Tumor vascularity of experimentally induced VX2 carcinoma in the rabbit thigh: evaluation with enhanced power doppler sonography and DSA correlated with histopathologic findings

International Nuclear Information System (INIS)

Kim, Young Hoon; Han, Joon Koo; Chung, Jin Wook; Lee, Kyoung Ho; Kim, Se Hyung; Kim, Seog Joon; Choi, Byung Ihn; Chang, Kee Hyun

2002-01-01

To describe findings of enhanced power Doppler sonography and DSA in experimentally induced VX2 carcinomas in rabbit thigh and to correlate the imaging findings with the histopathologic features. A total of 30 VX2 carcinomas were implanted in rabbit thigh, and after conventional and enhanced power Doppler sonography and DSA, histopathologic examination was performed. Enhanced power Doppler sonography and DSA, were used to determine the distribution pattern of tumor vascularity; to assess its grade and the percentage of a tumor area occupied by vessels, conventional and enhanced power Doppler sonography, as well as DSA, were used. The grade of necrosis and the development of fibrovascular stroma and capsule were histopathologically determined. The findings of power Doppler sonography were compared with those of DSA and the imaging features were correlated with the histopathologic features. At enhanced power Doppler sonography, the signal was either avascular (n=9), peripheral (n=15) or diffuse (n=6), while at DSA, the corresponding totals were eight, fourteen and eight. There was statistically significant corelation between enhanced power Doppler sonogrpahy and DSA, both in their depiction of the distribution of patterns of tumor vascularity and as regards their findings of grade and percentage of vascular area. As determined by both conventional and enhanced power Doppler sonogrpahy, and by DSA, grade of necrosis and the development of fibrovascular stroma and a capsule correlated with grade and the percentage of vascular area. Experimentally induced VX2 carcinomas in rabbit thigh demonstrated various patterns of tumor vascularity, and the findings of enhanced power Doppler sonography correlated with those of DSA. Tumor vascularity, as demonstrated by two imaging modalities, correlated closely with grade of necrosis and the development of fibrovascular stroma and a capsule, as revealed by histopathologic examination

Evaluation of Deep Vein Thrombosis with Multidetector Row CT after Orthopedic Arthroplasty: a Prospective Study for Comparison with Doppler Sonography

International Nuclear Information System (INIS)

Byun, Sung Su; Kim, Youn Jeong; Chun, Yong Sun; Kim, Won Hong; Kim, Jeong Ho; Park, Chul Hi

2008-01-01

This prospective study evaluated the ability of indirect 16-row multidetector CT venography, in comparison with Doppler sonography, to detect deep vein thrombosis after total hip or knee replacement. Sixty-two patients had undergone orthopedic replacement surgery on a total of 30 hip joints and 54 knee joints. The CT venography (scan delay time: 180 seconds; slice thickness/increment: 2/1.5 mm) and Doppler sonography were performed 8 to 40 days after surgery. We measured the z-axis length of the beam hardening artifact that degraded the image quality so that the presence of deep vein thrombosis couldn't be evaluated on the axial CT images. The incidence and location of deep vein thrombosis was analyzed. The diagnostic performance of the CT venograms was evaluated and compared with that of Doppler sonography as a standard of reference. The z-axis length (mean±standard deviation) of the beam hardening artifact was 4.5±0.8 cm in the arthroplastic knees and 3.9±2.9 cm in the arthroplastic hips. Deep vein thrombosis (DVT) was found in the popliteal or calf veins on Doppler sonography in 30 (48%) of the 62 patients. The CT venography has a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 90%, 97%, 96%, 91% and 94%, respectively. The ability of CT venography to detect DVT was comparable to that of Doppler sonography despite of beam hardening artifact. Therefore, CT venography is feasible to use as an alternative modality for evaluating postarthroplasty patients

Evaluation of Deep Vein Thrombosis with Multidetector Row CT after Orthopedic Arthroplasty: a Prospective Study for Comparison with Doppler Sonography

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Byun, Sung Su; Kim, Youn Jeong; Chun, Yong Sun; Kim, Won Hong [Inha University, College of Medicine, Incheon (Korea, Republic of); Kim, Jeong Ho; Park, Chul Hi [Gachon University, Gil Medical Center, Incheon (Korea, Republic of)

2008-02-15

This prospective study evaluated the ability of indirect 16-row multidetector CT venography, in comparison with Doppler sonography, to detect deep vein thrombosis after total hip or knee replacement. Sixty-two patients had undergone orthopedic replacement surgery on a total of 30 hip joints and 54 knee joints. The CT venography (scan delay time: 180 seconds; slice thickness/increment: 2/1.5 mm) and Doppler sonography were performed 8 to 40 days after surgery. We measured the z-axis length of the beam hardening artifact that degraded the image quality so that the presence of deep vein thrombosis couldn't be evaluated on the axial CT images. The incidence and location of deep vein thrombosis was analyzed. The diagnostic performance of the CT venograms was evaluated and compared with that of Doppler sonography as a standard of reference. The z-axis length (mean{+-}standard deviation) of the beam hardening artifact was 4.5{+-}0.8 cm in the arthroplastic knees and 3.9{+-}2.9 cm in the arthroplastic hips. Deep vein thrombosis (DVT) was found in the popliteal or calf veins on Doppler sonography in 30 (48%) of the 62 patients. The CT venography has a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 90%, 97%, 96%, 91% and 94%, respectively. The ability of CT venography to detect DVT was comparable to that of Doppler sonography despite of beam hardening artifact. Therefore, CT venography is feasible to use as an alternative modality for evaluating postarthroplasty patients.

Visualization of the Origin of the Vertebral Arteries with Color Doppler Sonography

International Nuclear Information System (INIS)

Yoon, Seok Hwan; Lee, Won Hong; Lee, Dae Hyung

2009-01-01

Atherosclerotic disease at the origin of the vertebral arteries is one of the risk factors for vertebrobasilar ischemic disease. Assessment and visualization of the origin of the vertebral arteries with color doppler sonography is a non-trivial task. The aim of this study is to increase the visualization rate of the origin of the vertebral arteries with color doppler sonography. Color doppler sonography for the vertebral arteries included carotid arteries was performed to 198 patients. We first examined the vertebral artery in the upper neck in the direction of the subclavian artery to distinguish its origin more easily. If the vertebral artery origin was not visualized in natural position, the examiner pushed the transducer toward a clavicle or pushed the shoulder of patient by the other hand. The technical methods for visualization of the vertebral artery origin were classified into three grades: natural position, pushing the transducer, and pushing the shoulder of patient according to the depth (3.0 cm and shallower, deeper than 3.0 cm) of the origin. The origin of the vertebral arteries could be visualized in 97% on the right and in 92% on the left. The origin of the vertebral arteries could be visualized in 98.6%, 1.4%, and 0.0% in natural position, pushing the transducer, and pushing the shoulder of patient, respectively, at shallower than 3.0 cm on the right side. The origin of the vertebral arteries could be visualized in 81.2%, 14.6%, and 4.2% in natural position, pushing the transducer, and pushing the shoulder of patient, respectively, at deeper than 3.0 cm on the right side. The origin of the vertebral arteries could be visualized in 85.4%, 10.7%, and 3.9% in natural position, pushing the transducer, and pushing the shoulder of patient, respectively, at shallower than 3.0 cm on the left side. The origin of the vertebral arteries could be visualized in 55.7%, 30.4%, and 13.9% in natural position, pushing the transducer, and pushing the shoulder of

Validation of color Doppler sonography for evaluating relative displacement between the flexor tendon and subsynovial connective tissue.

Science.gov (United States)

Tat, Jimmy; Kociolek, Aaron M; Keir, Peter J

2015-04-01

A common pathologic finding in carpal tunnel syndrome is fibrosis and thickening of the subsynovial connective tissue. This finding suggests an etiology of excessive shear forces, with relative longitudinal displacement between the flexor tendon and adjacent subsynovial connective tissue. The purpose of this study was to validate color Doppler sonography for measurement of tendon displacement over time. Eight unmatched fresh frozen cadaver arms were used to evaluate color Doppler sonography for measurement of tendon displacement. The middle flexor digitorum superficialis tendon was moved through a physiologic excursion of 20 mm at 3 different tendon velocities (50, 100, and 150 mm/s). We found that color Doppler sonography provided accurate measurement of tendon displacement, with absolute errors of -0.05 mm (50 mm/s), -1.24 mm (100 mm/s), and -2.36 mm (150 mm/s) on average throughout the tendon excursion range. Evaluating relative displacement between the tendon and subsynovial connective tissue during finger flexion-extension movements also offered insight into the gliding mechanism of the subsynovial connective tissue. During flexion, we observed a curvilinear increase in relative displacement, with greater differential motion at the end range of displacement, likely due to the sequential stretch of the fibrils between successive layers of the subsynovial connective tissue. In extension, there was a linear return in relative displacement, suggesting a different unloading mechanism characterized by uniform relaxation of fibrils. We demonstrated the validity of color Doppler displacement for use in the evaluation of relative motion. Color Doppler sonography is useful in our understanding of the behavior of the subsynovial connective tissue during tendon excursion, which may elucidate the role of finger motion in the etiology of shear injury. © 2015 by the American Institute of Ultrasound in Medicine.

A novel decision tree approach based on transcranial Doppler sonography to screen for blunt cervical vascular injuries.

Science.gov (United States)

Purvis, Dianna; Aldaghlas, Tayseer; Trickey, Amber W; Rizzo, Anne; Sikdar, Siddhartha

2013-06-01

Early detection and treatment of blunt cervical vascular injuries prevent adverse neurologic sequelae. Current screening criteria can miss up to 22% of these injuries. The study objective was to investigate bedside transcranial Doppler sonography for detecting blunt cervical vascular injuries in trauma patients using a novel decision tree approach. This prospective pilot study was conducted at a level I trauma center. Patients undergoing computed tomographic angiography for suspected blunt cervical vascular injuries were studied with transcranial Doppler sonography. Extracranial and intracranial vasculatures were examined with a portable power M-mode transcranial Doppler unit. The middle cerebral artery mean flow velocity, pulsatility index, and their asymmetries were used to quantify flow patterns and develop an injury decision tree screening protocol. Student t tests validated associations between injuries and transcranial Doppler predictive measures. We evaluated 27 trauma patients with 13 injuries. Single vertebral artery injuries were most common (38.5%), followed by single internal carotid artery injuries (30%). Compared to patients without injuries, mean flow velocity asymmetry was higher for single internal carotid artery (P = .003) and single vertebral artery (P = .004) injuries. Similarly, pulsatility index asymmetry was higher in single internal carotid artery (P = .015) and single vertebral artery (P = .042) injuries, whereas the lowest pulsatility index was elevated for bilateral vertebral artery injuries (P = .006). The decision tree yielded 92% specificity, 93% sensitivity, and 93% correct classifications. In this pilot feasibility study, transcranial Doppler measures were significantly associated with the blunt cervical vascular injury status, suggesting that transcranial Doppler sonography might be a viable bedside screening tool for trauma. Patient-specific hemodynamic information from transcranial Doppler assessment has the potential to alter

Time series analysis of continuous-wave coherent Doppler Lidar wind measurements

International Nuclear Information System (INIS)

Sjoeholm, M; Mikkelsen, T; Mann, J; Enevoldsen, K; Courtney, M

2008-01-01

The influence of spatial volume averaging of a focused 1.55 μm continuous-wave coherent Doppler Lidar on observed wind turbulence measured in the atmospheric surface layer over homogeneous terrain is described and analysed. Comparison of Lidar-measured turbulent spectra with spectra simultaneously obtained from a mast-mounted sonic anemometer at 78 meters height at the test station for large wind turbines at Hoevsoere in Western Jutland, Denmark is presented for the first time

Diagnosis of Cervical Abortion by TransvaginaI Color Doppler Sonography : A Case Report

International Nuclear Information System (INIS)

Lee, Eun Ju; Ryu, Hee Sug; Ji, Hoon; Suh, Jung Ho

1995-01-01

Cervical abortion is a spontaneous abortion of an intrauterine pregnancy into the cervical canal where the abortus is retained by a closed external os, causing distension of the cervical canal. Cervical abortion should be distinguished from the cervical pregnancy. We present a case of cervical abortion diagnosed preoperatively by transvaginal sonography and color doppler imaging, and treated by dilatation and curettage. Charateristic transvaginal sonographic findings and identification of subtrophoblastic blood flow by color doppler imaging could allow differentiation of the cevical aborition from the cervical pregnancy

Challenges in noise removal from Doppler spectra acquired by a continuous-wave lidar

DEFF Research Database (Denmark)

Angelou, Nikolas; Foroughi Abari, Farzad; Mann, Jakob

2012-01-01

are presented. A method for determining the background noise spectrum without interrupting the transmission of the laser beam is described. Moreover, the dependency between the determination of the threshold of a Doppler spectrum with low signal-to-noise ratios and the characteristics of the wind flow......This paper is focused on the required post processing of Doppler spectra, acquired from a continuous-wave coherent lidar at high sampling rates (400 Hz) and under rapid scanning of the laser beam. In particular, the necessary steps followed for extracting the wind speed from such Doppler spectra...... are investigated and a systematic approach for removing the noise is outlined. The suggested post processing procedures are applied to two sample time series acquired by a short-range WindScanner during one second each....

Abnormal uterine bleeding due to vascular abnormality caused by D and E : doppler sonography for diagnosis and transcatheter arterial embolization for treatment

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Kim, Yong Jo; Heo, Chan; Jung, Tae Gun; Kim, Gi Sung; Kwon, Hyeok Po; Lee, Sang Kwon; Kwon, Jung Hyeok [Dongkang Hospital, Ulsan (Korea, Republic of); Lee, Yeong Hwan [Taegu Catholic Univ. School of Medicine, Taegu (Korea, Republic of)

1996-06-01

We attempted to evaluate the usefulness of Doppler sonography in the diagnosis of uterine vascular abnormality caused by previous D and E, and to report that transarterial embolization is an excellent treatment modality. We analyzed gray-scale US, color/duplex Doppler US and angiographic findings in seven patients with radiologically proven uterine vascular abnormality. Two of the seven cases were pseudoaneurysms and five of the seven cases were AVMs. n one of the AVMS, two small pseudoaneurysms were combined. In all cases, transarterial embolizations using 3 mm coil or/and gelfoam particles were performed. Follow-up US studies, including color Doppler US, were performed. on color/duplex Doppler sonography, two cases of pseudoaneurysm showed blood pools with turbulent arterial flow, and five cases of AVM showed asymmetrically increased cascularity, with vailable high velocities composed of the pulsatile arterial flow, with a high diastolic component. on angiography, the former showed pseudoaneruysmal sacs, and the latter densely opacified vascular tangles. No more abnormal uterine bleeding was shown following transarterial embolization in all cases. Color/duplex Doppler sonography was valuable in the diagnosis or treatment of abnormal uterine bleeding caused by uterine vascular abnormality such as acquired AVM or pseudoaneruysm.

Abnormal uterine bleeding due to vascular abnormality caused by D and E : doppler sonography for diagnosis and transcatheter arterial embolization for treatment

International Nuclear Information System (INIS)

Kim, Yong Jo; Heo, Chan; Jung, Tae Gun; Kim, Gi Sung; Kwon, Hyeok Po; Lee, Sang Kwon; Kwon, Jung Hyeok; Lee, Yeong Hwan

1996-01-01

We attempted to evaluate the usefulness of Doppler sonography in the diagnosis of uterine vascular abnormality caused by previous D and E, and to report that transarterial embolization is an excellent treatment modality. We analyzed gray-scale US, color/duplex Doppler US and angiographic findings in seven patients with radiologically proven uterine vascular abnormality. Two of the seven cases were pseudoaneurysms and five of the seven cases were AVMs. n one of the AVMS, two small pseudoaneurysms were combined. In all cases, transarterial embolizations using 3 mm coil or/and gelfoam particles were performed. Follow-up US studies, including color Doppler US, were performed. on color/duplex Doppler sonography, two cases of pseudoaneurysm showed blood pools with turbulent arterial flow, and five cases of AVM showed asymmetrically increased cascularity, with vailable high velocities composed of the pulsatile arterial flow, with a high diastolic component. on angiography, the former showed pseudoaneruysmal sacs, and the latter densely opacified vascular tangles. No more abnormal uterine bleeding was shown following transarterial embolization in all cases. Color/duplex Doppler sonography was valuable in the diagnosis or treatment of abnormal uterine bleeding caused by uterine vascular abnormality such as acquired AVM or pseudoaneruysm

Impact of sonography in gouty arthritis: Comparison with conventional radiography, clinical examination, and laboratory findings

International Nuclear Information System (INIS)

Schueller-Weidekamm, Claudia; Schueller, Gerd; Aringer, Martin; Weber, Michael; Kainberger, Franz

2007-01-01

Objective: To explore the typical sonographic features of gray-scale and Power Doppler of acute and chronic gouty arthritis in conjunction with radiographic, clinical, and laboratory findings. Materials and methods: All hand, finger, and toe joints of 19 patients with acute and chronic gout were examined with gray-scale and Power Doppler sonography. The number and size of bone changes detected with sonography was compared to radiographic findings. Vascularization of the synovial tissue was scored on Power Doppler (grades 0-3), and was compared with clinical appearance, including swelling, tenderness, and redness (grades 0-3). Results: In acute gout, mild to moderate echogenic periarticular nodules with sonotransmission and hypervascularization of the edematous surrounding soft tissue were found. In chronic gout, tophaceous nodules completely blocked transmission of US wave, leading to strong reflexion and dorsal shadowing in a minority of cases. No significant difference in the detection of large bone changes (>2 mm) was found between sonography and radiography. However, gray-scale sonography was significantly more sensitive in the detection of small bone changes (p < 0.001). Power Doppler scores were statistically significantly higher than clinical examination scores (p < 0.001). Discussion: Sonography is superior to radiographs in evaluating small bone changes. The inflammatory process in joints can be better detected with Power Doppler sonography than with clinical examination. Typical sonographic appearance of acute and in particular of chronic gout might provide clues on gouty arthritis that adds to the information available from conventional radiography, clinical, and laboratory findings

Impact of sonography in gouty arthritis: Comparison with conventional radiography, clinical examination, and laboratory findings

Energy Technology Data Exchange (ETDEWEB)

Schueller-Weidekamm, Claudia [Department of Diagnostic Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria)]. E-mail: claudia.schueller-weidekamm@meduniwien.ac.at; Schueller, Gerd [Department of Diagnostic Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Aringer, Martin [Department of Rheumatology, Internal Medicine III, Medical University of Vienna (Austria); Weber, Michael [Department of Diagnostic Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Kainberger, Franz [Department of Diagnostic Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria)

2007-06-15

Objective: To explore the typical sonographic features of gray-scale and Power Doppler of acute and chronic gouty arthritis in conjunction with radiographic, clinical, and laboratory findings. Materials and methods: All hand, finger, and toe joints of 19 patients with acute and chronic gout were examined with gray-scale and Power Doppler sonography. The number and size of bone changes detected with sonography was compared to radiographic findings. Vascularization of the synovial tissue was scored on Power Doppler (grades 0-3), and was compared with clinical appearance, including swelling, tenderness, and redness (grades 0-3). Results: In acute gout, mild to moderate echogenic periarticular nodules with sonotransmission and hypervascularization of the edematous surrounding soft tissue were found. In chronic gout, tophaceous nodules completely blocked transmission of US wave, leading to strong reflexion and dorsal shadowing in a minority of cases. No significant difference in the detection of large bone changes (>2 mm) was found between sonography and radiography. However, gray-scale sonography was significantly more sensitive in the detection of small bone changes (p < 0.001). Power Doppler scores were statistically significantly higher than clinical examination scores (p < 0.001). Discussion: Sonography is superior to radiographs in evaluating small bone changes. The inflammatory process in joints can be better detected with Power Doppler sonography than with clinical examination. Typical sonographic appearance of acute and in particular of chronic gout might provide clues on gouty arthritis that adds to the information available from conventional radiography, clinical, and laboratory findings.

Flow angle dependent photoacoustic Doppler power spectra under intensity-modulated continuous wave laser excitation

Directory of Open Access Journals (Sweden)

Yu Tong

2016-02-01

Full Text Available Photoacoustic Doppler (PAD power spectra showing an evident Doppler shift represent the major characteristics of the continuous wave-excited or burst wave-excited versions of PAD flow measurements. In this paper, the flow angle dependences of the PAD power spectra are investigated using an experiment setup that was established based on intensity-modulated continuous wave laser excitation. The setup has an overall configuration that is similar to a previously reported configuration, but is more sophisticated in that it accurately aligns the laser illumination with the ultrasound detection process, and in that it picks up the correct sample position. In the analysis of the power spectra data, we find that the background power spectra can be extracted by combining the output signals from the two channels of the lock-in amplifier, which is very useful for identification of the PAD power spectra. The power spectra are presented and analyzed in opposite flow directions, at different flow speeds, and at different flow angles. The power spectra at a 90° flow angle show the unique properties of symmetrical shapes due to PAD broadening. For the other flow angles, the smoothed power spectra clearly show a flow angle cosine relationship.

Response of a Doppler canceling system to plane gravitational waves

International Nuclear Information System (INIS)

Caporali, A.

1982-01-01

This paper discusses the interaction of long periodic gravitational waves with a three-link microwave system known as the Doppler canceling system. This system, which was developed for gravitational red-shift experiment, uses one-way and two-way Doppler information to construct the beat signal of two reference oscillators moving with respect to each other. The geometric-optics approximation is used to derive the frequency shift produced on a light signal propagating in a gravitational-wave space-time. The signature left on the Doppler-canceled beat by bursts and continuous gravitational waves is analyzed. A comparison is made between the response to gravitational waves of the Doppler canceling system and that of a (NASA) Doppler tracking system which employs two-way, round-trip radio waves. A threefold repetition of the gravitational wave form is found to be a common feature of the response functions of both systems. These two functions otherwise exhibit interesting differences

Diagnosis of Pentalogy of Cantrell in the First Trimester Using Transvaginal Sonography and Color Doppler

Directory of Open Access Journals (Sweden)

Ayşe Figen Türkçapar

2015-01-01

Full Text Available We report the prenatal diagnosis of Cantrell syndrome in the first trimester. During a routine transabdominal ultrasonographic examination, a midline supraumbilical abdominal wall defect including herniated liver and ectopia cordis with a large omphalocele containing the intestines and cystic hygroma was incidentally identified at the 12th week of gestation. A transvaginal sonography examination revealed a severe lumbosacral scoliosis in addition to the inability to visualize the abdominal aorta which was indicative of a severe intracardiac defect. The parents opted for pregnancy to be terminated. In this case report, we discuss the complementary role of transvaginal sonography and Doppler imaging in the diagnosis of Cantrell syndrome in early pregnancy.

Usefulness of hemodynamically distribution of intranodal vessels in differentiating metastatic neck lymph nodes-value of color doppler and spectral wave sonogram

International Nuclear Information System (INIS)

Mumtaz, U.

2017-01-01

Objective: To evaluate the diagnostic assessment of enlarged lymph nodes, based on its perfusion pattern by taking tissue diagnosis as gold standard. Study Design: Analytical study. Place and Duration of Study: Departments of Radiology and Pathology, PIMS Hospital, Islamabad, from February to May 2016. Methodology: Color sonography of patients with clinically, palpable cervical lymph nodes were carried by senior trainee under the supervision of senior radiologist. Ultrasound guided tissue diagnosis was obtained in all suspected malignant cases. Histopathology was taken as the gold standard for determining accuracy. Results: Accuracy, sensitivity and specificity, positive and negative predictive values of color Doppler ultrasound in detecting malignant cervical lymphadenopathy was found to be 88.46%, 86.05%, 79.31% and 92.50%, respectively with diagnostic accuracy of 86.95%, when intranodal vascular pattern on color Doppler imaging was analyzed. Using spectral wave indexes, the same values were 92.31%, 90.70%, 85.71%, 95.12%, respectively with overall diagnostic accuracy of 91.30%. Conclusion: Color Doppler sonography is much sensitive borderline than grey scale findings alone. Furthermore, lymph nodes appearing in the detection of malignant nodes on grey scale images can be reliably diagnosed on Doppler scan. (author)

Low-Frequency Gravitational Wave Searches Using Spacecraft Doppler Tracking

Directory of Open Access Journals (Sweden)

Armstrong J. W.

2006-01-01

Full Text Available This paper discusses spacecraft Doppler tracking, the current-generation detector technology used in the low-frequency (~millihertz gravitational wave band. In the Doppler method the earth and a distant spacecraft act as free test masses with a ground-based precision Doppler tracking system continuously monitoring the earth-spacecraft relative dimensionless velocity $2 Delta v/c = Delta u/ u_0$, where $Delta u$ is the Doppler shift and $ u_0$ is the radio link carrier frequency. A gravitational wave having strain amplitude $h$ incident on the earth-spacecraft system causes perturbations of order $h$ in the time series of $Delta u/ u_0$. Unlike other detectors, the ~1-10 AU earth-spacecraft separation makes the detector large compared with millihertz-band gravitational wavelengths, and thus times-of-flight of signals and radio waves through the apparatus are important. A burst signal, for example, is time-resolved into a characteristic signature: three discrete events in the Doppler time series. I discuss here the principles of operation of this detector (emphasizing transfer functions of gravitational wave signals and the principal noises to the Doppler time series, some data analysis techniques, experiments to date, and illustrations of sensitivity and current detector performance. I conclude with a discussion of how gravitational wave sensitivity can be improved in the low-frequency band.

Transcranial Doppler sonography in children: Review of a seven-year experience

International Nuclear Information System (INIS)

Hirsch, Wolfgang; Hiebsch, Wolfgang; Teichler, Heike; SchlUeter, Andreas

2002-01-01

AIM: We report the use of transcranial Doppler sonography (TCD) examinations in children (mean age 12.7 years; range 0.5-18 years) without an open fontanelle, using TCD equipment with a 2 MHz pulse wave transducer. Our results over a 7-year period are described. MATERIAL AND METHODS: A total of 858 children were referred from the paediatric outpatient department. All patients were divided into three groups according to the reason for referral. RESULTS: We found positive pathological results in the following: (1) headache and orthostatic dysregulation (0.4%, three out of 728); (2) acute neurological symptoms (5.4%, six out of 112); (3) other indications (22.2%, four out of 18). The positive predictive value of finding an abnormality was very low (0.50) . CONCLUSION: TCD examination is ineffective in children with non-specific headache or orthostatic dysregulation due to the specific limitations of this method. We found a higher percentage of abnormal results in children referred for other indications. However, since these children usually undergo MR imaging (and MR angiography, if necessary), in our opinion the TCD examination does not add any additional information. The value of TCD in children is not in the primary diagnosis of disease but in the follow up of known vascular processes (e.g. stenoses) or in chronic diseases including angiitis and sickle cell disease. Hirsch, W. et al. (2002)

Deep vein thrombosis of lower extremity: What is the most important finding in duplex Doppler sonography

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Kim, Yong Soo; Koh, Byung Hee; Cho, On Koo; Rhim, Hyun Chul; Seo, Heung Suk; Hahm, Chang Kok; Kwak, Jin Young [Hanyang University College of Medicine, Seoul (Korea, Republic of)

1993-12-15

The positive findings of deep vein thrombosis on duplex Doppler ultrasonography such as intraluminal clot,non-compressibility of the venous lumen and abnormal or absent Doppler shift signal are well known. However, relatively hypoechoic thrombus is not always seen in sonography, and the vein is frequently compressible in partial thrombosis. In order to evaluate the most common and important findings of deep vein thrombosis, we analysed the findings at duplex Doppler ultrasound in 19 patients and compared the results with those of contrast venography in 11 patients. Duplex Doppler ultrasound examination of the common femoral and popliteal veins was performed for one extremity in 14 patients, and for both extremities in 5 (total 24 extremities). Contrast venography was performed for one extremity in 7 patients, and for both sides in 4 (total 15 extremities).Thrombosis was seen in 45.8%, non-compressibility of lumen in 75%, absent or decreased Doppler signal from common femoral vein in 95.8%. Thrombosis was seen in 41.7%, non-compressibility of lumen in 70.8%, absent or decreased Doppler shift signal from popliteal vein in 95.8%. We conclude that abnormal or absent Doppler shift signal is the most sensitive and important finding of the deep vein thrombosis

[Changes of renal blood flow during organ-associated foot reflexology measured by color Doppler sonography].

Science.gov (United States)

Sudmeier, I; Bodner, G; Egger, I; Mur, E; Ulmer, H; Herold, M

1999-06-01

Using colour Doppler sonography blood flow changes of the right kidney during foot reflexology were determined in a placebo-controlled, double-blind, randomised study. 32 healthy young adults (17 women, 15 men) were randomly assigned to the verum or placebo group. The verum group received foot reflexology at zones corresponding to the right kidney, the placebo group was treated on other foot zones. Before, during and after foot reflexology the blood flow of three vessels of the right kidney was measured using colour Doppler sonography. Systolic peak velocity and end diastolic peak velocity were measured in cm/s, and the resistive index, a parameter of the vascular resistance, was calculated. The resistive index in the verum group showed a highly significant decrease (p foot reflexology. There was no difference between men and women and no difference between smokers and non-smokers. Verum and placebo group significantly differed concerning alterations of the resistive index both between the measuring points before versus during foot reflexology (p = 0.002) and those during versus after foot reflexology (p = 0.031). The significant decrease of the resistive index during foot reflexology in the verum group indicates a decrease of flow resistance in renal vessels and an increase of renal blood flow. These findings support the hypothesis that organ-associated foot reflexology is effective in changing renal blood flow during therapy.

Theoretical and experimental signal-to-noise ratio assessment in new direction sensing continuous-wave Doppler lidar

DEFF Research Database (Denmark)

Pedersen, Anders Tegtmeier; Foroughi Abari, Farzad; Mann, Jakob

2014-01-01

A new direction sensing continuous-wave Doppler lidar based on an image-reject homodyne receiver has recently been demonstrated at DTU Wind Energy, Technical University of Denmark. In this contribution we analyse the signal-to-noise ratio resulting from two different data processing methods both...... leading to the direction sensing capability. It is found that using the auto spectrum of the complex signal to determine the wind speed leads to a signal-to-noise ratio equivalent to that of a standard self-heterodyne receiver. Using the imaginary part of the cross spectrum to estimate the Doppler shift...... has the benefit of a zero-mean background spectrum, but comes at the expense of a decrease in the signal-to noise ratio by a factor of √2....

[Can TOF MRA replace duplex and Doppler sonography in preoperative assessment of the carotid arteries? A prospective comparison and review of the literature].

Science.gov (United States)

Krappel, F A; Bauer, E; Harland, U

2002-01-01

To examine the quality and usefulness of time-of-flight MR-angiography and duplex-doppler sonography, respectively, in assessment of the extracranial arteries before cervical spine operations. Patients scheduled for operations of the cervical spine had an MRI plus TOF as well as a duplex and Doppler scan. At the time of the examination the radiologist and the neurologist in charge were blinded for the study. Endpoints were not only the accuracy of the procedures but more so which method improved the preoperative process most. Twenty patients were examined so far. Only in one case did the result differ when a complete occlusion diagnosed sonographically was judged as a severe stenosis on MRA. One patient did not tolerate the MRA for the extra 5 minutes necessary, therefore a contrast-enhanced MRA was performed. MRA eased the preoperative process as imaging of the pathology and the carotids were realised in one step. The costs were slightly higher for MRA than for duplex-doppler sonography. TOF-MRA can replace the duplex-doppler examination in the preoperative assessment of the carotids and has the potential to streamline the preoperative time schedule. Similar to duplex and doppler, in order to be accurate enough the method requires a high degree of expertise from the radiologist.

A method for the automated assessment of temporal characteristics of functional hemispheric lateralization by transcranial Doppler sonography.

Science.gov (United States)

Deppe, M; Knecht, S; Lohmann, H; Ringelstein, E B

2004-07-01

Transcranial Doppler sonography (TCD) can guide and complement investigations based on functional magnetic resonance and positron emission tomography imaging by providing continuous information on cerebral perfusion changes correlated to cerebral activation. So far, however, the role of functional TCD has been limited by a lack of sensitivity. Here, the authors present an outline of a method that increases the potential of TCD to detect perfusion changes within a vascular territory. Sensitivity on the order of 1% can be achieved by transformation of Doppler envelope curves, which accounts for systemic quasi-periodic and irregular spontaneous blood flow modulations and artificial disturbances related to the recording. A statistical technique is introduced that allows the automatic detection of time periods of significant hemispheric lateralization in evoked flow studies. Furthermore, an index of laterality is defined quantifying the extent of hemispheric dominance during stimulus processing. The analysis technique described in this article has been successfully employed in recent examinations on vision, motor activation, language, language recovery, and other cognitive tasks. The novel functional TCD technique permits valid and reproducible assessments of the temporal characteristics of functional hemispheric lateralization.

Renal vein doppler sonography in rabbits with acute ureteral obstruction: usefulness of impedance index of renal vein

International Nuclear Information System (INIS)

Sohn, Kyung Myung; Chung, Su Kyo; Lee, Sung Yong

2004-01-01

To evaluate the usefulness of the impedance index of the renal vein for the diagnosis of acute obstructive uropathy in rabbits. Ligation of the left ureter was done in 12 rabbits. Doppler sonography of the interlobar veins in both kidneys was checked before and 30 minutes, 1, 3, 6, 9 and 24 hours after ureteral ligation. The venous impedance index [(peak flow signal-least flow signal)/peak flow signal] was compared between the obstructed and non-obstructed kidneys for all periods. The change in the impedance index after ureteral ligation was also compared between the obstructed and non-obstructed kidneys. A decrease in the impedance index of the intrarenal vein was observed starting from 30 mins atter ureteral ligation, and the index remained low up to 24 hours after ureteral ligation. The obstructed kidneys had a significantly lower impedance index than the contralateral kidneys for all six of the postligation measurements (p< 0.05). There were significant differences in the change of impedance index after ureteral ligation between the obstructed and non-obstructed kidneys (p< 0.05). The impedance index of the intrarenal vein was significantly decreased in the obstructed kidneys. The measurement of the impedance index of the intrarenal vein using Doppler sonography could provide a useful method of diagnosing obstructive uropathy

Acute testicular torsion in children: the role of sonography in the diagnostic workup.

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Gunther, P; Schenk, J P; Wunsch, R; Holland-Cunz, S; Kessler, U; Troger, J; Waag, K L

2006-11-01

Acute testicular torsion in children is an emergency and has to be diagnosed urgently. Doppler sonography is increasingly used in imaging the acute scrotum. Nevertheless, in uncertain cases, surgical exploration is required. In this study, we attempted to define the role of Doppler sonography in the diagnostic workup of the acutely painful scrotum. All patients admitted between 1999 and 2005 with acute scrotal pain were included. After clinical assessment, patients were imaged by Doppler sonography with a ''high-end'' instrument. In cases of absent arterial perfusion of the testis in Doppler sonography, surgical exploration was carried out. Patients with unaffected perfusion were followed clinically by ultrasound for up to 2 years. Sixty-one infants and children aged 1 day to 17 years (median: 7.9 years) were included. In 14 cases, sonography demonstrated absent central perfusion, with abnormal parenchymal echogenicity in six. Absence of venous blood flow together with reduction of central arterial perfusion was found in one infant. In these 15 patients, surgical exploration confirmed testicular torsion. Among the other 46 patients, we found four cases with increased testicular perfusion and 27 with increased perfusion of the epididymis. In one infant, a testicular tumour was found sonographically, and orchiectomy confirmed diagnosis of a teratoma. Follow-up examinations of the conservatively treated patients showed good clinical outcome with physiologic central perfusion as well as normal echogenic pattern of both testes. No case of testicular torsion was missed. By means of Doppler sonography, an unequivocal statement regarding testicular perfusion was possible in all cases. The initial Doppler diagnosis was confirmed by operative evaluation and follow-up ultrasound. Testicular torsion can therefore be excluded by correctly performed ultrasound with modern equipment.

Renal transplantation: Sonography and Doppler assessment of transplanted kidneys in adult Sudanese patients

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Moawia Gameraddin

2017-06-01

Full Text Available Background Every year, thirty-five thousand patients receive renal transplants worldwide. Kidney transplant provides better quality of life and reduced morbidity. Doppler and sonography were the best imaging modalities for evaluation. Aims To assess the sonographic findings of renal allograft and to determine the correlation between Doppler resistive index and size of allograft and echogenicity. Methods This was a cross-sectional study conducted in Khartoum State from January to August 2016. A total of 86 patients with known transplanted kidneys were scanned with ultrasound using 3MHz and 5MHz transducers. The age was categorized into four groups and so the Doppler indices. Descriptive statistics used to analyse quantitative and qualitative variables (percent and means ± SD. Spearman's rho test was used to find the correlation between RI of renal vessels and allograft size. The Qui-square test was used to find an association between RI and echogenicity of the graft. Results Renal transplantation was common at the age of 20 to 50 years. The mean Doppler index of the renal artery was 0.68±0.11 in renal allografts. Renal transplantation was common in professionals and homemakers (30.2 per cent and 20.93 per cent respectively. Hypertension and diabetes were the most common causes (44.1 per cent and 18.6 per cent. A significant correlation was found between RI and allograft size (p-value=0.012. There was no statistical association between RI and echogenicity of allograft (pvalue=0.106. Conclusion The Doppler resistive index is significantly correlated with allograft size and had no association with echogenicity. Patients with enlarged allograft had raised resistive indices. The study recommended that Duplex ultrasound should be used in the initial assessment and follow-up of renal transplant.

Time interval between maternal electrocardiogram and venous Doppler waves in normal pregnancy and preeclampsia: a pilot study.

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Tomsin, K; Mesens, T; Molenberghs, G; Peeters, L; Gyselaers, W

2012-12-01

To evaluate the time interval between maternal electrocardiogram (ECG) and venous Doppler waves at different stages of uncomplicated pregnancy (UP) and in preeclampsia (PE). Cross-sectional pilot study in 40 uncomplicated singleton pregnancies, categorized in four groups of ten according to gestational age: 10 - 14 weeks (UP1), 18 - 23 weeks (UP2), 28 - 33 weeks (UP3) and ≥ 37 weeks (UP4) of gestation. A fifth group of ten women with PE was also included. A Doppler flow examination at the level of renal interlobar veins (RIV) and hepatic veins (HV) was performed according to a standard protocol, in association with a maternal ECG. The time interval between the ECG P-wave and the corresponding A-deflection of the venous Doppler waves was measured (PA), and expressed relative to the duration of the cardiac cycle (RR), and labeled PA/RR. In hepatic veins, the PA/RR is longer in UP 4 than in UP 1 (0.48 ± 0.15 versus 0.29 ± 0.09, p ≤ 0.001). When all UP groups were compared, the PA/RR increased gradually with gestational age. In PE, the HV PA/RR is shorter than in UP 3 (0.25 ± 0.09 versus 0.42 ± 0.14, p advanced gestational stages are consistent with known features of maternal cardiovascular adaptation. Shorter values in preeclampsia are consistent with maternal cardiovascular maladaptation mechanisms. Our pilot study invites more research of the relevance of the time interval between maternal ECG and venous Doppler waves as a new parameter for studying the gestational cardiovascular (patho)physiology of the maternal venous compartment by duplex sonography. © Georg Thieme Verlag KG Stuttgart · New York.

Middle cerebral artery vasospasm: transcranial color-coded duplex sonography versus conventional nonimaging transcranial Doppler sonography.

Science.gov (United States)

Swiat, Maciej; Weigele, John; Hurst, Robert W; Kasner, Scott E; Pawlak, Mikolaj; Arkuszewski, Michal; Al-Okaili, Riyadh N; Swiercz, Miroslaw; Ustymowicz, Andrzej; Opala, Grzegorz; Melhem, Elias R; Krejza, Jaroslaw

2009-03-01

To prospectively compare accuracies of transcranial color-coded duplex sonography (TCCS) and transcranial Doppler sonography (TCD) in the diagnosis of middle cerebral artery (MCA) vasospasm. Prospective blinded head-to-head comparison TCD and TCCS methods using digital subtraction angiography (DSA) as the reference standard. Department of Radiology in a tertiary university health center in a metropolitan area. Eighty-one consecutive patients (mean age, 53.9 +/- 13.9 years; 48 women). The indication for DSA was subarachnoid hemorrhage in 71 patients (87.6%), stroke or transient ischemic attack in five patients (6.2%), and other reasons in five patients (6.2%). The MCA was graded as normal, narrowed 50% using DSA. The accuracy of ultrasound methods was estimated by total area (Az) under receiver operator characteristic curve. To compare sensitivities of ultrasound methods, McNemar's test was used with mean velocity thresholds of 120 cm/sec for the detection of less advanced, and 200 cm/sec for the more advanced MCA narrowing. Angiographic MCA narrowing 50% in 10 of 135 arteries. Accuracy of TCCS was insignificantly higher than that of TCD in the detection of 50% narrowing, total Az for mean velocity being 0.83 +/- 0.05, 0.77 +/- 0.05, and 0.95 +/- 0.02, 0.86 +/- 0.08, respectively. Sensitivity of TCCS at commonly used threshold of 120 cm/sec for less advanced MCA spasm was significantly better than that of TCD at similar specificity, 55% vs. 39%, p = 0.038, whereas at a threshold of 200 cm/sec used for more advanced spasm, sensitivities and specificities of both methods were not different. The accuracy of TCCS and TCD is similar, but TCCS is more sensitive than TCD in the detection of MCA spasm. Sensitivity of both techniques in the detection of mild and more advanced spasm using 120 cm/sec and 200 cm/sec thresholds, respectively, is poor; however, a larger sample is required to increase precision of our sensitivity estimates.

Transcranial Doppler sonography as diagnostic method

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Jasminka Đelilović-Vranić

2002-02-01

Full Text Available Having in mind the fact that cerebrovascular disease (CVB takes today in medicine, in spite of diagnostic and therapeutic modernisation, the third place of mortality causes in the world (behind cordial and malignant diseases, but in front of depressions, and the second place of invalidity cause (right after trauma as well as the second place of dementia cause (after Alzheimer disease, it urges primary prophylaxis. Developing countries, but before all countries of East and Middle Europe, where is our country, are highly risked areas where CV disease has trend of incidence and total frequency increase. In the neighbouring Croatia today CV disease is at the first place of mortality causes. In the world today 5 million people annually suffer CV disease, in Europe about 700.000, but frequency of suffering on Balkan is about 5 prom. Age of CV disease effecting unfortunately moved towards young age, and today 49% of effected by CV disease are of 46 to 59 years of age. Early detection and treatment of risk factors (before hypertension, smoking, diabetes mellitus, hyperlipidaemia, stress and physical non-activities are the first aspect of CV disease prophylaxis. Together with this aspect of primary prophylaxis is early detection of complications of mentioned risk factors on the walls of blood vessels, before all changing in sense of arteriosclerosis, with consequence of disorder of cerebral haemodynamics. With that objective - verification of circulator and total haemodynamic disorders, there is obvious disclose of non-invasive diagnostic methods, and one of them is Transcranial Doppler Sonography(TCD. TCD is method comfortable for patient, reliable and rather precise, dynamic, and can be repeated several times, without side effects and in comparison with others rather cheap.

Contribution of spiral artery blood flow changes assessed by transvaginal color Doppler sonography for predicting endometrial pathologies

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Suna Kabil Kucur

2013-01-01

Full Text Available ive: To investigate the diagnostic value of blood flow measurements in spiral artery by transvaginal color Doppler sonography (CDS in predicting endometrial pathologies.Methods: Ninety-seven patients presenting with abnormal uterine bleeding and requiring endometrial assessment were included in this prospective observational study. Endometrial thickness, structure and echogenicity were recorded. Pulsatility index (PI and resistive index (RI of the spiral artery were measured by transvaginal CDS. Endometrial sampling was performed for all subjects. Sonographic and hystopathologic findings were compared.Results: The histopathological diagnoses were as follows; 39 cases (40.2% endometrial polyp, 9 cases (9.3% endometrial hyperplasia, 10 cases (10.3 submucous myoma, 7 cases (7.2% endometrium cancer, and 32 cases (33% nonspecific findings. The spiral artery PI in endometrium cancer group was highly significantly lower than other groups (p<0.01. The spiral artery RI was also significantly lower in the patients with malignant histology (p<0.05. Conclusion: Endometrial pathologies are associated significantly with endometrial spiral artery Doppler changes.Key words: Spiral artery, Doppler ultrasonography, endometrium

Significance of the determination of doppler sonography haemodynamic indices for the assessment of distal perfusion in patients with critical ischemia of lower limbs

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Čizmić Milica

2006-01-01

Full Text Available Background/Aim: The perfusion of tissue, especially the muscles of the lower limbs (LL, implies the blood flow that carries enough nutrition, energy materials and oxygen. The aim of this study was to determine whether the decreased Doppler sonography parameters, resistance index (RI, and pulsatility index (PI were significant as indicators of irreversible ischemia of LL. Methods. In 40 patients (mean age 66±14.9 years, 21% women and 79% men with the signs of critical ischemia of LL, Lariche-Fontaine class III and IV, we performed contrast angiography of the LL arteries, and perfusion scintigraphy of LL using, thallium-201, while we performed Doppler sonography to determine resistance index (RI, as well as pulsatility index (PI. After that, all the patients were treated with vasodilatation using Bergmann's solution within a 10-day period. Following that, all the patients underwent the determination of haemodynamic indices RI and PI applying the methods of Doppler sonography. The obtained values of RI and PI indices revealed no clinical recovery which suggested the irreversibility of critical ischemia (unsuccessful therapy in 100% of the patients, and clinical recovery which suggested the reversibility of the disease (unsuccessful therapy in 80% of the patients. Results. The obtained values of PI = 0-0.3 and RI = 0-0.25 for the examined LL arteries were the indicators of irreversible ischemia. A significant correlation between the values of RI in the distal parts of a. tibialis anterior and posterior was proved, as well as between the decreased perfusion of LL determined by tallium-201 (p < 0.05, r = 0.43, and a tibialis anterior (p = 0.05, r = 0.38. There was, however, no statistically significant correlation between the angiographic values and perfusion scintigraphy of LL. Conclusion. The obtained values of haemodynamic RI and PI indices should be a novel approach for introducing a new criteria for the assessment of reversible and irreversible

Investigating language lateralization during phonological and semantic fluency tasks using functional transcranial Doppler sonography

Science.gov (United States)

Gutierrez-Sigut, Eva; Payne, Heather; MacSweeney, Mairéad

2015-01-01

Although there is consensus that the left hemisphere plays a critical role in language processing, some questions remain. Here we examine the influence of overt versus covert speech production on lateralization, the relationship between lateralization and behavioural measures of language performance and the strength of lateralization across the subcomponents of language. The present study used functional transcranial Doppler sonography (fTCD) to investigate lateralization of phonological and semantic fluency during both overt and covert word generation in right-handed adults. The laterality index (LI) was left lateralized in all conditions, and there was no difference in the strength of LI between overt and covert speech. This supports the validity of using overt speech in fTCD studies, another benefit of which is a reliable measure of speech production. PMID:24875468

Corpus luteum blood flow in normal and abnormal early pregnancy: evaluation and analysis with transvaginal color and pulsed doppler sonography

International Nuclear Information System (INIS)

Tang Xiaoyi; Lin Meifang; Zheng Meirong; Liang Xiaoxian; Liu Jianfeng

2005-01-01

Objective: Detecting and assessment the corpus luteum blood flow in normal and abnormal early pregnancy. Methods: Using transvaginal color and pulse Doppler sonography, we detected 215 pregnant women including 150 normal intrauterine pregnancies, 25 abortion, 29 ectopic pregnancies, and then recorded corpus luteum blood flow feature and the blood flow indexes (Vmax, RI and PI). Results: 1) Corpus luteum was successfully identified in 148 cases out of 150 of normal early pregnancies, 25 cases out of 26 of threatened abortion; 22 cases out of 29 of ectopic pregnancy. 2) Three groups shared the same feature of Color Doppler imaging: a circumferential rim around the entire corpus luteum. 3) The flow index revealed mean PVS, RI and PI had no statistical difference in normal and abnormal early pregnancy; The mean PVS was lower in ectopic pregnancy than in normal pregnancy (P<0.05), while PI and PR had no characteristic in ectopic pregnancy group compared with the indexes obtained in normal pregnancy group. Conclusion: The corpus luteum can be precisely identified in most pregnancy using transvaginal color Doppler and manifests a characterized rim Doppler imaging. PVS may help in differentiating the ectopic pregnancy from normal early pregnancy. (authors)

Angle-corrected imaging transcranial doppler sonography versus imaging and nonimaging transcranial doppler sonography in children with sickle cell disease.

Science.gov (United States)

Krejza, J; Rudzinski, W; Pawlak, M A; Tomaszewski, M; Ichord, R; Kwiatkowski, J; Gor, D; Melhem, E R

2007-09-01

Nonimaging transcranial Doppler sonography (TCD) and imaging TCD (TCDI) are used for determination of the risk of stroke in children with sickle cell disease (SCD). The purpose was to compare angle-corrected, uncorrected TCDI, and TCD blood flow velocities in children with SCD. A total of 37 children (mean age, 7.8 +/- 3.0 years) without intracranial arterial narrowing determined with MR angiography, were studied with use of TCD and TCDI at the same session. Depth of insonation and TCDI mean velocities with and without correction for the angle of insonation in the terminal internal carotid artery (ICA) and middle (MCA), anterior (ACA), and posterior (PCA) cerebral arteries were compared with TCD velocities with use of a paired t test. Two arteries were not found on TCDI compared with 15 not found on TCD. Average angle of insonation in the MCA, ACA, ICA, and PCA was 31 degrees , 44 degrees , 25 degrees , and 29 degrees , respectively. TCDI and TCD mean depth of insonation for all arteries did not differ significantly; however, individual differences varied substantially. TCDI velocities were significantly lower than TCD velocities, respectively, for the right and left sides (mean +/- SD): MCA, 106 +/- 22 cm/s and 111 +/- 33 cm/s versus 130 +/- 19 cm/s and 134 +/- 26 cm/s; ICA, 90 +/- 14 cm/s and 98 +/- 27 cm/s versus 117 +/- 18 cm/s and 119 +/- 23 cm/s; ACA, 74 +/- 24 cm/s and 88 +/- 25 cm/s versus 105 +/- 23 cm/s and 105 +/- 31 cm/s; and PCA, 84 +/- 27 cm/s and 82 +/- 21 cm/s versus 95 +/- 23 cm/s and 94 +/- 20 cm/s. TCD and angle-corrected TCDI velocities were not statistically different except for higher angle-corrected TCDI values in the left ACA and right PCA. TCD velocities are significantly higher than TCDI velocities but are not different from the angle-corrected TCDI velocities. TCDI identifies the major intracranial arteries more effectively than TCD.

Transabdominal bowl sonography

DEFF Research Database (Denmark)

Wilkens, Rune; Strandberg, Charlotte

2014-01-01

This focused review describes the current use and future perspectives regarding transabdominal bowel sonography (TABS). The technique for B-mode and Doppler is described and the use of ultrasound contrast and elastography is discussed. Pathology and subsequent imaging findings are focused on appe...... on appendicitis, diverticulitis, inflammatory bowel diseases and within paediatric conditions along with other common intestinal pathology. In conclusion we find that TABS is a fast, efficient, low-cost and non-ionization imaging technique without any patient discomfort....

Patient-exposure data for doppler ultrasound

International Nuclear Information System (INIS)

Stewart, H.F.; Silvis, P.X.; Smith, S.W.

1986-01-01

In recent years ultrasound imaging and Doppler blood flow measurements have become important tools for use in diagnostic medicine. Commercial pulse-echo imaging equipment was first introduced into commerce in 1963. The first commercial continuous wave Doppler unit was introduced to the marketplace in 1966. As equipment improved and applications developed, the industry experienced rapid growth in the 1970s. One of the more recent growth areas in the application of diagnostic ultrasound has been the use of pulsed Doppler equipment for cardiac applications. Prior to 1976, some continuous wave Doppler ultrasound was used for cardiovascular diagnosis. However, only a single manufacturer marketed a pulsed Doppler clinical instrument for cardiac or peripheral vascular diagnosis. Currently, many continuous wave and pulsed Doppler instruments are commercially available for both peripheral vascular and cardiac diagnosis. This chapter (1) briefly reviews current safety guidelines, regulations, and recommendations for diagnostic ultrasound; (2) discusses the patient-exposure intensities associated with Doppler ultrasound medical equipment and compare these levels of exposure with intensities from other medical ultrasound devices; and (3) considers some of the current information as it relates to the safety of diagnostic ultrasound

Comparison of findings of spontaneous splenorenal shunt in color Doppler sonography with multislice CT scan (64 slices) in liver transplant candidates

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Bagheri, Mohammadhadi, E-mail: Bagherimh@gmail.com [Department of Radiology, Shiraz University of Medical Sciences, Namazi Hospital, Shiraz (Iran, Islamic Republic of); Hajati, Azadeh, E-mail: azadeh.hajati@gmail.com [Department of Radiology, Shiraz University of Medical Sciences, Namazi Hospital, Shiraz (Iran, Islamic Republic of); Hosseini, Mohammadkazem, E-mail: hosseiniaslm@sums.ac.ir [Department of Radiology, Shiraz University of Medical Sciences, Namazi Hospital, Shiraz (Iran, Islamic Republic of); Ostad, Seyed Pouria, E-mail: Pouria.Ostad@gmail.com [Department of Radiology, Shiraz University of Medical Sciences, Namazi Hospital, Shiraz (Iran, Islamic Republic of)

2012-09-15

Background: Liver transplantation is the only definite treatment for end stage liver disease and it has high costs for the medical system so decreasing its complication and increasing its effectiveness is crucial. One of the factors that affect liver transplantation is the presence of spontaneous splenorenal shunt. Its diagnosis is mainly overlooked in pre-liver transplant patients. Main modality for its diagnosis is multislice CT scan however this is more expensive than sonography. Also, it exposes the patients to ionizing radiation. Considering the advantages of color Doppler ultrasound, studies to determine the sensitivity and specificity for detection of spontaneous splenorenal shunt is essential. Materials and methods: In our study 70 cirrhotic patients who were referred by liver transplant surgeons for evaluation of abdomen by CT and sonograhy were assessed for presence of spontaneous splenorenal shunt, left adrenal varix and left renal vein diameter and velocity and sensitivity and specificity of both modalities were checked. Patients in whom left renal vein could not evaluated by sonography and patients with splenectomy and nutcracker syndrome were excluded. Results: In the point of 10 mm diameter of left renal vein in CT scan there was 78.6% sensitivity and 67.9% specificity for the presence of spontaneous splenorenal shunt. Left adrenal varix in CT had sensitivity of 71.4%, specificity of 100%, and positive predictive value of 100% and negative predictive value of 70% and varix below spleen in CT had sensitivity of 54.8%, specificity of 96.4%, and positive predictive value of 95.8% and negative predictive value of 58.7% for the presence of spontaneous splenorenal shunt. In the point of 8 mm diameter of left renal vein in sonography there was 66.7% sensitivity and 85.7% specificity for the presence of spontaneous splenorenal shunt. For the velocity of more than 35 cm/s of left renal vein in sonography there was 61.9% sensitivity and 82.1% specificity for

Childhood acute pyelonephritis: comparison of power Doppler sonography and Tc-DMSA scintigraphy

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Stogianni, Aggeliki; Oikonomou, Ippoliti; Dimitriadis, Athanasios [Aristotle University of Thessaloniki, Department of Radiology, AHEPA Hospital, Thessaloniki (Greece); Nikolopoulos, Panagiotis [424 Army Hospital, Department of Radiology, Thessaloniki (Greece); Gatzola, Magdalini [Aristotle University of Thessaloniki, 2nd Paediatric Clinic, AHEPA Hospital, Thessaloniki (Greece); Balaris, Vassilios [Aristotle University of Thessaloniki, Department of Nuclear Medicine, AHEPA Hospital, Thessaloniki (Greece); Farmakiotis, Dimitrios [Infectious Diseases Hospital of Thessaloniki, Department of Medicine, Thessaloniki (Greece)

2007-07-15

Tc 99m DMSA scintigraphy is regarded as the gold standard for the detection and localization of acute pyelonephritis (APN) in children. Power Doppler sonography (PD US) is a radiation-free and cost-effective technique that could be useful in the diagnosis of APN in children. To compare the predictive value of PD US with DMSA scintigraphy in the diagnosis of APN in children. A total of 74 neonates and children with clinical findings consistent with possible upper urinary tract infection were evaluated with PD US and DMSA scintigraphy. Children with anatomic (grey-scale) abnormalities were excluded. A total of 147 kidneys were examined within the first 48 h after the onset of symptoms. Each kidney was divided into three zones (upper, middle, and lower third). APN was diagnosed by PD US in 46 kidneys. Sensitivity and specificity for detecting APN using DMSA scintigraphy as the reference standard were 73.8% and 85.7%, respectively. There was good agreement between PD US and DMSA scintigraphy in the localization of lesions. In clinically suspected APN, PD US has acceptable specificity and sensitivity, if performed within the first 48 h and could be helpful in neonates and children under 3 months of age in whom the use of scintigraphy is generally discouraged. (orig.)

Color/power Doppler transrectal US in prostate cancer: Correlation with Gleason score

International Nuclear Information System (INIS)

Kim, Hyo Cheol; Kim, Seung Hyup; Moon, Min Hoan; Park, Byung Kwan; Kim, Keon Ha; Choi, Hyuck Jae; Yoon, Chang Jin

2002-01-01

To evaluate the relationship between hypervascularity on color/power Doppler transrectal ultrasonography and the Gleason score of corresponding biopsied specimen in patients with prostatic cancer. From July 1998 to March 2002, one hundred fifty seven patients with pathologically proven prostate cancer at this institution were included, and all of them underwent transrectal ultrasonographic examination. Initially, ultrasonographic findings and pathologic data of 129 patients were retrospectively reviewed and excluded 28 patients whose sonographic images were either unavailable or inconclusive. The presence of hypoechoic lesion on transrectal sonography and hypervascularity on color/power Doppler sonography in the peripheral zone of the prostate was first evaluated, and these sonographic findings and Gleason score of the corresponding biopsied specimen were then compared. Statistical analysis was done by Student t-test using SPSS package. Among one hundred twenty nine patients, ninety four patients had a hypoechoic lesion on gray scale sonography while sixty one showed a hypervascular lesion on color/power Doppler sonography. Fifty seven of 61 patients (93.4%) had hypoechoic lesion on gray scale sonography. The mean Gleason score of patients with hypervascular lesion was 7.9 ± 0.98 whereas that of the patients without hypervascular lesion, 6.9 ± 1.22, showing a statistically significant difference (p<0.01). Prostate cancer with hypervascularity on transrectal sonography appears to have a higher Gleason score on pathologic examination than that without hypervascularity.

Hepatic vein flow pattern in children: assesment with Doppler sonography

International Nuclear Information System (INIS)

Ahmetoglu, Ali; Kosucu, Polat; Arikan, Elif; Dinc, Hasan; Resit Guemele, Halit

2005-01-01

Background: Aim of this study is to establish normal hepatic vein flow pattern and effect of age, sex, activity and feeding status on the hepatic flow pattern in normal Turkish children less than 15 years of ages and also to compare our values with the previously reported studies. Method: Hepatic vein flow patterns were evaluated in 150 children (83 male, 67 female) without any cardiac, pulmonary and liver disease by using Doppler sonography. Blood flow patterns were compared with age, sex, activity, and feeding status of the children. Results: Only 44% of the children had triphasic flow pattern in all hepatic veins. Monophasic flow pattern was the most common flow pattern in children less then 1 year of age. Triphasic flow pattern increase after 1 year of age. Although most of the children older than 1 year of age had triphasic flow pattern, there is some variation in the flow patterns of the hepatic veins in the same subject. Triphasic hepatic flow pattern is most commonly seen in the left hepatic vein and least commonly seen in the right hepatic vein. There was no significant difference between male and girl, children who were agitated or calm and fasting or not fasting in respect to triphasic flow pattern. Conclusion: Liver stiffening is not only the reason for abnormal hepatic flow pattern and some other physiologic factors may also lead to mono and/or diphasic flow pattern in the children. Absence of triphasic flow pattern must not be accepted as a liver pathology in children especially younger than 1 year of age

Does ultrasound contrast agent improve the diagnostic value of colour and power Doppler sonography in superficial lymph node enlargement?

International Nuclear Information System (INIS)

Schulte-Altedorneburg, Gernot; Demharter, Johannes; Linne, Renate; Droste, Dirk W.; Bohndorf, Klaus; Buecklein, Wolfgang

2003-01-01

Objective: to analyse whether ultrasound contrast agent (UCA) improves the diagnostic accuracy to differentiate between benign and malignant superficial lymph node enlargement by using colour-coded duplex sonography (CCDS) and power Doppler (PD). Methods: 32 patients with suspected malignant superficial lymph node enlargement prospectively underwent standardised ultrasound examinations using B-mode sonography and native and contrast-enhanced CCDS and PD immediately before biopsy. Solbiati-Index (longitudinal-transverse diameter ratio) and intranodal flow patterns by using different vascularisation types were assessed. Histological and sonographical findings were correlated. Results: 27 malignant and 5 benign lymph nodes were found. Solbiati-Index was lower in malignant lymph nodes than in benign nodes (mean 1.5 vs. 2.4, P<0.045). More intranodal flow patterns could be detected after UCA (53 vs. 43) but the number of correctly identified malignant nodes decreased after UCA (26 vs. 24) and the number of correctly identified benign nodes remained constant compared with native CCDS and PD. In 31% of the colour-mode studies, PD was considered to visualise more clearly intranodal vascular flow patterns than CCDS. Conclusion: despite depicting more intranodal vascular patterns, the use of an ultrasound contrast agent seems not to improve the diagnostic value of CCDS and PD compared with native colour-mode studies in superficial lymph node enlargement

Aortic coarctation diagnosed by renal Doppler flow patterns in a hypertensive young patient: a case report

International Nuclear Information System (INIS)

Sari, S.; Kara, K.; Verim, S.

2012-01-01

Full text: Introduction: Aortic coarctation is a congenital malformation, which can cause systemic hypertension and subsequent complications, and causes of secondary hypertension, affecting in differential pressures in the upper and lower extremities. Because hypertension is caused by aortic coarctation, tends to be resistant to medical therapy, early recognition and surgical rectification are important. Objectives and tasks: In this article, we aimed to point out that renal Doppler sonography is a beneficial and frequently used to evaluate secondary hypertension, if there are bilateral tardus-parvus wave patterns are detected. Thus, bilateral renal artery stenosis, aortic stenosis, and coarctation should be considered in this condition. Materials and methods: A 23-year-old male who has six-month history of hypertension. He was referred by a cardiologist for investigation of his secondary hypertension. There was an ascending aortic dilatation, left ventricular hypertrophy in his echocardiography. Results: The patient's blood pressure was measured as 160/90 mm Hg in his both arms. Renal Doppler sonography was performed to identify the potential cause of secondary hypertension, specifically renal artery stenosis, after tardus-parvus pulse waves were noted in both renal intralobar-arteries. Aortic coarctation is suspected and then a chest computed tomography (CT) was performed to evaluate supra-diaphragmatic vessel abnormalities. The CT exposed a stenotic lesion in the isthmus of the aorta. The patient was transferred to cardiovascular surgery department for treatment. Conclusion: Careful physical examination should be performed in all hypertensive patients. If bilateral tardus-parvus wave pattern are seen in patients who has been referred for Doppler evaluation on suspicion of renovascular hypertension, aortic coarctation should be considered as differential diagnosis

Pseudoaneurysm of the posterior circumflex humeral artery diagnosed by sonography

DEFF Research Database (Denmark)

Damgaard, Bodil; Court-Payen, Michel; Larsen, Lone

2009-01-01

with a painless, nonpulsatile mass in the posterior shoulder region and was suspected of a malignant soft-tissue tumor. Sonography, including power Doppler imaging, demonstrated a pseudoaneurysm, with the intralesional blood-filled cavity developed from the posterior circumflex humeral artery. The diagnosis...

New developments in imaging: Sonography, cine-CT, MRI

International Nuclear Information System (INIS)

Otto, R.J.; Higgins, C.B.

1987-01-01

The book can be conveniently subdivided into three sections: the first on magnetic resonance imaging the second on cine-computed tomography and the third on advances in ultrasound (US). The MR imaging section includes two chapters: the first on indications for MR in abdominal disease (a cookbook layout of indications for MR imaging versus CT) and the second on MR imaging of the heart. There are also chapters on MR imaging and US in the pelvis, contrast agent principles, and a chapter on imaging renal tumors. The third section, on US, contains chapters on the liver and gastrointenstinal disease, interventional US sonography during neurosurgery, state-of-the-art echocardiography. Doppler flow imaging, contrast media for sonography, endometrial sonography, and high-resolution US in the first trimester. The final chapter is presented as a scientific paper rather than as a chapter in a book and has no illustrations

Transesophageal color Doppler evaluation of obstructive lesions using the new "Quasar" technology.

Science.gov (United States)

Fan, P; Nanda, N C; Gatewood, R P; Cape, E G; Yoganathan, A P

1995-01-01

Due to the unavoidable problem of aliasing, color flow signals from high blood flow velocities cannot be measured directly by conventional color Doppler. A new technology termed Quantitative Un-Aliased Speed Algorithm Recognition (Quasar) has been developed to overcome this limitation. Employing this technology, we used transesophageal color Doppler echocardiography to investigate whether the velocities detected by the Quasar would correlate with those obtained by continuous-wave Doppler both in vitro and in vivo. In the in vitro study, a 5.0 MHz transesophageal transducer of a Kontron Sigma 44 color Doppler flow system was used. Fourteen different peak velocities calculated and recorded by color Doppler-guided continuous-wave Doppler were randomly selected. In the clinical study, intraoperative transesophageal echocardiography was performed using the same transducer 18 adults (13 aortic valve stenosis, 2 aortic and 2 mitral stenosis, 2 hypertrophic obstructive cardiomyopathy and 1 mitral valve stenosis). Following each continuous-wave Doppler measurement, the Quasar was activated, and a small Quasar marker was placed in the brightest area of the color flow jet to obtain the maximum mean velocity readout. The maximum mean velocities measured by Quasar closely correlated with maximum peak velocities obtained by color flow guided continuous-wave Doppler in both in vitro (0.53 to 1.65 m/s, r = 0.99) and in vivo studies (1.50 to 6.01 m/s, r = 0.97). We conclude that the new Quasar technology can accurately measure high blood flow velocities during transesophageal color Doppler echocardiography. This technique has the potential of obviating the need for continuous-wave Doppler.

