ultrasonography, determination of not only basic blood flow information, such as the vascular distribution and diameter and flow velocity, but also the flow volume, vascular resistance, and arterial waveform is essential to elucidate the hemodynamics of the flap.

  11. Doppler waveforms of the hepatic veins in children with diffuse fatty infiltration of the liver

    Uzun, Hakan [Duzce University School of Medicine, Department of Pediatrics, Konuralp, Duzce 81620 (Turkey); Yazici, Burhan [Duzce University School of Medicine, Department of Radiology, Konuralp, Duzce 81620 (Turkey)], E-mail:; Erdogmus, Besir [Duzce University School of Medicine, Department of Radiology, Konuralp, Duzce 81620 (Turkey); Kocabay, Kenan [Duzce University School of Medicine, Department of Pediatrics, Konuralp, Duzce 81620 (Turkey); Buyukkaya, Ramazan; Buyukkaya, Ayla; Yazgan, Omer [Duzce University School of Medicine, Department of Radiology, Konuralp, Duzce 81620 (Turkey)


    Objective: The aim of this study was to investigate the effect of fatty infiltration of the liver (FIL) on the Doppler waveform pattern in the hepatic veins of obese children. Methods: In this prospective study, 59 patients with diffuse FIL and 45 normal healthy children who served as control group underwent hepatic vein B-mod and duplex Doppler sonography. The Doppler sonography spectrum of the right hepatic vein was classified into three groups: triphasic waveform, biphasic waveform, and monophasic or flat waveform. Results: There was a statistically significant difference in the phasicity of hepatic venous flow between patients and control subjects (p < 0.001). The Doppler flow pattern in the right hepatic vein was triphasic in 28 (47.5%), biphasic in 28 (47.5%), and monophasic in 3 (5%) children with fatty liver, while it was triphasic in 43 (95.6%) and biphasic in 2 (4.4%) control subjects. There was an inverse correlation between the sonographic grade of fatty infiltration of the liver and the phasicity of hepatic venous flow (r = -0.479, p < 0.001). Conclusions: Abnormal right hepatic vein Doppler waveform, biphasic as well as monophasic, can be seen in healthy obese children with diffuse FIL.

  12. Echocardiographic evaluation of external iliac artery Doppler waveform in patients with coronary artery disease.

    Styczynski, Grzegorz; Szmigielski, Cezary; Kaczynska, Anna; Kuch-Wocial, Agnieszka


    Visual interpretation of the Doppler waveform in the common femoral or distal external iliac artery (EIA) was reported to be useful in screening for proximal peripheral artery occlusive disease (PAOD) in patients with lower limb ischemia. Commonly patients with coronary artery disease (CAD) referred for echocardiography have coexistent arterial pathology. Therefore, we decided to study whether echocardiographic evaluation of the distal EIA flow can be useful for detection of PAOD in patients with CAD. We studied 150 consecutive patients (pts) with CAD referred for echocardiography. At the end of an echocardiographic examination, evaluation of the flow in the distal EIA with an echocardiographic probe was performed. The Doppler waveform was classified as normal-with early diastolic flow reversal or abnormal-without early diastolic flow reversal. Echocardiographic findings were compared in a blinded fashion with the results of the ankle brachial index measurements (ABI). Based on the ABI ≤ 0.9, peripheral artery disease was diagnosed in 54 pts (36%) and abnormal external iliac Doppler waveform was found in 27 pts (18%). Sensitivity of abnormal external iliac Doppler waveform in predicting PAOD was 48%, specificity 99%, positive predictive value (PPV) 96%, and negative predictive value 77%. Peripheral arterial occlusive disease is common in patients with CAD referred for echocardiographic study. Echocardiographic assessment of distal EIA Doppler waveform has low sensitivity, but high specificity and high PPV in the diagnosis of peripheral arterial occlusive disease.

  13. Evaluation of factors influencing arterial Doppler waveforms in an in vitro flow phantom

    Sung, Chang Kyu [Dept. of Radiology, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul (Korea, Republic of); Lee, Kyoung Ho [Dept. of Radiology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam (Korea, Republic of); Kim, Seung Hyup [Dept. of Radiology and the Institute of Radiation Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul (Korea, Republic of)


    The aim of this study was to investigate factors that influence arterial Doppler waveforms in an in vitro phantom to provide a more accurate and comprehensive explanation of the Doppler signal. A flow model was created using a pulsatile artificial heart, rubber or polyethylene tubes, a water tank, and a glass tube. Spectral Doppler tracings were obtained in multiple combinations of compliance, resistance, and pulse rate. Peak systolic velocity, minimum diastolic velocity, resistive index (RI), pulsatility index, early systolic acceleration time, and acceleration index were measured. On the basis of these measurements, the influences of the variables on the Doppler waveforms were analyzed. With increasing distal resistance, the RI increased in a relatively linear relationship. With increasing proximal resistance, the RI decreased. The pulsus tardus and parvus phenomenon was observed with a small acceleration index in the model with a higher grade of stenosis. An increase in the distal resistance masked the pulsus tardus and parvus phenomenon by increasing the acceleration index. Although this phenomenon occurred independently of compliance, changes in the compliance of proximal or distal tubes caused significant changes in the Doppler waveform. There was a reverse relationship between the RI and the pulse rate. Resistance and compliance can alter the Doppler waveforms independently. The pulse rate is an extrinsic factor that also influences the RI. The compliance and distal resistance, as well as proximal resistance, influence the pulsus tardus and parvus phenomenon.

  14. The effect of nonuniform motion on the Doppler spectrum of scattered continuous-wave waveforms

    Gray, John E.; Addison, Stephen R.


    The Doppler effect is a widely treated phenomena in both radar and sonar for objects undergoing uniform motion. There are many different models (Censor has written a history of the subject) one can use to derive the Doppler effect. The treatment of non-uniform motion is not widely discussed in the literature of radar and sonar. Some authors argue it is negligible, while others refer to work dating back to Kelly in the early sixties. The treatment by Kelly, based on waveform analysis in acoustics, is difficult to justify in electromagnetism. Using the language of waveform analysis it is difficult to determine when approximations are justified by the physics of the waveform interaction and when they aren't. By returning to electromagnetic considerations in the derivation and subsequent analysis, issues associated with the correct physics and proper approximations become transparent. We present a straight forward analysis of the non-uniform Doppler effect based on the relativistic mirror (moving boundary) that is undergoing arbitrary motion. The resultant structure of the scattered waveform provides a simple representation of the effect of non-uniform motion on the scattered waveform that can be more easily analyzed. This work is a continuation of earlier work done by Censor, De Smedt, and Cooper. This analysis is independent of narrow-band assumptions so it is completely general. Non-uniform motion can produce two types of effects associated with the Doppler spectrum, a baseband line that isn't straight and micro-Doppler off of the baseband that produces complicated sideband behavior. Complicated baseband and micro-Doppler are illustrated by using the example of a particular waveform, the continuous wave (CW) which is analyzed for a number of examples of interest to the radar community. Application of this information is then discussed.

  15. Doppler flow velocity waveforms in the fetal cardiac outflow tract: Reproducibility of waveform recording and analysis

    I.A.L. Groenenberg (Irene); W.C.J. Hop (Wim); J.W. Wladimiroff (Juriy)


    markdownabstract__Abstract__ Reproducibility of flow velocity waveform recording and analysis was studied at fetal cardiac level (ductus arteriosus, pulmonary artery and ascending aorta) in 42 normal pregnancies. The flow velocity parameters studied were the peak systolic velocity (PSV),

  16. Unambiguous range-Doppler LADAR processing using 2 giga-sample-per-second noise waveforms

    Cole, Z. [S2 Corporation, 2310 University Way 4-1, Bozeman, MT 59715 (United States)]. E-mail:; Roos, P.A. [Spectrum Lab, Montana State University, P.O. Box 173510, Bozeman, MT 59717 (United States); Berg, T. [S2 Corporation, 2310 University Way 4-1, Bozeman, MT 59715 (United States); Kaylor, B. [S2 Corporation, 2310 University Way 4-1, Bozeman, MT 59715 (United States); Merkel, K.D. [S2 Corporation, 2310 University Way 4-1, Bozeman, MT 59715 (United States); Babbitt, W.R. [Spectrum Lab, Montana State University, P.O. Box 173510, Bozeman, MT 59717 (United States); Reibel, R.R. [S2 Corporation, 2310 University Way 4-1, Bozeman, MT 59715 (United States)


    We demonstrate sub-nanosecond range and unambiguous sub-50-Hz Doppler resolved laser radar (LADAR) measurements using spectral holographic processing in rare-earth ion doped crystals. The demonstration utilizes pseudo-random-noise 2 giga-sample-per-second baseband waveforms modulated onto an optical carrier.

  17. Changes in superior mesenteric artery Doppler waveform during reduction of cardiac stroke volume and hypotension

    Perko, M J; Perko, Grazyna; Just, S


    Influence of stroke volume reduction and hypotension on the superior mesenteric artery (SMA) Doppler waveform was evaluated during head-up tilt-induced central hypovolemia in 11 healthy volunteers. During normotensive reduction in stroke volume, peak systolic velocity (pV), mean velocity, pulsati......Influence of stroke volume reduction and hypotension on the superior mesenteric artery (SMA) Doppler waveform was evaluated during head-up tilt-induced central hypovolemia in 11 healthy volunteers. During normotensive reduction in stroke volume, peak systolic velocity (pV), mean velocity...... of the study indicate that alterations in stroke volume induce consequential changes in the SMA Doppler waveform. These changes originate from both direct influence of stroke volume and/or pressure on blood flow velocity, and alterations in SMA peripheral resistance that follow variations in stroke volume....... Presented interdependencies should be taken into consideration while studying mesenteric physiology with the use of Doppler technique and while interpreting the duplex results in patients suffering from diseases that may influence flow velocity and mimic or obscure Doppler effects of the SMA stenosis....

  18. Radar Sensor Networks: Algorithms for Waveform Design and Diversity with Application to ATR with Delay-Doppler Uncertainty

    Qilian Liang


    Full Text Available Automatic target recognition (ATR in target search phase is very challenging because the target range and mobility are not yet perfectly known, which results in delay-Doppler uncertainty. In this paper, we firstly perform some theoretical studies on radar sensor network (RSN design based on linear frequency modulation (LFM waveform: (1 the conditions for waveform coexistence, (2 interferences among waveforms in RSN, (3 waveform diversity in RSN. Then we apply RSN to ATR with delay-Doppler uncertainty and propose maximum-likeihood (ML ATR algorithms for fluctuating targets and nonfluctuating targets. Simulation results show that our RSN vastly reduces the ATR error compared to a single radar system in ATR with delay-Doppler uncertainty. The proposed waveform design and diversity algorithms can also be applied to active RFID sensor networks and underwater acoustic sensor networks.

  19. Power doppler ultrasound findings of renal infarct after experimental renal artery occlusion: comparison with spiral CT

    Jung, Seung Eun; Shinn, Kyung Sub; Kim, Hak Hee; Mun, Seok Hwan; Lee, Young Joon; Lee, Bae Young; Choi, Byung Gil; Lee, Jae Mun; Lee, Hee Jeong [The Catholic University of Korea College of Medicine, Seoul (Korea, Republic of)


    To evaluate the efficacy of power Doppler ultrasonography (PDUS) in depicting renal infarction in rabbits during experimental renal segmental arterial occlusion, and to compare the results with those of CT scanning. In 28 rabbits weighing 2.5 4kg, the segmental renal artery was occluded through the left main renal artery by embolization with Ivalon (Nycomed, Paris, France). Power Doppler ultrasonography and spiral CT scanning were performed before and at 2, 5, 8, 15, and 24 hours, and 3 and 7 days after occlusion of the segmental renal artery. The location of infarcted areas and collaterals, as seen on PDUS and CT scans, was evaluated by two radiologists. In all cases, as seen on power Doppler ultrasonography, infarcted areas-when compared with normal parenchyma, clearly demonstrated wedge-shaped perfusion defects in the kidney. The location of the lesion closely corresponded to the location seen during CT scanning. After renal arterial occlusion, transiently congested capsular arteries, which were named 'capsular sign', were seen in 63% of rabbits in the two and five-hour groups. No significant cortical rim sign was demonstrated on power Doppler ultrasonography, though it was noted on spiral CT at 15 and 24 hours, and 3 and 7 days after renal arterial occlusion. Power Doppler ultrasonography was useful for the diagnosis of renal infarction. Congested capsular artery seen in the early stage of renal infarction might be a characteristic finding of this condition, as seen on power Doppler ultrasonography.


    Sheng Cai; Guang-xi Zhong; Jian-chu Li; Yu Xia; Hui-jun Li; Yu-xin Jiang


    Objective To evaluate color Doppler ultrasonography (CDU) appearances of renal vein thrombosis (RVT) and its diagnostic value.Methods Ten patients with RVT were analyzed retrospectively. Renal structure, distributions of intrarenal flow signals, echogenicity, and flow fullness in main renal veins were observed with CDU. Resistance index (RI) was recorded from the waveforms of segmental or interlobar renal artery.Results Ten kidneys in nine patients were confirmed to have thrombus within the main renal veins, and one patient was confirmed to have thrombus within the small intrarenal veins. The appearances of the main renal vein thrombosis included full of solid echogenicity or strip echogenicity and complete or partial filling defect within the main renal veins, and absent or a few intrarenal venous flow signals in 70% of kidneys involved. The appearances of intrarenal vein thrombosis included obscure renal structure and no venous flow signal within the involved part of the kidneys. Reverse diastolic flow in the intrarenal artery had only a sensitivity of 36% (4/11) ; in other 7 kidneys without intrarenal arterial reverse diastolic flow, increased RI (mean, 0.84; range, 0.74-0.96) was found.Conclusion CDU is helpful for rapid clinical diagnosis and follow-up of RVT, and therefore can be the first imaging modality of choice for RVT.

  1. Doppler spectrum analysis to diagnose rejection during posttransplant acute renal failure.

    Merkus, J W; Hoitsma, A J; van Asten, W N; Koene, R A; Skotnicki, S H


    During posttransplant acute renal failure (ARF), the diagnosis of allograft rejection constitutes a major problem. We evaluated the value of Doppler ultrasonography in identifying grafts at risk of rejection during ARF. In 184 recipients of a renal allograft, Doppler examinations were performed on the first and fifth postoperative day. Doppler spectra were quantitatively analyzed with a user-written computer program. Doppler findings were not used in clinical decision making. ARF was defined as a diuresis cadaveric grafts (n = 123), while living related donor grafts (n = 20) showed a lower RI (0.55 +/- 0.07; P 4 days (n = 24), RI was not significantly different (0.63 +/- 0.07 vs. 0.68 +/- 0.15; NS). However, the acceleration time of the systolic deflection of the spectrum waveform (Tmax) was shorter in grafts with ARF > 4 days (86 +/- 47 msec vs. 128 +/- 39 msec; P 4 days (n = 24) showed a Tmax or = 90 msec, only 2 rejections occurred (negative predictive value, 13/15 = 87%). For the RI (> 0.85), positive predictive value was 4/5 = 80% and negative predictive value (RI identification of patients at risk for rejection and in the timing of allograft biopsy during ARF. Persistently short Tmax values on the fifth day after transplantation perform better in identifying grafts at risk of rejection than high RI values.

  2. The US color Doppler in acute renal failure.

    Nori, G; Granata, A; Leonardi, G; Sicurezza, E; Spata, C


    Imaging techniques, especially ultrasonography and Doppler, can give an effective assistance in the differential diagnosis of acute renal failure (ARF). An resistance Index (RI) value >0.75 is reported as optimal in attempting differential diagnosis between acute tubular necrosis (ANT) and prerenal ARF. In hepatorenal syndrome (HRS) RIs is very increased. In some renal vasculitis, as nodose panarteritis (PN), hemolytic-uremic syndrome (HUS), thrombotic thrombocytopenic purpura (TTP), parenchymal perfusion is reduced and RI increased. In lupus nephritis the RI values are correlated with creatinine level and normal RI are considered as a good prognostic tool. In acute primitive or secondary glomerulonephritis (GN), RI value is normal, with diffuse parenchymal hypervascularization. In acute crescentic and proliferative GN and tubulo-interstitial disease, color Doppler (CD) and power Doppler (PD) reveal a decreased renal parenchymal perfusion, which correlates with increased RI values. In acute thrombosis of renal artery, US color Doppler (DUS) reveals either an absence of Doppler signal or a tardus-parvus pulse distal to the vascular obstruction. In this situation it is possible to visualize hyperthropic perforating vessels that redirect their flow from the capsular plexus to the renal parenchyma. In acute thrombosis of the renal vein Doppler analysis of parenchymal vessels reveals remarkable RI values, sometimes with reversed diastolic flow. In postrenal ARF an adjunct to the differentiation between obstruction and non obstructive dilatation can be found through RIs. Diagnostic criteria of obstruction as reported by literature are: RI>0.70 in the obstructed kidney and, mostly, a difference in RI between the 2 kidneys >0.06-0.1.

  3. Performance bounds on micro-Doppler estimation and adaptive waveform design using OFDM signals

    Sen, Satyabrata; Barhen, Jacob; Glover, Charles W.


    We analyze the performance of a wideband orthogonal frequency division multiplexing (OFDM) signal in estimating the micro-Doppler frequency of a target having multiple rotating scatterers (e.g., rotor blades of a helicopter, propellers of a submarine). The presence of rotating scatterers introduces Doppler frequency modulation in the received signal by generating sidebands about the transmitted frequencies. This is called the micro-Doppler effects. The use of a frequency-diverse OFDM signal in this context enables us to independently analyze the micro-Doppler characteristics with respect to a set of orthogonal subcarrier frequencies. Therefore, to characterize the accuracy of micro-Doppler frequency estimation, we compute the Craḿer-Rao Bound (CRB) on the angular-velocity estimate of the target while considering the scatterer responses as deterministic but unknown nuisance parameters. Additionally, to improve the accuracy of the estimation procedure, we formulate and solve an optimization problem by minimizing the CRB on the angular-velocity estimate with respect to the transmitting OFDM spectral coefficients. We present several numerical examples to demonstrate the CRB variations at different values of the signal-to-noise ratio (SNR) and the number of OFDM subcarriers. The CRB values not only decrease with the increase in the SNR values, but also reduce as we increase the number of subcarriers implying the significance of frequency-diverse OFDM waveforms. The improvement in estimation accuracy due to the adaptive waveform design is also numerically analyzed. Interestingly, we find that the relative decrease in the CRBs on the angular-velocity estimate is more pronounced for larger number of OFDM subcarriers.

  4. Performance Bounds on Micro-Doppler Estimation and Adaptive Waveform Design Using OFDM Signals

    Sen, Satyabrata [ORNL; Barhen, Jacob [ORNL; Glover, Charles Wayne [ORNL


    We analyze the performance of a wideband orthogonal frequency division multiplexing (OFDM) signal in estimating the micro-Doppler frequency of a target having multiple rotating scatterers (e.g., rotor blades of a helicopter, propellers of a submarine). The presence of rotating scatterers introduces Doppler frequency modulation in the received signal by generating sidebands about the transmitted frequencies. This is called the micro-Doppler effects. The use of a frequency-diverse OFDM signal in this context enables us to independently analyze the micro-Doppler characteristics with respect to a set of orthogonal subcarrier frequencies. Therefore, to characterize the accuracy of micro-Doppler frequency estimation, we compute the Cram er-Rao Bound (CRB) on the angular-velocity estimate of the target while considering the scatterer responses as deterministic but unknown nuisance parameters. Additionally, to improve the accuracy of the estimation procedure, we formulate and solve an optimization problem by minimizing the CRB on the angular-velocity estimate with respect to the transmitting OFDM spectral coefficients. We present several numerical examples to demonstrate the CRB variations at different values of the signal-to-noise ratio (SNR) and the number of OFDM subcarriers. The CRB values not only decrease with the increase in the SNR values, but also reduce as we increase the number of subcarriers implying the significance of frequency-diverse OFDM waveforms. The improvement in estimation accuracy due to the adaptive waveform design is also numerically analyzed. Interestingly, we find that the relative decrease in the CRBs on the angular-velocity estimate is more pronounced for larger number of OFDM subcarriers.

  5. Changes in Doppler waveforms can predict pressure reduction across internal carotid artery stenoses

    Sillesen, H; Schroeder, T


    perfusion pressure. Forty-nine patients were examined consecutively with ultrasound Doppler prior to carotid endarterectomy. Pulsatility index (PI), pulse rise-time (RT), and systolic width (SW) were related to angiographic degree of stenosis and the ratio of distal ICA blood pressure to common carotid...... artery (CCA) blood pressure (ICA/CCA pressure ratio). The latter was determined during surgery. All three waveform parameters were significantly correlated with the ICA/CCA pressure ratio when calculated from the mean frequency curve (p less than 0.001). A reduction in ICA pressure of 20% could...

  6. Hepatic vein spectral doppler waveform in patients with fatty liver changes – a study from Western nepal

    Manish Kiran ShresthMBBS, MD, a


    Full Text Available Background: Spectral Doppler waveform interpretation of hepatic vein is of considerable importance as it mirrors cardiac and hepatic physiology. The aim of this study was to evaluate the flow velocity waveform pattern in patients with different grades of fatty infiltration of liver and compare them with normal individuals. Methods: This was a prospective study carried out in 213 patients, taking 100 patients as “control” groups; and 113 “cases” with varying degree of fatty liver graded by ultrasonography. The patients included asymptomatic individuals with no history of cardiac, hepatic disease or alcohol intake. The study also excluded cases with any medical disease such as ascitis that could influence the outcome of hepatic Doppler measurement. The Doppler hepatic waveform of the right hepatic vein was taken and classified as triphasic, biphasic and monophasic. Results: All except one of the control group had normal triphasic pattern. Patients with severe grade of hepatic steatosis (Grade III showed monophasic flow in 72.2% of the cases with sensitivity and specificity amounting to 83.3 and 87.7 respectively. A significant difference was observed in distribution of Doppler waveform pattern (p= 0.00001. Conclusion: Triphasic waveform pattern was seen in majority of normal individuals with no cardiac or hepatic disease, while, in patients with increasing grade of hepatic steatosis, the waveform changed to biphasic and monophasic pattern due to decreased compliance of the hepatic veins.

  7. Renal Power Doppler Ultrasonographic Evaluation of Children With Acute Pyelonephritis

    Ali Pahlusi


    Full Text Available Urinary tract infections are common in children. The available gold standard method for diagnosis, Tc-99m dimercaptosuccinic acid scan is expensive and exposes patients to considerable amount of radiation. This study was performed to compare and assess the efficacy of Power Doppler Ultrasound versus Tc-99m DMSA scan for diagnosis of acute pyelonephritis. A quasi experimental study was conducted on 34 children with mean age of 2.82.7 years who were hospitalized with their first episode of febrile urinary tract infection. All children were evaluated in the first 3 days of admission by Doppler Ultrasound and Tc-99m DMSA scan. Patients with congenital structural anomalies were excluded. Each kidney was divided into three zones. The comparison between efficacy of Doppler Ultrasound and DMSA scan was carried out based on number of patients and on classified renal units. Based on the number of patients enrolled; the sensitivity, specificity, positive and negative predictive values and accuracy of Doppler Ultrasound were 89%, 53%, 70%, 80% and 74%, respectively but based on the renal units, it was 66%, 81%, 46%, 91% and 79% , respectively. Although Doppler Ultrasound has the potential for identifying acute pyelonephritis in children, but it is still soon to replace DMSA scan.

  8. Changes in uterine artery Doppler flow velocity waveforms during the third stage of labor.

    Maymon, R; Herman, A; Halperin, R; Bukovsky, I; Weinraub, Z; Ariely, S


    Transabdominal Doppler velocity waveform measurements of the uterine arteries during the third stage of labor were performed upon 25 patients with uncomplicated vaginal deliveries and 5 with prolonged third stage in order to further assess third-stage mechanisms. Based on Doppler flow measurements, three phases of the third stage of labor were observed: (1) a latent phase with a systolic/diastolic ratio (S/D) and a pulsatility index (PI) of 2.14 +/- 0.49 and 0.89 +/- 0.17, respectively; (2) a contraction and detachment phase with an S/D and PI of 2.53 +/- 0.53 and 1.28 +/- 0.37, respectively, and (3) an expulsion phase with an S/D and PI of 2.20 +/- 0.34 and 0.91 +/- 0.20, respectively (p contractions squeezed the uterine vessels as they traversed the myometrium, leading to an increase in the extrinsic resistance, which was reflected by high resistance flow. Following placental separation and changes in the placental-site wall, there was slight uterine relaxation resulting in decreased uterine vessel resistance. This observation encourages the authors to continue investigating the contribution of ultrasound and Doppler flow for studies of the postpartum period.

  9. Adaptive OFDM Radar Waveform Design for Improved Micro-Doppler Estimation

    Sen, Satyabrata [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Engineering Science Advanced Research, Computer Science and Mathematics Division


    Here we analyze the performance of a wideband orthogonal frequency division multiplexing (OFDM) signal in estimating the micro-Doppler frequency of a rotating target having multiple scattering centers. The use of a frequency-diverse OFDM signal enables us to independently analyze the micro-Doppler characteristics with respect to a set of orthogonal subcarrier frequencies. We characterize the accuracy of micro-Doppler frequency estimation by computing the Cramer-Rao bound (CRB) on the angular-velocity estimate of the target. Additionally, to improve the accuracy of the estimation procedure, we formulate and solve an optimization problem by minimizing the CRB on the angular-velocity estimate with respect to the OFDM spectral coefficients. We present several numerical examples to demonstrate the CRB variations with respect to the signal-to-noise ratios, number of temporal samples, and number of OFDM subcarriers. We also analysed numerically the improvement in estimation accuracy due to the adaptive waveform design. A grid-based maximum likelihood estimation technique is applied to evaluate the corresponding mean-squared error performance.

  10. Determination of Doppler Middle Cerebral Artery Waveform Indices in Normal 20 – 40 Weeks Pregnancies

    S. Vahdinia


    Full Text Available Background/Objective: The aim of prenatal evaluation is to prevent fetal death. One of the main methods of evaluation of fetus health before delivery is Doppler flow velocity waveform analysis of fetus vessels. Increasing of resistance in fetal circulatory system causes the preferential shunt of blood flow from non-critical organs toward critical organs such as brain. The increase in brain blood flow leads to reduction of brain vessels resistance and results in changes of fetal cerebral arteries Doppler flow velocity indices. Evaluation of Doppler wave of middle cerebral artery can predict most of the at risk fetuses in high-risk pregnancies."nIn this study we tried to obtain normal value (and their changes across the progress of pregnancy of Doppler flow velocity indices (PI, RI, S/D ratio and PSV of middle cerebral artery in 20 - 40 weeks normal pregnancies in an Iranian population and evaluate the effect of fetus heart rate according to the above mentioned indices."nPatients and Methods: In this cross section study, 400 pregnant women with normal pregnancies and gestational age between 20 to 40 weeks were studied about middle cerebral artery Doppler examination. Mothers with preeclampsia, diabetes mellitus, hypertension, abnormal uterine bleeding, induction ovulation, multifetal pregnancy, major fetal anomalies, history of LD or any other OCP usage and intra uterine growth retardation were excluded from the study. All cases were evaluated by gray scale ultrasonography initially and then a Doppler study of middle cerebral artery was done."nResults: According to the results of this study, with progression of pregnancy PI, RI, S/D ratio values decrease and PSV value increases in middle cerebral artery. These changes were statistically significant and were more characteristic during late weeks of pregnancy. In addition, mean fetal heart rate had been significantly reduced with pregnancy progression."nConclusion: Values of RI, PI, S/D ratio and

  11. Comparison between doppler ultrasonography and renal scintigraphy in assessment of post-transplant renal function

    Yoon, Yeo Chang; Shin, Byung Seok; Ohm, Joon Young; Kim, Seong Min; Ahn, Moon Sang; Yang, Shin Seok [Chungnam National University Hospital, Daejeon (Korea, Republic of); Park, Mi Hyun [Dept. of Radiology, Dankook University Hospital, Cheonan (Korea, Republic of)


    To compare the usefulness of Doppler ultrasonography and renal scintigraphy in the assessment of short- and long-term function of transplanted kidneys. We retrospectively reviewed the cases of 79 patients who underwent Doppler ultrasonography and technetium-99m diethylene triamine pentaacetic acid renal scintigraphy on the same day, within 4 days of renal transplantation. Image parameters were evaluated for statistical differences. There was a strong positive correlation between the glomerular filtration rate (GFR) as measured by renal scintigraphy and the estimated GFR (eGFR) based on serum creatinine levels (correlation coefficient = 0.71). Scan grade according to the time-activity curve, resistive index, and end diastolic velocity showed moderate correlations with the eGFR (correlation coefficients = -0.557, -0.329, and 0.370, respectively) in the early post-transplantation period. The mean survival time was longer in patients with lower resistive indices (≤ 0.68, 54.9 months vs. > 0.68, 29.5 months) and lower pulsatility indices (≤ 1.32, 53.8 months vs. > 1.32, 28.7 months); however, there were no statistically significant differences in the long-term follow-up period (p = 0.121 for resistive index and p = 0.074 for pulsatility index). Renal scintigraphy is a more sensitive method than Doppler ultrasonography for assessing transplanted kidney function in the early post-transplantation period. Doppler ultrasonography might reflect the long-term survival time. However, it is difficult to predict long-term renal function using either method.

  12. The influence of maternal undernutrition in ovine twin pregnancy on fetal growth and Doppler flow-velocity waveforms.

    Newnham, J P; Kelly, R W; Patterson, L; James, I


    The effects on placental blood flow velocity of maternal undernutrition during mid pregnancy were investigated in 38 twin bearing pregnant sheep by Doppler analysis of umbilical and uteroplacental arterial waveforms. Mid pregnancy undernutrition resulted in fetal growth restriction manifest at term gestation by reduced mean birth weight. Arterial waveform systolic/diastolic ratios from the umbilical and uteroplacental arterial circulations were not influenced by maternal nutrition either during the dietary deprivation or during a subsequent period of dietary supplementation. An effect of heart rate on systolic/diastolic ratios could not be demonstrated. The results indicate that the fetus responds to mid pregnancy maternal undernutrition with restricted growth but without alterations in systolic/diastolic ratios in umbilical or uteroplacental arterial waveforms.

  13. Evaluation of renal artery stenosis using color Doppler sonography in young patients with multiple renal arteries

    QIN Wei; ZHANG Xin; YANG Min; ZHONG Xu-hui; ZHAO Ming-hui


    Background Some individuals have multiple renal arteries. Severe stenosis in one of the arteries may cause refractory hypertension. The detection of stenosis within one of the multiple renal arteries usually required invasive procedures, such as computed tomographic angiography (CTA) and magnetic resonance angiography (MRA). This study reported the application of color Doppler sonography (CDS) in the detection of severe stenosis in one of the multiple arteries.Methods Patients with multiple renal arteries and one of the arteries with severe stenosis were retrospectively studied. Peak systolic velocities (PSV) of renal arteries and the intrarenal CDS patterns were collected and compared. The diagnosis was confirmed by digital subtraction angiography (DSA).Results Four children with multiple renal arteries and one of the arteries with stenosis were investigated. They were admitted due to refractory hypertension. CDS screening identified two renal arteries in one kidney of each patient with one of the two renal arteries having stenosis >70%. The PSV of the stenosed arteries were much higher, and the intrarenal CDS patterns supplied by the stenosed arteries changed into T-P patterns.Conclusion Non-invasive CDS technology may be a useful method to identify severe stenosis in one of multiple renal arteries in young patients.

  14. Placental disease and abnormal umbilical artery Doppler waveforms in trisomy 21 pregnancy: A case-control study.

    Corry, Edward; Mone, Fionnuala; Segurado, Ricardo; Downey, Paul; McParland, Peter; McAuliffe, Fionnuala M; Mooney, Eoghan E


    The objectives of this study were firstly to determine the proportion of placental pathology in fetuses affected by trisomy 21 (T21) using current pathological descriptive terminology and secondly to examine if a correlation existed between the finding of an abnormal umbilical artery Doppler (UAD) waveform, the presence of T21 and defined placental pathological categories. This case-control study assessed singleton fetuses with karyotypically confirmed trisomy 21 where placental histopathology had been conducted from 2003 to 2015 inclusive, within a university tertiary obstetric centre. This was compared with unselected normal singleton control pregnancies matched within a week of gestation at delivery. Data included birthweight centiles and placental histopathology. Comparisons of Doppler findings across placental pathological categories were performed using statistical analysis. 104 cases were analysed; 52 cases of trisomy 21 and 52 controls. Fetal vascular malperfusion (48.1% vs. 5.8%, p = 0.001) and maturation defects (39.2% vs. 15.7%, p = 0.023) were more common in trisomy 21 placentas. Compared with controls, trisomy 21 fetuses were more likely to have shorter umbilical cords (p = 0.001) and had more UAD abnormalities. Amongst T21 pregnancies, umbilical artery Doppler abnormalities are associated with the presence of maternal vascular malperfusion. Fetal vascular malperfusion and maturation defects are more common in trisomy 21 placentas. Abnormal umbilical artery Doppler waveforms are more common in T21 and are associated with maternal vascular malperfusion. Placental disease may explain the increased rate of intrauterine death in T21. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Contrast-enhanced power Doppler US in the diagnosis of renal pseudotumors.

    Ascenti, G; Zimbaro, G; Mazziotti, S; Gaeta, M; Lamberto, S; Scribano, E


    The term "pseudotumor" is used to refer to several anatomic variants that can simulate a renal mass, the most frequent of which are hypertrophied column of Bertin, persistence of fetal lobation, and the dromedary or splenic hump. We describe the findings of power Doppler US after the ultrasound contrast agent (Levovist, Schering, Berlin, Germany) administration in 4 patients with a renal focal lesion in whom gray-scale and baseline power Doppler US was not able to certainly differentiate pseudotumor from neoplasm.

  16. Doppler Ultrasound in Chronic Renal Allograft Dysfunction : Can Acute Rejection be Predicted

    Kim, Eun Kyung; Kim, Myeong Jin; Lee, Jong Tae; Yoo, Hyung Sik; Kim, Ki Whang; Park, Ki Ill; Chung, Hyun Joo [Yonsei University College of Medicine, Seoul (Korea, Republic of)


    To investigate Doppler sonographic findings valuable for detecting acute rejection in transplanted kidney with chronic allograft dysfunction. Forty-three renal allografts who underwent renal Doppler sonography and renal biopsy due to chronic allograft dysfunction were included. According to histopathologic findings, patients were classified into 2 groups: chronic component only(group 1, n=30) and acute rejection with or without chronic component 2 groups were performed. No definite difference in radio of renal size, cortical echogenecity, corticomedullary differentiation was noted between group 1 and group 2.Resistive index was 0.61{+-}0.18 in group 1 and 0.64{+-}0.22 in group 2, which showed no statistically significant difference. Characteristic Doppler sonographic findings suggesting acute rejection in cases of chronic allograft dysfunction were not found inauther's study. Therefore, minimal invasive renal biopsy to determine histopathologic status of transplanted kidney is essential in evaluation of the chronic allograft dysfunction

  17. Ultrasonic Doppler measurement of renal artery blood flow

    Freund, W. R.; Beaver, W. L.; Meindl, J. D.


    Studies were made of (1) blood flow redistribution during lower body negative pressure (LBNP), (2) the profile of blood flow across the mitral annulus of the heart (both perpendicular and parallel to the commissures), (3) testing and evaluation of a number of pulsed Doppler systems, (4) acute calibration of perivascular Doppler transducers, (5) redesign of the mitral flow transducers to improve reliability and ease of construction, and (6) a frequency offset generator designed for use in distinguishing forward and reverse components of blood flow by producing frequencies above and below the offset frequency. Finally methodology was developed and initial results were obtained from a computer analysis of time-varying Doppler spectra.

  18. Software-defined radar and waveforms for studying micro-Doppler signatures

    Liu, Baokun; Chen, Rachel


    In this paper, we investigate the use of software defined radar (SDR) to analyze the micro-Doppler signatures. The first SDR we use is based on the Universal Software Radio Peripheral (USRP) and GNU Radio, and another SDR which has several operation modes is based on field-programmable gate arrays (FPGA). Typically, the USRP-based SDR is not optimized for radar applications due to its narrow bandwidth and time-varying additional delay caused by USRP components and operating system. The FPGA-based SDR is more suitable for applications where high-resolution range information is required. Our studies indicate that both of the SDR systems are capable of producing the micro-Doppler signatures. System design challenges and measurement results will be discussed in detail.

  19. [Determining the aortic and renal hemodynamic effects of propofol on rabbits using Doppler ultrasonography].

    Apan, Alpaslan; Karadeniz Bilgili, M Yasemin; Cağlayan, Fatma


    The hemodynamic effects of propofol-fentanyl anesthesia were known to reduce arterial pressure and heart rate. We aimed to determine the effects of propofol-fentanyl anesthesia on renal artery blood flow and aorta by using Doppler ultrasonography on an animal model. The study was conducted on 8 male New Zaeland White strain rabbits. The initial aortic and renal hemodynamic measurements were determined on animals using ketamin anesthesia. Later the right femoral arteries were cannulated for determining arterial blood pressure and pulse oximetry was followed from the ear. Propofol 5-7 mg/kg with fentanyl 1-2 microg/kg was injected via the ear vein. Doppler parameters (RI, RI, Vmax, Vmin) of the renal artery and aorta were determined after the anesthesia. According to the basal measurements, arterial blood pressure and breath rates declined significantly (27% and 53% respectively, p<0.05); however there were no statistical alteration of aortic and renal artery Doppler parameters. Anesthesia induced by propofol-fentanyl did not induce a statistically significant difference in Doppler parameters obtained from the renal artery and aorta. It is clinically important to know that determining the changes in RI and PI during the postoperative period is not related to the propofol-fentanyl anesthesia.

  20. Coefficient of variation: a powerful Doppler ultrasonographic parameter for detection of renal artery stenosis.

    Eibenberger, K; Schima, H; Trubel, W; Temel, T; Schmidt, C; Scherer, R; Windberger, U; Dock, W; Grabenwöger, F


    The aim of our study was to objectively compare the effectiveness of various Doppler parameters in the diagnosis of renal artery stenosis. In three sheep, variable degrees of renal artery stenosis were induced and renal segmental arteries were investigated using pulsed Doppler sonography. In each animal the standard deviation of the instantaneous peak velocity within one cardiac cycle normalized by the mean peak velocity (coefficient of variation) had significantly higher normalized regression coefficients (k* = -0.215, average of three animals) when compared to resistive index (k* = -0.090) and acceleration index (k* = -0.069). In each individual animal, coefficient of variation detected lower pressure gradients (6.3 mm Hg, average value) than did resistive index (13.4 mm Hg) or acceleration index (17.3 mm Hg). The coefficient of variation may detect the presence of pressure gradients in renal artery stenosis more accurately than acceleration index or resistive index.

  1. Doppler ultrasound study of penis in men with systemic sclerosis: a correlation with Doppler indices of renal and digital arteries.

    Rosato, E; Barbano, B; Gigante, A; Cianci, R; Molinaro, I; Quarta, S; Digiulio, M A; Messineo, D; Pisarri, S; Salsano, F


    Erectile dysfunction (ED) prevalence in male systemic sclerosis (SSc) is high and its pathogenesis is unclear. The aim of the study is to assess correlation between Doppler ultrasound indices of penis and kidneys or digital arteries in male systemic sclerosis. Fourteen men with systemic sclerosis were enrolled in this study. Erectile function was investigated by the International Index of Erectile Function-5. Peak systolic velocity, end diastolic velocity, resistive index, pulsative index, and systolic/diastolic ratio were measured on the cavernous arteries at the peno-scrotal junction in the flaccid state, on the interlobar artery of both kidneys and all ten proper palmar digital arteries. Ten (71 percent) patients have an International Index of Erectile Function-5 less than 21. Reduction of penis peak systolic velocity was observed in all SSc subjects. Doppler indices of cavernous arteries correlate with the International Index of Erectile Function-5. The renal and digital arteries resistive index demonstrated a good correlation (p less than 0.0001) with International Index of Erectile Function-5. A positive correlation exists between penis and kidney arteries Doppler indices: end diastolic velocity (p less than 0.05, r=0.54), resistive index (p less than 0.0001, r=0.90), systolic/diastolic ratio (p less than 0.01, r=0.69). A positive correlation was observed between penis and digital arteries Doppler indices: peak systolic velocity (p less than 0.01, r=0.68), end diastolic velocity (p less than 0.01, r=0.75), resistive index (p less than 0.001, r=0.79), systolic/diastolic ratio (p less than 0.05, r=0.59). A correlation exists between arterial impairment of penis and renal or digital arteries.

  2. Usefulness of Doppler Parameter in Patients with Renal Transplantation

    Yoon, Yeo Chang; Shin, Byung Seok; Ohm, Joon Young; Ahn, Moon Sang [Chungnam National University Hospital, Daejeon (Korea, Republic of); Park, Mi Hyun [Dept. of Radiology, Dankook University Hospital, Cheonan (Korea, Republic of); Kim, Ho Jun [Dept. of Radiology, Konyang University Hospital, Daejeon (Korea, Republic of)


    The purpose of this study is to assess the usefulness of Doppler parameters in transplanted kidney function. Doppler parameters, including resistive index (RI), pulsatility index (PI), peak systolic velocity (PSV), and end diastolic velocity (EDV) were measured in the interlobar artery of 55 transplant recipients. Patients were grouped according to glomerular filtration rate (GFR): Group A (GFR < 30 ml / min / 1.73 m2, n = 27) and group B (GFR {>=}30 ml / min / 1.73 m2, n = 28). Doppler parameters were compared between groups and correlated with the GFR. GFR (40.1 {+-} 26.9) showed a significant negative correlation with RI (0.69{+-}.08) (p = .002, r = -.414). RI (0.72 vs. 0.67), PI (1.42 vs. 1.23), and EDV (10.5 vs. 15.3) differed significantly between groups (p < .05), however, PSV was not (36.9 vs. 47.1). Patients in group A (n = 11) with a lower RI than the mean had significantly lower PSV (31.7 vs. 45.1; p = .027) and EDV (11.1 vs. 16.7; p .017), compared with such patients in group B (n = 21). Doppler parameters are useful for evaluation of function of transplanted kidney. Even if the RI is normal, PSV and EDV may be used as hemodynamic indicators.


    Chetana R


    Full Text Available One of the major factors affecting nephrogenesis in utero is intrauterine growth restriction (IUGR. Few studies showed reduced weight of the fetal kidney in IUGR fetuses as compared to normally grown fetuses. Reduced blood flow to the kidneys due to fetal hypoxemia in IUGR f o etus leads to increased pulsatility index which is likely to be responsible for impaired nephrogenesis and decreased kidney volume. AIMS AND OBJECTIVE : To estimate if fetal renal artery Doppler could affect fetal renal volume in healthy and growth restricted fetuses after 26 weeks of gestation. STUDY DESIGN AND SETTING : Cross sectional study carried out in the De partment radio diagnosis, Lata M angeshkar hospital, Nagpur, Maharashtra, India. MATERIAL AND METHOD S : Total 336 patients, which consisted of 309 norma lly grown fetuses and 27 intrauterine growth restricted fetuses were included in the study. Fetal renal volume of individual kidney, combined renal volume and relative renal volumes were calculated using 2 dimensional ultrasound for normal and IUGR fetuses . Fetal renal artery parameters particularly renal arterial pulsatility index were calculated for both the groups. Correlation of fetal renal Doppler parameters with renal volume was estimated for respective groups. RESULTS: Combined kidney volume was sign ificantly reduced in growth restricted fetuses than normal fetuses i.e. mean combined kidney volume for growth restricted fetuses was 12.6cc and for normal fetuses was 19.29cc. Most of the fetal biometric indices were positively correlated with the combine d kidney volume. Increased pulsatility index was seen in growth restricted fetuses i.e. on right side 1.37+/ - 0.35 and on left 1.40+/ - 0.35 i.e. >1 while for normal fetuses was 0.88 +/ - 0.08 on either side i.e. <1. Considerable negative correlation was found between fetal renal artery pulsatility index and renal volume. CONCLUSION: Increased fetal renal artery pulsatility index in intrauterine growth

  4. Does fetal macrosomia affect umbilical artery Doppler velocity waveforms in pregnancies complicated by gestational diabetes?

    Sirico, Angelo; Rizzo, Giuseppe; Maruotti, Giuseppe Maria; Aiello, Elisa; Morlando, Maddalena; Arduini, Domenico; Martinelli, Pasquale


    We aimed to establish whether macrosomic fetuses in pregnancies complicated by gestational diabetes (GDM) show different Pulsatility Index (PI) values in umbilical artery (UA) than in non-macrosomic fetuses. We considered 106 pregnant women with GDM. Doppler recordings of UA-PI were performed at 34-41 weeks and related to neonatal birthweight. Pregnancies were divided in two groups according to birthweight, macrosomic group (>4000 g) and controls (90th centile and 4000 g than in controls (PI = 0.69; 95% CI 0.64-0.74 versus PI = 0.87; 95% CI 0.84-0.90, p 90th centile than in controls (PI = 0.79; 95% CI 0.74-0.84 versus PI = 0.87; 95% CI 0.83-0.90; t = 2.653; p = 0.01). Linear regression analysis revealed a significant correlation between UA-PI and neonatal birthweight and between UA-PI and neonatal birthweight centile. Macrosomic fetuses of pregnancies complicated by GDM show lower values of UA-PI compared with controls. Despite UA-PI results, a variable related to macrosomia its role in the management of these pregnancies remains to be established.

  5. Polycystic Ovary Syndrome: The Correlation Between Renal Doppler Ultrasound and Laboratory Parameters

    Elif Karadeli


    Full Text Available Aim: To investigate whether there is alteration both right and left kidney lenght, parenchymal thickness, renal arterial,venous blood flow measurements in normotensive reproductive age women with polycystic ovary syndrome (PCOS. Material and Method: Forty women with PCOS according to Rotterdam criteria and thirty-six healthy volunteers women were included in our study. Hormonal, biochemical analysis, renal Doppler ultrasonography were performed and were investigated in terms of both left and right renal lenght, parenchymal thickness, peak systolic velocity (PSV, resistive index (RI, venous impedance index (VI, metabolic characteristics having insulin resistance, impaired glucose tolerance, serum lipid concentration. The student t test and pearson corelation test were used for statistical analysis.Results: The measurements for kidneys were not different between women with PCOS and healthy women. The peak systolic velocity of mean renal artery was lower in PCOS group. The mean renal venous impedance also was higher in PCOS group than control group. The mean renal resistive index was slightly higher in PCOS but not statistical significant. In bivariate corelation analyse including all patients, it was seen that BMI, WHR, level of serum fasting glucose, insulin, LDL, trigliserides were positively related with mean renal length and mean parenchymal thickness measurements. Discussion: We found that there was alterations kidney blood flow in normotensive reproductive age women with PCOS. This findings may indicate results of long term renal and cardiovascular complications of PCOS.

  6. Monitoring of renal hemodynamics during acute hemorrhagic shock with Doppler ultrasonic imaging: an experimental study

    Rui-hong LIU


    Full Text Available Objective To evaluate the value of color Doppler flow imaging (CDFI and pulsed-wave Doppler (PWD in monitoring renal hemodynamics in rabbits with acute hemorrhagic shock. Methods The experimental model of acute hemorrhagic shock was reproduced in 16 normal New Zealand white rabbits by controlled exsanguination which was divided into 4 different grades: normal (100% MAP, mild (70% MAP, moderate (50% MAP, and severe (40% MAP. The right kidney of the experimental animal was examined by gray-scale ultrasound (2DUS, CDFI and PWD. The structure of the right kidney was observed with 2DUS. CDFI was used to monitor the change in right renal hemodynamics along with the progression of shock. The hemodynamic parameters of main renal artery (MRA, segmental renal artery (SRA and interlobar renal artery (IRA were measured by PWD, including the peak systolic velocity (Vmax, minimum diastolic velocity (Vmin and resistive index (RI. Results The animal model of hemorrhagic shock was successfully reproduced in 16 healthy New Zealand rabbits, of which 14 rabbits survived at the end of the experiment, and 2 died of severe shock. The mean arterial pressure (MAP declined, while the respiratory rate and heart rate increased as the circulation changed from normal to severe shock (P<0.05. Observation of the right renal structure by 2DUS revealed no obvious changes after bleeding in different degrees. CDFI showed a gradually reduced distribution of blood flow in renal hemodynamics along with the progression of hemorrhagic shock. Vmax and Vmin declined gradually, while RI intensity increased as the hemorrhagic shock progressed from minor to severe. There was statistically significant difference in RI intensity between different grades of shock (P<005. Conclusion CDFI and PWD can quantitatively assess the renal hemodynamics during acute hemorrhagic shock, so it can be used as a noninvasive monitoring tool in the diagnosis and treatment of hemorrhagic shock. DOI: 10

  7. Renal venous thrombosis in an infant with predisposing thrombotic factors: color Doppler ultrasound and MR evaluation

    Argyropoulou, Maria I.; Papadopoulou, Frederica; Nikolopoulos, Pangiotis [Department of Radiology, Medical School, University of Ioannina, 45110, Ioannina (Greece); Giapros, Vassilios I.; Drougia, Aikaterini A.; Andronikou, Styliani [Neonatology Clinic, Medical School, University of Ioannina, 45110, Ioannina (Greece); Vartholomatos, Georgios A. [Department of Haematology, Medical School, University of Ioannina, 45110, Ioannina (Greece)


    We report a case of a neonate with hereditary thrombophilia presenting with renal venous thrombosis (RVT). Early color Doppler findings of RVT were lacking venous flow, and the arterial diastolic flow was reversed. This very high-resistance arterial flow is for the first time described in neonatal RVT. Magnetic resonance imaging showed low signal intensity of the renal pyramids on T1- and T2-weighted images, suggesting acute hemorrhage. After intravenous contrast injection, persistent cortical enhancement was observed along with lack of medullary enhancement. Despite the progressive reestablishment of some venous drainage, the kidney showed atrophy and loss of function. (orig.)

  8. Evaluation of the relationship between renal function and renal volume-vascular indices using 3D power Doppler ultrasound

    Cansu, Aysegul, E-mail:; Kupeli, Ali; Kul, Sibel; Eyuboglu, Ilker; Oguz, Sukru; Ozturk, Mehmet Halil; Dinc, Hasan


    Purpose: To investigate the relationship between renal function and total renal volume-vascular indices using 3D power Doppler ultrasound (3DPDUS). Materials and methods: One hundred six patients with hypertensive proteinuric nephropathy (HPN) (49 male, 57 female) and 65 healthy controls (32 male, 33 female) were evaluated prospectively using 3DPDUS. Total renal volume (RV), vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were calculated using Virtual Organ Computer-aided Analysis (VOCAL). The estimated glomerular filtration rates (GFRs) of the patients with HPN and the control group were calculated. The patients with HPN were divided into two groups on the basis of GFR, normal (≥90) or reduced (<90). Differences between groups were compared using ANOVA. Correlations between GFR, renal volume and vascular indices were analyzed using Pearson's correlation analysis. Significance was set at p < 0.05. Results: The mean total RV, VI, FI and VFI values in the reduced GFR, normal GFR and control groups were RV (ml): 234.7, 280.7 and 294.6; VI: 17.6, 27.6 and 46.8; FI: 79.1, 88.7 and 93.9 and VFI: 7.1, 12.7 and 23.8. There were statistically significant differences between the groups (p < 0.001). Total RVs and vascular indices exhibited significant correlations with estimated GFR (r = 0.53–0.59, p < 0.001) Conclusion: Three-dimensional power Doppler ultrasound is a reliable predictive technique in renal function analysis.

  9. Usefulness of resistive index on spectral Doppler ultrasonography in the detection of renal cell carcinoma in patients with end-stage renal disease

    Kim, Sang Youn; Woo, Sung Min; Cho, Jeong Yeon; Kim, Seung Hyup [Dept. of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of); Hwang, Sung Il; Lee, Hak Jong [Dept. of Radiology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); Moon, Min Hoan; Sung, Chang Kyu [Dept. of adiology, Seoul National University Boramae Hospital, Seoul (Korea, Republic of)


    The aim of this study was to explore the usefulness of the resistive index (RI) on spectral Doppler ultrasonography (US) in the detection of renal cell carcinoma (RCC) in patients with end-stage renal disease (ESRD). Seventeen ESRD patients with kidneys in which renal masses were suspected in routine US were subjected. They underwent computed tomography scans and additional Doppler US for the characterization of the detected lesions. All underwent radical nephrectomy with the suspicion of RCC. Fourteen patients finally were included. RI measurements were conducted in the region of the suspected renal mass and the background renal parenchyma. The intra class correlation coefficient was used to assess the reproducibility of the RI measurement. A paired t-test was used to compare the RI values between the renal mass and the background renal parenchyma (P<0.05). The RI values measured at the RCCs were significantly lower than those measured at the background renal parenchyma (0.41-0.65 vs. 0.75-0.89; P<0.001). The intrareader reproducibility proved to be excellent and good for the renal masses and the parenchyma, respectively (P<0.001). RI on spectral Doppler US is useful in detecting RCC in patients with ESRD. The RI values measured at the RCCs were significantly lower than those measured at the background renal parenchyma.

  10. Renal duplex doppler ultrasonography in patients with recurrent urinary tract infection

    Soliman Neveen


    Full Text Available Renal hemodynamics were studied using duplex Doppler ultrasonography in forty (33 females and 7 males; mean age: 12.1 ± 5.3 years normotensive patients with recurrent urinary tract infection and with no evidence of obstructive uropathy and age matched control group of 24 healthy children and adolescents. Resistivity index (RI and pulsatility index (PI in both arcuate (AA and interlobar (IA arteries were significantly higher in patients as compared to controls (P= 0.001, 0.01 respectively. Diastolic/systolic ratio (D/S at the same levels of renal vasculature (AA and IA was significantly lower in study patients as compared to their controls (P= 0.01, 0.001 respectively. Moreover, scarred renal units had higher RI and PI values as well as lower D/S ratio as compared to non scarred units (p= 0.01, 0.001, 0.001 respectively.. In conclusion, intra renal vascular resistivity is significantly increased in recurrent UTI patients particularly in those sus-taining renal scarring. Further follow up studies are recommended to determine if duplex assess-ment of intrarenal vasculature could be useful as an ancillary diagnostic and/or prognostic technique in the evaluation and follow up of recurrent UTI.

  11. Dupplex doppler sonography in patients with medical renal diseases: correlation with clinical and histopathologic findings

    Song, Soon Young; Koh, Byung Hee; Lee, Seung Chul; Bae, Jae Ik; Kim, Yong Soo; Rhim, Hyun Chul; Cho, On Koo; Park, Chan Hyun; Park, Moon Hyang [Hanyang Univ. College of Medicine, Seoul (Korea, Republic of)


    To compare the RI (resistive index) of renal artery with serum creatinine level and histological change in 50 patients with renal parenchymal disease. To measure RI in each patient, Doppler studies were performed three times in each kidney at the level of the interlobar arteries, and the average value of RI was taken. The study was performed 1 -3 days after renal biopsy and the time interval between blood sampling for serum creatinine and duplex study was also 1 - 3 days. The RI of patients with renal disease was also correlated with patient's age, sex and serum creatinine level, and RI was also correlated with the degree of severity of glomerular, interstitial, and vascular change in the kidneys. Statistical analysis was performed using Student's t test and Pearson's correlation method. The RI of the normal control and renal disease group was 0.566{+-}0.037 and 0.584{+-}0.038, respectively with no statistical significance(p=0.444). In the group with renal disease, there was no significant correlation between RI and a patient's age, sex, and serum creatinine level(p>0.05). RI was not significantly different between predominantly glomerular disease (n=45) and nonglomerular or mixed disease(n=5)(p=0.558), and did not correlate with the severity of glomerular sclerosis, interstitial fibrosis, or atherosclerosis(p>0.05). The authors conclude that RI is not helpful for the diagnosis and differential diagnosis of renal parenchymal diseases and does not correlate with serum creatinine levels. In order to define the role of the RI, further clinical experience with more cases is required.

  12. Doppler sonographic renal resistance index and resistance index ratio in children and adolescents with unilateral hydronephrosis

    Brkljacic, Boris [Department of Radiology, University Hospital ' ' Dubrava' ' , Av. G. Suska 6, 10000 Zagreb (Croatia); Kuzmic, Andrea Cvitkovic; Dmitrovic, Romana [Department of Pediatric Nephrology, Children' s Hospital, Klaiceva 16, 10000 Zagreb (Croatia); Rados, Marko [Department of Radiology, University Hospital Center, Kispaticeva 12, 10000 Zagreb (Croatia); Vidjak, Vinko [Department of Radiology, University Hospital ' ' Merkur' ' , Zajceva 19, 10000 Zagreb (Croatia)


    The aim of this study was to evaluate Doppler renal resistance index (RI) and RI ratio (RIR) in differentiating between obstructive and nonobstructive hydronephrosis in children and adolescents. The RI and RIR were measured in 32 healthy examinees (control group) and 29 patients with unilateral hydronephrosis. Ten patients had acute obstruction caused by a ureteric stone. Seven had obstructive hydronephrosis due to uretero-pelvic junction (UPJ) obstruction. Twelve patients had nonobstructive hydronephrosis. In controls the mean RI{+-}S.D. was 0.615{+-}0.04, and RIR 1.045{+-}0.033. In children with acute obstruction RI was 0.692{+-}0.035 and RIR 1.148{+-}0.037. In UPJ obstruction RI was 0.631{+-}0.054 and RIR 1.059{+-}0.047. In nonobstructive dilatation RI was 0.61{+-}0.038 and RIR 1.043{+-}0.042. The RI and RIR differences were statistically significant between controls and patients with acute colic (p<0.01), and between patients with acute obstruction and with nonobstructive hydronephrosis (p<0.01). In detecting acute obstruction RI{>=}0.70 was found to have a 70% sensitivity and a 92% specificity. The RIR{>=}1.10 was found optimal to distinguish obstructive from nonobstructive dilatation (sensitivity 90%, specificity 83%). Both RI and RIR are significantly elevated in patients with acute obstruction. Renal Doppler seems to be useful in children and adolescents for the detection of acute renal obstruction, although it cannot differentiate chronic obstruction due to the UPJ obstruction and nonobstructive renal collecting system dilatation. (orig.)

  13. Comparison of Ultrasound Corticomedullary Strain with Doppler Parameters in Assessment of Renal Allograft Interstitial Fibrosis/Tubular Atrophy.

    Gao, Jing; Rubin, Jonathan M; Weitzel, William; Lee, Jun; Dadhania, Darshana; Kapur, Sandip; Min, Robert


    To compare the capability of ultrasound strain and Doppler parameters in the assessment of renal allograft interstitial fibrosis/tubular atrophy (IF/TA), we prospectively measured ultrasound corticomedullary strain (strain) and intra-renal artery Doppler end-diastolic velocity (EDV), peak systolic velocity (PSV) and resistive index (RI) in 45 renal transplant recipients before their kidney biopsies. We used 2-D speckle tracking to estimate strain, the deformation ratio of renal cortex to medulla produced by external compression using the ultrasound transducer. We also measured Doppler EDV, PSV and RI at the renal allograft inter-lobar artery. Using the Banff scoring system for renal allograft IF/TA, 45 patients were divided into the following groups: group 1 with ≤5% (n = 12) cortical IF/TA; group 2 with 6%-25% (n = 12); group 3 with 26%-50% (n = 11); and group 4 with >50% (n = 10). We performed receiver operating characteristic curve analysis to test the accuracy of these ultrasound parameters and duration of transplantation in determining >26% cortical IF/TA. In our results, strain was statistically significant in all paired groups (all p 26%, including 26%-50% and >50%) and low-grade (≤25%, including 0.05). The areas under the receiver operating characteristic curve for strain, EDV, PSV, RI and duration of transplantation in determining >26% cortical IF/TA were 0.99, 0.94, 0.88, 0.52 and 0.92, respectively. Our results suggest that corticomedullary strain seems to be superior to Doppler parameters and duration of transplantation in assessment of renal allograft cortical IF/TA.

  14. Power doppler sonography in early renal transplantation: Does it differentiate acute graft rejection from acute tubular necrosis?

    Haytham M Shebel


    Full Text Available To evaluate the role of power Doppler in the identification and differentiation bet-ween acute renal transplant rejection and acute tubular necrosis (ATN, we studied 67 live donor renal transplant recipients. All patients were examined by spectral and power Doppler sono-graphy. Assessment of cortical perfusion (CP by power Doppler was subjective, using our grading score system: P0 (normal CP; homogenous cortical blush extending to the capsule, P1 (reduced CP; cortical vascular cut-off at interlobular level, P2 (markedly reduced CP; scattered cortical color flow at the interlobar level. Renal biopsies were performed during acute graft dysfunction. Pathological diagnoses were based on Banff classification 1997. The Mann- Whitney test was used to test the difference between CP grades with respect to serum creatinine (SCr, and resistive index (RI. For 38 episodes of acute graft rejection grade I, power Doppler showed that CP was P1 and RI ranging from 0.78 to 0.89. For 21 episodes of acute graft rejection grade II, power Doppler showed that CP was P1, with RI ranging from 0.88 to >1. Only one case of grade III rejection had a CP of P2. Twelve biopsies of ATN had CP of P0 and RI ranging from 0.80 to 0.89 There was a statistically significant correlation between CP grading and SCr (P <0.01 as well as between CP grading and RI (P <0.05. CP grading had a higher sensitivity in the detection of early acute rejection compared with RI and cross-sectional area measurements. We conclude that power Doppler is a non-invasive sensitive technique that may help in the detection and differentiation between acute renal transplant rejection and ATN, particularly in the early post-transplantation period.

  15. Doppler sonography in renal transplants; differential diagnosis of normal from acute rejection

    Lim, Gyeh Yon; Lee, M. H.; Son, K. M.; Shin, K. S.; Park, Y. H. [Seoul National University College of Medicine, Seoul (Korea, Republic of)


    We undertook a combined retrospective and prospective analysis of duplex Doppler examinations performed over a perion of 10 months in order to assess the value of Doppler study(DS)in evaluating renal allograft dysfunction. A total of 110 DS on 82 transplant patients were performed including 79 normal transplants, 29 acute rejections and 2 acute tubular necrosis(ATN). Resistive Index(RI) in 79 normal transplants ranged from 0.44 to 0.7 (Mean;0.59+0.07) in the arcuate artery, and from 0.45 to 0.75(mean;0.61+0.08) in the interlobar artery. RI in 29 cases of acute rejection ranged from 0.61 to 1.0 (mean; 0.77+0.10) in the interlobar artery. In ATNRI ranged from 0.59 to 0.63 (mean 0.62) in the arcuate artery, and from 0.59 to 0.62(mean 0.61) in the interlobar artery. The RI in acute rejection is significantly higher than that of the normal transplants (p<0.001). With a resistive index greater than 0.8, 100% positive predictive value was obtained for the diagnosis of acute rejection. The value less than 0.7 was unlikely to suggest acute rejection(negative predictive value 92%)

  16. MR angiography versus color Doppler sonography in the evaluation of renal vessels and the inferior vena cava in abdominal masses of pediatric patients.

