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Sample records for doppler ultrasound scan

  1. Long-term effects of in utero Doppler ultrasound scanning--a developmental programming perspective.

    PubMed

    Aiken, C E; Lees, C C

    2012-04-01

    Ultrasound scanning has been used as a diagnostic and screening tool in obstetric practice for over 50 years. There is no evidence of immediate or long-term harm to the developing fetus from exposure to B mode ultrasound. However, exposure to high levels of Doppler ultrasound during early development is increasingly common, and the full safety implications of this exposure are not clear. Doppler ultrasound exposure in utero gives rise to increased apoptosis in animal models, and there is evidence of the effects of exposure to Doppler ultrasound persisting throughout life, with increased non-right-handedness observed in human epidemiological studies. We consider the idea that there may be long-term developmental implications for fetuses exposed to Doppler ultrasound early in gestation. These effects may be mediated via thermal or mechanical disruption to the developing conceptus, giving rise to free radical damage. Excess free radical exposure early in gestation is a strong candidate for the final common pathway underlying developmental programming effects, and gives rise to concern that fetuses exposed to high levels of ultrasound are at risk of a developmental programming effect. It is suggested that there is a need for animal studies of developmental programming using exposure to Doppler ultrasound scanning as the exposure of interest, and for more observational data to be collected in the clinical setting. While these data are collected, it seems prudent to continue to adhere to the principle of 'as low as reasonably achievable' (ALARA) when exposing first-trimester fetuses to Doppler ultrasound. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Doppler ultrasound monitoring technology.

    PubMed

    Docker, M F

    1993-03-01

    Developments in the signal processing of Doppler ultrasound used for the detection of fetal heart rate (FHR) have improved the operation of cardiotocographs. These developments are reviewed and the advantages and disadvantages of the various Doppler and signal processing methods are compared.

  3. Clinical applications of doppler ultrasound

    SciTech Connect

    Taylor, K.J.W.; Burns, P.N.; Well, P.N.T.

    1987-01-01

    This book introduces a guide to the physical principles and instrumentation of duplex Doppler ultrasound and its applications in obstetrics, gynecology, neonatology, gastroentology, and evaluation of peripheral vascular disease. The book provides information needed to perform Doppler ultrasound examinations and interpret the results. An introduction to Doppler physics and instrumentation is followed by a thorough review of hemodynamics, which explains the principles underlying interpretation of Doppler signals. Of special note is the state-of-the-art coverage of new applications of Doppler in recognition of high-risk pregnancy, diagnosis of intrauterine growth retardation, investigation of neonatal blood flow, evaluation of first-trimester pregnancy, and diagnosis of gastrointestinal disease. The book also offers guidelines on the use of Doppler ultrasound in diagnosing carotid disease, deep venous thrombosis, and aorta/femoral disease.

  4. Doppler Ultrasound: What Is It Used for?

    MedlinePlus

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

  5. Doppler ultrasound evaluation in preeclampsia

    PubMed Central

    2013-01-01

    Background Worldwide preeclampsia (PE) is the leading cause of maternal death and affects 5 to 8% of pregnant women. PE is characterized by elevated blood pressure and proteinuria. Doppler Ultrasound (US) evaluation has been considered a useful method for prediction of PE; however, there is no complete data about the most frequently altered US parameters in the pathology. The aim of this study was to evaluate the uterine, umbilical, and the middle cerebral arteries using Doppler US parameters [resistance index (RI), pulsatility index (PI), notch (N), systolic peak (SP) and their combinations] in pregnant women, in order to make a global evaluation of hemodynamic repercussion caused by the established PE. Results A total of 102 pregnant Mexican women (65 PE women and 37 normotensive women) were recruited in a cases and controls study. Blood velocity waveforms from uterine, umbilical, and middle cerebral arteries, in pregnancies from 24 to 37 weeks of gestation were recorded by trans-abdominal examination with a Toshiba Ultrasound Power Vision 6000 SSA-370A, with a 3.5 MHz convex transducer. Abnormal general Doppler US profile showed a positive association with PE [odds ratio (OR) = 2.93, 95% confidence interval (CI) = 1.2 - 7.3, P = 0.021)], and a specificity and predictive positive value of 89.2% and 88.6%, respectively. Other parameters like N presence, RI and PI of umbilical artery, as well as the PI of middle cerebral artery, showed differences between groups (P values < 0.05). Conclusion General Doppler US result, as well as N from uterine vessel, RI from umbilical artery, and PI from umbilical and middle cerebral arteries in their individual form, may be considered as tools to determine hemodynamic repercussion caused by PE. PMID:24252303

  6. Doppler ultrasound evaluation in preeclampsia.

    PubMed

    Lopez-Mendez, Maria A; Martinez-Gaytan, Victoria; Cortes-Flores, Raul; Ramos-Gonzalez, Rene M; Ochoa-Torres, Mauro A; Garza-Veloz, Idalia; Martinez-Acuña, Monica I; Badillo-Almaraz, Jose I; Martinez-Fierro, Margarita L

    2013-11-19

    Worldwide preeclampsia (PE) is the leading cause of maternal death and affects 5 to 8% of pregnant women. PE is characterized by elevated blood pressure and proteinuria. Doppler Ultrasound (US) evaluation has been considered a useful method for prediction of PE; however, there is no complete data about the most frequently altered US parameters in the pathology. The aim of this study was to evaluate the uterine, umbilical, and the middle cerebral arteries using Doppler US parameters [resistance index (RI), pulsatility index (PI), notch (N), systolic peak (SP) and their combinations] in pregnant women, in order to make a global evaluation of hemodynamic repercussion caused by the established PE. A total of 102 pregnant Mexican women (65 PE women and 37 normotensive women) were recruited in a cases and controls study. Blood velocity waveforms from uterine, umbilical, and middle cerebral arteries, in pregnancies from 24 to 37 weeks of gestation were recorded by trans-abdominal examination with a Toshiba Ultrasound Power Vision 6000 SSA-370A, with a 3.5 MHz convex transducer. Abnormal general Doppler US profile showed a positive association with PE [odds ratio (OR) = 2.93, 95% confidence interval (CI) = 1.2 - 7.3, P = 0.021)], and a specificity and predictive positive value of 89.2% and 88.6%, respectively. Other parameters like N presence, RI and PI of umbilical artery, as well as the PI of middle cerebral artery, showed differences between groups (P values < 0.05). General Doppler US result, as well as N from uterine vessel, RI from umbilical artery, and PI from umbilical and middle cerebral arteries in their individual form, may be considered as tools to determine hemodynamic repercussion caused by PE.

  7. ICV Echo Ultrasound Scan

    NASA Image and Video Library

    2012-12-31

    View of Integrated Cardiovascular (ICV) Echo Ultrasound Scan,in the Columbus module. ICV aims to quantify the extent,time course and clinical significance of cardiac atrophy (decrease in the size of the heart muscle) in space. Photo was taken during Expedition 34.

  8. Real-time virtual Doppler ultrasound

    NASA Astrophysics Data System (ADS)

    Khoshniat, Mahdieh; Thorne, Meghan L.; Poepping, Tamie L.; Holdsworth, David W.; Steinman, David A.

    2004-04-01

    Doppler ultrasound (DUS) is widely used to diagnose and plan treatments for vascular diseases, but the relationship between complex blood flow dynamics and the observed DUS signal is not completely understood. In this paper, we demonstrate that Doppler ultrasound can be realistically simulated in a real-time manner via the coupling of a known, previously computed velocity field with a simple model of the ultrasound physics. In the present case a 3D computational fluid dynamics (CFD) model of physiologically pulsatile flow a stenosed carotid bifurcation was interrogated using a sample volume of known geometry and power distribution. Velocity vectors at points within the sample volume were interpolated using a fast geometric search algorithm and, using the specified US probe characteristics and orientation, converted into Doppler shifts for subsequent display as a Doppler spectrogram or color DUS image. The important effect of the intrinsic spectral broadening was simulated by convolving the velocity at each point within the sample volume by a triangle function whose width was proportional to velocity. A spherical sample volume with a Gaussian power distribution was found to be adequate for producing realistic Doppler spectrogram in regions of uniform, jet, and recirculation flow. Fewer than 1000 points seeded uniformly within a radius comprising more than 99% of the total power were required, allowing spectra to be generated from high resolution CFD data at 100Hz frame rates on an inexpensive desktop workstation.

  9. MP3 compression of Doppler ultrasound signals.

    PubMed

    Poepping, Tamie L; Gill, Jeremy; Fenster, Aaron; Holdsworth, David W

    2003-01-01

    The effect of lossy, MP3 compression on spectral parameters derived from Doppler ultrasound (US) signals was investigated. Compression was tested on signals acquired from two sources: 1. phase quadrature and 2. stereo audio directional output. A total of 11, 10-s acquisitions of Doppler US signal were collected from each source at three sites in a flow phantom. Doppler signals were digitized at 44.1 kHz and compressed using four grades of MP3 compression (in kilobits per second, kbps; compression ratios in brackets): 1400 kbps (uncompressed), 128 kbps (11:1), 64 kbps (22:1) and 32 kbps (44:1). Doppler spectra were characterized by peak velocity, mean velocity, spectral width, integrated power and ratio of spectral power between negative and positive velocities. The results suggest that MP3 compression on digital Doppler US signals is feasible at 128 kbps, with a resulting 11:1 compression ratio, without compromising clinically relevant information. Higher compression ratios led to significant differences for both signal sources when compared with the uncompressed signals. Copyright 2003 World Federation for Ultrasound in Medicine & Biology

  10. Applications of Doppler ultrasound in clinical vascular disease

    NASA Technical Reports Server (NTRS)

    Barnes, R. W.; Hokanson, D. E.; Sumner, D. S.; Strandness, D. E., Jr.

    1975-01-01

    Doppler ultrasound has become the most useful and versatile noninvasive technique for objective evaluation of clinical vascular disease. Commercially available continuous-wave instruments provide qualitative and quantitative assessment of venous and arterial disease. Pulsed Doppler ultrasound was developed to provide longitudinal and transverse cross-sectional images of the arterial lumen with a resolution approaching that of conventional X-ray techniques. Application of Doppler ultrasound in venous, peripheral arterial, and cerebrovascular diseases is reviewed.

  11. Applications of Doppler ultrasound in clinical vascular disease

    NASA Technical Reports Server (NTRS)

    Barnes, R. W.; Hokanson, D. E.; Sumner, D. S.; Strandness, D. E., Jr.

    1975-01-01

    Doppler ultrasound has become the most useful and versatile noninvasive technique for objective evaluation of clinical vascular disease. Commercially available continuous-wave instruments provide qualitative and quantitative assessment of venous and arterial disease. Pulsed Doppler ultrasound was developed to provide longitudinal and transverse cross-sectional images of the arterial lumen with a resolution approaching that of conventional X-ray techniques. Application of Doppler ultrasound in venous, peripheral arterial, and cerebrovascular diseases is reviewed.

  12. Superharmonic microbubble Doppler effect in ultrasound therapy

    NASA Astrophysics Data System (ADS)

    Pouliopoulos, Antonios N.; Choi, James J.

    2016-08-01

    The introduction of microbubbles in focused ultrasound therapies has enabled a diverse range of non-invasive technologies: sonoporation to deliver drugs into cells, sonothrombolysis to dissolve blood clots, and blood-brain barrier opening to deliver drugs into the brain. Current methods for passively monitoring the microbubble dynamics responsible for these therapeutic effects can identify the cavitation position by passive acoustic mapping and cavitation mode by spectral analysis. Here, we introduce a new feature that can be monitored: microbubble effective velocity. Previous studies have shown that echoes from short imaging pulses had a Doppler shift that was produced by the movement of microbubbles. Therapeutic pulses are longer (>1 000 cycles) and thus produce a larger alteration of microbubble distribution due to primary and secondary acoustic radiation force effects which cannot be monitored using pulse-echo techniques. In our experiments, we captured and analyzed the Doppler shift during long therapeutic pulses using a passive cavitation detector. A population of microbubbles (5  ×  104-5  ×  107 microbubbles ml-1) was embedded in a vessel (inner diameter: 4 mm) and sonicated using a 0.5 MHz focused ultrasound transducer (peak-rarefactional pressure: 75-366 kPa, pulse length: 50 000 cycles or 100 ms) within a water tank. Microbubble acoustic emissions were captured with a coaxially aligned 7.5 MHz passive cavitation detector and spectrally analyzed to measure the Doppler shift for multiple harmonics above the 10th harmonic (i.e. superharmonics). A Doppler shift was observed on the order of tens of kHz with respect to the primary superharmonic peak and is due to the axial movement of the microbubbles. The position, amplitude and width of the Doppler peaks depended on the acoustic pressure and the microbubble concentration. Higher pressures increased the effective velocity of the microbubbles up to 3 m s-1, prior to the onset of

  13. Superharmonic microbubble Doppler effect in ultrasound therapy.

    PubMed

    Pouliopoulos, Antonios N; Choi, James J

    2016-08-21

    The introduction of microbubbles in focused ultrasound therapies has enabled a diverse range of non-invasive technologies: sonoporation to deliver drugs into cells, sonothrombolysis to dissolve blood clots, and blood-brain barrier opening to deliver drugs into the brain. Current methods for passively monitoring the microbubble dynamics responsible for these therapeutic effects can identify the cavitation position by passive acoustic mapping and cavitation mode by spectral analysis. Here, we introduce a new feature that can be monitored: microbubble effective velocity. Previous studies have shown that echoes from short imaging pulses had a Doppler shift that was produced by the movement of microbubbles. Therapeutic pulses are longer (>1 000 cycles) and thus produce a larger alteration of microbubble distribution due to primary and secondary acoustic radiation force effects which cannot be monitored using pulse-echo techniques. In our experiments, we captured and analyzed the Doppler shift during long therapeutic pulses using a passive cavitation detector. A population of microbubbles (5  ×  10(4)-5  ×  10(7) microbubbles ml(-1)) was embedded in a vessel (inner diameter: 4 mm) and sonicated using a 0.5 MHz focused ultrasound transducer (peak-rarefactional pressure: 75-366 kPa, pulse length: 50 000 cycles or 100 ms) within a water tank. Microbubble acoustic emissions were captured with a coaxially aligned 7.5 MHz passive cavitation detector and spectrally analyzed to measure the Doppler shift for multiple harmonics above the 10th harmonic (i.e. superharmonics). A Doppler shift was observed on the order of tens of kHz with respect to the primary superharmonic peak and is due to the axial movement of the microbubbles. The position, amplitude and width of the Doppler peaks depended on the acoustic pressure and the microbubble concentration. Higher pressures increased the effective velocity of the microbubbles up to 3 m s(-1), prior to the onset

  14. Superharmonic microbubble Doppler effect in ultrasound therapy

    PubMed Central

    Pouliopoulos, Antonios N; Choi, James J

    2016-01-01

    Abstract The introduction of microbubbles in focused ultrasound therapies has enabled a diverse range of non-invasive technologies: sonoporation to deliver drugs into cells, sonothrombolysis to dissolve blood clots, and blood-brain barrier opening to deliver drugs into the brain. Current methods for passively monitoring the microbubble dynamics responsible for these therapeutic effects can identify the cavitation position by passive acoustic mapping and cavitation mode by spectral analysis. Here, we introduce a new feature that can be monitored: microbubble effective velocity. Previous studies have shown that echoes from short imaging pulses had a Doppler shift that was produced by the movement of microbubbles. Therapeutic pulses are longer (>1 000 cycles) and thus produce a larger alteration of microbubble distribution due to primary and secondary acoustic radiation force effects which cannot be monitored using pulse-echo techniques. In our experiments, we captured and analyzed the Doppler shift during long therapeutic pulses using a passive cavitation detector. A population of microbubbles (5  ×  104–5  ×  107 microbubbles ml−1) was embedded in a vessel (inner diameter: 4 mm) and sonicated using a 0.5 MHz focused ultrasound transducer (peak-rarefactional pressure: 75–366 kPa, pulse length: 50 000 cycles or 100 ms) within a water tank. Microbubble acoustic emissions were captured with a coaxially aligned 7.5 MHz passive cavitation detector and spectrally analyzed to measure the Doppler shift for multiple harmonics above the 10th harmonic (i.e. superharmonics). A Doppler shift was observed on the order of tens of kHz with respect to the primary superharmonic peak and is due to the axial movement of the microbubbles. The position, amplitude and width of the Doppler peaks depended on the acoustic pressure and the microbubble concentration. Higher pressures increased the effective velocity of the microbubbles up to 3 m s−1, prior to

  15. Adaptive Spectral Envelope Estimation for Doppler Ultrasound.

    PubMed

    Kathpalia, Aditi; Karabiyik, Yucel; Eik-Nes, Sturla; Tegnander, Eva; Ekroll, Ingvild; Kiss, Gabriel; Torp, Hans

    2016-07-07

    Estimation of accurate maximum velocities and spectral envelope in ultrasound Doppler blood flow spectrograms are both essential for clinical diagnostic purposes. However, obtaining accurate maximum velocity is not straightforward due to intrinsic spectral broadening and variance in the power spectrum estimate. The method proposed in this work for maximum velocity point detection has been developed by modifying an existing method - Signal Noise Slope Intersection (SNSI), incorporating in it steps from an altered version of another method called Geometric Method (GM). Adaptive noise estimation from the spectrogram ensures that a smooth spectral envelope is obtained post detection of these maximum velocity points. The method has been tested on simulated Doppler signal with scatterers possessing a parabolic flow velocity profile constant in time, steady and pulsatile string phantom recordings as well as in vivo recordings from uterine, umbilical, carotid and subclavian arteries. Results from simulation experiments indicate a bias of less than 2.5% in maximum velocities when estimated for a range of peak velocities, Doppler angles and SNR levels. Standard deviation in the envelope is low - less than 2% in case of experiments done by varying the peak velocity and Doppler angle for steady phantom and simulated flow; and also less than 2% in case of experiments done by varying SNR but keeping constant flow conditions for in vivo and simulated flow. Low variability in the envelope makes the prospect of using the envelope for automated blood flow measurements possible and is illustrated for the case of Pulsatility Index estimation in uterine and umbilical arteries.

  16. Intraluminal ultrasound intensity distribution and backscattered Doppler power.

    PubMed

    Thompson, Rosemary S; Bambi, Giacomo; Steel, Robin; Tortoli, Piero

    2004-11-01

    Ultrasound (US) incident obliquely on a cylindrical vessel is redistributed in space when the propagation path includes walls with acoustic impedance different from that of the surrounding media. We investigated this using low-density polyethylene (PE) as the vessel wall material. Both simulations and experiments were carried out. Direct hydrophone measurements of the acoustic field were made within a half section of the PE tube, and the distribution of backscattered Doppler power along a scan line was obtained using a range-Doppler instrument. Both simulation and hydrophone results demonstrate lateral shadow regions within the lumen. In every one of various Doppler flow experiments conducted, the backscattered Doppler power, compensated for on-axis transducer behaviour, increased with depth. Simulation results for an incident continuous-wave (CW) plane wave show that it tends to be focused by the curvature of the PE tube walls. The wall interactions are, however, angle-dependent and so the behaviour of a focused US beam depends on the beam as well as the walls. This study demonstrates alterations in the spatial distribution of US within a cylindrical vessel as a result of known vessel wall properties. It also provides evidence that local intensity variations within the lumen affect the relative Doppler power backscattered from small sample volumes.

  17. Breast ultrasound scans - surgeons' expectations.

    PubMed

    Bednarski, Piotr; Dobruch-Sobczak, Katarzyna; Chrapowicki, Eryk; Jakubowski, Wiesław

    2015-06-01

    Recent years have witnessed a dynamic development of mammary gland imaging techniques, particularly ultrasonography and magnetic resonance imaging. A challenge related to these studies is the increase in the precision of the anatomical assessment of breast, particularly for early detection of subclinical lesions, performance of ultrasound- guided biopsy procedures, and accurate preoperative location of pathological lesions so as to optimize the surgical treatment. Ultrasound imaging is a primary and baseline diagnostic procedure the patient with suspected pathological lesions within breast is referred to by the surgeon. Lesions visualized in ultrasound scans are classified according to the BI-RADS US assessment categories. The successive categories (2 through 6) encompass individual pathological lesions, estimating the risk of malignancy and provide guidelines for further diagnostic and therapeutic management. This article described the important aspects of ultrasonographic imaging of focal lesions within the breasts as significant from the standpoint of surgical treatment of patients falling within BI-RADS US categories 3, 4, 5, and 6. Attention is drawn to the importance of ultrasound scans in the assessment of axillary fossa lymph nodes before the decision regarding the surgical treatment.

  18. Adaptive Spectral Envelope Estimation for Doppler Ultrasound.

    PubMed

    Kathpalia, Aditi; Karabiyik, Yucel; Eik-Nes, Sturla H; Tegnander, Eva; Ekroll, Ingvild Kinn; Kiss, Gabriel; Torp, Hans

    2016-11-01

    Estimation of accurate maximum velocities and spectral envelope in ultrasound Doppler blood flow spectrograms are both essential for clinical diagnostic purposes. However, obtaining accurate maximum velocity is not straightforward due to intrinsic spectral broadening and variance in the power spectrum estimate. The method proposed in this paper for maximum velocity point detection has been developed by modifying an existing method-signal noise slope intersection, incorporating in it steps from an altered version of another method called geometric method. Adaptive noise estimation from the spectrogram ensures that a smooth spectral envelope is obtained postdetection of these maximum velocity points. The method has been tested on simulated Doppler signal with scatterers possessing a parabolic flow velocity profile constant in time, steady and pulsatile string phantom recordings, as well as in vivo recordings from uterine, umbilical, carotid, and subclavian arteries. The results from simulation experiments indicate a bias of less than 2.5% in maximum velocities when estimated for a range of peak velocities, Doppler angles, and SNR levels. Standard deviation in the envelope is low-less than 2% in the case of experiments done by varying the peak velocity and Doppler angle for steady phantom and simulated flow, and also less than 2% in the case of experiments done by varying SNR but keeping constant flow conditions for in vivo and simulated flow. Low variability in the envelope makes the prospect of using the envelope for automated blood flow measurements possible and is illustrated for the case of pulsatility index estimation in uterine and umbilical arteries.

  19. Power and color Doppler ultrasound settings for inflammatory flow: impact on scoring of disease activity in patients with rheumatoid arthritis.

    PubMed

    Torp-Pedersen, Søren; Christensen, Robin; Szkudlarek, Marcin; Ellegaard, Karen; D'Agostino, Maria Antonietta; Iagnocco, Annamaria; Naredo, Esperanza; Balint, Peter; Wakefield, Richard J; Torp-Pedersen, Arendse; Terslev, Lene

    2015-02-01

    To determine how settings for power and color Doppler ultrasound sensitivity vary on different high- and intermediate-range ultrasound machines and to evaluate the impact of these changes on Doppler scoring of inflamed joints. Six different types of ultrasound machines were used. On each machine, the factory setting for superficial musculoskeletal scanning was used unchanged for both color and power Doppler modalities. The settings were then adjusted for increased Doppler sensitivity, and these settings were designated study settings. Eleven patients with rheumatoid arthritis (RA) with wrist involvement were scanned on the 6 machines, each with 4 settings, generating 264 Doppler images for scoring and color quantification. Doppler sensitivity was measured with a quantitative assessment of Doppler activity: color fraction. Higher color fraction indicated higher sensitivity. Power Doppler was more sensitive on half of the machines, whereas color Doppler was more sensitive on the other half, using both factory settings and study settings. There was an average increase in Doppler sensitivity, despite modality, of 78% when study settings were applied. Over the 6 machines, 2 Doppler modalities, and 2 settings, the grades for each of 7 of the patients varied between 0 and 3, while the grades for each of the other 4 patients varied between 0 and 2. The effect of using different machines, Doppler modalities, and settings has a considerable influence on the quantification of inflammation by ultrasound in RA patients, and this must be taken into account in multicenter studies. Copyright © 2015 by the American College of Rheumatology.

  20. Measurement of the Doppler power of flowing blood using ultrasound Doppler devices.

    PubMed

    Huang, Chih-Chung; Chou, Hung-Lung; Chen, Pay-Yu

    2015-02-01

    Measurement of the Doppler power of signals backscattered from flowing blood (henceforth referred to as the Doppler power of flowing blood) and the echogenicity of flowing blood have been used widely to assess the degree of red blood cell (RBC) aggregation for more than 20 y. Many studies have used Doppler flowmeters based on an analogue circuit design to obtain the Doppler shifts in the signals backscattered from flowing blood; however, some recent studies have mentioned that the analogue Doppler flowmeter exhibits a frequency-response problem whereby the backscattered energy is lost at higher Doppler shift frequencies. Therefore, the measured Doppler power of flowing blood and evaluations of RBC aggregation obtained using an analogue Doppler device may be inaccurate. To overcome this problem, the present study implemented a field-programmable gate array-based digital pulsed-wave Doppler flowmeter to measure the Doppler power of flowing blood, in the aim of providing more accurate assessments of RBC aggregation. A clinical duplex ultrasound imaging system that can acquire pulsed-wave Doppler spectrograms is now available, but its usefulness for estimating the ultrasound scattering properties of blood is still in doubt. Therefore, the echogenicity and Doppler power of flowing blood under the same flow conditions were measured using a laboratory pulser-receiver system and a clinical ultrasound system, respectively, for comparisons. The experiments were carried out using porcine blood under steady laminar flow with both RBC suspensions and whole blood. The experimental results indicated that a clinical ultrasound system used to measure the Doppler spectrograms is not suitable for quantifying Doppler power. However, the Doppler power measured using a digital Doppler flowmeter can reveal the relationship between backscattering signals and the properties of blood cells because the effects of frequency response are eliminated. The measurements of the Doppler power and

  1. Ultrasound imaging for the rheumatologist. XVII. Role of colour Doppler and power Doppler.

    PubMed

    Iagnocco, A; Epis, O; Delle Sedie, A; Meenagh, G; Filippucci, E; Riente, L; Scirè, C A; Montecucco, C; Bombardieri, S; Grassi, W; Valesini, G

    2008-01-01

    The use of Doppler ultrasound in rheumatology has grown in recent years. This is partly due to the increasing number of rheumatologists who perform US in their daily clinical practise and also to the technological advances of US systems. Both colour Doppler and power Doppler are used to evaluate the degree of intra- and peri-articular soft tissue inflammation. Moreover, Doppler US has been found to be of help in the assessment of vascular pathologies such as the vasculitides. In this review we provide an update of the data regarding the use of colour Doppler and power Doppler in rheumatology.

  2. Doppler ultrasound imaging for detection of deep vein thrombosis in plastic surgery outpatients: a prospective controlled study.

    PubMed

    Swanson, Eric

    2015-02-01

    Venous thromboembolism is a serious surgical complication. Risk stratification does not reliably predict which patients will be affected, and anticoagulants introduce additional risks. The Doppler ultrasound scan is the definitive test for the detection of deep vein thrombosis. This prospective, controlled study was undertaken to determine the feasibility of Doppler ultrasound imaging as a screening tool for deep vein thromboses in plastic surgery outpatients. Doppler ultrasound screening was offered to 100 consecutive outpatients undergoing a variety of cosmetic plastic surgeries. Total intravenous anesthesia was administered by propofol infusion, and a laryngeal mask airway was inserted. SAFE (spontaneous breathing, avoid gas, face up, and extremities mobile) principles were observed. No patient received anticoagulants. Ultrasound scans were performed before surgery, 1 day after surgery, and approximately 1 week after surgery. Deep veins of the lower extremities, including the calf veins, were analyzed by compression, color Doppler imaging, and Doppler waveform analyses. Twenty-five control participants who did not undergo surgery were evaluated with ultrasonography. A survey was administered to all participants after the scans. No thromboses were detected in the outpatient or control group. Few survey respondents reported discomfort during the scan, and most indicated that ultrasound scans are a valuable screening tool for blood clots. Doppler ultrasound imaging of the lower extremities is a valuable, noninvasive method for detecting deep venous thromboses in plastic surgery outpatients. Additional study of this modality is warranted. LEVEL OF EVIDENCE 2: Diagnostic. © 2015 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

  3. Is Doppler ultrasound useful for evaluating gestational trophoblastic disease?

    PubMed

    Lin, Lawrence H; Bernardes, Lisandra S; Hase, Eliane A; Fushida, Koji; Francisco, Rossana P V

    2015-12-01

    Doppler ultrasound is a non-invasive method for evaluating vascularization and is widely used in clinical practice. Gestational trophoblastic neoplasia includes a group of highly vascularized malignancies derived from placental cells. This review summarizes data found in the literature regarding the applications of Doppler ultrasound in managing patients with gestational trophoblastic neoplasia. The PubMed/Medline, Web of Science, Cochrane and LILACS databases were searched for articles published in English until 2014 using the following keywords: "Gestational trophoblastic disease AND Ultrasonography, Doppler." Twenty-eight articles met the inclusion criteria and were separated into the 4 following groups according to the aim of the study. (1) Doppler ultrasound does not seem to be capable of differentiating partial from complete moles, but it might be useful when evaluating pregnancies in which a complete mole coexists with a normal fetus. (2) There is controversy in the role of uterine artery Doppler velocimetry in the prediction of development of gestational trophoblastic neoplasia. (3) Doppler ultrasound is a useful tool in the diagnosis of gestational trophoblastic neoplasia because abnormal myometrial vascularization and lower uterine artery Doppler indices seem to be correlated with invasive disease. (4) Lower uterine artery Doppler indices in the diagnosis of gestational trophoblastic neoplasia are associated with methotrexate resistance and might play a role in prognosis. Several studies support the importance of Doppler ultrasound in the management of patients with gestational trophoblastic neoplasia, particularly the role of Doppler velocimetry in the prediction of trophoblastic neoplasia and the chemoresistance of trophoblastic tumors. Doppler findings should be used as ancillary tools, along with human chorionic gonadotropin assessment, in the diagnosis of gestational trophoblastic neoplasia.

  4. Is Doppler ultrasound useful for evaluating gestational trophoblastic disease?

    PubMed Central

    Lin, Lawrence H; Bernardes, Lisandra S; Hase, Eliane A; Fushida, Koji; Francisco, Rossana P V

    2015-01-01

    Doppler ultrasound is a non-invasive method for evaluating vascularization and is widely used in clinical practice. Gestational trophoblastic neoplasia includes a group of highly vascularized malignancies derived from placental cells. This review summarizes data found in the literature regarding the applications of Doppler ultrasound in managing patients with gestational trophoblastic neoplasia. The PubMed/Medline, Web of Science, Cochrane and LILACS databases were searched for articles published in English until 2014 using the following keywords: “Gestational trophoblastic disease AND Ultrasonography, Doppler.” Twenty-eight articles met the inclusion criteria and were separated into the 4 following groups according to the aim of the study. 1 Doppler ultrasound does not seem to be capable of differentiating partial from complete moles, but it might be useful when evaluating pregnancies in which a complete mole coexists with a normal fetus. 2 There is controversy in the role of uterine artery Doppler velocimetry in the prediction of development of gestational trophoblastic neoplasia. 3 Doppler ultrasound is a useful tool in the diagnosis of gestational trophoblastic neoplasia because abnormal myometrial vascularization and lower uterine artery Doppler indices seem to be correlated with invasive disease. 4 Lower uterine artery Doppler indices in the diagnosis of gestational trophoblastic neoplasia are associated with methotrexate resistance and might play a role in prognosis. CONCLUSION: Several studies support the importance of Doppler ultrasound in the management of patients with gestational trophoblastic neoplasia, particularly the role of Doppler velocimetry in the prediction of trophoblastic neoplasia and the chemoresistance of trophoblastic tumors. Doppler findings should be used as ancillary tools, along with human chorionic gonadotropin assessment, in the diagnosis of gestational trophoblastic neoplasia. PMID:26735221

  5. Fetal and umbilical Doppler ultrasound in normal pregnancy

    PubMed Central

    Alfirevic, Zarko; Stampalija, Tamara; Gyte, Gillian ML

    2014-01-01

    Background One of the main aims of routine antenatal care is to identify the ‘at risk’ fetus in order to apply clinical interventions which could result in reduced perinatal morbidity and mortality. Doppler ultrasound study of umbilical artery waveforms helps to identify the compromised fetus in ‘high-risk’ pregnancies and, therefore, deserves assessment as a screening test in ‘low-risk’ pregnancies. Objectives To assess the effects on obstetric practice and pregnancy outcome of routine fetal and umbilical Doppler ultrasound in unselected and low-risk pregnancies. Search methods We searched the Cochrane Pregnancy and Childbirth Group Trials Register (May 2010). Selection criteria Randomised and quasi-randomised controlled trials of Doppler ultrasound for the investigation of umbilical and fetal vessels waveforms in unselected pregnancies compared to no Doppler ultrasound. Studies where uterine vessels have been assessed together with fetal and umbilical vessels have been included. Data collection and analysis Two authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. Main results We included five trials involving 14,185 women. The methodological quality of the trials was generally unclear because of insufficient data included in the reports. Routine fetal and umbilical Doppler ultrasound examination in low-risk or unselected populations did not result in increased antenatal, obstetric and neonatal interventions, and no overall differences were detected for substantive short term clinical outcomes such as perinatal mortality. There is no available evidence to assess the effect on substantive long term outcomes such as childhood neurodevelopment and no data to assess maternal outcomes, particularly psychological effects. Authors’ conclusions Existing evidence does not provide conclusive evidence that the use of routine umbilical artery Doppler ultrasound, or combination of umbilical and uterine

  6. The role of tissue harmonic imaging ultrasound combined with power Doppler ultrasound in the diagnosis of childhood febrile urinary tract infections.

    PubMed

    İlarslan, Nisa Eda Çullas; Fitöz, Ömer Suat; Öztuna, Derya Gökmen; Küçük, Nuriye Özlem; Yalçınkaya, Fatma Fatoş

    2015-06-01

    This study assessed the ability of tissue harmonic imaging ultrasound combined with power Doppler ultrasound in the detection of childhood febrile urinary tract infections in comparison with the gold standard reference method: Tc-99m dimercaptosuccinicacid renal cortical scintigraphy. This prospective study included 60 patients who were hospitalized with a first episode of febrile urinary tract infections. All children were examined with dimercaptosuccinicacid scan and tissue harmonic imaging ultrasound combined with power Doppler ultrasound within the first 3 days of admission. Signs indicative of acute infection were observed in 29 patients according to the results of tissue harmonic imaging ultrasound combined with power Doppler ultrasound while dimercaptosuccinicacid scan revealed abnormal findings in 33 patients. The sensitivity, specificity, positive predictive value and negative predictive value of tissue harmonic imaging combined with power Doppler ultrasound using dimercaptosuccinicacid scintigraphy as the reference method in patients diagnosed with first episode febrile urinary tract infections were calculated as 57.58% (95% confidence interval: 40.81%-72.76%); 62.96% (95% confidence interval: 44.23%-78.47%); 65.52% (95% confidence interval: 52.04%-77%); 54.84% (95% confidence interval: 41.54%-67.52%); respectively. Although current results exhibit inadequate success of power Doppler ultrasound, this practical and radiation-free method may soon be comprise a part of the routine ultrasonographic evaluation of febrile urinary tract infections of childhood if patients are evaluated early and under appropriate sedation.

  7. The role of tissue harmonic imaging ultrasound combined with power Doppler ultrasound in the diagnosis of childhood febrile urinary tract infections

    PubMed Central

    İlarslan, Nisa Eda Çullas; Fitöz, Ömer Suat; Öztuna, Derya Gökmen; Küçük, Nuriye Özlem; Yalçınkaya, Fatma Fatoş

    2015-01-01

    Aim: This study assessed the ability of tissue harmonic imaging ultrasound combined with power Doppler ultrasound in the detection of childhood febrile urinary tract infections in comparison with the gold standard reference method: Tc-99m dimercaptosuccinicacid renal cortical scintigraphy. Material and Methods: This prospective study included 60 patients who were hospitalized with a first episode of febrile urinary tract infections. All children were examined with dimercaptosuccinicacid scan and tissue harmonic imaging ultrasound combined with power Doppler ultrasound within the first 3 days of admission. Results: Signs indicative of acute infection were observed in 29 patients according to the results of tissue harmonic imaging ultrasound combined with power Doppler ultrasound while dimercaptosuccinicacid scan revealed abnormal findings in 33 patients. The sensitivity, specificity, positive predictive value and negative predictive value of tissue harmonic imaging combined with power Doppler ultrasound using dimercaptosuccinicacid scintigraphy as the reference method in patients diagnosed with first episode febrile urinary tract infections were calculated as 57.58% (95% confidence interval: 40.81%–72.76%); 62.96% (95% confidence interval: 44.23%–78.47%); 65.52% (95% confidence interval: 52.04%–77%); 54.84% (95% confidence interval: 41.54%–67.52%); respectively. Conclusions: Although current results exhibit inadequate success of power Doppler ultrasound, this practical and radiation-free method may soon be comprise a part of the routine ultrasonographic evaluation of febrile urinary tract infections of childhood if patients are evaluated early and under appropriate sedation. PMID:26265892

  8. Graphics processing unit-based high-frame-rate color Doppler ultrasound processing.

    PubMed

    Chang, Li-Wen; Hsu, Ke-Hsin; Li, Pai-Chi

    2009-09-01

    Color Doppler ultrasound is a routinely used diagnostic tool for assessing blood flow information in real time. The required signal processing is computationally intensive, involving autocorrelation, linear filtering, median filtering, and thresholding. Because of the large amount of data and high computational requirement, color Doppler signal processing has been mainly implemented on custom-designed hardware, with software-based implementation--particularly on a general-purpose CPU--not being successful. In this paper, we describe the use of a graphics processing unit for implementing signal-processing algorithms for color Doppler ultrasound that achieves a frame rate of 160 fps for frames comprising 500 scan lines x 128 range samples, with each scan line being obtained from an ensemble size of 8 with an 8-tap FIR clutter filter.

  9. Automatic segmentation of vessels in in-vivo ultrasound scans

    NASA Astrophysics Data System (ADS)

    Tamimi-Sarnikowski, Philip; Brink-Kjær, Andreas; Moshavegh, Ramin; Arendt Jensen, Jørgen

    2017-03-01

    Ultrasound has become highly popular to monitor atherosclerosis, by scanning the carotid artery. The screening involves measuring the thickness of the vessel wall and diameter of the lumen. An automatic segmentation of the vessel lumen, can enable the determination of lumen diameter. This paper presents a fully automatic segmentation algorithm, for robustly segmenting the vessel lumen in longitudinal B-mode ultrasound images. The automatic segmentation is performed using a combination of B-mode and power Doppler images. The proposed algorithm includes a series of preprocessing steps, and performs a vessel segmentation by use of the marker-controlled watershed transform. The ultrasound images used in the study were acquired using the bk3000 ultrasound scanner (BK Ultrasound, Herlev, Denmark) with two transducers "8L2 Linear" and "10L2w Wide Linear" (BK Ultrasound, Herlev, Denmark). The algorithm was evaluated empirically and applied to a dataset of in-vivo 1770 images recorded from 8 healthy subjects. The segmentation results were compared to manual delineation performed by two experienced users. The results showed a sensitivity and specificity of 90.41+/-11.2 % and 97.93+/-5.7% (mean+/-standard deviation), respectively. The amount of overlap of segmentation and manual segmentation, was measured by the Dice similarity coefficient, which was 91.25+/-11.6%. The empirical results demonstrated the feasibility of segmenting the vessel lumen in ultrasound scans using a fully automatic algorithm.

  10. The leicester Doppler phantom--a digital electronic phantom for ultrasound pulsed Doppler system testing.

    PubMed

    Gittins, John; Martin, Kevin

    2010-04-01

    Doppler flow and string phantoms have been used to assess the performance of ultrasound Doppler systems in terms of parameters such as sensitivity, velocity accuracy and sample volume registration. However, because of the nature of their construction, they cannot challenge the accuracy and repeatability of modern digital ultrasound systems or give objective measures of system performance. Electronic Doppler phantoms are able to make use of electronically generated test signals, which may be controlled precisely in terms of frequency, amplitude and timing. The Leicester Electronic Doppler Phantom uses modern digital signal processing methods and field programmable gate array technology to overcome some of the limitations of previously described electronic phantoms. In its present form, it is able to give quantitative graphical assessments of frequency response and range gate characteristics, as well as measures of dynamic range and velocity measurement accuracy. The use of direct acoustic coupling eliminates uncertainties caused by Doppler beam effects, such as intrinsic spectral broadening, but prevents their evaluation.

  11. Ocular Health (OH) Ultrasound 2 Scan

    NASA Image and Video Library

    2013-06-06

    Astronaut Karen Nyberg,Expedition 37 flight engineer, assisted by astronaut Chris Cassidy, performs an Ocular Health (OH) Ultrasound 2 scan in the Destiny laboratory of the International Space Station.

  12. Is complete umbilical cord scanning possible at the second-trimester ultrasound scan?

    PubMed

    Ugurlucan, Funda Gungor; Yuksel, Atil

    2014-10-01

    To evaluate the feasibility of umbilical cord scanning during the second-trimester sonographic examination, we looked at the method of scanning, the findings, and the time spent. Five hundred forty-nine singleton pregnancies were evaluated at 18-23 weeks' menstrual age with two-dimensional sonography (US). Color Doppler US was used when needed. The umbilical cord was traced from the fetal insertion site to the placental insertion site. Fetal and placental sites of insertion; number of vessels; presence of knots, cysts, tumors, nuchal cords, or placental anomalies; time spent for scanning; and the use of color Doppler US were noted. The mean maternal age was 33.1 ± 4.1 years, and the mean menstrual age of the fetuses during scanning was 20.4 ± 2.4 weeks. The mean time spent for umbilical cord scanning was 41.5 ± 46.7 seconds. In one case (0.2%), the umbilical cord could not be scanned completely. Color Doppler US was needed in 125 (22.8%) of the scans. Scan results were positive in 153 (27.9%) cases. We observed six cases (1.1%) of a single umbilical artery, two (0.4%) umbilical cord knots, one (0.2%) umbilical cord hernia, and 104 (18.9%) nuchal cords. We also documented 27 (5.0%) marginal insertions, four placenta previa totalis (0.7%), four placenta previa marginalis (0.7%), and eight velamentous insertions (1.5%). Umbilical cord US scanning is feasible during the second trimester of pregnancy, and complete scanning can be performed in the majority of the cases. Color Doppler analysis may aid scanning when needed. © 2014 Wiley Periodicals, Inc. J Clin Ultrasound, 2014. Copyright © 2014 Wiley Periodicals, Inc.

  13. Oxygen consumption estimation with combined color doppler ultrasound and photoacoustic microscopy: a phantom study

    NASA Astrophysics Data System (ADS)

    Jiang, Yan; Harrison, Tyler; Forbrich, Alex; Zemp, Roger J.

    2011-03-01

    The metabolic rate of oxygen consumption (MRO2) quantifies tissue metabolism, which is important for diagnosis of many diseases. For a single vessel model, the MRO2 can be estimated in terms of the mean flow velocity, vessel crosssectional area, total concentration of hemoglobin (CHB), and the difference between the oxygen saturation (sO2) of blood flowing into and out of the tissue region. In this work, we would like to show the feasibility to estimate MRO2 with our combined photoacoustic and high-frequency ultrasound imaging system. This system uses a swept-scan 25-MHz ultrasound transducer with confocal dark-field laser illumination optics. A pulse-sequencer enables ultrasonic and laser pulses to be interlaced so that photoacoustic and Doppler ultrasound images are co-registered. Since the mean flow velocity can be measured by color Doppler ultrasound, the vessel cross-sectional area can be measured by power Doppler or photoacoustic imaging, and multi-wavelength photoacoustic methods can be used to estimate sO2 and CHB, all of these parameters necessary for MRO2 estimation can be provided by our system. Experiments have been performed on flow phantoms to generate co-registered color Doppler and photoacoustic images. To verify the sO2 estimation, two ink samples (red and blue) were mixed in various concentration ratios to mimic different levels of sO2, and the result shows a good match between the calculated concentration ratios and actual values.

  14. Pediatric imaging/doppler ultrasound of the chest: Extracardiac diagnosis

    SciTech Connect

    Huhta, J.C.

    1986-01-01

    In this book the author spells out new diagnostic applications in pediatrics for high resolution cross-sectional ultrasonography, and demonstrates the ways in which Doppler techniques complement the cross-sectional method. This reference presents practical, step-by-step methods for non-invasive ultrasound examination of extra-cardiac anatomy and assessment of vascular blood flow.