Budd-chiari syndrome by membranous obstruction of inferior vena cava: comparison of sonography and computed tomography

International Nuclear Information System (INIS)

Lee, Dong Ho; Lim, Jae Hoon; Ko, Young Tae; Yoon, Yup; Lim, Joo Won

1992-01-01

Membranous obstruction of the hepatic inferior vena cava (MOVC) is one of the common causes of Budd-Chiari syndrome. The aim of this study is to ascertain and compare the characteristic sonographic and CT findings of Budd-Chiari syndrome caused by MOVC. We studied 10 patients of Budd-Chiari syndrome caused by MOVC thorough sonography and CT. MOVC was confirmed by operation and/or inferior vena cavography. The cases included 9 men and one woman. With sonography, IVC obstruction was diagnosed in 9 cases. The cause of IVC obstruction was web in 5 cases and fibrous cord in 3 cases. The cause was unspecified in one case. Obliteration of the hepatic veins and intrahepatic collateral vessels were delineated in 9 cases. With color doppler sonography, the directions of blood flow of the hepatic veins through the intervenous communication were fairly well demonstrated in all 5 cases. With CT, IVC obstruction was diagnosed in 7 cases. The obliteration of the hepatic segment of the IVC were segmental in 6 cases and diffuse in one case. CT demonstrated communicating vessels between the hepatic veins in 3 cases. Furthermore, systemic collateral vessels (azygos and hemiazygos veins, veins along the abdominal wall, and internal mammary veins) were demonstrated in all cases. Liver cirrhosis was combined in all cases and hepatoma developed in 4 cases. Sonography is useful to detect the MOVC and to demonstrate hepatic venous obstruction and intrahepatic collateral vessels. Color doppler sonography is easily performed to show the direction of the blood flow through interconnecting vessels. CT shows the obliterated segment of the IVC clearly and multiple prominent systemic collaterals. In conclusion, Budd-Chiari syndrome caused by MOVC is accurately diagnosed by combined color doppler sonography and CT

Detection and volume estimation of embolic air in the middle cerebral artery using transcranial Doppler sonography.

Science.gov (United States)

Bunegin, L; Wahl, D; Albin, M S

1994-03-01

Cerebral embolism has been implicated in the development of cognitive and neurological deficits following bypass surgery. This study proposes methodology for estimating cerebral air embolus volume using transcranial Doppler sonography. Transcranial Doppler audio signals of air bubbles in the middle cerebral artery obtained from in vivo experiments were subjected to a fast-Fourier transform analysis. Audio segments when no air was present as well as artifact resulting from electrocautery and sensor movement were also subjected to fast-Fourier transform analysis. Spectra were compared, and frequency and power differences were noted and used for development of audio band-pass filters for isolation of frequencies associated with air emboli. In a bench model of the middle cerebral artery circulation, repetitive injections of various air volumes between 0.5 and 500 microL were made. Transcranial Doppler audio output was band-pass filtered, acquired digitally, then subjected to a fast-Fourier transform power spectrum analysis and power spectrum integration. A linear least-squares correlation was performed on the data. Fast-Fourier transform analysis of audio segments indicated that frequencies between 250 and 500 Hz are consistently dominant in the spectrum when air emboli are present. Background frequencies appear to be below 240 Hz, and artifact resulting from sensor movement and electrocautery appears to be below 300 Hz. Data from the middle cerebral artery model filtered through a 307- to 450-Hz band-pass filter yielded a linear relation between emboli volume and the integrated value of the power spectrum near 40 microL. Detection of emboli less than 0.5 microL was inconsistent, and embolus volumes greater than 40 microL were indistinguishable from one another. The preliminary technique described in this study may represent a starting point from which automated detection and volume estimation of cerebral emboli might be approached.

Sub-Doppler spectroscopy

International Nuclear Information System (INIS)

Hansch, T.W.

1983-01-01

This chapter examines Doppler-free saturation spectroscopy, tunable cw sources, and Doppler-free two-photon spectroscopy. Discusses saturation spectroscopy; continuous wave saturation spectroscopy in the ultraviolet; and two-photon spectroscopy of atomic hydrogen 1S-2S. Focuses on Doppler-free laser spectroscopy of gaseous samples. Explains that in saturation spectroscopy, a monochromatic laser beam ''labels'' a group of atoms within a narrow range of axial velocities through excitation or optical pumping, and a Doppler-free spectrum of these selected atoms is observed with a second, counterpropagating beam. Notes that in two-photon spectroscopy it is possible to record Doppler-free spectra without any need for velocity selection by excitation with two counterpropagating laser beams whose first order Doppler shifts cancel

Comparative analysis of pulsed doppler ultrasonography of portal vein vs indirect photography

International Nuclear Information System (INIS)

Chang, Jae Chun; Kwon, Huck Po; Hwang, Mi Soo; Kim, Sun Youn; Park, Bok Hwan; Lee, Hyun Ju; Kim, Hong Jin

1990-01-01

There are some limitation of interpretation in indirect photography via superior mesenteric artery. In order to supplement and predict indirect photography, we compared indirect photographic findings with pulsed doppler flowmetry in 38 hepatobiliary patients, and the results were as follow: 1. In case of normal main portal vein(MPV) filling, Pulsed Doppler always showed antegrade, continuous parabolic wave form and cases of abnormal MPV filling, showed unusual wave form and flow direction. 2. In normal filling case of proximal right portal vein, Pulsed Doppler almost showed normal continuous parabolic wave form but in normal filling cases of proximal left portal vein, occasionally showed undulating wave form. 3. In each side proximal portal vein abnormal filling case, we could observe abnormal doppler wave form and could obtain additional information using doppler wave form. 4. Mean portal flow velocity was significantly increased in higher photography grade(p=0.01) and congestion index was significantly decreased in higher photography grade(p=0.01). 5. We concluded that doppler ultrasonography could supplement incomplete indirect photography

Pulsed-wave transmitral Doppler do not diagnose moderate acute rejection after heart transplantation

NARCIS (Netherlands)

Mannaerts, H. F.; Simoons, M. L.; Balk, A. H.; Tijssen, J.; van der Borden, S. G.; Zondervan, P. E.; Mochtar, B.; Weimar, W.; Roelandt, J. R.

1993-01-01

The value of pulsed-wave transmitral Doppler for the diagnosis of moderate acute rejection was examined in a total of 347 Doppler recordings obtained in 32 consecutive cardiac allograft recipients. Serial Doppler examinations (median, 11 per patient; range, 1 to 23) were performed simultaneously

PULSED-WAVE TRANSMITRAL DOPPLER DO NOT DIAGNOSE MODERATE ACUTE REJECTION AFTER HEART-TRANSPLANTATION

NARCIS (Netherlands)

MANNAERTS, HF; SIMOONS, ML; BALK, AH; TIJSSEN, J; VANDERBORDEN, SG; ZONDERVAN, PE; MOCHTAR, B; WEIMAR, W; ROELANDT, [No Value

1993-01-01

The value of pulsed-wave transmitral Doppler for the diagnosis of moderate acute rejection was examined in a total of 347 Doppler recordings obtained in 32 consecutive cardiac allograft recipients. Serial Doppler examinations (median, 11 per patient; range, 1 to 23) were performed simultaneously

Right hemispheric language dominance in a right-handed male with a right frontal tumor shown by functional transcranial Doppler sonography.

Science.gov (United States)

Haag, A; Preibisch, C; Sure, U; Knake, S; Heinze, S; Krakow, K; Rosenow, F; Hamer, H M

2006-02-01

A 38-year-old, right-handed man with late-onset right frontal epilepsy due to a ganglioglioma and atypical right hemispheric language dominance is described. Language dominance was investigated with functional transcranial Doppler sonography (fTCD), and language localization with functional magnetic resonance imaging (fMRI). During a word generation task, fTCD showed atypical right hemispheric language dominance, which was confirmed by fMRI using a semantic word comparison and a word stem completion task. This information helped to guide the resective procedure, which left the patient seizure-free and did not induce new deficits. Functional TCD appears to be a useful and reliable screening tool for determining hemispheric language dominance, even in patients with atypical language representation. Functional MRI may be used to confirm fTCD results and further localize eloquent cortex.

Doppler limited rotational transitions of OH and SH radicals measured by continuous-wave terahertz photomixing

Science.gov (United States)

Eliet, Sophie; Martin-Drumel, Marie-Aline; Guinet, Mickaël; Hindle, Francis; Mouret, Gaël; Bocquet, Robin; Cuisset, Arnaud

2011-12-01

A continuous-wave terahertz (CW-THz) source generated by photomixing has been employed to detect and quantify radicals produced in a cold plasma probing their spin-rotation transitions. Due to their dual interest for both atmospherists and astrophysicists, the hydroxyl OH and the mercapto SH radicals have been chosen. The photomixing technique which can access the largest range of THz frequencies of any known coherent source, allowed to resolve the Doppler-limited hyperfine transitions of OH in the 2.5 THz frequency region. Line profile analysis of the hyperfine components demonstrated that OH radicals have been detected in this region at a ppm level at a temperature close to 490 K. The hyperfine structure of SH has been resolved for the first time above 1 THz. Ten new frequency transitions have been measured in the 1.3-2.6 THz frequency range using the CW-THz synthesizer based on a frequency comb. With relative uncertainties better than 10 -7, the CW-THz frequencies measured in this study are now competitive with those measured by other instruments such as frequency multiplication chains or FT-FIR spectrometers and are now capable to improve the predictions of the complete high-resolution spectra of these radicals collected in the atmospheric and astrophysical spectroscopic databases. versioncorrigeeAC 2011-07-18 17:32 2011 Arnaud Cuisset.

Full-wave Simulation of Doppler Reflectometry in the Presence of Turbulence

Energy Technology Data Exchange (ETDEWEB)

Lechte, C. [Institut fur Plasmaforschung, Universitat Stuttgart, Stuttgart (Germany)

2011-07-01

Doppler reflectometry is a microwave plasma diagnostic well suited for density fluctuation measurement. A meaningful interpretation of Doppler reflectometry measurements necessitates the analysis of the wave propagation in the plasma using simulations methods. While the beam path can usually be reconstructed with beam tracing methods, the modeling of the scattering process demands the use of wave simulation codes. Furthermore, in the presence of strong density fluctuations, the response from the plasma is dominated by dispersion and multiple scattering, and hence becomes non-linear. IPF-FD3D is the finite difference time domain code used to investigate the dependence of the scattering efficiency on the various plasma conditions. It uses the full set of Maxwell equations and the electron equation of motion in a cold plasma. First results in slab geometry indicate a strong dependence of the scattering efficiency on the density gradient, the incident angle, and the wave polarisation. Further complications arise with the introduction of broadband turbulent fluctuations, where additional knowledge of the radial spectrum is necessary to reconstruct the full fluctuation spectrum from Doppler reflectometry measurements. This paper presents the reconstruction of the turbulent fluctuation spectrum from simulated Doppler reflectometry measurements in slab geometry. Two cases of analytical turbulence in slab geometry are presented where the fluctuation wavenumber spectrum was recovered. It is planned to extend these investigations to X mode polarization and to supplement actual fusion experiments

Effect of intertrochanteric osteotomy on the proximal femur of rabbits: assessment with power Doppler sonography and scintigraphy Efeito da osteotomia intertrocantérica no femur proximal de coelhos: avaliação com utra-sonografia power Doppler e cintilografia

Directory of Open Access Journals (Sweden)

Andrea S. Doria

2007-01-01

Full Text Available OBJECTIVE: In bone injury, repair results in local increased vascularity and bone marrow remodeling. Characterizing the vascular and metabolic imaging patterns of the proximal femur following an intertrochanteric osteotomy may help clinicians decide proper management of the patient. Our objective was to measure Doppler sonography and scintigraphy interval changes in the proximal femur following intertrochanteric osteotomy and compare imaging and histomorphometric measurements in the late post-operative stage (6 weeks after surgery in a rabbit model of bone injury. MATERIALS AND METHODS: Both hips of 12 adult rabbits were imaged with power Doppler sonography and scintigraphy prior to and after (7 days and 6 weeks unilateral osteotomy. Accuracy of the imaging methods was evaluated using hip operative status and histomorphometric results (vascular fractional area and number of vessels per area unit as reference standard measures. RESULTS: A significant difference in the mean number of pixels was noted between operated and non-operated femura in late post-operative power Doppler examinations (P=0.049. Although without reaching statistical significance, the AUC of Doppler measurements (AUC=0.99 was numerically greater than the AUC of scintigraphy measurements (AUC=0.857±0.099 (P=0.15 in differentiating proximal femura with regard to their fractional vascular areas in the late post-operative stage. In contrast, scintigraphy tended to perform better (AUC=0.984±0.022 than Doppler ultrasound (AUC=0.746±0.131 to demonstrate the vascularity intensity per area unit (P=0.07 in the late stage. CONCLUSION: Our results warrant further investigation to determine the value of different imaging modalities for assessment of pathologic changes following hip surgery. Power Doppler sonography demonstrated larger AUCs (representing higher accuracy for the discrimination of vascular fractional areas and scintigraphy, for discrimination of the number of vessels per

The efficiency of sonography in diagnosing volvulus in neonates with suspected intestinal malrotation.

Science.gov (United States)

Zhang, Wenhua; Sun, Hongjun; Luo, Fangqiong

2017-10-01

This study is to prospectively evaluate the efficiency of sonography for volvulus diagnosis in neonates with clinically suspected intestinal malrotation.A total of 83 patients with suspected intestinal malrotation who underwent detailed abdominal sonography and upper gastrointestinal contrast study were included. Malrotation was characterized by inversion of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) in sonographic examination. The "whirlpool sign" of Color Doppler Sonography was recognized as a characteristic for malrotation with volvulus. The degrees of rotation of the SMV winding around SMA were also detected by sonography. Surgery was performed in patients with sonography diagnosed malrotation.A total of 39 patients were sonographically diagnosed as malrotation which was subsequently confirmed by surgery. The sensitivity and positive predictive value of the sonographic diagnosis were both 100% (39/39). The sensitivity, specificity and accuracy of "whirlpool sign" for the detection of midgut volvulus were 95.2% (20/21), 88.9% (16/18), and 92.3% (36/39), respectively. Greater degrees of rotation (equal or greater than 720°) showed higher risk (odds ratio, 5.0; P volvulus may be used as a potential indicator for intestinal necrosis. In addition, sonography can exclude malrotation and may help the diagnosis of other diseases, such as annular pancreas and duodenal atresia.

Color doppler findings of gastric varices compared with findings on computed tomography

Energy Technology Data Exchange (ETDEWEB)

Sato, Takahiro; Yamazaki, Katsu; Toyota, Jouji; Karino, Yoshiyasu; Ohmura, Takumi; Suga, Toshihiro [Sapporo Kosei General Hospital (Japan)

2002-08-01

The aim of this study was to evaluate the hemodynamics of gastric varices. We evaluated the detection rates of gastric varices, inflowing vessels to gastric varices, and outflowing vessels from gastric varices in 24 patients with gastric varices, using color Doppler sonography, and compared these findings with computed tomography findings. Eighteen patients had F2-type varices and 6 had F3-type, classified according to the Japanese Research Society for Portal Hypertension. Fourteen patients had fundal varices, and 10 had cardiac and fundal varices. The detection rates of collateral veins using color Doppler sonography were as follows: gastric varices were detected in all 24 patients (100%); inflowing vessels, in 21 of the 24 patients (87.5%); and outflowing vessels, in 18 of the 24 patients (75.0%). The detection rates of collateral veins, using computed tomography, were: gastric varices were detected in all 24 patients (100%); inflowing vessels, in all 24 patients (100%); and outflowing vessles, in 21 of the 24 patients (87.5%). The color Doppler findings agreed perfectly with the computed tomography findings in 13 of the 24 patients (54.2%). Although color Doppler sonography is a useful, noninvasive modality for evaluating the hemodynamics of gastric varices, it falls short in visualizing the detailed hemodynamics of the inflowing and outflowing vessels of gastric varices in half of the patients when compared with computed tomography. (author)

Doppler Sonographic Evaluation of Venogenic Extremity Swellings ...

African Journals Online (AJOL)

2017-09-14

Sep 14, 2017 ... potentially lead to many complications including life-threatening pulmonary arterial thrombosis. Screening and confirmation ... and exclusion of acute lower extremity DVT. Duplex ultrasound is considered as the ... this study evaluates the role of Doppler sonography in the clinical management of suspected.

Prediction of cerebrovascular reserve by the MRI and doppler ultrasonography

Energy Technology Data Exchange (ETDEWEB)

Lee, Hui Joong; Kim, Yong Sun [Kyungpook National University Hospital, Daegu (Korea, Republic of)

2005-07-15

We investigated acute stroke patterns on diffusion weighted images and with doppler ultrasonography studies of ICA and MCA steno-occlusive diseases in order to predict the cerbrovascular reserve (CVR), as was measured by acetazolamide (ACZ)-challenged Tc-99m ECD brain perfusion SPECT. A retrospective analysis was performed of 76 patients who underwent MRI/MRA, ACZ-challenged Tc-99m ECD brain perfusion SPECT, and carotid and vertebral artery Doppler sonography. After dividing these patients into four groups-MCA and ICA ateno-occlusions, we analyzed the relationship between the CVR and topologic MR patterns and the flow volume, as was measured by Doppler sonography. The CVRs were preserved in 26 of 76 patients. The CVRs were impaired in those cases of occlusion that were detected on MRA and also by the pattern of the territorial involvement on the diffusion weighted image ({rho} < 0.05, x{sup 2} test). Yet in cases of preserved CVRs, the flow volume of the contralateral ICA, the anterior circulation, and the total cerebral flow volume were increased, as was checked by Doppler sonography ({rho} < 0.05, t-test). As calculated by logistic regression analysis, the accuracy for predicting the preserved CVR by using the statistically significant variables was 78%. We believe that the MRI-SPECT correlation study was helpful for understanding the hemodynamics and topographic patterns of ischemia in patients with ICA and MCA steno-occlusive disease, and that the flow volume measurement, which was done by using duplex US, was useful for predicting the CVR.

Detection of cerebrovascular disease in patients with sickle cell disease using transcranial Doppler sonography: correlation with MRI, MRA and conventional angiography

Energy Technology Data Exchange (ETDEWEB)

Verlhac, S. [Service de Radiologie, Centre Hospitalier Intercommunal, 94 - Creteil (France); Bernaudin, F. [Service de Pediatrie, Centre Hospitalier Intercommunal, 94 - Creteil (France); Tortrat, D. [Association Claude Bernard, 75 - Paris (France); Brugieres, P. [Service de Neuroradiologie, Hopital Henri Mondor, 94 - Creteil (France); Mage, K. [Service de Radiologie, Centre Hospitalier Intercommunal, 94 - Creteil (France); Gaston, A. [Service de Neuroradiologie, Hopital Henri Mondor, 94 - Creteil (France); Reinert, P. [Service de Pediatrie, Centre Hospitalier Intercommunal, 94 - Creteil (France)

1995-11-01

A prospective study of 58 patients with sickle cell disease (SCD) by transcranial Doppler sonography (TCD) included both MRI and MRA in patients over 7 years of age and those with abnormal TCD. Arteriography was performed in cases where a stenosis was suspected on TCD. Middle cerebral artery (MCA) and basilar artery (BA) velocities were significantly higher in the sickle cell hemoglobin SS group than in the hemoglobin SC group. Patients with a MCA mean velocity of over 1.90 m/s had stenoses found by arteriography. Patients with unilaterally undetectable MCA flow had experienced a stroke and MCA thrombosis was confirmed at MRA and arteriography. We concluded that TCD is valuable in detecting arterial stenosis in SCD and will lead to consideration of these patients for intensive therapy, such as bone marrow transplantation (BMT) or transfusion regimes. (orig.)

Detection of cerebrovascular disease in patients with sickle cell disease using transcranial Doppler sonography: correlation with MRI, MRA and conventional angiography

International Nuclear Information System (INIS)

Verlhac, S.; Bernaudin, F.; Tortrat, D.; Brugieres, P.; Mage, K.; Gaston, A.; Reinert, P.

1995-01-01

A prospective study of 58 patients with sickle cell disease (SCD) by transcranial Doppler sonography (TCD) included both MRI and MRA in patients over 7 years of age and those with abnormal TCD. Arteriography was performed in cases where a stenosis was suspected on TCD. Middle cerebral artery (MCA) and basilar artery (BA) velocities were significantly higher in the sickle cell hemoglobin SS group than in the hemoglobin SC group. Patients with a MCA mean velocity of over 1.90 m/s had stenoses found by arteriography. Patients with unilaterally undetectable MCA flow had experienced a stroke and MCA thrombosis was confirmed at MRA and arteriography. We concluded that TCD is valuable in detecting arterial stenosis in SCD and will lead to consideration of these patients for intensive therapy, such as bone marrow transplantation (BMT) or transfusion regimes. (orig.)

Transcranial doppler sonography in two patients who underwent decompressive craniectomy for traumatic brain swelling: report of two cases

Directory of Open Access Journals (Sweden)

Bor-Seng-Shu Edson

2004-01-01

Full Text Available The role of decompressive craniectomy in the treatment of severe posttraumatic cerebral swelling remains quite a controversial issue. To the best of our knowledge, there is no study demonstrating the effect of decompressive craniectomy on cerebral blood flow (CBF velocity by means of transcranial Doppler sonography (TCD. We present two patients who developed traumatic brain swelling and uncontrollable intracranial hypertension with coma and signs of transtentorial herniation. One patient underwent bifrontal, while the second, unilateral, frontotemporoparietal decompressive craniectomy with dural expansion. In both patients, TCD examinations were performed immediately before and after surgery to study the cerebral hemodynamic changes related to the operations. Pre and postoperative TCD examinations demonstrated a significant increase in blood flow velocity in the intracranial arteries in both subjects. In conclusion, our cases suggest that decompressive craniectomy with dural expansion may result in elevation of CBF velocity in patients with massive brain swelling. The increase in CBF velocity appears to occur not only in the decompressed hemisphere, but also on the opposite side.

Determination of hemispheric dominance with mental rotation using functional transcranial Doppler sonography and FMRI.

Science.gov (United States)

Hattemer, Katja; Plate, Annika; Heverhagen, Johannes T; Haag, Anja; Keil, Boris; Klein, Karl Martin; Hermsen, Anke; Oertel, Wolfgang H; Hamer, Hajo M; Rosenow, Felix; Knake, Susanne

2011-01-01

the aim of this study was to investigate specific activation patterns and potential gender differences during mental rotation and to investigate whether functional magnetic resonance imaging (fMRI) and functional transcranial Doppler sonography (fTCD) lateralize hemispheric dominance concordantly. regional brain activation and hemispheric dominance during mental rotation (cube perspective test) were investigated in 10 female and 10 male healthy subjects using fMRI and fTCD. significant activation was found in the superior parietal lobe, at the parieto-occipital border, in the middle and superior frontal gyrus bilaterally, and the right inferior frontal gyrus using fMRI. Men showed a stronger lateralization to the right hemisphere during fMRI and a tendency toward stronger right-hemispheric activation during fTCD. Furthermore, more activation in frontal and parieto-occipital regions of the right hemisphere was observed using fMRI. Hemispheric dominance for mental rotation determined by the 2 methods correlated well (P= .008), but did not show concordant results in every single subject. the neural basis of mental rotation depends on a widespread bilateral network. Hemispheric dominance for mental rotation determined by fMRI and fTCD, though correlating well, is not always concordant. Hemispheric lateralization of complex cortical functions such as spatial rotation therefore should be investigated using multimodal imaging approaches, especially if used clinically as a tool for the presurgical evaluation of patients undergoing neurosurgery. Copyright © 2009 by the American Society of Neuroimaging.

[The value of Doppler sonography in the detection of fetal hypoxia].

Science.gov (United States)

Aranyosi, János; Zatik, János; Juhász, A Gábor; Fülesdi, Béla; Major, Tamás

2002-10-27

Doppler ultrasound has become a part of routine antenatal fetal surveillance during the past two decades. It provides insight into the utero-placental and fetal arterial, venous circulation non-invasively. Doppler examination has a key role in the detection of hypoxic risk since abnormal blood flow patterns can be demonstrated before the clinical manifestation of fetal disorder. Doppler velocimetry facilitates judgment in the diagnosis, monitoring fetal well-being during pregnancy and labor, scheduling antenatal tests and timing delivery. Authors review the effects of chronic and acute hypoxia on fetal hemodynamics. On the basis of the present knowledge and experience a brief summary is given about the role of Doppler velocimetry in the early detection of hypoxic fetal jeopardy during pregnancy and labor.

Basal ganglia perfusion using dynamic color Doppler sonography in infants with hypoxic ischemic encephalopathy receiving therapeutic hypothermia: a pilot study.

Science.gov (United States)

Faingold, Ricardo; Cassia, Guilherme; Morneault, Linda; Saint-Martin, Christine; Sant'Anna, Guilherme

2016-10-01

The objective of this study was to evaluate the cerebral perfusion of the basal ganglia in infants with hypoxic-ischemic encephalopathy (HIE) receiving hypothermia using dynamic color Doppler sonography (CDS) and investigate for any correlation between these measurements and survival. Head ultrasound (HUS) was performed with a 9S4 MHz sector transducer in HIE infants submitted to hypothermia as part of their routine care. Measurements of cerebral perfusion intensity (CPI) with an 11LW4 MHz linear array transducer were performed to obtain static images and DICOM color Doppler videos of the blood flow in the basal ganglia area. Clinical and radiological data were evaluated retrospectively. The video images were analyzed by two radiologists using dedicated software, which allows automatic quantification of color Doppler data from a region of interest (ROI) by dynamically assessing color pixels and flow velocity during the heart cycle. CPI is expressed in cm/sec and is calculated by multiplying the mean velocity of all pixels divided by the area of the ROI. Three videos of 3 seconds each were obtained of the ROI, in the coronal plane, and used to calculate the CPI. Data are presented as mean ± SEM or median (quartiles). A total of 28 infants were included in this study: 16 male, 12 female. HUS was performed within the first 48 hours of therapeutic hypothermia treatment. CPI values were significantly higher in the seven non-survivors when compared to survivors (0.226±0.221 vs . 0.111±0.082 cm/sec; P=0.02). Increased perfusion intensity of the basal ganglia area within the first 48 of therapeutic hypothermia treatment was associated with poor outcome in neonates with HIE.

Transcranial Doppler for detection of cerebral ischaemia during carotid endarterectomy

DEFF Research Database (Denmark)

Jørgensen, L G; Schroeder, T V

1992-01-01

We evaluated transcranial Doppler sonography (TCD) for the detection of cerebral ischaemia during carotid endarterectomy in 30 male and 14 female patients with ipsilateral focal cerebro-vascular symptoms. Surgery was performed during halothane-nitrous oxide anaesthesia with moderate hypocapnia...

Tc-99m DTPA perfusion scintigraphy and color coded duplex sonography in the evaluation of minimal renal allograft perfusion

International Nuclear Information System (INIS)

Bair, H.J.; Platsch, G.; Wolf, F.; Guenter, E.; Becker, D.; Rupprecht, H.; Neumayer, H.H.

1997-01-01

Aim: The clinical impact of perfusion scintigraphy versus color coded Duplex sonography was evaluated, with respect to their potential in assessing minimal allograft perfusion in vitally threatened kidney transplants, i.e. oligoanuric allografts suspected to have either severe rejection or thrombosis of the renal vein or artery. Methods: From July 1990 to August 1994 the grafts of 15 out of a total of 315 patients were vitally threatened. Technetium-99m DTPA scintigraphy and color coded Duplex sonography were performed in all patients. For scintigraphic evaluation of transplant perfusion analog scans up to 60 min postinjection, and time-activity curves over the first 60 sec after injection of 370-440 MBq Tc-99m diethylenetriaminepentaacetate acid (DTPA) were used and classified by a perfusion score, the time between renal and iliac artery peaks (TDiff) and the washout of the renogram curve. Additionally, evaluation of excretion function and assessment of vascular or urinary leaks were performed. By color coded Duplex sonography the perfusion in all sections of the graft as well as the vascular anastomoses were examined and the maximal blood flow velocity (Vmax) and the resistive index (RI) in the renal artery were determined by means of the pulsed Doppler device. Pathologic-anatomical diagnosis was achieved by either biopsy or post-explant histology in all grafts. Results: Scintigraphy and color coded Duplex sonography could reliably differentiate minimal (8/15) and not perfused (7/15) renal allografts. The results were confirmed either by angiography in digital subtraction technique (DSA) or the clinical follow up. Conclusion: In summary, perfusion scintigraphy and color coded Duplex sonography are comparable modalities to assess kidney graft perfusion. In clinical practice scintigraphy and colorcoded Doppler sonography can replace digital subtraction angiography in the evaluation of minimal allograft perfusion. (orig.) [de

SELECTIVE AND NONSELECTIVE β-BLOCKERS IN PRIMARY OPEN ANGLE GLAUCOMA THERAPY – RESULTS OF COLOR DOPPLER SONOGRAPHY

Directory of Open Access Journals (Sweden)

Vukoslava Maričić-Došen

2002-12-01

Full Text Available Background. Primary open angle glaucoma (POAG is a syndrome of progressive optic neuropathy characterized by optic nerve head excavation and visual field defects. Poor correlation between IOP and progression of glaucoma disease sets vascular mechanism in the centre of attention. By Color Doppler sonography, quantification of blood flow changes in vessels, which supply optic nerve head, is possible. We wanted to find out whether there are changes in the circulation of central retinal artery and posterior ciliary arteries in patients with primary open angle glaucoma treated with selective or nonselective β -blockers.Methods. 44 patients (88 eyes were divided into two groups: group 1: 22 patients (44 eyes treated with selective β -blockers (Betaxolol 0.5% and group 2: 22 patients (44 eyes treated with nonselective β -blockers (Timolol 0.5%. Vascular indices (RI, PI were measured in the central retinal artery and posterior ciliary arteries.Results. We found decreased blood flow and increased vascular indices in both groups of patients, statistically significant difference between group 1 and group 2: blood flow velocity was higher and vascular indices were lower in group 1 (Betaxolol 0.5% compared to group 2 (Timolol 0..5%.Conclusions. Selective β -blockers (calcium channel blockers act more vasoactively and neuroprotectively comparing to nonselective β -blockers.

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

International Nuclear Information System (INIS)

Uzun, Hakan; Yazici, Burhan; Erdogmus, Besir; Kocabay, Kenan; Buyukkaya, Ramazan; Buyukkaya, Ayla; Yazgan, Omer

2009-01-01

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.

Contrast-enhanced sonography for quantitative assessment of portal hypertension in patients with liver cirrhosis.

Science.gov (United States)

Qu, En-Ze; Zhang, Ying-Cai; Li, Zhi-Yan; Liu, Yang; Wang, Jin-Rui

2014-11-01

The clinical utility of contrast-enhanced sonography in portal hypertension remains unclear. We explored the feasibility of using contrast-enhanced sonography for noninvasive assessment of portal venous pressure. Twenty healthy individuals (control group; 9 men; mean age, 46.4 years) and 18 patients with portal hypertension (15 men; mean age, 46.2 years) were enrolled in this study. The portal hypertension group included patients who underwent splenectomy and pericardial blood vessel disarticulation at our hospital from October 2010 to March 2011. One week before surgery, patients with portal hypertension underwent preoperative liver contrast-enhanced sonography. Two-dimensional, Doppler, and contrast-enhanced sonographic parameters were compared between the groups. Portal venous pressure was measured intraoperatively by portal vein puncture in the portal hypertension group, and its relationship with the other parameters was analyzed. The 2-dimensional, Doppler, and contrast-enhanced sonographic parameters differed between the groups (P Portal venous pressure was inversely correlated with the area under the portal vein/hepatic artery time-intensity curve ratio (Qp/Qa), portal vein/hepatic artery strength ratio (Ip/Ia), and portal vein/hepatic artery wash-in perfusion slope ratio (βp/βa), with correlation coefficients of -0.701, -0.625, and -0.494, respectively. Measurement of the liver contrast-enhanced sonographic parameters Qp/Qa, Ip/Ia, and βp/βa could be used as a new quantitative method for noninvasively assessing portal venous pressure. © 2014 by the American Institute of Ultrasound in Medicine.

Mammary blood supply in various diseases as evidenced by color Doppler sonography

International Nuclear Information System (INIS)

Kharchenko, V.P.; Rozhkova, N.I.; Zubovskij, G.A.; Medvedeva, N.A.

1993-01-01

Color dopplerosonography, traditional sonography, and mammography without contrast staining, as well as physical and pathomorphologic methods were used in examinations of the mammary glands of 76 women aged 18 to 65. Characteristic features of the blood supply to the gland were detected, and differential diagnostic criteria defined on the basis of these findings, to simplify differentiation between malignant and benign nodular formations and the diffuse changes in the mamma

Management of threatened abortion with real-time sonography.

Science.gov (United States)

Anderson, S G

1980-02-01

Real-time sonography was used to evaluate 158 patients with threatened abortion. Fetal motion was first detected during the seventh gestational week and with increasing frequency thereafter in 73 patients with viable pregnancies continuing to term. Only 2 of 65 patients who aborted demonstrated fetal motion. The presence or absence of fetal motion was most reliable after 7 weeks' gestation for establishing a prognosis for a given pregnancy. Seventy-two of 74 pregnancies with fetal motion continued to term, whereas 63 of 64 pregnancies without fetal motion aborted. A method for using real-time sonography in the management of threatened abortion is presented.

Prediction of delayed neurological deficit after subarachnoid haemorrhage: a CT blood load and Doppler velocity approach

International Nuclear Information System (INIS)

Grosset, D.G.; McDonald, I.; Cockburn, M.; Straiton, J.; Bullock, R.R.

1994-01-01

The predictive value of cranial computed tomography (CT) blood load and serial transcranial Doppler sonography for the development of delayed ischaemic neurological deficit was assessed in 121 patients following subarachnoid haemorrhage. Of the 121 patients, 81 (67 %) had thick layers of blood or haematoma, including intraventricular bleeding. The proportion of patients who developed delayed deficit was higher with increasing amounts of subarachnoid blood on the admission CT (51 % of 53 cases in Fisher grade 3; 35 % of 33 cases in grade 2; 28 % of 7 cases in grade 1, P < 0.01). Doppler velocities obtained from readings at least every 2 days following admission were higher in patients with delayed neurological deficit (peak velocity for grade 3 patients 176 ± 6 cm/s (mean ± SE), versus grade 2: 164 ± 7 cm/s; grade 4 149 ± 9, both P = 0.04, Mann-Whitney). Peak velocity and maximal 24-h rise tended to be higher within different CT grades in patients with a deficit than in those without; this difference was significant for grade 3 patients (P < 0.01). We conclude that a combined approach with CT and Doppler sonography provides greater predictive value for the development of delayed ischaemic neurological deficit than either test considered independently. The value of Doppler sonography may be greatest for patients with Fisher grade 3 blood, in whom the risk of delayed ischaemia is greatest. (orig.)

Three-dimensional colour Doppler of ductus venosus agenesis in ...

African Journals Online (AJOL)

was bilateral pleural effusion with generalised subcutaneous oedema suggestive of hydrops fetalis (Fig. 1B). Colour Doppler sonography revealed the umbilical vein draining into the portal sinus with non-visualisation of the DV, which would connect the portal sinus with the inferior vena cava (IVC) (Figs 1C and 1D). Hence ...

Value of Perfusion CT, Transcranial Doppler Sonography, and Neurological Examination to Detect Delayed Vasospasm after Aneurysmal Subarachnoid Hemorrhage

International Nuclear Information System (INIS)

Kunze, E.; Raslan, F.; Stetter, Ch.; Lee, J.Y.; Solymosi, L.; Ernestus, R.I.; Vince, G.H.; Westermaier, Th.; Pham, M.; Solymosi, L.

2012-01-01

Background. If detected in time, delayed cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) may be treated by balloon angioplasty or chemical vasospasmolysis in order to enhance cerebral blood flow (CBF) and protect the brain from ischemic damage. This study was conceived to compare the diagnostic accuracy of detailed neurological examination, Transcranial Doppler Sonography (TCD), and Perfusion-CT (PCT) to detect angiographic vasospasm. Methods. The sensitivity, specificity, positive and negative predictive values of delayed ischemic neurological deterioration (DIND), pathological findings on PCT-maps, and accelerations of the mean flow velocity (MVF) were calculated. Results. The accuracy of DIND to predict angiographic vasospasm was 0.88. An acceleration of MFV in TCD (>140 cm/s) had an accuracy of 0.64, positive PCT-findings of 0.69 with a higher sensitivity, and negative predictive value than TCD. Interpretation. Neurological assessment at close intervals is the most sensitive and specific parameter for cerebral vasospasm. PCT has a higher accuracy, sensitivity and negative predictive value than TCD. If detailed neurological evaluation is possible, it should be the leading parameter in the management and treatment decisions. If patients are not amenable to detailed neurological examination, PCT at regular intervals is a helpful tool to diagnose secondary vasospasm after aneurysmal SAH

The mechanism of mid-latitude Pi2 waves in the upper ionosphere as revealed by combined Doppler and magnetometer observations

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V. A. Pilipenko

2013-04-01

Full Text Available The interpretation of simultaneous ionospheric Doppler sounding and ground magnetometer observations of low-latitude Pi2 waves is revised. We compare the theoretical estimates of the ionospheric Doppler velocity for the same amplitude of the ground magnetic disturbances produced by a large-scale compressional mode and an Alfvén mode. The plasma vertical displacement caused by the wave electric field is shown to be the dominating effect. Taking into account the correction of the previous paper, the observations of low-latitude Pi2 in the F layer ionosphere by Doppler sounding and SuperDARN (Super Dual Auroral Radar Network radars give consistent results. We suggest that the Doppler response to Pi2 waves is produced by the Alfvén wave component, but not the fast-mode component, whereas the ground magnetic signal is composed from both Alfvén and fast magnetosonic modes.

Does color Doppler sonography improve the clinical assessment of patients with acute scrotum?

International Nuclear Information System (INIS)

Pepe, Pietro; Panella, Paolo; Pennisi, Michele; Aragona, Francesco

2006-01-01

Introduction and objectives: Our experience concerning the use of color Doppler sonography (CDS) in the differential diagnosis of acute scrotum is reported. Material and methods: From July 2000 to July 2005, 155 patients (median 17.2 years) were admitted with a diagnosis of acute scrotum (unilateral in 150 cases, bilateral in 5). Along with a careful anamnesis and the physical exam, all patients underwent a CDS study of the scrotal content using a sonograph GE Logiq 500 with a multifrequency (7.5-10 MHz) linear probe Small Part. The following CDS parameters were evaluated: intensity of the color-power signal on the testicular parenchyma and on the epididymis; systolic peak velocity (SPV) and telediastolic velocity (TDV) in correspondence of the gonadal hilum. Ultrasound and flowmetry parameters registered on the painful testis were compared with those registered on the healthy controlateral testis. The reduction/absence versus the increase of color-power signal in the parenchyma and the reduction/absence versus the increase of SPV and TDV in the centripetal intratesticular arteries were considered presumptive of testicular torsion versus orchiepididymitis. Results: The results only refer to the 150 patients (300 testis) with acute monolateral scrotum. The clinical picture and the physical exam suggested a torsion of the spermatic cord in 40 cases, a spontaneous de-torsion in 5, an orchiepididymitis in 80, a blunt scrotal trauma in 15, a bulky epididymal cyst or a hydrocele in 4 and a testicular pain of unknown etiology in the remaining 6 cases. Standard US was pathological in 95 patients (63.3%); CDS was pathologic in 70 patients and in 42 of them suggested a testicular torsion. Fifty-three patients underwent surgical exploration: among 42 patients with a presumptive diagnosis of testicular torsion, the diagnosis was confirmed in 22 cases, no anomaly was found in 16 cases and in 4 patients a torsion of testicular appendix was found. The rupture of the tunica

High-frequency dual mode pulsed wave Doppler imaging for monitoring the functional regeneration of adult zebrafish hearts

OpenAIRE

Kang, Bong Jin; Park, Jinhyoung; Kim, Jieun; Kim, Hyung Ham; Lee, Changyang; Hwang, Jae Youn; Lien, Ching-Ling; Shung, K. Kirk

2015-01-01

Adult zebrafish is a well-known small animal model for studying heart regeneration. Although the regeneration of scars made by resecting the ventricular apex has been visualized with histological methods, there is no adequate imaging tool for tracking the functional recovery of the damaged heart. For this reason, high-frequency Doppler echocardiography using dual mode pulsed wave Doppler, which provides both tissue Doppler (TD) and Doppler flow in a same cardiac cycle, is developed with a 30 ...

Assessing the usefulness of B-mode and colour Doppler sonography, and measurements of circulating progesterone concentrations for determining ovarian responses in superovulated ewes.

Science.gov (United States)

Oliveira, Mef; Ribeiro, I F; Rodriguez, Mgk; Maciel, G S; Fonseca, J F; Brandão, F Z; Bartlewski, P M

2018-06-01

The main goal of this study was to assess the usefulness of two imaging modalities, namely the B-mode and colour Doppler sonography, and serum progesterone (P 4 ) concentrations for determining the ovarian response in superovulated ewes. Twenty-four sexually mature Santa Inês ewes underwent the superovulatory treatment consisting of eight injections of porcine FSH (total dose of 200 or 133 or 100 mg; n = 8 ewes/total dose) given at 12-hr intervals and initiated 48 hr before CIDR ® (Pfizer Inc., Auckland, New Zealand) removal. Six days after natural mating, the ovaries of all donor ewes were visualized and examined with transrectal ultrasonography and then with videolaparoscopy to identify and enumerate corpora lutea (CL) and luteinized unovulated follicles (LUFs). Jugular blood samples were collected just prior to ovarian examinations. The total number of CL (r = .78 and 0.83, p ewes. © 2018 Blackwell Verlag GmbH.

Association between two distinct executive tasks in schizophrenia: a functional transcranial Doppler sonography study

Directory of Open Access Journals (Sweden)

Theodoridou Anastasia

2006-05-01

Full Text Available Abstract Background Schizophrenia is a severe mental disorder involving impairments in executive functioning, which are important cognitive processes that can be assessed by planning tasks such as the Stockings of Cambridge (SOC, and tasks of rule learning/abstraction such as the Wisconsin Card Sorting Test (WCST. We undertook this study to investigate the association between performance during separate phases of SOC and WCST, including mean cerebral blood flow velocity (MFV measurements in chronic schizophrenia. Methods Functional transcranial Doppler sonography (fTCD was used to assess bilateral MFV changes in the middle (MCA and anterior (ACA cerebral arteries. Twenty-two patients with chronic schizophrenia and 20 healthy subjects with similar sociodemographic characteristics performed SOC and WCST during fTCD measurements of the MCA and the ACA. The SOC was varied in terms of easy and difficult problems, and also in terms of separate phases, namely mental planning and movement execution. The WCST performance was assessed separately for maintaining set and set shifting. This allowed us to examine the impact of problem difficulty and the impact of separate phases of a planning task on distinct intervals of WCST. Simultaneous registration of MFV was carried out to investigate the linkage of brain perfusion during the tasks. Results In patients, slowing of movement execution during easy problems (SOC was associated with slowing during maintaining set (WCST (P Conclusion The results of this study demonstrate performance and brain perfusion abnormalities in the association pattern of two different tasks of executive functioning in schizophrenia, and they support the notion that executive functions have a pathological functional correlate predominantly in the lateral hemispheres of the brain. This study also underpins the scientific potential of fTCD in assessing brain perfusion in patients with schizophrenia.

Duplex sonography and magnetic resonance imaging in the clarification of nephrological complications after renal transplant

International Nuclear Information System (INIS)

Gueckel, C.; Krestin, G.P.; Wienand, P.

1989-01-01

A prospective study compared Duplex sonography and magnetic resonance imaging in evaluating renal transplant. Hundred and two Duplex sonographic and 24 MR examinations were performed and correlated with clinical course or biopsy. All normal renal allografts, 6 transplants with acute tubular necrosis and 2 cases of cyclosporin toxicity had normal Doppler waveforms, whereas 9 renal transplants with evidence of interstitial rejection by biopsy showed an obliteration or reversal of diastolic flow. MR imaging was less specific in identifying allograft rejection. There were false positive results in normal renal transplants, allografts with acute tubular necrosis and after rejection therapy. With regard to cost, accessibility and specificity, Duplex sonography is the method of choice for the evaluation of renal allografts. (orig.) [de

Diagnostic value of high-resolution B-mode and power-mode sonography in the follow-up of thyroid cancer.

Science.gov (United States)

Görges, Rainer; Eising, E G; Fotescu, D; Renzing-Köhler, K; Frilling, A; Schmid, K W; Bockisch, A; Dirsch, O

2003-02-01

Ultrasonography is an established diagnostic modality in the follow-up of thyroid cancer. Color flow Doppler has been proposed by some authors as an additional tool for differentiating benign from malignant cervical lesions in various types of head and neck cancer. Over the last few years, a new generation of high-resolution ultrasound platforms with the "power-mode" feature has become available, that also enables the imaging of small vessel blood flow. The objective of our study was to find ways of optimizing the differentiation of benign and malignant cervical tumors in thyroid cancer follow-up by means of sonography. Hundred and twelve cervical lesions in 90 patients with thyroid cancer were evaluated by high-end ultrasonography (Sonoline Elegra, Siemens) using a small-part transducer (7.5 L 40, Siemens). B-mode sonography was performed at a frequency of 8 MHz. The Solbiati index (SI= ratio of largest to smallest diameter), configuration, echogenicity, intranodular structures, and margins were assessed. Perinodular and intranodular blood flow was evaluated by color flow Doppler (PRF 1250 Hz for conventional color flow Doppler, 868 Hz for power-mode Doppler). Possible malignancy was validated by histology, cytology, scintigraphy, and follow-up. Thirty five lesions were benign (diameter 0.4-3.0 cm) and 77 were malignant (0.4-5.4 cm). The patients were randomized into a test group and a learning group to determine the diagnostic value of various ultrasound criteria by means of statistical analysis. In the learning group, decision rules based on the dichotomized criteria were developed using a logistic regression model. Sensitivity and specificity of these decision rules were then evaluated in the test group. The presence of an echocomplex pattern or irregular hyperechoic small intranodular structures (criterion A) and the presence of an irregular diffuse intranodular blood flow (criterion B) are the best indicators of malignancy, whereas an SI >2 is highly

Propagation of gravity waves and spread F in the low-latitude ionosphere over Tucumán, Argentina, by continuous Doppler sounding: First results

Czech Academy of Sciences Publication Activity Database

Chum, Jaroslav; Bonomi, F. A. M.; Fišer, Jiří; Cabrera, M. A.; Ezquer, R. G.; Burešová, Dalia; Laštovička, Jan; Baše, Jiří; Hruška, František; Molina, M. G.; Ise, J. E.; Cangemi, J. I.; Šindelářová, Tereza

2014-01-01

Roč. 119, č. 8 (2014), s. 6954-6965 ISSN 2169-9380 R&D Projects: GA ČR(CZ) GAP209/12/2440; GA ČR GP13-09778P Institutional support: RVO:68378289 Keywords : low latitude ionosphere * Ionospheric irregularities * equatorial spread F * gravity waves * scintillation * remote sensing * Doppler sounding Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 3.426, year: 2014 http://onlinelibrary.wiley.com/doi/10.1002/2014JA020184/abstract

Normal reference values for vertebral artery flow volume by color Doppler sonography in Korean adults

Energy Technology Data Exchange (ETDEWEB)

Hong, Hyun Sook; Cha, Jang Gyu; Park, Seong Jin; Joh, Joon Hee; Park, Jai Soung; Kim, Dae Ho; Lee, Hae Kyung; Ahn, Hyun Cheol [Soonchunhyang University Bucheon Hospital, Bucheon (Korea, Republic of)

2003-09-15

Vertebrobasilar ischemia has been attributed to a reduction of net vertebral artery flow volume. This study was to establish the reference values for the flow volume of the vertebral artery using color Doppler sonography in the normal Korea adults. Thirty five normal Korea adults without any underlying disease including hypertension, hyperlipidemia, diabetes, heart disease, obesity (body mas index>30), or carotid artery stenosis was included. There were 17 males and 18 females, age ranged from 20 to 53 years (average=32.86 years). Flow velocities and vessel diameters were recorded in the intertransverse (V2) segment, usually at C5-6 level, bilaterally. The flow volume (Q) was calculated. (Q=time averaged mean velocity x cross sectional area of vessel) A lower Flow velocity and smaller vessel diameter were measured on the right side compared to those of the left side, resulting in a lower flow volume. The calculated flow volumes using the equation were 77.0 +- 39.7 ml/min for the right side and 127.6 +- 71.0 ml/min for the left side (p=0.0001) while the net vertebral artery flow volume was 204.6 +- 81.8 ml/min. Decrease in the vertebral artery flow volume was statistically significant with advanced age. (r=-0.36, p=0.032). Vertebral artery blood flow volume was 191.20 +- 59.19 ml/min in male, and 217.28 +- 98.67 ml/min in female (p=0.6). The normal range for the net vertebral artery flow volume defined by the 5th to 95th percentiles was between 110.06 and 364.1 ml/min. The normal range for the net vertebral artery flow volume was between 110.06 and 364.1 ml/min. Vertebral artery flow volume decreased with the increase of age. However, gender did not affect the blood flow volume.

Normal reference values for vertebral artery flow volume by color Doppler sonography in Korean adults

International Nuclear Information System (INIS)

Hong, Hyun Sook; Cha, Jang Gyu; Park, Seong Jin; Joh, Joon Hee; Park, Jai Soung; Kim, Dae Ho; Lee, Hae Kyung; Ahn, Hyun Cheol

2003-01-01

Vertebrobasilar ischemia has been attributed to a reduction of net vertebral artery flow volume. This study was to establish the reference values for the flow volume of the vertebral artery using color Doppler sonography in the normal Korea adults. Thirty five normal Korea adults without any underlying disease including hypertension, hyperlipidemia, diabetes, heart disease, obesity (body mas index>30), or carotid artery stenosis was included. There were 17 males and 18 females, age ranged from 20 to 53 years (average=32.86 years). Flow velocities and vessel diameters were recorded in the intertransverse (V2) segment, usually at C5-6 level, bilaterally. The flow volume (Q) was calculated. (Q=time averaged mean velocity x cross sectional area of vessel) A lower Flow velocity and smaller vessel diameter were measured on the right side compared to those of the left side, resulting in a lower flow volume. The calculated flow volumes using the equation were 77.0 ± 39.7 ml/min for the right side and 127.6 ± 71.0 ml/min for the left side (p=0.0001) while the net vertebral artery flow volume was 204.6 ± 81.8 ml/min. Decrease in the vertebral artery flow volume was statistically significant with advanced age. (r=-0.36, p=0.032). Vertebral artery blood flow volume was 191.20 ± 59.19 ml/min in male, and 217.28 ± 98.67 ml/min in female (p=0.6). The normal range for the net vertebral artery flow volume defined by the 5th to 95th percentiles was between 110.06 and 364.1 ml/min. The normal range for the net vertebral artery flow volume was between 110.06 and 364.1 ml/min. Vertebral artery flow volume decreased with the increase of age. However, gender did not affect the blood flow volume.

Carotid Doppler ultrasound findings in patients with left ventricular assist devices.

Science.gov (United States)

Cervini, Patrick; Park, Soon J; Shah, Dipesh K; Penev, Irina E; Lewis, Bradley D

2010-12-01

Left ventricular assist devices (LVADs) have been used to treat advanced heart failure refractory to medical management, as bridge therapy to myocardial recovery, as bridge therapy to cardiac transplantation, or as destination therapy for patients with unfavorable transplant candidacy. Neurologic complications are some of the most common and devastating complications in these patients. Preoperative carotid ultrasound is, therefore, a standard evaluation in patients at risk for cerebrovascular disease. Postoperative carotid artery Doppler sonography is performed in those patients with neurologic symptoms. It is likely, therefore, that sonographers, radiologists, and other physicians working in a center where LVADs are implanted will likely encounter a carotid artery Doppler study in this patient group. To our knowledge, the carotid Doppler findings in these patients have never been published. We review the Doppler ultrasound findings in 6 patients after LVAD insertion.

HF doppler sounder measurements of the ionospheric signatures of small scale ULF waves

Directory of Open Access Journals (Sweden)

L. J. Baddeley

2005-07-01

Full Text Available An HF Doppler sounder, DOPE (DOppler Pulsation Experiment with three azimuthally-separated propagation paths is used to provide the first statistical examination of small scale-sized, high m waves where a direct measurement of the azimuthal wavenumber m, is made in the ionosphere. The study presents 27 events, predominantly in the post-noon sector. The majority of events are Pc4 waves with azimuthal m numbers ranging from –100 to –200, representing some of the smallest scale waves ever observed in the ionosphere. 4 Pc5 waves are observed in the post-noon sector. The fact that measurements for the wave azimuthal m number and the wave angular frequency are available allows the drift-bounce resonance condition to be used to hypothesise potential particle populations which could drive the waves through either a drift or drift-bounce resonance interaction mechanism. These results are compared with the statistical study presented by Baddeley et al. (2004 which investigated the statistical likelihood of such driving particle populations occurring in the magnetospheric ring current. The combination of these two studies indicates that any wave which requires a possible drift resonance interaction with particles of energies >60 keV, is statistically unlikely to be generated by such a mechanism. The evidence presented in this paper therefore suggests that in the pre-noon sector the drift-bounce resonance mechanism is statistically more likely implying an anti-symmetric standing wave structure while in the post-noon sector both a drift or drift-bounce resonance interaction is statistically possible, indicating both symmetric and anti-symmetric standing mode structures. A case study is also presented investigating simultaneous observations of a ULF wave in ground magnetometer and DOPE data. The event is in the lower m range of the statistical study and displays giant pulsation (Pg characteristics.

Keywords

HF doppler sounder measurements of the ionospheric signatures of small scale ULF waves

Directory of Open Access Journals (Sweden)

L. J. Baddeley

2005-07-01

Full Text Available An HF Doppler sounder, DOPE (DOppler Pulsation Experiment with three azimuthally-separated propagation paths is used to provide the first statistical examination of small scale-sized, high m waves where a direct measurement of the azimuthal wavenumber m, is made in the ionosphere. The study presents 27 events, predominantly in the post-noon sector. The majority of events are Pc4 waves with azimuthal m numbers ranging from –100 to –200, representing some of the smallest scale waves ever observed in the ionosphere. 4 Pc5 waves are observed in the post-noon sector. The fact that measurements for the wave azimuthal m number and the wave angular frequency are available allows the drift-bounce resonance condition to be used to hypothesise potential particle populations which could drive the waves through either a drift or drift-bounce resonance interaction mechanism. These results are compared with the statistical study presented by Baddeley et al. (2004 which investigated the statistical likelihood of such driving particle populations occurring in the magnetospheric ring current. The combination of these two studies indicates that any wave which requires a possible drift resonance interaction with particles of energies >60 keV, is statistically unlikely to be generated by such a mechanism. The evidence presented in this paper therefore suggests that in the pre-noon sector the drift-bounce resonance mechanism is statistically more likely implying an anti-symmetric standing wave structure while in the post-noon sector both a drift or drift-bounce resonance interaction is statistically possible, indicating both symmetric and anti-symmetric standing mode structures. A case study is also presented investigating simultaneous observations of a ULF wave in ground magnetometer and DOPE data. The event is in the lower m range of the statistical study and displays giant pulsation (Pg characteristics. Keywords. Ionosphere (Ionosphere

New sub-Doppler absorption resonances in a thin gas cell produced by means of a running monochromatic wave

International Nuclear Information System (INIS)

Tajalli, H; Ahmadi, S; Izmailov, A Ch

2002-01-01

A theoretical investigation is carried out through the interaction of the plane running monochromatic light wave, having an arbitrary intensity, with atoms (molecules) of a rarefied gas in the plane cell (at the normal incidence of the wave). Cases of closed and open resonance transitions from the non-degenerate ground (or metastable) quantum level are considered. Possible sub-Doppler resonances are analysed in the wave absorption, caused by the transient establishment of the optical coherence on the transition, Rabi oscillations between its levels, and optical pumping during the free flights of particles between the walls of the cell. Results of the previous works on given problems are generalized, which were obtained at definite restrictions on the wave intensity and cell length. Moreover, non-trivial sub-Doppler spectral structures, resulting as a consequence of the dependence of the absorption saturation on the transit relaxation of particles, have been established and investigated. Such structures may consist of a number of peaks and dips caused by Rabi oscillations between the transition levels. The results obtained can be used in sub-Doppler spectroscopy and for the stabilization of laser frequencies in thin gas cells

Ideal Positions: 3D Sonography, Medical Visuality, Popular Culture.

Science.gov (United States)

Seiber, Tim

2016-03-01

As digital technologies are integrated into medical environments, they continue to transform the experience of contemporary health care. Importantly, medicine is increasingly visual. In the history of sonography, visibility has played an important role in accessing fetal bodies for diagnostic and entertainment purposes. With the advent of three-dimensional (3D) rendering, sonography presents the fetus visually as already a child. The aesthetics of this process and the resulting imagery, made possible in digital networks, discloses important changes in the relationship between technology and biology, reproductive health and political debates, and biotechnology and culture.

Doppler radar flowmeter

Science.gov (United States)

Petlevich, Walter J.; Sverdrup, Edward F.

1978-01-01

A Doppler radar flowmeter comprises a transceiver which produces an audio frequency output related to the Doppler shift in frequency between radio waves backscattered from particulate matter carried in a fluid and the radiated radio waves. A variable gain amplifier and low pass filter are provided for amplifying and filtering the transceiver output. A frequency counter having a variable triggering level is also provided to determine the magnitude of the Doppler shift. A calibration method is disclosed wherein the amplifier gain and frequency counter trigger level are adjusted to achieve plateaus in the output of the frequency counter and thereby allow calibration without the necessity of being able to visually observe the flow.

Acetazolamide stimulation test in patients with unilateral internal carotid artery stenosis using Tc-99m HMPAO SPECT and transcranial doppler sonography

Energy Technology Data Exchange (ETDEWEB)

Hyun, I. Y.; Na, J. H. [Inha University Hospital, Incheon (Korea, Republic of)

2007-07-01

We compared perfusion reserve by acetazolamide (ACZ) challenged brain perfusion SPECT and cerebral vasoreactivity (CVR) by transcranial Doppler sonography (TCD) in patients with unilateral internal carotid artery stenosis. This study was conducted prospectively in 37 consecutive patients with angiographically proven unilateral internal carotid artery stenosis (stenosis> 50%). We estimated % CVR (100? {l_brace}post-ACZ mean velocity (cm/sec) - Pre-ACZ mean velocity (cm/sec){r_brace} / pre-ACZ mean velocity) by TCD. The % CVR was compared with perfusion reserve of SPECT. The % CVR of MCA and ICA was significantly decreased in the ipsilateral side to the carotid stenosis (p<0.05). The CVR impairment was more severe when cerebral infarct is already developed (p<0.01). There was a significant correlation between the degree of carotid stenosis and the CVR (p<0.01). In the area of impaired perfusion reserve on the SPECT, the estimated CVR by TCD was significantly lower (p<0.05), even to the negative value, implying that there is actually steal phenomenon in that area. ACZ challenge can actually decrease cerebral blood flow in the area of impaired perfusion reserve on brain SPECT. So we should be very cautiously performing in ACZ challenge especially when there is a severe carotid stenosis because there is a possibility of developing hemodynamic stroke.

Color Doppler, power Doppler and B-flow ultrasound in the assessment of ICA stenosis: Comparison with 64-MD-CT angiography

International Nuclear Information System (INIS)

Clevert, D.A.; Johnson, T.; Flach, P.M.; Strautz, T.I.; Becker, C.; Reiser, M.; Jung, E.M.; Ritter, G.; Gallegos, M.T.; Kubale, R.

2007-01-01

The purpose of this study is to investigate the diagnostic potential of color-coded Doppler sonography (CCDS), power-Doppler (PD) and B-flow ultrasound in assessing the degree of extracranial internal carotid artery (ICA) stenosis in comparison to CT-angiography (MD-CTA). Thirty-two consecutive patients referred for CTA with 41 ICA-stenoses were included in this prospective study. MD-CTA was performed using a 64 row scanner with a CTDIvol of 13.1 mGy/cm. In CTA, CCDS, PD and B-flow, the degree of stenosis was evaluated by the minimal intrastenotic diameter in comparison to the poststenotic diameter. Two radiologists performed a quantitative evaluation of the stenoses in consensus blinded to the results of ultrasound. These were correlated to CTA, CCDS, PD and B-flow, intraoperative findings and clinical follow-up. Grading of the stenoses in B-flow ultrasound outperformed the other techniques in terms of accuracy with a correlation coefficient to CTA of 0.88, while PD and CCDS measurements yield coefficients of 0.74 and 0.70. Bland-Altman analysis additionally shows a very little bias of the three US methods between 0.5 and 3.2 %. There is excellent correlation (coefficient 0.88, CI 0.77-0.93) with 64-MD-CTA and B-flow ultrasound in terms of accuracy for intrastenotic and poststenotic diameter. Duplex sonography is useful for screening purposes. (orig.)

Asset of Doppler Vascular Imaging and CTA in Diagnosis of Coagulation Disturbances in Pregnancy and Puerperium - case study

International Nuclear Information System (INIS)

Leskova, M.; Slobodnikova, J.

2009-01-01

Importance of earlier diagnosis of trombophilia. Trombophilia - its impression on development venous trombosis specially in the case of young woman with repeated spontaneous abortions. Value of not-invasive imaging methods (Doppler sonography and CT angiography ) in diagnosis deep phlebotrombosis. (author)

Magnetic resonance tomography and ultrasound in rheumatology; MRT und Sonographie in der Rheumatologie

Energy Technology Data Exchange (ETDEWEB)

Kainberger, F. [Universitaetsklinik fuer Radiodiagnostik, Ludwig-Boltzmann-Inst. fuer Physikalische und Radiologische Tumordiagnostik, Wien (Austria); Czerny, C. [Universitaetsklinik fuer Radiodiagnostik, Ludwig-Boltzmann-Inst. fuer Physikalische und Radiologische Tumordiagnostik, Wien (Austria); Trattnig, S. [Universitaetsklinik fuer Radiodiagnostik, Ludwig-Boltzmann-Inst. fuer Physikalische und Radiologische Tumordiagnostik, Wien (Austria); Lack, W. [Universitaetsklinik fuer Orthopaedie, Wien (Austria); Machold, K. [Universitaetsklinik fuer Innere Medizin III, Wien (Austria). Abt. fuer Rheumatologie; Graninger, W. [Universitaetsklinik fuer Innere Medizin III, Wien (Austria). Abt. fuer Rheumatologie

1996-08-01

Technical innovations and software improvements in magnetic resonance imaging (MRI) and high-resolution sonography (US) have definitely influenced the diagnostic imaging of rheumatic diseases. For MRI, improvements in surface coils, dedicated low-field systems (0.2 T), and software improvements (shorter acquisition times and refinements of fat suppressing techniques) must be mentioned. For sonography, the main innovations concern the development of higher transducer frequencies (7-15 Mhz) and power Doppler imaging. Clinical evaluations have shown that MRI and US are most useful in cases of suspected rheumatic disease with negative plain film radiographs and for documenting the course of the disease, diagnosing of early rheumatoid arthritis, making a differential diagnosis in clinically unclear rheumatic diseases, investigating vascularization, and quantifying pannus formation. In order to improve diagnostic efficacy the role of MRI and US in the management of patients with rheumatic disease should be reconsidered. (orig.) [Deutsch] Technische Innovationen in Hard- und Software von Magnetresonanztomographie (MRT) und Sonographiegeraeten haben die bildgebende Diagnostik in der Rheumatologie massgeblich beeinflusst (Verbesserungen der Oberflaechenspulen mit hohen Gradientenfeldern, dedizierte Niederfeldgeraete, Softwareverbesserungen in Form von kuerzeren Aquisitionszeiten und Verfeinerungen in der Fettunterdrueckung, hoehere Transducerfrequenzen zwischen 7 und 15 Mhz, Powerdopplerverfahren). Fuer die klinische Anwendung bedeutet dies, dass MRT und Sonographie als bildgebende Zusatzverfahren nach der Anfertigung konventioneller Roentgenaufnahmen anzuwenden sind, wenn diese unauffaellige Resultate ergeben oder spezielle Fragen zur Schwere des Krankheitsprozesses bzw. von Folgeerscheinungen zu beantworten sind. Im besonderen betrifft dies den Nachweis der Frueharthritis, die Differentialdiagnose klinisch nicht klar einzuordnender Krankheitsbilder und die Bestimmung des

D-dimer assay for deep vein thrombosis: its role with colour Doppler sonography

Energy Technology Data Exchange (ETDEWEB)

Bradley, M.; Bladon, J.; Barker, H

2000-07-01

AIM: To evaluate the role of a negative D-dimer assay in the initial management of patients with clinically suspected deep venous thrombosis (DVT), using colour Doppler ultrasound as the primary diagnostic technique. MATERIALS AND METHODS: A double-blind prospective trial was performed on 143 patients with clinically suspected DVT. All patients underwent a D-dimer assay prior to anticoagulant therapy. DVT was confirmed or excluded by diagnostic colour Doppler ultrasound within 24 h of presentation. RESULTS: In nearly one-third of the cases (31.8%), Doppler ultrasound was positive. The D-dimer assay demonstrated a sensitivity of 97.7% with only one false-negative, but the specificity was low at 48.9% with 45 false-positive results. The positive predictive value for D-dimer assay was 48.8%, whilst the important negative predictive value was 98%. CONCLUSION: If D-dimer was used to screen for DVT, and patients with negative results were not imaged, then the imaging workload could be reduced by 35%. In this study one small calf vein thrombus would have been missed by adopting this practice. Bradley, M. (2000)

Attenuated Vector Tomography -- An Approach to Image Flow Vector Fields with Doppler Ultrasonic Imaging

International Nuclear Information System (INIS)

Huang, Qiu; Peng, Qiyu; Huang, Bin; Cheryauka, Arvi; Gullberg, Grant T.