    Pfluger, T; Czekalla, R; Hundt, C; Schubert, M; Graubner, U; Leinsinger, G; Scheck, R; Hahn, K


    Involvement of renal vessels and the inferior vena cava (IVC) plays a decisive role during operative planning for removal of abdominal masses in pediatric patients. Advantages and limitations of MR angiography and color Doppler sonography for determining these factors were evaluated. MR angiography and color Doppler sonography were performed preoperatively in 42 neonates, infants, and children with abdominal masses and were compared with spin-echo MR imaging and with surgical findings. Variables evaluated were anatomic variants, vessel displacement, patency of vessels, collateral circulation, and intravascular tumor extension. Quality of vessel visualization was assessed in vessels not affected by tumor. In 88% of unaffected renal vessels, the entire vessel course could be visualized on MR angiography compared with 58% on color Doppler sonography and 43% on spin-echo MR imaging. In four of nine cases, color Doppler sonography revealed an accessory renal artery, whereas MR angiography revealed these variants in seven of nine cases. MR angiography showed 79% and color Doppler sonography 66% of displaced vessels. Unlike MR angiography, color Doppler sonography did not reveal five stenotic renal veins because they could not be completely imaged. In two cases, however, MR angiography falsely indicated an occlusion of the IVC, whereas color Doppler sonography showed residual flow. Anatomic variants, vessel displacement, collateral circulation, and neoplastic vessel infiltration were revealed more accurately by MR angiography than by color Doppler sonography. In cases in which patency of the IVC is unclear on MR angiography, color Doppler sonography should also be performed.

  17. Comparative analysis of renal flow using contrast power Doppler and gray-scale ultrasound

    Sehgal, Chandra M.; Arger, Peter H.; Bovee, Kenneth C.; Pugh, Charles; Kirchhofer, Justin I.


    Our previous studies have shown that renal perfusion can be visualized by imaging the transit of a contrast agent through the parenchyma of the organ using gray scale (GS) and power Doppler (PD) ultrasound.However, the relative merits and the sensitivities of the two imaging methods are not known. This study compares the effectiveness of the two modes in visualizing kidney perfusion at the clinical dose of contrast agents. GS and PD images of the dog kidneys were recorded using a clinical ultrasound scanner at 4-7 MHz. A fixed longitudinal plane of the kidney was imaged by mounting the transducer on the animal with a specially designed holder. A dose of 0.1 m1/kg of Echogen was injected intravenously and GS and PD images were recorded simultaneously on two separate time-encoded video tapes during the passage of the contrast agent through the kidneys. The enhancement of GS and PD images was assessed qualitatively by three radiologists. The quantitative assessment was made by measuring the regional and global enhancements of digitized B-scan and PS images. Regional measurements were made by comparing brightness of the post contrast images with that of a pre-contrast reference image pixel by pixel. Student t-test was used to determine the statistical significance of the change. The regions representing statistically significant differences were encoded on the image in color with brightness proportional to the magnitude of change. The regions with no significant change were represented in GS. This generated a series of new images, referred to as StatMap, with color representing regions of perfusion. Changes in power Doppler images were visually detectable with high confidence in all five dogs by al three radiologists. There was no perceptible changes in B-scans. Computer analysis of PD images yielded characteristic indicator dilution curves in all five dogs with an initial rise time of 2-5 sec and a peak at 7-20 sec. The enhancement in PD lasted for 97-400 seconds. The

  18. Renal Doppler Resistive Index as a Marker of Oxygen Supply and Demand Mismatch in Postoperative Cardiac Surgery Patients

    Francesco Corradi


    Full Text Available Background and Objective. Renal Doppler resistive index (RDRI is a noninvasive index considered to reflect renal vascular perfusion. The aim of this study was to identify the independent hemodynamic determinants of RDRI in mechanically ventilated patients after cardiac surgery. Methods. RDRI was determined in 61 patients by color and pulse Doppler ultrasonography of the interlobar renal arteries. Intermittent thermodilution cardiac output measurements were obtained and blood samples taken from the tip of pulmonary artery catheter to measure hemodynamics and mixed venous oxygen saturation (SvO2. Results. By univariate analysis, RDRI was significantly correlated with SvO2, oxygen extraction ratio, left ventricular stroke work index, and cardiac index, but not heart rate, central venous pressure, mean artery pressure, pulmonary capillary wedge pressure, systemic vascular resistance index, oxygen delivery index, oxygen consumption index, arterial lactate concentration, and age. However, by multivariate analysis RDRI was significantly correlated with SvO2 only. Conclusions. The present data suggests that, in mechanically ventilated patients after cardiac surgery, RDRI increases proportionally to the decrease in SvO2, thus reflecting an early vascular response to tissue hypoxia.

  19. Renal Doppler Resistive Index as a Marker of Oxygen Supply and Demand Mismatch in Postoperative Cardiac Surgery Patients.

    Corradi, Francesco; Brusasco, Claudia; Paparo, Francesco; Manca, Tullio; Santori, Gregorio; Benassi, Filippo; Molardi, Alberto; Gallingani, Alan; Ramelli, Andrea; Gherli, Tiziano; Vezzani, Antonella


    Renal Doppler resistive index (RDRI) is a noninvasive index considered to reflect renal vascular perfusion. The aim of this study was to identify the independent hemodynamic determinants of RDRI in mechanically ventilated patients after cardiac surgery. RDRI was determined in 61 patients by color and pulse Doppler ultrasonography of the interlobar renal arteries. Intermittent thermodilution cardiac output measurements were obtained and blood samples taken from the tip of pulmonary artery catheter to measure hemodynamics and mixed venous oxygen saturation (SvO2). By univariate analysis, RDRI was significantly correlated with SvO2, oxygen extraction ratio, left ventricular stroke work index, and cardiac index, but not heart rate, central venous pressure, mean artery pressure, pulmonary capillary wedge pressure, systemic vascular resistance index, oxygen delivery index, oxygen consumption index, arterial lactate concentration, and age. However, by multivariate analysis RDRI was significantly correlated with SvO2 only. The present data suggests that, in mechanically ventilated patients after cardiac surgery, RDRI increases proportionally to the decrease in SvO2, thus reflecting an early vascular response to tissue hypoxia.

  20. Renal Doppler and Novel Biomarkers to Assess Acute Kidney Injury in a Swine Model of Ventricular Fibrillation Cardiac Arrest

    Xue Mei


    Full Text Available Background: Majority of the research on cardiac arrest (CA have focused on post-CA brain injury and myocardial dysfunction, the renal dysfunction and acute kidney injury (AKI in other critical illnesses after CA have not been well described. This study was designed to assess AKI with renal Doppler and novel AKI biomarkers in a swine model of ventricular fibrillation cardiac arrest (VFCA. Methods: Thirty healthy piglets were divided into VFCA group (n = 22 and Sham group (n = 8 in a blinded manner. Mean arterial pressure, heart rate, and cardiac output were recorded continuously. Cardiac arrest (CA was induced by programmed electric stimulation in the VFCA group, and then cardiopulmonary resuscitation was performed. Twenty piglets returned of spontaneous circulation (ROSC and received intensive care. Blood and urine samples were collected for AKI biomarkers testing, and Color Doppler flow imaging was performed at baseline, 6 h, 12 h, and 24 h, respectively after ROSC. At ROSC 24 h, the animals were sacrificed and a semi-quantitative evaluation of pathologic kidney injury was performed. Results: In the VFCA group, corrected resistive index (cRI increased from 0.47 ± 0.03 to 0.64 ± 0.06, and pulsatility index (PI decreased from 0.82 ± 0.03 to 0.68 ± 0.04 after ROSC. Cystatin C (CysC in both serum and urine samples increased at ROSC 6 h, but neutrophil gelatinase-associated lipocalin (NGAL in serum increased to 5.34 ± 1.68 ng/ml at ROSC 6 h, and then decreased to 3.16 ± 0.69 ng/ml at ROSC 24 h while CysC increasing constantly. According to the renal histopathology, 18 of 20 animals suffered from kidney injury. The grade of renal injury was highly correlated with RI, cRI, NGAL, and CysC. Linear regression equation was established: Grade of renal injury = 0.002 × serum CysC + 6.489 × PI + 4.544 × cRI - 8.358 (r2 = 0.698, F = 18.506, P < 0.001. Conclusions: AKI is common in post-CA syndrome. Renal Doppler and novel AKI biomarkers in serum and

  1. Renal Doppler and Novel Biomarkers to Assess Acute Kidney Injury in a Swine Model of Ventricular Fibrillation Cardiac Arrest

    Xue Mei; Chen-Chen Hang; Shuo Wang; Chun-Sheng Li; Ze-Xing Yu


    Background: Majority of the research on cardiac arrest (CA) have focused on post-CA brain injury and myocardial dysfunction, the renal dysfunction and acute kidney injury (AKI) in other critical illnesses after CA have not been well described.This study was designed to assess AKI with renal Doppler and novel AKI biomarkers in a swine model ofventricular fibrillation cardiac arrest (VFCA).Methods: Thirty healthy piglets were divided into VFCA group (n =22) and Sham group (n =8) in a blinded manner.Mean arterial pressure, heart rate, and cardiac output were recorded continuously.Cardiac arrest (CA) was induced by programmed electric stimulation in the VFCA group, and then cardiopulmonary resuscitation was performed.Twenty piglets retumed of spontaneous circulation (ROSC) and received intensive care.Blood and urine samples were collected for AKI biomarkers testing, and Color Doppler flow imaging was performed at baseline, 6 h, 12 h, and 24 h,respectively after ROSC.At ROSC 24 h, the animals were sacrificed and a semi-quantitative evaluation of pathologic kidney injury was performed.Results: In the VFCA group, corrected resistive index (cRI) increased from 0.47 ± 0.03 to 0.64 ± 0.06, and pulsatility index (PI) decreased from 0.82 ± 0.03 to 0.68 ± 0.04 after ROSC.Cystatin C (CysC) in both serum and urine samples increased at ROSC 6 h, but neutrophil gelatinase-associated lipocalin (NGAL) in serum increased to 5.34 ± 1.68 ng/ml at ROSC 6 h, and then decreased to 3.16 ± 0.69 ng/ml at ROSC 24 h while CysC increasing constantly.According to the renal histopathology, 18 of 20 animals suffered from kidney injury.The grade of renal injury was highly correlated with RI, cRI, NGAL, and CysC.Linear regression equation was established: Grade of renal injury =0.002 × serum CysC + 6.489 × PI + 4.544 × cRI-8.358 (r2 =0.698, F =18.506, P < 0.001).Conclusions: AKI is common in post-CA syndrome.Renal Doppler and novel AKI biomarkers in serum and urine are of significant

  2. Imaging features of gray-scale and contrast-enhanced color doppler US for the differentiation of transient renal arterial ischemia and arterial infarction

    Park, Byung Kwan; Kim Seung Hyup [Seoul National University Hospital, Seoul (Korea, Republic of); Moon, Min Hwan; Jung, Sung Il [Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)


    To characterize the imaging features on gray-scale and contrast-enhanced color Doppler US images which differentiate renal ischemia from renal infarction. The segmental renal arteries of eight healthy rabbits were surgically ligated. In four of these rabbits, the ligated renal artery was released 60 minutes after arterial occlusion to cause transient ischemia. In the remaining four rabbits, the arterial ligation was retained to cause a permanent infarction. The gray-scale and contrast-enhanced color Doppler US imaging features of the involved renal parenchymal of both ischemia and infarction groups were compared with respect to the presence or absence of parenchymal swelling, echogenicity changes, tissue loss and perfusion defects. Parenchyma swelling, echogenic changes, tissue loss and perfusion defects were found to be more extensive in the infarction than the ischemia group. The hyperechoic areas reperfused with blood flow recovered normal echogenicity and perfusion, whereas the hyperechoic areas without reperfusion became renal infarcts. Gray-scale and contrast-enhanced color Doppler US showed that the hyperechoic areas with reperfusion may reverse to normal parenchyma and allow the differentiation of renal ischemia from renal infarction.

  3. [Semi-invasive monitoring of cardiac output in renal transplantation by a new device using arterial pressure waveform analysis compare with intermittent pulmonary thermodilution].

    Terada, Takashi; Maemura, Yumi; Toyoda, Daisuke; Iwasaki, Ririko; Sato, Nobukazu; Ochtai, Ryoichi


    Clinical usefulness of PA catheter is controversial. We compared a new semi-invasive device (FloTrac/Vigileo) using arterial pressure waveform analysis for CO measurement in patients undergoing renal transplantation with bolus thermodilution method. Simultaneously CCO was measured, and we compared CCO with that obtained by bolus thermodilution method. Forty seven patients undergoing renal transplantation were enrolled. A PAC was inserted and radial arterial access was used for semi-invasive determination of CO (APCO) with the Vigileo. CO was measured simultaneously by bolus thermodilution and the Vigileo technique, and after starting operation, volume loading, before surgery, and other points were measured over 1 hour during measurements. And CCO was measured simultaneously at all points. Statistical analysis was performed using the method described by Bland and Altman. Bias was defined as the mean difference between the volumes obtained by pulmonary artery thermodilution and those by arterial pressure waveform analysis. Precision was expressed by the upper and lower limits of agreement. Means of age, height and weight were 45 years, 163.8 cm and 59.2 kg, respectively. Regression analysis of CO; APCO and ICO showed y = 0.8x + 2.2, R2 = 0.57. CCO and ICO; y = 0.8x + 1.1, R2 = 0.74. Average of APCO and ICO; bias = -0.65. SD = 1.54 average of CCO and ICO; bias = 0.38, SD = 1.23. In renal transplantation, CO measured by a new semi-invasive arterial pressure waveform analysis device showed good agreement with the volume obtained by intermittent pulmonary artery thermodilution method.

  4. An MSK Radar Waveform

    Quirk, Kevin J.; Srinivasan, Meera


    The minimum-shift-keying (MSK) radar waveform is formed by periodically extending a waveform that separately modulates the in-phase and quadrature- phase components of the carrier with offset pulse-shaped pseudo noise (PN) sequences. To generate this waveform, a pair of periodic PN sequences is each passed through a pulse-shaping filter with a half sinusoid impulse response. These shaped PN waveforms are then offset by half a chip time and are separately modulated on the in-phase and quadrature phase components of an RF carrier. This new radar waveform allows an increase in radar resolution without the need for additional spectrum. In addition, it provides self-interference suppression and configurable peak sidelobes. Compared strictly on the basis of the expressions for delay resolution, main-lobe bandwidth, effective Doppler bandwidth, and peak ambiguity sidelobe, it appears that bi-phase coded (BPC) outperforms the new MSK waveform. However, a radar waveform must meet certain constraints imposed by the transmission and reception of the modulation, as well as criteria dictated by the observation. In particular, the phase discontinuity of the BPC waveform presents a significant impediment to the achievement of finer resolutions in radar measurements a limitation that is overcome by using the continuous phase MSK waveform. The phase continuity, and the lower fractional out-of-band power of MSK, increases the allowable bandwidth compared with BPC, resulting in a factor of two increase in the range resolution of the radar. The MSK waveform also has been demonstrated to have an ambiguity sidelobe structure very similar to BPC, where the sidelobe levels can be decreased by increasing the length of the m-sequence used in its generation. This ability to set the peak sidelobe level is advantageous as it allows the system to be configured to a variety of targets, including those with a larger dynamic range. Other conventionally used waveforms that possess an even greater

  5. Periodic, pseudonoise waveforms for multifunction coherent ladar.

    Dierking, Matthew P; Duncan, Bradley D


    We report the use of periodic, pseudonoise waveforms in a multifunction coherent ladar system. We exploit the Doppler sensitivity of these waveforms, as well as agile processing, to enable diverse ladar functions, including high range resolution imaging, macro-Doppler imaging, synthetic aperture ladar, and range-resolved micro-Doppler imaging. We present analytic expressions and simulations demonstrating the utility of pseudonoise waveforms for each of the ladar modes. We also discuss a laboratory pseudonoise ladar system that was developed to demonstrate range compression and range-resolved micro-Doppler imaging, as well as the phase recovery common to each of the coherent modes.

  6. Computer simulations in comparison with in vivo measurements of nifedipine-induced changes in renal allograft hemodynamics.

    Merkus, J W; van Asten, W N; Hilbrands, L B; Hoitsma, A J; Koene, R A; Skotnicki, S H


    Analysis of Doppler spectrum waveforms is increasingly used in the differential diagnosis of human renal allograft dysfunction. The physiologic interpretation of changes in Doppler spectra obtained from renal allografts, however, remains a major problem. Computer simulation models of the renal circulation may provide insight into the physiologic mechanisms responsible for changes in Doppler spectrum characteristics. The results of measurements of renal allograft hemodynamics with both determinations of PAH clearance and Doppler spectrum analysis in 11 kidney allograft recipients were explained physiologically using a computer simulation model of kidney allograft hemodynamics. Using PAH clearance and blood pressure measurements a significant decrease in RVR was found (from 0.32 +/- 0.17 to 0.20 +/- 0.07 mm Hg x min/ml, P nifedipine. The Doppler spectrum waveform obtained from interlobar renal arteries showed a decrease in the RI (from 0.60 +/- 0.04 to 0.56 +/- 0.06; P < 0.05) and Tmax (from 133 +/- 32 to 98 +/- 32 ms; P < 0.05). The user-designed simulation model of renal hemodynamics showed comparable changes of the waveform when, in the model, the analogs of blood pressure, impedance of the artery, and the impedance of the peripheral vascular bed were altered proportionally.

  7. Doppler assessment of brachial artery flow as a measure of endothelial dysfunction in pediatric chronic renal failure.

    Hussein, Gehan; Bughdady, Yasser; Kandil, Manal E; Bazaraa, Hafez M; Taher, Heba


    Cardiovascular morbidity and mortality are highly prevalent among patients with chronic renal failure (CRF). Endothelial dysfunction is regarded as the initial reversible step in the development of atherosclerosis and has been demonstrated in all stages of renal failure. Non-invasive techniques to assess endothelial function have been recently developed and have been proven to predict future mortality in adults. We aimed to assess endothelial function in children with stage 4 chronic kidney disease (CKD 4) on conservative treatment, using a-non invasive, high-resolution, ultrasound Doppler study of the brachial artery flow, correlating it with other clinical and laboratory parameters. This study included 34 children with CKD 4 on conservative treatment who were compared with 30 healthy controls. Flow-mediated dilatation (FMD), nitroglycerin-mediated dilatation (NTG-MD) and FMD/NTG-MD ratio were estimated. FMD was abnormal (< 5%) in 24 patients (71%). FMD and FMD/NTG-MD ratio were significantly lower in patients than in controls (P = 0.001 and P = 0.01, respectively). FMD correlated positively with serum calcium and negatively with alkaline phosphatase. We concluded that endothelial dysfunction is present in children with CKD 4 on conservative treatment and may reflect increased atherogenic and thrombogenic properties of the endothelium, contributing to subsequent adverse cardiovascular outcome.

  8. SAR processing with non-linear FM chirp waveforms.

    Doerry, Armin Walter


    Nonlinear FM (NLFM) waveforms offer a radar matched filter output with inherently low range sidelobes. This yields a 1-2 dB advantage in Signal-to-Noise Ratio over the output of a Linear FM (LFM) waveform with equivalent sidelobe filtering. This report presents details of processing NLFM waveforms in both range and Doppler dimensions, with special emphasis on compensating intra-pulse Doppler, often cited as a weakness of NLFM waveforms.

  9. The contrast-enhanced Doppler ultrasound with perfluorocarbon exposed sonicated albumin does not improve the diagnosis of renal artery stenosis compared with angiography

    Bortolotto Luiz A


    Full Text Available Abstract There are no studies investigating the effect of the contrast infusion on the sensitivity and specificity of the main Doppler criteria of renal artery stenosis (RAS. Our aim was to evaluate the accuracy of these Doppler criteria prior to and following the intravenous administration of perfluorocarbon exposed sonicated albumin (PESDA in patients suspected of having RAS. Thirty consecutive hypertensive patients (13 males, mean age of 57 ± 10 years suspected of having RAS by clinical clues, were submitted to ultrasonography (US of renal arteries before and after enhancement using continuous infusion of PESDA. All patients underwent angiography, and haemodynamically significant RAS was considered when ≥50%. At angiography, it was detected RAS ≥50% in 18 patients, 5 with bilateral stenosis. After contrast, the examination time was slightly reduced by approximately 20%. In non-enhanced US the sensitivity was better when based on resistance index (82.9% while the specificity was better when based on renal aortic ratio (89.2%. The predictive positive value was stable for all indexes (74.0%–88.0% while negative predictive value was low (44%–51%. The specificity and positive predictive value based on renal aortic ratio increased after PESDA injection respectively, from 89 to 97.3% and from 88 to 95%. In hypertensives suspected to have RAS the sensitivity and specificity of Duplex US is dependent of the criterion evaluated. Enhancement with continuous infusion of PESDA improves only the specificity based on renal aortic ratio but do not modify the sensitivity of any index.

  10. Nursing of renal biopsy guided by Color Doppler ultrasound%彩超引导下肾穿刺活检的护理体会



    Objective To discuss the nursing strategies of renal biopsy guided by Color Doppler ultrasound. Methods Effective nursing was given to patients during preoperative, intraop-erative and postoperative stages. Results Sixty renal biopsy cases were done with 100% success rate and no serious complications occurred. Conclusion Effective preoperative, intraoperative and postoperative nursing intervention can decrease the incidence of complications of renal biopsy and it is the key to improve the success rate of renal biopsy.%目的 探讨对彩超引导下肾穿刺活检术患者的护理措施.方法 对患者进行术前、术中及术后的有效护理.结果60例患者肾穿刺活检术成功率为100%,无1例严重并发症发生.结论 有效的术前、术中及术后护理干预可以降低肾穿刺术后并发症的发生,是提高肾穿刺活检成功率的关键.

  11. Computer simulation studies of pulsed Doppler signals from vortices

    CHEN Sizhong; WANG Yuanyuan; WANG Weiqi


    A computer simulation method for pulsed Doppler signals from vortices was proposed to generate simulated vortex Doppler signals under various given circumstances. The relative waveforms, such as the maximum frequency waveform, the mean frequency waveform and the bandwidth waveform, were obtained using the short time Fourier analysis of those simulated signals. The relations were studied between several spectrum parameters obtained from these waveforms and given simulation conditions, such as the position and the size of the sample volume, the distance between two vortices, the free stream velocity and the maximum tangent velocity of the vortex. The sensitive parameters were found to detect vortices using the pulsed Doppler techniques.

  12. Goal-Directed Fluid Therapy Guided by Cardiac Monitoring During High-Risk Abdominal Surgery in Adult Patients: Cost-Effectiveness Analysis of Esophageal Doppler and Arterial Pulse Pressure Waveform Analysis.

    Legrand, Guillaume; Ruscio, Laura; Benhamou, Dan; Pelletier-Fleury, Nathalie


    Several minimally invasive techniques for cardiac output monitoring such as the esophageal Doppler (ED) and arterial pulse pressure waveform analysis (APPWA) have been shown to improve surgical outcomes compared with conventional clinical assessment (CCA). To evaluate the cost-effectiveness of these techniques in high-risk abdominal surgery from the perspective of the French public health insurance fund. An analytical decision model was constructed to compare the cost-effectiveness of ED, APPWA, and CCA. Effectiveness data were defined from meta-analyses of randomized clinical trials. The clinical end points were avoidance of hospital mortality and avoidance of major complications. Hospital costs were estimated by the cost of corresponding diagnosis-related groups. Both goal-directed therapy strategies evaluated were more effective and less costly than CCA. Perioperative mortality and the rate of major complications were reduced by the use of ED and APPWA. Cost reduction was mainly due to the decrease in the rate of major complications. APPWA was dominant compared with ED in 71.6% and 27.6% and dominated in 23.8% and 20.8% of the cases when the end point considered was "major complications avoided" and "death avoided," respectively. Regarding cost per death avoided, APPWA was more likely to be cost-effective than ED in a wide range of willingness to pay. Cardiac output monitoring during high-risk abdominal surgery is cost-effective and is associated with a reduced rate of hospital mortality and major complications, whatever the device used. The two devices evaluated had negligible costs compared with the observed reduction in hospital costs. Our comparative studies suggest a larger effect with APPWA that needs to be confirmed by further studies. Copyright © 2015 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  13. Designing waveforms for temporal encoding using a frequency sampling method

    Gran, Fredrik; Jensen, Jørgen Arendt


    , the amplitude spectrum of the transmitted waveform can be optimized, such that most of the energy is transmitted where the transducer has large amplification. To test the design method, a waveform was designed for a BK8804 linear array transducer. The resulting nonlinear frequency modulated waveform...... for the linear frequency modulated signal) were tested for both waveforms in simulation with respect to the Doppler frequency shift occurring when probing moving objects. It was concluded that the Doppler effect of moving targets does not significantly degrade the filtered output. Finally, in vivo measurements...


    LANDER, M; AARNOUDSE, JG; Oosterhof, H.

    Transition of fetal behavioural state IF to 2F coincides with cardiovascular changes measured by Doppler velocimetry e.g. a decrease in pulsatility index (PI) in the internal carotid arteries and in the descending aorta, indicating redistribution of blood flow. Recently, we reported a considerable

  15. Triplex Doppler da artéria renal e a relação entre a ecobiometria dos rins com distância atlanto-coccígea e altura em Canis familiaris Renal artery Triplex Doppler and the relationship between kidney ecobiometry with atlanto-coccyges distance (ACD and height (H in Canis familiaris

    Expedito Jr Matos Santana


    Full Text Available O objetivo do trabalho foi estabelecer a relação entre a ecobiometria renal com medidas de conformação corporal como a distância atlanto-coccígea (DAC e a altura (H de cães adultos saudáveis, obtendo-se parâmetros de normalidade para avaliar o tamanho e volume renal, bem como estabelecer valores de referência para avaliar a perfusão sanguínea dos rins por meio do índice de resistividade (IR e do índice de pulsatilidade (IP do ramo principal da artéria renal. No estudo foram utilizados 22 cães adultos sem raça definida, sendo 11 machos e 11 fêmeas. Os animais foram previamente aferidos quanto a DAC e a H. Os exames ultra-sonográficos foram realizados com um aparelho HDI 4000 PHILIPS munido de um transdutor microconvexo multifreqüêncial (5-8 MHz, dispositivos Doppler Colorido e Doppler de Fluxo. Os animais foram posicionados em decúbito lateral direito ou esquerdo, de acordo com o rim a ser avaliado. Os diâmetros longitudinal (DL e dorsoventral (DDV dos rins foram mensurados na secção longitudinal e, o diâmetro transversal (DT foi aferido no plano transversal. O volume (V foi calculado automaticamente pelo software do ultra-som. Com o uso do Triplex Doppler, o IR e o IP das artérias renais direita e esquerda foram obtidos. Todos os dados foram apresentados em média ± EPM. Análises de regressão linear foram realizadas tendo o DL, DDV, DT e V como variáveis dependentes e a DAC e H como variáveis independentes. Os IR e IP dos rins direito e esquerdo foram comparados pelo teste t de Student. A DAC variou de 54-78cm para machos e 37-71cm para fêmeas e a altura variou entre 34-64 cm para os machos e 24-57cm para as fêmeas. As médias obtidas para DL, DDV, DT e V dos rins esquerdo e direito foram: 5,24±0,27cm, 3,07±0,15cm, 3,07±0,9cm, 28,01±3,4mL e 4,50±0,19cm, 2,88±0,14cm, 2,71±0,15cm, 21,27±2,6mL, respectivamente. As análises de regressão linear entre as medidas lineares e volume renal com a DAC e a H foram

  16. Color-Doppler sonographic tissue perfusion measurements reveal significantly diminished renal cortical perfusion in kidneys with vesicoureteral reflux.

    Scholbach, T M; Sachse, C


    Vesicoureteral reflux (VUR) and its sequelae may lead to reduced renal perfusion and loss of renal function. Methods to describe and monitor tissue perfusion are needed. We investigated dynamic tissue perfusion measurement (DTPM) with the PixelFlux-software to measure microvascular changes in the renal cortex in 35 children with VUR and 28 healthy children. DTPM of defined horizontal slices of the renal cortex was carried out. A kidney was assigned to the "low grade reflux"-group if the reflux grade of the voiding cystourethrogram was 1 to 3 and to the "high grade reflux"-group if the reflux grade was 4 to 5. Kidneys with VUR showed a significantly reduced cortical perfusion. Compared to healthy kidneys, this decline reached in low and high grade refluxes within the proximal 50% of the cortex: 3% and 12 %, in the distal 50% of the cortex: 21% and 44 % and in the most distal 20 % of the cortex 41% and 44%. DTPM reveals a perfusion loss in kidneys depending on the degree of VUR, which is most pronounced in the peripheral cortex. Thus, DTPM offers the tool to evaluate microvascular perfusion, to help planning treatment decisions in children with VUR.

  17. 肾脏巨大错构瘤的超声诊断探讨%Discussion on the diagnosisudy of giant renal hamartoma with color Doppler ultrasound

    张清连; 张灌生; 钟跃


    Objective To discuss the value of color Doppler ultrasound on the diagnosis of giant (larger than 10cm) renal hamartoma (GRH). Methods Ultrasonic images of 9 cases with GRH confirmed by pathology after operation were retrospectively studied. Results 7 cases were diagnosed correctly by ultrasound (7/9), 1 case were mistaken as renal carcinoma (1/9) and 1 case was mistaken as adrenal gland fat tumor (1/9) in ultrasound diagnosis. The GRH shape was ellipse with clear margins. The GRH were showed high echo in 6 cases, middle echo in 2 cases and low echo in 1 case. That high alternate with low echoes were composed "stripe sign" were observed in all high echo and middle echo GRH, and there were a few bloodstream signal in these masses. The low echo GRH were not observed "stripe sign", and there were more bloodstream signal. That the protruding parts of GRH pressed the kidneys to form "press sign" were observed in all cases. The GRH with spontaneous rupture were observed cystic area in 2 cases. Both kidneys had many high echo small hamartoma sign in 6 cases. Conclusion The GRH has some features in ultrasonic images, color Doppler ultrasound has important diagnostic value for GRH, it could be considered as the first diagnostic method before operation.%目的 探讨彩色多普勒超声诊断肾脏巨大错构瘤(最大径线大于10cm)的临床应用价值.方法 回顾性分析经手术病理证实的9例肾脏巨大错构瘤的超声检查资料,并对其超声表现特征进行分析.结果 9例肾脏巨大错构瘤超声诊断正确7例(77.78%),1例误诊为肾癌(11.11%),1例误诊为肾上腺脂肪瘤(11.11%).肾脏巨大错构瘤的声像大致呈椭圆形,轮廓清晰,6例呈高回声,2例呈中等回声,1例呈低回声.高回声及中等回声肿块内皆观察到了高低回声相间的“条纹征”,且肿块内血流稀少.低回声肿块内未见“条纹征”,血流较多.9例肾脏巨大错构瘤皆观察到了肿瘤的外突部分对

  18. 彩色多普勒超声检测高血压病肾动脉血流动力学的临床研究%Color Doppler ultrasonography for detecting renal artery hemodynamics in hypertensive patients

    瞿茹莼; 赵菊芳; 张春侠; 吴英龙; 张俊玲


    目的:探讨彩色多普勒超声检测高血压肾动脉血流动力学的诊断意义。方法收集就诊于江苏省昆山市第六人民医院超声科的临床诊断为高血压的患者96例作为观察组,同时收集该院进行健康体检的患者98例作为对照组,对所有研究对象均采用彩色多普勒超声进行检测,对两组患者的肾脏长径、实质厚度、肾窦厚度、实质厚度/肾窦厚度的比值以及肾窦部的段动脉中段和皮髓交界处的叶间动脉段血流各项参数进行比较。结果观察组患者的肾脏长径、实质厚度、肾窦厚度、实质厚度/肾窦厚度比值均高于对照组(P<0.05),观察组患者肾窦部的段动脉中段的收缩期最大血流速度(Vmax)、舒张期最低血流速度(Vmin)、阻力指数(RI)值低于对照组(P<0.05),观察组对象的叶间动脉段的Vmax、Vmin、RI值低于对照组,差异具有统计学意义(P<0.05)。结论彩色多普勒超声可以检测高血压病肾动脉血流动力学各项参数,可反映继发性肾灌注的改变,为临床诊断高血压病的早期肾功能损害提供了重要依据。%Objective To investigate the diagnostic significance of color Doppler ultrasonography for detecting renal artery hemodynamics of hypertension.Methods The patients with hypertension were chosen as observation group (n=96) and the objects with physical examinations were chosen as control group (n=98) from the Department of Ultrasonography of Sixth People’s Hospital of Kunshan City in Jiangsu Province. All objects were given the detections of color Doppler ultrasonography, and some indexes including renal length, renal parenchymal thickness, thickness of renal sinus and ratio of parenchymal thickness to sinus thickness, and hemodynamic parameters of middle segment of sinus renal artery (SRA) and segment of interlobular renal artery (IRA) at cortex-medulla junction were compared in 2 groups.Results The

  19. Instrument-independent flux units for laser Doppler perfusion monitoring assessed in a multi-device study on the renal cortex

    Petoukhova, AL; Steenbergen, W; Morales, F; Graaff, R; de Jong, ED; Elstrodt, JM; de Mul, FFM; Rakhorst, G


    To investigate the feasibility of instrument-independent perfusion units for laser Doppler flowmetry, a comparison was performed of two commercial fiberoptic laser Doppler perfusion monitors measuring the same flux situation for two different types of probes. In vivo measurements were performed on t

  20. Normalisation of a severely abnormal ductus venosus Doppler flow velocity waveform in a growth-retarded fetus with absent end-diastolic flow in the umbilical artery and congenital anomalies.

    Müller, T; Rehn, M; Girschick, G; Kristen, P; Dietl, J


    Doppler recordings of fetal venous blood flow seem to be superior to arterial velocimetry and CTG concerning the prediction of fetal outcome and optimal time of delivery in pregnancies with fetal growth retardation and AREDV. An improvement of arterial Doppler flow velocities has been described. We report the reappearance of a normal end-diastolic flow velocity in a ductus venosus temporarily showing reversed end-diastolic flow in a growth-retarded fetus with congenital anomalies. This normalization was accompanied by an improvement of the CTG, a loss of umbilical vein pulsations, a reappearance of umbilical diastolic flow and a progressive return of cerebral and venous blood flow into the 'normal' range. Improvement of fetal condition may be the explanation for our observation.

  1. Simple Waveforms, Simply Described

    Baker, John G.


    Since the first Lazarus Project calculations, it has been frequently noted that binary black hole merger waveforms are 'simple.' In this talk we examine some of the simple features of coalescence and merger waveforms from a variety of binary configurations. We suggest an interpretation of the waveforms in terms of an implicit rotating source. This allows a coherent description, of both the inspiral waveforms, derivable from post-Newtonian(PN) calculations, and the numerically determined merger-ringdown. We focus particularly on similarities in the features of various Multipolar waveform components Generated by various systems. The late-time phase evolution of most L these waveform components are accurately described with a sinple analytic fit. We also discuss apparent relationships among phase and amplitude evolution. Taken together with PN information, the features we describe can provide an approximate analytic description full coalescence wavefoRms. complementary to other analytic waveforns approaches.

  2. The renal arterial resistive index and stage of chronic kidney disease in patients with renal allograft

    Winther, Stine O; Thiesson, Helle C; Poulsen, Lene N;


    The study investigated the optimal threshold value of renal arterial resistive index as assessed by Doppler ultrasonography determining chronic kidney disease stage 4 or higher in patients with renal allograft.......The study investigated the optimal threshold value of renal arterial resistive index as assessed by Doppler ultrasonography determining chronic kidney disease stage 4 or higher in patients with renal allograft....


    DIJKSTRA, K; AARNOUDSE, JG; Oosterhof, H.


    Pulsed-wave Doppler ultrasound was used to evaluate the influence of Braxton Hicks' contractions on flow velocity waveforms in the uterine arteries. Flow velocity waveforms were obtained from a standardized site, at the crossing of the uterine artery with the external iliac artery near the uterine w




    Full Text Available AIM : To detect abnormal waveforms in uterine artery in pregnancies at risk between 20 to 24 weeks of gestation and to measure Resistance index (RI and systolic/diastolic ratio(S/D of these waveforms in study population and to study correlation of Doppler dat a with adverse pregnancy outcome. METHODS : This is a prospective study included Doppler analysis of uterine artery waveforms in 107 normotensive women with singleton pregnancy between 20 to24 weeks of period of gestation who were considered to be at increa sed risk of developing pregnancy complications. Women with Multiple gestation, with congenital anomaly of fetus, chronic hypertension, renal disease, cardiac disease, Diabetes Mellitus were excluded from the study. Bilateral uterine artery Doppler was done and Parameters studied were S/D ratio and RI in uterine artery. Early diastolic notch in uterine artery was watched for. The flow velocity waveforms considered abnormal if there was an early diastolic notch in uterine artery in either right or left uterin e artery was watched for abnormal pregnancy outcomes considered are Gestational hypertension, Pre - eclampsia IUGR, Abruptio placentae, IUD and preterm deliveries. RESULTS : minimum women were aged 21 – 25 year with minimum of 18 years and maximum of 36 years, 28% were primigravidae while 72% were multigravidae mean gestational age of which scan was done was 22 wks 1 day (20 - 24 minimum gestational age at time of delivery was 28 wks of gestation 70% women were delivered vaginally and 30% LSCS. 7% women developed Gestational Hypertension, 5% developed Preeclampsia, 8% neonates with IUGR, 3% developed Placental Abruption while 4% had IUD and 8% had Preterm deliveries. CONCLUSION : Abnormal uterine artery Doppler studies in second trimester have been associated with subsequent adverse pregnancy out comes including Preeclampsia IUGR and perinatal mortality. Doppler velocimetry is a primary tool for fetomaternal surveillance in high

  5. The renal perfusion assessment by renal Doppler during fluid challenge in critical patients%重症患者溶液冲击治疗后肾脏抵抗指数的变化

    邓超; 李英; 苏醒; 曹玉芳; 陈栩栩


    Objective To assess renal resistive index variations in response to fluid challenge. Methods This is prospective cohort study, 30 patients with consecutive patients receiving mechanical ventilation and requiring a fluid challenge, which was measured resistive index before and after fluid challenge. Renal Doppler was used to measure resistive index and esophageal Doppler to monitor aortic blood flow. Results Of the 35 included patients, 17 (49%) met our definition for fluid challenge responsiveness, that is, had at least a 10% increase in aortic blood flow. After fluid challenge, mean arterial pressure increased from 73 mm Hg (interquartile range 68-79) to 80 mm Hg (75-86; P<0.0001) and stroke volume from 50 ml (30-77) to 55 ml (39-84; P<0.0001). Stroke volume changes after fluid challenge were +28.6% (+18.8% to+38.8%) in fluid challenge responders and +3.1%(-1.6%to 7.4%) in fluid challenge nonresponders. Renal resistive index was unchanged after fluid challenge in both nonresponders (0.72 [0.67-0.75] before and 0.71 [0.67-0.75] after fluid challenge;P=0.62) and responders (0.70 [0.65-0.75] before and 0.72 [0.68-0.74] after fluid challenge;P=0.11). Stroke volume showed no correlations with resistive index changes after fluid challenge in the overall population (r2=0.04, P=0.25), in fluid challenge responders (r2=-0.02, P=0.61), or in fluid challenge nonresponders (r2=0.08, P=0.27). Stroke volume did not correlate with resistive index changes after fluid challenge in the subgroups without acute kidney injury (AKIN definition), with transient acute kidney injury, or with persistent acute kidney injury. Conclusion Systemic hemodynamic changes induced by fluid challenge do not translate into resistive index variations in patients without acute kidney injury, with transient acute kidney injury, or with persistent acute kidney injury.%目的:初步探讨溶液冲击治疗后肾脏抵抗指数的变化。方法前瞻性队列研究,纳入35例需要连续机械通气

  6. Compressive sensing for high resolution profiles with enhanced Doppler performance

    Anitori, L.; Hoogeboom, P.; Chevalier, F. Le; Otten, M.P.G.


    In this paper we demonstrate how Compressive Sensing (CS) can be used in pulse-Doppler radars to improve the Doppler performance while preserving range resolution. We investigate here two types of stepped frequency waveforms, the coherent frequency bursts and successive frequency ramps, which can be

  7. 彩色多普勒超声监测生长迟缓胎儿脐动脉血液循环的变化%Color Doppler monitoring the blood flow velocity waveforms of the fetal umbilical artery of intrauterine growth retardation

    黄子健; 潘素慈; 戴常平; 李秋明


    目的 应用彩色多普勒超声监测生长迟缓(IUGR)胎儿的脐动脉血液循环。方法 测定130例妊娠20~42周妇女(其中正常49例、IUGR 81例)脐动脉时间平均血流速度(TAMX)、收缩期最大血流速度与舒张末期血流速度的比值(S/D)、搏动指数(PI)、阻力指数(RI)、收缩期最大血流速度(Vmax)与舒张末期血流速度(Vmin)。结果 正常孕妇随孕龄增长,胎盘功能增强,胎儿血液循环日渐丰富。IUGR者则明显障碍,在20周时脐动脉TAMX显著下降,在30周后S/D、 PI及RI显著升高,Vmin显著下降,在35周时Vmax显著下降。出现舒张期血流停止或倒流。结论 彩色多普勒超声可直接测定脐动脉血液循环,能在早期诊断IUGR、判断病情及估计预后。%Objective To study the changes of the fetal circulation in intrauterine growth retardation (IUGR) cases.Methods Color Doppler ultrasound was used to detect blood flow velocity waveforms of the umbilical artery (UmA)in 130 pregnant women at 20~42 weeks′ gestation,of which 49 cases were normal pregnancy and 81 cases were IUGR.The indices included time average maximum (TAMX) ,pulsatility index (PI) , resistance index (RI) ,systolic maximum velocity (Vmax) /diastolic minimum velocity (Vmin) ratio (S/D).Results The results showed that the fetal circulation became abundant gradually with increasing gestational age in normal pregnancy group,but that TAMX was markedly decreased at 20 weeks′ gestation,S/D ratio,PI and RI were markedly elevated,Vmin was markedly decreased at 30 weeks′ gestation,and Vmax was markedly decreased at 35 weeks′ gestation in IUGR group.Conclusions Examining blood flow velocity waveforms of UmA by Color Doppler ultrasound was one of the best method to early diagnose and predict the prognosis of IUGR.

  8. Diabetic Nephropathy : Evaluation with Doppler Ultrasonography

    Sim, Jung Suk; Kim, Seung Hyup; Kang, Heung Sik; Park, Jae Hyung; Han, Man Chung [Seoul National University College of Medicine, Seoul (Korea, Republic of)


    To compare Doppler ultrasonography with laboratory tests in evaluation of diabetic nephropathy. Fifty-five patients (mean age = 60, M : F = 26 : 29) with diabetes mellitus underwent renal Doppler ultrasonography. Resistive indices were compared with degree of proteinuria, serum creatinine level, and creatinine clearance rate. Eighteen patients who showed no proteinuria or microscopic proteinuria had a mean resistive index (RI) of 0.72 (SD, 0.05), 16 patients with macroscopic proteinuria without nephrotic syndrome had a mean RI of 0.82 (SD, 0.13), and 21 patients with nephrotic syndrome had a mean RI of 0.90 (SD, 0.12). Renal RI correlated highly with serum creatinine level (r = 0.62) and creatinine clearance rate (r = -0.43). Renal Doppler ultrasonography provides a useful indication of renal function in diabetic nephropathy but cannot offer an advantage over conventional laboratory test

  9. Doppler Tomography

    Marsh, T R


    I review the method of Doppler tomography which translates binary-star line profiles taken at a series of orbital phases into a distribution of emission over the binary. I begin with a discussion of the basic principles behind Doppler tomography, including a comparison of the relative merits of maximum entropy regularisation versus filtered back-projection for implementing the inversion. Following this I discuss the issue of noise in Doppler images and possible methods for coping with it. Then I move on to look at the results of Doppler Tomography applied to cataclysmic variable stars. Outstanding successes to date are the discovery of two-arm spiral shocks in cataclysmic variable accretion discs and the probing of the stream/magnetospheric interaction in magnetic cataclysmic variable stars. Doppler tomography has also told us much about the stream/disc interaction in non-magnetic systems and the irradiation of the secondary star in all systems. The latter indirectly reveals such effects as shadowing by the a...

  10. Valuation of color Doppler ultrasound in monitoring hemodynamic parameters following renal transplantation%彩色多普勒超声在肾移植后监测中的应用



    背景:超声检查已经成为了肾移植后的常规检查及监测方法.目的:探讨彩色多普勒超声在肾移植后监测的应用价值.方法:对61 例同种异体肾移植后患者采用彩色多普勒超声进行检测,其中移植肾正常组35 例,急性排斥反应组22 例,慢性排斥反应组4 例.对所有患者进行常规超声探查,结合彩色多普勒及能量多普勒观察移植肾的观察移植肾结构、血流灌注情况,测量各级血管的血流参数.结果与结论:急性排斥反应组移植肾较功能正常组明显肿大,彩色多普勒显像、多普勒能量图显示肾实质血流信号减少,舒张期明显,各级动脉阻力指数和搏动指数明显增高;慢性排斥反应组移植肾体积较功能正常组明显减小,彩色多普勒显像、多普勒能量图显示肾动脉内径明显缩小,动脉阻力指数和搏动指数明显升高.提示,应用超声能早期无创的观察移植肾的血流灌注情况,测量移植肾各级血管的血流参数能敏感的反应移植肾的功能状况.%BACKGROUND: Ultrasound examination has been a routine examination and monitoring method following renal transplantation.OBJECTIVE: To investigate the value of color Doppler ultrasound in monitoring hemodynamic parameters of the transplanted kidney.METHODS: Sixty-one patients of allograft renal transplantation were divided into 3 groups of which 35 patients in normal group,22 in acute rejection group, and 4 in chronic rejection group. Conventional ultrasound examination combined with color Doppler flow image (CDFI) and power Doppler image (PDI) was performed with each objects to observe construction, blood perfusion and measure the hemodynamic parameters of various vessels in transplanted kidney.RESULTS AND CONCLUSION: Swelling, renal parenchyma thickening and echo enhancement were demonstrated in acute rejection group. The bound between cortex and medullary substance was blurring. CDFI and PDI indicated that the blood

  11. 彩色多普勒超声评估微创经皮肾镜取石术对肾血流灌注的影响%Color doppler ultrasound assessment of minimally invasive percutaneous nephrolithotomy on renal perfusion

    吴晓翔; 刘秀平; 张凤玲; 朱萍


    目的:使用彩色多普勒超声评估微创经皮肾镜取石术对肾血流灌注的影响。方法:选择行微创经皮肾镜取石术的62例患者为研究对象,观察其肾动脉血流彩色多普勒超声表现,分析和比较手术前后收缩期峰值流速(PSV)、舒张末期流速(EDV)及阻力指数(RI)等参数的变化情况。结果:与术前相比,术后肾叶间动脉、段动脉PSV、EDV明显较高,差异有统计学意义(P<0.05),术后RI比较差异无统计学意义(P>0.05);术后肾主动脉远心端PSV、EDV与术前比较差异无统计学意义(P>0.05),RI明显低于术前,差异有统计学意义(P<0.05),肾主动脉近心端PSV、EDV、RI与术前比较差异无统计学意义(P>0.05)。结论:微创经皮肾镜取石术能明显改善肾内血流灌注,彩色多普勒超声是评估其改善情况的敏感指标,在制定治疗方案、评估疗效等方面具有重要的临床意义。%Objective Using color doppler ultrasound assessment of minimally invasive percutaneous nephrolithotomy on renal perfusion. Methods 62 cases of percutaneous nephrolithotomy minimally invasive patients as the research object,observethe renal artery hemodynamics with color Doppler ultrasonography before and after operation,the analysis and comparison of the peak systolic velocity(PSV),end diastolic velocity(EDV) and resistance index(RI) changes in parameters such as.Results Compared with the preoperative,postoperative renal leaf and segmental artery between PSV and EDV significantly higher,statistically significant difference(P0.05);Postoperative renal aorta telecentric side PSV,EDV compared with preoperative no significant difference(P>0.05),and RI were significantly lower than the preoperative,statistically significant difference(P0.05).Conclusion Minimally invasive percutaneous nephrolithotomy can significantly improve renal blood perfusion,color doppler ultrasound is sensitive

  12. Optical Doppler tomography and spectral Doppler imaging of localized ischemic stroke in a mouse model

    Yu, Lingfeng; Nguyen, Elaine; Liu, Gangjun; Rao, Bin; Choi, Bernard; Chen, Zhongping


    We present a combined optical Doppler tomography/spectral Doppler imaging modality to quantitatively evaluate the dynamic blood circulation and the artery blockage before and after a localized ischemic stroke in a mouse model. Optical Doppler Tomography (ODT) combines the Doppler principle with optical coherence tomography for noninvasive localization and measurement of particle flow velocity in highly scattering media with micrometer scale spatial resolution. Spectral Doppler imaging (SDI) provides complementary temporal flow information to the spatially distributed flow information of Doppler imaging. Fast, repeated, ODT scans across an entire vessel were performed to record flow dynamic information with high temporal resolution of cardiac cycles. Spectral Doppler analysis of continuous Doppler images demonstrates how the velocity components and longitudinally projected flow-volume-rate change over time for scatters within the imaging volume using spectral Doppler waveforms. Furthermore, vascular conditions can be quantified with various Doppler-angle-independent flow indices. Non-invasive in-vivo mice experiments were performed to evaluate microvascular blood circulation of a localized ischemic stroke mouse model.

  13. DSP Based Waveform Generator


    The DSP Based Waveform Generator is used for CSR Control system to control special controlled objects, such as the pulsed power supply for magnets, RF system, injection and extraction synchronization, global CSR synchronization etc. This intelligent controller based on 4800 MIPS DSP and 256M SDRAM technology will supply highly stable and highly accurate reference waveform used by the power supply of magnets. The specifications are as follows:

  14. Carotid arterial blood pressure waveform monitoring using a portable ultrasound system.

    Joohyun Seo; Pietrangelo, Sabino J; Hae-Seung Lee; Sodini, Charles G


    This work presents a non-invasive arterial blood pressure (ABP) waveform monitoring technique using ultrasound. A portable ultrasound system to excite ultrasound transducers and acquire data is designed with off-the-shelf components. The insonation angles are identified using a vector Doppler technique based on the cosine dependency of the Doppler signals. The pulse pressure of an estimated waveform at the left common carotid artery is compared to the standard sphygmomanometer measurement in a clinical test. The estimated carotid ABP waveform shows excellent agreement to the finger ABP waveform with expected discrepancy of the systolic peak shape due to different measurement sites. The proposed method also tracks slow blood pressure fluctuations. This validation on human subjects shows potential for a noninvasive blood pressure waveform monitoring device at central arterial sites.

  15. Arbitrary waveform generator

    Griffin, Maurice; Sugawara, Glen


    A system for storing an arbitrary waveform on nonvolatile random access memory (NVRAM) device and generating an analog signal using the NVRAM device is described. A central processing unit is used to synthesize an arbitrary waveform and create a digital representation of the waveform and transfer the digital representation to a microprocessor which, in turn, writes the digital data into an NVRAM device which has been mapped into a portion of the microprocessor address space. The NVRAM device is removed from address space and placed into an independent waveform generation unit. In the waveform generation unit, an address clock provides an address timing signal and a cycle clock provides a transmit signal. Both signals are applied to an address generator. When both signals are present, the address generator generates and transmits to the NVRAM device a new address for each cycle of the address timing signal. In response to each new address generated, the NVRAM devices provides a digital output which is applied to a digital to analog converter. The converter produces a continuous analog output which is smoothed by a filter to produce the arbitrary waveform.

  16. Arterial waveform analysis.

    Esper, Stephen A; Pinsky, Michael R


    The bedside measurement of continuous arterial pressure values from waveform analysis has been routinely available via indwelling arterial catheterization for >50 years. Invasive blood pressure monitoring has been utilized in critically ill patients, in both the operating room and critical care units, to facilitate rapid diagnoses of cardiovascular insufficiency and monitor response to treatments aimed at correcting abnormalities before the consequences of either hypo- or hypertension are seen. Minimally invasive techniques to estimate cardiac output (CO) have gained increased appeal. This has led to the increased interest in arterial waveform analysis to provide this important information, as it is measured continuously in many operating rooms and intensive care units. Arterial waveform analysis also allows for the calculation of many so-called derived parameters intrinsically created by this pulse pressure profile. These include estimates of left ventricular stroke volume (SV), CO, vascular resistance, and during positive-pressure breathing, SV variation, and pulse pressure variation. This article focuses on the principles of arterial waveform analysis and their determinants, components of the arterial system, and arterial pulse contour. It will also address the advantage of measuring real-time CO by the arterial waveform and the benefits to measuring SV variation. Arterial waveform analysis has gained a large interest in the overall assessment and management of the critically ill and those at a risk of hemodynamic deterioration.

  17. 超声对肝豆状核变性患者肾脏血流动力学变化的诊断价值%Detection of renal hemodynamics in patients with hepatolenticular degeneration by color Doppler ultrasound

    韦玉国; 胡文彬; 程楠; 许亚娟; 韩丽; 韩咏竹; 杨任民


    Objective To investigate the diagnostic value of color Doppler ultrasound for renal hemodynamic changes in hepatolenticular degeneration(HLD) patients. Methods Thirty healthy volunteers were served as control group, 61 patients with HLD were divided into HLD nephropathy group (group A) and HLD group with no changes in renal echo (group B) . Their master renal arteries (MRA),segmental renal arteries(SRA)and interlobular renal arteries(IRA)were detected by color Doppler ultrasound. The display rate of the arteries were calculated, the peak systolic velocity (PSV) and resistant index (RI)were measured. Results The display rate of MRA, SRA and IRA in control group and group B was 100%. The display rate of MRA, SRA and IRA in group A was 100%, 84.3% and 71.8%, respectively. Compared with control group, the PSV of MRA, SRA and IRA was decreased in group A and B, RI was increased. These differences had statistical significance (P < 0.05). Conclusion The renal hemodynamics has significant changes in HLD patients.%目的探讨彩色多普勒超声对肝豆状核变性(HLD)患者肾脏血流动力学改变的诊断价值。方法30例体检健康者为对照组,61例HLD患者分为肾脏回声改变组(A组)和肾脏回声无改变组(B组),彩色多普勒超声检测其三级肾动脉(肾主动脉、段间动脉、叶间动脉),计算三级动脉的显示率,测量收缩期最大血流速度和阻力指数。结果对照组和B组肾主动脉、段间动脉及叶间动脉显示率均为100%。A组肾主动脉显示率为100%,段间动脉显示率为84.3%,叶间动脉显示率为71.8%。与对照组比较,A组和B组的肾主动脉、肾段间动脉及叶间动脉血流速度减慢,阻力指数增高,差异均有统计学意义(P<0.05)。结论 HLD患者肾脏血管血流动力学状态可发生明显改变。

  18. Ultrasonographic study and Doppler flow velocimetry of maternal kidneys and liver in low-risk pregnancy

    Daher, Cibele Helena; Gomes, Andrea Cavalanti; Kobayashi, Sergio; Chammas, Maria Cristina, E-mail: [Universidade de Sao Paulo (In-Rad/HC-FMUSP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Inst. de Radiologia; Cerri, Giovanni Guido [Universidade de Sao Paulo (FMUSP), Sao Paulo, SP (Brazil). Fac. de Medicina


    Objective: longitudinal study with B-mode ultrasonography and Doppler ultrasonography of maternal kidneys and liver in low-risk pregnancy, to establish and quantify normality parameters, correlating them with physiological changes. Materials and methods: twenty-five pregnant women were assessed and selected to participate in the study, each of them undergoing four examinations at the first, second, third trimesters and postpartum. Results: findings during pregnancy were the following: increased renal volume, pyelocaliceal dilatation with incidence of 45.4% in the right kidney, and 9% in the left kidney; nephrolithiasis, 18.1% in the right kidney, 13.6% in the left kidney. With pyelocaliceal dilatation, mean values for resistivity index were: 0.68 for renal arteries; 0.66 for segmental arteries; 0.64 for interlobar arteries; 0.64 for arcuate arteries. Without pyelocaliceal dilatation, 0.67 for renal arteries; 0.64 for segmental arteries; 0.63 for interlobar arteries; and 0.61 for arcuate arteries. Portal vein flow velocities presented higher values in pregnancy, with mean value for maximum velocity of 28.9 cm/s, and 22.6 cm/s postpartum. The waveform pattern of the right hepatic vein presented changes persisting in the postpartum period in 31.8% of the patients. Cholelithiasis was observed in 18.1% of the patients. Conclusion: alterations in renal volume, pyelocaliceal dilatation, nephrolithiasis, cholelithiasis, changes in portal vein flow velocity, alterations in waveform pattern of the right hepatic vein, proved to be significant. (author)

  19. Ultrasonographic study and Doppler flow velocimetry of maternal kidneys and liver in low-risk pregnancy*

    Daher, Cibele Helena; Gomes, Andrea Cavalanti; Kobayashi, Sergio; Cerri, Giovanni Guido; Chammas, Maria Cristina


    Objective Longitudinal study with B-mode ultrasonography and Doppler ultrasonography of maternal kidneys and liver in low-risk pregnancy, to establish and quantify normality parameters, correlating them with physiological changes. Materials and Methods Twenty-five pregnant women were assessed and selected to participate in the study, each of them undergoing four examinations at the first, second, third trimesters and postpartum. Results Findings during pregnancy were the following: increased renal volume, pyelocaliceal dilatation with incidence of 45.4% in the right kidney, and 9% in the left kidney; nephrolithiasis, 18.1% in the right kidney, 13.6% in the left kidney. With pyelocaliceal dilatation, mean values for resistivity index were: 0.68 for renal arteries; 0.66 for segmental arteries; 0.64 for interlobar arteries; 0.64 for arcuate arteries. Without pyelocaliceal dilatation, 0.67 for renal arteries; 0.64 for segmental arteries; 0.63 for interlobar arteries; and 0.61 for arcuate arteries. Portal vein flow velocities presented higher values in pregnancy, with mean value for maximum velocity of 28.9 cm/s, and 22.6 cm/s postpartum. The waveform pattern of the right hepatic vein presented changes persisting in the postpartum period in 31.8% of the patients. Cholelithiasis was observed in 18.1% of the patients. Conclusion Alterations in renal volume, pyelocaliceal dilatation, nephrolithiasis, cholelithiasis, changes in portal vein flow velocity, alterations in waveform pattern of the right hepatic vein, proved to be significant. PMID:26185338

  20. Ultrasonographic study and Doppler flow velocimetry of maternal kidneys and liver in low-risk pregnancy

    Cibele Helena Daher


    Full Text Available Abstract Objective: Longitudinal study with B-mode ultrasonography and Doppler ultrasonography of maternal kidneys and liver in low-risk pregnancy, to establish and quantify normality parameters, correlating them with physiological changes. Materials and Methods: Twenty-five pregnant women were assessed and selected to participate in the study, each of them undergoing four examinations at the first, second, third trimesters and postpartum. Results: Findings during pregnancy were the following: increased renal volume, pyelocaliceal dilatation with incidence of 45.4% in the right kidney, and 9% in the left kidney; nephrolithiasis, 18.1% in the right kidney, 13.6% in the left kidney. With pyelocaliceal dilatation, mean values for resistivity index were: 0.68 for renal arteries; 0.66 for segmental arteries; 0.64 for interlobar arteries; 0.64 for arcuate arteries. Without pyelocaliceal dilatation, 0.67 for renal arteries; 0.64 for segmental arteries; 0.63 for interlobar arteries; and 0.61 for arcuate arteries. Portal vein flow velocities presented higher values in pregnancy, with mean value for maximum velocity of 28.9 cm/s, and 22.6 cm/s postpartum. The waveform pattern of the right hepatic vein presented changes persisting in the postpartum period in 31.8% of the patients. Cholelithiasis was observed in 18.1% of the patients. Conclusion: Alterations in renal volume, pyelocaliceal dilatation, nephrolithiasis, cholelithiasis, changes in portal vein flow velocity, alterations in waveform pattern of the right hepatic vein, proved to be significant.

  1. Doppler imaging

    Piskunov, N [Department of Physics and Astronomy, Uppsala University, Box 515, S-75120 Uppsala (Sweden)], E-mail:


    In this paper, I present a short review of the history and modern status of Doppler imaging techniques, highlighting their dependence on the knowledge of the fundamental stellar parameters, the quality of stellar atmospheric models and the accuracy of spectral synthesis.

  2. The morphological and semi-quantitative study of contrast-enhanced color Doppler energy in renal perfusion%造影增强能量图对肾灌注形态学及半定量实验研究

    周翔; 张青萍; 高兴成; 乐桂蓉


    Objective To evaluate the application value of the contrast-enhanced color Doppler energy (CDE) in renal perfuison.Methods The renal arteries of 5 rabbits were progressively stenosed at three level. The morphology characterizes and time-intensity curve were studied at every stenosis level after contrast injection as bolus through peripheral vein.Results The contrast-enhanced absence of the cortex outer layer was clearly displayed by the contrast-enhanced CDE. The contrast-enhanced absence represents the reassignment of the re-perfusion renal blood under the ischemia condition. The kidney is the good organ in time-intensity curve study and the parameters of the curve can effectively describe the renal perfusion.Conclusions Contrast-enhanced CDE is good way to valuate the renal perfusion function.%目的 探讨造影增强肾能量图对缺血性肾灌注形态学的评价价值及利用时间-强度曲线半定量分析肾灌注功能的应用价值。方法 对5只实验兔递进性钳夹肾动脉主干,对每一钳夹级别均进行造影实验,采集实验动态图像,分析图像形态特征,并依据时间序列对不同部位行时间-强度曲线半定量分析。结果 造影增强肾能量图可敏感反映缺血状态下皮质外层血流再灌注分配的规律。肾是进行时间-强度曲线半定量分析的良好脏器,时间-强度曲线的相关参数可有效反映肾血流灌注量的变化。结论 造影增强肾能量图是评价肾组织灌注功能的良好手段。

  3. Full Waveform Inversion Using Waveform Sensitivity Kernels

    Schumacher, Florian; Friederich, Wolfgang


    We present a full waveform inversion concept for applications ranging from seismological to enineering contexts, in which the steps of forward simulation, computation of sensitivity kernels, and the actual inversion are kept separate of each other. We derive waveform sensitivity kernels from Born scattering theory, which for unit material perturbations are identical to the Born integrand for the considered path between source and receiver. The evaluation of such a kernel requires the calculation of Green functions and their strains for single forces at the receiver position, as well as displacement fields and strains originating at the seismic source. We compute these quantities in the frequency domain using the 3D spectral element code SPECFEM3D (Tromp, Komatitsch and Liu, 2008) and the 1D semi-analytical code GEMINI (Friederich and Dalkolmo, 1995) in both, Cartesian and spherical framework. We developed and implemented the modularized software package ASKI (Analysis of Sensitivity and Kernel Inversion) to compute waveform sensitivity kernels from wavefields generated by any of the above methods (support for more methods is planned), where some examples will be shown. As the kernels can be computed independently from any data values, this approach allows to do a sensitivity and resolution analysis first without inverting any data. In the context of active seismic experiments, this property may be used to investigate optimal acquisition geometry and expectable resolution before actually collecting any data, assuming the background model is known sufficiently well. The actual inversion step then, can be repeated at relatively low costs with different (sub)sets of data, adding different smoothing conditions. Using the sensitivity kernels, we expect the waveform inversion to have better convergence properties compared with strategies that use gradients of a misfit function. Also the propagation of the forward wavefield and the backward propagation from the receiver

  4. [Color-Doppler semiology in transplanted kidney].

    Rivolta, R; Castagnone, D; Burdick, L; Mandelli, C; Mangiarotti, R


    Color-encoded duplex ultrasonography (CEDU) makes a more accurate technique in kidney graft monitoring by combining real-time US with pulsed Doppler studies of renal vasculature. It is a non-invasive and easy technique. Suitable to study the whole renal artery and vein, CEDU also allows the qualitative and quantitative assessment of the intrarenal vasculature and therefore the easy diagnosis of such vessel dysfunctions as arteriovenous fistulas following biopsy. Moreover, Doppler spectral analysis can be used to distinguish among different causes of renal allograft dysfunction--i.e. rejection, cyclosporine nephrotoxicity or acute tubular necrosis. The value of the resistive index for the differential diagnosis is discussed. CEDU allows a more reliable measurement of renal blood flow thanks to the more precise evaluation of renal artery diameter and mean flow velocity.