  15. Utero-placental Doppler ultrasound for improving pregnancy outcome

    PubMed Central

    Stampalija, Tamara; Gyte, Gillian ML; Alfirevic, Zarko

    2014-01-01

    Background Impaired placentation can cause some of the most important obstetrical complications such as pre-eclampsia and intrauterine growth restriction and has been linked to increased fetal morbidity and mortality. The failure to undergo physiological trophoblastic vascular changes is reflected by the high impedance to the blood flow at the level of the uterine arteries. Doppler ultrasound study of utero-placental blood vessels, using waveform indices or notching, may help to identify the ‘at-risk’ women in the first and second trimester of pregnancy, such that interventions might be used to reduce maternal and fetal morbidity and/or mortality. Objectives To assess the effects on pregnancy outcome, and obstetric practice, of routine utero-placental Doppler ultrasound in first and second trimester of pregnancy in pregnant women at high and low risk of hypertensive complications. Search methods We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (June 2010) and the reference lists of identified studies. Selection criteria Randomised and quasi-randomised controlled trials of Doppler ultrasound for the investigation of utero-placental vessel waveforms in first and second trimester compared with no Doppler ultrasound. We have excluded studies where uterine vessels have been assessed together with fetal and umbilical vessels. Data collection and analysis Two authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. We checked data entry. Main results We found two studies involving 4993 participants. The methodological quality of the trials was good. Both studies included women at low risk for hypertensive disorders, with Doppler ultrasound of the uterine arteries performed in the second trimester of pregnancy. In both studies, pathological finding of uterine arteries was followed by low-dose aspirin administration. We identified no difference in short-term maternal and fetal clinical

  16. Fetal and umbilical Doppler ultrasound in high-risk pregnancies

    PubMed Central

    Alfirevic, Zarko; Stampalija, Tamara; Gyte, Gillian ML

    2014-01-01

    Background Abnormal blood flow patterns in fetal circulation detected by Doppler ultrasound may indicate poor fetal prognosis. It is also possible false positive Doppler ultrasound findings could encourage inappropriate early delivery. Objectives The objective of this review was to assess the effects of Doppler ultrasound used to assess fetal well-being in high-risk pregnancies on obstetric care and fetal outcomes. Search methods We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (September 2009) and the reference lists of identified studies. Selection criteria Randomised and quasi-randomised controlled trials of Doppler ultrasound for the investigation of umbilical and fetal vessels waveforms in high-risk pregnancies compared to no Doppler ultrasound. Data collection and analysis Two authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. Data entry was checked. Main results Eighteen completed studies involving just over 10,000 women were included. The trials were generally of unclear quality with some evidence of possible publication bias. The use of Doppler ultrasound in high-risk pregnancy was associated a reduction in perinatal deaths (risk ratio (RR) 0.71, 95% confidence interval (CI) 0.52 to 0.98, 16 studies, 10,225 babies, 1.2% versus 1.7 %, numbers needed to treat = 203; 95%CI 103 to 4352). There were also fewer inductions of labour (average RR 0.89, 95% CI 0.80 to 0.99, 10 studies, 5633 women, random effects) and fewer caesarean sections (RR 0.90, 95% CI 0.84 to 0.97, 14 studies, 7918 women). No difference was found in operative vaginal births (RR 0.95, 95% CI 0.80 to 1.14, four studies, 2813 women) nor in Apgar scores less than seven at five minutes (RR 0.92, 95% CI 0.69 to 1.24, seven studies, 6321 babies). Authors’ conclusions Current evidence suggests that the use of Doppler ultrasound in high-risk pregnancies reduced the risk of perinatal deaths and resulted in less

  17. Simultaneous fetal magnetocardiography and ultrasound/Doppler imaging.

    PubMed

    Zhao, Hui; Chen, Mingli; Van Veen, Barry D; Strasburger, Janette F; Wakai, Ronald T

    2007-06-01

    The difficulty of utilizing multimodality diagnostic imaging techniques for fetal surveillance remains one of the greatest challenges in providing enhanced prenatal care. In this Letter we demonstrate the feasibility of performing fetal magnetocardiography (fMCG) and ultrasound/Doppler imaging simultaneously, using a multichannel SQUID magnetometer and a portable ultrasound scanner. Despite large magnetic interference from the scanner, the implementation of simple noise reduction procedures and appropriate signal processing techniques yielded fMCG recordings of sufficient quality for assessment of fetal heart rate and rhythm. A variation of reference channel filtering, referred to here as synthetic reference channel filtering, was used to reduce nonstationary low-frequency interference. The combination of fMCG and/or fMEG with ultrasound/Doppler offers new possibilities for assessment of fetal well-being and fetal cardiac function.

  18. Robust estimation of fetal heart rate variability using Doppler ultrasound.

    PubMed

    Fernando, Kumari L; Mathews, V John; Varner, Michael W; Clark, Edward B

    2003-08-01

    This paper presents a new measure of heart rate variability (HRV) that can be estimated using Doppler ultrasound techniques and is robust to variations in the angle of incidence of the ultrasound beam and the measurement noise. This measure employs the multiple signal characterization (MUSIC) algorithm which is a high-resolution method for estimating the frequencies of sinusoidal signals embedded in white noise from short-duration measurements. We show that the product of the square-root of the estimated signal-to-noise ratio (SNR) and the mean-square error of the frequency estimates is independent of the noise level in the signal. Since varying angles of incidence effectively changes the input SNR, this measure of HRV is robust to the input noise as well as the angle of incidence. This paper includes the results of analyzing synthetic and real Doppler ultrasound data that demonstrates the usefulness of the new measure in HRV analysis.

  19. Compressed Sensing Doppler Ultrasound Reconstruction Using Block Sparse Bayesian Learning.

    PubMed

    Lorintiu, Oana; Liebgott, Herve; Friboulet, Denis

    2016-04-01

    In this paper we propose a framework for using duplex Doppler ultrasound systems. These type of systems need to interleave the acquisition and display of a B-mode image and of the pulsed Doppler spectrogram. In a recent study (Richy , 2013), we have shown that compressed sensing-based reconstruction of Doppler signal allowed reducing the number of Doppler emissions and yielded better results than traditional interpolation and at least equivalent or even better depending on the configuration than the study estimating the signal from sparse data sets given in Jensen, 2006. We propose here to improve over this study by using a novel framework for randomly interleaving Doppler and US emissions. The proposed method reconstructs the Doppler signal segment by segment using a block sparse Bayesian learning (BSBL) algorithm based CS reconstruction. The interest of using such framework in the context of duplex Doppler is linked to the unique ability of BSBL to exploit block-correlated signals and to recover non-sparse signals. The performance of the technique is evaluated from simulated data as well as experimental in vivo data and compared to the recent results in Richy , 2013.

  20. Fetal and umbilical Doppler ultrasound in normal pregnancy.

    PubMed

    Alfirevic, Zarko; Stampalija, Tamara; Medley, Nancy

    2015-04-15

    One of the main aims of routine antenatal care is to identify the 'at risk' fetus in order to apply clinical interventions which could result in reduced perinatal morbidity and mortality. Doppler ultrasound study of umbilical artery waveforms helps to identify the compromised fetus in 'high-risk' pregnancies and, therefore, deserves assessment as a screening test in 'low-risk' pregnancies. To assess the effects on obstetric practice and pregnancy outcome of routine fetal and umbilical Doppler ultrasound in unselected and low-risk pregnancies. We searched the Cochrane Pregnancy and Childbirth Group Trials Register (28 February 2015) and reference lists of retrieved studies. Randomised and quasi-randomised controlled trials of Doppler ultrasound for the investigation of umbilical and fetal vessels waveforms in unselected pregnancies compared with no Doppler ultrasound. Studies where uterine vessels have been assessed together with fetal and umbilical vessels have been included. Two review authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. In addition to standard meta-analysis, the two primary outcomes and five of the secondary outcomes were assessed using GRADE software and methodology. We included five trials that recruited 14,624 women, with data analysed for 14,185 women. All trials had adequate allocation concealment, but none had adequate blinding of participants, staff or outcome assessors. Overall and apart from lack of blinding, the risk of bias for the included trials was considered to be low.Overall, routine fetal and umbilical Doppler ultrasound examination in low-risk or unselected populations did not result in increased antenatal, obstetric and neonatal interventions. There were no group differences noted for the review's primary outcomes of perinatal death and neonatal morbidity. Results for perinatal death were as follows: (average risk ratio (RR) 0.80, 95% confidence interval (CI) 0.35 to 1

  1. Power Doppler ultrasound appearances of neonatal ischaemic brain injury.

    PubMed

    Steventon, D M; John, P R

    1997-02-01

    Following neonatal ischaemic brain injury, irregular vessels increase in size owing to luxury perfusion. These may be demonstrated by conventional colour flow Doppler (CFD) imaging at the periphery of the infarcted area. We present a case in which power Doppler imaging (PDI) was performed in addition to CFD in a neonate with unexplained seizures and which proved more sensitive than CFD in demonstrating luxury perfusion. Ultrasound appearances were compared with those seen on cranial CT. PDI can be a useful adjunct to conventional CFD examination of the neonatal brain in cerebral infarction.

  2. Live ultrasound volume reconstruction using scout scanning

    NASA Astrophysics Data System (ADS)

    Meyer, Amelie; Lasso, Andras; Ungi, Tamas; Fichtinger, Gabor

    2015-03-01

    Ultrasound-guided interventions often necessitate scanning of deep-seated anatomical structures that may be hard to visualize. Visualization can be improved using reconstructed 3D ultrasound volumes. High-resolution 3D reconstruction of a large area during clinical interventions is challenging if the region of interest is unknown. We propose a two-stage scanning method allowing the user to perform quick low-resolution scouting followed by high-resolution live volume reconstruction. Scout scanning is accomplished by stacking 2D tracked ultrasound images into a low-resolution volume. Then, within a region of interest defined in the scout scan, live volume reconstruction can be performed by continuous scanning until sufficient image density is achieved. We implemented the workflow as a module of the open-source 3D Slicer application, within the SlicerIGT extension and building on the PLUS toolkit. Scout scanning is performed in a few seconds using 3 mm spacing to allow region of interest definition. Live reconstruction parameters are set to provide good image quality (0.5 mm spacing, hole filling enabled) and feedback is given during live scanning by regularly updated display of the reconstructed volume. Use of scout scanning may allow the physician to identify anatomical structures. Subsequent live volume reconstruction in a region of interest may assist in procedures such as targeting needle interventions or estimating brain shift during surgery.

  3. Effects of transducer, velocity, Doppler angle, and instrument settings on the accuracy of color Doppler ultrasound.

    PubMed

    Stewart, S F

    2001-04-01

    The accuracy of a commercial color Doppler ultrasound (US) system was assessed in vitro using a rotating torus phantom. The phantom consisted of a thin rubber tube filled with a blood-mimicking fluid, joined at the ends to form a torus. The torus was mounted on a disk suspended in water, and rotated at constant speeds by a motor. The torus fluid was shown in a previous study to rotate as a solid body, so that the actual fluid velocity was dependent only on the motor speed and sample volume radius. The fluid velocity could, thus, be easily compared to the color Doppler-derived velocity. The effects of instrument settings, velocity and the Doppler angle was assessed in four transducers: a 2.0-MHz phased-array transducer designed for cardiac use, a 4.0-MHz curved-array transducer designed for general thoracic use, and two linear transducers designed for vascular use (one 4.0 MHz and one 6.0 MHz). The color Doppler accuracy was found to be significantly dependent on the transducer used, the pulse-repetition frequency and wall-filter frequency, the actual fluid velocity and the Doppler angle (p < 0.001 by analysis of variance). In particular, the phased array and curved array were observed to be significantly more accurate than the two linear arrays. The torus phantom was found to provide a sensitive measure of color Doppler accuracy. Clinicians need to be aware of these effects when performing color Doppler US exams.

  4. [The value of Doppler ultrasound studies in threatened premature labor].

    PubMed

    Jörn, H; Funk, A; Fendel, H

    1993-01-01

    95 patients were investigated using Doppler ultrasound to evaluate its usefulness during the clinical management of patients with preterm labor, preterm rupture of membranes and incompetent cervix. Cases with additional pregnancy complications as preeclampsia or intrauterine growth retardation or infection of the amnion or the birth canal were excluded from our study. We examined the umbilical artery and the uterine arteries. Predicting preterm birth we found a sensitivity of 31.4% and a specificity of 70% for the former and a sensitivity of 34.3% and a specificity of 83.3% for the latter. As a result of our investigation we have to conclude that Doppler ultrasound is not able to predict sufficiently reliable preterm birth to use it in clinical management. Normal uterine blood flow in cases with preterm labor seems to indicate birth at term in a high degree.

  5. Adaptive clutter rejection for ultrasound color Doppler imaging

    NASA Astrophysics Data System (ADS)

    Yoo, Yang Mo; Managuli, Ravi; Kim, Yongmin

    2005-04-01

    We have developed a new adaptive clutter rejection technique where an optimum clutter filter is dynamically selected according to the varying clutter characteristics in ultrasound color Doppler imaging. The selection criteria have been established based on the underlying clutter characteristics (i.e., the maximum instantaneous clutter velocity and the clutter power) and the properties of various candidate clutter filters (e.g., projection-initialized infinite impulse response and polynomial regression). We obtained an average improvement of 3.97 dB and 3.27 dB in flow signal-to-clutter-ratio (SCR) compared to the conventional and down-mixing methods, respectively. These preliminary results indicate that the proposed adaptive clutter rejection method could improve the sensitivity and accuracy in flow velocity estimation for ultrasound color Doppler imaging. For a 192 x 256 color Doppler image with an ensemble size of 10, the proposed method takes only 57.2 ms, which is less than the acquisition time. Thus, the proposed method could be implemented in modern ultrasound systems, while providing improved clutter rejection and more accurate velocity estimation in real time.

  6. Sevoflurane Used for Color Doppler Ultrasound Examination in Children.

    PubMed

    Fan, Conghai; Zhang, Fengchao; Huang, Xiaomei; Wen, Cheng; Shan, Chengjing

    2015-05-01

    The objective of this study is to investigate the feasibility of sevoflurane inhalation in pediatric color doppler ultrasound examination. In this study, 30 cases of children under 1 year were selected. They were all I or II levels according to American Society of Anesthesiology. Children with severe cyanotic congenital heart disease or severe pneumonia were excluded. All the children received anesthesia with sevoflurane. The University of Michigan Sedation Scale was assessed and bispectral index (BIS) was recorded before induction (T0), after induction (T1), when maintaining (T2), and when waking-up (T3). Blood pressure and heart rate were monitored during the color doppler ultrasound examination, the time to receive sedation examination and anesthesia recovery time were also recorded. (1) Score for UMSS was zero at T0 and 3 at T1; (2) BIS value was 93.18 ± 2.94 at T0 and decreased to 87.6 ± 3.9 at T1; (3) Blood pressure or heart rate did not decline obviously; (4) The time to receive sedation examination was 46.4 ± 13.1 s and anesthesia recovery time was 7.8 ± 5.3 min. In conclusion, sevoflurane can be used in pediatric color doppler ultrasound examination safely and effectively.

  7. Phase relation recovery for scanning laser Doppler vibrometry

    NASA Astrophysics Data System (ADS)

    Alveringh, D.; Sanders, R. G. P.; Wiegerink, R. J.; Lötters, J. C.

    2017-02-01

    Laser Doppler vibrometers are able to measure the velocity of a single point compared to a reference point by analyzing the Doppler shift of the laser beams. In many commercially available laser Doppler vibrometers, the laser point can be scanned to obtain an out-of-plane velocity profile of a surface. It is essential that the phase information of the velocities between points is measured as well to be able to fully reproduce the velocity profile of the surface. If this cannot be done by triggering on the actuation signal, the proposed two stage method can be used. This method measures the surface in two stages: one scan with the reference beam at a fixed point and one scan with the reference beam on a moving point. The algorithm in this article calculates the phase and reconstructs the velocity of each point. This is experimentally verified on three different micro structures. The postprocessing algorithm is not intensive in computing power.

  8. Scanning phononic lattices with ultrasound

    SciTech Connect

    Vines, R.E.; Wolfe, J.P.; Every, A.V.

    1999-11-01

    A method for probing the elastic properties of newly developed periodic structures using acoustic waves is introduced. Highly anisotropic transmission of surface acoustic waves is observed by continuously scanning the wave vector angle. Preliminary models of wave propagation through multilayers and two-dimensional lattices explain some of the experimental features, while other features can be attributed to the resonant excitation of interface waves. {copyright} {ital 1999} {ital The American Physical Society}

  9. Three-dimensional ultrasound scanning.

    PubMed

    Fenster, Aaron; Parraga, Grace; Bax, Jeff

    2011-08-06

    The past two decades have witnessed developments of new imaging techniques that provide three-dimensional images about the interior of the human body in a manner never before available. Ultrasound (US) imaging is an important cost-effective technique used routinely in the management of a number of diseases. However, two-dimensional viewing of three-dimensional anatomy, using conventional two-dimensional US, limits our ability to quantify and visualize the anatomy and guide therapy, because multiple two-dimensional images must be integrated mentally. This practice is inefficient, and may lead to variability and incorrect diagnoses. Investigators and companies have addressed these limitations by developing three-dimensional US techniques. Thus, in this paper, we review the various techniques that are in current use in three-dimensional US imaging systems, with a particular emphasis placed on the geometric accuracy of the generation of three-dimensional images. The principles involved in three-dimensional US imaging are then illustrated with a diagnostic and an interventional application: (i) three-dimensional carotid US imaging for quantification and monitoring of carotid atherosclerosis and (ii) three-dimensional US-guided prostate biopsy.

  10. Three-dimensional ultrasound scanning

    PubMed Central

    Fenster, Aaron; Parraga, Grace; Bax, Jeff

    2011-01-01

    The past two decades have witnessed developments of new imaging techniques that provide three-dimensional images about the interior of the human body in a manner never before available. Ultrasound (US) imaging is an important cost-effective technique used routinely in the management of a number of diseases. However, two-dimensional viewing of three-dimensional anatomy, using conventional two-dimensional US, limits our ability to quantify and visualize the anatomy and guide therapy, because multiple two-dimensional images must be integrated mentally. This practice is inefficient, and may lead to variability and incorrect diagnoses. Investigators and companies have addressed these limitations by developing three-dimensional US techniques. Thus, in this paper, we review the various techniques that are in current use in three-dimensional US imaging systems, with a particular emphasis placed on the geometric accuracy of the generation of three-dimensional images. The principles involved in three-dimensional US imaging are then illustrated with a diagnostic and an interventional application: (i) three-dimensional carotid US imaging for quantification and monitoring of carotid atherosclerosis and (ii) three-dimensional US-guided prostate biopsy. PMID:22866228

  11. Doppler ultrasound tracking instrument for monitoring blood flow velocity.

    PubMed

    von Krüger, Marco Antônio; Evans, David H

    2002-01-01

    Doppler ultrasound (US) is potentially a valuable method for monitoring changes of blood flow velocity over a period of many minutes or even hours, but is seldom used in this way. One difficulty that may have contributed to this is the problem of maintaining a fixed geometry between the US beam and the blood vessel. A method of improving the success of monitoring might be to actively steer the US beam so as to maintain an adequate signal even when small displacements of the transducer occur. We have designed and built a prototype system for this purpose. The system comprises a continuous-wave phased-array transducer controlled by a purpose-built Doppler unit. The system constantly evaluates the quality of the returning Doppler signal in terms of total power and signal-to-noise ratio (SNR) (evaluated by assessing the quality of derived envelope signals), and steers the ultrasonic beam in a manner so as to improve the signal, should this be necessary. The system was tested in vitro, where the automatic tracking of the Doppler signal doubled the effective beam width of the transducer. Further developments that increase sensitivity and steering range should result in US Doppler systems that are better suited to long-term monitoring.

  12. [Ultrasound and color Doppler in nephrology. Physical and technical principles].

    PubMed

    Meola, Mario; Petrucci, Ilaria

    2012-01-01

    Sonography is an imaging technique that generates tomographic images using ultrasound. The sound constitutes mechanical energy transmitted in a medium by pressure waves. Sound waves with frequencies greater than 20 kHz are called ultrasounds. Diagnostic ultrasounds use frequencies from 1 to 20 MHz. Ultrasound equipment is composed of a scanner, an image monitor, and different transducers that transform acoustic energy into electrical signals and electrical energy into acoustic energy (piezoelectric effect). The spatial resolution defines the minimum distance between two reflectors or echogenic regions that can be imaged as separate reflectors. The spatial resolution is mainly determined by the array design (linear, curved and sectorial) and by the operative system of the transducer. Modern ultrasound machines are very sophisticated medical devices that often support many transducers, imaging modes and display devices. The scan converter memory is the device in which images are formed and then presented to the monitor and to the hard copy devices.

  13. Are Prenatal Ultrasound Scans Associated with the Autism Phenotype? Follow-Up of a Randomised Controlled Trial

    ERIC Educational Resources Information Center

    Stoch, Yonit K.; Williams, Cori J.; Granich, Joanna; Hunt, Anna M.; Landau, Lou I.; Newnham, John P.; Whitehouse, Andrew J. O.

    2012-01-01

    An existing randomised controlled trial was used to investigate whether multiple ultrasound scans may be associated with the autism phenotype. From 2,834 single pregnancies, 1,415 were selected at random to receive ultrasound imaging and continuous wave Doppler flow studies at five points throughout pregnancy (Intensive) and 1,419 to receive a…

  14. The influence of ocular pulsatility on scanning laser Doppler flowmetry.

    PubMed

    Sullivan, P; Cioffi, G A; Wang, L; Johnson, C A; Van Buskirk, E M; Sherman, K R; Bacon, D R

    1999-07-01

    To determine the effect of the cardiac cycle on scanning laser Doppler flowmeter measurements of retinal capillary blood flow in rhesus monkeys and humans. Multiple scanning laser Doppler flowmetry images of rhesus monkey and human retinal capillary blood flow over a range of heart rates were obtained. Average flow values were determined for the 64 scan lines that compose the two-dimensional flow map. Cutaneous blood flow was measured simultaneously with a laser Doppler flowmeter. The temporal relationships between retinal capillary blood flow, peripheral arterial pulse, and cutaneous blood flow were determined. In addition, human retinal capillary blood flow in a 10 x 10-pixel area during different phases of the cardiac cycle was compared. Regular oscillations in human and rhesus monkey retinal capillary blood flow are evident as alternating bright and dark horizontal bands in scanning laser Doppler flowmetry images. These fluctuations are temporally correlated with cutaneous blood flow. Linear regression of actual vs predicted heart rate based on peaks in retinal capillary flow yielded r = 0.999 in a rhesus monkey and 0.938 in a human. Retinal capillary blood flow in a 10 x 10-pixel area fluctuated as much as 50% depending on the phase of the cardiac cycle. The alternating bright and dark banding pattern observed in scanning laser Doppler flowmetry scans of retinal capillary blood flow is related to the cardiac pulse. The errors introduced by pulse-related fluctuations in retinal capillary blood flow are significant and must be minimized or corrected for accurate and reproducible measurements of ocular hemodynamics.

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

    ERIC Educational Resources Information Center

    Looker, T.

    1985-01-01

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

  16. A new clutter rejection algorithm for Doppler ultrasound.

    PubMed

    Cloutier, Guy; Chen, Danmin; Durand, Louis-Gilles

    2003-04-01

    Several strategies, known as clutter or wall Doppler filtering, were proposed to remove the strong echoes produced by stationary or slow moving tissue structures from the Doppler blood flow signal. In this study, the matching pursuit (MP) method is proposed to remove clutter components. The MP method decomposes the Doppler signal into wavelet atoms that are selected in a decreasing energy order. Thus, the high-energy clutter components are extracted first. In the present study, the pulsatile Doppler signal s(n) was simulated by a sum of random-phase sinusoids. Two types of high-amplitude clutter signals were then superimposed on s(n): time-varying low-frequency components, covering systole and early diastole, and short transient clutter signals, distributed within the whole cardiac cycle. The Doppler signals were modeled with the MP method and the most dominant atoms were subtracted from the time-domain signal s(n) until the signal-to-clutter (S/C) ratio reached a maximum. For the low-frequency clutter signal, the improvement in S/C ratio was 19.0 +/- 0.6 dB, and 72.0 +/- 4.5 atoms were required to reach this performance. For the transient clutter signal, ten atoms were required and the maximum improvement in S/C ratio was 5.5 +/- 0.5 dB. The performance of the MP method was also tested on real data recorded over the common carotid artery of a normal subject. Removing 15 atoms significantly improved the appearance of the Doppler sonogram contaminated with low-frequency clutter. Many more atoms (over 200) were required to remove transient clutter components. These results suggest the possibility of using this signal processing approach to implement clutter rejection filters on ultrasound commercial instruments.

  17. Breast ultrasound scans – surgeons’ expectations

    PubMed Central

    Bednarski, Piotr; Chrapowicki, Eryk; Jakubowski, Wiesław

    2015-01-01

    Recent years have witnessed a dynamic development of mammary gland imaging techniques, particularly ultrasonography and magnetic resonance imaging. A challenge related to these studies is the increase in the precision of the anatomical assessment of breast, particularly for early detection of subclinical lesions, performance of ultrasound-guided biopsy procedures, and accurate preoperative location of pathological lesions so as to optimize the surgical treatment. Ultrasound imaging is a primary and baseline diagnostic procedure the patient with suspected pathological lesions within breast is referred to by the surgeon. Lesions visualized in ultrasound scans are classified according to the BI-RADS US assessment categories. The successive categories (2 through 6) encompass individual pathological lesions, estimating the risk of malignancy and provide guidelines for further diagnostic and therapeutic management. This article described the important aspects of ultrasonographic imaging of focal lesions within the breasts as significant from the standpoint of surgical treatment of patients falling within BI-RADS US categories 3, 4, 5, and 6. Attention is drawn to the importance of ultrasound scans in the assessment of axillary fossa lymph nodes before the decision regarding the surgical treatment. PMID:26675118

  18. /sup 201/Tl perfusion study of ''ischemic'' ulcers of the leg: prognostic ability compared with Doppler ultrasound

    SciTech Connect

    Siegel, M.E.; Stewart, C.A.; Kwong, P.; Sakimura, I.

    1982-04-01

    Thallium 201 perfusion analysis was compared with Doppler ultrasound as a means of determining the healing potential of an ischemic ulcer of the leg in 27 patients. The degree of hyperemia was determined by comparative point counting of the /sup 201/Tl distribution in and about the ulcer. Using established Doppler criteria and a hyperemia ratio greater than 1.5:1, ultrasound alone correctly predicted healing in 15 out of 23 cases and /sup 201/Tl in 20 out of 23. Ultrasound correctly predicted non-healing in 3 out of 6 cases, compared with 5 out of 6 for /sup 201/Tl. The positive predictive value of the /sup 201/Tl study was 63%, versus 27% for ultrasound, and the negative predictive value was 95% for /sup 201/Tl and 83% for ultrasound. The accuracy of /sup 201/Tl and ultrasound was 86% and 62%, respectively. This limited study suggests that /sup 201/Tl perfusion scanning is a useful noninvasive test of ulcer healing potential and may be more sensitive than Doppler ultrasound.

  19. Doppler ultrasound and renal artery stenosis: An overview.

    PubMed

    Granata, A; Fiorini, F; Andrulli, S; Logias, F; Gallieni, M; Romano, G; Sicurezza, E; Fiore, C E

    2009-12-01

    Renovascular disease is a complex disorder, most commonly caused by fibromuscular dysplasia and atherosclerotic diseases. It can be found in one of three forms: asymptomatic renal artery stenosis (RAS), renovascular hypertension, and ischemic nephropathy. Particularly, the atherosclerotic form is a progressive disease that may lead to gradual and silent loss of renal function. Thus, early diagnosis of RAS is an important clinical objective since interventional therapy may improve or cure hypertension and preserve renal function. Screening for RAS is indicated in suspected renovascular hypertension or ischemic nephropathy, in order to identify patients in whom an endoluminal or surgical revascularization is advisable. Screening tests for RAS have improved considerably over the last decade. While captopril renography was widely used in the past, Doppler ultrasound (US) of the renal arteries (RAs), angio-CT, or magnetic resonance angiography (MRA) have replaced other modalities and they are now considered the screening tests of choice. An arteriogram is rarely needed for diagnostic purposes only. Color-Doppler US (CDUS) is a noninvasive, repeatable, relatively inexpensive diagnostic procedure which can accurately screen for renovascular diseases if performed by an expert. Moreover, the evaluation of the resistive index (RI) at Doppler US may be very useful in RAS affected patients for predicting the response to revascularization. However, when a discrepancy exists between clinical data and the results of Doppler US, additional tests are mandatory.

  20. An ideal blood mimicking fluid for doppler ultrasound phantoms.

    PubMed

    Samavat, H; Evans, J A

    2006-10-01

    In order to investigate the problems of detecting tumours by ultrasound it is very important to have a portable Doppler flow test object to use as a standardising tool. The flow Doppler test objects are intended to mimic the flow in human arteries. To make the test meaningful, the acoustic properties of the main test object components (tissue and blood mimic) should match closely the properties of the corresponding human tissues, while the tube should ideally have little influence. The blood mimic should also represent the haemodynamic properties of blood. An acceptable flow test object has been designed to closely mimic blood flow in arteries. We have evaluated the properties of three blood mimicking fluid: two have been described recently in the literature, the third is a local design. One of these has emerged as being particularly well matched to the necessary characteristics for in-vitro work.

  1. [Color Doppler ultrasound of the scalp and hair].

    PubMed

    Wortsman, X; Roustan, G; Martorell, A

    2015-11-01

    Color Doppler ultrasound is an imaging technique that allows the study of frequent diseases of the scalp and hair. This examination provides anatomical and functional information in real time that can reveal the extent, activity or severity of common diseases in a non-invasive way, and allows monitoring of their treatment. Copyright © 2015 Academia Española de Dermatología y Venereología. Published by Elsevier España, S.L.U. All rights reserved.

  2. Rotational Dove prism scanning dual angle Doppler OCT

    NASA Astrophysics Data System (ADS)

    Blatter, Cedric; Coquoz, Séverine; Grajciar, Branislav; Singh, Amardeep S. G.; Werkmeister, René M.; Schmetterer, Leopold; Leitgeb, Rainer A.

    2013-03-01

    Traditional Doppler OCT is highly sensitive to motion artifacts due to the dependence on the Doppler angle. This limits its reproducibility in clinical practice. To overcome this limitation, we use a bidirectional technique with a novel rotating scanning scheme. The volume is probed simultaneously from two distinct illumination directions with variable controlled orientations, allowing reconstruction of the true flow velocity, independently of the vessel orientation. A Dove prism in the sample arm permits a rotation of the illumination directions that can be synchronized with the standard beam steering device. The principle is implemented with Swept Source OCT at 1060nm with 100,000 A-Scans/s. We apply the system to human retinal absolute blood velocity measurement by performing segment and circumpapillary time series scans around the optic nerve head. We also demonstrate microvasculature imaging by calculation of squared intensity differences between successive tomograms.

  3. Nonmechanical axial scanning laser Doppler velocimeter with directional discrimination.

    PubMed

    Maru, Koichi; Hata, Takahiro

    2012-07-10

    An axial scanning laser Doppler velocimeter (LDV) with directional discrimination not requiring any moving mechanism in its probe is proposed. The proposed LDV utilizes frequency shift induced by acousto-optic modulators (AOMs) for discriminating the direction of velocity. The measurement position is axially scanned by changing the wavelength of the light input to the probe. The experimental result reveals that both the axial scan and the directional discrimination can be realized by using the proposed method without any moving element in the probe.

  4. Laser-scanning Doppler photoacoustic microscopy based on temporal correlation

    NASA Astrophysics Data System (ADS)

    Song, Wei; Liu, Wenzhong; Zhang, Hao F.

    2013-05-01

    We present a methodology to measure absolute flow velocity using laser-scanning photoacoustic microscopy. To obtain the Doppler angle, the angle between ultrasonic detection axis and flow direction, we extracted the distances between the transducer and three adjacent scanning points along the flow and repeatedly applied the law of cosines. To measure flow velocity along the ultrasonic detection axis, we calculated the time shift between two consecutive photoacoustic waves at the same scanning point, then converted the time shift to velocity according to the sound velocity and time interval between two laser illuminations. We verified our method by imaging flow phantoms.

  5. Assessment of aortic insufficiency by transcutaneous Doppler ultrasound.

    PubMed

    Boughner, D R

    1975-11-01

    Using a 2.2 MHZ directional Doppler ultrasound unit, the instantaneous peak aortic velocity pattern was recorded transcutaneously in 15 normal persons and 15 patients with aortic insufficiency. The transducer was positioned in the suprasternal notch and aimed posteriorly to cross the descending aortic arch at an angle approximately parallel to blood flow. The electrocardiogram, phonocardiogram, and carotid pulse tracings were recorded simultaneously. In patients with aortic insufficiency there was significant diastolic flow that was not present in normal persons. The planimetered area under the systolic and diastolic velocity tracings represents the distance forward and backward that the stroke volume moves. The ratio was used to approximate the percent regurgitation, which ranged from 9% to 68%. From left ventricular angiograms in the patients with aortic regurgitation single plane ventricular volume measurements were used to calculate ventricular output and when compared with the Fick cardiac output gave an estimate of true percent regurgitation. A strong correlation was obtained with the Doppler estimate (r=0.91), confirming that this simple ultrasound technique can accurately assess the degree of aortic insufficiency.

  6. [Noise and speckle reduction in ultrasound Doppler blood flow spectrograms by using MP-PCNN].

    PubMed

    Li, Haiyan; Ma, Yue; Zhang, Yufeng; Shu, Xinling

    2011-10-01

    To reduce background noise and Dopplar speckle in the spectrogram of ultrasound Doppler blood flow signals, a novel method, called Matching Pursuit with threshold decaying pulse coupled neural network (MP-PCNN), has been proposed. The proposed method used an iterative algorithm, which decomposed the ultrasound Doppler signals into linear expansion of atoms in a time-frequency dictionary by using the Matching Pursuit (MP) for de-noising the ultrasound Doppler signal. Subsequently, a simplified unidirectional pulse coupled neural network was applied to calculate the firing matrix of the denoised spectrogram. The Doppler speckles were located and removed through analyzing and processing the PCNN firing matrix. Experiments were conducted on simulation signals which SNRs were 0dB, 5dB and 10dB. The result showed that the MP-PCNN performed effectively in reducing noise, eliminating Doppler speckles, and achieved better performance than exiting noise and speckle suppression algorithm for Doppler ultrasound blood flow spectrogram.

  7. An audit of a hospital-based Doppler ultrasound quality control protocol using a commercial string Doppler phantom.

    PubMed

    Cournane, S; Fagan, A J; Browne, J E

    2014-05-01

    Results from a four-year audit of a Doppler quality assurance (QA) program using a commercially available Doppler string phantom are presented. The suitability of the phantom was firstly determined and modifications were made to improve the reliability and quality of the measurements. QA of Doppler ultrasound equipment is very important as data obtained from these systems is used in patient management. It was found that if the braided-silk filament of the Doppler phantom was exchanged with an O-ring rubber filament and the velocity range below 50 cm/s was avoided for Doppler quality control (QC) measurements, then the maximum velocity accuracy (MVA) error and intrinsic spectral broadening (ISB) results obtained using this device had a repeatability of 18 ± 3.3% and 19 ± 3.5%, respectively. A consistent overestimation of the MVA of between 12% and 56% was found for each of the tested ultrasound systems. Of more concern was the variation of the overestimation within each respective transducer category: MVA errors of the linear, curvilinear and phased array probes were in the range 12.3-20.8%, 32.3-53.8% and 27-40.7%, respectively. There is a dearth of QA data for Doppler ultrasound; it would be beneficial if a multicentre longitudinal study was carried out using the same Doppler ultrasound test object to evaluate sensitivity to deterioration in performance measurements.

  8. Real-time and interactive virtual Doppler ultrasound

    NASA Astrophysics Data System (ADS)

    Hirji, Samira; Downey, Donal B.; Holdsworth, David W.; Steinman, David A.

    2005-04-01

    This paper describes our "virtual" Doppler ultrasound (DUS) system, in which colour DUS (CDUS) images and DUS spectrograms are generated on-the-fly and displayed in real-time in response to position and orientation cues provided by a magnetically tracked handheld probe. As the presence of complex flow often confounds the interpretation of Doppler ultrasound data, this system will serve to be a fundamental tool for training sonographers and gaining insight into the relationship between ambiguous DUS images and complex blood flow dynamics. Recently, we demonstrated that DUS spectra could be realistically simulated in real-time, by coupling a semi-empirical model of the DUS physics to a 3-D computational fluid dynamics (CFD) model of a clinically relevant flow field. Our system is an evolution of this approach where a motion-tracking device is used to continuously update the origin and orientation of a slice passing through a CFD model of a stenosed carotid bifurcation. After calibrating our CFD model onto a physical representation of a human neck, virtual CDUS images from an instantaneous slice are then displayed at a rate of approximately 15 Hz by simulating, on-the-fly, an array of DUS spectra and colour coding the resulting spectral mean velocity using a traditional Doppler colour scale. Mimicking a clinical examination, the operator can freeze the CDUS image on-screen, and a spectrogram corresponding to the selected sample volume location is rendered at a higher frame rate of at least 30 Hz. All this is achieved using an inexpensive desktop workstation and commodity graphics card.

  9. Comparison of blood flow velocity through the internal carotid artery based on Doppler ultrasound and numerical simulation.

    PubMed

    Hassani-Ardekani, Hajar; Ghalichi, Farzan; Niroomand-Oscuii, Hanieh; Farhoudi, Mehdi; Tarzmani, Mohammad Kazem

    2012-12-01

    Doppler ultrasound is a usual non-invasive method to estimate the stenosis percentage in large arteries such as carotid by measuring maximum velocity of blood flow. Based on clinical investigations, because of vessel wall motions, Doppler positioning and angle correction, some errors can arise in Doppler results which lead to incorrect diagnosis. The aim of this study was to compare the results of Doppler test and the numerical simulation of blood flow in the same case. For this evaluation, two patients including an 87-year-old man and a 72-year-old woman suffering from stenosis in the internal carotid artery were selected. First, clinical information of each patient such as CT-Angio scan images and Doppler ultrasound results on different locations of the stenosed artery were obtained. Then, the geometries were reconstructed and numerical simulations were carried out using ANSYS software. Results showed that the velocity profile of Doppler test and numerical simulation were in good agreement at the regions of pre-and post-stenosis. However, the value of maximum velocity at the stenotic region had significant differences.

  10. TU-A-9A-02: Analysis of Variations in Clinical Doppler Ultrasound Peak Velocity Measurements

    SciTech Connect

    Zhang, Y; Stekel, S; Tradup, D; Hangiandreou, N

    2014-06-15

    Purpose: Doppler ultrasound (US) peak velocity (Vmax) measurements show considerable variations due to intrinsic spectral broadening with different scanning techniques, machines and manufacturers. We developed a semi-automated Vmax estimation method and used this method to investigate the performance of a US system for clinical Doppler Vmax measurement. Methods: Semi-automated Vmax is defined as the velocity at which the computed mean spectral profile falls to within 1 background standard deviation of the background mean. GE LOGIQ E9 system with 9L and ML6-15 probes were studied with steady flow (5.3 – 12.5 ml/s) in a Gammex OPTIMIZER 1425A phantom. All Doppler spectra were acquired by 1 operator at the distal end of 5 mm angular tube using a modified clinical carotid artery protocol. Repeatability and variation of Vmax to scanning parameters and probes were analyzed and reported as percentage, i.e. (max-min)/mean. Results: Vmax estimation had good repeatability (3.1% over 6 days for 9L, and 3.6% for ML6-15). For 9L probe, varying gain, compression, scale, SV depth and length, and frequency had minimal impact on Vmax (all variations less than 4.0%). Beam steering had slightly higher influence (largest variations across flow rates were 4.9% for 9L and 6.9% for ML6-15). For both probes, Doppler angle had the greatest effect on Vmax. Percentage increase of Vmax was largely independent of actual flow rates. For Doppler angle varied from 30 to 60°, Vmax increased 24% for 9L, and 20% for ML6-15. Vmax measured by ML6-15 were lower than that by 9L at each Doppler angle with differences less than 5%. Conclusion: The proposed Vmax estimation method is shown to be a useful tool to evaluate clinical Doppler US system performance. For the tested system and probes, Doppler angle had largest impact in measured Vmax.

  11. Color Doppler ultrasound of the hand: observations on clinical utility in rheumatoid arthritis.

    PubMed

    Saadeh, Constantine; Gaylor, Patrick; Lee, Doohi; Malacara, Jan; Gaylor, Michael

    2004-02-01

    The use of ultrasound with color Doppler in the evaluation of rheumatoid arthritis was followed in 25 patients with joint complaints. Small joint ultrasound of the metacarpophalangeal joints (MCPs) as well as the wrists was performed with supplementation by color Doppler. In addition, 6 patients were followed for at least 3 months after start of treatment of rheumatoid arthritis using the same technique. In patients with what appeared to be definite rheumatoid arthritis, ultrasound supported this diagnosis as evidenced by the finding of cortical defects, extensor tendon sheath thickening, and synovial proliferation. Increased activity by color Doppler ultrasonography was the most common finding. Significant decrease in color Doppler activity was noted in the 6 patients who were followed up after 3 months of therapy with disease-modifying agents. Therefore, the use of ultrasound with color Doppler could aid in the diagnosis and follow up of patients with rheumatoid arthritis.

  12. Role of Ultrasound with Color Doppler in Acute Scrotum Management

    PubMed Central

    Agrawal, Alka M.; Tripathi, Prem Siddharth; Shankhwar, Amit; Naveen, C.

    2014-01-01

    Background and Objective: An acute scrotum is defined as acute pain with or without scrotal swelling, may be accompanied by local signs or general symptoms. Acute scrotal pain is a medical emergency. Depending on cause, the management is entirely different. Torsion of testis and strangulated hernia are surgical emergency; whereas, epididymo-orchitis is treated by medicines. Testicular trauma and obstructed hernia can be differentiated by taking history from patient. Physical examination adds only a little information. Color Doppler ultrasound (US) is the modality of choice to differentiate testicular torsion from inflammatory conditions and can thus help in avoiding unnecessary surgical explorations. Subjects and Methods: A study on 50 patients was conducted who were referred with history of acute scrotal pain to our department between January 2013 and January 2014. Trauma and scrotal mass were excluded from the study. The clinical presentation, outcome, and US results were analyzed. Results: Color Doppler sonography yielded a positive and negative predictive value (PPV and NPV) of 100% each for torsion, whereas, 93.9 and 70.6% for epididymo-orchitis, respectively; a sensitivity and specificity of 100% for torsion, whereas, for epididymo-orchitis it was found to be 86.1 and 85.7%, respectively. In cases of incomplete or early torsion, some residual perfusion may be detected leading to false-negative results. Conclusion: We therefore conclude that color Doppler sonography can reliably rule out testicular torsion and can thus help in avoiding unnecessary surgical explorations. Hence, it can significantly improve outcome and decrease morbidity of patient. It is an accurate, rapid, nonexpensive, nonionizing, important adjunct to clinical assessment of scrotum. PMID:25657954

  13. [Doppler ultrasound diagnosis in post-term pregnancy].

    PubMed

    Jörn, H; Funk, A; Fendel, H

    1993-09-01

    The capability of Doppler flow velocimetry to predict intrauterine growth retardation is well known. The increased morbidity and mortality rate of postterm newborns is also well known. The aim of our study was to examine if Doppler flow velocimetry is able to indicate foetal jeopardy in the postterm period. Flow velocimetry of the foetal descending aorta, the umbilical artery, the uterine arteries and in 59 cases also the foetal middle cerebral artery was obtained from 167 pregnancies after 40 completed weeks of gestation. We found significant changes of normal values in prolonged pregnancy compared to third trimester normal values, examining the mean velocity of the foetal descending aorta and the S/D-ratio of the umbilical artery. No clinically significant changes were found examining the S/D-ratio of the uterine arteries and the pulsatility index of the foetal middle cerebral artery. Daily examinations of the foetal descending aorta were carried out in 23 and of the umbilical artery in 19 cases during the last four days before delivery, and in 11 cases of the foetal middle cerebral artery during the last three days before delivery. We did not find significant changes in the medians of the mean velocity of the foetal aorta, of the S/D-ratio of the umbilical artery and of the pulsatility index of the foetal middle cerebral artery. Measurement of sensitivity and positive predictive value of the four arteries examined showed, that Doppler ultrasound could not predict small for date infants or Caesarean section because of foetal distress.(ABSTRACT TRUNCATED AT 250 WORDS)

  14. Doppler ultrasound exam of an arm or leg

    MedlinePlus

    ... the risk of problems with the heart and circulatory system. Most smoking-related deaths are caused by cardiovascular problems, not lung cancer. Alternative Names Peripheral vascular disease - Doppler; PVD - Doppler; PAD - Doppler; Blockage of leg ...

  15. Doppler ultrasonography of the central retinal artery by duplex scanning.

    PubMed

    Steigerwalt, R D; Cesarone, M R; Laurora, G; Belcaro, G V; De Sanctis, M T; Incandela, L; Christopoulos, V

    1996-01-01

    To present duplex scanning of the central retinal artery, which the authors have termed duplex scanner imaging, as an alternative to color Doppler imaging in the evaluation of retinal blood flow velocity, and to show the difference in measurements obtained with the two different techniques. The high-resolution ATL-Ultramark 4 duplex scanner (Advanced Technology Laboratories, Bothell, WA) with the variable focus access probe was used to measure blood flow velocity of the central retinal artery in the eyes of 48 healthy volunteers. Using this technique the peak systolic flow velocity (+/- standard deviation [SD]) of the central retinal artery was 36.6 +/- 10.8 cm/sec, and the end diastolic flow velocity was 12.6 +/- 3.7 cm/sec. The flow velocity measurements of the central retinal artery obtained with this technique were much higher than those obtained by other authors using color Doppler imaging (9.6 cm/sec for the peak systolic flow velocity, and 4.7 cm/sec for the end diastolic flow velocity). The authors propose duplex scanner imaging as an alternative to color Doppler imaging for evaluating retinal blood flow velocity. The duplex scanner also can be used to measure the flow velocity of orbital vessels.