2008-01-01

The measurement of flow obtained using continuous wave Doppler ultrasound is formulated as a directional projection of a flow vector field. When a continuous ultrasound wave bounces against a flowing particle, a signal is backscattered. This signal obtains a Doppler frequency shift proportional to the speed of the particle along the ultrasound beam. This occurs for each particle along the beam, giving rise to a Doppler velocity spectrum. The first moment of the spectrum provides the directional projection of the flow along the ultrasound beam. Signals reflected from points further away from the detector will have lower amplitude than signals reflected from points closer to the detector. The effect is very much akin to that modeled by the attenuated Radon transform in emission computed tomography.A least-squares method was adopted to reconstruct a 2D vector field from directional projection measurements. Attenuated projections of only the longitudinal projections of the vector field were simulated. The components of the vector field were reconstructed using the gradient algorithm to minimize a least-squares criterion. This result was compared with the reconstruction of longitudinal projections of the vector field without attenuation. If attenuation is known, the algorithm was able to accurately reconstruct both components of the full vector field from only one set of directional projection measurements. A better reconstruction was obtained with attenuation than without attenuation implying that attenuation provides important information for the reconstruction of flow vector fields.This confirms previous work where we showed that knowledge of the attenuation distribution helps in the reconstruction of MRI diffusion tensor fields from fewer than the required measurements. In the application of ultrasound the attenuation distribution is obtained with pulse wave transmission computed tomography and flow information is obtained with continuous wave Doppler

[Elastography as an additional tool in breast sonography. Technical principles and clinical applications].

Science.gov (United States)

Rjosk-Dendorfer, D; Reichelt, A; Clevert, D-A

2014-03-01

In recent years the use of elastography in addition to sonography has become a routine clinical tool for the characterization of breast masses. Whereas free hand compression elastography results in qualitative imaging of tissue stiffness due to induced compression, shear wave elastography displays quantitative information of tissue displacement. Recent studies have investigated the use of elastography in addition to sonography and improvement of specificity in differentiating benign from malignant breast masses could be shown. Therefore, additional use of elastography could help to reduce the number of unnecessary biopsies in benign breast lesions especially in category IV lesions of the ultrasound breast imaging reporting data system (US-BI-RADS).

Impact of real-time virtual sonography, a coordinated sonography and MRI system that uses an image fusion technique, on the sonographic evaluation of MRI-detected lesions of the breast in second-look sonography.

Science.gov (United States)

Nakano, Shogo; Kousaka, Junko; Fujii, Kimihito; Yorozuya, Kyoko; Yoshida, Miwa; Mouri, Yukako; Akizuki, Miwa; Tetsuka, Rie; Ando, Takahito; Fukutomi, Takashi; Oshima, Yukihiko; Kimura, Junko; Ishiguchi, Tsuneo; Arai, Osamu

2012-08-01

The aim of this study was to verify the utility of second-look sonography using real-time virtual sonography (RVS)-a coordinated sonography with an MRI system that uses an image fusion technique with magnetic navigation-on the sonographic evaluation of MRI-detected lesions of the breast. Of the 196 consecutive patients who were examined with breast MRI in our hospital from 2006 to 2009, those patients who underwent second-look sonography to identify MRI-detected lesions were enrolled in this study. MRI was performed using a 1.5-T imager with the patient in a supine position. To assess the efficacy benefits of RVS, the correlations between lesion detection rates, MRI features, distribution, and histopathological classification on second-look sonography using conventional B-mode or RVS were analyzed. Of the 196 patients, 55 (28 %) demonstrated 67 lesions initially detected by MRI, followed by second-look sonography. Of the 67 MRI-detected lesions, 18 (30 %) were identified with second-look sonography using conventional B-mode alone, whereas 60 (90 %) lesions were detected with second-look sonography using RVS (p use of RVS on second-look sonography significantly increases the sonographic detection rate of MRI-detected lesions without operator dependence.

Observation of fast-ion Doppler-shifted cyclotron resonance with shear Alfven waves

International Nuclear Information System (INIS)

Zhang Yang; Heidbrink, W. W.; Boehmer, H.; McWilliams, R.; Vincena, S.; Carter, T. A.; Gekelman, W.; Leneman, D.; Pribyl, P.

2008-01-01

The Doppler-shifted cyclotron resonance (ω-k z v z =Ω f ) between fast ions and shear Alfven waves is experimentally investigated (ω, wave frequency; k z , axial wavenumber; v z , fast-ion axial speed; Ω f , fast-ion cyclotron frequency). A test particle beam of fast ions is launched by a Li + source in the helium plasma of the LArge Plasma Device (LAPD) [W. Gekelman, H. Pfister, Z. Lucky, J. Bamber, D. Leneman, and J. Maggs, Rev. Sci. Instrum. 62, 2875 (1991)], with shear Alfven waves (SAW) (amplitude δ B/B up to 1%) launched by a loop antenna. A collimated fast-ion energy analyzer measures the nonclassical spreading of the beam, which is proportional to the resonance with the wave. A resonance spectrum is observed by launching SAWs at 0.3-0.8ω ci . Both the magnitude and frequency dependence of the beam-spreading are in agreement with the theoretical prediction using a Monte Carlo Lorentz code that launches fast ions with an initial spread in real/velocity space and random phases relative to the wave. Measured wave magnetic field data are used in the simulation.

Pulsed-wave tissue Doppler and color tissue Doppler echocardiography: calibration with M-mode, agreement, and reproducibility in a clinical setting

DEFF Research Database (Denmark)

Olsen, Niels Thue; Jons, Christian; Fritz-Hansen, Thomas

2009-01-01

BACKGROUND: Myocardial velocities can be measured with both pulsed-wave tissue Doppler (PWTD) and color tissue Doppler (CTD) echocardiography. We aimed to (A) to explore which of the two methods better approximates true tissue motion and (B) to examine the agreement and the reproducibility...... of the two methods in a routine clinical setting. METHODS: For Study A, the displacements of 63 basal myocardial segments from 13 patients were examined with M-mode and compared with the velocity-time integral of PWTD and CTD velocities. For Study B, the basal lateral segments from 58 patients were examined...... with PWTD and CTD, and the peak myocardial velocities during systole (Sm), early diastole (Em), and late diastole (Am) were measured. RESULTS: Study A: CTD-based measurements of displacement were 12% lower than M-mode measurements (95% CI: -18%; -6%). PWTD velocity-time integrals measured at the outer edge...

The Transcranial Doppler Sonography for Optimal Monitoring and Optimization of Cerebral Perfusion in Aortic Arch Surgery: A Case Series.

Science.gov (United States)

Ghazy, Tamer; Darwisch, Ayham; Schmidt, Torsten; Nguyen, Phong; Elmihy, Sohaila; Fajfrova, Zuzana; Zickmüller, Claudia; Matschke, Klaus; Kappert, Utz

2017-06-16

To analyze the feasibility and advantages of transcranial doppler sonography (TCD) for monitoring and optimization of selective cerebral perfusion (SCP) in aortic arch surgery. From April 2013 to April 2014, nine patients with extensive aortic pathology underwent surgery under moderate hypothermic cardiac arrest with unilateral antegrade SCP under TCD monitoring in our institution. Adequate sonographic window and visualization of circle of Willis were to be confirmed. Intraoperatively, a cerebral cross-filling of the contralateral cerebral arteries on the unilateral SCP was to be confirmed with TCD. If no cross-filling was confirmed, an optimization of the SCP was performed via increasing cerebral flow and increasing PCO2. If not successful, the SCP was to be switched to bilateral perfusion. Air bubble hits were recorded at the termination of SCP. A sonographic window was confirmed in all patients. Procedural success was 100%. The mean operative time was 298 ± 89 minutes. Adequate cross-filling was confirmed in 8 patients. In 1 patient, inadequate cross-filling was detected by TCD and an optimization of cerebral flow was necessary, which was successfully confirmed by TCD. There was no conversion to bilateral perfusion. Extensive air bubble hits were confirmed in 1 patient, who suffered a postoperative stroke. The 30-day mortality rate was 0. Conclusion: The TCD is feasible for cerebral perfusion monitoring in aortic surgery. It enables a confirmation of adequacy of cerebral perfusion strategy or the need for its optimization. Documentation of calcific or air-bubble hits might add insight into patients suffering postoperative neurological deficits.

Development of the doppler electron velocimeter: theory.

Energy Technology Data Exchange (ETDEWEB)

Reu, Phillip L.

2007-03-01

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.

Comparisons between PW Doppler system and enhanced FM Doppler system

DEFF Research Database (Denmark)

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

1995-01-01

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...

Relationship between colour flow Doppler sonographic assessment of corpus luteum activity and progesterone concentrations in mares after embryo transfer

NARCIS (Netherlands)

Brogan, P. T.; Henning, H.; Stout, T. A E; de Ruijter-Villani, M.

2016-01-01

Colour-flow Doppler sonography has been described as a means of assessing corpus luteum (CL) function rapidly, because area of luteal blood vessels correlates well with circulating progesterone (P4) concentrations [P4] in oestrous cycling mares. The aim of this study was to assess the relationships

Diagnostic evaluation of uterine artery Doppler sonography for the prediction of adverse pregnancy outcomes

Directory of Open Access Journals (Sweden)

Mojgan Barati

2014-01-01

Full Text Available Background : Increased impedance to flow in the uterine arteries assessed by value of the Doppler is associated with adverse pregnancy outcomes, especially pre-eclampsia. We investigated the predictive value of a uterine artery Doppler in the identification of adverse pregnancy outcomes such as ′pre-eclampsia′ and ′small fetus for gestational age′ (SGA. Materials and Methods: Three hundred and seventy-nine women, with singleton pregnancy, between 18 and 40 years of age, without risk factors, randomly underwent Doppler interrogation of the uterine arteries, between 16-22 weeks of gestation. Those who had a mean pulsatility index (PI of >1.45 were considered to have an abnormal result, and were evaluated and compared with those who had normal results for adverse pregnancy outcomes, including pre-eclampsia and small for gestational age. The relationship between the variables was assessed with the use of the chi-square test. Results : There were 17 cases (4.5% of abnormal uterine artery Doppler results and 15 of them (88.2% developed pre-eclampsia and four cases (23.5% had neonates small for gestational age. For predicting pre-eclampsia, the mean uterine artery PI had to be >1.45, had to have a specificity of 95.5% (95% CI, 70-92%, a sensitivity of 79% (95% CI, 43-82%, a negative predictive value (NPV of 98.9% (95% CI, 72-96%, and a positive predictive value (PPV of 88.2% (95% CI, 68-98%. In the case of ′small for gestational age′ it had to have a specificity of 96.5% (95% CI, 42-68%, a sensitivity of 57% (95% CI, 53-76%, an NPV of 99.2% (95% CI, 70-92%, and a PPV of 23.5% (95% CI, 30-72%. Conclusion : Uterine artery Doppler evaluation at 16-22 weeks of gestation might be an appropriate tool for identifying pregnancies that may be at an increased risk for development of pre-eclampsia and small fetus for gestational age.

Detection and monitoring of cerebral hemodynamic disturbances with transcranial color-coded duplex sonography in patients after head injury

International Nuclear Information System (INIS)

Kochanowicz, J.; Mariak, Z.; Lyson, T.; Lewko, J.; Krejza, J.; Bilello, M.

2006-01-01

Reduced cerebral blood flow after severe head injury results in an increased risk of ischemic brain damage. Blood flow should therefore be monitored with a simple, reliable method. Transcranial color-coded Doppler sonography (TCCS) is an accepted tool for the diagnosis of cerebral vasospasm; however, its usefulness in evaluating patients with head injury has not been proven. Cerebral blood-flow velocity in the middle, anterior, and posterior cerebral arteries was measured with a 2.5 MHz probe (Aplio SSA 770A, Toshiba, Japan) in 36 subjects with moderate or severe head injury. Serial measurements of resistance index (RI), peak-systolic, end-diastolic, and mean velocity in the middle cerebral arteries were performed 2-24 h after head trauma and in the subsequent days during hospitalization. Immediately after head trauma, increased RI values, and unusually decreased blood-flow velocity (mainly in MCA) were observed. Microcirculation disturbances were suspected because the end-diastolic velocity had substantially diminished. Changes in blood-flow parameters correlated with the clinical state, and in most cases, a poor prognosis. In some patients, blood-flow velocity increased above the normal reference limit and this implied poor prognosis. Transcranial color-coded Doppler sonography is a reliable, repeatable, and accessible tool that provides information about cerebral blood-flow disturbances and may hold diagnostic and prognostic importance. (orig.)

Quantum Interference between Autonomous Single-Photon Sources from Doppler-Broadened Atomic Ensemble

OpenAIRE

Jeong, Teak; Lee, Yoon-Seok; Park, Jiho; Kim, Heonoh; Moon, Han Seb

2017-01-01

To realize a quantum network based on quantum entanglement swapping, bright and completely autonomous sources are essentially required. Here, we experimentally demonstrate Hong-Ou-Mandel (HOM) quantum interference between two independent bright photon pairs generated via the spontaneous four-wave mixing in Doppler-broadened ladder-type 87Rb atoms. Bright autonomous heralded single photons are operated in a continuous-wave (CW) mode with no synchronization or supplemental filters. The four-fol...

Muscle sonography in six patients with hereditary inclusion body myopathy

International Nuclear Information System (INIS)

Adler, Ronald S.; Garolfalo, Giovanna; Paget, Stephen; Kagen, Lawrence

2008-01-01

To evaluate the morphological changes of muscle with sonography in six patients affected by hereditary inclusion body myopathy (HIBM). We studied a group of six Persian Jews diagnosed with HIBM. All were homozygous for the GNE mutation M712T. Ultrasonographic examinations of the quadriceps femoris and hamstring muscle groups were performed. A follow-up ultrasound examination was performed, after an interval of 3 years, in four of these patients. Muscles were assessed subjectively as to echogenicity, determined by gray-scale assessment, and loss of normal muscle morphology. Power Doppler sonography (PDS) was used to assess vascularity. A sonographic finding of central atrophy and peripheral sparing resulting in a target-like appearance was noted in the hamstring compartment of all six patients. The quadriceps compartment also showed involvement of the rectus femoris of all patients, which, in some cases, was the only muscle involved in the quadriceps. Vascularity was markedly reduced in the affected areas, with blood flow demonstrated in the peripherally spared areas. The severity of atrophy increased with disease duration. In this case series, we describe a new sonographic finding as well as document progression of HIBM disease, which has generally been described as quadriceps sparing. The myopathic target lesion, as well as isolated rectus femoris atrophy, may provide a useful adjunct to disease diagnosis. (orig.)

Perforated pyloroduodenal peptic ulcer and sonography.

Science.gov (United States)

Kuzmich, Siarhei; Harvey, Chris J; Fascia, Daniel T M; Kuzmich, Tatsiana; Neriman, Deena; Basit, Rizwan; Tan, Kai Lee

2012-11-01

The purpose of this article is to illustrate the spectrum of sonographic findings in perforated pyloroduodenal peptic ulcer and discuss the potential role of sonography in the diagnosis. Although sonography is not the first-line investigation of choice in suspected perforated peptic ulcer, understanding of the characteristic appearances seen during general abdominal sonography may aid the reader in the diagnosis of this important and sometimes overlooked cause of nonspecific abdominal pain. This may shorten time to the diagnosis and ultimate surgical management.

Brain sonography in African infants with complicated sporadic ...

African Journals Online (AJOL)

Background: To determine the structural findings in brain sonography of African infants with complicated sporadic bacterial meningitis. Materials and Methods: Retrospective assessment of medical records of patients who underwent brain sonography on account of complicated bacterial meningitis. The brain sonography ...

Microembolus Detection by Transcranial Doppler Sonography: Review of the Literature

Directory of Open Access Journals (Sweden)

Vlasta Vuković-Cvetković

2012-01-01

Full Text Available Transcranial Doppler can detect microembolic signals which are characterized by unidirectional high intensity increase, short duration, random occurrence, and a “whistling” sound. Microembolic signals have been detected in a number of clinical settings: carotid artery stenosis, aortic arch plaques, atrial fibrillation, myocardial infarction, prosthetic heart valves, patent foramen ovale, valvular stenosis, during invasive procedures (angiography, percutaneous transluminal angioplasty, surgery (carotid, cardiopulmonary bypass, orthopedic, and in certain systemic diseases. Microembolic signals are frequent in large artery disease, less commonly detected in cardioembolic stroke, and infrequent in lacunar stroke. This article provides an overview about the current state of technical and clinical aspects of microembolus detection.

Optoheterodyne Doppler measurements of the ballistic expansion of the products of the shock wave-induced surface destruction: Experiment and theory

International Nuclear Information System (INIS)

Andriyash, A. V.; Astashkin, M. V.; Baranov, V. K.; Golubinskii, A. G.; Irinichev, D. A.; Kondrat’ev, A. N.; Kuratov, S. E.; Mazanov, V. A.; Rogozkin, D. B.; Stepushkin, S. N.; Khatunkin, V. Yu.

2016-01-01

The results of optoheterodyne Doppler measurements of the ballistic expansion of the products of surface destruction under shock-wave loading are presented. The possibility of determining the physical characteristics of a rapidly flying dust cloud, including the microparticle velocities, the microparticle sizes, and the areal density of the dust cloud, is shown. A compact stand for performing experiments on shock-wave loading of metallic samples is described. Shock-wave loading is performed by a 100-µm-thick tantalum flyer plate accelerated to a velocity of 2.8 km/s. As the samples, lead plates having various thicknesses and the same surface roughness are used. At a shock-wave pressure of 31.5 GPa, the destruction products are solid microparticles about 50 µm in size. At a pressure of 42 and 88 GPa, a liquid-drop dust cloud with a particle size of 10–15 µm is formed. To interpret the spectral data on the optoheterodyne Doppler measurements of the expansion of the surface destruction products (spalled fragments, dust microparticles), a transport equation for the function of mutual coherence of a multiply scattered field is used. The Doppler spectra of a backscattered signal are calculated with the model developed for the dust cloud that appears when a shock wave reaches the sample surface at the parameters that are typical of an experimental situation. Qualitative changes are found in the spectra, depending on the optical thickness of the dust cloud. The obtained theoretical results are in agreement with the experimental data.

Optoheterodyne Doppler measurements of the ballistic expansion of the products of the shock wave-induced surface destruction: Experiment and theory

Energy Technology Data Exchange (ETDEWEB)

Andriyash, A. V. [All-Russia Research Institute of Automatics (Russian Federation); Astashkin, M. V.; Baranov, V. K.; Golubinskii, A. G.; Irinichev, D. A. [Russian Federal Nuclear Center, All-Russia Research Institute of Experimental Physics (VNIIEF) (Russian Federation); Kondrat’ev, A. N., E-mail: an.kondratev@physics.msu.ru; Kuratov, S. E. [All-Russia Research Institute of Automatics (Russian Federation); Mazanov, V. A. [Russian Federal Nuclear Center, All-Russia Research Institute of Experimental Physics (VNIIEF) (Russian Federation); Rogozkin, D. B. [All-Russia Research Institute of Automatics (Russian Federation); Stepushkin, S. N.; Khatunkin, V. Yu. [Russian Federal Nuclear Center, All-Russia Research Institute of Experimental Physics (VNIIEF) (Russian Federation)

2016-06-15

The results of optoheterodyne Doppler measurements of the ballistic expansion of the products of surface destruction under shock-wave loading are presented. The possibility of determining the physical characteristics of a rapidly flying dust cloud, including the microparticle velocities, the microparticle sizes, and the areal density of the dust cloud, is shown. A compact stand for performing experiments on shock-wave loading of metallic samples is described. Shock-wave loading is performed by a 100-µm-thick tantalum flyer plate accelerated to a velocity of 2.8 km/s. As the samples, lead plates having various thicknesses and the same surface roughness are used. At a shock-wave pressure of 31.5 GPa, the destruction products are solid microparticles about 50 µm in size. At a pressure of 42 and 88 GPa, a liquid-drop dust cloud with a particle size of 10–15 µm is formed. To interpret the spectral data on the optoheterodyne Doppler measurements of the expansion of the surface destruction products (spalled fragments, dust microparticles), a transport equation for the function of mutual coherence of a multiply scattered field is used. The Doppler spectra of a backscattered signal are calculated with the model developed for the dust cloud that appears when a shock wave reaches the sample surface at the parameters that are typical of an experimental situation. Qualitative changes are found in the spectra, depending on the optical thickness of the dust cloud. The obtained theoretical results are in agreement with the experimental data.

Mesospheric gravity wave momentum flux estimation using hybrid Doppler interferometry

Directory of Open Access Journals (Sweden)

A. J. Spargo

2017-06-01

Full Text Available Mesospheric gravity wave (GW momentum flux estimates using data from multibeam Buckland Park MF radar (34.6° S, 138.5° E experiments (conducted from July 1997 to June 1998 are presented. On transmission, five Doppler beams were symmetrically steered about the zenith (one zenith beam and four off-zenith beams in the cardinal directions. The received beams were analysed with hybrid Doppler interferometry (HDI (Holdsworth and Reid, 1998, principally to determine the radial velocities of the effective scattering centres illuminated by the radar. The methodology of Thorsen et al. (1997, later re-introduced by Hocking (2005 and since extensively applied to meteor radar returns, was used to estimate components of Reynolds stress due to propagating GWs and/or turbulence in the radar resolution volume. Physically reasonable momentum flux estimates are derived from the Reynolds stress components, which are also verified using a simple radar model incorporating GW-induced wind perturbations. On the basis of these results, we recommend the intercomparison of momentum flux estimates between co-located meteor radars and vertical-beam interferometric MF radars. It is envisaged that such intercomparisons will assist with the clarification of recent concerns (e.g. Vincent et al., 2010 of the accuracy of the meteor radar technique.

Mesospheric gravity wave momentum flux estimation using hybrid Doppler interferometry

Science.gov (United States)

Spargo, Andrew J.; Reid, Iain M.; MacKinnon, Andrew D.; Holdsworth, David A.

2017-06-01

Mesospheric gravity wave (GW) momentum flux estimates using data from multibeam Buckland Park MF radar (34.6° S, 138.5° E) experiments (conducted from July 1997 to June 1998) are presented. On transmission, five Doppler beams were symmetrically steered about the zenith (one zenith beam and four off-zenith beams in the cardinal directions). The received beams were analysed with hybrid Doppler interferometry (HDI) (Holdsworth and Reid, 1998), principally to determine the radial velocities of the effective scattering centres illuminated by the radar. The methodology of Thorsen et al. (1997), later re-introduced by Hocking (2005) and since extensively applied to meteor radar returns, was used to estimate components of Reynolds stress due to propagating GWs and/or turbulence in the radar resolution volume. Physically reasonable momentum flux estimates are derived from the Reynolds stress components, which are also verified using a simple radar model incorporating GW-induced wind perturbations. On the basis of these results, we recommend the intercomparison of momentum flux estimates between co-located meteor radars and vertical-beam interferometric MF radars. It is envisaged that such intercomparisons will assist with the clarification of recent concerns (e.g. Vincent et al., 2010) of the accuracy of the meteor radar technique.

A coordinated study of 1 h mesoscale gravity waves propagating from Logan to Boulder with CRRL Na Doppler lidars and temperature mapper

Science.gov (United States)

Lu, Xian; Chen, Cao; Huang, Wentao; Smith, John A.; Chu, Xinzhao; Yuan, Tao; Pautet, Pierre-Dominique; Taylor, Mike J.; Gong, Jie; Cullens, Chihoko Y.

2015-10-01

We present the first coordinated study using two lidars at two separate locations to characterize a 1 h mesoscale gravity wave event in the mesopause region. The simultaneous observations were made with the Student Training and Atmospheric Research (STAR) Na Doppler lidar at Boulder, CO, and the Utah State University Na Doppler lidar and temperature mapper at Logan, UT, on 27 November 2013. The high precision possessed by the STAR lidar enabled these waves to be detected in vertical wind. The mean wave amplitudes are ~0.44 m/s in vertical wind and ~1% in relative temperature at altitudes of 82-107 km. Those in the zonal and meridional winds are 6.1 and 5.2 m/s averaged from 84 to 99 km. The horizontal and vertical wavelengths inferred from the mapper and lidars are ~219 ± 4 and 16.0 ± 0.3 km, respectively. The intrinsic period is ~1.3 h for the airglow layer, Doppler shifted by a mean wind of ~17 m/s. The wave packet propagates from Logan to Boulder with an azimuth angle of ~135° clockwise from north and an elevation angle of ~ 3° from the horizon. The observed phase difference between the two locations can be explained by the traveling time of the 1 h wave from Logan to Boulder, which is about ~2.4 h. The wave polarization relations are examined through the simultaneous quantifications of the three wind components and temperature. This study has developed a systematic methodology for fully characterizing mesoscale gravity waves, inspecting their intrinsic properties and validating the derivation of horizontal wave structures by applying multiple instruments from coordinated stations.

High-frequency dual mode pulsed wave Doppler imaging for monitoring the functional regeneration of adult zebrafish hearts

Science.gov (United States)

Kang, Bong Jin; Park, Jinhyoung; Kim, Jieun; Kim, Hyung Ham; Lee, Changyang; Hwang, Jae Youn; Lien, Ching-Ling; Shung, K. Kirk

2015-01-01

Adult zebrafish is a well-known small animal model for studying heart regeneration. Although the regeneration of scars made by resecting the ventricular apex has been visualized with histological methods, there is no adequate imaging tool for tracking the functional recovery of the damaged heart. For this reason, high-frequency Doppler echocardiography using dual mode pulsed wave Doppler, which provides both tissue Doppler (TD) and Doppler flow in a same cardiac cycle, is developed with a 30 MHz high-frequency array ultrasound imaging system. Phantom studies show that the Doppler flow mode of the dual mode is capable of measuring the flow velocity from 0.1 to 15 cm s−1 with high accuracy (p-value = 0.974 > 0.05). In the in vivo study of zebrafish, both TD and Doppler flow signals were simultaneously obtained from the zebrafish heart for the first time, and the synchronized valve motions with the blood flow signals were identified. In the longitudinal study on the zebrafish heart regeneration, the parameters for diagnosing the diastolic dysfunction, for example, E/Em < 10, E/A < 0.14 for wild-type zebrafish, were measured, and the type of diastolic dysfunction caused by the amputation was found to be similar to the restrictive filling. The diastolic function was fully recovered within four weeks post-amputation. PMID:25505135

Design And Analysis Of Doppler Radar-Based Vehicle Speed Detection

Directory of Open Access Journals (Sweden)

Su Myat Paing

2015-08-01

Full Text Available The most unwanted thing to happen to a road user is road accident. Most of the fatal accidents occur due to over speeding. Faster vehicles are more prone to accident than the slower one. Among the various methods for detecting speed of the vehicle object detection systems based on Radar have been replaced for about a century for various purposes like detection of aircrafts spacecraft ships navigation reading weather formations and terrain mapping. The essential feature in adaptive vehicle activated sign systems is the accurate measurement of a vehicles velocity. The velocities of the vehicles are acquired from a continuous wave Doppler radar. A very low amount of power is consumed in this system and only batteries can use to operate. The system works on the principle of Doppler Effect by detecting the Doppler shift in microwaves reflected from a moving object. Since the output of the sensor is sinusoidal wave with very small amplitude and needs to be amplified with the help of the amplifier before further processing. The purpose to calculate and display the speed on LCD is performed by the microcontroller.

On the use of horizontal acoustic doppler profilers for continuous bed shear stress monitoring

NARCIS (Netherlands)

Vermeulen, B.; Hoitink, A.J.F.; Sassi, M.G.

2013-01-01

Continuous monitoring of bed shear stress in large river systems may serve to better estimate alluvial sediment transport to the coastal ocean. Here we explore the possibility of using a horizontally deployed acoustic Doppler current profiler (ADCP) to monitor bed shear stress, applying a prescribed

[Pilot study of echocardiographic studies using color- and pulsed-wave spectral Doppler methods in blue-crowned amazons (Amazona ventralis) and blue-fronted amazons (Amazona a. aestiva)].

Science.gov (United States)

Pees, M; Straub, J; Schumacher, J; Gompf, R; Krautwald-Junghanns, M E

2005-02-01

Colour-flow and pulsed-wave spectral Doppler echocardiography was performed on 6 healthy, adult Hispaniolan amazon parrots (Amazona ventralis) and 6 blue-fronted amazon parrots (Amazona a. aestiva) to establish normal reference values. Birds were anesthetized with isoflurane in oxygen and placed in dorsal recumbency. An electrocardiogram was recorded continuously and birds were imaged with a micro-phased-array scanner with a frequency of 7.0 MHz. After assessment of cardiac function in 2-D-echocardiography, blood flow across the left and the right atrioventricular valve and across the aortic valve was determined using color-flow and pulsed-wave spectral Doppler echocardiography. Diastolic inflow (mean value +/- standard deviation) into the left ventricle was 0.17 +/- 0.02 m/s (Hispaniolan amazons) and 0.18 +/- 0.03 m/s (Blue fronted amazons). Diastolic inflow into the right ventricle was 0.22 +/- 0.05 m/s (Hispaniolan amazons) and 0.22 +/- 0.04 m/s (Blue fronted amazons). Velocity across the aortic valve was 0.84 +/- 0.07 m/s (Hispaniolan amazons) and 0.83 +/- 0.08 m/s (Blue fronted amazons). Systolic pulmonary flow could not be detected in any of the birds in this study. No significant differences were evident between the two species examined. Results of this study indicate that Doppler echocardiography is a promising technique to determine blood flow in the avian heart. Further studies in other avian species are needed to establish reference values for assessment of cardiac function in diseased birds.

Diagnostic value of color doppler ultrasonography in detecting stenosis and occlusion of central veins in patients with chronic kidney disease

Directory of Open Access Journals (Sweden)

Masoud Pezeshki Rad

2015-01-01

Full Text Available Venography is an invasive diagnostic test that uses contrast material that provides a picture of the condition of the veins. But, complications, including adverse effects on the kidney, do occur. On the other hand, with the current technological development, application of ultrasound in the diagnosis of obstructive diseases of the veins is gaining popularity, being non-invasive, easy to perform and cost-effective. The aim of this study was to evaluate the diagnostic value of Doppler sonography in the diagnosis of central vein stenosis. In this descriptive-analytical study, 41 hemodialysis patients who had been referred for 50 upper limb venographies to the radiology department of Imam Reza (AS were included. Patients with chronic kidney disease with a history of catheterization of the vein, jugular or subclavian, and who had established fistulas or synthetic vascular grafts were targeted. Central venous ultrasound was performed on both sides to evaluate stenosis or occlusion. Venography was performed by the radiologist the next day or the day before hemodialysis. Data on demographic characteristics, findings of clinical examination and findings of ultrasound as well as venography were recorded by using the SPSS software, Chi-square test and Spearman correlation, and Kappa agreement was calculated for sensitivity, specificity and predictive values. Twenty-three (56% patients were male subjects and 18 patients (44% were female. Twenty-three (56% patients of the study population were aged 60 years. The overall sensitivity, specificity and positive predictive value and negative predictive value of Doppler sonography in the proximal veins in hemodialysis patients compared with venography were, respectively, 80.9%, 79.3%, 73.9% and 85.1%. Color Doppler sonography, as a non-invasive method, could be a good alternative for venography in the assessment of the upper limb with central vein stenosis and occlusion.

Diagnostic value of color doppler ultrasonography in detecting stenosis and occlusion of central veins in patients with chronic kidney disease.

Science.gov (United States)

Rad, Masoud Pezeshki; Kazemzadeh, Gholam Hosain; Ziaee, Masood; Azarkar, Ghodsieh

2015-03-01

Venography is an invasive diagnostic test that uses contrast material that provides a picture of the condition of the veins. But, complications, including adverse effects on the kidney, do occur. On the other hand, with the current technological development, application of ultrasound in the diagnosis of obstructive diseases of the veins is gaining popularity, being non-invasive, easy to perform and cost-effective. The aim of this study was to evaluate the diagnostic value of Doppler sonography in the diagnosis of central vein stenosis. In this descriptive-analytical study, 41 hemodialysis patients who had been referred for 50 upper limb venographies to the radiology department of Imam Reza (AS) were included. Patients with chronic kidney disease with a history of catheterization of the vein, jugular or subclavian, and who had established fistulas or synthetic vascular grafts were targeted. Central venous ultrasound was performed on both sides to evaluate stenosis or occlusion. Venography was performed by the radiologist the next day or the day before hemodialysis. Data on demographic characteristics, findings of clinical examination and findings of ultrasound as well as venography were recorded by using the SPSS software, Chi-square test and Spearman correlation, and Kappa agreement was calculated for sensitivity, specificity and predictive values. Twenty-three (56%) patients were male subjects and 18 patients (44%) were female. Twenty-three (56%) patients of the study population were aged 60 years. The overall sensitivity, specificity and positive predictive value and negative predictive value of Doppler sonography in the proximal veins in hemodialysis patients compared with venography were, respectively, 80.9%, 79.3%, 73.9% and 85.1%. Color Doppler sonography, as a non-invasive method, could be a good alternative for venography in the assessment of the upper limb with central vein stenosis and occlusion.

Power Doppler Ultrasonography and Shear Wave Elastography as Complementary Imaging Methods for Suspected Local Breast Cancer Recurrence.

Science.gov (United States)

Jales, Rodrigo Menezes; Dória, Maira Teixeira; Serra, Kátia Piton; Miranda, Mila Meneguelli; Menossi, Carlos Alberto; Schumacher, Klaus; Sarian, Luis Otávio

2018-06-01

To prospectively investigate the diagnostic accuracy and clinical consequences of power Doppler morphologic criteria and shear wave elastography (SWE) as complementary imaging methods for evaluation of suspected local breast cancer recurrence in the ipsilateral breast or chest wall. Thirty-two breast masses with a suspicion of local breast cancer recurrence on B-mode ultrasonography underwent complementary power Doppler and SWE evaluations. Power Doppler morphologic criteria were classified as avascular, hypovascular, or hypervascular. Shear wave elastography was classified according to a 5-point scale (SWE score) and SWE maximum elasticity. Diagnostic accuracy was assessed by the sensitivity, specificity, and area under the curve. A decision curve analysis assessed clinical consequences of each method. The reference standard for diagnosis was defined as core needle or excisional biopsy. Histopathologic examinations revealed 9 (28.2%) benign and 23 (71.8%) malignant cases. Power Doppler ultrasonography (US) had sensitivity of 34.8% (95% confidence interval [CI], 6.6%-62.9%) and specificity of 45.4% (95% CI, 19.3%-71.5%). The SWE score (≥3) had sensitivity of 87.0% (95% CI, 66.4%-97.2%) and specificity of 44.4% (95% CI, 13.7%-78.8%). The SWE maximum elasticity (velocity > 6.5cm/s) had sensitivity of 87% (95% CI, 66.4%-97.2%) and specificity of 77.8% (95% CI, 40.0% to 97.2%). The areas under the curves for the SWE score and SWE maximum elasticity were 0.71 (95% CI, 0.53-0.87) and 0.82 (95% CI, 0.64-0.93), respectively (P = .32). Power Doppler US is unsuitable for discrimination between local breast cancer recurrence and fibrosis. Although the SWE score and SWE maximum elasticity can make this discrimination, the use of these methods to determine biopsy may lead to poorer clinical outcomes than the current practice of performing biopsies of all suspicious masses. © 2017 by the American Institute of Ultrasound in Medicine.

Use of chest sonography in acute-care radiology☆

Science.gov (United States)

De Luca, C.; Valentino, M.; Rimondi, M.R.; Branchini, M.; Baleni, M. Casadio; Barozzi, L.

2008-01-01

Diagnosis of acute lung disease is a daily challenge for radiologists working in acute-care areas. It is generally based on the results of chest radiography performed under technically unfavorable conditions. Computed tomography (CT) is undoubtedly more accurate in these cases, but it cannot always be performed on critically ill patients who need continuous care. The use of thoracic ultrasonography (US) has recently been proposed for the study of acute lung disease. It can be carried out rapidly at the bedside and does not require any particularly sophisticated equipment. This report analyzes our experience with chest sonography as a supplement to chest radiography in an Emergency Radiology Unit. We performed chest sonography – as an adjunct to chest radiography – on 168 patients with acute chest pathology. Static and dynamic US signs were analyzed in light of radiographic findings and, when possible, CT. The use of chest US improved the authors' ability to provide confident diagnoses of acute disease of the chest and lungs. PMID:23397048

Field test of an all-semiconductor laser-based coherent continuous-wave Doppler lidar for wind energy applications

DEFF Research Database (Denmark)

Sjöholm, Mikael; Dellwik, Ebba; Hu, Qi

-produced all-semiconductor laser. The instrument is a coherent continuous-wave lidar with two fixed-focus telescopes for launching laser beams in two different directions. The alternation between the telescopes is achieved by a novel switching technique without any moving parts. Here, we report results from...... signal strength from external atmospheric parameters such as relative humidity and concentrations of atmospheric particles is discussed. This novel lidar instrument design seems to offer a promising low-cost alternative for prevision remote sensing of wind turbine inflow....

Continuous measurements of discharge from a horizontal acoustic Doppler current profiler in a tidal river

NARCIS (Netherlands)

Hoitink, A.J.F.; Buschman, F.A.; Vermeulen, B.

2009-01-01

Acoustic Doppler current profilers (ADCPs) can be mounted horizontally at a river bank, yielding single-depth horizontal array observations of velocity across the river. This paper presents a semideterministic, semistochastic method to obtain continuous measurements of discharge from horizontal ADCP

Not all ultrasounds are created equal: general sonography versus musculoskeletal sonography in the detection of rotator cuff tears

Science.gov (United States)

Cole, Brandi; Twibill, Kristen; Lam, Patrick; Hackett, Lisa

2016-01-01

Background This cross-sectional analytic diagnostic accuracy study was designed to compare the accuracy of ultrasound performed by general sonographers in local radiology practices with ultrasound performed by an experienced musculoskeletal sonographer for the detection of rotator cuff tears. Methods In total, 238 patients undergoing arthroscopy who had previously had an ultrasound performed by both a general sonographer and a specialist musculoskeletal sonographer made up the study cohort. Accuracy of diagnosis was compared with the findings at arthroscopy. Results When analyzed as all tears versus no tears, musculoskeletal sonography had an accuracy of 97%, a sensitivity of 97% and a specificity of 95%, whereas general sonography had an accuracy of 91%, a sensitivity of 91% and a specificity of 86%. When the partial tears were split with those ≥ 50% thickness in the tear group and those tear group, musculoskeletal sonography had an accuracy of 97%, a sensitivity of 97% and a specificity of 100% and general sonography had an accuracy of 85%, a sensitivity of 84% and a specificity of 87%. Conclusions Ultrasound in the hands of an experienced musculoskeletal sonographer is highly accurate for the diagnosis of rotator cuff tears. General sonography has improved subsequent to earlier studies but remains inferior to an ultrasound performed by a musculoskeletal sonographer. PMID:27660657

The usefulness of contrast-enhanced sonography in the differential diagnostic of adrenal tumors

International Nuclear Information System (INIS)

Slonina, J.; Nienartowicz, E.; Malczewska, J.; Moron, K.; Kumar Agrawal, A.

2006-01-01

Introduction: The occurrence of gland tumors causes significant clinical problem. Non hormone-secreting tumors provide the most complicated diagnostic difficulties. The application of contrast-enhanced sonography could improve the vessels visualization and point out characteristic features of benign and malignant changes. The authors believe that this new method make possible the differential adrenal tumor diagnostic process more precise and increase the specificity of ultrasonography in the recognition of benign and malignant tumors. The aim of this study was to define the usefulness of contrasting agent Levovist in differential diagnostics of adrenal tumors and its influence on sensitivity and specificity of ultrasound examination and to establish patients qualification criteria for surgical procedures. Material and methods: Ultrasound examinations were made with the use of digital devise by GE Voluson 740, probe 4.6 MHz with Doppler options and volumetric probe 3D according to the following protocol: 26 patients with recognized adrenal tumor were qualified for the examination. Patients in the first stage of tumor vascularisation had Doppler examination with color (CD) and power Doppler (PD). Three-dimensional ultrasonography was used to improve visualization of vascularisation. In the final phase of the examination the patients were administrated of Levovist in the recommended by the producer dose: 2,5 g in the concentration of 400 mg/l. Results: 26 cases of adrenal gland tumours were subjected to analysis. In standard ultrasonographic examination focal changes in 25 patients were hipoechogenic focuses and in one case the focus was hyperechogenic. Heterogeneity of focuses was observed in 16 cases. In Doppler examination with color (CD) and power Doppler (PD) vascular blood flow was revealed within 12. After using contrasting agent Levovist vascular blood flow was achieved in 4 additional cases, which constituted 61% . Conclusions: 1. 3D ultrasound could be

21 CFR 872.2050 - Dental sonography device.

Science.gov (United States)

2010-04-01

... § 872.9. (b) Dental sonography device for interpretation and diagnosis—(1) Identification. A dental sonography device for interpretation and diagnosis is an electrically powered device, intended to interpret temporomandibular joint sounds for the diagnosis of temporomandibular joint disorders and associated orofacial pain...

Sonography as an initial study in patients with suspected ureteral stone

International Nuclear Information System (INIS)

Lee, Jae Gue; Lim, Joo Won; Ko, Young Tae; Lee, Dong Ho; Lee, Hye Won; Oh, Joo Hyeong; Yoon, Yup; Lee, Sun Ju

1999-01-01

To evaluate the usefulness of sonography as an initial study in patients with suspected ureteral stone. We have undertaken a prospective study for 106 patients with suspected ureteral stone during 15 months. All the patients subsequently underwent urography at a mean interval of 1.8 days after the abdominopelvic sonography. We had only a clinical impression at the sonography and didn't refer to the other study such as KUB. We observed the degree of hydronephrosis using a grading system by Ellenbogen et aland location and size of stone. Seventy four patients had ureteral stone disease. The sonographic findings of these 74 patients showed a stone with hydronephrosis in 61 patients, a stone without hydronephrosis in 9, only hydronephrosis without stone in 2, and unremarkable finding in 2. In 3 of the remaining 32 patients, sonography showed hydronephrosis without stone. Locations of stone were 9 patients of ureteropelvic junction(UPJ), 19 of proximal ureter, 30 of distal ureter, and 16 of ureterovesical junction(UVJ). The sensitivity of sonography for stone was 95% and the specificity was 100%. When a ureteral stone was present, ipsilateral hydronephrosis was detected in 85% of cases on sonography. When only hydronephrosis without stone was detected on sonography, a ureteral stone was diagnosed in 2(40%) of 5 patients. Mean discrepancy of stone size between sonography and KUB was 3.1mm and stone size on sonography was larger. Grade of hydronephrosis between sonography and urography was the same in 32(59%) of 54 patients, whose stones were not expelled until urography after sonography. Sonography could be used as an initial study in patients with suspected ureteral stone.

A Doppler Radar System for Sensing Physiological Parameters in Walking and Standing Positions

Directory of Open Access Journals (Sweden)

Malikeh Pour Ebrahim

2017-03-01

Full Text Available Doppler radar can be implemented for sensing physiological parameters wirelessly at a distance. Detecting respiration rate, an important human body parameter, is essential in a range of applications like emergency and military healthcare environments, and Doppler radar records actual chest motion. One challenge in using Doppler radar is being able to monitor several patients simultaneously and in different situations like standing, walking, or lying. This paper presents a complete transmitter-receiver Doppler radar system, which uses a 4 GHz continuous wave radar signal transmission and receiving system, to extract base-band data from a phase-shifted signal. This work reports experimental evaluations of the system for one and two subjects in various standing and walking positions. It provides a detailed signal analysis of various breathing rates of these two subjects simultaneously. These results will be useful in future medical monitoring applications.

Doppler Temperature Coefficient Calculations Using Adjoint-Weighted Tallies and Continuous Energy Cross Sections in MCNP6

Science.gov (United States)

Gonzales, Matthew Alejandro

The calculation of the thermal neutron Doppler temperature reactivity feedback co-efficient, a key parameter in the design and safe operation of advanced reactors, using first order perturbation theory in continuous energy Monte Carlo codes is challenging as the continuous energy adjoint flux is not readily available. Traditional approaches of obtaining the adjoint flux attempt to invert the random walk process as well as require data corresponding to all temperatures and their respective temperature derivatives within the system in order to accurately calculate the Doppler temperature feedback. A new method has been developed using adjoint-weighted tallies and On-The-Fly (OTF) generated continuous energy cross sections within the Monte Carlo N-Particle (MCNP6) transport code. The adjoint-weighted tallies are generated during the continuous energy k-eigenvalue Monte Carlo calculation. The weighting is based upon the iterated fission probability interpretation of the adjoint flux, which is the steady state population in a critical nuclear reactor caused by a neutron introduced at that point in phase space. The adjoint-weighted tallies are produced in a forward calculation and do not require an inversion of the random walk. The OTF cross section database uses a high order functional expansion between points on a user-defined energy-temperature mesh in which the coefficients with respect to a polynomial fitting in temperature are stored. The coefficients of the fits are generated before run- time and called upon during the simulation to produce cross sections at any given energy and temperature. The polynomial form of the OTF cross sections allows the possibility of obtaining temperature derivatives of the cross sections on-the-fly. The use of Monte Carlo sampling of adjoint-weighted tallies and the capability of computing derivatives of continuous energy cross sections with respect to temperature are used to calculate the Doppler temperature coefficient in a research

Continuous-scanning laser Doppler vibrometry: Extensions to arbitrary areas, multi-frequency and 3D capture

International Nuclear Information System (INIS)

Weekes, B.; Ewins, D.; Acciavatti, F.

2014-01-01

To date, differing implementations of continuous scan laser Doppler vibrometry have been demonstrated by various academic institutions, but since the scan paths were defined using step or sine functions from function generators, the paths were typically limited to 1D line scans or 2D areas such as raster paths or Lissajous trajectories. The excitation was previously often limited to a single frequency due to the specific signal processing performed to convert the scan data into an ODS. In this paper, a configuration of continuous-scan laser Doppler vibrometry is demonstrated which permits scanning of arbitrary areas, with the benefit of allowing multi-frequency/broadband excitation. Various means of generating scan paths to inspect arbitrary areas are discussed and demonstrated. Further, full 3D vibration capture is demonstrated by the addition of a range-finding facility to the described configuration, and iteratively relocating a single scanning laser head. Here, the range-finding facility was provided by a Microsoft Kinect, an inexpensive piece of consumer electronics

Color Doppler flow mapping of stenotic and regurgitant natural heart valves

International Nuclear Information System (INIS)

Nanda, N.C.

1986-01-01

Color Doppler echocardiography has found widest application in reliable detection and assessment of severity of both atrio-ventricular and semi-lunar valve incompetence. The authors believe both the sensitivity and specificity of color Doppler for the detection of mitral and aortic regurgitation is very high in patients with adequate acoustic windows. In 82 patients with proven mitral regurgitation studied, the best correlations with angiography were noted when the maximum or average regurgitant jet are obtained by color Doppler from three standard 2-D echo planes (parasternal long and short axis and apical four chamber view) and expressed as a percentage of the left atrial area were considered. The criteria the authors used for assessment of tricuspid and pulmonary valve incompetence are similar to those used for mitral and aortic valve incompetence, but the lack of a good ''gold'' standard has hampered validation. The color Doppler technique also supplements conventional Doppler in the assessment of severity of stenotic lesions by facilitating parallel alignment of the continuous wave Doppler cursor line with the stenotic jet for accurate recording of maximal velocities and pressure gradients. The authors have found this method especially useful in the assessment of aortic stenosis. In conclusion, color Doppler flow mapping combined with conventional echocardiography provides, for the first time, a comprehensive noninvasive assessement of the severity of regurgitant and stenotic lesions

Tc-99m DTPA perfusion scintigraphy and color coded duplex sonography in the evaluation of minimal renal allograft perfusion

Energy Technology Data Exchange (ETDEWEB)

Bair, H.J.; Platsch, G.; Wolf, F. [Erlangen-Nuernberg Univ., Erlangen (Germany). Dept. of Nuclear Medicine; Guenter, E.; Becker, D. [Erlangen-Nuernberg Univ., Erlangen (Germany). Dept. of Internal Medicine 1; Rupprecht, H.; Neumayer, H.H. [Erlangen-Nuernberg Univ., Erlangen (Germany). Dept. of Internal Medicine 4

1997-08-01

Aim: The clinical impact of perfusion scintigraphy versus color coded Duplex sonography was evaluated, with respect to their potential in assessing minimal allograft perfusion in vitally threatened kidney transplants, i.e. oligoanuric allografts suspected to have either severe rejection or thrombosis of the renal vein or artery. Methods: From July 1990 to August 1994 the grafts of 15 out of a total of 315 patients were vitally threatened. Technetium-99m DTPA scintigraphy and color coded Duplex sonography were performed in all patients. For scintigraphic evaluation of transplant perfusion analog scans up to 60 min postinjection, and time-activity curves over the first 60 sec after injection of 370-440 MBq Tc-99m diethylenetriaminepentaacetate acid (DTPA) were used and classified by a perfusion score, the time between renal and iliac artery peaks (TDiff) and the washout of the renogram curve. Additionally, evaluation of excretion function and assessment of vascular or urinary leaks were performed. By color coded Duplex sonography the perfusion in all sections of the graft as well as the vascular anastomoses were examined and the maximal blood flow velocity (Vmax) and the resistive index (RI) in the renal artery were determined by means of the pulsed Doppler device. Pathologic-anatomical diagnosis was achieved by either biopsy or post-explant histology in all grafts. Results: Scintigraphy and color coded Duplex sonography could reliably differentiate minimal (8/15) and not perfused (7/15) renal allografts. The results were confirmed either by angiography in digital subtraction technique (DSA) or the clinical follow up. Conclusion: In summary, perfusion scintigraphy and color coded Duplex sonography are comparable modalities to assess kidney graft perfusion. In clinical practice scintigraphy and colorcoded Doppler sonography can replace digital subtraction angiography in the evaluation of minimal allograft perfusion. (orig.) [Deutsch] Ziel der Studie war es, das

Transcranial Duplex Sonography Predicts Outcome following an Intracerebral Hemorrhage.

Science.gov (United States)

Camps-Renom, P; Méndez, J; Granell, E; Casoni, F; Prats-Sánchez, L; Martínez-Domeño, A; Guisado-Alonso, D; Martí-Fàbregas, J; Delgado-Mederos, R

2017-08-01

Several radiologic features such as hematoma volume are related to poor outcome following an intracerebral hemorrhage and can be measured with transcranial duplex sonography. We sought to determine the prognostic value of transcranial duplex sonography in patients with intracerebral hemorrhage. We conducted a prospective study of patients diagnosed with spontaneous intracerebral hemorrhage. Transcranial duplex sonography examinations were performed within 2 hours of baseline CT, and we recorded the following variables: hematoma volume, midline shift, third ventricle and lateral ventricle diameters, and the pulsatility index in both MCAs. We correlated these data with the CT scans and assessed the prognostic value of the transcranial duplex sonography measurements. We assessed early neurologic deterioration during hospitalization and mortality at 1-month follow-up. We included 35 patients with a mean age of 72.2 ± 12.8 years. Median baseline hematoma volume was 9.85 mL (interquartile range, 2.74-68.29 mL). We found good agreement and excellent correlation between transcranial duplex sonography and CT when measuring hematoma volume ( r = 0.791; P duplex sonography measurements showed that hematoma volume was an independent predictor of early neurologic deterioration (OR, 1.078; 95% CI, 1.023-1.135) and mortality (OR, 1.089; 95% CI, 1.020-1.160). A second regression analysis with CT variables also demonstrated that hematoma volume was associated with early neurologic deterioration and mortality. When we compared the rating operation curves of both models, their predictive power was similar. Transcranial duplex sonography showed an excellent correlation with CT in assessing hematoma volume and midline shift in patients with intracerebral hemorrhage. Hematoma volume measured with transcranial duplex sonography was an independent predictor of poor outcome. © 2017 by American Journal of Neuroradiology.

Gastrointestinal tract sonography in fetuses and children

Energy Technology Data Exchange (ETDEWEB)

Couture, Alain; Baud, Catherine; Ferran, Jean Louis; Saguintaah, Magali; Veyrac, Corinne [Hopital Arnaud de Villeneuve, 34 - Montpellier (France). Service de Radiologie Pediatrique

2008-07-01

Sonography of the gastrointestinal tract in fetuses, neonates and children entails no known biological risk, permits serial scanning and can provide information unobtainable with any other imaging modality. In experienced hands it can be used as the initial imaging technique in a number of gastrointestinal diseases and conditions. This book provides a comprehensive account of the current state of the art regarding sonography in this context. An introductory chapter compares the merits of sonography and magnetic resonance imaging of the fetal gastrointestinal tract. Subsequent chapters focus on the technique, pitfalls and findings in a wide variety of applications, including antropyloric diseases, bowel obstruction, bowel wall thickening, colitis, appendicitis, some types of intussusception, abdominal wall and umbilical abnormalities, intraperitoneal tumors, and trauma. In each case the sonographic morphology is considered in depth with the aid of high-quality illustrations. A concluding chapter comprises a quiz based on 15 case reports. Gastrointestinal Tract Sonography in Fetuses and Children will be of value to all with an interest in this field. (orig.)

Transvaginal versus transabdominal sonography in the evaluation of pelvic pathology

International Nuclear Information System (INIS)

Qureshi, I.H.; Ullah, H.; Akram, M.H.; Ashfaq, S.; Nayyar, S.

2004-01-01

Objective: To find the accuracy of sonographic information provided by transvaginal sonography (TVS) in pelvic pathology as compared to transabdominal sonography (TAS). Materials and Methods: Hundred patients were included in the study from a total of 212 referred for pelvic sonography. Two radiologists independently performed transabdominal and transvaginal sonography of these patients. An independent observer compared the findings. TVS was graded as superior, equal or inferior to TAS depending on the score assigned by them. Results: TVS was considered superior in 63%, equal in 27% and inferior in 10% of the cases as compared to transabdominal sonography. It was graded inferior to TAS in cases with large pelvic masses and superior in majority of cases of ovarian follicle monitoring, polycystic ovaries, endometrial carcinoma and suspected ectopic pregnancy. Cases in which both techniques were considered equal included patients with no abnormal finding, some pelvic masses and advanced pelvic inflammatory disease. Conclusion: Transvagival sonography is superior to transabdominal sonography in most cases of pelvic pathology. However, TAS should still be the initial sonographic technique for routine evaluation of the female pelvis followed by TVS if indicated. In cases of ovarian follicle monitoring, suspected polycystic ovaries, endometrial pathology and suspected ectopic pregnancy, TVS may be used as the initial sonographic technique and can even replace TAS. (author)

Applications of doppler effect in navigation and oceanography

Digital Repository Service at National Institute of Oceanography (India)

Joseph, A.

The Doppler effect is the change in frequency of the received sound waves/electromagnetic waves when there is a relative motion between the transmitter and the receiver of these waves. This effect is used for diverse applications in different areas...

Determination of Testicular Blood Flow in Camelids Using Vascular Casting and Color Pulsed-Wave Doppler Ultrasonography

OpenAIRE

Kutzler, Michelle; Tyson, Reid; Grimes, Monica; Timm, Karen

2011-01-01

We describe the vasculature of the camelid testis using plastic casting. We also use color pulsed-wave Doppler ultrasonography to measure testicular blood flow and compare the differences between testicular blood flow in fertile and infertile camelids. The testicular artery originates from the ventral surface of the aorta, gives rise to an epididymal branch, and becomes very tortuous as it approaches the testis. Within the supratesticular arteries, peak systolic velocity (PSV) was higher in f...

Overnight non-contact continuous vital signs monitoring using an intelligent automatic beam-steering Doppler sensor at 2.4 GHz.

Science.gov (United States)

Batchu, S; Narasimhachar, H; Mayeda, J C; Hall, T; Lopez, J; Nguyen, T; Banister, R E; Lie, D Y C

2017-07-01

Doppler-based non-contact vital signs (NCVS) sensors can monitor heart rates, respiration rates, and motions of patients without physically touching them. We have developed a novel single-board Doppler-based phased-array antenna NCVS biosensor system that can perform robust overnight continuous NCVS monitoring with intelligent automatic subject tracking and optimal beam steering algorithms. Our NCVS sensor achieved overnight continuous vital signs monitoring with an impressive heart-rate monitoring accuracy of over 94% (i.e., within ±5 Beats-Per-Minute vs. a reference sensor), analyzed from over 400,000 data points collected during each overnight monitoring period of ~ 6 hours at a distance of 1.75 meters. The data suggests our intelligent phased-array NCVS sensor can be very attractive for continuous monitoring of low-acuity patients.

Focused abdominal sonography for trauma (FAST) in blunt paediatric abdominal trauma

International Nuclear Information System (INIS)

Faruque, A. V.; Qazi, S. H.; Khan, M. A. M.

2013-01-01

Objective: To evaluate the role of focussed abdominal sonography for trauma in blunt paediatric abdominal trauma patients, and to see if the role of computed tomography scan could be limited to only those cases in which sonography was positive. Methods: The retrospective study covered 10 years, from January 1, 2000 to December 31, 2009, and was conducted at the Department of Radiology and Department of Emergency Medicine, Aga Khan University Hospital, Karachi. It comprised cases of 174 children from birth to 14 years who had presented with blunt abdominal trauma and had focussed abdominal sonography for trauma done at the hospital. The findings were correlated with computed tomography scan of the abdomen and clinical follow-up. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of focussed abdominal sonography for trauma were calculated for blunt abdominal trauma. SPSS 17 was used for statistical analysis. Results: Of the total 174 cases, 31 (17.81%) were later confirmed by abdominal scan. Of these 31 children, sonography had been positive in 29 (93.54%) children. In 21 (67.74%) of the 31 children, sonography had been true positive; 8 (25%) (8/31) were false positive; and 2 (6%) (2/31) were false negative. There were 6 (19.3%) children in which sonography was positive and converted to laparotomy. There was no significant difference on account of gender (p>0.356). Focussed abdominal sonography for trauma in the study had sensitivity of 91%, specificity of 95%, positive predictive value of 73%, and negative predictive value of 73% with accuracy of 94%. All patients who had negative sonography were discharged later, and had no complication on clinical follow-up. Conclusions: Focussed abdominal sonography for trauma is a fairly reliable mode to assess blunt abdominal trauma in children. It is a useful tool to pick high-grade solid and hollow viscous injury. The results suggest that the role of computed tomography scan can be

Duplex sonography of the near-surface leg veins

International Nuclear Information System (INIS)

Mendoza, E.

2007-01-01

The book contains the following contributions: The ultrasonograph, selection of the ultrasonic transducer, anatomy of the near-surface vein system, physiology of the near-surface vein system, varicose status classification, systematics of the duplex sonography of near-surface leg veins, provocational maneuver for the duplex sonographic varicose diagnostics, exploration of vena saphena parva, perforans veins, side branches, phlebitis, sonography for varicose therapy, postsurgical sonography, deep leg veins, examination of near-surface leg veins for the pathology of the deep vein system, differential diagnostic clarification of leg oedema from the phlebologic-lymphological view, diagnostic side features along the near-surface leg veins

Toward continuous-wave operation of organic semiconductor lasers

Science.gov (United States)

Sandanayaka, Atula S. D.; Matsushima, Toshinori; Bencheikh, Fatima; Yoshida, Kou; Inoue, Munetomo; Fujihara, Takashi; Goushi, Kenichi; Ribierre, Jean-Charles; Adachi, Chihaya

2017-01-01

The demonstration of continuous-wave lasing from organic semiconductor films is highly desirable for practical applications in the areas of spectroscopy, data communication, and sensing, but it still remains a challenging objective. We report low-threshold surface-emitting organic distributed feedback lasers operating in the quasi–continuous-wave regime at 80 MHz as well as under long-pulse photoexcitation of 30 ms. This outstanding performance was achieved using an organic semiconductor thin film with high optical gain, high photoluminescence quantum yield, and no triplet absorption losses at the lasing wavelength combined with a mixed-order distributed feedback grating to achieve a low lasing threshold. A simple encapsulation technique greatly reduced the laser-induced thermal degradation and suppressed the ablation of the gain medium otherwise taking place under intense continuous-wave photoexcitation. Overall, this study provides evidence that the development of a continuous-wave organic semiconductor laser technology is possible via the engineering of the gain medium and the device architecture. PMID:28508042

Doppler-guided retrograde catheterization system

Science.gov (United States)

Frazin, Leon J.; Vonesh, Michael J.; Chandran, Krishnan B.; Khasho, Fouad; Lanza, George M.; Talano, James V.; McPherson, David D.

1991-05-01

The purpose of this study was to investigate a Doppler guided catheterization system as an adjunctive or alternative methodology to overcome the disadvantages of left heart catheterization and angiography. These disadvantages include the biological effects of radiation and the toxic and volume effects of iodine contrast. Doppler retrograde guidance uses a 20 MHz circular pulsed Doppler crystal incorporated into the tip of a triple lumen multipurpose catheter and is advanced retrogradely using the directional flow information provided by the Doppler waveform. The velocity detection limits are either 1 m/second or 4 m/second depending upon the instrumentation. In a physiologic flow model of the human aortic arch, multiple data points revealed a positive wave form when flow was traveling toward the catheter tip indicating proper alignment for retrograde advancement. There was a negative wave form when flow was traveling away from the catheter tip if the catheter was in a branch or bent upon itself indicating improper catheter tip position for retrograde advancement. In a series of six dogs, the catheter was able to be accurately advanced from the femoral artery to the left ventricular chamber under Doppler signal guidance without the use of x-ray. The potential applications of a Doppler guided retrograde catheterization system include decreasing time requirements and allowing safer catheter guidance in patients with atherosclerotic vascular disease and suspected aortic dissection. The Doppler system may allow left ventricular pressure monitoring in the intensive care unit without the need for x-ray and it may allow left sided contrast echocardiography. With pulse velocity detection limits of 4 m/second, this system may allow catheter direction and passage into the aortic root and left ventricle in patients with aortic stenosis. A modification of the Doppler catheter may include transponder technology which would allow precise catheter tip localization once the

Clinical experience with contrast infusion sonography as an Essure confirmation test.

Science.gov (United States)

Connor, Viviane F

2011-06-01

The purpose of this study was to assess the clinical experience, including the feasibility, safety, compliance, and efficacy, of contrast infusion sonography as an Essure (Conceptus Inc, Mountain View, CA) confirmation test. A retrospective chart review and telephone survey were conducted at an academic multispecialty group. The study participants were women with Essure intervention who underwent contrast infusion sonography, transvaginal sonography, and hysterosalpingography as Essure confirmation tests. The main outcome measures included the feasibility, safety, compliance, and efficacy of contrast infusion sonography as a first-line Essure confirmation test. A total of 118 women had successful bilateral Essure placement. Of the 63 who consented to contrast infusion sonography, 53 (84.1%) had proper bilateral placement and tubal occlusion and were encouraged to rely on Essure. Four were suspected of having unilateral tubal patency; hysterosalpingography in 2 confirmed bilateral tubal occlusion, and 2 were noncompliant with second-line hysterosalpingography. Three patients suspected of having unsatisfactory or uncertain placement on initial transvaginal sonography were encouraged to undergo hysterosalpingography in lieu of contrast infusion sonography, which confirmed unsatisfactory placement in 2 and proper placement and occlusion in 1. Three contrast infusion sonographic procedures could not be completed because of technical issues; therefore, contrast infusion sonography was feasible in 95.2% of the patients (60 of 63). No notable adverse events occurred. Only 17 patients were noncompliant with any confirmation test, yielding an overall compliance rate of 86% (101 of 118). No pregnancies occurred during 669 woman-months of follow-up. The average reimbursement for contrast infusion sonography was US$251.78. Preliminary clinical data suggest that contrast infusion sonography is a feasible, safe, and accurate Essure confirmation test, which is well accepted by

Doppler radar physiological sensing

CERN Document Server

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

2016-01-01

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.

Coherent scattering of CO2 light from ion-acoustic waves

International Nuclear Information System (INIS)

Peratt, A.L.; Watterson, R.L.; Derfler, H.

1977-01-01

Scattering of laser radiation from ion-acoustic waves in a plasma is investigated analytically and experimentally. The formulation predicts a coherent component of the scattered power on a largely incoherent background spectrum when the acoustic analog of Bragg's law and Doppler shift conditions are satisfied. The experiment consists of a hybrid CO 2 laser system capable of either low power continuous wave or high power pulsed mode operation. A heterodyne light mixing scheme is used to detect the scattered power. The proportionality predicted by the theory is verified by scattering from externally excited acoustic and ion-acoustic waves; continuous wave and pulsed modes in each case. Measurement of the ion-acoustic dispersion relation by continuous wave scattering is also presented

Left coronary arterial blood flow: Noninvasive detection by Doppler US

International Nuclear Information System (INIS)

Gramiak, R.; Holen, J.; Moss, A.J.; Gutierrez, O.H.; Picone, A.L.; Roe, S.A.

1986-01-01

Continuous wave (CW) and pulsed Doppler ultrasound studies with spectral analysis were used to detect the left coronary arterial blood flow in patients who were undergoing routine echocardiography. The pulmonary artery is a stable ultrasonic landmark from which detection of the blood flow can be effected. The left coronary artery can be distinguished by its blood flow toward the cardiac apex and by specific, functional flow features. Flow patterns vary among the left main, circumflex, and anterior descending arteries; patterns also vary with respiration cycles. In the present study, coronary arterial blood flow was detected in 58 of 70 patients (83%). Findings were validated by selectively injecting an agitated saline contrast medium into the left coronary artery and, in another study, by comparing human Doppler phasic flow waveforms with electromagnetic flowmeter recordings obtained in dogs

Preliminary simulation study of doppler reflectometry

International Nuclear Information System (INIS)

Ishii, Yuta; Hojo, Hitoshi; Yoshikawa, Masashi; Ichimura, Makoto; Haraguchi, Yusuke; Imai, Tsuyoshi; Mase, Atsushi

2010-01-01

A preliminary simulation study of Doppler reflectometry is performed. The simulations solve Maxwell's equations by a finite difference time domain (FDTD) code method in two dimensions. A moving corrugated metal target is used as a plasma cutoff layer to study the basic features of Doppler reflectometry. We examined the effects of the full width at half maximum (FWHM) of the electromagnetic waves and the corrugation depth of the metal target. Furthermore, the effect of a nonuniform plasma is studied using this FDTD analysis. The Doppler shift and velocity are compared with those obtained from FDTD analysis of a uniform plasma. (author)

(abstract) Spacecraft Doppler Tracking with the Deep Space Network in the Search for Gravitational Waves

Science.gov (United States)

Asmar, Sami; Renzetti, Nicholas

1994-01-01

The Deep Space Network generates accurate radio science data observables for investigators who use radio links between spacecraft and the Earth to examine small changes in the phase and/or amplitude of the signal to study a wide variety of structures and phenomena in space. Several such studies are directed at aspects of the theory of general relativity such as gravitational redshift and gravitational waves. A gravitational wave is a propagating, polarized gravitational field, a ripple in the curvature of space-time. In Einstein's theory of general relativity, the waves are propagating solutions of the Einstein field equations. Their amplitudes are dimensionless strain amplitudes that change the fractional difference in distance between test masses and the rates at which separated clocks keep time. Predicted by all relativistic theories of gravity, they are extremely weak (the ratio of gravitational forces to electrical forces is about 10(sup -40)) and are generated at detectable levels only by astrophysical sources - very massive sources under violent dynamical conditions. The waves have never been detected but searches in the low-frequency band using Doppler tracking of many spacecraft have been conducted and others are being planned. Upper limits have been placed on the gravitational wave strength with the best sensitivities to date are for periodic waves being 7 x 10(sup -15).