  5. Waveform patterns and peak reversed velocity in vertebral arteries predict severe subclavian artery stenosis and occlusion.

    Chen, Shun-Ping; Hu, Yuan-Ping


    This study investigated the value of analyzing spectral Doppler waveform patterns and measuring the peak reversed velocity (PRV) of the vertebral artery (VA) in predicting proximal severe subclavian artery (SA) stenosis and occlusion. Fifty-one patients with proximal SA stenosis were studied retrospectively. Based on the depth of the mid-systolic notch, the Doppler waveforms of the ipsilateral VA were divided into five subtypes (type I, n = 8; type II, n = 8; type III, n = 6; type IV, n = 13; and type V, n = 16). PRV was also measured. PRV receiver operating characteristic curves were constructed to obtain the best cutoff value for predicting severe SA stenosis or complete SA occlusion. The results indicated that both VA Doppler waveform and PRV were associated with the degree of SA stenosis (p waveform in the VA had similar accuracy in predicting SA occlusion (84.3%, 43/51). PRV was more accurate than VA waveforms in predicting severe SA stenosis (98%, 50/51 vs. 94.1%, 48/51). However, no significant differences between the two methods in predicting severe SA stenosis were observed (p = 0.84). Thus, with severe obstruction of the SA, typical Doppler waveform patterns of the VA could be observed. PRV is a helpful criterion in predicting severe stenosis and occlusion of the SA.

  6. "To-and-fro" waveform in the diagnosis of arterial pseudoaneurysms

    Mustafa; Z; Mahmoud; Mohammed; Al-Saadi; Abdulwahab; Abuderman; Khalid; S; Alzimami; Mohammed; Alkhorayef; Babikir; Almagli; Abdelmoneim; Sulieman


    Medical ultrasound imaging with Doppler plays an essential role in the diagnosis of vascular disease. This study intended to review the clinical use of "to-and-fro" waveform at duplex Doppler ultrasonography(DDU) in the diagnosis of pseudoaneurysms in the arterial vessels of upper and lower extremities, abdominal aorta, carotid and vertebral arteries as well as to review our personal experiences of "to-and-fro" waveform at DDU also. After receiving institutional review board approval, an inclusive literature review was carried out in order to review the scientific foundation of "toand-fro" waveform at DDU and its clinical use in the diagnosis of pseudoaneurysms in various arterial vessels. Articles published in the English language between 2000 and 2013 were evaluated in this review study. Pseudoaneurysms in arterial vessels of the upper and lower extremities, abdominal aorta, carotid and vertebral arteries characterized by an extraluminal pattern of blood flow, which shows variable echogenicity, interval complexity, and "to-and-fro" flow pattern on color Doppler ultrasonography. In these arterial vessels, Duplex ultrasonography can demonstrate the degree of clotting, pseudoaneurysm communication, the blood flow patterns and velocities. Spectral Doppler applied to pseudoaneurysms lumen revealed systolic and diastolic turbulent blood flow with traditional "toand-fro" waveform in the communicating channel. Accurate diagnosis of pseudoaneurysm by spectral Doppler is based on the documentation of the "to-andfro" waveform. The size of pseudoaneurysm determines the appropriate treatment approach as surgical or conservative.

  7. "To-and-fro" waveform in the diagnosis of arterial pseudoaneurysms.

    Mahmoud, Mustafa Z; Al-Saadi, Mohammed; Abuderman, Abdulwahab; Alzimami, Khalid S; Alkhorayef, Mohammed; Almagli, Babikir; Sulieman, Abdelmoneim


    Medical ultrasound imaging with Doppler plays an essential role in the diagnosis of vascular disease. This study intended to review the clinical use of "to-and-fro" waveform at duplex Doppler ultrasonography (DDU) in the diagnosis of pseudoaneurysms in the arterial vessels of upper and lower extremities, abdominal aorta, carotid and vertebral arteries as well as to review our personal experiences of "to-and-fro" waveform at DDU also. After receiving institutional review board approval, an inclusive literature review was carried out in order to review the scientific foundation of "to-and-fro" waveform at DDU and its clinical use in the diagnosis of pseudoaneurysms in various arterial vessels. Articles published in the English language between 2000 and 2013 were evaluated in this review study. Pseudoaneurysms in arterial vessels of the upper and lower extremities, abdominal aorta, carotid and vertebral arteries characterized by an extraluminal pattern of blood flow, which shows variable echogenicity, interval complexity, and "to-and-fro" flow pattern on color Doppler ultrasonography. In these arterial vessels, Duplex ultrasonography can demonstrate the degree of clotting, pseudoaneurysm communication, the blood flow patterns and velocities. Spectral Doppler applied to pseudoaneurysms lumen revealed systolic and diastolic turbulent blood flow with traditional "to-and-fro" waveform in the communicating channel. Accurate diagnosis of pseudoaneurysm by spectral Doppler is based on the documentation of the "to-and-fro" waveform. The size of pseudoaneurysm determines the appropriate treatment approach as surgical or conservative.

  8. A New Approach to Teaching Human Cardiovascular Physiology Using Doppler Ultrasound.

    Looker, T.


    Explains the principles of the Doppler ultrasound technique and reviews its potential applications to the teaching of cardiovascular physiology. Identifies the instrumentation needed for this technique; provides examples and illustrations of the waveforms from the ultrasound blood velocimeter. (ML)

  9. Compressive full waveform lidar

    Yang, Weiyi; Ke, Jun


    To avoid high bandwidth detector, fast speed A/D converter, and large size memory disk, a compressive full waveform LIDAR system, which uses a temporally modulated laser instead of a pulsed laser, is studied in this paper. Full waveform data from NEON (National Ecological Observatory Network) are used. Random binary patterns are used to modulate the source. To achieve 0.15 m ranging resolution, a 100 MSPS A/D converter is assumed to make measurements. SPIRAL algorithm with canonical basis is employed when Poisson noise is considered in the low illuminated condition.

  10. Channel Influence Mitigation in Pseudo-noise Waveform Design for Radar Applications

    J. S. Kulpa


    Full Text Available Noise Radar is a rapidly developing technology which uses noise or pseudo-noise waveforms as sounding signals to de- tect targets of interest. The advantages of such waveforms are no range nor velocity ambiguities, the possibility of using continuous waveform and low probability of intercept. However, the noise waveform correlation sidelobes are spread across the entire range–Doppler plane and their level is de- termined by the time-bandwidth product. Such sidelobes limit the detection capability in the multitarget environment. Several algorithms exist that decrease the sidelobe level and thus enhance dynamic range of the radar, but they are very susceptible to distortions in an analogue channel. In this paper the author presents a method to create low-sidelobe waveforms using a filtering algorithm designed for given channel, decreasing the analogue front-end impact on the final properties of the waveforms.

  11. Aortic Blood Flow Reversal Determines Renal Function: Potential Explanation for Renal Dysfunction Caused by Aortic Stiffening in Hypertension.

    Hashimoto, Junichiro; Ito, Sadayoshi


    Aortic stiffness determines the glomerular filtration rate (GFR) and predicts the progressive decline of the GFR. However, the underlying pathophysiological mechanism remains obscure. Recent evidence has shown a close link between aortic stiffness and the bidirectional (systolic forward and early diastolic reverse) flow characteristics. We hypothesized that the aortic stiffening-induced renal dysfunction is attributable to altered central flow dynamics. In 222 patients with hypertension, Doppler velocity waveforms were recorded at the proximal descending aorta to calculate the reverse/forward flow ratio. Tonometric waveforms were recorded to measure the carotid-femoral (aortic) and carotid-radial (peripheral) pulse wave velocities, to estimate the aortic pressure from the radial waveforms, and to compute the aortic characteristic impedance. In addition, renal hemodynamics was evaluated by duplex ultrasound. The estimated GFR was inversely correlated with the aortic pulse wave velocity, reverse/forward flow ratio, pulse pressure, and characteristic impedance, whereas it was not correlated with the peripheral pulse wave velocity or mean arterial pressure. The association between aortic pulse wave velocity and estimated GFR was independent of age, diabetes mellitus, hypercholesterolemia, and antihypertensive medication. However, further adjustment for the aortic reverse/forward flow ratio and pulse pressure substantially weakened this association, and instead, the reverse/forward flow ratio emerged as the strongest determinant of estimated GFR (P=0.001). A higher aortic reverse/forward flow ratio was also associated with lower intrarenal forward flow velocities. These results suggest that an increase in aortic flow reversal (ie, retrograde flow from the descending thoracic aorta toward the aortic arch), caused by aortic stiffening and impedance mismatch, reduces antegrade flow into the kidney and thereby deteriorates renal function. © 2015 American Heart Association

  12. Colour Doppler ultrasound of the penis

    Wilkins, C.J.; Sriprasad, S.; Sidhu, P.S. E-mail:


    Because it is a superficial structure, the penis is ideally suited to ultrasound imaging. A number of disease processes, including Peyronie's disease, penile fractures and penile tumours, are clearly visualized with ultrasound. An assessment of priapism can also be made using spectral Doppler waveform technology. Furthermore, dynamic assessment of cavernosal arterial changes after pharmaco-stimulation allows diagnosis of arterial and venogenic causes for impotence. This pictorial review illustrates the range of diseases encountered with ultrasound of the penis.

  13. Doppler sonography of diabetic feet: Quantitative analysis of blood flow volume

    Seo, Young Lan; Kim, Ho Chul; Choi, Chul Soon; Yoon, Dae Young; Han, Dae Hee; Moon, Jeung Hee; Bae, Sang Hoon [Hallym University College of Medicine, Seoul (Korea, Republic of)


    To analyze Doppler sonographic findings of diabetic feet by estimating the quantitative blood flow volume and by analyzing waveform on Doppler. Doppler sonography was performed in thirty four patients (10 diabetic patients with foot ulceration, 14 diabetic patients without ulceration and 10 normal patients as the normal control group) to measure the flow volume of the arteries of the lower extremities (posterior and anterior tibial arteries, and distal femoral artery. Analysis of doppler waveforms was also done to evaluate the nature of the changed blood flow volume of diabetic patients, and the waveforms were classified into triphasic, biphasic-1, biphasic-2 and monophasic patterns. Flow volume of arteries in diabetic patients with foot ulceration was increased witha statistical significance when compared to that of diabetes patients without foot ulceration of that of normal control group (P<0.05). Analysis of Doppler waveform revealed that the frequency of biphasic-2 pattern was significantly higher in diabetic patients than in normal control group(p<0.05). Doppler sonography in diabetic feet showed increased flow volume and biphasic Doppler waveform, and these findings suggest neuropathy rather than ischemic changes in diabetic feet.

  14. The clinical study of percutaneous renal biopsy by automatic gun under real time color doppler ultrasound guidance%彩色多普勒超声引导下经皮肾活检术的临床应用

    席春生; 李亚妹; 王谨涵; 关怀; 李芸; 高健; 刘冬梅; 张萌


    目的探讨彩色多普勒超声引导下斜角进针经皮肾穿刺活检术的安全性和成功率及其影响因素。方法回顾分析了兰州军区兰州总医院226例经临床诊断的慢性肾脏病患者在彩色多普勒超声引导下用美国BARD MAGNUM自动活检枪斜角进针行经皮肾穿刺活检术,对影响穿刺成功率的有关因素进行分析,并与普通超声引导下经皮肾活检术对比。结果穿刺成功222例,成功率为98.4%,有4例未取得足够病理诊断的肾组织标本,活检标本长度为(10.5±4.5)mm,获取肾小球数目为(16.7±6.3)个。本研究中所有病例均未发现严重并发症。肉眼血尿发生率为0.4%(1/226),肾周血肿发生率0.9%(2/226)。在获取肾小球数目和穿刺成功率与文献报道一致,而术后并发症方面,明显低于文献报道。结论彩色多普勒超声引导下斜角进针经皮肾活检术成功率高,并发症少,值得进一步观察和推广。%Objective To investigate the safety and efficacy of color doppler ultrasound-guided renal biopsy using an automated biopsy gun, analysis the related risk factor. Methods The retrospective analysis method were used. Two hundred twenty-six patients with proveded chronic kidney diseases admited Lanzhou General Hospital were performed renal biopsy using an automated BARD biopsy gun made in America. The successful rate and complications were analyzed, and compared with common ultrasound guidance. Results Adequate renal tissue for histologic diagnosis was obtained by BARD MAGNUM biopsy gun was 98.4% of the patients, the average length of renal tissue sample was(10.5±4.5) milimeter, the average number of glomeruli was(16.7±6.3), the rate of gross hematuria was 0.4%. The total of complication was 0.9%(2/226). Conclusion Ultrasound guided percutanous renal biopsy with BARD MAGNUM automated biopsy gun is a kind of safe and accurate method of performing renal biopsy for kidney disease.

  15. Doppler Properties of Polyphase Coded Pulse Compression Waveforms.


    phase structure. An example is shown in Fig. 12 for a PI code. Each code can be generated or compressed with the same standard FFT phase filter Fig. 13. The phase shifts used before and after the FFT phase filter depend on the particular code. One way to reduce the 4-dB cyclic variation of...could be achieved by the use of additional phase shifters and delay lines in the F, output ports of the FFT phase filter shown in Fig. 12. EXPANSION r r

  16. Quantum optical waveform conversion

    Kielpinski, D; Wiseman, HM


    Currently proposed architectures for long-distance quantum communication rely on networks of quantum processors connected by optical communications channels [1,2]. The key resource for such networks is the entanglement of matter-based quantum systems with quantum optical fields for information transmission. The optical interaction bandwidth of these material systems is a tiny fraction of that available for optical communication, and the temporal shape of the quantum optical output pulse is often poorly suited for long-distance transmission. Here we demonstrate that nonlinear mixing of a quantum light pulse with a spectrally tailored classical field can compress the quantum pulse by more than a factor of 100 and flexibly reshape its temporal waveform, while preserving all quantum properties, including entanglement. Waveform conversion can be used with heralded arrays of quantum light emitters to enable quantum communication at the full data rate of optical telecommunications.

  17. Value of Doppler flow waveform of dutcus venosus in early screening of fetal congenital heart defects%静脉导管多普勒血流检测诊断胎儿先天性心脏病的价值

    艾先梅; 陈晓园; 邓享雄; 杨洪伟; 陈莉莉


    Objective To investigate the clinical value of Doppler flow waveform of dutcus venosus in early screening of fetal congenital heart disease (CHD). Methods A total of 3 600 pregnant woman with single fetus of 11~14 weeks’gestation in our hospital from September 2010 to August 2014 received ductus venosus (DV) flow spec-trum and nuchal translucency (NT). Echocardiography was used to test all the fetuses with NT thickening and DV ab-normity, which was also applied to test the fetuses at 18~20 weeks' gestation and during the second trimester of preg-nancy, all the fetuses of 22~24 weeks' gestation with normal NT and DV, as well as the fetuses suspected of CHD. One week after birth, all the fetuses received echocardiography examination and those with abortion suffered autopsy. The data was collected and statistically analyzed. Results Compared with the fetuses with normal NT, the fetuses with NT thickening had significantly higher incidence of CHD (P<0.01), with the positive predictive value of 32.73%, the sensitivity of 53.73%, and the specificity of 98.87%. Compared with fetuses with normal DV, the fetuses with DV ab-normity had significantly higher incidence of CHD (P<0.01), with the positive predictive value of 25.81%, the sensi-tivity of 57.14%and the specificity of 96.74%. Compared with fetuses with normal DV and NT, the fetuses with abnor-mal DV and NT had significantly higher incidence of CHD (P<0.01), with the positive predictive value of 62.00%, the sensitivity of 46.27%, and the specificity of 99.84%. Conclusion Doppler flow waveform of dutcus venosus shows high specificity and sensitivity in the detection of CHD, which can make an effective prenatal diagnosis of CHD in clinical practice. It is worthy of clinical promotion.%目的:探讨静脉导管多普勒血流检测对诊断胎儿先天性心脏病的临床价值。方法对本院2010年9月至2014年8月接诊的3600例孕11~14周的单胎孕妇行静脉导管血流频谱(DV)及

  18. The doppler ultrasound. La ecografia Doppler

    Contreras Cecilia, E.; Lozano Setien, E.; Hernandez Montero, J.; Ganado Diaz, T.; Jorquera Moya, M.; Blasco Pascual, E. (Hospital Universitario San Carlos. Madrid (Spain))


    The discovery and development of Doppler ultrasound has had a great influence on Medical practice since it allows the noninvasive study of vascular pathology, both arterial and venous, as well as the flow patterns of the different parenchyma. This article deals with the principles, limitations and interpretation of the Doppler signal, as well as the different Doppler ultrasound systems routinely employed in Medicine.

  19. Waveform Synthesizer For Imaging And Ranging Applications

    DUDLEY, PETER A.; [et al


    Frequency dependent corrections are provided for quadrature imbalance. An operational procedure filters imbalance effects without prior calibration or equalization. Waveform generation can be adjusted/corrected in a synthetic aperture radar system (SAR), where a rolling phase shift is applied to the SAR's QDWS signal where it is demodulated in a receiver; unwanted energies, such as imbalance energy, are separated from a desired signal in Doppler; the separated energy is filtered from the receiver leaving the desired signal; and the separated energy in the receiver is measured to determine the degree of imbalance that is represented by it. Calibration methods can also be implemented into synthesis. The degree of quadrature imbalance can be used to determine calibration values that can then be provided as compensation for frequency dependent errors in components, such as the QDWS and SSB mixer, affecting quadrature signal quality.

  20. 彩色多普勒超声诊断肾细胞癌及其 TNM分期的临床研究%Clinical study of the color Doppler ultrasonic and TNM staging of renal cell carcinoma

    张毅; 袁梅; 刘薇; 王伟; 王正滨; 孙立江; 李玉军


    Objective To explore clinical value of the color Doppler ultrasonic(CDU)and TNM staging of renal cell carcinoma.Methods 265 cases of renal cell carcinoma(RCC)confirmed by surgical pathology were retro-spectively analyzed.According to the WHO 2004 pathological types of classification standards and the American Joint Committee on Cancer(AJCC)cancer staging manual/6th TNMstaging criteria.The analyzed application of a CDFI to TNMstaging of renal cell carcinoma,and surgical pathology results werecompared.Results 265 cases of RCC and right kidney in 136 cases,129 cases of left kidney;Diameter of 1.5 -12.8cm;Pathological diagnosis of renal clear cell carcinoma in 226 cases(85.28%),28 cases of papillary renal cell carcinoma(10.57%),renal too color cell car-cinoma in 5 cases(1.89%),4 cases of multilocular cystic renal cell carcinoma(1.51%),Bellini duct carcinoma in 2 cases(0.75%).Diagnosis results of CDU and pathological in 250 cases(94.34%),CDU misdiagnosis leakage 15 cases(5.66%).Within the kidney showed low echo or high echo,and mixed echo lumps,and invasive growth to the surrounding tissues or organs sign for it.CDU showed the various blood flow signals were given priority to with renal clear cell carcinoma;CDU and surgical pathology TNMstaging coincidence rate was 90.40%(226 /250),inclu-ding T1 N0 -1 M0 ,T2 N0 -1 M0 ,T3 N0 -2 M0 -1 and T4 N0 -2 M0 -1 of coincidence rate were 92.12%(152 /165),85.71%(36 /42),82.14%(23 /28)and 100.00%(15 /15).Conclusion CDU can be used as the preferred method of diag-nosis and evaluation of renal cell carcinoma,which can can provide valuable information for TNMstaging.%目的:探讨彩色多普勒超声(CDU)诊断肾细胞癌(RCC)及其 TNM分期的临床应用价值。方法回顾性分析经手术病理证实的265例 RCC 患者的临床资料。根据2004年 WHO 病理类型的分类和2003年美国癌症联合会(AJCC)《癌症分期手册(第六版)》肾癌分期标准,采用 CDU 对 RCC 进行 TNM分期,并

  1. Doppler indicates of uterine artery Doppler velocimetry by placental location

    Han, Sung Shik; Park, Yong Won; Cho, Jae Sung; Kwon, Hye Kyeung; Kim, Jae Wook [Yonsei University College of Medicine, Seoul (Korea, Republic of)


    Our purpose was to investigate the relation between the vascular resistance of uterine artery and placental location and to establish the reference value of Doppler index in uterine artery by placental location. Placental location and flow velocity waveforms of both uterine arteries in 7,016 pregnant women after 18 weeks gestation were examined using color Doppler ultrasonography. Placental location was classified as central and lateral placental and the uterine artery with lateral placental were divided into ipsilateral uterine artery (same side of the placental) and contralateral uterine artery (opposite side of the placenta). The uterine artery with central placental was classified as the central uterine artery. Systolic-Diastolic ratio (S/D ratio) of uterine arteries by gestational weeks were calculated and compared with the placental location and perinatal outcomes. In the lateral placental group, the S/D ratio of the contralateral uterine artery was higher than the ipsilateral one (mean=2.08+0.34 vs 1.89+0.34, p=0.0001). S/D ratio of the uterine artery decreased during second trimester and the ratio after 27 weeks was a tendency to have a constant values(ipsilateral: 1.85+ 0.34, central : 1.96+ 0.40, contralateral: 2.01+0.54). S/D ratio of the uterine artery was affected by placental location. So when we evaluate Doppler spectrum of uterine artery, placental location should be considered and we established the reference value of Doppler index of uterine artery by placental location.

  2. 利用彩色多普勒超声对终末期肾病患者人工动静脉内瘘血管的监测%Using Color Doppler sonography in end-stage renal disease surveillance of artificial blood vessel arteriovenous internal fistula

    顾星; 茅红卫; 季平; 张新源


    Objective: The use of Color Doppler sonography monitoring end-stage renal disease artificial vascular arteriove-nous fistula. Methods: 34 cases of Color Doppler sonography in patients with end-stage renal disease artificial arteriovenous fistula vessel diameter, flow velocity, resistance index(RI), blood flow. Results:34 cases of patients with end-stage renal dis-ease in 25 cases of fistula patency good, there are different situations complications in nine cases. Conclusion: Color Doppler sonography in end-stage renal disease artificial arteriovenous fistula of the indicators play an important role in monitoring , artificial arteriovenous fistula inside diameter 3-7 mm, flow rate at 350-800 mL/min can meet the normal amount of hemodialysis.%目的:利用彩色多普勒超声监测终末期肾病患者人工动静脉内瘘的血管。方法:应用彩色多普勒超声测定34例终末期肾病患者人工动静脉内瘘血管内径、血流速度、阻力指数(resistent index,RI)、血流量。结果:34例终末期肾病患者中25例内瘘通畅良好,9例出现不同情况的并发症。结论:彩色多普勒超声在终末期肾病患者人工动静脉内瘘的各项指标监测中起重要作用,人工动静脉内瘘口内径在3~7 mm,血流量在350~800 mL/min时,可满足正常血透量。

  3. Electronics via waveform analysis

    Craig, Edwin C


    The author believes that a good basic understanding of electronics can be achieved by detailed visual analyses of the actual voltage waveforms present in selected circuits. The voltage waveforms included in this text were photographed using a 35-rrun camera in an attempt to make the book more attractive. This book is intended for the use of students with a variety of backgrounds. For this reason considerable material has been placed in the Appendix for those students who find it useful. The Appendix includes many basic electricity and electronic concepts as well as mathematical derivations that are not vital to the understanding of the circuit being discussed in the text at that time. Also some derivations might be so long that, if included in the text, it could affect the concentration of the student on the circuit being studied. The author has tried to make the book comprehensive enough so that a student could use it as a self-study course, providing one has access to adequate laboratory equipment.

  4. Color doppler sonography in thickened gallbladder wall

    Han, Sang Suk; Choi, Seok Jin; Seo, Chang Hae; Eun, Choong Ki [Inje Univ. College of Medicine, Kimhae (Korea, Republic of)


    The thickening of the gallbladder wall is a valuable finding for the diagnosis of cholecystitis, but may be seen in non-cholecystic disease as well as in acute or chronic cholecystitis. The purpose of this study is to determine the value of color Doppler sonography in differentiating the causes of thickened gallbladder wall. Ninety eight patients with thickened gallbladder wall(more than 3mm) which was not due to gallbladder cancer were prospectively evaluated with color Doppler sonography. Sixty-six cases, confirmed by pathologic reports and clinical records, were analyzed for correlation between thickened gallbladder wall and color flow signal according to the underlying causes. Of the 66 patients, 28 cases were cholecystitis and 38 cases had non-cholecystic causes such as liver cirrhosis, ascites, hepatitis, pancreatitis, renal failure, and hypoalbuminemia. Of the 28 patients with cholecystitis(12 acute, 16 chronic), 23(82%) had color Doppler flow signals in the thickened gallbladder wall. Of the 38 patients with non-cholecystic causes, eight(21%) had color Doppler flow signals. There was a statistically significant difference of color Doppler flow signals between the cholecystitis and non-cholecystic groups(p=0.0001). No significant difference of color Doppler flow signals was found between cases of acute and chronic cholecystitis. Of the 23 patients with color Doppler flow signals in 28 cases of cholecystitis, 18(78.3%) showed a linear pattern and five(21.7%) showed a spotty pattern. Of the eight patients with color Doppler flow signals in the 38 non-cholecystic cases, four(50%) showed a linear pattern and four(50%) showed a spotty pattern. In cholecystitis, a linear color Doppler flow signal pattern is a much more frequent finding than a spotty pattern. Color Doppler sonography is a useful and adequate method for determining whether a thickened gallbladder wall is the result of cholecystitis or has non-cholecystic causes.

  5. Assessing Accuracy of Waveform Models against Numerical Relativity Waveforms

    Pürrer, Michael; LVC Collaboration


    We compare currently available phenomenological and effective-one-body inspiral-merger-ringdown models for gravitational waves (GW) emitted from coalescing black hole binaries against a set of numerical relativity waveforms from the SXS collaboration. Simplifications are used in the construction of some waveform models, such as restriction to spins aligned with the orbital angular momentum, no inclusion of higher harmonics in the GW radiation, no modeling of eccentricity and the use of effective parameters to describe spin precession. In contrast, NR waveforms provide us with a high fidelity representation of the ``true'' waveform modulo small numerical errors. To focus on systematics we inject NR waveforms into zero noise for early advanced LIGO detector sensitivity at a moderately optimistic signal-to-noise ratio. We discuss where in the parameter space the above modeling assumptions lead to noticeable biases in recovered parameters.

  6. Optimizing defibrillation waveforms for ICDs.

    Kroll, Mark W; Swerdlow, Charles D


    While no simple electrical descriptor provides a good measure of defibrillation efficacy, the waveform parameters that most directly influence defibrillation are voltage and duration. Voltage is a critical parameter for defibrillation because its spatial derivative defines the electrical field that interacts with the heart. Similarly, waveform duration is a critical parameter because the shock interacts with the heart for the duration of the waveform. Shock energy is the most often cited metric of shock strength and an ICD's capacity to defibrillate, but it is not a direct measure of shock effectiveness. Despite the physiological complexities of defibrillation, a simple approach in which the heart is modeled as passive resistor-capacitor (RC) network has proved useful for predicting efficient defibrillation waveforms. The model makes two assumptions: (1) The goal of both a monophasic shock and the first phase of a biphasic shock is to maximize the voltage change in the membrane at the end of the shock for a given stored energy. (2) The goal of the second phase of a biphasic shock is to discharge the membrane back to the zero potential, removing the charge deposited by the first phase. This model predicts that the optimal waveform rises in an exponential upward curve, but such an ascending waveform is difficult to generate efficiently. ICDs use electronically efficient capacitive-discharge waveforms, which require truncation for effective defibrillation. Even with optimal truncation, capacitive-discharge waveforms require more voltage and energy to achieve the same membrane voltage than do square waves and ascending waveforms. In ICDs, the value of the shock output capacitance is a key intermediary in establishing the relationship between stored energy-the key determinant of ICD size-and waveform voltage as a function of time, the key determinant of defibrillation efficacy. The RC model predicts that, for capacitive-discharge waveforms, stored energy is minimized

  7. Waveform analysis of sound

    Tohyama, Mikio


    What is this sound? What does that sound indicate? These are two questions frequently heard in daily conversation. Sound results from the vibrations of elastic media and in daily life provides informative signals of events happening in the surrounding environment. In interpreting auditory sensations, the human ear seems particularly good at extracting the signal signatures from sound waves. Although exploring auditory processing schemes may be beyond our capabilities, source signature analysis is a very attractive area in which signal-processing schemes can be developed using mathematical expressions. This book is inspired by such processing schemes and is oriented to signature analysis of waveforms. Most of the examples in the book are taken from data of sound and vibrations; however, the methods and theories are mostly formulated using mathematical expressions rather than by acoustical interpretation. This book might therefore be attractive and informative for scientists, engineers, researchers, and graduat...

  8. Pseudo waveform inversion

    Shin, Chang Soo; Park, Keun Pil [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of); Suh, Jung Hee; Hyun, Byung Koo; Shin, Sung Ryul [Seoul National University, Seoul (Korea, Republic of)


    The seismic reflection exploration technique which is one of the geophysical methods for oil exploration became effectively to image the subsurface structure with rapid development of computer. However, the imagining of subsurface based on the conventional data processing is almost impossible to obtain the information on physical properties of the subsurface such as velocity and density. Since seismic data are implicitly function of velocities of subsurface, it is necessary to develop the inversion method that can delineate the velocity structure using seismic topography and waveform inversion. As a tool to perform seismic inversion, seismic forward modeling program using ray tracing should be developed. In this study, we have developed the algorithm that calculate the travel time of the complex geologic structure using shooting ray tracing by subdividing the geologic model into blocky structure having the constant velocity. With the travel time calculation, the partial derivatives of travel time can be calculated efficiently without difficulties. Since the current ray tracing technique has a limitation to calculate the travel times for extremely complex geologic model, our aim in the future is to develop the powerful ray tracer using the finite element technique. After applying the pseudo waveform inversion to the seismic data of Korea offshore, we can obtain the subsurface velocity model and use the result in bring up the quality of the seismic data processing. If conventional seismic data processing and seismic interpretation are linked with this inversion technique, the high quality of seismic data processing can be expected to image the structure of the subsurface. Future research area is to develop the powerful ray tracer of ray tracing which can calculate the travel times for the extremely complex geologic model. (author). 39 refs., 32 figs., 2 tabs.

  9. Ultrassonografia modo B e Doppler na avaliação renal de cães após administração intravenosa de meio de contraste iodado: validação da técnica

    Cláudia Matsunaga Martín


    Full Text Available Resumo: Meios de contraste iodado podem promover efeitos hemodinâmicos relacionados à vasoconstrição intrarrenal prolongada e redução da perfusão, predispondo à hipóxia e isquemia medular. Alterações de resistência vascular renal podem representar os primeiros sinais de mudança funcional desse órgão. A técnica Doppler pulsado é considerada acessível, não invasiva e permite avaliar a dinâmica vascular dos rins, por meio da aferição dos índices de resistividade (IR e pulsatilidade (IP. Contudo, na espécie canina, a aquisição de traçados espectrais pode ser penosa devido às dificuldades de varredura e captação de sinal Doppler, sobretudo em relação ao rim direito, devido à sua localização dorsocranial na cavidade abdominal, o que prolonga substancialmente a realização do exame. O objetivo deste estudo é comprovar que a avaliação Doppler pulsado das artérias intrarrenais do rim esquerdo de cães representa a repercussão hemodinâmica renal da administração intravenosa de meios de contraste iodado não sendo necessária a realização do exame nos dois rins. Foram avaliados ambos os rins de seis cadelas adultas em quatro momentos distintos: antes da infusão intravenosa do contraste radiológico e após 1,5 horas, 24 horas e 48 horas, por meio da análise subjetiva da morfologia, ecogenicidade cortical e grau de perfusão renais e análise objetiva do comprimento, volume e resistência vascular intrarrenais (IR e IP. Os parâmetros avaliados ao modo B e Doppler dos rins direito e esquerdo não apresentaram diferenças estatisticamente significativas entre si em cada momento avaliado. Assim, constatou-se que o exame ultrassonográfico Doppler pulsado do rim esquerdo representou a repercussão hemodinâmica renal da aplicação intravenosa de meios de contraste iodado, desde que morfometria, morfologia, ecogenicidade cortical e perfusão de ambos os rins fossem consideradas semelhantes na abordagem

  10. Waveform Catalog, Extreme Mass Ratio Binary (Capture)

    National Aeronautics and Space Administration — Numerically-generated gravitational waveforms for circular inspiral into Kerr black holes. These waveforms were developed using Scott Hughes' black hole perturbation...

  11. The pulsatility index and the resistive index in renal arteries. Associations with long-term progression in chronic renal failure

    Petersen, L J; Petersen, J R; Talleruphuus, U


    The pulsatility index (PI) and the resistive index (RI) are used as pulsed-wave Doppler measurements of downstream renal artery resistance. PI and RI have been found to correlate with renal vascular resistance, filtration fraction and effective renal plasma flow in chronic renal failure. The aim...

  12. Doppler ultrasonography of the lower extremity arteries: anatomy and scanning guidelines

    Hwang, Ji Young [Dept. of Radiology, Ewha Womans University School of Medicine, Seoul (Korea, Republic of)


    Doppler ultrasonography of the lower extremity arteries is a valuable technique, although it is less frequently indicated for peripheral arterial disease than for deep vein thrombosis or varicose veins. Ultrasonography can diagnose stenosis through the direct visualization of plaques and through the analysis of the Doppler waveforms in stenotic and poststenotic arteries. To perform Doppler ultrasonography of the lower extremity arteries, the operator should be familiar with the arterial anatomy of the lower extremities, basic scanning techniques, and the parameters used in color and pulsed-wave Doppler ultrasonography.

  13. Multiples waveform inversion

    Zhang, D. L.


    To increase the illumination of the subsurface and to eliminate the dependency of FWI on the source wavelet, we propose multiples waveform inversion (MWI) that transforms each hydrophone into a virtual point source with a time history equal to that of the recorded data. These virtual sources are used to numerically generate downgoing wavefields that are correlated with the backprojected surface-related multiples to give the migration image. Since the recorded data are treated as the virtual sources, knowledge of the source wavelet is not required, and the subsurface illumination is greatly enhanced because the entire free surface acts as an extended source compared to the radiation pattern of a traditional point source. Numerical tests on the Marmousi2 model show that the convergence rate and the spatial resolution of MWI is, respectively, faster and more accurate then FWI. The potential pitfall with this method is that the multiples undergo more than one roundtrip to the surface, which increases attenuation and reduces spatial resolution. This can lead to less resolved tomograms compared to conventional FWI. The possible solution is to combine both FWI and MWI in inverting for the subsurface velocity distribution.

  14. Colocated MIMO Radar: Beamforming, Waveform design, and Target Parameter Estimation

    Jardak, Seifallah


    Thanks to its improved capabilities, the Multiple Input Multiple Output (MIMO) radar is attracting the attention of researchers and practitioners alike. Because it transmits orthogonal or partially correlated waveforms, this emerging technology outperformed the phased array radar by providing better parametric identifiability, achieving higher spatial resolution, and designing complex beampatterns. To avoid jamming and enhance the signal to noise ratio, it is often interesting to maximize the transmitted power in a given region of interest and minimize it elsewhere. This problem is known as the transmit beampattern design and is usually tackled as a two-step process: a transmit covariance matrix is firstly designed by minimizing a convex optimization problem, which is then used to generate practical waveforms. In this work, we propose simple novel methods to generate correlated waveforms using finite alphabet constant and non-constant-envelope symbols. To generate finite alphabet waveforms, the proposed method maps easily generated Gaussian random variables onto the phase-shift-keying, pulse-amplitude, and quadrature-amplitude modulation schemes. For such mapping, the probability density function of Gaussian random variables is divided into M regions, where M is the number of alphabets in the corresponding modulation scheme. By exploiting the mapping function, the relationship between the cross-correlation of Gaussian and finite alphabet symbols is derived. The second part of this thesis covers the topic of target parameter estimation. To determine the reflection coefficient, spatial location, and Doppler shift of a target, maximum likelihood estimation yields the best performance. However, it requires a two dimensional search problem. Therefore, its computational complexity is prohibitively high. So, we proposed a reduced complexity and optimum performance algorithm which allows the two dimensional fast Fourier transform to jointly estimate the spatial location

  15. Micro-Doppler processing for ultra-wideband radar data

    Smith, Graeme E.; Ahmad, Fauzia; Amin, Moeness G.


    In this paper, we describe an operational pulse Doppler radar imaging system for indoor target localization and classification, and show how a target's micro-Doppler signature (μDS) can be processed when ultra-wideband (UWB) waveforms are employed. Unlike narrowband radars where time-frequency signal representations can be applied to reveal the target time-Doppler frequency signatures, the UWB system permits joint range-time-frequency representation (JRTFR). JRTFR outputs the data in a 3D domain representing range, frequency, and time, allowing both the μDS and high range resolution (HRR) signatures to be observed. We delineate the relationship between the μDS and the HRR signature, showing how they would form a complimentary joint feature for classification. We use real-data to demonstrate the effectiveness of the UWB pulse-Doppler radar, combined with nonstationary signal analyses, in gaining valuable insights into human positioning and motions.

  16. Multiplexed sub-Doppler spectroscopy with an optical frequency comb

    Long, David A; Plusquellic, David F; Hodges, Joseph T


    An optical frequency comb generated with an electro-optic phase modulator and a chirped radiofrequency waveform is used to perform saturation and pump-probe spectroscopy on the $D_1$ and $D_2$ transitions of atomic potassium. With a comb tooth spacing of 200 kHz and an optical bandwidth of 2 GHz the hyperfine transitions can be simultaneously observed. Interferograms are recorded in as little as 5 $\\mu$s (a timescale corresponding to the inverse of the comb tooth spacing). Importantly, the sub-Doppler features can be measured as long as the laser carrier frequency lies within the Doppler profile, thus removing the need for slow scanning or a priori knowledge of the frequencies of the sub-Doppler features. Sub-Doppler optical frequency comb spectroscopy has the potential to dramatically reduce acquisition times and allow for rapid and accurate assignment of complex molecular and atomic spectra which are presently intractable.

  17. STRS Compliant FPGA Waveform Development

    Nappier, Jennifer; Downey, Joseph


    The Space Telecommunications Radio System (STRS) Architecture Standard describes a standard for NASA space software defined radios (SDRs). It provides a common framework that can be used to develop and operate a space SDR in a reconfigurable and reprogrammable manner. One goal of the STRS Architecture is to promote waveform reuse among multiple software defined radios. Many space domain waveforms are designed to run in the special signal processing (SSP) hardware. However, the STRS Architecture is currently incomplete in defining a standard for designing waveforms in the SSP hardware. Therefore, the STRS Architecture needs to be extended to encompass waveform development in the SSP hardware. A transmit waveform for space applications was developed to determine ways to extend the STRS Architecture to a field programmable gate array (FPGA). These extensions include a standard hardware abstraction layer for FPGAs and a standard interface between waveform functions running inside a FPGA. Current standards were researched and new standard interfaces were proposed. The implementation of the proposed standard interfaces on a laboratory breadboard SDR will be presented.

  18. Comparison of diagnostic value of duplex and color Doppler ultrasound in experimental acute renal failure in rabbits%二维超声、频谱及彩色多普勒超声在评价实验性兔急性肾衰竭中的价值比较

    黄晓玲; 高云华


    Objective To compare the diagnostic value of two-dimentional ultrasound, spectrum and color Doppler ultrasound in experimental acute renal failure(ARF)in rabbits.Methods 50%glycerin(12~15 ml/kg)were injected into the thigh muscle of the back leg of the rabbit to induce an animal model of ARF. Ultrasonic examination was performed on the day before(T0)and days 1,3…13 after the injection(T1,T3… T13).Renal size was evaluated by two-dimensional ultrasound.The hemodynamic changes of the kidney were quantitatively analysed by spectrum Doppler, while color Doppler flow imaging(CDFI)and color Doppler power imaging(CDPI)were used to qualitatively study the blood perfusion of the kidney during ARF. The renal imaging in CDFI and CDPI were classified three grades.Grade I, the blood perfusion of the kidney was normal and the flow singles could be seen at the site near to the renal capsule.Grade II, the blood perfusion of the kidney was slightly abnormal and the flow singles could be seen in the renal cortex but not near to the capsule. Grade Ⅲ, the blood perfusion was heavily abnormal and the flow singles could not be seen in the renal cortex.Results The changes of renal hemodynamics and renal size began at T3,peaked at T5 and T7,and returned to normal at T9. The renal imaging of all rabbits were grade I in CDPI and CDFI at T0.In CDFI, all were gradeⅢat T1~T9, at T11 and T13 most of them only returned to grade Ⅱ, no one returned to grade I.In CDPI, however, all were grade Ⅱ at T1 and T3,while only a few were grade Ⅲ at T5 and T7,and most have returned to grade Ⅰ at T9. Conclusions During the period of ARF, two-dimensional ultrasound is useful in showing the echo and measuring the depth of renal cortex.Spectrum Doppler is helpful in quantitatively analysing the renal hemodynamic hanges. CDPI is more sensitive than CDFI in showing the blood perfusion of the kidney%目的 比较二维超声、频谱及彩色多普勒超声在诊断

  19. Waveform synthesis for imaging and ranging applications

    Doerry, Armin W.; Dudley, Peter A.; Dubert, Dale F.; Tise, Bertice L.


    Frequency dependent corrections are provided for quadrature imbalance and Local Oscillator (LO) feed-through. An operational procedure filters imbalance and LO feed-through effects without prior calibration or equalization. Waveform generation can be adjusted/corrected in a synthetic aperture radar system (SAR), where a rolling phase shift is applied to the SAR's QDWS signal where it is demodulated in a receiver; unwanted energies, such as LO feed-through and/or imbalance energy, are separated from a desired signal in Doppler; the separated energy is filtered from the receiver leaving the desired signal; and the separated energy in the receiver is measured to determine the degree of imbalance that is represented by it. Calibration methods can also be implemented into synthesis. The degree of LO feed-through and imbalance can be used to determine calibration values that can then be provided as compensation for frequency dependent errors in components, such as the QDWS and SSB mixer, affecting quadrature signal quality.

  20. Signal waveform design to detect an underwater high-speed small target

    YANG Chonglin; YAO Lan


    The problem of sonar signal waveform design to detect a high-speed small target in an underwater environment is discussed. From theoretical analysis, time-frequency hop signal is regarded as the most suitable signal waveform in this application. To get precise target parameter estimation ability, the signal should have high range-Doppler resolution performance.The results of signal analysis show that hop signal with frequency serial coding as Costas array has sharp ambiguity characteristic, so it can be used in an active sonar system to detect a high speed small target. A scheme of frequency coding is also presented.

  1. The Quantitative Evaluation for Renal Blood Flow Perfusion of Primary Glomerular Diseases by 3-Dimension Powerful Doppler Ultrasonic%三维能量多普勒超声对原发性肾小球疾病肾血流灌注的定量评价

    罗欢; 张惠芳; 黄蓉; 霍咪; 陈协辉


    目的:通过三维能量多普勒超声定量分析肾内血流的灌注参数和肾功能测值的关系,来了解原发性肾小球疾病所致慢性肾病患者肾脏损害的程度.方法:根据美国肾脏疾病生存质量指导(K/DOQI)指南诊断及分期标准选择原发性肾小球疾病患者60例,与正常对照组30例进行比较,应用彩色多普勒超声观察肾脏的形态结构,显示肾内各分级动脉血流充盈情况,脉冲多普勒显示段动脉及叶间动脉的脉冲多普勒频谱,测量阻力指数(RI),应用三维能量多普勒超声,观察肾脏的血流灌注显像,并利用血流分析技术,计算血管指数(VI).将肾血流灌注参数与肾功能测值及肾穿刺活检病理结果进行对照.结果:原发性肾小球疾病组在血流灌注显像、各级动脉的阻力指数(RI)及血管指数(VI)与正常对照组比较,存在显著差异,并随着肾功能损害越严重,差异越显著.结论:三维能量多普勒超声对慢性肾病各期肾血流灌注观察,可以为原发性肾小球疾病的早期肾功能损伤评估提供客观依据.%Objective:The 3-Dimension Powerful Doppler Ultrasonic was adopted to analyze quantitatively the relationship between the perfusion indices of blood flow inside the kidney and the measured values of kidney function so as to know the degree of the kidney damage of chronic kidney disease (CKD) patients caused by primary renal glomerular diseases.Methods: 60 cases of primary renal glomerular diseases were involved in the study group according to the diagnosis and staging criteria of Kidney Disease Survival Quality Instruction made by NKF (K/DOQI) compared with 30 cases as the normal control group. The Colorful Doppler Ultrasonic was adopted to observe the morphology and structure of kidney and show the filling of blood flow in various branches of arteries. The pulse Doppler was adopted to show the pulse Doppler spectrum of the segmental and interlobal arteries of kidney. The

  2. Color Doppler Imaging in the Diagnosis and Follow-up of Carotid Cavernous Sinus Fistulas


    This report describes color doppler imaging (CDI) in theevaluation and follow-up of nine patients with carotid cavernous sinusfistulas.The orbits and carotid arteries were examined with CDI.In allcases,the diagnosis was confirmed by angiography.CDI clearlydemonstrated the dilated superior ophthalmic veins (SOVs) with retrogradeflow and low resistance arterial doppler waveform in all nine patients (10eyes).After the study of quantitative hemodynamics,we found that directcarotid cavernous sinus fistulas s...

  3. Differential doppler heterodyning technique

    Lading, Lars


    Measuring velocity without disturbing the moving object is possible by use of the laser doppler heterodyning technique. Theoretical considerations on the doppler shift show that the antenna property of the photodetector can solve an apparent conflict between two different ways of calculating...... the detected doppler frequency. It is found that the doppler frequency for this particular setup is independent of the direction of detection. Investigations of the signal-to-noise ratio (SNR) show that the maximum SNR-considering the optical setup-is obtained by measuring the frequency difference between two...

  4. Waveform-dependent absorbing metasurfaces

    Wakatsuchi, Hiroki; Rushton, Jeremiah J; Sievenpiper, Daniel F


    We present the first use of a waveform-dependent absorbing metasurface for high-power pulsed surface currents. The new type of nonlinear metasurface, composed of circuit elements including diodes, is capable of storing high power pulse energy to dissipate it between pulses, while allowing propagation of small signals. Interestingly, the absorbing performance varies for high power pulses but not for high power continuous waves (CWs), since the capacitors used are fully charged up. Thus, the waveform dependence enables us to distinguish various signal types (i.e. CW or pulse) even at the same frequency, which potentially creates new kinds of microwave technologies and applications.

  5. Evaluation of renal blood perfusion: analysis of time-density curve with contrast-enhanced color Doppler%肾脏血流灌注的评估:造影增强彩色多普勒时间-强度曲线分析

    柳建华; 何景光; 冉虹; 罗卓鹏; 查道刚; 刘伊丽


    背景:超声评价肾脏功能主要通过测量较粗大的肾脏各级动脉的血流参数或肾切面内动脉彩色血流面积所占的比例来推断,误差较大.目的:应用超声仪器随机配置的彩色多普勒时间-强度曲线软件评价肾脏血流灌注情况.设计:动物实验观察.单位:广州市第一人民医院功能检查科.材料:实验于1999-01/2000-04在广州军区广州总医院动物实验室完成,选择8只健康新西兰兔,雌雄各4只,体质量2.5~3.5 kg.观察肾脏16个.声学造影剂为全氟显,主要成分为声振白蛋白的微泡,微泡内有一定浓度的全氟丙烷气体.方法:兔外周静脉团注造影剂全氟显后用彩色多普勒能量图、彩色多普勒血流显像和彩色多普勒能量谐波成像连续采集肾脏彩色血流图像,随机配置软件显示时间-强度曲线.主要观察指标:造影增强肾脏血流灌注时间-强度曲线的形态.结果:进入结果分析8只家兔.肾脏血流造影增强的时间-强度曲线呈单峰状,上升支陡直,下降支平缓.调节时间轴上的感兴趣线可作定量分析,回放显示注射造影剂后对应某一时刻的造影增强的彩色多普勒图像.结论:造影增强彩色多普勒血流显像和彩色多普勒能量图的时间-强度曲线能有效的观察肾脏血流灌注特征,既可显示整个肾脏的血流灌注情况,也用于观察低血流灌注区域,发现病灶进一步绘制肾功能图.%BACKGROUND:By using ultrasound examination, renal function was conventionally assessed through measuring the blood flow parameters of large renal arteries in all levels and the rate of the color flow area in arter ies on the cross section of kidneys, in which method great errors have been induced.OBJECTIVE: This study was designed to assess the renal blood perfusion with use of the image analysis software package in the color Doppler system.DESIGN: It was an experimental study on animals.SETTING: This study was conducted in

  6. Fetal ductus venosus flow velocity waveforms and maternal serum AFP before and after first-trimester transabdominal chorionic villus sampling

    C.A. Brezinka (Christoph); A.M. Hagenaars (A.); J.W. Wladimiroff (Juriy); F.J. Los


    textabstractDoppler flow velocity waveform recording in the fetal ductus venosus and umbilical artery as well as maternal blood sampling for serum alpha-fetoprotein (MSAFP) was performed before and after transabdominal chorion villus sampling (TACVS) in 36 women of advanced maternal age (≥ 36 years)

  7. Doppler assessment of hepatic venous waves for predicting large varices in cirrhotic patients

    Thomas Joseph


    Full Text Available Background/Aim: Color Doppler examination of changes in hepatic venous waveforms is being evaluated as a means of prediction of severity of portal hypertension and presence of esophageal varices. Normal hepatic venous waveform shows a triphasic pattern. In cirrhosis, this pattern changes to a biphasic or monophasic pattern. We aimed to study the sensitivity of loss of normal hepatic venous waveforms in predicting large varices in a cross-sectional analysis. Materials and Methods: All patients, admitted or attending the outpatient department, with a diagnosis of cirrhosis were included in the study. All patients were subjected to oesophagogastroduodenoscopy and Color Doppler examination, and waveform patterns in hepatic vein were recorded. The sensitivity and specificity of changes in waveform in detecting large varices were studied. Results : A total of 51 cases were examined. Triphasic waves were seen in 4 (7.8% cases, biphasic in 26 (51% cases, and monophasic in 21 (41.2% cases. Small varices were seen in 30 (58.8% cases and large varices in 21 (41.2% cases. The sensitivity of loss of the triphasic wave pattern in detecting significant varices (Grade 3 or 4 was very high (95.23% and negative predictive value was also high (75%. Severity of liver disease as indicated by Child-Pugh and MELD scores did not correlate with changes in hepatic venous waveforms. Conclusion : Loss of triphasic hepatic venous waveform is highly sensitive in predicting significant varices in patients with cirrhosis.

  8. Tendinopathy and Doppler activity

    Boesen, M I; Koenig, M J; Torp-Pedersen, S


    Intratendinous Doppler activity has been interpreted as an equivalent of neovessels in the Achilles tendon and as a sign of tendinosis (AT).......Intratendinous Doppler activity has been interpreted as an equivalent of neovessels in the Achilles tendon and as a sign of tendinosis (AT)....

  9. Ultrasonic colour Doppler imaging

    Evans, David H.; Jensen, Jørgen Arendt; Nielsen, Michael Bachmann


    Ultrasonic colour Doppler is an imaging technique that combines anatomical information derived using ultrasonic pulse-echo techniques with velocity information derived using ultrasonic Doppler techniques to generate colour-coded maps of tissue velocity superimposed on grey-scale images of tissue ...

  10. Comparative study on second harmonic contrast imaging with power Doppler sonography for quantification of the renal allografts microcirculation%二次谐波声学造影与多普勒能量图对移植肾血流灌注的对比研究

    王新明; 牟善初; 周桂芳; 敖建华


    Objective To assess the value of second harmonic contrast imaging(SHCI) in identifying viable the renal allografts blood flow perfusion in microcirculation.Methods Blood flow perfusion of thirty-six patients with renal allografts,included 6 renal allografts defeat,age range 20~61 years,were investigated by power Doppler imaging(PDI) and SHCI.The intravenous injection of agent was SHU-508A,and compared with pre-injection by quantitative assessment of acoustic densitometry (AD) of SHCI for the renal microstructure.Results There were sigllificant differences in the peak intensity,the area under the curve and the half-time of wash-out between pre-injection and injection contrast agent.The wash-in and wash-out curve showed the mountain peak shape.AD in the renal allografts with acute rejection was significantly lower than that in the control group(P<0.05).No contrast opacification of renal microstructure was present in 6 renal allografts defeat and the wash-in and wash-out curve appeared the straight line shape.Conclusions SHCI is a safe,efficient technology for assessing blood flow perfusion of renal allografts,which is different form the Doppler ultrasound and may prove a more sensitive indicator of allograft complication than PDI.%目的 谐波声学造影(SHCI)与声学定量(AD)和多普勒能量图成像(PDI)相对比,探讨SHCI对移植肾灌注诊断的价值.方法 对术后10 d内36例移植肾脏应用PDI和SHCI进行对比分析.结果 6例移植术失败者,灌注一清除曲线呈平直状,AD值无改变.其余病例造影剂灌注区的灌注-清除曲线均呈山峰状,峰值密度(PD)、灌注曲线下面积(AUC)、降支减半时间(HT)均较造影前显著增高(P<0.05),视觉判断差异有显著性.灌注不良区呈充盈缺损,AD值低,与正常区和正常移植肾比较差异有显著性(P<0.05),SHCI与PDI比较肾皮质灌注显像差异有显著性(P<0.05).结论 ①移植肾排异反应区灌注不良,AD值低;②SHCI在诊断肾皮质灌

  11. Ultrasonic colour Doppler imaging

    Evans, David H; Jensen, Jørgen Arendt; Nielsen, Michael Bachmann


    anatomy. The most common use of the technique is to image the movement of blood through the heart, arteries and veins, but it may also be used to image the motion of solid tissues such as the heart walls. Colour Doppler imaging is now provided on almost all commercial ultrasound machines, and has been......Ultrasonic colour Doppler is an imaging technique that combines anatomical information derived using ultrasonic pulse-echo techniques with velocity information derived using ultrasonic Doppler techniques to generate colour-coded maps of tissue velocity superimposed on grey-scale images of tissue...... vectors. This review briefly introduces the principles behind colour Doppler imaging and describes some clinical applications. It then describes the basic components of conventional colour Doppler systems and the methods used to derive velocity information from the ultrasound signal. Next, a number of new...

  12. An MSK Waveform for Radar Applications

    Quirk, Kevin J.; Srinivasan, Meera


    We introduce a minimum shift keying (MSK) waveform developed for use in radar applications. This waveform is characterized in terms of its spectrum, autocorrelation, and ambiguity function, and is compared with the conventionally used bi-phase coded (BPC) radar signal. It is shown that the MSK waveform has several advantages when compared with the BPC waveform, and is a better candidate for deep-space radar imaging systems such as NASA's Goldstone Solar System Radar.

  13. Radar Waveform Design in Active Communications Channel

    Ric A. Romero; Shepherd, Kevin D.


    In this paper, we investigate spectrally adaptive radar transmit waveform design and its effects on an active communication system. We specifically look at waveform design for point targets. The transmit waveform is optimized by accounting for the modulation spectrum of the communication system while trying to efficiently use the remaining spectrum. With the use of spectrally-matched radar waveform, we show that the SER detection performance of the communication system ...

  14. Comparison of three arterial pulse waveform classification techniques.

    Allen, J; Murray, A


    Peripheral pulse waveforms can become stretched and damped with increasing severity of peripheral vascular disease (PVD) and hence could provide valuable diagnostic information. This study compares the diagnostic performance of 3 established classification techniques (a linear discriminant classifier, a k-nearest neighbour classifier, and an artificial neural network) for the detection of lower limb arterial disease from pulse waveforms obtained using photoelectric plethysmography (PPG). Pulse waveforms and pre- and post-exercise Doppler ultrasound ankle to brachial pressure indices (ABPI) were obtained from patients attending a vascular measurement laboratory. A single PPG pulse from each big toe was recorded direct to computer, pre-processed, and then used as classifier input data. The correct classifier outputs were the corresponding ABPI diagnostic classification. Pulse and ABPI measurements from 100 legs were used as training data for each classifier, and the computed classifications for pulses from a further 266 legs were then compared with their ABPI diagnoses. The diagnostic accuracy of the artificial neural network (80%; was higher than for the optimized k-nearest neighbour classifier (k = 27, accuracy 76% and the linear discriminant classifier (71%). The Kappa measure of agreement which excludes chance was highest for the artificial neural network (57%) and significantly higher than that of the linear discriminant classifier (Kappa 40%, p < 0.05). The value of Kappa for the optimized k-nearest neighbour classifier (k = 27) was intermediate at 47%. This study has shown that classifiers can be taught to discriminate between small, and perhaps subtle, differences in features. We have demonstrated that artificial neural networks can be used to classify arterial pulse waveforms, and can perform better overall than k-nearest neighbour or linear discriminant classifiers for this application.

  15. One way Doppler Extractor. Volume 2: Digital VCO technique

    Nossen, E. J.; Starner, E. R.


    A feasibility analysis and trade-offs for a one-way Doppler extractor using digital VCO techniques is presented. The method of Doppler measurement involves the use of a digital phase lock loop; once this loop is locked to the incoming signal, the precise frequency and hence the Doppler component can be determined directly from the contents of the digital control register. The only serious error source is due to internally generated noise. Techniques are presented for minimizing this error source and achieving an accuracy of 0.01 Hz in a one second averaging period. A number of digitally controlled oscillators were analyzed from a performance and complexity point of view. The most promising technique uses an arithmetic synthesizer as a digital waveform generator.

  16. Generating nonlinear FM chirp waveforms for radar.

    Doerry, Armin Walter


    Nonlinear FM waveforms offer a radar matched filter output with inherently low range sidelobes. This yields a 1-2 dB advantage in Signal-to-Noise Ratio over the output of a Linear FM waveform with equivalent sidelobe filtering. This report presents design and implementation techniques for Nonlinear FM waveforms.

  17. Sonographic Findings in Fetal Renal Vein Thrombosis.

    Gerber, Rebecca E; Bromley, Bryann; Benson, Carol B; Frates, Mary C


    We present the sonographic findings of fetal renal vein thrombosis in a series of 6 patients. The mean gestational age at diagnosis was 31.2 weeks. Four cases were unilateral, and 2 were bilateral. The most common findings were renal enlargement and intrarenal vascular calcifications, followed by increased renal parenchymal echogenicity. Inferior vena cava thrombosis was found in 4 patients and common iliac vein thrombosis in 2. Fetal renal vein thrombosis is an uncommon diagnosis with characteristic sonographic findings. The presence of these findings should prompt Doppler interrogation of the renal vein and inferior vena cava to confirm the diagnosis.

  18. Doppler study of hepatic vein in cirrhotic patients: Correlation with liver dysfunction and hepatic hemodynamics

    KC Sudhamshu; Shoiichi Matsutani; Hitoshi Maruyama; Taro Akiike; Hiromitsu Saisho


    AIM: To elucidate the significance of Doppler measurements of hepatic vein in cirrhotic patients and to correlate with liver dysfunction and hepatic hemodynamics.METHODS: One hundred patients with liver cirrhosis and 60 non-cirrhotic controls were studied. Doppler waveforms were obtained from right hepatic vein and flow velocity measured during quiet respiration. Doppler measurements were also obtained from portal trunk,right portal vein and proper hepatic artery.RESULTS: Hepatic vein waveforms were classified into three classical patterns. Flat waveform was uncommon.Mean hepatic vein velocity was significantly higher in cirrhotic patients (12.7 ± 6.4 vs 5.1 ± 2.1 and 6.2 ± 3.2 cm/s; P < 0.0001). The poorer the grade of cirrhosis,the higher was the mean velocity. Maximum forward velocity was never greater than 40 cm/s in controls.Degree of ascites was found to be highly correlated with mean velocity. "Very high" group (≥ 20 cm/s) presented clinically with moderate to massive ascites. Correlations between right portal flow and mean velocity was significant (P < 0.0001, r = 0.687).CONCLUSION: Doppler waveforms of hepatic vein,which is independent of liver dysfunction, should be obtained during normal respiration. Mean hepatic vein velocity reflects the change in hepatic circulation associated with progression of liver cirrhosis. It can be used as a new parameter in the assessment of liver cirrhosis.

  19. Multistatic Tracking for Continous Active Sonar using Doppler-Bearing Measurements


    S. Coraluppi, Multistatic active sonar system interoperability, data fusion, and measures of performance, NURC Technical Report NURC -FR-2006-004...of Doppler sensitive and insensitive waveforms, NURC Technical Report SR-427, July 2005. [7] S. Nardone, V. Aidala, Observability Criteria For

  20. Doppler colour flow imaging of fetal intracerebral arteries relative to fetal behavioural states in normal pregnancy

    M.J. Noordam (Marja); F.M.E. Hoekstra (Franciska); W.C.J. Hop (Wim); J.W. Wladimiroff (Juriy)


    textabstractIn 14 normally developing term fetuses, the relationship between the blood flow velocity waveforms at cerebral arterial level (internal carotid artery, anterior, middle and posterior cerebral artery) and fetal behavioural states was studied using Doppler colour flow imaging. Behavioural

  1. Workflows for Full Waveform Inversions

    Boehm, Christian; Krischer, Lion; Afanasiev, Michael; van Driel, Martin; May, Dave A.; Rietmann, Max; Fichtner, Andreas


    Despite many theoretical advances and the increasing availability of high-performance computing clusters, full seismic waveform inversions still face considerable challenges regarding data and workflow management. While the community has access to solvers which can harness modern heterogeneous computing architectures, the computational bottleneck has fallen to these often manpower-bounded issues that need to be overcome to facilitate further progress. Modern inversions involve huge amounts of data and require a tight integration between numerical PDE solvers, data acquisition and processing systems, nonlinear optimization libraries, and job orchestration frameworks. To this end we created a set of libraries and applications revolving around Salvus (, a novel software package designed to solve large-scale full waveform inverse problems. This presentation focuses on solving passive source seismic full waveform inversions from local to global scales with Salvus. We discuss (i) design choices for the aforementioned components required for full waveform modeling and inversion, (ii) their implementation in the Salvus framework, and (iii) how it is all tied together by a usable workflow system. We combine state-of-the-art algorithms ranging from high-order finite-element solutions of the wave equation to quasi-Newton optimization algorithms using trust-region methods that can handle inexact derivatives. All is steered by an automated interactive graph-based workflow framework capable of orchestrating all necessary pieces. This naturally facilitates the creation of new Earth models and hopefully sparks new scientific insights. Additionally, and even more importantly, it enhances reproducibility and reliability of the final results.

  2. Why Waveform Correlation Sometimes Fails

    Carmichael, J.