  16. A review of Doppler ultrasound quality assurance protocols and test devices.

    PubMed

    Browne, Jacinta E

    2014-11-01

    In this paper, an overview of Doppler ultrasound quality assurance (QA) testing will be presented in three sections. The first section will review the different Doppler ultrasound parameters recommended by professional bodies for use in QA protocols. The second section will include an evaluation and critique of the main test devices used to assess Doppler performance, while the final section of this paper will discuss which of the wide range of test devices have been found to be most suitable for inclusion in Doppler QA programmes. Pulsed Wave Spectral Doppler, Colour Doppler Imaging QA test protocols have been recommended over the years by various professional bodies, including the UK's Institute of Physics and Engineering in Medicine (IPEM), the American Institute for Ultrasound in Medicine (AIUM), and the International Electrotechnical Commission (IEC). However, despite the existence of such recommended test protocols, very few commercial or research test devices exist which can measure the full range of both PW Doppler ultrasound and colour Doppler imaging performance parameters, particularly quality control measurements such as: (i) Doppler sensitivity (ii) colour Doppler spatial resolution (iii) colour Doppler temporal resolution (iv) colour Doppler velocity resolution (v) clutter filter performance and (vi) tissue movement artefact suppression. In this review, the merits of the various commercial and research test devices will be considered and a summary of results obtained from published studies which have made use of some of these Doppler test devices, such as the flow, string, rotating and belt phantom, will be presented. Copyright © 2014 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  17. B-mode Ultrasound Versus Color Doppler Twinkling Artifact in Detecting Kidney Stones

    PubMed Central

    Harper, Jonathan D.; Hsi, Ryan S.; Shah, Anup R.; Dighe, Manjiri K.; Carter, Stephen J.; Moshiri, Mariam; Paun, Marla; Lu, Wei; Bailey, Michael R.

    2013-01-01

    Abstract Purpose To compare color Doppler twinkling artifact and B-mode ultrasonography in detecting kidney stones. Patients and Methods Nine patients with recent CT scans prospectively underwent B-mode and twinkling artifact color Doppler ultrasonography on a commercial ultrasound machine. Video segments of the upper pole, interpolar area, and lower pole were created, randomized, and independently reviewed by three radiologists. Receiver operator characteristics were determined. Results There were 32 stones in 18 kidneys with a mean stone size of 8.9±7.5 mm. B-mode ultrasonography had 71% sensitivity, 48% specificity, 52% positive predictive value, and 68% negative predictive value, while twinkling artifact Doppler ultrasonography had 56% sensitivity, 74% specificity, 62% positive predictive value, and 68% negative predictive value. Conclusions When used alone, B-mode is more sensitive, but twinkling artifact is more specific in detecting kidney stones. This information may help users employ twinkling and B-mode to identify stones and developers to improve signal processing to harness the fundamental acoustic differences to ultimately improve stone detection. PMID:23067207

  18. Usage of eigenvector methods to improve reliable classifier for Doppler ultrasound signals.

    PubMed

    Ubeyli, Elif Derya

    2008-05-01

    A new approach based on the implementation of the automated diagnostic systems for Doppler ultrasound signals classification with the features extracted by eigenvector methods is presented. In practical applications of pattern recognition, there are often diverse features extracted from raw data which needs recognizing. Because of the importance of making the right decision, the present work is carried out for searching better classification procedures for the Doppler ultrasound signals. Decision making was performed in two stages: feature extraction by the eigenvector methods and classification using the classifiers trained on the extracted features. The aim of the study is classification of the Doppler ultrasound signals by the combination of eigenvector methods and the classifiers. The present research demonstrated that the power levels of the power spectral density (PSD) estimates obtained by the eigenvector methods are the features which well represent the Doppler ultrasound signals and the probabilistic neural networks (PNNs), recurrent neural networks (RNNs) trained on these features achieved high classification accuracies.

  19. Measurement of Thermal Effects of Doppler Ultrasound: An In Vitro Study

    PubMed Central

    Helmy, Samir; Bader, Yvonne; Koch, Marianne; Tiringer, Denise; Kollmann, Christian

    2015-01-01

    Objective Ultrasound is considered a safe imaging modality and is routinely applied during early pregnancy. However, reservations are expressed concerning the application of Doppler ultrasound in early pregnancy due to energy emission of the ultrasound probe and its conversion to heat. The objective of this study was to evaluate the thermal effects of emitted Doppler ultrasound of different ultrasound machines and probes by means of temperature increase of in-vitro test-media. Methods We investigated the energy-output of 5 vaginal and abdominal probes of 3 ultrasound machines (GE Healthcare, Siemens, Aloka). Two in-vitro test objects were developed at the Center for Medical Physics and Biomedical Engineering, Medical University Vienna (water bath and hydrogel bath). Temperature increase during Doppler ultrasound emission was measured via thermal sensors, which were placed inside the test objects or on the probes’ surface. Each probe was emitting for 5 minutes into the absorbing test object with 3 different TI/MI settings in Spectral Doppler mode. Results During water bath test, temperature increase varied between 0.1 and 1.0°C, depending on probe, setting and focus, and was found highest for spectral Doppler mode alone. Maximum temperature increase was found during the surface heating test, where values up to 2.4°C could be measured within 5 minutes of emission. Conclusions Activation of Doppler ultrasound in the waterbath model causes a significant increase of temperature within one minute. Thermally induced effects on the embryo cannot be excluded when using Doppler ultrasound in early pregnancy. PMID:26302465

  20. Measurement of Thermal Effects of Doppler Ultrasound: An In Vitro Study.

    PubMed

    Helmy, Samir; Bader, Yvonne; Koch, Marianne; Tiringer, Denise; Kollmann, Christian

    2015-01-01

    Ultrasound is considered a safe imaging modality and is routinely applied during early pregnancy. However, reservations are expressed concerning the application of Doppler ultrasound in early pregnancy due to energy emission of the ultrasound probe and its conversion to heat. The objective of this study was to evaluate the thermal effects of emitted Doppler ultrasound of different ultrasound machines and probes by means of temperature increase of in-vitro test-media. We investigated the energy-output of 5 vaginal and abdominal probes of 3 ultrasound machines (GE Healthcare, Siemens, Aloka). Two in-vitro test objects were developed at the Center for Medical Physics and Biomedical Engineering, Medical University Vienna (water bath and hydrogel bath). Temperature increase during Doppler ultrasound emission was measured via thermal sensors, which were placed inside the test objects or on the probes' surface. Each probe was emitting for 5 minutes into the absorbing test object with 3 different TI/MI settings in Spectral Doppler mode. During water bath test, temperature increase varied between 0.1 and 1.0°C, depending on probe, setting and focus, and was found highest for spectral Doppler mode alone. Maximum temperature increase was found during the surface heating test, where values up to 2.4°C could be measured within 5 minutes of emission. Activation of Doppler ultrasound in the waterbath model causes a significant increase of temperature within one minute. Thermally induced effects on the embryo cannot be excluded when using Doppler ultrasound in early pregnancy.

  1. Differential diagnosis of prerenal azotemia from acute tubular necrosis and prediction of recovery by Doppler ultrasound.

    PubMed

    Izumi, M; Sugiura, T; Nakamura, H; Nagatoya, K; Imai, E; Hori, M

    2000-04-01

    Acute renal failure (ARF) is a life-threatening disease that often causes multiple organ dysfunction. The accurate and rapid diagnosis of the cause of ARF is particularly important for selecting the appropriate therapy. Ultrasound Doppler is a noninvasive diagnostic method that has recently been introduced to clinical nephrology. We report the diagnostic value of Doppler ultrasound in differentiating acute tubular necrosis (ATN) from prerenal azotemia by comparing this study with the fractional excretion of sodium (FENa), renal failure index (RFI), and urinary/serum creatinine (Cr) ratio. Doppler ultrasound was able to differentiate prerenal azotemia from ATN, equivalent to FENa, RFI, and the urinary/serum Cr ratio. Doppler ultrasound does not require blood or urine samples and can be performed at the bedside. Of note, Doppler is unaffected by changes in Na or Cr in urine or serum after diuretics or hemodialysis. Furthermore, one can predict recovery from ATN by Doppler findings. Thus, we consider Doppler ultrasound an effective diagnostic tool in ARF.

  2. Our experience in the diagnosis of intraocular tumours by a B-scan computerized system and angiodynography (Doppler). Preliminary results.

    PubMed

    Falco, L; Esente, S; Fanfani, S; Pasarelli, N; Utari, S

    1992-01-01

    The authors compare the ultrasound diagnostic results of intraocular tumours by A/B-scans (Sonomed B 3000, Sonocare, Sonovision STT-100) with images obtained using computerized B-scan (Sonocare, Sonovision STT-100, Acoustic Tissue Typing ATT) and angiodynopgraphy systems (Quantum Philips). The Sonovision uses a computerized ultrasound spectrum analysis to assess the probability that a given lesion is a certain tumour, rather than another. The ATT system provides diagnostic probability for type B and type E melanoma, for haemangioma and metastatic carcinoma. The Quantum ultrasound equipment was developed for studying the heart and the major blood vessels. It is a colour Doppler that simplifies the Doppler technique, allowing it to study small anatomical parts such as tumour-like lesions of the eye. The Doppler technique ascertains the presence and the velocity of blood flow in the tumours. In presenting the preliminary results with the new techniques the authors are aware that the ATT system is not designed for some of the lesions under study (melanomas after conservative radiotherapy).

  3. Use of ultrasound, color Doppler imaging and radiography to monitor periapical healing after endodontic surgery.

    PubMed

    Tikku, Aseem P; Kumar, Sunil; Loomba, Kapil; Chandra, Anil; Verma, Promila; Aggarwal, Renu

    2010-09-01

    This study evaluated the effectiveness of ultrasound, color Doppler imaging and conventional radiography in monitoring the post-surgical healing of periapical lesions of endodontic origin. Fifteen patients who underwent periapical surgery for endodontic pathology were randomly selected. In all patients, periapical lesions were evaluated preoperatively using ultrasound, color Doppler imaging and conventional radiography, to analyze characteristics such as size, shape and dimensions. On radiographic evaluation, dimensions were measured in the superoinferior and mesiodistal direction using image-analysis software. Ultrasound evaluation was used to measure the changes in shape and dimensions on the anteroposterior, superoinferior, and mesiodistal planes. Color Doppler imaging was used to detect the blood-flow velocity. Postoperative healing was monitored in all patients at 1 week and 6 months by using ultrasound and color Doppler imaging, together with conventional radiography. The findings were then analyzed to evaluate the effectiveness of the 3 imaging techniques. At 6 months, ultrasound and color Doppler imaging were significantly better than conventional radiography in detecting changes in the healing of hard tissue at the surgical site (P < 0.004). This study demonstrates that ultrasound and color Doppler imaging have the potential to supplement conventional radiography in monitoring the post-surgical healing of periapical lesions of endodontic origin.

  4. The effect of dead elements on the accuracy of Doppler ultrasound measurements.

    PubMed

    Vachutka, Jaromir; Dolezal, Ladislav; Kollmann, Christian; Klein, Jakob

    2014-01-01

    The objective of this study is to investigate the effect of multiple dead elements in an ultrasound probe on the accuracy of Doppler ultrasound measurements. For this work, we used a specially designed ultrasound imaging system, the Ultrasonix Sonix RP, that provides the user with the ability to disable selected elements in the probe. Using fully functional convex, linear, and phased array probes, we established a performance baseline by measuring the parameters of a laminar parabolic flow profile. These same parameters were then measured using probes with 1 to 10 disabled elements. The acquired velocity spectra from the functional probes and the probes with disabled elements were then analyzed to determine the overall Doppler power, maximum flow velocity, and average flow velocity. Color Flow Doppler images were also evaluated in a similar manner. The analysis of the Doppler spectra indicates that the overall Doppler power as well as the detected maximum and average velocities decrease with the increasing number of disabled elements. With multiple disabled elements, decreases in the detected maximum and average velocities greater than 20% were recorded. Similar results were also observed with Color Flow Doppler measurements. Our results confirmed that the degradation of the ultrasound probe through the loss of viable elements will negatively affect the quality of the Doppler-derived diagnostic information. We conclude that the results of Doppler measurements cannot be considered accurate or reliable if there are four or more contiguous dead elements in any given probe.

  5. Direct Measurement of Basilar Membrane Motion Using Pulsed-Wave Doppler High-Frequency Ultrasound

    NASA Astrophysics Data System (ADS)

    Torbatian, Z.; Garland, P.; Adamson, R. B. A.; Bance, M.; Brown, J. A.

    2011-11-01

    We present a preliminary report on the use of a new technique for measuring the motion of the basilar membrane, high-frequency ultrasound Doppler vibrometry. Using a custom-built, 1 mm diameter probe, we collected ultrasonic reflections from intracochlear structures and applied pulsed-wave Doppler vibrometry to measure the basilar membrane response to pressure applied in the ear canal.

  6. Measurement of neonatal heart rate using handheld Doppler ultrasound.

    PubMed

    Dyson, Amanda; Jeffrey, Michele; Kluckow, Martin

    2017-03-01

    This pilot study aimed to determine whether handheld Doppler ultrasound is feasible and reliable for measuring neonatal heart rate (HR) when compared with ECG. Stable newborns were recruited from the neonatal intensive care unit and postnatal ward between July 2014 and January 2015 at Royal North Shore Hospital, Sydney, Australia. Each newborn had their HR recorded every 15 s over 145 s using four different modalities: ECG, counted audible Doppler (AD) over 10 s, pulse oximetry (PO) and the Doppler display (DD). The correlation and variation between each modality and ECG. 51 newborns with a median gestational age of 38 weeks (27-41) and a mean weight of 2.78 kg (0.82 to 4.76) with a median postnatal age of 3 days (0-87) were studied. There was a mean difference of 0.69 bpm (95% CI -2.9 to +1.5) between AD-HR and ECG-HR with good correlation between modalities (r=0.94, p<0.01). The median time to achieve AD-HR was 3 s (1-45). The mean difference between DD-HR and ECG-HR was 5.37 bpm (95% CI -12.8 to +2.1) with moderate correlation (r=0.37, p=0.04). The mean difference between PO-HR and ECG-HR was 0.49 bpm (95% CI -1.5 to +0.51) with good correlation (r=0.99, p<0.01). The variability between AD-HR and ECG-HR decreased with decreasing weight. AD-HR correlates well with ECG-HR. Further research in the delivery room is recommended before using AD-HR in this area. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  7. Wind Measurements from Arc Scans with Doppler Wind Lidar

    SciTech Connect

    Wang, H.; Barthelmie, R. J.; Clifton, Andy; Pryor, S. C.

    2015-11-25

    When defining optimal scanning geometries for scanning lidars for wind energy applications, we found that it is still an active field of research. Our paper evaluates uncertainties associated with arc scan geometries and presents recommendations regarding optimal configurations in the atmospheric boundary layer. The analysis is based on arc scan data from a Doppler wind lidar with one elevation angle and seven azimuth angles spanning 30° and focuses on an estimation of 10-min mean wind speed and direction. When flow is horizontally uniform, this approach can provide accurate wind measurements required for wind resource assessments in part because of its high resampling rate. Retrieved wind velocities at a single range gate exhibit good correlation to data from a sonic anemometer on a nearby meteorological tower, and vertical profiles of horizontal wind speed, though derived from range gates located on a conical surface, match those measured by mast-mounted cup anemometers. Uncertainties in the retrieved wind velocity are related to high turbulent wind fluctuation and an inhomogeneous horizontal wind field. Moreover, the radial velocity variance is found to be a robust measure of the uncertainty of the retrieved wind speed because of its relationship to turbulence properties. It is further shown that the standard error of wind speed estimates can be minimized by increasing the azimuthal range beyond 30° and using five to seven azimuth angles.

  8. Wind Measurements from Arc Scans with Doppler Wind Lidar

    DOE PAGES

    Wang, H.; Barthelmie, R. J.; Clifton, Andy; ...

    2015-11-25

    When defining optimal scanning geometries for scanning lidars for wind energy applications, we found that it is still an active field of research. Our paper evaluates uncertainties associated with arc scan geometries and presents recommendations regarding optimal configurations in the atmospheric boundary layer. The analysis is based on arc scan data from a Doppler wind lidar with one elevation angle and seven azimuth angles spanning 30° and focuses on an estimation of 10-min mean wind speed and direction. When flow is horizontally uniform, this approach can provide accurate wind measurements required for wind resource assessments in part because of itsmore » high resampling rate. Retrieved wind velocities at a single range gate exhibit good correlation to data from a sonic anemometer on a nearby meteorological tower, and vertical profiles of horizontal wind speed, though derived from range gates located on a conical surface, match those measured by mast-mounted cup anemometers. Uncertainties in the retrieved wind velocity are related to high turbulent wind fluctuation and an inhomogeneous horizontal wind field. Moreover, the radial velocity variance is found to be a robust measure of the uncertainty of the retrieved wind speed because of its relationship to turbulence properties. It is further shown that the standard error of wind speed estimates can be minimized by increasing the azimuthal range beyond 30° and using five to seven azimuth angles.« less

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

    PubMed

    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.

  10. Doppler ultrasound study and venous mapping in chronic venous insufficiency.

    PubMed

    García Carriazo, M; Gómez de las Heras, C; Mármol Vázquez, P; Ramos Solís, M F

    2016-01-01

    Chronic venous insufficiency of the lower limbs is very prevalent. In recent decades, Doppler ultrasound has become the method of choice to study this condition, and it is considered essential when surgery is indicated. This article aims to establish a method for the examination, including venous mapping and preoperative marking. To this end, we review the venous anatomy of the lower limbs and the pathophysiology of chronic venous insufficiency and explain the basic hemodynamic concepts and the terminology required to elaborate a radiological report that will enable appropriate treatment planning and communication with other specialists. We briefly explain the CHIVA (the acronym for the French term "cure conservatrice et hémodynamique de l'insuffisance veineuse en ambulatoire"=conservative hemodynamic treatment for chronic venous insufficiency) strategy, a minimally invasive surgical strategy that aims to restore correct venous hemodynamics without resecting the saphenous vein. Copyright © 2015 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

  11. Breast tumor angiogenesis analysis using 3D power Doppler ultrasound

    NASA Astrophysics Data System (ADS)

    Chang, Ruey-Feng; Huang, Sheng-Fang; Lee, Yu-Hau; Chen, Dar-Ren; Moon, Woo Kyung

    2006-03-01

    Angiogenesis is the process that correlates to tumor growth, invasion, and metastasis. Breast cancer angiogenesis has been the most extensively studied and now serves as a paradigm for understanding the biology of angiogenesis and its effects on tumor outcome and patient prognosis. Most studies on characterization of angiogenesis focus on pixel/voxel counts more than morphological analysis. Nevertheless, in cancer, the blood flow is greatly affected by the morphological changes, such as the number of vessels, branching pattern, length, and diameter. This paper presents a computer-aided diagnostic (CAD) system that can quantify vascular morphology using 3-D power Doppler ultrasound (US) on breast tumors. We propose a scheme to extract the morphological information from angiography and to relate them to tumor diagnosis outcome. At first, a 3-D thinning algorithm helps narrow down the vessels into their skeletons. The measurements of vascular morphology significantly rely on the traversing of the vascular trees produced from skeletons. Our study of 3-D assessment of vascular morphological features regards vessel count, length, bifurcation, and diameter of vessels. Investigations into 221 solid breast tumors including 110 benign and 111 malignant cases, the p values using the Student's t-test for all features are less than 0.05 indicating that the proposed features are deemed statistically significant. Our scheme focuses on the vascular architecture without involving the technique of tumor segmentation. The results show that the proposed method is feasible, and have a good agreement with the diagnosis of the pathologists.

  12. Transcranial Doppler ultrasound in children with stroke and cerebrovascular disorders.

    PubMed

    LaRovere, Kerri L

    2015-12-01

    A major advantage of transcranial Doppler (TCD) ultrasound is its ability to measure cerebral hemodynamics noninvasively at the patient's bedside. This article summarizes the basic physics and variables used during TCD, recent pediatric data published on the use of TCD in stroke and cerebrovascular disorders and how it may impact diagnosis and management, and some issues to be resolved so that TCD can be put into clinical practice. In sickle cell disease in children, TCD is the gold standard stroke prediction tool. Recent data suggest that TCD may provide important information in ischemic stroke because of other childhood arteriopathies such as moyamoya syndrome, transient or focal cerebral arteriopathy, and genetic/syndromic causes. TCD may also detect cerebral emboli and diagnose right-to-left atrial cardiac shunts in children with cryptogenic stroke and transient ischemic attack. There are many potential clinical applications for TCD in pediatric stroke and cerebrovascular disorders. Additional research in children is needed to determine whether TCD can identify markers of increased stroke risk, elucidate underlying stroke mechanisms, influence the choice of additional testing and treatment, and ultimately impact patient outcomes.

  13. Effect of gel-instillation sonography on Doppler ultrasound findings in endometrial polyps.

    PubMed

    Van Den Bosch, T; Van Schoubroeck, D; Luts, J; Bignardi, T; Condous, G; Epstein, E; Leone, F P; Testa, A C; Valentin, L; Van Huffel, S; Bourne, T; Timmerman, D

    2011-09-01

    Saline infusion sonohysterography has been reported to suppress the color signal within the endometrium at color or power Doppler evaluation. The aim of this study was to evaluate if gel-instillation sonography (GIS) affects the power Doppler signal in patients with endometrial polyps. Ultrasound volumes of the uterus, obtained by three-dimensional ultrasound imaging of 25 women with histologically confirmed endometrial polyps, were assessed offline by six gynecologists with a special interest in gynecological ultrasound. Each woman contributed four volumes: one gray-scale volume and one power Doppler volume before GIS, and one gray-scale volume and one power Doppler volume at GIS. Power Doppler features before and after gel infusion were compared. At unenhanced ultrasound a pedicle artery was seen in 27-46% of cases, whereas, after gel infusion the examiners reported a pedicle artery in 30-46% of cases (Exact McNemar's test P-values ranged from 0.50 to 1.00). The level of agreement between unenhanced ultrasound and GIS ranged from 59 to 91% (Cohen's kappa values ranged from 0.17 to 0.79). There was no tendency for a pedicle artery to be identified less often at GIS than before gel instillation. Gel infusion does not affect the power Doppler signal in patients with endometrial polyps. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.

  14. Multidimensional Ultrasound Doppler Signal Analysis for Fetal Activity Monitoring.

    PubMed

    Ribes, Sophie; Girault, Jean-Marc; Perrotin, Franck; Kouamé, Denis

    2015-12-01

    Fetal activity parameters such as movements, heart rate and the related parameters are essential indicators of fetal wellbeing, and no device provides simultaneous access to and sufficient estimation of all of these parameters to evaluate fetal health. This work was aimed at collecting these parameters to automatically separate healthy from compromised fetuses. To achieve this goal, we first developed a multi-sensor-multi-gate Doppler system. Then we recorded multidimensional Doppler signals and estimated the fetal activity parameters via dedicated signal processing techniques. Finally, we combined these parameters into four sets of parameters (or four hyper-parameters) to determine the set of parameters that is able to separate healthy from other fetuses. To validate our system, a data set consisting of two groups of fetal signals (normal and compromised) was established and provided by physicians. From the estimated parameters, an instantaneous Manning-like score, referred to as the ultrasonic score, was calculated and was used together with movements, heart rate and the associated parameters in a classification process employing the support vector machine method. We investigated the influence of the sets of parameters and evaluated the performance of the support vector machine using the computation of sensibility, specificity, percentage of support vectors and total classification error. The sensitivity of the four sets ranged from 79% to 100%. Specificity was 100% for all sets. The total classification error ranged from 0% to 20%. The percentage of support vectors ranged from 33% to 49%. Overall, the best results were obtained with the set of parameters consisting of fetal movement, short-term variability, long-term variability, deceleration and ultrasound score. The sensitivity, specificity, percentage of support vectors and total classification error of this set were respectively 100%, 100%, 35% and 0%. This indicated our ability to separate the data into two

  15. The commodification of obstetric ultrasound scanning in Hanoi, Viet Nam.

    PubMed

    Gammeltoft, Tine; Nguyen, Hanh Thi Thuý

    2007-05-01

    Growing numbers of pregnant women across the world now routinely have ultrasound scans as part of antenatal care, including in low-income countries. This article presents the findings of anthropological research on the use of obstetric ultrasonography in routine antenatal care in Hanoi, Viet Nam. The findings come from observation, a survey and interviews with women seeking ultrasound scans at a main maternity hospital and interviews with doctors providing ultrasound there. We found a dramatic overuse of ultrasound scanning; the 400 women surveyed had had an average of 6.6 scans and 8.3 antenatal visits during pregnancy, while one-fifth had had ten scans or more. Doctors considered obstetric ultrasound an indispensable part of modern antenatal care. For two-thirds of the women, the main reason for frequent scans was reassurance of normal fetal development. However, the women often also said their doctor had recommended the scans. This overuse must be seen in the context of growing commercialisation in the Vietnamese health care system, where ultrasound provides an important source of revenue for both private and public providers. There is an urgent need in Viet Nam for policy and practice guidelines on the appropriate use of ultrasonography in pregnancy and how best to combine it with essential antenatal care, and information dissemination to women.

  16. Transthoracic needle biopsy of thoracic tumours by a colour Doppler ultrasound puncture guiding device.

    PubMed Central

    Wang, H. C.; Yu, C. J.; Chang, D. B.; Yuan, A.; Lee, Y. C.; Yang, P. C.; Kuo, S. H.; Luh, K. T.

    1995-01-01

    BACKGROUND--Ultrasound guided transthoracic needle aspiration biopsy has recently been used to obtain specimens for histological diagnosis of pulmonary and mediastinal tumours. Conventional real time, grey scale puncture guiding devices cannot differentiate vascular structures, and clear visualisation of the needle shaft or tip within a desired target is not always possible. This study describes a new built-in colour Doppler ultrasound puncture guiding device and assesses the relative safety of transthoracic needle aspiration biopsy of thoracic tumours by grey scale or colour Doppler ultrasound guidance. METHODS--Thirty patients with radiographic evidence of pulmonary (22 patients) or mediastinal tumours (eight patients) underwent ultrasonographic evaluation and transthoracic needle aspiration biopsy by using the colour Doppler ultrasound puncture guiding device (Aloka UST 5045P-3.5). These tumours were initially examined by grey scale ultrasound, and colour Doppler imaging was then used to evaluate the number of blood vessels surrounding and within the target tumour and the possibility of visualisation of the needle shaft or needle tip during the aspiration biopsy procedure. RESULTS--The colour Doppler ultrasound guiding device was far superior to the grey scale device for identification of the number of vessels surrounding or within the target tumour (83% v 20%) and for visualisation of the needle shaft or needle tip (80% v 17%). CONCLUSIONS--By using the colour Doppler ultrasound puncture device, vascular structures surrounding or within the target tumour can be verified. Visualisation of the needle shaft or tip is also better. Biopsy routes can be selected to avoid puncturing vessels. This approach should be particularly helpful for guiding biopsies of mediastinal tumours, where puncturing the heart or great vessels is a potential complication. Images PMID:8553297

  17. [Duplex ultrasound and color-coded Doppler ultrasound of visceral blood vessels in abdominal diseases].

    PubMed

    Mostbeck, G; Mallek, R; Gebauer, A; Tscholakoff, D

    1992-01-01

    Duplex Doppler sonography (DS) and color-flow Doppler sonography (FDS) are noninvasive diagnostic methods for the evaluation of a patient with suspected vascular disease of the abdomen. They represent a useful adjunct to realtime sonography in the identification of normal and variant visceral vascular anatomy. Aneurysms and pseudo-aneurysms of visceral arteries are readily differentiated from other cystic lesions. DS and FDS have a high sensitivity in the detection of portal vein thrombosis and stenosis. Both methods allow the observation and measurement of splanchnic hemodynamics in patients with chronic liver disease and portal hypertension. Hence, DS and FDS already play an important role in the pre- and postoperative assessment of patients undergoing liver or pancreas transplantation. The possibility that DS and FDS may enable discrimination between hypovascular and hypervascular tumors is under clinical investigation. FDS facilitates an excellent anatomic display of the abdominal vasculature and allows easy placement of the Doppler sample volume. Consequently, quantitative data acquired with DS are accomplished within short scanning times. However, the diagnostic impact of both modalities depends to a great extent on the experience of the investigator.

  18. [Ultrasound and color Doppler applications in chronic kidney disease].

    PubMed

    Meola, Mario; Petrucci, Ilaria

    2012-01-01

    Chronic kidney disease (CKD) encompasses all clinical features and complications during the progression of various kidney conditions towards end-stage renal disease. These conditions include immune and inflammatory diseases such as primary and HCV-related glomerulonephritis; infectious diseases such as pyelonephritis with or without reflux and tuberculosis; vascular diseases such as chronic ischemic nephropathy; hereditary and congenital diseases such as polycystic disease and congenital cystic dysplasia; metabolic diseases including diabetes and hyperuricemia; and systemic diseases (collagen disease, vasculitis, myeloma). During the progression of CKD, ultrasound imaging can differentiate the nature of the renal damage in only 50-70% of cases. Infact, the end-stage kidney appears shrunken, reduced in volume (Ø <9 cm), unstructured, amorphous, with acquired cystic degeneration (small and multiple cysts involving the cortex and medulla) or nephrocalcinosis, but there are rare exceptions, such as polycystic kidney disease, diabetic nephropathy, and secondary inflammatory nephropathies. The main difficulties in the differential diagnosis are encountered in multifactorial CKD, which is commonly presented to the nephrologist at stage 4-5, when the kidney is shrunken, unstructured and amorphous. As in acute renal injury and despite the lack of sensitivity, ultrasonography is essential for assessing the progression of the renal damage and related complications, and for evaluating all conditions that increase the risk of CKD, such as lithiasis, recurrent urinary tract infections, vesicoureteral reflux, polycystic kidney disease and obstructive nephropathy. The timing and frequency of ultrasound scans in CKD patients should be evaluated case by case. In this review we will consider the morphofunctional features of the kidney in all nephropathies that may lead to progressive CKD.

  19. Prevalence in a volunteer population of pelvic cancer detected with transvaginal ultrasound and color flow Doppler.

    PubMed

    Schulman, H; Conway, C; Zalud, I; Farmakides, G; Haley, J; Cassata, M

    1994-09-01

    Our objective was to find the prevalence of non-symptomatic endometrial and ovarian neoplasms in a volunteer population of women, aged 40 and over. We offered a free volunteer screening program to asymptomatic women for a study using transvaginal ultrasound and color flow Doppler for the detection of pelvic cancer. In the first 2 years, 2117 women were examined, 51.3% post-menopausal. An ovarian cyst was defined as having a maximum diameter of more than 2.4 cm. Color flow was used to identify blood vessels feeding pelvic organs and adnexal enlargements. An abnormal Doppler flow velocity for the ovary was defined as a resistance index of less than 0.41. Ovarian cysts of less than 5 cm with normal Doppler indices were followed up in 6 months to 1 year. An adnexal morphology score was created to quantify the usefulness of this parameter, particularly in postmenopausal women. Indications for surgery were pre-defined as a persistent ovarian cyst of more than 5 cm, a persistent suspicious Doppler and a total endometrial thickness of greater than 0.59 cm in postmenopausal women not taking hormones.A total of 202 women (9.5%) had ovarian cysts. Fourteen women were operated upon because of size criteria, one because of family history and three for persistent abnormal flow. By Doppler study, 15 cysts were predicted to be benign and histology was confirmatory. There were two false positives and one true positive, a stage Ib ovarian cancer. There were no false negatives, although a stage I endometrioid cancer of the ovary was detected 8 months after a negative scan. In those cases in which follow-up data were available, 56% of the cysts regressed in premenopausal women. In postmenopausal women, 28% regressed. Twenty of 1086 postmenopausal women had endometrial biopsies. Three had endometrial cancer, two stage I and one stage IIA. Five had atypical or adenomatous hyperplasia, and seven had benign polyps. So many women have small asymptomatic cysts of the ovary that a major

  20. Using rotation for steerable needle detection in 3D color-Doppler ultrasound images.

    PubMed

    Mignon, Paul; Poignet, Philippe; Troccaz, Jocelyne

    2015-08-01

    This paper demonstrates a new way to detect needles in 3D color-Doppler volumes of biological tissues. It uses rotation to generate vibrations of a needle using an existing robotic brachytherapy system. The results of our detection for color-Doppler and B-Mode ultrasound are compared to a needle location reference given by robot odometry and robot ultrasound calibration. Average errors between detection and reference are 5.8 mm on needle tip for B-Mode images and 2.17 mm for color-Doppler images. These results show that color-Doppler imaging leads to more robust needle detection in noisy environment with poor needle visibility or when needle interacts with other objects.

  1. A new fringeline-tracking approach for color Doppler ultrasound imaging phase unwrapping

    NASA Astrophysics Data System (ADS)

    Saad, Ashraf A.; Shapiro, Linda G.

    2008-03-01

    Color Doppler ultrasound imaging is a powerful non-invasive diagnostic tool for many clinical applications that involve examining the anatomy and hemodynamics of human blood vessels. These clinical applications include cardio-vascular diseases, obstetrics, and abdominal diseases. Since its commercial introduction in the early eighties, color Doppler ultrasound imaging has been used mainly as a qualitative tool with very little attempts to quantify its images. Many imaging artifacts hinder the quantification of the color Doppler images, the most important of which is the aliasing artifact that distorts the blood flow velocities measured by the color Doppler technique. In this work we will address the color Doppler aliasing problem and present a recovery methodology for the true flow velocities from the aliased ones. The problem is formulated as a 2D phase-unwrapping problem, which is a well-defined problem with solid theoretical foundations for other imaging domains, including synthetic aperture radar and magnetic resonance imaging. This paper documents the need for a phase unwrapping algorithm for use in color Doppler ultrasound image analysis. It describes a new phase-unwrapping algorithm that relies on the recently developed cutline detection approaches. The algorithm is novel in its use of heuristic information provided by the ultrasound imaging modality to guide the phase unwrapping process. Experiments have been performed on both in-vitro flow-phantom data and in-vivo human blood flow data. Both data types were acquired under a controlled acquisition protocol developed to minimize the distortion of the color Doppler data and hence to simplify the phase-unwrapping task. In addition to the qualitative assessment of the results, a quantitative assessment approach was developed to measure the success of the results. The results of our new algorithm have been compared on ultrasound data to those from other well-known algorithms, and it outperforms all of them.

  2. Sensitivity evaluation of DSA-based parametric imaging using Doppler ultrasound in neurovascular phantoms

    NASA Astrophysics Data System (ADS)

    Balasubramoniam, A.; Bednarek, D. R.; Rudin, S.; Ionita, C. N.

    2016-03-01

    An evaluation of the relation between parametric imaging results obtained from Digital Subtraction Angiography (DSA) images and blood-flow velocity measured using Doppler ultrasound in patient-specific neurovascular phantoms is provided. A silicone neurovascular phantom containing internal carotid artery, middle cerebral artery and anterior communicating artery was embedded in a tissue equivalent gel. The gel prevented movement of the vessels when blood mimicking fluid was pumped through it to obtain Colour Doppler images. The phantom was connected to a peristaltic pump, simulating physiological flow conditions. To obtain the parametric images, water was pumped through the phantom at various flow rates (100, 120 and 160 ml/min) and 10 ml contrast boluses were injected. DSA images were obtained at 10 frames/sec from the Toshiba C-arm and DSA image sequences were input into LabVIEW software to get parametric maps from time-density curves. The parametric maps were compared with velocities determined by Doppler ultrasound at the internal carotid artery. The velocities measured by the Doppler ultrasound were 38, 48 and 65 cm/s for flow rates of 100, 120 and 160 ml/min, respectively. For the 20% increase in flow rate, the percentage change of blood velocity measured by Doppler ultrasound was 26.3%. Correspondingly, there was a 20% decrease of Bolus Arrival Time (BAT) and 14.3% decrease of Mean Transit Time (MTT), showing strong inverse correlation with Doppler measured velocity. The parametric imaging parameters are quite sensitive to velocity changes and are well correlated to the velocities measured by Doppler ultrasound.

  3. Ultrasound and colour Doppler in infantile subglottic haemangioma.

    PubMed

    Rossler, Leo; Rothoeft, T; Teig, N; Koerner-Rettberg, C; Deitmer, T; Rieger, C H L; Hamelmann, E

    2011-11-01

    Subglottic haemangioma causes progressive and life-threatening stridor, typically manifesting at age 2-3 months. Standard diagnosis is by laryngoscopy. Larynx sonography is rarely used but allows assessment of the presence and extension of a mass that impinges on the subglottic airway. The additional use of colour Doppler enables demonstration of the vascular nature of such masses. To compare US and endoscopic findings in infants with subglottic haemangioma and to evaluate accuracy of US and colour Doppler imaging in this diagnosis. We report eight infants with subglottic haemangioma seen in our institution over the last decade. They presented with laryngeal stridor and were all investigated with both US and endoscopy. Six infants underwent colour Doppler sonography. US and endoscopic findings showed excellent anatomical correlation in lateral subglottic haemangioma. Colour Doppler imaging was deemed helpful in four infants. Larynx sonography with complementary colour Doppler imaging was non-invasive and helpful in the diagnosis of subglottic haemangioma.

  4. Parabola detection using matched filtering for ultrasound B-scans.

    PubMed

    Petcher, P A; Dixon, S

    2012-01-01

    Time of flight diffraction (ToFD) outputs B-scans using an ultrasound emitter and receiver at a constant separation, scanned over a sample surface parallel to the line between the transducers. The B-scan, with time and scan position axes, contains parabolic features characteristic of a point-like scatterer. Human vision effectively detects these shapes, but this is time consuming and requires training. A parabola matched filter has been developed that is simple to implement and transforms parabolic shapes to peaks whilst reducing noise in the scan. The scan can then be displayed as depth versus lateral position. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Common carotid artery pseudoaneurysm after neck dissection: colour Doppler ultrasound and multidetector computed tomography findings.

    PubMed

    Flor, N; Sardanelli, F; Ghilardi, G; Tentori, A; Franceschelli, G; Felisati, G; Cornalba, G P

    2007-05-01

    Common carotid artery pseudoaneurysm is a rare disease, which has been previously unreported in association with neck dissection. We describe the Doppler ultrasound and multidetector computed tomography (CT) findings of a case of carotid pseudoaneurysm, one month after pharyngolaryngectomy with bilateral neck dissection. Multidetector CT confirmed the diagnosis made on the basis of Doppler ultrasound; the high image quality of axial and three-dimensional reconstructions avoided the need for pre-operative conventional angiography. In the presence of a pulsatile cervical mass after neck surgery, pseudoaneurysm of the carotid artery should be included in the differential diagnosis, and multidetector CT can be the sole pre-operative diagnostic imaging modality.

  6. Enhanced Doppler ultrasound imaging of interstitial laser therapy in rat mammary tumors

    NASA Astrophysics Data System (ADS)

    Zasuly, James M.; Fan, Ming; Dowlatshahi, Kambiz

    1997-05-01

    In order to better develop ultrasonography for use in monitoring interstitial laser therapy (ILT), we imaged rat mammary tumors using power Doppler ultrasound in conduction with intravenous contrast agent (Albunex) before and after laser therapy. Small vessel perfusion throughout a variable portion of the tumor could be detected by power Doppler ultrasound. Lesions created with diode laser by delivery of 500 to 3000 J appeared as perfusion defects on post-treatment images. Image topography and lesion size correlated with gross histologic findings. We conclude that ultrasonographic monitoring of local changes in blood flow using contrast enhancing agent can be useful in characterizing lesions created with ILT.

  7. Effects of diagnostic levels of color Doppler ultrasound energy on the cell cycle of newborn rats.

    PubMed

    Zhu, J; Lin, J; Zhu, Z; Shou, W; Bi, D; Shi, L

    1999-04-01

    Our objective was to evaluate the safety of diagnostic levels of color Doppler ultrasound energy in the field of obstetrics and to provide the experimental data for its clinical application. After insonating pregnant rats with diagnostic levels of color Doppler ultrasound energy, we studied the cell cycles of the newborn rats by flow cytometry and factorial analysis. We found that the deoxyribonucleic acid content was not affected in any phase of the cell cycle in newborn rats by any of the different insonation times and frequencies.

  8. Investigation of a scanned cylindrical ultrasound system for breast hyperthermia.

    PubMed

    Ju, Kuen-Cheng; Tseng, Li-Te; Chen, Yung-Yaw; Lin, Win-Li

    2006-02-07

    This paper investigates the feasibility of a scanned cylindrical ultrasound system for producing uniform heating from the central to the superficial portions of the breast or localized heating within the breast at a specific location. The proposed system consists of plane ultrasound transducer(s) mounted on a scanned cylindrical support. The breast was immersed in water and surrounded by this system during the treatment. The control parameters considered are the size of the transducer, the ultrasound frequency, the scan angle and the shifting distance between the axes of the breast and the system. Three-dimensional acoustical and thermal models were used to calculate the temperature distribution. Non-perfused phantom experiments were performed to verify the simulation results. Simulation results indicate that high frequency ultrasound could be used for the superficial heating, and the scan angle of the transducer could be varied to obtain an appropriate high temperature region to cover the desired treatment region. Low frequency ultrasound could be used for deep heating and the high temperature region could be moved by shifting the system. In addition, a combination of low and high frequency ultrasound could result in a portion treatment from the central to the superficial breast or an entire breast treatment. Good agreement was obtained between non-perfused experiments and simulation results. The findings of this study can be used to determine the effects of the control parameters of this system, as well as to select the optimal parameters for a specific treatment.

  9. Doppler Scanning of Sediment Cores: A Useful Method for Studying Sedimentary Structures and Defining the Cutting Angle for Half Cores

    NASA Astrophysics Data System (ADS)

    Acar, Dursun; Cagatay, Namik; Biltekin, Demet; Eris, Kadir; Albut, Gulum; Ogretmen, Nazik; Arslan, Tugce; Sari, Erol

    2014-05-01

    We tested the doppler ultrasound scanning of sediment cores in PVC liners using 8 megahertz ultrasonic waves for detection of angular laminations. The method was tested with artificially prepared cores as well as marine and lake sediment cores, and proven to be a useful and fast technique for imaging and determining the vertical angularity of sedimentary structures, such as laminations and beddings. Random cutting axes provide two angularities on X and Y dimensions. In this study, the main scientific problem is 'sequential angular disconformity'. Importance of detection of these anomalies on whole cores before dividing into half cores based on determining the right cutting axes. Successful imaging was obtained from top three centimeter depth of the sediments below the PVC liner, using a linear Doppler probe. Other Doppler probes (e.g., convex probe) did not work for core scanning because of their wave-form and reflection characteristics. Longitudinal and rotational scanning with gap filler and ultrasonic wave conductive gel material for keeping energy range of wave is necessary for detecting the variation in the dip of the bedding and laminae in the cores before separation. Another angular reasoned problem is about horizontal surface and can be easily solved with adjustable position of sensor or ray source placement. Border of sampling points between two different lithology must be stay with regard to neighbour sediment angles. Vertical angularity correction is not easy and its effect on signal propagation, detection biases and effectible to mixed samples contamination during physical sampling (particle size analyzing). Determining the attitude of angled bedding before core splitting is important for further core analyses such as elemental analysis and digital X-ray radiography. After Doppler scanning, the splitting direction (i.e., vertical to bedding and lamination) can be determined. The method is cheap, quick and non- hazardous to health, unlike the x

  10. The effect of foot position on Power Doppler Ultrasound grading of Achilles enthesitis.

    PubMed

    Zappia, Marcello; Cuomo, Giovanna; Martino, Maria Teresa; Reginelli, Alfonso; Brunese, Luca

    2016-06-01

    The aim of this study was to determine whether foot position could modify power Doppler grading in evaluation of the Achilles enthesis. Eighteen patients with clinical Achilles enthesitis were studied with power Doppler ultrasound (PDUS) in five different positions of the foot: active and passive dorsiflexion, neutral position, active and passive plantar flexion. The Doppler signal was graded in any position and compared with the others. The Doppler signal was higher with the foot in plantar flexion and decreased gradually, sometimes till to disappear, while increasing dorsiflexion. The Doppler signal was always less during the active keeping of the position of the joint, than during the passive. The PDUS examination of the Achilles enthesis should be performed also with the foot in passive plantar flexion, in order not to underestimate the degree of vascularization.

  11. Acute Effects of Lateral Thigh Foam Rolling on Arterial Tissue Perfusion Determined by Spectral Doppler and Power Doppler Ultrasound.

    PubMed

    Hotfiel, Thilo; Swoboda, Bernd; Krinner, Sebastian; Grim, Casper; Engelhardt, Martin; Uder, Michael; Heiss, Rafael U

    2017-04-01

    Hotfiel, T, Swoboda, B, Krinner, S, Grim, C, Engelhardt, M, Uder, M, and Heiss, R. Acute effects of lateral thigh foam rolling on arterial tissue perfusion determined by spectral Doppler and power Doppler ultrasound. J Strength Cond Res 31(4): 893-900, 2017-Foam rolling has been developed as a popular intervention in training and rehabilitation. However, evidence on its effects on the cellular and physiological level is lacking. The aim of this study was to assess the effect of foam rolling on arterial blood flow of the lateral thigh. Twenty-one healthy participants (age, 25 ± 2 years; height, 177 ± 9 cm; body weight, 74 ± 9 kg) were recruited from the medical and sports faculty. Arterial tissue perfusion was determined by spectral Doppler and power Doppler ultrasound, represented as peak flow (Vmax), time average velocity maximum (TAMx), time average velocity mean (TAMn), and resistive index (RI), and with semiquantitative grading that was assessed by 4 blindfolded investigators. Measurement values were assessed under resting conditions and twice after foam rolling exercises of the lateral thigh (0 and 30 minutes after intervention). The trochanteric region, mid portion, and distal tibial insertion of the lateral thigh were representative for data analysis. Arterial blood flow of the lateral thigh increased significantly after foam rolling exercises compared with baseline (p ≤ 0.05). We detected a relative increase in Vmax of 73.6% (0 minutes) and 52.7% (30 minutes) (p < 0.001), in TAMx of 53.2% (p < 0.001) and 38.3% (p = 0.002), and in TAMn of 84.4% (p < 0.001) and 68.2% (p < 0.001). Semiquantitative power Doppler scores at all portions revealed increased average grading of 1.96 after intervention and 2.04 after 30 minutes compared with 0.75 at baseline. Our results may contribute to the understanding of local physiological reactions to self-myofascial release.