Sonography in the diagnosis of acute appendicitis

Directory of Open Access Journals (Sweden)

Ahmad Ryazi

2003-09-01

Full Text Available Graded compressive sonography may be useful as an adjuvant in the diagnosis of acute appendicitis. To determine the role of sonography in the differential diagnosis of acute appendicitis, preappendectomy sonographic data of 164 consecutive cases in Fatemeh-Zahra Teaching Hospital were evaluated. Of 113 (68.9% patients who had acute appendicitis in histopathology, 64 (56.6% cases had preoperative sonographic diagnosis of acute appendicitis. Of 51 patients who had normal appendices, 40 (78.4% cases had normal appendices in sonographic evaluations. Sensitivity, specificity and accuracy of sonography for acute appendicitis were 56.7%, 78.4% and 0.63, respectively. The positive and negative predictive values were 85.3% and 44.49% respectively. As a result, sonographic evaluation is an additional diagnostic tool in acute appendicitis.

Spectral pulsed-wave tissue Doppler imaging lateral-to-septal delay fails to predict clinical or echocardiographic outcome after cardiac resynchronization therapy

NARCIS (Netherlands)

O.I.I. Soliman (Osama Ibrahim Ibrahim); D.A.M.J. Theuns (Dominic); M.L. Geleijnse (Marcel); A. Nemes (Attila); K. Caliskan (Kadir); W.B. Vletter (Wim); L.J.L.M. Jordaens (Luc); F.J. ten Cate (Folkert)

2007-01-01

textabstractAims: The current study sought to assess if pre-implantation lateral-to-septal delay (LSD) ≥60 ms assessed by spectral pulsed-wave myocardial tissue Doppler imaging (PW-TDI) could predict successful long-term outcome after cardiac resynchronization therapy (CRT). Methods and results

Focused abdominal sonography for trauma (FAST) in blunt paediatric abdominal trauma.

Science.gov (United States)

Faruque, Ahmad Vaqas; Qazi, Saqib Hamid; Khan, Muhammad Arif Mateen; Akhtar, Wassem; Majeed, Amina

2013-03-01

To evaluate the role of focussed abdominal sonography for trauma in blunt paediatric abdominal trauma patients, and to see if the role of computed tomography scan could be limited to only those cases in which sonography was positive. The retrospective study covered 10 years, from January 1,2000 to December 31,2009, and was conducted at the Department of Radiology and Department of Emergency Medicine, Aga Khan University Hospital, Karachi. It comprised cases of 174 children from birth to 14 years who had presented with blunt abdominal trauma and had focussed abdominal sonography for trauma done at the hospital. The findings were correlated with computed tomography scan of the abdomen and clinical follow-up. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of focussed abdominal sonography for trauma were calculated for blunt abdominal trauma. SPSS 17 was used for statistical analysis. Of the total 174 cases, 31 (17.81%) were later confirmed by abdominal scan. Of these 31 children, sonography had been positive in 29 (93.54%) children. In 21 (67.74%) of the 31 children, sonograpy had been true positive; 8 (25%) (8/31) were false positive; and 2 (6%) (2/31) were false negative. There were 6 (19.3%) children in which sonography was positive and converted to laparotomy. There was no significant difference on account of gender (p>0.356). Focussed abdominal sonography for trauma in the study had sensitivity of 91%, specificity of 95%, positive predictive value of 73%, and negative predictive value of 73% with accuracy of 94%. All patients who had negative sonography were discharged later, and had no complication on clinical follow-up. Focussed abdominal sonography for trauma is a fairly reliable mode to assess blunt abdominal trauma in children. It is a useful tool to pick high-grade solid and hollow viscous injury. The results suggest that the role of computed tomography scan can be limited to those cases in which focussed

A Wearable Transcranial Doppler Ultrasound Phased Array System.

Science.gov (United States)

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

2018-01-01

 Practical deficiencies related to conventional transcranial Doppler (TCD) sonography have restricted its use and applicability. This work seeks to mitigate several such constraints through the development of a wearable, electronically steered TCD velocimetry system, which enables noninvasive measurement of cerebral blood flow velocity (CBFV) for monitoring applications with limited operator interaction. A highly-compact, discrete prototype system was designed and experimentally validated through flow phantom and preliminary human subject testing. The prototype system incorporates a custom two-dimensional transducer array and multi-channel transceiver electronics, thereby facilitating acoustic beamformation via phased array operation. Electronic steering of acoustic energy enables algorithmic system controls to map Doppler power throughout the tissue volume of interest and localize regions of maximal flow. Multi-focal reception permits dynamic vessel position tracking and simultaneous flow velocimetry over the time-course of monitoring. Experimental flow phantom testing yielded high correlation with concurrent flowmeter recordings across the expected range of physiological flow velocities. Doppler power mapping has been validated in both flow phantom and preliminary human subject testing, resulting in average vessel location mapping times testing. A wearable prototype CBFV measurement system capable of autonomous vessel search and tracking has been presented. Although flow phantom and preliminary human validation show promise, further human subject testing is necessary to compare velocimetry data against existing commercial TCD systems. Additional human subject testing must also verify acceptable vessel search and tracking performance under a variety of subject populations and motion dynamics-such as head movement and ambulation.

Detection of Moving Targets Based on Doppler Spectrum Analysis Technique for Passive Coherent Radar

Directory of Open Access Journals (Sweden)

Zhao Yao-dong

2013-06-01

Full Text Available A novel method of moving targets detection taking Doppler spectrum analysis technique for Passive Coherent Radar (PCR is provided. After dividing the receiving signals into segments as pulse series, it utilizes the technique of pulse compress and Doppler processing to detect and locate the targets. Based on the algorithm for Pulse-Doppler (PD radar, the equipollence between continuous and pulsed wave in match filtering is proved and details of this method are introduced. To compare it with the traditional method of Cross-Ambiguity Function (CAF calculation, the relationship and mathematical modes of them are analyzed, with some suggestions on parameters choosing. With little influence to the gain of targets, the method can greatly promote the processing efficiency. The validity of the proposed method is demonstrated by offline processing real collected data sets and simulation results.

Doppler changes of extracranial cerebral and peripheral arteries in cardiovascular diseases

International Nuclear Information System (INIS)

Dichev, P.

1995-01-01

In recent years Doppler sonography has been approved as a valuable noninvasive method for identification of the extracranial vascular obturations. On the other hand obturational pathology of the extracranial arteries have often been associated with different cardiovascular diseases, and this requires perfect awareness of blood flow changes in the latter. The current study considers the specific flow changes in extracranial cerebral arteries in patients with ischemic heart disease (III-IV) (functional grade - FG - NYHA), and those with concomitant congestive heart failure (III-IV FG), as compared to healthy subjects. In the patients with ischemic heart disease without heart failure the changes are not as significant as compared to healthy subjects (p<0.1). Congestive heart failure is related to significant changes in some of the Doppler parameters. In the last stage of congestive heart failure spectral waveform of the internal carotid arteries also changes. Additionally the changes of spectral waveform of the carotid arteries in different heart diseases are represented: Idiopathic Subvalvular Aortic Stenosis, Valvular Aortic Stenosis and Regurgitation, Supravalvular Aortic Stenosis, Aortic Coarctation, Patent Ductus Botalli, Orthostatismus, Tamponade. Some of the changes are very specific and the Doppler technique would be useful for diagnosis of these diseases. 7 refs., 12 figs. (author)

Correlation of transcranial Doppler ultrasonography with MRI and MRA in the evaluation of sickle cell disease patients with prior stroke

International Nuclear Information System (INIS)

Kogutt, M.S.; Goldwag, S.S.; Gupta, K.L.; Kaneko, K.; Humbert, J.R.

1994-01-01

We prospectively evaluated a group of patients with sickle cell disease and a clinical history of prior stroke, comparing transcranial Doppler sonography (TCD) to both magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) to determine its efficacy for the detection of flow abnormalities associated with prior cerebral infarction. Using MRI as the standard examination, there was 94 % sensitivity and 30 % specificity, and using MRA as the standard examination, there was 91 % sensitivity and 22 % specificity. We concur with other reports that the transcranial Doppler examination is a highly sensitive study. In our group of sickle cell disease patients with prior stroke, TCD reliably detected flow abnormalities that correlated to areas of prior cerebral infarction. (orig.)

Transvaginal sonography of acute pelvic inflammatory disease

International Nuclear Information System (INIS)

Choi, Jin Soo; Kim, Young Hwa; Shin, Hyung Chul; Han, Gun Soo; Kim, Il Young

1999-01-01

To determine the value of transvaginal sonography in evaluating women with acute pelvic inflammatory disease (PID). Transvaginal sonography was performed in 25 patients with clinically suggested PID during recent 36 months. The sonographic findings of fallopian tubes and ovaries were analyzed and correlated with pathological findings of 2 fallopian tubes and 19 ovaries in 16 patients who had operations. The correct diagnosis of acute PID was made in 20/25 (80%) by transvaginal sonography. the abnormal sonographic findings of the fallopian tube include tubal thickening or dilatation with internal echo. The sensitivity, specificity, and accuracy for tubal abnormality were 88%, 96%, and 86% , respectively. Ovarian changes were seen on TVS in 14/19 (73%), which include multiple follicular enlargement in 5, tubo-ovarian complex in 9 (tubo-ovarian adhesion in 3, tubo-ovarian abscess in 6). At surgery, the ovay was not involved in all three women who showed tubo-ovarian adhesion on TVS. Among 6 women who showed tubo-ovarian abscess on TVS, tubo-ovarian abscess was confirmed in 3 and the remaining 3 had ovarian cysts. Trandvaginal sonography, a facilitative and accurate modality, is highly sensitive in detecting the abnormality of the tube and useful in differentiating the tubo-ovarian complex in patients with acute PID.

Radiofrequency Ablation Assisted by Real-Time Virtual Sonography and CT for Hepatocellular Carcinoma Undetectable by Conventional Sonography

International Nuclear Information System (INIS)

Nakai, Motoki; Sato, Morio; Sahara, Shinya; Takasaka, Isao; Kawai, Nobuyuki; Minamiguchi, Hiroki; Tanihata, Hirohiko; Kimura, Masashi; Takeuchi, Nozomu

2009-01-01

Real-time virtual sonography (RVS) is a diagnostic imaging support system, which provides the same cross-sectional multiplanar reconstruction images as ultrasound images on the same monitor screen in real time. The purpose of this study was to evaluate radiofrequency ablation (RFA) assisted by RVS and CT for hepatocellular carcinoma (HCC) undetectable with conventional sonography. Subjects were 20 patients with 20 HCC nodules not detected by conventional sonography but detectable by CT or MRI. All patients had hepatitis C-induced liver cirrhosis; there were 13 males and 7 females aged 55-81 years (mean, 69.3 years). RFA was performed in the CT room, and the tumor was punctured with the assistance of RVS. CT was performed immediately after puncture, and ablation was performed after confirming that the needle had been inserted into the tumor precisely. The mean number of punctures and success rates of the first puncture were evaluated. Treatment effects were evaluated with dynamic CT every 3 months after RFA. RFA was technically feasible and local tumor control was achieved in all patients. The mean number of punctures was 1.1, and the success rate of the first puncture was 90.0%. This method enabled safe ablation without complications. The mean follow-up period was 13.5 month (range, 9-18 months). No local recurrence was observed at the follow-up points. In conclusion, RFA assisted by RVS and CT is a safe and efficacious method of treatment for HCC undetectable by conventional sonography.

DOPPLER SIGNATURES OF THE ATMOSPHERIC CIRCULATION ON HOT JUPITERS

International Nuclear Information System (INIS)

Showman, Adam P.; Lewis, Nikole K.; Fortney, Jonathan J.; Shabram, Megan

2013-01-01

The meteorology of hot Jupiters has been characterized primarily with thermal measurements, but recent observations suggest the possibility of directly detecting the winds by observing the Doppler shift of spectral lines seen during transit. Motivated by these observations, we show how Doppler measurements can place powerful constraints on the meteorology. We show that the atmospheric circulation—and Doppler signature—of hot Jupiters splits into two regimes. Under weak stellar insolation, the day-night thermal forcing generates fast zonal jet streams from the interaction of atmospheric waves with the mean flow. In this regime, air along the terminator (as seen during transit) flows toward Earth in some regions and away from Earth in others, leading to a Doppler signature exhibiting superposed blueshifted and redshifted components. Under intense stellar insolation, however, the strong thermal forcing damps these planetary-scale waves, inhibiting their ability to generate jets. Strong frictional drag likewise damps these waves and inhibits jet formation. As a result, this second regime exhibits a circulation dominated by high-altitude, day-to-night airflow, leading to a predominantly blueshifted Doppler signature during transit. We present state-of-the-art circulation models including non-gray radiative transfer to quantify this regime shift and the resulting Doppler signatures; these models suggest that cool planets like GJ 436b lie in the first regime, HD 189733b is transitional, while planets hotter than HD 209458b lie in the second regime. Moreover, we show how the amplitude of the Doppler shifts constrains the strength of frictional drag in the upper atmospheres of hot Jupiters. If due to winds, the ∼2 km s –1 blueshift inferred on HD 209458b may require drag time constants as short as 10 4 -10 6 s, possibly the result of Lorentz-force braking on this planet's hot dayside.

Rotator cuff ruptures of the shoulder joint, sonography - arthrography

International Nuclear Information System (INIS)

Triebel, H.J.; Wening, V.; Witte, G.; Hamburg Univ.

1986-01-01

47 patients suspected of rutpure of the rotator cuff were sonographed and arthrographed. Rupture of the rotator cuff was diagnosed in 12 cases, both diagnostic methods yielding the same result. In 29 patients sonography and arthrography did not reveal any abnormal findings. Six ruptures evident in sonography were not confirmed by arthrography and were considered false positive. Direct pointers towards rupture of the cuff would be: echoless defects, cuff cannot be visualised fully or in part and irregularities of movement during dynamic examination. Echoless 'cystic' areas in the periarticular soft parts must be considered an indirect pointer. Echorich focal findings in the echopoor cuff represent a differential diagnostic problem and we cannot give a final assessment as yet. Shoulder sonography is justified as a screening method in suspicion of rotator cuff rupture before initiating arthrography. If sonography reveals no abnormal findings, shoulder arthrography need not be performed. (orig.) [de

On the influence of ocean waves on simulated GNSS-R delay-doppler maps

Science.gov (United States)

Clarizia, M. P.; di Bisceglie, M.; Galdi, C.; Gommenginger, C.; Srokosz, M.

2012-04-01

Global Navigation Satellite System-Reflectometry (GNSS-R), is an established technique that exploits GNSS signals of opportunity reflected from the surface of the ocean, to look primarily at the ocean surface roughness. The strength of this technique, and the primary motivation to carry it forward, is in the fact that GNSS signals are available globally, all the time and over the long term, and could help dramatically improve the monitoring of ocean wind and waves. GNSS-R offers the prospect of high density global measurements of directional sea surface roughness, which are essential for scientific purposes (i.e. quantifying the air-sea exchanges of gases), operational weather and ocean forecasting (i.e. prediction of high winds, dangerous sea states, risk of flooding and storm surges) and to support important climate-relevant Earth Observation techniques (IR SST, or surface salinity retrieval). The retrieval of ocean roughness from GNSS-R data has now been demonstrated with a reasonable level of accuracy from both airborne [1] and spaceborne [2] platforms. In both cases, Directional Mean Square Slopes (DMSS) of the ocean surface have been retrieved from GNSS-R data, in the form of Delay-Doppler Maps (DDMs), using an established theoretical scattering model by Zavorotny and Voronovich (Z-V) [3]. The need for a better assessment of the way the ocean waves influence the scattering of GPS signals has recently led to a different approach, consisting of simulating the scattering of such signals, using a more sophisticated large-scale scattering model than Z-V, and explicit simulations of realistic seas. Initial results produced from these simulations have been recently published in [4], where the emphasis has been put on the effects of different sea states on Radar Cross Section (RCS) and Polarization Ratio (PR) in space domain. Linear wind wave surfaces have been simulated using the Elfouhaily wind wave spectrum [5], for different wind speeds and directions, and with

Two- and three-dimensional transvaginal ultrasound with power Doppler angiography and gel infusion sonography for diagnosis of endometrial malignancy.

Science.gov (United States)

Dueholm, M; Christensen, J W; Rydbjerg, S; Hansen, E S; Ørtoft, G

2015-06-01

To evaluate the diagnostic efficiency of two-dimensional (2D) and three-dimensional (3D) transvaginal ultrasonography, power Doppler angiography (PDA) and gel infusion sonography (GIS) at offline analysis for recognition of malignant endometrium compared with real-time evaluation during scanning, and to determine optimal image parameters at 3D analysis. One hundred and sixty-nine consecutive women with postmenopausal bleeding and endometrial thickness ≥ 5 mm underwent systematic evaluation of endometrial pattern on 2D imaging, and 2D videoclips and 3D volumes were later analyzed offline. Histopathological findings at hysteroscopy or hysterectomy were used as the reference standard. The efficiency of the different techniques for diagnosis of malignancy was calculated and compared. 3D image parameters, endometrial volume and 3D vascular indices were assessed. Optimal 3D image parameters were transformed by logistic regression into a risk of endometrial cancer (REC) score, including scores for body mass index, endometrial thickness and endometrial morphology at gray-scale and PDA and GIS. Offline 2D and 3D analysis were equivalent, but had lower diagnostic performance compared with real-time evaluation during scanning. Their diagnostic performance was not markedly improved by the addition of PDA or GIS, but their efficiency was comparable with that of real-time 2D-GIS in offline examinations of good image quality. On logistic regression, the 3D parameters from the REC-score system had the highest diagnostic efficiency. The area under the curve of the REC-score system at 3D-GIS (0.89) was not improved by inclusion of vascular indices or endometrial volume calculations. Real-time evaluation during scanning is most efficient, but offline 2D and 3D analysis is useful for prediction of endometrial cancer when good image quality can be obtained. The diagnostic efficiency at 3D analysis may be improved by use of REC-scoring systems, without the need for calculation of

Colour Doppler evaluation of extracranial carotid artery in patients presenting with features of cerebrovascular disease: A clinical and radiological correlation

Directory of Open Access Journals (Sweden)

Sanjeev Sehrawat

2012-01-01

Full Text Available Aim: To evaluate the morphological and hemodynamic changes that take place in carotid arteries by colour Doppler in patients presenting with features of stroke. Background and Objectives: Cerebrovascular accidents constitute a major cause of adult mortality. The principal indication for cerebrovascular Doppler examination is stroke prevention. Colour Doppler sonography is a sensitive method for detection of atherosclerotic plaque and provides considerable information about the extent and severity of plaque as well as the resulting diminution of arterial lumen. The main strengths of sonography of carotid arteries are patient comfort, lack of risk and accuracy in detecting carotid stenosis. Material and Methods: A prospective study of Colour Doppler in carotid arteries was carried out for 12 months from 1 st July 2009 to 1 st July 2010. The study was carried out on 40 individuals, suspected of cerebrovascular insufficiency and having one or the other risk factors for cerebrovascular disease. A detailed clinical history, CNS examination findings and evidence of hypertension, diabetes mellitus, hyperlipidemia and ischemic heart disease were noted. Carotid Doppler evaluation was done by using Siemens Antares Ultrasound system. The data gathered were grey scale and Doppler findings of common carotid artery, internal carotid artery and external carotid arteries. Doppler findings were correlated with clinical features and risk factors. Results: In our study of 40 patients, the commonest lesion found was the atherosclerotic plaque. Highest incidence of plaque was seen in males 41% in the age group of 60-70 years and in females 37% in age group of 70-80 years. Cigarette smoking was the most common risk factor (60% associated with stroke/ Transient Ischaemic Attacks (TIA. Hemiparesis was the most common presenting symptom (35% among the symptomatic cases. Atheromatous plaque was most commonly found in the right carotid system (60%. Most common site for

The accuracy of transvaginal sonography to detect endometriosis cyst

Science.gov (United States)

Diantika, M.; Gunardi, E. R.

2017-08-01

Endometriosis is common in women of reproductive age. Late diagnosis is still the main concern. Currently, noninvasive diagnostic testing, such as transvaginal sonography, is recommended. The aim of the current study was to evaluate the accuracy of transvaginal sonography in diagnosing endometrial cysts in patients in Cipto Mangunkusumo Hospital, Jakarta, Indonesia. This diagnostic study was carried out at Cipto Mangunkusumo Hospital between January 2014 and June 2015. Outpatients suspected have an endometrial cyst based on the patient history and a clinical examination was recruited. The patients were then evaluated using transvaginal sonography by an experienced sonologist, according to the research protocol. The gold standard test was a histological finding in the removed surgical mass. Ninety-eight patients were analyzed. An endometrial cyst was confirmed by histology in 85 patients (87%). The accuracy, sensitivity, specificity, positive predictive value and negative predictive value of transvaginal sonography was established to be 85% (a range of 71-99%), 93%, 77%, 96%, and 63%, respectively. A significantly higher area under the curve was identified using transvaginal sonogpraphy compared to that achieved with a clinical examination alone (85% versus 79%). Transvaginal sonography was useful in diagnosing endometrial cysts in outpatients and is recommended in daily clinical practice.

Material properties identification using ultrasonic waves and laser Doppler vibrometer measurements: a multi-input multi-output approach

International Nuclear Information System (INIS)

Longo, R; Vanlanduit, S; Guillaume, P

2013-01-01

In this paper a multi-input multi-output approach able to determine the material properties of homogeneous materials is presented. To do so, an experimental set-up which combines the use of multi harmonic signals with interleaved frequencies and laser Doppler vibrometer measurements has been developed. A modeling technique, based on transmission and reflection measurements, allowed the simultaneous determination of longitudinal wave velocity, density and thickness of the materials under test with high levels of precision and accuracy. (paper)

Mammography and breast sonography in transsexual women

International Nuclear Information System (INIS)

Weyers, S.; Villeirs, G.; Vanherreweghe, E.; Verstraelen, H.; Monstrey, S.; Van den Broecke, R.; Gerris, J.

2010-01-01

Data on the necessity of performing screening mammographies in transsexual women are lacking. The main objective of this study was to assess the possibility to perform mammography and breast sonography in transsexual women. Fifty Dutch-speaking transsexual women were interviewed about the following: attitude towards mammography and breast sonography, importance attributed to and satisfaction with breast appearance, opinion about the necessity of breast check-up, expectations regarding discomfort during the exams and knowledge about the breast surgery. A fasting blood sample, clinical breast exam, mammography and breast sonography were performed. At mammography the following parameters were noted: density, technical quality, location of the prostheses, presence of any abnormalities and painfulness. At sonography the following parameters were recorded: density, presence of cysts, visualisation of retro-areolar ducts or any abnormalities. Twenty-three percent of patients are not aware of the type of breast implants and 79% do not know their position to the pectoral muscles. Patient satisfaction with the appearance of their breasts was rather high (7.94 on a scale of 0-10). Mean expected and experienced pain from mammography was low (4.37 and 2.00 respectively). There was no statistically significant difference in expected pain between those who already had mammography and those who did not. There was a significant positive correlation between the expected and the experienced pain. Mammography and breast sonography were technically feasible and no gross anomalies were detected. Since both exams were judged as nearly painless, 98% of transsexual women intended to come back if they would be invited. Since breast cancer risk in transsexual women is largely unknown and breast exams are very well accepted, breast screening habits in this population should not differ from those of biological women.

Mammography and breast sonography in transsexual women

Energy Technology Data Exchange (ETDEWEB)

Weyers, S., E-mail: steven.weyers@ugent.b [Department of Gynecology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent (Belgium); Villeirs, G.; Vanherreweghe, E. [Department of Radiology, Ghent University Hospital, Ghent (Belgium); Verstraelen, H. [Department of Gynecology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent (Belgium); Monstrey, S. [Department of Plastic Surgery, Ghent University Hospital, Ghent (Belgium); Van den Broecke, R.; Gerris, J. [Department of Gynecology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent (Belgium)

2010-06-15

Data on the necessity of performing screening mammographies in transsexual women are lacking. The main objective of this study was to assess the possibility to perform mammography and breast sonography in transsexual women. Fifty Dutch-speaking transsexual women were interviewed about the following: attitude towards mammography and breast sonography, importance attributed to and satisfaction with breast appearance, opinion about the necessity of breast check-up, expectations regarding discomfort during the exams and knowledge about the breast surgery. A fasting blood sample, clinical breast exam, mammography and breast sonography were performed. At mammography the following parameters were noted: density, technical quality, location of the prostheses, presence of any abnormalities and painfulness. At sonography the following parameters were recorded: density, presence of cysts, visualisation of retro-areolar ducts or any abnormalities. Twenty-three percent of patients are not aware of the type of breast implants and 79% do not know their position to the pectoral muscles. Patient satisfaction with the appearance of their breasts was rather high (7.94 on a scale of 0-10). Mean expected and experienced pain from mammography was low (4.37 and 2.00 respectively). There was no statistically significant difference in expected pain between those who already had mammography and those who did not. There was a significant positive correlation between the expected and the experienced pain. Mammography and breast sonography were technically feasible and no gross anomalies were detected. Since both exams were judged as nearly painless, 98% of transsexual women intended to come back if they would be invited. Since breast cancer risk in transsexual women is largely unknown and breast exams are very well accepted, breast screening habits in this population should not differ from those of biological women.

Trans-skull ultrasonic Doppler system aided by fuzzy logic

Science.gov (United States)

Hata, Yutaka; Nakamura, Masato; Yagi, Naomi; Ishikawa, Tomomoto

2012-06-01

This paper describes a trans-skull ultrasonic Doppler system for measuring the blood flow direction in brain under skull. In this system, we use an ultrasonic array probe with the center frequency of 1.0 MHz. The system determines the fuzzy degree of blood flow by Doppler Effect, thereby it locates blood vessel. This Doppler Effect is examined by the center of gravity shift of the frequency magnitudes. In in-vitro experiment, a cow bone was employed as the skull, and three silicon tubes were done as blood vessels, and bubble in water as blood. We received the ultrasonic waves through a protein, the skull and silicon tubes in order. In the system, fuzzy degrees are determined with respect to the Doppler shift, amplitude of the waves and attenuation of the tissues. The fuzzy degrees of bone and blood direction are calculated by them. The experimental results showed that the system successfully visualized the skull and flow direction, compared with the location and flow direction of the phantom. Thus, it detected the flow direction by Doppler Effect under skull, and automatically extracted the region of skull and blood vessel.

Marked Increase in Flow Velocities During Deep Expiration: A Duplex Doppler Sign of Celiac Artery Compression Syndrome

International Nuclear Information System (INIS)

Erden, Ayse; Yurdakul, Mehmet; Cumhur, Turhan

1999-01-01

Symptoms of chronic mesenteric ischemia develop when the celiac artery is constricted by the median arcuate ligament of the diaphragm. Lateral aortography is the primary modality for diagnosing ligamentous compression of the celiac artery. However, duplex Doppler sonography performed during deep expiration can cause a marked increase in flow velocities at the compressed region of the celiac artery and suggest the diagnosis of celiac arterial constriction due to the diaphragmatic ligament. RID='''' ID='''' Correspondence to: A. Erden, M.D., Hafta sokak. 23/6, Gaziosmanpasa, 06700 Ankara, Turkey

Ultrasound Pulsed-Wave Doppler Detects an Intrathecal Location of an Epidural Catheter Tip: A Case Report.

Science.gov (United States)

Elsharkawy, Hesham; Saasouh, Wael; Patel, Bimal; Babazade, Rovnat

2018-04-01

Currently, no gold standard method exists for localization of an epidural catheter after placement. The technique described in this report uses pulsed-wave Doppler (PWD) ultrasound to identify intrathecal location of an epidural catheter. A thoracic epidural catheter was inserted after multiple trials with inconclusive aspiration and test dose. Ultrasound PWD confirmed no flow in the epidural space and positive flow in the intrathecal space. A fluid aspirate was positive for glucose, reconfirming intrathecal placement. PWD is a potential tool that can be used to locate the tip of an epidural catheter.

Measurements of ultrasonic waves by means of laser Doppler velocimeter and an experimental study of elastic wave propagation in inhomogeneous media; Laser doppler sokudokei ni yoru choonpa keisoku to ganseki wo mochiita fukinshitsu baishitsu no hado denpa model jikken

Energy Technology Data Exchange (ETDEWEB)

Nishizawa, O; Sato, T [Geological Survey of Japan, Tsukuba (Japan); Lei, X [Dia Consultants Company, Tokyo (Japan)

1996-05-01

In the study of seismic wave propagation, a model experimenting technique has been developed using a laser Doppler velocimeter (LDV) as the sensor. This technique, not dependent on conventional piezoelectric devices, only irradiates the specimen with laser to measure the velocity amplitude on the target surface, eliminating the need for close contact between the specimen and sensor. In the experiment, elastic penetration waves with their noise levels approximately 0.05mm/s were observed upon application of vibration of 10{sup 6}-10{sup 5}Hz. The specimen was stainless steel or rock, and waveforms caught by the LDV and piezoelectric device were compared. As the result, it was found that the LDV is a powerful tool for effectively explaining elastic wave propagation in inhomogeneous media. The piezoelectric device fails to reproduce accurately the waves to follow the initial one while the LDV detect the velocity amplitude on the specimen surface in a wide frequency range encouraging the discussion over the quantification of observed waveforms. 10 refs., 7 figs.

Ionospheric oscillations caused by geomagnetic Pi2 pulsations and their observations by multipoint continuous Doppler sounding; first results

Czech Academy of Sciences Publication Activity Database

Chum, Jaroslav; Hruška, František; Burešová, Dalia; Šindelářová, Tereza; Hejda, Pavel; Bochníček, Josef

2009-01-01

Roč. 44, č. 6 (2009), s. 667-676 ISSN 0273-1177 R&D Projects: GA ČR GA205/07/1367; GA ČR GA205/06/0875; GA AV ČR 1QS300120506; GA AV ČR IAA300420603 Institutional research plan: CEZ:AV0Z30420517; CEZ:AV0Z30120515 Keywords : Magnetosphere–ionosphere interactions * Ionosphere irregularities * Geomagnetic pulsations * Doppler sounding * Magneto-hydrodynamic (ULF) waves Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.079, year: 2009

Power Doppler flow mapping and four-dimensional ultrasound for evaluating tubal patency compared with laparoscopy.

Science.gov (United States)

Soliman, Amr A; Shaalan, Waleed; Abdel-Dayem, Tamer; Awad, Elsayed Elbadawy; Elkassar, Yasser; Lüdders, Dörte; Malik, Eduard; Sallam, Hassan N

2015-12-01

To study the accuracy of four-dimensional (4D) ultrasound and power Doppler flow mapping in detecting tubal patency in women with sub-/infertility, and compare it with laparoscopy and chromopertubation. A prospective study. The study was performed in the outpatient clinic and infertility unit of a university hospital. The sonographic team and laparoscopic team were blinded to the results of each other. Women aged younger than 43 years seeking medical advice due to primary or secondary infertility and who planned to have a diagnostic laparoscopy performed, were recruited to the study after signing an informed consent. All of the recruited patients had power Doppler flow mapping and 4D hysterosalpingo-sonography by injecting sterile saline into the fallopian tubes 1 day before surgery. Registering Doppler signals, while using power Doppler, both at the tubal ostia and fimbrial end and the ability to demonstrate the course of the tube especially the isthmus and fimbrial end, while using 4D mode, was considered a patent tube. Out of 50 recruited patients, 33 women had bilateral patent tubes and five had unilateral patent tubes as shown by chromopertubation during diagnostic laparoscopy. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for two-dimensional power Doppler hysterosalpingography were 94.4%, 100%, 100%, 89.2%, and 96.2%, respectively and for 4D ultrasound were 70.4%, 100%, 100%, 70.4%, and 82.6%, respectively. Four-dimensional saline hysterosalpingography has acceptable accuracy in detecting tubal patency, but is surpassed by power Doppler saline hysterosalpingography. Power Doppler saline hysterosalpingography could be incorporated into the routine sub-/infertility workup. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Feasibility of UltraFast Doppler in Post-operative Evaluation of Hepatic Artery in Recipients following Liver Transplantation.

Science.gov (United States)

Kim, Se-Young; Kim, Kyoung Won; Choi, Sang Hyun; Kwon, Jae Hyun; Song, Gi-Won; Kwon, Heon-Ju; Yun, Young Ju; Lee, Jeongjin; Lee, Sung-Gyu

2017-11-01

To determine the feasibility of using UltraFast Doppler in post-operative evaluation of the hepatic artery (HA) after liver transplantation (LT), we evaluated 283 simultaneous conventional and UltraFast Doppler sessions in 126 recipients over a 2-mo period after LT, using an Aixplorer scanner The Doppler indexes of the HA (peak systolic velocity [PSV], end-diastolic velocity [EDV], resistive index [RI] and systolic acceleration time [SAT]) by retrospective analysis of retrieved waves from UltraFast Doppler clips were compared with those obtained by conventional spectral Doppler. Correlation, performance in diagnosing the pathologic wave, examination time and reproducibility were evaluated. The PSV, EDV, RI and SAT of spectral and UltraFast Doppler measurements exhibited excellent correlation with favorable diagnostic performance. During the bedside examination, the mean time spent for UltraFast clip storing was significantly shorter than that for conventional Doppler US measurements. Both conventional and UltraFast Doppler exhibited good to excellent inter-analysis consistency. In conclusion, compared with conventional spectral Doppler, UltraFast Doppler values correlated excellently and yielded acceptable pathologic wave diagnostic performance with reduced examination time at the bedside and excellent reproducibility. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

The value of computer tomography and sonography in the investigation of the pancreas

International Nuclear Information System (INIS)

Lackner, K.; Frommhold, H.; Grauthoff, H.; Moedder, U.; Heuser, L.; Braun, G.; Buurman, R.; Scherer, K.; Hamburg Univ.; Koeln Univ.

1980-01-01

Three hundred and five patients were examined by computer tomography and sonography. In 117 patients no abnormalities were found in the pancreas. The accuracy of computer tomography was 87%, of sonography 85%. In 41 patients the presence of a carcinoma of the pancreas was confirmed histologically. In this group the sensitivity of computer tomography was 83%, of sonography 85%. Thirty-four patients suffered from acute pancreatitis. In this group sensitivity of the two methods was equal at 79%. 113 patients had changes of chronic pancreatitis. Sensitivity of computer tomography was 84%, of sonography 70%. Computer tomography is better at demonstrating calcification in the pancreas. Atrophy of the pancreas cannot be diagnosed by sonography. (orig.) [de

Ratio of left ventricular peak E-wave velocity to flow propagation velocity assessed by color M-mode Doppler echocardiography in first myocardial infarction

DEFF Research Database (Denmark)

Møller, J E; Søndergaard, E; Seward, J B

2000-01-01

OBJECTIVES: To determine the ability of the ratio of peak E-wave velocity to flow propagation velocity (E/Vp) measured with color M-mode Doppler echocardiography to predict in-hospital heart failure and cardiac mortality in an unselected consecutive population with first myocardial infarction (MI...

Sonography in the 29th Olympic and Paralympic Games: a retrospective analysis.

Science.gov (United States)

He, Wen; Xiang, Dong-ying; Dai, Jian-ping

2011-01-01

The purpose of this study was to evaluate the application of sonography at the polyclinic of the Olympic/Paralympic village during the Olympic/Paralympic Games. We retrospectively reviewed 759 consecutive patients who underwent sonography at the ultrasound division of the polyclinic in the Olympic/Paralympic village from July 20, 2008, to September 20, 2008. Prevalence of emergency sonography after sports injury and non-sports-related urgent conditions during the games was analyzed. The benefit of sonographic services in large sporting events was discussed. There were 759 patients (484 athletes, 101 coaches, 88 team officials, and 86 volunteers; 462 men and 297 women) in the ultrasound division at the polyclinic. The indications for sonography included abdominal pain (315 cases, 41.50%), muskuloskeletal disorders (228 cases, 30.04%), gynecology related (104 cases, 13.70%), cardiac conditions (49 cases, 6.46%), small parts (29 cases, 3.82%), and vascular problems (34 cases, 4.48%). The rates of positive findings on sonography were 46.03% in the abdomen, 70.17% in musculoskeleton, 41.34% in gynecology, 10.20% in the heart, 75.86% in small parts, and 38.24% in vessels, respectively. Sonography plays an important role in the medical services at the polyclinic in the Olympic/Paralympic village. The benefits of sonography in such large sporting events are accuracy, fast result, portability, and noninvasiveness. Copyright © 2011 Elsevier Inc. All rights reserved.

Color doppler flow imaging in evaluation of uterine arterial embolization of leiomyoma with KMG

International Nuclear Information System (INIS)

Li Furong; Guo Yunhuai; Liu Lifang; Liu Jianhua; Guo Yunhuai

2006-01-01

Objective: To explore the effectiveness of a new kind of embolization agent-sodium alginate(KMG), and to evaluate the clinical value of 2D color Doppler ultrasound in assessing the therapeutic effect of uterine arterial embolization (UAE) in leiomyomas. Methods: Forty nine patients with symptomatic leiomyomas were undertaken UAE with KMG for the treatment. Sonography was performed at 3-7 days before and, 1, 3, 6 months after UAE with 2D color Doppler for evaluating the 2D echograms and hemodynamics. Results: Forty nine leiomyomas were studied after UAE, showing a marked reduction in the size (35%-90%). No blood flow was demonstrated in the leiomyomas either 3-7 days or 1 month or 3 months after the procedure. The reappearance of blood flow could be seen in only one case. Conclusion: KMG is an efficient embolization agent for the treatment of symptomatic leiomyomas with UAE, and ultrasonography is a useful tool to assess the effectiveness. (authors)

正常中晚期妊娠输尿管射尿的彩色多普勒检查%Observations of ureteral jets in normal second- and third-trimester pregnancy with color Doppler sonography

Institute of Scientific and Technical Information of China (English)

王家刚

2001-01-01

目的：了解正常中晚期妊娠输尿管的尿动力学改变是否影响输尿管射尿。方法：彩色多普勒超声观察32例中晚期妊娠妇女和11例非妊娠对照者膀胱射尿情况，观察时间5分钟。结果：妊娠受试者平均射尿5.9次/分，左、右侧射尿频率平均差异百分比为49％。对照组平均射尿7.3次/分，左、右射尿频率差异百分比为13％。受试组与对照组之间射尿对称性方面具有显著性差异(P＜0.05)。32例妊娠受试者中有7例有单侧射尿缺乏，而对照者中无1例单侧射尿缺乏。结论：在妊娠中晚期，由于两侧输尿管射尿的不对称性，用彩色多普勒超声检测输尿管射尿诊断中晚期妊娠合并输尿管结石应慎用。%Objective: To understand whether ureteral urodynamic changes accompanying normal second- and third-trimester pregnancy altered the pattern of ureteral jets. Methods: Ureteral jets were observed with color Doppler sonography for five minutes in 32women during the second or third trimester of pregnancy and in 11 non-pregnant controls. Result: A mean of 5.9 jets/ minute were detected in the pregnant subjects. The mean percentage difference in frequency of jets between the right and left sides was 49%. A mean of 7.3 jets/ minute were detected and the mean percentage difference was 13% for controls. The two groups were significantly different in jet symmetry (P＜0.05). Unilateral absence of jets was observed in seven pregnant subjects and in no controls. Conclusion: Because of asymmetry in ureteral jet between the left and right sides during the later stages of pregnacy, caution is recommended in the use of color Doppler sonography to diagnose ureteral urolithiasis during the later stages of pregnancy.

Physical model experiment for wave field measurements by means of laser Doppler vibrometer. Measurement of three components; Laser Doppler shindokei ni yoru butsuri model jikken. Hado sanseibun no kenshutsu

Energy Technology Data Exchange (ETDEWEB)

Nishizawa, O; Sato, T [Geological Survey of Japan, Tsukuba (Japan); Lei, X [DIA Consultant Co. Ltd., Tokyo (Japan)

1997-05-27

In this experiment, a beam incident from an oblique direction is reflected by a spherical lens toward the direction of incidence. When the surface of a matter is vibrated by elastic waves, the spherical lens comes into a translation motion that accompanies the vibration. It follows accordingly that the vibration on the surface of the matter may be detected by sensing the spherical lens travelling speed. Three components of the vibration may be determined if beams are focused at one spot from three directions. Detection of the S-wave component by LDV (laser Doppler vibrometer) discloses the complicated wave field in a heterogeneous material, and this physical model experiment may be utilized in various fields of study. For instance, information about problems that may surface in the field work may be collected beforehand in a physical model experiment for developing an S-wave-aided probing method. For the study of seismic wave propagation in a complicated three-dimensional ground structure, a numerical model is not enough, and a physical model experiment will be an effective method to fulfill the purpose. In the monitoring of cracks in a rock, again, not only elastic wave velocity but also waveform information collected from a physical model experiment should be fully utilized. 6 refs., 6 figs.

Doppler Velocity Signatures of Idealized Elliptical Vortices

Directory of Open Access Journals (Sweden)

Wen-Chau Lee

2006-01-01

Full Text Available Doppler radar observations have revealed a class of atmospheric vortices (tropical cyclones, tornadoes, dust devils that possess elliptical radar reflectivity signatures. One famous example is Typhoon Herb (1996 that maintained its elliptical reflectivity structure over a 40-hour period. Theoretical work and dual-Doppler analyses of observed tropical cyclones have suggested two physical mechanisms that can explain the formation of two types of elliptical vortices observed in nature, namely, the combination of a circular vortex with either a wavenumber two vortex Rossby wave or a deformation field. The characteristics of these two types of elliptical vortices and their corresponding Doppler velocity signatures have not been previously examined.

Detection of gravitational radiation by the Doppler tracking of spacecraft

International Nuclear Information System (INIS)

Mashhoon, B.

1979-01-01

It has been suggested that the residual Doppler shift in the precision electromagnetic tracking of spacecraft be used to search for gravitational radiation that may be incident on the Earth-spacecraft system. The influence of a gravitational wave on the Doppler shift is calculated, and it is found that the residual shift is dominated by two terms: one is due to the passage of electromagnetic waves through the gravitational radiation field, and the other depends on the change in the relative velocity of the Earth and the spacecraft caused by the external wave. A detailed analysis is given of the influence of gravitational radiation on a binary system with an orbital size small compared to the wavelength of the incident radiation. It is shown that, as a consequence of the interaction with the external wave, the system makes a transition from one Keplerian orbit into another which, in general, has a different energy and angular momentum. It is therefore proposed to search for such effects in the solar system. Observations of the orbit of an artificial Earth satellite, the lunar orbit, and especially the planetary orbits offer exciting possibilities for the detection of gravitational waves of various wavelengths. From the results of the lunar laser ranging experiment and the range measurement to Mars, certain interesting limits may be established on the frequency of incidence of gravitational waves of a given flux on the Earth-Moon and the Earth-Mars systems. This is followed by a brief and preliminary analysis of the possibility of detecting gravitational radiation by measuring a residual secular Doppler shift in the satellite-to-satellite Doppler tracking of two counterorbiting drag-free spacecraft around the Earth as in the Van Patten-Everitt experiment

High-precision terahertz frequency modulated continuous wave imaging method using continuous wavelet transform

Science.gov (United States)

Zhou, Yu; Wang, Tianyi; Dai, Bing; Li, Wenjun; Wang, Wei; You, Chengwu; Wang, Kejia; Liu, Jinsong; Wang, Shenglie; Yang, Zhengang

2018-02-01

Inspired by the extensive application of terahertz (THz) imaging technologies in the field of aerospace, we exploit a THz frequency modulated continuous-wave imaging method with continuous wavelet transform (CWT) algorithm to detect a multilayer heat shield made of special materials. This method uses the frequency modulation continuous-wave system to catch the reflected THz signal and then process the image data by the CWT with different basis functions. By calculating the sizes of the defects area in the final images and then comparing the results with real samples, a practical high-precision THz imaging method is demonstrated. Our method can be an effective tool for the THz nondestructive testing of composites, drugs, and some cultural heritages.

Role of sonography in the diagnosis of Echinococcus alveolaris

Energy Technology Data Exchange (ETDEWEB)

Maier, W.

1983-02-01

Abdominal sonography and computed tomography were performed in eleven patients with operatively and histologically proven Echinococcus alveolaris of the liver and the detailed appearances were compared. Sonography is a useful screening method in the assessment of E. alveolaris, but its previous importance is being gradually superseded by computed tomography, which is capable of providing more detailed information in the diagnosis of Echinococcus infestation.

Clinical applications of imaging reconstruction by virtual sonography

International Nuclear Information System (INIS)

Mori, Akihiro; Oohashi, Noritsugu; Maruyama, Takako; Tatebe, Hideharu; Fushimi, Nobutoshi; Asano, Takayuki; Inoue, Hiroshi; Okuno, Masataka

2008-01-01

One of the pitfalls in managing multiple liver tumors is the difficulty in identifying individual tumors on ultrasonography. Computed tomography (CT)-assisted virtual sonography has been shown to improve sonographic diagnosis, however it requires additional equipment and software. We have developed a simple reconstruction method of virtual sonography (SRVS). We reconstructed SRVS mimicking ultrasonographic images, utilizing a workstation software attached to a multi-detector row CT system without any additional program. We have performed SRVS in 32 patients with 41 liver tumors that could hardly be identify on ultrasonography. SRVS assisted the identification of malignant form non-pathologic ones and thereby contributed to the appropriate clinical strategy including radiofrequency ablation (RFA) (18 tumors), liver biopsy (2 tumors), other therapies (4 tumors) and follow-up (17 tumors). We have developed virtual sonography using conventional CT software. SRVS seems useful in the clinical practice in managing liver tumors. (author)

Comparative study of the performance of semiconductor laser based coherent Doppler lidars

DEFF Research Database (Denmark)

Rodrigo, Peter John; Pedersen, Christian

2012-01-01

Coherent Doppler Lidars (CDLs), operating at an eye-safe 1.5-micron wavelength, have found promising applications in the optimization of wind-power production. To meet the wind-energy sector's impending demand for more cost-efficient industrial sensors, we have focused on the development of conti......Coherent Doppler Lidars (CDLs), operating at an eye-safe 1.5-micron wavelength, have found promising applications in the optimization of wind-power production. To meet the wind-energy sector's impending demand for more cost-efficient industrial sensors, we have focused on the development...... of continuous-wave CDL systems using compact, inexpensive semiconductor laser (SL) sources. In this work, we compare the performance of two candidate emitters for an allsemiconductor CDL system: (1) a monolithic master-oscillator-power-amplifier (MOPA) SL and (2) an external-cavity tapered diode laser (ECTDL)....

Intelligent navigation to improve obstetrical sonography.

Science.gov (United States)

Yeo, Lami; Romero, Roberto

2016-04-01

'Manual navigation' by the operator is the standard method used to obtain information from two-dimensional and volumetric sonography. Two-dimensional sonography is highly operator dependent and requires extensive training and expertise to assess fetal anatomy properly. Most of the sonographic examination time is devoted to acquisition of images, while 'retrieval' and display of diagnostic planes occurs rapidly (essentially instantaneously). In contrast, volumetric sonography has a rapid acquisition phase, but the retrieval and display of relevant diagnostic planes is often time-consuming, tedious and challenging. We propose the term 'intelligent navigation' to refer to a new method of interrogation of a volume dataset whereby identification and selection of key anatomical landmarks allow the system to: 1) generate a geometrical reconstruction of the organ of interest; and 2) automatically navigate, find, extract and display specific diagnostic planes. This is accomplished using operator-independent algorithms that are both predictable and adaptive. Virtual Intelligent Sonographer Assistance (VIS-Assistance®) is a tool that allows operator-independent sonographic navigation and exploration of the surrounding structures in previously identified diagnostic planes. The advantage of intelligent (over manual) navigation in volumetric sonography is the short time required for both acquisition and retrieval and display of diagnostic planes. Intelligent navigation technology automatically realigns the volume, and reorients and standardizes the anatomical position, so that the fetus and the diagnostic planes are consistently displayed in the same manner each time, regardless of the fetal position or the initial orientation. Automatic labeling of anatomical structures, subject orientation and each of the diagnostic planes is also possible. Intelligent navigation technology can operate on conventional computers, and is not dependent on specific ultrasound platforms or on the

Doppler Radar Vital Signs Detection Method Based on Higher Order Cyclostationary.

Science.gov (United States)

Yu, Zhibin; Zhao, Duo; Zhang, Zhiqiang

2017-12-26

Due to the non-contact nature, using Doppler radar sensors to detect vital signs such as heart and respiration rates of a human subject is getting more and more attention. However, the related detection-method research meets lots of challenges due to electromagnetic interferences, clutter and random motion interferences. In this paper, a novel third-order cyclic cummulant (TOCC) detection method, which is insensitive to Gaussian interference and non-cyclic signals, is proposed to investigate the heart and respiration rate based on continuous wave Doppler radars. The k -th order cyclostationary properties of the radar signal with hidden periodicities and random motions are analyzed. The third-order cyclostationary detection theory of the heart and respiration rate is studied. Experimental results show that the third-order cyclostationary approach has better estimation accuracy for detecting the vital signs from the received radar signal under low SNR, strong clutter noise and random motion interferences.

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-04-15

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.

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

Directory of Open Access Journals (Sweden)

Ji Young Hwang

2017-04-01

Full Text Available 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.

Diagnostic accuracy of sonography for pleural effusion: systematic review

Directory of Open Access Journals (Sweden)

Alexandre Grimberg

Full Text Available CONTEXT AND OBJECTIVE: The initial method for evaluating the presence of pleural effusion was chest radiography. Isolated studies have shown that sonography has greater accuracy than radiography for this diagnosis; however, no systematic reviews on this matter are available in the literature. Thus, the aim of this study was to evaluate the accuracy of sonography in detecting pleural effusion, by means of a systematic review of the literature. DESIGN AND SETTING: This was a systematic review with meta-analysis on accuracy studies. This study was conducted in the Department of Diagnostic Imaging and in the Brazilian Cochrane Center, Discipline of Emergency Medicine and Evidence-Based Medicine, Department of Medicine, Universidade Federal de São Paulo (Unifesp, São Paulo, Brazil. METHOD: The following databases were searched: Cochrane Library, Medline, Web of Science, Embase and Literatura Latino-Americana e do Caribe em Ciências da Saúde (Lilacs. The references of relevant studies were also screened for additional citations of interest. Studies in which the accuracy of sonography for detecting pleural effusion was tested, with an acceptable reference standard (computed tomography or thoracic drainage, were included. RESULTS: Four studies were included. All of them showed that sonography had high sensitivity, specificity and accuracy for detecting pleural effusions. The mean sensitivity was 93% (95% confidence interval, CI: 89% to 96%, and specificity was 96% (95% CI: 95% to 98%. CONCLUSIONS: In different populations and clinical settings, sonography showed consistently high sensitivity, specificity and accuracy for detecting fluid in the pleural space.

Two-dimensional grayscale ultrasound and spectral Doppler waveform evaluation of dogs with chronic enteropathies.

Science.gov (United States)

Gaschen, Lorrie; Kircher, Patrick

2007-08-01

Sonography is an important diagnostic tool to examine the gastrointestinal tract of dogs with chronic diarrhea. Two-dimensional grayscale ultrasound parameters to assess for various enteropathies primarily focus on wall thickness and layering. Mild, generalized thickening of the intestinal wall with maintenance of the wall layering is common in inflammatory bowel disease. Quantitative and semi-quantitative spectral Doppler arterial waveform analysis can be utilized for various enteropathies, including inflammatory bowel disease and food allergies. Dogs with inflammatory bowel disease have inadequate hemodynamic responses during digestion of food. Dogs with food allergies have prolonged vasodilation and lower resistive and pulsatility indices after eating allergen-inducing foods.

Sonography for diagnosis of benign and malignant tumors of the nose and paranasal sinuses.

Science.gov (United States)

Liu, Jun-jie; Gao, Yong; Wu, Ya-Fei; Zhu, Shang-Yong

2014-09-01

The purpose of this study was to demonstrate the reliability of sonography for diagnosis of nose and paranasal sinus tumors. Ninety-six consecutive patients with tumors underwent sonography and computed tomography (CT) before surgical treatment. Tumor detectability and imaging findings were evaluated independently and then compared with pathologic findings. Of 96 tumors, 75 were detected by sonography, for a detectability rate of 78.1%; 93 tumors were detected by CT, for a detectability rate of 96.9%. By comparison, sonography showed a trend toward higher detectability of nasal vestibular tumors than CT (87.5% for sonography versus 50.0% for CT) and small lumps on the wing of the nose (78.8% for sonography versus 33.3% for CT). Among the sonographic features, boundary, shape, internal echo, calcification, bone invasion, vascular pattern, and cervical lymph node metastasis all had significantly positive correlations with malignancy (P benign and malignant tumors of the nose and paranasal sinuses. Consequently, sonography has high value for diagnosis of benign and malignant tumors of the nose and paranasal sinuses, especially for nasal vestibular tumors and small lumps on the wing of the nose. © 2014 by the American Institute of Ultrasound in Medicine.

Explanation of the Inverse Doppler Effect Observed in Nonlinear Transmission Lines

International Nuclear Information System (INIS)

Kozyrev, Alexander B.; Weide, Daniel W. van der

2005-01-01

The theory of the inverse Doppler effect recently observed in magnetic nonlinear transmission lines is developed. We explain the crucial role of the backward spatial harmonic in the occurrence of an inverse Doppler effect and draw analogies of the magnetic nonlinear transmission line to the backward wave oscillator

Differential diagnosis of persistent neonatal jaundice: Role of sonography and scintigraphy

International Nuclear Information System (INIS)

Lee, Sun Wha; Ko, Young Tae; Lim, Jae Hoon

1993-01-01

The most common causes of conjugated hyperbilirubinaemia after the first or second week of life are neonatal hepatitis and biliary atresia. Since these entities represent variable expressions of same pathologic process and have similar clinical, biochemical, and histologic features, differential diagnosis is extremely difficult. We prospectively studies 28 jaundiced infants by sonography and hepatobiliary scintigraphy. Final diagnoses included 12 biliary atresia and 16 neonatal hepatitis. Visualization of a normal sized common bile duct or gallbladder was compatible with the diagnosis of neonatal hepatitis. Non-visualized or atrophic gallbladder on sonography coupled with non-visualization of bowel activity on scintigraphy was highly suggestive of biliary atresia. We believe that sonography plays a valuable role in the initial evaluation of the infants with persistent neonatal jaundice. The combined use of sonography and hepatobiliary scintigraphy provides the most valuable information in suspected biliary atresia for prompt surgical treatment

Dual-Doppler Feasibility Study

Science.gov (United States)

Huddleston, Lisa L.

2012-01-01

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

Sonography in the postoperative evaluation of laparoscopic inguinal hernia repair.

Science.gov (United States)

Furtschegger, A; Sandbichler, P; Judmaier, W; Gstir, H; Steiner, E; Egender, G

1995-09-01

We evaluated the use of sonography as a means of assessing hernial occlusion and possible postoperative changes such as hematomas or seromas in the inguinal and scrotal regions after 1139 laparoscopic repairs of hernias between August 1992 and November 1994. Changes after laparoscopic hernia repair were found in 307 patients (27%). Hematomas or seromas were seen in 132 patients, protrusion of the prosthetic mesh in 17, mesh infection in two, and small bowel entrapment in an insufficient peritoneal suture in two. Recurrences were diagnosed correctly in six patients, mobile preperitoneal lipomas in five. Sonography is useful in the evaluation of complications after laparoscopic hernia repair, including recurrent hernia. In the absence of symptoms, sonography is not indicated.

Comparison of Sonography versus Digital Breast Tomosynthesis to Locate Intramammary Marker Clips.

Science.gov (United States)

Schulz-Wendtland, R; Dankerl, P; Dilbat, G; Bani, M; Fasching, P A; Heusinger, K; Lux, M P; Loehberg, C R; Jud, S M; Rauh, C; Bayer, C M; Beckmann, M W; Wachter, D L; Uder, M; Meier-Meitinger, M; Brehm, B

2015-01-01

Introduction: This study aimed to compare the accuracy of sonography versus digital breast tomosynthesis to locate intramammary marker clips placed under ultrasound guidance. Patients and Methods: Fifty patients with suspicion of breast cancer (lesion diameter less than 2 cm [cT1]) had ultrasound-guided core needle biopsy with placement of a marker clip in the center of the tumor. Intramammary marker clips were subsequently located with both sonography and digital breast tomosynthesis. Results: Sonography detected no dislocation of intrammammary marker clips in 42 of 50 patients (84 %); dislocation was reported in 8 patients (16 %) with a maximum dislocation of 7 mm along the x-, y- or z-axis. Digital breast tomosynthesis showed accurate placement without dislocation of the intramammary marker clip in 48 patients (96 %); 2 patients (4 %) had a maximum clip dislocation of 3 mm along the x-, y- or z-axis (p tomosynthesis could improve the accuracy when locating intramammary marker clips compared to sonography and could, in future, be used to complement or even completely replace sonography.

Principles and practice of sonography

International Nuclear Information System (INIS)

Fleischer, A.C.; James, A.E.

1987-01-01

This book is a text of sonographic technique, emphasizing clinical and diagnostic procedures. Ultrasound images and explanatory line drawings are placed side-by-side to facilitate interpretation. This book covers instrumentation and scanning principles, obstetric, gynecologic, abdominal, renal and urologic, pediatric, plus superficial structure sonography

Reliability and precision of stress sonography of the ulnar collateral ligament.

Science.gov (United States)

Bica, David; Armen, Joseph; Kulas, Anthony S; Youngs, Kevin; Womack, Zachary

2015-03-01

Musculoskeletal sonography has emerged as an additional diagnostic tool that can be used to assess medial elbow pain and laxity in overhead throwers. It provides a dynamic, rapid, and noninvasive modality in the evaluation of ligamentous structural integrity. Many studies have demonstrated the utility of dynamic sonography for medial elbow and ulnar collateral ligament (UCL) integrity. However, evaluating the reliabilityand precision of these measurements is critical if sonography is ultimately used as a clinical diagnostic tool. The purpose of this study was to evaluate the reliability and precision of stress sonography applied to the medial elbow. We conducted a cross-sectional study during the 2011 baseball off-season. Eighteen National Collegiate Athletic Association Division I pitchers were enrolled, and 36 elbows were studied. Using sonography, the medial elbow was assessed, and measurements of the UCL length and ulnohumeral joint gapping were performed twice under two conditions (unloaded and loaded) and bilaterally. Intraclass correlation coefficients (0.72-0.94) and standard errors of measurements (0.3-0.9 mm) for UCL length and ulnohumeral joint gapping were good to excellent. Mean differences between unloaded and loaded conditions for the dominant arms were 1.3 mm (gapping; P < .001) and 1.4 mm (UCL length; P < .001). Medial elbow stress sonography is a reliable and precise method for detecting changes in ulnohumeral joint gapping and UCL lengthening. Ultimately, this method may provide clinicians valuable information regarding the medial elbow's response to valgus loading and may help guide treatment options. © 2015 by the American Institute of Ultrasound in Medicine.

An ocean current inversion accuracy analysis based on a Doppler spectrum model

Institute of Scientific and Technical Information of China (English)

BAO Qingliu; ZHANG Youguang; LIN Mingsen; GONG Peng

2017-01-01

Microwave remote sensing is one of the most useful methods for observing the ocean parameters.The Doppler frequency or interferometric phase of the radar echoes can be used for an ocean surface current speed retrieval,which is widely used in spaceborne and airborne radars.While the effect of the ocean currents and waves is interactional.It is impossible to retrieve the ocean surface current speed from Doppler frequency shift directly.In order to study the relationship between the ocean surface current speed and the Doppler frequency shift,a numerical ocean surface Doppler spectrum model is established and validated with a reference.The input parameters of ocean Doppler spectrum include an ocean wave elevation model,a directional distribution function,and wind speed and direction.The suitable ocean wave elevation spectrum and the directional distribution function are selected by comparing the ocean Doppler spectrum in C band with an empirical geophysical model function (CDOP).What is more,the error sensitivities of ocean surface current speed to the wind speed and direction are analyzed.All these simulations are in Ku band.The simulation results show that the ocean surface current speed error is sensitive to the wind speed and direction errors.With VV polarization,the ocean surface current speed error is about 0.15 m/s when the wind speed error is 2 m/s,and the ocean surface current speed error is smaller than 0.3 m/s when the wind direction error is within 20° in the cross wind direction.

Galileo Probe Doppler Residuals as the Wave-Dynamical Signature of Weakly Stable, Downward-Increasing Stratification in Jupiter's Deep Wind Layer

Science.gov (United States)

Allison, Michael; Atkinson, David H.; Hansen, James E. (Technical Monitor)

2001-01-01

Doppler radio tracking of the Galileo probe-to-orbiter relay, previously analyzed for its in situ measure of Jupiter's zonal wind at the equatorial entry site, also shows a record of significant residual fluctuations apparently indicative of varying vertical motions. Regular oscillations over pressure depth in the residual Doppler measurements of roughly 1-8 Hz (increasing upward), as filtered over a 134 sec window, are most plausibly interpreted as gravity waves, and imply a weak, but downward increasing static stability within the 5 - 20 bar region of Jupiter's atmosphere. A matched extension to deeper levels of an independent inertial stability constraint from the measured vertical wind shear at 1 - 4 bars is roughly consistent with a static stability of approximately 0.5 K/km near the 20 bar level, as independently detected by the probe Atmospheric Structure Instrument.

Sonography and electrodiagnosis in carpal tunnel syndrome diagnosis, an analysis of the literature

International Nuclear Information System (INIS)

Seror, P.

2008-01-01

We present a review of the international literature concerning sonography for the diagnosis of carpal tunnel syndrome (CTS). Analysis of the results and comparison with electrodiagnostic data provide a sensible albeit personal view on the relevance of sonography and whether it competes or is complementary to electrodiagnosis (EDX). Although EDX is considered as the gold standard for CTS diagnosis, one author chose surgical results to define CTS. The normal and threshold mean values for sonography are particularly variable from one study to another. The standard deviation (S.D.), when compared to mean values, makes normal and abnormal data overlap considerably and produces many false negatives when the specificity is high, and many false positives when the sensitivity is high. In fact, sonography is non-interpretable in only 10 to 15% of the population, and it affirms the median nerve lesion at the wrist in 55% of cases when EDX does it in more than 90% with common tests. Further more the specificity of sonography leads to a false positive diagnosis in 1 case out of 5 versus 1 out of 40 with EDX. The main conclusion is that there is no competition but rather a complementarity between sonography and EDX: sonography is certainly an efficient imaging technique but cannot replace proper EDX performed for upper limb paresthesiae. Namely, sonography can answer only one out of the 8 questions a complete EDX answer: Are sonographic images compatible with a median nerve lesion at the wrist? The answer to this solely question can be obtain with a partial EDX using a single conduction test (motor or sensitive), then duration and cost will be comparable to sonography but will be both more sensitive and specific. Finally, one must kept in mind that the final aim of all examinations in CTS is to determine the cause(s) of upper limb paresthesiae, not simply if there is a median nerve lesion at wrist or not

Afferent loop syndrome: Role of sonography and CT

Energy Technology Data Exchange (ETDEWEB)

Lee, Dong Ho; Lim, Jae Hoon; Ko, Young Tae [Kyung Hee University Hospital, Seoul (Korea, Republic of)

1992-03-15

Afferent loop syndrome(ALS) is caused by obstruction of the afferent loop after subtotal gastrectomy with Billroth II gastrojejunostomy. Prompt diagnosis of ALS is important as perforation of the loop occurs. The aim of study is to ascertain the sonography and CT to diagnose ALS. We describe the radiologic findings in ten patients with ALS. The cause of ALS, established at surgery, included cancer recurrence (n=4), internal hernia (n=4), marginal ulcer (n=1), and development of cancer at the anastomosis site (n=1). Abdominal X-ray and sonography were performed in all cases, upper GI series in five cases and computed tomography in two cases. The dilated afferent loop was detected in only two cases out often patients in retrospective review of abdominal X-ray. ALS with recurrence of cancer was diagnosed in three cases by upper GI series. Of the cases that had sonography, the afferent loop was seen in the upper abdomen crossing transversely over the midline in all ten patients. The cause of ALS were predicated on the basis of the sonograms in three of the five patients. In two cases of computed tomography, the dilated afferent loop and recurrent cancer at the remnant stomach were seen.Our experience suggests that the diagnosis of afferent syndrome can be made on the basis of the typical anatomic location and shape of the dilated bowel loop in both sonography and computed tomography.

Cluster Observations of Non-Time Continuous Magnetosonic Waves

Science.gov (United States)

Walker, Simon N.; Demekhov, Andrei G.; Boardsen, Scott A.; Ganushkina, Natalia Y.; Sibeck, David G.; Balikhin, Michael A.

2016-01-01

Equatorial magnetosonic waves are normally observed as temporally continuous sets of emissions lasting from minutes to hours. Recent observations, however, have shown that this is not always the case. Using Cluster data, this study identifies two distinct forms of these non temporally continuous use missions. The first, referred to as rising tone emissions, are characterized by the systematic onset of wave activity at increasing proton gyroharmonic frequencies. Sets of harmonic emissions (emission elements)are observed to occur periodically in the region +/- 10 off the geomagnetic equator. The sweep rate of these emissions maximizes at the geomagnetic equator. In addition, the ellipticity and propagation direction also change systematically as Cluster crosses the geomagnetic equator. It is shown that the observed frequency sweep rate is unlikely to result from the sideband instability related to nonlinear trapping of suprathermal protons in the wave field. The second form of emissions is characterized by the simultaneous onset of activity across a range of harmonic frequencies. These waves are observed at irregular intervals. Their occurrence correlates with changes in the spacecraft potential, a measurement that is used as a proxy for electron density. Thus, these waves appear to be trapped within regions of localized enhancement of the electron density.