    Waveform correlation detectors used in explosion monitoring scan noisy geophysical data to test two competing hypotheses: either (1) an amplitude-scaled version of a template waveform is present, or, (2) no signal is present at all. In reality, geophysical wavefields that are monitored for explosion signatures include waveforms produced by non-target sources that are partially correlated with the waveform template. Such signals can falsely trigger correlation detectors, particularly at low thresholds required to monitor for smaller target explosions. This challenge is particularly formidable when monitoring known test sites for seismic disturbances, since uncatalogued natural seismicity is (generally) more prevalent at lower magnitudes, and could be mistaken for small explosions. To address these challenges, we identify real examples in which correlation detectors targeting explosions falsely trigger on both site-proximal earthquakes (Figure 1, below) and microseismic "noise". Motivated by these examples, we quantify performance loss when applying these detectors, and re-evaluate the correlation-detector's hypothesis test. We thereby derive new detectors from more general hypotheses that admit unknown background seismicity, and apply these to real data. From our treatment, we derive "rules of thumb'' for proper template and threshold selection in heavily cluttered signal environments. Last, we answer the question "what is the probability of falsely detecting an earthquake collocated at a test site?", using correlation detectors that include explosion-triggered templates. Figure Top: An eight-channel data stream (black) recorded from an earthquake near a mine. Red markers indicate a detection. Middle: The correlation statistic computed by scanning the template against the data stream at top. The red line indicates the threshold for event declaration, determined by a false-alarm on noise probability constraint, as computed from the signal-absent distribution using

  3. Phenomenological gravitational waveforms from spinning coalescing binaries

    Sturani, R; Cadonati, L; Guidi, G M; Healy, J; Shoemaker, D; Vicere', A


    An accurate knowledge of the coalescing binary gravitational waveform is crucial for match filtering techniques, which are currently used in the observational searches performed by the LIGO-Virgo collaboration. Following an earlier paper by the same authors we expose the construction of analytical phenomenological waveforms describing the signal sourced by generically spinning binary systems. The gap between the initial inspiral part of the waveform, described by spin-Taylor approximants, and its final ring-down part, described by damped exponentials, is bridged by a phenomenological phase calibrated by comparison with the dominant spherical harmonic mode of a set of waveforms including both numerical and phenomenological waveforms of a different type. All waveforms considered describe equal mass systems with dimension-less spin magnitudes equal to 0.6. The noise-weighted overlap integral between numerical and phenomenological waveforms ranges between 0.93 and 0.98 for a wide span of mass values.

  4. The pulsatility index and the resistive index in renal arteries. Associations with long-term progression in chronic renal failure

    Petersen, L J; Petersen, J R; Talleruphuus, U


    The pulsatility index (PI) and the resistive index (RI) are used as pulsed-wave Doppler measurements of downstream renal artery resistance. PI and RI have been found to correlate with renal vascular resistance, filtration fraction and effective renal plasma flow in chronic renal failure. The aim...... of the present study was to evaluate the potential relationship between these indices and the rate of decline in renal function, as reflected by changes in different parameters of renal function in patients with chronic renal failure....

  5. The pulsatility index and the resistive index in renal arteries in patients with hypertension and chronic renal failure

    Petersen, L J; Petersen, J R; Ladefoged, S D


    The pulsatility index (PI) and the resistive index (RI) are used as pulsed-wave Doppler measurement of downstream renal artery resistance. Little information is available on their value in chronic renal failure and their correlation to parameters of renal function and haemodynamics. The aim...... was to compare PI and RI of renal arteries in healthy volunteers and in patients with hypertension and chronic renal failure, and furthermore to study the correlation of these indices to measurements of renal haemodynamics and function by standard methods in patients with renal failure and hypertension....

  6. Pulse subtraction Doppler

    Mahue, Veronique; Mari, Jean Martial; Eckersley, Robert J.; Caro, Colin G.; Tang, Meng-Xing


    Recent advances have demonstrated the feasibility of molecular imaging using targeted microbubbles and ultrasound. One technical challenge is to selectively detect attached bubbles from those freely flowing bubbles and surrounding tissue. Pulse Inversion Doppler is an imaging technique enabling the selective detection of both static and moving ultrasound contrast agents: linear scatterers generate a single band Doppler spectrum, while non-linear scatterers generate a double band spectrum, one being uniquely correlated with the presence of contrast agents and non-linear tissue signals. We demonstrate that similar spectrums, and thus the same discrimination, can be obtained through a Doppler implementation of Pulse Subtraction. This is achieved by reconstructing a virtual echo using the echo generated from a short pulse transmission. Moreover by subtracting from this virtual echo the one generated from a longer pulse transmission, it is possible to fully suppress the echo from linear scatterers, while for non-linear scatterers, a signal will remain, allowing classical agent detection. Simulations of a single moving microbubble and a moving linear scatterer subject to these pulses show that when the virtual echo and the long pulse echo are used to perform pulsed Doppler, the power Doppler spectrum allows separation of linear and non-linear moving scattering. Similar results are obtained on experimental data acquired on a flow containing either microbubble contrast agents or linear blood mimicking fluid. This new Doppler method constitutes an alternative to Pulse Inversion Doppler and preliminary results suggest that similar dual band spectrums could be obtained by the combination of any non-linear detection technique with Doppler demodulation.

  7. Experimental Study of Quantitative Analysis of Canine Renal Blood Flow Perfusion in Power Doppler Imaging%能量多普勒显像定量分析犬肾血流灌注的实验研究

    王建宏; 钱蕴秋; 贺建国; 朱霆; 赵振源; 李志宏


    Objective:To observe the accuracy of PDI in different canine renal blood perfusions by using computer analysis.Methods:Six healthy dogs were chosen and their main right renal arteries were exposed by surgery.Under the guidance of renal artery blood flow volume displayed on the electromagnetic flowmeter,different renal blood perfusion models were made with the micrometer constrictor.Then the color pixel area (CPA)and color value(CV) of PDI and the peak systolic velocity (PSV)and RI of renal segmental artery were calculated and analyzed.Results:The CPA、CV、PSV and RI tended to decrease with gradual reduction of the blood flow of renal artery and the decrease was especially significant when the renal blood flow reduced by 75%(P<0.05).The changes of PSV and RI were also significant(P<0.05).Conclusions:PDI can accurately reflect changes in the canine renal blood perfusions.%目的:应用计算机定量分析能量多普勒显像(PDI)显示犬肾不同程度血流灌注的准确性。方法:手术暴露犬右肾动脉,将电磁流量计和微米缩窄器固定其上,制备不同肾血流灌注模型。PDI显示肾血流图,计算机脱机分析肾血流图的彩色象素面积(CPA)和彩色亮度值(CV)。PWD测量肾段动脉的PSV、RI。结果:肾血流图CPA、CV及肾段动脉PSV、RI均与肾动脉血流量呈线性正相关(r=0.99)。以肾血流量减少50%和75%时,CPA减少明显(P<0.05和P<0.01)。而CV值仅在血流减少75%时下降明显(P<0.05)。PSV、RI均有明显变化(P<0.05)。结论:PDI可以较准确反映犬肾血流灌注的异常变化。


    于宁; 禹静; 杨雪


    Objective To investigate the value of color Doppler flow measurement in evaluation of primary nephrotic syndrome (PNS) complicating renal interstitial impairment. Methods Fifty-one PNS patients, according to the degree of impairment of renal interstitium. Were divided into mild-moderate-and severe-damage groups, and 25 healthy individuals served as controls. The blood stream parameters of segmental renal artery (SRA) and interlobar artery (IRA) were tested in all subjects. Re-sults In moderate-damage group, end-diastolic velocity (Vmin) of IRA stepped down, and the resistance index (RI) elevated, the differences were significant versus that in the control and mild-damage groups (F=5. 70-15.10,q=4. 49 - 5. 67,P<0.05)j the differences between severe-damage group and other groups were significant in terms of decreased peak velocity in systole and the end-diastolic velocity, and increased pulsed index (q=2. 88 - 7. 64.P<0. 05). Conclusion The extent of renal interstitial impairment is an important factor that influences the therapeutic efficacy and prognosis of PNS. Color Doppler renal blood flow measurement can reflect the degree of impairment of renal interstitium, which is conducive to judgement of the condition of the patients and their prognosis.%目的 了解肾脏彩色多普勒血流检测对原发性肾病综合征并肾间质损害的评估价值.方法 将51例原发性肾病综合征病人根据肾间质损害程度分为轻度损害组、中度损害组、重度损害组,25例健康对照者作为对照组;检测所有受检者肾脏段动脉( SRA)、叶间动脉(IRA)血流参数.结果 中度损害组肾IRA舒张末期最低血流速度(Vmin)减慢、阻力指数(RI)增高,与对照组及轻度损害组比较差异有显著性(F=5.70~15.10,q=4.49~5.67,P<0.05);重度损害组与其他组比较肾脏各级动脉最大血血流速度度、最小血血流速度度明显减慢,RI明显增高,差异有显著性(q=2.88~7.64,P<0.05).结论 肾间质损

  9. Utilidad de la relación aclaramiento de creatinina - índice de resistencia de la ecografía Doppler renal como predictor de rechazo agudo en riñones trasplantados

    R. Cobeñas


    Conclusión: La asociación IR mayor de 0,7 y Cl Cr 0-30 demostró ser útil para confirmar la posibilidad de rechazo renal agudo, al tener una buena especificidad (98,2% a pesar de su baja sensibilidad (53%.

  10. Diagnostic value of color Doppler ultrasound measurement of renal hemodynamic parameters for early pre-diction of the degree of diabetic renal damage in patients with diabetic nephropathy%彩色多普勒超声测量肾血流动力学参数对早期预测糖尿病肾病肾损害程度的诊断价值



    目的:探讨彩色多普勒超声测量肾血流动力学参数对早期预测糖尿病肾病(DN)肾损害程度的诊断价值。方法选取我院2013年1月至2015年12月收治的150例糖尿病肾病患者作为研究对象,根据24 h尿蛋白定量的不同分为3组,即尿蛋白正常组36例、早期DN组52例和临床期DN组62例,同时选取50名健康成人作为对照组。分别检查各组彩色多普勒超声,比较各组肾脏大小及血流成像。结果临床期DN组的肾脏主肾动脉(MRA)、肾窦部段动脉(SRA)、肾椎体叶间动脉(IRA)各取样点的Vsmax 均明显低于对照组(P<0.05),早期DN组仅IRA这一取样点的Vsmax明显低于对照组(P<0.01),但随着肾损害程度的加重,各取样点的Vsmax均逐渐降低。 DN组中尿蛋白正常组、早期DN组以及临床期DN组3组的MRA、SRA、IRA各取样点的Vdmin均明显低于对照组(P<0.01)。 DN组中尿蛋白正常组、早期DN组以及临床期DN组3组的MRA、SRA、I-RA各取样点的RI均明显高于对照组(P<0.05)。临床期DN组肾脏体积明显小于其余3组(P<0.01)。结论彩色多普勒超声测量肾血流动力学参数可有效反映出糖尿病肾病肾脏损害程度,对糖尿病肾病的早期诊断具有重要价值。%Objective To explore the diagnostic value of Color Doppler ultrasound measurement of renal hemodynamic parameters for the degree of diabetic renal damage in patients with diabetic nephropathy (DN). Methods One hundred and fifty cases with diabetic nephropathy (DN) in our hospital from January 2013 to December 2015 were selected as the research objects. They were divided into three groups, which were normal group with urinary pro-tein of normal level(36 cases), early DN group (52 cases) and clinical stage DN group(62 cases) according to the 24h urine protein quantity. At the same time, 50 cases of healthy adults were chosen as the control group. Patients in each group

  11. A Renal Perforating Artery Mistaken for Arterial Bleeding after Percutaneous Renal Biopsy: A Case Report

    Kim, Ye Lim; Lee, Chang Hee; Kim, Kyeong Ah; Park, Cheol Min [Korea University College of Medicine, Seoul (Korea, Republic of)


    Perirenal hematoma after a renal biopsy is a common complication that usually resolves spontaneously, but this rarely requires transfusions or surgical/radiological intervention. We report here on a case of a renal perforating artery that was mistaken for renal arterial bleeding in a 53-year-old woman who was complicated with perirenal hematoma after undergoing a percutaneous renal biopsy. On the color and pulsed wave Doppler ultrasonography, linear blood flow was seen in the perirenal hematoma, which extended perpendicularly from the renal parenchyma into the perirenal space, and this linear blood flow exhibited an arterial pulse wave. On CT angiography, the renal perforating artery was demonstrated as a curvilinear vessel coursing tangentially to the renal margin and we decided that it was a pseudolesion caused by the renal perforating artery. A renal perforating artery may be mistaken for renal arterial bleeding after a percutaneous renal biopsy. A renal perforating artery and arterial bleeding can be differentiated by the location and shape seen on a color Doppler examination and the pulse waves characteristics

  12. The Effect of Percutaneous Nephrolithotripsy with Pneumatic and Ultrasonic Lithotripsy on the Renal Perfusion by Using Color Doppler Ultrasound%彩色多普勒超声评价经皮肾镜超声弹道气压碎石术对肾血流灌注变化的影响

    孙萌; 马琳; 张树华; 王艳滨; 杨华


    目的 运用彩色多普勒超声评价经皮肾镜超声弹道气压碎石术治疗对肾血流灌注变化的影响.资料与方法 观察60例经皮肾镜超声弹道气压碎石术治疗的患者肾动脉血流彩色多普勒超声表现,对患者术前、术后各级肾动脉血流参数进行分析.结果 术后肾叶间动脉、段动脉收缩期峰值流速(PSV)、舒张末期流速(EDV)高于术前,差异有统计学意义(t=3.570、2.517、3.213、2.957,P< 0.05或P<0.01),阻力指数(RJ)术前、术后比较差异无统计学意义(t=0.808、1.099,均P>0.05).肾主动脉远心端、近心端PSV、EDV及肾主动脉近心端RI术前、术后比较差异无统计学意义(t=0.142、1.580、0.123、0.834、0.862,均P> 0.05),术后肾主动脉远心端RI低于术前,差异有统计学意义(t=2.197,P<0.05).结论 经皮肾镜超声弹道气压碎石术能有效改善肾内血管的血流灌注.%Purpose To evaluate the effect of percutaneous nephrolithotripsy with pneumatic and ultrasonic lithotripsy on renal perfusion by using color Doppler ultrasound. Materials and Methods A total of 60 patients with renal calculi who underwent percutaneous nephrolithotripsy with pneumatic and ultrasonic lithotripsy were enrolled in this study. The clinical data were analyzed retrospectively before and after surgery. Results The peak systolic velocity (PSV) and end-diastolic velocity (EDV) of renal interlobar artery and renal segmental artery showed significant difference between the patients with and without surgery. PSV and EDV increased remarkably after surgery (f=3.570, 2.517, 3.213, 2.957; P 0.05). The PSV and EDV of distal ends of main renal artery and proximal main renal artery, and RI of proximal main renal artery were not significant difference between the patients with and without surgery (t=0A42, 1.580, 0.123, 0.834, 0.862; all P > 0.05). The RI of distal main renal artery were significant difference between the patients with and without surgery, RI

  13. 彩色多普勒血流显像结合定量分析技术评价肾血流灌注的临床研究%Clinical study on renal flow perfusion using color Doppler flow imaging combined with quantitative analysis technique

    李薇玢; 林铤; 张艳容; 吕清; 王新房; 谢明星; 项飞翔; 陈玉媛; 刘莹莹; 郭美荣


    Objective To explore the clinical value of color Doppler flow imaging(CDFI) combined with quantitative analysis technique to evaluate renal flow perflusion. Methods Twenty patients with different renal diseases matched with healthy control subjects were examined with Philips iU22 CDFI system. CDFI system and Qlab quantitative technique were used to measure renal restrictive index(RI), vascularization index(VI), flow index(FI), vascularization-flow index (VFI). The patients all received renal single-photon emission computed tomography (SPECT) examination. Results The RI of 32 kidney with lower flow perfusion in SPECT were higher than in the contol group (P <0.01). VI,FI, VFI were lower than those in control(VI, VFI, P <0.01 ;FI, P <0.05). Conelusious The renal blood flow perfusion of patients with renal diseases are lower than that of healthy people. It has high clinical value using CDFI combined with quantitative analysis technique to evaluate the renal perfusion of the patients with renal diseases.%目的 探讨彩色多普勒血流显像结合血流定量分析技术评价肾血流灌注的临床意义.方法 采用Philips iU22彩色多普勒血流显像结合血流定量分析技术分别测量20例正常对照者和20例肾疾病患者的肾叶间动脉、小叶间动脉阻力指数(RI)、血管指数(VI)、血流指数(FI)、血管-血流指数(VFI),并进行比较分析.所有肾疾病患者均于彩色多普勒显像前后进行放射性核素肾动态扫描.结果 20例肾疾病患者单光子发射计算机断层显像检查(SPECT)显示血流灌注减少的32只肾叶间动脉、小叶间动脉RI值明显高于正常对照组(P<0.01),VI、FI、VFI值均明显低于正常对照组(VI,VFI,P<0.01;FI,P<0.05).结论 肾疾病患者的肾血流灌注显著低于正常对照组,利用彩色多普勒血流显像结合血流定量分析技术可以无创性定量评价肾血流灌注.

  14. The application value of color doppler ultrasonography in predicting the final outcome of a fetal renal pelvis separation%彩色多普勒超声对预测胎儿肾盂分离转归的应用价值

    李雪凤; 陈爱军


    Objective The application value of color doppler ultrasonography in predicting the final outcome of a fetal renal pelvis separation was designed for the prediction of the renal pelvis separation fetus outcome, the unnecessary damage of termination of pregnancy, and the Early treatment of the urinary system congenital malformation. Methods The pregnant women who had a fetal from October 2008 to January 2010 in our hospital were reviewed. Inclusion criteria: First time ultrasonic hint fetal renal pelvis separation (the standard of Stocks etc[1]: the standard of a fetal renal pelvis separation was renal pelvis APD ≥4mm before pregnant 33 weeks, renal pelvis APD ≥7mm after pregnancy 33 weeks). There are total 119 cases. Pregnancy that first discovered renal pelvis separation from fetal began, pregnant women must have (qu) ultrasound re-examination every 4 weeks, after the birth of neonatal to 1 year, monthly review within an ultrasonic parturition, finally observe the final outcome. All the data collected will be computerized with SPSS11.5 software process. Results ( 1 ) The difference of fetal kidney APD value between reducible group and irreducible group was statistically significant. ( 2 ) Through the receiver-operating characteristic curve ( characteristic curve, receive operating ROC curves) , predict the fetal renal pelvis separation outcome of pregnant women whose pregnancy ≥ 33 weeks and the meaningful APD boundary value( 15.5 mm) is obtained. Conclusion If APD ≥ 15.5 mm, there is great possibility to develop into irreducible hydronephrosis.%目的 应用彩色多普勒超声动态观察胎儿肾盂分离状态,为预测胎儿肾盂分离的转归、避免不必要的终止妊娠、及早治疗泌尿系统先天畸形,提供有价值的信息.方法 选择2008年10月-2010年1月在我院就诊的单胎孕妇,符合纳入排除标准者,首次超声提示胎儿肾盂分离[采用Stocks等[1]标准,孕33周以前肾盂前后径(APD)≥4 mm,孕33

  15. Fractal characteristics for binary noise radar waveform

    Li, Bing C.


    Noise radars have many advantages over conventional radars and receive great attentions recently. The performance of a noise radar is determined by its waveforms. Investigating characteristics of noise radar waveforms has significant value for evaluating noise radar performance. In this paper, we use binomial distribution theory to analyze general characteristics of binary phase coded (BPC) noise waveforms. Focusing on aperiodic autocorrelation function, we demonstrate that the probability distributions of sidelobes for a BPC noise waveform depend on the distances of these sidelobes to the mainlobe. The closer a sidelobe to the mainlobe, the higher the probability for this sidelobe to be a maximum sidelobe. We also develop Monte Carlo framework to explore the characteristics that are difficult to investigate analytically. Through Monte Carlo experiments, we reveal the Fractal relationship between the code length and the maximum sidelobe value for BPC waveforms, and propose using fractal dimension to measure noise waveform performance.

  16. Steerable Doppler transducer probes

    Fidel, H.F.; Greenwood, D.L.


    An ultrasonic diagnostic probe is described which is capable of performing ultrasonic imaging and Doppler measurement consisting of: a hollow case having an acoustic window which passes ultrasonic energy and including chamber means for containing fluid located within the hollow case and adjacent to a portion of the acoustic window; imaging transducer means, located in the hollow case and outside the fluid chamber means, and oriented to direct ultrasonic energy through the acoustic window toward an area which is to be imaged; Doppler transducer means, located in the hollow case within the fluid chamber means, and movably oriented to direct Doppler signals through the acoustic window toward the imaged area; means located within the fluid chamber means and externally controlled for controllably moving the Doppler transducer means to select one of a plurality of axes in the imaged area along which the Doppler signals are to be directed; and means, located external to the fluid chamber means and responsive to the means for moving, for providing an indication signal for identifying the selected axis.

  17. Visualization and analysis of lidar waveform data

    Olsen, Richard C.; Metcalf, Jeremy P.


    LiDAR waveform analysis is a relatively new activity in the area of laser scanning. The work described here is an exploration of a different approach to visualization and analysis, following the structure that has evolved for the analysis of imaging spectroscopy data (hyperspectral imaging). The waveform data are transformed into 3-dimensional data structures that provide xy position information, and a z-coordinate, which is the digitized waveform. This allows for representation of the data in spatial and waveform space, the extraction of characteristic spectra, and the development of regions of interest. This representation allows for the application of standard spectral classification tools such as the maximum likelihood classifier.

  18. Seismic waveform modeling over cloud

    Luo, Cong; Friederich, Wolfgang


    With the fast growing computational technologies, numerical simulation of seismic wave propagation achieved huge successes. Obtaining the synthetic waveforms through numerical simulation receives an increasing amount of attention from seismologists. However, computational seismology is a data-intensive research field, and the numerical packages usually come with a steep learning curve. Users are expected to master considerable amount of computer knowledge and data processing skills. Training users to use the numerical packages, correctly access and utilize the computational resources is a troubled task. In addition to that, accessing to HPC is also a common difficulty for many users. To solve these problems, a cloud based solution dedicated on shallow seismic waveform modeling has been developed with the state-of-the-art web technologies. It is a web platform integrating both software and hardware with multilayer architecture: a well designed SQL database serves as the data layer, HPC and dedicated pipeline for it is the business layer. Through this platform, users will no longer need to compile and manipulate various packages on the local machine within local network to perform a simulation. By providing users professional access to the computational code through its interfaces and delivering our computational resources to the users over cloud, users can customize the simulation at expert-level, submit and run the job through it.

  19. Doppler cooling a microsphere

    Barker, P F


    Doppler cooling the center-of-mass motion of an optically levitated microsphere via the velocity dependent scattering force from narrow whispering gallery mode (WGM) resonances is described. Light that is red detuned from the WGM resonance can be used to damp the center-of-mass motion in a process analogous to the Doppler cooling of atoms. Leakage of photons out of the microsphere when the incident field is near resonant with the narrow WGM resonance acts to damp the motion of the sphere. The scattering force is not limited by saturation, but can be controlled by the incident power. Cooling times on the order of seconds are calculated for a 20 micron diameter silica microsphere trapped within optical tweezers, with a Doppler temperature limit in the microKelvin regime.

  20. Evaluation of severe stenosis of end-to-end and end-to-side anastomosis of transplant renal artery with color Doppler sonography%彩色多普勒超声对端-端与端-侧吻合移植肾动脉重度狭窄的对比研究

    李建初; Robert J Min; Amelia Ng; David Trost; Michael Goldstein; Sandip Kupur; John Wang; David Serur; 姜玉新; 高敬; 张丽娜; 戴睛; 孟华; 蔡胜; 吕珂; 孝梦甦; 张一休


    目的 探讨两种吻合方式(端-端吻合与端-侧吻合)移植肾动脉重度狭窄(内径减少≥80%)的彩色多普勒超声诊断指标的差异.方法 回顾性分析彩色多普勒超声检查发现后并经数字减影血管造影(DSA)证实的38例移植肾动脉重度狭窄患者(端-端吻合和端-侧吻合各19例).超声测量髂动脉、移植肾动脉主干和吻合口峰值流速(PSV),肾内叶间动脉或段动脉PSV和加速时间(AT),计算狭窄处与狭窄近端PSV比值(简称PSV前比).结果 血管造影显示所有患者的动脉内径减少≥80%,狭窄部位位于髂动脉4例,吻合口20例和移植肾动脉14例.狭窄处PSV、髂动脉PSV及PSV前比在两种吻合方式之间差异均有统计学意义(P0.05).结论 两种吻合方式移植肾动脉重度狭窄患者的肾动脉血流动力学差异很可能是导致它们之间狭窄处PSV和PSV前比差异的主要原因.为了提高移植肾动脉重度狭窄的诊断准确性,应依据吻合方式来建立PSV前比的诊断阈值,而同-AT诊断阈值很可能适合两种吻合方式患者.%Objective To investigate differences in Doppler parameters between severe transplant renal artery stenosis (TRAS,arterial lumen reduction ≥80%) with end-to-end anastomosis and that with end-to-side anastomosis. Methods Color Doppler sonography(CDS) and digital subtraction angiography(DSA) images were reviewed retrospectively in 38 patients with severe TRAS (19 cases with end-to-end anastomosis and 19 cases with end-to-side anastomosis). All 38 cases with severe TRAS were initially diagnosed with CDS and confirmed by DSA afterwards. Doppler parameters,including the peak systolic velocity(PSV) in the renal, lilac, anastomosis site and segmental or interlobar artery, pre-PSV ratio (the ratio of the PSV at the stenotic site to that in the iliae artery), acceleration time(AT) in the intrarenal arteries, were measured or calculated. Results DSA demonstrated all patients with severe arterial

  1. Trauma renal Renal trauma

    Gerson Alves Pereira Júnior


    Full Text Available Apresentamos uma revisão sobre trauma renal, com ênfase na avaliação radiológica, particularmente com o uso da tomografia computadorizada, que tem se tornado o exame de eleição, ao invés da urografia excretora e arteriografia. O sucesso no tratamento conservador dos pacientes com trauma renal depende de um acurado estadiamento da extensão da lesão, classificado de acordo com a Organ Injury Scaling do Colégio Americano de Cirurgiões. O tratamento conservador não-operatório é seguro e consiste de observação contínua, repouso no leito, hidratação endovenosa adequada e antibioti- coterapia profilática, evitando-se uma exploração cirúrgica desnecessária e possível perda renal. As indicações para exploração cirúrgica imediata são abdome agudo, rápida queda do hematócrito ou lesões associadas determinadas na avaliação radiológica. Quando indicada, a exploração renal após controle vascular prévio é segura, permitindo cuidadosa inspeção do rim e sua reconstrução com sucesso, reduzindo a probabilidade de nefrectomia.We present a revision of the renal trauma with emphasis in the radiographic evaluation, particularly CT scan that it has largely replaced the excretory urogram and arteriogram in the diagnostic worh-up and management of the patient with renal trauma. The successful management of renal injuries depends upon the accurate assessment of their extent in agreement with Organ Injury Scaling classification. The conservative therapy managed by careful continuous observation, bed rest, appropriate fluid ressuscitation and prophylactic antibiotic coverage after radiographic staging for severely injured kidneys can yield favorable results and save patients from unnecessary exploration and possible renal loss. The indications for immediate exploratory laparotomy were acute abdomen, rapidly dropping hematocrit or associated injuries as determinated from radiologic evaluation. When indicated, renal exploration

  2. Pulse Doppler radar

    Alabaster, Clive


    This book is a practitioner's guide to all aspects of pulse Doppler radar. It concentrates on airborne military radar systems since they are the most used, most complex, and most interesting of the pulse Doppler radars; however, ground-based and non-military systems are also included. It covers the fundamental science, signal processing, hardware issues, systems design and case studies of typical systems. It will be a useful resource for engineers of all types (hardware, software and systems), academics, post-graduate students, scientists in radar and radar electronic warfare sectors and milit

  3. Doppler radar physiological sensing

    Lubecke, Victor M; Droitcour, Amy D; Park, Byung-Kwon; Singh, Aditya


    Presents a comprehensive description of the theory and practical implementation of Doppler radar-based physiological monitoring. This book includes an overview of current physiological monitoring techniques and explains the fundamental technology used in remote non-contact monitoring methods. Basic radio wave propagation and radar principles are introduced along with the fundamentals of physiological motion and measurement. Specific design and implementation considerations for physiological monitoring radar systems are then discussed in detail. The authors address current research and commercial development of Doppler radar based physiological monitoring for healthcare and other applications.

  4. Goldstone Solar System Radar Waveform Generator

    Quirk, Kevin J.; Patawaran, Ferze D.; Nguyen, Danh H.; Nguyen, Huy


    Due to distances and relative motions among the transmitter, target object, and receiver, the time-base between any transmitted and received signal will undergo distortion. Pre-distortion of the transmitted signal to compensate for this time-base distortion allows reception of an undistorted signal. In most radar applications, an arbitrary waveform generator (AWG) would be used to store the pre-calculated waveform and then play back this waveform during transmission. The Goldstone Solar System Radar (GSSR), however, has transmission durations that exceed the available memory storage of such a device. A waveform generator capable of real-time pre-distortion of a radar waveform to a given time-base distortion function is needed. To pre-distort the transmitted signal, both the baseband radar waveform and the RF carrier must be modified. In the GSSR, this occurs at the up-conversion mixing stage to an intermediate frequency (IF). A programmable oscillator (PO) is used to generate the IF along with a time-varying phase component that matches the time-base distortion of the RF carrier. This serves as the IF input to the waveform generator where it is mixed with a baseband radar waveform whose time-base has been distorted to match the given time-base distortion function producing the modulated IF output. An error control feedback loop is used to precisely control the time-base distortion of the baseband waveform, allowing its real-time generation. The waveform generator produces IF modulated radar waveforms whose time-base has been pre-distorted to match a given arbitrary function. The following waveforms are supported: continuous wave (CW), frequency hopped (FH), binary phase code (BPC), and linear frequency modulation (LFM). The waveform generator takes as input an IF with a time varying phase component that matches the time-base distortion of the carrier. The waveform generator supports interconnection with deep-space network (DSN) timing and frequency standards, and

  5. Renal arteriography

    ... Read More Acute arterial occlusion - kidney Acute kidney failure Aneurysm Atheroembolic renal disease Blood clots Renal cell carcinoma Renal venogram X-ray Review Date 1/5/2016 Updated by: Jason Levy, ...

  6. Optical arbitrary waveform characterization using linear spectrograms.

    Jiang, Zhi; Leaird, Daniel E; Long, Christopher M; Boppart, Stephen A; Weiner, Andrew M


    We demonstrate the first application of linear spectrogram methods based on electro-optic phase modulation to characterize optical arbitrary waveforms generated under spectral line-by-line control. This approach offers both superior sensitivity and self-referencing capability for retrieval of periodic high repetition rate optical arbitrary waveforms.

  7. Scanning laser Doppler vibrometry

    Brøns, Marie; Thomsen, Jon Juel

    With a Scanning Laser Doppler Vibrometer (SLDV) a vibrating surface is automatically scanned over predefined grid points, and data processed for displaying vibration properties like mode shapes, natural frequencies, damping ratios, and operational deflection shapes. Our SLDV – a PSV-500H from...

  8. The Doppler Pendulum Experiment

    Lee, C. K.; Wong, H. K.


    An experiment to verify the Doppler effect of sound waves is described. An ultrasonic source is mounted at the end of a simple pendulum. As the pendulum swings, the rapid change of frequency can be recorded by a stationary receiver using a simple frequency-to-voltage converter. The experimental results are in close agreement with the Doppler…

  9. Digital Waveform Generator Basedon FPGA

    Shoucheng Ding


    Full Text Available Field Programmable Gate Array (FPGA of the Cyclone II series was as the core processor of frequency meter and the Quartus II was as the development plat form. This article had designed the fully digital signal generator. It use dall-digital frequency synthesizer technology and FPGA programming implemented the three waveforms: sin wave and square wave and triangle wave. The frequency was adjustable through10- bit phase accumulator and the analog multiplier achieved amplitude modulation. Using 51soft nuclear FPGA wrote a C program and realized the in put control word. The 4 × 4 matrix keyboard inputted frequency or amplitude value and the LCD1602displayedthem. The test results show that the system has high precision, distortion and low.

  10. Bistatic Synthetic Aperture Radar Imaging of Moving Targets using Ultra-Narrowband Continuous Waveforms

    Wang, Ling


    We consider a synthetic aperture radar (SAR) system that uses ultra-narrowband continuous waveforms (CW) as an illumination source. Such a system has many practical advantages, such as the use of relatively simple, low-cost and low-power transmitters, and in some cases, using the transmitters of opportunity, such as TV, radio stations. Additionally, ultra-narrowband CW signals are suitable for motion estimation due to their ability to acquire high resolution Doppler information. In this paper, we present a novel synthetic aperture imaging method for moving targets using a bi-static SAR system transmitting ultra-narrowband continuous waveforms. Our method exploits the high Doppler resolution provided by ultra-narrowband CW signals to image both the scene reflectivity and to determine the velocity of multiple moving targets. Starting from the first principle, we develop a novel forward model based on the temporal Doppler induced by the movement of antennas and moving targets. We form the reflectivity image of t...

  11. Interpolation in waveform space: enhancing the accuracy of gravitational waveform families using numerical relativity

    Cannon, Kipp; Hanna, Chad; Keppel, Drew; Pfeiffer, Harald


    Matched-filtering for the identification of compact object mergers in gravitational-wave antenna data involves the comparison of the data stream to a bank of template gravitational waveforms. Typically the template bank is constructed from phenomenological waveform models since these can be evaluated for an arbitrary choice of physical parameters. Recently it has been proposed that singular value decomposition (SVD) can be used to reduce the number of templates required for detection. As we show here, another benefit of SVD is its removal of biases from the phenomenological templates along with a corresponding improvement in their ability to represent waveform signals obtained from numerical relativity (NR) simulations. Using these ideas, we present a method that calibrates a reduced SVD basis of phenomenological waveforms against NR waveforms in order to construct a new waveform approximant with improved accuracy and faithfulness compared to the original phenomenological model. The new waveform family is giv...

  12. Ultrasonography in chronic renal failure

    Buturovic-Ponikvar, Jadranka E-mail:; Visnar-Perovic, Alenka


    Many chronic renal diseases lead to the final common state of decrease in renal size, parenchymal atrophy, sclerosis and fibrosis. The ultrasound image show a smaller kidney, thinning of the parenchyma and its hyperechogenicity (reflecting sclerosis and fibrosis). The frequency of renal cysts increases with the progression of the disease. Ultrasound generally does not allow for the exact diagnosis of an underlying chronic disease (renal biopsy is usually required), but it can help to determine an irreversible disease, assess prognosis and avoid unnecessary diagnostic or therapeutic procedures. The main exception in which the ultrasound image does not show a smaller kidney with parenchymal atrophy is diabetic nephropathy, the leading cause of chronic and end-stage renal failure in developed countries in recent years. In this case, both renal size and parenchymal thickness are preserved until end-stage renal failure. Doppler study of intrarenal vessels can provide additional information about microvascular and parenchymal lesions, which is helpful in deciding for or against therapeutic intervention and timely planning for optimal renal replacement therapy option.

  13. Implementation of Pulse Radar Waveform Based on Software Radio Platform

    Wang Dong; Dong Jian; Xiao Shunping


    Based on the frequency and phase modulated signal, the authors design some commonly-used pulse radar baseband waveform, such as linear frequency modulated waveform, nonlinear frequency modulated waveform, Costas waveform, Barker coding waveform and multi-phase coded waveform, and the authors compare their performance, such as the peak side lobe ratio, the Rayleigh resolution in time and distance resolution. Then, based on the software radio platform NI PXIe-5644R, the authors design the timin...

  14. 基于LAS码与混沌的水下LPI波形设计%Underwater LPI Waveforms Design Based on LAS Code and Chaos

    洪嘉翔; 易红; 张娟; 张林让


    In view of the requirement for low probability of intercept (LPI) waveform characteristics in underwater detection, we serialize the chaotic sequences and use it to modulate the signal phase such that the basic waveform is obtained. Then the large area synchronized (LAS) codes are introduced for both interpulse and intrapulse modulations to design two new waveforms. Relying on the zero-delayed section and zero-Doppler section of an ambiguity function, we compare the discrimination property of the two new waveforms intuitively with four kinds of typical underwater detection waveforms, I.e. Continuous waveform (CW), linear frequency modulation (LFM) waveform, binary phase shift keying (BPSK) waveform and Costas waveform. Quantification analysis is made by their time resolution constants and frequency resolution constants. In addition, nonzero-Doppler section of an ambiguity function is used to compare their Doppler sensitivity characteristics under the ideal background, followed by a further comparison of reverberation suppression capability via the Q function. The results show that two new waveforms have outstanding distance resolution, Doppler tolerance and reverberation suppression capability over whole velocity ranges required by practical use.%鉴于水下探测对低截获概率(LPI)波形特性的需求,将混沌序列连续化后用以相位调制得到基本波形,然后用大区域同步(LAS)码对其分别作脉内、脉间调制设计出2种新波形,借助其模糊图的零延时切面和零频移切面直观比较了新波形与连续波(CW)、线性调频(LFM)、二进制相移键控(BPSK)、Costas等4种典型水下探测波形的分辨特性,并通过时间分辨常数和频率分辨常数作出量化分析.模糊图的非零频移切面被用以理想背景下各波形的多普勒敏感性比较,并通过Q函数进一步比较了它们的抗混响能力.对比分析表明,新设计的2种波形具有出色的距离分辨率和多普勒容忍性,且

  15. 彩色多普勒超声在急性百草枯中毒心肾损伤程度判断中的应用价值%Application value of color Doppler ultrasound in judgment of cardiac and renal injury during acute paraquat poisoning

    江锦雄; 郭黎红; 罗青; 肖清华


    目的 探讨彩色多普勒超声在急性百草枯中毒病情判定中应用的临床意义.方法 回顾性调查了我院收治的114例各型百草枯中毒的临床资料,尤其是重点分析了肾脏血流灌注、肾动脉阻力指数(RI)以及左心室收缩功能指标EF、FS、CO、SV、左室壁运动情况及其在治疗过程中的变化特点.结果 114例患者中,轻型中毒55例、中-重型中毒31例、暴发型中毒28例,共死亡36例,平均死亡率为31.6%.彩色多普勒超声检查显示:轻型中毒患者肾脏血流灌注以充满型或边缘缺损型为主,RI0.61±0.02,左心室收缩功能指标EF (55.2±3.9)%,FS(24.8±4.2)%,左室壁运动大部分正常,仅有2例左室壁搏动轻度减弱;中-重型中毒患者肾脏血流灌注以星点型为主,少数呈边缘缺损型或无血流型,RI 0.67±0.04,EF (42.2±4.6)%,FS (21.8±3.0)%,14例左室壁运动正常,17例左室壁搏动伴不同程度减弱;暴发型中毒患者肾脏血流灌注大部分呈无血流型或星点型为主,仅1例呈边缘缺损型,RI 0.74±0.05,EF (25.2±4.3)%,FS (18.9±3.8)%,全部病例左室壁运动有不同程度减弱.轻型与中-重型、暴发型测量指标RI、EF、FS的差异有统计学意义.结论 肾脏内部血流灌注情况及肾动脉RI均可反映肾功能受损害的程度,M型超声心动图通过测量左心室收缩功能指标EF、FS可提示心肌收缩功能是否受累及;肾脏血流灌注无血流型或星点型、RI>0.70、EF< 30%、FS< 14%提示预后差,且死亡率高,表明彩色多普勒超声在急性百草枯中毒心肾损伤程度的判断有重要临床价值.%Objective To investigate the clinical significance of color Doppler ultrasonography in the judgment of cardiac and renal damage during acute paraquat.Methods A retrospective survey of the clinical data of 114 acute paraquat poisoning cases in our hospital was made in the study,especially focused the ultrasound examination

  16. Improved retracking algorithm for oceanic altimeter waveforms

    Lifeng Bao; Yang Lu; Yong Wang


    Over the deep oceans without land/ice interference, the waveforms created by the return altimeter pulse generally follow the ocean model of Brown, and the corresponding range can be properly determined using the result from an onboard tracker. In the case of com-plex altimeter waveforms corrupted due to a variety of reasons, the processor on the satellite cannot properly determine the center of the leading edge, and range observations can be in error. As an efficacious method to improve the precision of those altimeter observations with complex waveforms, waveform retracking is required to reprocess the original returning pulse. Based on basic altimeter theory and the geometric feature of altimeter waveforms, we developed a new altimeter waveform retracker, which is valid for all altimeter wave-forms once there exists a reasonable returning signal. The performances of the existing Beta-5 retracker, threshold retracker, improved threshold retracker, and the new retracker are assessed in the experimental regions (China Seas and its adjacent regions), and the improvements in the accuracy of sea surface height are investigated by the difference between retracked altimeter observations and ref-erenced geoid. The comparisons denote that the new algorithm gives the best performance in both the open ocean and coastal regions. Also, the new retracker presents a uniform performance in the whole test region. Besides, there is a significant improvement in the short-wavelength precision and the spatial resolution of sea surface height after retracking process.

  17. Waveform Fingerprinting for Efficient Seismic Signal Detection

    Yoon, C. E.; OReilly, O. J.; Beroza, G. C.


    Cross-correlating an earthquake waveform template with continuous waveform data has proven a powerful approach for detecting events missing from earthquake catalogs. If templates do not exist, it is possible to divide the waveform data into short overlapping time windows, then identify window pairs with similar waveforms. Applying these approaches to earthquake monitoring in seismic networks has tremendous potential to improve the completeness of earthquake catalogs, but because effort scales quadratically with time, it rapidly becomes computationally infeasible. We develop a fingerprinting technique to identify similar waveforms, using only a few compact features of the original data. The concept is similar to human fingerprints, which utilize key diagnostic features to identify people uniquely. Analogous audio-fingerprinting approaches have accurately and efficiently found similar audio clips within large databases; example applications include identifying songs and finding copyrighted content within YouTube videos. In order to fingerprint waveforms, we compute a spectrogram of the time series, and segment it into multiple overlapping windows (spectral images). For each spectral image, we apply a wavelet transform, and retain only the sign of the maximum magnitude wavelet coefficients. This procedure retains just the large-scale structure of the data, providing both robustness to noise and significant dimensionality reduction. Each fingerprint is a high-dimensional, sparse, binary data object that can be stored in a database without significant storage costs. Similar fingerprints within the database are efficiently searched using locality-sensitive hashing. We test this technique on waveform data from the Northern California Seismic Network that contains events not detected in the catalog. We show that this algorithm successfully identifies similar waveforms and detects uncataloged low magnitude events in addition to cataloged events, while running to completion

  18. Laser Doppler flowmetry imaging

    Nilsson, Gert E.; Wardell, Karin


    A laser Doppler perfusion imager has been developed that makes possible mapping of tissue blood flow over surfaces with extensions up to about 12 cm X 12 cm. The He-Ne laser beam scans the tissue under study throughout 4096 measurement sites. A fraction of the backscattered and Doppler broadened light is detected by a photo diode positioned about 20 cm above the tissue surface. After processing, a signal that scales linearly with perfusion is stored in a computer and a color coded image of the spatial tissue perfusion is shown on a monitor. A full format scan is completed in about 4.5 minutes. Algorithms for calculating perfusion profiles and averages as well as substraction of one image from another, form an integral part of the system data analysis software. The perfusion images can also be exported to other software packages for further processing and analysis.

  19. Differential analysis of clinical features in atherosclerotic renal artery stenosis and benign nephrosclerosis



    Objective To analyze and compare the clinical characteristics of atherosclerotic renal artery stenosis (ARAS) and benign nephrosclerosis (BN) in order to distinguish the ARAS from BN. Methods A retrospective study was performed on 82 hypertensive patients with renal injury. Patients were divided into BN and ARAS group according to renal artery doppler scanning. The

  20. Early transient leg swelling at the side of renal transplant in two children.

    Koster-Kamphuis, L.; Die, C.E. van; Vliet, J.A. van der; Monnens, L.A.H.


    Two children are described with a huge leg swelling shortly after renal transplantation. The swelling was located at the side of the renal transplant. The swelling was caused by the compression of the iliac vein by the renal transplant combined with perirenal fluid collection. Doppler flow studies a

  1. Parallel Algorithm in Surface Wave Waveform Inversion


    In Surface wave waveform inversion, we want to reconstruct 3Dshear wav e velocity structure, which calculation beyond the capability of the powerful pr esent day personal computer or even workstation. So we designed a high parallele d algorithm and carried out the inversion on Parallel computer based on the part itioned waveform inversion (PWI). It partitions the large scale optimization pro blem into a number of independent small scale problems and reduces the computati onal effort by several orders of magnitude. We adopted surface waveform inversio n with a equal block(2°×2°) discretization.

  2. Optimal pseudorandom pulse position modulation ladar waveforms.

    Fluckiger, David U; Boland, Brian F; Marcus, Eran


    An algorithm for generating optimal pseudorandom pulse position modulation (PRPPM) waveforms for ladar ranging is presented. Bistatic ladar systems using Geiger-mode avalanche photodiodes require detection of several pulses in order to generate sufficient target statistics to satisfy some detection decision rule. For targets with large initial range uncertainty, it becomes convenient to transmit a pulse train with large ambiguity range. One solution is to employ a PRPPM waveform. An optimal PRPPM waveform will have minimal sidelobes: equivalent to 1 or 0 counts after the pulse correlation filter (compression). This can be accomplished by generating PRPPM pulse trains with optimal or minimal sidelobe autocorrelation.

  3. Scanning laser Doppler vibrometry


    With a Scanning Laser Doppler Vibrometer (SLDV) a vibrating surface is automatically scanned over predefined grid points, and data processed for displaying vibration properties like mode shapes, natural frequencies, damping ratios, and operational deflection shapes. Our SLDV – a PSV-500H from Polytec Inc. – was acquired and put to operation in October 2014, paid by a sub-donation of DKK 1,5 mill. of the total VILLUM CASMaT grant. Opening possibilities of measuring complicated vibration shapes...

  4. Holographic laser Doppler ophthalmoscopy

    Simonutti, Manuel; Sahel, J A; Gross, Michel; Samson, Benjamin; Magnain, Caroline; Atlan, Michael; 10.1364/OL.35.001941


    We report laser Doppler ophthalmoscopic fundus imaging in the rat eye with near-IR heterodyne holography. Sequential sampling of the beat of the reflected radiation against a frequency-shifted optical local oscillator is made onto an array detector. Wide-field maps of fluctuation spectra in the 10 Hz to 25 kHz band exhibit angiographic contrasts in the retinal vascular tree without requirement of an exogenous marker.

  5. Laser double Doppler flowmeter

    Poffo, L.; Goujon, J.-M.; Le Page, R.; Lemaitre, J.; Guendouz, M.; Lorrain, N.; Bosc, D.


    The Laser Doppler flowmetry (LDF) is a non-invasive method for estimating the tissular blood flow and speed at a microscopic scale (microcirculation). It is used for medical research as well as for the diagnosis of diseases related to circulatory system tissues and organs including the issues of microvascular flow (perfusion). It is based on the Doppler effect, created by the interaction between the laser light and tissues. LDF measures the mean blood flow in a volume formed by the single laser beam, that penetrate into the skin. The size of this measurement volume is crucial and depends on skin absorption, and is not directly reachable. Therefore, current developments of the LDF are focused on the use of always more complex and sophisticated signal processing methods. On the other hand, laser Double Doppler Flowmeter (FL2D) proposes to use two laser beams to generate the measurement volume. This volume would be perfectly stable and localized at the intersection of the two laser beams. With FL2D we will be able to determine the absolute blood flow of a specific artery. One aimed application would be to help clinical physicians in health care units.

  6. Infarction of renal transplant with extrarenal excretion of Tc-99m MAG{sub 3} demonstrated by renal scintigraphy

    Lim, Seok Tae; Kim, Min Woo; Sohn, Myung Hee [Chonbok National University Medical School, Chonju (Korea, Republic of)


    A 38-year-old woman with end stage renal disease received a living related donor-renal transplant to the right iliac fossa. She developed anuria a week later. Tc-99m MAG{sub 3} renal scintigraphy demonstrated no perfusion, uptake, or excretion of the radioactive tracer from the renal transplant. The expected area of the renal allograft appeared as a photopenic area with increased rim activity. The gallbladder and bowel activities were observed on delayed images at 24 hours. There was no blood flow within the renal artery on renal doppler examination. This case shows total absence of perfusion and function in the infarcted renal transplant with extrarenal excretion of Tc-99m MAG{sub 3} caused by acute renal artery thrombosis.

  7. Selection of Carrier Waveforms for PWM Inverter

    陈国呈; 屈克庆; 许春雨; 孙承波


    In this paper the influence of different carrier waveforms upon the output characteristics of PWM inverter is described in detail. When a triangular carrier waveform is used in hard-switching PWM inverters, harmonics exist in the neighborhood of the output frequency of the inverter output voltage and current due to the dead time. The triangular carrier waveform used in soft-switching PWM inverter will cause difficulties in controlling resonance-trigger time, higher loss in the resonant circuit, and less utilization of the DC bus voltage. If a sawtooth carrier is used in hard-switching PWM inverter, there will be severe distortion in the current waveform. When sawtooth carriers with alternate positive and negative slopes are used in soft-switching PWM inverters, the resonancetrigger time is easy to control, and distortion in the output voltage and current caused by the dead time will not appear.

  8. Renal transplantation in a child with thrombosed inferior vena cava

    Surjeet Kumar


    Full Text Available The external iliac vein is commonly used in renal transplantation for vascular anastomosis of the allograft renal vein. However, there are rare instances when the transplant surgeon may encounter thrombosis of the ilio-caval vein during surgery, making renal transplantation a challenge. Often, these patients are considered unsuitable for renal transplantation. We report a case of thrombosis of the inferior vena cava in an asymptomatic pediatric patient in whom the splenic vein was used, at transplantation, for venous drainage. This case highlights that pre-operative Doppler screening should be performed in all potential renal transplant recipients.

  9. High-Voltage, Asymmetric-Waveform Generator

    Beegle, Luther W.; Duong, Tuan A.; Duong, Vu A.; Kanik, Isik


    The shapes of waveforms generated by commercially available analytical separation devices, such as some types of mass spectrometers and differential mobility spectrometers are, in general, inadequate and result in resolution degradation in output spectra. A waveform generator was designed that would be able to circumvent these shortcomings. It is capable of generating an asymmetric waveform, having a peak amplitude as large as 2 kV and frequency of several megahertz, which can be applied to a capacitive load. In the original intended application, the capacitive load would consist of the drift plates in a differential-mobility spectrometer. The main advantage to be gained by developing the proposed generator is that the shape of the waveform is made nearly optimum for various analytical devices requiring asymmetric-waveform such as differential-mobility spectrometers. In addition, this waveform generator could easily be adjusted to modify the waveform in accordance with changed operational requirements for differential-mobility spectrometers. The capacitive nature of the load is an important consideration in the design of the proposed waveform generator. For example, the design provision for shaping the output waveform is based partly on the principle that (1) the potential (V) on a capacitor is given by V=q/C, where C is the capacitance and q is the charge stored in the capacitor; and, hence (2) the rate of increase or decrease of the potential is similarly proportional to the charging or discharging current. The proposed waveform generator would comprise four functional blocks: a sine-wave generator, a buffer, a voltage shifter, and a high-voltage switch (see Figure 1). The sine-wave generator would include a pair of operational amplifiers in a feedback configuration, the parameters of which would be chosen to obtain a sinusoidal timing signal of the desired frequency. The buffer would introduce a slight delay (approximately equal to 20 ns) but would otherwise

  10. Color doppler energy (CDE) : initial ten-months experience

    Ro, Young Jin; Son, Hyun Ju; Lee, Suck Hong; Kim, Byung Soo [Pusan National Univ. College of Medicine, Pusan (Korea, Republic of); Han, Kook Sang; Nam, SAng Hwa; Lee, Keum Seob [Haedong Hospital, Pusan (Korea, Republic of); Shin Se Kwon [Daedong Hospital, Pusan (Korea, Republic of)


    Color Doppler imaging(CDI) has shortcomings, including random noise, aliasing, and angle dependence. To overcome these, a method using CD US, termed power doppler or Color Doppler Energy(CDE), has recently been introduced. The purpose of this study was to show the clinical usefulness of CDE. We retrospectively analyzed the CDI and CDE of 61 cases(20 renal pseudotumors, 8 musculoskeletal inflammations, 17 epididymitis or epididymo-orchitis, 3 varicoceles, 1 normal testis, 1 hepatocellualr carcinoma, 7 renal cell carcinoma, 1 renal angiomyolipoma, and 3 splenic varices). CDI and CDE scans were obtained at the same region with constant scan plane. The color gain was increased until noise first became perceptible, and scans were always obtained in such a way that the maximum amount of vascularity was shown. Thereafter, the vascularity, vascular displacement, and the vascular relationship between CDI and CDE were compared. In 17 of 20 cases of pseudotumor in the kidney, normal vascularity was identified in CDI and CDE, but was more cleary visible in CDE. In three cases, there was no visible vascularity in CDI, but normal vascularity in CDE. In eight cases of musculoskeletal inflammation and 17 cases of epididymitis with or without orchitis, the vascularity was increased due to hyperemia, which was more prominently seen in CDE than in CDI. In three varicoceles, CDE appeared to be better in demonstrating low velocity flow. In one patient who was suspected of having acute testicular torsion, CDE was helpful in excluding this suspicion. In one case of hepatocellualr carcinoma, seven cases of renal cell carcinoma, one case of renal angiomyolipoma, and three cases of splenic varices, CDE was better than CDI in showing the vascularity, vascular relationship, and vascular displacement.

  11. Role of kidney Doppler ultrasonography in the diagnosis and management of anuric kidney failure.

    Zand, Ladan; King, Bernard F; Qian, Qi


    Kidney perfusion can be acutely compromised by many factors including reduced systemic blood pressure and elevated intra-abdominal pressure. We present a case of near complete absence of kidney perfusion in a 57-year-old man with heart failure and new onset ascites. The renal perfusion defect was directly detected by Doppler ultrasonography. Immediate decompression with large-volume paracentesis restored the kidney perfusion and kidney function. This case illustrates that renal ultrasonography with Doppler flow analysis in appropriate settings can serve as an important adjunct in the diagnosis and treatment of acute oligoanuric kidney failure. Timely reversal of the perfusion defect can rescue kidney function.

  12. GRC GSFC TDRSS Waveform Metrics Report

    Mortensen, Dale J.


    The report presents software metrics and porting metrics for the GGT Waveform. The porting was from a ground-based COTS SDR, the SDR-3000, to the CoNNeCT JPL SDR. The report does not address any of the Operating Environment (OE) software development, nor the original TDRSS waveform development at GSFC for the COTS SDR. With regard to STRS, the report presents compliance data and lessons learned.

  13. Georgia Tech Catalog of Gravitational Waveforms

    Jani, Karan; Clark, James A; London, Lionel; Laguna, Pablo; Shoemaker, Deirdre


    This paper introduces a catalog of gravitational waveforms from the bank of simulations by the numerical relativity effort at Georgia Tech. Currently, the catalog consists of 452 distinct waveforms from more than 600 binary black hole simulations: 128 of the waveforms are from binaries with black hole spins aligned with the orbital angular momentum, and 324 are from precessing binary black hole systems. The waveforms from binaries with non-spinning black holes have mass-ratios $q = m_1/m_2 \\le 15$, and those with precessing, spinning black holes have $q \\le 8$. The waveforms expand a moderate number of orbits in the late inspiral, the burst during coalescence, and the ring-down of the final black hole. Examples of waveforms in the catalog matched against the widely used approximate models are presented. In addition, predictions of the mass and spin of the final black hole by phenomenological fits are tested against the results from the simulation bank. The role of the catalog in interpreting the GW150914 even...

  14. Georgia tech catalog of gravitational waveforms

    Jani, Karan; Healy, James; Clark, James A.; London, Lionel; Laguna, Pablo; Shoemaker, Deirdre


    This paper introduces a catalog of gravitational waveforms from the bank of simulations by the numerical relativity effort at Georgia Tech. Currently, the catalog consists of 452 distinct waveforms from more than 600 binary black hole simulations: 128 of the waveforms are from binaries with black hole spins aligned with the orbital angular momentum, and 324 are from precessing binary black hole systems. The waveforms from binaries with non-spinning black holes have mass-ratios q = m 1/m 2 ≤ 15, and those with precessing, spinning black holes have q ≤ 8. The waveforms expand a moderate number of orbits in the late inspiral, the burst during coalescence, and the ring-down of the final black hole. Examples of waveforms in the catalog matched against the widely used approximate models are presented. In addition, predictions of the mass and spin of the final black hole by phenomenological fits are tested against the results from the simulation bank. The role of the catalog in interpreting the GW150914 event and future massive binary black-hole search in LIGO is discussed. The Georgia Tech catalog is publicly available at

  15. Renal Osteodystrophy

    Aynur Metin Terzibaşoğlu


    Full Text Available Chronic renal insufficiency is a functional definition which is characterized by irreversible and progressive decreasing in renal functions. This impairment is in collaboration with glomeruler filtration rate and serum creatinine levels. Besides this, different grades of bone metabolism disorders develop in chronic renal insufficiency. Pathologic changes in bone tissue due to loss of renal paranchyme is interrelated with calcium, phosphorus vitamine-D and parathyroid hormone. Clinically we can see high turnover bone disease, low turnover bone disease, osteomalacia, osteosclerosis and osteoporosis in renal osteodystropy. In this article we aimed to review pathology of bone metabolism disorders due to chronic renal insufficiency, clinic aspects and treatment approaches briefly.

  16. Bistatic synthetic aperture radar imaging using ultraNarrowband continuous waveforms.

    Wang, Ling; Yazici, Birsen


    We consider synthetic aperture radar (SAR) imaging using ultra-narrowband continuous waveforms (CW). Due to the high Doppler resolution of CW signals, we refer to this imaging modality as Doppler Synthetic Aperture Radar (DSAR). We present a novel model and an image formation method for the bistatic DSAR for arbitrary imaging geometries. Our bistatic DSAR model is formed by correlating the translated version of the received signal with a scaled or frequencyshifted version of the transmitted CW signal over a finite time window. High frequency analysis of the resulting model shows that the correlated signal is the projections of the scene reflectivity onto the bistatic iso-Doppler curves. We next use microlocal techniques to develop a filtered-backprojection (FBP) type image reconstruction method. The FBP inversion results in backprojection of the correlated signal onto the bistatic iso- Doppler curves as opposed to the bistatic iso-range curves, performed in the traditional wideband SAR imaging. We show that our method takes advantage of the velocity, as well as the acceleration of the antennas in certain directions to form a high resolution SAR image. Our bistatic DSAR imaging method is applicable for arbitrary flight trajectories, nonflat topography, and can accommodate system related parameters. We present resolution analysis and extensive numerical experiments to demonstrate the performance of our imaging method.

  17. Wave reflection quantification based on pressure waveforms alone--methods, comparison, and clinical covariates.

    Hametner, Bernhard; Wassertheurer, Siegfried; Kropf, Johannes; Mayer, Christopher; Holzinger, Andreas; Eber, Bernd; Weber, Thomas


    Within the last decade the quantification of pulse wave reflections mainly focused on measures of central aortic systolic pressure and its augmentation through reflections based on pulse wave analysis (PWA). A complementary approach is the wave separation analysis (WSA), which quantifies the total amount of arterial wave reflection considering both aortic pulse and flow waves. The aim of this work is the introduction and comparison of aortic blood flow models for WSA assessment. To evaluate the performance of the proposed modeling approaches (Windkessel, triangular and averaged flow), comparisons against Doppler measurements are made for 148 patients with preserved ejection fraction. Stepwise regression analysis between WSA and PWA parameters are performed to provide determinants of methodological differences. Against Doppler measurement mean difference and standard deviation of the amplitudes of the decomposed forward and backward pressure waves are comparable for Windkessel and averaged flow models. Stepwise regression analysis shows similar determinants between Doppler and Windkessel model only. The results indicate that the Windkessel method provides accurate estimates of wave reflection in subjects with preserved ejection fraction. The comparison with waveforms derived from Doppler ultrasound as well as recently proposed simple triangular and averaged flow waves showed that this approach may reduce variability and provide realistic results.

  18. Platform for Postprocessing Waveform-Based NDE

    Roth, Don


    Taking advantage of the similarities that exist among all waveform-based non-destructive evaluation (NDE) methods, a common software platform has been developed containing multiple- signal and image-processing techniques for waveforms and images. The NASA NDE Signal and Image Processing software has been developed using the latest versions of LabVIEW, and its associated Advanced Signal Processing and Vision Toolkits. The software is useable on a PC with Windows XP and Windows Vista. The software has been designed with a commercial grade interface in which two main windows, Waveform Window and Image Window, are displayed if the user chooses a waveform file to display. Within these two main windows, most actions are chosen through logically conceived run-time menus. The Waveform Window has plots for both the raw time-domain waves and their frequency- domain transformations (fast Fourier transform and power spectral density). The Image Window shows the C-scan image formed from information of the time-domain waveform (such as peak amplitude) or its frequency-domain transformation at each scan location. The user also has the ability to open an image, or series of images, or a simple set of X-Y paired data set in text format. Each of the Waveform and Image Windows contains menus from which to perform many user actions. An option exists to use raw waves obtained directly from scan, or waves after deconvolution if system wave response is provided. Two types of deconvolution, time-based subtraction or inverse-filter, can be performed to arrive at a deconvolved wave set. Additionally, the menu on the Waveform Window allows preprocessing of waveforms prior to image formation, scaling and display of waveforms, formation of different types of images (including non-standard types such as velocity), gating of portions of waves prior to image formation, and several other miscellaneous and specialized operations. The menu available on the Image Window allows many further image

  19. Evaluation of Haemodynamic Changes of Proximal Arterial Occlusion in the Lower Extremities by Spectrum Doppler Ultrasonography

    Z Wang


    Full Text Available Objective: The objective is to analyse the changes of haemodynamic and Doppler ultrasonography spectrum in the proximal arterial occlusion of lower extremities, and to explore the value of spectrum Doppler ultrasonography in the diagnosis of lower extremity arterial occlusive disease. Methods: Thirty-four patients (thirty-nine occlusion arteries were examined with two-dimensional ultrasound combined with colour Doppler flow imaging (CDFI, and the results were compared. Result: The waveform shape in the artery proximal to the occlusion shows that blood flow velocity becomes slower, and diastolic reverse wave slowly disappears even upward. Systolic waveform records a steep upstroke, a slow downstroke and a shoulder on the downstroke. The appearance of the shoulder on the downstroke is earlier than the diastolic upward wave. The differences of peak systolic velocity, acceleration time, deceleration time, systolic acceleration, deceleration, diastolic reverse flow velocity, systolic acceleration time/systolic duration and systolic deceleration time/systolic duration in the proximal occlusion segment compared with the control group are statistically significant (p < 0.05. Conclusion: Artery occlusion can lead to haemodynamic response and spectrum waveform change. Timely discovery of the changes of the spectrum can be of clinical significance in the diagnosis of lower extremity arterial occlusive disease.

  20. US detection of renal and ureteral calculi in patients with suspected renal colic

    Vallone, Gianfranco; Napolitano, Giuseppina; Fonio, Paolo; Antinolfi, Gabriele; Romeo, Antonio; Macarini, Luca; Genovese, Eugenio Annibale; Brunese, Luca


    Purpose The purpose of this study was to determine whether the color Doppler twinkling sign could be considered as an additional diagnostic feature of small renal lithiasis (_5mm). Methods 181 patients underwent CT scans performed for other pathologies; the images were also analyzed by a radiologists to identify the incidental presence of renal lithiasis equal to or smaller than 5 mm. These patients underwent an abdominal ultrasound examination, including grayscale analysis of the kidneys and...

  1. Pulsed photoacoustic Doppler flow measurements in blood-mimicking phantoms

    Brunker, J.; Beard, P.