  12. The age-related advancement of arterial disease measured by Doppler ultrasound diastolic flow analysis.

    PubMed

    Terenzi, T; Gallagher, D; DeMeersman, R; Beadle, E; Muller, D

    1993-10-01

    To quantify by A-mode Doppler sonography the age-related progression of arterial disease so that age dependent normal values may be established for the screening Doppler peripheral arterial exam. Arterial distensibility was assessed by A-mode Doppler diastolic flow analysis as a measure of atherogenesis. These values will increase the sensitivity and decrease the incidence of false-positive results when the Doppler exam is utilized to differentially diagnosis vascular and sciatic neurogenic claudication. The relationship between age and results from the standard ankle/arm index ultrasound pneumatic cuff examination was also analyzed. A two by three analysis of variance with orthogonal Helmert contrast codes and simple linear regression analysis was utilized for this cross-sectionally designed investigation. The dependent measures of diastolic flow analysis and ankle/arm pressure index were obtained within three nested successively increasing age groups. Chiropractic office. Studied were a total of 90 sedentary nonsmoking subjects, aged 23-79 yr, all of whom had normally accepted levels of serum glucose, cholesterol and blood pressure. Subjects were screened for evidence of aortic coarctation, myocardial infarction, tachyarrhythmia, aortic valve stenosis, mitral prolapse, hypertension, hypercholesterolemia, diabetes and peripheral occlusive arterial disease. Anthropometric measurements and percent body fat were obtained. A predictive oxygen consumption bike ergometer test was performed to obtain aerobic capacity. The commonly utilized standard ankle/arm index ultrasound pneumatic cuff examination and arterial diastolic flow analysis were performed with A-mode Doppler ultrasound on all subjects. These results demonstrate that a significant inverse linear relationship exists between aging and arterial compliance (p < .0001) in our population. Diastolic flow analysis had a greater sensitivity to arterial disease than the standard ankle/arm index ultrasound pneumatic

  13. Technical Note: A new phantom design for routine testing of Doppler ultrasound.

    PubMed

    Grice, J V; Pickens, D R; Price, R R

    2016-07-01

    The objective of this project is to demonstrate the principle and operation for a simple, inexpensive, and highly portable Doppler ultrasound quality assurance (QA) phantom intended for routine QA testing. A prototype phantom has been designed, fabricated, and evaluated. The phantom described here is powered by gravity alone, requires no external equipment for operation, and produces a stable fluid velocity useful for quality assurance. Many commercially available Doppler ultrasound testing systems can suffer from issues such as a lengthy setup, prohibitive cost, nonportable size, or difficulty in use. This new phantom design aims to address some of these problems and create a phantom appropriate for assessing Doppler ultrasound stability. The phantom was fabricated using a 3D printer. The basic design of the phantom is to provide gravity-powered flow of a Doppler fluid between two reservoirs. The printed components were connected with latex tubing and then seated in a tissue mimicking gel. Spectral Doppler waveforms were sampled to evaluate variations in the data, and the phantom was evaluated using high frame rate video to find an alternate measure of mean fluid velocity flowing in the phantom. The current system design maintains stable flow from one reservoir to the other for approximately 7 s. Color Doppler imaging of the phantom was found to be qualitatively consistent with laminar flow. Using pulsed spectral Doppler, the average fluid velocity from a sample volume approximately centered in the synthetic vessel was measured to be 56 cm/s with a standard deviation of 3.2 cm/s across 118 measurements. An independent measure of the average fluid velocity was measured to be 51.9 cm/s with a standard deviation of 0.7 cm/s over 4 measurements. The developed phantom provides stable fluid flow useful for frequent clinical Doppler ultrasound testing and attempts to address several obstacles facing Doppler phantom testing. Such an ultrasound phantom can make routine

  14. FE6 during Sprint Ultrasound Scans

    NASA Image and Video Library

    2013-11-22

    ISS038-E-007119 (21 Nov. 2013) --- Japan Aerospace Exploration Agency astronaut Koichi Wakata, Expedition 38 flight engineer, wears ultrasound gear around his legs while performing the Integrated Resistance and Aerobic Training Study (Sprint) experiment in the Columbus laboratory of the International Space Station. Sprint evaluates the use of high intensity, low volume exercise training to minimize loss of muscle, bone, and cardiovascular function in station crew members during long-duration missions.

  15. Time-resolved volumetric MRI blood flow: a Doppler ultrasound perspective

    NASA Astrophysics Data System (ADS)

    van Pelt, Roy; Oliván Bescós, Javier; Nagel, Eike; Vilanova, Anna

    2014-03-01

    Hemodynamic information is increasingly inspected to assess cardiovascular disease. Abnormal blood-flow patterns include high-speed jet flow and regurgitant flow. Such pathological blood-flow patterns are nowadays mostly inspected by means of color Doppler ultrasound imaging. To date, Doppler ultrasound has been the prevailing modality for blood-flow analysis, providing non-invasive and cost-effective blood-flow imaging. Since recent years, magnetic resonance imaging (MRI) is increasingly employed to measure time-resolved blood-flow data. Albeit more expensive, MRI enables volumetric velocity encoding, providing true vector-valued data with less noise. Domain experts in the field of ultrasound and MRI have extensive experience in the interpretation of blood-flow information, although they employ different analysis techniques. We devise a visualization framework that extends on common Doppler ultrasound visualizations, exploiting the added value of MRI velocity data, and aiming for synergy between the domain experts. Our framework enables experts to explore the advantages and disadvantages of the current renditions of their imaging data. Furthermore, it facilitates the transition from conventional Doppler ultrasound images to present-day high-dimensional velocity fields. To this end, we present a virtual probe that enables direct exploration of MRI-acquired blood-flow velocity data using user-friendly interactions. Based on the probe, Doppler ultrasound inspired visualizations convey both in-plane and through-plane blood-flow velocities. In a compound view, these two-dimensional visualizations are linked to state-of-the-art three-dimensional blood-flow visualizations. Additionally, we introduce a novel volume rendering of the blood-flow velocity data that emphasizes anomalous blood-flow patterns. The visualization framework was evaluated by domain experts, and we present their feedback.

  16. Atypical Cerebral Lateralisation in Adults with Compensated Developmental Dyslexia Demonstrated Using Functional Transcranial Doppler Ultrasound

    ERIC Educational Resources Information Center

    Illingworth, Sarah; Bishop, Dorothy V. M.

    2009-01-01

    Functional transcranial Doppler ultrasound (fTCD) is a relatively new and non-invasive technique that assesses cerebral lateralisation through measurements of blood flow velocity in the middle cerebral arteries. In this study fTCD was used to compare functional asymmetry during a word generation task between a group of 30 dyslexic adults and a…

  17. Atypical Cerebral Lateralisation in Adults with Compensated Developmental Dyslexia Demonstrated Using Functional Transcranial Doppler Ultrasound

    ERIC Educational Resources Information Center

    Illingworth, Sarah; Bishop, Dorothy V. M.

    2009-01-01

    Functional transcranial Doppler ultrasound (fTCD) is a relatively new and non-invasive technique that assesses cerebral lateralisation through measurements of blood flow velocity in the middle cerebral arteries. In this study fTCD was used to compare functional asymmetry during a word generation task between a group of 30 dyslexic adults and a…

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

    PubMed

    Hwang, Ji Young

    2017-04-01

    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.

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

    PubMed Central

    2017-01-01

    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. PMID:28219004

  20. Remote Electromagnetic Vibration of Steerable Needles for Imaging in Power Doppler Ultrasound.

    PubMed

    Cabreros, Sarah S; Jimenez, Nina M; Greer, Joseph D; Adebar, Troy K; Okamura, Allison M

    2015-05-01

    Robotic needle steering systems for minimally invasive medical procedures require complementary medical imaging systems to track the needles in real time. Ultrasound is a promising imaging modality because it offers relatively low-cost, real-time imaging of the needle. Previous methods applied vibration to the base of the needle using a voice coil actuator, in order to make the needle visible in power Doppler ultrasound. We propose a new method for needle tip vibration, using electromagnetic actuation of small permanent magnets placed inside the needle to improve needle tip visibility in power Doppler imaging. Robotic needle insertion experiments using artificial tissue and ex vivo porcine liver showed that the electromagnetic tip vibration method can generate a stronger Doppler response compared to the previous base vibration method, resulting in better imaging at greater needle depth in tissue. It also eliminates previous issues with vibration damping along the shaft of the needle.

  1. Doppler ultrasound in the measurement of pulse wave velocity: agreement with the Complior method

    PubMed Central

    2011-01-01

    Aortic stiffness is an independent predictor factor for cardiovascular risk. Different methods for determining pulse wave velocity (PWV) are used, among which the most common are mechanical methods such as SphygmoCor or Complior, which require specific devices and are limited by technical difficulty in obtaining measurements. Doppler guided by 2D ultrasound is a good alternative to these methods. We studied 40 patients (29 male, aged 21 to 82 years) comparing the Complior method with Doppler. Agreement of both devices was high (R = 0.91, 0.84-0.95, 95% CI). The reproducibility analysis revealed no intra-nor interobserver differences. Based on these results, we conclude that Doppler ultrasound is a reliable and reproducible alternative to other established methods for the measurement of aortic PWV. PMID:21496271

  2. Remote Electromagnetic Vibration of Steerable Needles for Imaging in Power Doppler Ultrasound

    PubMed Central

    Cabreros, Sarah S.; Jimenez, Nina M.; Greer, Joseph D.; Adebar, Troy K.; Okamura, Allison M.

    2015-01-01

    Robotic needle steering systems for minimally invasive medical procedures require complementary medical imaging systems to track the needles in real time. Ultrasound is a promising imaging modality because it offers relatively low-cost, real-time imaging of the needle. Previous methods applied vibration to the base of the needle using a voice coil actuator, in order to make the needle visible in power Doppler ultrasound. We propose a new method for needle tip vibration, using electromagnetic actuation of small permanent magnets placed inside the needle to improve needle tip visibility in power Doppler imaging. Robotic needle insertion experiments using artificial tissue and ex vivo porcine liver showed that the electromagnetic tip vibration method can generate a stronger Doppler response compared to the previous base vibration method, resulting in better imaging at greater needle depth in tissue. It also eliminates previous issues with vibration damping along the shaft of the needle. PMID:26413379

  3. A computer simulation model for Doppler ultrasound signals from pulsatile blood flow in stenosed vessels.

    PubMed

    Gao, Lian; Zhang, Yufeng; Zhang, Kexin; Cai, Guanghui; Zhang, Junhua; Shi, Xinling

    2012-09-01

    A computer simulation model based on an analytic flow velocity distribution is proposed to generate Doppler ultrasound signals from pulsatile blood flow in the vessels with various stenosis degrees. The model takes into account the velocity field from pulsatile blood flow in the stenosed vessels, sample volume shape and acoustic factors that affect the Doppler signals. By analytically solving the Navier-Stokes equations, the velocity distributions of pulsatile blood flow in the vessels with various stenosis degrees are firstly calculated according to the velocity at the axis of the circular tube. Secondly, power spectral density (PSD) of the Doppler signals is estimated by summing the contribution of all scatterers passing through the sample volume grouped into elemental volumes. Finally, Doppler signals are generated using cosine-superposed components that are modulated by the PSD functions that vary over the cardiac cycle. The results show that the model generates Doppler blood flow signals with characteristics similar to those found in practice. It could be concluded that the proposed approach offers the advantages of computational simplicity and practicality for simulating Doppler ultrasound signals from pulsatile blood flow in stenosed vessels. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Spectrum of Doppler ultrasound signals from nonstationary blood flow.

    PubMed

    Bastos, C C; Fish, P J; Vaz, F

    1999-01-01

    A new formulation for the Doppler signal generation process in pulsatile flow has been developed enabling easier identification and quantification of the mechanisms involved in spectral broadening and the development of a simple estimation formula for the measured rms spectral width. The accuracy of the estimation formula was tested by comparing it with the spectral widths found by using conventional spectral estimation on simulated Doppler signals from pulsatile flow. The influence of acceleration, sample volume size, and time window duration on the Doppler spectral width was investigated for flow with blunt and parabolic velocity profiles passing through Gaussian-shaped sample volumes. Our results show that, for short duration windows, the spectral width is dominated by window broadening and that acceleration has a small effect on the spectral width. For long duration windows, the effect of acceleration must be taken into account. The size of the sample volume affects the spectral width of the Doppler signal in two ways: by intrinsic broadening and by the range of velocities passing through it. These effects act in opposite directions. The simple spectral width estimation formula was shown to have excellent agreement with widths calculated using the model and indicates the potential for correcting not only for window and nonstationarity broadening but also for intrinsic broadening.

  5. Doppler Frequency-Shift Compensated Photorefractive Interferometer for Ultrasound Detection on Objects in Motion

    NASA Astrophysics Data System (ADS)

    Campagne, B.; Blouin, A.; Néron, C.; Monchalin, J.-P.

    2003-03-01

    Two-wave mixing based interferometry has been demonstrated to be a powerful technique for non-contact, broadband and speckle insensitive measurements of the small surface displacements produced by ultrasonic waves propagating in an object. When the object is in rapid motion along the line-of-sight of the probing laser or when the laser beam is rapidly scanned on a wavy surface, the two-wave mixing photorefractive interferometer loses sensitivity to the point it could become useless. To circumvent the Doppler frequency-shift produced by this relative motion, we propose a dynamic compensation scheme. We report a particularly simple scheme to implement this concept by monitoring the low-frequency output signal of a balanced two-wave mixing demodulator whose output is proportional to the frequency difference between the pump and signal beams, and feeding this signal back to the acousto-optic shifter. With this new concept, the two-wave mixing interferometer can operate on objects in rapid motion while maintaining its sensitivity to low frequency ultrasound.

  6. Ultrasound scanning of the acute abdomen by surgeons in training.

    PubMed Central

    Williams, R. J.; Windsor, A. C.; Rosin, R. D.; Mann, D. V.; Crofton, M.

    1994-01-01

    Ultrasound is widely used in the investigation of abdominal symptoms. Its increasing popularity may lead to pressure on radiological services, diagnostic delay and prolonged hospital stay. Immediate imaging performed by radiologists can contribute useful information in acute emergencies. This study assessed the accuracy and value of abdominal ultrasonography when carried out by admitting surgeons. Three surgical registrars were first instructed for two half days by a consultant radiologist. Patients with acute symptoms were scanned at the time of initial presentation using an Aloka SSD-620 scanner with 3.5 and 5 MHz probes. A total of 205 scans was performed--124 of the upper and 81 of the lower abdomen. Immediate ultrasound provided information that contributed to the establishment or refutal of a diagnosis in 138 patients (67.3%), predominantly by confirming or excluding hepatobiliary disease, tubo-ovarian pathology or aortic aneurysms and in blunt abdominal trauma. The diagnosis was altered in a small proportion (7.8%). Scanning proved unhelpful in 62 patients and misleading in five. Findings concurred with those of a radiologist in 86% of the 139 patients subsequently scanned. Abdominal ultrasound is a useful tool in the hands of surgeons dealing with emergencies and may occasionally provide vital information. If access to radiological facilities is delayed, ultrasound by the admitting surgeon could lead to improved patient management and cost savings. PMID:8074382

  7. Ventricular septal defect after myocardial infarction: assessment by cross sectional echocardiography with pulsed wave Doppler scanning.

    PubMed Central

    MacLeod, D; Fananapazir, L; de Bono, D; Bloomfield, P

    1987-01-01

    Eight patients who developed a ventricular septal defect after myocardial infarction were assessed by cross sectional echocardiography and pulsed wave Doppler scanning. Cross sectional echocardiography visualised the defect in four patients and gave an accurate assessment of global and regional left ventricular function in all eight. In all patients pulsed wave Doppler scanning detected turbulent flow at the apex of the right ventricle or adjacent to a wall motion abnormality affecting the interventricular septum. Pulsed wave Doppler detected coexisting mitral regurgitation in one patient and tricuspid regurgitation in another two. In all patients a left to right shunt was confirmed by oximetry and the location of the defect was identified by angiography or at operation or necropsy. Cross sectional echocardiography in combination with pulsed wave Doppler scanning is useful in the rapid bedside evaluation of patients with ventricular septal defect after myocardial infarction. Images Fig PMID:3663420

  8. Direct and Doppler angle-independent measurement of blood flow velocity in small-diameter vessels using ultrasound microbubbles.

    PubMed

    Roy, Homagni Sikha; Zuo, Guoqing; Luo, Zhengchun; Wu, Hanping; Krupka, Tianyi M; Ran, Haitao; Li, Pan; Sun, Youping; Wang, Zhigang; Zheng, Yuanyi

    2012-01-01

    This article represents an initial attempt to demonstrate the feasibility of a novel method for measuring flow velocity in small vessels, which is a direct, noninvasive, ultrasound-guided, and Doppler angle-independent method. In vitro, experiments were designed to mimic blood flow inside tubes. Harmonic ultrasound imaging was used to track the movement of microbubbles, and the mean flow velocity was calculated. In vivo, the flow velocities were measured in the central arteries of rabbit ears. This method can be used whenever the Doppler ultrasound cannot measure the velocity in small vessels because of either low sensitivity or Doppler angle limitation. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Doppler ultrasound spectral enhancement using the Gabor transform-based spectral subtraction.

    PubMed

    Zhang, Yu; Zhang, Hong

    2005-10-01

    Most of the important clinical indices of blood flow are estimated from the spectrograms of Doppler ultrasound (US) signals. Any noise may degrade the readability of the spectrogram and the precision of the clinical indiCes, so the spectral enhancement plays an important role in Doppler US signal processing. A new Doppler US spectral enhancement method is proposed in this paper and implemented in three main steps: the Gabor transform is used to compute the Gabor coefficients of a Doppler US signal, the spectral subtraction is performed on the magnitude of the Gabor coefficients, and the Gabor expansion with the spectral subtracted Gabor coefficients is used to reconstruct the denoised Doppler US signal. The different analysis and synthesis windows are examined in the Gabor transform and expansion. The signal-to-noise ratio (SNR) improvement together with the overall enhancement of spectrograms are examined on the simulated Doppler US signals from a femoral artery. The results show the denoising method based on the orthogonal-like Gabor expansion achieves the best denoising performance. The experiments on some clinical Doppler US signals from umbilical arteries confirm the superior denoising performance of the new method.

  10. The role of Doppler ultrasound in rheumatic diseases.

    PubMed

    Porta, Francesco; Radunovic, Goran; Vlad, Violeta; Micu, Mihaela C; Nestorova, Rodina; Petranova, Tzvetanka; Iagnocco, Annamaria

    2012-06-01

    The use of Doppler techniques, including power, colour and spectral Doppler, has greatly increased in rheumatology in recent years. This is due to the ability of Doppler US (DUS) to detect pathological vascularization within joints and periarticular soft tissues, thereby demonstrating the presence of active inflammation, which has been reported to be correlated with the local neo-angiogenesis. In synovitis, DUS showed a high correlation with histological and MRI findings, thus it is considered a valid tool to detect pathological synovial vascularization. Moreover, it is more sensitive than clinical examination in detecting active joint inflammation and in the evaluation of response to treatment. In addition, DUS may be considered as a reference imaging modality in the assessment of enthesitis, MRI being not sensitive and histology not feasible. Moreover, it has been demonstrated to be able to detect changes in asymptomatic enthesis. In conclusion, DUS is a useful and sensitive tool in the evaluation and monitoring of active inflammation. Its widespread use in clinical rheumatological practice is recommended. The aim of this article is to review the current literature about the role of DUS in rheumatic diseases, analysing its validity, reliability and feasibility.

  11. Use of power Doppler ultrasound-guided biopsies to locate regions of tumour hypoxia.

    PubMed Central

    Evans, S. M.; Laughlin, K. M.; Pugh, C. R.; Sehgal, C. M.; Saunders, H. M.

    1997-01-01

    The purpose of this study was to determine whether power Doppler ultrasound techniques could be used to direct biopsies into tumour regions with relatively low red blood cell flux, and therefore preferentially sample regions that were relatively hypoxic. Subcutaneous 9L glioma rat tumours were biopsied using power Doppler ultrasound guidance. Immunohistochemical detection of the 2-nitroimidazole EF5 was performed to determine the presence and level of hypoxia in the biopsy samples. Comparisons between the power Doppler-determined red blood cell flux and EF5 binding were made. In seven out of eight tumours studied, power Doppler ultrasound allowed differentiation of a relatively hypoxic region from a relatively oxic region by localizing relatively low vs high red blood cell flux areas respectively. In one of these seven tumours, RBC flux was high in both biopsied sites and hypoxia was not present in either. In two of these seven tumours, hypoxia was present in each biopsy and both of the red blood cell flux measurements were low. In the eighth tumour, both the EF5 binding and the red blood cell flux measurements were low. In this tumour, low EF5 binding was due to the dominance of necrotic cells, which will not reduce or bind EF5 in the biopsy specimen. Using EF5-binding techniques, we have confirmed that regions of relatively low red blood cell flux are more hypoxic than those with relatively high red blood cell flux. Counterstaining specimens with haematoxylin and eosin allows differentiation of low EF5-binding regions due to oxia vs necrosis. These methods have clinical implications for the expanded use of power Doppler ultrasound as a means to direct tissue sampling when it is important to identify the presence of hypoxia. Images Figure 1 Figure 2 Figure 4 Figure 5 PMID:9374376

  12. Magnetic resonance imaging of the placenta identifies placental vascular abnormalities independently of Doppler ultrasound.

    PubMed

    Messerschmidt, A; Baschat, A; Linduska, N; Kasprian, G; Brugger, P C; Bauer, A; Weber, M; Prayer, D

    2011-06-01

    To evaluate the relationship between placental vascular pathology detected by prenatal magnetic resonance imaging (MRI) and perinatal outcome. This was a retrospective, hospital-based, cross-sectional study in which all fetal MRI examinations of singleton pregnancies with vascular placental pathology (i.e. infarction with/without hemorrhage, subchorionic thrombi/hemorrhages, intervillous thrombi/hemorrhages, or retroplacental hematoma) in the period 2002-2007 were included. The extent of the pathology was expressed as a percentage of the total placental volume. Abnormalities of umbilical artery Doppler ultrasound examinations within 7 days between MRI and ultrasound examination were noted. Death in utero or postnatally was the primary outcome. Gestational age at MRI and at birth and the occurrence of intrauterine growth restriction (IUGR) were noted. Logistic regression analysis was performed to assess the impact of gestational age at MRI, extent of the vascular lesion and presence of pathological Doppler ultrasound measurements on the prediction of mortality. Fifty-nine structurally normal singleton pregnancies with placental vascular abnormalities were included in the analysis. Mortality rate was 36%; among the survivors, 87% were born before 37 + 0 gestational weeks and 50% suffered from IUGR. In 55% of the pregnancies pathological umbilical artery Doppler findings were identified, of which 27% were non-survivors. Mortality was predicted by earlier gestational age at fetal MRI for placental pathology (P < 0.05) and increasing extent of the vascular lesion (P < 0.05), but not by the presence of pathological Doppler ultrasound data. Accuracy of the prediction was 82%, sensitivity was 67% and specificity 89%. MRI-detected vascular placental pathologies may help to identify pregnancies at risk for adverse outcome and fetal death independently of umbilical artery Doppler status. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.

  13. Cerebral blood flow in the newborn infant: comparison of Doppler ultrasound and /sup 133/xenon clearance

    SciTech Connect

    Greisen, G.; Johansen, K.; Ellison, P.H.; Fredriksen, P.S.; Mali, J.; Friis-Hansen, B.

    1984-03-01

    Two techniques of Doppler ultrasound examination, continuous-wave and range-gated, applied to the anterior cerebral artery and to the internal carotid artery, were compared with /sup 133/xenon clearance after intravenous injection. Thirty-two sets of measurements were obtained in 16 newborn infants. The pulsatility index, the mean flow velocity, and the end-diastolic flow velocity were read from the Doppler recordings. Mean cerebral blood flow was estimated from the /sup 133/Xe clearance curves. The correlation coefficients between the Doppler and the /sup 133/Xe measurements ranged from 0.41 to 0.82. In the subset of 16 first measurements in each infant, there were no statistically significant differences between the correlation coefficients of the various Doppler ultrasound variables, but the correlation coefficients were consistently lower for the pulsatility index than for mean flow velocity or end-diastolic flow velocity, and they were consistently higher for the range-gated than for the continuous-wave Doppler technique.

  14. Preoperative imaging for DIEA perforator flaps: a comparative study of computed tomographic angiography and Doppler ultrasound.

    PubMed

    Rozen, Warren M; Phillips, Timothy J; Ashton, Mark W; Stella, Damien L; Gibson, Robert N; Taylor, G Ian

    2008-01-01

    Abdominal donor-site flaps, including the transverse rectus abdominis musculocutaneous (TRAM) and deep inferior epigastric artery (DIEA) perforator flaps, are standard in autologous breast reconstruction. With significant variation in the vascular anatomy of the abdominal wall, preoperative imaging is essential for preoperative planning and reducing intraoperative error. Doppler and color duplex sonography have been used with varying results, and the quest continues for optimal preoperative assessment. Computed tomographic angiography has recently been proposed as a noninvasive modality for this purpose. This is the first study to formally compare preoperative Doppler ultrasound with computed tomographic angiography for imaging the DIEA. Eight consecutive patients undergoing DIEA perforator flap surgery for breast reconstruction underwent both computed tomographic angiography and Doppler ultrasound preoperatively. All investigations and procedures were performed at the same institution with the same primary and assisting surgeons and the same radiology team. Computed tomographic angiography was superior to Doppler ultrasound at identifying the course of the DIEA and its branching pattern, and in visualizing its perforators. Preoperative computed tomographic angiography was highly specific (100 percent) and more sensitive in mapping and visualizing perforators (p = 0.0078). It was also proficient at identifying the superficial epigastric arterial system and for effectively displaying the results intraoperatively. It was substantially quicker and removed the interobserver error associated with Doppler ultrasonography. The study was ceased after eight patients because of the overwhelming benefit of computed tomographic angiography over Doppler ultrasonography. Computed tomographic angiography is a valuable imaging modality for the preoperative assessment of the donor-site vascular supply for TRAM and DIEA perforator flaps.

  15. Preoperative imaging for DIEA perforator flaps: a comparative study of computed tomographic angiography and doppler ultrasound.

    PubMed

    Rozen, Warren M; Phillips, Timothy J; Ashton, Mark W; Stella, Damien L; Gibson, Robert N; Taylor, G Ian

    2008-01-01

    Abdominal donor-site flaps, including the transverse rectus abdominis musculocutaneous (TRAM) and deep inferior epigastric artery (DIEA) perforator flaps, are standard in autologous breast reconstruction. With significant variation in the vascular anatomy of the abdominal wall, preoperative imaging is essential for preoperative planning and reducing intraoperative error. Doppler and color duplex sonography have been used with varying results, and the quest continues for optimal preoperative assessment. Computed tomographic angiography has recently been proposed as a noninvasive modality for this purpose. This is the first study to formally compare preoperative Doppler ultrasound with computed tomographic angiography for imaging the DIEA. Eight consecutive patients undergoing DIEA perforator flap surgery for breast reconstruction underwent both computed tomographic angiography and Doppler ultrasound preoperatively. All investigations and procedures were performed at the same institution with the same primary and assisting surgeons and the same radiology team. Computed tomographic angiography was superior to Doppler ultrasound at identifying the course of the DIEA and its branching pattern, and in visualizing its perforators. Preoperative computed tomographic angiography was highly specific (100 percent) and more sensitive in mapping and visualizing perforators (p = 0.0078). It was also proficient at identifying the superficial epigastric arterial system and for effectively displaying the results intraoperatively. It was substantially quicker and removed the interobserver error associated with Doppler ultrasonography. The study was ceased after eight patients because of the overwhelming benefit of computed tomographic angiography over Doppler ultrasonography. Computed tomographic angiography is a valuable imaging modality for the preoperative assessment of the donor-site vascular supply for TRAM and DIEA perforator flaps.

  16. Three-dimensional power Doppler ultrasound in cervical carcinoma: monitoring treatment response to radiotherapy.

    PubMed

    Huang, Y-F; Cheng, Y-M; Wu, Y-P; Chen, H H W; Hsu, K-F; Wu, Y-H; Chou, C-Y

    2013-07-01

    To investigate, using three-dimensional power Doppler ultrasound (3D-PDU), alterations in cervical intratumoral vascularization during and after radiotherapy. Between 2004 and 2009 we enrolled into the study 37 patients with FIGO Stages IB1-IIB cervical carcinoma who were undergoing radiotherapy. Serial 3D-PDU scans were performed during treatment, providing ultrasonographic measurement of tumor size, vascularization index, flow index and vascularization flow index, as well as monthly for 3 months post-treatment and tri-monthly thereafter, until vascularity was undetectable on two consecutive occasions. Physical examination, cervical cytology and serum marker evaluation were performed every 3-6 months for the first 5 years following treatment. Patients evaluated after a 2-year tumor-free interval and those with clinically assessed positive findings at follow-up underwent 3D-PDU to detect possible local disease. A total of 329 3D-PDU scans were performed in the 37 women. Cervical tumors and intratumoral vascularization disappeared within 3 months following radiotherapy, except in one patient with persistent disease. Nine patients had disease relapse, in four of whom the recurrence was local. In three of these four, there was recurrence of tumor and vascularization after a complete response. At follow-up, 3D-PDU detected local disease with 75.0% sensitivity and 98.5% specificity, while serum markers detected local disease among 34 patients with squamous cell carcinoma with 20.0% sensitivity and 77.3% specificity. Compared with serum markers in cervical squamous cell carcinoma, 3D-PDU has higher sensitivity and specificity for detecting local recurrence or persistence in cervical carcinoma. Thus, 3D-PDU combined with clinical assessment may be a new and safe method for monitoring radiotherapy treatment response and detecting local recurrence. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.

  17. Compound Doppler ultrasound signal simulation for pulsatile carotid arteries with a stenosis.

    PubMed

    Gao, Lian; Zhang, Yufeng; Zhou, Yi; Hu, Xiao; Deng, Li; Zhang, Kexin; Cai, Guanghui; Zhang, Junhua

    2016-08-12

    The simulated Doppler blood flow signals are widely used to assess the performance of the clutter filters for removing wall components while reserving low-velocity signals scattered from physiological blood flow approaching the inner vessel-wall injured by a stenosed lesion. By simultaneously taking into account the natural attributes of the Doppler equipment, blood flow as well as vessel wall of pulsatile carotid arteries with a stenosis, a computer simulation method is presented to produce the compound Doppler ultrasound blood flow signals. The in-phase and quadrature (I/Q) axial as well as radial blood flow signals are simulated by superposing a series of cosine functions regulated by the spectrograms estimated from the axial and radial velocity profiles firstly obtained through the solution of the incompressible Navier-Stokes equations, respectively. Meanwhile, the I/Q Doppler signals echoed from pulsatile near (anterior) and far (posterior) walls are reproduced based on their radial movements during a cardiac cycle. Ultimately, those confirmed quadrature signals are summed to generate the compound Doppler signals including the contribution from both blood flow and stenosed vessel-wall. The compound Doppler ultrasound signals echoed from both axial and radial blood flows as well as vessel walls with obstruction grades of 0% (normal arteries), 10% and 25% are simulated respectively. The real signals from the left carotid artery with an approximately 10% stenosis degree are also collected for further assessing the believability of simulated versions. The simulated and clinical tests demonstrate that the proposed computer simulation method can produce compound Doppler signals with confirmed qualitative and quantitative characteristics resembled with the clinical versions, which could be used as an theoretical data source for evaluating the performance of the signal separation between pulsatile blood flows and vessel walls with mild stenosed-lesions.

  18. Measurement of liver volumes by portal vein flow by Doppler ultrasound in living donor liver transplantation.

    PubMed

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

    2017-09-01

    The accurate estimation of liver volume and right/left ratio in donor candidates is critical, but there is no method using portal vein (PV) flow. Of 125 donor candidates, right/left liver volume ratio was estimated using ultrasound (US)-PV area ratio and Doppler US-PV flow ratio, and the results were compared with CT volumetry. We analyzed these results in 76 donors who underwent hemihepatectomy. We evaluated diagnostic values of Doppler US-PV flow for <30% remnant liver volume high-risk donors, and compared liver volume by Doppler US-PV flow with actual graft weight. In 125 donor candidates, 96.8% showed <10% difference between liver volume ratio by Doppler US-PV flow ratio and CT volumetry. Compared with CT volumetry, the mean percentage difference of liver volume ratio by Doppler US-PV flow ratio was significantly smaller than that by US-PV area ratio (±0.7% vs ±6.3%, P<.001). In 76 donors who underwent hemihepatctomy, results were similar, showing smaller mean percentage difference of liver volume ratio by Doppler US-PV flow ratio than that by US-PV area ratio (±1.0% vs ±6.0%, P<.001). Sensitivity and specificity for <30% remnant liver volume donors were 76.9% and 76.8%. Blood-free liver volume by Doppler US-PV flow was linearly correlated with graft weight (R(2) =0.770, P<.001), although significantly different, with 8.5% error ratio (669.3±173.2 vs 633.7±187.1, P=.001). Doppler US-PV flow can effectively estimate right/left liver volume ratio in initial donor investigation. However, Doppler US-PV flow is not accurate in assessing donors with <30% remnant liver volume and in estimating actual graft weight. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Duplex Doppler ultrasound study of the temporomandibular joint.

    PubMed

    Stagnitti, A; Marini, A; Impara, L; Drudi, F M; Lo Mele, L; Lillo Odoardi, G

    2012-06-01

    Sommario INTRODUZIONE: La fisiologia articolare dell’articolazione temporo-mandibolare (ATM) può essere esaminata sia dal punto di vista clinico che strumentale. La diagnostica per immagini ha da tempo contribuito con la risonanza magnetica (RM) e anche con la radiografia (Rx) e la tomografia computerizzata (TC) all’analisi della morfologia dei capi articolari e della cinetica condilare. L’esame duplex-ecodoppler è una metodica di largo impiego nello studio delle strutture in movimento in particolar modo a livello delle strutture del sistema vascolare. MATERIALI E METODI: È stata utilizzata un’apparecchiatura Toshiba APLIO SSA-770A, con l’uso di tecnica duplex-ecodoppler multi display, che consente la visualizzazione contemporanea dell’immagine ecografica e dei segnali Doppler utilizzando una sonda lineare del tipo phased array con cristalli trasduttori funzionanti ad una frequenza fondamentale di 6 MHz per gli spettri Doppler pulsati e 7.5 MHz per l’imaging ecografico. Sono stati esaminati nel Dipartimento di Scienze Radiologiche, Oncologiche e Anatomo-patologiche dell’Università “Sapienza” di Roma, 30 pazienti del reparto di Ortognatodonzia dell’Istituto di Odontoiatria della stessa Università. RISULTATI: Nei pazienti normali si è ottenuta un’alternanza regolare degli spettri Doppler, mentre nei soggetti con disfunzioni del complesso condilo-meniscale, si è persa la regolarità della sommatoria degli spettri di Fourier, con altezze incostanti in relazione a spostamenti irregolari del complesso condilo-meniscale. CONCLUSIONI: L’esame ecodoppler si è dimostrato, in tutti i pazienti, capace di discriminare quelli normali dai patologici e tra questi ultimi ha permesso di identificare gli aspetti più significativi delle patologie disfunzionali.

  20. Erectile dysfunction: the role of penile Doppler ultrasound in diagnosis.

    PubMed

    Halls, James; Bydawell, Gareth; Patel, Uday

    2009-11-01

    Erectile dysfunction (ED) is a common and debilitating condition with physical, psychological, and pharmacological aetiologies. The physical causes can be divided into problems with arterial inflow, structural penile abnormalities, or problems with the venous occlusion mechanism. Penile Doppler sonography is a specialized technique requiring a thorough knowledge of the topic in order to aid diagnosis and direct subsequent treatment. This technique is indicated in those patients with erectile dysfunction who do not respond to oral pharmacological agents (e.g., PDE-5 inhibitors). This pictorial essay will visit the anatomy and physiology of penile erection, the technique for performing the procedure, and review the imaging features for specific causes of ED.

  1. High frequency ultrasound with color Doppler in dermatology*

    PubMed Central

    Barcaui, Elisa de Oliveira; Carvalho, Antonio Carlos Pires; Lopes, Flavia Paiva Proença Lobo; Piñeiro-Maceira, Juan; Barcaui, Carlos Baptista

    2016-01-01

    Ultrasonography is a method of imaging that classically is used in dermatology to study changes in the hypoderma, as nodules and infectious and inflammatory processes. The introduction of high frequency and resolution equipments enabled the observation of superficial structures, allowing differentiation between skin layers and providing details for the analysis of the skin and its appendages. This paper aims to review the basic principles of high frequency ultrasound and its applications in different areas of dermatology. PMID:27438191

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

    PubMed

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

    2013-01-01

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

  3. Doppler ultrasound wall removal based on the spatial correlation of wavelet coefficients.

    PubMed

    Jin, Dawei; Wang, Yuanyuan

    2007-11-01

    In medical Doppler ultrasound systems, a high-pass filter is commonly used to reject echoes from the vessel wall. However, this leads to the loss of the information from the low velocity blood flow. Here a spatially selective noise filtration algorithm cooperating with a threshold denoising based on wavelets coefficients is applied to estimate the wall clutter. Then the blood flow signal is extracted by subtracting the wall clutter from the mixed signal. Experiments on computer simulated signals with various clutter-to-blood power ratios indicate that this method achieves a lower mean relative error of spectrum than the high-pass filtering and other two previously published separation methods based on the recursive principle component analysis and the irregular sampling and iterative reconstruction, respectively. The method also performs well when applied to in vivo carotid signals. All results suggest that this approach can be implemented as a clutter rejection filter in Doppler ultrasound instruments.

  4. Prediction of trabecular bone qualitative properties using scanning quantitative ultrasound

    PubMed Central

    Qin, Yi-Xian; Lin, Wei; Mittra, Erik; Xia, Yi; Cheng, Jiqi; Judex, Stefan; Rubin, Clint; Müller, Ralph

    2012-01-01

    Microgravity induced bone loss represents a critical health problem in astronauts, particularly occurred in weight-supporting skeleton, which leads to osteopenia and increase of fracture risk. Lack of suitable evaluation modality makes it difficult for monitoring skeletal status in long term space mission and increases potential risk of complication. Such disuse osteopenia and osteoporosis compromise trabecular bone density, and architectural and mechanical properties. While X-ray based imaging would not be practical in space, quantitative ultrasound may provide advantages to characterize bone density and strength through wave propagation in complex trabecular structure. This study used a scanning confocal acoustic diagnostic and navigation system (SCAN) to evaluate trabecular bone quality in 60 cubic trabecular samples harvested from adult sheep. Ultrasound image based SCAN measurements in structural and strength properties were validated by μCT and compressive mechanical testing. This result indicated a moderately strong negative correlations observed between broadband ultrasonic attenuation (BUA) and μCT-determined bone volume fraction (BV/TV, R2=0.53). Strong correlations were observed between ultrasound velocity (UV) and bone’s mechanical strength and structural parameters, i.e., bulk Young’s modulus (R2=0.67) and BV/TV (R2=0.85). The predictions for bone density and mechanical strength were significantly improved by using a linear combination of both BUA and UV, yielding R2=0.92 for BV/TV and R2=0.71 for bulk Young’s modulus. These results imply that quantitative ultrasound can characterize trabecular structural and mechanical properties through measurements of particular ultrasound parameters, and potentially provide an excellent estimation for bone’s structural integrity. PMID:23976803

  5. Prediction of trabecular bone qualitative properties using scanning quantitative ultrasound.

    PubMed

    Qin, Yi-Xian; Lin, Wei; Mittra, Erik; Xia, Yi; Cheng, Jiqi; Judex, Stefan; Rubin, Clint; Müller, Ralph

    2013-11-01

    Microgravity induced bone loss represents a critical health problem in astronauts, particularly occurred in weight-supporting skeleton, which leads to osteopenia and increase of fracture risk. Lack of suitable evaluation modality makes it difficult for monitoring skeletal status in long term space mission and increases potential risk of complication. Such disuse osteopenia and osteoporosis compromise trabecular bone density, and architectural and mechanical properties. While X-ray based imaging would not be practical in space, quantitative ultrasound may provide advantages to characterize bone density and strength through wave propagation in complex trabecular structure. This study used a scanning confocal acoustic diagnostic and navigation system (SCAN) to evaluate trabecular bone quality in 60 cubic trabecular samples harvested from adult sheep. Ultrasound image based SCAN measurements in structural and strength properties were validated by μCT and compressive mechanical testing. This result indicated a moderately strong negative correlations observed between broadband ultrasonic attenuation (BUA) and μCT-determined bone volume fraction (BV/TV, R(2)=0.53). Strong correlations were observed between ultrasound velocity (UV) and bone's mechanical strength and structural parameters, i.e., bulk Young's modulus (R(2)=0.67) and BV/TV (R(2)=0.85). The predictions for bone density and mechanical strength were significantly improved by using a linear combination of both BUA and UV, yielding R(2)=0.92 for BV/TV and R(2)=0.71 for bulk Young's modulus. These results imply that quantitative ultrasound can characterize trabecular structural and mechanical properties through measurements of particular ultrasound parameters, and potentially provide an excellent estimation for bone's structural integrity.

  6. Prediction of trabecular bone qualitative properties using scanning quantitative ultrasound

    NASA Astrophysics Data System (ADS)

    Qin, Yi-Xian; Lin, Wei; Mittra, Erik; Xia, Yi; Cheng, Jiqi; Judex, Stefan; Rubin, Clint; Müller, Ralph

    2013-11-01

    Microgravity induced bone loss represents a critical health problem in astronauts, particularly occurred in weight-supporting skeleton, which leads to osteopenia and increase of fracture risk. Lack of suitable evaluation modality makes it difficult for monitoring skeletal status in long term space mission and increases potential risk of complication. Such disuse osteopenia and osteoporosis compromise trabecular bone density, and architectural and mechanical properties. While X-ray based imaging would not be practical in space, quantitative ultrasound may provide advantages to characterize bone density and strength through wave propagation in complex trabecular structure. This study used a scanning confocal acoustic diagnostic and navigation system (SCAN) to evaluate trabecular bone quality in 60 cubic trabecular samples harvested from adult sheep. Ultrasound image based SCAN measurements in structural and strength properties were validated by μCT and compressive mechanical testing. This result indicated a moderately strong negative correlations observed between broadband ultrasonic attenuation (BUA) and μCT-determined bone volume fraction (BV/TV, R2=0.53). Strong correlations were observed between ultrasound velocity (UV) and bone's mechanical strength and structural parameters, i.e., bulk Young's modulus (R2=0.67) and BV/TV (R2=0.85). The predictions for bone density and mechanical strength were significantly improved by using a linear combination of both BUA and UV, yielding R2=0.92 for BV/TV and R2=0.71 for bulk Young's modulus. These results imply that quantitative ultrasound can characterize trabecular structural and mechanical properties through measurements of particular ultrasound parameters, and potentially provide an excellent estimation for bone's structural integrity.

  7. A real-time device for converting Doppler ultrasound audio signals into fluid flow velocity.

    PubMed

    Herr, Michael D; Hogeman, Cynthia S; Koch, Dennis W; Krishnan, Anandi; Momen, Afsana; Leuenberger, Urs A

    2010-05-01

    A Doppler signal converter has been developed to facilitate cardiovascular and exercise physiology research. This device directly converts audio signals from a clinical Doppler ultrasound imaging system into a real-time analog signal that accurately represents blood flow velocity and is easily recorded by any standard data acquisition system. This real-time flow velocity signal, when simultaneously recorded with other physiological signals of interest, permits the observation of transient flow response to experimental interventions in a manner not possible when using standard Doppler imaging devices. This converted flow velocity signal also permits a more robust and less subjective analysis of data in a fraction of the time required by previous analytic methods. This signal converter provides this capability inexpensively and requires no modification of either the imaging or data acquisition system.

  8. Embedded System for Real-Time Digital Processing of Medical Ultrasound Doppler Signals

    NASA Astrophysics Data System (ADS)

    Ricci, S.; Dallai, A.; Boni, E.; Bassi, L.; Guidi, F.; Cellai, A.; Tortoli, P.

    2008-12-01

    Ultrasound (US) Doppler systems are routinely used for the diagnosis of cardiovascular diseases. Depending on the application, either single tone bursts or more complex waveforms are periodically transmitted throughout a piezoelectric transducer towards the region of interest. Extraction of Doppler information from echoes backscattered from moving blood cells typically involves coherent demodulation and matched filtering of the received signal, followed by a suitable processing module. In this paper, we present an embedded Doppler US system which has been designed as open research platform, programmable according to a variety of strategies in both transmission and reception. By suitably sharing the processing tasks between a state-of-the-art FGPA and a DSP, the system can be used in several medical US applications. As reference examples, the detection of microemboli in cerebral circulation and the measurement of wall _distension_ in carotid arteries are finally presented.

  9. [Diagnosis of uterine vascular malformation using Doppler ultrasound].

    PubMed

    Deckner, C; Schiesser, M; Bastert, G

    2004-04-01

    We present the case of a 56-year-old woman, who was admitted to our clinic for diagnostic laparoscopy because of a cystic uterine tumour of uncertain dignity. In the patient's history three curettages due to recurrent acyclic premenopausal vaginal bleeding were reported without specific histological findings. The preceding MRI described the structure as a myoma. During preoperative diagnostics an arteriovenous malformation was suspected by transvaginal Doppler sonography. Consequently the procedure was changed and a laparotomy performed. The sonographic findings were confirmed during surgery and by histological examination. This case points out the important role of transvaginal sonography combined with colour-flow-mapping. By confirming the diagnosis preoperatively and changing the management a low-risk procedure could be ensured.