Superficial inflammatory and primary neoplastic lymphadenopathy: diagnostic accuracy of power-doppler sonography

International Nuclear Information System (INIS)

Magarelli, N.; Guglielmi, G.; Savastano, M.; Toro, V.; Sborgia, M.; Fioritoni, G.; Mattei, P.A.; Steinbach, L.; Bonomo, L.

2004-01-01

Objective: To evaluate the sensitivity, specificity and diagnostic accuracy of a cut-off of the resistive index of 0.5 for the differentiation between inflammatory and neoplastic primary lymphadenopathies. Subjects and methods: We measured the resistive index of superficial enlarged lymph nodes in a total of 50 patients (29 males and 21 females; age range 12-72 years, mean age 41.6 year) using an ATL 5000 HDI. A resistive index greater than or equal to 0.5 indicated an inflammatory lymph node and a resistive index <0.5 was consistent with neoplastic primary lymphadenopathies. The gold standard was either surgical biopsy or lymph-node reduction seen with ultrasound examination after antibiotic therapy. Results: The sensitivity of the resistive index for distinguishing inflammatory from neoplastic lymphadenopathy was 84.6%, the specificity 100% and the diagnostic accuracy 95.7% (P<0.001, statistically significant). Conclusion: The results of this study indicate that power-Doppler using a resistive index cut-off of 0.5 was a valid technique for distinguising between inflammatory and primary neoplastic lymph nodes in patients with superficial lymphadenopathies

Reframing conceptual physics: Improving relevance to elementary education and sonography majors

Science.gov (United States)

LaFazia, David Gregory

This study outlines the steps taken to reframe the Waves and Periodicity unit within a conceptual physics course. Beyond this unit reframing process, this paper explores the activities that made up the reframed unit and how each was developed and revised. The unit was reframed to improve relevance of the activities to the Elementary Education and Diagnostic Medical Sonography majors who make up the bulk of the course roster. The unit was reframed around ten design principles that were built on best practices from the literature, survey responses, and focused interviews. These principles support the selection of a biology-integrated themed approach to teaching physics. This is done through active and highly kinesthetic learning across three realms of human experience: physical, social, and cognitive. The unit materials were designed around making connections to students' future careers while requiring students to take progressively more responsibility in activities and assessments. Several support strategies are employed across these activities and assessments, including an energy-first, guided-inquiry approach to concept scaffolding and accommodations for diverse learners. Survey responses were solicited from physics instructors experienced with this population, Elementary Education and Sonography program advisors, and curriculum design, learning strategies, and educational technology experts. The reframed unit was reviewed by doctoral-level science education experts and revised to further improve the depth and transparency with which the design principles reframe the unit activities. The reframed unit contains a full unit plan, lesson plans, and full unit materials. These include classroom and online activities, assessments, and templates for future unit and lesson planning. Additional supplemental materials are provided to support Elementary Education and Sonography students and program advisors and also further promote the reframed unit materials and design

Absence of Doppler signal in transcranial color-coded ultrasonography may be confirmatory for brain death: A case report

Directory of Open Access Journals (Sweden)

Mehmet Akif Topçuoğlu

2015-08-01

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.

Re-Appraising the Role of Sonography in Pediatric Acute Abdominal Pain

OpenAIRE

Lin, Wei-Ching; Lin, Chien-Heng

2013-01-01

Objective Most pediatric emergency department (ED) visits are due to acute abdominal pain. Sonography is a reliable technique for differential diagnosis. The objective of this study was to re-appraise the role of sonography in evaluating acute abdominal pain in children. Methods Retrospective chart review of children aged

Malignant and benign diseases of the breast in 41 male patients: mammography, sonography and pathological correlations; Maligne und benigne Erkrankungen der Brust bei 41 maennlichen Patienten: Mammographie und Sonographie mit histopathologischer Korrelation

Energy Technology Data Exchange (ETDEWEB)

Partik, B.; Mallek, R.; Pokieser, P.; Wunderbaldinger, P.; Helbich, T.H. [Vienna Univ. (Austria). Klinik fuer Radiodiagnostik; Rudas, M. [Vienna Univ. (Austria). Inst. fuer Klinische Pathologie

2001-11-01

Aim: The goal of our study was to evaluate findings in mammography and sonography in male patients with pathohistologically proven diseases of the breast. Material and Methods: Mammographies and sonographies, which were obtained in 41 male patients in a 6-year period, were retrospectively evaluated in accordance with the BI-RADS trademark classification. Results: Histologically 13 carcinomas, 21 gynecomastias, 3 pseudogynecomastias, 2 epithelial inclusion cysts and 2 other benign lesions were diagnosed. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of mammography in differentiation of benign versus malignant disease were 92%, 89%, 80%, 96% and 90%, respectively. Additional sonography did not change these results. However, sonography increased diagnostic confidence in 18.2% (2/11) of suspicious lesions. Conclusion: In our study the invasive ductal carcinoma of male patients was a predominantly lobulated, ill-defined lesion in mammography and sonography. The differentiation of carcinoma to pseudogynecomastia and diffuse or dendritic gynecomastia was securely feasible. However, we could not reliably distinguish between carcinoma and some benign mass lesions. In cases of mammographically diagnosed masses or unclear mammography, additional sonography should be performed to increase the diagnostic confidence. (orig.) [German] Ziel: Die Befunde von Mammographie und Sonographie bei histologisch gesicherten malignen und benignen Mammaerkrankungen maennlicher Patienten zu evaluieren. Material und Methode: Retrospektiv wurden die in einem Zeitraum von 6 Jahren durchgefuehrten Mammographien und Sonographien bei 41 maennlichen Patienten in Anlehnung an die BI-RADS trademark Klassifikation ausgewertet. Resultate: Es wurden 13 Karzinome, 21 Gynaekomastien, 3 Pseudogynaekomastien, 2 Atherome und 2 weitere benigne Laesionen histologisch diagnostiziert. Die Mammographie zeigte in der Differenzierung maligne versus benigne Laesion

Comparison of CT scan and colour flow doppler ultrasound in detecting venous tumour thrombous in renal cell carcinoma

International Nuclear Information System (INIS)

Khan, A.R.; Anwar, K.

2008-01-01

Renal cell carcinoma has marked tendency to spread into renal vein, inferior vena cava and right side of heart. Extension of tumour thrombus into these veins will alter the surgical approach. We have compared the CT scan with Colour flow Doppler ultrasound in detecting venous tumour thrombus in renal vein and inferior vena cava. This cross-sectional study included 30 adult patients presenting with renal tumour. Patients of either gender were included in the study. Non probability convenience sampling was used. All patients underwent colour flow Doppler ultrasound and CT scan with contrast to asses the renal vein and inferior vena cava. The results were confirmed by intra operative findings and histopathology. The data was analyzed using SPSS version 12. Out of 30 patients, 20 (66%) were males and 10 (34%) female. The tumour was predominantly on the right side (60%), as was renal venous tumour thrombus (44%). Inferior vena cava was involved in 4 cases predominantly due to right sided tumours. The sensitivity of Doppler ultrasound in detecting renal venous tumour thrombus (88% on right and 100% on left side) was higher than CT scan (63% on right and 60% on left side). Doppler ultrasound was also superior to CT scan in detecting vena caval thrombus. The overall sensitivity of Doppler sonography was higher than CT scan in detecting tumour extension into renal veins and inferior vena cava. Therefore, it can be used as a complementary tool in equivocal cases. (author)

The role of sonography in the diagnosis of Echinococcus alveolaris

International Nuclear Information System (INIS)

Maier, W.

1983-01-01

Abdominal sonography and computed tomography were performed in eleven patients with operatively and histologically proven Echinococcus alveolaris of the liver and the detailed appearances were compared. Sonography is a useful screening method in the assessment of E. alveolaris, but its previous importance is being gradually superseded by computed tomography, which is capable of providing more detailed information in the diagnosis of Echinococcus infestation. (orig.)

Numerical stud of glare spot phase Doppler anemometry

OpenAIRE

Hespel , Camille; Ren , Kuan Fang; Gréhan , Gérard; Onofri , Fabrice

2008-01-01

International audience; The phase Doppler anemometry has (PDA) been developed to measure simultaneously the velocity and the size of droplets. When the concentration of particles is high, tightly focused beams must be used, as in the dual burst PDA. The latter permits an access to the refractive index of the particle, but the effect of wave front curvature of the incident beams becomes evident. In this paper, we introduce a glare spot phase Doppler anemometry which uses two large beams. The i...

Change of sonographic findings on cervical lymph nodes before and after preoperative radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Chikui, Toru; Yuasa, Kenji; Tokumori, Kenji; Kanda, Shigenobu [Department of Oral and Maxillofacial Radiology, Graduate School of Dental Science, 3-1-1 Maidashi Higashi-ku, 812-8582, Fukuoka (Japan); Kunitake, Naonobu; Nakamura, Katsumasa [Department of Clinical Radiology, Graduate School of Medical Science, Kyushu University, Fukuoka (Japan); Nagata, Tetsuji [First Department of Oral and Maxillofacial Surgery, Graduate School of Dental Science, Kyushu University, Fukuoka (Japan); Hiraki, Akimitsu [Second Department of Oral and Maxillofacial Surgery, Graduate School of Dental Science, Kyushu University, Fukuoka (Japan)

2004-07-01

The aim of this study was to assess the changes in the power Doppler sonographic findings in patients with oral cancer undergoing chemotherapy and radiotherapy. We performed US examinations on 187 cervical lymph nodes (71 metastatic and 116 reactive nodes) excised from 52 patients before and after preoperative therapy. On Power Doppler images, we calculated the vascular index (VI) and evaluated the vascular pattern. We also assessed the diagnostic power using receiver operating characteristic (ROC) curve analysis. Irradiation caused an increase of the VI and better visualization of the vessels within the lymph node in the reactive nodes; however, in the metastatic nodes, the VI was not significantly different between that before and after irradiation. When the reader observed the images before irradiation, the area under an ROC curve (Az values) observed by B-mode sonography were closely similar to those obtained by B-mode plus power Doppler sonography. With both images before and after irradiation, the Az value obtained by B-mode plus power Doppler sonography was higher than that by B-mode sonography alone. After irradiation, the enhanced Doppler signals contributed to a better visualization of the vessels and a better detection of any vascular abnormalities. (orig.)

Usefulness of B-mode and doppler sonography for the diagnosis of severe acute viral hepatitis A.

Science.gov (United States)

Shin, Sang Wook; Kim, Tae Yeob; Jeong, Woo Kyoung; Kim, Yongsoo; Kim, Jinoo; Kim, Young Hwan; Park, Hwan Cheol; Sohn, Joo Hyun

2015-01-01

To investigate B-mode and Doppler ultrasonography (US) features correlating with laboratory findings for the diagnosis of severe acute hepatitis (SAH) in patients with hepatitis A virus infection. Thirty-nine consecutive serologically proven patients were enrolled. Decreased parenchymal echotexture, periportal tracking, gallbladder wall change, and splenomegaly were assessed on B-mode images. Blood flow velocities were measured in the main portal (V(PORTAL)) and in the hepatic veins, and the hepatic venous pulsatility index was calculated. SAH was defined as high model for end-stage liver disease (MELD) score ≥ 15 with or without coagulopathy. The relationship between US features and laboratory findings was assessed, and SAH diagnosis was evaluated. Serum alanine transaminase and prothrombin time were significantly different depending on the presence of gallbladder wall change and splenomegaly (p hepatic venous waveform and hepatic venous pulsatility index were significantly correlated with MELD score. For the diagnosis of SAH, the area under the receiver operating characteristic curve of V(PORTAL) was 0.798. It reached 0.869 in the patients with typical GB change. Both B-mode and Doppler US correlated well with several laboratory variables and may be helpful to diagnose SAH in patients with hepatitis A virus infection. © 2014 Wiley Periodicals, Inc.

Performance evaluation of an all-fiber image-reject homodyne coherent Doppler wind lidar

DEFF Research Database (Denmark)

Abari, Cyrus F.; Pedersen, Anders Tegtmeier; Dellwik, Ebba

2015-01-01

The main purpose of this study is to evaluate the near-zero wind velocity measurement performance of two separate 1.5 µm all-fiber coherent Doppler lidars (CDLs). The performance characterization is carried out through the presentation of the results from two separate atmospheric field campaigns....... In one campaign, a recently developed continuous wave (CW) CDL benefiting from an image-reject front-end was deployed. The other campaign utilized a different CW CDL, benefiting from a heterodyne receiver with intermediate-frequency (IF) sampling. In both field campaigns the results are compared against...

Determination of testicular blood flow in camelids using vascular casting and color pulsed-wave Doppler ultrasonography.

Science.gov (United States)

Kutzler, Michelle; Tyson, Reid; Grimes, Monica; Timm, Karen

2011-01-01

We describe the vasculature of the camelid testis using plastic casting. We also use color pulsed-wave Doppler ultrasonography to measure testicular blood flow and compare the differences between testicular blood flow in fertile and infertile camelids. The testicular artery originates from the ventral surface of the aorta, gives rise to an epididymal branch, and becomes very tortuous as it approaches the testis. Within the supratesticular arteries, peak systolic velocity (PSV) was higher in fertile males compared to infertile males (P = 0.0004). In addition, end diastolic velocity (EDV) within the supratesticular arteries was higher for fertile males when compared to infertile males (P = 0.0325). Within the marginal arteries, PSV was also higher in fertile males compared to infertile males (P = 0.0104). However, EDV within the marginal arteries was not significantly different between fertile and infertile males (P = 0.121). In addition, the resistance index was not significantly different between fertile and infertile males within the supratesticular (P = 0.486) and marginal arteries (P = 0.144). The significance of this research is that in addition to information obtained from a complete reproductive evaluation, a male camelid's fertility can be determined using testicular blood flow measured by Doppler ultrasonography.

Determination of Testicular Blood Flow in Camelids Using Vascular Casting and Color Pulsed-Wave Doppler Ultrasonography

Directory of Open Access Journals (Sweden)

Michelle Kutzler

2011-01-01

Full Text Available We describe the vasculature of the camelid testis using plastic casting. We also use color pulsed-wave Doppler ultrasonography to measure testicular blood flow and compare the differences between testicular blood flow in fertile and infertile camelids. The testicular artery originates from the ventral surface of the aorta, gives rise to an epididymal branch, and becomes very tortuous as it approaches the testis. Within the supratesticular arteries, peak systolic velocity (PSV was higher in fertile males compared to infertile males (P=0.0004. In addition, end diastolic velocity (EDV within the supratesticular arteries was higher for fertile males when compared to infertile males (P=0.0325. Within the marginal arteries, PSV was also higher in fertile males compared to infertile males (P=0.0104. However, EDV within the marginal arteries was not significantly different between fertile and infertile males (P=0.121. In addition, the resistance index was not significantly different between fertile and infertile males within the supratesticular (P=0.486 and marginal arteries (P=0.144. The significance of this research is that in addition to information obtained from a complete reproductive evaluation, a male camelid's fertility can be determined using testicular blood flow measured by Doppler ultrasonography.

Remote Sensing of Aerosol Backscatter and Earth Surface Targets By Use of An Airborne Focused Continuous Wave CO2 Doppler Lidar Over Western North America

Science.gov (United States)

Jarzembski, Maurice A.; Srivastava, Vandana; Goodman, H. Michael (Technical Monitor)

2000-01-01

Airborne lidar systems are used to determine wind velocity and to measure aerosol or cloud backscatter variability. Atmospheric aerosols, being affected by local and regional sources, show tremendous variability. Continuous wave (cw) lidar can obtain detailed aerosol loading with unprecedented high resolution (3 sec) and sensitivity (1 mg/cubic meter) as was done during the 1995 NASA Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS) mission over western North America and the Pacific Ocean. Backscatter variability was measured at a 9.1 micron wavelength cw focused CO2 Doppler lidar for approximately 52 flight hours, covering an equivalent horizontal distance of approximately 30,000 km in the troposphere. Some quasi-vertical backscatter profiles were also obtained during various ascents and descents at altitudes that ranged from approximately 0.1 to 12 km. Similarities and differences for aerosol loading over land and ocean were observed. Mid-tropospheric aerosol backscatter background mode was approximately 6 x 10(exp -11)/ms/r, consistent with previous lidar datasets. While these atmospheric measurements were made, the lidar also retrieved a distinct backscatter signal from the Earth's surface from the unfocused part of the focused cw lidar beam during aircraft rolls. Atmospheric backscatter can be highly variable both spatially and temporally, whereas, Earth-surface backscatter is relatively much less variant and can be quite predictable. Therefore, routine atmospheric backscatter measurements by an airborne lidar also give Earth surface backscatter which can allow for investigating the Earth terrain. In the case where the Earth's surface backscatter is coming from a well-known and fairly uniform region, then it can potentially offer lidar calibration opportunities during flight. These Earth surface measurements over varying Californian terrain during the mission were compared with laboratory backscatter measurements using the same lidar of various

Using modern teaching strategies to teach upper abdominal sonography to medical students.

Science.gov (United States)

Cheng, Wei-Chun; Lin, Xi-Zhang; Chen, Chiung-Yu

2013-07-01

Upper abdominal sonography can help physicians to confirm the diagnosis of various hepatobiliary diseases. Teaching sonography skills to medical students is important because it may enhance their level of knowledge and overall development during their gastroenterology section rotation. Sonographic imaging is abstract and students can be easily confused when scanning the abdominal structures from different sites and directions. We used several modern teaching strategies to facilitate the learning of sonography skills. The year five medical students beginning a gastroenterology section rotation for their first-year clerkship were taught abdominal sonography skills. Abstract sonographic images were related to concrete objects and the surrounding structures were further indicated. Each of the images was given a specific name and was sorted according to the scanning site. A mnemonics system was designed to help students to memorize the names of these images. A badge was created to recognize the achievement of being able to complete a basic upper abdominal sonography. Students were free (i.e., not obligated) to request a demonstration opportunity to show their skills within 2 weeks after receiving tutelage. We recorded the number of students who received training and were able to successfully complete the task; these individuals then received a badge to be pinned onto their white coats. Sixty-three of 68 students (92.6%) requested evaluation and all of them passed. We have greatly simplified the process of learning about upper abdominal sonography by using andragogy to enhance learning, mnemonics to help memory, and a pin-badge reward system to stimulate incentives. Copyright © 2013. Published by Elsevier B.V.

Biopsy guided by real-time sonography fused with MRI: a phantom study

DEFF Research Database (Denmark)

Ewertsen, C.; Grossjohann, Hanne Sønder; Nielsen, Kristina Rue

2008-01-01

OBJECTIVE: The purpose of our study was to test the accuracy of sonographically guided biopsies in a phantom of structures not visible on sonography but shown on MRI by using commercially available sonography systems with image fusion software. MATERIALS AND METHODS: A previously recorded MRI...

Duplex sonography of the near-surface leg veins; Duplexsonographie der oberflaechlichen Beinvenen

Energy Technology Data Exchange (ETDEWEB)

Mendoza, E.

2007-07-01

The book contains the following contributions: The ultrasonograph, selection of the ultrasonic transducer, anatomy of the near-surface vein system, physiology of the near-surface vein system, varicose status classification, systematics of the duplex sonography of near-surface leg veins, provocational maneuver for the duplex sonographic varicose diagnostics, exploration of vena saphena parva, perforans veins, side branches, phlebitis, sonography for varicose therapy, postsurgical sonography, deep leg veins, examination of near-surface leg veins for the pathology of the deep vein system, differential diagnostic clarification of leg oedema from the phlebologic-lymphological view, diagnostic side features along the near-surface leg veins.

The demonstration of gall stones by sonography and radiography

International Nuclear Information System (INIS)

Gladisch, R.; Deininger, H.K.; Staedtische Kliniken Darmstadt

1983-01-01

Eighty-seven unselected gall stones were examined radiologically and by ultrasound in vitro. No relationship of diagnostic value could be established between the amount of calcification and stone demonstration, the sonogram being influenced by the size of the stone, its surface contour and its position in the ultrasound beam. Sonography is therefore not suitable for selecting those patients on whom litholysis could be carried out. Sonography appears to be useful only in a negative way by establishing the exact size of the concretion. (orig.) [de

Pulsed-wave tissue Doppler imaging of the myocardium of cats with induced thyrotoxicosis Doppler tecidual pulsado do miocárdio de gatos com tirotoxicose induzida

Directory of Open Access Journals (Sweden)

Daniel Capucho de Oliveira

2011-06-01

Full Text Available Left ventricular myocardial motion was quantified using pulsed-wave tissue Doppler imaging (PW-TDI in nine adult cats before and after thyrotoxicosis induction. In order to induce thyrotoxicosis, all cats were given 150µg kg-1 of levothyroxine sodium as a single oral dose each day for 10 weeks. PW-TDI examinations were performed immediately before the induction and by the end of the experimental protocol. An increase in myocardial motion velocity was documented at the interventricular septum level, demonstrated by an elevation in systolic (Sa, and early (Ea and late (Aa diastolic waves (PA velocidade de movimentação miocárdica do ventrículo esquerdo foi quantificada por meio de exames ecocardiográficos com Doppler tecidual pulsado (PW-TDI em nove gatos adultos antes e após indução à tirotoxicose. Para indução da tirotoxicose, todos os gatos receberam doses diárias de 150mg kg-1 de levotiroxina sódica, por via oral, durante 10 semanas. Os exames de PW-TDI foram realizados imediatamente antes da indução e ao final do protocolo experimental. Uma elevação na velocidade de movimentação miocárdica foi documentada ao nível do septo interventricular, demonstrado por um aumento das ondas sistólica (Sa e diastólicas (Ea e Aa; P<0,05. No entanto, nenhuma alteração nos valores de Sa, Ea e Aa foi encontrada ao nível da parede livre do ventrículo esquerdo. A frequência cardíaca aumentou significativamente entre os momentos experimentais, sendo que três animais apresentaram fusão das ondas Aa e Ea ao final do experimento. O protocolo experimental utilizado neste estudo causou alterações na velocidade de movimentação do miocárdio ventricular esquerdo, mas sem causar danos à função diastólica do ventrículo esquerdo.

Radiology of the male breast. Radiologische Diagnostik der maennlichen Brustdruese. Mammographie, Sonographie, pathohistologische Korrelation

Energy Technology Data Exchange (ETDEWEB)

Buchberger, W; Penz, T; Strasser, K [Innsbruck Univ. (Austria). Universitaetsklinik fuer Radiodiagnostik; Toetsch, M [Innsbruck Univ. (Austria). Inst. fuer Pathologische Anatomie

1991-09-01

61 men with breast enlargement underwent mammography; complementary sonography was performed in 34 cases. Diagnoses included gynaecomastia in 53 cases, pseudogynaecomastia in 9 cases, 3 carcinomas, 2 inflammatory lesions and 1 lipoma. Mammography and sonography can differentiate reliably true gynaecomastia from pseudogynaecomastia. Gynaecomastia and especially inflammatory lesions may not always be readily differentiated from carcinoma. Sonography can be helpful by demonstrating hyperreflexive glandular tissue, whereas carcinomas are usually hypoechoic. (orig./GDG).

The accuracy of chest sonography in the diagnosis of small pleural effusion

International Nuclear Information System (INIS)

Kocijancic, I.

2003-01-01

Background. The aim of the study was to evaluate the accuracy of chest sonography in the radiological diagnosis of small pleural effusions. Patients and methods. Patients referred for abdominal and/or chest sonographies for various reasons were examined for sonographic features of pleural effusion. From January 1997 till January 2000, 69 patients were included into the study. Fifty-two patients were found to have pleural effusion not exceeding 15 mm in depth, the rest of them served as controls. Subsequently erect posteroanterior and expiratory lateral decubitus projections were done in all patients. Results. Compared to radiological examination chest sonography had a positive predictive value of 92% in the diagnosis of small pleural effusions in our study population. The mean thickness of fluid was 9.2 mm on ultrasonography and 7.6 mm on expiratory lateral decubitus views (P<0.01). Conclusions. Chest sonography showed a high degree of accuracy for demonstrating small pleural effusions and could replace lateral decubitus chest radiographs adequately. (author)

Diagnosis of hydronephrosis: comparison of radionuclide scanning and sonography

International Nuclear Information System (INIS)

Malave, S.R.; Neiman, H.L.; Spies, S.M.; Cisternino, S.J.; Adamo, G.

1980-01-01

Diagnostic sonographic and radioisotope scanning techniques have been shown to be useful in the diagnosis of obstructive uropathy. The accuracy of both methods was compared and sonography was found to provide the more accurate data (sensitivity, 90%, specificity, 98%; accuracy, 97%). Sonography provides excellent anatomic information and enables one to grade the degree of dilatation. Renal radionuclide studies were less sensitive in detecting obstruction, particularly in the presence of chronic renal disease, but offered additional information regarding relative renal blood flow, total effective renal plasma flow, and interval change in renal parenchymal function

An economic evaluation of first-trimester genetic sonography for prenatal detection of Down syndrome.

Science.gov (United States)

Vintzileos, A M; Ananth, C V; Fisher, A J; Smulian, J C; Day-Salvatore, D; Beazoglou, T

1998-04-01

To determine 1) the diagnostic accuracy requirements of first-trimester genetic sonography from the cost-benefit point of view and 2) the economic impact of first-trimester genetic sonography for the United States on the basis of the accuracy of previously published studies. A cost-benefit equation was developed on the basis of the hypothesis that the cost of chorionic villus sampling (CVS) in pregnant women with advanced maternal age (at least 35 years old) should be at least equal to the cost of genetic sonography with CVS used only for those with abnormal ultrasound results. The components of the equation included the diagnostic accuracy of genetic ultrasound (sensitivity and specificity for detecting Down syndrome), the costs of the CVS package and genetic ultrasound, and the lifetime cost of Down syndrome cases. First-trimester genetic sonography was found to be beneficial if the overall sensitivity for detecting Down syndrome was greater than 70%, and even then, the cost-benefit ratio depended on the corresponding false-positive rate. The required minimum ultrasound sensitivity varied according to the maternal age-specific prevalence of Down syndrome and ranged between 40% (for women 35 years old) to 96% (for women 44 years old). Of eight published cohorts using nuchal translucency thickness for genetic sonography, five had accuracies of genetic ultrasound compatible with net benefits. The benefits of first-trimester genetic sonography depend on its diagnostic accuracy. First-trimester genetic sonography has the potential for annual savings of 22 million dollars in the United States.

Vascularity and grey-scale sonographic features of normal cervical lymph nodes: variations with nodal size

International Nuclear Information System (INIS)

Ying, Michael; Ahuja, Anil; Brook, Fiona; Metreweli, Constantine

2001-01-01

AIM: This study was undertaken to investigate variations in the vascularity and grey-scale sonographic features of cervical lymph nodes with their size. MATERIALS AND METHODS: High resolution grey-scale sonography and power Doppler sonography were performed in 1133 cervical nodes in 109 volunteers who had a sonographic examination of the neck. Standardized parameters were used in power Doppler sonography. RESULTS: About 90% of lymph nodes with a maximum transverse diameter greater than 5 mm showed vascularity and an echogenic hilus. Smaller nodes were less likely to show vascularity and an echogenic hilus. As the size of the lymph nodes increased, the intranodal blood flow velocity increased significantly (P 0.05). CONCLUSIONS: The findings provide a baseline for grey-scale and power Doppler sonography of normal cervical lymph nodes. Sonologists will find varying vascularity and grey-scale appearances when encountering nodes of different sizes. Ying, M. et al. (2001)

The Role of Color Doppler Ultrasonography in Characterization of Thyroid Tumors

International Nuclear Information System (INIS)

Kim, Hee Soo; Jeon, Pyong; Won, Jong Yoon; Na, Jae Beom; Lee, Hyang Mee; Yoo, Hyung Sik; Lee, Jong Tae; Park, Jeong Soo; Cho, Nam Hoon

1995-01-01

To assess the usefulness of color Doppler ultrasonography in the characterization of thyroid tumors, surgically proven 88 nodules in 85 patients were evaluated. Using 10 MHz linear array transducer, gray scale images were initially evaluated. Then, distribution pattern of color signals (marginal, intra-tumoral, mixed) and graded internal vascularity according to morphology of color signal (0:absence of internal signal, 1: spotty, 2: linear,3: branching) were observed on color doppler imaging. Pulsed doppler waves were analyzed with parameters including peak systolic velocity(PSV), resistive index(RI), and pulsatile index(PI). Significantly larger numbers of intra-tumoral type, 20 cases(62.5%), were observed in malignant nodules, whereas mixed forms were predominant in benign group, 37 cases (66%) In graded internal vascularity, malignant nodules tended to have grade 2 or 3 signals, whereas benign nodules tended to have grade 0 or 1 signals. Spectral wave analysis show no significant difference in the value of PSV, RI, and PI between malignancy and benignity group. In conclusion, color Doppler imaging has a potential role in the characterization of thyroid nodules as a supportive method for gray scale diagnosis

Coherent Detection in Laser Doppler Velocimeters

DEFF Research Database (Denmark)

Hanson, Steen Grüner

1974-01-01

, but intelligible particle picture of electromagnetic waves. The analysis is carried out with special emphasis on the heterodyning process in the laser Doppler velocimeter (LDV) because the main purpose of this article is to provide a better understanding of this instrument. An aid for this purpose......The possibility of heterodyning between electromagnetic waves scattered by particles separated in space is explained from a classical point of view and from a quantum mechanical point of view. The last description being carried out using only the Heisenberg uncertainty principle and a rather coarse...

Women's perception of transvaginal sonography in a tertiary hospital in nigeria

International Nuclear Information System (INIS)

Eze, C.U.; Okaro, A.O.; Nwobi, I.C.

2008-01-01

Available studies suggest that pregnant women's views on the desirability of routine ultrasound are Influenced by their perceptions of its potential benefits and concern about possible adverse effects. To assess women's views of transvaginal sonography and to determine any correlation between their perception of the procedure and their prior knowledge and experience of it. We surveyed women presenting with various gynecologic problems or complications of the first trimester. Data collection was by self-administered questionnaires using conveniences sampling technique on women attending the clinic over a period of one year. Only women who had transvaginal sonography were included. A total of 250 women were recruited and interviewed. Transvaginal sonography was considered not embarrassing by 76%, acceptable by 86%, not painful by 87.2% and not stressful by 82% of the women. There were no statistically significant differences in the women's perception of the procedure whether they had prior knowledge and previous experience of the procedure or not (P>0.05). The majority of the women perceived transvaginal sonography favourably. Their perception of the Procedure was favourable whether they had prior knowledge and previous experience of it or not. (author)

Radiological evaluation with Doppler sonography and multidetector CT angiography in congenital hepatic arteriovenous malformation in a newborn

Energy Technology Data Exchange (ETDEWEB)

Adaletli, Ibrahim; Kurugoglu, Sebuh; Kilic, Fahrettin [Istanbul University, Department of Radiology, Cerrahpasa Medical Faculty (Turkey); Senyuz, Osman F. [Istanbul University, Department of Paediatric Surgery, Cerrahpasa Medical Faculty (Turkey); Dervisoglu, Sergulen [Istanbul University, Department of Pathology, Cerrahpasa Medical Faculty (Turkey)

2006-11-15

Although hepatic arteriovenous malformations are rarely reported, they frequently have life-threatening complications such as cardiac failure and are associated with a high mortality rate. Consequently, accurate prenatal and early postnatal diagnosis is important and therapeutic procedures depend on the imaging features. We report the early postnatal sonographic, Doppler sonographic, multidetector CT and CT angiography findings of a congenital hepatic arteriovenous malformation in a newborn. (orig.)

Radiological evaluation with Doppler sonography and multidetector CT angiography in congenital hepatic arteriovenous malformation in a newborn

International Nuclear Information System (INIS)

Adaletli, Ibrahim; Kurugoglu, Sebuh; Kilic, Fahrettin; Senyuz, Osman F.; Dervisoglu, Sergulen

2006-01-01

Although hepatic arteriovenous malformations are rarely reported, they frequently have life-threatening complications such as cardiac failure and are associated with a high mortality rate. Consequently, accurate prenatal and early postnatal diagnosis is important and therapeutic procedures depend on the imaging features. We report the early postnatal sonographic, Doppler sonographic, multidetector CT and CT angiography findings of a congenital hepatic arteriovenous malformation in a newborn. (orig.)

Deginerative changes of femoral articular cartilage in the knee : comparative study of specimen sonography and pathology

International Nuclear Information System (INIS)

Park, Ju Youn; Hong, Sung Hwan; Sohn, Jin Hee; Wee, Young Hoon; Chang, Jun Dong; Park, Hong Seok; Lee, Eil Seoung; Kang Ik Won

2001-01-01

To determine the sonographic findings of degenerative change in femoral articular cartilage of the knee by comparative study of specimen sonography and pathology. We obtained 40 specimens of cartilage of the femur (20 medial and 20 lateral condylar) from 20 patients with osteoarthritis of the knee who had undergone total knee replacement. The specimens were placed in a saline-filled container and sonography was performed using a 10-MHz linear transducer. Sonographic abnormalities were evaluated at the cartilage surface, within the cartilage, and at the bone-cartilage interface, and were compared with the corresponding pathologic findings. In addition, cartilage thickness was measured at a representative portion of each femoral cartilage specimen and was compared with the thickness determined by sonography. 'Dot' lesions, irregularity or loss of the hyperechoic line, were demonstrated by sonography at the saline-cartilage interface of 14 cartilages. Pathologic examination showed that these findings corresponded to cleft, detachment, erosion, and degeneration. Irregularities in the hyperechoic line at the bone-cartilage interface were revealed by sonography in eight cartilages and were related to irregularity or loss of tidemark, downward displacement of the cartilage, and subchondral callus formation. Dot lesions, corresponding to cleft and degeneration, were noted within one cartilage. Cartilage thickness measured on specimen and by sonography showed no significant difference (p=0.446). Specimen sonography suggested that articular cartilage underwent degenerative histopathological change. Cartilage thickness measured by sonography exactly reflected real thickness

Color M-mode and pulsed wave tissue Doppler echocardiography

DEFF Research Database (Denmark)

Møller, J E; Søndergaard, E; Poulsen, S H

2001-01-01

To assess the association between color M-mode flow propagation velocity and the early diastolic mitral annular velocity (E(m)) obtained with tissue Doppler echocardiography and to assess the prognostic implications of the indexes, echocardiography was performed on days 1 and 5, and 1 and 3 month...

EPILEPTIC ENCEPHALOPATHY WITH CONTINUOUS SPIKES-WAVES ACTIVITY DURING SLEEP

Directory of Open Access Journals (Sweden)

E. D. Belousova

2012-01-01

Full Text Available The author represents the review and discussion of current scientific literature devoted to epileptic encephalopathy with continuous spikes-waves activity during sleep — the special form of partly reversible age-dependent epileptic encephalopathy, characterized by triad of symptoms: continuous prolonged epileptiform (spike-wave activity on EEG in sleep, epileptic seizures and cognitive disorders. The author describes the aspects of classification, pathogenesis and etiology, prevalence, clinical picture and diagnostics of this disorder, including the peculiar anomalies on EEG. The especial attention is given to approaches to the treatment of epileptic encephalopathy with continuous spikeswaves activity during sleep. Efficacy of valproates, corticosteroid hormones and antiepileptic drugs of other groups is considered. The author represents own experience of treatment this disorder with corticosteroids, scheme of therapy and assessment of efficacy.

Cerebral Hemodynamics in the Elderly: A Transcranial Doppler Study in the Einstein Aging Study Cohort.

Science.gov (United States)

Yang, Dixon; Cabral, Digna; Gaspard, Emmanuel N; Lipton, Richard B; Rundek, Tatjana; Derby, Carol A

2016-09-01

We sought to describe the relationship between age, sex, and race/ethnicity with transcranial Doppler hemodynamic characteristics from major intracerebral arterial segments in a large elderly population with varying demographics. We analyzed 369 stroke-free participants aged 70 years and older from the Einstein Aging Study. Single-gate, nonimaging transcranial Doppler sonography, a noninvasive sonographic technique that assesses real-time cerebrovascular hemodynamics, was used to interrogate 9 cerebral arterial segments. Individual Doppler spectra and cerebral blood flow velocities were acquired, and the pulsatility index and resistive index were calculated by the device's automated waveform-tracking function. Multiple linear regression models were used to examine the independent associations of age, sex, and race/ethnicity with transcranial Doppler measures, adjusting for hypertension, history of myocardial infarction or revascularization, and history of diabetes. Among enrolled participants, 303 individuals had at least 1 vessel insonated (mean age [SD], 80 [6] years; 63% women; 58% white; and 32% black). With age, transcranial Doppler measures of mean blood flow velocity were significantly decreased in the basilar artery (P = .001) and posterior cerebral artery (right, P = .003; left, P = .02). Pulsatility indices increased in the left middle cerebral artery (P = .01) and left anterior cerebral artery (P = .03), and the resistive index was increased in the left middle cerebral artery (P = .007) with age. Women had higher pulsatility and resistive indices compared to men in several vessels. We report a decreased mean blood flow velocity and weakly increased arterial pulsatility and resistance with aging in a large elderly stroke-free population. These referential trends in cerebrovascular hemodynamics may carry important implications in vascular diseases associated with advanced age, increased risk of cerebrovascular disease, cognitive decline, and dementia.

Sonography as a new diagnostic procedure for investigating abnormalities of the shoulder

International Nuclear Information System (INIS)

Rapf, C.; Furtschegger, A.; Resch, H.; Innsbruck Univ.

1986-01-01

Eighty-one sonographic examinations of patients with complaints relating to the shoulder joint have shown that this is the method next in value to radiological examination. So far, lesions of the rotator cuff and of the long head of the biceps could only be demonstrated by invasive procedures such as arthrography or arthroscopy. In these situations, sonography attains a similar accuracy. Diffuse lesions can also be diagnosed correctly, making arthrography and arthroscopy unnecessary. In addition, sonography can demonstrate inflammatory and degenerative changes and incomplete sub-acromial and intermediary tears of the rotator cuff, unlike conventional diagnostic methods. In future, arthrography and arthroscopy will only be necessary as additional diagnostic methods if sonography remains inconclusive. (orig.) [de

Stress Urinary lncontinence : Comparative Study of Perineal Sonography in Erect Position and Chain Cystourethrograpy

Energy Technology Data Exchange (ETDEWEB)

Han, Gi Seok; Kim, Seung Hyup; Yeon, Kyung Mo; Han, Man Chung; Paick, Jae Seung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

1995-06-15

Authors investigated the diagnostic value of perineal sonography in erect position for patients with stress urinary incontinence. Perineal sonography and chain cystourethrography were performed in 18 female patients(mean age 51.2) with stress urinary incontinence. The posterior are throvesical angles in stress and rest states were measured in both studies and compared with each other. Mean posteriorurethrovesical angles({+-}2 standard error) in rest and stress states were 136.3({+-}7.2) .deg. , and 145.9({+-}7.0) .deg. for chain cystourethrography and 131.4({+-}5.6) .deg. and 143.4({+-}5.9) .deg. for perineal sonography, respectively. The data frorm both studies correlated well with cach other. Perineal sonography inerect position is easy,non-invasive technique and may substitute the chain cystourethrography in the evaluation of the patients with stress urinary in continece

Retrobulbar Hematoma from Warfarin Toxicity and the Limitations of Bedside Ocular Sonography

Science.gov (United States)

2010-05-01

worldwide. Peer Reviewed Title: Retrobulbar Hematoma from Warfarin Toxicity and the Limitations of Bedside Ocular Sonography Journal Issue: Western...Preferred Citation: Thompson D, Stanescu C, Pryor P, Laselle B. Retrobulbar Hematoma from Warfarin Toxicity and the Limitations of Bedside Ocular...nontrauamtic retrobulbar hematoma associated with warfarin toxicity. The application and limitations of focused bedside ocular sonography for this

Joint positions matter for ultrasound examination of RA patients-increased power Doppler signal in neutral versus flat position of hands.

Science.gov (United States)

Husic, Rusmir; Lackner, Angelika; Stradner, Martin H; Hermann, Josef; Dejaco, Christian

2017-08-01

Position of joints might influence the result of US examination in patients with RA. The purpose of this work was to compare grey-scale (GS) and power Doppler (PWD) findings obtained in neutral vs flat position of hands. A cross-sectional study of 42 RA patients with active disease. Two dimensional and 3D sonography of wrists and MCP joints were conducted in two different joint positions: neutral position, which is a slight flexion of the fingers with relaxed extensor muscles; and flat position, where all palm and volar sides of fingers touch the Table. Two dimensional GS synovitis (GSS) and PWD signals were scored semi-quantitatively (0-3). For 3D sonography, the percentage of PWD voxels within a region of interest was calculated. GSS was not quantified using 3D sonography. Compared with neutral position, 2D PWD signals disappeared in 28.3% of joints upon flattening. The median global 2D PWD score (sum of all PWD scores of an individual patient) decreased from 8 to 3 ( P < 0.001), and the global 3D PWD voxel score from 3.8 to 0.9 ( P < 0.001). The reduction of PWD scores was similar in all joints (2D: minus 50%, 3D: minus 66.4-80.1%). Inter- and intrareader agreement of PWD results was good (intraclass correlation coefficient: 0.75-0.82). In RA, a neutral position of the hands is linked to a higher sensitivity of 2D and 3D sonography in detecting PWD signals at wrists and MCP joints, compared with a flat position. Standardization of the scanning procedure is essential for obtaining comparable US results in RA patients in trials and clinical routines. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Hough transform search for continuous gravitational waves

International Nuclear Information System (INIS)

Krishnan, Badri; Papa, Maria Alessandra; Sintes, Alicia M.; Schutz, Bernard F.; Frasca, Sergio; Palomba, Cristiano

2004-01-01

This paper describes an incoherent method to search for continuous gravitational waves based on the Hough transform, a well-known technique used for detecting patterns in digital images. We apply the Hough transform to detect patterns in the time-frequency plane of the data produced by an earth-based gravitational wave detector. Two different flavors of searches will be considered, depending on the type of input to the Hough transform: either Fourier transforms of the detector data or the output of a coherent matched-filtering type search. We present the technical details for implementing the Hough transform algorithm for both kinds of searches, their statistical properties, and their sensitivities

PMN-PT single crystal, high-frequency ultrasonic needle transducers for pulsed-wave Doppler application.

Science.gov (United States)

Zhou, Qifa; Xu, Xiaochen; Gottlieb, Emanuel J; Sun, Lei; Cannata, Jonathan M; Ameri, Hossein; Humayun, Mark S; Han, Pengdi; Shung, K Kirk

2007-03-01

High-frequency needle ultrasound transducers with an aperture size of 0.4 mm were fabricated using lead magnesium niobate-lead titanate (PMN-33% PT) as the active piezoelectric material. The active element was bonded to a conductive silver particle matching layer and a conductive epoxy backing through direct contact curing. An outer matching layer of parylene was formed by vapor deposition. The active element was housed within a polyimide tube and a 20-gauge needle housing. The magnitude and phase of the electrical impedance of the transducer were 47 omega and -38 degrees, respectively. The measured center frequency and -6 dB fractional bandwidth of the PMN-PT needle transducer were 44 MHz and 45%, respectively. The two-way insertion loss was approximately 15 dB. In vivo high-frequency, pulsed-wave Doppler patterns of blood flow in the posterior portion and in vitro ultrasonic backscatter microscope (UBM) images of the rabbit eye were obtained with the 44-MHz needle transducer.

Usefulness of high-resolution sonography in early diagnosis of rabbit clonorchiasis

International Nuclear Information System (INIS)

Lim, Jae Hoon; Choi, Don Gil; Chung, Il Gyu; Phyun, Lae Hyun; Pyeun, Yong Seon; Hong, Sung Tae; Lee, Me Jeong

1999-01-01

To determine the role of high-resolution sonography in the early diagnosis of experimentally induced clonorchiasis in rabbits. We performed sonographic examination weekly in 22 lightly-infected rabbits (10 rabbits infected with 10 metacercariae, 6 rabbits infected with 20 metacercariae, and 6 rabbits infected with 40 metacercariae), and 10 heavily-infected rabbits (500 metacercariae). The sonographic criterion of diagnosis with dilatation of the intrahepatic ducts. We sacrificed lightly-infected rabbits and counted numbers of adult worms of clonorchis sinensis 9 weeks after infection. Sonographic abnormalities were found 3 weeks after infection in 2 lightly-infected rabbits and 5 heavily-infected rabbits. On sonography at 9 weeks after infection, we observed dilatation of the intrahepatic ducts in 11 (65%) of 17 lightly-infected rabbits and all of 10 heavily-infected rabbits. High-resolution sonography is very useful in early diagnosis of rabbits clonorchiasis.

Usefulness of high-resolution sonography in early diagnosis of rabbit clonorchiasis

Energy Technology Data Exchange (ETDEWEB)

Lim, Jae Hoon; Choi, Don Gil; Chung, Il Gyu; Phyun, Lae Hyun; Pyeun, Yong Seon [Sungkyunkwan University College of Medicine, Seoul (Korea, Republic of); Hong, Sung Tae; Lee, Me Jeong [Seoul National University College of Medicine, Seoul (Korea, Republic of)

1999-09-15

To determine the role of high-resolution sonography in the early diagnosis of experimentally induced clonorchiasis in rabbits. We performed sonographic examination weekly in 22 lightly-infected rabbits (10 rabbits infected with 10 metacercariae, 6 rabbits infected with 20 metacercariae, and 6 rabbits infected with 40 metacercariae), and 10 heavily-infected rabbits (500 metacercariae). The sonographic criterion of diagnosis with dilatation of the intrahepatic ducts. We sacrificed lightly-infected rabbits and counted numbers of adult worms of clonorchis sinensis 9 weeks after infection. Sonographic abnormalities were found 3 weeks after infection in 2 lightly-infected rabbits and 5 heavily-infected rabbits. On sonography at 9 weeks after infection, we observed dilatation of the intrahepatic ducts in 11 (65%) of 17 lightly-infected rabbits and all of 10 heavily-infected rabbits. High-resolution sonography is very useful in early diagnosis of rabbits clonorchiasis.

Evaluation of ground stiffness parameters using continuous surface wave geophysics

DEFF Research Database (Denmark)

Gordon, Anne; Foged, Niels

2000-01-01

Present day knowledge of the magnitude of the strain levels in the ground associated with geotechnical structures, together with an increasing number of projects requiring the best estimates of ground movements around excavations, has led to, inter alia, increased interest in measuring the very......-small-strain stiffness of the ground Gmax. Continuous surface wave geophysics offers a quick, non-intrusive and economical way of making such measurements. This paper reviews the continuous surface wave techniques and evaluates, in engineering terms, the applicability of the method to the site investigation industry....

A Generalized Wave Diagram for Moving Sources

Science.gov (United States)

Alt, Robert; Wiley, Sam

2004-12-01

Many introductory physics texts1-5 accompany the discussion of the Doppler effect and the formation of shock waves with diagrams illustrating the effect of a source moving through an elastic medium. Typically these diagrams consist of a series of equally spaced dots, representing the location of the source at different times. These are surrounded by a series of successively smaller circles representing wave fronts (see Fig. 1). While such a diagram provides a clear illustration of the shock wave produced by a source moving at a speed greater than the wave speed, and also the resultant pattern when the source speed is less than the wave speed (the Doppler effect), the texts do not often show the details of the construction. As a result, the key connection between the relative distance traveled by the source and the distance traveled by the wave is not explicitly made. In this paper we describe an approach emphasizing this connection that we have found to be a useful classroom supplement to the usual text presentation. As shown in Fig. 2 and Fig. 3, the Doppler effect and the shock wave can be illustrated by diagrams generated by the construction that follows.

Stress Urinary lncontinence : Comparative Study of Perineal Sonography in Erect Position and Chain Cystourethrograpy

International Nuclear Information System (INIS)

Han, Gi Seok; Kim, Seung Hyup; Yeon, Kyung Mo; Han, Man Chung; Paick, Jae Seung

1995-01-01

Authors investigated the diagnostic value of perineal sonography in erect position for patients with stress urinary incontinence. Perineal sonography and chain cystourethrography were performed in 18 female patients(mean age 51.2) with stress urinary incontinence. The posterior are throvesical angles in stress and rest states were measured in both studies and compared with each other. Mean posteriorurethrovesical angles(±2 standard error) in rest and stress states were 136.3(±7.2) .deg. , and 145.9(±7.0) .deg. for chain cystourethrography and 131.4(±5.6) .deg. and 143.4(±5.9) .deg. for perineal sonography, respectively. The data frorm both studies correlated well with cach other. Perineal sonography inerect position is easy,non-invasive technique and may substitute the chain cystourethrography in the evaluation of the patients with stress urinary in continece

Frequency shift of the Bragg and Non-Bragg backscattering from periodic water wave

Science.gov (United States)

Wen, Biyang; Li, Ke

2016-08-01

Doppler effect is used to measure the relative speed of a moving target with respect to the radar, and is also used to interpret the frequency shift of the backscattering from the ocean wave according to the water-wave phase velocity. The widely known relationship between the Doppler shift and the water-wave phase velocity was deduced from the scattering measurements data collected from actual sea surface, and has not been verified under man-made conditions. Here we show that this ob- served frequency shift of the scattering data from the Bragg and Non-Bragg water wave is not the Doppler shift corresponding to the water-wave phase velocity as commonly believed, but is the water-wave frequency and its integral multiple frequency. The power spectrum of the backscatter from the periodic water wave consists of serials discrete peaks, which is equally spaced by water wave frequency. Only when the water-wave length is the integer multiples of the Bragg wave, and the radar range resolution is infinite, does the frequency shift of the backscattering mathematically equal the Doppler shift according to the water-wave phase velocity.

Continuous particle focusing in a waved microchannel using negative dc dielectrophoresis

KAUST Repository

Li, Ming; Li, Shunbo; Cao, Wenbin; Li, Weihua; Wen, Weijia; Alici, Gursel

2012-01-01

We present a waved microchannel for continuous focusing of microparticles and cells using negative direct current (dc) dielectrophoresis. The waved channel is composed of consecutive s-shaped curved channels in series to generate an electric field

Doppler reflectometry for the investigation of poloidally propagating density perturbations

International Nuclear Information System (INIS)

Hirsch, M.; Baldzuhn, J.; Kurzan, B.; Holzhauer, E.

1999-01-01

A modification of microwave reflectometry is discussed where the direction of observation is tilted with respect to the normal onto the reflecting surface. The experiment is similar to scattering where a finite resolution in k-space exists but keeps the radial localization of reflectometry. The observed poloidal wavenumber is chosen by Bragg's condition via the tilt angle and the resolution in k-space is determined by the antenna pattern. From the Doppler shift of the reflected wave the poloidal propagation velocity of density perturbations is obtained. The diagnostic capabilities of Doppler reflectometry are investigated using full wave code calculations. The method offers the possibility to observe changes in the poloidal propagation velocity of density perturbations and their radial shear with a temporal resolution of about 10μs. (authors)

The role of transvaginal power Doppler ultrasound in the differential diagnosis of benign intrauterine focal lesions.

Science.gov (United States)

Cogendez, Ebru; Eken, Meryem Kurek; Bakal, Nuray; Gun, Ismet; Kaygusuz, Ecmel Isik; Karateke, Ates

2015-10-01

The purpose of this prospective study was to assess the role of power Doppler imaging in the differential diagnosis of benign intrauterine focal lesions such as endometrial polyps and submucous myomas using the characteristics of power Doppler flow mapping. A total of 480 premenopausal patients with abnormal uterine bleeding were evaluated by transvaginal ultrasonography (TVS) searching for intrauterine pathology. Sixty-four patients with a suspicious focal endometrial lesion received saline infusion sonography (SIS) after TVS. Fifty-eight patients with focal endometrial lesions underwent power Doppler ultrasound (PDUS). Three different vascular flow patterns were defined: Single vessel pattern, multiple vessel pattern, and circular flow pattern. Finally, hysteroscopic resection was performed in all cases, and Doppler flow characteristics were then compared with the final histopathological findings. Histopathological results were as follows: endometrial polyp: 40 (69 %), submucous myoma: 18 (31 %). Of the cases with endometrial polyps, 80 % demonstrated a single vessel pattern, 7.5 % a multiple vessel pattern, and 0 % a circular pattern. Vascularization was not observed in 12.5 % of patients with polyps. Of the cases with submucousal myomas, 72.2 % demonstrated a circular flow pattern, 27.8 % a multiple vessel pattern, and none of them showed a single vessel pattern. The sensitivity, specificity, and positive and negative predictive values of the single vessel pattern in diagnosing endometrial polyps were 80, 100, 100, and 69.2 %, respectively; and for the circular pattern in diagnosing submucous myoma, these were 72.2, 100, 100, and 88.9 %, respectively. Power Doppler blood flow mapping is a useful, practical, and noninvasive diagnostic method for the differential diagnosis of benign intrauterine focal lesions. Especially in cases of recurrent abnormal uterine bleeding, recurrent abortion, and infertility, PDUS can be preferred as a first-line diagnostic method.

Usefulness of pulse-wave doppler tissue sampling and dobutamine stress echocardiography for identification of false positive inferior wall defects in SPECT

International Nuclear Information System (INIS)

Altinmakas, S.; Dagdeviren, B.; Turkmen, M.; Gursurer, M.; Say, B.; Tezel, T.; Ersek, B.

2000-01-01

False positive inferior wall perfusion defects restrict the accuracy of SPECT in diagnosis of coronary artery disease (CAD). Pulse-Wave Tissue Doppler (PWTD) has been recently proposed to assess regional wall motion velocities. The objectives of this study were to evaluate the presence of CAD by using PWTD during dobutamine stress echocardiography (DSE) in patients with an inferior perfusion defect detected by SPECT and compare PWTD parameters of normal cases with patients who had inferior perfusion defect and CAD. Sixty-five patients (mean age 58±8 years, 30 men) with a normal LV systolic function at rest according to echocardiographic evaluation with an inferior ischemia determined by SPECT and a control group (CG) of 34 normal cases (mean age 56±7 years, 16 men) were included in this study. All patients underwent a standard DSE (up to 40 μg/kg/min with additional atropine during sub-maximum heart rate responses). Pulse-wave Doppler tissue sampling of inferior wall was performed in the apical 2-chamber view at rest and stress. The coronary angiography was performed within 24 hours. The results were evaluated for the prediction of significant right coronary artery (RCA) and/or left circumflex coronary artery (CX) with narrowing (≥50% diameter stenosis, assessed by quantitative coronary angiography). It was observed that the peak stress mean E/A ratio was lower in patients with CAD when compared to patients without CAD (0.78±0.2 versus 1.29±0.11 p<0.0001). Also the peak stress E/A ratio of normal cases was significantly higher than patients who had CAD (1.19±0.3 versus 0.78±0.2 p<0.0001). When the cut off point for the E/A ratio was determined as 1, the sensitivity and specificity of dobutamine stress PWTD E/A were 89% and 86%, respectively. The peak stress E/A ratio was higher than 1 in all patients with a false positive perfusion defect. Systolic S velocity increase during DSE was significantly lower in patients with CAD (54%±17 versus 99%±24 p=0

[Ultrasound and color Doppler applications in nephrology. The normal kidney: anatomy, vessels and congenital anomalies].

Science.gov (United States)

Meola, Mario; Petrucci, Ilaria; Giovannini, Lisa; Samoni, Sara; Dellafiore, Carolina

2012-01-01

Gray-scale ultrasound is the diagnostic technique of choice in patients with suspected or known renal disease. Knowledge of the normal and abnormal sonographic morphology of the kidney and urinary tract is essential for a successful diagnosis. Conventional sonography must always be complemented by Doppler sampling of the principal arterial and venous vessels. B-mode scanning is performed with the patient in supine, prone or side position. The kidney can be imaged by the anterior, lateral or posterior approach using coronal, transverse and oblique scanning planes. Morphological parameters that must be evaluated are the coronal diameter, the parenchymal thickness and echogenicity, the structure and state of the urinary tract, and the presence of congenital anomalies that may mimic a pseudomass. The main renal artery and the hilar-intraparenchymal branches of the arterial and venous vessels should be accurately evaluated using color Doppler. Measurement of intraparenchymal resistance indices (IP, IR) provides an indirect and quantitative parameter of the stiffness and eutrophic or dystrophic remodeling of the intrarenal microvasculature. These parameters differ depending on age, diabetic and hypertensive disease, chronic renal glomerular disease, and interstitial, vascular and obstructive nephropathy.

A micro-Doppler sonar for acoustic surveillance in sensor networks

Science.gov (United States)

Zhang, Zhaonian

Wireless sensor networks have been employed in a wide variety of applications, despite the limited energy and communication resources at each sensor node. Low power custom VLSI chips implementing passive acoustic sensing algorithms have been successfully integrated into an acoustic surveillance unit and demonstrated for detection and location of sound sources. In this dissertation, I explore active and passive acoustic sensing techniques, signal processing and classification algorithms for detection and classification in a multinodal sensor network environment. I will present the design and characterization of a continuous-wave micro-Doppler sonar to image objects with articulated moving components. As an example application for this system, we use it to image gaits of humans and four-legged animals. I will present the micro-Doppler gait signatures of a walking person, a dog and a horse. I will discuss the resolution and range of this micro-Doppler sonar and use experimental results to support the theoretical analyses. In order to reduce the data rate and make the system amenable to wireless sensor networks, I will present a second micro-Doppler sonar that uses bandpass sampling for data acquisition. Speech recognition algorithms are explored for biometric identifications from one's gait, and I will present and compare the classification performance of the two systems. The acoustic micro-Doppler sonar design and biometric identification results are the first in the field as the previous work used either video camera or microwave technology. I will also review bearing estimation algorithms and present results of applying these algorithms for bearing estimation and tracking of moving vehicles. Another major source of the power consumption at each sensor node is the wireless interface. To address the need of low power communications in a wireless sensor network, I will also discuss the design and implementation of ultra wideband transmitters in a three dimensional

The cardiac sonography workforce in New Zealand

Science.gov (United States)

White, Steve; Poppe, Katrina; Whalley, Gillian

2015-01-01

Abstract Introduction: The aim of this paper is to investigate the cardiac sonography workforce characteristics and registration requirements in New Zealand (NZ), with a comparison to similar workforces internationally. Methods: The Survey of Clinical Echocardiography in New Zealand 2 (SCANZ2) audit was performed in December 2010. All of NZ's public‐funded District Health Board (DHB) centers providing echocardiography services responded to questions relating to staff, equipment, procedure types and patient statistics. The Medical Radiation Technologists Board (MRTB), Clinical Physiologists Registration Board (CPRB) and Australian Sonographers Association Registry (ASAR) websites were reviewed in March 2012 for registered sonographers with a cardiac scope of practice. The cardiac sonography workforces in Australia, the UK, the USA and Canada were investigated for comparison. Results: There are 84 cardiac sonographers (60.3 full‐time equivalent) working in DHBs: 71% from a cardiac technical background; 40% have post‐graduate qualifications; a further 17% are undertaking post‐graduate qualifications; and 59 cardiac sonographers have registration with professional bodies in NZ and/or Australia. Cardiac sonographers in NZ do not undergo compulsory registration, but other sonographers in NZ have compulsory registration with the MRTB. Sonographers are predominantly not licensed internationally. Discussion: Disparity exists between registration of cardiac and non‐cardiac sonographers in NZ. Many cardiac sonographers have voluntary registration but few are registered with the MRTB. Reasons for this include professional alignment, educational qualifications and representation. International trends show increased pressure from governments and professional bodies to regulate sonographers. Conclusion: This study provides a snapshot of the cardiac sonography workforce in NZ for the first time. PMID:28191178

Continuous-wave terahertz light from optical parametric oscillators

Energy Technology Data Exchange (ETDEWEB)

Sowade, Rosita

2010-12-15

Continuous-wave (cw) optical parametric oscillators (OPOs) are working horses for spectroscopy in the near and mid infrared. However, in the terahertz frequency range (0.1 to 10 THz), the pump threshold is more than 100 W due to the high absorption in nonlinear crystals and thus exceeds the power of standard cw single-frequency pump sources. In this thesis the first cw OPO capable of generating terahertz radiation is demonstrated. To overcome the high threshold, the signal wave of a primary infrared process is resonantly enhanced to serve as the pump wave for a cascaded parametric process with one wave being at the terahertz frequency level. A terahertz output power of more than two microwatts is measured and tuning is achieved from 1.3 to 1.7 THz. This terahertz source emits a narrow-band, diffraction-limited beam which remains mode-hop free over more than one hour. Such a device inhibits high potential for applications in areas like astronomy, telecommunications or high-resolution spectroscopy. (orig.)

Continuous-wave terahertz light from optical parametric oscillators

International Nuclear Information System (INIS)

Sowade, Rosita

2010-12-01

Continuous-wave (cw) optical parametric oscillators (OPOs) are working horses for spectroscopy in the near and mid infrared. However, in the terahertz frequency range (0.1 to 10 THz), the pump threshold is more than 100 W due to the high absorption in nonlinear crystals and thus exceeds the power of standard cw single-frequency pump sources. In this thesis the first cw OPO capable of generating terahertz radiation is demonstrated. To overcome the high threshold, the signal wave of a primary infrared process is resonantly enhanced to serve as the pump wave for a cascaded parametric process with one wave being at the terahertz frequency level. A terahertz output power of more than two microwatts is measured and tuning is achieved from 1.3 to 1.7 THz. This terahertz source emits a narrow-band, diffraction-limited beam which remains mode-hop free over more than one hour. Such a device inhibits high potential for applications in areas like astronomy, telecommunications or high-resolution spectroscopy. (orig.)

Direct measurement of Lorentz transformation with Doppler effects

Science.gov (United States)

Chen, Shao-Guang

For space science and astronomy the fundamentality of one-way velocity of light (OWVL) is selfevident. The measurement of OWVL (distance/interval) and the clock synchronization with light-signal transfer make a logical circulation. This means that OWVL could not be directly measured but only come indirectly from astronomical method (Romer's Io eclipse and Bradley's sidereal aberration), furthermore, the light-year by definitional OWVL and the trigonometry distance with AU are also un-measurable. For to solve this problem two methods of clock synchronization were proposed: The direct method is that at one end of dual-speed transmissionline with single clock measure the arriving-time difference of longitudinal wave and transverse wave or ordinary light and extraordinary light, again to calculate the collective sending-time of two wave with Yang's /shear elastic-modulus ratio (E/k) or extraordinary/ordinary light refractive-index ratio (ne/no), which work as one earthquake-station with single clock measures first-shake time and the distance to epicenter; The indirect method is that the one-way wavelength l is measured by dual-counters Ca and Cb and computer's real-time operation of reading difference (Nb - Na) of two counters, the frequency f is also simultaneously measured, then l f is just OWVL. Therefore, with classical Newtonian mechanics and ether wave optics, OWVL can be measured in the Galileo coordinate system with an isotropic length unit (1889 international meter definition). Without any hypotheses special relativity can entirely establish on the metrical results. When a certain wavelength l is defined as length unit, foregoing measurement of one-way wavelength l will become as the measurement of rod's length. Let a rigidity-rod connecting Ca and Cb moves relative to lamp-house with velocity v, rod's length L = (Nb - Na) l will change follow v by known Doppler effect, i.e., L(q) =L0 (1+ (v/c) cos q), where L0 is the proper length when v= 0, v• r = v cos q

Diagnostic value of Doppler echocardiography for identifying hemodynamic significant pulmonary valve regurgitation in tetralogy of Fallot: comparison with cardiac MRI.

Science.gov (United States)

Beurskens, Niek E G; Gorter, Thomas M; Pieper, Petronella G; Hoendermis, Elke S; Bartelds, Beatrijs; Ebels, Tjark; Berger, Rolf M F; Willems, Tineke P; van Melle, Joost P

2017-11-01

Quantification of pulmonary regurgitation (PR) is essential in the management of patients with repaired tetralogy of Fallot (TOF). We sought to evaluate the accuracy of first-line Doppler echocardiography in comparison with cardiac magnetic resonance imaging (MRI) to identify hemodynamic significant PR. Paired cardiac MRI and echocardiographic studies (n = 97) in patients with repaired TOF were retrospectively analyzed. Pressure half time (PHT) and pulmonary regurgitation index (PRi) were measured using continuous wave Doppler. The ratio of the color flow Doppler regurgitation jet width to pulmonary valve (PV) annulus (jet/annulus ratio) and diastolic to systolic time velocity integral (DSTVI; pulsed wave Doppler) were assessed. Accuracy of echocardiographic measurements was tested to identify significant PR as determined by phase-contrast MRI (PR fraction [PRF] ≥ 20%). Mean PRF was 29.4 ± 15.7%. PHT < 100 ms had a sensitivity of 93%, specificity 75%, positive predictive value (PPV) 92% and negative predictive value (NPV) 78% for identifying significant PR (C-statistic 0.82). PRi < 0.77 had sensitivity and specificity of 66% and 54%, respectively (C-statistic 0.63). Jet/annulus ratio ≥1/3 had sensitivity 96%, specificity 75%, PPV 92% and NPV 82% (C-statistic 0.87). DSTVI had sensitivity 84%, specificity 33%, PPV 84% and NPV 40%, (C-statistic 0.56). Combined jet/annulus ratio ≥1/3 and PHT < 100 ms was highly accurate in identifying PRF ≥ 20%, with sensitivity 97% and specificity 100%. PHT and jet/annulus ratio on Doppler echocardiography, especially when combined, are highly accurate in identifying significant PR and therefore seem useful in the follow-up of patients with repaired TOF.

Continuous particle focusing in a waved microchannel using negative dc dielectrophoresis

KAUST Repository

Li, Ming

2012-07-26

We present a waved microchannel for continuous focusing of microparticles and cells using negative direct current (dc) dielectrophoresis. The waved channel is composed of consecutive s-shaped curved channels in series to generate an electric field gradient required for the dielectrophoretic effect. When particles move electrokinetically through the channel, the experienced negative dielectrophoretic forces alternate directions within two adjacent semicircular microchannels, leading to a focused continuous-flow stream along the channel centerline. Both the experimentally observed and numerically simulated results of the focusing performance are reported, which coincide acceptably in proportion to the specified dimensions (i.e. inlet and outlet of the waved channel). How the applied electric field, particle size and medium concentration affect the performance was studied by focusing polystyrene microparticles of varying sizes. As an application in the field of biology, the focusing of yeast cells in the waved mcirochannel was tested. This waved microchannel shows a great potential for microflow cytometry applications and is expected to be widely used before different processing steps in lab-on-A-chip devices with integrated functions. © 2012 IOP Publishing Ltd.