    The feasibility of making spatially resolved measurements of blood flow using pulsed photoacoustic Doppler techniques has been explored. Doppler time shifts were quantified via cross-correlation of pairs of photoacoustic waveforms generated within a blood-simulating phantom using pairs of laser light pulses. The photoacoustic waves were detected using a focussed or planar PZT ultrasound transducer. For each flow measurement, a series of 100 waveform pairs was collected. Previous data processing methods involved rejection of poorly correlated waveform pairs; the modal velocity value and standard deviation were then extracted from the selected distribution of velocity measurements. However, the data selection criteria used in this approach is to some extent arbitrary. A new data analysis protocol, which involves averaging the 100 cross-correlation functions and thus uses all of the measured data, has been designed in order to prevent exclusion of outliers. This more rigorous approach has proved effective for quantifying the linear motion of micron-scale absorbers imprinted on an acetate sheet moving with velocities in the range 0.14 to 1.25 ms-1. Experimental parameters, such as the time separation between the laser pulses and the transducer frequency response, were evaluated in terms of their effect on the accuracy, resolution and range of measurable velocities. The technique was subsequently applied to fluid phantoms flowing at rates less than 5 mms-1 along an optically transparent tube. Preliminary results are described for three different suspensions of phenolic resin microspheres, and also for whole blood. Velocity information was obtained even under non-optimal conditions using a low frequency transducer and a low pulse repetition frequency. The distinguishing advantage of pulsed rather than continuous-wave excitation is that spatially resolved velocity measurements can be made. This offers the prospect of mapping flow within the microcirculation and thus

  2. Comparisons between PW Doppler system and enhanced FM Doppler system

    Wilhjelm, Jens E.; Pedersen, P. C.


    This paper presents a new implementation of an echo-ranging FM Doppler system with improved performance, relative to the FM Doppler system reported previously. The use of long sweeps provides a significant reduction in peak to average power ratio compared to pulsed wave (PW) emission. A PW Doppler...... system exploits the direct relationship between arrival time of the received signal and range from the transducer. In the FM Doppler systems, a similar relationship exists in the spectral domain of the demodulated received signals, so that range is represented by frequency. Thus, a shift in location...... of moving scatterers between consecutive emissions corresponds to a frequency shift in the spectral signature. The improvement relative to the earlier version of the FM Doppler system is attained by utilizing cross-correlation of real spectra rather than of magnitude spectra for assessing flow velocity...

  3. ANL Doppler flowmeter

    Karplus, H. B.; Raptis, A. C.; Lee, S.; Simpson, T.


    A flowmeter has been developed for measuring flow velocity in hot slurries. The flowmeter works on an ultrasonic Doppler principle in which ultrasound is injected into the flowing fluid through the solid pipe wall. Isolating waveguides separate the hot pipe from conventional ultrasonic transducers. Special clamp-on high-temperature transducers also can be adapted to work well in this application. Typical flows in pilot plants were found to be laminar, giving rise to broad-band Doppler spectra. A special circuit based on a servomechanism sensor was devised to determine the frequency average of such a broad spectrum. The device was tested at different pilot plants. Slurries with particulates greater than 70 microns (0.003 in.) yielded good signals, but slurries with extremely fine particulates were unpredictable. Small bubbles can replace the coarse particles to provide a good signal if there are not too many. Successful operation with very fine particulate slurries may have been enhanced by the presence of microbubbles.

  4. Colour doppler ultrasound assessment of the normal neonatal hip

    Ortiz-Neira, C.L. [Dept. of Diagnostic Imaging, Alberta Children' s Hospital, Calgary, Alberta (Canada)], E-mail:; Laffan, E.; Daneman, A. [Dept. of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario (Canada); Fong, K. [Dept. of Diagnostic Imaging, Mount Sinai Hospital, Toronto, Ontario (Canada); Roposch, A. [Dept. of Orthopedic Surgery, The Hospital for Sick Children, Toronto, Ontario (Canada); Great Ormond Street Hospital, Inst. of Child Health, Univ. College London, London (United Kingdom)


    To determine the morphology and hemodynamic characteristics of the arterial vessels of the proximal femur according to specific anatomic regions in asymptomatic neonates in 2 pediatric-based health care institutions. Forty-three neonates (29 female, 14 male; age range, 2 d-3 mo; median age, 3 d) were enrolled in the study. Thirty-two (37%) of 86 hips were classified as Graf type IIA joints (mean alpha angle, 56.0{sup o} {+-} 2.7{sup o}), and 54 (63%) were classified as type I joints (mean alpha angle, 65.0{sup o} {+-} 4.6{sup o}). Colour and spectral Doppler imaging identified vessels running along the acetabular labrum, epiphyseal vessels, and femoral neck. We showed 4 different patterns of vascularity of the hips: radial, parallel, mixed radial-parallel, and indeterminate, however, they were not related to the hip maturity (P = .3, coronal plane; P = .62, transverse plane) or to the amount of colour pixels identified in each region (P = .35). The mean number of pixels in the ligamentum teres region was significantly higher than that in other regions of interest (P =.03). Except for the acetabular labrum arteries, Doppler spectrum waveforms of proximal femur arteries presented with low resistivity. There was a tendency towards females' acetabular arteries presenting with lower peak systolic velocities than males' acetabular arteries (P =.06). Colour Doppler spectrum waveforms and intensity of vascularity in normal neonatal hips differ according to the anatomic region under evaluation. This observation deserves further investigation on its role on the physiopathogenesis of neonatal hip disorders. (author)

  5. The value of color doppler ultrasonography in detecting the hemodynamic changes of renal artery before and after drug treatment in severe preeclampsia pregnant women%彩超评价重度子痫前期孕妇药物治疗前后肾动脉血流动力学变化的应用价值

    陈小聪; 徐立新; 潘高云; 朱张茜; 张红萍


    目的:应用彩色多普勒超声检测妊娠高血压疾病重度子痫前期孕妇药物治疗前后肾动脉血流的参数变化特点,评价其临床应用价值.方法:以正常孕妇100例为对照组,选取经临床确诊的30例重度子痫前期孕妇作为治疗前组,以该病例组药物治疗后作为治疗后组.采用SEQUOIA 512型超声诊断仪、阿洛卡a5型超声诊断仪,探头频率3.5~5.0 MHz,观察各组肾内结构,应用脉冲多普勒测量各组孕妇肾叶间动脉(IRA)收缩期血流峰值流速(PSV)、舒张末期血流流速(EDV)、加速时间(AT)、阻力指数(RI)、PSV/EDV (S/D).结果:治疗前组PSV (28.72±1.21) m/s、EDV (6.78±2.13)m/s明显低于对照组和治疗后组;RI (0.75±0.05),AT (0.10±0.04)s,S/D(3.76±0.22)明显高于对照组和治疗后组,差异有统计学意义(P< 0.05).结论:多普勒超声检查评价重度子痫前期孕妇药物治疗前后肾动脉血流参数变化,重复性强,为临床诊断和治疗重度子痫提供了重要的依据,具有较高的临床应用价值.%Objective: To investigate the characteristics of the parameter changes of renal artery blood flow before and after drug treatment in pregnancy-induced hypertension and severe eclampsism pregnant women by color doppler ultrasonography, and evaluate its clinical application value. Methods: 100 normal pregnant women were selected as the control group. 30 cases of severe eclampsism pregnant women were selected as pretherapy group. The same 30 women in pretherapy group after medical treatment were taken as post-treatment group. Ultrasonography studies were performed with Acuson Sequoia 512 and ALOKA a5 equipment, probe frequency 3.5-5.0 MHz. Observed the inner structures of kidneys of all gravida. Measured the peak systolic velocity (PSV), end diastolic velocity (EDV), acceleration time (AT), resistance index (RI), peak systolic velocity and end-diastolic maximum velocity ratio (S/D) of interlobar renal artery (IRA) of all

  6. 肾血流彩色多普勒检测与骨形态发生蛋白-7检测在2型糖尿病肾病早期诊断中的价值%Evaluation of color Doppler ultrasound of renal blood flow combined with the detection of bone morphogenetic protein-7 in early diagnosis of type 2 diabetic nephropathy

    张之杰; 于宁; 王正滨; 闫志梅; 孟冬梅; 刘荣桂; 丁兆艳; 史锋锋


    目的 探讨彩色多普勒超声检查肾血流与骨形态发生蛋白-7(BMP-7)水平检测在2型糖尿病肾病中的诊断价值.方法 检测90例糖尿病肾病患者与30例健康志愿者血BMP-7水平,并经彩色多普勒超声测量肾血流动力学参数,比较各组血BMP-7水平、肾段动脉及肾叶间动脉阻力指数(RI).结果 与对照组比较,随着糖尿病肾损害程度加重,BMP-7水平逐渐降低(P<0.01),肾段动脉、肾叶间动脉收缩期最大血流速度及舒张末期最低血流速度逐渐减慢,RI增高(P<0.01).BMP-7水平与肾段动脉、叶间动脉RI间存在显著负相关(r=-0.603,P<0.01;r=-0.652,P<0.01).结论 彩色多普勒超声测量肾血流动力学参数联合检测血BMP-7水平对早期预测糖尿病肾病的肾损害程度有重要价值.%Objective To evaluate the significance of color Doppler ultrasound examination of renal blood flow combined with the detection of bone morphogenetic protein-7(BMP-7)in early diagnosis of type 2 diabetic nephropathy.Methods Blood BMP-7 level was tested in 90 patients with type 2 diabetic nephropathy and 30 controls,and parameters of renal blood flow were measured by color Doppler ultrasound examination.Blood BMP-7 level as well as resistant index(RI)of segmental renal artery(SRA)and interlobar renal artery(IRA),were compared between these two groups.Results Compared with controls,blood BMP-7 level gradually decreased with the aggravation of diabetic kidney damage(P<0.01).The peak systolic velocity(Vmax)and the end diastolic velocity(Vmin)of SRA and TRA were slowed gradually,while RI increased(P<0.01).Blood BMP-7 level was negatively correlated with IRA's and SRA's RI of IRA and SRA(r =-0.603,P<0.01;r =-0.652,P<0.01).Conclusions Color Doppler ultrasound examination of renal blood flow combined with detection of BMP-7 might play an important role in early diagnosis of type 2 diabetic nephropathy.

  7. Design of pulse waveform for waveform division multiple access UWB wireless communication system.

    Yin, Zhendong; Wang, Zhirui; Liu, Xiaohui; Wu, Zhilu


    A new multiple access scheme, Waveform Division Multiple Access (WDMA) based on the orthogonal wavelet function, is presented. After studying the correlation properties of different categories of single wavelet functions, the one with the best correlation property will be chosen as the foundation for combined waveform. In the communication system, each user is assigned to different combined orthogonal waveform. Demonstrated by simulation, combined waveform is more suitable than single wavelet function to be a communication medium in WDMA system. Due to the excellent orthogonality, the bit error rate (BER) of multiuser with combined waveforms is so close to that of single user in a synchronous system. That is to say, the multiple access interference (MAI) is almost eliminated. Furthermore, even in an asynchronous system without multiuser detection after matched filters, the result is still pretty ideal and satisfactory by using the third combination mode that will be mentioned in the study.

  8. WFCatalog: A catalogue for seismological waveform data

    Trani, Luca; Koymans, Mathijs; Atkinson, Malcolm; Sleeman, Reinoud; Filgueira, Rosa


    This paper reports advances in seismic waveform description and discovery leading to a new seismological service and presents the key steps in its design, implementation and adoption. This service, named WFCatalog, which stands for waveform catalogue, accommodates features of seismological waveform data. Therefore, it meets the need for seismologists to be able to select waveform data based on seismic waveform features as well as sensor geolocations and temporal specifications. We describe the collaborative design methods and the technical solution showing the central role of seismic feature catalogues in framing the technical and operational delivery of the new service. Also, we provide an overview of the complex environment wherein this endeavour is scoped and the related challenges discussed. As multi-disciplinary, multi-organisational and global collaboration is necessary to address today's challenges, canonical representations can provide a focus for collaboration and conceptual tools for agreeing directions. Such collaborations can be fostered and formalised by rallying intellectual effort into the design of novel scientific catalogues and the services that support them. This work offers an example of the benefits generated by involving cross-disciplinary skills (e.g. data and domain expertise) from the early stages of design, and by sustaining the engagement with the target community throughout the delivery and deployment process.

  9. SCA Waveform Development for Space Telemetry

    Mortensen, Dale J.; Kifle, Multi; Hall, C. Steve; Quinn, Todd M.


    The NASA Glenn Research Center is investigating and developing suitable reconfigurable radio architectures for future NASA missions. This effort is examining software-based open-architectures for space based transceivers, as well as common hardware platform architectures. The Joint Tactical Radio System's (JTRS) Software Communications Architecture (SCA) is a candidate for the software approach, but may need modifications or adaptations for use in space. An in-house SCA compliant waveform development focuses on increasing understanding of software defined radio architectures and more specifically the JTRS SCA. Space requirements put a premium on size, mass, and power. This waveform development effort is key to evaluating tradeoffs with the SCA for space applications. Existing NASA telemetry links, as well as Space Exploration Initiative scenarios, are the basis for defining the waveform requirements. Modeling and simulations are being developed to determine signal processing requirements associated with a waveform and a mission-specific computational burden. Implementation of the waveform on a laboratory software defined radio platform is proceeding in an iterative fashion. Parallel top-down and bottom-up design approaches are employed.

  10. Renal perfusion scintiscan

    Renal perfusion scintigraphy; Radionuclide renal perfusion scan; Perfusion scintiscan - renal; Scintiscan - renal perfusion ... supply the kidneys. This is a condition called renal artery stenosis. Significant renal artery stenosis may be ...

  11. Laser Doppler Imaging of Microflow

    Gross, Michel; Leng, Jacques


    We report a pilot study with a wide-field laser Doppler detection scheme used to perform laser Doppler anemometry and imaging of particle seeded microflow. The optical field carrying the local scatterers (particles) dynamic state, as a consequence of momentum transfer at each scattering event, is analyzed in the temporal frequencies domain. The setup is based on heterodyne digital holography, which is used to map the scattered field in the object plane at a tunable frequency with a multipixel detector. We show that wide-field heterodyne laser Doppler imaging can be used for quantitative microflow diagnosis; in the presented study, maps of the first-order moment of the Doppler frequency shift are used as a quantitative and directional estimator of the Doppler signature of particles velocity.

  12. Photonic arbitrary waveform generator based on Taylor synthesis method

    Liao, Shasha; Ding, Yunhong; Dong, Jianji


    Arbitrary waveform generation has been widely used in optical communication, radar system and many other applications. We propose and experimentally demonstrate a silicon-on-insulator (SOI) on chip optical arbitrary waveform generator, which is based on Taylor synthesis method. In our scheme......, a Gaussian pulse is launched to some cascaded microrings to obtain first-, second- and third-order differentiations. By controlling amplitude and phase of the initial pulse and successive differentiations, we can realize an arbitrary waveform generator according to Taylor expansion. We obtain several typical...... waveforms such as square waveform, triangular waveform, flat-top waveform, sawtooth waveform, Gaussian waveform and so on. Unlike other schemes based on Fourier synthesis or frequency-to-time mapping, our scheme is based on Taylor synthesis method. Our scheme does not require any spectral disperser or large...

  13. Photonic arbitrary waveform generator based on Taylor synthesis method.

    Liao, Shasha; Ding, Yunhong; Dong, Jianji; Yan, Siqi; Wang, Xu; Zhang, Xinliang


    Arbitrary waveform generation has been widely used in optical communication, radar system and many other applications. We propose and experimentally demonstrate a silicon-on-insulator (SOI) on chip optical arbitrary waveform generator, which is based on Taylor synthesis method. In our scheme, a Gaussian pulse is launched to some cascaded microrings to obtain first-, second- and third-order differentiations. By controlling amplitude and phase of the initial pulse and successive differentiations, we can realize an arbitrary waveform generator according to Taylor expansion. We obtain several typical waveforms such as square waveform, triangular waveform, flat-top waveform, sawtooth waveform, Gaussian waveform and so on. Unlike other schemes based on Fourier synthesis or frequency-to-time mapping, our scheme is based on Taylor synthesis method. Our scheme does not require any spectral disperser or large dispersion, which are difficult to fabricate on chip. Our scheme is compact and capable for integration with electronics.

  14. Krylov subspace acceleration of waveform relaxation

    Lumsdaine, A.; Wu, Deyun [Univ. of Notre Dame, IN (United States)


    Standard solution methods for numerically solving time-dependent problems typically begin by discretizing the problem on a uniform time grid and then sequentially solving for successive time points. The initial time discretization imposes a serialization to the solution process and limits parallel speedup to the speedup available from parallelizing the problem at any given time point. This bottleneck can be circumvented by the use of waveform methods in which multiple time-points of the different components of the solution are computed independently. With the waveform approach, a problem is first spatially decomposed and distributed among the processors of a parallel machine. Each processor then solves its own time-dependent subsystem over the entire interval of interest using previous iterates from other processors as inputs. Synchronization and communication between processors take place infrequently, and communication consists of large packets of information - discretized functions of time (i.e., waveforms).

  15. Wavelet analysis of the impedance cardiogram waveforms

    Podtaev, S.; Stepanov, R.; Dumler, A.; Chugainov, S.; Tziberkin, K.


    Impedance cardiography has been used for diagnosing atrial and ventricular dysfunctions, valve disorders, aortic stenosis, and vascular diseases. Almost all the applications of impedance cardiography require determination of some of the characteristic points of the ICG waveform. The ICG waveform has a set of characteristic points known as A, B, E ((dZ/dt)max) X, Y, O and Z. These points are related to distinct physiological events in the cardiac cycle. Objective of this work is an approbation of a new method of processing and interpretation of the impedance cardiogram waveforms using wavelet analysis. A method of computer thoracic tetrapolar polyrheocardiography is used for hemodynamic registrations. Use of original wavelet differentiation algorithm allows combining filtration and calculation of the derivatives of rheocardiogram. The proposed approach can be used in clinical practice for early diagnostics of cardiovascular system remodelling in the course of different pathologies.

  16. Waveform information from quantum mechanical entropy

    Funkhouser, Scott; Suski, William; Winn, Andrew


    Although the entropy of a given signal-type waveform is technically zero, it is nonetheless desirable to use entropic measures to quantify the associated information. Several such prescriptions have been advanced in the literature but none are generally successful. Here, we report that the Fourier-conjugated `total entropy' associated with quantum-mechanical probabilistic amplitude functions (PAFs) is a meaningful measure of information in non-probabilistic real waveforms, with either the waveform itself or its (normalized) analytic representation acting in the role of the PAF. Detailed numerical calculations are presented for both adaptations, showing the expected informatic behaviours in a variety of rudimentary scenarios. Particularly noteworthy are the sensitivity to the degree of randomness in a sequence of pulses and potential for detection of weak signals.

  17. Waveform Design for Wireless Power Transfer

    Clerckx, Bruno; Bayguzina, Ekaterina


    Far-field Wireless Power Transfer (WPT) has attracted significant attention in recent years. Despite the rapid progress, the emphasis of the research community in the last decade has remained largely concentrated on improving the design of energy harvester (so-called rectenna) and has left aside the effect of transmitter design. In this paper, we study the design of transmit waveform so as to enhance the DC power at the output of the rectenna. We derive a tractable model of the non-linearity of the rectenna and compare with a linear model conventionally used in the literature. We then use those models to design novel multisine waveforms that are adaptive to the channel state information (CSI). Interestingly, while the linear model favours narrowband transmission with all the power allocated to a single frequency, the non-linear model favours a power allocation over multiple frequencies. Through realistic simulations, waveforms designed based on the non-linear model are shown to provide significant gains (in terms of harvested DC power) over those designed based on the linear model and over non-adaptive waveforms. We also compute analytically the theoretical scaling laws of the harvested energy for various waveforms as a function of the number of sinewaves and transmit antennas. Those scaling laws highlight the benefits of CSI knowledge at the transmitter in WPT and of a WPT design based on a non-linear rectenna model over a linear model. Results also motivate the study of a promising architecture relying on large-scale multisine multi-antenna waveforms for WPT. As a final note, results stress the importance of modeling and accounting for the non-linearity of the rectenna in any system design involving wireless power.

  18. Filter transient response to EEG waveforms.

    Shirakawa, S; Smith, J R; Azumi, K


    The response of two types of linear filters to sinusoidal bursts was calculated to demonstrate how filters can distort EEG waveforms. Results show that the wider the filter bandwidth the less is the distortion, and for a given bandwidth, the higher the filter order the greater the distortion. The response of a linear phase filter was also calculated to demonstrate that this type of filter can also cause waveform distortion, although it is normally less than that caused by Butterworth, Tchebychev and elliptic filters.

  19. High-Energy Optical Parametric Waveform Synthesizer

    Muecke, Oliver D.; Cirmi, G.; Fang, S.; Rossi, G. M.; Chia, Shih-Hsuan; Kärtner, F. X.; Manzoni, C.; Farinello, P.; Cerullo, and G.


    We discuss the ongoing development of a phase-stable, multi-mJ 3-channel parametric waveform synthesizer generating a 2-octave-wide spectrum (0.52-2.4μm). After two amplification stages, the combined >125-μJ output supports 1.9-fs waveforms. First preliminary FROG-characterization results of the second-stage outputs demonstrate the feasibility to recompress all three channels simultaneously close to the Fourier limit. Energy scaling to ~2 mJ is achieved after three amplification stages. The f...

  20. Principles of waveform diversity and design

    Wicks, Michael


    This is the first book to discuss current and future applications of waveform diversity and design in subjects such as radar and sonar, communications systems, passive sensing, and many other technologies. Waveform diversity allows researchers and system designers to optimize electromagnetic and acoustic systems for sensing, communications, electronic warfare or combinations thereof. This book enables solutions to problems, explaining how each system performs its own particular function, as well as how it is affected by other systems and how those other systems may likewise be affected. It is

  1. Signal processing in noise waveform radar

    Kulpa, Krzysztof


    This book is devoted to the emerging technology of noise waveform radar and its signal processing aspects. It is a new kind of radar, which use noise-like waveform to illuminate the target. The book includes an introduction to basic radar theory, starting from classical pulse radar, signal compression, and wave radar. The book then discusses the properties, difficulties and potential of noise radar systems, primarily for low-power and short-range civil applications. The contribution of modern signal processing techniques to making noise radar practical are emphasized, and application examples

  2. Fractal Dimension of Voice-Signal Waveforms


    The fractal dimension is one important parameter that characterizes waveforms. In this paper, we derive a new method to calculate fractal dimension of digital voice-signal waveforms. We show that fractal dimension is an efficient tool for speaker recognition or speech recognition. It can be used to identify different speakers or distinguish speech. We apply our results to Chinese speaker recognition and numerical experiment shows that fractal dimension is an efficient parameter to characterize individual Chinese speakers. We have developed a semiautomatic voiceprint analysis system based on the theory of this paper and former researches.

  3. Progression to calcific mitral stenosis in end-stage renal disease.

    D'Cruz, I A; Madu, E C


    A 59-year-old man with end-stage renal disease and on hemodialysis had neither mitral stenosis nor mitral calcification on echo-Doppler examination in 1989, but had extensive mitral calcification and definite mitral stenosis on conventional and transesophageal echocardiography in 1994. The left ventricle had marked concentric hypertrophy. To our knowledge this is the first documentation of the development of calcific mitral stenosis in end-stage renal disease revealed by serial echo-Doppler studies.

  4. Applications of Doppler optical coherence tomography

    Xu, Zhiqiang

    longitudinal resolution and the imaging depth for OCT imaging. Doppler OCT is becoming an increasingly popular field of investigation within optical coherence tomography with potentially important applications in cardiovascular and microfluidic research. We have spent some of the effort on searching for accurate and efficient methods for processing the experimental data. We applied the pseudo Wigner time-frequency distribution method to the data processing of Doppler OCT and compared its performance to that of the short-time Fourier transform method, the Hilbert-based phase-resolved method and the autocorrelation method. We concluded that the pseudo Wigner-distribution signal processing method is overall more precise than other often-used methods in Doppler OCT for the analysis of cross-sectional velocity distributions, especially in the high velocity regime. We also discovered the advantage of using the time-domain instead of the frequency domain for Doppler OCT for some applications where precise Doppler-speed metrology is essential. Based on the fact that the obtained local OCT interference signal is almost a single periodic waveform, we have developed a novel, simple and less time-consuming processing method based on the zero-crossing points in an OCT signal for the measurement of the Doppler frequency in a laminar flow. This method was compared to other processing approaches currently used in Doppler OCT. The results show that in the case of laminar flow, the zero-crossing method gives the more precise results, especially in the higher velocity regime with a substantial economy in processing time and an increase in dynamic range which can reach 70 dB. This feature becomes a major advantage in metrology if one wants to measure velocities over several orders of magnitude. We have applied this technique to some real flow models and the preliminary results on flow velocity distributions obtained in the case of a microfluidic circuit and in that of a phantom of a blood vessel

  5. Uterine artery flow velocity waveforms during uterine contractions: differences between oxytocin-induced contractions and spontaneous labor contractions.

    Tahara, Mie; Nakai, Yuichiro; Yasui, Tomoyo; Nishimoto, Sachiyo; Nakano, Akemi; Matsumoto, Makiko; Nobeyama, Hiroyuki; Nishihara, Rika; Iwanaga, Naoko; Ishiko, Osamu


    To clarify the effects on uterine arterial flow velocity waveforms of uterine contractions following oxytocin infusion and during spontaneous labor. Uterine arterial flow velocity waveforms were obtained by pulsed Doppler methods from 22 women during an oxytocin challenge test (OCT), 26 women during oxytocin-induced labor, and 40 women during spontaneous labor. Mean resistance index (RI) for bilateral arteries was used for analyses. After the onset of labor, flow velocity waveforms were assessed according to cervical dilatation. During OCT, Doppler flow velocimetry was performed when three uterine contractions occurred per 10-min period. RI values did not differ significantly between induced and spontaneous labor during relaxations at any level of cervical dilatation. However, during contractions, RI was significantly higher for induced labor than for spontaneous labor. Absence or reversal of flow was more frequent in the OCT group than in the induced labor group (P labor groups. Interactions between the contracting uterine body and the relaxing lower segment in oxytocin-induced labor might be associated with differences in uterine arterial flow during contraction between oxytocin-induced and spontaneous labor. However, changes in the intensity of uterine contractions during labor progression might differ between oxytocin-induced and spontaneous labor.

  6. Successful angioplasty during pregnancy for renal artery stenosis.

    Margueritte, François; Velasco, Stephane; Pourrat, Olivier; Pierre, Fabrice


    Renal artery stenosis can be diagnosed during pregnancy and treated at the same time. A 30-year-old woman had a sudden, severe but asymptomatic hypertensive crisis at 21 weeks of gestation. The diagnosis of renal artery stenosis suspected on Doppler ultrasonography was confirmed and treated by renal angioplasty, which reduced her blood pressure. At 27 weeks of gestation, her blood pressure increased again, associated with significant proteinuria, suggesting pre-eclampsia. A cesarean section was performed giving birth to a healthy 940-g child. Renal artery stenosis should be considered when sudden and early-onset hypertension appears during pregnancy.

  7. A New Method of Designing Waveform Codebook


    The codebook search takes much operation quantity in CELP coder. The paper puts forward a new method redesigning the waveform codebook known, and lists the experimental data. It has been proved that the operation complexity and transmission bit rate were decreased by using the new codebook, and the synthesis speech quality was high.

  8. Waveform Selectivity at the Same Frequency

    Wakatsuchi, Hiroki; Anzai, Daisuke; Rushton, Jeremiah J.; Gao, Fei; Kim, Sanghoon; Sievenpiper, Daniel F.


    Electromagnetic properties depend on the composition of materials, i.e. either angstrom scales of molecules or, for metamaterials, subwavelength periodic structures. Each material behaves differently in accordance with the frequency of an incoming electromagnetic wave due to the frequency dispersion or the resonance of the periodic structures. This indicates that if the frequency is fixed, the material always responds in the same manner unless it has nonlinearity. However, such nonlinearity is controlled by the magnitude of the incoming wave or other bias. Therefore, it is difficult to distinguish different incoming waves at the same frequency. Here we present a new concept of circuit-based metasurfaces to selectively absorb or transmit specific types of waveforms even at the same frequency. The metasurfaces, integrated with schottky diodes as well as either capacitors or inductors, selectively absorb short or long pulses, respectively. The two types of circuit elements are then combined to absorb or transmit specific waveforms in between. This waveform selectivity gives us another degree of freedom to control electromagnetic waves in various fields including wireless communications, as our simulation reveals that the metasurfaces are capable of varying bit error rates in response to different waveforms. PMID:25866071

  9. Windowing Waveform Relaxation of Initial Value Problems

    Yao-lin Jiang


    We present a windowing technique of waveform relaxation for dynamic systems. An effective estimation on window length is derived by an iterative error expression provided here. Relaxation processes can be speeded up if one takes the windowing technique in advance. Numerical experiments are given to further illustrate the theoretical analysis.

  10. Resolution analysis in full waveform inversion

    Fichtner, A.; Trampert, J.


    We propose a new method for the quantitative resolution analysis in full seismic waveform inversion that overcomes the limitations of classical synthetic inversions while being computationally more efficient and applicable to any misfit measure. The method rests on (1) the local quadratic approximat

  11. Seismic Waveform Inversion by Stochastic Optimization

    Tristan van Leeuwen


    Full Text Available We explore the use of stochastic optimization methods for seismic waveform inversion. The basic principle of such methods is to randomly draw a batch of realizations of a given misfit function and goes back to the 1950s. The ultimate goal of such an approach is to dramatically reduce the computational cost involved in evaluating the misfit. Following earlier work, we introduce the stochasticity in waveform inversion problem in a rigorous way via a technique called randomized trace estimation. We then review theoretical results that underlie recent developments in the use of stochastic methods for waveform inversion. We present numerical experiments to illustrate the behavior of different types of stochastic optimization methods and investigate the sensitivity to the batch size and the noise level in the data. We find that it is possible to reproduce results that are qualitatively similar to the solution of the full problem with modest batch sizes, even on noisy data. Each iteration of the corresponding stochastic methods requires an order of magnitude fewer PDE solves than a comparable deterministic method applied to the full problem, which may lead to an order of magnitude speedup for waveform inversion in practice.

  12. Analog circuit design designing waveform processing circuits

    Feucht, Dennis


    The fourth volume in the set Designing Waveform-Processing Circuits builds on the previous 3 volumes and presents a variety of analog non-amplifier circuits, including voltage references, current sources, filters, hysteresis switches and oscilloscope trigger and sweep circuitry, function generation, absolute-value circuits, and peak detectors.

  13. Processing Waveforms as Trees for Pattern Recognition.


    patterns (after Ganong (15]) 5.7 ECG Classification As in the previous example, waveforms were simulated with additive colored gaussian noise. In order to...Principles and Techniques- (AAPG Course Note Series 13), Amer. Assoc. Pet. Geol., Tulsa, OK,p. 86, (1984). [15] W. F. Ganong , Review of Medical Physiology. Lange, Los Altos, CA. pp. 393-408, (1973). /


    A. V. Govorov


    Full Text Available Renal cryoablation is an alternative minimally-invasive method of treatment for localized renal cell carcinoma. The main advantages of this methodology include visualization of the tumor and the forming of "ice ball" in real time, fewer complications compared with other methods of treatment of renal cell carcinoma, as well as the possibility of conducting cryotherapy in patients with concomitant pathology. Compared with other ablative technologies cryoablation has a low rate of repeat sessions and good intermediate oncological results. The studies of long-term oncological and functional results of renal cryoablation are presently under way.

  15. Renal angiomyolipoma

    Holm-Nielsen, P; Sørensen, Flemming Brandt


    lesion. Three cases of renal angiomyolipoma, 2 of which underwent perfusion-fixation, were studied by electron microscopy to clarify the cellular composition of this lesion. In the smooth muscle cells abundant accumulation of glycogen was found, whereas the lipocytes disclosed normal ultrastructural......-specific vesicular structures. These findings suggest a secondary vascular damage, i.e. the thickened vessels may not be a primary, integral part of renal angiomyolipoma. Evidence of a common precursor cell of renal angiomyolipoma was not disclosed. It is concluded that renal angiomyolipoma is a hamartoma composed...

  16. Mechanisms of K(+) induced renal vasodilation in normo- and hypertensive rats in vivo

    Magnusson, Linda Helena Margaretha; Sørensen, Charlotte Mehlin; Braunstein, T H;


    Aim: We investigated the mechanisms behind K(+) -induced renal vasodilation in vivo in normotensive Sprague-Dawley (SD) rats and spontaneously hypertensive rats (SHR). Methods: Renal blood flow (RBF) was measured utilizing an ultrasonic Doppler flow probe. Renal vascular resistance (RVR) was calc......Aim: We investigated the mechanisms behind K(+) -induced renal vasodilation in vivo in normotensive Sprague-Dawley (SD) rats and spontaneously hypertensive rats (SHR). Methods: Renal blood flow (RBF) was measured utilizing an ultrasonic Doppler flow probe. Renal vascular resistance (RVR......) was calculated as the ratio of mean arterial pressure (MAP) and RBF (RVR = MAP/RBF). Test drugs were introduced directly into the renal artery. Inward rectifier K(+) (K(ir) ) channels and Na(+) ,K(+) -ATPase were blocked by Ba(2+) and ouabain (estimated plasma concentrations ~20 and ~7 µm) respectively. Results...

  17. Study on simulation and experiment of laser micro-Doppler effect for detecting complex vibration

    Yuan, Shuai; Zhang, Juan; Liu, Mei-juan; Zhang, Jun


    The spectrum of radar signal will be modulated by moving target or vibration and turning part of the target, this is called micro-Doppler effect. It is a new way of using micro-Doppler effect to realize the feature extraction and target recognition. Because the complex vibration target has more complicated frequency component than the single frequency target, so it is very useful to do the research of simulation and experiment of laser micro-Doppler effect for detecting complex vibration. In this paper, the research on simulation and experiment of laser micro-Doppler effect for detecting complex vibration of moving target was developed based on the simulation research of micro-Doppler effect in lidar. Firstly, the geometry of complex vibrating target detection in radar was established. Secondly, the simulation and experiment signal sources were compared and also the returned signals in radar of the simulation and experiment were compared, the compared results showed that the two complex signal sources were very similar, and the frequency change trend of returned signals in radar was the same. Thirdly, joint time-frequency analysis method of the reassigned smoothed pseudo Wigner-Ville distribution (RSPWVD) was introduced to analyze the signals. The results showed that in RSPWVD, the waveform of the vibration target, the target vibration period, the Doppler frequency shift and the target's speed can be got. The simulation results and the experiment results got by the RSPWVD had the basically same frequency characteristics. So the RSPWVD can reflect very well the micro-Doppler characteristics of moving target's complex vibration. In conclusion it proved the validity of the simulated model, also it proved that using this time-frequency method to analyze the micro-Doppler signal of complex vibration was correct. And it laid the foundation of further using lidar to realize the classification and identification of target.

  18. [Bilateral renal vein thrombosis and acute renal failure due to inferior vena cava filter thrombosis. Report of one case].

    Vega, Jorge; Díaz, Rienzi


    Bilateral renal vein thrombosis is an unusual etiology of acute renal failure and usually is associated with nephrotic syndrome. We report a 77-year-old man, consulting in the emergency room for anuria that appeared 24 hours after a syncope. The patient was carrier of an inferior vena cava filter prophylactically installed 17 months earlier and was not receiving anticoagulation. Serum creatinine on admission was 5.45 mg/dl and blood urea nitrogen was 54 mg/dl. Computed tomography and Doppler ultrasonography showed an extensive thrombosis of inferior vena cava and both renal veins. Heparin therapy was started with a rapid recovery of renal function and diuresis.

  19. Doppler characteristics of sea clutter.

    Raynal, Ann Marie; Doerry, Armin Walter


    Doppler radars can distinguish targets from clutter if the target's velocity along the radar line of sight is beyond that of the clutter. Some targets of interest may have a Doppler shift similar to that of clutter. The nature of sea clutter is different in the clutter and exo-clutter regions. This behavior requires special consideration regarding where a radar can expect to find sea-clutter returns in Doppler space and what detection algorithms are most appropriate to help mitigate false alarms and increase probability of detection of a target. This paper studies the existing state-of-the-art in the understanding of Doppler characteristics of sea clutter and scattering from the ocean to better understand the design and performance choices of a radar in differentiating targets from clutter under prevailing sea conditions.

  20. Dual-Doppler Feasibility Study

    Huddleston, Lisa L.


    When two or more Doppler weather radar systems are monitoring the same region, the Doppler velocities can be combined to form a three-dimensional (3-D) wind vector field thus providing for a more intuitive analysis of the wind field. A real-time display of the 3-D winds can assist forecasters in predicting the onset of convection and severe weather. The data can also be used to initialize local numerical weather prediction models. Two operational Doppler Radar systems are in the vicinity of Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS); these systems are operated by the 45th Space Wing (45 SW) and the National Weather Service Melbourne, Fla. (NWS MLB). Dual-Doppler applications were considered by the 45 SW in choosing the site for the new radar. Accordingly, the 45th Weather Squadron (45 WS), NWS MLB and the National Aeronautics and Space Administration tasked the Applied Meteorology Unit (AMU) to investigate the feasibility of establishing dual-Doppler capability using the two existing systems. This study investigated technical, hardware, and software requirements necessary to enable the establishment of a dual-Doppler capability. Review of the available literature pertaining to the dual-Doppler technique and consultation with experts revealed that the physical locations and resulting beam crossing angles of the 45 SW and NWS MLB radars make them ideally suited for a dual-Doppler capability. The dual-Doppler equations were derived to facilitate complete understanding of dual-Doppler synthesis; to determine the technical information requirements; and to determine the components of wind velocity from the equation of continuity and radial velocity data collected by the two Doppler radars. Analysis confirmed the suitability of the existing systems to provide the desired capability. In addition, it is possible that both 45 SW radar data and Terminal Doppler Weather Radar data from Orlando International Airport could be used to alleviate any

  1. Novel instantaneous laser Doppler velocimeter.

    Avidor, J M


    A laser Doppler velocimeter capable of directly measuring instantaneous velocities is described. The new LDV uses a novel detection technique based on the utilization of a static slightly defocused spherical Fabry-Perot interferometer used in conjunction with a special mask for the detection of instantaneous Doppler frequency shifts. The essential characteristics of this LDV are discussed, and such a system recently developed is described. Results of turbulent flow measurements show good agreement with data obtained using hot wire anemometry.

  2. Doppler ultrasound in kidney diseases: a key parameter in clinical long-term follow-up.

    Spatola, Leonardo; Andrulli, Simeone


    Doppler ultrasound has been extensively used in detecting reno-vascular diseases, showing to be a non-invasive, safe, low cost and repeatable tool. The Renal Resistive Index (RRI) [(peak systolic velocity - end diastolic velocity)/peak systolic velocity] is a semi-quantitative index derived by Doppler evaluation of renal vascular bed. Normally RRI is in the range of 0.47-0.70, it increases with aging and, usually, it shows a difference between the two kidneys less than 5-8 %. RRI is an important prognostic marker in chronic kidney diseases (CKD), both in diabetic and non-diabetic kidney diseases, because, in longitudinal prospective studies, it significantly correlated with hemodynamic (ABPM, SBP, DBP, pulse pressure) and histopathological parameters (glomerular sclerosis, arteriolosclerosis, interstitial fibrosis/tubular atrophy, interstitial infiltration). In acute kidney injury (AKI) RI is a valid tool in differentiating between pre-renal and renal failure and in predicting renal response to vaso-active agents. In addition a RRI >0.74 can predict the onset of AKI in septic patients. Renal Resistive Index is a useful marker in allograft diseases because it has been widely showed a correlation with histological lesions during worsening of renal function, both in acute rejection and in chronic allograft nephropathy. Recent studies suggest its role in the risk of new onset diabetes after transplantation and it could be one of the parameters to evaluate to shift or withdrawal immunological and/or hypertensive therapy.

  3. Renal cancer

    Corgna, Enrichetta; Betti, Maura; Gatta, Gemma; Roila, Fausto; De Mulder, Pieter H. M.


    In Europe, renal cancer (that is neoplasia of the kidney, renal pelvis or ureter (ICD-9 189 and ICD-10 C64-C66)) ranks as the seventh most common malignancy in men amongst whom there are 29,600 new cases each year (3.5% of all cancers). Tobacco, obesity and a diet poor in vegetables are all acknowle

  4. Renal fallure


    920705 Endothelin and acute renal failure:study on their relationship and possiblemechanisms. LIN Shanyan(林善锬), et al.Renal Res Lab, Huashan Hosp, Shanghai MedUniv, Shanghai, 200040. Natl Med J China 1992;72(4): 201-205. In order to investigate the role of endothelin

  5. Renal cancer.

    Corgna, E.; Betti, M.; Gatta, G.; Roila, F.; Mulder, P.H.M. de


    In Europe, renal cancer (that is neoplasia of the kidney, renal pelvis or ureter (ICD-9 189 and ICD-10 C64-C66)) ranks as the seventh most common malignancy in men amongst whom there are 29,600 new cases each year (3.5% of all cancers). Tobacco, obesity and a diet poor in vegetables are all

  6. Renal cancer

    Corgna, Enrichetta; Betti, Maura; Gatta, Gemma; Roila, Fausto; De Mulder, Pieter H. M.


    In Europe, renal cancer (that is neoplasia of the kidney, renal pelvis or ureter (ICD-9 189 and ICD-10 C64-C66)) ranks as the seventh most common malignancy in men amongst whom there are 29,600 new cases each year (3.5% of all cancers). Tobacco, obesity and a diet poor in vegetables are all

  7. Noninvasive calculation of the aortic blood pressure waveform from the flow velocity waveform: a proof of concept.

    Vennin, Samuel; Mayer, Alexia; Li, Ye; Fok, Henry; Clapp, Brian; Alastruey, Jordi; Chowienczyk, Phil


    Estimation of aortic and left ventricular (LV) pressure usually requires measurements that are difficult to acquire during the imaging required to obtain concurrent LV dimensions essential for determination of LV mechanical properties. We describe a novel method for deriving aortic pressure from the aortic flow velocity. The target pressure waveform is divided into an early systolic upstroke, determined by the water hammer equation, and a diastolic decay equal to that in the peripheral arterial tree, interposed by a late systolic portion described by a second-order polynomial constrained by conditions of continuity and conservation of mean arterial pressure. Pulse wave velocity (PWV, which can be obtained through imaging), mean arterial pressure, diastolic pressure, and diastolic decay are required inputs for the algorithm. The algorithm was tested using 1) pressure data derived theoretically from prespecified flow waveforms and properties of the arterial tree using a single-tube 1-D model of the arterial tree, and 2) experimental data acquired from a pressure/Doppler flow velocity transducer placed in the ascending aorta in 18 patients (mean ± SD: age 63 ± 11 yr, aortic BP 136 ± 23/73 ± 13 mmHg) at the time of cardiac catheterization. For experimental data, PWV was calculated from measured pressures/flows, and mean and diastolic pressures and diastolic decay were taken from measured pressure (i.e., were assumed to be known). Pressure reconstructed from measured flow agreed well with theoretical pressure: mean ± SD root mean square (RMS) error 0.7 ± 0.1 mmHg. Similarly, for experimental data, pressure reconstructed from measured flow agreed well with measured pressure (mean RMS error 2.4 ± 1.0 mmHg). First systolic shoulder and systolic peak pressures were also accurately rendered (mean ± SD difference 1.4 ± 2.0 mmHg for peak systolic pressure). This is the first noninvasive derivation of aortic pressure based on fluid dynamics (flow and wave speed) in the

  8. Aortic isthmus Doppler velocimetry: role in assessment of preterm fetal growth restriction.

    Kennelly, M M


    Intrauterine fetal growth restriction (IUGR) is an important pregnancy complication associated with significant adverse clinical outcome, stillbirth, perinatal morbidity and cerebral palsy. To date, no uniformly accepted management protocol of Doppler surveillance that reduces mortality and cognitive morbidity has emerged. Aortic isthmus (AoI) evaluation has been proposed as a potential monitoring tool for IUGR fetuses. In this review, the current knowledge of the relationship between AoI Doppler velocimetry and preterm fetal growth restriction is reviewed. Relevant technical aspects and reproducibility data are reviewed as we discuss AoI Doppler and its place within the existing repertoire of Doppler assessments in placental insufficiency. The AoI is a link between the right and left ventricles which perfuse the lower and upper body, respectively. The clinical use of AoI waveforms for monitoring fetal deterioration in IUGR has been limited, but preliminary work suggests that abnormal AoI impedance indices are an intermediate step between placental insufficiency-hypoxemia and cardiac decompensation. Further prospective studies correlating AoI indices with arterial and venous Doppler indices and perinatal outcome are required before encorporating this index into clinical practice.

  9. Renal Doppler Indices in Children with Nephrotic Syndrome ...


    The aetiological classes include idiopathic or primary, congenital and secondary .... control) was recruited until the minimum sample size was attained. Ultrasound ..... A similar study from Taiwan among adolescents and young adults is in ...

  10. Application of arbitrary waveform generator for noise radar

    Lukin, Konstantin A.; Zemlyaniy, Oleg V.; Vyplavin, Pavlo L.; Palamarchuk, Volodymyr P.


    The approach, when the waveforms of different types are exploited in the same radar (waveform diversity) requires new-generation sources of initial signals. For generating of different types of waveforms in the same radar we suggest using Arbitrary Waveform Generator, that allows output any type of pre-programmed signal in real time. We have carried out preliminary experimental tests of the stepped-delay mode of UHF-band radar evaluation kit. The series of experimental testing shows efficiency AWG application in radar with variety of sounding waveforms.

  11. Estimation of central aortic pressure waveform features derived from the brachial cuff volume displacement waveform.

    Butlin, Mark; Qasem, Ahmad; Avolio, Alberto P


    There is increasing interest in non-invasive estimation of central aortic waveform parameters in the clinical setting. However, controversy has arisen around radial tonometric based systems due to the requirement of a trained operator or lack of ease of use, especially in the clinical environment. A recently developed device utilizes a novel algorithm for brachial cuff based assessment of aortic pressure values and waveform (SphygmoCor XCEL, AtCor Medical). The cuff was inflated to 10 mmHg below an individual's diastolic blood pressure and the brachial volume displacement waveform recorded. The aortic waveform was derived using proprietary digital signal processing and transfer function applied to the recorded waveform. The aortic waveform was also estimated using a validated technique (radial tonometry based assessment, SphygmoCor, AtCor Medical). Measurements were taken in triplicate with each device in 30 people (17 female) aged 22 to 79 years of age. An average for each device for each individual was calculated, and the results from the two devices were compared using regression and Bland-Altman analysis. A high correlation was found between the devices for measures of aortic systolic (R(2)=0.99) and diastolic (R(2)=0.98) pressure. Augmentation index and subendocardial viability ratio both had a between device R(2) value of 0.82. The difference between devices for measured aortic systolic pressure was 0.5±1.8 mmHg, and for augmentation index, 1.8±7.0%. The brachial cuff based approach, with an individualized sub-diastolic cuff pressure, provides an operator independent method of assessing not only systolic pressure, but also aortic waveform features, comparable to existing validated tonometric-based methods.

  12. Programmable Clock Waveform Generation for CCD Readout

    Vicente, J. de; Castilla, J.; Martinez, G.; Marin, J.


    Charge transfer efficiency in CCDs is closely related to the clock waveform. In this paper, an experimental framework to explore different FPGA based clock waveform generator designs is described. Two alternative design approaches for controlling the rise/fall edge times and pulse width of the CCD clock signal have been implemented: level-control and time-control. Both approaches provide similar characteristics regarding the edge linearity and noise. Nevertheless, dissimilarities have been found with respect to the area and frequency range of application. Thus, while the time-control approach consumes less area, the level control approach provides a wider range of clock frequencies since it does not suffer capacitor discharge effect. (Author) 8 refs.

  13. LISA parameter estimation using numerical merger waveforms

    Thorpe, J I; McWilliams, S T; Kelly, B J; Fahey, R P; Arnaud, K; Baker, J G, E-mail: James.I.Thorpe@nasa.go [NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771 (United States)


    Recent advances in numerical relativity provide a detailed description of the waveforms of coalescing massive black hole binaries (MBHBs), expected to be the strongest detectable LISA sources. We present a preliminary study of LISA's sensitivity to MBHB parameters using a hybrid numerical/analytic waveform for equal-mass, non-spinning holes. The Synthetic LISA software package is used to simulate the instrument response, and the Fisher information matrix method is used to estimate errors in the parameters. Initial results indicate that inclusion of the merger signal can significantly improve the precision of some parameter estimates. For example, the median parameter errors for an ensemble of systems with total redshifted mass of 10{sup 6} M{sub o-dot} at a redshift of z approx 1 were found to decrease by a factor of slightly more than two for signals with merger as compared to signals truncated at the Schwarzchild ISCO.

  14. LISA parameter estimation using numerical merger waveforms

    Thorpe, J I; Kelly, B J; Fahey, R P; Arnaud, K; Baker, J G


    Recent advances in numerical relativity provide a detailed description of the waveforms of coalescing massive black hole binaries (MBHBs), expected to be the strongest detectable LISA sources. We present a preliminary study of LISA's sensitivity to MBHB parameters using a hybrid numerical/analytic waveform for equal-mass, non-spinning holes. The Synthetic LISA software package is used to simulate the instrument response and the Fisher information matrix method is used to estimate errors in the parameters. Initial results indicate that inclusion of the merger signal can significantly improve the precision of some parameter estimates. For example, the median parameter errors for an ensemble of systems with total redshifted mass of one million Solar masses at a redshift of one were found to decrease by a factor of slightly more than two for signals with merger as compared to signals truncated at the Schwarzchild ISCO.

  15. Comparing numerical and analytic approximate gravitational waveforms

    Afshari, Nousha; Lovelace, Geoffrey; SXS Collaboration


    A direct observation of gravitational waves will test Einstein's theory of general relativity under the most extreme conditions. The Laser Interferometer Gravitational-Wave Observatory, or LIGO, began searching for gravitational waves in September 2015 with three times the sensitivity of initial LIGO. To help Advanced LIGO detect as many gravitational waves as possible, a major research effort is underway to accurately predict the expected waves. In this poster, I will explore how the gravitational waveform produced by a long binary-black-hole inspiral, merger, and ringdown is affected by how fast the larger black hole spins. In particular, I will present results from simulations of merging black holes, completed using the Spectral Einstein Code (, including some new, long simulations designed to mimic black hole-neutron star mergers. I will present comparisons of the numerical waveforms with analytic approximations.

  16. Experimentally induced acute uric acid nephropathy in rabbits: Findings of high resolution gray scale and doppler ultrasonographies

    Yang, Ik; Chung, Soo Young; Lee, Kyung Won; Kim, Hong Dae; Ko, Eun Young; Won, Mi Sook; Noh, Jung Woo [Hallym University College of Medicine, Seoul (Korea, Republic of); Park, Moon Hyang [Hanyang University College of Medicine, Seoul (Korea, Republic of)


    To evaluate changes of the high-resolution (HR) gray scale and doppler ultrasonographic (US) characteristics of experimentally induced acute uric acid (UA) nephropathy in rabbits. Acute UA nephropathy was induced in ten rabbits using supersaturated lithium carbonate solution. The rabbits were divided in two groups. Group I consisted of five rabbits, and they were injected with a single dose of 150 ml of saturated UA over one hour. During tis period, serial US studies of the kidneys of these rabbits were performed every ten minutes. Group II consisted of the remaining five rabbits, and three injections of 50 ml of saturated UA solution were given on the first, fifth and eight day and follow-up was done upto twenty fifth day. Sequential HR and Doppler US, renal biopsy and blood sampling were performed on day 1, 5, 8, 21, and 25 in the group II rabbits. In group I, HR and Doppler US examination revealed the normal resistive index without significant abnormality. On the other hand, US studies of group II showed poor renal corticomedullary differentiation, decreased renal blood flow and elevated resistive index. There was statistically significant correlation among US findings, histologic characteristics and chemical index (BUN, creatinine) of renal function. In addition, sequentially increased size and volume of the kidney were noted in both groups. HR gray scale and doppler US characteristics of experimentally induced acute UA nephropathy in rabbits were similar to those of acute renal failure caused by other well-known causes.

  17. Advanced Waveform Simulation for Seismic Monitoring


    velocity model. The method separates the main arrivals of the regional waveform into 5 windows: Pnl (vertical and radial components), Rayleigh (vertical and...ranges out to 10°, including extensive observations of crustal thinning and thickening and various Pnl complexities. Broadband modeling in 1D, 2D...existing models perform in predicting the various regional phases, Rayleigh waves, Love waves, and Pnl waves. Previous events from this Basin-and-Range

  18. The European seismological waveform framework EIDA

    Trani, Luca; Koymans, Mathijs; Quinteros, Javier; Heinloo, Andres; Euchner, Fabian; Strollo, Angelo; Sleeman, Reinoud; Clinton, John; Stammler, Klaus; Danecek, Peter; Pedersen, Helle; Ionescu, Constantin; Pinar, Ali; Evangelidis, Christos


    The ORFEUS1 European Integrated Data Archive (EIDA2) federates (currently) 11 major European seismological data centres into a common organisational and operational framework which offers: (a) transparent and uniform access tools, advanced services and products for seismological waveform data; (b) a platform for establishing common policies for the curation of seismological waveform data and the description of waveform data by standardised quality metrics; (c) proper attribution and citation (e.g. data ownership). After its establishment in 2013, EIDA has been collecting and distributing seamlessly large amounts of seismological data and products to the research community and beyond. A major task of EIDA is the on-going improvement of the services, tools and products portfolio in order to meet the increasingly demanding users' requirements. At present EIDA is entering a new operational phase and will become the reference infrastructure for seismological waveform data in the pan-European infrastructure for solid-Earth science: EPOS (European Plate Observing System)3. The EIDA Next Generation developments, initiated within the H2020 project EPOS-IP, will provide a new infrastructure that will support the seismological and multidisciplinary EPOS community facilitating interoperability in a broader context. EIDA NG comprises a number of new services and products e.g.: Routing Service, Authentication Service, WFCatalog, Mediator, Station Book and more in the near future. In this contribution we present the current status of the EIDA NG developments and provide an overview of the usage of the new services and their impact on the user community. 1 2 3

  19. Waveforms Measured in Confined Thermobaric Explosion

    Reichenbach, H; Neuwald, P; Kuhl, A L


    Experiments with 1.5-g Shock-Dispersed-Fuel (SDF) charges have been conducted in six different chambers. Both flake Aluminum and TNT were used as the fuel. Static pressure gauges on the chamber wall were the main diagnostic. Waveforms for explosions in air were significantly larger than those in nitrogen - thereby demonstrating a strong thermobaric (combustion) effect. This effect increases as the confinement volume decreases and the mixture richness approaches 1.

  20. Full-waveform inversion: Filling the gaps

    Beydoun, Wafik B.


    After receiving an outstanding response to its inaugural workshop in 2013, SEG once again achieved great success with its 2015 SEG Middle East Workshop, “Full-waveform inversion: Filling the gaps,” which took place 30 March–1 April 2015 in Abu Dhabi, UAE. The workshop was organized by SEG, and its partner sponsors were Saudi Aramco (gold sponsor), ExxonMobil, and CGG. Read More:

  1. Forward and Backward Pressure Waveform Morphology in Hypertension

    Li, Ye; Gu, Haotian; Fok, Henry; Alastruey, Jordi


    We tested the hypothesis that increased pulse wave reflection and altered backward waveform morphology contribute to increased pulse pressure in subjects with higher pulse pressure compared with lower pulse pressure and to actions of vasoactive drugs to increase pulse pressure. We examined the relationship of backward to forward wave morphology in 158 subjects who were evaluated for hypertension (including some normotensive subjects) divided into 3 groups by central pulse pressure: group 1, 33±6.5 mm Hg; group 2, 45±4.1 mm Hg; and group 3, 64±12.9 mm Hg (means±SD) and in healthy normotensive subjects during administration of inotropic and vasomotor drugs. Aortic pressure and flow in the aortic root were estimated by carotid tonometry and Doppler sonography, respectively. Morphology of the backward wave relative to the forward wave was similar in subjects in the lowest and highest tertiles of pulse pressure. Similar results were seen with the inotropic, vasopressor and vasodilator drugs, dobutamine, norepinephrine, and phentolamine, with the backward wave maintaining a constant ratio to the forward wave. However, nitroglycerin, a drug with a specific action to dilate muscular conduit arteries, reduced the amplitude of the backward wave relative to the forward wave from 0.26±0.018 at baseline to 0.19±0.019 during nitroglycerin 30 μg/min IV (P<0.01). These results are best explained by an approximately constant amount of reflection of the forward wave from the peripheral vasculature. The amount of reflection can be modified by dilation of peripheral muscular conduit arteries but contributes little to increased pulse pressure in hypertension. PMID:27920128

  2. Sparse Frequency Waveform Design for Radar-Embedded Communication

    Chaoyun Mai


    Full Text Available According to the Tag application with function of covert communication, a method for sparse frequency waveform design based on radar-embedded communication is proposed. Firstly, sparse frequency waveforms are designed based on power spectral density fitting and quasi-Newton method. Secondly, the eigenvalue decomposition of the sparse frequency waveform sequence is used to get the dominant space. Finally the communication waveforms are designed through the projection of orthogonal pseudorandom vectors in the vertical subspace. Compared with the linear frequency modulation waveform, the sparse frequency waveform can further improve the bandwidth occupation of communication signals, thus achieving higher communication rate. A certain correlation exists between the reciprocally orthogonal communication signals samples and the sparse frequency waveform, which guarantees the low SER (signal error rate and LPI (low probability of intercept. The simulation results verify the effectiveness of this method.

  3. Time-dependent phase error correction using digital waveform synthesis

    Doerry, Armin W.; Buskirk, Stephen


    The various technologies presented herein relate to correcting a time-dependent phase error generated as part of the formation of a radar waveform. A waveform can be pre-distorted to facilitate correction of an error induced into the waveform by a downstream operation/component in a radar system. For example, amplifier power droop effect can engender a time-dependent phase error in a waveform as part of a radar signal generating operation. The error can be quantified and an according complimentary distortion can be applied to the waveform to facilitate negation of the error during the subsequent processing of the waveform. A time domain correction can be applied by a phase error correction look up table incorporated into a waveform phase generator.

  4. Continuous high PRF waveforms for challenging environments

    Jaroszewski, Steven; Corbeil, Allan; Ryland, Robert; Sobota, David


    Current airborne radar systems segment the available time-on-target during each beam dwell into multiple Coherent Processing Intervals (CPIs) in order to eliminate range eclipsing, solve for unambiguous range, and increase the detection performance against larger Radar Cross Section (RCS) targets. As a consequence, these radars do not realize the full Signal-to-Noise Ratio (SNR) increase and detection performance improvement that is possible. Continuous High Pulse Repetition Frequency (HPRF) waveforms and processing enables the coherent integration of all available radar data over the full time-on-target. This can greatly increase the SNR for air targets at long range and/or with weak radar returns and significantly improve the detection performance against such targets. TSC worked with its partner KeyW to implement a Continuous HPRF waveform in their Sahara radar testbed and obtained measured radar data on both a ground vehicle target and an airborne target of opportunity. This experimental data was processed by TSC to validate the expected benefits of Continuous HPRF waveforms.

  5. Binary Black Holes: Mergers, Dynamics, and Waveforms

    Centrella, Joan


    The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based interferometer LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, data analysis, and astrophysics.

  6. Full waveform inversion for ultrasonic flaw identification

    Seidl, Robert; Rank, Ernst


    Ultrasonic Nondestructive Testing is concerned with detecting flaws inside components without causing physical damage. It is possible to detect flaws using ultrasound measurements but usually no additional details about the flaw like position, dimension or orientation are available. The information about these details is hidden in the recorded experimental signals. The idea of full waveform inversion is to adapt the parameters of an initial simulation model of the undamaged specimen by minimizing the discrepancy between these simulated signals and experimentally measured signals of the flawed specimen. Flaws in the structure are characterized by a change or deterioration in the material properties. Commonly, full waveform inversion is mostly applied in seismology on a larger scale to infer mechanical properties of the earth. We propose to use acoustic full waveform inversion for structural parameters to visualize the interior of the component. The method is adapted to US NDT by combining multiple similar experiments on the test component as the typical small amount of sensors is not sufficient for a successful imaging. It is shown that the combination of simulations and multiple experiments can be used to detect flaws and their position, dimension and orientation in emulated simulation cases.

  7. The internist and the renal resistive index: truths and doubts.

    Boddi, Maria; Natucci, Fabrizia; Ciani, Elisa


    The renal resistive index (RRI) is measured by Doppler sonography in an intrarenal artery, and is the difference between the peak systolic and end-diastolic blood velocities divided by the peak systolic velocity. The RRI is used for the study of vascular and renal parenchymal renal abnormalities, but growing evidence indicates that it is also a dynamic marker of systemic vascular properties. Renal vascular resistance is only one of several renal (vascular compliance, interstitial and venous pressure), and extrarenal (heart rate, aortic stiffness, pulse pressure) determinants that combine to determine the RRI values, and not the most important one. RRI cannot always be considered a specific marker of renal disease. To summarize from the literature: (1) hydronephrosis, abdominal hypertension, renal vein thrombosis and acute kidney injury are all associated with an acute increase in interstitial and venous pressure that determine RRI values. In all these conditions, RRI is a reliable marker of the severity of renal damage. (2) The hemodynamic impact of renal artery stenosis can be assayed by the RRI decrease in the homolateral kidney by virtue of decreasing pulse pressure. However, renal diseases that often coexist, increase renal vascular stiffness and hide the hemodynamic effect of renal stenosis. (3) In transplant kidney and in chronic renal disease, high RRI values (>0.80) can independently predict renal and clinical outcomes, but systemic (pulse pressure) rather than renal hemodynamic determinants sustain the predictive role of RRI. (4) Higher RRI detects target renal organ damage in hypertension and diabetes when renal function is still preserved, as a marker of systemic atherosclerotic burden. Is this the fact? We attempt to answer.

  8. A new technique for assessing arterial pressure wave forms and central pressure with tissue Doppler

    Haluska, Brian A; Jeffriess, Leanne; Mottram, Phillip M; Carlier, Stephane G; Marwick, Thomas H


    Background Non-invasive assessment of arterial pressure wave forms using applanation tonometry of the radial or carotid arteries can be technically challenging and has not found wide clinical application. 2D imaging of the common carotid arteries is routinely used and we sought to determine whether arterial waveform measurements could be derived from tissue Doppler imaging (TDI) of the carotid artery. Methods We studied 91 subjects (52 men, age 52 ± 14 years) with and without cardiovascular disease. Tonometry was performed on the carotid artery simultaneously with pulsed wave Doppler of the LVOT and acquired digitally. Longitudinal 2D images of the common carotid artery with and without TDI were also acquired digitally and both TDI and tonometry were calibrated using mean and diastolic cuff pressure and analysed off line. Results Correlation between central pressure by TDI and tonometry was excellent for maximum pressure (r = 0.97, p < 0.0001). The mean differences between central pressures derived by TDI and tonometry were minimal (systolic 5.36 ± 5.5 mmHg; diastolic 1.2 ± 1.2 mmHg). Conclusion Imaging of the common carotid artery motion with tissue Doppler may permit acquisition of a waveform analogous to that from tonometry. This method may simplify estimation of central arterial pressure and calculation of total arterial compliance. PMID:17266772

  9. Renal teratogens.

    Morgan, Thomas M; Jones, Deborah P; Cooper, William O


    In utero exposure to certain drugs early in pregnancy may adversely affect nephrogenesis. Exposure to drugs later in pregnancy may affect the renin-angiotensin system, which could have an impact on fetal or neonatal renal function. Reduction in nephron number and renal function could have adverse consequences for the child several years later. Data are limited on the information needed to guide decisions for patients and providers regarding the use of certain drugs in pregnancy. The study of drug nephroteratogenicity has not been systematized, a large, standardized, global approach is needed to evaluate the renal risks of in utero drug exposures.