  10. Color-Doppler ultrasound in the diagnosis of oral vascular anomalies.

    PubMed

    Gianfranco, Gaimari; Eloisa, Fioravanti; Vito, Cantisani; Raffaele, Guerrisi; Gianluca, Tenore; Umberto, Romeo

    2014-01-01

    In last few years, thanks to laser technology with minimally invasive approach, there was a growing need for treatment of oral vascular malformations inside the dental offices. Generally, the diagnosis of oral vascular malformations is based on clinical history, clinical examination and imaging exams. In the present paper, we review, researching by PubMed, the technical aspects, clinical indications, potentialities and limitations of color-Doppler ultrasound in the work-up of oral vascular malformations. Different imaging modalities are encountered for the diagnosis and follow-up of these lesions such as computed tomography, magnetic resonance imaging, color-Doppler ultrasound and angiography. To date, color-Doppler ultrasound is considered the first-line imaging approach since it provides a non-invasive, cost effective, real time evaluation of oral vascular anomalies. It provides both morphological and vascular information, which are useful to determine the best therapeutic options. Ultrasonography, for these reasons, could be considered as a valuable diagnostic tool in the preliminary assessment of oral vascular anomalies.

  11. Color-Doppler Ultrasound in the Diagnosis of Oral Vascular Anomalies

    PubMed Central

    Gianfranco, Gaimari; Eloisa, Fioravanti; Vito, Cantisani; Raffaele, Guerrisi; Gianluca, Tenore; Umberto, Romeo

    2014-01-01

    In last few years, thanks to laser technology with minimally invasive approach, there was a growing need for treatment of oral vascular malformations inside the dental offices. Generally, the diagnosis of oral vascular malformations is based on clinical history, clinical examination and imaging exams. In the present paper, we review, researching by PubMed, the technical aspects, clinical indications, potentialities and limitations of color-Doppler ultrasound in the work-up of oral vascular malformations. Different imaging modalities are encountered for the diagnosis and follow-up of these lesions such as computed tomography, magnetic resonance imaging, color-Doppler ultrasound and angiography. To date, color-Doppler ultrasound is considered the first-line imaging approach since it provides a non-invasive, cost effective, real time evaluation of oral vascular anomalies. It provides both morphological and vascular information, which are useful to determine the best therapeutic options. Ultrasonography, for these reasons, could be considered as a valuable diagnostic tool in the preliminary assessment of oral vascular anomalies. PMID:24678469

  12. Quantitative investigation of in vitro flow using three-dimensional colour Doppler ultrasound.

    PubMed

    Guo, Z; Moreau, M; Rickey, D W; Picot, P A; Fenster, A

    1995-01-01

    A quantitative in vitro flow study was performed by using a three-dimensional colour Doppler imaging system. This system was based on a clinical ultrasound instrument with its transducer mounted on a motor-driven translation stage. A vascular and tissue-mimicking phantom containing two wall-less vessels, one normal and another stenotic, was used to quantify the measurement accuracy of the flow velocity and the flow field. Steady state flows, having Reynolds numbers ranging between 460 and 1300, were generated by a computer-controlled positive displacement pump. Effects of the parameter settings of the ultrasound instrument on results of the estimation of flow field were also studied. Experimental results show that our three-dimensional colour Doppler system's velocity accuracy was better than 7% of the Nyquist velocity and its spatial accuracy was better than 0.5 mm. The system showed a good correlation (r = 0.999) between the estimated and the true mean flow velocity, and a good correlation (r = 0.998) between the estimated maximum and the true mean flow velocity. This study is our first step toward validating the measurement of the three-dimensional velocity and wall shear stress distributions by using three-dimensional colour Doppler ultrasound

  13. Use of an ultrasound blood-mimicking fluid for Doppler investigations of turbulence in vitro.

    PubMed

    Thorne, Meghan L; Poepping, Tamie L; Rankin, Richard N; Steinman, David A; Holdsworth, David W

    2008-07-01

    Turbulence is an important factor in the assessment of stenotic disease and a possible causative mechanism for thromboembolism. Previous Doppler studies of turbulence have typically used whole-blood preparations or suspensions of erythrocytes. Recently, a water-glycerol based blood-mimicking fluid (BMF) has been developed for use in Doppler ultrasound studies. This fluid has desirable ultrasound properties but it has not previously been described during in vitro investigations of turbulence intensity. We report on investigations of grid-generated and constrained-jet turbulence in an in vitro test system. The BMF was found to generate significant levels of turbulence during steady flow at physiological flow rates, producing turbulent patterns in the distal region that were consistent with previous studies. Turbulence intensity increased significantly with flow rate (p < 0.005) for both the constrained jet and the constrained grid. Based on our observations, we conclude that a water-glycerol based BMF provides a suitable working fluid during in vitro investigations of turbulence using Doppler ultrasound.

  14. Preoperative color Doppler ultrasound assessment of the lateral thoracic artery perforator flap and its branching pattern.

    PubMed

    Tashiro, Kensuke; Harima, Mitsunobu; Mito, Daisuke; Shibata, Takashi; Furuya, Megumi; Kato, Motoi; Yamamoto, Takumi; Yamashita, Shuji; Narushima, Mitsunaga; Iida, Takuya; Koshima, Isao

    2015-06-01

    The anatomy of the lateral thoracic artery perforator flap remains controversial, but this region is extremely useful as a reconstructive donor site. In this report, we describe the usefulness of the preoperative color Doppler ultrasound evaluation for the harvesting of the lateral thoracic artery perforator flap, and we clarify its branching pattern. Twenty-seven patients underwent the preoperative color Doppler ultrasound assessment before perforator flaps were harvested. We evaluated the branching pattern and the diameter of the flaps by direct observation. All flaps were successfully transferred, and it was found that the branching pattern of the lateral thoracic perforator is divided into three groups: the superficial branch, the medial branch, and the deep branch. Their appearance ratios were 48.1% (13/27), 14.8% (4/27), and 81.5% (22/27), respectively. The lateral thoracic artery perforator flap has a great deal of anatomical variation, and vessels with relatively small diameters compared to those of other flaps. This is why flaps from this region are not currently popular. This study revealed the superiority of the color Doppler ultrasound for preoperative planning of the lateral thoracic artery perforator flap elevation. Furthermore, the branching pattern and the diameters of the different branches were specified.

  15. Regional cerebral blood flow estimates in newborn lamb using amplitude-mode color Doppler ultrasound.

    PubMed

    Taylor, G A

    1996-01-01

    To establish the feasibility of determining changes in regional cerebral blood flow using amplitude-mode color Doppler ultrasound in the newborn lamb. Regional cerebral blood flow was modified by intrastriatal injection of N -methyl-D-aspartic acid (NMDA) in two newborn lambs and compared with that in a control animal receiving only intrastriatal saline. Serial color Doppler ultrasound energy images were obtained in coronal projection at the level of the foramen of Monro, before and at 20, 40, and 60 min after NMDA or saline injection using a 7.0-MHz linear transducer. Real-time images were obtained and transferred onto a computer workstation. Regions of interest were drawn over each striatum and cerebral hemisphere and were analyzed for mean pixel intensity (MPI) at each interval. Paired regional cerebral blood flow (r-CBF) determinations (radiolabeled microsphere technique) were also obtained in every animal. MPI and r-CBF for each anatomic region were compared using linear regression. Mean color pixel intensities increased significantly in the ipsilateral basal ganglia and cerebral hemisphere (p < 0.0001) in both animals injected with NMDA, but not in the animal injected with normal saline (p < 0.63). A strong and significant linear correlation was found between MPI and r-CBF for striatum (r = 0.89, p < 0.0001) and cerebral hemisphere (r = 0.85, p < 0.0001). Amplitude-mode color Doppler ultrasound shows potential for technically simple determination of serial changes in regional cerebral blood flow in infants.

  16. Factors affecting color Doppler energy ultrasound recordings in an in-vitro model.

    PubMed

    Gudmundsson, S; Valentin, L; Pirhonen, J; Olofsson, P A; Dubiel, M; Marsal, K

    1998-07-01

    Compared to conventional color Doppler ultrasound imaging, the new color Doppler modality "color Doppler energy" (CDE) has improved the possibility of visualizing blood vessels having low blood-flow velocities, but appears to be influenced by the settings of the ultrasound instrument and motion artefacts. The aim of this methodological study was to evaluate the effects of the different factors on the CDE signal. The CDE mode of a commercially available ultrasound system (Acuson 128 XP) was tested in an in vitro study. The effect of depth, angle of insonation, flow velocity, instrument power output, gain and other instrument settings were evaluated. The CDE signals obtained were stored on videotape and subsequently subjected to off-line computer analysis. The CDE signal intensity was found to be influenced mainly by fluid flow velocity, but was also affected by depth and instrument settings. Gain and power had, however, limited influence in this setting. Thus, the intensity of the CDE signal is influenced by several factors. Our results emphasize the need for optimum fixed preinstalled instrument settings when attempting to quantify organ perfusion by use of this new technique.

  17. Activity of Crohn's disease assessed by colour Doppler ultrasound analysis of the affected loops.

    PubMed

    Esteban, J M; Maldonado, L; Sanchiz, V; Minguez, M; Benages, A

    2001-01-01

    The aim of this study was to evaluate with colour Doppler ultrasound the vascular changes in the wall of the loops affected by Crohn's disease, and to establish whether these changes reflects clinical or biochemical activity of Crohn's disease. Seventy-nine patients with Crohn's disease (44 with active disease and 35 inactive patients) were studied with frequency- and amplitude-encoded duplex Doppler sonography. A group of 35 healthy volunteers were also included. The exam consisted of the search for colour signals in the walls of the loops affected by Crohn's disease, classifying the degree of vascularity with a simple scoring system into three groups: absence of colour signal (score of 0); weak or scattered colour signals (score of 1); and multiple colour signals or clear identification of vessels in the loops walls (score of 2). Doppler curves were obtained of the detected vessels with measurement of the resistive index (RI). There was a visible increase in the gut walls' vascularity in the active patients compared with those with inactive disease. The mean RI was statistically significantly lower in the gut wall vessels of the patients with active illness than that obtained in the inactive patients. Colour Doppler ultrasound is a useful tool in the assessment of activity in Crohn's disease.

  18. Interactive realtime Doppler-ultrasound visualization of the heart.

    PubMed

    Heid, V; Evers, H; Henn, C; Glombitza, G; Meinzer, H P

    2000-01-01

    Heart valve insufficiencies can optimally be assessed using transesophageal, triggered, three-dimensional ultrasound imaging. The dynamic ultrasound data contain morphological as well as functional components which are recorded and displayed simultaneously. It allows the visualization of intracardiac motion which is an important parameter to detect abnormal flow caused by defect valves. A realtime reconstruction is desired to get a spatial impression on the one hand and to interactively clip parts of the volume on the other hand. Therefore, we use the OpenGL Volumizer API. Scalability of the visualization was tested with respect to different workstations and graphics resources using a Multipipe Utility library. The combination of both APIs enables a visualization of volumetric and functional data with frame rates up to 10 frames per second. By using the proposed method, it is possible to visualize the jet in the original color-coding which is employed during a conventional two-dimensional examination for displaying the velocity values. The morphological and the functional data are handled as two independent data channels. A good scalability from low cost up to high end graphic workstations is given by the use of the MPU. The quality of the resulting 3D images allows exact differentiation of heart valve insufficiencies to support the diagnostic procedure.

  19. Doppler ultrasound venous mapping of the lower limbs

    PubMed Central

    Galeandro, Aldo Innocente; Quistelli, Giovanni; Scicchitano, Pietro; Gesualdo, Michele; Zito, Annapaola; Caputo, Paola; Carbonara, Rosa; Galgano, Giuseppe; Ciciarello, Francesco; Mandolesi, Sandro; Franceschi, Claude; Ciccone, Marco Matteo

    2012-01-01

    Background The study aim was to test the accuracy (intra and interobserver variability), sensitivity, and specificity of a simplified noninvasive ultrasound methodology for mapping superficial and deep veins of the lower limbs. Methods 62 consecutive patients, aged 62 ± 11 years, were enrolled. All underwent US-examinations, performed by two different investigators, of both legs, four anatomical parts, and 17 veins, to assess the interobserver variability of evaluation of superficial and deep veins of the lower limbs. Results Overall the agreement between the second versus the first operator was very high in detecting reflux (sensitivity 97.9, specificity 99.7, accuracy 99.5; P = 0.80 at McNemar test). The higher CEAP classification stages were significantly associated with reflux (odds ratio: 1.778, 95% confidence interval: 1.552–2.038; P < 0.001) as well as with thrombosis (odds ratio: 2.765, 95% confidence interval: 1.741–4.389; P < 0.001). Thus, our findings show a strict association between the symptoms of venous disorders and ultrasound evaluation results for thrombosis or reflux. Conclusion This study demonstrated that our venous mapping protocol is a reliable method showing a very low interobserver variability, which makes it accurate and reproducible for the assessment of the morphofunctional status of the lower limb veins. PMID:22371652

  20. [Digital scanning converter for medical endoscopic ultrasound imaging].

    PubMed

    Chen, Xiaodong; Zhang, Hongxu; Zhou, Peifan; Wen, Shijie; Yu, Daoyin

    2009-02-01

    This paper mainly introduces the design of digital scanning converter (DSC) for medical endoscopic ultrasound imaging. Fast modified vector totational CORDIC (FMVR-CORDIC) arithmetic complete coordinate conversion is used to increase the speed of ultrasonic scanning imaging. FPGA is used as the kernel module to control data transferring, related circuits and relevant chips' working, and to accomplish data preprocessing. With the advantages of simple structure, nice flexibility and convenience, it satisfies the demand for real-time displaying in this system. Finally, the original polar coordinate image is transformed to rectangular coordinate grey image through coordinate transformation. The system performances have been validated by the experimental result.

  1. Lidar - ND Halo Scanning Doppler, Boardman - Raw Data

    DOE Data Explorer

    Leo, Laura

    2017-03-31

    The University of Notre Dame (ND) scanning lidar dataset used for the WFIP2 Campaign is provided. The raw dataset contains the radial velocity and backscatter measurements along with the beam location and other lidar parameters in the header.

  2. Pulse Doppler ultrasound as a tool for the diagnosis of chronic testicular dysfunction in stallions

    PubMed Central

    Ortiz-Rodriguez, Jose M.; Anel-Lopez, Luis; Martín-Muñoz, Patricia; Álvarez, Mercedes; Gaitskell-Phillips, Gemma; Anel, Luis; Rodríguez-Medina, Pedro; Peña, Fernando J.

    2017-01-01

    values (high vascular perfusion). In contrast, subfertile stallions tend to present high values of PI and RI (high vascular resistance). The ROC curves revealed that the best Doppler parameters to predict sperm quality in stallions were: Doppler velocities (PSV, EDV and TAMV), the diameter of the capsular artery and TABF parameters (tissue perfusion parameters). Cut off values were established using a Youden´s Index to identify fertile stallions from stallions with testicular dysfunction. Spectral Doppler ultrasound is a good predictive tool for sperm quality since correlations were determined among Doppler parameters and markers of sperm quality. Doppler ultrasonography could be a valuable diagnostic tool for use by clinical practitioners for the diagnosis of stallions with testicular dysfunction and could be a viable alternative to invasive procedures traditionally used for diagnosis of sub-fertility disorders. PMID:28558006

  3. Two-dimensional blood flow vectors obtained with bidirectional Doppler ultrasound.

    PubMed

    Masuno, Genta; Nagaoka, Ryo; Omori, Aiko; Ishikawa, Yasuo; Akagawa, Osamu; Arakawa, Mototaka; Saijo, Yoshifumi

    2014-01-01

    Precise measurement of blood flow is important because blood flow closely correlates formation of thrombus and atherosclerotic plaque. Among clinically applied modalities for blood flow measurement, color Doppler ultrasound shows two-dimensional (2D) distribution of one-dimensional blood flow component along the ultrasound beam. In the present study, 2D blood flow vector is obtained with high temporal and bidirectional Doppler ultrasound technique. Linear array probe with the central frequency of 7.5 MHz and an ultrasound data acquisition system with 128 transmit and 128 receive channels were equipped. Frame rate of 5 kHz was achieved by parallel receive beam forming with a wide transmitted wave. The flow velocity was measured from two different angles by beam steering. The interval of two measurements was 0.8 msec and it was considered as almost one moment to obtain 2D blood flow vector. B-mode image and 2D blood flow vector of the pulsatile flow in a carotid artery model showed small vortex at the bifurcation area. The method was also applied for visualization of in vivo blood flow vector in human carotid arteries. 2D blood flow measurement may predict the risk area of thrombus and plaque formation induced by abnormal blood flow.

  4. Color Doppler Ultrasound Study of Glomuvenous Malformations with its Clinical and Histologic Correlations.

    PubMed

    Wortsman, X; Millard, F; Aranibar, L

    2017-07-03

    Glomuvenous malformations are hamartomatous lesions characterized by the presence of glomus cells in the vascular smooth muscle. We present the clinical and color Doppler ultrasound features of a series of 13 cases of histologically confirmed glomuvenous malformations. In all cases, the ultrasound study revealed moderately delimited superficial dermal and hypodermal pseudonodular structures of mixed echogenicity, with hypoechoic and heterogeneous areas and anechoic, pseudocystic tubular and lacunar zones. Arterial and venous vessels, mainly with a low flow (≤ 15cm/s) were observed in 85% of patients, but no arteriovenous shunts were present. Deeper structures were not affected and no phleboliths were detected. The clinical and ultrasound findings could facilitate diagnosis, surgical planning, and noninvasive follow-up in these tumors. Copyright © 2017 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.

  5. Experimental characterization of a vector Doppler system based on a clinical ultrasound scanner.

    PubMed

    Eranki, Avinash; Sikdar, Siddhartha

    2009-01-01

    We have developed a vector Doppler system using a clinical ultrasound scanner with a research interface. In this system, vector Doppler estimation is performed by electronically dividing a linear array transducer into a transmit sub-aperture and two receive sub-apertures. The receive beams are electronically steered, and two velocity components are estimated from echoes received from the beam overlap region. The velocity vector is reconstructed from these two estimates. The goal of this study was to characterize this vector Doppler system in vitro using a string phantom with a pulsatile velocity waveform. We studied the effect of four parameters on the estimation error: beam steering angle, angle of the velocity vector, depth of the scatterer relative to the beam overlap region and the transmit focus depth. Our results show that changing these parameters have minimal effect on the velocity and angle estimates, and robust velocity vector estimates can be obtained under a variety of conditions. The mean velocity error was less than 0.06 x pulse repetition frequency. The velocity estimates are sensitive to the Doppler estimation method. Our results indicate that vector Doppler using a linear array transducer is feasible for a wide range of imaging parameters. Such a system would facilitate the investigation of complex blood flow and tissue motion in human subjects.

  6. Color Doppler Ultrasound in Diagnosis and Assessment of Carotid Body Tumors: Comparison with Computed Tomography Angiography.

    PubMed

    Jin, Zhan-Qiang; He, Wen; Wu, Dong-Fang; Lin, Mei-Ying; Jiang, Hua-Tang

    2016-09-01

    A carotid body tumor (CBT) is a rare, non-chromaffin paraganglioma, and its diagnosis mainly depends on imaging modalities. The aim of this study was to investigate the ability of color Doppler ultrasound (CDU) in the diagnosis and assessment of CBT based on computed tomography (CT). We retrospectively reviewed the CDU and CT features of 49 consecutive CBTs and 23 schwannomas from 67 patients and compared these findings with surgical resection specimens. The mean size of CBT lesions on ultrasound scans and CT angiography (CTA) was 3.24 cm ± 0.82 cm (range, 1.6-5.2 cm) and 3.84 cm ± 1.08 cm (range, 1.8-6.8 cm), respectively, which had statistically significant difference (t = 9.815, p = 0.000). The vascularity of CBT lesions was richer than that of schwannoma lesions (p < 0.05). Intra-lesional vascularities feeding CBT mostly arose from the external carotid artery and had spectrum characteristics including low velocity and resistance. Peak systolic velocity (PSV) and resistance index (RI) of the vasa vasorum were 39.8 cm/s ± 19.8 cm/s and 0.54 ± 0.06, respectively. There was the correlation between CTA and CDU in identifying Shamblin type I CBT lesions, while CTA technique was superior for CDU, identifying Shamblin type II and III CBT lesions. Accuracy, specificity and sensitivity of CDU in diagnosing CBTs were 87.5% (63 of 72), 82.6% (19 of 23) and 89.8% (44 of 49), respectively. Both accuracy and sensitivity of CTA in diagnosing CBTs were 100%. CDU can be useful for assessment of Shamblin's type and intra-lesional blood flow of CBTs before its metastases, while CT imaging can reveal the relationship between lesions and adjacent arteries, as well as the involvement of the skull base. CDU combined with CT imaging can be used as an optimal detection modality for the assessment and management of CBT.

  7. Combination of high-resolution and color Doppler ultrasound in diagnosis of carpal tunnel syndrome.

    PubMed

    Ghasemi-Esfe, Ahmad Reza; Khalilzadeh, Omid; Mazloumi, Mehdi; Vaziri-Bozorg, Seyed Mehran; Niri, Sanaz Ghaderi; Kahnouji, Hossein; Rahmani, Maryam

    2011-03-01

    Ultrasound has recently emerged as a diagnostic tool in carpal tunnel syndrome (CTS). To evaluate the utility of a combination of high-resolution and color Doppler ultrasound as an alternative to electrodiagnostic tests (EDT), in CTS diagnosis, and to define an ultrasonographic prediction model for CTS. A total of 85 patients with certain clinical diagnosis of CTS and 49 healthy controls were enrolled. High-resolution and color Doppler ultrasound were performed and the cross-sectional area (CSA), hypoechogenicity, and hypervascularity of the median nerve were evaluated. Receiver-operating characteristic curves were used to determine the optimal cut-off point of median nerve CSA in diagnosis of CTS. Multivariate logistic regression analysis was used to formulate a prediction model for CTS. The optimal cut-off point of median CSA in wrist was 10.5 mm(2). Hypervascularity (OR = 37.95), hypoechogenicity (OR = 12.30), and high CSA (OR = 34.79) of median nerve were significantly (P < 0.001) higher in CTS patients than in controls. No significant difference was found between the sensitivity and specificity of EDT and any of the above indices in prediction of CTS. An ultrasonographic model for prediction of CTS, comprised hypervascularity and/or high CSA of median nerve, could predict the CTS probability between 87-99%. The sensitivity and specificity of this model (86% and 84%) was not different from EDT (80% and 84%). A combination of high-resolution and color Doppler ultrasound can be used as a non-invasive alternative to EDT in diagnosis of CTS.

  8. Scanning laser Doppler Technique for velocity profile sensing on a moving surface.

    PubMed

    Sriram, P; Hanagud, S; Craig, J; Komerath, N M

    1990-06-01

    A scanning laser Doppler technique based on Chebyshev demodulation has been developed for the rapid measurement of spatially distributed velocity profiles. Scan frequencies up to 100 Hz can be used over scan lengths up to 270 mm. The Doppler signals are processed in the conventional manner using a frequency counter. The analog velocity output from the counter is post-processed to obtain the velocity profile. The Chebyshev demodulation post-processing technique for processing the velocity signals from solid surfaces has been introduced. The data processing technique directly yields the spatial velocity distribution in approximate functional form through frequency domain analysis of the scanning LDV velocity output. Results from a rotating disk setup are presented to illustrate the concept.

  9. Cow's milk allergy: color Doppler ultrasound findings in infants with hematochezia.

    PubMed

    Epifanio, Matias; Spolidoro, Jose Vicente; Missima, Nathalia Guarienti; Soder, Ricardo Bernardi; Garcia, Pedro Celiny Ramos; Baldisserotto, Matteo

    2013-01-01

    ultrasound (US) has been an important diagnostic tool to identify several causes of gastrointestinal bleeding. Infants with cow's milk allergy (CMA) may present hematochezia and the confirmation of the diagnosis can be difficult. The aim of this study is to describe grayscale and color Doppler ultrasound findings in patients with CMA. we retrospectively studied 13 infants with CMA. All infants presented severe hematochezia and abdominal pain. All underwent an US study with the diagnosis of allergic colitis. This diagnosis was based on clinical findings, recovery after infant or mother exclusion diets in the case of exclusive breastfeeding and positive oral challenge test. the mean age ranged from 1 to 6 months (mean=3.53). Seven out of 13 infants (53.8%) had grayscale and color Doppler sonographic repeated after exclusion diet. Twelve out of 13 (92,3%) showed abnormalities at US and CDUS at beginning. The positive findings suggesting colitis were thickened bowel walls and increased vascularity, especially in the descending and sigmoid colon. Colonoscopy and histopathological findings were compatible with allergic colitis. After a diet change the 13 infants recovered and their oral challenge tests were positive. Doppler US may be very useful in diagnosing secondary colitis, such as CMA, and to exclude several other abdominal diseases that can emulate this disease. Copyright © 2013 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  10. Transcranial power M-mode Doppler ultrasound for diagnosis of patent foramen ovale

    NASA Astrophysics Data System (ADS)

    Moehring, Mark; Spencer, Merrill

    2005-04-01

    Patent foramen ovale (PFO) is a right-to-left shunt (RLS) which communicates blood from the right to left atrium of the heart. PFO has been associated with stroke and, more recently, with migraine headache. Diagnosis of RLS can be accomplished effectively with transcranial power M-mode Doppler ultrasound (PMD). PMD is a modality which can be performed without the sedation required by the more invasive diagnostic technique using transesophageal echocardiography. PMD for this application consists of 2 MHz pulse Doppler ultrasound with placement of sample gates at 2 mm intervals along the single-transducer beam axis, and 8 kHz pulse repetition rate (PMD100M, Spencer Technologies). Doppler power versus depth is constructed every 4ms, using 33 sample gates. Bubble microemboli injected in the venous system and moving across a PFO present as high intensity tracks on a PMD image, as emboli transit from the heart to the brain and through the observed cerebral vasculature. Use of PMD in this context has been reported in the clinical literature [M. P. Spencer, M. A. Moehring, J. Jesurum et al, J. Neuroimaging 14, 342-349 (2004)]. This talk surveys the basic technical features of PMD for sensing PFO-related showers of bubble microemboli, and how these features provide clues to the severity of PFO.

  11. The removal of wall components in Doppler ultrasound signals by using the empirical mode decomposition algorithm.

    PubMed

    Zhang, Yufeng; Gao, Yali; Wang, Le; Chen, Jianhua; Shi, Xinling

    2007-09-01

    Doppler ultrasound systems, used for the noninvasive detection of the vascular diseases, normally employ a high-pass filter (HPF) to remove the large, low-frequency components from the vessel wall from the blood flow signal. Unfortunately, the filter also removes the low-frequency Doppler signals arising from slow-moving blood. In this paper, we propose to use a novel technique, called the empirical mode decomposition (EMD), to remove the wall components from the mixed signals. The EMD is firstly to decompose a signal into a finite and usually small number of individual components named intrinsic mode functions (IMFs). Then a strategy based on the ratios between two adjacent values of the wall-to-blood signal ratio (WBSR) has been developed to automatically identify and remove the relevant IMFs that contribute to the wall components. This method is applied to process the simulated and clinical Doppler ultrasound signals. Compared with the results based on the traditional high-pass filter, the new approach obtains improved performance for wall components removal from the mixed signals effectively and objectively, and provides us with more accurate low blood flow.

  12. Development of a control algorithm for the ultrasound scanning robot (NCCUSR) using ultrasound image and force feedback.

    PubMed

    Kim, Yeoun Jae; Seo, Jong Hyun; Kim, Hong Rae; Kim, Kwang Gi

    2017-06-01

    Clinicians who frequently perform ultrasound scanning procedures often suffer from musculoskeletal disorders, arthritis, and myalgias. To minimize their occurrence and to assist clinicians, ultrasound scanning robots have been developed worldwide. Although, to date, there is still no commercially available ultrasound scanning robot, many control methods have been suggested and researched. These control algorithms are either image based or force based. If the ultrasound scanning robot control algorithm was a combination of the two algorithms, it could benefit from the advantage of each one. However, there are no existing control methods for ultrasound scanning robots that combine force control and image analysis. Therefore, in this work, a control algorithm is developed for an ultrasound scanning robot using force feedback and ultrasound image analysis. A manipulator-type ultrasound scanning robot named 'NCCUSR' is developed and a control algorithm for this robot is suggested and verified. First, conventional hybrid position-force control is implemented for the robot and the hybrid position-force control algorithm is combined with ultrasound image analysis to fully control the robot. The control method is verified using a thyroid phantom. It was found that the proposed algorithm can be applied to control the ultrasound scanning robot and experimental outcomes suggest that the images acquired using the proposed control method can yield a rating score that is equivalent to images acquired directly by the clinicians. The proposed control method can be applied to control the ultrasound scanning robot. However, more work must be completed to verify the proposed control method in order to become clinically feasible. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Pathological prenatal Doppler sonography findings and their association with neonatal cranial ultrasound abnormalities in a high risk collective.

    PubMed

    Meyberg-Solomayer, G C; Soen, M; Speer, R; Poets, C; Goelz, R; Wallwiener, D; Solomayer, E-F

    2008-08-01

    The aim of this study was to evaluate whether prenatal Doppler ultrasound plays a role in the risk assessment of neonatal abnormal cranial ultrasound findings (NACU). Doppler examinations of blood flow velocities in the umbilical artery (n = 132), the fetal middle cerebral artery (n = 96) and the ductus venosus (n = 46) were conducted in 132 consecutive high-risk cases. The cases were divided into three groups: normal (I), pathological (II) and highly pathological Doppler (III) results, according to the resistance index calculated and were assessed for any association between the Doppler groups and the short-term outcome of the neonate, especially NACU. A significant association was found between Doppler groups and gestational age at delivery, birth weight, length and head circumference, growth restriction, cesarean section rate, Apgar score and pH values. NACU was diagnosed significantly more often in the pathological (12.1%) and highly pathological (38.5%) Doppler groups than in the group with normal Doppler (1.7%; p < 0.001). Multivariate analysis showed that the Doppler groups (odds ratio 1.67, 95% confidence interval [CI] 1.14-2.84, p < 0.001) and gestational age at delivery (odds ratio 1.37, 95% CI 1.08-2.74; p < 0.001) were independent variables that could be used to predict NACU. The present study showed that a pathological prenatal Doppler result is highly predictive for NACU in addition to gestational age and can therefore be used for risk assessment.

  14. Ultrasound assessed thickness of burn scars in association with laser Doppler imaging determined depth of burns in paediatric patients.

    PubMed

    Wang, Xue-Qing; Mill, Julie; Kravchuk, Olena; Kimble, Roy M

    2010-12-01

    This study describes the ultrasound assessment of burn scars in paediatric patients and the association of these scar thickness with laser Doppler imaging (LDI) determined burn depth. A total of 60 ultrasound scar assessments were conducted on 33 scars from 21 paediatric burn patients at 3, 6 and 9 months after-burn. The mean of peak scar thickness was 0.39±0.032 cm, with the thickest at 6 months (0.40±0.036 cm). There were 17 scald burn scars (0.34±0.045 cm), 4 contact burn scars (0.61±0.092 cm), and 10 flame burn scars (0.42±0.058 cm). Each group of scars followed normal distributions. Twenty-three scars had original burns successfully scanned by LDI and various depths of burns were presented by different colours according to blood perfusion units (PU), with dark blue <125, light blue 125-250, and green 250-440 PU. The thickness of these scars was significantly different between the predominant colours of burns, with the thinnest scars for green coloured burns and the thickest for dark blue coloured burns. Within light blue burns, grafted burns healed with significantly thinner scars than non-grafted burns. This study indicates that LDI can be used for predicting the risk of hypertrophic scarring and for guiding burn care. To our knowledge, this is the first study to correlate the thickness of burns scars by ultrasound scan with burn depth determined by LDI. Copyright © 2010 Elsevier Ltd and ISBI. All rights reserved.

  15. Application of high frequency color Doppler ultrasound in the monitoring of rheumatoid arthritis treatment

    PubMed Central

    ZHENG, GUIMIN; WANG, LEI; JIA, XIUCHUAN; LI, FANG; YAN, YONGLONG; YU, ZHIBO; LI, LI; WEI, QUN; ZHANG, FENGXIAO

    2014-01-01

    The aim of the present study was to explore the use of high frequency color Doppler ultrasound to measure synovial thickness and blood flow to assess the therapeutic value of the recombinant human tumor necrosis factor (TNF) II receptor antibody fusion protein in rheumatoid arthritis (RA) treatment. A total of 36 clinically-diagnosed patients with RA were treated with methotrexate tablets or the recombinant TNF-receptor antibody fusion protein for 24 weeks. Joint synovial thickness and synovial blood flow integrity were monitored by high frequency color Doppler in the second metacarpophalangeal joint in one hand. The correlation of the erythrocyte sedimentation rate, C-reactive protein (CRP) and 28-joint disease activity score (DAS28) with the ultrasound parameters were analyzed. Metacarpophalangeal second joint 2 (MCP2) synovial thickness, wrist joint synovial thickness and MCP2 synovial blood flow, prior and subsequent to the treatment, have a high correlation with DAS28 (P<0.05), and the MCP2 synovial blood flow integral has a strong correlation with CRP. Evaluating the wrist joint synovial thickness and synovial integrity of the second metacarpophalangeal joint using high frequency ultrasound detection can effectively evaluate the disease status in patients with RA. This procedure is potentially valuable as a means of evaluating the curative effects of RA treatments. PMID:25371736

  16. Assessment of Spectral Doppler in Preclinical Ultrasound Using a Small-Size Rotating Phantom

    PubMed Central

    Yang, Xin; Sun, Chao; Anderson, Tom; Moran, Carmel M.; Hadoke, Patrick W.F.; Gray, Gillian A.; Hoskins, Peter R.

    2013-01-01

    Preclinical ultrasound scanners are used to measure blood flow in small animals, but the potential errors in blood velocity measurements have not been quantified. This investigation rectifies this omission through the design and use of phantoms and evaluation of measurement errors for a preclinical ultrasound system (Vevo 770, Visualsonics, Toronto, ON, Canada). A ray model of geometric spectral broadening was used to predict velocity errors. A small-scale rotating phantom, made from tissue-mimicking material, was developed. True and Doppler-measured maximum velocities of the moving targets were compared over a range of angles from 10° to 80°. Results indicate that the maximum velocity was overestimated by up to 158% by spectral Doppler. There was good agreement (<10%) between theoretical velocity errors and measured errors for beam-target angles of 50°–80°. However, for angles of 10°–40°, the agreement was not as good (>50%). The phantom is capable of validating the performance of blood velocity measurement in preclinical ultrasound. PMID:23711503

  17. Sonographic imaging of extra-testicular focal lesions: comparison of grey-scale, colour Doppler and contrast-enhanced ultrasound

    PubMed Central

    Rafailidis, Vasileios; Robbie, Hasti; Konstantatou, Eleni; Huang, Dean Y; Deganello, Annamaria; Sellars, Maria E; Cantisani, Vito; Isidori, Andrea M

    2016-01-01

    Extra-testicular lesions are usually benign but present with nonspecific grey-scale sonography findings. This study assesses conventional sonographic characteristics in the differentiation of extra-testicular tumoural from inflammatory lesions and whether contrast-enhanced ultrasound has a role. A retrospective database analysis was performed. All patients were examined by experienced sonographers employing standard techniques combining grey-scale, colour Doppler sonography and contrast-enhanced ultrasound. Features recorded were: clinical symptoms, size, location, echogenicity, colour Doppler sonography and contrast-enhanced ultrasound enhancement. Vascularity on colour Doppler sonography and contrast-enhanced ultrasound was graded and compared. The lesions were classified as tumoural or inflammatory. The Chi-square test was used to analyse the sonographic patterns and kappa coefficient to measure the agreement between colour Doppler sonography and contrast-enhanced ultrasound. A total of 30 lesions were reviewed (median diameter 12 mm, range 5–80 mm, median age 52 years, range 18–86 years), including 13/30 tumoural and 17/30 inflammatory lesions. Lesions were hypoechoic (n = 12), isoechoic (n = 6), hyperechoic (n = 2) or mixed (n = 10). Grey-scale characteristics of tumoural vs. inflammatory lesions differed significantly (P = 0.026). On colour Doppler sonography, lesions had no vessels (n = 16), 2–3 vessels (n = 10) and ≥4 vessels (n = 4). On contrast-enhanced ultrasound, lesions showed no vascularity (n = 17), perfusion similar to testis (n = 7) and higher (n = 6). All abscesses identified (n = 9) showed no vascularity on both colour Doppler sonography and contrast-enhanced ultrasound. There was good agreement between these techniques in evaluating vascularity (κ = 0.719) and no significant difference between colour Doppler sonography and contrast-enhanced ultrasound of tumoural vs. inflammatory

  18. Design and Development of a Scanning Airborne Direct Detection Doppler Lidar System

    NASA Technical Reports Server (NTRS)

    Gentry, Bruce; McGill, Matthew; Schwemmer, Geary; Hardesty, Michael; Brewer, Alan; Wilkerson, Thomas; Atlas, Robert; Sirota, Marcos; Lindemann, Scott

    2006-01-01

    In the fall of 2005 we began developing an airborne scanning direct detection molecular Doppler lidar. The instrument is being built as part of the Tropospheric Wind Lidar Technology Experiment (TWiLiTE), a three year project selected by the NASA Earth Sun Technology Office under the Instrument Incubator Program. The TWiLiTE project is a collaboration involving scientists and engineers from NASA Goddard Space Flight Center, NOAA ESRL, Utah State University Space Dynamics Lab, Michigan Aerospace Corporation and Sigma Space Corporation. The TWiLiTE instrument will leverage significant research and development investments made by NASA Goddard and it's partners in the past several years in key lidar technologies and sub-systems (lasers, telescopes, scanning systems, detectors and receivers) required to enable spaceborne global wind lidar measurement. These sub-systems will be integrated into a complete molecular direct detection Doppler wind lidar system designed for autonomous operation on a high altitude aircraft, such as the NASA WB57. The WB57 flies at an altitude of 18 km and from this vantage point the nadir viewing Doppler lidar will be able to profile winds through the full troposphere. The TWiLiTE integrated airborne Doppler lidar instrument will be the first demonstration of a airborne scanning direct detection Doppler lidar and will serve as a critical milestone on the path to a future spaceborne tropospheric wind system. In addition to being a technology testbed for space based tropospheric wind lidar, when completed the TWiLiTE high altitude airborne lidar will be used for studying mesoscale dynamics and storm research (e.g. winter storms, hurricanes) and could be used for calibration and validation of satellite based wind systems such as ESA's Aeolus Atmospheric Dynamics Mission. The TWiLiTE Doppler lidar will have the capability to profile winds in clear air from the aircraft altitude of 18 km to the surface with 250 m vertical resolution and < 2mls

  19. Image analysis of placental issues using three-dimensional ultrasound and color power doppler

    NASA Astrophysics Data System (ADS)

    Wang, Qi; Cheng, Qiong; Liu, J. G.

    2007-12-01

    With the development of birthing-process medical science, and insurance requirement of prepotency, the ultrasound technique is widely used in the application of obstetrics realm, especially on the monitoring of embryo's growth. In the recent decade, the introduction of high resolution three-dimensional ultrasonic and color power Doppler scanner provides a much more direct, sensitive, forerunner method for the monitoring of embryo and gravida's prediction. A novel method that depends on examining images of vasculature of placenta to determine the growth of embryo is introduced in this paper. First, get a set of placenta vascularity images of the pregnant woman, taken by Color Doppler Ultrasonic Scanner, then mark some points in these images, where we get a section image, thus we can observe the internal blood vessel distribution at those points. This method provides an efficient tool for doctors.

  20. Three-dimensional ultrasound power Doppler assessment of the cervix: comparison between nulliparas and multiparas.

    PubMed

    Basgul, Alin; Kavak, Zehra Nese; Bakirci, Nadi; Gokaslan, Husnu

    2007-01-01

    To assess the sonographic cervical characteristics between nulliparous and multiparous women. Transvaginal three-dimensional ultrasound and power Doppler using the virtual organ computer-aided analysis (VOCAL) program were performed on 71 nulliparas and 59 multiparas at a mean gestational age of 25.3+/-7.9 weeks. We compared the cervical volume and power Doppler vascularization index (VI), flow index (FI), and vascularization-flow index (VFI) between nulliparas and multiparas. The mean cervical volume and mean VI, VFI, FI measurements were not significantly different between multiparas and nulliparas. Our observations suggest that the morphological changes in the cervix of parous women are merely configurational without a change in cervical mass and vascularization. These configurational changes might result from the inevitable cervical stretching during labor and represent a healing process that does not involve a subsequent change in mass or vascularity.

  1. Exploiting continuous scanning laser Doppler vibrometry (CSLDV) in time domain correlation methods for noise source identification

    NASA Astrophysics Data System (ADS)

    Chiariotti, Paolo; Martarelli, Milena; Revel, Gian Marco

    2014-07-01

    This paper proposes the use of continuous scanning laser Doppler vibrometry (CSLDV) in time domain correlation techniques that aim at characterizing the structure-borne contributions of the noise emission of a mechanical system. The time domain correlation technique presented in this paper is based on the use of FIR (finite impulse response) filters obtained from the vibro-acoustic transfer matrix when vibration data are collected by laser Doppler vibrometry (LDV) exploited in continuous scan mode (CSLDV). The advantages, especially in terms of source decorrelation capabilities, related to the use of CSLDV for such purpose, with respect to standard discrete scan (SLDV), are discussed throughout the paper. To validate this approach, vibro-acoustic measurements were performed on a planetary gear motor for home appliances. The analysis of results is also supported by a simulation.

  2. Limited Accuracy of Colour Doppler Ultrasound Dynamic Tissue Perfusion Measurement in Diabetic Adults

    PubMed Central

    Stoperka, Felix; Karger, Claudia

    2016-01-01

    Dynamic tissue perfusion measurement (DTPM) is a pre-described and available method in pediatric ultrasound to quantify tissue perfusion in renal Doppler ultrasound by particular video analysis software. This study evaluates DTPM during single and between repeated visits after 6 months, calibrates repeated DTPM within different region of interest (ROI) and compares DTPM with kidney function markers in adult patients with early diabetic nephropathy (n = 17). During repeated measurements, no association of readings at the same patients in the same (n = 3 readings) as well as repeated visit (n = 2 visits) could be retrieved. No association between DTPM, MDRD-GFR, albuminuria, age and duration of diabetes was observed. These negative results are presumably related to inconsistency of DTPM due to non-fixed ROI position as could be shown in calibrating series. Further development of the method should be performed to enable reproducible DTPM readings in adults. PMID:28033403

  3. A web-based interactive database system for a transcranial Doppler ultrasound laboratory.

    PubMed

    Gorman, Mark J; Jacobs, Bradley; Sloan, Michael; Roth, Yuval; Levine, Steven R

    2006-01-01

    Variations in transcranial Doppler (TCD) examination performance techniques and interpretive paradigms between individual laboratories are a common challenge in the practice of TCD. Demand for rapid access to patient ultrasound examination data and report for use in intensive care settings has necessitated a more flexible approach to data management. Both of these issues may benefit from a computerized approach. We describe the application of a World Wide Web-based database system for use in an ultrasound laboratory. Results. Databasing information while generating a TCD report is efficient. Web accessibility allows rapid and flexible communication of time-sensitive report information and interpretation for more expeditious clinical decision making. Web-based applications can extend the reach and efficiency of traditionally structured medical laboratories.

  4. Wrist ultrasound examination – scanning technique and ultrasound anatomy. Part 1: Dorsal wrist

    PubMed Central

    Łasecki, Mateusz; Zaleska-Dorobisz, Urszula

    2015-01-01

    Ultrasound imaging of the musculoskeletal system is superior to other imaging methods in many aspects, such as multidimensional character of imaging, possibility of dynamic evaluation and precise assessment of soft tissues. Moreover, it is a safe and relatively inexpensive method, broadly available and well-tolerated by patients. A correctly conducted ultrasound examination of the wrist delivers detailed information concerning the condition of tendons, muscles, ligaments, nerves and vessels. However, the knowledge of anatomy is crucial to establish a correct ultrasound diagnosis, also in wrist assessment. An ultrasound examination of the wrist is one of the most common US examinations conducted in patients with rheumatological diseases. Ultrasonographic signs depend on the advancement of the disease. The examination is equally frequently conducted in patients with pain or swelling of the wrist due to non-rheumatological causes. The aim of this publication was to present ultrasound images and anatomic schemes corresponding to them. The correct scanning technique of the dorsal part of the wrist was discussed and some practical tips, thanks to which highly diagnostic images can be obtained, were presented. The following anatomical structures should be visualized in an ultrasound examination of the dorsal wrist: distal radio-ulnar joint, radiocarpal joint, midcarpal joint, carpometacarpal joints, dorsal radiocarpal ligament, compartments of extensor tendons, radial artery, cephalic vein, two small branches of the radial nerve: superficial and deep, as well as certain midcarpal ligaments, particularly the scapholunate ligament and lunotriquetral ligament. The paper was distinguished in 2014 as the “poster of the month” (poster number C-1896) during the poster session of the European Congress of Radiology in Vienna. PMID:26675810

  5. The ultrasound brain helmet: early human feasibility study of multiple simultaneous 3D scans of cerebral vasculature

    NASA Astrophysics Data System (ADS)

    Lindsey, Brooks D.; Ivancevich, Nikolas M.; Whitman, John; Light, Edward; Fronheiser, Matthew; Nicoletto, Heather A.; Laskowitz, Daniel T.; Smith, Stephen W.