Assessment of cutaneous radiation fibrosis by 20 MHz-sonography

International Nuclear Information System (INIS)

Gottloeber, P.; Braun-Falco, B.; Plewig, G.; Kerscher, M.; Peter, R.U.; Nadeshina, N.

1996-01-01

Radiation fibrosis is the cardinal symptom of the chronicle stage of the cutaneous radiation syndrome. The degree of cutaneous fibrosis can clinically be estimated by palpation. High-frequency 20 MHz-sonography is an established, noninvasive procedure, which renders an exact determination of skin thickness and additionally densitometry is possible. We investigated 15 survivors of the Chernobyl accident in 1986, who developed symptoms of the chronic stage of the cutaneous radiation syndrome. We determined skin thickness and echogenicity of skin areas clinically suggestive of radiation fibrosis before, during and after treatment. 20 MHz-sonography showed a distinct enlargement of the echorich corium and a reduction of the subcutaneous fatty tissue in comparison with the unaffected, contralateral skin, here demonstrating typical features of radiation fibrosis, namely dermal fibrosis and reactive pseudoatrophy and fatty tissue. The histology presented an increase and swelling of the collagen fibers and atypical fibroblastic cells. The patients received treatment with low-dose interferon y (Polyfcron R , 3 x 50μg s.C., three times per week) up to 30 months. A marked reduction of skin thickness and echogenicity reaching nearly normal values could be observed. We conclude that 20 MHz-sonography is an easy to apply, noninvasive, well established procedure to quantify cutaneous radiation fibrosis and to assess therapeutic outcome

Diagnostic imaging strategy for MDCT- or MRI-detected breast lesions: use of targeted sonography

International Nuclear Information System (INIS)

Nakano, Satoko; Ohtsuka, Masahiko; Mibu, Akemi; Karikomi, Masato; Sakata, Hitomi; Yamamoto, Masahiro

2012-01-01

Leading-edge technology such as magnetic resonance imaging (MRI) or computed tomography (CT) often reveals mammographically and ultrasonographically occult lesions. MRI is a well-documented, effective tool to evaluate these lesions; however, the detection rate of targeted sonography varies for MRI detected lesions, and its significance is not well established in diagnostic strategy of MRI detected lesions. We assessed the utility of targeted sonography for multidetector-row CT (MDCT)- or MRI-detected lesions in practice. We retrospectively reviewed 695 patients with newly diagnosed breast cancer who were candidates for breast conserving surgery and underwent MDCT or MRI in our hospital between January 2004 and March 2011. Targeted sonography was performed in all MDCT- or MRI-detected lesions followed by imaging-guided biopsy. Patient background, histopathology features and the sizes of the lesions were compared among benign, malignant and follow-up groups. Of the 695 patients, 61 lesions in 56 patients were detected by MDCT or MRI. The MDCT- or MRI-detected lesions were identified by targeted sonography in 58 out of 61 lesions (95.1%). Patients with pathological diagnoses were significantly older and more likely to be postmenopausal than the follow-up patients. Pathological diagnosis proved to be benign in 20 cases and malignant in 25. The remaining 16 lesions have been followed up. Lesion size and shape were not significantly different among the benign, malignant and follow-up groups. Approximately 95% of MDCT- or MRI-detected lesions were identified by targeted sonography, and nearly half of these lesions were pathologically proven malignancies in this study. Targeted sonography is a useful modality for MDCT- or MRI-detected breast lesions

Measurement of fast-changing low velocities by photonic Doppler velocimetry

Energy Technology Data Exchange (ETDEWEB)

Song Hongwei; Wu Xianqian; Huang Chenguang; Wei Yangpeng; Wang Xi [Key Laboratory for Hydrodynamics and Ocean Engineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China)

2012-07-15

Despite the increasing popularity of photonic Doppler velocimetry (PDV) in shock wave experiments, its capability of capturing low particle velocities while changing rapidly is still questionable. The paper discusses the performance of short time Fourier transform (STFT) and continuous wavelet transform (CWT) in processing fringe signals of fast-changing low velocities measured by PDV. Two typical experiments are carried out to evaluate the performance. In the laser shock peening test, the CWT gives a better interpretation to the free surface velocity history, where the elastic precursor, main plastic wave, and elastic release wave can be clearly identified. The velocities of stress waves, Hugoniot elastic limit, and the amplitude of shock pressure induced by laser can be obtained from the measurement. In the Kolsky-bar based tests, both methods show validity of processing the longitudinal velocity signal of incident bar, whereas CWT improperly interprets the radial velocity of the shocked sample at the beginning period, indicating the sensitiveness of the CWT to the background noise. STFT is relatively robust in extracting waveforms of low signal-to-noise ratio. Data processing method greatly affects the temporal resolution and velocity resolution of a given fringe signal, usually CWT demonstrates a better local temporal resolution and velocity resolution, due to its adaptability to the local frequency, also due to the finer time-frequency product according to the uncertainty principle.

Sub-Doppler cooling in reduced-period optical lattice geometries

International Nuclear Information System (INIS)

Berman, P.R.; Raithel, G.; Zhang, R.; Malinovsky, V.S.

2005-01-01

It is shown that sub-Doppler cooling occurs in an atom-field geometry that can lead to reduced-period optical lattices. Four optical fields are combined to produce a 'standing wave' Raman field that drives transitions between two ground state sublevels. In contrast to conventional Sisyphus cooling, sub-Doppler cooling to zero velocity occurs when all fields are polarized in the same direction. Solutions are obtained using both semiclassical and quantum Monte Carlo methods in the case of exact two-photon resonance. The connection of the results with conventional Sisyphus cooling is established using a dressed state basis

Acceleration rate of mitral inflow E wave: a novel transmitral doppler index for assessing diastolic function.

Science.gov (United States)

Badkoubeh, Roya Sattarzadeh; Tavoosi, Anahita; Jabbari, Mostafa; Parsa, Amir Farhang Zand; Geraeli, Babak; Saadat, Mohammad; Larti, Farnoosh; Meysamie, Ali Pasha; Salehi, Mehrdad

2016-06-10

We performed comprehensive transmitral and pulmonary venous Doppler echocardiographic studies to devise a novel index of diastolic function. This is the first study to assess the utility of the acceleration rate (AR) of the E wave of mitral inflow as a primary diagnostic modality for assessing diastolic function. Study group consisted of 84 patients (53 + 11 years) with left ventricle (LV) diastolic dysfunction and 34 healthy people (35 ± 9 years) as control group, who were referred for clinically indicated two-dimensional transthoracic echocardiogram (TTE) during 2012 and 2013 to Imam Hospital. Normal controls were defined as patients without clinical evidence of cardiac disease and had normal TTE. LV diastolic function was determined according to standardized protocol of American Society of Echocardiography (ASE). As our new parameter, AR of E wave of mitral inflow was also measured in all patients. It was represented by the slope of the line between onset of E wave and peak of it. Correlation between AR of E wave and LV diastolic function grade was measured using the Spearman correlation coefficient. Receiver operating characteristic (ROC) curve was used to determine the sensitivity and specificity of AR of E wave in diagnosing LV diastolic dysfunction in randomly selected two-thirds of population then its derived cutoff was evaluated in rest of the population. The institutional review board of the hospital approved the study protocol. All participants gave written informed consent. This investigation was in accordance with the Declaration of Helsinki. The mean value of AR was 1010 ± 420 cm/s(2) in patients whereas the mean value for the normal controls was 701 ± 210 cm/s(2). There was a strong and graded relation between AR of E wave of mitral inflow and LV diastolic function grade (Spearman P ≤0.0001, rs =0.69). ROC curve analysis revealed that AR of E wave of mitral inflow =750 cm/s(2) predicted moderate or severe LV diastolic

Wave function continuity and the diagonal Born-Oppenheimer correction at conical intersections.

Science.gov (United States)

Meek, Garrett A; Levine, Benjamin G

2016-05-14

We demonstrate that though exact in principle, the expansion of the total molecular wave function as a sum over adiabatic Born-Oppenheimer (BO) vibronic states makes inclusion of the second-derivative nonadiabatic energy term near conical intersections practically problematic. In order to construct a well-behaved molecular wave function that has density at a conical intersection, the individual BO vibronic states in the summation must be discontinuous. When the second-derivative nonadiabatic terms are added to the Hamiltonian, singularities in the diagonal BO corrections (DBOCs) of the individual BO states arise from these discontinuities. In contrast to the well-known singularities in the first-derivative couplings at conical intersections, these singularities are non-integrable, resulting in undefined DBOC matrix elements. Though these singularities suggest that the exact molecular wave function may not have density at the conical intersection point, there is no physical basis for this constraint. Instead, the singularities are artifacts of the chosen basis of discontinuous functions. We also demonstrate that continuity of the total molecular wave function does not require continuity of the individual adiabatic nuclear wave functions. We classify nonadiabatic molecular dynamics methods according to the constraints placed on wave function continuity and analyze their formal properties. Based on our analysis, it is recommended that the DBOC be neglected when employing mixed quantum-classical methods and certain approximate quantum dynamical methods in the adiabatic representation.

Specific preoperative diagnosis of choledochal cysts by combined sonography and hepatobiliary scintigraphy

International Nuclear Information System (INIS)

Papanicolaou, N.; Abramson, S.J.; Teele, R.L.; Treves, S.

1985-01-01

The combined use of sonography and hepatobiliary scintigraphy correctly identified a choledochal cyst preoperatively in seven consecutive infants and children. The high resolution anatomic images provided by sonography coupled with physiologic data on filing of the cyst, biliary patency and liver function derived from radionuclide scanning offer valuable information in the diagnosis and planning of corrective surgery of the cyst and coexisting hepatobiliary anomalies. Invasive diagnostic procedures should be reserved for occasional problematic cases [fr

Christian Andreas Doppler--the man and his legacy.

Science.gov (United States)

Coman, I M

2005-01-01

Reminding the life and legacy of the Austrian Scientist who discovered the famous 'Doppler Effect'. C.A. Doppler was born the 29th of November 1803 in Salzburg. After studies in Linz and Vienna, he graduated in mathematics, became assistant at the University and later worked as a professor in Prague. Back to Vienna, he was appointed as professor at the Polytechnic School and --in 1850--as first director of the new Institute of Physics. C.A. Doppler did publish on magnetism, electricity, optics, and astronomy. He remains in the history of science due to the discovery presented (May 25, 1842) at the Royal Bohemian Society of Science entitled "On the colored light of the double stars and certain other stars of the heavens"; the paper described (applied to light) the shift of frequency which bears nowadays his name. The theory was later experimentally proven and--extended for any electromagnetic and acoustic waves--got myriads if applications in astronomy, physics, aviation, meteorology, and health science. Satomura in Japan (1955) published it's first ultrasound vascular application--with successive achievements in the next decades. Doppler ultrasonagraphy became the main noninvasive instrument for functional assesment of heart and vessels.

Doppler sonographic evaluation of ophthalmic arterial flow pattern in hypertensive patients

International Nuclear Information System (INIS)

Ryu, Dae Sik; Kim, Young Goo

1994-01-01

To compare the Doppler velocity waveform pattern of ophthalmic artery of hypertensive patients with that of normotensive subjects. Doppler velocity waveform was obtained from ophthalmic artery in 45 hypertensive patients and 60 normotensive subjects. Both hypertensives and normotensive subjects were classified according to age into those younger than and those older than 45 years. Doppler indices(pulsatility index(PI), resistance index(RI), the first systolic peak/the second systolic peak(S1/S2), the first systolic peak/diastolic peak(S1/D)) measured in hypertensive patients were compared with normotensive subjects. Among the various doppler indices, only S1/S2 showed significant difference(P < 0.05) between the hypertensive patients and normotensive subjects younger than 45 years. Doppler velocity waveform of hypertensive patients older than 45 years showed no significant difference from that of normotensive subjects with corresponding age. Doppler velocity waveform of ophthalmic artery in hypertensive patients younger than 45 years shows pattern with S2 higher than that of normotensive subjects. High S2 component(reflective-wave) may represent increased vascular impedance due to vasococonstriction of retinal arterioles in hypertensive patients

Time-Frequency-Wavenumber Analysis of Surface Waves Using the Continuous Wavelet Transform

Science.gov (United States)

Poggi, V.; Fäh, D.; Giardini, D.

2013-03-01

A modified approach to surface wave dispersion analysis using active sources is proposed. The method is based on continuous recordings, and uses the continuous wavelet transform to analyze the phase velocity dispersion of surface waves. This gives the possibility to accurately localize the phase information in time, and to isolate the most significant contribution of the surface waves. To extract the dispersion information, then, a hybrid technique is applied to the narrowband filtered seismic recordings. The technique combines the flexibility of the slant stack method in identifying waves that propagate in space and time, with the resolution of f- k approaches. This is particularly beneficial for higher mode identification in cases of high noise levels. To process the continuous wavelet transform, a new mother wavelet is presented and compared to the classical and widely used Morlet type. The proposed wavelet is obtained from a raised-cosine envelope function (Hanning type). The proposed approach is particularly suitable when using continuous recordings (e.g., from seismological-like equipment) since it does not require any hardware-based source triggering. This can be subsequently done with the proposed method. Estimation of the surface wave phase delay is performed in the frequency domain by means of a covariance matrix averaging procedure over successive wave field excitations. Thus, no record stacking is necessary in the time domain and a large number of consecutive shots can be used. This leads to a certain simplification of the field procedures. To demonstrate the effectiveness of the method, we tested it on synthetics as well on real field data. For the real case we also combine dispersion curves from ambient vibrations and active measurements.

Gravitational wave searches using the DSN (Deep Space Network)

International Nuclear Information System (INIS)

Nelson, S.J.; Armstrong, J.W.

1988-01-01

The Deep Space Network Doppler spacecraft link is currently the only method available for broadband gravitational wave searches in the 0.01 to 0.001 Hz frequency range. The DSN's role in the worldwide search for gravitational waves is described by first summarizing from the literature current theoretical estimates of gravitational wave strengths and time scales from various astrophysical sources. Current and future detection schemes for ground based and space based detectors are then discussed. Past, present, and future planned or proposed gravitational wave experiments using DSN Doppler tracking are described. Lastly, some major technical challenges to improve gravitational wave sensitivities using the DSN are discussed

Quantitative Assessment of Synovial Vascularity Using Contrast-Enhanced Power Doppler Ultrasonography: Correlation with Histologic Findings and MR Imaging Findings in Arthritic Rabbit Knee Model

International Nuclear Information System (INIS)

Lee, Sang Hoon; Shin, Myung Jin; Kim, Seong Moon; Kim, Namkug; Suh, Sang Hyun; Suh, Jin Suck

2008-01-01

To validate contrast-enhanced power Doppler ultrasonography (PD US) for the evaluation of synovial vascularity in an arthritic rabbit knee model in correlation with MR and histological findings. Power Doppler ultrasonography was performed for carrageenin-induced arthritic left knee and control right knee of 13 rabbits, first without and then with sonic contrast agent enhancement (Levovist, Schering, Berlin Germany), followed by gadolinium-enhanced MR imaging. Synovial vascularity was quantitatively assessed by calculating the color pixel area in power Doppler sonography using a computer-aided image analysis program and by grading the enhancement on MR images: grade 1, enhancement of knee joint is less than one-third of the area; grade 2, one-third to two-thirds enhancement; and grade 3, more than two-thirds enhancement. Microvessel density (MVD) was measured on slides stained immunohistochemically for CD31 antigen for histological assessment. The mean area of color pixels in PD US changed from 4.37 to 16.42 mm 2 in the arthritic knee after enhancement (p 2 in the control knee (p 0.05). Sonic contrast-enhanced PD US improves the visualization of synovial vascularity and allows quantitative measurement in experimentally induced rabbit arthritic knees

Chest sonography. 2. ed.

Energy Technology Data Exchange (ETDEWEB)

Mathis, Gebhard (ed.)

2008-07-01

Chest sonography is an established procedure in the stepwise imaging diagnosis of pulmonary and pleural disease. It is the method of choice to distinguish between solid and liquid lesions and allows the investigator to make an unequivocal diagnosis without exposing the patient to costly and stressful procedures. This book presents the state of the art in chest investigation by means of ultrasonography. A number of excellent illustrations and the compact text provide concise and easy-to-assimilate information about the diagnostic procedure. Basic elements such as indications, investigation techniques and image artifacts are detailed in separate chapters. (orig.)

Chest sonography. 2. ed.

International Nuclear Information System (INIS)

Mathis, Gebhard

2008-01-01

Chest sonography is an established procedure in the stepwise imaging diagnosis of pulmonary and pleural disease. It is the method of choice to distinguish between solid and liquid lesions and allows the investigator to make an unequivocal diagnosis without exposing the patient to costly and stressful procedures. This book presents the state of the art in chest investigation by means of ultrasonography. A number of excellent illustrations and the compact text provide concise and easy-to-assimilate information about the diagnostic procedure. Basic elements such as indications, investigation techniques and image artifacts are detailed in separate chapters. (orig.)

The forgotten organ: Contrast enhanced sonography of the spleen

International Nuclear Information System (INIS)

Goerg, Christian

2007-01-01

Objective: Ultrasound contrast agents in conjunction with contrast specific imaging techniques, are increasingly accepted in clinical use for diagnostic imaging in several organs. Contrast enhanced sonography (CES) of second-generation contrast media have shown a spleen-specific uptake of the microbubble contrast agent. The aim of this review is to illustrate indications for the use of CES in patients with suspected (peri-)splenic pathology. Methods: This review based on the experience of transcutaneous CES in 200 patients with (peri-)splenic pathology diagnosed by B-mode sonography at an internal medicine center. CES studies were performed with a contrast-devoted unit (Acuson, Sequoia, Siemens medical solution) that had contrast-specific, continuous-mode software. A low mechanical index was used. A sulfur hexafluoride-based microbubble contrast medium (Sonovue, Bracco SpA, Milan, Italy) was injected. Results: On our experience, there are several clinical conditions which may show an diagnostic advantage of CES in comparison to B-mode US. CES should be performed to investigate: (1) the perisplenic tumor to diagnose or exclude accessory spleen, (2) the small-sized spleen to diagnose functional asplenia/hyposplenia, (3) the inhomogenous spleen of unknown cause to diagnose focal lesions within the spleen, (4) the incidentally found hypoechoic splenic tumor to diagnose high vascular splenic hemangioma, (5) focal lesions suspect for splenic abscess, hematoma, infarction to confirme diagnosis, and (6) patients with abdominal trauma to diagnose or exclude splenic injuriy. Conclusion: CES is of diagnostic value in several clinical circumstances to diagnose accessory spleen, functional asplenia, small-sized splenic involvement, high vascular splenic hemangioma, and vascular splenic pathology like splenic infarction, splenic abscess, and splenic laceration

The forgotten organ: Contrast enhanced sonography of the spleen

Energy Technology Data Exchange (ETDEWEB)

Goerg, Christian [Medizinische Universitaetsklinik, Baldingerstrasse, 35043 Marburg/Lahn (Germany)], E-mail: goergc@med.uni-marburg.de

2007-11-15

Objective: Ultrasound contrast agents in conjunction with contrast specific imaging techniques, are increasingly accepted in clinical use for diagnostic imaging in several organs. Contrast enhanced sonography (CES) of second-generation contrast media have shown a spleen-specific uptake of the microbubble contrast agent. The aim of this review is to illustrate indications for the use of CES in patients with suspected (peri-)splenic pathology. Methods: This review based on the experience of transcutaneous CES in 200 patients with (peri-)splenic pathology diagnosed by B-mode sonography at an internal medicine center. CES studies were performed with a contrast-devoted unit (Acuson, Sequoia, Siemens medical solution) that had contrast-specific, continuous-mode software. A low mechanical index was used. A sulfur hexafluoride-based microbubble contrast medium (Sonovue, Bracco SpA, Milan, Italy) was injected. Results: On our experience, there are several clinical conditions which may show an diagnostic advantage of CES in comparison to B-mode US. CES should be performed to investigate: (1) the perisplenic tumor to diagnose or exclude accessory spleen, (2) the small-sized spleen to diagnose functional asplenia/hyposplenia, (3) the inhomogenous spleen of unknown cause to diagnose focal lesions within the spleen, (4) the incidentally found hypoechoic splenic tumor to diagnose high vascular splenic hemangioma, (5) focal lesions suspect for splenic abscess, hematoma, infarction to confirme diagnosis, and (6) patients with abdominal trauma to diagnose or exclude splenic injuriy. Conclusion: CES is of diagnostic value in several clinical circumstances to diagnose accessory spleen, functional asplenia, small-sized splenic involvement, high vascular splenic hemangioma, and vascular splenic pathology like splenic infarction, splenic abscess, and splenic laceration.

Bi-directional ultrasonic wave coupling to FBGs in continuously bonded optical fiber sensing.

Science.gov (United States)

Wee, Junghyun; Hackney, Drew; Bradford, Philip; Peters, Kara

2017-09-01

Fiber Bragg grating (FBG) sensors are typically spot-bonded onto the surface of a structure to detect ultrasonic waves in laboratory demonstrations. However, to protect the rest of the optical fiber from any environmental damage during real applications, bonding the entire length of fiber, called continuous bonding, is commonly done. In this paper, we investigate the impact of continuously bonding FBGs on the measured Lamb wave signal. In theory, the ultrasonic wave signal can bi-directionally transfer between the optical fiber and the plate at any adhered location, which could potentially produce output signal distortion for the continuous bonding case. Therefore, an experiment is performed to investigate the plate-to-fiber and fiber-to-plate signal transfer, from which the signal coupling coefficient of each case is theoretically estimated based on the experimental data. We demonstrate that the two coupling coefficients are comparable, with the plate-to-fiber case approximately 19% larger than the fiber-to-plate case. Finally, the signal waveform and arrival time of the output FBG responses are compared between the continuous and spot bonding cases. The results indicate that the resulting Lamb wave signal output is only that directly detected at the FBG location; however, a slight difference in signal waveform is observed between the two bonding configurations. This paper demonstrates the practicality of using continuously bonded FBGs for ultrasonic wave detection in structural health monitoring (SHM) applications.

Continuous wave room temperature external ring cavity quantum cascade laser

Energy Technology Data Exchange (ETDEWEB)

Revin, D. G., E-mail: d.revin@sheffield.ac.uk; Hemingway, M.; Vaitiekus, D.; Cockburn, J. W. [Physics and Astronomy Department, The University of Sheffield, S3 7RH Sheffield (United Kingdom); Hempler, N.; Maker, G. T.; Malcolm, G. P. A. [M Squared Lasers Ltd., G20 0SP Glasgow (United Kingdom)

2015-06-29

An external ring cavity quantum cascade laser operating at ∼5.2 μm wavelength in a continuous-wave regime at the temperature of 15 °C is demonstrated. Out-coupled continuous-wave optical powers of up to 23 mW are observed for light of one propagation direction with an estimated total intra-cavity optical power flux in excess of 340 mW. The uni-directional regime characterized by the intensity ratio of more than 60 for the light propagating in the opposite directions was achieved. A single emission peak wavelength tuning range of 90 cm{sup −1} is realized by the incorporation of a diffraction grating into the cavity.

Continuous wave room temperature external ring cavity quantum cascade laser

International Nuclear Information System (INIS)

Revin, D. G.; Hemingway, M.; Vaitiekus, D.; Cockburn, J. W.; Hempler, N.; Maker, G. T.; Malcolm, G. P. A.

2015-01-01

An external ring cavity quantum cascade laser operating at ∼5.2 μm wavelength in a continuous-wave regime at the temperature of 15 °C is demonstrated. Out-coupled continuous-wave optical powers of up to 23 mW are observed for light of one propagation direction with an estimated total intra-cavity optical power flux in excess of 340 mW. The uni-directional regime characterized by the intensity ratio of more than 60 for the light propagating in the opposite directions was achieved. A single emission peak wavelength tuning range of 90 cm −1 is realized by the incorporation of a diffraction grating into the cavity

Muscle lesion comparing of imaging procedures (sonography and MRT) -experimental and clinical study

International Nuclear Information System (INIS)

Mellerowicz, H.; Lubasch, A.; Dulce, M.; Wagner, S.; Paul, B.

1993-01-01

Muscle injuries in sports are more common now. Diagnosis and follow up of muscle injuries is nowadays achieved by sonography and MRT. In order to assess the two imagine procedures, a direct test for comparison of sonography and MRT was performed in an experimental study: A standardised disconnection of m. triceps surae in rats was either sutured and glued or not treated. Clinical studies were performed in 26 patients suffering from muscle trauma. Sonography was proved to be a reliable procedure especially in follow up control until full weight bearing and should be used first. Negative or doubtfull findings require further investigation by MRT. Especially contrast medium (Gd-DTPA) assisted examinations enables a long term follow up and may even show small (muscle strain) and deep lying injuries. (orig.) [de

Continuous-wave lasing in an organic-inorganic lead halide perovskite semiconductor

Science.gov (United States)

Jia, Yufei; Kerner, Ross A.; Grede, Alex J.; Rand, Barry P.; Giebink, Noel C.

2017-12-01

Hybrid organic-inorganic perovskites have emerged as promising gain media for tunable, solution-processed semiconductor lasers. However, continuous-wave operation has not been achieved so far1-3. Here, we demonstrate that optically pumped continuous-wave lasing can be sustained above threshold excitation intensities of 17 kW cm-2 for over an hour in methylammonium lead iodide (MAPbI3) distributed feedback lasers that are maintained below the MAPbI3 tetragonal-to-orthorhombic phase transition temperature of T ≈ 160 K. In contrast with the lasing death phenomenon that occurs for pure tetragonal-phase MAPbI3 at T > 160 K (ref. 4), we find that continuous-wave gain becomes possible at T ≈ 100 K from tetragonal-phase inclusions that are photogenerated by the pump within the normally existing, larger-bandgap orthorhombic host matrix. In this mixed-phase system, the tetragonal inclusions function as carrier recombination sinks that reduce the transparency threshold, in loose analogy to inorganic semiconductor quantum wells, and may serve as a model for engineering improved perovskite gain media.

Correlation between sonography and antibody activity in patients with Hashimoto thyroiditis.

Science.gov (United States)

Willms, Arnulf; Bieler, Dan; Wieler, Helmut; Willms, Diana; Kaiser, Klaus P; Schwab, Robert

2013-11-01

Patients with Hashimoto thyroiditis show structural changes of the thyroid that can be identified by a variety of sonographic criteria. We conducted this study to investigate whether there is a correlation between sonography and antibody activity and to assess the role of sonography in the diagnosis and follow-up of Hashimoto thyroiditis. In addition, we present a new classification system (termed the VESINC system [volume, echogenicity, sonographic texture, pseudonodular hypoechoic infiltration, nodules, and cysts]), which helps improve the clarity of sonographic findings. The study included 223 consecutive patients with previously diagnosed Hashimoto autoimmune thyroiditis who attended the thyroid clinic of the German Armed Forces Central Hospital in Koblenz for follow-up examinations between 2006 and 2008. Laboratory tests were performed to measure the levels of free triiodothyronine, free thyroxine, thyrotropin, anti-thyroglobulin antibodies (TgAbs), and antithyroid peroxidase antibodies (TPOAbs). Sonography was performed according to a strict protocol. We then assessed whether a correlation existed between antibody activity and the 6 sonographic variables of the VESINC system. Hypoechogenicity, heterogeneity, and pseudonodular hypoechoic infiltration were associated with significantly higher TPOAb activity (P Hashimoto thyroiditis.

Interobserver variability of sonography for prediction of placenta accreta.

Science.gov (United States)

Bowman, Zachary S; Eller, Alexandra G; Kennedy, Anne M; Richards, Douglas S; Winter, Thomas C; Woodward, Paula J; Silver, Robert M

2014-12-01

The sensitivity of sonography to predict accreta has been reported as higher than 90%. However, most studies are from single expert investigators. Our objective was to analyze interobserver variability of sonography for prediction of placenta accreta. Patients with previa with and without accreta were ascertained, and images with placental views were collected, deidentified, and placed in random sequence. Three radiologists and 3 maternal-fetal medicine specialists interpreted each study for the presence of accreta and specific findings reported to be associated with its diagnosis. Investigator-specific sensitivity, specificity, and accuracy were calculated. κ statistics were used to assess variability between individuals and types of investigators. A total of 229 sonographic studies from 55 patients with accreta and 56 control patients were examined. Accuracy ranged from 55.9% to 76.4%. Of imaging studies yielding diagnoses, sensitivity ranged from 53.4% to 74.4%, and specificity ranged from 70.8% to 94.8%. Overall interobserver agreement was moderate (mean κ ± SD = 0.47 ± 0.12). κ values between pairs of investigators ranged from 0.32 (fair agreement) to 0.73 (substantial agreement). Average individual agreement ranged from fair (κ = 0.35) to moderate (κ = 0.53). Blinded from clinical data, sonography has significant interobserver variability for the diagnosis of placenta accreta. © 2013 by the American Institute of Ultrasound in Medicine.

MRI, CT, and sonography in the preoperative evaluation of primary tumor extension in malignant pleural mesothelioma; MRT, CT und Sonographie in der praeoperativen Beurteilung der Primaertumorausdehnung beim malignen Pleuramesotheliom

Energy Technology Data Exchange (ETDEWEB)

Layer, G.; Steudel, A.; Schild, H.H. [Radiologische Universitaetsklinik Bonn (Germany); Schmitteckert, H.; Tuengerthal, S.; Schirren, J. [Thoraxklinik Heidelberg-Rohrbach (Germany); Kaick, G. van [Deutsches Krebsforschungszentrum Heidelberg (Germany). Schwerpunkt fuer Onkologische Diagnostik und Therapie

1999-04-01

Purpose: Evaluation of the diagnostic value of the imaging modalities computed tomography (CT), magnetic resonance imaging (MRI), and thoracic sonography in the preoperative staging of malignant pleural mesothelioma. Results: The accuracy rates for CT were 85%, 98%, 83%, 73%, 71%, and 83%. MRI had an accuracy of 71%, 92%, 71%, 83%, 71%, and 96%, the thoracic ultrasound examinations of 76%, 63%, 51%, 60%, 71% and 89%. Conclusions: According to these results CT remains the method of choice in the preoperative assessment of T-stage of malignant pleural mesothelioma. MRI is of nearly the same value, but is not a must. Sonography may be supplementary method for operation planning. (orig./AJ) [Deutsch] Ziel: Evaluation der diagnostischen Wertigkeit der Schnittbildverfahren MRT, CT und Sonographie in der praeoperativen Diagnostik des Pleuramesothelioms. Ergebisse: Die Treffsicherheiten betrugen fuer die genannten anatomischen Regionen im CT 85%, 98%, 83%, 73%, 71%, und 83%, im MRT 71%, 92%, 71%, 83%, 71% bzw. 96%, waehrend sich fuer die thorakale Ultraschalluntersuchung Treffsicherheiten von 76%, 63%, 51%, 60%, 71% und 89% errechneten. Schlussfolgerungen: Die CT bleibt damit das Verfahren erster Wahl in der praeoperativen Diagnostik des malignen Pleuramesothelioms. Eine unbedingte Forderung nach praeoperativer Durchfuehrung einer MRT-Untersuchung ergibt sich nach der vorliegenden Studie nicht. Die Sonographie des Thorax und oberen Abdomens liefert einen wichtigen ergaenzenden Beitrag bei der Planung der Operation des malignen Pleuramesothelioms. (orig./AJ)

OPTIMAL STRATEGIES FOR CONTINUOUS GRAVITATIONAL WAVE DETECTION IN PULSAR TIMING ARRAYS

International Nuclear Information System (INIS)

Ellis, J. A.; Siemens, X.; Creighton, J. D. E.

2012-01-01

Supermassive black hole binaries (SMBHBs) are expected to emit a continuous gravitational wave signal in the pulsar timing array (PTA) frequency band (10 –9 to 10 –7 Hz). The development of data analysis techniques aimed at efficient detection and characterization of these signals is critical to the gravitational wave detection effort. In this paper, we leverage methods developed for LIGO continuous wave gravitational searches and explore the use of the F-statistic for such searches in pulsar timing data. Babak and Sesana have used this approach in the context of PTAs to show that one can resolve multiple SMBHB sources in the sky. Our work improves on several aspects of prior continuous wave search methods developed for PTA data analysis. The algorithm is implemented fully in the time domain, which naturally deals with the irregular sampling typical of PTA data and avoids spectral leakage problems associated with frequency domain methods. We take into account the fitting of the timing model and have generalized our approach to deal with both correlated and uncorrelated colored noise sources. We also develop an incoherent detection statistic that maximizes over all pulsar-dependent contributions to the likelihood. To test the effectiveness and sensitivity of our detection statistics, we perform a number of Monte Carlo simulations. We produce sensitivity curves for PTAs of various configurations and outline an implementation of a fully functional data analysis pipeline. Finally, we present a derivation of the likelihood maximized over the gravitational wave phases at the pulsar locations, which results in a vast reduction of the search parameter space.

Spontaneous Arterial Dissection.

Science.gov (United States)

Brandt, Tobias; Caplan, Louis

2001-09-01

There is no controlled study for the best treatment or management of cervico-cerebral artery dissection (CAD). Rationale initial empiric treatment in acute CAD to prevent secondary embolism is partial thromboplastin time (PTT)-guided anticoagulation by intravenous heparin followed by anticoagulation with warfarin. Carotid surgery for treatment of CAD is not recommended anymore with the possible exception of persisting severe stenosis of the proximal internal carotid artery (ICA). There could be use of carotid angioplasty by balloon dilatation and stenting in selected cases of severe cerebral hemodynamic impairment by bilateral CAD. Duration of secondary prophylaxis by anticoagulation is best guided by Doppler sonography follow-up, and should be continued until normalization of blood flow or until at least 1 year after the vessel is occluded. There is no evidence that pseudoaneurysms increase the risk for embolic complication, and there is no evidence for surgery or continuation of anticoagulation in patients with pseudoaneurysms. Caution should be recommended for exercises that involve excessive head movements (eg, bungee jumping, trampoline jumping, and chiropractic maneuvers). The patient should be informed that recurrent rate is low in nonfamilial cases. Doppler sonography is a low-cost and high-sensitivity method for patients at risk.

Follow-up Sonography after Sonoguided Renal Biopsy

International Nuclear Information System (INIS)

Kim, Hyung Soo; Park, Cheol Min; Cha, In Ho

1996-01-01

To assess ultrasonographic findings and clinical significance after renal biopsy. 174 cases of post-biopsy sonography were studied retrospectively. We classified post-biopsy hematoma on the basis of their size as small (thickness less than 1 cm, length less than 3cm), medium (thickness less than 1cm, length greater than 3 cm), large (thickness greater than 1 cm, length greater than 3 cm). We also compared bleeding parameters (prothrombin time, partial thromboplastin time) and renal function in both cases which had hematoma or not. Total 33 hematomas were found (19%). Small hematoma was observed in 14 cases, medium hematoma in 16 cases, large hematoma in 3 cases. Severe complications requiring prompt therapy occurred in 1 case(0.6%). In 6 cases hematocrit fell by more than 4%, all of these hematomas were observed on US. Severe complications after sonoguided renal biopsy were rare. There was poor correlation between prebiopsybleeding parameter, renal function and post-biopsy hematomas. And sonography is considered as adequate method for follow up of post-biopsy hematoma

Right Ventricular Doppler Echocardiographic Study of Indeterminate Form of Chagas Disease

Directory of Open Access Journals (Sweden)

Rogério Gomes Furtado

2015-03-01

Full Text Available Background: Patients with indeterminate form of Chagas disease/cardiac normality (ICD/CN exhibited normal electrocardiograms and chest X-rays; however, more sophisticated tests detected some degree of morphological and functional changes in the heart. Objective: To assess the prevalence of systolic and diastolic dysfunction of the right ventricle (RV in patients with ICD/CN. Methods: This was a case–control and prevalence study. Using Doppler two-dimensional echocardiography (2D, 92 patients were assessed and divided into two groups: group I (normal, n = 31 and group II (ICD/CN, n = 61. Results: The prevalence of RV systolic dysfunction in patients in groups I and II was as follows: fractional area change (0.0% versus 0.6%, mobility of the tricuspid annulus (0.0% versus 0.0%, and S-wave tissue Doppler (6.4% versus 26.0%, p = 0.016. The prevalence of global disorders such as the right myocardial performance index using tissue Doppler (16.1% versus 27.8%, p = 0.099 and pulsed Doppler (61.3% versus 68%, p = 0.141 and diastolic disorders such as abnormal relaxation (0.0% versus 6.0%, pseudonormal pattern (0.0% versus 0.0%, and restrictive pattern (0.0% versus 0.0% was not statistically different between groups. Conclusion: The prevalence of RV systolic dysfunction was estimated to be 26% (S wave velocity compared with other variables, suggesting incipient changes in RV systolic function in the ICD/CN group.

Suspected leaking abdominal aortic aneurysm: use of sonography in the emergency room.

Science.gov (United States)

Shuman, W P; Hastrup, W; Kohler, T R; Nyberg, D A; Wang, K Y; Vincent, L M; Mack, L A

1988-07-01

To determine the value of sonography in the emergent evaluation of suspected leaking abdominal aortic aneurysms, the authors examined 60 patients in the emergency department using sonography and a protocol involving advance radio notification from the ambulance; arrival of sonographic personnel and equipment in the triage room before patient arrival; and, during other triage activities, rapid sonographic evaluation of the aorta for aneurysm and of the paraaortic region for extraluminal blood. Sonographic findings were correlated with surgical results and clinical outcome. When performed under these circumstances, sonography was accurate in demonstrating presence or absence of aneurysm (98%), but its sensitivity for extraluminal blood was poor (4%). A combination of sonographic confirmation of aneurysm, abdominal pain, and unstable hemodynamic condition resulted in the correct decision to perform emergent surgery in 21 of 22 patients (95%). An abbreviated sonographic examination done in the emergency room can provide accurate, useful information about the presence of aneurysm; this procedure does not significantly delay triage of these patients.

The Continuous Wave Deuterium Demonstrator (CWDD) design and status

Energy Technology Data Exchange (ETDEWEB)

Todd, A.M.M. (Grumman Space and Electronics Corp., Princeton, NJ (United States)); Nightingale, M.P.S. (AEA Industrial Technology, Culham (United Kingdom)); Yule, T.J. (Argonne National Lab., IL (United States))

1992-01-01

The design of the Continuous Wave Deuterium Demonstrator (CWDD) and the status of the fabricated hardware is presented. The CWDD is a high brightness, 352 MHz, CW linear accelerator designed to deliver a 7.54 MeV, 80 mA D[sup [minus

Addison's disease with adrenal enlargement on sonography and computed toimography

International Nuclear Information System (INIS)

Renner, F.; Graninger, W.

1986-01-01

One of the major causes of chronic adrenal insufficiency (Addison's disease) is tuberculous adrenalopathy. Since sonography and computed tomography have become generally available in recent years and are of potential help in the diagnosis of this disease the merits of these methods are discussed in the light of 2 cases of adrenal tuberculosis, followed by a review of the literature. Adrenal calcification is the most significant, although not specific sign of adrenal insufficiency due to tuberculosis. Computed tomography has proven to be the method of choice in the non-invasive diagnosis of tuberculous adrenalopathy and in the monitoring of tuberculostatic treatment in this disease. Sonography is helpful as a preliminary investigation. (Author)

Model experiments on imaging subsurface fracture permeability by pulsed Doppler borehole televiewer; Pulse doppler borehole televiewer ni yoru kiretsu tosuisei hyoka ni kansuru model jikken

Energy Technology Data Exchange (ETDEWEB)

Inagaki, Y; Niitsuma, H [Tohoku University, Sendai (Japan). Faculty of Engineering

1996-05-01

This paper reports model experiments to evaluate flow rates of fluids passing through a fracture by using a Doppler borehole televiewer (DBHTV). A supersonic transducer disposed on a well axis transmits transmission pulses, and a transducer receives scattered waves generated by particulates in water and waves reflected on a well wall. This signal is applied with time gating to extract only the scattered waves from particulates in the vicinity of the well wall. Deriving spectra in the recorded Doppler signal obtains flow velocity components in the direction of the well radius. A model was made with a polyvinylchloride pipe with a diameter of 14.6 cm to simulate a well, to which an aluminum pipe with an inner diameter of 2 mm is connected to be used as a simulated fracture, and mud water is circulated in the pipe. The result of deriving a passed flow volume in this model by integrating flow rate distribution derived by using the above method to a predetermined range in the vicinity of the fracture showed a good proportional relationship with actual flow rate in the simulated fracture. 1 ref., 7 figs.

Clinical significance of a presystolic wave on Doppler examination of the left ventricular outflow tract.

Science.gov (United States)

Joshi, Kamal R; Kabirdas, Deepa; Romero-Corral, Abel; Shah, Mahek; Figueredo, Vincent M; Pressman, Gregg S

2014-11-15

A presystolic wave (PSW) is commonly seen on Doppler examination of the left ventricular outflow tract (LVOT), but is little studied. We conducted a retrospective study to assess the prevalence of the PSW, correlations with various Doppler parameters, and its clinical significance. Two hundred echocardiograms, 100 with ejection fraction (EF) >55% and 100 with EF <45%, were reviewed. Mitral inflow velocities, septal annular velocities, LVOT, and PSW velocities were measured. Major adverse cardiovascular events (MACE [death, heart failure hospitalization, atrial fibrillation, and stroke]) were compared between those with and without a PSW, in both EF groups. Mean age was 58 ± 15 years; 56% were men and 69% were African-American. PSW prevalence was similar between normal (68%) and reduced EF groups (62%). However, its velocity was less in the low EF group (37 ± 10 vs 48 ± 16 cm/s, p <0.0001). In subjects with normal EF PSW velocity correlated with mitral A velocity (rho = 0.43, p = 0.0003). In subjects with reduced EF the association with A velocity was not significant (rho = 0.22, p = 0.09), but there was a significant association with annular a' velocity (rho = 0.38, p = 0.002). Over a mean follow-up of 1.7 ± 0.3 years, 57 subjects (28%) experienced MACE. Those without a PSW had more MACE (39% vs 23%, p = 0.02); PSW absence remained predictive of MACE after adjustment for multiple variables, especially in patients with reduced EF. In conclusion, PSW is common in the LVOT. Its presence and magnitude are associated with measures of atrial contraction. Its absence is associated with increased rates of adverse events, especially in patients with low EF. Copyright © 2014 Elsevier Inc. All rights reserved.

Unenhanced helical CT in the evaluation of the urinary tract in children and young adults following urinary tract reconstruction: comparison with sonography

Energy Technology Data Exchange (ETDEWEB)

Myers, M.T.; Elder, J.S.; Sivit, C.J.; Applegate, K.E. [Dept. of Radiology, Rainbow Babies and Children' s Hospital, Cleveland, OH (United States)

2001-03-01

Purpose. To compare the accuracy of unenhanced, helical CT with sonography for the detection of complications of urinary tract reconstruction. Materials and methods. Forty-six kidneys in 24 patients were examined with CT and sonography. All scans were assessed for ease of renal visualization, presence of renal, ureteral, and bladder calculi, renal scars, hydronephrosis, and abdominal wall hernia. The results of both imaging modalities were independently reported. Results. CT provided excellent visualization of all 46 kidneys, while sonography provided poor visualization of 8 kidneys (17 %) (P < 0.001). CT detected calculi in 10 kidneys, 1 ureter, and 7 bladders. Sonography detected calculi in only 2 kidneys, and 2 bladders. Overall, CT detected significantly more calculi than US (18 vs 4, P = 0.01). CT detected scarring in 15 kidneys, while sonography detected scarring in 10. Hydronephrosis was detected in 6 kidneys by CT and in 8 kidneys by sonography. Three abdominal wall hernias were seen at CT that were not seen at sonography. Conclusion. CT is superior to sonography for the detection of urinary tract calculi and renal scarring. CT will demonstrate abdominal wall hernias that are unsuspected. (orig.)

Observation of gravity waves during the extreme tornado outbreak of 3 April 1974

Science.gov (United States)

Hung, R. J.; Phan, T.; Smith, R. E.

1978-01-01

A continuous wave-spectrum high-frequency radiowave Doppler sounder array was used to observe upper-atmospheric disturbances during an extreme tornado outbreak. The observations indicated that gravity waves with two harmonic wave periods were detected at the F-region ionospheric height. Using a group ray path computational technique, the observed gravity waves were traced in order to locate potential sources. The signals were apparently excited 1-3 hours before tornado touchdown. Reverse ray tracing indicated that the wave source was located at the aurora zone with a Kp index of 6 at the time of wave excitation. The summation of the 24-hour Kp index for the day was 36. The results agree with existing theories (Testud, 1970; Titheridge, 1971; Kato, 1976) for the excitation of large-scale traveling ionospheric disturbances associated with geomagnetic activity in the aurora zone.

Diabetic mastopathy: a diagnostic challenge in breast sonography.

Science.gov (United States)

Moschetta, Marco; Telegrafo, Michele; Triggiani, Vincenzo; Rella, Leonarda; Cornacchia, Ilaria; Serio, Gabriella; Ianora, Amato Antonio Stabile; Angelelli, Giuseppe

2015-02-01

Our purpose was to retrospectively evaluate the incidence and morphologic features of diabetic mastopathy in a group of patients with diabetes, searching for specific sonographic characteristics of diabetic mastopathy. One hundred twenty diabetic patients underwent breast clinical examination, mammography, and sonography. All detected breast lesions were confirmed histopathologically. Breast lesions were found in 11 of the 120 patients (9%), including two cases of invasive ductal carcinomas and nine cases of diabetic mastopathy. In seven of those nine cases (77%), diabetic mastopathy appeared as a hypoechoic solid mass with irregular margins, inhomogeneous echotexture, and marked posterior shadowing. In the other two cases (23%), it appeared as a mildly inhomogeneous, hypoechoic solid mass. Diabetic mastopathy is a diagnostic challenge and needs to be suspected in all patients with diabetes mellitus. Imaging features are nonspecific and highly susggestive on breast sonography in most cases. Core-needle biopsy confirmation remains mandatory for a definitive diagnosis. © 2015 Wiley Periodicals, Inc.

Development of Rayleigh Doppler lidar for measuring middle atmosphere winds

Science.gov (United States)

Raghunath, K.; Patra, A. K.; Narayana Rao, D.

Interpretation of most of the middle and upper atmospheric dynamical and chemical data relies on the climatological description of the wind field Rayleigh Doppler lidar is one instrument which monitors wind profiles continuously though continuity is limited to clear meteorological conditions in the middle atmosphere A Doppler wind lidar operating in incoherent mode gives excellent wind and temperature information at these altitudes with necessary spectral sensitivity It observes atmospheric winds by measuring the spectral shift of the scattered light due to the motions of atmospheric molecules with background winds and temperature by spectral broadening The presentation is about the design and development of Incoherent Doppler lidar to obtain wind information in the height regions of 30-65 km The paper analyses and describes various types of techniques that can be adopted viz Edge technique and Fringe Imaging technique The paper brings out the scientific objectives configuration simulations error sources and technical challenges involved in the development of Rayleigh Doppler lidar The presentation also gives a novel technique for calibrating the lidar

The impact of left ventricular preload reduction on cardiac pulsed doppler indices during hemodialysis and its relation to intra-dialysis hypotension: A pulsed doppler study

International Nuclear Information System (INIS)

Alarrayed, Sameer; Garadah Taysir Said; Alawdi, Abdulhai Ali

2009-01-01

Fluid status in the body plays an important role on left ventricular (LV) filling in patients with end-stage renal disease (ESRD) on regular hemodialysis (HD), and plays a role in intra-dialysis hemodynamic derangement. Fifty-two patients with ESRD on regular HD, including 34 males with a mean age of 45.5 +- 13 years (range 18-72 years), were studied. All patients underwent Echo-pulsed Doppler study before and immediately after a HD session. The Echo Doppler indices noted were: LV cavity dimension and wall thickness, LV ejection fraction (LVEF%), trans-mitral early diastolic filling velocity (E wave), atrial filling diastolic velocity (A wave), E/A ratio, Deceleration Time (DT) of E wave, Isovolumic relaxation time (IVRT), Aortic Velocity Integral (AVI) and Inferior Vena Cava Diameter (VCD) at expiration. Patients were divided into two groups according to the amount of net ultra filtrate loss after HD. Group I comprised of 25 patients with fluid loss of 2 liters. During the HD session, each patient was observed for the development of acute clinical events such as arterial hypotension (systolic BP less than 90 mmHg), chest pain and arrhythmias. There was a significant difference between the two groups in the mean values, pre- and post- HD, of reduction of E wave velocity (p < 0.01), the reduction of E/A ratio (p< 0.05), the increment in DT of E wave (p< 0.05), the reduction in AVI (p< 0.01) and the reduction of VCD (p< 0.05). There was no significant difference between the groups in the reduction of A wave velocity and the reduction of IVRT. Among the study patients, 11 (21%) developed systolic hypo-tension during HD. The pre-dialysis mean values of E/A ratio and DT of E wave in patients who developed hypotension compared to those who did not was 0.7 +- 0.2 vs 1.1 +- 0.2.1 (p< 0.001) and 246 +- 40 vs 224 +- 34 msec (p< 0.05), respectively. Our study suggests that preload reduction in patients with ESRD on regular HD is directly proportional to the reduction of left

Early diagnosis of hygroma cervicis in a fetus. Sonographic, pulsed Doppler echographic and MRI findings

Energy Technology Data Exchange (ETDEWEB)

Date, Kenjiro; Nagai, Toru; Sera, Kyoko and others

1986-07-01

A fetus was diagnosed as having hygroma cervicis (HC) with sonography. Sonographic features at 23 weeks of gestation were symmetrical echo free spaces of the head suggestive of a giant solid tumor (HC) and single umbilical artery. When umbilical circulation of the single umbilical artery was examined using pulsed Doppler echography, high S/D ratios were seen. MRI clearly visualized a mass surrounding the head as an abnormal signal intensity. Pregnancy was terminated in the second trimester. A male stillborn baby weighing 1,440 g had multiple anomalies associated with cervical lymphangioma. Elevated amniotic and intracystic levels of AFP were not seen. A review of the literature shows the relationship between HC and Turner syndrome. However, because the present case was a male baby, hereditary disease may be related to the occurrence of HC. (Namekawa, K.).

Transition from Spirals to Defect-Mediated Turbulence Driven by a Doppler Instability

International Nuclear Information System (INIS)

Ouyang, Qi; Swinney, Harry L.; Li, Ge

2000-01-01

A transition from rotating chemical spirals to turbulence is observed in experiments on the Belousov-Zhabotinsky reaction. The transition occurs when the waves near the spiral tip spontaneously break, generating defects. Measurements reveal that this defect-mediated turbulence is caused by the Doppler effect on the traveling waves. The observations are in good accord with numerical simulations and theory. (c) 2000 The American Physical Society

Rapidly tunable continuous-wave optical parametric oscillator pumped by a fiber laser

NARCIS (Netherlands)

Klein, M.E.; Gross, P.; Boller, Klaus J.; Auerbach, M.; Wessels, P.; Fallnich, C.

2003-01-01

We report on rapid, all-electronically controlled wavelength tuning of a continuous-wave (cw) optical parametric oscillator (OPO) pumped by an ytterbium fiber laser. The OPO is singly resonant for the signal wave and consists of a 40-mm-long periodically poled lithium niobate crystal in a

Experimental verification of the inverse Doppler effect in negative-index material

Science.gov (United States)

Feng, Lie; Chen, Jiabi; Wang, Yan; Geng, Tao; Zhuang, Songlin

2010-10-01

μResearch of negative-index material (NIM) is a very hot developing research field in recent years. NIM is also called left-handed material (LHM), in which the electric field [see manuscript], the magnetic field [see manuscript] and the wave vector [see manuscript] are not composed of a set of right-handed coordinates but a set of left-handed coordinates. Thus the action of electromagnetic waves in both left-handed material and right-handed material is just the opposite, for instance, the negative refraction phenomenon, the inverse Doppler effect and so on. Here we report the explicit result of the inverse Doppler effect through a photonic crystal (PC) prism at 10.6m wavelength for the first time, and the result we get from the experiment is much similar to the theoretical analysis we have deduced before. During the experiment, the CO2 laser is used as a light source, and the PC prism is used as a sample, which can move a tiny distance (1mm) uniformly with a translating stage. Based on the method of optical heterodyne, we let the emergent light from the output surface of PC prism and the reference light from light source interfere at the surface of the detector. When the translating stage moves towards the detector, the optical paths in the PC prism will be changed, and then the Doppler frequency shift will be generated. Though several different samples have been tested repeatedly, the results we get are extraordinarily similar. So we can be sure that the inverse Doppler effect really exists in the NIM at optical frequencies. To our best knowledge, this is the only experimental verification of the inverse Doppler effect in the NIM at optical frequencies at home and aboard.

Duplex sonography in portal hypertension

International Nuclear Information System (INIS)

Kwon, Hyuk Po; Jang, J. C.; Park, B. H.

1990-01-01

We measure the diameter and blood velocity of the portal vein in 50 patients with cirrhosis of the liver and 40 healthy subjects, and calculated cross sectional area, mean blood flow velocity, blood flow volume and congestion index. In patients with cirrhosis of the liver, the cross sectional area of the portal vein was significantly increased: the mean blood flow volume was significantly reduced; the blood flow volume was significantly increased; the congestion index of the portal vein was significantly increased. Duples sonography may play an important role in the diagnosis of portal hypertension

Continuous waves probing in dynamic acoustoelastic testing

Science.gov (United States)

Scalerandi, M.; Gliozzi, A. S.; Ait Ouarabi, M.; Boubenider, F.

2016-05-01

Consolidated granular media display a peculiar nonlinear elastic behavior, which is normally analysed with dynamic ultrasonic testing exploiting the dependence on amplitude of different measurable quantities, such as the resonance frequency shift, the amount of harmonics generation, or the break of the superposition principle. However, dynamic testing allows measuring effects which are averaged over one (or more) cycles of the exciting perturbation. Dynamic acoustoelastic testing has been proposed to overcome this limitation and allow the determination of the real amplitude dependence of the modulus of the material. Here, we propose an implementation of the approach, in which the pulse probing waves are substituted by continuous waves. As a result, instead of measuring a time-of-flight as a function of the pump strain, we study the dependence of the resonance frequency on the strain amplitude, allowing to derive the same conclusions but with an easier to implement procedure.

The value of intrarenal resistive index in autosomal dominant polycystic kidney disease

International Nuclear Information System (INIS)

Lee, Young Rae; Lee, Kyu Beck; Park, Hae Won

1998-01-01

The purpose of this study was to determine the value of the intrarenal resistive index(RI), measured by Doppler sonography, in order to assess intrarenal vascular resistance in autosomal dominant polycystic kidney disease (ADPKD) patients. In 26 patients with ADPKD, RI was measured by Doppler sonography and correlated with the presence of hypertension, renal function (creatinine clearance) and anatomical renal severity index (RSI), thus indicating renal morphologic abnormalities during Bmode sonography. RI was significantly higher in 18 hypertensive ADPKD patients (0.64±0.65) (Mean±1SD;range:0.52-0.74) than in eight normotensive patients (0.59± 0.50) (0.48-0.64) (p<0.05). Statistically significant inverse correlation was found between RI values and creatinine clearance (r=3D-0.45, p<0.05), and statistically significant correlation was found between RI values and RSI, indicating the degree of renal parenchymal involvement. RI correlates with the development of hypertension, renal function and renal morphologic abnormality scoring by RSI during B-mode Doppler sonography, and measured in this way may thus be used to assess renal vascular resistance in ADPKD patients.=20

The Significance of Brain Transcranial Sonography in Burning Mouth Syndrome: a Pilot Study.

Science.gov (United States)

Zavoreo, Iris; Vučićević, Vanja; Boras; Zadravec, Dijana; Bašić, Vanja; Kes; Ciliga, Dubravka; Gabrić, Dragana

2017-03-01

Burning mouth syndrome (BMS) is a chronic disorder which is affecting mostly postmenopausal women and is characterized by burning symptoms in the oral cavity on the clinically healthy oral mucosa. Also, the results of previous studies suggested a possible role of peripheral and/or central neurological disturbances in these patients. The aim of this study was to analyze patients with burning mouth syndrome using transcranial sonography. By use of transcranial sonography of the brain parenchyma, substantia nigra , midbrain raphe and brain nucleus were evaluated in 20 patients with BMS (64.7±12.3 years) and 20 controls with chronic pain in the lumbosacral region (61.5±15). Statistical analysis was performed by use of Student t test with significance set at pburning mouth syndrome might reflect central disturbances within this syndrome. Burning Mouth Syndrome; Transcranial Sonography; substantia nigra; Midbrain Raphe Nuclei; Red Nucleus.

Comparison the percentage of detection of periarthritis in patients with rheumatoid arthritis using clinical examination or ultrasound methods

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Hadi Karimzadeh

2016-01-01

Full Text Available Background: This study aimed to compare the percentage of detection of periarthritis in patients with rheumatoid arthritis using clinical examination and ultrasound methods. Materials and Methods: This study is a cross-sectional study which was conducted in Al-Zahra Hospital (Isfahan, Iran during 2014–2015. In our study, ninety patients were selected based on the American College of Rheumatology 2010 criteria. All patients were examined by a rheumatologist to find the existence of effusion, and the data were filled in the checklist. The ultrasonography for detecting effusion in periarticular structures was done by an expert radiologist with two methods, including high-resolution ultrasonography and power Doppler. The percentage of effusion existence found by physical examination was compared by sonography, and the Chi-square and t-tests were used for data analysis. Results: The percentage of effusion found in areas with physical examination by rheumatologist was lower than the frequency distribution of effusions found by sonography (8.3% VS 14.2% (P < 0.001. In sonography, rotator cuff tendonitis is the most common periarthritis. Other findings in sonography were biceps tendinitis (10 cases, wrist tendonitis (13 cases, olecranon bursitis (9 cases, golfers elbow (4 cases, tennis elbow (4 cases, trochanteric bursitis (6 cases, anserine bursitis (6 cases, prepatellar bursitis (11 cases, and ankle tendonitis (7 cases. Tenderness on physical examination was found in 15% of the cases, and the evidence of periarthritis was found in 21/7% through sonography (P < 0.001 and 34% through Doppler sonography (P < 0.001. Conclusion: The percentage of periarthritis detection by ultrasonography and power Doppler sonography was higher than clinical examination. Hence, the ultrasonography is more accurate than physical examination.

Comparison of sonography and venography in the diagnosis of lower extremity deep venous thrombosis

International Nuclear Information System (INIS)

Mostbeck, G.H.; Kettenbach, J.; Henk, C.

1993-01-01

In recent years, non-invasive sonographic techniques [real-time ultrasound (US), duplex ultrasonography (DU) and color-coded duplex sonography (CCDS)] have increased in importance for the diagnosis of lower extremity deep venous thrombosis. To ascertain the accuracy and limitations of these techniques prospectively, various studies have been performed to compare sonography with venography. This review deals with basic methodologic considerations when two imaging methds are compared and describes the features of deep venous thrombosis seen on US, DU and CCDS. Reports comparing sonography and phlebography for the diagnosis of deep venous thrombosis are presented and discussed. The advantages and limitations of US, DU and CCDS for the diagnosis of iliac, femoral, popliteal and infrapopliteal venous thrombosis are compared with those of venography, and controversial areas are touched on. (orig.) [de

A fiber optic Doppler sensor and its application in debonding detection for composite structures.

Science.gov (United States)

Li, Fucai; Murayama, Hideaki; Kageyama, Kazuro; Meng, Guang; Ohsawa, Isamu; Shirai, Takehiro

2010-01-01

Debonding is one of the most important damage forms in fiber-reinforced composite structures. This work was devoted to the debonding damage detection of lap splice joints in carbon fiber reinforced plastic (CFRP) structures, which is based on guided ultrasonic wave signals captured by using fiber optic Doppler (FOD) sensor with spiral shape. Interferometers based on two types of laser sources, namely the He-Ne laser and the infrared semiconductor laser, are proposed and compared in this study for the purpose of measuring Doppler frequency shift of the FOD sensor. Locations of the FOD sensors are optimized based on mechanical characteristics of lap splice joint. The FOD sensors are subsequently used to detect the guided ultrasonic waves propagating in the CFRP structures. By taking advantage of signal processing approaches, features of the guided wave signals can be revealed. The results demonstrate that debonding in the lap splice joint results in arrival time delay of the first package in the guided wave signals, which can be the characteristic for debonding damage inspection and damage extent estimation.

3D atom microscopy in the presence of Doppler shift

Science.gov (United States)

Rahmatullah; Chuang, You-Lin; Lee, Ray-Kuang; Qamar, Sajid

2018-03-01

The interaction of hot atoms with laser fields produces a Doppler shift, which can severely affect the precise spatial measurement of an atom. We suggest an experimentally realizable scheme to address this issue in the three-dimensional position measurement of a single atom in vapors of rubidium atoms. A three-level Λ-type atom-field configuration is considered where a moving atom interacts with three orthogonal standing-wave laser fields and spatial information of the atom in 3D space is obtained via an upper-level population using a weak probe laser field. The atom moves with velocity v along the probe laser field, and due to the Doppler broadening the precision of the spatial information deteriorates significantly. It is found that via a microwave field, precision in the position measurement of a single hot rubidium atom can be attained, overcoming the limitation posed by the Doppler shift.

Nutcracker Syndrome Accompanying Pelvic Congestion Syndrome; Color Doppler Sonography and Multislice CT Findings: A Case Report

International Nuclear Information System (INIS)

Inal, Mikail; Karadeniz Bilgili, Mihrace Yasemin; Sahin, Safa

2014-01-01

Nutcracker syndrome (NCS) is a rare pathology, caused by compression of the left renal vein (LRV) between the abdominal aorta (AA) and the superior mesenteric artery (SMA), due to reduction of the angle between AA and SMA. This leads to LRV varices, left gonadal vein varices and therefore, the pelvic congestion syndrome. For this reason, coexistence of NCS and pelvic congestion syndrome has been described. It manifests by hematuria, proteinuria, and nonspecific pelvic pain secondary to pelvic congestion, dyspareunia and persistent genital arousal. We report a 27-year-old woman who experienced hematuria and left flank pain. The diagnosis of NCS accompanied by pelvic congestion syndrome was missed initially, but later on the diagnosis was made by color Doppler ultrasound, abdominal computed tomography (CT) and CT angiography that were later performed. She refused interventional and surgical treatments, and was lost to follow up

Evaluating the cardiac function of duchenne muscular dystrophy with Doppler Tei index

International Nuclear Information System (INIS)

Yao Fengjuan; Zheng Ju; Lu Kun; Liu Donghong; Wu Miaoling; Lin Hong; Zhang Cheng; Yu Hongkui

2007-01-01

Objective: To evaluate the cardiac function of early Duchenne muscular dystrophy (DMD) by left ventricular ejection fraction (LVEF) and pulse Doppler Tei index. Methods: Twenty-eight DMD patients and fifteen normal people were studied. LVEF, E/A and Tei index were measured and calculated by M-mode and Pulse wave Doppler respectively. Results: Compared with control group, Tei index and IRT were significantly high, and there were not significant difference in LVEF(%) and E/A. Conclusion: Tei index was valuable in assessing cardiac function of early DMD. (authors)

Usefulness of sonography in women less than 35 years old with palpable breast masses

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyun Ju; Chung, Hyun Ung; Park, Jin Gyoon; Seo, Jeong Jin; Kang, Heoung Keun; Kim, Jae Kyu; Chung, Hyon De [Chonnam National University College of Medicine, Gwangju (Korea, Republic of)

1994-12-15

To assess the usefulness of sonography in the evaluation of palpable mass in patients less than 35 years old,the breast sonograms and mammograms of 105 histopathologically proved cases were retrospectively reviewed. Breast parenchymal patterns on mammogram, sensitivity of sonography and mammography in the diagnosis of palpable breast masses, and sonographic findings of breast masses were analyzed. Grade IV breast parenchymal pattern was demonstrated in 44 of 76 mammogram (57.9%). The incidence of Grade IV pattern increased, as the patients' age became younger. The sensitivity of sonography (81.3%) was higher than that of mammography (45.3%) in the evaluation of the benign breast lesions. However, the sensitivity of both modalities were nearly equal (66.7% and 58.3% respectively) in the evaluation of the breast cancers. Sonographic findings of fibroadenoma included oval,well defined border, smooth contour, weak homogeneous internal echoes, posterior sonic enhancement, and bilateral shadows. On the other hand, breast cancer exhibited poorly defined border, irregular contour, and inhomogeneous hypoechoic mass with posterior sonic attenuation. In summary, sonography was useful in the evaluation of the palpable breast mass in women less than 35 years old. Choreoathetotic sonographic findings might help the differential diagnosis of breast masses

Usefulness of sonography in women less than 35 years old with palpable breast masses

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyun Ju; Chung, Hyun Ung; Park, Jin Gyoon; Seo, Jeong Jin; Kang, Heoung Keun; Kim, Jae Kyu; Chung, Hyon De [Chonnam National University College of Medicine, Gwangju (Korea, Republic of)

1994-12-15

To assess the usefulness of sonography in the evaluation of palpable mass in patients less than 35 years old,the breast sonograms and mammograms of 105 histopathologically proved cases were retrospectively reviewed. Breast parenchymal patterns on mammogram, sensitivity of sonography and mammography in the diagnosis of palpable breast masses, and sonographic findings of breast masses were analyzed. Grade IV breast parenchymal pattern was demonstrated in 44 of 76 mammogram (57.9%). The incidence of Grade IV pattern increased, as the patients' age became younger. The sensitivity of sonography (81.3%) was higher than that of mammography (45.3%) in the evaluation of the benign breast lesions. However, the sensitivity of both modalities were nearly equal (66.7% and 58.3% respectively) in the evaluation of the breast cancers. Sonographic findings of fibroadenoma included oval,well defined border, smooth contour, weak homogeneous internal echoes, posterior sonic enhancement, and bilateral shadows. On the other hand, breast cancer exhibited poorly defined border, irregular contour, and inhomogeneous hypoechoic mass with posterior sonic attenuation. In summary, sonography was useful in the evaluation of the palpable breast mass in women less than 35 years old. Choreoathetotic sonographic findings might help the differential diagnosis of breast masses

Radar observations of ion cyclotron waves associated with two barium shaped-charge releases

International Nuclear Information System (INIS)

Providakes, J.; Swartz, W.E.; Kelley, M.C.; Djuth, F.T.; Noble, S.; Jost, R.J.