  10. Planetary Doppler Imaging

    Murphy, N.; Jefferies, S.; Hart, M.; Hubbard, W. B.; Showman, A. P.; Hernandez, G.; Rudd, L.


    Determining the internal structure of the solar system's gas and ice giant planets is key to understanding their formation and evolution (Hubbard et al., 1999, 2002, Guillot 2005), and in turn the formation and evolution of the solar system. While internal structure can be constrained theoretically, measurements of internal density distributions are needed to uncover the details of the deep interior where significant ambiguities exist. To date the interiors of giant planets have been probed by measuring gravitational moments using spacecraft passing close to, or in orbit around the planet. Gravity measurements are effective in determining structure in the outer envelope of a planet, and also probing dynamics (e.g. the Cassini and Juno missions), but are less effective in probing deep structure or the presence of discrete boundaries. A promising technique for overcoming this limitation is planetary seismology (analogous to helioseismology in the solar case), postulated by Vorontsov, 1976. Using trapped pressure waves to probe giant planet interiors allows insight into the density and temperature distribution (via the sound speed) down to the planetary core, and is also sensitive to sharp boundaries, for example at the molecular to metallic hydrogen transition or at the core-envelope interface. Detecting such boundaries is not only important in understanding the overall structure of the planet, but also has implications for our understanding of the basic properties of matter at extreme pressures. Recent Doppler measurements of Jupiter by Gaulme et al (2011) claimed a promising detection of trapped oscillations, while Hedman and Nicholson (2013) have shown that trapped waves in Saturn cause detectable perturbations in Saturn's C ring. Both these papers have fueled interest in using seismology as a tool for studying the solar system's giant planets. To fully exploit planetary seismology as a tool for understanding giant planet structure, measurements need to be made

  11. General principles of carotid Doppler ultrasonography

    Lee, Whal [Dept. of Radiology, Seoul National University College of Medicine, Seoul (Korea, Republic of)


    Carotid Doppler ultrasonography is a popular tool for evaluating atherosclerosis of the carotid artery. Its two-dimensional gray scale can be used for measuring the intima-media thickness, which is very good biomarker for atherosclerosis and can aid in plaque characterization. The plaque morphology is related to the risk of stroke. The ulceration of plaque is also known as one of the strong predictors of future embolic event risk. Color Doppler ultrasonography and pulse Doppler ultrasonography have been used for detecting carotid artery stenosis. Doppler ultrasonography has unique physical properties. The operator should be familiar with the physics and other parameters of Doppler ultrasonography to perform optimal Doppler ultrasonography studies.

  12. [Large artery wall properties in dialyse and renal transplant patients with normal blood pressure].

    Posadzy-Małaczyńska, Anna; Kosch, Marcus; Hausberg, Martin; Rahn, Karl H; Małaczyński, Paweł; Głuszek, Jerzy; Tykarski, Andrzej


    Structural and mechanical properties of the arterial wall are altered in patients with renal failure. Age and hypertension are known to affect the vessel wall structure. Aging process of arterial wall appears to be accelerated in patients with end-stage renal failure. The mechanisms responsible for reduced arterial compliance and distensibility in dialyse patients and renal transplant recipients without hypertension remain to be evaluated. 20 normotensive dialyse patients (D), 20 normotensive renal transplant recipients (T) and 20 healthy volunteers (N) matched for age, sex and blood pressure as controls were enrolled in to the study. Patients with cardiovascular risk factors and diabetes were excluded. The arterial blood pressure of all patients placed below 140/90 mmHg. The dialyse patients and renal transplant recipients were eligible for the study if the serum creatinine level was below 2 mg/dl. In all subjects, fasting concentrations of serum creatinine, total cholesterol, HDL-cholesterol, LDL-cholesterol, hemoglobin and glucose were determined at enrollment to the study. Long-term immunosuppression consisted of cyclosporine and prednisolone. Blood pressure was measured using an automatic sphygmomanometer (Criticon Dinamap model 1846 SX). Pulse wave velocity (PWV) was evaluated using non-invasive automatic Complior device. The vessel wall properties of the left common carotid artery were studied using multigate pulsed Doppler's system (Pie Medical Equipment BV Maastricht, The Netherlands). The frequency of transducer used was 7.5 MHz. With this non-invasive method, the end-diastolic diameter (d) and the systolic increase of vessel diameter (distension delta d) were measured using ECG trigger. From these data relative systolic increase of vessel diameter (delta d/d) and arterial wall distensibility coefficient (DC) were calculated. Simultaneously with the ultrasound measurements at the left common carotid artery carotid pulse waveforms are recorded using

  13. The Waveform Server: A Web-based Interactive Seismic Waveform Interface

    Newman, R. L.; Clemesha, A.; Lindquist, K. G.; Reyes, J.; Steidl, J. H.; Vernon, F. L.


    Seismic waveform data has traditionally been displayed on machines that are either local area networked to, or directly host, a seismic networks waveform database(s). Typical seismic data warehouses allow online users to query and download data collected from regional networks passively, without the scientist directly visually assessing data coverage and/or quality. Using a suite of web-based protocols, we have developed an online seismic waveform interface that directly queries and displays data from a relational database through a web-browser. Using the Python interface to Datascope and the Python-based Twisted network package on the server side, and the jQuery Javascript framework on the client side to send and receive asynchronous waveform queries, we display broadband seismic data using the HTML Canvas element that is globally accessible by anyone using a modern web-browser. The system is used to display data from the USArray experiment, a US continent-wide migratory transportable seismic array. We are currently creating additional interface tools to create a rich-client interface for accessing and displaying seismic data that can be deployed to any system running Boulder Real Time Technology's (BRTT) Antelope Real Time System (ARTS). The software is freely available from the Antelope contributed code Git repository. Screenshot of the web-based waveform server interface

  14. Processing Aftershock Sequences Using Waveform Correlation

    Resor, M. E.; Procopio, M. J.; Young, C. J.; Carr, D. B.


    For most event monitoring systems, the objective is to keep up with the flow of incoming data, producing a bulletin with some modest, relatively constant, time delay after present time, often a period of a few hours or less. Because the association problem scales exponentially and not linearly with the number of detections, a dramatic increase in seismicity due to an aftershock sequence can easily cause the bulletin delay time to increase dramatically. In some cases, the production of a bulletin may cease altogether, until the automatic system can catch up. For a nuclear monitoring system, the implications of such a delay could be dire. Given the expected similarity between a mainshock and aftershocks, it has been proposed that waveform correlation may provide a powerful means to simultaneously increase the efficiency of processing aftershock sequences, while also lowering the detection threshold and improving the quality of the event solutions. However, many questions remain unanswered. What are the key parameters for achieving the best correlations between waveforms (window length, filtering, etc.), and are they sequence-dependent? What is the overall percentage of similar events in an aftershock sequence, i.e. what is the maximum level of efficiency that a waveform correlation could be expected to achieve? Finally, how does this percentage of events vary among sequences? Using data from the aftershock sequence for the December 26, 2004 Mw 9.1 Sumatra event, we investigate these issues by building and testing a prototype waveform correlation event detection system that automatically expands its library of known events as new signatures are indentified in the aftershock sequence (by traditional signal detection and event processing). Our system tests all incoming data against this dynamic library, thereby identify any similar events before traditional processing takes place. In the region surrounding the Sumatra event, the NEIC EDR contains 4997 events in the 9

  15. Scintigraphy and Doppler ultrasonography for the evaluation of obstructive urinary calculi

    L. Gandolpho


    Full Text Available Forty-seven patients with unilateral obstructive calculi (12 males and 35 females were submitted to 99mTc-diethylene triamine pentaacetic acid (DTPA or 99mTc-dimercaptosuccinic acid (DMSA scans for assessment of renal function. The scans revealed unilateral functional deficit in 68 and 66% of the patients, respectively. A calculus size of 1.1 to 2.0 cm was significantly associated with deficit detected by DTPA, but duration of obstruction and calculus localization were not. After relief of the obstruction, the mean percent renal function of the affected kidney was found to be significantly increased from 25 ± 12% to 29 ± 12% in DTPA and from 21 ± 15% to 24 ± 12% in DMSA. Initial Doppler ultrasonography performed in 35 patients detected an increased resistive index in 10 (29%. In the remaining patients with a normal resistive index, ureteral urinary jet was observed, indicating partial obstruction. The high frequency of renal function impairment detected by DTPA and of tubulointerstitial damage detected by DMSA as well as the slight amelioration of unilateral renal function after relief of obstruction suggest that scintigraphy assessment may help evaluate the unilateral percentage of renal function and monitor renal function recovery when it occurs. The presence of a urinary jet detected by Doppler ultrasonography further indicates the severity of obstruction and the recovery prognosis.


    Charitha GN


    Full Text Available Renal blood supply presents a large degree of variations. In the present case there was existence of bilateral variations in renal blood supply along with right sided bifid ureter. During routine cadaveric dissection in a middle aged male cadaver we found two renal veins draining right kidney and a bifurcating single renal vein on left side. On both sides one polar artery arising from main renal artery going to upper pole of kidney and left side accessory renal artery originating from abdominal aorta and giving origin to left testicular artery were observed. There is bifid ureter on the right side. The knowledge of renal vascular anatomy and its variations are very much essential in case of renal transplantation, renal surgeries, uroradiology, gonadal color Doppler imaging, in abdominal aortic aneurysmal and gonadal surgeries.


    蔡胜; 李建初; 姜玉新; 戴晴; 谭莉; 张缙熙


    Objective. To study the sonographic features and patterns of cystic renal carcinomas. Methods. Thirteen cases of cystic renal carcinoma confirmed by operation and pathology were examined by ultrasonography, and the cystic walls, septa and solid mural nodules were studied. Results. Solid mural nodules of some cases and irregular thickening of the cystic walls and septa were characteristic findings for the ultrasonic diagnosis of cystic renal carcinomas. According to their pathologic mechanisms and sonographic features, cystic renal carcinomas were classified into 3 patterns: unilocular cystic mass, multiloculated cystic mass and cystic-solid mass. Conclusions. Typical cystic renal carcinomas can be well diagnosed, while atypical cases may be misdiagnosed as benign renal cysts by ultrasonography. Color Doppler ultrasonography and needle aspiration guided by ultrasonography are helpful in the diagnosis of these atypical cases.


    蔡胜; 李建初; 等


    Objective:To study the sonographic features and patterns of cystic renal carcinomas.Methods:Thirteen cases of cystic renal carcinoma confirmed by operation and pathology were examined by ultrasonography,and the cystic walls,septa and solid mural nodules were studied.Results:Solid mural nodules of some cases and irregular thickening of the cystic walls and septa were characteristic findings for the ultrasonic diagnosis of cystic renal carcinomas.According to their pathologic mechanisms and sonographic features,cystic renal carcinomas were classified into 3 patterns:unilocular cystic mass,multiloculated cystic mass and cystic-solid mass.Conclusions:Typical cystic renal carcinomas can be well diagnosed,while atypical cases may be misdiagnosed as benign renal cysts by ultrasonography.Color Doppler ultrasonography and needle aspiration guided by ultrasonography are helpful in the diagnosis of these atypical cases.

  19. Sarcoidose renal



    Full Text Available Em uma mulher de 62 anos, branca, em avaliação pré-operatória de facectomia, foram detectadas alterações urinárias, tendo sido firmados os diagnósticos de calculose renal esquerda e exclusão renal homolateral. No pré-operatório da nefrectomia foram evidenciados processo pulmonar intersticial bilateral e adenopatia torácica, cuja investigação foi adiada para após a cirurgia. No rim retirado foram detectados granulomas epitelióides não necrotizantes, o mesmo ocorrendo posteriormente em biópsia transbrônquica. A paciente foi tratada com metilprednisolona, com discreta melhora pulmonar, o que não ocorreu com a função renal. O diagnóstico final foi de sarcoidose com envolvimento pulmonar, ganglionar torácico e renal.

  20. Renal failure


    930150 Epidermal growth factor and its recep-tor in the renal tissue of patients with acute re-nal failure and normal persons.LIU Zhihong(刘志红),et al.Jinling Hosp,Nanjing,210002.Natl Med J China 1992;72(10):593-595.Epidermal growth factor(EGF)and its receptor(EGF-R)were identified by immunohis-tochemical method(4 layer PAP)in the renaltissue specimens obtained from 11 normal kid-neys and 17 cases of acute renal failure(ARF).The quantitative EGF and EGF-R in the tissuewere expressed as positive tubules per mm~2.The amount of EGF and EGF-R in renal tissue

  1. The Multiple Waveform Persistent Peak (MWaPP) Retracker for SAR waveforms

    Villadsen, Heidi; Andersen, Ole Baltazar; Stenseng, Lars

    using CryoSat-2 20Hz SAR data, but due to the similarities between the Sentinel-3 SRAL altimeter and the SIRAL altimeter on-board CryoSat-2 an adaption of the method will be straightforward. The MWaPP retracker is based on a sub-waveform retracker, but takes the shape of adjacent waveforms into account...... before selecting the sub-waveform belonging to nadir. This is new compared to primary peak retrackers, and alleviates a lot of snagging due to off-nadir bright targets, but also topography challenges. The results from the MWaPP retracker show a significant decrease in the standard deviation of the mean...

  2. Renal failure


    2005234 Association between serum fetuin-A and clinical outcome in end-stage renal disease patients. WANG Kai(王开), Dept Renal Dis, Renji Hosp Shanghai, 2nd Med Univ, Shanghai 200001. Chin J Nephrol, 2005;21(2):72-75. Objective: To investigate the change of serum fetuin-A level before and after dialysis, and the association of serum fetuin-A level with clinical parameters

  3. Renal failure


    950351 Serum erythropoietin levels in chronic renalinsufficiency.ZHAI Depei(翟德佩),et al.DeptNephrol.General Hosp,Tianjin Med Univ,Tianjin,300000.Tianjin Med J 1995;23(1):19-21.Patients with chronic renal insufficiency(CRI) areoften associated with anemia.The deficiency of EPOproduction in the kidney is thought to be a key factorin the pathogenesis of renal anemia.Serum erythropoi-

  4. Renal failure


    2008463 Protective effect of recombination rat augmenter of liver regeneration on kidney in acute renal failure rats. TANG Xiaopeng(唐晓鹏), et al. Dept Nephrol, 2nd Affili Hosp Chongqing Med Univ, Chongqing 400010.Chin J Nephrol 2008;24(6):417-421. Objective To investigate the protective effects of recombination rat augmenter of liver regeneration (rrALR) on tubular cell injury and renal dysfunction

  5. Renal Hemangiopericytoma

    İbrahim Halil Bozkurt


    Full Text Available Hemangiopericytoma is an uncommon perivascular tumor originating from pericytes in the pelvis, head and tneck, and the meninges; extremely rarely in the urinary system. We report a case of incidentally detected renal mass in which radiologic evaluation was suggestive of renal cell carcinoma. First, we performed partial nephrectomy, and then, radical nephrectomy because of positive surgical margins and the pathological examination of the surgical specimen that revealed a hemangiopericytoma. No additional treatment was administered.

  6. Doppler peaks from active perturbations

    Magueijo, J; Coulson, D; Ferreira, P; Magueijo, Joao; Albrecht, Andreas; Coulson, David; Ferreira, Pedro


    We examine how the qualitative structure of the Doppler peaks in the angular power spectrum of the cosmic microwave anisotropy depends on the fundamental nature of the perturbations which produced them. The formalism of Hu and Sugiyama is extended to treat models with cosmic defects. We discuss how perturbations can be ``active'' or ``passive'' and ``incoherent'' or ``coherent'', and show how causality and scale invariance play rather different roles in these various cases. We find that the existence of secondary Doppler peaks and the rough placing of the primary peak unambiguously reflect these basic properties.

  7. Inverse Doppler Effects in Flute

    Zhao, Xiao P; Liu, Song; Shen, Fang L; Li, Lin L; Luo, Chun R


    Here we report the observation of the inverse Doppler effects in a flute. It is experimentally verified that, when there is a relative movement between the source and the observer, the inverse Doppler effect could be detected for all seven pitches of a musical scale produced by a flute. Higher tone is associated with a greater shift in frequency. The effect of the inverse frequency shift may provide new insights into why the flute, with its euphonious tone, has been popular for thousands of years in Asia and Europe.

  8. The Next Generation Airborne Polarimetric Doppler Radar

    Vivekanandan, J.; Lee, Wen-Chau; Loew, Eric; Salazar, Jorge; Chandrasekar, V.


    NCAR's Electra Doppler radar (ELDORA) with a dual-beam slotted waveguide array using dual-transmitter, dual-beam, rapid scan and step-chirped waveform significantly improved the spatial scale to 300m (Hildebrand et al. 1996). However, ELDORA X-band radar's penetration into precipitation is limited by attenuation and is not designed to collect polarimetric measurements to remotely estimate microphysics. ELDORA has been placed on dormancy because its airborne platform (P3 587) was retired in January 2013. The US research community has strongly voiced the need to continue measurement capability similar to the ELDORA. A critical weather research area is quantitative precipitation estimation/forecasting (QPE/QPF). In recent years, hurricane intensity change involving eye-eyewall interactions has drawn research attention (Montgomery et al., 2006; Bell and Montgomery, 2006). In the case of convective precipitation, two issues, namely, (1) when and where convection will be initiated, and (2) determining the organization and structure of ensuing convection, are key for QPF. Therefore collocated measurements of 3-D winds and precipitation microphysics are required for achieving significant skills in QPF and QPE. Multiple radars in dual-Doppler configuration with polarization capability estimate dynamical and microphysical characteristics of clouds and precipitation are mostly available over land. However, storms over complex terrain, the ocean and in forest regions are not observable by ground-based radars (Bluestein and Wakimoto, 2003). NCAR/EOL is investigating potential configurations for the next generation airborne radar that is capable of retrieving dynamic and microphysical characteristics of clouds and precipitation. ELDORA's slotted waveguide array radar is not compatible for dual-polarization measurements. Therefore, the new design has to address both dual-polarization capability and platform requirements to replace the ELDORA system. NCAR maintains a C-130

  9. Doppler tomography in fusion plasmas and astrophysics

    Salewski, Mirko; Heidbrink, Bill; Jacobsen, Asger Schou; Korsholm, Soren Bang; Leipold, Frank; Madsen, Jens; Moseev, Dmitry; Nielsen, Stefan Kragh; Rasmussen, Jesper; Stagner, Luke; Steeghs, Danny; Stejner, Morten; Tardini, Giovani; Weiland, Markus


    Doppler tomography is a well-known method in astrophysics to image the accretion flow, often in the shape of thin discs, in compact binary stars. As accretion discs rotate, all emitted line radiation is Doppler-shifted. In fast-ion D-alpha (FIDA) spectroscopy measurements in magnetically confined plasma, the D-alpha-photons are likewise Doppler-shifted ultimately due to gyration of the fast ions. In either case, spectra of Doppler-shifted line emission are sensitive to the velocity distribution of the emitters. Astrophysical Doppler tomography has lead to images of accretion discs of binaries revealing bright spots, spiral structures, and flow patterns. Fusion plasma Doppler tomography has lead to an image of the fast-ion velocity distribution function in the tokamak ASDEX Upgrade. This image matched numerical simulations very well. Here we discuss achievements of the Doppler tomography approach, its promise and limits, analogies and differences in astrophysical and fusion plasma Doppler tomography, and what ...

  10. Doppler Ultrasound: What Is It Used for?

    ... in your neck (carotid artery stenosis) A Doppler ultrasound can estimate how fast blood flows by measuring the rate of change in its pitch (frequency). During a Doppler ultrasound, a technician trained in ultrasound imaging (sonographer) presses ...

  11. Best waveform score for diagnosing keratoconus

    Allan Luz


    Full Text Available PURPOSE: To test whether corneal hysteresis (CH and corneal resistance factor (CRF can discriminate between keratoconus and normal eyes and to evaluate whether the averages of two consecutive measurements perform differently from the one with the best waveform score (WS for diagnosing keratoconus. METHODS: ORA measurements for one eye per individual were selected randomly from 53 normal patients and from 27 patients with keratoconus. Two groups were considered the average (CH-Avg, CRF-Avg and best waveform score (CH-WS, CRF-WS groups. The Mann-Whitney U-test was used to evaluate whether the variables had similar distributions in the Normal and Keratoconus groups. Receiver operating characteristics (ROC curves were calculated for each parameter to assess the efficacy for diagnosing keratoconus and the same obtained for each variable were compared pairwise using the Hanley-McNeil test. RESULTS: The CH-Avg, CRF-Avg, CH-WS and CRF-WS differed significantly between the normal and keratoconus groups (p<0.001. The areas under the ROC curve (AUROC for CH-Avg, CRF-Avg, CH-WS, and CRF-WS were 0.824, 0.873, 0.891, and 0.931, respectively. CH-WS and CRF-WS had significantly better AUROCs than CH-Avg and CRF-Avg, respectively (p=0.001 and 0.002. CONCLUSION: The analysis of the biomechanical properties of the cornea through the ORA method has proved to be an important aid in the diagnosis of keratoconus, regardless of the method used. The best waveform score (WS measurements were superior to the average of consecutive ORA measurements for diagnosing keratoconus.

  12. Preconditioning Strategies in Elastic Full Waveform Inversion.

    Matharu, G.; Sacchi, M. D.


    Elastic full waveform inversion (FWI) is inherently more non-linear than its acoustic counterpart, a property that stems from the increased model space of the problem. Whereas acoustic media can be parametrized by density and P-wave velocity, visco-elastic media are parametrized by density, attenuation and 21 independent coefficients of the elastic tensor. Imposing assumptions of isotropy and perfect elasticity to simplify the physics, reduces the number of independent parameters required to characterize a medium. Isotropic, elastic media can be parametrized in terms of density and the Lamé parameters. The different parameters can exhibit trade-off that manifest as attributes in the data. In the context of FWI, this means that certain parameters cannot be uniquely resolved. An ideal model update in full waveform inversion is equivalent to a Newton step. Explicit computation of the Hessian and its inverse is not computationally feasible in elastic FWI. The inverse Hessian scales the gradients to account for trade-off between parameters as well as compensating for inadequate illumination related to source-receiver coverage. Gradient preconditioners can be applied to mimic the action of the inverse Hessian and partially correct for inaccuracies in the gradient. In this study, we investigate the effects of model reparametrization by recasting a regularized form of the least-squares waveform misfit into a preconditioned formulation. New model parameters are obtained by applying invertible weighting matrices to the model vector. The weighting matrices are related to estimates of the prior model covariance matrix and incorporate information about spatially variant correlations of model parameters as well as correlations between independent parameters. We compare the convergence of conventional FWI to FWI after model reparametrization.

  13. Velocity-aligned Doppler spectroscopy

    Xu, Z.; Koplitz, B.; Wittig, C.


    The technique of velocity-aligned Doppler spectrosocopy (VADS) is presented and discussed. For photolysis/probe experiments with pulsed initiation, VADS can yield Doppler profiles for nascent photofragments that allow detailed center-of-mass (c.m.) kinetic energy distributions to be extracted. When compared with traditional forms of Doppler spectroscopy, the improvement in kinetic energy resolution is dramatic. Changes in the measured profiles are a consequence of spatial discrimination (i.e., focused and overlapping photolysis and probe beams) and delayed observation. These factors result in the selective detection of species whose velocities are aligned with the wave vector of the probe radiation k/sub pr/, thus revealing the speed distribution along k/sub pr/ rather than the distribution of nascent velocity components projected upon this direction. Mathematical details of the procedure used to model VADS are given, and experimental illustrations for HI, H/sub 2/S, and NH/sub 3/ photodissociation are presented. In these examples, pulsed photodissociation produces H atoms that are detected by sequential two-photon, two-frequency ionization via Lyman-..cap alpha.. with a pulsed laser (121.6+364.7 nm), and measuring the Lyman-..cap alpha.. Doppler profile as a function of probe delay reveals both internal and c.m. kinetic energy distributions for the photofragments. Strengths and weaknesses of VADS as a tool for investigating photofragmentation phenomena are also discussed.

  14. Speckles in laser doppler perfusion imaging

    Rajan, Vinayakrishnan


    Laser Doppler Flowmetry (LDF) is a noninvasive diagnostic method to measure blood flow in tissue [1]. The technique is based on measuring the Doppler shift induced by moving red blood cells to the illuminating coherent light. A laser Doppler instrument often gives output signals related to the flux,

  15. Micro-Doppler Analysis of Small UAVs

    Wit, J.J.M. de; Harmanny, R.I.A.; Prémel Cabic, G.


    Coherent radar measures micro-Doppler properties of moving objects. The micro-Doppler signature depends on parts of an object moving and rotating in addition to the main body motion (e.g. rotor blades) and is therefore characteristic for the type of object. In this study, the micro-Doppler signature

  16. Micro-Doppler Analysis of Small UAVs

    Wit, J.J.M. de; Harmanny, R.I.A.; Prémel Cabic, G.


    Coherent radar measures micro-Doppler properties of moving objects. The micro-Doppler signature depends on parts of an object moving and rotating in addition to the main body motion (e.g. rotor blades) and is therefore characteristic for the type of object. In this study, the micro-Doppler signature

  17. The Doppler Effect--A New Approach

    Allen, J.


    Discusses the Doppler effect as it applies to different situations, such as a stationary source of sound with the observer moving, a stationary observer, and the sound source and observer both moving. Police radar, satellite surveillance radar, radar astronomy, and the Doppler navigator, are discussed as applications of Doppler shift. (JR)

  18. Optimal Transport for Seismic Full Waveform Inversion

    Engquist, Bjorn; Yang, Yunan


    Full waveform inversion is a successful procedure for determining properties of the earth from surface measurements in seismology. This inverse problem is solved by a PDE constrained optimization where unknown coefficients in a computed wavefield are adjusted to minimize the mismatch with the measured data. We propose using the Wasserstein metric, which is related to optimal transport, for measuring this mismatch. Several advantageous properties are proved with regards to convexity of the objective function and robustness with respect to noise. The Wasserstein metric is computed by solving a Monge-Ampere equation. We describe an algorithm for computing its Frechet gradient for use in the optimization. Numerical examples are given.

  19. A new earthquake location method based on the waveform inversion

    Wu, Hao; Huang, Xueyuan; Yang, Dinghui


    In this paper, a new earthquake location method based on the waveform inversion is proposed. As is known to all, the waveform misfit function is very sensitive to the phase shift between the synthetic waveform signal and the real waveform signal. Thus, the convergence domain of the conventional waveform based earthquake location methods is very small. In present study, by introducing and solving a simple sub-optimization problem, we greatly expand the convergence domain of the waveform based earthquake location method. According to a large number of numerical experiments, the new method expands the range of convergence by several tens of times. This allows us to locate the earthquake accurately even from some relatively bad initial values.

  20. Multi-waveform classification for seismic facies analysis

    Song, Chengyun; Liu, Zhining; Wang, Yaojun; Li, Xingming; Hu, Guangmin


    Seismic facies analysis provides an effective way to delineate the heterogeneity and compartments within a reservoir. Traditional method is using the single waveform to classify the seismic facies, which does not consider the stratigraphy continuity, and the final facies map may affect by noise. Therefore, by defining waveforms in a 3D window as multi-waveform, we developed a new seismic facies analysis algorithm represented as multi-waveform classification (MWFC) that combines the multilinear subspace learning with self-organizing map (SOM) clustering techniques. In addition, we utilize multi-window dip search algorithm to extract multi-waveform, which reduce the uncertainty of facies maps in the boundaries. Testing the proposed method on synthetic data with different S/N, we confirm that our MWFC approach is more robust to noise than the conventional waveform classification (WFC) method. The real seismic data application on F3 block in Netherlands proves our approach is an effective tool for seismic facies analysis.

  1. Estimation of cardiac output and total peripheral resistance in preterm infants by arterial waveform analysis.

    Zhang, Ying; Chan, Gregory S H; Tracy, Mark B; Hinder, Murray; Redmond, Stephen J; Savkin, Andrey V; Lovell, Nigel H


    This study investigated whether arterial blood pressure waveform analysis could be useful for estimating left ventricular outflow (LVO) and total peripheral resistance (TPR) in preterm infants. A cohort of 27 infants were studied, with 89 measurements of left ventricular outflow (LVO) using Doppler echocardiography and arterial pressure using catheters, performed in 0, 12, 24 and 36 hours after birth. TPR was computed as mean arterial pressure divided by LVO. The diastolic decay rate (1/τ) was obtained via fitting an exponential function to the last one third of each arterial pulse, with the mean rate computed from 50 pulses selected from each infant. This decay rate was considered to be inversely related to TPR while positively related to LVO. The results of regression analysis have confirmed that the diastolic decay rate had significant positive and negative relationships with LVO and TPR respectively(r = 0.383, P = 0.0002 and r = -0.379, P = 0.0002 respectively). These preliminary results demonstrated the potential utility of arterial pressure waveform analysis for estimating LVO and TPR in preterm infants, but more advanced multi-parameter models may be needed to improve accuracy of the estimation.

  2. Hyponatremic Hypertensive Syndrome in an Obese Man with Renal Ischemia

    Saeed Khawer


    Full Text Available Renovascular hypertension occasionally manifests as an electrolyte disorder. The combination of hyponatremia and renovascular hypertension is known as hyponatremic-hypertensive syndrome. This syndrome was initially reported in children. Here, we describe a 45 year-old Saudi man who was admitted to the hospital with generalized body weakness and inability to walk. He was confused and was noted to have severe hypertension and very low serum sodium and potassium. The patient was recently started on captopril for blood pressure control, which was discontinued because of deterioration of renal function. Color Doppler renal ultrasound, and magnetic resonance angiography confirmed the diagnosis of renal artery stenosis.

  3. Audio spectrum analysis of umbilical artery Doppler ultrasound signals applied to a clinical material.

    Thuring, Ann; Brännström, K Jonas; Jansson, Tomas; Maršál, Karel


    Analysis of umbilical artery flow velocity waveforms characterized by pulsatility index (PI) is used to evaluate fetoplacental circulation in high-risk pregnancies. However, an experienced sonographer may be able to further differentiate between various timbres of Doppler audio signals. Recently, we have developed a method for objective audio signal characterization; the method has been tested in an animal model. In the present pilot study, the method was for the first time applied to human pregnancies. Doppler umbilical artery velocimetry was performed in 13 preterm fetuses before and after two doses of 12 mg betamethasone. The auditory measure defined by the frequency band where the spectral energy had dropped 15 dB from its maximum level (MAXpeak-15 dB ), increased two days after betamethasone administration (p = 0.001) parallel with a less pronounced decrease in PI (p = 0.04). The new auditory parameter MAXpeak-15 dB reflected the changes more sensitively than the PI did.

  4. Low Complexity Direction and Doppler Frequency Estimation for Bistatic MIMO Radar in Spatial Colored Noise

    Lingyun Xu


    Full Text Available We investigate the algorithm of direction and Doppler frequency estimation for bistatic multiple-input multiple-output (MIMO radar in spatial colored noise. A novel method of joint estimation of direction and Doppler frequency in spatial colored noise based on propagator method (PM for bistatic MIMO radar is discussed. Utilizing the cross-correlation matrix which is formed by the adjacent outputs of match filter in the time domain, the special matrix is constructed to eliminate the influence of spatial colored noise. The proposed algorithm provides lower computational complexity and has very close parameters estimation compared to estimation of signal parameters via rotational invariance technique (ESPRIT algorithm in high signal-to-noise ratio (SNR. It is applicable even if the transmitted waveforms are not orthogonal. The estimated parameters can be paired automatically and the Cramér-Rao Bound (CRB is given in spatial colored noise. Simulation results confirm the effectiveness of the proposed method.

  5. Waveform Optimization for SWIPT with Nonlinear Energy Harvester Modeling

    Clerckx, Bruno


    Simultaneous Wireless Information and Power Transfer (SWIPT) has attracted significant attention in the communication community. The problem of waveform design for SWIPT has however never been addressed so far. In this paper, a novel SWIPT transceiver architecture is introduced relying on the superposition of multisine and OFDM waveforms at the transmitter and a power-splitter receiver equipped with an energy harvester and an information decoder capable of cancelling the multisine waveforms. ...

  6. RF arbitrary waveform generation using tunable planar lightwave circuits

    Samadi, P.; Chen, L. R.; Callender, C.; Dumais, P.; Jacob, S.; Celo, D.


    We demonstrate photonically-assisted generation of RF arbitrary waveforms using planar lightwave circuits (PLCs) fabricated on silica-on-silicon. We exploit thermo-optic effects in silica in order to tune the response of the PLC and hence reconfigure the generated waveform. We demonstrate the generation of pulse trains at 40 GHz and 80 GHz with flat-top, Gaussian, and apodized profiles. These results demonstrate the potential for RF arbitrary waveform generation using chip-scale photonic solutions.

  7. Information Encoding on a Pseudo Random Noise Radar Waveform



  8. Adaptive multi-step Full Waveform Inversion based on Waveform Mode Decomposition

    Hu, Yong; Han, Liguo; Xu, Zhuo; Zhang, Fengjiao; Zeng, Jingwen


    Full Waveform Inversion (FWI) can be used to build high resolution velocity models, but there are still many challenges in seismic field data processing. The most difficult problem is about how to recover long-wavelength components of subsurface velocity models when seismic data is lacking of low frequency information and without long-offsets. To solve this problem, we propose to use Waveform Mode Decomposition (WMD) method to reconstruct low frequency information for FWI to obtain a smooth model, so that the initial model dependence of FWI can be reduced. In this paper, we use adjoint-state method to calculate the gradient for Waveform Mode Decomposition Full Waveform Inversion (WMDFWI). Through the illustrative numerical examples, we proved that the low frequency which is reconstructed by WMD method is very reliable. WMDFWI in combination with the adaptive multi-step inversion strategy can obtain more faithful and accurate final inversion results. Numerical examples show that even if the initial velocity model is far from the true model and lacking of low frequency information, we still can obtain good inversion results with WMD method. From numerical examples of anti-noise test, we see that the adaptive multi-step inversion strategy for WMDFWI has strong ability to resist Gaussian noise. WMD method is promising to be able to implement for the land seismic FWI, because it can reconstruct the low frequency information, lower the dominant frequency in the adjoint source, and has a strong ability to resist noise.

  9. On the accuracy and precision of numerical waveforms: effect of waveform extraction methodology

    Chu, Tony; Fong, Heather; Kumar, Prayush; Pfeiffer, Harald P.; Boyle, Michael; Hemberger, Daniel A.; Kidder, Lawrence E.; Scheel, Mark A.; Szilagyi, Bela


    We present a new set of 95 numerical relativity simulations of non-precessing binary black holes (BBHs). The simulations sample comprehensively both black-hole spins up to spin magnitude of 0.9, and cover mass ratios 1-3. The simulations cover on average 24 inspiral orbits, plus merger and ringdown, with low initial orbital eccentricities e\\lt {10}-4. A subset of the simulations extends the coverage of non-spinning BBHs up to mass ratio q = 10. Gravitational waveforms at asymptotic infinity are computed with two independent techniques: extrapolation and Cauchy characteristic extraction. An error analysis based on noise-weighted inner products is performed. We find that numerical truncation error, error due to gravitational wave extraction, and errors due to the Fourier transformation of signals with finite length of the numerical waveforms are of similar magnitude, with gravitational wave extraction errors dominating at noise-weighted mismatches of ˜ 3× {10}-4. This set of waveforms will serve to validate and improve aligned-spin waveform models for gravitational wave science.

  10. Focal waveforms for various source waveforms driving a prolate-spheroidal impulse radiating antenna (IRA)

    Altunc, Serhat; Baum, Carl E.; Christodoulou, Christos G.; Schamiloglu, Edl; Buchenauer, C. Jerald


    Impulse radiating antennas (IRAs) are designed to radiate very fast pulses in a narrow beam with low dispersion and high field amplitude. For this reason they have been used in a variety of applications. IRAs have been developed for use in the transient far-field region using parabolic reflectors. However, in this paper we focus in the near field region and develop the field waveform at the second focus of a prolate-spheroidal IRA. Certain skin cancers can be killed by the application of a high-amplitude electric field pulse. This can be accomplished by either inserting electrodes near the skin cancer or by applying fast, high-electric field pulses without direct contact. We investigate a new manifestation of an IRA, in which we use a prolate spheroid as a reflector instead of a parabolic reflector and focus in the near-field region instead of the far-field region. This technique minimizes skin damage associated with inserting electrodes near the tumor. Analytical and experimental behaviors for the focal waveforms of two and four-feed arm prolate-spheroidal IRAs are explored. With appropriate choice of the driving waveform we maximize the impulse field at the second focus. The focal waveform of a prolate-spheroidal IRA has been explained theoretically and verified experimentally.

  11. Waveform interative techniques for device transient simulation on parallel machines

    Lumsdaine, A. [Univ. of Notre Dame, IN (United States); Reichelt, M.W. [Massachusetts Institute of Technology, Cambridge, MA (United States)


    In this paper we describe our experiences with parallel implementations of several different waveform algorithms for performing transient simulation of semiconductor devices. Because of their inherent computation and communication structure, waveform methods are well suited to MIMD-type parallel machines having a high communication latency - such as a cluster of workstations. Experimental results using pWORDS, a parallel waveform-based device transient simulation program, in conjunction with PVM running on a cluster of eight workstations demonstrate that parallel waveform techniques are an efficient and faster alternative to standard simulation algorithms.

  12. Adaptive Robust Waveform Selection for Unknown Target Detection in Clutter

    Lu-Lu Wang; Hong-Qiang Wang; Yu-Liang Qin; Yong-Qiang Cheng


    @@@A basic assumption of most recently proposed waveform design algorithms is that the target impulse response is a known deterministic function or a stochastic process with a known power spectral density (PSD). However, it is well-known that a target impulse response is neither easily nor accurately obtained; besides it changes sharply with attitude angles. Both of the aforementioned cases complicate the waveform design process. In this paper, an adaptive robust waveform selection method for unknown target detection in clutter is proposed. The target impulse response is considered to be unknown but belongs to a known uncertainty set. An adaptive waveform library is devised by using a signal-to-clutter-plus-noise ratio (SCNR)- based optimal waveform design method. By applying the minimax robust waveform selection method, the optimal robust waveform is selected to ensure the lowest performance bound of the unknown target detection in clutter. Results show that the adaptive waveform library outperforms the predefined linear frequency modulation (LFM) waveform library on the SCNR bound.

  13. Advances in waveform-agile sensing for tracking

    Sira, Sandeep Prasad


    Recent advances in sensor technology and information processing afford a new flexibility in the design of waveforms for agile sensing. Sensors are now developed with the ability to dynamically choose their transmit or receive waveforms in order to optimize an objective cost function. This has exposed a new paradigm of significant performance improvements in active sensing: dynamic waveform adaptation to environment conditions, target structures, or information features. The manuscript provides a review of recent advances in waveform-agile sensing for target tracking applications. A dynamic wav

  14. Waveform Freezing of Sonic Booms Revisited

    Cleveland, Robin O.; Blackstock, David T.


    Nonlinear distortion of sonic booms propagating in the atmosphere is strongly affected by stratification and geometrical spreading. For a downward propagating sonic boom in a standard atmosphere, stratification and spreading cause a slowing down of nonlinear distortion. In certain cases a stage is reached where no further distortion takes place. When this happens, the waveform is said to be frozen. In previous work the authors argued that for most HSCT designs and flight conditions being considered, the sonic boom is not frozen when it reaches the ground. The criterion used was the value of the distortion distance x bar is a measure of the nonlinear distortion suffered by the wave (and is closely related to Hayes's E variable). The aircraft must be at an altitude greater than 27 km (80,000 ft) for x bar at the groun be within 95% of its asymptotic value. However, work reported here demonstrates that the ground waveform is much closer to the frozen state than indicated by the previous analysis. In the new analysis, duration of the sonic boom is used as the criterion for judging closeness of approach tz frozen state. In order for the duration of the sonic boom at the ground to be within 95% of its frozen value, the flight altitude of the aircraft needs to be only 15 km (45,000 ft).

  15. Elastic reflection waveform inversion with variable density

    Li, Yuanyuan


    Elastic full waveform inversion (FWI) provides a better description of the subsurface than those given by the acoustic assumption. However it suffers from a more serious cycle skipping problem compared with the latter. Reflection waveform inversion (RWI) provides a method to build a good background model, which can serve as an initial model for elastic FWI. Therefore, we introduce the concept of RWI for elastic media, and propose elastic RWI with variable density. We apply Born modeling to generate the synthetic reflection data by using optimized perturbations of P- and S-wave velocities and density. The inversion for the perturbations in P- and S-wave velocities and density is similar to elastic least-squares reverse time migration (LSRTM). An incorrect initial model will lead to some misfits at the far offsets of reflections; thus, can be utilized to update the background velocity. We optimize the perturbation and background models in a nested approach. Numerical tests on the Marmousi model demonstrate that our method is able to build reasonably good background models for elastic FWI with absence of low frequencies, and it can deal with the variable density, which is needed in real cases.

  16. Azimuthal Doppler Effect in Optical Vortex Spectroscopy

    Aramaki, Mitsutoshi; Yoshimura, Shinji; Toda, Yasunori; Morisaki, Tomohiro; Terasaka, Kenichiro; Tanaka, Masayoshi


    Optical vortices (OV) are a set of solutions of the paraxial Helmholtz equation in the cylindrical coordinates, and its wave front has a spiral shape. Since the Doppler shift is caused by the phase change by the movement in a wave field, the observer in the OV, which has the three-dimensional structured wave front, feels a three-dimensional Doppler effect. Since the multi-dimensional Doppler components are mixed into a single Doppler spectrum, development of a decomposition method is required. We performed a modified saturated absorption spectroscopy to separate the components. The OV and plane wave are used as a probe beam and pump beam, respectively. Although the plane-wave pump laser cancels the z-direction Doppler shift, the azimuthal Doppler shift remains in the saturated dip. The spatial variation of the dip width gives the information of the azimuthal Doppler shift. The some results of optical vortex spectroscopy will be presented.

  17. Velocity-aligned Doppler spectroscopy

    Xu, Z.; Koplitz, B.; Wittig, C.


    The use of velocity-aligned Doppler spectroscopy (VADS) to measure center-of-mass kinetic-energy distributions of nascent photofragments produced in pulsed-initiation photolysis/probe experiments is described and demonstrated. In VADS, pulsed photolysis and probe laser beams counterpropagate through the ionization region of a time-of-flight mass spectrometer. The theoretical principles of VADS and the mathematical interpretation of VADS data are explained and illustrated with diagrams; the experimental setup is described; and results for the photodissociation of HI, H2S, and NH3 are presented in graphs and characterized in detail. VADS is shown to give much higher kinetic-energy resolution than conventional Doppler spectroscopy.

  18. Renal Cysts

    ... as “simple” cysts, meaning they have a thin wall and contain water-like fluid. Renal cysts are fairly common in ... simple kidney cysts, meaning they have a thin wall and only water-like fluid inside. They are fairly common in ...

  19. Renal failure


    970363 Effect on serum PTH and 1, 25(OH)2 D3levels of rapid correction of metabolic acidosis in CRFpatients with secondary hyperparathyroidism. YUANQunsheng(袁群生), et al. Renal Div, PUMC Hosp,Beijing, 100730. Chin J Nephrol 1996; 12(6): 328-331.


    Helmberger, D; Tromp, J; Rodgers, A


    Comprehensive test ban monitoring in terms of location and discrimination has progressed significantly in recent years. However, the characterization of sources and the estimation of low yields remains a particular challenge. As the recent Korean shot demonstrated, we can probably expect to have a small set of teleseismic, far-regional and high-frequency regional data to analyze in estimating the yield of an event. Since stacking helps to bring signals out of the noise, it becomes useful to conduct comparable analyses on neighboring events, earthquakes in this case. If these auxiliary events have accurate moments and source descriptions, we have a means of directly comparing effective source strengths. Although we will rely on modeling codes, 1D, 2D, and 3D, we will also apply a broadband calibration procedure to use longer periods (P>5s) waveform data to calibrate short-period (P between .5 to 2 Hz) and high-frequency (P between 2 to 10 Hz) as path specify station corrections from well-known regional sources. We have expanded our basic Cut-and-Paste (CAP) methodology to include not only timing shifts but also amplitude (f) corrections at recording sites. The name of this method was derived from source inversions that allow timing shifts between 'waveform segments' (or cutting the seismogram up and re-assembling) to correct for crustal variation. For convenience, we will refer to these f-dependent refinements as CAP+ for (SP) and CAP++ for still higher frequency. These methods allow the retrieval of source parameters using only P-waveforms where radiation patterns are obvious as demonstrated in this report and are well suited for explosion P-wave data. The method is easily extended to all distances because it uses Green's function although there may be some changes required in t* to adjust for offsets between local vs. teleseismic distances. In short, we use a mixture of model-dependent and empirical corrections to tackle the path effects. Although

  1. Towards Full-Waveform Ambient Noise Inversion

    Sager, Korbinian; Ermert, Laura; Afanasiev, Michael; Boehm, Christian; Fichtner, Andreas


    Noise tomography usually works under the assumption that the inter-station ambient noise correlation is equal to a scaled version of the Green function between the two receivers. This assumption, however, is only met under specific conditions, e.g. wavefield diffusivity and equipartitioning, or the isotropic distribution of both mono- and dipolar uncorrelated noise sources. These assumptions are typically not satisfied in the Earth. This inconsistency inhibits the exploitation of the full waveform information contained in noise correlations in order to constrain Earth structure and noise generation. To overcome this limitation, we attempt to develop a method that consistently accounts for the distribution of noise sources, 3D heterogeneous Earth structure and the full seismic wave propagation physics. This is intended to improve the resolution of tomographic images, to refine noise source distribution, and thereby to contribute to a better understanding of both Earth structure and noise generation. First, we develop an inversion strategy based on a 2D finite-difference code using adjoint techniques. To enable a joint inversion for noise sources and Earth structure, we investigate the following aspects: i) the capability of different misfit functionals to image wave speed anomalies and source distribution and ii) possible source-structure trade-offs, especially to what extent unresolvable structure can be mapped into the inverted noise source distribution and vice versa. In anticipation of real-data applications, we present an extension of the open-source waveform modelling and inversion package Salvus ( It allows us to compute correlation functions in 3D media with heterogeneous noise sources at the surface and the corresponding sensitivity kernels for the distribution of noise sources and Earth structure. By studying the effect of noise sources on correlation functions in 3D, we validate the aforementioned inversion strategy and prepare the

  2. Drug-induced renal injury

    Drugs can cause acute renal failure by causing pre-renal, intrinsic or post-renal toxicity. Pre-renal ... incidence of drug dose adjustment in renal impairment in the SAMJ. ... Fever, haemolytic anaemia, thrombocytopenia, renal impairment and.

  3. Tera-sample-per-second Real-time Waveform Digitizer

    Han, Y; Jalali, B; Han, Yan; Boyraz, Ozdal; Jalali, Bahram


    We demonstrate a real-time transient waveform digitizer with a record 1 TSa/s (Tera-Sample/sec) sampling rate. This is accomplished by using a photonic time stretch preprocessor which slows down the electrical waveform before it is captured by an electronic digitizer.

  4. An Overview of Radar Waveform Optimization for Target Detection

    Wang Lulu


    Full Text Available An optimal waveform design method that fully employs the knowledge of the target and the environment can further improve target detection performance, thus is of vital importance to research. In this paper, methods of radar waveform optimization for target detection are reviewed and summarized and provide the basis for the research.

  5. Automated multimode inversion of surface and S waveforms

    Lebedev, Sergei; Nolet, Guust; Meier, Thomas; Hilst, R.D. van der


    Inversion of the surface, S, and multiple-S waveforms is an effective means of constraining the structure of the upper mantle, including the transition zone. Exploiting the resolving power of the enormous volume of presently available data requires efficiency of data processing and waveform modellin

  6. Analysis of a Proposed Two-Frequency Radar Waveform


    Rice and Dugundji . The waveform at the Input of the detector is u(t) -§ cn cos (UM: + f^) (1) A frequency q called the "midband frequency"is selected...Analysis of Random Noise," Bell Systi Technical Journal. Vol 23, p 81, 1944. 11. J. Dugundji , "Bivelopes and Pre-Envelopes of Real Waveforms," IRE

  7. Method and apparatus for resonant frequency waveform modulation

    Taubman, Matthew S [Richland, WA


    A resonant modulator device and process are described that provide enhanced resonant frequency waveforms to electrical devices including, e.g., laser devices. Faster, larger, and more complex modulation waveforms are obtained than can be obtained by use of conventional current controllers alone.

  8. Waveform Selectivity at the Same Frequency

    Wakatsuchi, Hiroki; Rushton, Jeremiah J; Gao, Fei; Kim, Sanghoon; Sievenpiper, Daniel F


    Electromagnetic properties depend on the composition of materials, i.e. either angstrom scales of molecules or, for metamaterials, subwavelength periodic structures. Each material behaves differently in accordance with the frequency of an incoming electromagnetic wave due to the frequency dispersion or the resonance of the periodic structures. This indicates that if the frequency is fixed, the material always responds in the same manner unless it has nonlinearity. However, such nonlinearity is controlled by the magnitude of the incoming wave or other bias. Therefore, it is difficult to distinguish different incoming waves at the same frequency. Here we present a new concept of circuit-based metasurfaces to selectively absorb or transmit specific types of waveforms even at the same frequency. The metasurfaces, integrated with schottky diodes as well as either capacitors or inductors, selectively absorb short or long pulses, respectively. The two types of the circuit elements are then combined to absorb or tran...

  9. Direct Waveform Inversion by Iterative Inverse Propagation

    Schlottmann, R B


    Seismic waves are the most sensitive probe of the Earth's interior we have. With the dense data sets available in exploration, images of subsurface structures can be obtained through processes such as migration. Unfortunately, relating these surface recordings to actual Earth properties is non-trivial. Tomographic techniques use only a small amount of the information contained in the full seismogram and result in relatively low resolution images. Other methods use a larger amount of the seismogram but are based on either linearization of the problem, an expensive statistical search over a limited range of models, or both. We present the development of a new approach to full waveform inversion, i.e., inversion which uses the complete seismogram. This new method, which falls under the general category of inverse scattering, is based on a highly non-linear Fredholm integral equation relating the Earth structure to itself and to the recorded seismograms. An iterative solution to this equation is proposed. The res...

  10. Facies Constrained Elastic Full Waveform Inversion

    Zhang, Z.


    Current efforts to utilize full waveform inversion (FWI) as a tool beyond acoustic imaging applications, for example for reservoir analysis, face inherent limitations on resolution and also on the potential trade-off between elastic model parameters. Adding rock physics constraints does help to mitigate these issues. However, current approaches to add such constraints are based on averaged type rock physics regularization terms. Since the true earth model consists of different facies, averaging over those facies naturally leads to smoothed models. To overcome this, we propose a novel way to utilize facies based constraints in elastic FWI. A so-called confidence map is calculated and updated at each iteration of the inversion using both the inverted models and the prior information. The numerical example shows that the proposed method can reduce the cross-talks and also can improve the resolution of inverted elastic properties.

  11. Integrating Biosystem Models Using Waveform Relaxation

    Stephen Baigent


    Full Text Available Modelling in systems biology often involves the integration of component models into larger composite models. How to do this systematically and efficiently is a significant challenge: coupling of components can be unidirectional or bidirectional, and of variable strengths. We adapt the waveform relaxation (WR method for parallel computation of ODEs as a general methodology for computing systems of linked submodels. Four test cases are presented: (i a cascade of unidirectionally and bidirectionally coupled harmonic oscillators, (ii deterministic and stochastic simulations of calcium oscillations, (iii single cell calcium oscillations showing complex behaviour such as periodic and chaotic bursting, and (iv a multicellular calcium model for a cell plate of hepatocytes. We conclude that WR provides a flexible means to deal with multitime-scale computation and model heterogeneity. Global solutions over time can be captured independently of the solution techniques for the individual components, which may be distributed in different computing environments.

  12. Synthetic tsunami waveform catalogs with kinematic constraints

    Baptista, Maria Ana; Miranda, Jorge Miguel; Matias, Luis; Omira, Rachid


    In this study we present a comprehensive methodology to produce a synthetic tsunami waveform catalogue in the northeast Atlantic, east of the Azores islands. The method uses a synthetic earthquake catalogue compatible with plate kinematic constraints of the area. We use it to assess the tsunami hazard from the transcurrent boundary located between Iberia and the Azores, whose western part is known as the Gloria Fault. This study focuses only on earthquake-generated tsunamis. Moreover, we assume that the time and space distribution of the seismic events is known. To do this, we compute a synthetic earthquake catalogue including all fault parameters needed to characterize the seafloor deformation covering the time span of 20 000 years, which we consider long enough to ensure the representability of earthquake generation on this segment of the plate boundary. The computed time and space rupture distributions are made compatible with global kinematic plate models. We use the tsunami empirical Green's functions to efficiently compute the synthetic tsunami waveforms for the dataset of coastal locations, thus providing the basis for tsunami impact characterization. We present the results in the form of offshore wave heights for all coastal points in the dataset. Our results focus on the northeast Atlantic basin, showing that earthquake-induced tsunamis in the transcurrent segment of the Azores-Gibraltar plate boundary pose a minor threat to coastal areas north of Portugal and beyond the Strait of Gibraltar. However, in Morocco, the Azores, and the Madeira islands, we can expect wave heights between 0.6 and 0.8 m, leading to precautionary evacuation of coastal areas. The advantages of the method are its easy application to other regions and the low computation effort needed.

  13. Design of a 9-loop quasi-exponential waveform generator.

    Banerjee, Partha; Shukla, Rohit; Shyam, Anurag


    We know in an under-damped L-C-R series circuit, current follows a damped sinusoidal waveform. But if a number of sinusoidal waveforms of decreasing time period, generated in an L-C-R circuit, be combined in first quarter cycle of time period, then a quasi-exponential nature of output current waveform can be achieved. In an L-C-R series circuit, quasi-exponential current waveform shows a rising current derivative and thereby finds many applications in pulsed power. Here, we have described design and experiment details of a 9-loop quasi-exponential waveform generator. In that, design details of magnetic switches have also been described. In the experiment, output current of 26 kA has been achieved. It has been shown that how well the experimentally obtained output current profile matches with the numerically computed output.

  14. Renal failure (chronic)

    Clase, Catherine


    Chronic renal failure is characterised by a gradual and sustained decline in renal clearance or glomerular filtration rate (GFR). Continued progression of renal failure will lead to renal function too low to sustain healthy life. In developed countries, such people will be offered renal replacement therapy in the form of dialysis or renal transplantation. Requirement for dialysis or transplantation is termed end-stage renal disease (ESRD).Diabetes, glomerulonephritis, hypertension, pyelone...

  15. On the accuracy and precision of numerical waveforms: Effect of waveform extraction methodology

    Chu, Tony; Kumar, Prayush; Pfeiffer, Harald P; Boyle, Michael; Hemberger, Daniel A; Kidder, Lawrence E; Scheel, Mark A; Szilagyi, Bela


    We present a new set of 95 numerical relativity simulations of non-precessing binary black holes (BBHs). The simulations sample comprehensively both black-hole spins up to spin magnitude of 0.9, and cover mass ratios 1 to 3. The simulations cover on average 24 inspiral orbits, plus merger and ringdown, with low initial orbital eccentricities $e<10^{-4}$. A subset of the simulations extends the coverage of non-spinning BBHs up to mass ratio $q=10$. Gravitational waveforms at asymptotic infinity are computed with two independent techniques, extrapolation, and Cauchy characteristic extraction. An error analysis based on noise-weighted inner products is performed. We find that numerical truncation error, error due to gravitational wave extraction, and errors due to the finite length of the numerical waveforms are of similar magnitude, with gravitational wave extraction errors somewhat dominating at noise-weighted mismatches of $\\sim 3\\times 10^{-4}$. This set of waveforms will serve to validate and improve ali...

  16. B-Mode and pulsed Doppler sonography of kidney in healthy sheep according to age

    Bianca P. Santarosa


    Full Text Available Abstract: There is no standardization in the literature of kidney length in sheep at different ages, as there are few studies about the access with the Doppler triplex ultrasound for the renal vascularization in this species. Eighty healthy sheep of three age groups of Ile de France and White Dorper breed were used: 20 lambs, 30 yearlings and 30 adults (8 rams and 22 ewes. Renal healthiness of the animals was confirmed by serum biochemical tests of urea and creatinine, and by observation of renal architecture with conventional ultrasound, besides measurement of vital parameters. A portable ultrasound (My LabTM30 Vet Gold Esaote®, Esaote Healthcare device was used, with a convex transducer with 3.5MHz frequency. After identification of the kidneys in two-dimensional mode, the measurement of length in the sagittal section was performed in all sheep (n=80. Then color Doppler was activated for visualization of renal and interlobar arteries of the right kidney, and the resistivity index (RI of the yearlings (n=30 and ewes (n=22 was measured. Biochemical tests remained within normal limits and renal architecture was preserved. The values of the right and left renal length were different between the groups, increasing with age (4.34cm and 4.31cm in lambs; 6.08cm and 6.23cm in yearlings; 7.57cm and 7.37cm in adults, respectively. Median values of RI of the renal artery were statistically different (p<0.05 between the groups of yearlings (0.57 and ewes (0.52. The median RI of the interlobar artery was similar in yearlings (0.58 and ewes (0.54.

  17. Pulsed-wave Doppler ultrasonographic evaluation of hepatic vein in dogs with tricuspid regurgitation

    Kim, Jaehwan; Kim, Soyoung


    This study was performed to identify the relationships between hepatic vein (HV) measurements, including flow velocity and waveform, using pulsed-wave (PW) Doppler ultrasonography, and the severity of tricuspid regurgitation (TR) in dogs. The study included 22 dogs with TR and 7 healthy dogs. The TR group was subdivided into 3 groups according to TR jet profile obtained by echocardiography. The hepatic venous waveform was obtained and classified into 3 types. A variety of HV measurements, including the maximal velocities of the atrial systolic, systolic (S), end ventricular systolic, and diastolic (D) waves and the ratio of the S- and D- wave velocities (S/D ratio), were acquired. TR severity was significantly correlated with the S- (r = −0.380, p = 0.042) and D- (r = 0.468, p = 0.011) wave velocities and the S/D ratio (r = −0.747, p < 0.001). Receiver operating characteristic curve analysis revealed the highest sensitivity and specificity for the S/D ratio (89% and 75%, respectively) at a threshold of 0.97 with excellent accuracy (AUC = 0.911, p < 0.001). In conclusion, PW Doppler ultrasonography of the HV can be used to identify the presence of significant TR and to classify TR severity in dogs. PMID:27515264

  18. Real-time Doppler-based arterial vascular impedance and peripheral pressure-flow loops: a pilot study.

    Thiele, Robert H; Bartels, Karsten; Esper, Stephen; Ikeda, Keita; Gan, Tong-Joo


    Arterial pressure-flow loops and vascular impedance provide additional data that could be used to assess the hemodynamic effects of therapeutic interventions in anesthetized patients. To evaluate the utility of such an approach, the authors sought to design a device that combines flow waveforms from an esophageal Doppler probe and pressure waveforms from a peripheral artery to produce real-time pressure-flow loops and estimates of arterial vascular impedance. Prospective, cohort study. Single center, university-based teaching hospital. Patients undergoing surgery in whom the attending anesthesiologist had opted to place an esophageal Doppler probe and a peripheral arterial catheter for hemodynamic monitoring. This was a non-interventional study designed to record pressure-flow loops and arterial vascular impedance intraoperatively using a novel, noninvasive device. Pressure-flow loops and arterial vascular impedance were measured noninvasively using radial artery pressure and descending thoracic aorta flow waveforms in real time. Real-time arterial vascular impedance and peripheral pressure-volume loops can be determined using available monitoring devices. Technical feasibility of this technology in patients is a crucial first step to permit meaningful evaluation of the clinical value of this approach for accurate determination of complex hemodynamic indices and, eventually, improvement of outcomes. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Acute Page kidney following renal allograft biopsy: a complication requiring early recognition and treatment.

    Chung, J; Caumartin, Y; Warren, J; Luke, P P W


    The acute Page kidney phenomenon occurs as a consequence of external compression of the renal parenchyma leading to renal ischemia and hypertension. Between January 2000 and September 2007, 550 kidney transplants and 518 ultrasound-guided kidney biopsies were performed. During that time, four recipients developed acute oligo-anuria following ultrasound-guided allograft biopsy. Emergent doppler-ultrasounds were performed demonstrating absence of diastolic flow as well as a sub-capsular hematoma of the kidney. Prompt surgical exploration with allograft capsulotomy was performed in all cases. Immediately after capsulotomy, intraoperative Doppler study demonstrated robust return of diastolic flow. Three patients maintained good graft function, and one kidney was lost due to acute antibody-mediated rejection. We conclude that postbiopsy anuria associated with a subcapsular hematoma and acute absence of diastolic flow on doppler ultrasound should be considered pathognomonic of APK. All renal transplant specialists should be able to recognize this complication, because immediate surgical decompression can salvage the allograft.

  20. Kinematic Seismic Rupture Parameters from a Doppler Analysis

    Caldeira, Bento; Bezzeghoud, Mourad; Borges, José F.


    The radiation emitted from extended seismic sources, mainly when the rupture spreads in preferred directions, presents spectral deviations as a function of the observation location. This aspect, unobserved to point sources, and named as directivity, are manifested by an increase in the frequency and amplitude of seismic waves when the rupture occurs in the direction of the seismic station and a decrease in the frequency and amplitude if it occurs in the opposite direction. The model of directivity that supports the method is a Doppler analysis based on a kinematic source model of rupture and wave propagation through a structural medium with spherical symmetry [1]. A unilateral rupture can be viewed as a sequence of shocks produced along certain paths on the fault. According this model, the seismic record at any point on the Earth's surface contains a signature of the rupture process that originated the recorded waveform. Calculating the rupture direction and velocity by a general Doppler equation, - the goal of this work - using a dataset of common time-delays read from waveforms recorded at different distances around the epicenter, requires the normalization of measures to a standard value of slowness. This normalization involves a non-linear inversion that we solve numerically using an iterative least-squares approach. The evaluation of the performance of this technique was done through a set of synthetic and real applications. We present the application of the method at four real case studies, the following earthquakes: Arequipa, Peru (Mw = 8.4, June 23, 2001); Denali, AK, USA (Mw = 7.8; November 3, 2002); Zemmouri-Boumerdes, Algeria (Mw = 6.8, May 21, 2003); and Sumatra, Indonesia (Mw = 9.3, December 26, 2004). The results obtained from the dataset of the four earthquakes agreed, in general, with the values presented by other authors using different methods and data. [1] Caldeira B., Bezzeghoud M, Borges JF, 2009; DIRDOP: a directivity approach to determining

  1. Renale Osteopathie

    Horn S


    Die renale Osteopathie umfaßt Erkrankungen des Knochens, die bei Patienten mit chronischen Nierenerkrankungen auftreten, wie den sekundären bzw. tertiären Hyperparathyreoidismus, die adynamische Knochenerkrankung und die Osteopathie nach Nierentransplantation. Durch die Identifikation des Kalzium-Sensing-Rezeptors bzw. des Vitamin D-Rezeptors hat sich unser Verständnis der Zusammenhänge in den letzten Jahren erheblich verbessert. Neue Medikamente versprechen effizientere Prophylaxe- und Thera...