    2009-02-01

    We describe early stage experiments to test the feasibility of an ultrasound brain helmet to produce multiple simultaneous real-time 3D scans of the cerebral vasculature from temporal and suboccipital acoustic windows of the skull. The transducer hardware and software of the Volumetrics Medical Imaging real-time 3D scanner were modified to support dual 2.5 MHz matrix arrays of 256 transmit elements and 128 receive elements which produce two simultaneous 64° pyramidal scans. The real-time display format consists of two coronal B-mode images merged into a 128° sector, two simultaneous parasagittal images merged into a 128° × 64° C-mode plane, and a simultaneous 64° axial image. Real-time 3D color Doppler images acquired in initial clinical studies after contrast injection demonstrate flow in several representative blood vessels. An offline Doppler rendering of data from two transducers simultaneously scanning via the temporal windows provides an early visualization of the flow in vessels on both sides of the brain. The long-term goal is to produce real-time 3D ultrasound images of the cerebral vasculature from a portable unit capable of internet transmission, thus enabling interactive 3D imaging, remote diagnosis and earlier therapeutic intervention. We are motivated by the urgency for rapid diagnosis of stroke due to the short time window of effective therapeutic intervention.

  6. Time-resolved measurement of bubble cavitation by using power Doppler ultrasound image

    NASA Astrophysics Data System (ADS)

    Koda, Ren; Izumi, Yosuke; Nagai, Hayato; Yamakoshi, Yoshiki

    2017-04-01

    In this study, a novel measurement method for a secondary ultrasound wave irradiated by microbubble cavitation is proposed. High-intensity ultrasound (h-US, 1.0-1.5 MPa), which produces bubble cavitation, is irradiated with a fixed time delay after introducing imaging US, whose frequency is different from that of the h-US. The bubble cavitation signal (BCS) is detected by the signal-processing unit of an ultrasound power Doppler imaging instrument. By this method, both a spatially resolved bubble image (S-image) and the temporal transition of the BCS (T-image) are monitored simultaneously. A feature of the method is that the BCS is observed in situ with sub-µs time resolution. The accuracy of the method is evaluated and it is found that the maximum deviation of the amplitude of the simulated BCS is 4.80%. This method is applied to measure the BCS of ultrasound contrast agent microbubbles. As a result, the dependence of the inherent temporal transition of the BCS on the sound pressure of the h-US (0.6-1.2 MPa) is observed.

  7. Early diagnosis and outcome prediction of neonatal hypoxic-ischemic encephalopathy with color Doppler ultrasound.

    PubMed

    Guan, B; Dai, C; Zhang, Y; Zhu, L; He, X; Wang, N; Liu, H

    2017-06-01

    To describe the ultrasound presentation of the brain and cerebral hemodynamics in neonates with hypoxic-ischemic encephalopathy (HIE) by comparison with control subjects. During June 2012 to April 2013, full term neonates who had clinical evidence of HIE were enrolled. Healthy newborns without HIE were used as a control group. Cerebral parenchyma, size of lateral ventricles and hemodynamic parameters of cerebral arteries were studied using two-dimensional duplex and color Doppler ultrasound. Neonates with moderate and severe HIE were followed-up with ultrasound for at least 3 months. A total of 158 consecutive neonates (82 boys and 76 girls), including 54 with mild HIE, 60 with moderate HIE and 44 with severe HIE were included. One hundred and twenty healthy newborns were randomly selected as a control group. Abnormal ultrasound findings of brain parenchyma were found in 25/54 (46.3%) neonates with mild HIE whereas they were found in 58/60 (96.7%) neonates with moderate HIE and 44/44 (100%) neonates with severe HIE. Almost all neonates with severe HIE had decreased cerebral artery blood flow velocity and increased resistance index of cerebral arteries. Of the 104 neonates with moderate or severe HIE, follow-up ultrasound examination revealed cystic parenchymal lesions in 12/104 (11.5%), progressive ventricular dilatation and brain atrophy in 12/104 (11.5%), mild ventricular dilatation in 15/104 (14.4%) and leukoencephalomalacia in 2/104 (1.9%) neonates. Ultrasound features such as the size of lateral ventricles, altered brain parenchymal echogenicity and cerebral blood flow parameters are useful for the early diagnosis of HIE and help predict outcome. Copyright © 2016 Editions françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved.

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

    PubMed

    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.

  9. Expected Characteristics of Global Wind Profile Measurements with a Scanning, Hybrid, Doppler Lidar System

    NASA Technical Reports Server (NTRS)

    Kavaya, Michael J.

    2008-01-01

    Over 20 years of investigation by NASA and NOAA scientists and Doppler lidar technologists into a global wind profiling mission from earth orbit have led to the current favored concept of an instrument with both coherent- and direct-detection pulsed Doppler lidars (i.e., a hybrid Doppler lidar) and a stepstare beam scanning approach covering several azimuth angles with a fixed nadir angle. The nominal lidar wavelengths are 2 microns for coherent detection, and 0.355 microns for direct detection. The two agencies have also generated two sets of sophisticated wind measurement requirements for a space mission: science demonstration requirements and operational requirements. The requirements contain the necessary details to permit mission design and optimization by lidar technologists. Simulations have been developed that connect the science requirements to the wind measurement requirements, and that connect the wind measurement requirements to the Doppler lidar parameters. The simulations also permit trade studies within the multi-parameter space. These tools, combined with knowledge of the state of the Doppler lidar technology, have been used to conduct space instrument and mission design activities to validate the feasibility of the chosen mission and lidar parameters. Recently, the NRC Earth Science Decadal Survey recommended the wind mission to NASA as one of 15 recommended missions. A full description of the wind measurement product from these notional missions and the possible trades available are presented in this paper.

  10. Remote measurement utilizing NASA's scanning laser Doppler systems. Volume 1. Laser Doppler wake vortex tracking at Kennedy Airport

    NASA Technical Reports Server (NTRS)

    Krause, M. C.; Wilson, D. J.; Howle, R. E.; Edwards, B. B.; Craven, C. E.; Jetton, J. L.

    1976-01-01

    Test operations of the Scanning Laser Doppler System (SLDS) at Kennedy International Airport (KIA) during August 1974 through June 1975 are reported. A total of 1,619 data runs was recorded with a totally operational system during normal landing operations at KIA. In addition, 53 data runs were made during cooperative flybys with the C880 for a grand total of 1672 recorded vortex tracks. Test crews were in attendance at KIA for 31 weeks, of which 25 weeks were considered operational and the other six were packing, unpacking, setup and check out. Although average activity equates to 67 recorded landing operations per week, two periods of complete runway inactivity spanned 20 days and 13 days, respectively. The operation frequency therefore averaged about 88 operations per week.

  11. New adaptive clutter rejection for ultrasound color Doppler imaging: in vivo study.

    PubMed

    Yoo, Yang Mo; Kim, Yongmin

    2010-03-01

    Clutter rejection is essential for accurate flow estimation in ultrasound color Doppler imaging. In this article, we present a new adaptive clutter rejection (ACR) technique where an optimum filter is dynamically selected depending upon the underlying clutter characteristics (e.g., tissue acceleration and power). We compared the performance of the ACR method with other adaptive methods, i.e., down-mixing (DM) and adaptive clutter filtering (ACF), using in vivo data acquired from the kidney, liver and common carotid artery. With the kidney data, the ACR method provided an average improvement of 3.05 dB and 1.7 dB in flow signal-to-clutter ratio (SCR) compared with DM and ACF, respectively. With the liver data, SCR was improved by 2.75 dB and 1.8 dB over DM and ACF while no significant improvement with ACR was found in the common carotid artery data. Thus, the proposed adaptive method could provide more accurate flow estimation by improving clutter rejection in abdominal ultrasound color Doppler imaging pending validation.

  12. Real-time numerical simulation of Doppler ultrasound in the presence of nonaxial flow.

    PubMed

    Khoshniat, Mahdieh; Thorne, Meghan L; Poepping, Tamie L; Hirji, Samira; Holdsworth, David W; Steinman, David A

    2005-04-01

    Numerical simulations of Doppler ultrasound (DUS) relying on computational fluid dynamics (CFD) models of nonaxial flow have traditionally employed detailed (but computationally intensive) models of the DUS physics, or have sacrificed much of the physics in the interest of computational or conceptual simplicity. In this paper, we present a compromise between these extremes, with the objective of simulating the essential characteristics of DUS spectrograms in a real-time manner. Specifically, a precomputed pulsatile CFD velocity field is interrogated at some number, N, of discrete points distributed spatially within a sample volume of prescribed geometry and power distribution and temporally within a prescribed sampling window. Intrinsic spectral broadening is accounted for by convolving each of the point velocities with a semiempirical broadening function. Real-time performance is facilitated through the use of an efficient algorithm for interpolating the unstructured CFD data. A spherical sample volume with Gaussian power distribution, N = 1000 sampling points, and quadratic broadening function are shown to be adequate for simulating, at frame rates of 86 Hz on a 1.5 GHz desktop workstation, realistic-looking spectrograms at representative locations within a stenosed carotid bifurcation model. Via qualitative comparisons with matched in vitro data, these simulated spectrograms are shown to mimic the distinctive spectral envelopes, broadening and power characteristics associated with common carotid, stenotic jet and poststenotic recirculating flows. We conclude that the complex interaction between Doppler ultrasound and complicated clinically relevant blood flow dynamics can be simulated in real time via this relatively straightforward semiempirical approach.

  13. Renal transplantation parenchymal complications: what Doppler ultrasound can and cannot do.

    PubMed

    Granata, Antonio; Di Nicolò, Pierpaolo; Scarfia, Viviana R; Insalaco, Monica; Lentini, Paolo; Veroux, Massimiliano; Fatuzzo, Pasquale; Fiorini, Fulvio

    2015-06-01

    Kidney transplantation is the treatment of choice in end-stage renal disease, given the better quality of life of transplanted patients when compared with patients on maintenance dialysis. In spite of surgical improvements and new immunosuppressive regimens, parts of transplanted grafts still develop chronic dysfunction. Ultrasonography, both in B-mode and with Doppler ultrasound, is an important diagnostic tool in case of clinical conditions which might impair kidney function. Even though ultrasonography is considered fundamental in the diagnosis of vascular and surgical complications of the transplanted kidney, its role is not fully understood in case of parenchymal complications of the graft. The specificity of Doppler is low both in case of acute complications, such as acute tubular necrosis, drugs toxicity and acute rejection, and in case of chronic conditions, such as chronic allograft nephropathy. Single determinations of resistance indices present low diagnostic accuracy, which is higher in case of successive measurements performed during the follow-up of the graft. Modern techniques such as tissue pulsatility index, maximal fractional area and contrast-enhanced ultrasound increase ultrasonography diagnostic power in case of parenchymal complications of the transplanted kidney.

  14. Neovascularity in patellar tendinopathy and the response to eccentric training: a case report using Power Doppler ultrasound.

    PubMed

    McCreesh, Karen M; Riley, Sara J; Crotty, James M

    2013-12-01

    This report describes the case of an amateur soccer player with chronic patellar tendinopathy who underwent ultrasound imaging before and after engaging in an 8-week programme of eccentric exercise. On initial assessment, greyscale ultrasound imaging demonstrated tendon thickening and reduced echogenicity, while Power Doppler imaging demonstrated a large amount of neovascularity. After 8 weeks of an eccentric loading programme, the patient reported significantly improved symptoms and functional scores, while follow-up imaging demonstrated improvement in the echo appearance of the tendon and complete resolution of the neovascularity. The association between neovascularity and symptoms in tendinopathy research is conflicting, with a paucity of research in the area of patellar tendinopathy. While further research is needed to clarify the significance of greyscale and Power Doppler ultrasound changes in relation to symptoms in patellar tendinopathy, ultrasound imaging was shown to be a useful adjunct to diagnosis and outcome assessment in this case.

  15. Microscopic observation of glass bead movement in soft tissue-mimicking phantom under ultrasound PW mode scanning.

    PubMed

    Liu, Lei; Funamoto, Kenichi; Tanabe, Masayuki; Hayase, Toshiyuki

    2015-01-01

    Previous studies have demonstrated that stones and calcification in soft tissue show special enhancement in response to color flow (CF) or pulse Doppler (PW) mode ultrasound scan. This phenomenon is known as the "twinkling sign (TS)". The authors conducted an in vitro experiment to investigate the mechanism of TS occurrence by observing a glass bead in a transparent PVA-H soft tissue-mimicking phantom. The TS in PW mode showed a low-power and slow-velocity spectrum. At the same time, analysis of images by high-speed camera showed that the glass bead in the phantom oscillated following the pulse repetition frequency (PRF) of the PW mode ultrasound scan. The harmonic oscillations were confirmed, as well. The ultrasound radiation force-driven micro-oscillation possibly affects the ultrasound propagation around the scatterer and triggers random signals in the received echo signals. The results indicate that TS is a phenomenon based on complicated acoustic-mechanical interaction of multiple mechanisms. Further investigation is required for gaining a full understanding of the mechanism of TS occurrence and its clinical application.

  16. Nonmechanical scanning laser Doppler velocimeter for cross-sectional two-dimensional velocity measurement.

    PubMed

    Maru, Koichi; Hata, Takahiro

    2012-12-01

    We propose a two-dimensional scanning laser Doppler velocimeter (LDV) that does not require any moving mechanisms in its probe. In the proposed LDV, the measurement position can be scanned in two dimensions on a cross-sectional plane perpendicular to the direction of flow. The combination of the change in wavelength and change in port of the fiber array input to the probe is utilized for the scan. The experimental results using a sensor probe setup indicate that the measurement position can be scanned in two dimensions using the proposed method. The scanning range was estimated to be 39.7 mm in the axial direction over the wavelength range of 1536-1554 nm and 26.1 mm in the transverse direction for the use of 22 ports of the fiber array.

  17. Development of a Mechanical Scanning-type Intravascular Ultrasound System Using a Miniature Ultrasound Motor

    NASA Astrophysics Data System (ADS)

    Tanabe, Masayuki; Xie, Shangping; Tagawa, Norio; Moriya, Tadashi; Furukawa, Yuji

    2007-07-01

    Intravascular ultrasound (IVUS) plays an important role for the detection of arteriosclerosis, which causes the ischemic heart disease. In mechanical scanning-type IVUS, it is necessary to rotate a transducer or a reflecting mirror. A method that involves rotating the transducer using a torque wire causes image distortion (NURD: non uniform rotation distortion). For a method that involves placing an electromagnetic motor on the tip of an IVUS probe is difficult to miniaturize the probe. Our objectives are to miniaturize the probe (1 mm in diameter, 5 mm in length) and to remove NURD. Therefore, we conducted a study to assess the feasibility of attaining these objectives by constructing a prototype IVUS system, in which an ultrasound motor using a stator in the form of a helical coil (abbreviated as CS-USM: coiled stator-ultrasonic motor) is incorporated, and to clarify problems that need to be solved in constructing the probe.

  18. Diagnostic efficacy of color Doppler ultrasound in evaluation of cervical lymphadenopathy.

    PubMed

    Misra, Deepankar; Panjwani, Sapna; Rai, Shalu; Misra, Akansha; Prabhat, Mukul; Gupta, Prashant; Talukder, Subrata K

    2016-01-01

    To evaluate the efficacy of color Doppler ultrasound (CDUS) in differentiating benign and malignant cervical lymph nodes by detecting differences in blood flow patterns. In this cross-sectional prospective study, 25 untreated patients with clinical evidence of cervical lymphadenopathy were evaluated. CDUS was performed for 80 cervical lymph nodes. The gray scale parameters of the lymph node and intranodal perfusion sites were the key CDUS features used to differentiate between reactive and metastatic lymph nodes. Histopathological confirmations were obtained and compared with the results of CDUS. Initially, 53 cervical lymph nodes were evaluated by clinical examination. Twenty-seven additional lymph nodes (53 + 27 = 80) were discovered by CDUS evaluation. Gray scale parameters for lymph nodes such as size of lymph node, shape of lymph node, and presence or absence of hilum revealed highly significant results (P < 0.0001). Color Doppler flow signals revealed that central/hilar flow was characteristic for benign nodes whereas peripheral/mixed flow was characteristic for malignant nodes, the findings were highly significant (P < 0.0001). Gray scale and color Doppler features are used to differentiate benign and malignant nodes. Within the limitations of this study, CDUS evaluation was found to be highly significant with a high sensitivity and specificity over clinical evaluation CDUS examination provides a prospect to reduce the need for biopsy/fine needle aspiration cytology in reactive nodes.

  19. Three-Dimensional Rapidly Scanning Laser Doppler Velocimeter with Low SNR Signal Processing

    DTIC Science & Technology

    1990-11-30

    Three-Dimensional Rapidly Scanning Laser Doppler Velocimeter with Low SNR Signal Processing 12. PERSONAL AUTHOR(S) Kevin A. Shinpaugh and Rog er L...curvature for concave mirror or lens surface s .................... object distance from lens s.. ................. image distance from lens SNR ...where the signal-to-noise ratio ( SNR ) of the PMT signal is 20 dB and signal processing is performed via the fast Fourier trasnform (FFT) with zero

  20. Developments in target micro-Doppler signatures analysis: radar imaging, ultrasound and through-the-wall radar

    NASA Astrophysics Data System (ADS)

    Clemente, Carmine; Balleri, Alessio; Woodbridge, Karl; Soraghan, John J.

    2013-12-01

    Target motions, other than the main bulk translation of the target, induce Doppler modulations around the main Doppler shift that form what is commonly called a target micro-Doppler signature. Radar micro-Doppler signatures are generally both target and action specific and hence can be used to classify and recognise targets as well as to identify possible threats. In recent years, research into the use of micro-Doppler signatures for target classification to address many defence and security challenges has been of increasing interest. In this article, we present a review of the work published in the last 10 years on emerging applications of radar target analysis using micro-Doppler signatures. Specifically we review micro-Doppler target signatures in bistatic SAR and ISAR, through-the-wall radar and ultrasound radar. This article has been compiled to provide radar practitioners with a unique reference source covering the latest developments in micro-Doppler analysis, extraction and mitigation techniques. The article shows that this research area is highly active and fast moving and demonstrates that micro-Doppler techniques can provide important solutions to many radar target classification challenges.

  1. [Ultrasound and color Doppler imaging for kidney and urinary tract tumors].

    PubMed

    Meola, Mario; Petrucci, Ilaria; Giovannini, Lisa; Colombini, Elisa; Villa, Adriana

    2012-01-01

    When a renal mass is suspected, conventional ultrasound and color Doppler imaging are often used for initial assessment. Ultrasound screening has many advantages over contrast-enhanced CT and MRI, such as accessibility, low costs, and no need for intravenous iodine contrast administration or ionizing radiation. Sonography is very helpful to distinguish cystic from solid lesions and to monitor the growth and structural pattern of cysts. Detection of small renal carcinoma of less than 3 cm in diameter is limited, however, and small tumors are detected by conventional ultrasound only in 67-79% of cases. In fact, small renal malignancies may have an echogenicity similar to the normal renal parenchyma. In these cases it is very hard to distinguish the tumor, particularly when there is no evident disarrangement of the normal renal contours and no extension into the central renal complex. Renal cell carcinoma can also be hypo- or hyperechoic and indistinguishable from renal adenoma/oncocytoma or angiomyolipomas, which are commonly described as hyperechoic masses. In other words, the pattern and ultrasound characteristics of renal masses often overlap between benign and malignant tumors. A diagnosis of a malignant cystic lesion requires evidence of multiple, thickened internal septa, calcifications, vascularity, and parietal nodularity. When a solid lesion does not show the typical appearance of a simple cyst (a round anechoic lesion with a smooth well-defined wall, without internal debris, and showing increased through-transmission), further evaluation with contrast-enhanced CT or MRI is necessary. Contrast-enhanced ultrasound (CEUS) improves the sensitivity for detection of small renal masses. Compared to CT, CEUS is able to better visualize the number of septa, the septum and wall thickness, the presence of a solid component, and enhancement in some cases, resulting in upgrading of the Bosniak classification and affecting treatment planning.

  2. Hurricane Wind Field Measurements with Scanning Airborne Doppler Lidar During CAMEX-3

    NASA Technical Reports Server (NTRS)

    Rothermel, Jeffry; Cutten, D. R.; Howell, J. N.; Darby, L. S.; Hardesty, R. M.; Traff, D. M.; Menzies, R. T.

    2000-01-01

    During the 1998 Convection and Moisture Experiment (CAMEX-3), the first hurricane wind field measurements with Doppler lidar were achieved. Wind fields were mapped within the eye, along the eyewall, in the central dense overcast, and in the marine boundary layer encompassing the inflow region. Spatial coverage was determined primarily by cloud distribution and opacity. Within optically-thin cirrus slant range of 20- 25 km was achieved, whereas no propagation was obtained during penetration of dense cloud. Measurements were obtained with the Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS) on the NASA DC-8 research aircraft. MACAWS was developed and operated cooperatively by the atmospheric lidar remote sensing groups of NOAA Environmental Technology Laboratory, NASA Marshall Space Flight Center, and Jet Propulsion Laboratory. A pseudo-dual Doppler technique ("co-planar scanning") is used to map the horizontal component of the wind at several vertical levels. Pulses from the laser are directed out the left side of the aircraft in the desired directions using computer-controlled rotating prisms. Upon exiting the aircraft, the beam is completely eyesafe. Aircraft attitude and speed are taken into account during real-time signal processing, resulting in determination of the ground-relative wind to an accuracy of about 1 m/s magnitude and about 10 deg direction. Beam pointing angle errors are about 0.1 deg, equivalent to about 17 m at 10 km. Horizontal resolution is about 1 km (along-track) for typical signal processor and scanner settings; vertical resolution varies with range. Results from CAMEX-3 suggest that scanning Doppler wind lidar can complement airborne Doppler radar by providing wind field measurements in regions that are devoid of hydrometeors. At present MACAWS observations are being assimilated into experimental forecast models and satellite Doppler wind lidar simulations to evaluate the relative impact.

  3. Hurricane Wind Field Measurements with Scanning Airborne Doppler Lidar During CAMEX-3

    NASA Technical Reports Server (NTRS)

    Rothermel, Jeffry; Cutten, D. R.; Howell, J. N.; Darby, L. S.; Hardesty, R. M.; Traff, D. M.; Menzies, R. T.

    2000-01-01

    During the 1998 Convection and Moisture Experiment (CAMEX-3), the first hurricane wind field measurements with Doppler lidar were achieved. Wind fields were mapped within the eye, along the eyewall, in the central dense overcast, and in the marine boundary layer encompassing the inflow region. Spatial coverage was determined primarily by cloud distribution and opacity. Within optically-thin cirrus slant range of 20- 25 km was achieved, whereas no propagation was obtained during penetration of dense cloud. Measurements were obtained with the Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS) on the NASA DC-8 research aircraft. MACAWS was developed and operated cooperatively by the atmospheric lidar remote sensing groups of NOAA Environmental Technology Laboratory, NASA Marshall Space Flight Center, and Jet Propulsion Laboratory. A pseudo-dual Doppler technique ("co-planar scanning") is used to map the horizontal component of the wind at several vertical levels. Pulses from the laser are directed out the left side of the aircraft in the desired directions using computer-controlled rotating prisms. Upon exiting the aircraft, the beam is completely eyesafe. Aircraft attitude and speed are taken into account during real-time signal processing, resulting in determination of the ground-relative wind to an accuracy of about 1 m/s magnitude and about 10 deg direction. Beam pointing angle errors are about 0.1 deg, equivalent to about 17 m at 10 km. Horizontal resolution is about 1 km (along-track) for typical signal processor and scanner settings; vertical resolution varies with range. Results from CAMEX-3 suggest that scanning Doppler wind lidar can complement airborne Doppler radar by providing wind field measurements in regions that are devoid of hydrometeors. At present MACAWS observations are being assimilated into experimental forecast models and satellite Doppler wind lidar simulations to evaluate the relative impact.

  4. The remote measurement of tornado-like flows employing a scanning laser Doppler system

    NASA Technical Reports Server (NTRS)

    Jeffreys, H. B.; Bilbro, J. W.; Dimarzio, C.; Sonnenschein, C.; Toomey, D.

    1977-01-01

    The paper deals with a scanning laser Doppler velocimeter system employed in a test program for measuring naturally occurring tornado-like phenomena, known as dust devils. A description of the system and the test program is followed by a discussion of the data processing techniques and data analysis. The system uses a stable 15-W CO2 laser with the beam expanded and focused by a 12-inch telescope. Range resolution is obtained by focusing the optical system. The velocity of each volume of air (scanned in a horizontal plane) is determined from spectral analysis of the heterodyne signal. Results derived from the measurement program and data/system analyses are examined.

  5. The remote measurement of tornado-like flows employing a scanning laser Doppler system

    NASA Technical Reports Server (NTRS)

    Jeffreys, H. B.; Bilbro, J. W.; Dimarzio, C.; Sonnenschein, C.; Toomey, D.

    1977-01-01

    The paper deals with a scanning laser Doppler velocimeter system employed in a test program for measuring naturally occurring tornado-like phenomena, known as dust devils. A description of the system and the test program is followed by a discussion of the data processing techniques and data analysis. The system uses a stable 15-W CO2 laser with the beam expanded and focused by a 12-inch telescope. Range resolution is obtained by focusing the optical system. The velocity of each volume of air (scanned in a horizontal plane) is determined from spectral analysis of the heterodyne signal. Results derived from the measurement program and data/system analyses are examined.

  6. Ultrasound safety in early pregnancy: reduced energy setting does not compromise obstetric Doppler measurements.

    PubMed

    Sande, R K; Matre, K; Eide, G E; Kiserud, T

    2012-04-01

    We hypothesized that first-trimester Doppler ultrasonography can be carried out at lower output energies than the currently advocated limits without compromising clinically important information. We recruited 42 pregnant women for an ultrasound examination at 12 weeks' gestation. Twenty-one women were examined with a transvaginal transducer, the rest with a transabdominal transducer. We used pulsed Doppler to measure pulsatility index (PI) and peak systolic velocity (PSV) in five clinically relevant fetal and maternal blood vessels. The energy indicator thermal index for bone (TIb) was set at 1.0, 0.5 and 0.1. Each measurement was repeated three times. A mixed linear regression model accounting for correlation between measurements was used to assess the effect of different TIb levels and transducers. We were able to visualize the vessels by color Doppler and measure PI and PSV in all vessels at all energy levels in all the participants with the exception of the ductus venosus in two participants, yielding 1872 recordings for statistical analysis. A reduction in TIb from 1.0 to 0.5 and 0.1 had no effect on the PI or PSV values, nor was there any trend towards higher parameter variance with decreasing TIb. There was no difference between measured values of PI and PSV between the transducers, but the transabdominal technique was associated with a greater parameter variance. Reliable first-trimester Doppler data can be obtained with output energy reduced to a TIb of 0.5 or 0.1. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.

  7. Color Doppler Ultrasound Velocimetry Flow Reconstruction using Vorticity-Streamfunction Formulation

    NASA Astrophysics Data System (ADS)

    Meyers, Brett; Vlachos, Pavlos; Goergen, Craig; Scalo, Carlo

    2016-11-01

    Clinicians commonly utilize Color Doppler imaging to qualitatively assess the velocity in patient cardiac or arterial flows. However Color Doppler velocity are restricted to two-dimensional one-component measurements. Recently new methods have been proposed to reconstruct a two-component velocity field from such data. Vector Flow Mapping (VFM), in particular, utilizes the conservation of mass to reconstruct the flow. However, this method over-simplifies the influence of wall and surrounding blood motion on local measurements, which produce large, non-physical velocity gradients, requiring excessive smoothing operations to remove. We propose a new approach based on the Vorticity-Stream Function (Ψ- ω) formulation that yields more physiologically accurate velocity gradients and avoids any added smoothing operations. Zero-penetration conditions are specified at the walls, removing the need for measurement of wall velocity from additional scans, which introduce further uncertainties in the reconstruction. Inflow and outflow boundary conditions are incorporated by prescribing Dirichlet boundary conditions. The proposed solver is compared against the VFM using computational data to evaluate measurement improvement. Finally we demonstrate the method by evaluating murine left ventricle Color Doppler scans.

  8. Evaluation of the Wind Flow Variability Using Scanning Doppler Lidar Measurements

    NASA Astrophysics Data System (ADS)

    Sand, S. C.; Pichugina, Y. L.; Brewer, A.

    2016-12-01

    Better understanding of the wind flow variability at the heights of the modern turbines is essential to accurately assess of generated wind power and efficient turbine operations. Nowadays the wind energy industry often utilizes scanning Doppler lidar to measure wind-speed profiles at high spatial and temporal resolution.The study presents wind flow features captured by scanning Doppler lidars during the second Wind Forecast and Improvement Project (WFIP 2) sponsored by the Department of Energy (DOE) and National Oceanic and Atmospheric Administration (NOAA). This 18-month long experiment in the Columbia River Basin aims to improve model wind forecasts complicated by mountain terrain, coastal effects, and numerous wind farms.To provide a comprehensive dataset to use for characterizing and predicting meteorological phenomena important to Wind Energy, NOAA deployed scanning, pulsed Doppler lidars to two sites in Oregon, one at Wasco, located upstream of all wind farms relative to the predominant westerly flow in the region, and one at Arlington, located in the middle of several wind farms.In this presentation we will describe lidar scanning patterns capable of providing data in conical, or vertical-slice modes. These individual scans were processed to obtain 15-min averaged profiles of wind speed and direction in real time. Visualization of these profiles as time-height cross sections allows us to analyze variability of these parameters with height, time and location, and reveal periods of rapid changes (ramp events). Examples of wind flow variability between two sites of lidar measurements along with examples of reduced wind velocity downwind of operating turbines (wakes) will be presented.

  9. [Standardised ultrasound scanning of the shoulder--normal and basic pathological findings].

    PubMed

    Laktasić-Zerjavić, Nadica; Perić, Porin

    2010-01-01

    Diagnostic ultrasound (US) is noninvasive, non-ionisating and cost-effective imaging diagnostic technique. It has emerged as a useful imaging modality for the diagnosis of joint and soft tissue pathology. The shoulder is probably the most frequently analyzed joint. Diagnostic US can be considered as an extension of physical examination and has better sensitivity and specificity for the detection of rotator cuff tendon tear compared to the physical examination. A high frequency linear probe (7.5-15 MHz) with high resolution transducer should be used. US investigation of the shoulder includes scanning of the long head of the biceps, the subskapularis, the supraspinatus, and the infraspinatus tendon in longitudinal and transverse planes, and scanning of the subacromial-subdeltoid (SA/SD) bursa, glenohumeral (GH) and acromioclavicular (AC)joint. The most frequent US findings of the shoulder are effusion in the long head of the biceps tendon, and in the SA/SD bursa, tendinosis or tear of the supraspinatus tendon, and the degenerative changes of the AC joint. In inflammatory arthopahies synovial effusion and hypertrophy of the GH joint can be evaluated. Power Doppler sonography is used for detection of sinovial vascularisation. In this paper standardized techinque for the US examination of the shoulder is described. Pictures of normal and sam basic phathological findings are presented.

  10. Transvaginal 3-d power Doppler ultrasound evaluation of the fetal brain at 10-13 weeks' gestation.

    PubMed

    Hata, Toshiyuki; Tanaka, Hirokazu; Noguchi, Junko

    2012-03-01

    The objective of this study was to measure the fetal brain volume (FBV) and vascularization and blood flow using transvaginal 3-D power Doppler (3DPD) ultrasound late in the first trimester of pregnancy. 3DPD ultrasound examinations with the VOCAL imaging analysis program were performed on 36 normal fetuses from 10-13 weeks' gestation. FBV and 3DPD indices related to the fetal brain vascularization (vascularization index [VI], flow index [FI] and vascularization flow index [VFI]) were calculated in each fetus. Intra- and interclass correlation coefficients and intra- and interobserver agreements of measurements were assessed. FBV was curvilinearly correlated well with the gestational age (R2 = 0.861, p < 0.0001). All 3-D power Doppler indices (VI, FI and VFI) showed no change at 10-13 weeks' gestation. FBV and all 3-D power Doppler indices (VI, FI and VFI) showed a correlation > 0.82, with good intra- and interobserver agreement. Our findings suggest that 3-D ultrasound is a superior means of evaluating the FBV in utero, and that 3-D power Doppler ultrasound histogram analysis may provide new information on the assessment of fetal brain perfusion.

  11. Intra- and Inter-rater Reliability of Peripheral Arterial Blood Flow Velocity by Means of Doppler Ultrasound.

    PubMed

    Guirro, Elaine Caldeira de Oliveira; Leite, Gabriella de Paula Marcondes Ferreira; Dibai-Filho, Almir Vieira; Borges, Nathalia Cristina de Souza; Guirro, Rinaldo Roberto de Jesus

    2017-05-01

    Although it is possible to find studies that analyze the velocity of blood flow in different arteries, the reliability of Doppler ultrasound on peripheral arteries has not yet been completely established. Our objective was to evaluate intra- and inter-rater reliability of the measurement of blood flow velocity by Doppler ultrasound of brachial, radial, popliteal, and posterior tibial arteries. Fifty healthy individuals of both genders, aged between 18 and 45 years, were included in the study. For the evaluation of arterial blood flow velocity, a portable Doppler ultrasound device was used to measure the mean and maximum blood flow velocity of posterior tibial, popliteal, brachial, and radial arteries. Two examiners performed assessments of the same volunteers independently and twice, with an interval of 1 week between them. We found good to very good reliability for measuring the mean and maximum blood flow velocity of the arteries evaluated. The intraclass correlation coefficients ranged between 0.501 and 0.866, standard error of measurement ranged between 0.81 and 9.45 cm/s, and minimum detectable change ranged between 2.25 and 26.13 cm/s. The assessment of mean and maximum blood flow velocity of the brachial, radial, popliteal, and posterior tibial arteries by means of Doppler ultrasound presents acceptable reliability values, which supports the use of this evaluation method in research and clinical practice. Copyright © 2017. Published by Elsevier Inc.

  12. Ultrasound probe and needle-guide calibration for robotic ultrasound scanning and needle targeting.

    PubMed

    Kim, Chunwoo; Chang, Doyoung; Petrisor, Doru; Chirikjian, Gregory; Han, Misop; Stoianovici, Dan

    2013-06-01

    Image-to-robot registration is a typical step for robotic image-guided interventions. If the imaging device uses a portable imaging probe that is held by a robot, this registration is constant and has been commonly named probe calibration. The same applies to probes tracked by a position measurement device. We report a calibration method for 2-D ultrasound probes using robotic manipulation and a planar calibration rig. Moreover, a needle guide that is attached to the probe is also calibrated for ultrasound-guided needle targeting. The method is applied to a transrectal ultrasound (TRUS) probe for robot-assisted prostate biopsy. Validation experiments include TRUS-guided needle targeting accuracy tests. This paper outlines the entire process from the calibration to image-guided targeting. Freehand TRUS-guided prostate biopsy is the primary method of diagnosing prostate cancer, with over 1.2 million procedures performed annually in the U.S. alone. However, freehand biopsy is a highly challenging procedure with subjective quality control. As such, biopsy devices are emerging to assist the physician. Here, we present a method that uses robotic TRUS manipulation. A 2-D TRUS probe is supported by a 4-degree-of-freedom robot. The robot performs ultrasound scanning, enabling 3-D reconstructions. Based on the images, the robot orients a needle guide on target for biopsy. The biopsy is acquired manually through the guide. In vitro tests showed that the 3-D images were geometrically accurate, and an image-based needle targeting accuracy was 1.55 mm. These validate the probe calibration presented and the overall robotic system for needle targeting. Targeting accuracy is sufficient for targeting small, clinically significant prostatic cancer lesions, but actual in vivo targeting will include additional error components that will have to be determined.

  13. Transcranial Doppler ultrasound in the diagnosis of brain death. Is it useful or does it delay the diagnosis?

    PubMed

    Escudero, D; Otero, J; Quindós, B; Viña, L

    2015-05-01

    Transcranial Doppler ultrasound is able to demonstrate cerebral circulatory arrest associated to brain death, being especially useful in sedated patients, or in those in which complete neurological exploration is not possible. Transcranial Doppler ulstrasound is a portable, noninvasive and high-availability technique. Among its limitations, mention must be made of the absence of acoustic windows and false-negative cases. In patients clinically diagnosed with brain death, with open skulls or with anoxia as the cause of death, cerebral blood flow can be observed by ultrasound, since cerebral circulatory arrest is not always synchronized to the clinical diagnosis. The diagnostic rate is therefore time-dependent, and this fact that must be recognized in order to avoid delays in death certification. Despite its limitations, transcranial Doppler ulstrasound helps solve common diagnostic problems, avoids the unnecessary consumption of resources, and can optimize organ harvesting for transplantation.

  14. Instrument configuration for dual-Doppler lidar coplanar scans: METCRAX II

    NASA Astrophysics Data System (ADS)

    Cherukuru, Nihanth Wagmi; Calhoun, Ronald; Lehner, Manuela; Hoch, Sebastian W.; Whiteman, C. David

    2015-01-01

    The second Meteor Crater Experiment (METCRAX II) was designed to study downslope-windstorm-type flows occurring at the Barringer Meteorite Crater in Arizona. Two Doppler wind lidars were deployed to perform a coplanar dual-Doppler lidar analysis to capture the two-dimensional (2-D) vertical structure of these flows in the crater basin. This type of analysis allows the flow to be resolved on a 2-D Cartesian grid constructed in the range height indicator scan overlap region. Previous studies have shown that the dominant error in the coplanar dual-Doppler analysis mentioned above is due to the under sampling of radial velocities. Hence, it is necessary to optimize the setup and choose a scan strategy that minimizes the under sampling of radial velocities and provides a good spatial as well as temporal coverage of these short-lived events. A lidar simulator was developed using a large Eddy simulation wind field to optimize the lidar parameters for METCRAX II field experiment. A retrieval technique based on the weighted least squares technique with weights calculated based on the relative location of the lidar range gate centers to the grid intersection point was developed. The instrument configuration was determined by comparing the simulator retrievals to the background wind field and taking into account the limitations of commercially available lidars.

  15. Resolving the lateral component of blood flow velocity based on ultrasound speckle size change with scan direction and speed.

    PubMed

    Xu, Tiantian; Bashford, Gregory R

    2009-01-01

    Conventional blood flow velocity measurement using ultrasound is capable of resolving the axial component (i.e., that aligned with the ultrasound propagation direction) of the blood flow velocity vector. However, these Doppler-based methods are incapable of detecting blood flow in the direction normal to the ultrasound beam. In addition, these methods require repeated pulse-echo interrogation at the same spatial location. In this paper, we introduce a method which estimates the lateral component of blood flow within a single image frame using the observation that the speckle pattern corresponding to the blood reflectors (typically red blood cells) stretches (i.e., is "smeared") if the blood is moving in the same direction as the electronically-controlled transducer line selection in a 2D image. The situation is analogous to the observed elongation of a subject photographed with a moving camera. Here, we develop a relationship between speckle size, scan speed, and blood flow velocity. Experiments were performed with a blood flow phantom and high-frequency transducer of a commercially available ultrasound machine. Data was captured through an interface allowing access to the raw beam formed data. Blood flow with velocities ranging from 15 to 40 cm/s were investigated in this paper. Results show that there is a linear relationship between the reciprocal of the stretch factor and blood flow velocity. Two scan speeds were used in our experiments. When the scan velocity is 64.8 cm/s, compared with the theoretical model, fitting results based on experimental data gave us a linear relationship with average flow estimation error of 1.74+/-1.48 cm/s. When the scan velocity is 37.4 cm/s, the average estimation error is 0.65+/-0.45 cm/s.

  16. Nondestructive evaluation of composite materials via scanning laser ultrasound spectroscopy

    NASA Astrophysics Data System (ADS)

    Koskelo, Elise Anne C.; Flynn, Eric B.

    2017-04-01

    Composite materials pose a complex problem for ultrasonic nondestructive evaluation due to their unique material properties, greater damping, and often complicated geometry. In this study, we explored acoustic wavenumber spectroscopy (AWS) as a means of rapid inspection of laminate and honeycomb composites. Each aerospace sample was tested at different ultrasonic frequencies using steady-state excitation via a piezo electric actuator. We measured the velocity response of the composite at each pixel via a raster scan using a laser Doppler vibrometer. We were able to detect radial inserts along corners, delamination, and facing-core separation by analyzing local amplitude and wavenumber responses. For each honeycomb composite, we excited the sample at the first resonant frequency of the individual cells. The local mode shape for each cell was extracted from the local amplitude response. Analyzing local amplitude and phase responses for each cell provided an accurate indication as to the presence, size, shape, and type of defect present in the composite. We detected both delamination and deformation of cells within a honeycomb composite. For the laminar composites, we analyzed the non-resonance steady-state response at several excitation frequencies.

  17. Transcranial Doppler Ultrasound: Physical Principles and Principal Applications in Neurocritical Care Unit

    PubMed Central

    D’Andrea, Antonello; Conte, Marianna; Scarafile, Raffaella; Riegler, Lucia; Cocchia, Rosangela; Pezzullo, Enrica; Cavallaro, Massimo; Carbone, Andreina; Natale, Francesco; Russo, Maria Giovanna; Gregorio, Giovanni; Calabrò, Raffaele

    2016-01-01

    Transcranial Doppler (TCD) ultrasonography is a noninvasive ultrasound study, which has been extensively applied on both outpatient and inpatient settings. It involves the use of a low-frequency (≤2 MHz) transducer, placed on the scalp, to insonate the basal cerebral arteries through relatively thin bone windows and to measure the cerebral blood flow velocity and its alteration in many different conditions. In neurointensive care setting, TCD is useful for both adults and children for day-to-day bedside assessment of critical conditions including vasospasm in subarachnoid hemorrhage, traumatic brain injury, acute ischemic stroke, and brain stem death. It also allows to investigate the cerebrovascular autoregulation in setting of carotid disease and syncope. In this review, we will describe physical principles underlying TCD, flow indices most frequently used in clinical practice and critical care applications in Neurocritical Unit care. PMID:28465958

  18. Non-invasive estimation of pulmonary artery systolic pressure with Doppler ultrasound.

    PubMed Central

    Hatle, L; Angelsen, B A; Tromsdal, A

    1981-01-01

    Systolic pressure in the pulmonary artery was estimated from the interval between pulmonary valve closure and tricuspid valve opening, and the heart rate using a nomogram previously described. The timing of valve movements was recorded by Doppler ultrasound. The estimated pressure correlated well with that obtained at catheterisation in 45 of 48 patients with pulmonary hypertension. Instantaneous variations in pressure and changes with treatment and during exercise could be measured. The method was easy to apply in all age groups, and was found useful both in detecting pulmonary hypertension and in the follow-up of patients. It may help to determine the optimal time for surgery or the effect of treatment. PMID:7459175

  19. Acoustical imaging and processing of blood vessel and the related materials using ultrasound Doppler effect.

    PubMed

    Yokobori, A T; Ohkuma, T; Yoshinari, H; Yokobori, T; Ohuchi, H; Mori, S

    1991-01-01

    In the present paper a method is proposed to measure the degree of the degradation of the elasticity in natural blood vessel and the related materials by using ultrasound Doppler effect. It was found that the deformation rate and its acceleration in the radial direction of the blood vessel can be detected by acoustical imaging and processing using this method. These results were proven to correspond to the degree of the degradation of the elasticity, that is, the degree of viscoelasticity in the blood vessel from the wave versus time pattern detected and its simple analysis. This method was applied to predicting the arteriosclerosis of blood vessels of humans by acoustical imaging and processing uninvadedly, as the characteristics of viscoelasticity in blood vessels.

  20. Atypical cerebral lateralisation in adults with compensated developmental dyslexia demonstrated using functional transcranial Doppler ultrasound

    PubMed Central

    Illingworth, Sarah; Bishop, Dorothy V.M.

    2009-01-01

    Functional transcranial Doppler ultrasound (fTCD) is a relatively new and non-invasive technique that assesses cerebral lateralisation through measurements of blood flow velocity in the middle cerebral arteries. In this study fTCD was used to compare functional asymmetry during a word generation task between a group of 30 dyslexic adults and a group of 30 non-dyslexic individuals. In light of previous evidence of atypical laterality in dyslexia, a reduced leftward asymmetry was predicted and confirmed. We know from previous research that most people with atypical language lateralisation have normal language and literacy skills: nevertheless, our results confirm that language laterality is reduced in those with dyslexia. Theoretical explanations for this apparent conundrum are discussed. PMID:19525003

  1. Modelflow Estimates of Stroke Volume Do Not Correlate With Doppler Ultrasound Estimates During Upright Posture

    NASA Technical Reports Server (NTRS)

    Ferguson, Connor R.; Lee, Stuart M. C.; Stenger, Michael B.; Platts, Steven H.; Laurie, Steven S.