1990-01-01

A 50-MHz Doppler radar interferometer and a 138-MHz Doppler radar were operated from Kennedy Space Center to study 3-m and 1-m plasma waves associated with two shaped-charged barium releases from Wallops Island, Virginia, on May 13, 1986. During the first release, interferometer and Doppler power spectral studies showed the existence of short-lived ( + EIC waves were unstable for field-aligned electron drifts greater than 0.7υ the at the altitude of 510 km in a multispecies (O + , NO + , or similarly O 2 + ) ionospheric plasma. The authors interpret the 30-Hz waves seen by the two radars far above the release as strong electrostatic ion cyclotron waves generated by intense field-aligned currents associated with the barium stream acting like an MHD generator coupled to the ionospheres

Nonlinear wave propagation in discrete and continuous systems

Science.gov (United States)

Rothos, V. M.

2016-09-01

In this review we try to capture some of the recent excitement induced by a large volume of theoretical and computational studies addressing nonlinear Schrödinger models (discrete and continuous) and the localized structures that they support. We focus on some prototypical structures, namely the breather solutions and solitary waves. In particular, we investigate the bifurcation of travelling wave solution in Discrete NLS system applying dynamical systems methods. Next, we examine the combined effects of cubic and quintic terms of the long range type in the dynamics of a double well potential. The relevant bifurcations, the stability of the branches and their dynamical implications are examined both in the reduced (ODE) and in the full (PDE) setting. We also offer an outlook on interesting possibilities for future work on this theme.

Explaining Polarization Reversals in STEREO Wave Data

Science.gov (United States)

Breneman, A.; Cattell, C.; Wygant, J.; Kersten, K.; Wilson, L, B., III; Dai, L.; Colpitts, C.; Kellogg, P. J.; Goetz, K.; Paradise, A.

2012-01-01

Recently Breneman et al. reported observations of large amplitude lightning and transmitter whistler mode waves from two STEREO passes through the inner radiation belt (Lpaper. We show, with a combination of observations and simulated wave superposition, that these polarization reversals are due to the beating of an incident electromagnetic whistler mode wave at 21.4 kHz and linearly polarized, symmetric lower hybrid sidebands Doppler-shifted from the incident wave by +/-200 Hz. The existence of the lower hybrid waves is consistent with the parametric decay mechanism of Lee and Kuo whereby an incident whistler mode wave decays into symmetric, short wavelength lower hybrid waves and a purely growing (zero-frequency) mode. Like the lower hybrid waves, the purely growing mode is Doppler-shifted by 200 Hz as observed on STEREO. This decay mechanism in the upper ionosphere has been previously reported at equatorial latitudes and is thought to have a direct connection with explosive spread F enhancements. As such it may represent another dissipation mechanism of VLF wave energy in the ionosphere and may help to explain a deficit of observed lightning and transmitter energy in the inner radiation belts as reported by Starks et al.

10 MHz b-scan sonography of the cervical carotid arteries

International Nuclear Information System (INIS)

Kuhn, F.P.; Kraemer, G.; Bauer, R.; Klotter, H.J.; Mainz Univ.; Mainz Univ.

1984-01-01

Two hundred and eighty-two consecutive patients with cerebro-vascular insufficiency, with non-specific neurological symptoms or asymptomatic murmurs, were examined prospectively by two-dimensional high resolution 10 MHz B-scan real time sonography. Arteriosclerotic plaques were usually semi-circular (77%), of high amplitude (64%) and homogeneous (80%). Ulcerating plaques were correctly diagnosed in only three out of eight cases demonstrated angiographically. So far there has been no definite relationship between the appearance of the plaques and clinical symptoms. Compared with arteriography (170 examinations) the specificity of sonography was 98% (62/63), the sensitivity for plaques was 100% (50/50), for stenoses it was 63% (5/8) to 93% (14/15), for occlusions it was 76% (13/17). The indications and drawbacks of the method are discussed. (orig.) [de

Upper Abdominal Ultra-Sonography Findings in HIV Patients at ...

African Journals Online (AJOL)

Design: A descriptive cross-sectional study. Setting: Kenyatta National Hospital and the Defence Forces Memorial Hospital, Nairobi, Kenya. Subjects: HIV infected patients referred for upper abdominal sonography within the study duration of eight months. Results: Two hundred and seventy three (273) patients were ...

Doppler Tomography

Science.gov (United States)

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 accretion disc or stream. I discuss all of these and finish with some musings on possible future directions for the method. At the end I include a tabulation of Doppler maps published in refereed journals.

Plantar fascia softening in plantar fasciitis with normal B-mode sonography.

Science.gov (United States)

Wu, Chueh-Hung; Chen, Wen-Shiang; Wang, Tyng-Guey

2015-11-01

To investigate plantar fascia elasticity in patients with typical clinical manifestations of plantar fasciitis but normal plantar fascia morphology on B-mode sonography. Twenty patients with plantar fasciitis (10 unilateral and 10 bilateral) and 30 healthy volunteers, all with normal plantar fascia morphology on B-mode sonography, were included in the study. Plantar fascia elasticity was evaluated by sonoelastographic examination. All sonoelastograms were quantitatively analyzed, and less red pixel intensity was representative of softer tissue. Pixel intensity was compared among unilateral plantar fasciitis patients, bilateral plantar fasciitis patients, and healthy volunteers by one-way ANOVA. A post hoc Scheffé's test was used to identify where the differences occurred. Compared to healthy participants (red pixel intensity: 146.9 ± 9.1), there was significantly less red pixel intensity in the asymptomatic sides of unilateral plantar fasciitis (140.4 ± 7.3, p = 0.01), symptomatic sides of unilateral plantar fasciitis (127.1 ± 7.4, p plantar fasciitis (129.4 ± 7.5, p plantar fascia thickness or green or blue pixel intensity among these groups. Sonoelastography revealed that the plantar fascia is softer in patients with typical clinical manifestations of plantar fasciitis, even if they exhibit no abnormalities on B-mode sonography.

Achilles tendon (TA) size and power Doppler ultrasound (PD) changes compared to MRI: A preliminary observational study

International Nuclear Information System (INIS)

Richards, P.J.; Dheer, A.K.; McCall, I.M.

2001-01-01

AIM: To assess whether abnormal Achilles tendon (TA) magnetic resonance imaging (MRI) and spectral ultrasound (US) features have associated development of microvascular power Doppler (PD) flow. MATERIALS AND METHODS: In a prospective, controlled and blinded study six patients with TA symptoms were compared to five with other ankle abnormalities. Two radiologists independently measured the mean maximal anteroposterior diameter on MRI and conventional US (categorized as normal 1.6 cm), assessed morphology and studied the vessels using power Doppler. They formed a consensus over discrepancies. Sonography of the contralateral side within 24 h was used as a control. RESULTS: Twenty-one tendons in six women and five men, aged 45-77 years (mean 57.6 years), were examined, 12 tendons were of normal US morphology and size ( 0.74). Of the 12 tendons studied by MRI five were normal, seven tendons were enlarged, five of which had a proportionate increase in PD flow at the margin on the deep surface and four also had vessels in the centre of the tendon. All five of these tendons had high signal on T2-weighting (T2W). Of the two mildly enlarged tendons of intermediate signal on T1 and T2W, one showed PD flow and the other did not. CONCLUSIONS: In patients with TA disease power Doppler ultrasound shows proliferation of vessels in enlarged, abnormal tendons demonstrated on MRI and standard ultrasound, in the absence of definite tears. Richards, P.J. Dheer, A.K. and McCall, I.M. (2001)

The role of sonography in patients with breast cancer presenting as an axillary mass

International Nuclear Information System (INIS)

Park, Sun Young; Kim, Eun Kyung; Oh, Ki Keun; Lee, Kyong Sik; Park, Byeong Woo

2002-01-01

To compare sonography and mammography in terms of their diagnostic value in breast cancer cases which initially presented as an axillary mass without a palpable mass or other clinical symptoms. Seven patients with enlarged axillary lymph nodes who first presented with no evidence of palpable breast lesions and who underwent both mammography and sonography were enrolled in this study. In six of the seven, the presence of metastatic adenocarcinoma was confirmed preoperatively by axillary needle aspiration biopsy; in four, subsequent sonographically guided breast core biopsy performed after careful examination of the primary site indicated that primary breast cancer was present. In each case, the radiologic findings were evaluated by both breast sonography and mammography. Breast lesions were detected mammographically in four of seven cases (57%); in three of the four, the lesion presented as a mass, and in one as microcalcification. In three of these four detected cases, fatty or scattered fibroglandular breast parenchyma was present; in one, the parenchyma was dense. In the three cases in which lesions were not detected, mammography revealed the presence of heterogeneously dense parenchyma. Breast sonography showed that lesions were present in six of seven cases (86%); in the remaining patient, malignant microcalcification was detected at mammography. Final pathologic examination indicated that all breast lesions except one, which was a ductal carcinoma in situ, with microinvasion, were infiltrating ductal carcinomas whose size ranged from microscopic to greater than 3 cm. At the time of this study, all seven patients were alive and well, having been disease free for up to 61 months after surgery. In women with a palpable axillary mass confirmed as metastatic adenocarcinoma, breast sonography may be a valuable adjunct to mammography

Continuity Conditions on Schrodinger Wave Functions at Discontinuities of the Potential.

Science.gov (United States)

Branson, David

1979-01-01

Several standard arguments which attempt to show that the wave function and its derivative must be continuous across jump discontinuities of the potential are reviewed and their defects discussed. (Author/HM)

Neuronal Networks in Children with Continuous Spikes and Waves during Slow Sleep

Science.gov (United States)

Siniatchkin, Michael; Groening, Kristina; Moehring, Jan; Moeller, Friederike; Boor, Rainer; Brodbeck, Verena; Michel, Christoph M.; Rodionov, Roman; Lemieux, Louis; Stephani, Ulrich

2010-01-01

Epileptic encephalopathy with continuous spikes and waves during slow sleep is an age-related disorder characterized by the presence of interictal epileptiform discharges during at least greater than 85% of sleep and cognitive deficits associated with this electroencephalography pattern. The pathophysiological mechanisms of continuous spikes and…

A Wave-Optics Approach to Paraxial Geometrical Laws Based on Continuity at Boundaries

Science.gov (United States)

Linares, J.; Nistal, M. C.

2011-01-01

We present a derivation of the paraxial geometrical laws starting from a wave-optics approach, in particular by using simple continuity conditions of paraxial spherical waves at boundaries (discontinuities) between optical media. Paraxial geometrical imaging and magnification laws, under refraction and reflection at boundaries, are derived for…

Doppler velocity measurements from large and small arteries of mice

Science.gov (United States)

Reddy, Anilkumar K.; Madala, Sridhar; Entman, Mark L.; Michael, Lloyd H.; Taffet, George E.

2011-01-01

With the growth of genetic engineering, mice have become increasingly common as models of human diseases, and this has stimulated the development of techniques to assess the murine cardiovascular system. Our group has developed nonimaging and dedicated Doppler techniques for measuring blood velocity in the large and small peripheral arteries of anesthetized mice. We translated technology originally designed for human vessels for use in smaller mouse vessels at higher heart rates by using higher ultrasonic frequencies, smaller transducers, and higher-speed signal processing. With these methods one can measure cardiac filling and ejection velocities, velocity pulse arrival times for determining pulse wave velocity, peripheral blood velocity and vessel wall motion waveforms, jet velocities for the calculation of the pressure drop across stenoses, and left main coronary velocity for the estimation of coronary flow reserve. These noninvasive methods are convenient and easy to apply, but care must be taken in interpreting measurements due to Doppler sample volume size and angle of incidence. Doppler methods have been used to characterize and evaluate numerous cardiovascular phenotypes in mice and have been particularly useful in evaluating the cardiac and vascular remodeling that occur following transverse aortic constriction. Although duplex ultrasonic echo-Doppler instruments are being applied to mice, dedicated Doppler systems are more suitable for some applications. The magnitudes and waveforms of blood velocities from both cardiac and peripheral sites are similar in mice and humans, such that much of what is learned using Doppler technology in mice may be translated back to humans. PMID:21572013

Laser Doppler flowmetry for measurement of laminar capillary blood flow in the horse

Science.gov (United States)

Adair, Henry S., III

1998-07-01

Current methods for in vivo evaluation of digital hemodynamics in the horse include angiography, scintigraphy, Doppler ultrasound, electromagnetic flow and isolated extracorporeal pump perfused digit preparations. These techniques are either non-quantifiable, do not allow for continuous measurement, require destruction of the horse orare invasive, inducing non- physiologic variables. In vitro techniques have also been reported for the evaluation of the effects of vasoactive agents on the digital vessels. The in vitro techniques are non-physiologic and have evaluated the vasculature proximal to the coronary band. Lastly, many of these techniques require general anesthesia or euthanasia of the animal. Laser Doppler flowmetry is a non-invasive, continuous measure of capillary blood flow. Laser Doppler flowmetry has been used to measure capillary blood flow in many tissues. The principle of this method is to measure the Doppler shift, that is, the frequency change that light undergoes when reflected by moving objects, such as red blood cells. Laser Doppler flowmetry records a continuous measurement of the red cell motion in the outer layer of the tissue under study, with little or no influence on physiologic blood flow. This output value constitutes the flux of red cells and is reported as capillary perfusion units. No direct information concerning oxygen, nutrient or waste metabolite exchange in the surrounding tissue is obtained. The relationship between the flowmeter output signal and the flux of red blood cells is linear. The principles of laser Doppler flowmetry will be discussed and the technique for laminar capillary blood flow measurements will be presented.

A Pedestrian Detection Scheme Using a Coherent Phase Difference Method Based on 2D Range-Doppler FMCW Radar

Science.gov (United States)

Hyun, Eugin; Jin, Young-Seok; Lee, Jong-Hun

2016-01-01

For an automotive pedestrian detection radar system, fast-ramp based 2D range-Doppler Frequency Modulated Continuous Wave (FMCW) radar is effective for distinguishing between moving targets and unwanted clutter. However, when a weak moving target such as a pedestrian exists together with strong clutter, the pedestrian may be masked by the side-lobe of the clutter even though they are notably separated in the Doppler dimension. To prevent this problem, one popular solution is the use of a windowing scheme with a weighting function. However, this method leads to a spread spectrum, so the pedestrian with weak signal power and slow Doppler may also be masked by the main-lobe of clutter. With a fast-ramp based FMCW radar, if the target is moving, the complex spectrum of the range- Fast Fourier Transform (FFT) is changed with a constant phase difference over ramps. In contrast, the clutter exhibits constant phase irrespective of the ramps. Based on this fact, in this paper we propose a pedestrian detection for highly cluttered environments using a coherent phase difference method. By detecting the coherent phase difference from the complex spectrum of the range-FFT, we first extract the range profile of the moving pedestrians. Then, through the Doppler FFT, we obtain the 2D range-Doppler map for only the pedestrian. To test the proposed detection scheme, we have developed a real-time data logging system with a 24 GHz FMCW transceiver. In laboratory tests, we verified that the signal processing results from the proposed method were much better than those expected from the conventional 2D FFT-based detection method. PMID:26805835

A Pedestrian Detection Scheme Using a Coherent Phase Difference Method Based on 2D Range-Doppler FMCW Radar

Directory of Open Access Journals (Sweden)

Eugin Hyun

2016-01-01

Full Text Available For an automotive pedestrian detection radar system, fast-ramp based 2D range-Doppler Frequency Modulated Continuous Wave (FMCW radar is effective for distinguishing between moving targets and unwanted clutter. However, when a weak moving target such as a pedestrian exists together with strong clutter, the pedestrian may be masked by the side-lobe of the clutter even though they are notably separated in the Doppler dimension. To prevent this problem, one popular solution is the use of a windowing scheme with a weighting function. However, this method leads to a spread spectrum, so the pedestrian with weak signal power and slow Doppler may also be masked by the main-lobe of clutter. With a fast-ramp based FMCW radar, if the target is moving, the complex spectrum of the range- Fast Fourier Transform (FFT is changed with a constant phase difference over ramps. In contrast, the clutter exhibits constant phase irrespective of the ramps. Based on this fact, in this paper we propose a pedestrian detection for highly cluttered environments using a coherent phase difference method. By detecting the coherent phase difference from the complex spectrum of the range-FFT, we first extract the range profile of the moving pedestrians. Then, through the Doppler FFT, we obtain the 2D range-Doppler map for only the pedestrian. To test the proposed detection scheme, we have developed a real-time data logging system with a 24 GHz FMCW transceiver. In laboratory tests, we verified that the signal processing results from the proposed method were much better than those expected from the conventional 2D FFT-based detection method.

Electromagnetic Cyclotron Waves in the Solar Wind: Wind Observation and Wave Dispersion Analysis

Science.gov (United States)

Jian, L. K.; Moya, P. S.; Vinas, A. F.; Stevens, M.

2016-01-01

Wind observed long-lasting electromagnetic cyclotron waves near the proton cyclotron frequency on 11 March 2005, in the descending part of a fast wind stream. Bi-Maxwellian velocity distributions are fitted for core protons, beam protons, and alpha-particles. Using the fitted plasma parameters we conduct kinetic linear dispersion analysis and find ion cyclotron and/or firehose instabilities grow in six of 10 wave intervals. After Doppler shift, some of the waves have frequency and polarization consistent with observation, thus may be correspondence to the cyclotron waves observed.

Pulsed and Tissue Doppler Echocardiographic Changes in Patients with Thalassemia Major

Directory of Open Access Journals (Sweden)

Taysir S. Garadah

2010-01-01

Full Text Available Background Doppler echocardiographic studies of left ventricle (LV systolic and diastolic function in patients with β-Thalassemia Major (β-TM had shown different patterns of systolic and diastolic dysfunction. Aim This cross-sectional study was designed to study the LV systolic and diastolic function in patients with β-TM using Pulsed Doppler (PD and Tissue Doppler (TD echocardiography. Methods All patients were evaluated clinically and by echocardiography, The study included patients with β-TM (n = 38, age 15.7 ± 8.9 years compared with an age-matched control group (n = 38, age 15.9 ± 8.9 years. The pulse Doppler indices were normalized for age and heart rate. Results Compared with control patients, M-Mode showed that patients with β-TM have thicker LV septal wall index (0.659 ± 0.23 vs. 0.446 ± 0.219 cm, P ≤ 0.001, posterior wall index (0.659 ± 0.235 vs. 0.437 ± 0.214 cm, P ≤ 0.01, and larger LVEDD index is (3.99 ± 0.48 vs. 2.170 ± 0.57 mm. P = 0.035. Pulsed Doppler showed high LV trans-mitral E wave velocity (70.818 ± 10.139 vs. 57.532 ± 10.139, p = 0.027 and E/A ratio (1.54 vs. 1.23, P ≤ 0.01. The duration of Deceleration time (DT and isovolumic relaxation time (IVRT were significantly shorter in patients with β-TM (150.234 ± 20.0.23 vs. 167.123 ± 19.143 msec, P ≤ 0.01 and (60.647 ± 6.77 vs. 75.474 ± 5.83 msec, P ≤ 0.001, respectively. The ratio of transmitral E wave velocity to the tissue Doppler E wave at the basal septal mitral annulus E/Em – was significantly higher in β-TM group (14.024 ± 2.29 vs. 12.132 ± 1.82, P ≤ 0.01. The Tissue Doppler systolic velocity (Sm and the early diastolic velocity (Em were significantly lower in β-TM group compared to control (4.31 ± 1.2 cm/s vs. 6.95 ± 2.1, P ≤ 0.01 and 4.31 ± 2.7 cm/s vs. 5.82 ± 2.5, P ≤ 0.01 respectively. The tricuspid valve velocity was significantly higher than controls (2.993 ± 0.569 vs. 1.93 ± 0.471 m/sec, respectively, P ≤ 0

Continuous-wave optically pumped green perovskite vertical-cavity surface-emitter

KAUST Repository

Alias, Mohd Sharizal; Liu, Zhixiong; Alatawi, Abdullah; Ng, Tien Khee; Wu, Tao; Ooi, Boon S.

2017-01-01

We report an optically pumped green perovskite vertical-cavity surface-emitter operating in continuous-wave (CW) with a power density threshold of ~89 kW/cm2. The device has an active region of CH3NH3PbBr3 embedded in a dielectric microcavity

Improved Micro Rain Radar snow measurements using Doppler spectra post-processing

Directory of Open Access Journals (Sweden)

M. Maahn

2012-11-01

Full Text Available The Micro Rain Radar 2 (MRR is a compact Frequency Modulated Continuous Wave (FMCW system that operates at 24 GHz. The MRR is a low-cost, portable radar system that requires minimum supervision in the field. As such, the MRR is a frequently used radar system for conducting precipitation research. Current MRR drawbacks are the lack of a sophisticated post-processing algorithm to improve its sensitivity (currently at +3 dBz, spurious artefacts concerning radar receiver noise and the lack of high quality Doppler radar moments. Here we propose an improved processing method which is especially suited for snow observations and provides reliable values of effective reflectivity, Doppler velocity and spectral width. The proposed method is freely available on the web and features a noise removal based on recognition of the most significant peak. A dynamic dealiasing routine allows observations even if the Nyquist velocity range is exceeded. Collocated observations over 115 days of a MRR and a pulsed 35.2 GHz MIRA35 cloud radar show a very high agreement for the proposed method for snow, if reflectivities are larger than −5 dBz. The overall sensitivity is increased to −14 and −8 dBz, depending on range. The proposed method exploits the full potential of MRR's hardware and substantially enhances the use of Micro Rain Radar for studies of solid precipitation.

Influence of immune-mediated hemolytic anemia on flow velocities in the portal vein and caudal vena cava measured by use of pulsed-wave Doppler ultrasonography in dogs.

Science.gov (United States)

Smith, Rachel Policelli; Koenigshof, Amy M; Smith, Daniel J; Strom, Phillip R; Nelson, Nathan C

2018-05-01

OBJECTIVE To compare blood flow velocities of the portal vein (PV) and caudal vena cava (CVC) measured by use of pulsed-wave Doppler ultrasonography in clinically normal dogs and dogs with primary immune-mediated hemolytic anemia (IMHA). ANIMALS 11 client-owned dogs admitted to a veterinary teaching hospital for management of primary IMHA and 21 staff- or student-owned clinically normal dogs. PROCEDURES Flow velocities in the PV and CVC at the porta hepatis were evaluated in conscious unsedated dogs with concurrent ECG monitoring; evaluations were performed before dogs with IMHA received heparin or blood transfusions. Three measurements of peak velocity at end expiration were obtained for each vessel, and the mean was calculated. Results were compared between IMHA and control groups. RESULTS Mean ± SD blood flow velocity in the CVC differed between control (63.0 ± 18.6 cm/s) and IMHA (104 ± 36.9 cm/s) groups. Variance in dogs with IMHA was significantly greater than that for the clinically normal dogs. No significant difference in blood flow velocity in the PV was detected between IMHA and control dogs. CONCLUSIONS AND CLINICAL RELEVANCE Higher blood flow velocities were detected by use of pulsed-wave Doppler ultrasonography in the CVC of dogs with naturally occurring IMHA and may be used to predict anemia in patients suspected of having IMHA.

Narrowing of the middle cerebral artery: artificial intelligence methods and comparison of transcranial color coded duplex sonography with conventional TCD.

Science.gov (United States)

Swiercz, Miroslaw; Swiat, Maciej; Pawlak, Mikolaj; Weigele, John; Tarasewicz, Roman; Sobolewski, Andrzej; Hurst, Robert W; Mariak, Zenon D; Melhem, Elias R; Krejza, Jaroslaw

2010-01-01

The goal of the study was to compare performances of transcranial color-coded duplex sonography (TCCS) and transcranial Doppler sonography (TCD) in the diagnosis of the middle cerebral artery (MCA) narrowing in the same population of patients using statistical and nonstatistical intelligent models for data analysis. We prospectively collected data from 179 consecutive routine digital subtraction angiography (DSA) procedures performed in 111 patients (mean age 54.17+/-14.4 years; 59 women, 52 men) who underwent TCD and TCCS examinations simultaneously. Each patient was examined independently using both ultrasound techniques, 267 M1 segments of MCA were assessed and narrowings were classified as 50% lumen reduction. Diagnostic performance was estimated by two statistical and two artificial neural networks (ANN) classification methods. Separate models were constructed for the TCD and TCCS sonographic data, as well as for detection of "any narrowing" and "severe narrowing" of the MCA. Input for each classifier consisted of the peak-systolic, mean and end-diastolic velocities measured with each sonographic method; the output was MCA narrowing. Arterial narrowings less or equal 50% of lumen reduction were found in 55 and >50% narrowings in 26 out of 267 arteries, as indicated by DSA. In the category of "any narrowing" the rate of correct assignment by all models was 82% to 83% for TCCS and 79% to 81% for TCD. In the diagnosis of >50% narrowing the overall classification accuracy remained in the range of 89% to 90% for TCCS data and 90% to 91% for TCD data. For the diagnosis of any narrowing, the sensitivity of the TCCS was significantly higher than that of the TCD, while for diagnosis of >50% MCA narrowing, sensitivity of the TCCS was similar to sensitivity of the TCD. Our study showed that TCCS outperforms conventional TCD in detection of diagnosis of >50% MCA narrowing. (E-mail: jaroslaw.krejza@uphs.upenn.edu).

Endosonographic and color doppler flow imaging alterations observed within irradiated rectal cancer

International Nuclear Information System (INIS)

Alexander, Archie A.; Palazzo, Juan P.; Ahmad, Neelofur R.; Liu, J.-B.; Forsberg, Flemming; Marks, John

1996-01-01

Purpose: To correlate the endosonographic and color Doppler flow imaging alterations observed in irradiated rectal cancers with the pathologic features of radiation response, and to evaluate the potential impact of altered blood flow on the integrity of the surgical anastamosis. Methods and Materials: Endosonography with color and pulsed wave Doppler was performed on 20 rectal cancer masses before and after high dose preoperative radiation (XRT). Pre- and post-XRT observations included comparing alterations in tumor size, sonographic echotexture, color Doppler flow, and pulsatility indices. Comparisons were made with pathologic findings in the irradiated specimens and with the incidence of anastomotic failure. Results: Compared to pre-XRT observations, irradiated rectal cancers decreased in size and became either mixed in echogenicity with less apparent color Doppler flow (16 of 20) or unchanged in color Doppler flow and echotexture (4 of 20). Those with less flow (16 of 20) were imaged later (mean = 90.2 ± 12.1 days) than those without change in color Doppler flow (mean = 21.7 ± 2.7 days). Pathologically, the group of four without change in color Doppler signal had features of acute inflammation which were not observed in 16 of 20 imaged later. Based on pulsatility index measurements, both high and low resistance vessels were detected and confirmed by immunohistochemical staining, and features of postradiation obliterative vasculitis were observed. Only one primary anastomosis in 14 patients with decreased flow failed. Conclusions: The sonographic and color Doppler flow imaging alterations observed within irradiated rectal cancer correlated with changes of postradiation obliterative vasculitis. The apparent diminished local blood flow within high and low resistance vessels post-XRT did not result in an increased incidence of anastomotic failures

Open-access transvaginal sonography in women of reproductive age with abnormal vaginal bleeding: a descriptive study in general practice

NARCIS (Netherlands)

de Vries, Corlien J. H.; Wieringa-de Waard, Margreet; Bindels, Patrick J. E.; Ankum, Willem M.

2011-01-01

Diagnostic ultrasonography is used by GPs in approximately 10% of patients of reproductive age with abnormal vaginal bleeding. Transvaginal sonography is recommended as a first-line diagnostic instrument for assessing uterine pathology. To assess if findings resulting from open-access sonography

Minimally destructive, Doppler measurement of a quantized flow in a ring-shaped Bose-Einstein condensate

Science.gov (United States)

Kumar, A.; Anderson, N.; Phillips, W. D.; Eckel, S.; Campbell, G. K.; Stringari, S.

2016-02-01

The Doppler effect, the shift in the frequency of sound due to motion, is present in both classical gases and quantum superfluids. Here, we perform an in situ, minimally destructive measurement, of the persistent current in a ring-shaped, superfluid Bose-Einstein condensate using the Doppler effect. Phonon modes generated in this condensate have their frequencies Doppler shifted by a persistent current. This frequency shift will cause a standing-wave phonon mode to be ‘dragged’ along with the persistent current. By measuring this precession, one can extract the background flow velocity. This technique will find utility in experiments where the winding number is important, such as in emerging ‘atomtronic’ devices.

Continuous-wave room-temperature diamond maser

Science.gov (United States)

Breeze, Jonathan D.; Salvadori, Enrico; Sathian, Juna; Alford, Neil Mcn.; Kay, Christopher W. M.

2018-03-01

The maser—the microwave progenitor of the optical laser—has been confined to relative obscurity owing to its reliance on cryogenic refrigeration and high-vacuum systems. Despite this, it has found application in deep-space communications and radio astronomy owing to its unparalleled performance as a low-noise amplifier and oscillator. The recent demonstration of a room-temperature solid-state maser that utilizes polarized electron populations within the triplet states of photo-excited pentacene molecules in a p-terphenyl host paves the way for a new class of maser. However, p-terphenyl has poor thermal and mechanical properties, and the decay rates of the triplet sublevel of pentacene mean that only pulsed maser operation has been observed in this system. Alternative materials are therefore required to achieve continuous emission: inorganic materials that contain spin defects, such as diamond and silicon carbide, have been proposed. Here we report a continuous-wave room-temperature maser oscillator using optically pumped nitrogen–vacancy defect centres in diamond. This demonstration highlights the potential of room-temperature solid-state masers for use in a new generation of microwave devices that could find application in medicine, security, sensing and quantum technologies.

A prospective study of levetiracetam efficacy in epileptic syndromes with continuous spikes-waves during slow sleep

DEFF Research Database (Denmark)

Atkins, Mary; Nikanorova, Marina

2011-01-01

To evaluate the add-on effect of levetiracetam (LEV) treatment on the EEG and clinical status of children with continuous spikes-waves during slow sleep (CSWS).......To evaluate the add-on effect of levetiracetam (LEV) treatment on the EEG and clinical status of children with continuous spikes-waves during slow sleep (CSWS)....

Evaluation of the renal resistive index and pulsatility index in patients with pleural effusion by duplex Doppler ultrasonography.

Science.gov (United States)

Değirmenci, Nevbahar Akcar; Metintaş, Muzaffer; Atlanoglu, Sahinde; Yıldırım, Huseyin

2013-01-01

The aim of the study was to evaluate the renal resistive index (RI) and pulsatility index (PI) in patients with pleural effusion (PE). We studied the mean renal RI and PI in 50 patients with PE and 30 healthy volunteers by Doppler sonography. We grouped effusion as unilateral and bilateral. Statistical analysis was done by independent t test and correlation coefficient analysis. The mean RI/PI in healthy volunteers and in PE patients was 0.58/0.93 and 0.72/1.35, respectively. We observed a significantly higher RI and PI in patients when compared with healthy volunteers (all p effusion (0.74 or 1.55, respectively) (p > 0.05). Pleural effusion might result in increased renal impedance as seen in cirrhosis, which is a rather complicated pathophysiological process, without causing any morphological changes in kidneys.

Second-order interference of two independent and tunable single-mode continuous-wave lasers

International Nuclear Information System (INIS)

Liu Jianbin; Chen Hui; Zheng Huaibin; Xu Zhuo; Wei Dong; Zhou Yu; Gao Hong; Li Fu-Li

2016-01-01

The second-order temporal interference of two independent single-mode continuous-wave lasers is discussed by employing two-photon interference in Feynman’s path integral theory. It is concluded that whether the second-order temporal interference pattern can or cannot be retrieved via two-photon coincidence counting rate is dependent on the resolution time of the detection system and the frequency difference between these two lasers. Two identical and tunable single-mode continuous-wave diode lasers are employed to verify the predictions. These studies are helpful to understand the physics of two-photon interference with photons of different spectra. (paper)

Contributions of scintigraphy and sonography to the diagnosis of traumatic splenic lesions in children

International Nuclear Information System (INIS)

Soucy, J.P.; Danais, S.; Filiatrault, D.; Lamoureux, J.; Lamoureux, F.

1984-01-01

20 children who were sent to the Nuclear Medicine and Sonography services for evaluation of the spleen in the context of a history of abdominal trauma were studied. All but one of the children were treated conservately, the exception having had on emergency renal procedure performed for renal rupture. The working diagnosis, based on the clinical that of splenic trauma in all cases. The result show a sensitivity of 90% (2 false negatives) for scintigraphy, and of 30% (14 false negatives) for sonography for the non-invasive diagnosis of splenic trauma in children [fr

Contributions of scintigraphy and sonography to the diagnosis of traumatic splenic lesions in children

Energy Technology Data Exchange (ETDEWEB)

Soucy, J.P.; Danais, S.; Filiatrault, D.; Lamoureux, J.; Lamoureux, F. (Hopital Sainte-Justine, Montreal (Canada))

1984-01-01

20 children who were sent to the Nuclear Medicine and Sonography services for evaluation of the spleen in the context of a history of abdominal trauma were studied. All but one of the children were treated conservately, the exception having had on emergency renal procedure performed for renal rupture. The working diagnosis, based on the clinical, was that of splenic trauma in all cases. The results show a sensitivity of 90% (2 false negatives) for scintigraphy, and of 30% (14 false negatives) for sonography for the non-invasive diagnosis of splenic trauma in children.

Top ten pitfalls to avoid when performing musculoskeletal sonography: What you should know before entering the examination room

International Nuclear Information System (INIS)

Arend, Carlos Frederico

2013-01-01

Sonography has been used successfully to evaluate a number of musculoskeletal disorders. The method is operator dependent and familiarity with sonographic pitfalls greatly improves diagnostic accuracy and helps to optimize management. In this article, we discuss ten common pitfalls which can become a source of confusion and misdiagnosis in musculoskeletal sonography

Sonography of the neonatal spine: part 1, Normal anatomy, imaging pitfalls, and variations that may simulate disorders.

Science.gov (United States)

Lowe, Lisa H; Johanek, Andrew J; Moore, Charlotte W

2007-03-01

Our objective is to discuss neonatal spine sonography with emphasis on imaging pitfalls and normal variants that may simulate disease and to distinguish them from true spinal disorders. Sonography of the neonatal spine is now accepted as a highly sensitive, readily available screening study that can be used to evaluate various anomalies of the lumbar spine in most infants younger than 4 months.

The Significance of Brain Transcranial Sonography in Burning Mouth Syndrome: a Pilot Study

Directory of Open Access Journals (Sweden)

Iris Zavoreo

2017-01-01

Full Text Available Objective: Burning mouth syndrome (BMS is a chronic disorder which is affecting mostly postmenopausal women and is characterized by burning symptoms in the oral cavity on the clinically healthy oral mucosa. The results of previous studies suggested a possible role of peripheral and/or central neurological disturbances in these patients. The aim of this study was to analyze patients with burning mouth syndrome using transcranial sonography. Methods: By use of transcranial sonography of the brain parenchyma, substantia nigra, midbrain raphe and brain nucleus were evaluated in 20 patients with BMS (64.7±12.3 years and 20 controls with chronic pain in the lumbosacral region (61.5±15. Statistical analysis was performed by use of Student t test with significance set at p<0.05. Results: The results of this study have shown hypoechogenicity of the substantia nigra and midbrain raphe as well as hyperechogenicity of the brain nucleus in BMS patients (p<0,05 as compared to controls. Conclusions: Altered transcranial sonography findings of the brain parenchyma, midbrain raphe and brain nucleus in patients with burning mouth syndrome might reflect central disturbances within this syndrome.

Real-time sonography in obstetrics.

Science.gov (United States)

Anderson, S G

1978-03-01

Three hundred fifty real-time scans were performed on pregnant women for various indications. Placental localization was satisfactorily obtained in 173 of 174 studies. Estimates of fetal gestation from directly measured biparietal diameter were +/-2 weeks of actual gestation in 153 of 172 (88.9%) measurements. The presence or absence of fetal motion and cardiac activity established a diagnosis of fetal viability or fetal death in 32 patients after the first trimester. Accurate diagnosis was made in 52 of 57 patients with threatened abortions, and two of these errors occurred in scans performed before completion of the eighth postmenstrual week. Because of the ability to demonstrate fetal motion, real-time sonography should have many applications in obstetrics.

Wave plus current over a ripple-covered bed

DEFF Research Database (Denmark)

Fredsøe, Jørgen; Andersen, Ken Haste; Sumer, B. Mutlu

1999-01-01

This paper concerns the combined wave and current boundary layer flow over a ripple-covered bed, The study comprises experiments as well as a numerical modelling study: the experimental part comprises laser Doppler anemometry (LDA) velocity and turbulence measurements, and a flow-visualization st......This paper concerns the combined wave and current boundary layer flow over a ripple-covered bed, The study comprises experiments as well as a numerical modelling study: the experimental part comprises laser Doppler anemometry (LDA) velocity and turbulence measurements, and a flow......-visualization study in the laboratory with ripples, 22 cm in length, and 3.5 cm in height. One wave-alone, three current-alone, and three combined waves and current tests were conducted. The wave-velocity-to-current-velocity ratio ranges from 1 to 2.4. The orbiral-amplitude-ro-ripple-length ratio (at the bed) is 0.......41. The effect of superimposing waves on a current is to displace the velocity profile to higher elevations. The velocity profiles exhibit two "logarithmic layers", one associated with the actual roughness of the bed (the actual ripple roughness), and the other with the apparent roughness induced by the waves...

Comparison the percentage of detection of periarthritis in patients with rheumatoid arthritis using clinical examination or ultrasound methods.

Science.gov (United States)

Karimzadeh, Hadi; Seyedbonakdar, Zahra; Mousavi, Maryam; Karami, Mehdi

2016-01-01

This study aimed to compare the percentage of detection of periarthritis in patients with rheumatoid arthritis using clinical examination and ultrasound methods. This study is a cross-sectional study which was conducted in Al-Zahra Hospital (Isfahan, Iran) during 2014-2015. In our study, ninety patients were selected based on the American College of Rheumatology 2010 criteria. All patients were examined by a rheumatologist to find the existence of effusion, and the data were filled in the checklist. The ultrasonography for detecting effusion in periarticular structures was done by an expert radiologist with two methods, including high-resolution ultrasonography and power Doppler. The percentage of effusion existence found by physical examination was compared by sonography, and the Chi-square and t -tests were used for data analysis. The percentage of effusion found in areas with physical examination by rheumatologist was lower than the frequency distribution of effusions found by sonography (8.3% VS 14.2%) ( P tendinitis (10 cases), wrist tendonitis (13 cases), olecranon bursitis (9 cases), golfers elbow (4 cases), tennis elbow (4 cases), trochanteric bursitis (6 cases), anserine bursitis (6 cases), prepatellar bursitis (11 cases), and ankle tendonitis (7 cases). Tenderness on physical examination was found in 15% of the cases, and the evidence of periarthritis was found in 21/7% through sonography ( P < 0.001) and 34% through Doppler sonography ( P < 0.001). The percentage of periarthritis detection by ultrasonography and power Doppler sonography was higher than clinical examination. Hence, the ultrasonography is more accurate than physical examination.

Determining the near-surface current profile from measurements of the wave dispersion relation

Science.gov (United States)

Smeltzer, Benjamin; Maxwell, Peter; Aesøy, Eirik; Ellingsen, Simen

2017-11-01

The current-induced Doppler shifts of waves can yield information about the background mean flow, providing an attractive method of inferring the current profile in the upper layer of the ocean. We present measurements of waves propagating on shear currents in a laboratory water channel, as well as theoretical investigations of inversion techniques for determining the vertical current structure. Spatial and temporal measurements of the free surface profile obtained using a synthetic Schlieren method are analyzed to determine the wave dispersion relation and Doppler shifts as a function of wavelength. The vertical current profile can then be inferred from the Doppler shifts using an inversion algorithm. Most existing algorithms rely on a priori assumptions of the shape of the current profile, and developing a method that uses less stringent assumptions is a focus of this study, allowing for measurement of more general current profiles. The accuracy of current inversion algorithms are evaluated by comparison to measurements of the mean flow profile from particle image velocimetry (PIV), and a discussion of the sensitivity to errors in the Doppler shifts is presented.

Clinical application of a modern high-definition head-mounted display in sonography.

Science.gov (United States)

Takeshita, Hideki; Kihara, Kazunori; Yoshida, Soichiro; Higuchi, Saori; Ito, Masaya; Nakanishi, Yasukazu; Kijima, Toshiki; Ishioka, Junichiro; Matsuoka, Yoh; Numao, Noboru; Saito, Kazutaka; Fujii, Yasuhisa

2014-08-01

Because of the remarkably improved image quality and wearability of modern head-mounted displays, a monitoring system using a head-mounted display rather than a fixed-site monitor for sonographic scanning has the potential to improve the diagnostic performance and lessen the examiner's physical burden during a sonographic examination. In a preclinical setting, 2 head-mounted displays, the HMZ-T2 (Sony Corporation, Tokyo, Japan) and the Wrap1200 (Vuzix Corporation, Rochester, NY), were found to be applicable to sonography. In a clinical setting, the feasibility of the HMZ-T2 was shown by its good image quality and acceptable wearability. This modern device is appropriate for clinical use in sonography. © 2014 by the American Institute of Ultrasound in Medicine.

Generation of ultrasound in materials using continuous-wave lasers.

Science.gov (United States)

Caron, James N; DiComo, Gregory P; Nikitin, Sergei

2012-03-01

Generating and detecting ultrasound is a standard method of nondestructive evaluation of materials. Pulsed lasers are used to generate ultrasound remotely in situations that prohibit the use of contact transducers. The scanning rate is limited by the repetition rates of the pulsed lasers, ranging between 10 and 100 Hz for lasers with sufficient pulse widths and energies. Alternately, a high-power continuous-wave laser can be scanned across the surface, creating an ultrasonic wavefront. Since generation is continuous, the scanning rate can be as much as 4 orders of magnitude higher than with pulsed lasers. This paper introduces the concept, comparing the theoretical scanning speed with generation by pulsed laser. © 2012 Optical Society of America

Commissioning status of the Continuous Wave Deuterium Demonstrator

International Nuclear Information System (INIS)

Hartog, P.D.; Dooling, J.; Lorello, M.; Rathke, J.; Carwardine, J.; Godden, D.; Pile, G.; Yule, T.; Zinneman, T.

1993-01-01

Grumman Aerospace Corporation, Argonne National Laboratory, and Culham Laboratory are commissioning the Continuous Wave Deuterium Demonstrator (CWDD) in a facility at Argonne National Laboratory. CWDD is a high-brightness, high-current, 7.5-MeV negative deuterium accelerator. The 352-MHz rf accelerating cavities are cryogenically cooled with supercritical neon to reduce the rf power requirements. Installation of the accelerator into the Argonne facility began in May 1991, and first beam from the injector was extracted in February 1992. The accelerator and facility and described, and current status and future plans are discussed

Gravitational-wave bursts from the nuclei of distant galaxies and quasars: proposal for detection using Doppler tracking of interplanetary spacecraft

International Nuclear Information System (INIS)

Thorne, K.S.; Braginsky, V.B.

1976-01-01

It is likely that supermassive black holes (Mapprox. =10 6 to 10 10 M/sub sun/) exist in the nuclei of many quasars and galaxies. The collapse which forms these holes and subsequent collisions between them should produce strong, broad-band bursts of gravitational waves: for a source of mass M at the Hubble distance of approx.10 10 light-years, the dimensionless amplitude would be h approx. 2 x 10 -17 x (M/10 6 M/sub sun/), and the duration of the burst would be tauapprox. (90 s) x (M/10 6 M/sub sun/). Such bursts might arrive at Earth as often as 50 times per year: or as rarely as once each 300 years. The detection of such bursts may be possible within the next few years using dual-frequency Doppler tracking of interplanetary spacecraft

Application of scanning laser Doppler vibrometry for delamination detection in composite structures

Science.gov (United States)

Kudela, Pawel; Wandowski, Tomasz; Malinowski, Pawel; Ostachowicz, Wieslaw

2017-12-01

In this paper application of scanning laser Doppler vibrometry for delamination detection in composite structures was presented. Delamination detection was based on a guided wave propagation method. In this papers results from numerical and experimental research were presented. In the case of numerical research, the Spectral Element Method (SEM) was utilized, in which a mesh was composed of 3D spectral elements. SEM model included also a piezoelectric transducer. In the experimental research guided waves were excited using the piezoelectric transducer whereas the sensing process was conducted using scanning laser Doppler vibrometer (SLDV). Analysis of guided wave propagation and its interaction with delamination was based on a full wavefield approach. Attention was focused on interactions of guided waves with delamination manifested by A0 mode reflection, A0 mode entrapment, and S0/A0 mode conversion. Delamination was simulated by a teflon insert located between plies of composite material. Results of interaction with symmetrically and nonsymmetrical placed delamination (in respect to the composite sample thickness) were presented. Moreover, the authors investigated different size of delaminations. Damage detection was based on a new signal processing algorithm proposed by the authors. In this approach the weighted RMS was utilized selectively. It means that the summation in RMS formula was performed only for a specially selected time instances. Results for simple composite panels, panel with honeycomb core, and real stiffened composite panel from the aircraft were presented.

Using modern teaching strategies to teach upper abdominal sonography to medical students

Directory of Open Access Journals (Sweden)

Wei-Chun Cheng

2013-07-01

Conclusion: We have greatly simplified the process of learning about upper abdominal sonography by using andragogy to enhance learning, mnemonics to help memory, and a pin-badge reward system to stimulate incentives.

Spin-wave propagation and spin-polarized electron transport in single-crystal iron films

Science.gov (United States)

Gladii, O.; Halley, D.; Henry, Y.; Bailleul, M.

2017-11-01

The techniques of propagating spin-wave spectroscopy and current-induced spin-wave Doppler shift are applied to a 20-nm-thick Fe/MgO(001) film. The magnetic parameters extracted from the position of the spin-wave resonance peaks are very close to those tabulated for bulk iron. From the zero-current propagating wave forms, a group velocity of 4 km/s and an attenuation length of about 6 μ m are extracted for 1.6-μ m -wavelength spin wave at 18 GHz. From the measured current-induced spin-wave Doppler shift, we extract a surprisingly high degree of spin polarization of the current of 83 % , which constitutes the main finding of this work. This set of results makes single-crystalline iron a promising candidate for building devices utilizing high-frequency spin waves and spin-polarized currents.

Optimization of Region of Interest Drawing for Quantitative Analysis: Differentiation Between Benign and Malignant Breast Lesions on Contrast-Enhanced Sonography.

Science.gov (United States)

Nakata, Norio; Ohta, Tomoyuki; Nishioka, Makiko; Takeyama, Hiroshi; Toriumi, Yasuo; Kato, Kumiko; Nogi, Hiroko; Kamio, Makiko; Fukuda, Kunihiko

2015-11-01

This study was performed to evaluate the diagnostic utility of quantitative analysis of benign and malignant breast lesions using contrast-enhanced sonography. Contrast-enhanced sonography using the perflubutane-based contrast agent Sonazoid (Daiichi Sankyo, Tokyo, Japan) was performed in 94 pathologically proven palpable breast mass lesions, which could be depicted with B-mode sonography. Quantitative analyses using the time-intensity curve on contrast-enhanced sonography were performed in 5 region of interest (ROI) types (manually traced ROI and circular ROIs of 5, 10, 15, and 20 mm in diameter). The peak signal intensity, initial slope, time to peak, positive enhancement integral, and wash-out ratio were investigated in each ROI. There were significant differences between benign and malignant lesions in the time to peak (P benign and malignant lesions in the time to peak (P benign and malignant breast lesions. © 2015 by the American Institute of Ultrasound in Medicine.

Comparison of computerized tomography to sonography, applied in diseases of the pancreas

International Nuclear Information System (INIS)

Kluge, K.

1982-01-01

The examination results of 418 patients whose epigastria had been examined both by computerized tomography and sonography over 1 week in the time from beginning January 1978 until and of July 1979 were compared with regard to the imaging of the pancreas, reliability, and the specificity and sensitivity in establishing the diagnosis. For the sonographic examination, a compound and a real-time unit were used; the computerized tomography was carried out by means of an equipment of the 3rd generation with a scan time of 4 sec. The screening of the pancreas was significantly better using computerized tomography (99.3% US. 84% with US). As for accuracy, computerized tomography had 92.5% exact diagnoses versus 79.9% obtained by sonography. If, however, we look at the cases in which the pancreas could be screened with both methods the accuracy was almost the same (93.7 CT and 93.3% US). Specificity was almost of the same quality, however, the method of computerized tomography with 0.963 was slightly better than ultrasound with 0.943. As for sensitivity, sonography with 0.838 was better than CT with 0.721. The reason for that is the fact that a big part of the chronic pancreatites (30.3%) were not recognized by means of computerized tomography. (orig.) [de

Duplex sonography in the planning and evaluation of arteriovenous fistulae for haemodialysis

International Nuclear Information System (INIS)

Kerr, S.F.; Krishan, S.; Lapham, R.C.; Weston, M.J.

2010-01-01

This paper describes how to perform duplex sonography in the planning and evaluation of arteriovenous fistulae in haemodialysis patients, discusses its roles in these settings, and presents a review of commonly encountered complications.

Ultralow power continuous-wave frequency conversion in hydrogenated amorphous silicon waveguides.

Science.gov (United States)

Wang, Ke-Yao; Foster, Amy C

2012-04-15

We demonstrate wavelength conversion through nonlinear parametric processes in hydrogenated amorphous silicon (a-Si:H) with maximum conversion efficiency of -13 dB at telecommunication data rates (10 GHz) using only 15 mW of pump peak power. Conversion bandwidths as large as 150 nm (20 THz) are measured in continuous-wave regime at telecommunication wavelengths. The nonlinear refractive index of the material is determined by four-wave mixing (FWM) to be n(2)=7.43×10(-13) cm(2)/W, approximately an order of magnitude larger than that of single crystal silicon. © 2012 Optical Society of America

Role of focused assessment with sonography for trauma as a ...

African Journals Online (AJOL)

Background: The objective of the study was to review the utility of focused assessement with sonography for trauma (FAST) as a screening tool for blunt abdominal trauma (BAT) in children involved in high energy trauma (HET), and to determine whether a FAST could replace computed tomography (CT) in clinical ...

Continuous-wave Optically Pumped Lasing of Hybrid Perovskite VCSEL at Green Wavelength

KAUST Repository

Alias, Mohd Sharizal

2017-05-08

We demonstrate the lasing of a perovskite vertical-cavity surface-emitting laser at green wavelengths, which operates under continuous-wave optical pumping at room-temperature by embedding hybrid perovskite between dielectric mirrors deposited at low-temperature.

Continuous-wave Optically Pumped Lasing of Hybrid Perovskite VCSEL at Green Wavelength

KAUST Repository

Alias, Mohd Sharizal; Liu, Zhixiong; Alatawi, Abdullah; Ng, Tien Khee; Wu, Tao; Ooi, Boon S.

2017-01-01

We demonstrate the lasing of a perovskite vertical-cavity surface-emitting laser at green wavelengths, which operates under continuous-wave optical pumping at room-temperature by embedding hybrid perovskite between dielectric mirrors deposited at low-temperature.

Fresh look at the doppler changes in pregnancies with placental-based complications

Directory of Open Access Journals (Sweden)

S Dikshit

2011-01-01

Full Text Available Placental-based complications of pregnancy can be classified as acute and chronic. An example of acute placental complication is abruptio placenta. The chronic placental complications include pregnancy induced hypertension (PIH and idiopathic Intrauterine growth restriction (IUGR. The fetus is at risk for perinatal complications in both acute and chronic conditions. Here we take a look at the natural history of the Doppler parameters in chronic conditions. The techniques used for assessing the fetal well-being include, clinical methods, biophysical tests, conventional ultrasonography, and fetal Doppler studies. Arterial Doppler studies are used to assess the well-being of the fetus and to determine the timing of delivery. However, arterial Dopplers predict only the subset of fetuses at risk of having perinatal complications. Venous Dopplers have been used to improve upon the prognostication. However, by the time the commonly used venous Doppler signs, that is, ′A′ wave reversal in ductus venosus (DV is present, the fetus is likely to be already compromised. The fetus tries to adapt to the environment of deprivation by making a series of changes in the umbilical artery circulation, cerebral circulation, and hepatic circulation. As a result of these adaptations, the fetus overcomes the state of chronic hypoxia. This article takes a look at these changes and also the effect of these adaptations. It is suggested that serial comparisons of the venous flow characteristics of the DV and inferior vena cava (IVC can provide an early indication of the impending decompensation and can be used to predict the time the delivery.

High PRF ultrafast sliding compound doppler imaging: fully qualitative and quantitative analysis of blood flow

Science.gov (United States)

Kang, Jinbum; Jang, Won Seuk; Yoo, Yangmo

2018-02-01

Ultrafast compound Doppler imaging based on plane-wave excitation (UCDI) can be used to evaluate cardiovascular diseases using high frame rates. In particular, it provides a fully quantifiable flow analysis over a large region of interest with high spatio-temporal resolution. However, the pulse-repetition frequency (PRF) in the UCDI method is limited for high-velocity flow imaging since it has a tradeoff between the number of plane-wave angles (N) and acquisition time. In this paper, we present high PRF ultrafast sliding compound Doppler imaging method (HUSDI) to improve quantitative flow analysis. With the HUSDI method, full scanline images (i.e. each tilted plane wave data) in a Doppler frame buffer are consecutively summed using a sliding window to create high-quality ensemble data so that there is no reduction in frame rate and flow sensitivity. In addition, by updating a new compounding set with a certain time difference (i.e. sliding window step size or L), the HUSDI method allows various Doppler PRFs with the same acquisition data to enable a fully qualitative, retrospective flow assessment. To evaluate the performance of the proposed HUSDI method, simulation, in vitro and in vivo studies were conducted under diverse flow circumstances. In the simulation and in vitro studies, the HUSDI method showed improved hemodynamic representations without reducing either temporal resolution or sensitivity compared to the UCDI method. For the quantitative analysis, the root mean squared velocity error (RMSVE) was measured using 9 angles (-12° to 12°) with L of 1-9, and the results were found to be comparable to those of the UCDI method (L  =  N  =  9), i.e.  ⩽0.24 cm s-1, for all L values. For the in vivo study, the flow data acquired from a full cardiac cycle of the femoral vessels of a healthy volunteer were analyzed using a PW spectrogram, and arterial and venous flows were successfully assessed with high Doppler PRF (e.g. 5 kHz at L�

High PRF ultrafast sliding compound doppler imaging: fully qualitative and quantitative analysis of blood flow.

Science.gov (United States)

Kang, Jinbum; Jang, Won Seuk; Yoo, Yangmo

2018-02-09

Ultrafast compound Doppler imaging based on plane-wave excitation (UCDI) can be used to evaluate cardiovascular diseases using high frame rates. In particular, it provides a fully quantifiable flow analysis over a large region of interest with high spatio-temporal resolution. However, the pulse-repetition frequency (PRF) in the UCDI method is limited for high-velocity flow imaging since it has a tradeoff between the number of plane-wave angles (N) and acquisition time. In this paper, we present high PRF ultrafast sliding compound Doppler imaging method (HUSDI) to improve quantitative flow analysis. With the HUSDI method, full scanline images (i.e. each tilted plane wave data) in a Doppler frame buffer are consecutively summed using a sliding window to create high-quality ensemble data so that there is no reduction in frame rate and flow sensitivity. In addition, by updating a new compounding set with a certain time difference (i.e. sliding window step size or L), the HUSDI method allows various Doppler PRFs with the same acquisition data to enable a fully qualitative, retrospective flow assessment. To evaluate the performance of the proposed HUSDI method, simulation, in vitro and in vivo studies were conducted under diverse flow circumstances. In the simulation and in vitro studies, the HUSDI method showed improved hemodynamic representations without reducing either temporal resolution or sensitivity compared to the UCDI method. For the quantitative analysis, the root mean squared velocity error (RMSVE) was measured using 9 angles (-12° to 12°) with L of 1-9, and the results were found to be comparable to those of the UCDI method (L  =  N  =  9), i.e.  ⩽0.24 cm s -1 , for all L values. For the in vivo study, the flow data acquired from a full cardiac cycle of the femoral vessels of a healthy volunteer were analyzed using a PW spectrogram, and arterial and venous flows were successfully assessed with high Doppler PRF (e.g. 5 kHz at L�

All-optoelectronic continuous wave THz imaging for biomedical applications

International Nuclear Information System (INIS)

Siebert, Karsten J; Loeffler, Torsten; Quast, Holger; Thomson, Mark; Bauer, Tobias; Leonhardt, Rainer; Czasch, Stephanie; Roskos, Hartmut G

2002-01-01

We present an all-optoelectronic THz imaging system for ex vivo biomedical applications based on photomixing of two continuous-wave laser beams using photoconductive antennas. The application of hyperboloidal lenses is discussed. They allow for f-numbers less than 1/2 permitting better focusing and higher spatial resolution compared to off-axis paraboloidal mirrors whose f-numbers for practical reasons must be larger than 1/2. For a specific histological sample, an analysis of image noise is discussed

Treatment response assessment of radiofrequency ablation for hepatocellular carcinoma: Usefulness of virtual CT sonography with magnetic navigation

International Nuclear Information System (INIS)

Minami, Yasunori; Kitai, Satoshi; Kudo, Masatoshi

2012-01-01

Purpose: Virtual CT sonography using magnetic navigation provides cross sectional images of CT volume data corresponding to the angle of the transducer in the magnetic field in real-time. The purpose of this study was to clarify the value of this virtual CT sonography for treatment response of radiofrequency ablation for hepatocellular carcinoma. Patients and methods: Sixty-one patients with 88 HCCs measuring 0.5–1.3 cm (mean ± SD, 1.0 ± 0.3 cm) were treated by radiofrequency ablation. For early treatment response, dynamic CT was performed 1–5 days (median, 2 days). We compared early treatment response between axial CT images and multi-angle CT images using virtual CT sonography. Results: Residual tumor stains on axial CT images and multi-angle CT images were detected in 11.4% (10/88) and 13.6% (12/88) after the first session of RFA, respectively (P = 0.65). Two patients were diagnosed as showing hyperemia enhancement after the initial radiofrequency ablation on axial CT images and showed local tumor progression shortly because of unnoticed residual tumors. Only virtual CT sonography with magnetic navigation retrospectively showed the residual tumor as circular enhancement. In safety margin analysis, 10 patients were excluded because of residual tumors. The safety margin more than 5 mm by virtual CT sonographic images and transverse CT images were determined in 71.8% (56/78) and 82.1% (64/78), respectively (P = 0.13). The safety margin should be overestimated on axial CT images in 8 nodules. Conclusion: Virtual CT sonography with magnetic navigation was useful in evaluating the treatment response of radiofrequency ablation therapy for hepatocellular carcinoma.

Terminal load response law of coaxial cable to continuous wave electromagnetic irradiation

International Nuclear Information System (INIS)

Pan Xiaodong; Wei Guanghui; Li Xinfeng; Lu Xinfu

2012-01-01

In order to study the coupling response law of continuous wave electromagnetic irradiation to coaxial cable, the typical RF coaxial cable is selected as the object under test. The equipment or subsystem connected by coaxial cable is equivalent to a lumped load. Continuous wave irradiation effect experiments under different conditions are carried out to analyze the terminal load response law of coaxial cable. The results indicate that the coaxial cable has a frequency selecting characteristic under electromagnetic irradiation, and the terminal load response voltage peak appears at a series of discrete frequency points where the test cable's relative lengths equal to semi-integers. When the coaxial cable is irradiated by continuous wave, the induced sheath current converts to the differential-mode induced voltage between inner conductor and shielding layer through transfer impedance, and the internal resistance of induced voltage source is the characteristic impedance of the coaxial cable. The change in terminal load value has no influence on the response curve. The voltages on the terminal load and the internal resistance of equivalent induced voltage source obey the principle of voltage division. Moreover, when the sheath current on the coaxial cable is in resonance, the distributed induced voltage between adjacent current nodes is in the same polarity, which can be equivalent to a single induced voltage source. The induced voltage source which is adjacent to the terminal load plays the leading role in the irradiation response process. (authors)

Stochastic generation of continuous wave spectra

DEFF Research Database (Denmark)

Trulsen, J.; Dysthe, K. B.; Pécseli, Hans

1983-01-01

Wave packets of electromagnetic or Langmuir waves trapped in a well between oscillating reflectors are considered. An equation for the temporal evolution of the probability distribution for the carrier wave number is derived, and solved analytically in terms of moments in the limits of long...

Sonography, CT and MR in soft part growths in the head and neck region

International Nuclear Information System (INIS)

Brinkmann, G.; Brix, F.; Beigel, A.

1990-01-01

14 patients with a space-occupying growth in the head and neck region were examined via sonography, CT and MR to explore and demonstrate by means of a prospective comparative study the possibilities offered by these three imaging methods. Stages are best diagnosed by means of sonography; the leading role of this method is undisputed. To clarify sonographically unclear findings and especially in pre-surgery planning, MR offers advantages over CT on account of the high soft-part contrast and multiplanar visualisation. However, it is impossible or very difficult to differentiate abscesses and lymphadenitides from malignant growths with these three methods solely on the basis of image-morphological criteria. (orig.) [de

Mitral valve coaptation and its relationship to late diastolic flow: A color Doppler and vector flow map echocardiographic study in normal subjects.

Science.gov (United States)

Sherrid, Mark V; Kushner, Josef; Yang, Georgiana; Ro, Richard

2017-04-01

Three competing theories about the mechanism of mitral coaptation in normal subjects were evaluated by color Doppler and vector flow mapping (VFM): (1) beginning of ventricular (LV) ejection, (2) "breaking of the jet" of diastolic LV inflow, and (3) returning diastolic vortices impacting the leaflets on their LV surfaces. We analyzed 80 color Doppler frames and 320 VFM measurements. In all 20 normal subjects, coaptation occurred before LV ejection, 78±16 ms before onset. On color Doppler frames the larger anterior, and smaller posterior vortices circle back and, in all cases, strike the ventricular surfaces of the leaflets. On the first closing-begins frame, for the first time, vortex velocity normal to the ventricular surface of the anterior leaflet (AML) is greater than that in the mitral orifice, and the angle of attack of LV vortical flow onto the AML is twice as high as the angle of flow onto the valve in orifice. Thus, at the moment coaptation begins, vortical flow strikes the mitral leaflet with higher velocity, and higher angle of attack than orifice flow, and thus with greater force. According to the "breaking of the jet" theory, one would expect to see de novo LV flow perpendicular to the leaflets beginning after transmitral flow terminates. Instead, the returning continuous LV vortical flow that impacts the valve builds continuously after the P-wave. Late diastolic vortices strike the ventricular surfaces of the mitral leaflets and contribute to valve coaptation, permitted by concomitant decline in transmitral flow. © 2017, Wiley Periodicals, Inc.

Ultrasonography with color Doppler and power Doppler in the diagnosis of periapical lesions

International Nuclear Information System (INIS)

Goel, Sumit; Nagendrareddy, Suma Gundareddy; Raju, Manthena Srinivasa; Krishnojirao, Dayashankara Rao Jingade; Rastogi, Rajul; Mohan, Ravi Prakash Sasankoti; Gupta, Swati

2011-01-01

To evaluate the efficacy of ultrasonography (USG) with color Doppler and power Doppler applications over conventional radiography in the diagnosis of periapical lesions. 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. 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. 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

Transcranial sonography and functional imaging in glucocerebrosidase mutation Parkinson disease.

Science.gov (United States)

Barrett, M J; Hagenah, J; Dhawan, V; Peng, S; Stanley, K; Raymond, D; Deik, A; Gross, S J; Schreiber-Agus, N; Mirelman, A; Marder, K; Ozelius, L J; Eidelberg, D; Bressman, S B; Saunders-Pullman, R

2013-02-01

Heterozygous glucocerebrosidase (GBA) mutations are the leading genetic risk factor for Parkinson disease, yet imaging correlates, particularly transcranial sonography, have not been extensively described. To determine whether GBA mutation heterozygotes with Parkinson disease demonstrate hyperechogenicity of the substantia nigra, transcranial sonography was performed in Ashkenazi Jewish Parkinson disease subjects, tested for the eight most common Gaucher disease mutations and the LRRK2 G2019S mutation, and in controls. [(18)F]-fluorodeoxyglucose or [(18)F]-fluorodopa positron emission tomography is also reported from a subset of Parkinson disease subjects with heterozygous GBA mutations. Parkinson disease subjects with heterozygous GBA mutations (n = 23) had a greater median maximal area of substantia nigral echogenicity compared to controls (n = 34, aSNmax = 0.30 vs. 0.18, p = 0.007). There was no difference in median maximal area of nigral echogenicity between Parkinson disease groups defined by GBA and LRRK2 genotype: GBA heterozygotes; GBA homozygotes/compound heterozygotes (n = 4, aSNmax = 0.27); subjects without LRRK2 or GBA mutations (n = 32, aSNmax = 0.27); LRRK2 heterozygotes/homozygotes without GBA mutations (n = 27, aSNmax = 0.28); and GBA heterozygotes/LRRK2 heterozygotes (n = 4, aSNmax = 0.32, overall p = 0.63). In secondary analyses among Parkinson disease subjects with GBA mutations, maximal area of nigral echogenicity did not differ based on GBA mutation severity or mutation number. [(18)F]-fluorodeoxyglucose (n = 3) and [(18)F]-fluorodopa (n = 2) positron emission tomography in Parkinson disease subjects with heterozygous GBA mutations was consistent with findings in idiopathic Parkinson disease. Both transcranial sonography and positron emission tomography are abnormal in GBA mutation associated Parkinson disease, similar to other Parkinson disease subjects. Copyright © 2012 Elsevier Ltd. All rights reserved.

(abstract) Tropospheric Calibration for the Mars Observer Gravity Wave Experiment

Science.gov (United States)

Walter, Steven J.; Armstrong, John

1994-01-01

In spring 1993, microwave radiometer-based tropospheric calibration was provided for the Mars Observer gravitational wave search. The Doppler shifted X-band radio signals propagating between Earth and the Mars Observer satellite were precisely measured to determine path length variations that might signal passage of gravitational waves. Experimental sensitivity was restricted by competing sources of variability in signal transit time. Principally, fluctuations in the solar wind and ionospheric plasma density combined with fluctions in tropospheric refractivity determined the detection limit. Troposphere-induced path delay fluctions are dominated by refractive changes caused by water vapor inhomogeneities blowing through the signal path. Since passive microwave remote sensing techniques are able to determine atmospheric propagation delays, radiometer-based tropospheric calibration was provided at the Deep Space Network Uranus tracking site (DSS-15). Two microwave water vapor radiometers (WVRs), a microwave temperature profiler (MTP), and a ground based meterological station were deployed to determine line-of-sight vapor content and vertical temperature profile concurrently with Mars Observer tracking measurements. This calibration system provided the capability to correct Mars Observer Doppler data for troposphere-induced path variations. We present preliminary analysis of the Doppler and WVR data sets illustrating the utility of WVRs to calibrate Doppler data. This takes an important step toward realizing the ambitious system required to support future Ka-band Cassini satellite gravity wave tropospheric calibration system.