  2. Renale Knochenerkrankungen

    Mayer G


    Full Text Available Störungen des Mineral- und Knochenstoffwechsels sind bei fast allen Patienten mit chronischen Nierenerkrankungen anzutreffen. Pathogenetisch spielt eine Neigung zur Phosphatretention bei einer Reduktion der glomerulären Filtrationsrate die zentrale Rolle. Neben typischen, aber sehr variablen Veränderungen der Knochenstruktur (renale Osteopathie besteht auch eine sehr enge Assoziation zwischen diesen Störungen und dem massiv erhöhten kardiovaskulären Risiko der Patienten.




    Full Text Available A study of 50 cases was conducted to evaluate the role of Colour Doppler imaging in pregnancy induced hypertension with women over 28 weeks of gestation, the initial scan was performed immediately after the diagnosis of PIH to avoid any influence of treatment on Doppler evaluation. This study was aimed to analyze the blood flow in umbilical artery, maternal uterine artery & fetal middle cerebral artery using Doppler ultrasound.

  4. Obesity and renal hemodynamics

    Bosma, R. J.; Krikken, J. A.; van der Heide, J. J. Homan; de Jong, P. E.; Navis, G. J.


    Obesity is a risk factor for renal damage in native kidney disease and in renal transplant recipients. Obesity is associated with several renal risk factors such as hypertension and diabetes that may convey renal risk, but obesity is also associated with an unfavorable renal hemodynamic profile

  5. Obesity and renal hemodynamics

    Bosma, R. J.; Krikken, J. A.; van der Heide, J. J. Homan; de Jong, P. E.; Navis, G. J.


    Obesity is a risk factor for renal damage in native kidney disease and in renal transplant recipients. Obesity is associated with several renal risk factors such as hypertension and diabetes that may convey renal risk, but obesity is also associated with an unfavorable renal hemodynamic profile inde

  6. Emboli detection using the Doppler ultrasound technique

    WANG Yuanyuan; CHEN Xi; ZHANG Yu; WANG Weiqi


    Embolic detection is very important to the early diagnosis of vessel disease. The Doppler ultrasound technique is one of the common methods to detect the emboli non-invasively. When the emboli pass through the sample volume of the Doppler ultrasound instrument, there exist high intensity transient Doppler signals. Thus the emboli can be detected directly from the variation of Doppler signal amplitude. Since there may be some disturbance in the system, this general detection method has great limitation. To improve the accuracy of emboli auto-detection, several novel methods are studied to obtain the sensitive characteristic of the emboli signals using the new signal processing theories.

  7. Bilateral native kidney neoplasia detected by ultrasound in functionning renal allograft recipient.

    Noce, Annalisa; Iaria, Giuseppe; Durante, Olga; Sforza, Daniele; Canale, Maria Paola; Di Villahermosa, Simone Manca; Castagnola, Veronica; Tisone, Giuseppe; Di Daniele, Nicola


    We report the case of bilateral renal clear cell carcinoma in the native kidney, occurring fouryears after renal transplantation. Renal Doppler duplex sonography revealed large solid bilateral neoformation. Total-body computed tomography confirmed the presence of bilateral kidney lesions and also showed the presence of concomitant gross dyscariocinetic lesion of left hemotorax. The patient underwent bilateral native nephrectomy and the histological diagnosis was renal cell carcinoma. Subsequent left upper lobectomy revealed necrotic keratinizing squamous cell carcinoma. Then, the patients was switched tacrolimus to everolimus treatment and mycophenolate mofetil was reduced.

  8. Simulation of Full-Waveform Laser Altimeter Echowaveform

    Lv, Y.; Tong, X. H.; Liu, S. J.; Xie, H.; Luan, K. F.; Liu, J.


    Change of globe surface height is an important factor to study human living environment. The Geoscience Laser Altimeter System (GLAS) on ICESat is the first laser-ranging instrument for continuous global observations of the Earth. In order to have a comprehensive understanding of full-waveform laser altimeter, this study simulated the operating mode of ICESat and modeled different terrains' (platform terrain, slope terrain, and artificial terrain) echo waveforms based on the radar equation. By changing the characteristics of the system and the targets, numerical echo waveforms can be achieved. Hereafter, we mainly discussed the factors affecting the amplitude and size (width) of the echoes. The experimental results implied that the slope of the terrain, backscattering coefficient and reflectivity, target height, target position in the footprint and area reacted with the pulse all can affect the energy distribution of the echo waveform and the receiving time. Finally, Gaussian decomposition is utilized to decompose the echo waveform. From the experiment, it can be noted that the factors which can affect the echo waveform and by this way we can know more about large footprint full-waveform satellite laser altimeter.

  9. Design and implementation of a hospital wide waveform capture system.

    Blum, James M; Joo, Heyon; Lee, Henry; Saeed, Mohammed


    The use of telemetry and invasive monitoring is exceptionally common in modern healthcare. To date the vast majority of this information is not stored for more than a brief duration on the local monitor. This prohibits extensive investigation into waveform data. We describe a system to collect such data in a quaternary care facility. Using standardized "packet sniffing" technology along with routine manual documentation, we reverse engineered the Unity network protocol used to transmit waveform data across the University of Michigan mission critical monitor network. Data was subsequently captured using a proprietary piece of software writing waveform data to local disks. Nightly, this data is post-processed using data from the admit-discharge-transfer system into individual patient waveforms for the day regardless of location. Over a 10 month period, over 2,785 individual patients had a total of 65,112 waveforms captured 15,978 from the operating rooms and 49,134 from the ICUs. The average OR case collected over 11 MB of data. The average single day data collection consisted of 8.6 GB of data. Entire hospital waveform data collection is possible using internally developed software enabling research on waveform data with minimal technical burden. Further research is required to determine the long-term storage and processing of such data.

  10. Generation of correlated finite alphabet waveforms using gaussian random variables

    Jardak, Seifallah


    Correlated waveforms have a number of applications in different fields, such as radar and communication. It is very easy to generate correlated waveforms using infinite alphabets, but for some of the applications, it is very challenging to use them in practice. Moreover, to generate infinite alphabet constant envelope correlated waveforms, the available research uses iterative algorithms, which are computationally very expensive. In this work, we propose simple novel methods to generate correlated waveforms using finite alphabet constant and non-constant-envelope symbols. To generate finite alphabet waveforms, the proposed method map the Gaussian random variables onto the phase-shift-keying, pulse-amplitude, and quadrature-amplitude modulation schemes. For such mapping, the probability-density-function of Gaussian random variables is divided into M regions, where M is the number of alphabets in the corresponding modulation scheme. By exploiting the mapping function, the relationship between the cross-correlation of Gaussian and finite alphabet symbols is derived. To generate equiprobable symbols, the area of each region is kept same. If the requirement is to have each symbol with its own unique probability, the proposed scheme allows us that as well. Although, the proposed scheme is general, the main focus of this paper is to generate finite alphabet waveforms for multiple-input multiple-output radar, where correlated waveforms are used to achieve desired beampatterns. © 2014 IEEE.

  11. Source-independent elastic waveform inversion using a logarithmic wavefield

    Choi, Yun Seok


    The logarithmic waveform inversion has been widely developed and applied to some synthetic and real data. In most logarithmic waveform inversion algorithms, the subsurface velocities are updated along with the source estimation. To avoid estimating the source wavelet in the logarithmic waveform inversion, we developed a source-independent logarithmic waveform inversion algorithm. In this inversion algorithm, we first normalize the wavefields with the reference wavefield to remove the source wavelet, and then take the logarithm of the normalized wavefields. Based on the properties of the logarithm, we define three types of misfit functions using the following methods: combination of amplitude and phase, amplitude-only, and phase-only. In the inversion, the gradient is computed using the back-propagation formula without directly calculating the Jacobian matrix. We apply our algorithm to noise-free and noise-added synthetic data generated for the modified version of elastic Marmousi2 model, and compare the results with those of the source-estimation logarithmic waveform inversion. For the noise-free data, the source-independent algorithms yield velocity models close to true velocity models. For random-noise data, the source-estimation logarithmic waveform inversion yields better results than the source-independent method, whereas for coherent-noise data, the results are reversed. Numerical results show that the source-independent and source-estimation logarithmic waveform inversion methods have their own merits for random- and coherent-noise data. © 2011.

  12. Adaptive Prony method for waveform distortion detection in power systems

    Bracale, A.; Carpinelli, G. [Electrical Engineering Department, University of Napoli, Via Claudio 21, 80125 Napoli (Italy); Caramia, P. [Industrial Engineering Department, University of Cassino (Italy)


    IEC Standards characterize the waveform distortions in power systems with the amplitudes of harmonic and interharmonic groupings (subgroups and groups) calculated by using the waveform spectral components obtained with a 5 Hz frequency resolution DFT. In some cases the power system waveforms are characterized by means of spectral signal components that the DFT with 5 Hz frequency resolution is unable to capture with sufficient accuracy. In this paper a new Prony method is proposed to calculate the harmonic and interharmonic subgroups. This method is based on an adaptive technique that acts with the aim of minimizing the mean square relative error of signal estimation. (author)

  13. Compressive full-waveform LIDAR with low-cost sensor

    Yang, Weiyi; Ke, Jun


    Full-waveform LiDAR is a method that digitizes the complete waveform of backscattered pulses to obtain range information of multi-targets. To avoid expensive sensors in conventional full-waveform LiDAR system, a new system based on compressive sensing method is presented in this paper. The non-coherent continuous-wave laser is modulated by electro-optical modulator with pseudo-random sequences. A low-bandwidth detector and a low-bandwidth analog-digital converter are used to acquire the returned signal. OMP algorithm is employed to reconstruct the high resolution range information.

  14. Fast Prediction and Evaluation of Gravitational Waveforms Using Surrogate Models

    Scott E. Field


    Full Text Available We propose a solution to the problem of quickly and accurately predicting gravitational waveforms within any given physical model. The method is relevant for both real-time applications and more traditional scenarios where the generation of waveforms using standard methods can be prohibitively expensive. Our approach is based on three offline steps resulting in an accurate reduced order model in both parameter and physical dimensions that can be used as a surrogate for the true or fiducial waveform family. First, a set of m parameter values is determined using a greedy algorithm from which a reduced basis representation is constructed. Second, these m parameters induce the selection of m time values for interpolating a waveform time series using an empirical interpolant that is built for the fiducial waveform family. Third, a fit in the parameter dimension is performed for the waveform’s value at each of these m times. The cost of predicting L waveform time samples for a generic parameter choice is of order O(mL+mc_{fit} online operations, where c_{fit} denotes the fitting function operation count and, typically, m≪L. The result is a compact, computationally efficient, and accurate surrogate model that retains the original physics of the fiducial waveform family while also being fast to evaluate. We generate accurate surrogate models for effective-one-body waveforms of nonspinning binary black hole coalescences with durations as long as 10^{5}M, mass ratios from 1 to 10, and for multiple spherical harmonic modes. We find that these surrogates are more than 3 orders of magnitude faster to evaluate as compared to the cost of generating effective-one-body waveforms in standard ways. Surrogate model building for other waveform families and models follows the same steps and has the same low computational online scaling cost. For expensive numerical simulations of binary black hole coalescences, we thus anticipate extremely large speedups in

  15. General Dynamic (GD) Launch Waveform On-Orbit Performance Report

    Briones, Janette C.; Shalkhauser, Mary Jo


    The purpose of this report is to present the results from the GD SDR on-orbit performance testing using the launch waveform over TDRSS. The tests include the evaluation of well-tested waveform modes, the operation of RF links that are expected to have high margins, the verification of forward return link operation (including full duplex), the verification of non-coherent operational models, and the verification of radio at-launch operational frequencies. This report also outlines the launch waveform tests conducted and comparisons to the results obtained from ground testing.

  16. Ultrawideband coherent noise lidar range-Doppler imaging and signal processing by use of spatial-spectral holography in inhomogeneously broadened absorbers.

    Li, Youzhi; Hoskins, Alan; Schlottau, Friso; Wagner, Kelvin H; Embry, Carl; Babbitt, William Randall


    We introduce a new approach to coherent lidar range-Doppler sensing by utilizing random-noise illuminating waveforms and a quantum-optical, parallel sensor based on spatial-spectral holography (SSH) in a cryogenically cooled inhomogeneously broadened absorber (IBA) crystal. Interference between a reference signal and the lidar return in the spectrally selective absorption band of the IBA is used to sense the lidar returns and perform the front-end range-correlation signal processing. Modulating the reference by an array of Doppler compensating frequency shifts enables multichannel Doppler filtering. This SSH sensor performs much of the postdetection signal processing, increases the lidar system sensitivity through range-correlation gain before detection, and is capable of not only Doppler processing but also parallel multibeam reception using the high-spatial resolution of the IBA crystals. This approach permits the use of ultrawideband, high-power, random-noise, cw lasers as ranging waveforms in lidar systems instead of highly stabilized, injection-seeded, and amplified pulsed or modulated laser sources as required by most conventional coherent lidar systems. The capabilities of the IBA media for many tens of gigahertz bandwidth and resolution in the 30-300 kHz regime, while using either a pseudo-noise-coded waveform or just a high-power, noisy laser with a broad linewidth (e.g., a truly random noise lidar) may enable a new generation of improved lidar sensors and processors. Preliminary experimental demonstrations of lidar ranging and simulation on range-Doppler processing are presented.

  17. Analysis of the Sensitivity and Specificity of Noninvasive Imaging Tests for the Diagnosis of Renal Artery Stenosis

    Borelli, Flavio Antonio de Oliveira, E-mail:; Pinto, Ibraim M. F.; Amodeo, Celso; Smanio, Paola E. P.; Kambara, Antonio M.; Petisco, Ana Claudia G.; Moreira, Samuel M.; Paiva, Ricardo Calil; Lopes, Hugo Belotti; Sousa, Amanda G. M. R. [Instituto Dante Pazzanese de Cardiologia, São Paulo, SP (Brazil)


    Aging and atherosclerosis are related to renovascular hypertension in elderly individuals. Regardless of comorbidities, renal artery stenosis is itself an important cause of cardiovascular morbidity and mortality. To define the sensitivity, specificity, positive predictive value, and negative predictive value of noninvasive imaging tests used in the diagnosis of renal artery stenosis. In a group of 61 patients recruited, 122 arteries were analized, thus permitting the definition of sensitivity, specificity, and the relative contribution of each imaging study performed (Doppler, scintigraphy and computed tomographic angiography in comparison to renal arteriography). The mean age was 65.43 years (standard deviation: 8.7). Of the variables related to the study population that were compared to arteriography, two correlated with renal artery stenosis, renal dysfunction and triglycerides. The median glomerular filtration rate was 52.8 mL/min/m{sup 2}. Doppler showed sensitivity of 82.90%, specificity of 70%, a positive predictive value of 85% and negative predictive value of 66.70%. For tomography, sensitivity was 66.70%, specificity 80%, positive predictive value 87.50% and negative predictive value 55.20%. With these findings, we could identify the imaging tests that best detected stenosis. Tomography and Doppler showed good quality and efficacy in the diagnosis of renal artery stenosis, with Doppler having the advantage of not requiring the use of contrast medium for the assessment of a disease that is common in diabetics and is associated with renal dysfunction and severe left ventricular dysfunction.

  18. Bilateral Renal Mass-Renal Disorder: Tuberculosis

    Ozlem Tiryaki


    Full Text Available A 30-year-old woman has presented complaining of weakness and fatigue to her primary care physician. The renal sonography is a routine step in the evaluation of new onset renal failure. When the renal masses have been discovered by sonography in this setting, the functional imaging may be critical. We reported a case about bilateral renal masses in a young female patient with tuberculosis and renal insufficiency. Magnetic resonance (MR has revealed the bilateral renal masses in patient, and this patient has been referred to our hospital for further management. The patient’s past medical and surgical history was unremarkable.

  19. Distal renal tubular acidosis

    Renal tubular acidosis - distal; Renal tubular acidosis type I; Type I RTA; RTA - distal; Classical RTA ... excreting it into the urine. Distal renal tubular acidosis (Type I RTA) is caused by a defect ...

  20. Proximal renal tubular acidosis

    Renal tubular acidosis - proximal; Type II RTA; RTA - proximal; Renal tubular acidosis type II ... by alkaline substances, mainly bicarbonate. Proximal renal tubular acidosis (Type II RTA) occurs when bicarbonate is not ...

  1. Full Waveform Inversion Using Nonlinearly Smoothed Wavefields

    Li, Y.


    The lack of low frequency information in the acquired data makes full waveform inversion (FWI) conditionally converge to the accurate solution. An initial velocity model that results in data with events within a half cycle of their location in the observed data was required to converge. The multiplication of wavefields with slightly different frequencies generates artificial low frequency components. This can be effectively utilized by multiplying the wavefield with itself, which is nonlinear operation, followed by a smoothing operator to extract the artificially produced low frequency information. We construct the objective function using the nonlinearly smoothed wavefields with a global-correlation norm to properly handle the energy imbalance in the nonlinearly smoothed wavefield. Similar to the multi-scale strategy, we progressively reduce the smoothing width applied to the multiplied wavefield to welcome higher resolution. We calculate the gradient of the objective function using the adjoint-state technique, which is similar to the conventional FWI except for the adjoint source. Examples on the Marmousi 2 model demonstrate the feasibility of the proposed FWI method to mitigate the cycle-skipping problem in the case of a lack of low frequency information.

  2. Full Waveform Inversion of Solar Interior Flows

    Hanasoge, Shravan M


    The inference of flows of material in the interior of the Sun is a subject of major interest in helioseismology. Here we apply techniques of Full Waveform Inversion (FWI) to synthetic data to test flow inversions. In this idealized setup, we do not model seismic realization noise, training the focus entirely on the problem of whether a chosen supergranulation flow model can be seismically recovered. We define the misfit functional as a sum of L_2 norm deviations in travel times between prediction and observation, as measured using short-distance f and p_1 filtered and large-distance unfiltered $p$ modes. FWI allows for the introduction of measurements of choice and iteratively improving the background model, while monitoring the evolution of the misfit in all desired categories. Although the misfit is seen to uniformly reduce in all categories, convergence to the true model is very slow, possibly because it is trapped in a local minimum. The primary source of error is inaccurate depth localization, which, owi...

  3. Tsunami waveform inversion by adjoint methods

    Pires, Carlos; Miranda, Pedro M. A.


    An adjoint method for tsunami waveform inversion is proposed, as an alternative to the technique based on Green's functions of the linear long wave model. The method has the advantage of being able to use the nonlinear shallow water equations, or other appropriate equation sets, and to optimize an initial state given as a linear or nonlinear function of any set of free parameters. This last facility is used to perform explicit optimization of the focal fault parameters, characterizing the initial sea surface displacement of tsunamigenic earthquakes. The proposed methodology is validated with experiments using synthetic data, showing the possibility of recovering all relevant details of a tsunami source from tide gauge observations, providing that the adjoint method is constrained in an appropriate manner. It is found, as in other methods, that the inversion skill of tsunami sources increases with the azimuthal and temporal coverage of assimilated tide gauge stations; furthermore, it is shown that the eigenvalue analysis of the Hessian matrix of the cost function provides a consistent and useful methodology to choose the subset of independent parameters that can be inverted with a given dataset of observations and to evaluate the error of the inversion process. The method is also applied to real tide gauge series, from the tsunami of the February 28, 1969, Gorringe Bank earthquake, suggesting some reasonable changes to the assumed focal parameters of that event. It is suggested that the method proposed may be able to deal with transient tsunami sources such as those generated by submarine landslides.

  4. Waveform Analysis of AE in Composites

    Prosser, William H.


    Advanced, waveform based acoustic emission (AE) techniques have been developed to evaluate damage mechanisms in the testing of composite materials. This approach, more recently referred to as Modal AE, provides an enhanced capability to discriminate and eliminate noise signals from those generated by damage mechanisms. Much more precise source location can also be obtained in comparison to conventional, threshold crossing arrival time determination techniques. Two successful examples of the application of Modal AE are presented in this work. In the first, the initiation of transverse matrix cracking in cross-ply, tensile coupons was monitored. In these tests, it was documented that the same source mechanism, matrix cracking, can produce widely different AE signal amplitudes dependent on laminate stacking sequence and thickness. These results, taken together with well known propagation effects of attenuation and dispersion of AE signals in composite laminates, cast further doubt on the validity of simple amplitude or amplitude distribution analysis for AE source determination. For the second example, delamination propagation in composite ring specimens was monitored. Pressurization of these composite rings is used to simulate the stresses in a composite rocket motor case. AE signals from delamination propagation were characterized by large amplitude flexural plate mode components which have long signal durations because of the large dispersion of this mode.

  5. Inversion method for initial tsunami waveform reconstruction

    V. V. Voronin


    Full Text Available This paper deals with the application of r-solution method to recover the initial tsunami waveform in a tsunami source area by remote water-level measurements. Wave propagation is considered within the scope of a linear shallow-water theory. An ill-posed inverse problem is regularized by means of least square inversion using a truncated SVD approach. The properties of obtained solution are determined to a large extent by the properties of an inverse operator, which were numerically investigated. The method presented allows one to control instability of the numerical solution and to obtain an acceptable result in spite of ill-posedness of the problem. It is shown that the accuracy of tsunami source reconstruction strongly depends on the signal-to-noise ratio, the azimuthal coverage of recording stations with respect to the source area and bathymetric features along the wave path. The numerical experiments were carried out with synthetic data and various computational domains including a real bathymetry. The method proposed allows us to make a preliminary prediction of the efficiency of the inversion with a given set of the recording stations and to find out the most informative part of the existing observation system. This essential property of the method can prove to be useful in designing a monitoring system for tsunamis.

  6. Renal tuberculosis

    Džamić Zoran


    Full Text Available Tuberculosis is still a significant health problem in the world, mostly in developing countries. The special significance lies in immunocompromised patients, particularly those suffering from the HIV. Urogenital tuberculosis is one of the most common forms of extrapulmonary tuberculosis, while the most commonly involved organ is the kidney. Renal tuberculosis occurs by hematogenous dissemination of mycobacterium tuberculosis from a primary tuberculosis foci in the body. Tuberculosis is characterized by the formation of pathognomonic lesions in the tissues - granulomata. These granulomata may heal spontaneously or remain stable for years. In certain circumstances in the body associated with immunosuppression, the disease may be activated. Central caseous necrosis occurs within tuberculoma, leading to formation of cavities that destroy renal parenchyma. The process may gain access to the collecting system, forming the caverns. In this way, infection can be spread distally to renal pelvis, ureter and bladder. Scaring of tissue by tuberculosis process may lead to development of strictures of the urinary tract. The clinical manifestations are presented by nonspecific symptoms and signs, so tuberculosis can often be overlooked. Sterile pyuria is characteristic for urinary tuberculosis. Dysuric complaints, flank pain or hematuria may be presented in patients. Constitutional symptoms of fever, weight loss and night sweats are presented in some severe cases. Diagnosis is made by isolation of mycobacterium tuberculosis in urine samples, by cultures carried out on standard solid media optimized for mycobacterial growth. Different imaging studies are used in diagnostics - IVU, CT and NMR are the most important. Medical therapy is the main modality of tuberculosis treatment. The first line anti-tuberculosis drugs include isoniazid, rifampicin, pyrazinamide and ethambutol. Surgical treatment is required in some cases, to remove severely damaged kidney, if

  7. Renale Osteopathie

    Horn S


    Full Text Available Die renale Osteopathie umfaßt Erkrankungen des Knochens, die bei Patienten mit chronischen Nierenerkrankungen auftreten, wie den sekundären bzw. tertiären Hyperparathyreoidismus, die adynamische Knochenerkrankung und die Osteopathie nach Nierentransplantation. Durch die Identifikation des Kalzium-Sensing-Rezeptors bzw. des Vitamin D-Rezeptors hat sich unser Verständnis der Zusammenhänge in den letzten Jahren erheblich verbessert. Neue Medikamente versprechen effizientere Prophylaxe- und Therapiemöglichkeiten. Wir beeinflussen dadurch nicht nur die Morbidität und Lebensqualität, sondern auch die Mortalität unserer Patienten.

  8. Renal disease in pregnancy.

    Thorsen, Martha S; Poole, Judith H


    Anatomic and physiologic adaptations within the renal system during pregnancy are significant. Alterations are seen in renal blood flow and glomerular filtration, resulting in changes in normal renal laboratory values. When these normal renal adaptations are coupled with pregnancy-induced complications or preexisting renal dysfunction, the woman may demonstrate a reduction of renal function leading to an increased risk of perinatal morbidity and mortality. This article will review normal pregnancy adaptations of the renal system and discuss common pregnancy-related renal complications.

  9. Doppler tomography in fusion plasmas and astrophysics

    Salewski, Mirko; Geiger, B.; Heidbrink, W. W.


    Doppler tomography is a well-known method in astrophysics to image the accretion flow, often in the shape of thin discs, in compact binary stars. As accretion discs rotate, all emitted line radiation is Doppler-shifted. In fast-ion Dα (FIDA) spectroscopy measurements in magnetically confined plas...

  10. Radar Doppler Processing with Nonuniform Sampling.

    Doerry, Armin W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    Conventional signal processing to estimate radar Doppler frequency often assumes uniform pulse/sample spacing. This is for the convenience of t he processing. More recent performance enhancements in processor capability allow optimally processing nonuniform pulse/sample spacing, thereby overcoming some of the baggage that attends uniform sampling, such as Doppler ambiguity and SNR losses due to sidelobe control measures.

  11. Doppler tomography in fusion plasmas and astrophysics

    Salewski, M.; Geiger, B.; Heidbrink, W. W.; Jacobsen, A. S.; Korsholm, S. B.; Leipold, F.; Madsen, J.; Moseev, D.; Nielsen, S.K.; Rasmussen, J.; Stagner, L.; Steeghs, D.; Stejner, M.; Tardini, G.; Weiland, M.; ASDEX Upgrade team,


    Doppler tomography is a well-known method in astrophysics to image the accretion flow, often in the shape of thin discs, in compact binary stars. As accretion discs rotate, all emitted line radiation is Doppler-shifted. In fast-ion D-alpha (FIDA) spectroscopy measurements in magnetically confined pl

  12. A scalable, fast and multichannel arbitrary waveform generator

    Baig, Muhammad Tanveer; Wiese, Andreas; Heidbrink, Stefan; Ziolkowski, Michael; Wunderlich, Christof


    This article reports on development of a multichannel arbitrary waveform generator (MAWG), which simultaneously generates arbitrary voltage waveforms on 24 independent channels with a dynamic update rate of up to 25 Msps. A real-time execution of a single waveform and/or sequence of multiple waveforms in succession, with a user programmable arbitrary sequence order is provided under the control of a stand-alone sequencer circuit implemented using an FPGA. The device is operated using an internal clock and can be synced to other devices by means of the TTL pulses. The device can be used for output voltages in the range of up to +-9 V with a drift rate below +-10 uV/min and a maximum deviation less than +- 300 uVpp over a period of two hours.

  13. Multiscale Stategies in Automatic Image-Domain Waveform Tomography

    Yujin Liu; Zhenchun Li


    Multiscale strategies are very important in the successful application of waveform-based velocity inversion. The strategy that sequentially preceeds from long to short scale of velocity model, has been well developed in full waveform inversion (FWI) to solve the local mininum problem. In contrast, it’s not well understood in the image-domain waveform tomography (IWT), which back-projects incoherent waveform components of the common image gather into velocity updates. IWT is less prone to local minimum problem but tends to build long-scale model with low resolution. In order to build both long- and short-scale model by IWT, we discuss several multiscale strategies restricted in the image domain. The strategies include model reparameterization, objective function switching and gradient rescaling. Numerical tests on Marmsousi model and real data demonstrate that our proposed multiscale IWT is effective in buidling velocity model with wide wavenumber spectrum.

  14. Generation of correlated finite alphabet waveforms using gaussian random variables

    Ahmed, Sajid


    Various examples of methods and systems are provided for generation of correlated finite alphabet waveforms using Gaussian random variables in, e.g., radar and communication applications. In one example, a method includes mapping an input signal comprising Gaussian random variables (RVs) onto finite-alphabet non-constant-envelope (FANCE) symbols using a predetermined mapping function, and transmitting FANCE waveforms through a uniform linear array of antenna elements to obtain a corresponding beampattern. The FANCE waveforms can be based upon the mapping of the Gaussian RVs onto the FANCE symbols. In another example, a system includes a memory unit that can store a plurality of digital bit streams corresponding to FANCE symbols and a front end unit that can transmit FANCE waveforms through a uniform linear array of antenna elements to obtain a corresponding beampattern. The system can include a processing unit that can encode the input signal and/or determine the mapping function.

  15. Hybridizing Gravitationl Waveforms of Inspiralling Binary Neutron Star Systems

    Cullen, Torrey; LIGO Collaboration


    Gravitational waves are ripples in space and time and were predicted to be produced by astrophysical systems such as binary neutron stars by Albert Einstein. These are key targets for Laser Interferometer and Gravitational Wave Observatory (LIGO), which uses template waveforms to find weak signals. The simplified template models are known to break down at high frequency, so I wrote code that constructs hybrid waveforms from numerical simulations to accurately cover a large range of frequencies. These hybrid waveforms use Post Newtonian template models at low frequencies and numerical data from simulations at high frequencies. They are constructed by reading in existing Post Newtonian models with the same masses as simulated stars, reading in the numerical data from simulations, and finding the ideal frequency and alignment to ``stitch'' these waveforms together.

  16. Inverse Doppler Effects in Broadband Acoustic Metamaterials.

    Zhai, S L; Zhao, X P; Liu, S; Shen, F L; Li, L L; Luo, C R


    The Doppler effect refers to the change in frequency of a wave source as a consequence of the relative motion between the source and an observer. Veselago theoretically predicted that materials with negative refractions can induce inverse Doppler effects. With the development of metamaterials, inverse Doppler effects have been extensively investigated. However, the ideal material parameters prescribed by these metamaterial design approaches are complex and also challenging to obtain experimentally. Here, we demonstrated a method of designing and experimentally characterising arbitrary broadband acoustic metamaterials. These omni-directional, double-negative, acoustic metamaterials are constructed with 'flute-like' acoustic meta-cluster sets with seven double meta-molecules; these metamaterials also overcome the limitations of broadband negative bulk modulus and mass density to provide a region of negative refraction and inverse Doppler effects. It was also shown that inverse Doppler effects can be detected in a flute, which has been popular for thousands of years in Asia and Europe.

  17. Inverse Doppler Effects in Broadband Acoustic Metamaterials

    Zhai, S. L.; Zhao, X. P.; Liu, S.; Shen, F. L.; Li, L. L.; Luo, C. R.


    The Doppler effect refers to the change in frequency of a wave source as a consequence of the relative motion between the source and an observer. Veselago theoretically predicted that materials with negative refractions can induce inverse Doppler effects. With the development of metamaterials, inverse Doppler effects have been extensively investigated. However, the ideal material parameters prescribed by these metamaterial design approaches are complex and also challenging to obtain experimentally. Here, we demonstrated a method of designing and experimentally characterising arbitrary broadband acoustic metamaterials. These omni-directional, double-negative, acoustic metamaterials are constructed with ‘flute-like’ acoustic meta-cluster sets with seven double meta-molecules; these metamaterials also overcome the limitations of broadband negative bulk modulus and mass density to provide a region of negative refraction and inverse Doppler effects. It was also shown that inverse Doppler effects can be detected in a flute, which has been popular for thousands of years in Asia and Europe.

  18. Observation of the Zero Doppler Effect

    Ran, Jia; Zhang, Yewen; Chen, Xiaodong; Fang, Kai; Zhao, Junfei; Chen, Hong


    The normal Doppler effect has well-established applications in many areas of science and technology. Recently, a few experimental demonstrations of the inverse Doppler effect have begun to appear in negative-index metamaterials. Here we report an experimental observation of the zero Doppler effect, that is, no frequency shift irrespective of the relative motion between the wave signal source and the detector in a zero-index metamaterial. This unique phenomenon, accompanied by the normal and inverse Doppler effects, is generated by reflecting a wave from a moving discontinuity in a composite right/left-handed transmission line loaded with varactors when operating in the near zero-index passband, or the right/left-handed passband. This work has revealed a complete picture of the Doppler effect in metamaterials and may lead to potential applications in electromagnetic wave related metrology.

  19. Estimating the Doppler centroid of SAR data

    Madsen, Søren Nørvang


    After reviewing frequency-domain techniques for estimating the Doppler centroid of synthetic-aperture radar (SAR) data, the author describes a time-domain method and highlights its advantages. In particular, a nonlinear time-domain algorithm called the sign-Doppler estimator (SDE) is shown to have...... attractive properties. An evaluation based on an existing SEASAT processor is reported. The time-domain algorithms are shown to be extremely efficient with respect to requirements on calculations and memory, and hence they are well suited to real-time systems where the Doppler estimation is based on raw SAR...... data. For offline processors where the Doppler estimation is performed on processed data, which removes the problem of partial coverage of bright targets, the ΔE estimator and the CDE (correlation Doppler estimator) algorithm give similar performance. However, for nonhomogeneous scenes it is found...

  20. Multifocal pattern VEP perimetry: analysis of sectoral waveforms.

    Klistorner, A I; Graham, S L


    The objective detection of local visual field defects using multi-focal pattern visual evoked potentials (VEP) has recently been described. The individual waveforms show variable polarity in different parts of the visual field due to underlying cortical convolutions. Normal trace arrays were examined to determine if certain areas of similar waveform could be grouped for analysis, while minimising cancellation of data. The VEP was assessed using multi-focal pseudo-randomly alternated pattern stimuli which were cortically scaled in size. Bipolar occipital electrodes were used for recording. Waveforms were compared for different locations within the field up to 25 degrees of eccentricity. Analysis of sectors showing similarly shaped waveforms was performed. Twelve normal subjects were studied. Grouping waveforms by sectors of similar waveform increased the total calculated upper hemifield amplitude by 60%, compared with simple summations of responses for the whole hemifield. The inferior hemifield showed more consistent waveforms throughout, with the amplitude only increasing by 11% with sectoral summation. Intra-subject variability (10.6%) is less for sectors than for individual points (17.3%). Inter-subject amplitude differences are high, calculated at 56% for individual points and 45% for sectors. Due to differences in waveform as a result of underlying cortical anatomy, individual VEP responses from multifocal recordings should be grouped as sectors along the vertical meridian and above and below the horizontal, rather than by hemifields or quadrants. This finding is significant if one is considering within-field grouping strategies similar to the glaucoma hemifield test used in conventional perimetry, or reporting derived overall VEP amplitudes and latencies from a multifocal recording. Large amplitude variations between individuals and small signals from horizontal and upper field seen in single channel recording, still limit the application of this technique as

  1. Binary black hole waveform extraction at null infinity

    Babiuc, M C [Department of Physics, Marshall University, Huntington, WV 25755 (United States); Winicour, J [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Zlochower, Y, E-mail: [Center for Computational Relativity and Gravitation and School of Mathematical Sciences, Rochester Institute of Technology, Rochester, NY 14623 (United States)


    In this paper, we present a work in progress toward an efficient and economical computational module which interfaces between Cauchy and characteristic evolution codes. Our goal is to provide a standardized waveform extraction tool for the numerical relativity community which will allow CCE to be readily applied to a generic Cauchy code. The tool provides a means of unambiguous comparison between the waveforms generated by evolution codes based upon different formulations of the Einstein equations and different numerical approximation.

  2. Seismic Waveform Characterization at LLNL: Analyst Guidelines and Issues

    Ryall, F; Schultz, C A


    In the first section of this paper we present an overview of general set of procedures that we have followed in seismic waveform analysis. In the second section we discuss a number of issues and complexities that we have encountered in analysis of events in the Middle East, North Africa, Europe, and parts of the European Arctic. To illustrate these complexities we can include examples of waveforms recorded over a variety of paths in these regions.

  3. Use and Abuse of the Model Waveform Accuracy Standards

    Lindblom, Lee


    Accuracy standards have been developed to ensure that the waveforms used for gravitational-wave data analysis are good enough to serve their intended purposes. These standards place constraints on certain norms of the frequency-domain representations of the waveform errors. Examples will be presented of possible misinterpretations and misapplications of these standards, whose effect could be to vitiate the quality control they were intended to enforce. Suggestions will be given for ways to avoid these problems. )

  4. Anisotropic wave-equation traveltime and waveform inversion

    Feng, Shihang


    The wave-equation traveltime and waveform inversion (WTW) methodology is developed to invert for anisotropic parameters in a vertical transverse isotropic (VTI) meidum. The simultaneous inversion of anisotropic parameters v0, ε and δ is initially performed using the wave-equation traveltime inversion (WT) method. The WT tomograms are then used as starting background models for VTI full waveform inversion. Preliminary numerical tests on synthetic data demonstrate the feasibility of this method for multi-parameter inversion.

  5. Renal calculus

    Pyrah, Leslie N


    Stone in the urinary tract has fascinated the medical profession from the earliest times and has played an important part in the development of surgery. The earliest major planned operations were for the removal of vesical calculus; renal and ureteric calculi provided the first stimulus for the radiological investigation of the viscera, and the biochemical investigation of the causes of calculus formation has been the training ground for surgeons interested in metabolic disorders. It is therefore no surprise that stone has been the subject of a number of monographs by eminent urologists, but the rapid development of knowledge has made it possible for each one of these authors to produce something new. There is still a technical challenge to the surgeon in the removal of renal calculi, and on this topic we are always glad to have the advice of a master craftsman; but inevitably much of the interest centres on the elucidation of the causes of stone formation and its prevention. Professor Pyrah has had a long an...

  6. Angioplasty and stent treatment of transplant renal artery stenosis.

    Del Pozo, Maitane; Martí, Jordi; Guirado, Lluís; Facundo, Carme; Canal, Cristina; de la Torre, Pablo; Ballarín, José; Díaz, Joan M


    Transplant renal artery stenosis is a major complication that requires a therapeutic approach involving surgery or angioplasty. The aim of this study was to analyse the evolution of renal transplant patients with renal allograft artery stenosis treated by angioplasty and stent placement. Thirteen patients were diagnosed with transplant renal artery stenosis. Clinical suspicion was based on deterioration of renal function and/or poorly controlled hypertension with compatible Doppler ultrasound findings. The diagnosis was confirmed by arteriography, performing an angioplasty with stent placement during the same operation. A progressive improvement in renal function was observed during the first 3 months after the angioplasty, and renal function then remained stable over 2 years. In addition, blood pressure improved during the first 2 years, and as a consequence there was no need to increase the average number of anti-hypertensive drugs administered (2.5 drugs per patient). In conclusion, angioplasty with stent placement is a safe and effective procedure for the treatment of transplant renal artery stenosis.

  7. Renal sinus hyperechogenicity in acute pyelonephritis: description and pathological correlation

    Dacher, J.N.; Monroc, M.; Eurin, D.; Dosseur, P. le [Hopital Charles Nicolle, Rouen (France). Dept. of Pediatric Radiology; Avni, F.; Rypens, F. [Hopital Erasme, Brussels (Belgium). Dept. of Radiology; Francois, A. [Hopital Charles Nicolle, Rouen (France). Dept. of Pathology


    This paper reports on the association between renal sinus hyperechogenicity and acute pyelonephritis. The medical records and imaging studies of 18 children displaying this pattern were retrospectively studied. Thickening of the renal pelvis and renal enlargement were the most frequent associated sonographic abnormalities. Further subtle findings can be found on sonography and colour/power Doppler. Their identification can help in the diagnostic approach to acute pyelonephritis and may obviate the need for other imaging modalities such as enhanced CT or {sup 99} {sup m}Tc-DMSA scintigraphy. Renal sinus hyperechogenicity was also identified in a parallel study performed in female rabbits with experimental pyelonephritis and was shown, histologically, to be related to exudates of fibrin and polymorphonuclear leukocytes, interstitial oedema and micro-abscesses. (orig.) With 3 figs., 18 refs.

  8. Optimal current waveforms for brushless permanent magnet motors

    Moehle, Nicholas; Boyd, Stephen


    In this paper, we give energy-optimal current waveforms for a permanent magnet synchronous motor that result in a desired average torque. Our formulation generalises previous work by including a general back-electromotive force (EMF) wave shape, voltage and current limits, an arbitrary phase winding connection, a simple eddy current loss model, and a trade-off between power loss and torque ripple. Determining the optimal current waveforms requires solving a small convex optimisation problem. We show how to use the alternating direction method of multipliers to find the optimal current in milliseconds or hundreds of microseconds, depending on the processor used, which allows the possibility of generating optimal waveforms in real time. This allows us to adapt in real time to changes in the operating requirements or in the model, such as a change in resistance with winding temperature, or even gross changes like the failure of one winding. Suboptimal waveforms are available in tens or hundreds of microseconds, allowing for quick response after abrupt changes in the desired torque. We demonstrate our approach on a simple numerical example, in which we give the optimal waveforms for a motor with a sinusoidal back-EMF, and for a motor with a more complicated, nonsinusoidal waveform, in both the constant-torque region and constant-power region.

  9. Full Elastic Waveform Search Engine for Near Surface Imaging

    Zhang, J.; Zhang, X.


    For processing land seismic data, the near-surface problem is often very complex and may severely affect our capability to image the subsurface. The current state-of-the-art technology for near surface imaging is the early arrival waveform inversion that solves an acoustic wave-equation problem. However, fitting land seismic data with acoustic wavefield is sometimes invalid. On the other hand, performing elastic waveform inversion is very time-consuming. Similar to a web search engine, we develop a full elastic waveform search engine that includes a large database with synthetic elastic waveforms accounting for a wide range of interval velocity models in the CMP domain. With each CMP gather of real data as an entry, the search engine applies Multiple-Randomized K-Dimensional (MRKD) tree method to find approximate best matches to the entry in about a second. Interpolation of the velocity models at CMP positions creates 2D or 3D Vp, Vs, and density models for the near surface area. The method does not just return one solution; it gives a series of best matches in a solution space. Therefore, the results can help us to examine the resolution and nonuniqueness of the final solution. Further, this full waveform search method can avoid the issues of initial model and cycle skipping that the method of full waveform inversion is difficult to deal with.

  10. Estimation of airway obstruction using oximeter plethysmograph waveform data

    Desmond Renee' A


    Full Text Available Abstract Background Validated measures to assess the severity of airway obstruction in patients with obstructive airway disease are limited. Changes in the pulse oximeter plethysmograph waveform represent fluctuations in arterial flow. Analysis of these fluctuations might be useful clinically if they represent physiologic perturbations resulting from airway obstruction. We tested the hypothesis that the severity of airway obstruction could be estimated using plethysmograph waveform data. Methods Using a closed airway circuit with adjustable inspiratory and expiratory pressure relief valves, airway obstruction was induced in a prospective convenience sample of 31 healthy adult subjects. Maximal change in airway pressure at the mouthpiece was used as a surrogate measure of the degree of obstruction applied. Plethysmograph waveform data and mouthpiece airway pressure were acquired for 60 seconds at increasing levels of inspiratory and expiratory obstruction. At each level of applied obstruction, mean values for maximal change in waveform area under the curve and height as well as maximal change in mouth pressure were calculated for sequential 7.5 second intervals. Correlations of these waveform variables with mouth pressure values were then performed to determine if the magnitude of changes in these variables indicates the severity of airway obstruction. Results There were significant relationships between maximal change in area under the curve (P Conclusion The findings suggest that mathematic interpretation of plethysmograph waveform data may estimate the severity of airway obstruction and be of clinical utility in objective assessment of patients with obstructive airway diseases.

  11. Quantification of wave reflection using peripheral blood pressure waveforms.

    Kim, Chang-Sei; Fazeli, Nima; McMurtry, M Sean; Finegan, Barry A; Hahn, Jin-Oh


    This paper presents a novel minimally invasive method for quantifying blood pressure (BP) wave reflection in the arterial tree. In this method, two peripheral BP waveforms are analyzed to obtain an estimate of central aortic BP waveform, which is used together with a peripheral BP waveform to compute forward and backward pressure waves. These forward and backward waves are then used to quantify the strength of wave reflection in the arterial tree. Two unique strengths of the proposed method are that 1) it replaces highly invasive central aortic BP and flow waveforms required in many existing methods by less invasive peripheral BP waveforms, and 2) it does not require estimation of characteristic impedance. The feasibility of the proposed method was examined in an experimental swine subject under a wide range of physiologic states and in 13 cardiac surgery patients. In the swine subject, the method was comparable to the reference method based on central aortic BP and flow. In cardiac surgery patients, the method was able to estimate forward and backward pressure waves in the absence of any central aortic waveforms: on the average, the root-mean-squared error between actual versus computed forward and backward pressure waves was less than 5 mmHg, and the error between actual versus computed reflection index was less than 0.03.

  12. Biomass Estimation for Individual Trees using Waveform LiDAR

    Wang, K.; Kumar, P.; Dutta, D.


    Vegetation biomass information is important for many ecological models that include terrestrial vegetation in their simulations. Biomass has strong influences on carbon, water, and nutrient cycles. Traditionally biomass estimation requires intensive, and often destructive, field measurements. However, with advances in technology, airborne LiDAR has become a convenient tool for acquiring such information on a large scale. In this study, we use infrared full waveform LiDAR to estimate biomass information for individual trees in the Sangamon River basin in Illinois, USA. During this process, we also develop automated geolocation calibration algorithms for raw waveform LiDAR data. In the summer of 2014, discrete and waveform LiDAR data were collected over the Sangamon River basin. Field measurements commonly used in biomass equations such as diameter at breast height and total tree height were also taken for four sites across the basin. Using discrete LiDAR data, individual trees are delineated. For each tree, a voxelization methods is applied to all waveforms associated with the tree to result in a pseudo-waveform. By relating biomass extrapolated using field measurements from a training set of trees to waveform metrics for each corresponding tree, we are able to estimate biomass on an individual tree basis. The results can be especially useful as current models increase in resolution.

  13. Influential factors for pressure pulse waveform in healthy young adults.

    Du, Yi; Wang, Ling; Li, Shuyu; Zhi, Guang; Li, Deyu; Zhang, Chi


    The effects of gender and other contributory factors on pulse waveform are still under arguments. In view of different results caused by few considerations of possible influential factors and general agreement of gender relating to pulse waveform, this study aims to address the confounding factors interfering with the association between gender and pulse waveform characteristics. A novel method was proposed to noninvasively detect pressure pulse wave and assess the morphology of pulse wave. Forty healthy young subjects were included in the present research. Height, weight, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were measured manually and body mass index (BMI), pulse blood pressure (PP) and heart rate (HR) were calculated automatically. Student's t test was used to analyze the gender difference and analysis of variance (ANOVA) to examine the effects of intrinsic factors. Univariate regression analysis was performed to assess the main factors on the waveform characteristics. Waveform features were found significantly different between genders. However this study indicates that the main factors for time-related and amplitude-related parameters are HR and SBP respectively. In conclusion, the impact of HR and SBP on pulse waveform features should not be underestimated, especially when analyzing the gender difference.

  14. Design and Testing of Space Telemetry SCA Waveform

    Mortensen, Dale J.; Handler, Louis M.; Quinn, Todd M.


    A Software Communications Architecture (SCA) Waveform for space telemetry is being developed at the NASA Glenn Research Center (GRC). The space telemetry waveform is implemented in a laboratory testbed consisting of general purpose processors, field programmable gate arrays (FPGAs), analog-to-digital converters (ADCs), and digital-to-analog converters (DACs). The radio hardware is integrated with an SCA Core Framework and other software development tools. The waveform design is described from both the bottom-up signal processing and top-down software component perspectives. Simulations and model-based design techniques used for signal processing subsystems are presented. Testing with legacy hardware-based modems verifies proper design implementation and dynamic waveform operations. The waveform development is part of an effort by NASA to define an open architecture for space based reconfigurable transceivers. Use of the SCA as a reference has increased understanding of software defined radio architectures. However, since space requirements put a premium on size, mass, and power, the SCA may be impractical for today s space ready technology. Specific requirements for an SCA waveform and other lessons learned from this development are discussed.

  15. Waveform descriptor for pulse onset detection of intracranial pressure signal.

    Yang, Li; Zhao, Mingxi; Peng, Chenglin; Hu, Xiao; Feng, Hua; Ji, Zhong


    We present an algorithm to identify the onset of intracranial pressure (ICP) pulses. The algorithm creates a waveform descriptor to extract the feature of each local minimum of the waveform and then identifies the onset by comparing the feature with a customized template. The waveform descriptor is derived by transforming the vectors connecting a given point and the local waveform samples around it into log-polar coordinates and ranking them into uniform bins. Using an ICP dataset consisting of 40933 normal beats and 306 segments of artifacts and noise, we investigated the performance of our algorithm (waveform descriptor, WD), global minimum within a sliding window (GM) and two other algorithms originally proposed for arterial blood pressure (ABP) signal (slope sum function, SSF and pulse waveform delineator, PUD). As a result, all the four algorithms showed good performance and WD showed overall better one. At a tolerance level of 30 ms (i.e., the predicted onset and ground truth were considered as correctly matched if the distance between the two was equal or less than 30 ms), WD achieved a sensitivity of 0.9723 and PPV of 0.9475, GM achieved a sensitivity of 0.9226 and PPV of 0.8968, PUD achieved a sensitivity of 0.9599 and PPV of 0.9327 and SSF, a sensitivity of 0.9720 and PPV of 0.9136. The evaluation indicates that the algorithms are effective for identifying the onset of ICP pulses.

  16. An improved driving waveform reference grayscale of electrophoretic displays

    Wang, Li; Yi, Zichuan; Peng, Bao; Zhou, Guofu


    Driving waveform is an important component for gray scale display on the electrophoretic display (EPD). In the traditional driving waveform, a white reference gray scale is formed before writing a new image. However, the reflectance value can not reach agreement in each gray scale transformation. In this paper, a new driving waveform, which has a short waiting time after the formation of reference gray scale, is proposed to improve the consistency of reference gray scale. Firstly, the property of the particles in the microcapsule is analyzed and the change of the EPD reflectance after the white reference gray scale formation is studied. Secondly, the reflectance change curve is fitted by using polynomial and the duration of the waiting time is determined. Thirdly, a set of the new driving waveform is designed by using the rule of DC balance and some real E-ink commercial EPDs are used to test the performance. Experimental results show that the effect of the new driving waveform has a better performance than traditional waveforms.

  17. Frequency-domain waveform inversion using the unwrapped phase

    Choi, Yun Seok


    Phase wrapping in the frequency-domain (or cycle skipping in the time-domain) is the major cause of the local minima problem in the waveform inversion. The unwrapped phase has the potential to provide us with a robust and reliable waveform inversion, with reduced local minima. We propose a waveform inversion algorithm using the unwrapped phase objective function in the frequency-domain. The unwrapped phase, or what we call the instantaneous traveltime, is given by the imaginary part of dividing the derivative of the wavefield with respect to the angular frequency by the wavefield itself. As a result, the objective function is given a traveltime-like function, which allows us to smooth it and reduce its nonlinearity. The gradient of the objective function is computed using the back-propagation algorithm based on the adjoint-state technique. We apply both our waveform inversion algorithm using the unwrapped phase and the conventional waveform inversion and show that our inversion algorithm gives better convergence to the true model than the conventional waveform inversion. © 2011 Society of Exploration Geophysicists.

  18. Talker identification from analysis of raw complex waveforms

    Stokes, Michael A.


    Stokes (1996) demonstrated that visual inspection of raw complex waveforms can be used to identify a vowel produced by a talker. This research resulted in the MAS Model of Vowel Perception and Production (Stokes, 1998; More recently, another experiment extended this work to female talkers as well as male talkers (Stokes, 2001). Together, this research represents the only ongoing comprehensive research involving visual inspection of raw complex waveforms for identifying vowels produced by any talker. As an extension of the work, the present study involves identifying a talker from a waveform display. Unique voice signatures identified from waveform displays are used to identify a talker from a set of 10 talkers in the same way as one would identify a person from fingerprints. In two trials (the word who'd in trial 1 and heed in trial 2), a talker was correctly identified from a set of 10 unique talkers per trial using small visual samples of waveforms and matching it to a waveform sample of the talkers to be identified.

  19. Modularized seismic full waveform inversion based on waveform sensitivity kernels - The software package ASKI

    Schumacher, Florian; Friederich, Wolfgang; Lamara, Samir; Gutt, Phillip; Paffrath, Marcel


    We present a seismic full waveform inversion concept for applications ranging from seismological to enineering contexts, based on sensitivity kernels for full waveforms. The kernels are derived from Born scattering theory as the Fréchet derivatives of linearized frequency-domain full waveform data functionals, quantifying the influence of elastic earth model parameters and density on the data values. For a specific source-receiver combination, the kernel is computed from the displacement and strain field spectrum originating from the source evaluated throughout the inversion domain, as well as the Green function spectrum and its strains originating from the receiver. By storing the wavefield spectra of specific sources/receivers, they can be re-used for kernel computation for different specific source-receiver combinations, optimizing the total number of required forward simulations. In the iterative inversion procedure, the solution of the forward problem, the computation of sensitivity kernels and the derivation of a model update is held completely separate. In particular, the model description for the forward problem and the description of the inverted model update are kept independent. Hence, the resolution of the inverted model as well as the complexity of solving the forward problem can be iteratively increased (with increasing frequency content of the inverted data subset). This may regularize the overall inverse problem and optimizes the computational effort of both, solving the forward problem and computing the model update. The required interconnection of arbitrary unstructured volume and point grids is realized by generalized high-order integration rules and 3D-unstructured interpolation methods. The model update is inferred solving a minimization problem in a least-squares sense, resulting in Gauss-Newton convergence of the overall inversion process. The inversion method was implemented in the modularized software package ASKI (Analysis of Sensitivity

  20. Late renal vein thrombosis associated with recurrence of membranous nephropathy in a renal allograft: a case report.

    Carrasco, A; Díaz, C; Flores, J C; Briones, E; Otipka, N


    Allograft renal vein thrombosis (RVT) is an uncommon but potentially catastrophic complication. Although it usually occurs in the early posttransplant period and is associated with surgical complications or vascular rejection, it may develop later, when it is generally related with a hypercoagulable state. Typical clinical presentation is sudden oligoanuric acute renal failure, and hematuria, with a painful and swollen renal allograft. Confirmation of the diagnosis requires Doppler ultrasound and computed tomography. Herein we have reported a successfully treated case of late RVT that developed in an allograft with recurrent membranous nephropathy associated with the nephrotic syndrome. The patient fully recovered renal graft function a few days after presentation, which was related to anticoagulant therapy. We demonstrated complete recanalization of the venous thrombosis.

  1. System and Method for Generating a Frequency Modulated Linear Laser Waveform

    Pierrottet, Diego F. (Inventor); Petway, Larry B. (Inventor); Amzajerdian, Farzin (Inventor); Barnes, Bruce W. (Inventor); Lockard, George E. (Inventor); Hines, Glenn D. (Inventor)


    A system for generating a frequency modulated linear laser waveform includes a single frequency laser generator to produce a laser output signal. An electro-optical modulator modulates the frequency of the laser output signal to define a linear triangular waveform. An optical circulator passes the linear triangular waveform to a band-pass optical filter to filter out harmonic frequencies created in the waveform during modulation of the laser output signal, to define a pure filtered modulated waveform having a very narrow bandwidth. The optical circulator receives the pure filtered modulated laser waveform and transmits the modulated laser waveform to a target.

  2. System and Method for Generating a Frequency Modulated Linear Laser Waveform

    Pierrottet, Diego F. (Inventor); Petway, Larry B. (Inventor); Amzajerdian, Farzin (Inventor); Barnes, Bruce W. (Inventor); Lockard, George E. (Inventor); Hines, Glenn D. (Inventor)


    A system for generating a frequency modulated linear laser waveform includes a single frequency laser generator to produce a laser output signal. An electro-optical modulator modulates the frequency of the laser output signal to define a linear triangular waveform. An optical circulator passes the linear triangular waveform to a band-pass optical filter to filter out harmonic frequencies created in the waveform during modulation of the laser output signal, to define a pure filtered modulated waveform having a very narrow bandwidth. The optical circulator receives the pure filtered modulated laser waveform and transmits the modulated laser waveform to a target.

  3. Absence of Doppler signal in transcranial color-coded ultrasonography may be confirmatory for brain death: A case report

    Mehmet Akif Topçuoğlu


    Full Text Available Transcranial Doppler ultrasonography (TCD is a valuable tool for demonstrating cerebral circulatory arrest (CCA in the setting of brain death. Complete reversal of diastolic flow (to-and-fro flow and systolic spikes in bilateral terminal internal carotid arteries and vertebrobasilar circulation are considered as specific sonogram configurations supporting the diagnosis of CCA. Because of the possibility of sonic bone window impermeability, absence of any waveform in TCD is not confirmatory for CCA unless there is documentation of disappearance of a previously well detected signal by the same recording settings. Transcranial color-coded sonography (TCCS with B-mode imaging can reliably detect adequacy of bone windows with clarity contralateral skull and ipsilateral planum temporale visualization. Therefore, absence of detectable intracranial Doppler signal along with available ultrasound window in TCCS can confirm clinical diagnosis of brain death. We herein discuss this entity from the frame of a representative case.

  4. Renal actinomycosis with concomitant renal vein thrombosis.

    Chang, Dong-Suk; Jang, Won Ik; Jung, Ji Yoon; Chung, Sarah; Choi, Dae Eun; Na, Ki-Ryang; Lee, Kang Wook; Shin, Yong-Tai


    Renal actinomycosis is a rare infection caused by fungi of the genus Actinomyces. A 74-year-old male was admitted to our hospital because of gross hematuria with urinary symptoms and intermittent chills. Computed tomography of the abdomen showed thrombosis in the left renal vein and diffuse, heterogeneous enlargement of the left kidney. After nephrectomy, sulfur granules with chronic suppurative inflammation were seen microscopically, and the histopathological diagnosis was renal actinomycosis. Our case is the first report of renal actinomycosis with renal vein thrombosis.

  5. Global and local waveform simulations using the VERCE platform

    Garth, Thomas; Saleh, Rafiq; Spinuso, Alessandro; Gemund, Andre; Casarotti, Emanuele; Magnoni, Federica; Krischner, Lion; Igel, Heiner; Schlichtweg, Horst; Frank, Anton; Michelini, Alberto; Vilotte, Jean-Pierre; Rietbrock, Andreas


    In recent years the potential to increase resolution of seismic imaging by full waveform inversion has been demonstrated on a range of scales from basin to continental scales. These techniques rely on harnessing the computational power of large supercomputers, and running large parallel codes to simulate the seismic wave field in a three-dimensional geological setting. The VERCE platform is designed to make these full waveform techniques accessible to a far wider spectrum of the seismological community. The platform supports the two widely used spectral element simulation programs SPECFEM3D Cartesian, and SPECFEM3D globe, allowing users to run a wide range of simulations. In the SPECFEM3D Cartesian implementation the user can run waveform simulations on a range of pre-loaded meshes and velocity models for specific areas, or upload their own velocity model and mesh. In the new SPECFEM3D globe implementation, the user will be able to select from a number of continent scale model regions, or perform waveform simulations for the whole earth. Earthquake focal mechanisms can be downloaded within the platform, for example from the GCMT catalogue, or users can upload their own focal mechanism catalogue through the platform. The simulations can be run on a range of European supercomputers in the PRACE network. Once a job has been submitted and run through the platform, the simulated waveforms can be manipulated or downloaded for further analysis. The misfit between the simulated and recorded waveforms can then be calculated through the platform through three interoperable workflows, for raw-data access (FDSN) and caching, pre-processing and finally misfit. The last workflow makes use of the Pyflex analysis software. In addition, the VERCE platform can be used to produce animations of waveform propagation through the velocity model, and synthetic shakemaps. All these data-products are made discoverable and re-usable thanks to the VERCE data and metadata management layer. We

  6. A Simple Adaptive Transfer Function for Deriving the Central Blood Pressure Waveform from a Radial Blood Pressure Waveform.

    Gao, Mingwu; Rose, William C; Fetics, Barry; Kass, David A; Chen, Chen-Huan; Mukkamala, Ramakrishna


    Generalized transfer functions (GTFs) are available to compute the more relevant central blood pressure (BP) waveform from a more easily measured radial BP waveform. However, GTFs are population averages and therefore may not adapt to variations in pulse pressure (PP) amplification (ratio of radial to central PP). A simple adaptive transfer function (ATF) was developed. First, the transfer function is defined in terms of the wave travel time and reflection coefficient parameters of an arterial model. Then, the parameters are estimated from the radial BP waveform by exploiting the observation that central BP waveforms exhibit exponential diastolic decays. The ATF was assessed using the original data that helped popularize the GTF. These data included radial BP waveforms and invasive reference central BP waveforms from cardiac catheterization patients. The data were divided into low, middle, and high PP amplification groups. The ATF estimated central BP with greater accuracy than GTFs in the low PP amplification group (e.g., central systolic BP and PP root-mean-square-errors of 3.3 and 4.2 mm Hg versus 6.2 and 7.1 mm Hg; p ≤ 0.05) while showing similar accuracy in the higher PP amplification groups. The ATF may permit more accurate, non-invasive central BP monitoring in elderly and hypertensive patients.


    Soraia Geraldo Rozza Lopes


    Full Text Available El objetivo del estudio fue comprender el significado de espera del trasplante renal para las mujeres en hemodiálisis. Se trata de un estudio cualitativo-interpretativo, realizado con 12 mujeres en hemodiálisis en Florianópolis. Los datos fueron recolectados a través de entrevistas en profundidad en el domicilio. Fue utilizado el software Etnografh 6.0 para la pre-codificación y posterior al análisis interpretativo emergieron dos categorías: “las sombras del momento actual”, que mostró que las dificultades iniciales de la enfermedad están presentes, pero las mujeres pueden hacer frente mejor a la enfermedad y el tratamiento. La segunda categoría, “la luz del trasplante renal”, muestra la esperanza impulsada por la entrada en la lista de espera para un trasplante.

  8. Renal failure


    930564 Dwell times affect the local host de-fence mechanism of peritoneal dialysis patients.WANG Tao(汪涛),et al.Renal Instit,SunYatsen Med Univ,Guangzhou,510080.Chin JNephrol 1993;9(2):75—77.The effect of different intraperitoneal awelltimes on the local host defence in 6 peritonealdialysis patients was studied.A significant de-crease in the number of peritoneal cells,IgG con-centration and the phagoeytosis and bactericidalactivity of macrophages was determined when thedwell time decreased from 12 to 4 hs or form 4 to0.5hs,but the peroxidase activity in macrophagesincreased significantly.All variables,except theperoxidase activity in macrophages,showed nosignificant difference between patients of high or

  9. Traumatismo renal

    Rocha, Sofia Rosa Moura Gomes da


    Introdução: A realização deste trabalho visa a elaboração de uma revisão sistematizada subordinada à temática da traumatologia renal. Objectivos: Os principais objectivos deste trabalho são: apurar a etiologia, definir a classificação, analisar o diagnóstico e expôr o tratamento e as complicações. Desenvolvimento: Os traumatismos são a principal causa de morte antes dos 40 anos. O rim é o órgão do aparelho génito-urinário mais frequentemente atingido. Os traumatismos renais são mais fre...

  10. Wideband radar micro-doppler applications

    Tahmoush, Dave


    Wideband radar provides a significant improvement over traditional narrowband radars for micro-Doppler analysis because the high bandwidth can be used to separate many of the signals in range, allowing a simpler decomposition of the micro-Doppler signals. Recent wideband radar work has focused on micro-Doppler, but there is a point where the narrowband approach used to analyze the micro-Doppler signals breaks down. The effect is shown to be independent of frequency, but the error relative to the bandwidth is shown to be inversely proportional to the frequency and proportional to the velocity of the subject. This error can create a smearing effect in the observed Doppler if it is not corrected, leading to reduced signal-to-noise and the appearance of more diffuse targets in Doppler space. In range-space, wideband data can also break the subject into several range bins, affecting the observed signal to noise ratio. The possible applications of wideband micro-Doppler radar are also shown, including the separation of arm movement from human motion which implies that the arms are not encumbered.