    2014-01-01

    Orthostatic intolerance affects 60-80% of astronauts returning from long-duration missions, representing a significant risk to completing mission-critical tasks. While likely multifactorial, a reduction in stroke volume (SV) represents one factor contributing to orthostatic intolerance during stand and head up tilt (HUT) tests. Current measures of SV during stand or HUT tests use Doppler ultrasound and require a trained operator and specialized equipment, restricting its use in the field. BeatScope (Finapres Medical Systems BV, The Netherlands) uses a modelflow algorithm to estimate SV from continuous blood pressure waveforms in supine subjects; however, evidence supporting the use of Modelflow to estimate SV in subjects completing stand or HUT tests remain scarce. Furthermore, because the blood pressure device is held extended at heart level during HUT tests, but allowed to rest at the side during stand tests, changes in the finger arterial pressure waveform resulting from arm positioning could alter modelflow estimated SV. The purpose of this project was to compare Doppler ultrasound and BeatScope estimations of SV to determine if BeatScope can be used during stand or HUT tests. Finger photoplethysmography was used to acquire arterial pressure waveforms corrected for hydrostatic finger-to-heart height using the Finometer (FM) and Portapres (PP) arterial pressure devices in 10 subjects (5 men and 5 women) during a stand test while simultaneous estimates of SV were collected using Doppler ultrasound. Measures were made after 5 minutes of supine rest and while subjects stood for 5 minutes. Next, SV estimates were reacquired while each arm was independently raised to heart level, a position similar to tilt testing. Supine SV estimates were not significantly different between all three devices (FM: 68+/-20, PP: 71+/-21, US: 73+/-21 ml/beat). Upon standing, the change in SV estimated by FM (-18+/-8 ml) was not different from PP (-21+/-12), but both were significantly

  2. Evaluation of a fractional filter-based receive beamforming method for low-cost ultrasound color Doppler imaging

    NASA Astrophysics Data System (ADS)

    Yang, Hana; Kang, Jeeun; Chang, Jin Ho; Yoo, Yangmo

    2012-03-01

    In medical ultrasound imaging, dynamic receive beamforming has been used for improving signal-to-noise ratio (SNR) and spatial resolution. For low-cost portable ultrasound imaging systems, a fractional filter-based receive beamforming (FFRB) method was previously proposed to reduce the hardware complexity compared to conventional interpolation filter-based receive beamforming methods (IFRB). While this new beamforming method substantially reduces the hardware complexity, it yields the nonlinear phase response for high frequencies due to the limited length of fractional filter coefficients, leading to the bias on flow estimation in ultrasound color Doppler imaging. In this paper, to evaluate the FFRB method for ultrasound color Doppler imaging, the Field II simulation and string phantom experiments were conducted. In Field II simulation, the radio-frequency (RF) data were generated by assuming a 7.5-MHz linear array probe with the transmit frequency of 6 MHz, the ensemble size of 8, and the sampling frequencies of 20 MHz. In string phantom experiments, the RF channel data were obtained with a commercial SonixTouch ultrasound scanner equipped with a research package (Ultrasonix Corp., Vancouver, BC, Canada; a 5-MHz linear array connected to a SonixDAQ parallel system. The ensemble size and the sampling frequency were set to 10 and 20 MHz, respectively. For the Field II simulation and string phantom experiments, only 1.2% and 2.3 % in color Doppler estimation error ratio was observed with mean and standard deviation along the lateral direction. This result indicates that the proposed FFRB method could be utilized for a low-cost ultrasound color Doppler imaging system with lowered hardware complexity and minimized phase errors.

  3. Low-level mixing height detection in coastal locations with a scanning Doppler lidar

    NASA Astrophysics Data System (ADS)

    Vakkari, V.; O'Connor, E. J.; Nisantzi, A.; Mamouri, R. E.; Hadjimitsis, D. G.

    2015-04-01

    Mixing layer height (MLH) is one of the key parameters in describing lower tropospheric dynamics and capturing its diurnal variability is crucial, especially for interpreting surface observations. In this paper we introduce a method for identifying MLH below the minimum range of a scanning Doppler lidar when operated at vertical. The method we propose is based on velocity variance in low-elevation-angle conical scanning and is applied to measurements in two very different coastal environments: Limassol, Cyprus, during summer and Loviisa, Finland, during winter. At both locations, the new method agrees well with MLH derived from turbulent kinetic energy dissipation rate profiles obtained from vertically pointing measurements. The low-level scanning routine frequently indicated non-zero MLH less than 100 m above the surface. Such low MLHs were more common in wintertime Loviisa on the Baltic Sea coast than during summertime in Mediterranean Limassol.

  4. A Microfluidics-based Pulpal Arteriole Blood Flow Phantom for Validation of Doppler Ultrasound Devices in Pulpal Blood Flow Velocity Measurement.

    PubMed

    Kim, Dohyun; Park, Sung-Ho

    2016-11-01

    Recently, Doppler ultrasound has been used for the measurement of pulpal blood flow in human teeth. However, the reliability of this method has not been verified. In this study, we developed a model to simulate arteriole blood flow within the dental pulp by using microfluidics. This arteriole simulator, or flow phantom, was used to determine the reliability of measurements obtained by using a Doppler ultrasound device. A microfluidic chip was fabricated by using the soft lithography technique, and blood-mimicking fluid was pumped through the channel by a microfluidic system. A Doppler ultrasound device was used for the measurement of flow velocity. The peak, mean, and minimal flow velocities obtained from the phantom and the Doppler ultrasound device were compared by using linear regression analysis and Pearson correlation coefficient. Bland-Altman analyses were performed to evaluate the velocity differences between the flow generated by the phantom and the flow measurements made with the Doppler ultrasound device. The microfluidic system was able to generate the flow profiles as intended, and the fluid flow could be monitored and controlled by the software program. There were excellent linear correlations between the peak, mean, and minimal flow velocities of the phantom and those of the Doppler ultrasound device (r = 0.94-0.996, P < .001). However, the velocities were overestimated by the Doppler ultrasound device. This phantom provides opportunities for research and education involving the Doppler ultrasound technique in dentistry. Although Doppler ultrasound can be an effective tool for the measurement of pulpal blood flow velocity, it is essential to validate and calibrate the device before clinical use. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  5. Axial scanning laser Doppler velocimeter using wavelength change without moving mechanism in sensor probe.

    PubMed

    Maru, Koichi

    2011-03-28

    A scanning laser Doppler velocimeter (LDV) without any moving mechanism in its sensor probe is proposed. In the proposed scanning LDV, the measurement position is axially scanned by change in the wavelength of the light input to the sensor probe, instead of using a moving mechanism in the sensor probe. For this purpose, a tunable laser and diffraction gratings are used, and the sensor probe including the gratings is separated from the main body including the tunable laser. To demonstrate the scanning function based on the proposed concept, an experiment was conducted using optical fibers, a commercial tunable laser and a setup of the sensor probe consisting of bulk optical components. As the experimental result, it is found that the measurement positions estimated from the measured beat frequencies are in good agreement with the theoretical values. The scan ranges over a wavelength range of 30 nm are estimated to be 29.3 mm when the beam angle to the measurement position at the wavelength of 1540 nm is 10° and 20.8 mm when the beam angle is 15°. The result indicates that the scanning function by means of changing the wavelength input to the sensor probe is successfully demonstrated for the first time. The proposed method has the potential for realizing a scanning LDV with a simple, compact and reliable sensor probe.

  6. Improved ultrasound transducer positioning by fetal heart location estimation during Doppler based heart rate measurements.

    PubMed

    Hamelmann, Paul; Vullings, Rik; Schmitt, Lars; Kolen, Alexander Franciscus; Mischi, Massimo; Van Laar, Judith O E H; Bergmans, Jan W M

    2017-09-04

    Doppler Ultrasound (US) is the most commonly applied method to measure the fetal heart rate (fHR). When the fetal heart is not properly located within the ultrasonic beam, fHR measurements often fail. As a consequence, clinical staff needs to reposition the US transducer on the maternal abdomen, which can be a time consuming and tedious task. In this article, a method is presented to aid clinicians with the positioning of the US transducer to produce robust fHR measurements. A maximum likelihood estimation (MLE) algorithm is developed, which provides information on fetal heart location using the power of the Doppler signals received in the individual elements of a standard US transducer for fHR recordings. The performance of the algorithm is evaluated with simulations and in-vitro experiments performed on a beating-heart setup. Both the experiments and the simulations show that the heart location can be accurately determined with an error of less than 7 mm within the measurement volume of the employed US transducer. The results show that the developed algorithm can be used to provide accurate feedback on fetal heart location for improved positioning of the US transducer, which may lead to improved measurements of the fHR. © 2017 Institute of Physics and Engineering in Medicine.

  7. Myocardial tissue Doppler velocity imaging in children: comparative study between two ultrasound systems.

    PubMed

    Koopman, Laurens P; Slorach, Cameron; Manlhiot, Cedric; McCrindle, Brian W; Friedberg, Mark K; Mertens, Luc; Jaeggi, Edgar T

    2010-09-01

    The investigators compared pulsed-wave tissue Doppler (PWTD) and color tissue Doppler (CTD) ventricular tissue velocities obtained using Vivid 7 (GE) and iE33 (Philips) ultrasound systems within a 30-minute time frame and examined interobserver and intraobserver variability. Longitudinal PWTD and CTD images were prospectively acquired in 49 children from the base of the right and left ventricular free wall and septum and stored for offline analysis. Intraobserver and interobserver coefficients of variation for PWTD velocities ranged from 4% to 6% and 5% to 10% for GE and from 1% to 10% and 2% to 14% for Philips, respectively. Intraobserver and interobserver coefficients of variation for CTD velocities ranged from 4% to 15% and 6% to 24% for GE and from 6% to 19% and 7% to 25% for Philips, respectively. Mean biases between the two systems for PWTD velocities, expressed as percentage differences, were around 0%, with the narrowest limits of agreement for systolic velocities at the septal annulus and the widest limits of agreement for early diastolic velocities at the lateral tricuspid valve annulus, respectively. Peak CTD-derived velocities were significantly and consistently lower for Philips compared with GE. Agreement between GE-derived and Philips-derived PWTD velocities was reasonable, whereas CTD-derived velocities differed substantially. 2010 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.

  8. In vitro Doppler ultrasound investigation of turbulence intensity in pulsatile flow with simulated cardiac variability.

    PubMed

    Thorne, Meghan L; Poepping, Tamie L; Nikolov, Hristo N; Rankin, Richard N; Steinman, David A; Holdsworth, David W

    2009-01-01

    An in vitro investigation of turbulence intensity (TI) associated with a severe carotid stenosis in the presence of physiological cardiac variability is described. The objective of this investigation was to determine if fluctuations due to turbulence could be quantified with conventional Doppler ultrasound (DUS) in the presence of normal physiological cycle-to-cycle cardiac variability. An anthropomorphic model of a 70% stenosed carotid bifurcation was used in combination with a programmable flow pump to generate pulsatile flow with a mean flow rate of 6 mL/s. Utilizing the pump, we studied normal, nonrepetitive cycle-to-cycle cardiac variability (+/-3.9%) in flow, as well as waveform shapes with standard deviations equal to 0, 2 and 3 times the normal variation. Eighty cardiac cycles of Doppler data were acquired at two regions within the model, representing either laminar or turbulent flow; each measurement was repeated six times. Turbulence intensity values were found to be 11 times higher (p < 0.001), on average, in the turbulent region than in the laminar region, with a mean difference of 24 cm/s. Twenty cardiac cycles were required for confidence in TI values. In conclusion, these results indicate that it is possible to quantify TI in vitro, even in the presence of normal and exaggerated cycle-to-cycle cardiac variability.

  9. Doppler ultrasound in vitro modeling of turbulence in carotid vascular disease

    NASA Astrophysics Data System (ADS)

    Thorne, Meghan L.; Poepping, Tamie L.; Rankin, Richard N.; Nikolov, Hristo N.; Holdsworth, David W.

    2004-04-01

    Turbulence is ubiquitous to many systems in nature, except the human vasculature. Development of turbulence in the human vasculature is an indication of abnormalities and disease. A severely stenosed vessel is one such example. In vitro modeling of common vascular diseases, such as a stenosis, is necessary to develop a better understanding of the fluid dynamics for a characteristic geometry. Doppler ultrasound (DUS) is the only available non-invasive technique for in vivo applications. Using Doppler velocity-derived data, turbulence intensity (TI) can be calculated. We investigate a realistic 70% stenosed bifurcation model in pulsatile flow and the performance of this model for turbulent flow. Blood-mimicking fluid (BMF) was pumped through the model using a flow simulator, which generated pulsatile flow with a mean flow rate of 6 ml/s. Twenty-five cycles of gated DUS data were acquired within regions of laminar and turbulent flow. The data was digitized at 44.1 kHz and analyzed at 79 time-points/cardiac cycle with a 1024-point FFT, producing a 1.33 cm/s velocity resolution. We found BMF to exhibit DUS characteristics similar to blood. We demonstrated the capabilities to generate velocities comparable to that found in the human carotid artery and calculated TI in the case of repetitive pulsatile flow.

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

    PubMed

    Spatola, Leonardo; Andrulli, Simeone

    2016-12-01

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

  11. Doppler ultrasound compatible plastic material for use in rigid flow models.

    PubMed

    Wong, Emily Y; Thorne, Meghan L; Nikolov, Hristo N; Poepping, Tamie L; Holdsworth, David W

    2008-11-01

    A technique for the rapid but accurate fabrication of multiple flow phantoms with variations in vascular geometry would be desirable in the investigation of carotid atherosclerosis. This study demonstrates the feasibility and efficacy of implementing numerically controlled direct-machining of vascular geometries into Doppler ultrasound (DUS)-compatible plastic for the easy fabrication of DUS flow phantoms. Candidate plastics were tested for longitudinal speed of sound (SoS) and acoustic attenuation at the diagnostic frequency of 5 MHz. Teflon was found to have the most appropriate SoS (1376 +/- 40 m s(-1) compared with 1540 m s(-1) in soft tissue) and thus was selected to construct a carotid bifurcation flow model with moderate eccentric stenosis. The vessel geometry was machined directly into Teflon using a numerically controlled milling technique. Geometric accuracy of the phantom lumen was verified using nondestructive micro-computed tomography. Although Teflon displayed a higher attenuation coefficient than other tested materials, Doppler data acquired in the Teflon flow model indicated that sufficient signal power was delivered throughout the depth of the vessel and provided comparable velocity profiles to that obtained in the tissue-mimicking phantom. Our results indicate that Teflon provides the best combination of machinability and DUS compatibility, making it an appropriate choice for the fabrication of rigid DUS flow models using a direct-machining method.

  12. Consensus-based identification of factors related to false-positives in ultrasound scanning of synovitis and tenosynovitis.

    PubMed

    Ikeda, Kei; Narita, Akihiro; Ogasawara, Michihiro; Ohno, Shigeru; Kawahito, Yutaka; Kawakami, Atsushi; Ito, Hiromu; Matsushita, Isao; Suzuki, Takeshi; Misaki, Kenta; Ogura, Takehisa; Kamishima, Tamotsu; Seto, Yohei; Nakahara, Ryuichi; Kaneko, Atsushi; Nakamura, Takayuki; Henmi, Mihoko; Fukae, Jun; Nishida, Keiichiro; Sumida, Takayuki; Koike, Takao

    2016-01-01

    We aimed to identify causes of false-positives in ultrasound scanning of synovial/tenosynovial/bursal inflammation and provide corresponding imaging examples. We first performed systematic literature review to identify previously reported causes of false-positives. We next determined causes of false-positives and corresponding example images for educational material through Delphi exercises and discussion by 15 experts who were an instructor and/or a lecturer in the 2013 advanced course for musculoskeletal ultrasound organized by Japan College of Rheumatology Committee for the Standardization of Musculoskeletal Ultrasonography. Systematic literature review identified 11 articles relevant to sonographic false-positives of synovial/tenosynovial inflammation. Based on these studies, 21 candidate causes of false-positives were identified in the consensus meeting. Of these items, 11 achieved a predefined consensus (≥ 80%) in Delphi exercise and were classified as follows: (I) Gray-scale assessment [(A) non-specific synovial findings and (B) normal anatomical structures which can mimic synovial lesions due to either their low echogenicity or anisotropy]; (II) Doppler assessment [(A) Intra-articular normal vessels and (B) reverberation)]. Twenty-four corresponding examples with 49 still and 23 video images also achieved consensus. Our study provides a set of representative images that can help sonographers to understand false-positives in ultrasound scanning of synovitis and tenosynovitis.

  13. Field Evaluation in Four NEEMO Divers of a Prototype In-suit Doppler Ultrasound Bubble Detector

    NASA Technical Reports Server (NTRS)

    Acock, K. E.; Gernhardt, M. L.; Conkin, J.; Powell, M. R.

    2004-01-01

    It is desirable to know if astronauts produce venous gas emboli (VGE) as a result of their exposure to 4.3 psia during space walks. The current prototype in-suit Doppler (ISD) ultrasound bubble detector provides an objective assessment of decompression stress by monitoring for VGE. The NOAA Aquarius habitat and NASA Extreme Environment Mission Operations (NEEMO) series of dives provided an opportunity to assess the ability of the prototype ISDs to record venous blood flow and possibly detect VGE in the pulmonary artery. From July 16 to 29,2003, four aquanauts (two males and two females) donned the ISD for a 4 hr automated recording session, following excursion dives (up to 6hrs and 29 MSW below storage depth) from air saturation at 17 MSW. Doppler recordings for 32 excursion dives were collected. The recordings consisted of approximately 150 digital wave files. Each wave file contained 24 sec of recording for each min. A 1 - 4 Doppler Quality Score (DQS) was assigned to each wave file in 17 of the 32 records evaluated to date. A DQS of 1 indicates a poor flow signal and a score of 4 indicates an optimum signal. Only 23% of all wave files had DQSs considered adequate to detect low grade VGE (Spencer I-II). The distribution of DQS in 2,356 wave files is as follows: DQS 1-56%, DQS 2-21%, DQS 3-18% and DQS 4-5%. Six of the 17 records had false positive VGE (Spencer I-IV) detected in one or more wave files per dive record. The false positive VGE recordings are attributable to air entrainment associated with drinking (verified by control tests), and this observation is important as astronauts drink water during space walks. The current ISD design provides quality recordings only over a narrow range of chest anatomy.

  14. Arterial pulse wave propagation velocity in healthy dogs by pulse wave Doppler ultrasound.

    PubMed

    Nogueira, Rodrigo B; Pereira, Lucas A; Basso, Alice F; da Fonseca, Ingrid S; Alves, Lorena A

    2017-03-01

    The aim of this study was to prospectively evaluate the carotid-femoral pulse wave velocity (PWV) values in healthy dogs using pulse wave Doppler ultrasound. A secondary aim was to determine the feasibility of this method and to report the intra- and interobserver reproducibilities of the PWV in conscious dogs. The data were studied in 30 healthy, adult, male (n = 15) and female (n = 15) dogs. The time interval marked between the R wave peak of the electrocardiogram and the intersection of the blood flow wave upstroke of the Doppler spectrum with the baseline of zero frequency was determined for the carotid (T1) and for the femoral (T2) arteries. The distance covered by the pulse wave (L) was determined. The PWV was then calculated using the following formula: L/T2 - T1. The mean values of PWV calculated from the total sample (n = 30) evaluated were 13.41 ± 2.20 m/s. No significant statistical difference was observed for the PWV measurements between males (14.82 ± 3.18 m/s) and females (12.64 ± 2.45 m/s). The analysis revealed no intra nor interobserver differences. A reasonable reproducibility of the PWV measurements was showed by intraclass correlation coefficients (ICC), and the coefficients of variation (CV). These data demonstrate that noninvasive vascular Doppler analysis is a feasible and reproducible method to determine the carotid-femoral PWV in dogs.

  15. Automated measurement of fetal myocardial performance index in ultrasound Doppler waveforms

    NASA Astrophysics Data System (ADS)

    Yoon, Heechul; Lee, Hyuntaek; Jeon, Kang-Won; Jung, Haekyung; Lee, Mi-Young; Won, Hye-Sung; Jeon, Eun-Jin; Yang, Eun-Ho; Choi, Jin-Young; Hong, Soon-Jae

    2014-03-01

    We introduce an automated method for myocardial performance index (MPI), also known as Tei index, which is one of the most substantial indicators in the early screening of heart defects. Since assessing fetal cardiac functions using MPI has become a routine and significant process, there have been explicit requirements to automate MPI measurements. Due to small heart sizes of fetuses, we focus on the automation of modified MPI (Mod-MPI) which uses a single Doppler gate. The proposed method detects four valve click signals in Doppler waveforms using four image features which are extracted by vertical projection of Doppler waveforms after several transformations. To evaluate performance, 88 of fetal examinations were collected from a commercial ultrasound machine, and two clinical experts measured the Mod-MPI both manually and automatically. Quantitative comparisons based on intra-class correlation coefficients (ICC) yield that intra-observer reproducibility is higher when performing the proposed method (ICC=0.951 and 0.932 for observer 1 and 2) comparing to those of manual measurements (ICC=0.868 and 0.857 for observer 1 and observer 2). Thus, our method (ICC=0.962) reveals superior inter-observer reproducibility than that of manual method (ICC=0.597). Although mean difference from observer 2 (-0.062) is over three times larger than that of observer 1 (-0.018) due to different experiences, both of mean differences are acceptable. In conclusion, the proposed MPI measurement method can improve intra- and inter-reproducibility while providing reliable results.

  16. Field Evaluation in Four NEEMO Divers of a Prototype In-suit Doppler Ultrasound Bubble Detector

    NASA Technical Reports Server (NTRS)

    Acock, K. E.; Gernhardt, M. L.; Conkin, J.; Powell, M. R.

    2004-01-01

    It is desirable to know if astronauts produce venous gas emboli (VGE) as a result of their exposure to 4.3 psia during space walks. The current prototype in-suit Doppler (ISD) ultrasound bubble detector provides an objective assessment of decompression stress by monitoring for VGE. The NOAA Aquarius habitat and NASA Extreme Environment Mission Operations (NEEMO) series of dives provided an opportunity to assess the ability of the prototype ISDs to record venous blood flow and possibly detect VGE in the pulmonary artery. From July 16 to 29,2003, four aquanauts (two males and two females) donned the ISD for a 4 hr automated recording session, following excursion dives (up to 6hrs and 29 MSW below storage depth) from air saturation at 17 MSW. Doppler recordings for 32 excursion dives were collected. The recordings consisted of approximately 150 digital wave files. Each wave file contained 24 sec of recording for each min. A 1 - 4 Doppler Quality Score (DQS) was assigned to each wave file in 17 of the 32 records evaluated to date. A DQS of 1 indicates a poor flow signal and a score of 4 indicates an optimum signal. Only 23% of all wave files had DQSs considered adequate to detect low grade VGE (Spencer I-II). The distribution of DQS in 2,356 wave files is as follows: DQS 1-56%, DQS 2-21%, DQS 3-18% and DQS 4-5%. Six of the 17 records had false positive VGE (Spencer I-IV) detected in one or more wave files per dive record. The false positive VGE recordings are attributable to air entrainment associated with drinking (verified by control tests), and this observation is important as astronauts drink water during space walks. The current ISD design provides quality recordings only over a narrow range of chest anatomy.

  17. Fetal Echocardiography and Pulsed-wave Doppler Ultrasound in a Rabbit Model of Intrauterine Growth Restriction

    PubMed Central

    Hodges, Ryan; Endo, Masayuki; La Gerche, Andre; Eixarch, Elisenda; DeKoninck, Philip; Ferferieva, Vessilina; D'hooge, Jan; Wallace, Euan M.; Deprest, Jan

    2013-01-01

    Fetal intrauterine growth restriction (IUGR) results in abnormal cardiac function that is apparent antenatally due to advances in fetoplacental Doppler ultrasound and fetal echocardiography. Increasingly, these imaging modalities are being employed clinically to examine cardiac function and assess wellbeing in utero, thereby guiding timing of birth decisions. Here, we used a rabbit model of IUGR that allows analysis of cardiac function in a clinically relevant way. Using isoflurane induced anesthesia, IUGR is surgically created at gestational age day 25 by performing a laparotomy, exposing the bicornuate uterus and then ligating 40-50% of uteroplacental vessels supplying each gestational sac in a single uterine horn. The other horn in the rabbit bicornuate uterus serves as internal control fetuses. Then, after recovery at gestational age day 30 (full term), the same rabbit undergoes examination of fetal cardiac function. Anesthesia is induced with ketamine and xylazine intramuscularly, then maintained by a continuous intravenous infusion of ketamine and xylazine to minimize iatrogenic effects on fetal cardiac function. A repeat laparotomy is performed to expose each gestational sac and a microultrasound examination (VisualSonics VEVO 2100) of fetal cardiac function is performed. Placental insufficiency is evident by a raised pulsatility index or an absent or reversed end diastolic flow of the umbilical artery Doppler waveform. The ductus venosus and middle cerebral artery Doppler is then examined. Fetal echocardiography is performed by recording B mode, M mode and flow velocity waveforms in lateral and apical views. Offline calculations determine standard M-mode cardiac variables, tricuspid and mitral annular plane systolic excursion, speckle tracking and strain analysis, modified myocardial performance index and vascular flow velocity waveforms of interest. This small animal model of IUGR therefore affords examination of in utero cardiac function that is

  18. Compounding of ultrasound B-scans of a transfemoral residual limb using a genetic algorithm

    NASA Astrophysics Data System (ADS)

    Douglas, Tania S.; Lee, Peter; Solomonidis, Stephan E.; Spence, William D.

    1998-06-01

    Ultrasound may be used for imaging the trans-femoral residual limb in order to provide information for the improvement of prosthetic socket design. Compounding of several ultrasound B-scans is required for obtaining transverse images of the residual limb. In this paper, a method is presented by which a genetic algorithm is used to match B-scans taken in a horizontal plane around the residual limb for image compounding in order to reduce the effects of patient motion during scanning.

  19. Evaluation of gridded scanning ARM cloud radar reflectivity observations and vertical doppler velocity retrievals

    NASA Astrophysics Data System (ADS)

    Lamer, K.; Tatarevic, A.; Jo, I.; Kollias, P.

    2014-04-01

    The scanning Atmospheric Radiation Measurement (ARM) cloud radars (SACRs) provide continuous atmospheric observations aspiring to capture the 3-D cloud-scale structure. Sampling clouds in 3-D is challenging due to their temporal-spatial scales, the need to sample the sky at high elevations and cloud radar limitations. Thus, a suggested scan strategy is to repetitively slice the atmosphere from horizon to horizon as clouds advect over the radar (Cross-Wind Range-Height Indicator - CW-RHI). Here, the processing and gridding of the SACR CW-RHI scans are presented. First, the SACR sample observations from the ARM Southern Great Plains and Cape Cod sites are post-processed (detection mask, gaseous attenuation correction, insect filtering and velocity de-aliasing). The resulting radial Doppler moment fields are then mapped to Cartesian coordinates with time as one of the dimensions. Next the Cartesian-gridded Doppler velocity fields are decomposed into the horizontal wind velocity contribution and the vertical Doppler velocity component. For validation purposes, all gridded and retrieved fields are compared to collocated zenith-pointing ARM cloud radar measurements. We consider that the SACR sensitivity loss with range, the cloud type observed and the research purpose should be considered in determining the gridded domain size. Our results also demonstrate that the gridded SACR observations resolve the main features of low and high stratiform clouds. It is established that the CW-RHI observations complemented with processing techniques could lead to robust 3-D cloud dynamical representations up to 25-30 degrees off zenith. The proposed gridded products are expected to advance our understanding of 3-D cloud morphology, dynamics and anisotropy and lead to more realistic 3-D radiative transfer calculations.

  20. Two-dimensional ultrasound Doppler velocimeter for flow mapping of unsteady liquid metal flows.

    PubMed

    Franke, S; Lieske, H; Fischer, A; Büttner, L; Czarske, J; Räbiger, D; Eckert, S

    2013-03-01

    We present a novel pulsed-wave ultrasound Doppler system for fluid flow investigations being able to determine two-dimensional vector fields of flow velocities. Electromagnetically-driven liquid metal flows appear as an attractive application field for such a measurement system. Two linear ultrasound transducer arrays each equipped with 25 transducer elements are used to measure the flow field in a square plane of 67×67 mm(2). The application of advanced processing methods as a multi-beam operation, an interlaced echo signal acquisition and a segmental array technique enable high data acquisition rates and concurrently a high spatial resolution, which have not been obtained so far for flow measurements in liquid metals. The extended pulsing strategy and essential operation principles such as the multiplexing electronic concept will be presented within this paper. The capabilities of the measuring system make it suitable for investigations of non-transparent, turbulent flows. Here, we present measurements of liquid metal flows driven by a rotating magnetic field for demonstration purposes. The measuring setup realized here reveals details of the swirling fluid motion in a horizontal section of a cube. Frame acquisition rates up to 30 fps were achieved for a complete two-dimensional flow mapping.

  1. Doppler-scanning tunneling microscopy current imaging in superconductor-ferromagnet hybrids

    SciTech Connect

    Moore, S. A.; Plummer, G.; Fedor, J.; Pearson, J. E.; Novosad, V.; Karapetrov, G.; Iavarone, M.

    2016-01-25

    Mapping the distribution of currents inside a superconductor is usually performed indirectly through imaging of the stray magnetic fields above the surface. Here, we show that by direct imaging of the Doppler shift contribution to the quasiparticle excitation spectrum in the superconductor using low temperature scanning tunneling microscopy, we obtain directly the distribution of supercurrents inside the superconductor. We demonstrate the technique at the example of superconductor/ferromagnet hybrid structure that produces intricate current pattern consisting of combination Meissner shielding currents and Abrikosov vortex currents.

  2. Multi-frequency, 3D ODS measurement by continuous scan laser Doppler vibrometry

    NASA Astrophysics Data System (ADS)

    Weekes, Ben; Ewins, David

    2015-06-01

    Continuous scan laser Doppler vibrometry (CSLDV) is a technique which has been described and explored in the literature for over two decades, but remains niche compared to SLDV inspection by a series of discrete-point measurements. This is in part because of the unavoidable phenomenon of laser speckle, which deteriorates signal quality when velocity data is captured from a moving spot measurement. Further, applicability of CSLDV has typically been limited to line scans and rectangular areas by the application of sine, step, or ramp functions to the scanning mirrors which control the location of the measurement laser spot. In this paper it is shown that arbitrary functions to scan any area can easily be derived from a basic calibration routine, equivalent to the calibration performed in conventional discrete-point laser vibrometry. This is extended by performing the same scan path upon a test surface from three independent locations of the laser head, and decomposing the three sets of one-dimensional deflection shapes into a single set of three-dimensional deflection shapes. The test was performed with multi-sine excitation, yielding 34 operating deflection shapes from each scan.

  3. Comparison of scanning beam and whole field laser Doppler perfusion imaging

    NASA Astrophysics Data System (ADS)

    Steenbergen, Wiendelt; Hondebrink, Erwin; Van Leeuwen, Ton G.; Draijer, Matthijs J.

    2010-02-01

    Currently, laser perfusion imaging (LDPI) is undergoing a technology shift from scanning beam perfusion imagers to whole field systems. The latter can be subdivided in laser Doppler methods systems based on high speed CMOS cameras, and laser speckle contrast analysis (LASCA) technologies using slow imaging arrays, mostly CCD-based. In scanning beam systems, a collimated laser beam scans the tissue with diffusely back reflected light being captured with a single detector. In whole field systems a large tissue area is illuminated, and the reflected light is imaged onto an array and captured at once. Unlike scanning beam systems, both whole field methods enable perfusion imaging at video rate. In this study we experimentally compare the scanning beam LDPI principle with whole field LDPI, using Intralipid phantoms. For the tissue phantoms, the Monte Carlo simulation technique will be used as a reference. From measurements on Intralipid phantoms compared to Monte Carlo, we conclude that in whole field LDPI the flux image, representing the first order moment of the power spectrum of photocurrent fluctuations is much closer related to real perfusion than for scanning beam systems. This difference can be explained in terms of the different behaviour of dynamic speckle patterns generated in both methods, in response to varying tissue optical properties.

  4. A novel technique for fetal heart rate estimation from Doppler ultrasound signal

    PubMed Central

    2011-01-01

    Background The currently used fetal monitoring instrumentation that is based on Doppler ultrasound technique provides the fetal heart rate (FHR) signal with limited accuracy. It is particularly noticeable as significant decrease of clinically important feature - the variability of FHR signal. The aim of our work was to develop a novel efficient technique for processing of the ultrasound signal, which could estimate the cardiac cycle duration with accuracy comparable to a direct electrocardiography. Methods We have proposed a new technique which provides the true beat-to-beat values of the FHR signal through multiple measurement of a given cardiac cycle in the ultrasound signal. The method consists in three steps: the dynamic adjustment of autocorrelation window, the adaptive autocorrelation peak detection and determination of beat-to-beat intervals. The estimated fetal heart rate values and calculated indices describing variability of FHR, were compared to the reference data obtained from the direct fetal electrocardiogram, as well as to another method for FHR estimation. Results The results revealed that our method increases the accuracy in comparison to currently used fetal monitoring instrumentation, and thus enables to calculate reliable parameters describing the variability of FHR. Relating these results to the other method for FHR estimation we showed that in our approach a much lower number of measured cardiac cycles was rejected as being invalid. Conclusions The proposed method for fetal heart rate determination on a beat-to-beat basis offers a high accuracy of the heart interval measurement enabling reliable quantitative assessment of the FHR variability, at the same time reducing the number of invalid cardiac cycle measurements. PMID:21999764

  5. Angiogenic Factors and Doppler Evaluation in Normally Growing Fetuses at Routine Third-Trimester Scan: Prediction of Subsequent Low Birth Weight.

    PubMed

    Triunfo, Stefania; Parra-Saavedra, Miguel; Rodriguez-Sureda, Victor; Crovetto, Francesca; Dominguez, Carmen; Gratacós, Eduard; Figueras, Francesc

    2016-01-01

    To evaluate in normally growing fetuses at routine 32-36 weeks scan the performance of maternal angiogenic factors, Doppler and ultrasound indices in predicting smallness for gestational age (SGA) at birth. A cohort of 1,000 singleton pregnancies with normal estimated fetal weight (EFW, ≥10th centile) at 32-36 weeks scan was included. At inclusion, Doppler indices (mean uterine artery pulsatility index [mUtA-PI], cerebroplacental ratio and normalized umbilical vein blood flow by EFW (ml/min/kg) were evaluated, and blood samples were collected and frozen. Nested in this cohort, maternal circulating placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) were assayed by enzyme-linked immunosorbent assay in all cases with a birth weight <10th centile by customized standards and in an equivalent number of controls (birth weight ≥10th centile). 160 cases were included (80 SGA and 80 controls). EFW (2,128 vs. 2,279 g, p < 0.001), mUtA-PI z-values (-0.25 vs. -0.65, p = 0.034) and sFlt-1/PlGF ratio (11.10 vs. 6.74, p < 0.005) were lower in SGA. The combination of sFlt-1/PlGF ratio and EFW resulted in a 66.3% detection rate for subsequent SGA, with 20% of false-positives. Fetal Doppler indices were not predictive of SGA. In normally growing fetuses, maternal angiogenic factors add to ultrasound parameters in predicting subsequent SGA at birth. This supports further research to investigate composite scores in order to improve the definition and identification of fetal growth restriction. © 2015 S. Karger AG, Basel.

  6. Multi-centre clinical study evaluating the efficacy of SonoVue (BR1), a new ultrasound contrast agent in Doppler investigation of focal hepatic lesions.

    PubMed

    Leen, E; Angerson, W J; Yarmenitis, S; Bongartz, G; Blomley, M; Del Maschio, A; Summaria, V; Maresca, G; Pezzoli, C; Llull, J B

    2002-03-01

    SonoVue is a new ultrasound contrast agent, which consists of stabilised microbubbles of a sulphur hexafluoride gas. The aim of the study was to assess its efficacy in the Doppler investigation of focal hepatic lesions. Seventy patients with focal liver tumours were studied. Four doses (0.3, 0.6, 1.2 and 2.4 ml) of SonoVue were administered intravenously with at least 10 min delay between each injection. A complete colour/power and spectral Doppler imaging investigation of the lesions was performed at baseline pre-dosing and after each SonoVue injection. All examinations were recorded on SVHS videotapes. Baseline and post contrast videotapes were reviewed by the on-site (un-blinded) investigators and by two off-site blinded readers (a) to grade the global quality of the Doppler scans of the focal lesions vascularity and the normal parenchymal vessels (b) to measure the duration of clinically useful Doppler signal enhancement and (c) to determine the diagnostic accuracy and performance of the enhanced versus unenhanced scans using histopathology, tumour markers, CT and/or MR as the reference standard. A statistically significant improvement was observed at all four SonoVue doses in the off site assessment of global quality of the Doppler examination of tumoral and normal parenchymal vessels in comparison with the baseline (P < 0.05). The median duration of clinically useful enhancement was significantly increased with increasing doses (P < 0.001), ranging between 1.4-2.2 min for the lowest dose and 3.2-3.8 min for the highest dose for the off-site readers. On-site assessment of diagnostic accuracy showed a significant increase in the specificity of the Doppler diagnoses (P < 0.0016) with an increase in the positive and negative predictive values and in the likelihood ratio in differentiating between benign and malignant lesions. Off-site evaluation showed a significant increase in the accuracy of enhanced Doppler diagnosis in comparison with the baseline performance

  7. Vascular color Doppler ultrasound for assessing renovascular hypertension: accuracy of the direct technique for assessing the renal arteries.

    PubMed

    Engelhorn, Carlos Alberto; Engelhorn, Ana Luiza; Pullig, Renata

    2004-05-01

    To assess the accuracy of vascular color Doppler ultrasound as compared with digital subtraction arteriography for identifying hemodynamically significant renal artery stenoses. One hundred and thirty-seven renal arteries from 69 adult patients suspected of having renovascular arterial hypertension were prospectively studied with ultrasound. The results obtained were compared in a double-blind manner with those obtained on digital subtraction arteriography, and the following parameters were calculated according to previously defined criteria: sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy. The inconclusive results (7 arteries) were excluded. The comparison of the 2 methods in regard to the 130 remaining arteries showed concordant results for 116 (89.2%) arteries and discordant results for 14 (10.8%) arteries. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of vascular color Doppler ultrasound were, respectively, 95.33%, 88.14%, 89.86%, 94.55%, and 91.94%. A good correlation between the 2 examinations was observed in the evaluation of the hemodynamically significant renal artery stenoses, making vascular color Doppler ultrasound a noninvasive method useful for selecting patients with suspected renovascular hypertension.

  8. Assessment of arterial distension based on continuous wave Doppler ultrasound with an improved Hilbert-Huang processing.

    PubMed

    Zhang, Yufeng; Su, Nafeng; Li, Zhiyao; Gou, Zhengpin; Chen, Qiuying; Zhang, Yan

    2010-01-01

    A novel approach based on continuous wave (CW) Doppler ultrasound and the Hilbert-Huang transform with end-effect restraint by mirror extending is proposed to assess arterial distension. In the approach, bidirectional Doppler signals were first separated using the phasing-filter technique from the mixed quadrature Doppler signals, which were produced by bidirectional blood and vessel wall movements. Each separated unidirectional signal was decomposed into intrinsic mode functions (IMFs) using the empirical mode decomposition with end effect restraint by mirror extending algorithm, and then the relevant IMFs that contribute to the vessel wall components were identified. Finally, the displacement waveforms of the vessel wall were calculated by integrating its moving velocity waveforms, which were extracted from the bidirectional Hilbert spectrum estimated from the identified wall IMFs. This approach was applied to simulated and clinical Doppler signals from normal common carotid arteries (CCAs). In the simulation study, the estimated wall moving velocity and displacement waveforms were compared with the theoretical ones, respectively. The mean and standard deviation of the root-mean-square errors between the estimated and theoretical wall distension of the 30 realizations was 4.2 +/- 0.4 microm. In the clinical study, peak-to-peak distension was extracted in a subject and then averaged over 15 cardiac cycles, resulting in 603 +/- 22 microm. The mean and standard deviation of the CCA distension averaged over the experimental measurements of 12 healthy subjects gave the result of 620 +/- 154 microm. The clinical results were in agreement with those measured by using the multigate Doppler ultrasound and echo tracking systems. The results show that based on the CW Doppler ultrasound, the proposed approach is practical for extracting arterial wall peak-to-peak distension correctly and could be an alternative method for the vessel wall distension estimation.

  9. A novel two-axis micromechanical scanning transducer for handheld 3D ultrasound and photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Huang, Chih-Hsien; Zou, Jun

    2016-03-01

    This paper reports the development of a new two-axis micromechanical scanning transducer for handheld 3D ultrasound imaging. It consists of a miniaturized single-element ultrasound transducer driven by a unique 2-axis liquid-immersible electromagnetic microactuator. With a mechanical scanning frequency of 19.532 Hz and an ultrasound pulse repetition rate of 5 kHz, the scanning transducer was scanned along 60 concentric paths with 256 detection points on each to simulate a physical 2D ultrasound transducer array of 60 × 256 elements. Using the scanning transducer, 3D pulse-echo ultrasound imaging of two silicon discs immersed in water as the imaging target was successfully conducted. The lateral resolution of the 3D ultrasound image was further improved with the synthetic aperture focusing technique (SAFT). The new two-axis micromechanical scanning transducer doesn't require complex and expensive multi-channel data acquisition (DAQ) electronics. Therefore, it could provide a new approach to achieve compact and low-cost 3D ultrasound and photoacoustic imaging systems, especially for handheld operations.

  10. [A 3D-ultrasound imaging system based on back-end scanning mode].

    PubMed

    Qi, Jian; Chen, Yimin; Ding, Mingyue; Wei, Chiming

    2012-07-01

    A new scanning mode is proposed that the front-end of the probe is fixed, while the back-end makes fan-shaped, scanning movement. The new scanning mode avoided ribs drawbacks successfully. Based on the new scanning mode a 3D-Ultrasound Images System is accomplished to acquire 2D data of fetusfetus fetusfetus phantom and livers and kidneys, to demonstrates the effectiveness of the new scanning mode.

  11. Three Dimensional Measurements of Boundary Layer Statistics using Scanning Doppler Lidar

    NASA Astrophysics Data System (ADS)

    Frehlich, R.

    2008-12-01

    Accurate measurements and modeling of the boundary layer is challenging, especially for the stable night time boundary layer, the highly turbulent boundary layer, and the early morning transition to convection. High quality profiles of mean and turbulent statistics of the night time boundary layer are logistically difficult using instrumented towers or instrumented research aircraft. One of the fundamental limits to the accuracy of atmospheric estimates of mean and turbulent quantities is the number of independent samples of the relevant processes. Traditional measurements from towers, sodars, radar profilers, and instrumented aircraft essentially produce a spatial sample of the atmosphere along a line defined by the mean wind (or aircraft trajectory). Advanced three dimensional measurements of the boundary layer provides the highest statistical accuracy which is essential to understand complex rapidly changing processes. The development of eye-safe scanning Doppler lidars and processing algorithms to correct for the spatial filtering by the laser pulse smoothing and the contribution from estimation error have produced profiles of the mean velocity and key turbulence statistics (the energy dissipation rate, velocity variance, and turbulence length scale) for two orthogonal horizontal velocity components. This requires accurate information about the sensing volume of the lidar measurements as well as the statistical properties of the estimation error. The various processing techniques and fundamental assumptions for the analysis of scanning Doppler lidar data will be presented for various atmospheric conditions. Unresolved issues for future work will also be outlined.

  12. PE-CMOS based C-scan ultrasound for foreign object detection in soft tissue.

    PubMed

    Liu, Chu-Chuan; Lo, Shih-Chung Ben; Freedman, Matthew T; Lasser, Marvin E; Kula, John; Sarcone, Anita; Wang, Yue

    2010-01-01

    In this paper, we introduce a C-scan ultrasound prototype and three imaging modalities for the detection of foreign objects inserted in porcine soft tissue. The object materials include bamboo, plastics, glass and aluminum alloys. The images of foreign objects were acquired using the C-scan ultrasound, a portable B-scan ultrasound, film-based radiography, and computerized radiography. The C-scan ultrasound consists of a plane wave transducer, a compound acoustic lens system, and a newly developed ultrasound sensor array based on the complementary metal-oxide semiconductor coated with piezoelectric material (PE-CMOS). The contrast-to-noise ratio (CNR) of the images were analyzed to quantitatively evaluate the detectability using different imaging modalities. The experimental results indicate that the C-scan prototype has better CNR values in 4 out of 7 objects than other modalities. Specifically, the C-scan prototype provides more detail information of the soft tissues without the speckle artifacts that are commonly seen with conventional B-scan ultrasound, and has the same orientation as the standard radiographs but without ionizing radiation.

  13. Heel Ultrasound Scan in Detecting Osteoporosis in Low Trauma Fracture Patients.

    PubMed

    Hashmi, Faiz R; Elfandi, Khaled O

    2016-06-27

    Osteoporosis is the most common metabolic disease with significant impact on the morbidity and mortality of affected patients. Osteoporosis has a significant impact on the economy worldwide. The aim of this study was to find out whether heel ultrasound is as good as central bone densitometry scanning in diagnosing osteoporosis in patients who are at high risk of osteoporosis. This was a prospective study of patients comparing heel ultrasound to central bone densitometry scanning (dual X-ray absorptiometry, DEXA) in patients. The recruited patients attended for a DEXA scan of the left hip and lumbar spine. All subjects had an ultrasound of the left heel using the quantitative heel ultrasound machine. The results of DEXA scan were blinded from the results of ultrasound and vice versa. There were 59 patients who took part in the study, 12 men and 47 women. The mean age was 66 years (SD 11.9) and mean weight was 62.5 kg (SD 10.7). The sensitivity and specificity of the ultrasound heel test to predict osteoporosis were 53% (95%CI: 29-77) and 86% (95%CI: 75-96) respectively. Specificity for predicting bone mineral density (BMD)-defined osteoporosis was high (86%), but sensitivity was low (53%). A heel ultrasound result in the osteoporotic range was highly predictive of BMD-defined osteoporosis. A positive ultrasound heel test in high risk patients is more useful in ruling in osteoporosis than a negative test to rule out osteoporosis.

  14. Use of ultrasound scanning and body condition score to evaluate composition traits in mature beef cows

    USDA-ARS?s Scientific Manuscript database

    The experiment was designed to validate the use of ultrasound to evaluate body composition in mature beef cows. Both precision and accuracy of measurement were assessed. Cull cows (n = 87) selected for highly variable fatness were used. Two experienced ultrasound technicians scanned and assigned ...