The Benefit of Sonography in Pregnancy-associated Breast Cancer

International Nuclear Information System (INIS)

Son, Eun Ju; Oh, Ki Keun; Kim, Eun Kyung

2005-01-01

To evaluate the sonographic, mammographic and MRI features of pregnancy-associated breast cancer with the major focus on the sonographic benefit in a diagnosis of pregnancy associated breast cancer. From 1998 to 2002, sonography was performed on a total 7 patients (age 23 to 38 years), who were pathologically diagnosed with breast cancer during pregnancy. Six of those patients underwent mammography. Five patients underwent a breast MRI, preoperatively. The radiological findings were evaluated retrospectively. Six patients underwent surgery and 1 patient underwent a core biopsy and chemotherapy. The histological, nuclear grading and pathological staging were evaluated. The sonographic findings showed a mass with irregular shapes (n=6), irregular margins (n=6), a non-parallel orientation (n=5), complex echo patterns (n=5). Associated findings could be observed in 3 patients, including Cooper's ligament thickening (n=2), edema (n=2), skin thickening (n=1) and axillary lymphadenopathy (n=3). The sonographic findings were positive and showed masses in 6 patients. All the patients had a dense breast in mammography. The mammographic findings included masses (n=4), masses with microcalcifications (n=2), masses with axillary lymphadenopathy (n=3), calcifications alone (n=1), an asymmetric density alone (n=1), extremely dense breasts with negative findings (n=2). A breast MRI showed an irregular shaped mass (n=4) with a rim-like enhancement (n=3), linear ductal enhancement without a mass (n= 1), and the time intensity cure revealed the typical pattern and level of enhancement in the carcinoma. Sonography is a valuable tool for diagnosing pregnancy-associated breast cancer. However, mammography should be performed if there is a suspicious lesion on sonography in order to confirm the pregnancy-associated breast cancer. Mammography has a lower sensitivity during pregnancy due to the physiologic changes in the breasts. However, calcifications and associated findings are helpful

Two-dimensional intraventricular flow mapping by digital processing conventional color-Doppler echocardiography images.

Science.gov (United States)

Garcia, Damien; Del Alamo, Juan C; Tanne, David; Yotti, Raquel; Cortina, Cristina; Bertrand, Eric; Antoranz, José Carlos; Perez-David, Esther; Rieu, Régis; Fernandez-Aviles, Francisco; Bermejo, Javier

2010-10-01

Doppler echocardiography remains the most extended clinical modality for the evaluation of left ventricular (LV) function. Current Doppler ultrasound methods, however, are limited to the representation of a single flow velocity component. We thus developed a novel technique to construct 2D time-resolved (2D+t) LV velocity fields from conventional transthoracic clinical acquisitions. Combining color-Doppler velocities with LV wall positions, the cross-beam blood velocities were calculated using the continuity equation under a planar flow assumption. To validate the algorithm, 2D Doppler flow mapping and laser particle image velocimetry (PIV) measurements were carried out in an atrio-ventricular duplicator. Phase-contrast magnetic resonance (MR) acquisitions were used to measure in vivo the error due to the 2D flow assumption and to potential scan-plane misalignment. Finally, the applicability of the Doppler technique was tested in the clinical setting. In vitro experiments demonstrated that the new method yields an accurate quantitative description of the main vortex that forms during the cardiac cycle (mean error for vortex radius, position and circulation). MR image analysis evidenced that the error due to the planar flow assumption is close to 15% and does not preclude the characterization of major vortex properties neither in the normal nor in the dilated LV. These results are yet to be confirmed by a head-to-head clinical validation study. Clinical Doppler studies showed that the method is readily applicable and that a single large anterograde vortex develops in the healthy ventricle while supplementary retrograde swirling structures may appear in the diseased heart. The proposed echocardiographic method based on the continuity equation is fast, clinically-compliant and does not require complex training. This technique will potentially enable investigators to study of additional quantitative aspects of intraventricular flow dynamics in the clinical setting by

A review of results of the international ionospheric Doppler sounder network

Czech Academy of Sciences Publication Activity Database

Laštovička, Jan; Chum, Jaroslav

2017-01-01

Roč. 60, č. 8 (2017), s. 1629-1643 ISSN 0273-1177 R&D Projects: GA ČR(CZ) GC15-07281J Institutional support: RVO:68378289 Keywords : ionospheric Doppler shift sounding * gravity waves * infrasound * solar forcing Subject RIV: DG - Athmosphere Sciences, Meteorology OBOR OECD: Meteorology and atmospheric sciences Impact factor: 1.401, year: 2016 http://www.sciencedirect.com/science/article/pii/S0273117717300790?via%3Dihub

Watt-Level Continuous-Wave Emission from a Bi-Functional Quantum Cascade Laser/Detector

Science.gov (United States)

2017-04-18

cally authorized by the U.S. Government may violate any copyrights that exist in this work. Watt-level continuous- wave emission from a bi- functional ... wave bi- functional devices, opens the perspective of on-chip dual comb spectroscopy. Also for discrete sens- ing setups, one can switch to lasers...seas.harvard.edu Abstract Bi- functional active regions, capable of light generation and detection at the same wavelength, allow a straightforward realization of

Doppler and time-travel broadening in ICR plasma isotope separation

International Nuclear Information System (INIS)

Karchevskii, A.I.; Potanin, E.P.

1994-01-01

Isotopically-selective ion-cyclotron resonance (ICR) heating is one of the most promising plasma isotope separation methods. The separation degree of ICR separation in a plasma depends on the resonance heating selectivity. The selectivity is due to the isotopically-adjacent accelerated ions resonance curve overlapping and therefore, is determined by the width of the resonance curves. In the case of a collisionless plasma in an ideal homogeneous longitudinal magnetic field, the line broadening is mainly determined by Doppler and time-travel effects. These effects differ in nature, and one has some difficulties in distinguishing them when interpreting the resonance curves because both broadenings depend on ion axial velocities. We consider the simplest case: the extrenal heating alternating electric field does not depend on the axial coordinate (the wave number γ = 0). Hence, in this case the Doppler effect does not occur

Rectal sonography before and after radiation treatment in inoperable cervical cancer

International Nuclear Information System (INIS)

Deutinger, J.; Bernaschek, G.; Tatra, G.

1989-01-01

Transrectal sonography is helpful in the classification of parametrial infiltration prior to treatment as well as in the follow-up. In this study, we performed rectal sonography in cases of inoperable cervical cancer to objectify the reduction of the infiltration of the uterine cervix and of the parametrium. Rectosonography was performed in 10 patients with histologically confirmed cancer of the uterine cervix before and after radiation treatment. The patients were treated with brachytherapy and teletherapy with an average radiation dose of 7680 rad. The whole therapy was finished after 6 to 9 weeks. Rectosonography enabled us to objectify the effect of radiation therapy. The length and width of parametrial infiltration could be measured in relation to the pelvis wall. Furthermore, the configuration of the parametrium could be imaged. Therefore, in cervical cancer, rectosonography is a valuable method to check and the documentate the effect of treatment and to diagnose recurrency. (orig.) [de

Aerosol backscatter measurements at 10.6 microns with airborne and ground-based CO2 Doppler lidars over the Colorado High Plains. I - Lidar intercomparison

Science.gov (United States)

Bowdle, David A.; Rothermel, Jeffry; Vaughan, J. Michael; Brown, Derek W.; Post, Madison J.

1991-01-01

An airborne continuous-wave (CW) focused CO2 Doppler lidar and a ground-based pulsed CO2 Doppler lidar were to obtain seven pairs of comparative measurements of tropospheric aerosol backscatter profiles at 10.6-micron wavelength, near Denver, Colorado, during a 20-day period in July 1982. In regions of uniform backscatter, the two lidars show good agreement, with differences usually less than about 50 percent near 8-km altitude and less than a factor of 2 or 3 elsewhere but with the pulsed lidar often lower than the CW lidar. Near sharp backscatter gradients, the two lidars show poorer agreement, with the pulsed lidar usually higher than the CW lidar. Most discrepancies arise from a combination of atmospheric factors and instrument factors, particularly small-scale areal and temporal backscatter heterogeneity above the planetary boundary layer, unusual large-scale vertical backscatter structure in the upper troposphere and lower stratosphere, and differences in the spatial resolution, detection threshold, and noise estimation for the two lidars.

Ultrasonography with color Doppler and power Doppler in the diagnosis of periapical lesions

Science.gov (United States)

Goel, Sumit; Nagendrareddy, Suma Gundareddy; Raju, Manthena Srinivasa; Krishnojirao, Dayashankara Rao Jingade; Rastogi, Rajul; Mohan, Ravi Prakash Sasankoti; Gupta, Swati

2011-01-01

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. PMID:22223940

Ultrasonography with color Doppler and power Doppler in the diagnosis of periapical lesions

Directory of Open Access Journals (Sweden)

Sumit Goel

2011-01-01

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.

One step linear reconstruction method for continuous wave diffuse optical tomography

Science.gov (United States)

Ukhrowiyah, N.; Yasin, M.

2017-09-01

The method one step linear reconstruction method for continuous wave diffuse optical tomography is proposed and demonstrated for polyvinyl chloride based material and breast phantom. Approximation which used in this method is selecting regulation coefficient and evaluating the difference between two states that corresponding to the data acquired without and with a change in optical properties. This method is used to recovery of optical parameters from measured boundary data of light propagation in the object. The research is demonstrated by simulation and experimental data. Numerical object is used to produce simulation data. Chloride based material and breast phantom sample is used to produce experimental data. Comparisons of results between experiment and simulation data are conducted to validate the proposed method. The results of the reconstruction image which is produced by the one step linear reconstruction method show that the image reconstruction almost same as the original object. This approach provides a means of imaging that is sensitive to changes in optical properties, which may be particularly useful for functional imaging used continuous wave diffuse optical tomography of early diagnosis of breast cancer.

[Performances and place of sonography in the diagnostic of endometriosis: CNGOF-HAS Endometriosis Guidelines].

Science.gov (United States)

Philip, C-A; Dubernard, G

2018-03-01

Endometriosis is difficult to diagnose clinically. Transvaginal sonography (TVS) is a procedure that is known to be operator-dependent, which mean that published evidences has to be balanced with the level of the sonographer that produced the data. The objective of this publication was to assess the performances of the sonography in the diagnosis of endometriosis in order to establish the French national recommendations. We searched the MEDLINE database for publication from January 2000 to September 2017 using keywords associated with endometriosis and sonography. Eighty-four trial and reviews published in English or French were included. Ovarian endometrioma can usually be diagnosed by a non-expert sonographer, especially when its aspect is typical. In case of an ovarian cyst with atypical presentation, it is recommended to control the sonography by a referent or to perform an MRI. In menopaused women, any ovarian cyst should be considered as a cancer until proven otherwise. In the diagnosis of posterior deep invasive endometriosis (DIE), TVS with sensitivity and specificity of 96 and 99% respectively, seems at least equivalent if not superior to MRI. However, these performances are related to expert sonographers. To reach sufficient efficiency in posterior DIE, the estimated learning curve for a sonographer is 44 cases. When posterior DIE is suspected, we recommend proposing a TVS "performed by an expert" or a MRI "at least interpreted by an expert". In anterior DIE, TVS has a good specificity (100%), but its sensitivity is poor in the literature (64%). TVS is therefore not able to eliminate the diagnosis. However a renal ultrasound should be proposed each time a urinary endometriosis is confirmed, and should be considered whenever posterior DIE is diagnosed especially the lesion is superior to 3cm. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Continuous terahertz-wave generation using a monolithically integrated horn antenna

Science.gov (United States)

Peytavit, E.; Beck, A.; Akalin, T.; Lampin, J.-F.; Hindle, F.; Yang, C.; Mouret, G.

2008-09-01

A transverse electromagnetic horn antenna is monolithically integrated with a standard ultrafast interdigitated electrode photodetector on low-temperature-grown GaAs. Continuous-wave terahertz radiation is generated at frequencies up to 2 THz with a maximum power of approximately 1 μW at 780 GHz. Experimental variations in the terahertz power as function of the frequency are explained by means of electromagnetic simulations of the antenna and the photomixer vicinity.

Real-time virtual sonography (RVS)-guided vacuum-assisted breast biopsy for lesions initially detected with breast MRI.

Science.gov (United States)

Uematsu, Takayoshi

2013-12-01

To report on our initial experiences with a new method of real-time virtual sonography (RVS)-guided 11-gauge vacuum-assisted breast biopsy for lesions that were initially detected with breast MRI. RVS-guided 11-gauge vacuum-assisted biopsy is performed when a lesion with suspicious characteristics is initially detected with breast MRI and is occult on mammography, sonography, and physical examination. Live sonographic images were co-registered to the previously loaded second-look spine contrast-enhanced breast MRI volume data to correlate the sonography and MR images. Six lesions were examined in six consecutive patients scheduled to undergo RVS-guided 11-gauge vacuum-assisted biopsy. One patient was removed from the study because of non-visualization of the lesion in the second-look spine contrast-enhanced breast MRI. Five patients with non-mass enhancement lesions were biopsied. The lesions ranged in size from 9 to 13 mm (mean 11 mm). The average procedural time, including the sonography and MR image co-registration time, was 25 min. All biopsies resulted in tissue retrieval. One was fibroadenomatous nodules, and those of four were fibrocystic changes. There were no complications during or after the procedures. RVS-guided 11-gauge vacuum-assisted breast biopsies provide a safe and effective method for the examination of suspicious lesions initially detected with MRI.

A continuous wave fan beam tomography system having a best estimating filter

International Nuclear Information System (INIS)

Gordon, B.M.

1982-01-01

A continuous wave fan beam tomographic system is described which continuously samples X-ray absorption values and a means of providing a best-estimate of the X-ray absorption values at discrete points in time determined by sampling signal s(t). The means to provide the best-estimate include a continuous filter having a frequency range defined by the geometry of the mechanical system. Errors due to the statistical variation in photon emissions of the X-ray source are thereby minimized and the effective signal-to-noise ratio of signals is enhanced, which in turn allows a significant reduction in radiation dosage. (author)

Clinical significance of neonatal parafrontal horn cysts detected by cranial sonography

International Nuclear Information System (INIS)

Woo, Jeong Joo; Jung, Myung Ja; Kim, Eun Ryung

2005-01-01

The describe the significance, incidence and characteristics of sonographic findings and long term outcomes of parafrontal horn cysts detected by screening cranial sonography done within the first week following birth. 2122 first cranial ultrasound scans performed over a five year period were retrospectively evaluated and 23 neonates with parafrontal horn cysts were found (which are different from secondary cystic lesions). 17 cases had a birth weight of 2400 gm with gestation between 34 and 41 weeks. The size, shape and location of the parafrontal horn cysts and other associated abnormalities shown on the cranial sonogram were evaluated and sequential ultrasound study, maternal records, neonatal events and neurodevelopmental evaluations were retrospectively assessed. Of the 23 subjects, 21 had isolated parafrontal horn cysts and 2 had subependymal hemorrhages. There was no record of any abnormal perinatal history. The cysts were bilateral in 20 neonates and unilateral in the others. The size of the cysts ranged from 3 to 18 mm in diameter (mean 9 mm). Sonographic features of the parafrontal horn cysts were distinctive morphology (elliptical, thin walled) and location (adjacent to the tip of the frontal horn). In 17 of the cases a follow-up cranial sonography was performed, and all parafrontal horn cysts disappeared within 3 to 6 months. Neurodevelopmental outcomes were normal in those 17 cases. Screening cranial sonography of neonates discovers isolated parafrontal horn cyst. The incidence of parafrontal horn cysts in neonates in our study was 1.1%. They are present in the first week following birth and resolve themselves without medical treatment within a few months. In addition, they show normal neurodevelopment. The parafrontal cysts are suspected to be a benign variant of normal neurodevelopment

Non-Contact Sensor for Long-Term Continuous Vital Signs Monitoring: A Review on Intelligent Phased-Array Doppler Sensor Design

Science.gov (United States)

Hall, Travis; Nguyen, Tam Q.; Mayeda, Jill C.; Lie, Paul E.; Lopez, Jerry; Banister, Ron E.

2017-01-01

It has been the dream of many scientists and engineers to realize a non-contact remote sensing system that can perform continuous, accurate and long-term monitoring of human vital signs as we have seen in many Sci-Fi movies. Having an intelligible sensor system that can measure and record key vital signs (such as heart rates and respiration rates) remotely and continuously without touching the patients, for example, can be an invaluable tool for physicians who need to make rapid life-and-death decisions. Such a sensor system can also effectively help physicians and patients making better informed decisions when patients’ long-term vital signs data is available. Therefore, there has been a lot of research activities on developing a non-contact sensor system that can monitor a patient’s vital signs and quickly transmit the information to healthcare professionals. Doppler-based radio-frequency (RF) non-contact vital signs (NCVS) monitoring system are particularly attractive for long term vital signs monitoring because there are no wires, electrodes, wearable devices, nor any contact-based sensors involved so the subjects may not be even aware of the ubiquitous monitoring. In this paper, we will provide a brief review on some latest development on NCVS sensors and compare them against a few novel and intelligent phased-array Doppler-based RF NCVS biosensors we have built in our labs. Some of our NCVS sensor tests were performed within a clutter-free anechoic chamber to mitigate the environmental clutters, while most tests were conducted within the typical Herman-Miller type office cubicle setting to mimic a more practical monitoring environment. Additionally, we will show the measurement data to demonstrate the feasibility of long-term NCVS monitoring. The measured data strongly suggests that our latest phased array NCVS system should be able to perform long-term vital signs monitoring intelligently and robustly, especially for situations where the subject is

Non-Contact Sensor for Long-Term Continuous Vital Signs Monitoring: A Review on Intelligent Phased-Array Doppler Sensor Design.

Science.gov (United States)

Hall, Travis; Lie, Donald Y C; Nguyen, Tam Q; Mayeda, Jill C; Lie, Paul E; Lopez, Jerry; Banister, Ron E

2017-11-15

It has been the dream of many scientists and engineers to realize a non-contact remote sensing system that can perform continuous, accurate and long-term monitoring of human vital signs as we have seen in many Sci-Fi movies. Having an intelligible sensor system that can measure and record key vital signs (such as heart rates and respiration rates) remotely and continuously without touching the patients, for example, can be an invaluable tool for physicians who need to make rapid life-and-death decisions. Such a sensor system can also effectively help physicians and patients making better informed decisions when patients' long-term vital signs data is available. Therefore, there has been a lot of research activities on developing a non-contact sensor system that can monitor a patient's vital signs and quickly transmit the information to healthcare professionals. Doppler-based radio-frequency (RF) non-contact vital signs (NCVS) monitoring system are particularly attractive for long term vital signs monitoring because there are no wires, electrodes, wearable devices, nor any contact-based sensors involved so the subjects may not be even aware of the ubiquitous monitoring. In this paper, we will provide a brief review on some latest development on NCVS sensors and compare them against a few novel and intelligent phased-array Doppler-based RF NCVS biosensors we have built in our labs. Some of our NCVS sensor tests were performed within a clutter-free anechoic chamber to mitigate the environmental clutters, while most tests were conducted within the typical Herman-Miller type office cubicle setting to mimic a more practical monitoring environment. Additionally, we will show the measurement data to demonstrate the feasibility of long-term NCVS monitoring. The measured data strongly suggests that our latest phased array NCVS system should be able to perform long-term vital signs monitoring intelligently and robustly, especially for situations where the subject is sleeping

Non-Contact Sensor for Long-Term Continuous Vital Signs Monitoring: A Review on Intelligent Phased-Array Doppler Sensor Design

Directory of Open Access Journals (Sweden)

Travis Hall

2017-11-01

Full Text Available It has been the dream of many scientists and engineers to realize a non-contact remote sensing system that can perform continuous, accurate and long-term monitoring of human vital signs as we have seen in many Sci-Fi movies. Having an intelligible sensor system that can measure and record key vital signs (such as heart rates and respiration rates remotely and continuously without touching the patients, for example, can be an invaluable tool for physicians who need to make rapid life-and-death decisions. Such a sensor system can also effectively help physicians and patients making better informed decisions when patients’ long-term vital signs data is available. Therefore, there has been a lot of research activities on developing a non-contact sensor system that can monitor a patient’s vital signs and quickly transmit the information to healthcare professionals. Doppler-based radio-frequency (RF non-contact vital signs (NCVS monitoring system are particularly attractive for long term vital signs monitoring because there are no wires, electrodes, wearable devices, nor any contact-based sensors involved so the subjects may not be even aware of the ubiquitous monitoring. In this paper, we will provide a brief review on some latest development on NCVS sensors and compare them against a few novel and intelligent phased-array Doppler-based RF NCVS biosensors we have built in our labs. Some of our NCVS sensor tests were performed within a clutter-free anechoic chamber to mitigate the environmental clutters, while most tests were conducted within the typical Herman-Miller type office cubicle setting to mimic a more practical monitoring environment. Additionally, we will show the measurement data to demonstrate the feasibility of long-term NCVS monitoring. The measured data strongly suggests that our latest phased array NCVS system should be able to perform long-term vital signs monitoring intelligently and robustly, especially for situations where the

Comparison of power Doppler and color Doppler ultrasonography in the detection of intrasticular blood flow of normal infants

International Nuclear Information System (INIS)

Shin, Sung Ran; Lee, Ho Kyoung; Lee, Won Gyun; Youk, Dong Joon; Rho, Taek Soo; Lee, Min Jin; Lee, Sang Chun

1999-01-01

To compare color Doppler ultrasonography (US) and power Doppler US in the detection of intratesticular blood flow in normal infants and to asses the symmetry of blood flow. Testicular blood flow was assessed prospectively in 100 testes of 50 infants with both power and color Doppler US. We compared the power Doppler with color Doppler to detect intratesticular blood. When the flow was detected, intratesticular blood flow was graded as follows: grade 1: single intratesticular Doppler signal ; grade 2: multiple intratesticular Doppler signals. The symmetry of intratesticular flow was assessed by using the same method. Intratesticular flow was detected in 72 (72%) and 68 (68%) testes on power and color Doppler US, respectively. In 76 testes (76%), intratesticular flow was detected in either one or both techniques. On power Doppler US, grade 1 was seen in 40 tests and grade 2 in 32 testes. On color Doppler US, grade 1 was noted in 52 testes and grade 2 in 16 testes. Testicular blood flow was symmetric on both power and color Doppler US in each patient. There was no difference between power Doppler and color Doppler ultrasonography in detecting intratesticular blood flow in normal infants.

Principles of doppler tomography

International Nuclear Information System (INIS)

Juhlin, P.

1992-08-01

This paper shows how the radon transform can be used to determine vector fields. A scheme to determine the velocity field of a moving fluid by measurements with a continuous doppler signal is suggested. When the flow is confined to a bounded domain, as is the case in most applications, it can be uniquely decomposed into one gradiental and one rotational part. The former vanishes if the fluid is incompressible and source-free, and the latter can be completely reconstructed by the methods proposed in this paper if the domain is simply connected. Special attention is paid to laminar flow in a long cylindrical vessel with circular cross-section. Under such conditions the flow profile becomes parabolic, which makes the vessel recognizable as a typical 'N-shaped' pattern in an image describing the rotation of the velocity field. The vessel yields the same doppler tomographic pattern, no matter how it is sectioned. The ideas presented should be applicable also when studying the flow in blood vessels, even if the flow profile in these is not quite parabolic. The discrepancies only make the 'N-shape' somewhat distorted

Ultrasonic colour Doppler imaging

DEFF Research Database (Denmark)

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

2011-01-01

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...... 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...... 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...

Evaluation of hepatic venous pulsatility and portal venous velocity with doppler ultrasonography during the puerperium

Energy Technology Data Exchange (ETDEWEB)

Pekindil, Goekhan [Department of Radiology, Trakya University School of Medicine, 22030 Edirne (Turkey); Varol, Fuesun G. [Department of Obstetrics and Gynecology, Trakya University School of Medicine, 22030 Edirne (Turkey); Ali Yuece, M. [Department of Obstetrics and Gynecology, Trakya University School of Medicine, 22030 Edirne (Turkey); Yardim, Turgut [Department of Obstetrics and Gynecology, Trakya University School of Medicine, 22030 Edirne (Turkey)

1999-03-01

Objective: The aim of this study is to evaluate pregnancy-induced changes of hepatic venous pulsatility and portal venous velocity in the puerperium and to determine if these changes disappeared by the end of the puerperium. Methods and material: Healthy normal volunteers (90) were examined on the 2nd and 7th days of puerperium and between the 6th and 8th weeks postpartum. Doppler waveform patterns were obtained in the middle hepatic vein and main portal vein. The hepatic venous pulsatility was named as normal, damped or flat. Results: On the 2nd day postpartum, the hepatic vein pulsatility was shown as normal in 8 (26%), damped in 11 (37%) and flat in 11 (37%) cases. On the 7th day postpartum, 15 (50%) cases had normal, 9 (30%) cases had dampened, and 6 (20%) cases had still flat pattern. The majority of the cases (60%) displayed normal hepatic venous pulsatility in the 6th and 8th weeks of puerperium, whereas 23% had still dampened and 17% had flat patterns. There was a trend toward normal pulsatility with increasing puerperal age. The mean portal venous velocity was still higher than the non-pregnant levels and did not showed significant alterations during puerperium. Conclusion: This study emphasised that, since pregnancy-induced alterations in hepatic venous pulsatility and portal venous velocity had not completely returned to normal in most cases until the end of the puerperium, these physiological changes should be considered whenever hepatic and portal systems are interpreted with Doppler sonography during the puerperal period.

Evaluation of hepatic venous pulsatility and portal venous velocity with doppler ultrasonography during the puerperium

International Nuclear Information System (INIS)

Pekindil, Goekhan; Varol, Fuesun G.; Ali Yuece, M.; Yardim, Turgut

1999-01-01

Objective: The aim of this study is to evaluate pregnancy-induced changes of hepatic venous pulsatility and portal venous velocity in the puerperium and to determine if these changes disappeared by the end of the puerperium. Methods and material: Healthy normal volunteers (90) were examined on the 2nd and 7th days of puerperium and between the 6th and 8th weeks postpartum. Doppler waveform patterns were obtained in the middle hepatic vein and main portal vein. The hepatic venous pulsatility was named as normal, damped or flat. Results: On the 2nd day postpartum, the hepatic vein pulsatility was shown as normal in 8 (26%), damped in 11 (37%) and flat in 11 (37%) cases. On the 7th day postpartum, 15 (50%) cases had normal, 9 (30%) cases had dampened, and 6 (20%) cases had still flat pattern. The majority of the cases (60%) displayed normal hepatic venous pulsatility in the 6th and 8th weeks of puerperium, whereas 23% had still dampened and 17% had flat patterns. There was a trend toward normal pulsatility with increasing puerperal age. The mean portal venous velocity was still higher than the non-pregnant levels and did not showed significant alterations during puerperium. Conclusion: This study emphasised that, since pregnancy-induced alterations in hepatic venous pulsatility and portal venous velocity had not completely returned to normal in most cases until the end of the puerperium, these physiological changes should be considered whenever hepatic and portal systems are interpreted with Doppler sonography during the puerperal period

“Focal thyroid inferno” on color Doppler ultrasonography: A specific feature of focal Hashimoto's thyroiditis

International Nuclear Information System (INIS)

Fu, Xianshui; Guo, Limei; Zhang, Huabin; Ran, Weiqiang; Fu, Peng; Li, Zhiqiang; Chen, Wen; Jiang, Ling; Wang, Jinrui; Jia, Jianwen

2012-01-01

Purpose: To evaluate color-Doppler features predictive of focal Hashimoto's thyroiditis. Materials and methods: A total of 521 patients with 561 thyroid nodules that underwent surgeries or gun biopsies were included in this study. These nodules were divided into three groups: focal Hashimoto's thyroiditis (104 nodules in 101 patients), benignity other than focal Hashimoto's thyroiditis (73 nodules in 70 patients), and malignancy (358 nodules in 350 patients). On color Doppler sonography, four vascularity types were determined as: hypovascularity, marked internal flow, marked peripheral flow and focal thyroid inferno. The χ 2 test was performed to seek the potential vascularity type with the predictive ability of certain thyroid pathology. Furthermore, the gray-scale features of each nodule were also studied. Results: The vascularity type I (hypovascularity) was more often seen in focal Hashimoto's thyroiditis than other benignity and malignancy (46% vs. 20.5% and 19%). While the type II (marked internal flow) showed the opposite tendency (26.9% [focal Hashimoto's thyroiditis] vs. 45.2% [other benignity] and 52.8% [malignancy]). However, type III (marked peripheral flow) was unable to predict any thyroid pathology. Importantly, type IV (focal thyroid inferno) was exclusive to focal Hashimoto's thyroiditis. All 8 type IV nodules appeared to be solid, hypoechoic, and well-defined. Using “focal thyroid inferno” as an indicator of FHT, the diagnostic sensitivity and specificity were 7.7% and 100% respectively. Conclusions: The vascularity type of “focal thyroid inferno” is specific for focal Hashimoto thyroiditis. Recognition of this particular feature may avoid unnecessary interventional procedures for some solid hypoechoic thyroid nodules suspicious of malignancy.

Locally advanced breast cancer: comparison of mammography, sonography and MR imaging in evaluation of residual disease in women receiving neoadjuvant chemotherapy

International Nuclear Information System (INIS)

Londero, Viviana; Bazzocchi, Massimo; Del Frate, Chiara; Francescutti, Giuliana; Zuiani, Chiara; Puglisi, Fabio; Di Loreto, Carla

2004-01-01

The accuracy of mammography, sonography and magnetic resonance imaging (MRI) in identifying residual disease after neoadjuvant chemotherapy is evaluated and imaging findings are correlated with pathologic findings. Fifteen patients enrolled in an experimental protocol of preoperative neoadjuvant chemotherapy underwent clinical examination, mammography, sonography and dynamic MRI, performed in this order, before and respectively after 2 and 4 cycles of neoadjuvant chemotherapy. Four radiologists, two for mammography, one for sonography and one for MR, examined the images, blinded to the results of the other examinations. All patients underwent radical or conservative surgery, and imaging findings were compared with pathologic findings. MRI identified 2/15 (13.3.%) clinically complete response (CR), 9/15 (60%) partial response (PR), 3/15 (20%) stable disease (SD) and 1/15 (6.7%) progressive disease. Mammography identified 1/15 (6.7%) clinically CR, 8/15 (53.3%) PR and 4/15 (27%) SD, and was not able to evaluate the disease in 2/15 (13%) cases. Sonography presented the same results as MRI. Therefore, MRI and sonography compared to mammography correctly identified residual disease in 100 vs. 86%. MRI resulted in two false-negative results because of the presence of microfoci of in situ ductal carcinoma (DCIS) and invasive lobular carcinoma (LCI). MRI was superior to mammography in cases of multifocal or multicentric disease (83 vs. 33%). Sonography performed after MRI improves the accuracy in evaluation of uncertain foci of multifocal disease seen on MR images with an increase of diagnostic accuracy from 73 to 84.5%. MRI assesses response to neoadjuvant chemotherapy better than traditional methods of physical examination and mammography. (orig.)

Locally advanced breast cancer: comparison of mammography, sonography and MR imaging in evaluation of residual disease in women receiving neoadjuvant chemotherapy

Energy Technology Data Exchange (ETDEWEB)

Londero, Viviana; Bazzocchi, Massimo; Del Frate, Chiara; Francescutti, Giuliana; Zuiani, Chiara [Institute of Radiology, University of Udine, via Colugna 50, 33100, Udine (Italy); Puglisi, Fabio [Department of Oncology, University of Udine, via Colugna 50, 33100, Udine (Italy); Di Loreto, Carla [Institute of Pathology, University of Udine, via Colugna 50, 33100, Udine (Italy)

2004-08-01

The accuracy of mammography, sonography and magnetic resonance imaging (MRI) in identifying residual disease after neoadjuvant chemotherapy is evaluated and imaging findings are correlated with pathologic findings. Fifteen patients enrolled in an experimental protocol of preoperative neoadjuvant chemotherapy underwent clinical examination, mammography, sonography and dynamic MRI, performed in this order, before and respectively after 2 and 4 cycles of neoadjuvant chemotherapy. Four radiologists, two for mammography, one for sonography and one for MR, examined the images, blinded to the results of the other examinations. All patients underwent radical or conservative surgery, and imaging findings were compared with pathologic findings. MRI identified 2/15 (13.3.%) clinically complete response (CR), 9/15 (60%) partial response (PR), 3/15 (20%) stable disease (SD) and 1/15 (6.7%) progressive disease. Mammography identified 1/15 (6.7%) clinically CR, 8/15 (53.3%) PR and 4/15 (27%) SD, and was not able to evaluate the disease in 2/15 (13%) cases. Sonography presented the same results as MRI. Therefore, MRI and sonography compared to mammography correctly identified residual disease in 100 vs. 86%. MRI resulted in two false-negative results because of the presence of microfoci of in situ ductal carcinoma (DCIS) and invasive lobular carcinoma (LCI). MRI was superior to mammography in cases of multifocal or multicentric disease (83 vs. 33%). Sonography performed after MRI improves the accuracy in evaluation of uncertain foci of multifocal disease seen on MR images with an increase of diagnostic accuracy from 73 to 84.5%. MRI assesses response to neoadjuvant chemotherapy better than traditional methods of physical examination and mammography. (orig.)

New phase method of measuring particle size with laser Doppler radar

Science.gov (United States)

Zemlianskii, Vladimir M.

1996-06-01

A vast field of non-contact metrology, vibrometry, dynamics and microdynamics problems solved on the basis of laser Doppler method resulted in the development of great variety of laser Doppler radar (LDR). In coherent LDR few beams with various polarization are generally adopted, that are directed at the zone of measurement, through which the probing air stream moves. Studies of various coherent LDR demonstrated that polarization-phase effects of scattering can in some cases considerably effect on the signal-to-noise ratio of the Doppler signal. On the other side using phase effects can simultaneous measurement of size and velocity of spherical particles. New possibilities for improving the accuracy of measuring spherical particles' sizes come to light when application is made in coherent LDR of two waves- probing and one out of the types of symmetrical reception of scattered radiation, during which phase-conjugate signals are formed. The theoretical analysis on the basis of the scattering theory showed, that in symmetrical reception of scattered radiation with respect to the planes OXZ and OYZ output signal of the photoreceiver contains two high- frequency signal components, which in relation to parameters of the probing and size, can either be in phase or antiphase. Results of numerical modeling are presented: amplitude of high frequency signal, coefficient of phase and polarization matching of mixed waves, the depths of photocurrent modulation and also signal's phase in relation to the angle between the probing beams. Phase method of determining particle's sizes based on the use of two wavelengths probing and symmetrical reception of scattered radiation in which conditions for the formation of phase conjugated high-frequency signals are satisfied is presented.

The masked educator-innovative simulation in an Australian undergraduate Medical Sonography and Medical Imaging program.

Science.gov (United States)

Reid-Searl, Kerry; Bowman, Anita; McAllister, Margaret; Cowling, Cynthia; Spuur, Kelly

2014-12-01

Clinical learning experiences for sonography and medical imaging students can sometimes involve the practice of technical procedures with less of a focus on developing communication skills with patients. Whilst patient-based simulation scenarios have been widely reported in other health education programmes, there is a paucity of research in sonography and medical imaging. The aim of this study was to explore the effectiveness of Mask-Ed™ (KRS Simulation) in the learning and teaching of clinical communication skills to undergraduate medical sonography and medical imaging students. Mask-Ed™ (KRS Simulation) is a simulation technique where the educator is hidden behind wearable realistic silicone body props including masks. Focus group interviews were conducted with 11 undergraduate medical sonography and medical imaging students at CQUniversity, Australia. The number of participants was limited to the size of the cohort of students enrolled in the course. Prior to these interviews participants were engaged in learning activities that featured the use of the Mask-Ed™ (KRS Simulation) method. Thematic analysis was employed to explore how the introduction of Mask-Ed™ (KRS Simulation) contributed to students' learning in relation to clinical communication skills. Key themes included: benefits of interacting with someone real rather than another student, learning made fun, awareness of empathy, therapeutic communication skills, engaged problem solving and purposeful reflection. Mask-Ed™ (KRS Simulation) combined with interactive sessions with an expert facilitator, contributed positively to students' learning in relation to clinical communication skills. Participants believed that interacting with someone real, as in the Mask-Ed characters was beneficial. In addition to the learning being described as fun, participants gained an awareness of empathy, therapeutic communication skills, engaged problem solving and purposeful reflection.

Demonstration of coherent Doppler lidar for navigation in GPS-denied environments

Science.gov (United States)

Amzajerdian, Farzin; Hines, Glenn D.; Pierrottet, Diego F.; Barnes, Bruce W.; Petway, Larry B.; Carson, John M.

2017-05-01

A coherent Doppler lidar has been developed to address NASA's need for a high-performance, compact, and cost-effective velocity and altitude sensor onboard its landing vehicles. Future robotic and manned missions to solar system bodies require precise ground-relative velocity vector and altitude data to execute complex descent maneuvers and safe, soft landing at a pre-designated site. This lidar sensor, referred to as a Navigation Doppler Lidar (NDL), meets the required performance of the landing missions while complying with vehicle size, mass, and power constraints. Operating from up to four kilometers altitude, the NDL obtains velocity and range precision measurements reaching 2 cm/sec and 2 meters, respectively, dominated by the vehicle motion. Terrestrial aerial vehicles will also benefit from NDL data products as enhancement or replacement to GPS systems when GPS is unavailable or redundancy is needed. The NDL offers a viable option to aircraft navigation in areas where the GPS signal can be blocked or jammed by intentional or unintentional interference. The NDL transmits three laser beams at different pointing angles toward the ground to measure range and velocity along each beam using a frequency modulated continuous wave (FMCW) technique. The three line-of-sight measurements are then combined in order to determine the three components of the vehicle velocity vector and its altitude relative to the ground. This paper describes the performance and capabilities that the NDL demonstrated through extensive ground tests, helicopter flight tests, and onboard an autonomous rocket-powered test vehicle while operating in closedloop with a guidance, navigation, and control (GN and C) system.

Prenatal diagnosis of the Dandy-Walker syndrome by sonography and computed tomography

International Nuclear Information System (INIS)

Toelly, E.; Ebner, F.; Oberbauer, R.W.

1984-01-01

A case of Dandy-Walker-syndrome is presented, comparing the value of sonography and CT in intrauterine diagnosis. Together with a review of the literature of the subject, pathogenesis, morphology and prognosis in regard to the psychomotoric development are discussed. (orig.) [de

Prospects of detecting gravitational background radiation by Doppler tracking interplanetary spacecraft

International Nuclear Information System (INIS)

Bertotti, B.; Carr, B.J.

1980-01-01

We examine the theoretical and experimental prospects of detecting a low-frequency, continuous, stochastic background of gravitational waves by Doppler tracking interplanetary spacecraft. From a theoretical standpoint, such a background may have been generated by various postgalactic processes or by pregalactic black hole formation; there could also exist a primordial background which goes back to the beginning of the universe. We review the characteristic frequency and density ranges which one might anticipate for these backgrounds. From an experimental standpoint, one's ability to detect a background is limited by the finite length of the record available and by an imperfect knowledge of the spectrum of various sources of noise. The fundamental contribution to the noise comes from the clock which regulates the frequency of the tracking waves. If one uses a hydrogen maser clock, this noise becomes progressively less important with decreasing frequency: one might hope to detect a critical density of background radiation at frequencies below 10 -2 Hz and a background with 10 -4 times the critical density at frequencies below 10 -5 Hz. It is encouraging that some of the sorts of background which we anticipate from theoretical considerations fall within the observable regime. We discuss the extent to which other sources of noise may exceed the clock noise and the degree to which they can be eliminated

Gallblader varices in children with portal cavernoma: duplex-Doppler and color Doppler ultrasound studies

International Nuclear Information System (INIS)

Muro, D.; Sanguesa, C.; Lopez, A.

1998-01-01

To determine the prevalence of varices in the gallbladder wall, observed by duplex-Doppler and color Doppler ultrasound, in children with cavernoma of the portal vein. Nineteen patients with portal hypertension were studied prospectively by duplex-Doppler and color Doppler ultrasound: 12 of the patients had developed a cavernoma of the portal vein. The presence of peri vesicular varices was assessed in the group of patients with portal cavernoma. Duplex-Doppler and color Doppler ultrasound disclosed the presence of varices in gallbladder wall in nine of the 12 patients (75%). The varices appeared as anechoic and serpiginous areas, and Doppler ultrasound revealed slowed venous flow. However, the three patients in whom gallbldder varices were not detected presented collateral gastric ciculation and spontaneous splenorenal shunt. Gallbladder varices are common in children with portal vein cavernoma; they present hepatopetal flow. Their developments is not related to the size of the portal cavernoma, the presence of spontaneous portosystemic shunts, or endoscopic obliteration of gastric and esophageal varices. The detection of gallbladder varices in patients with portal hypertension who are to undergo biliary surgery is highly important for the surgeon, helping to avoid perioperative complications. (Author) 15 refs

Traveling-wave solutions in continuous chains of unidirectionally coupled oscillators

Science.gov (United States)

Glyzin, S. D.; Kolesov, A. Yu; Rozov, N. Kh

2017-12-01

Proposed is a mathematical model of a continuous annular chain of unidirectionally coupled generators given by certain nonlinear advection-type hyperbolic boundary value problem. Such problems are constructed by a limit transition from annular chains of unidirectionally coupled ordinary differential equations with an unbounded increase in the number of links. It is shown that any preassigned finite number of stable periodic motions of the traveling-wave type can coexist in the model.

Parametric Investigation of Laser Doppler Microphones

Science.gov (United States)

Daoud, M.; Naguib, A.

2002-11-01

The concept of a Laser Doppler Microphone (LDM) is based on utilizing the Doppler frequency shift of a focused laser beam to measure the unsteady velocity of the center point of a flexible polymer diaphragm that is mounted on top of a hole and subjected to the unsteady pressure. Time integration of the velocity signal yields a time series of the diaphragm displacement, which can be converted to pressure from knowledge of the sensor's deflection sensitivity. In our APS/DFD presentation last year, the stringent frequency resolution requirement of these new sensors and methods to meet this requirement were discussed. Here, the dependence of the sensor characteristics (sensitivity, bandwidth, and noise floor) on various significant parameters is investigated in detail by calibrating the sensor in a plane wave tube in the frequency range of 50 - 5000 Hz. Parameters investigated include sensor diaphragm material and thickness, sensor size, damping of the diaphragm motion and laser beam spot size. The results shed light on the operating limits of the new sensor and demonstrate its ability to conduct high-spatial-resolution measurements in typical high-Reynolds-number test facilities. Moreover, calibrated LDM sensors were used to conduct measurements in a separating/reattaching flow and the results are compared to classical electret-type microphones with a similar sensing diameter.

Bound states embedded into continuous spectrum as 'gathered' (compactified) scattering waves

International Nuclear Information System (INIS)

Zakhar'ev, B.N.; Chabanov, V.M.

1995-01-01

It is shown that states of continuous spectrum (the half-line case) can be considered as bound states normalized by unity but distributed on the infinite interval with vanishing density. Then the algorithms of shifting the range of primary localization of a chosen bound state in potential well of finite width appear to be applicable to scattering functions. The potential perturbations of the same type (but now on half-axis) concentrate the scattering wave in near vicinity of the origin, which leads to creation of bound state embedded into continuous spectrum. (author). 8 refs., 7 figs

Differentiation of widely invasive and minimally invasive follicular thyroid carcinoma with sonography

International Nuclear Information System (INIS)

Shin, Jung Hee; Han, Boo-Kyung; Ko, Eun Young; Oh, Young Lyun; Kim, Jung Han

2010-01-01

Purpose: We evaluated the sonographic findings that can help differentiate widely invasive follicular thyroid carcinomas (WIFTC) from minimally invasive follicular thyroid carcinomas (MIFTC). Methods: We retrospectively compared the sonographic and clinical findings of 24 patients (M:F = 5:19) with 24 MIFTCs and 12 patients (M:F = 1:11) with 13 WIFTCs that were confirmed pathologically and available in sonography at our institution between 1995 and 2007. Results: WIFTC was more common in elderly patients than MIFTC (p < 0.0001). WIFTC was seen with a larger size than MIFTC (p = 0.0092). The best cut-off values for age and size were 49 years and 5.6 cm, respectively. On sonography, all tumors were seen as a well-defined oval or round mass. Heterogeneous mulberry-like echotexture was more common for WIFTC than for MIFTC (77% vs. 25%) (p = 0.0046). The presence of calcifications was more frequent in WIFTC than in MIFTC (54% vs. 8%) (p = 0.0041). Ring calcifications (86%) were the most common type for WIFTC. WIFTC was commonly hypoechoic (70%) and rarely cystic change (8%), but without statistical differences. When WIFTCs represented tumors with two or more findings with a statistical difference, the specificity was 96%. Conclusion: WIFTC is distinguishable from MIFTC by sonography for patients with an age ≥49 years, a tumor ≥5.6 cm, a heterogeneous mulberry-like echotexure, or the presence of calcifications. The sonographic impression of a WIFTC can support a preoperative or intraoperative diagnosis of a difficult case as determined by FNA or with a frozen section.

Diagnostic Methods for Predicting Performance Impairment Associated With Combat Stress

National Research Council Canada - National Science Library

Matthews, Gerald; Warm, Joel S; Washburn, David

2004-01-01

.... The research focuses especially on the measurement of cerebral bloodflow using transcranial doppler sonography, together with additional indices including salivary cortisol and subjective stress state...

A comparison of cell-free placental messenger ribonucleic acid and color Doppler ultrasound for the prediction of placental invasion in patients with placenta accreta.

Science.gov (United States)

Naghshineh, Elham; Khorvash, Elahe; Kamali, Sara

2015-01-01

The aim of the present study was to comparison between cell-free placental messenger ribonucleic acid (mRNA) and Doppler ultrasound for the prediction of placental invasion in women with placenta accreta. In this cross-sectional study, 50 pregnant women at risk for placenta accreta underwent color Doppler and assessment of cell-free placental mRNA. Real-time reverse-transcription polymerase chain reaction was used for measurement of cell-free placental mRNA in maternal plasma. Based on the findings at cesarean delivery and histological examination, patients were divided into two groups of women with and without placenta accrete. To compare of the mean of mRNA levels between the two groups we used independent t-test and to compare of the mean of age and gestational age at sonography we used Mann-Whitney test. For determination of sensitivity and specificity and the cut-off point of mRNA levels we used the receiver operating characteristic curve. A total of 50 women with a mean age of 30.24 ± 4.905 years entered the study and 12 (24%) patients were diagnosed with placenta accreta. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of Doppler ultrasound were 83.3%, 78.9%, 56% and 94%, respectively. Results of our study showed if we consider a cut-off point equal to 3.325, with sensitivity and specificity of 0.917 and 0.789, respectively and the sensitivity, specificity, PPV and NPV of mRNA with were cut-off point of 3.325 were 91.7%, 78.9%, 57.9% and 96.8%, respectively. Cell-free mRNA is an acceptable, easy made, functional test with sensitivity, specificity, PPV and NPV more than Doppler ultrasound for diagnosis and prediction of incidence of placenta accrete and we recommend the use of cell-free mRNA test for diagnosis of placenta accreta.

Doppler optical coherence microscopy and tomography applied to inner ear mechanics

Energy Technology Data Exchange (ETDEWEB)

Page, Scott; Freeman, Dennis M. [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts (United States); Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts (United States); Ghaffari, Roozbeh [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts (United States)

2015-12-31

While it is clear that cochlear traveling waves underlie the extraordinary sensitivity, frequency selectivity, and dynamic range of mammalian hearing, the underlying micromechanical mechanisms remain unresolved. Recent advances in low coherence measurement techniques show promise over traditional laser Doppler vibrometry and video microscopy, which are limited by low reflectivities of cochlear structures and restricted optical access. Doppler optical coherence tomography (DOCT) and Doppler optical coherence microscopy (DOCM) both utilize a broadband source to limit constructive interference of scattered light to a small axial depth called a coherence gate. The coherence gate can be swept axially to image and measure sub-nanometer motions of cochlear structures throughout the cochlear partition. The coherence gate of DOCT is generally narrower than the confocal gate of the focusing optics, enabling increased axial resolution (typically 15 μm) within optical sections of the cochlear partition. DOCM, frequently implemented in the time domain, centers the coherence gate on the focal plane, achieving enhanced lateral and axial resolution when the confocal gate is narrower than the coherence gate. We compare these two complementary systems and demonstrate their utility in studying cellular and micromechanical mechanisms involved in mammalian hearing.

Directional nonlinear guided wave mixing: Case study of counter-propagating shear horizontal waves

Science.gov (United States)

Hasanian, Mostafa; Lissenden, Cliff J.

2018-04-01

While much nonlinear ultrasonics research has been conducted on higher harmonic generation, wave mixing provides the potential for sensitive measurements of incipient damage unencumbered by instrumentation nonlinearity. Studies of nonlinear ultrasonic wave mixing, both collinear and noncollinear, for bulk waves have shown the robust capability of wave mixing for early damage detection. One merit of bulk wave mixing lies in their non-dispersive nature, but guided waves enable inspection of otherwise inaccessible material and a variety of mixing options. Co-directional guided wave mixing was studied previously, but arbitrary direction guided wave mixing has not been addressed until recently. Wave vector analysis is applied to study variable mixing angles to find wave mode triplets (two primary waves and a secondary wave) resulting in the phase matching condition. As a case study, counter-propagating Shear Horizontal (SH) guided wave mixing is analyzed. SH wave interactions generate a secondary Lamb wave mode that is readily receivable. Reception of the secondary Lamb wave mode is compared for an angle beam transducer, an air coupled transducer, and a laser Doppler vibrometer (LDV). Results from the angle beam and air coupled transducers are quite consistent, while the LDV measurement is plagued by variability issues.

Interactive Simulation and Visualization of Lamb Wave Propagation in Isotropic and Anisotropic Structures

International Nuclear Information System (INIS)

Moll, J; Schulte, R T; Fritzen, C-P; Rezk-Salama, C; Klinkert, T; Kolb, A

2011-01-01

Structural health monitoring systems allow a continuous surveillance of the structural integrity of operational systems. As a result, it is possible to reduce time and costs for maintenance without decreasing the level of safety. In this paper, an integrated simulation and visualization environment is presented that enables a detailed study of Lamb wave propagation in isotropic and anisotropic materials. Thus, valuable information about the nature of Lamb wave propagation and its interaction with structural defects become available. The well-known spectral finite element method is implemented to enable a time-efficient calculation of the wave propagation problem. The results are displayed in an interactive visualization framework accounting for the human perception that is much more sensitive to motion than to changes in color. In addition, measurements have been conducted experimentally to record the full out-of-plane wave-field using a Laser-Doppler vibrometry setup. An aluminum structure with two synthetic cuts has been investigated, where the elongated defects have a different orientation with respect to the piezoelectric actuator. The resulting wave-field is also displayed interactively showing that the scattered wave-field at the defect is highly directional.

Temporal variability of tidal and gravity waves during a record long 10-day continuous lidar sounding

Science.gov (United States)

Baumgarten, Kathrin; Gerding, Michael; Baumgarten, Gerd; Lübken, Franz-Josef

2018-01-01

Gravity waves (GWs) as well as solar tides are a key driving mechanism for the circulation in the Earth's atmosphere. The propagation of gravity waves is strongly affected by tidal waves as they modulate the mean background wind field and vice versa, which is not yet fully understood and not adequately implemented in many circulation models. The daylight-capable Rayleigh-Mie-Raman (RMR) lidar at Kühlungsborn (54° N, 12° E) typically provides temperature data to investigate both wave phenomena during one full day or several consecutive days in the middle atmosphere between 30 and 75 km altitude. Outstanding weather conditions in May 2016 allowed for an unprecedented 10-day continuous lidar measurement, which shows a large variability of gravity waves and tides on timescales of days. Using a one-dimensional spectral filtering technique, gravity and tidal waves are separated according to their specific periods or vertical wavelengths, and their temporal evolution is studied. During the measurement period a strong 24 h wave occurs only between 40 and 60 km and vanishes after a few days. The disappearance is related to an enhancement of gravity waves with periods of 4-8 h. Wind data provided by ECMWF are used to analyze the meteorological situation at our site. The local wind structure changes during the observation period, which leads to different propagation conditions for gravity waves in the last days of the measurement period and therefore a strong GW activity. The analysis indicates a further change in wave-wave interaction resulting in a minimum of the 24 h tide. The observed variability of tides and gravity waves on timescales of a few days clearly demonstrates the importance of continuous measurements with high temporal and spatial resolution to detect interaction phenomena, which can help to improve parametrization schemes of GWs in general circulation models.

Generation of continuous-wave 194 nm laser for mercury ion optical frequency standard

Science.gov (United States)

Zou, Hongxin; Wu, Yue; Chen, Guozhu; Shen, Yong; Liu, Qu; Precision measurement; atomic clock Team

2015-05-01

194 nm continuous-wave (CW) laser is an essential part in mercury ion optical frequency standard. The continuous-wave tunable radiation sources in the deep ultraviolet (DUV) region of the spectrum is also serviceable in high-resolution spectroscopy with many atomic and molecular lines. We introduce a scheme to generate continuous-wave 194 nm radiation with SFM in a Beta Barium Borate (BBO) crystal here. The two source beams are at 718 nm and 266 nm, respectively. Due to the property of BBO, critical phase matching (CPM) is implemented. One bow-tie cavity is used to resonantly enhance the 718 nm beam while the 266 nm makes a single pass, which makes the configuration easy to implement. Considering the walk-off effect in CPM, the cavity mode is designed to be elliptical so that the conversion efficiency can be promoted. Since the 266 nm radiation is generated by a 532 nm laser through SHG in a BBO crystal with a large walk-off angle, the output mode is quite non-Gaussian. To improve mode matching, we shaped the 266 nm beam into Gaussian modes with a cylindrical lens and iris diaphragm. As a result, 2.05 mW 194 nm radiation can be generated. As we know, this is the highest power for 194 nm CW laser using SFM in BBO with just single resonance. The work is supported by the National Natural Science Foundation of China (Grant No. 91436103 and No. 11204374).

Avaliação dos tumores hepáticos ao Doppler Doppler evaluation of liver tumors

Directory of Open Access Journals (Sweden)

Márcio Martins Machado

2004-10-01

Full Text Available Os avanços recentes na ultra-sonografia têm ampliado a possibilidade de detecção de tumores hepáticos. Isto tem auxiliado na perspectiva de melhora do prognóstico destes pacientes, à medida que novas técnicas terapêuticas têm surgido. Neste artigo os autores relatam achados ao Doppler que podem auxiliar na identificação e caracterização dos tumores hepáticos, avaliando dados do Doppler colorido, pulsado e do Doppler de amplitude ("power Doppler". Fazem, também, referência a novas modalidades de imagem, como o uso da harmônica.Recent advances in ultrasound have optimized the detection of liver tumors and helped to improve the prognosis of patients with this condition as newly developed and improved therapeutic modalities have been established. The authors review important Doppler findings which may help in the identification and characterization of some hepatic tumors through the evaluation of color Doppler, pulsed Doppler and power Doppler features. New imaging methods such as the use of harmonics imaging are also reviewed.

Solitary waves of surface plasmon polariton via phase shifts under Doppler broadening and Kerr nonlinearity

Science.gov (United States)

Ahmad, S.; Ahmad, A.; Bacha, B. A.; Khan, A. A.; Abdul Jabar, M. S.

2017-12-01

Surface Plasmon Polaritons (SPPs) are theoretically investigated at the interface of a dielectric metal and gold. The output pulse from the dielectric is used as the input pulse for the generation of SPPs. The SPPs show soliton-like behavior at the interface. The solitary form of a SPP is maintained under the effects of Kerr nonlinearity, Doppler broadening and Fresnel dragging whereas its phase shift is significantly modified. A 0.3radian phase shift is calculated in the presence of both Kerr nonlinearity and Fresnel dragging in the absence of plasma motion. The phase shift is enhanced to 60radian due to the combined effect of Doppler broadening, Kerr nonlinearity and Fresnel dragging. The results may have significant applications in nano-photonics, optical tweezers, photovoltaic devices, plasmonster and sensing technology.

Labor analgesia in parturients of fetal growth restriction having raised umbilical Doppler vascular indices

Directory of Open Access Journals (Sweden)

Sukhen Samanta

2018-01-01

Conclusions: Continuous epidural ropivacaine causes improved fetoplacental circulation in parturients with growth-restricted fetuses having raised Doppler indices during labor analgesia. We also found better neonatal outcome with continuous infusion of epidural ropivacaine as compared to IM tramadol.

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

International Nuclear Information System (INIS)

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

1997-01-01

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

Effect of suprathermal electrons on the intensity and Doppler frequency of electron plasma lines

Directory of Open Access Journals (Sweden)

P. Guio

Full Text Available In an incoherent scattering radar experiment, the spectral measurement of the so-called up- and downshifted electron plasma lines provides information about their intensity and their Doppler frequency. These two spectral lines correspond, in the backscatter geometry, to two Langmuir waves travelling towards and away from the radar. In the daytime ionosphere, the presence of a small percentage of photoelectrons produced by the solar EUV of the total electron population can excite or damp these Langmuir waves above the thermal equilibrium, resulting in an enhancement of the intensity of the lines above the thermal level. The presence of photo-electrons also modifies the dielectric response function of the plasma from the Maxwellian and thus influences the Doppler frequency of the plasma lines. In this paper, we present a high time-resolution plasma-line data set collected on the Eiscat VHF radar. The analysed data are compared with a model that includes the effect of a suprathermal electron population calculated by a transport code. By comparing the intensity of the analysed plasma lines data to our model, we show that two sharp peaks in the electron suprathermal distribution in the energy range 20-30 eV causes an increased Landau damping around 24.25 eV and 26.25 eV. We have identified these two sharp peaks as the effect of the photoionisation of N₂ and O by the intense flux of monochromatic HeII radiation of wavelength 30.378 nm (40.812 eV created in the chromospheric network and coronal holes. Furthermore, we see that what would have been interpreted as a mean Doppler drift velocity for a Maxwellian plasma is actually a shift of the Doppler frequency of the plasma lines due to suprathermal electrons.

Key words. Ionosphere (electric fields and currents; solar radiation and cosmic ray effects

Effect of suprathermal electrons on the intensity and Doppler frequency of electron plasma lines

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P. Guio

1999-07-01

Full Text Available In an incoherent scattering radar experiment, the spectral measurement of the so-called up- and downshifted electron plasma lines provides information about their intensity and their Doppler frequency. These two spectral lines correspond, in the backscatter geometry, to two Langmuir waves travelling towards and away from the radar. In the daytime ionosphere, the presence of a small percentage of photoelectrons produced by the solar EUV of the total electron population can excite or damp these Langmuir waves above the thermal equilibrium, resulting in an enhancement of the intensity of the lines above the thermal level. The presence of photo-electrons also modifies the dielectric response function of the plasma from the Maxwellian and thus influences the Doppler frequency of the plasma lines. In this paper, we present a high time-resolution plasma-line data set collected on the Eiscat VHF radar. The analysed data are compared with a model that includes the effect of a suprathermal electron population calculated by a transport code. By comparing the intensity of the analysed plasma lines data to our model, we show that two sharp peaks in the electron suprathermal distribution in the energy range 20-30 eV causes an increased Landau damping around 24.25 eV and 26.25 eV. We have identified these two sharp peaks as the effect of the photoionisation of N2 and O by the intense flux of monochromatic HeII radiation of wavelength 30.378 nm (40.812 eV created in the chromospheric network and coronal holes. Furthermore, we see that what would have been interpreted as a mean Doppler drift velocity for a Maxwellian plasma is actually a shift of the Doppler frequency of the plasma lines due to suprathermal electrons.Key words. Ionosphere (electric fields and currents; solar radiation and cosmic ray effects

Doppler evaluation of valvular stenosis

International Nuclear Information System (INIS)

Kisslo, J.; Krafchek, J.; Adams, D.; Mark, D.B.

1986-01-01

One of the reasons why use of Doppler echocardiography is growing rapidly is because of its utility in detecting the presence of valvular stenosis and in estimating its severity. Detection of the presence of stenotic valvular heart disease using Doppler echocardiography was originally described over 10 years ago. It has been demonstrated that Doppler blood velocity data could be used to estimate the severity of a stenotic lesion. This chapter discusses the evaluation of valvular stenois using Doppler

Clinical significance of neonatal parafrontal horn cysts detected by cranial sonography

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Woo, Jeong Joo [Eulji University of Medicine, Daejeon (Korea, Republic of); Jung, Myung Ja [Sanggye Paik Hospital, Inje University of Medicine, Seoul (Korea, Republic of); Kim, Eun Ryung [Sungae General Hospital, Seoul (Korea, Republic of)

2005-07-15

The describe the significance, incidence and characteristics of sonographic findings and long term outcomes of parafrontal horn cysts detected by screening cranial sonography done within the first week following birth. 2122 first cranial ultrasound scans performed over a five year period were retrospectively evaluated and 23 neonates with parafrontal horn cysts were found (which are different from secondary cystic lesions). 17 cases had a birth weight of < 2400 gm with gestation between 30 and 35 weeks, 6 cases had a birth weight of > 2400 gm with gestation between 34 and 41 weeks. The size, shape and location of the parafrontal horn cysts and other associated abnormalities shown on the cranial sonogram were evaluated and sequential ultrasound study, maternal records, neonatal events and neurodevelopmental evaluations were retrospectively assessed. Of the 23 subjects, 21 had isolated parafrontal horn cysts and 2 had subependymal hemorrhages. There was no record of any abnormal perinatal history. The cysts were bilateral in 20 neonates and unilateral in the others. The size of the cysts ranged from 3 to 18 mm in diameter (mean 9 mm). Sonographic features of the parafrontal horn cysts were distinctive morphology (elliptical, thin walled) and location (adjacent to the tip of the frontal horn). In 17 of the cases a follow-up cranial sonography was performed, and all parafrontal horn cysts disappeared within 3 to 6 months. Neurodevelopmental outcomes were normal in those 17 cases. Screening cranial sonography of neonates discovers isolated parafrontal horn cyst. The incidence of parafrontal horn cysts in neonates in our study was 1.1%. They are present in the first week following birth and resolve themselves without medical treatment within a few months. In addition, they show normal neurodevelopment. The parafrontal cysts are suspected to be a benign variant of normal neurodevelopment.

Continuous-variable Einstein-Podolsky-Rosen paradox with traveling-wave second-harmonic generation

International Nuclear Information System (INIS)

Olsen, M.K.

2004-01-01

The Einstein-Podolsky-Rosen paradox and quantum entanglement are at the heart of quantum mechanics. Here we show that single-pass traveling-wave second-harmonic generation can be used to demonstrate both entanglement and the paradox with continuous variables that are analogous to the position and momentum of the original proposal

The Cognitive Doppler.

Science.gov (United States)

Kozoil, Micah E.

1989-01-01

Discusses the learning needs of students in the concrete operational stage in mathematics. Identifies the phenomenon of reduced cognitive performance in an out-of-class environment as the "Cognitive Doppler." Suggests methods of reducing the pronounced effects of the Cognitive Doppler by capitalizing on the students' ability to memorize…

Combined Use of Ultrasound Elastography and B-Mode Sonography for Differentiation of Benign and Malignant Circumscribed Breast Masses.

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Kim, Soo-Yeon; Park, Jeong Seon; Koo, Hye Ryoung

2015-11-01

To evaluate the diagnostic performance of combined B-mode sonography and ultrasound elastography for differentiation between benign and malignant breast masses with circumscribed margins. We analyzed 109 pathologically proven circumscribed breast masses. Two radiologists retrospectively reviewed B-mode sonograms and elastograms in consensus. Based on the American College of Radiology Breast Imaging Reporting and Data System, we determined categories of the masses on B-mode sonography. Elastographic scores were assessed by a 3-point scale (negative, 0; equivocal, 1; and positive, 2). When the elastographic score for a lesion was 0 or 2, we downgraded or upgraded the B-mode category, respectively; thus, the reclassified Breast Imaging Reporting and Data System category was defined as the "reclassification category." Mean category values for benign and malignant lesions were compared by a Student t test. The diagnostic performance of B-mode, elastographic, and reclassification assessments was compared by receiver operating characteristic curve analysis. The mean B-mode category (2.5 versus 1.7), elastographic score (1.7 versus 0.8), and reclassification category (3.2 versus 1.6) were significantly higher in malignant than benign lesions (P benign and malignant circumscribed breast masses, combined use of B-mode sonography and elastography could provide a better diagnostic performance than B-mode sonography alone. © 2015 by the American Institute of Ultrasound in Medicine.

270 nm Pseudomorphic Ultraviolet Light-Emitting Diodes with Over 60 mW Continuous Wave Output Power

Science.gov (United States)

Grandusky, James R.; Chen, Jianfeng; Gibb, Shawn R.; Mendrick, Mark C.; Moe, Craig G.; Rodak, Lee; Garrett, Gregory A.; Wraback, Michael; Schowalter, Leo J.

2013-03-01

In this letter, the achievement of over 60 mW output power from pseudomorphic ultraviolet light-emitting diodes in continuous wave operation is reported. Die thinning and encapsulation improved the photon extraction efficiency to over 15%. Improved thermal management and a high characteristic temperature resulted in a low thermal rolloff up to 300 mA injection current with an output power of 67 mW, an external quantum efficiency (EQE) of 4.9%, and a wall plug efficiency (WPE) of 2.5% for a single-chip device emitting at 271 nm in continuous wave operation.

Doppler ultrasound exam of an arm or leg

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Peripheral vascular disease - Doppler; PVD - Doppler; PAD - Doppler; Blockage of leg arteries - Doppler; Intermittent claudication - Doppler; Arterial insufficiency of the legs - Doppler; Leg pain and ...