  11. Rotational Doppler effect in nonlinear optics

    Li, Guixin; Zentgraf, Thomas; Zhang, Shuang


    The translational Doppler effect of electromagnetic and sound waves has been successfully applied in measurements of the speed and direction of vehicles, astronomical objects and blood flow in human bodies, and for the Global Positioning System. The Doppler effect plays a key role for some important quantum phenomena such as the broadened emission spectra of atoms and has benefited cooling and trapping of atoms with laser light. Despite numerous successful applications of the translational Doppler effect, it fails to measure the rotation frequency of a spinning object when the probing wave propagates along its rotation axis. This constraint was circumvented by deploying the angular momentum of electromagnetic waves--the so-called rotational Doppler effect. Here, we report on the demonstration of rotational Doppler shift in nonlinear optics. The Doppler frequency shift is determined for the second harmonic generation of a circularly polarized beam passing through a spinning nonlinear optical crystal with three-fold rotational symmetry. We find that the second harmonic generation signal with circular polarization opposite to that of the fundamental beam experiences a Doppler shift of three times the rotation frequency of the optical crystal. This demonstration is of fundamental significance in nonlinear optics, as it provides us with insight into the interaction of light with moving media in the nonlinear optical regime.

  12. Staggered Multiple-PRF Ultrafast Color Doppler.

    Posada, Daniel; Poree, Jonathan; Pellissier, Arnaud; Chayer, Boris; Tournoux, Francois; Cloutier, Guy; Garcia, Damien


    Color Doppler imaging is an established pulsed ultrasound technique to visualize blood flow non-invasively. High-frame-rate (ultrafast) color Doppler, by emissions of plane or circular wavefronts, allows severalfold increase in frame rates. Conventional and ultrafast color Doppler are both limited by the range-velocity dilemma, which may result in velocity folding (aliasing) for large depths and/or large velocities. We investigated multiple pulse-repetition-frequency (PRF) emissions arranged in a series of staggered intervals to remove aliasing in ultrafast color Doppler. Staggered PRF is an emission process where time delays between successive pulse transmissions change in an alternating way. We tested staggered dual- and triple-PRF ultrafast color Doppler, 1) in vitro in a spinning disc and a free jet flow, and 2) in vivo in a human left ventricle. The in vitro results showed that the Nyquist velocity could be extended to up to 6 times the conventional limit. We found coefficients of determination r(2) ≥ 0.98 between the de-aliased and ground-truth velocities. Consistent de-aliased Doppler images were also obtained in the human left heart. Our results demonstrate that staggered multiple-PRF ultrafast color Doppler is efficient for high-velocity high-frame-rate blood flow imaging. This is particularly relevant for new developments in ultrasound imaging relying on accurate velocity measurements.

  13. Regional renal venous hypertension and left-sided varicocele

    O. B. Zhukov; A. V. Verzin; P. L. Penkov


    One of the most frequent correctable causes of male infertility is a varicocele. The etiology and pathogenesis of varicocele to date is a matter of debate. The aim of our study was to determine the causes and incidence of regional renal hypertension in patients with leftsided varicocele. The study involved 110 patients with left-sided varicocele in age from 18 to 35 years. Algorithm for evaluation of patients with left-sided varicocele included: physical examination, ultrasound with Doppler k...

  14. Renal transplant improves pulmonary hypertension in patients with end stage renal disease

    Bozbas Serife


    Full Text Available Abstract Background Pulmonary hypertension (PH is present in a significant proportion of patients with end stage renal disease (ESRD and is of prognostic importance. Data on the effect of renal transplant on PH is very limited. In this study, the aim was to examine the effect of renal transplant on systolic pulmonary artery pressure (SPAP determined by Doppler echocardiography. Methods Analysis was performed on the records of 500 consecutive patients who underwent renal transplant at our center between the years 1999 to 2008. The prevalence of PH in the preoperative assessment period was established. Patients were diagnosed as having PH when measured SPAP values were > 35 mm Hg. Results Pulmonary hypertension was detected in 85 of the 500 (17% patients under pre-transplant evaluation. At post-transplant follow up Doppler echocardiographic examination was performed on 50 of the 85 patients. After exclusion of 8 cases (1 due to massive pulmonary thromboemboli; 7 due to graft failure requiring dialysis therapy analyses were performed on 42 patients who had undergone both pre- and post-transplant echocardiographic examination. Mean SPAP at pre-transplant evaluation was 45.9 ± 8.8 mm Hg and in 6 (14.3% cases SPAP was above 50 mm Hg. Compared to pre-transplant values, a significant decrease was observed in mean SPAP values in an average of 53 months of postoperative follow up (41.8 ± 7.4 mm Hg vs. 45.9 ± 8.8 mm Hg, p Conclusion These findings indicate that patients with ESRD accompanied by PH may benefit from renal transplant. Further research is required for more concrete conclusions to be drawn on this subject.

  15. Two-dimensional and three-dimensional Doppler assessment of fetal growth restriction with different severity and onset.

    Luria, Oded; Barnea, Ofer; Shalev, Josef; Barkat, Jonathan; Kovo, Michal; Golan, Abraham; Bar, Jacob


    To investigate the role of three-dimensional (3D) power Doppler ultrasonography in the assessment of fetal growth-restriction (FGR) with various degrees of severity and onset, and compare the results with the analysis of two-dimensional (2D) Doppler. Vascular indices extracted from 3D Doppler measurements of the placenta were compared with indices of flow-velocity waveforms extracted from 2D Doppler measurements of the major sites of the fetal circulation between FGR (study group) and uncomplicated pregnancies (control group) from 25 to 38 weeks' gestation. Three-dimensional indices were significantly lower in pregnancies complicated by FGR compared with uncomplicated pregnancies. When measured in placental periphery, vascularization index was 9.4 ± 9.6 in FGR pregnancies compared with 16 ± 14.7, P = 0.04. Flow index was 33.9 ± 6.9 compared with 38.7 ± 4.9, P = 0.03 and the vascularization-flow index was 3.8 ± 4.3 compared with 6.5 ± 6, respectively, P = 0.03. Among the conventional 2D indices, umbilical artery and middle cerebral artery pulsatility indices were not significantly different between the FGR and control groups. Higher rate of maternal or fetal compartment vascular lesions were detected in the FGR group. Three-dimensional Doppler was found to be more strongly associated with placental vascular compromise than conventional 2D Doppler, regardless of severity and onset of fetal growth restriction. © 2012 John Wiley & Sons, Ltd.

  16. Estimation of earthquake source parameters by the inversion of waveform data: synthetic waveforms

    Sipkin, S.A.


    Two methods are presented for the recovery of a time-dependent moment-tensor source from waveform data. One procedure utilizes multichannel signal-enhancement theory; in the other a multichannel vector-deconvolution approach, developed by Oldenburg (1982) and based on Backus-Gilbert inverse theory, is used. These methods have the advantage of being extremely flexible; both may be used either routinely or as research tools for studying particular earthquakes in detail. Both methods are also robust with respect to small errors in the Green's functions and may be used to refine estimates of source depth by minimizing the misfits to the data. The multichannel vector-deconvolution approach, although it requires more interaction, also allows a trade-off between resolution and accuracy, and complete statistics for the solution are obtained. The procedures have been tested using a number of synthetic body-wave data sets, including point and complex sources, with satisfactory results. ?? 1982.

  17. Doppler backscatter properties of a blood-mimicking fluid for Doppler performance assessment.

    Ramnarine, K V; Hoskins, P R; Routh, H F; Davidson, F


    The Doppler backscatter properties of a blood-mimickig fluid (BMF) were studied to evaluate its suitability for use in a Doppler flow test object. Measurements were performed using a flow rig with C-flex tubing and BMF flow produced by a roller pump or a gear pump. A SciMed Doppler system was used to measure the backscattered Doppler power with a root-mean-square power meter connected to the audio output. Studies investigated the dependence of the backscattered Doppler power of the BMF with: circulation time; batch and operator preparations; storage; sieve size; flow speed; and pump type. A comparison was made with human red blood cells resuspended in saline. The backscatter properties are stable and within International Electrotechnical Commission requirements. The BMF is suitable for use in a test object for Doppler performance assessment.

  18. Pseudoaneurysm of the renal artery following partial nephrectomy: Imaging findings and coil embolization

    Cohenpour, M. [Department of Diagnostic Imaging, Assaf Harofeh Medical Center, Zerifin (Israel)], E-mail:; Strauss, S.; Gottlieb, P.; Peer, A. [Department of Diagnostic Imaging, Assaf Harofeh Medical Center, Zerifin (Israel); Rimon, U. [Department of diagnostic imaging, Sheba Medical Center, Tel Hashomer (Israel); Stav, K. [Department of Urology, Assaf Harofeh Medical Center, Zerifin (Israel); Gayer, G. [Department of Diagnostic Imaging, Assaf Harofeh Medical Center, Zerifin (Israel)


    Aim: To present the imaging findings of five patients with renal artery pseudoaneurysm (RAP) after partial nephrectomy. Methods: Five patients (four men and one woman) with RAP as a complication of partial nephrectomy were studied. The diagnosis of RAP was established using contrast-enhanced computed tomography (CT) in three patients and renal angiography in two patients. In two cases, the diagnosis was evident on ultrasound with colour Doppler. Results: The indication for partial nephrectomy (open approach in four patients and laparoscopic in one patient) was a space-occupying lesion, which proved to be a renal cell carcinoma. All patients presented with macroscopic haematuria, 1-21 days (mean 12.2 days) after surgery. In three of patients the definitive diagnostic imaging method was contrast-enhanced CT. The arterial phase of CT showed a well-circumscribed dense collection of contrast material located within the renal parenchyma. In two other patients the initial and conclusive diagnostic imaging method was renal angiography. All patients underwent selective renal angiography with therapeutic coil embolization. The procedure failed in one patient, which necessitated nephrectomy. Conclusions: Pseudoaneurysm of the renal artery should be considered in patients presenting with macrohaematuria after nephron-sparing surgery. The diagnosis can be established using contrast-enhanced CT, ultrasound with colour Doppler, or angiography. Renal angiography with selective embolization is a safe and efficacious technique for managing the condition.

  19. Transcranial Doppler investigation of hemodynamic alterations associated with blunt cervical vascular injuries in trauma patients.

    Purvis, Dianna L; Crutchfield, Kevin; Trickey, Amber W; Aldaghlas, Tayseer; Rizzo, Anne; Sikdar, Siddhartha


    Blunt cervical vascular injuries, often missed with current screening methods, have substantial morbidity and mortality, and there is a need for improved screening. Elucidation of cerebral hemodynamic alterations may facilitate serial bedside monitoring and improved management. Thus, the objective of this study was to define cerebral flow alterations associated with single blunt cervical vascular injuries using transcranial Doppler sonography and subsequent Doppler waveform analyses in a trauma population. In this prospective pilot study, patients with suspected blunt cervical vascular injuries had diagnoses by computed tomographic angiography and were examined using transcranial Doppler sonography to define cerebral hemodynamics. Multiple vessel injuries were excluded for this analysis, as the focus was to identify hemodynamic alterations from isolated injuries. The inverse damping factor characterized altered extracranial flow patterns; middle cerebral artery flow velocities, the pulsatility index, and their asymmetries characterized altered intracranial flow patterns. Twenty-three trauma patients were evaluated: 4 with single internal carotid artery injuries, 5 with single vertebral artery injuries, and 14 without blunt cervical vascular injuries. All internal carotid artery injuries showed a reduced inverse damping factor in the internal carotid artery and dampened ipsilateral mean flow and peak systolic velocities in the middle cerebral artery. Vertebral artery injuries produced asymmetry of a similar magnitude in the middle cerebral artery mean flow velocity with end-diastolic velocity alterations. These data indicate that extracranial and intracranial hemodynamic alterations occur with internal carotid artery and vertebral artery blunt cervical vascular injuries and can be quantified in the acute injury phase by transcranial Doppler indices. Further study is required to elucidate cerebral flow changes resulting from a single blunt cervical vascular injury

  20. Quantitative analysis of sensor for pressure waveform measurement

    Tyan Chu-Chang


    Full Text Available Abstract Background Arterial pressure waveforms contain important diagnostic and physiological information since their contour depends on a healthy cardiovascular system 1. A sensor was placed at the measured artery and some contact pressure was used to measure the pressure waveform. However, where is the location of the sensor just about enough to detect a complete pressure waveform for the diagnosis? How much contact pressure is needed over the pulse point? These two problems still remain unresolved. Method In this study, we propose a quantitative analysis to evaluate the pressure waveform for locating the position and applying the appropriate force between the sensor and the radial artery. The two-axis mechanism and the modified sensor have been designed to estimate the radial arterial width and detect the contact pressure. The template matching method was used to analyze the pressure waveform. In the X-axis scan, we found that the arterial diameter changed waveform (ADCW and the pressure waveform would change from small to large and then back to small again when the sensor was moved across the radial artery. In the Z-axis scan, we also found that the ADCW and the pressure waveform would change from small to large and then back to small again when the applied contact pressure continuously increased. Results In the X-axis scan, the template correlation coefficients of the left and right boundaries of the radial arterial width were 0.987 ± 0.016 and 0.978 ± 0.028, respectively. In the Z-axis scan, when the excessive contact pressure was more than 100 mm Hg, the template correlation was below 0.983. In applying force, when using the maximum amplitude as the criteria level, the lower contact pressure (r = 0.988 ± 0.004 was better than the higher contact pressure (r = 0.976 ± 0.012. Conclusions Although, the optimal detective position has to be close to the middle of the radial arterial, the pressure waveform also has a good completeness with

  1. A Time Domain Waveform for Testing General Relativity

    Huwyler, Cédric; Jetzer, Philippe


    Gravitational-wave parameter estimation is only as good as the theory the waveform generation models are based upon. It is therefore crucial to test General Relativity (GR) once data becomes available. Many previous works, such as studies connected with the ppE framework by Yunes and Pretorius, rely on the stationary phase approximation (SPA) to model deviations from GR in the frequency domain. As Fast Fourier Transform algorithms have become considerably faster and in order to circumvent possible problems with the SPA, we test GR with corrected time domain waveforms instead of SPA waveforms. Since a considerable amount of work has been done already in the field using SPA waveforms, we establish a connection between leading-order-corrected waveforms in time and frequency domain, concentrating on phase-only corrected terms. In a Markov Chain Monte Carlo study, whose results are preliminary and will only be available later, we will assess the ability of the eLISA detector to measure deviations from GR for signa...

  2. Ocular pressure waveform reflects ventricular bigeminy and aortic insufficiency

    Jean B Kassem


    Full Text Available Ocular pulse amplitude (OPA is defined as the difference between maximum and minimum intraocular pressure (IOP during a cardiac cycle. Average values of OPA range from 1 to 4 mmHg. The purpose of this investigation is to determine the source of an irregular IOP waveform with elevated OPA in a 48-year-old male. Ocular pressure waveforms had an unusual shape consistent with early ventricular contraction. With a normal IOP, OPA was 9 mmHg, which is extraordinarily high. The subject was examined by a cardiologist and was determined to be in ventricular bigeminy. In addition, he had bounding carotid pulses and echocardiogram confirmed aortic insufficiency. After replacement of the aortic valve, the bigeminy resolved and the ocular pulse waveform became regular in appearance with an OPA of 1.6-2.0 mmHg. The ocular pressure waveform is a direct reflection of hemodynamics. Evaluating this waveform may provide an additional opportunity for screening subjects for cardiovascular anomalies and arrhythmias.

  3. Breast ultrasound computed tomography using waveform inversion with source encoding

    Wang, Kun; Matthews, Thomas; Anis, Fatima; Li, Cuiping; Duric, Neb; Anastasio, Mark A.


    Ultrasound computed tomography (USCT) holds great promise for improving the detection and management of breast cancer. Because they are based on the acoustic wave equation, waveform inversion-based reconstruction methods can produce images that possess improved spatial resolution properties over those produced by ray-based methods. However, waveform inversion methods are computationally demanding and have not been applied widely in USCT breast imaging. In this work, source encoding concepts are employed to develop an accelerated USCT reconstruction method that circumvents the large computational burden of conventional waveform inversion methods. This method, referred to as the waveform inversion with source encoding (WISE) method, encodes the measurement data using a random encoding vector and determines an estimate of the speed-of-sound distribution by solving a stochastic optimization problem by use of a stochastic gradient descent algorithm. Computer-simulation studies are conducted to demonstrate the use of the WISE method. Using a single graphics processing unit card, each iteration can be completed within 25 seconds for a 128 × 128 mm2 reconstruction region. The results suggest that the WISE method maintains the high spatial resolution of waveform inversion methods while significantly reducing the computational burden.

  4. Doppler echocardiography in normal functioning valve prostheses.

    Cha, R; Yang, S S; Salvucci, T; DiBlasi, S


    Even though there has been some criticism regarding the Doppler evaluation in prosthetic valves because of inter-observer and intra-observer variability, among other factors, and Doppler study has a tendency to have falsely high gradients compared to invasive studies, especially mechanical aortic prostheses, Doppler evaluation can provide reliable hemodynamic information about valve function. This test may be particularly useful if used serially, when baseline values are known. Doppler measurement of gradient and valve area has an expected normal range that is specific for the prosthetic type, size, anatomical position, and chronological age. Clearly, a database involving these aspects is needed to provide a more accurate normal range. This study is intended to provide guidance for echocardiographers.

  5. Teaching the Doppler effect in astrophysics

    Hughes, Stephen W.; Cowley, Michael


    The Doppler effect is a shift in the frequency of waves emitted from an object moving relative to the observer. By observing and analysing the Doppler shift in electromagnetic waves from astronomical objects, astronomers gain greater insight into the structure and operation of our Universe. In this paper, a simple technique is described for teaching the basics of the Doppler effect to undergraduate astrophysics students using acoustic waves. An advantage of the technique is that it produces a visual representation of the acoustic Doppler shift. The equipment comprises a 40 kHz acoustic transmitter and a microphone. The sound is bounced off a computer fan and the signal collected by a DrDAQ ADC and processed by a spectrum analyser. Widening of the spectrum is observed as the fan power supply potential is increased from 4 to 12 V.

  6. High range resolution micro-Doppler analysis

    Cammenga, Zachary A.; Smith, Graeme E.; Baker, Christopher J.


    This paper addresses use of the micro-Doppler effect and the use of high range-resolution profiles to observe complex targets in complex target scenes. The combination of micro-Doppler and high range-resolution provides the ability to separate the motion of complex targets from one another. This ability leads to the differentiation of targets based on their micro-Doppler signatures. Without the high-range resolution, this would not be possible because the individual signatures would not be separable. This paper also addresses the use of the micro-Doppler information and high range-resolution profiles to generate an approximation of the scattering properties of a complex target. This approximation gives insight into the structure of the complex target and, critically, is created without using a pre-determined target model.

  7. High Throughput Direct Detection Doppler Lidar Project

    National Aeronautics and Space Administration — Lite Cycles, Inc. (LCI) proposes to develop a direct-detection Doppler lidar (D3L) technology called ELITE that improves the system optical throughput by more than...

  8. Student Microwave Experiments Involving the Doppler Effect.

    Weber, F. Neff; And Others


    Described is the use of the Doppler Effect with microwaves in the measurement of the acceleration due to gravity of falling objects. The experiments described add to the repertoire of quantitative student microwave experiments. (Author/DS)

  9. Inverse Doppler Effects in Broadband Acoustic Metamaterials

    Zhai, S L; Zhao, X P; Liu, S; Shen, F L; Li, L L; Luo, C R


    .... With the development of metamaterials, inverse Doppler effects have been extensively investigated. However, the ideal material parameters prescribed by these metamaterial design approaches are complex and also challenging to obtain experimentally...

  10. Effects of antenatal dexamethasone administration on fetal and uteroplacental Doppler waveforms in women at risk for spontaneous preterm birth

    Elwani Elsnosy


    Conclusion: Maternal dexamethasone administration to pregnant women at risk of preterm labor improves the blood flow of the maternal uterine artery, fetal MCA, descending aorta and umbilical artery 24 h after its administration.

  11. Optical Doppler shift with structured light


    When a light beam with a transverse spatially varying phase is considered for optical remote sensing, in addition to the usual longitudinal Doppler frequency shift of the returned signal induced by the motion of the scatter along the beam axis, a new transversal Doppler shift appears associated to the motion of the scatterer in the plane perpendicular to the beam axis. We discuss here how this new effect can be used to enhance the current capabilities of optical measurement system...

  12. with Ultrasound Color Doppler Imaging

    Shin Takayama


    Full Text Available Color Doppler imaging (CDI can be used to noninvasively create images of human blood vessels and quantitatively evaluate blood flow in real-time. The purpose of this study was to assess the effects of acupuncture on the blood flow of the peripheral, mesenteric, and retrobulbar arteries by CDI. Statistical significance was defined as P values less than 0.05. Blood flow in the radial and brachial arteries was significantly lower during needle stimulation on LR3 than before in healthy volunteers, but was significantly higher after needle stimulation than before. LR3 stimulation also resulted in a significant decrease in the vascular resistance of the short posterior ciliary artery and no significant change of blood flow through the superior mesenteric artery (SMA during acupuncture. In contrast, ST36 stimulation resulted in a significant increase in blood flow through the SMA and no significant change in the vascular resistance of the retrobulbar arteries. Additionally, acupuncture at previously determined acupoints in patients with open-angle glaucoma led to a significant reduction in the vascular resistance of the central retinal artery and short posterior ciliary artery. Our results suggest that acupuncture can affect blood flow of the peripheral, mesenteric, and retrobulbar arteries, and CDI can be useful to evaluate hemodynamic changes by acupuncture.

  13. Doppler micro sense and avoid radar

    Gorwara, Ashok; Molchanov, Pavlo; Asmolova, Olga


    There is a need for small Sense and Avoid (SAA) systems for small and micro Unmanned Aerial Systems (UAS) to avoid collisions with obstacles and other aircraft. The proposed SAA systems will give drones the ability to "see" close up and give them the agility to maneuver through tight areas. Doppler radar is proposed for use in this sense and avoid system because in contrast to optical or infrared (IR) systems Doppler can work in more harsh conditions such as at dusk, and in rain and snow. And in contrast to ultrasound based systems, Doppler can better sense small sized obstacles such as wires and it can provide a sensing range from a few inches to several miles. An SAA systems comprised of Doppler radar modules and an array of directional antennas that are distributed around the perimeter of the drone can cover the entire sky. These modules are designed so that they can provide the direction to the obstacle and simultaneously generate an alarm signal if the obstacle enters within the SAA system's adjustable "Protection Border". The alarm signal alerts the drone's autopilot to automatically initiate an avoidance maneuver. A series of Doppler radar modules with different ranges, angles of view and transmitting power have been designed for drones of different sizes and applications. The proposed Doppler radar micro SAA system has simple circuitry, works from a 5 volt source and has low power consumption. It is light weight, inexpensive and it can be used for a variety of small unmanned aircraft.

  14. The Doppler effect in NMR spectroscopy.

    Guéron, Maurice


    An NMR sample may be subject to motions, such as those due to sample spinning or to liquid flow. Is the spectrum of such a sample affected by the Doppler effect? The question arises because, instrumental dimensions being much shorter than the wavelength, it is the near-field of the precessing magnetic moment which couples to the receiver coil, rather than the radiated far-field. We expand the near-field into plane propagating waves. For each such wave there is another one with the same amplitude, propagating in the opposite direction. The Doppler shifts are therefore equal and opposite. In the model case of a small fluid sample moving with constant velocity, this leads to a distribution of Doppler shifts which is symmetrical with respect to the unshifted frequency: there is no net spectral shift. We examine the possibility of observing the Doppler distribution in this case. We also consider the case of thermal motion of a gas. We draw attention to the resolved Doppler splitting of molecular rotational transitions in a supersonic burst as observed in a microwave resonator. We also mention briefly the Doppler effect in molecular beam spectroscopy.

  15. Development of a neural network screening aid for diagnosing lower limb peripheral vascular disease from photoelectric plethysmography pulse waveforms.

    Allen, J; Murray, A


    An artificial neural network (ANN) was trained to classify photoelectric plethysmographic (PPG) pulse waveforms for the diagnosis of lower limb peripheral vascular disease (PVD). PPG pulses from the lower limbs, and pre- and post-exercise Doppler ultrasound ankle to brachial systolic blood pressure ratio measurements were obtained from patients referred to a vascular investigation laboratory. A single PPG pulse from the big toe of each leg was processed and normalized, and used as input data to the ANN. The ANN outputs represented the diagnostic classifications (normal, significant PVD and major PVD) and the ANN was trained with the ankle to brachial pressure indices (ABPI). The ANN structure consisted of an input layer (50 neuron units from the PPG pulse input), a single hidden layer (15 neurons) and an output layer (3 neurons for the PVD diagnoses). The back-propagation learning algorithm was used to train the ANN for 500 epochs with a PPG training set of pulses from 100 legs. Test data for network assessment comprised pulses from a further 50 legs (20 normal and 30 PVD, of which 15 were categorized as having major disease). A network sensitivity of 93% and specificity of 85% was achieved with respect to the Doppler ABPI standard, giving a diagnostic accuracy of 90%. The results of this study indicate that a neural network can be trained to distinguish between PPG pulses from normal and diseased lower limb arteries. The simplicity of PPG measurement and neural network classification holds promise for the screening of lower limb arterial PVD.

  16. Shaping the spectrum of random-phase radar waveforms

    Doerry, Armin W.; Marquette, Brandeis


    The various technologies presented herein relate to generation of a desired waveform profile in the form of a spectrum of apparently random noise (e.g., white noise or colored noise), but with precise spectral characteristics. Hence, a waveform profile that could be readily determined (e.g., by a spoofing system) is effectively obscured. Obscuration is achieved by dividing the waveform into a series of chips, each with an assigned frequency, wherein the sequence of chips are subsequently randomized. Randomization can be a function of the application of a key to the chip sequence. During processing of the echo pulse, a copy of the randomized transmitted pulse is recovered or regenerated against which the received echo is correlated. Hence, with the echo energy range-compressed in this manner, it is possible to generate a radar image with precise impulse response.

  17. Stimulator with arbitrary waveform for auditory evoked potentials

    Martins, H R; Romao, M; Placido, D; Provenzano, F; Tierra-Criollo, C J [Universidade Federal de Minas Gerais (UFMG), Departamento de Engenharia Eletrica (DEE), Nucleo de Estudos e Pesquisa em Engenharia Biomedica NEPEB, Av. Ant. Carlos, 6627, sala 2206, Pampulha, Belo Horizonte, MG, 31.270-901 (Brazil)


    The technological improvement helps many medical areas. The audiometric exams involving the auditory evoked potentials can make better diagnoses of auditory disorders. This paper proposes the development of a stimulator based on Digital Signal Processor. This stimulator is the first step of an auditory evoked potential system based on the ADSP-BF533 EZ KIT LITE (Analog Devices Company - USA). The stimulator can generate arbitrary waveform like Sine Waves, Modulated Amplitude, Pulses, Bursts and Pips. The waveforms are generated through a graphical interface programmed in C++ in which the user can define the parameters of the waveform. Furthermore, the user can set the exam parameters as number of stimuli, time with stimulation (Time ON) and time without stimulus (Time OFF). In future works will be implemented another parts of the system that includes the acquirement of electroencephalogram and signal processing to estimate and analyze the evoked potential.

  18. Fast evaluation of asymptotic waveforms from gravitational perturbations

    Benedict, Alex G; Lau, Stephen R


    In the context of blackhole perturbation theory, we describe both exact evaluation of an asymptotic waveform from a time series recorded at a finite radial location and its numerical approximation. From the user's standpoint our technique is easy to implement, affords high accuracy, and works for both axial (Regge-Wheeler) and polar (Zerilli) sectors. Our focus is on the ease of implementation with publicly available numerical tables, either as part of an existing evolution code or a post-processing step. Nevertheless, we also present a thorough theoretical discussion of asymptotic waveform evaluation and radiation boundary conditions, which need not be understood by a user of our methods. In particular, we identify (both in the time and frequency domains) analytical asymptotic waveform evaluation kernels, and describe their approximation by techniques developed by Alpert, Greengard, and Hagstrom. This paper also presents new results on the evaluation of far-field signals for the ordinary (acoustic) wave equa...

  19. Schwarz waveform relaxation algorithm for heat equations with distributed delay

    Wu Shu-Lin


    Full Text Available Heat equations with distributed delay are a class of mathematic models that has wide applications in many fields. Numerical computation plays an important role in the investigation of these equations, because the analytic solutions of partial differential equations with time delay are usually unavailable. On the other hand, duo to the delay property, numerical computation of these equations is time-consuming. To reduce the computation time, we analyze in this paper the Schwarz waveform relaxation algorithm with Robin transmission conditions. The Robin transmission conditions contain a free parameter, which has a significant effect on the convergence rate of the Schwarz waveform relaxation algorithm. Determining the Robin parameter is therefore one of the top-priority matters for the study of the Schwarz waveform relaxation algorithm. We provide new formula to fix the Robin parameter and we show numerically that the new Robin parameter is more efficient than the one proposed previously in the literature.

  20. Classification of Pulse Waveforms Using Edit Distance with Real Penalty

    Zhang Dongyu


    Full Text Available Abstract Advances in sensor and signal processing techniques have provided effective tools for quantitative research in traditional Chinese pulse diagnosis (TCPD. Because of the inevitable intraclass variation of pulse patterns, the automatic classification of pulse waveforms has remained a difficult problem. In this paper, by referring to the edit distance with real penalty (ERP and the recent progress in -nearest neighbors (KNN classifiers, we propose two novel ERP-based KNN classifiers. Taking advantage of the metric property of ERP, we first develop an ERP-induced inner product and a Gaussian ERP kernel, then embed them into difference-weighted KNN classifiers, and finally develop two novel classifiers for pulse waveform classification. The experimental results show that the proposed classifiers are effective for accurate classification of pulse waveform.

  1. Model Waveform Accuracy Requirements for the $\\chi^2$ Discriminator

    Lindblom, Lee


    This paper derives accuracy standards for model gravitational waveforms required to ensure proper use of the $\\chi^2$ discriminator test in gravitational wave (GW) data analysis. These standards are different from previously established requirements for detection and waveform parameter measurement based on signal-to-noise optimization. We present convenient formulae both for evaluating and interpreting the contribution of model errors to measured $\\chi^2$ values. Motivated by these formula, we also present an enhanced, complexified variant of the standard $\\chi^2$ statistic used in GW searches. While our results are not directly relevant to current searches (which use the $\\chi^2$ test only to veto signal candidates with extremely high $\\chi^2$ values), they could be useful in future GW searches and as figures of merit for model gravitational waveforms.

  2. A 10 tesla table-top controlled waveform magnet.

    Roy Choudhury, Aditya N; Venkataraman, V


    Controlled waveform magnets (CWMs) are a class of pulsed magnets whose pulse shape with time can be programmed by the user. With a CWM, the user gains control not only over the magnitude of the field but also over its rate of change. In this work we present a table-top CWM, driven by a capacitor bank, capable of producing virtually any user-shaped magnetic field waveform up to 10 tesla. Insulated gate bipolar transistor chips have been paralleled to form the high current switch and paralleled chips of SiC Schottky diodes form the crowbar diode module. Sample controlled waveforms including flat-tops up to 10 tesla and some triangular magnetic field pulses have been successfully generated for 10-20 ms with a ripple <1%.

  3. Autocorrelation Properties of OFDM Timing Synchronization Waveforms Employing Pilot Subcarriers

    Oktay Üreten


    Full Text Available We investigate the autocorrelation properties of timing synchronization waveforms that are generated by embedded frequency domain pilot tones in orthogonal frequency division multiplex (OFDM systems. The waveforms are composed by summing a selected number of OFDM subcarriers such that the autocorrelation function (ACF of the resulting time waveform has desirable sidelobe behavior. Analytical expressions for the periodic and aperiodic ACF sidelobe energy are derived. Sufficient conditions for minimum and maximum aperiodic ACF sidelobe energy for a given number of pilot tones are presented. Several useful properties of the pilot design problem, such as invariance under transformations and equivalence of complementary sets are demonstrated analytically. Pilot tone design discussion is expanded to the ACF sidelobe peak minimization problem by including various examples and simulation results obtained from a genetic search algorithm.

  4. Autocorrelation Properties of OFDM Timing Synchronization Waveforms Employing Pilot Subcarriers

    Taşcıoğlu Selçuk


    Full Text Available Abstract We investigate the autocorrelation properties of timing synchronization waveforms that are generated by embedded frequency domain pilot tones in orthogonal frequency division multiplex (OFDM systems. The waveforms are composed by summing a selected number of OFDM subcarriers such that the autocorrelation function (ACF of the resulting time waveform has desirable sidelobe behavior. Analytical expressions for the periodic and aperiodic ACF sidelobe energy are derived. Sufficient conditions for minimum and maximum aperiodic ACF sidelobe energy for a given number of pilot tones are presented. Several useful properties of the pilot design problem, such as invariance under transformations and equivalence of complementary sets are demonstrated analytically. Pilot tone design discussion is expanded to the ACF sidelobe peak minimization problem by including various examples and simulation results obtained from a genetic search algorithm.

  5. Agile high resolution arbitrary waveform generator with jitterless frequency stepping

    Reilly, Peter T. A.; Koizumi, Hideya


    Jitterless transition of the programmable clock waveform is generated employing a set of two coupled direct digital synthesis (DDS) circuits. The first phase accumulator in the first DDS circuit runs at least one cycle of a common reference clock for the DDS circuits ahead of the second phase accumulator in the second DDS circuit. As a phase transition through the beginning of a phase cycle is detected from the first phase accumulator, a first phase offset word and a second phase offset word for the first and second phase accumulators are calculated and loaded into the first and second DDS circuits. The programmable clock waveform is employed as a clock input for the RAM address controller. A well defined jitterless transition in frequency of the arbitrary waveform is provided which coincides with the beginning of the phase cycle of the DDS output signal from the second DDS circuit.

  6. Generating Correlated QPSK Waveforms By Exploiting Real Gaussian Random Variables

    Jardak, Seifallah


    The design of waveforms with specified auto- and cross-correlation properties has a number of applications in multiple-input multiple-output (MIMO) radar, one of them is the desired transmit beampattern design. In this work, an algorithm is proposed to generate quadrature phase shift- keying (QPSK) waveforms with required cross-correlation properties using real Gaussian random-variables (RV’s). This work can be considered as the extension of what was presented in [1] to generate BPSK waveforms. This work will be extended for the generation of correlated higher-order phase shift-keying (PSK) and quadrature amplitude modulation (QAM) schemes that can better approximate the desired beampattern.

  7. Ultra-wideband noise radar based on optical waveform generation

    Grodensky, Daniel; Kravitz, Daniel; Zadok, Avi


    A microwave-photonic, ultra-wideband (UWB) noise radar system is proposed and demonstrated. The system brings together photonic generation of UWB waveforms and fiber-optic distribution. The use of UWB noise provides high ranging resolution and better immunity to interception and jamming. Distribution over fibers allows for the separation the radar-operating personnel and equipment from the location of the front-end. The noise waveforms are generated using the amplified spontaneous emission that is associated with stimulated Brillouin scattering in a standard optical fiber, or with an erbium-doped fiber amplifier. Our experiments demonstrate a proof of concept for an integrated radar system, driven by optically generated UWB noise waveforms of more than 1 GHz bandwidth that are distributed over 10 km distance. The detection of concealed metallic object and the resolving of two targets with the anticipated ranging resolution are reported.

  8. Design of output voltage waveform on magnetic encoder

    Shi Yu E-mail:; Zhang Huaiwu; Jiang Xiangdong; Wen Qiye; Han Baoshan


    A novel design model based on slant multi-phase filter (SMPF) theory is presented. By the theory nth harmonic voltage (n=2nd, 3rd and 4th...(V)) can be reduced easily. Magnetic encoder with sinusoidal output voltage waveform has been developed and sinusoidal output waveform can be easily improved. The minimum of distortion factor was observed when the difference of slant phase is 2{pi}3. This result agrees with SMPF theory value {phi}=4.904 deg. (p=0.8 mm, l=3 mm, {delta}{theta}=2{pi}3]. This result can be widely used in magnetoresistive sensor fields.

  9. Efficient 2d full waveform inversion using Fortran coarray

    Ryu, Donghyun; Kim, ahreum; Ha, Wansoo


    We developed a time-domain seismic inversion program using the coarray feature of the Fortran 2008 standard to parallelize the algorithm. We converted a 2d acoustic parallel full waveform inversion program with Message Passing Interface (MPI) to a coarray program and examined performance of the two inversion programs. The results show that the speed of the waveform inversion program using the coarray is slightly faster than that of the MPI version. The standard coarray lacks features for collective communication; however, it can be improved in following standards since it is introduced recently. The parallel algorithm can be applied for 3D seismic data processing.

  10. Krylov-subspace acceleration of time periodic waveform relaxation

    Lumsdaine, A. [Univ. of Notre Dame, IN (United States)


    In this paper the author uses Krylov-subspace techniques to accelerate the convergence of waveform relaxation applied to solving systems of first order time periodic ordinary differential equations. He considers the problem in the frequency domain and presents frequency dependent waveform GMRES (FDWGMRES), a member of a new class of frequency dependent Krylov-subspace techniques. FDWGMRES exhibits many desirable properties, including finite termination independent of the number of timesteps and, for certain problems, a convergence rate which is bounded from above by the convergence rate of GMRES applied to the static matrix problem corresponding to the linear time-invariant ODE.

  11. A Novel Memory Compress Algorithm for Arbitrary Waveform Generator

    吕铁良; 仇玉林


    A memory compress algorithm for 12-bit Arbitrary Waveform Generator (AWG) is presented and optimized. It can compress waveform memory for a sinusoid to 16× 13hits with a Spurious-Free Dynamic Range (SFDR) 90.7dBc (1/1890 of uncompressed memory at the same SFDR) and to 8× 12bits with a SFDR 79dBc. Its hardware cost is six adders and two multipliers. Exploiting this memory compress technique makes it possible to build a high performance AWG on a chip.

  12. Partitioned Waveform Inversion Applied to Eurasia and Northern Africa

    bedle, H; Matzel, E; Flanagan, M


    This report summarizes the data analysis achieved during Heather Bedle's eleven-week Technical Scholar internship at Lawrence Livermore National Labs during the early summer 2006. The work completed during this internship resulted in constraints on the crustal and upper mantle S-velocity structure in Northern Africa, the Mediterranean, the Middle East, and Europe, through the fitting of regional waveform data. This data extends current raypath coverage and will be included in a joint inversion along with data from surface wave group velocity measurements, S and P teleseismic arrival time data, and receiver function data to create an improved velocity model of the upper mantle in this region. The tectonic structure of the North African/Mediterranean/Europe/Middle Eastern study region is extremely heterogeneous. This region consists of, among others, stable cratons and platforms such as the West Africa Craton, and Baltica in Northern Europe; oceanic subduction zones throughout the Mediterranean Sea where the African and Eurasian plate collide; regions of continental collision as the Arabian Plate moves northward into the Turkish Plate; and rifting in the Red Sea, separating the Arabian and Nubian shields. With such diverse tectonic structures, many of the waveforms were difficult to fit. This is not unexpected as the waveforms are fit using an averaged structure. In many cases the raypaths encounter several tectonic features, complicating the waveform, and making it hard for the software to converge on a 1D average structure. Overall, the quality of the waveform data was average, with roughly 30% of the waveforms being discarded due to excessive noise that interfered with the frequency ranges of interest. An inversion for the 3D S-velocity structure of this region was also performed following the methodology of Partitioned Waveform Inversion (Nolet, 1990; Van der Lee and Nolet, 1997). The addition of the newly fit waveforms drastically extends the range of the

  13. Full waveform modelling and misfit calculation using the VERCE platform

    Garth, Thomas; Spinuso, Alessandro; Casarotti, Emanuele; Magnoni, Federica; Krischner, Lion; Igel, Heiner; Schwichtenberg, Horst; Frank, Anton; Vilotte, Jean-Pierre; Rietbrock, Andreas


    In recent years the increasing resolution of seismic imagining by full waveform inversion has opened new research perspectives and practices. These methods rely on harnessing the computational power of large supercomputers and new storage capabilities, to run large parallel codes to simulate the seismic wave field in three-dimensional geological settings. The VERCE platform is designed to make these full waveform techniques accessible to a far wider spectrum of the seismological community. VERCE empowers a broad base of seismology researchers to harvest the new opportunities provided by well-established high-performance wave simulation codes such as SPECFEM3D. It meets a range of seismic research needs by eliminating the technical difficulties associated with using these codes, allowing users to focus on their research questions. VERCE delivers this power to seismologists through its science gateway, supporting wave simulation codes on each of the provided computing resources. Users can design their waveform simulation scenarios making use of a library of pre-loaded meshes and velocity models, and services for selecting earthquake focal mechanisms, seismic stations and recorded waveforms from existing catalogues, such as the GCMT catalogue, and FDSN data sources. They can also supply their own mesh, velocity model, earthquake catalogue and seismic observations. They can submit the simulations onto different computing resources, where VERCE provides codes that are tuned and supported for those resources. The simulations can currently be run on a range of European supercomputers in the PRACE network, including superMUC at LRZ, GALILEO at CINECA and on selected resources like Drachenfels at SCAI and within the EGI network. The gateway automates and looks after all these stages, but supplies seismologists with a provenance system that allows them to manage a large series of runs, review progress, and explore the results. The platform automates misfit analysis between

  14. Usefulness of color and pulsed Doppler's in the evaluation of surgical portosystemic shunts in pediatric patients; Utilidad del Doppler color y pulsado en la valoracion de los shunts portosistemicos quirurgicos en la edad pediatrica

    Berrocal, T.; Prieto, C.; Cortes, P.; Rodriguez, R.; Pastor, I. [Hospital Universitario La Paz. Madrid (Spain)


    Portosystemic shunts are performed to relieve symptomatic portal hypertension symptomatic or removal pressure in hepatic vascularisation in patients with Budd-Chiari's syndrome. Most surgical portosystemic shunts can be suitably studied by means of ultrasound scan complemented by color and pulsed Dopplers, proved one understands the hemodynamics of the surgical procedures involved. This article demonstrates the usefulness and limitations of the ultrasound scan Duplex Doppler in the evaluation of portosystemic shunts performed on pediatric patients. Pulsed Doppler provides information regarding the nature and direction of blood flow. Color doppler is capable of directly revealing the shunt and, in most cases, permits the anastomosis to be located. The types of shunts that appear include proximal and distal spleno-renal, portocaval and mesocaval. Types of vascular connections are illustrated,s well as expected post-surgical blood flow direction in affected vessels. The ultrasound scanning technique is discussed, as well as the criteria for determining vascular permeability. Also highlighted are the advantages, limitations and diagnostic difficulties associated with the different forms of Doppler. (Author) 17 refs.

  15. Coherent Doppler Lidar for Measuring Altitude, Ground Velocity, and Air Velocity of Aircraft and Spaceborne Vehicles

    Amzajerdian, Farzin (Inventor); Pierrottet, Diego F. (Inventor)


    A Doppler lidar sensor system includes a laser generator that produces a highly pure single frequency laser beam, and a frequency modulator that modulates the laser beam with a highly linear frequency waveform. A first portion of the frequency modulated laser beam is amplified, and parts thereof are transmitted through at least three separate transmit/receive lenses. A second portion of the laser beam is used as a local oscillator beam for optical heterodyne detection. Radiation from the parts of the laser beam transmitted via the transmit/receive lenses is received by the respective transmit/receive lenses that transmitted the respective part of the laser beam. The received reflected radiation is compared with the local oscillator beam to calculate the frequency difference there between to determine various navigational data.

  16. Surgical treatment of an aneurysm of a distal branch of the renal artery.

    Abdalla, Solafah; Pierret, Charles; Ba, Bakar; Mlynski, Amélie; de Kerangal, Xavier; Houlgatte, Alain


    Aneurysms of the renal artery and its branches are rare, but are associated with significant morbimortality due to the absence of clinical symptoms and hemorrhagic risk in the event of rupture. We report the case of a patient with an aneurysm of a distal branch of the right renal artery that measured 25 mm in diameter. The diagnosis and localization were obtained using selective arteriography. Treatment consisted of resection of the aneurysmal sac associated with closure with a saphenous vein patch rather than an endovascular treatment in order to preserve the nephronic capital. Right renal parenchymatous vascularization was satisfactory on arterial echo-Doppler and angioscanner assessment at 1 year.

  17. Penile gangrene in diabetes mellitus with renal failure: A poor prognostic sign of systemic vascular calciphylaxis

    Mayank Mohan Agarwal


    Full Text Available Penile gangrene associated with chronic renal failure is very uncommon. A 52-year-old man with diabetes mellitus, diffuse atherosclerosis, ischemic cardiomyopathy and end-stage renal disease presented with blackening of distal penis for 10 days. His general condition was poor and gangrene of prepuce and glans was noted. Doppler and magnetic-resonance angiography revealed bilateral internal iliac artery obstruction. He underwent trocar suprapubic cystostomy and was planned for partial penectomy. But he died of severe diabetic complications in the interim period. Penile gangrene is a manifestation of widespread vascular calcifications associated with end-stage renal disease and is a marker of poor prognosis.

  18. Ultrasonography with color Doppler and power Doppler in the diagnosis of periapical lesions

    Sumit Goel


    Full Text Available Aim: To evaluate the efficacy of ultrasonography (USG with color Doppler and power Doppler applications over conventional radiography in the diagnosis of periapical lesions. Materials and Methods: Thirty patients having inflammatory periapical lesions of the maxillary or mandibular anterior teeth and requiring endodontic surgery were selected for inclusion in this study. All patients consented to participate in the study. We used conventional periapical radiographs as well as USG with color Doppler and power Doppler for the diagnosis of these lesions. Their diagnostic performances were compared against histopathologic examination. All data were compared and statistically analyzed. Results: USG examination with color Doppler and power Doppler identified 29 (19 cysts and 10 granulomas of 30 periapical lesions accurately, with a sensitivity of 100% for cysts and 90.91% for granulomas and a specificity of 90.91% for cysts and 100% for granulomas. In comparison, conventional intraoral radiography identified only 21 lesions (sensitivity of 78.9% for cysts and 45.4% for granulomas and specificity of 45.4% for cysts and 78.9% for granulomas. There was definite correlation between the echotexture of the lesions and the histopathological features except in one case. Conclusions: USG imaging with color Doppler and power Doppler is superior to conventional intraoral radiographic methods for diagnosing the nature of periapical lesions in the anterior jaws. This study reveals the potential of USG examination in the study of other jaw lesions.

  19. Kidney (Renal) Failure

    ... How is kidney failure treated? What is kidney (renal) failure? The kidneys are designed to maintain proper fluid ... marrow and strengthen the bones. The term kidney (renal) failure describes a situation in which the kidneys have ...

  20. Renal arteries (image)

    A renal angiogram is a test used to examine the blood vessels of the kidneys. The test is performed ... main vessel of the pelvis, up to the renal artery that leads into the kidney. Contrast medium ...

  1. Renal Allograft Torsion: US and CT Imaging Findings of a Rare Posttransplant Complication

    Rohit Dewan


    Full Text Available Vascular torsion is a rare renal transplant complication which requires prompt diagnosis and surgery to salvage allograft function. We report here a case of renal allograft torsion with interesting imaging findings on unenhanced CT and color Doppler ultrasound. A 60-year-old woman with a history of pancreas and kidney transplant presented to the emergency room with nausea, vomiting, abdominal pain, and minimal urine output. Unenhanced CT of the abdomen demonstrated an enlarged and malrotated renal allograft with moderate hydronephrosis. Color Doppler ultrasound demonstrated lack of vascularity within the allograft. The patient was taken urgently to the operating room where the renal allograft was found twisted 360 degrees around the vascular pedicle. After the allograft was detorsed, the color of the kidney returned and the Doppler signals for arterial flow improved. Intraoperative biopsy showed no evidence of infarct or acute cellular rejection. The detorsed kidney was surgically fixed in position in its upper and lower poles. Follow-up ultrasound 1 day later demonstrated normal blood flow to the renal allograft and the serum level of creatinine returned to normal.

  2. Renal Allograft Torsion: US and CT Imaging Findings of a Rare Posttransplant Complication.

    Dewan, Rohit; Dasyam, Anil K; Tan, Henke; Furlan, Alessandro


    Vascular torsion is a rare renal transplant complication which requires prompt diagnosis and surgery to salvage allograft function. We report here a case of renal allograft torsion with interesting imaging findings on unenhanced CT and color Doppler ultrasound. A 60-year-old woman with a history of pancreas and kidney transplant presented to the emergency room with nausea, vomiting, abdominal pain, and minimal urine output. Unenhanced CT of the abdomen demonstrated an enlarged and malrotated renal allograft with moderate hydronephrosis. Color Doppler ultrasound demonstrated lack of vascularity within the allograft. The patient was taken urgently to the operating room where the renal allograft was found twisted 360 degrees around the vascular pedicle. After the allograft was detorsed, the color of the kidney returned and the Doppler signals for arterial flow improved. Intraoperative biopsy showed no evidence of infarct or acute cellular rejection. The detorsed kidney was surgically fixed in position in its upper and lower poles. Follow-up ultrasound 1 day later demonstrated normal blood flow to the renal allograft and the serum level of creatinine returned to normal.

  3. Sonar waveforms for reverberation rejection, part I: theory

    Doist, Y.; Deruz, L.; Been, R.


    The influence of the waveform of the transmitted signal on the signal to reverberation ratio induced at the processing output of a moving sonar array is analysed on an theoretical basis. Three main classes of signals are analysed: wide band signals with a flat spectrum (for instance FM signals), con

  4. Waveform Diversity and Design for Interoperating Radar Systems


    University Di Pisa Department Di Ingegneria Dell Informazione Elettronica, Informatica , Telecomunicazioni Via Girolamo Caruso 16 Pisa, Italy 56122...NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) University Di Pisa Department Di Ingegneria Dell Informazione Elettronica, Informatica ...DIPARTIMENTO DI INGEGNERIA DELL’INFORMAZIONE ELETTRONICA, INFORMATICA , TELECOMUNICAZIONI WAVEFORM DIVERSITY AND DESIGN FOR INTEROPERATING

  5. On the Contribution of Head Waves to Full Waveform Inversion

    Kazei, V.V.; Ponomarenko, A.V.; Troyan, V.N.; Kashtan, B.M.; Mulder, W.A.


    Full waveform inversion suffers from local minima, due to a lack of low frequencies in the data. A reflector below the zone of interest may, however, help in recovering the long-wavelength components of a velocity perturbation, as demonstrated in a paper by Mora. With the Born approximation for the

  6. A nonlinear approach of elastic reflection waveform inversion

    Guo, Qiang


    Elastic full waveform inversion (EFWI) embodies the original intention of waveform inversion at its inception as it is a better representation of the mostly solid Earth. However, compared with the acoustic P-wave assumption, EFWI for P- and S-wave velocities using multi-component data admitted mixed results. Full waveform inversion (FWI) is a highly nonlinear problem and this nonlinearity only increases under the elastic assumption. Reflection waveform inversion (RWI) can mitigate the nonlinearity by relying on transmissions from reflections focused on inverting low wavenumber components of the model. In our elastic endeavor, we split the P- and S-wave velocities into low wavenumber and perturbation components and propose a nonlinear approach to invert for both of them. The new optimization problem is built on an objective function that depends on both background and perturbation models. We utilize an equivalent stress source based on the model perturbation to generate reflection instead of demigrating from an image, which is applied in conventional RWI. Application on a slice of an ocean-bottom data shows that our method can efficiently update the low wavenumber parts of the model, but more so, obtain perturbations that can be added to the low wavenumbers for a high resolution output.

  7. Categorisation of full waveform data provided by laser scanning devices

    Ullrich, Andreas; Pfennigbauer, Martin


    In 2004, a laser scanner device for commercial airborne laser scanning applications, the RIEGL LMS-Q560, was introduced to the market, making use of a radical alternative approach to the traditional analogue signal detection and processing schemes found in LIDAR instruments so far: digitizing the echo signals received by the instrument for every laser pulse and analysing these echo signals off-line in a so-called full waveform analysis in order to retrieve almost all information contained in the echo signal using transparent algorithms adaptable to specific applications. In the field of laser scanning the somewhat unspecific term "full waveform data" has since been established. We attempt a categorisation of the different types of the full waveform data found in the market. We discuss the challenges in echo digitization and waveform analysis from an instrument designer's point of view and we will address the benefits to be gained by using this technique, especially with respect to the so-called multi-target capability of pulsed time-of-flight LIDAR instruments.

  8. Augmented kludge waveforms for detecting extreme-mass-ratio inspirals

    Chua, Alvin J. K.; Moore, Christopher J.; Gair, Jonathan R.


    The extreme-mass-ratio inspirals (EMRIs) of stellar-mass compact objects into massive black holes are an important class of source for the future space-based gravitational-wave detector LISA. Detecting signals from EMRIs will require waveform models that are both accurate and computationally efficient. In this paper, we present the latest implementation of an augmented analytic kludge (AAK) model, publicly available at as part of an EMRI waveform software suite. This version of the AAK model has improved accuracy compared to its predecessors, with two-month waveform overlaps against a more accurate fiducial model exceeding 0.97 for a generic range of sources; it also generates waveforms 5-15 times faster than the fiducial model. The AAK model is well suited for scoping out data analysis issues in the upcoming round of mock LISA data challenges. A simple analytic argument shows that it might even be viable for detecting EMRIs with LISA through a semicoherent template bank method, while the use of the original analytic kludge in the same approach will result in around 90% fewer detections.

  9. Synchronous Generator Model Parameter Estimation Based on Noisy Dynamic Waveforms

    Berhausen, Sebastian; Paszek, Stefan


    In recent years, there have occurred system failures in many power systems all over the world. They have resulted in a lack of power supply to a large number of recipients. To minimize the risk of occurrence of power failures, it is necessary to perform multivariate investigations, including simulations, of power system operating conditions. To conduct reliable simulations, the current base of parameters of the models of generating units, containing the models of synchronous generators, is necessary. In the paper, there is presented a method for parameter estimation of a synchronous generator nonlinear model based on the analysis of selected transient waveforms caused by introducing a disturbance (in the form of a pseudorandom signal) in the generator voltage regulation channel. The parameter estimation was performed by minimizing the objective function defined as a mean square error for deviations between the measurement waveforms and the waveforms calculated based on the generator mathematical model. A hybrid algorithm was used for the minimization of the objective function. In the paper, there is described a filter system used for filtering the noisy measurement waveforms. The calculation results of the model of a 44 kW synchronous generator installed on a laboratory stand of the Institute of Electrical Engineering and Computer Science of the Silesian University of Technology are also given. The presented estimation method can be successfully applied to parameter estimation of different models of high-power synchronous generators operating in a power system.

  10. Notched spectrum: from probing waveforms to receive filters

    Jiang, Yi; Gianelli, Christopher D.


    The increasing demand for wireless data services and communications is expanding the frequency footprint of both civilian and military wireless networks, and hence encroaches upon spectrum traditionally reserved for radar systems. To maximize spectral efficiency, it is desirable for a modern radar system to use waveforms with the ability to fit into tightly controlled spectral regions, which requires the formation of nulls with required notching levels on prescribed frequency stop-bands. Additionally, the waveform should posses a low peak-to-average ratio (PAR), and have good auto-correlation performance. In this work, we propose a novel method for the design of such a waveform using alternating convex optimization. The core module of the proposed algorithm is a fast Fourier transform, which makes the algorithm quite efficient and can handle waveform designs with up to 105 samples. Moreover, our algorithm can achieve a flexible tradeoff between PAR and reduced pass band ripple. A simple application in synthetic aperture radar is considered to highlight the performance of the design algorithm.

  11. Automated microseismic event location using Master-Event Waveform Stacking

    Grigoli, Francesco; Cesca, Simone; Krieger, Lars; Kriegerowski, Marius; Gammaldi, Sergio; Horalek, Josef; Priolo, Enrico; Dahm, Torsten


    Accurate and automated locations of microseismic events are desirable for many seismological and industrial applications. The analysis of microseismicity is particularly challenging because of weak seismic signals with low signal-to-noise ratio. Traditional location approaches rely on automated picking, based on individual seismograms, and make no use of the coherency information between signals at different stations. This strong limitation has been overcome by full-waveform location methods, which exploit the coherency of waveforms at different stations and improve the location robustness even in presence of noise. However, the performance of these methods strongly depend on the accuracy of the adopted velocity model, which is often quite rough; inaccurate models result in large location errors. We present an improved waveform stacking location method based on source-specific station corrections. Our method inherits the advantages of full-waveform location methods while strongly mitigating the dependency on the accuracy of the velocity model. With this approach the influence of an inaccurate velocity model on the results is restricted to the estimation of travel times solely within the seismogenic volume, but not for the entire source-receiver path. We finally successfully applied our new method to a realistic synthetic dataset as well as real data.

  12. A marked point process for modeling lidar waveforms.

    Mallet, Clément; Lafarge, Florent; Roux, Michel; Soergel, Uwe; Bretar, Frédéric; Heipke, Christian


    Lidar waveforms are 1-D signals representing a train of echoes caused by reflections at different targets. Modeling these echoes with the appropriate parametric function is useful to retrieve information about the physical characteristics of the targets. This paper presents a new probabilistic model based upon a marked point process which reconstructs the echoes from recorded discrete waveforms as a sequence of parametric curves. Such an approach allows to fit each mode of a waveform with the most suitable function and to deal with both, symmetric and asymmetric, echoes. The model takes into account a data term, which measures the coherence between the models and the waveforms, and a regularization term, which introduces prior knowledge on the reconstructed signal. The exploration of the associated configuration space is performed by a reversible jump Markov chain Monte Carlo (RJMCMC) sampler coupled with simulated annealing. Experiments with different kinds of lidar signals, especially from urban scenes, show the high potential of the proposed approach. To further demonstrate the advantages of the suggested method, actual laser scans are classified and the results are reported.

  13. Multisource waveform inversion of marine streamer data using normalized wavefield

    Choi, Yun Seok


    Multisource full-waveform inversion based on the L1- and L2-norm objective functions cannot be applied to marine streamer data because it does not take into account the unmatched acquisition geometries between the observed and modeled data. To apply multisource full-waveform inversion to marine streamer data, we construct the L1- and L2-norm objective functions using the normalized wavefield. The new residual seismograms obtained from the L1- and L2-norms using the normalized wavefield mitigate the problem of unmatched acquisition geometries, which enables multisource full-waveform inversion to work with marine streamer data. In the new approaches using the normalized wavefield, we used the back-propagation algorithm based on the adjoint-state technique to efficiently calculate the gradients of the objective functions. Numerical examples showed that multisource full-waveform inversion using the normalized wavefield yields much better convergence for marine streamer data than conventional approaches. © 2013 Society of Exploration Geophysicists.

  14. Applying the Moment Distance Framework to LiDAR Waveforms

    Salas, E. L.; Aguilar-Amuchastegui, N.; Henebry, G. M.


    In the past decade or so, there have only been limited approaches formulated for the analysis of waveform LiDAR data. We illustrate how the Moment Distance (MD) framework can characterize the shape of the LiDAR waveforms using simple, computationally fast, geometric operations. We assess the relationship of the MD metrics to some key waveform landmarks - such as locations of peaks, power of returns, and pseudo-heights - using LVIS datasets acquired over a tropical forest in La Selva, Costa Rica in 1998 and 2005. We also apply the MD framework to 2003 LVIS data from Howland Forest, Maine. We also explore the effects of noise on the MD Index (MDI). Our results reveal that the MDI can capture important dynamics in canopy structure. Movement in the location of the peaks is detected by shifts in the MDI. Because this new approach responds to waveform shape, it is more sensitive to changes of location of peak returns than to the power of the return. Results also suggest a positive relationship between the MDI and the canopy pseudo-height.

  15. Structural similarity regularization scheme for multiparameter seismic full waveform inversion

    Li, M.; Liang, L.; Abubakar, A.; Van den Berg, P.M.


    We introduce a new regularization scheme for multiparameter seismic full-waveform inversion (FWI). Using this scheme, we can constrain spatial variations of parameters which are having a weak sensitivity with the one that having a good sensitivity to the measurement, assuming that these parameters h

  16. On the potential of OFDM enhancements as 5G waveforms

    Berardinelli, Gilberto; Pajukoski, Kari; Lähetkangas, Eeva


    Division Multiplexing (OFDM) and its recently proposed enhancements as 5G waveforms, mainly focusing on their capability to cope with our requirements. Significant focus is given to the novel zero-tail paradigm, which allows boosting the OFDM flexibility while circumventing demerits such as poor spectral...

  17. [Renal leiomyoma. Case report].

    Joual, A; Guessous, H; Rabii, R; Benjelloun, M; Benlemlih, A; Skali, K; el Mrini, M; Benjelloun, S


    The authors report a case of renal leiomyoma observed in a 56-year-old man. This cyst presented in the from of loin pain. Computed tomography revealed a homogeneous renal tumor. Treatment consisted of radical nephrectomy. Histological examination of the specimen showed benign renal leiomyoma.

  18. Renal inflammatory myofibroblastic tumor

    Heerwagen, S T; Jensen, C; Bagi, P


    Renal inflammatory myofibroblastic tumor (IMT) is a rare soft-tissue tumor of controversial etiology with a potential for local recurrence after incomplete surgical resection. The radiological findings in renal IMT are not well described. We report two cases in adults with a renal mass treated...

  19. Laser Doppler anemometer measurements of pulsatile flow in a model carotid bifurcation.

    Ku, D N; Giddens, D P


    Hemodynamics at the human carotid bifurcation is important to the understanding of atherosclerotic plaque initiation and progression as well as to the diagnosis of clinically important disease. Laser Doppler anemometry was performed in a large scale model of an average human carotid. Pulsatile waveforms and physiologic flow divisions were incorporated. Disturbance levels and shear stresses were computed from ensemble averages of the velocity waveform measurements. Flow in the common carotid was laminar and symmetric. Flow patterns in the sinus, however, were complex and varied considerably during the cycle. Strong helical patterns and outer wall flow separation waxed and waned during each systole. The changing flow patterns resulted in an oscillatory shear stress at the outer wall ranging from -13 to 9 dyn cm-2 during systole with a time-averaged mean of only -0.5 dyn cm-2. This contrasts markedly with an inner wall shear stress range of 17-50, (mean 26) dyn cm-2. The region of transient separation was confined to the carotid sinus outer wall with no reverse velocities detected in the distal internal carotid. Notable disturbance velocities were also time-dependent, occurring only during the deceleration phase of systole and the beginning of diastole. The present pulsatile flow studies have aided in identifying hemodynamic conditions which correlate with early intimal thickening and predict the physiologic level of flow disturbances in the bulb of undiseased internal carotid arteries.

  20. Development of the doppler electron velocimeter: theory.

    Reu, Phillip L.


    Measurement of dynamic events at the nano-scale is currently impossible. This paper presents the theoretical underpinnings of a method for making these measurements using electron microscopes. Building on the work of Moellenstedt and Lichte who demonstrated Doppler shifting of an electron beam with a moving electron mirror, further work is proposed to perfect and utilize this concept in dynamic measurements. Specifically, using the concept of ''fringe-counting'' with the current principles of transmission electron holography, an extension of these methods to dynamic measurements is proposed. A presentation of the theory of Doppler electron wave shifting is given, starting from the development of the de Broglie wave, up through the equations describing interference effects and Doppler shifting in electron waves. A mathematical demonstration that Doppler shifting is identical to the conceptually easier to understand idea of counting moving fringes is given by analogy to optical interferometry. Finally, potential developmental experiments and uses of a Doppler electron microscope are discussed.