  15. Relationship between loss of echogenicity and cavitation emissions from echogenic liposomes insonified by spectral Doppler ultrasound

    NASA Astrophysics Data System (ADS)

    Radhakrishnan, Kirthi

    Cardiovascular disease is the leading cause of death and disability in the United States and worldwide. Echogenic liposomes (ELIP) are theragonistic ultrasound contrast agents (UCAs) being developed for the early detection and treatment of cardiovascular disease. Stability of the echogenicity of ELIP in physiologic conditions is crucial to their successful translation to clinical use. The stability of ELIP echogenicity was determined in vitro under physiologic conditions of total dissolved gas concentration, temperature, and hydrodynamic pressure in porcine plasma and whole blood. Ultrasound contrast agents (UCAs) have the potential to nucleate cavitation and promote both beneficial and deleterious bioeffects in vivo. Previous studies have elucidated the pressure amplitude threshold for rapid loss of echogenicity due to UCA fragmentation as a function of pulse duration and pulse repetition frequency (PRF). Previous studies have also demonstrated that UCA fragmentation was concomitant with inertial cavitation. The purpose of this study was to evaluate the relationship between stable and inertial cavitation thresholds and loss of echogenicity of ELIP as a function of pulse duration and pulse repetition frequency. Determining the relationship between cavitation thresholds and loss of echogenicity of ELIP would enable monitoring of cavitation based upon the on-screen echogenicity in clinical applications. ELIP were insonified by a clinical ultrasound scanner in duplex spectral Doppler mode at four pulse durations and four PRFs in a static fluid and in a flow system. Cavitation emissions from the UCAs insonified by Doppler pulses were recorded using a single-element passive cavitation detection (PCD) system and a passive cavitation imaging (PCI) system. Stable and inertial cavitation thresholds were ascertained. Loss of echogenicity from ELIP was assessed within regions of interest on B-mode images. Stable cavitation thresholds were found to be lower than inertial

  16. Real-time ultrasound Doppler enhances precision in image-guided approaches to the cerebello-pontine angle.

    PubMed

    Baghdasaryan, Davit; Albrecht, Marcel; Shahnazaryan, Mihr; Rosahl, Steffen

    2017-08-10

    To evaluate efficacy and reliability of intraoperative Doppler sonography in localizing the transverse and sigmoid sinuses during lateral suboccipital craniotomy. A 16-Mhz intraoperative micro-Doppler ultrasound (16Mhz, Multi-Dop pro®, Compumedics, Germany) was applied to detect the medial border of the sigmoid sinus and the inferior border of the transverse sinus in 25 patients. Micro-Doppler measurements were compared to MR- and CT-based image-guidance (Kolibri®, Brainlab, Germany). Visual detectability of the sinuses under the operating microscope was also documented. Inadvertent incision of the transverse or sigmoid sinuses did not occur in any case when the two localizing methods have been used in combination. The mean mismatch of image-guided system and micro-Doppler was 2.64mm (range 0-6mm, SD 1.55 mm). Under the microscope the transverse sinus was invisible in seven cases, the sigmoid sinus was visually undetectable in one case. The micro-Doppler indicated blood flow outside the visible borders of the sinuses in five cases. A combination of image-guidance and micro-Doppler enhances the accuracy in localizing the margins of the transverse and sigmoid sinuses in the retrosigmoid approach, thus preventing inadvertent injury. The method could potentially be applied during other craniotomies involving the exposure of a venous sinus. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Noninvasive measurement of acoustic field inside mother's uterus generated by ultrasound scanning

    NASA Astrophysics Data System (ADS)

    Antonets, V. A.; Kazakov, V. V.

    2015-07-01

    Sounds in the audible range arising in mother's uterus during conventional ultrasound scanning were recorded noninvasively for the first time. It was found that their level is comparable with the level of spoken language.

  18. Transcranial functional ultrasound imaging of the brain using microbubble-enhanced ultrasensitive Doppler

    PubMed Central

    Errico, Claudia; Osmanski, Bruno-Félix; Pezet, Sophie; Couture, Olivier; Lenkei, Zsolt; Tanter, Mickael

    2016-01-01

    Functional ultrasound (fUS) is a novel neuroimaging technique, based on high-sensitivity ultrafast Doppler imaging of cerebral blood volume, capable of measuring brain activation and connectivity in rodents with high spatiotemporal resolution (100 μm, 1 ms). However, the skull attenuates acoustic waves, so fUS in rats currently requires craniotomy or a thinned-skull window. Here we propose a non-invasive approach by enhancing the fUS signal with a contrast agent, inert gas microbubbles. Plane-wave illumination of the brain at high frame rate (500 Hz compounded sequence with three tilted plane waves, PRF = 1500Hz with a 128 element 15 MHz linear transducer), yields highly-resolved neurovascular maps. We compared fUS imaging performance through the intact skull bone (transcranial fUS) versus a thinned-skull window in the same animal. First, we show that the vascular network of the adult rat brain can be imaged transcranially only after a bolus intravenous injection of microbubbles, which leads to a 9 dB gain in the contrast-to-tissue ratio. Next, we demonstrate that functional increase in the blood volume of the primary sensory cortex after targeted electrical-evoked stimulations of the sciatic nerve is observable transcranially in presence of contrast agents, with high reproducibility (Pearson's coefficient ρ = 0.7 ± 0.1, p = 0.85). Our work demonstrates that the combination of ultrafast Doppler imaging and injection of contrast agent allows non-invasive functional brain imaging through the intact skull bone in rats. These results should ease non-invasive longitudinal studies in rodents and open a promising perspective for the adoption of highly resolved fUS approaches for the adult human brain. PMID:26416649

  19. Relationship of asymmetric dimethylarginine with penile Doppler ultrasound parameters in men with vasculogenic erectile dysfunction.

    PubMed

    Ioakeimidis, Nikolaos; Vlachopoulos, Charalambos; Rokkas, Konstantinos; Aggelis, Athanasios; Terentes-Printzios, Dimitrios; Samentzas, Alexios; Alexopoulos, Nikolaos; Stefanadis, Christodoulos

    2011-06-01

    Asymmetric dimethylarginine (ADMA), a selective endogenous nitric oxide synthase inhibitor, is elevated in many conditions associated with erectile dysfunction (ED), such as hypertension, diabetes, hyperlipidemia, and renal failure; it is also increased in men with coronary artery disease and ED. The dynamic penile colour Doppler ultrasound is considered the gold standard for the evaluation of penile vascular damage. We investigated whether the extent of ultrasonographically documented penile vascular disease is associated with higher ADMA levels. One hundred four consecutive ED patients (mean age: 56 ± 9 yr) without manifest cardiovascular/atherosclerotic disease and 31 subjects with normal erectile function matched for age and traditional risk factors were studied. We evaluated penile dynamic colour Doppler parameters of arterial insufficiency (peak systolic velocity) and veno-occlusive dysfunction (end diastolic velocity) and measured systemic inflammatory markers/mediators. Compared to men without ED, ED patients had significantly higher ADMA levels (p<0.001). ADMA was significantly increased in patients with severe arterial insufficiency (PSV<25 cm/s) compared to subjects with borderline insufficiency and men with normal penile arterial function (p<0.001, by analysis of variance). Multivariable analysis adjusting for age, mean pressure, other risk factors, high-sensitivity C-reactive protein, testosterone, and treatment showed independent inverse association between ADMA level and peak systolic velocity (p<0.01). The combination of higher ADMA level with arterial insufficiency showed greater impact on 10-yr risk of a cardiovascular event compared to either parameter alone. ADMA level is independently associated with ultrasonographically documented poor penile arterial inflow. This finding underlines the important role of ADMA as a marker of penile arterial damage and implies a contribution of this compound to the pathophysiology of generalised vascular

  20. Transcranial functional ultrasound imaging of the brain using microbubble-enhanced ultrasensitive Doppler.

    PubMed

    Errico, Claudia; Osmanski, Bruno-Félix; Pezet, Sophie; Couture, Olivier; Lenkei, Zsolt; Tanter, Mickael

    2016-01-01

    Functional ultrasound (fUS) is a novel neuroimaging technique, based on high-sensitivity ultrafast Doppler imaging of cerebral blood volume, capable of measuring brain activation and connectivity in rodents with high spatiotemporal resolution (100μm, 1ms). However, the skull attenuates acoustic waves, so fUS in rats currently requires craniotomy or a thinned-skull window. Here we propose a non-invasive approach by enhancing the fUS signal with a contrast agent, inert gas microbubbles. Plane-wave illumination of the brain at high frame rate (500Hz compounded sequence with three tilted plane waves, PRF=1500Hz with a 128 element 15MHz linear transducer), yields highly-resolved neurovascular maps. We compared fUS imaging performance through the intact skull bone (transcranial fUS) versus a thinned-skull window in the same animal. First, we show that the vascular network of the adult rat brain can be imaged transcranially only after a bolus intravenous injection of microbubbles, which leads to a 9dB gain in the contrast-to-tissue ratio. Next, we demonstrate that functional increase in the blood volume of the primary sensory cortex after targeted electrical-evoked stimulations of the sciatic nerve is observable transcranially in presence of contrast agents, with high reproducibility (Pearson's coefficient ρ=0.7±0.1, p=0.85). Our work demonstrates that the combination of ultrafast Doppler imaging and injection of contrast agent allows non-invasive functional brain imaging through the intact skull bone in rats. These results should ease non-invasive longitudinal studies in rodents and open a promising perspective for the adoption of highly resolved fUS approaches for the adult human brain. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  1. 'Son et lumière': a new combined optical and Doppler ultrasound approach to the detection of breast cancer.

    PubMed

    Watmough, D J; Moran, C; Watmough, J A

    1988-04-01

    X-ray mammography is the gold standard for diagnosis of lesions within the female breast. It is also recognized as the technique of choice for breast cancer screening in women over 50-years-old. Notwithstanding these important roles it has shortcomings in terms of limited sensitivity and specificity, especially in younger women. This paper describes the concept of a combined optical density and Doppler ultrasound method proposed initially as a supplement to mammography. A specially devised tissue compressor is also described. Results obtained using test phantoms and initial clinical studies are presented. Neovascularization at the advancing front of neoplastic lesions is believed to underlie detection of lesions by both telediaphanography and Doppler ultrasound.

  2. Doppler ultrasound velocities and resistive indexes immediately after pediatric liver transplantation: normal ranges and predictors of failure.

    PubMed

    Jamieson, Lucy H; Arys, Bo; Low, Gavin; Bhargava, Ravi; Kumbla, Surekha; Jaremko, Jacob L

    2014-07-01

    We sought to determine the ranges of Doppler ultrasound findings immediately after pediatric liver transplantation that are associated with successful outcomes or postoperative complications. This study included consecutive children who underwent Doppler ultrasound less than 48 hours after liver transplantation from 2001 to 2011. Operative reports and clinical outcome data were recorded. We had 110 patients (54% girls) with mean age at transplantation of 2.9 years (median, 1.3 years; range, 0-14 years) and a median follow-up interval of 3.5 years. Two pediatric radiologists reviewed ultrasound images in consensus. We computed descriptive statistics, interindex correlations, and analysis of variance. Twenty-four of 110 patients had a vascular complication, most commonly hepatic arterial thrombosis (seven patients). Compared with published adult normal values, normal pediatric Doppler parameters at postoperative day 1 trended toward higher normal velocities and resistive indexes (up to 0.95). Absent or low-velocity common hepatic artery flow less than 50 cm/s or a common hepatic artery resistive index less than 0.50 were significantly associated with hepatic artery thrombosis, whereas absent or low-velocity portal venous flow less than 30 cm/s or low-velocity hepatic venous flow less than 25 cm/s were significantly associated with vascular complications and a monotonic hepatic venous waveform was significantly associated with venous complications. Flow in a pediatric liver on the first day after transplantation is normally hyperdynamic, especially in the youngest transplant recipients, and, as a result, low velocities or resistive indexes are particularly concerning for complications. The pediatric-specific ranges of expected posttransplantation Doppler ultrasound findings presented in this article should assist in identifying normal variation and potentially life-threatening complications.

  3. Non-contact measurement of facial surface vibration patterns during singing by scanning laser Doppler vibrometer

    PubMed Central

    Kitamura, Tatsuya; Ohtani, Keisuke

    2015-01-01

    This paper presents a method of measuring the vibration patterns on facial surfaces by using a scanning laser Doppler vibrometer (LDV). The surfaces of the face, neck, and body vibrate during phonation and, according to Titze (2001), these vibrations occur when aerodynamic energy is efficiently converted into acoustic energy at the glottis. A vocalist's vibration velocity patterns may therefore indicate his or her phonatory status or singing skills. LDVs enable laser-based non-contact measurement of the vibration velocity and displacement of a certain point on a vibrating object, and scanning LDVs permit multipoint measurements. The benefits of scanning LDVs originate from the facts that they do not affect the vibrations of measured objects and that they can rapidly measure the vibration patterns across planes. A case study is presented herein to demonstrate the method of measuring vibration velocity patterns with a scanning LDV. The objective of the experiment was to measure the vibration velocity differences between the modal and falsetto registers while three professional soprano singers sang sustained vowels at four pitch frequencies. The results suggest that there is a possibility that pitch frequency are correlated with vibration velocity. However, further investigations are necessary to clarify the relationships between vibration velocity patterns and phonation status and singing skills. PMID:26579054

  4. Coupling airborne laser scanning and acoustic Doppler current profiler data to model stream rating curves

    NASA Astrophysics Data System (ADS)

    Lam, N.; Lyon, S. W.; Kean, J. W.

    2015-12-01

    The rating curve enables the translation of water depth into discharge through a reference cross section. Errors in estimating stream channel geometry can therefore result in increased discharge uncertainty. This study investigates coupling national-scale airborne laser scanning (ALS) and acoustic Doppler current profiler (ADCP) bathymetric survey data for generating stream rating curves. Specifically, stream channel geometries were generated from coupled ALS and ADCP scanning data collected for a well-monitored site located in northern Sweden. These data were used to define the hydraulic geometry required by a physically-based 1-D hydraulic model. The results of our study demonstrate that the effects of potential scanning data errors on the model generated rating curve were less than the uncertainties due to stream gauging measurements and empirical rating curve fitting. Further analysis of the ALS data showed that an overestimation of the streambank elevation (the main scanning data error) was primarily due to vegetation that could be adjusted for through a root-mean-square-error bias correction. We consider these findings encouraging as hydrometric agencies can potentially leverage national-scale ALS and ADCP instrumentation to reduce the cost and effort required for maintaining and establish rating curves at gauging stations.

  5. Doppler Ultrasound Detection of Preclinical Changes in Foot Arteries in Early Stage of Type 2 Diabetes

    PubMed Central

    Leoniuk, Jolanta; Łukasiewicz, Adam; Szorc, Małgorzata; Sackiewicz, Izabela; Janica, Jacek; Łebkowska, Urszula

    2014-01-01

    Summary Background There are few reports regarding the changes within the vessels in the initial stage of type 2 diabetes. The aim of this study was to estimate the hemodynamic and morphological parameters in foot arteries in type 2 diabetes subjects and to compare these parameters to those obtained in a control group of healthy volunteers. Material/Methods Ultrasound B-mode, color Doppler and pulse wave Doppler imaging of foot arteries was conducted in 37 diabetic patients and 36 non-diabetic subjects to determine their morphological (total vascular diameter and flow lumen diameter) and functional parameters (spectral analysis). Results In diabetic patients, the overall vascular diameter and wall thickness were statistically significantly larger when compared to the control group in the right dorsalis pedis artery (P=0.01; P=0.001), left dorsalis pedis artery (P=0.007; P=0.006), right posterior tibial artery (P=0.005; P=0.0005), and left posterior tibial artery (P=0.007; P=0.0002). No significant differences were observed in both groups in flow lumen diameters and blood flow parameters (PSV, EDV, PI, RI). In the diabetic group, the level of HbA1c positively correlated with flow resistance index in the right dorsalis pedis artery (r=0.38; P=0.02), right posterior tibial artery (r=0.38; P=0.02) and left posterior tibial artery (r=0.42; P=0.009). The pulsatility index within the dorsalis pedis artery decreased with increased trophic skin changes (r=–0.431, P=0.009). Conclusions In the diabetic group, overall artery diameters larger than and flow lumina comparable to the control group suggest vessel wall thickening occurring in the early stage of diabetes. Doppler flow parameters are comparable in both groups. In the diabetic group, the level of HbA1c positively correlated with flow resistance index and negative correlation was observed between the intensity of trophic skin changes and the pulsatility index. PMID:25202434

  6. Color Doppler ultrasound and gamma imaging of intratumorally injected 500 nm iron-silica nanoshells.

    PubMed

    Liberman, Alexander; Wu, Zhe; Barback, Christopher V; Viveros, Robert; Blair, Sarah L; Ellies, Lesley G; Vera, David R; Mattrey, Robert F; Kummel, Andrew C; Trogler, William C

    2013-07-23

    Perfluoropentane gas filled iron-silica nanoshells have been developed as stationary ultrasound contrast agents for marking tumors to guide surgical resection. It is critical to establish their long-term imaging efficacy, as well as biodistribution. This work shows that 500 nm Fe-SiO2 nanoshells can be imaged by color Doppler ultrasound over the course of 10 days in Py8119 tumor bearing mice. The 500 nm nonbiodegradable SiO2 and biodegradable Fe-SiO2 nanoshells were functionalized with diethylenetriamine pentaacetic acid (DTPA) ligand and radiolabeled with (111)In(3+) for biodistribution studies in nu/nu mice. The majority of radioactivity was detected in the liver and kidneys following intravenous (IV) administration of nanoshells to healthy animals. By contrast, after nanoshells were injected intratumorally, most of the radioactivity remained at the injection site; however, some nanoshells escaped into circulation and were distributed similarly as those given intravenously. For intratumoral delivery of nanoshells and IV delivery to healthy animals, little difference was seen between the biodistribution of SiO2 and biodegradable Fe-SiO2 nanoshells. However, when nanoshells were administered IV to tumor bearing mice, a significant increase was observed in liver accumulation of SiO2 nanoshells relative to biodegradable Fe-SiO2 nanoshells. Both SiO2 and Fe-SiO2 nanoshells accumulate passively in proportion to tumor mass, during intravenous delivery of nanoshells. This is the first report of the biodistribution following intratumoral injection of any biodegradable silica particle, as well as the first report demonstrating the utility of DTPA-(111)In labeling for studying silica nanoparticle biodistributions.

  7. Personalized peer-comparison feedback and its effect on emergency medicine resident ultrasound scan numbers.

    PubMed

    Hempel, Dorothea; Pivetta, Emanuele; Kimberly, Heidi H

    2014-01-14

    Clinician-performed ultrasound has become a widely utilized tool in emergency medicine and is a mandatory component of the residency curricula. We aimed to assess the effect of personalized peer-comparison feedback on the number of ultrasound scans performed by emergency medicine residents. A personalized peer-comparison feedback was performed by sending 44 emergency medicine residents a document including personally identified scan numbers and class averages. The number of ultrasound scans per clinical shift for a 3-month period before and after the feedback intervention was calculated. The average number of ultrasound exams per shift improved from 0.39 scans/shift before to 0.61 scans/shift after feedback (p = 0.04). Among the second year residents, the scans/shift ratio improved from 0.35 to 0.87 (p = 0.07); for third year residents, from 0.51 to 0.58 (p = 0.46); and from 0.33 to 0.41 (p = 0.21) for the fourth year residents before and after the intervention, respectively. A personalized peer-comparison feedback provided to emergency medicine residents resulted in increased ultrasound scan numbers per clinical shift. Incorporating this method of feedback may help encourage residents to scan more frequently.

  8. Direct comparison of high-temporal-resolution CINE MRI with Doppler ultrasound for assessment of diastolic dysfunction in mice.

    PubMed

    Roberts, Thomas A; Price, Anthony N; Jackson, Laurence H; Taylor, Valerie; David, Anna L; Lythgoe, Mark F; Stuckey, Daniel J

    2017-10-01

    Diastolic dysfunction is a sensitive early indicator of heart failure and can provide additional data to conventional measures of systolic function. Transmitral Doppler ultrasound, which measures the one-dimensional flow of blood through the mitral valve, is currently the preferred method for the measurement of diastolic function, but the measurement of the left ventricular volume changes using high-temporal-resolution cinematic magnetic resonance imaging (CINE MRI) is an alternative approach which is emerging as a potentially more robust and user-independent technique. Here, we investigated the performance of high-temporal-resolution CINE MRI and compared it with ultrasound for the detection of diastolic dysfunction in a mouse model of myocardial infarction. An in-house, high-temporal-resolution, retrospectively gated CINE sequence was developed with a temporal resolution of 1 ms. Diastolic function in mice was assessed using a custom-made, open-source reconstruction package. Early (E) and late (A) left ventricular filling phases were easily identifiable, and these measurements were compared directly with high-frequency, pulsed-wave, Doppler ultrasound measurements of mitral valve inflow. A repeatability study established that high-temporal-resolution CINE MRI and Doppler ultrasound showed comparable accuracy when measuring E/A in normal control mice. However, when applied in a mouse model of myocardial infarction, high-temporal-resolution CINE MRI indicated diastolic heart failure (E/A = 0.94 ± 0.11), whereas ultrasound falsely detected normal cardiac function (E/A = 1.21 ± 0.11). The addition of high-temporal-resolution CINE MRI to preclinical imaging studies enhances the library of sequences available to cardiac researchers and potentially identifies diastolic heart failure early in disease progression. © 2017 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.

  9. Velocity profiles inside volcanic clouds from three-dimensional scanning microwave dual-polarization Doppler radars

    NASA Astrophysics Data System (ADS)

    Montopoli, Mario

    2016-07-01

    In this work, velocity profiles within a volcanic tephra cloud obtained by dual-polarization Doppler radar acquisitions with three-dimensional (3-D) mechanical scanning capability are analyzed. A method for segmenting the radar volumes into three velocity regimes: vertical updraft, vertical fallout, and horizontal wind advection within a volcanic tephra cloud using dual-polarization Doppler radar moments is proposed. The horizontal and vertical velocity components within the regimes are retrieved using a novel procedure that makes assumptions concerning the characteristics of the winds inside these regimes. The vertical velocities retrieved are combined with 1-D simulations to derive additional parameters including particle fallout, mass flux, and particle sizes. The explosive event occurred on 23 November 2013 at the Mount Etna volcano (Sicily, Italy), is considered a demonstrative case in which to analyze the radar Doppler signal inside the tephra column. The X-band radar (3 cm wavelength) in the Catania, Italy, airport observed the 3-D scenes of the Etna tephra cloud ~32 km from the volcano vent every 10 min. From the radar-derived vertical velocity profiles of updraft, particle fallout, and horizontal transportation, an exit velocity of 150 m/s, mass flux rate of 1.37 • 107 kg/s, particle fallout velocity of 18 m/s, and diameters of precipitating tephra particles equal to 0.8 cm are estimated on average. These numbers are shown to be consistent with theoretical 1-D simulations of plume dynamics and local reports at the ground, respectively. A thickness of 3 ± 0.36 km for the downwind ash cloud is also inferred by differentiating the radar-derived cloud top and the height of transition between the convective and buoyancy regions, the latter being inferred by the estimated vertical updraft velocity profile. The unique nature of the case study as well as the novelty of the segmentation and retrieval methods presented potentially give new insights into the

  10. Effect of low level laser therapy on revascularization of free gingival graft using ultrasound Doppler flowmetry

    PubMed Central

    Arunachalam, Lalitha T.; Sudhakar, Uma; Janarthanam, Akila Sivaranjani; Das, Nimisha Mithra

    2014-01-01

    Low level laser therapy (LLLT) is widely used during the post-operative period to accelerate the healing process. It promotes beneficial biological action on neovascularization with anti-inflammatory and analgesic effects. Two systemically healthy patients with Miller's grade II recession on 33 and 41, respectively, were treated with free gingival graft. After surgery, second patient received LLLT using a 830 nm diode laser, with output power of 0.1 W on the first day half hour following surgery, on the third day, seventh day, and lastly on the ninth day. Both the patients were asked to assess the pain on second, fourth and tenth day using a Numerical Rating Scale and revascularization of the grafted area was assessed using a color Doppler ultrasound imaging on the fourth and the ninth day. Neovascularization was noted in both the patients but the second patient elicited marked increase in vascularity on the fourth as well as the tenth day and drastic reduction in pain on day four, with no change on the tenth day. The results showed that LLLT was an effective adjunctive treatment in promoting reevascularization and pain control during early healing of free gingival graft. PMID:25024560

  11. Transcranial Doppler ultrasound and the etiology of neurologic decompression sickness during altitude decompression

    NASA Technical Reports Server (NTRS)

    Norfleet, W. T.; Powell, M. R.; Kumar, K. Vasantha; Waligora, J.

    1993-01-01

    The presence of gas bubbles in the arterial circulation can occur from iatrogenic mishaps, cardiopulmonary bypass devices, or following decompression, e.g., in deep-sea or SCUBA diving or in astronauts during extravehicular activities (EVA). We have examined the pathophysiology of neurological decompression sickness in human subjects who developed a large number of small gas bubbles in the right side of the heart as a result of hypobaric exposures. In one case, gas bubbles were detected in the middle cerebral artery (MCA) and the subject developed neurological symptoms; a 'resting' patent foramen ovalae (PFO) was found upon saline contrast echocardiography. A PFO was also detected in another individual who developed Spencer Grade 4 precordial Doppler ultrasound bubbles, but no evidence was seen of arterialization of bubbles upon insonation of either the MCA or common carotid artery. The reason for this difference in the behavior of intracardiac bubbles in these two individuals is not known. To date, we have not found evidence of right-to-left shunting of bubbles through pulmonary vasculature. The volume of gas bubbles present following decompression is examined and compared with the number arising from saline contrast injection. The estimates are comparable.

  12. Utility of transcranial Doppler ultrasound for the integrative assessment of cerebrovascular function.

    PubMed

    Willie, C K; Colino, F L; Bailey, D M; Tzeng, Y C; Binsted, G; Jones, L W; Haykowsky, M J; Bellapart, J; Ogoh, S; Smith, K J; Smirl, J D; Day, T A; Lucas, S J; Eller, L K; Ainslie, P N

    2011-03-30

    There is considerable utility in the use of transcranial Doppler ultrasound (TCD) to assess cerebrovascular function. The brain is unique in its high energy and oxygen demand but limited capacity for energy storage that necessitates an effective means of regional blood delivery. The relative low cost, ease-of-use, non-invasiveness, and excellent temporal resolution of TCD make it an ideal tool for the examination of cerebrovascular function in both research and clinical settings. TCD is an efficient tool to access blood velocities within the cerebral vessels, cerebral autoregulation, cerebrovascular reactivity to CO(2), and neurovascular coupling, in both physiological states and in pathological conditions such as stroke and head trauma. In this review, we provide: (1) an overview of TCD methodology with respect to other techniques; (2) a methodological synopsis of the cerebrovascular exam using TCD; (3) an overview of the physiological mechanisms involved in regulation of the cerebral blood flow; (4) the utility of TCD for assessment of cerebrovascular pathology; and (5) recommendations for the assessment of four critical and complimentary aspects of cerebrovascular function: intra-cranial blood flow velocity, cerebral autoregulation, cerebral reactivity, and neurovascular coupling. The integration of these regulatory mechanisms from an integrated systems perspective is discussed, and future research directions are explored.

  13. Clinical value of color doppler ultrasound in prenatal diagnosis of umbilical cord entry abnormity

    PubMed Central

    Sun, Jiandong; Wang, Li; Li, Yinghui

    2016-01-01

    Objective: To study the clinical value of prenatal diagnosis of umbilical cord entry abnormity (UCEA) by means of color Doppler ultrasound (CDUS). Methods: Clinical data of sixty-four cases with confirmed umbilical cord entry abnormity were reviewed and the specific UCEA conditions and the outcomes of perinatal infants were analyzed. Results: Detection rates of marginal umbilical cord entry abnormity and velamentous umbilical cord entry abnormity by means of CDUS at second trimester were 94.1% and 93.8% respecdtively much higher than 80.0% and 68.8% which were those of third trimester. Discrepancy had statistical significance (P<0.05). True positive rate of prenatal diagnosis of UCEA by means of CDUS was 85.9% (55/64), and false negative rate was 14.1% (9/64). Among sixty four patients with UCEA, seventeen patients (26.6%) underwent selective caesarean delivery; twenty-six patients (35.9%) underwent emergency caesarean delivery and twenty-four patients (37.5%) had normal delivery. Conclusion: Prenatal diagnosis of UCEA by means of CDUS is intuitive and accurate. It provides an evidence for determination of the best time to diagnose UCEA, and also offers a proper advice for pregnant women about delivery mode to ensure the fetus survival rate, which is clinically valuable. PMID:28083036

  14. Estimation of the viscoelastic properties of vessel walls using a computational model and Doppler ultrasound

    NASA Astrophysics Data System (ADS)

    Balocco, Simone; Basset, Olivier; Courbebaisse, Guy; Boni, Enrico; Frangi, Alejandro F.; Tortoli, Piero; Cachard, Christian

    2010-06-01

    Human arteries affected by atherosclerosis are characterized by altered wall viscoelastic properties. The possibility of noninvasively assessing arterial viscoelasticity in vivo would significantly contribute to the early diagnosis and prevention of this disease. This paper presents a noniterative technique to estimate the viscoelastic parameters of a vascular wall Zener model. The approach requires the simultaneous measurement of flow variations and wall displacements, which can be provided by suitable ultrasound Doppler instruments. Viscoelastic parameters are estimated by fitting the theoretical constitutive equations to the experimental measurements using an ARMA parameter approach. The accuracy and sensitivity of the proposed method are tested using reference data generated by numerical simulations of arterial pulsation in which the physiological conditions and the viscoelastic parameters of the model can be suitably varied. The estimated values quantitatively agree with the reference values, showing that the only parameter affected by changing the physiological conditions is viscosity, whose relative error was about 27% even when a poor signal-to-noise ratio is simulated. Finally, the feasibility of the method is illustrated through three measurements made at different flow regimes on a cylindrical vessel phantom, yielding a parameter mean estimation error of 25%.

  15. Estimation of the viscoelastic properties of vessel walls using a computational model and Doppler ultrasound.

    PubMed

    Balocco, Simone; Basset, Olivier; Courbebaisse, Guy; Boni, Enrico; Frangi, Alejandro F; Tortoli, Piero; Cachard, Christian

    2010-06-21

    Human arteries affected by atherosclerosis are characterized by altered wall viscoelastic properties. The possibility of noninvasively assessing arterial viscoelasticity in vivo would significantly contribute to the early diagnosis and prevention of this disease. This paper presents a noniterative technique to estimate the viscoelastic parameters of a vascular wall Zener model. The approach requires the simultaneous measurement of flow variations and wall displacements, which can be provided by suitable ultrasound Doppler instruments. Viscoelastic parameters are estimated by fitting the theoretical constitutive equations to the experimental measurements using an ARMA parameter approach. The accuracy and sensitivity of the proposed method are tested using reference data generated by numerical simulations of arterial pulsation in which the physiological conditions and the viscoelastic parameters of the model can be suitably varied. The estimated values quantitatively agree with the reference values, showing that the only parameter affected by changing the physiological conditions is viscosity, whose relative error was about 27% even when a poor signal-to-noise ratio is simulated. Finally, the feasibility of the method is illustrated through three measurements made at different flow regimes on a cylindrical vessel phantom, yielding a parameter mean estimation error of 25%.

  16. Improved determination of vascular blood-flow shear rate using Doppler ultrasound

    NASA Astrophysics Data System (ADS)

    Farison, James B.; Begeman, Garett A.; Salles-Cunha, Sergio X.; Beebe, Hugh G.

    1997-05-01

    Shear rate has been linked to endothelial and smooth muscle cell function, neointimal hyperplasia, poststenotic dilation and progression of atherosclerotic plaque. In vivo studies of shear rate have been limited in humans due to the lack of a truly accurate noninvasive method of measuring blood flow. In clinical vascular laboratories, the primary method of wall shear rate estimation is the scaled ratio between the center line systolic velocity and the local arterial radius. The present study compares this method with the shear rate calculated directly from data collected using a Doppler ultrasound scanner. Blood flow in the superficial femoral artery of 20 subjects was measured during three stages of distal resistance. Analysis and display programs were written for use with the MATLAB image processing software package. The experimental values of shear rate were calculated using the formal definition and then compared to the standard estimate. In all three states of distal resistance, the experimental values were significantly higher than the estimated values by a factor of approximately 1.57. These results led to the conclusion that the direct method of measuring shear rate is more precise and should replace the estimation model in the clinical laboratory.

  17. Carotid duplex ultrasound and transcranial Doppler findings in commercial divers and pilots.

    PubMed

    Dormanesh, Banafshe; Vosoughi, Kia; Akhoundi, Fahimeh H; Mehrpour, Masoud; Fereshtehnejad, Seyed-Mohammad; Esmaeili, Setareh; Sabet, Azin Shafiee

    2016-12-01

    The risky working environments of divers and pilots, and the possible role of extreme ambient pressure in carotid stenosis, make ischemic stroke an important occupational concern among these professionals. In this study, we aimed to evaluate the association of being exposed to hyperbaric or hypobaric conditions with carotid artery stenosis by comparing common carotid intima-media thickness (CCIMT) and blood flow velocities of cerebral arteries in divers and pilots using carotid duplex ultrasound (CDUS) and transcranial Doppler (TCD). CDUS and transtemporal TCD were performed in 29 divers, 36 pilots and 30 control participants. Medical history, blood pressure, lipid profile and blood sugar were recorded to control the previously well-known risk factors of atherosclerosis. Findings of the CDUS and TCD [including: CCIMT and blood flow velocities of internal carotid artery (ICA), common carotid artery (CCA), and middle cerebral artery (MCA)] of divers and pilots were compared with those of the control group using regression analysis models. Both right and left side CCIMT were significantly higher in divers (P < 0.05) and pilots (P < 0.05) in comparison with the control group. Carotid index [peak systolic velocity (PSV) of ICA/PSV of CCA) of divers and pilots were also higher than the control group. TCD findings were not significantly different between divers, pilots, and the control group. Increased CCIMT and carotid index in diver and pilot groups appear to be suggestive of accelerated atherosclerosis of carotid artery in these occupational groups.

  18. Doppler ultrasound measurement of resistance index in the diagnosis of prostate cancer.

    PubMed

    Huang, Wei; Cen, Son; Kang, Xin-Li; Wang, Wei Fu; Wang, Yang; Chen, Xiang

    2015-01-01

    Prostate cancer (PCa) remains the second leading cause of cancer diagnosis worldwide. Early diagnosis and treatment of PCa is critical since the long-term prognosis is excellent in patients with tumors confined to the prostate gland. The current meta-analysis investigates the diagnostic value of resistive index (RI) measurement using color Doppler ultrasound in patients with PCa. Electronic literature databases were exhaustively searched for relevant studies published prior to May 31, 2014. Nine studies met our predetermined inclusion criteria for the present meta-analysis. The methodologic quality of the selected studies was independently assessed by 2 reviewers based on Quality Assessment of Diagnostic Accuracy Studies tool. Our meta-analysis results showed that RI values were significantly higher in malignant prostate tissues compared to normal prostate tissues (standardized mean difference [SMD] 0.42, 95% confidence interval [CI] 0.12~0.73, p = 0.007) and benign prostate tissues (SMD 0.41, 95% CI 0.26~0.56, p<0.001). Subgroup analysis based on the diagnostic instruments used revealed that RI values were accurate in diagnosis of PCa when compared between malignant tissue vs normal tissue and malignant tissue vs benign tissue (all p<0.05). Taken together, our findings support the potential clinical applications of RI values in diagnosis of PCa.

  19. Scalpel versus electrosurgery: Comparison of gingival perfusion status using ultrasound Doppler flowmetry

    PubMed Central

    Manivannan, N.; Ahathya, R. S.; Rajaram, P. C.

    2013-01-01

    The main prerequisites of any surgical procedure are achievement of good visibility and access to the site with minimal bleeding and rapid and painless healing. With the advancement of technology the armamentarium for oral surgical procedures has also widened. The use of alternate methods to the traditional scalpel such as electrosurgery, laser, and chemicals has been widely experimented with. This article aims to report the gingival perfusion pre-operatively and post-operatively, comparing the use of scalpel and electrosurgery in different anatomic sites in patient. Since wound healing is influenced by its revascularization rate, which follows the pattern of new connective tissue formation, the perfusion status of the gingiva has been studied using ultrasound spectral Doppler. The results of our study show that there was 30% more blood flow by 7th day, 19% more blood flow by 15th day and 11% more blood flow by 30th day in sites where the scalpel was used compared with sites where electrosurgery technique was used. PMID:23956596

  20. Does pre- and post-angioplasty Doppler ultrasound evaluation help in predicting vascular access outcome?

    PubMed

    Guedes-Marques, Maria; Maia, Pedro A; Neves, Fernando; Ferreira, Aníbal; Cruz, João; Carvalho, Dulce; Oliveira, Carlos; Barreto, Carlos; Carvalho, Telmo; Ponce, Pedro

    2016-11-02

    Kidney Disease - Improving Global Outcomes (KDIGO) recommends post-percutaneous transluminal angioplasty (PTA) <30% residual stenosis (RS) and hemodynamic parameters improvement. Primary end point: how post-PTA access blood flow (ABF) improvement predicts vascular access (VA) outcome. Secondary: compare Doppler ultrasound (DU) and angiography diagnostic accuracy; determine how other factors predict outcome. Eighty patients. DU evaluation performed pre- and post-PTA. Several parameters recorded. Secondary patency verified after 6 months. Initial ABF 537 ± 248 mL/min; final ABF 1013 ± 354 mL/min. Number and location of stenosis was highly correlated between DU and angiography (p<0.001); central vessels mismatching. First semester overall survival was 63%; significantly better for fistulas (76%) than grafts (51.7%), p 0.044. Final RS>30% associated to better survival, p 0.038. Initial ABF<500 mL/min and multiple stenosis did not affect outcome (p>0.05). A >2-fold ABF increase had no significant impact on fistulas (p>0.05) but was significantly associated with worst outcomes in grafts (23.1% vs. 73.5%, p 0.009). Grafts had lower survival (HR 3.3, p 0.034). Although less accurate for central lesions, DU has a key role on VA surveillance, allowing a morphologic and hemodynamic assessment. Angioplasty is effective in preserving VA; however, it may increase restenosis due to accelerated neointimal hyperplasia. Current parameters are not useful. Trials addressing this issue are needed.

  1. Pulsatility Produced by the Hemodialysis Roller Pump as Measured by Doppler Ultrasound.

    PubMed

    Fulker, David; Keshavarzi, Gholamreza; Simmons, Anne; Pugh, Debbie; Barber, Tracie

    2015-11-01

    Microbubbles have previously been detected in the hemodialysis extracorporeal circuit and can enter the blood vessel leading to potential complications. A potential source of these microbubbles is highly pulsatile flow resulting in cavitation. This study quantified the pulsatility produced by the roller pump throughout the extracorporeal circuit. A Sonosite S-series ultrasound probe (FUJIFILM Sonosite Inc., Tokyo, Japan) was used on a single patient during normal hemodialysis treatment. The Doppler waveform showed highly pulsatile flow throughout the circuit with the greatest pulse occurring after the pump itself. The velocity pulse after the pump ranged from 57.6 ± 1.74 cm/s to -72 ± 4.13 cm/s. Flow reversal occurred when contact between the forward roller and tubing ended. The amplitude of the pulse was reduced from 129.6 cm/s to 16.25 cm/s and 6.87 cm/s following the dialyzer and venous air trap. This resulted in almost nonpulsatile, continuous flow returning to the patient through the venous needle. These results indicate that the roller pump may be a source of microbubble formation from cavitation due to the highly pulsatile blood flow. The venous air trap was identified as the most effective mechanism in reducing the pulsatility. The inclusion of multiple rollers is also recommended to offer an effective solution in dampening the pulse produced by the pump.

  2. Electrostatic forward-viewing scanning probe for Doppler optical coherence tomography using a dissipative polymer catheter.

    PubMed

    Munce, Nigel R; Mariampillai, Adrian; Standish, Beau A; Pop, Mihaela; Anderson, Kevan J; Liu, George Y; Luk, Tim; Courtney, Brian K; Wright, Graham A; Vitkin, I Alex; Yang, Victor X D

    2008-04-01

    A novel flexible scanning optical probe is constructed with a finely etched optical fiber strung through a platinum coil in the lumen of a dissipative polymer. The packaged probe is 2.2 mm in diameter with a rigid length of 6mm when using a ball lens or 12 mm when scanning the fiber proximal to a gradient-index (GRIN) lens. Driven by constant high voltage (1-3 kV) at low current (< 5 microA), the probe oscillates to provide wide forward-viewing angle (13 degrees and 33 degrees with ball and GRIN lens designs, respectively) and high-frame-rate (10-140 fps) operation. Motion of the probe tip is observed with a high-speed camera and compared with theory. Optical coherence tomography (OCT) imaging with the probe is demonstrated with a wavelength-swept source laser. Images of an IR card as well as in vivo Doppler OCT images of a tadpole heart are presented. This optomechanical design offers a simple, inexpensive method to obtain a high-frame-rate forward-viewing scanning probe.

  3. Chest wall segmentation in automated 3D breast ultrasound scans.

    PubMed

    Tan, Tao; Platel, Bram; Mann, Ritse M; Huisman, Henkjan; Karssemeijer, Nico

    2013-12-01

    In this paper, we present an automatic method to segment the chest wall in automated 3D breast ultrasound images. Determining the location of the chest wall in automated 3D breast ultrasound images is necessary in computer-aided detection systems to remove automatically detected cancer candidates beyond the chest wall and it can be of great help for inter- and intra-modal image registration. We show that the visible part of the chest wall in an automated 3D breast ultrasound image can be accurately modeled by a cylinder. We fit the surface of our cylinder model to a set of automatically detected rib-surface points. The detection of the rib-surface points is done by a classifier using features representing local image intensity patterns and presence of rib shadows. Due to attenuation of the ultrasound signal, a clear shadow is visible behind the ribs. Evaluation of our segmentation method is done by computing the distance of manually annotated rib points to the surface of the automatically detected chest wall. We examined the performance on images obtained with the two most common 3D breast ultrasound devices in the market. In a dataset of 142 images, the average mean distance of the annotated points to the segmented chest wall was 5.59 ± 3.08 mm. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Vibration measurements using continuous scanning laser Doppler vibrometry: theoretical velocity sensitivity analysis with applications

    NASA Astrophysics Data System (ADS)

    Halkon, B. J.; Rothberg, S. J.

    2003-03-01

    It is readily accepted that a laser vibrometer measures target velocity in the direction of the incident laser beam, but this measured velocity must be considered in terms of the various components of the target velocity. This paper begins with a review of the theoretical description of the velocity sensed by a single laser beam incident in an arbitrary direction on a rotating target undergoing arbitrary vibration. The measured velocity is presented as the sum of six terms, each the product of a combination of geometric parameters, relating to the laser beam orientation, and a combination of motion parameters - the 'vibration sets'. This totally general velocity sensitivity model can be applied to any measurement configuration on any target. The model is also sufficiently versatile to incorporate time-dependent beam orientation and this is described in this paper, with reference to continuous scanning laser Doppler vibrometry. For continuous scanning applications, the velocity sensitivity model is shown formulated in two useful ways. The first is in terms of the laser beam orientation angles, developing the original model to include time dependency in the angles, whilst the second is an entirely new development in which the model is written in terms of the mirror scan angles, since it is these which the operator would seek to control in practice. In the original derivation, the illuminated section of the rotating target was assumed to be of rigid cross section but, since continuous scanning measurements are employed on targets with flexible cross sections, such as beams, panels and thin or bladed discs, the theory is developed in this paper for the first time to include provision for such flexibility.

  5. Viewing ultrasound scan images prior to termination of pregnancy: choice for women or conflict for ultrasonographers?

    PubMed

    Graham, O; Ankrett, S; Killick, S R

    2010-01-01

    Establishing pregnancy location is key to minimising the risks of abortion, and establishing gestational age optimises women's choice of procedure and timing. There is limited information in UK practice about the views of women having an ultrasound before an abortion with regards to whether they would wish to see the scan image of their fetus. We therefore surveyed the views of women having pre-abortion ultrasound scans and the views of ultrasonographers, using self-completed anonymous questionnaires. Responses were available for analysis from 191 women aged 16 to over 45. A total of 25 (13%) women had seen their scan. Of those who did not see their scan, 40 (24%) said they would have liked to see it, to aid their decision-making, as a right, or out of curiosity. Nine out of 17 ultrasonographers completed their questionnaires. Four ultrasonographers thought that women having scans before an abortion should see their scan images if they wished and another four thought they should not because of possible psychological effects. Their response also highlighted possible effects of such scans on those performing them. Given the choice, a larger number of women would like to see their scan images than actually ask. Women request to see their pre-abortion ultrasound images for their own individual reasons, which should be respected. Ultrasonographers may have conflict or ethical dilemmas when performing pre-abortion scans and they should be supported in identifying women for whom looking at their scan images would be of benefit.

  6. Microwave thermal imaging of scanned focused ultrasound heating: animal experiments

    NASA Astrophysics Data System (ADS)

    Zhou, Tian; Meaney, Paul M.; Hoopes, P. Jack; Geimer, Shireen D.; Paulsen, Keith D.

    2011-03-01

    High intensity focused ultrasound (HIFU) uses focused ultrasound beams to ablate localized tumors noninvasively. Multiple clinical trials using HIFU treatment of liver, kidney, breast, pancreas and brain tumors have been conducted, while monitoring the temperature distribution with various imaging modalities such as MRI, CT and ultrasound. HIFU has achieved only minimal acceptance partially due to insufficient guidance from the limited temperature monitoring capability and availability. MR proton resonance frequency (PRF) shift thermometry is currently the most effective monitoring method; however, it is insensitive in temperature changes in fat, susceptible to motion artifacts, and is high cost. Exploiting the relationship between dielectric properties (i.e. permittivity and conductivity) and tissue temperature, in vivo dielectric property distributions of tissue during heating were reconstructed with our microwave tomographic imaging technology. Previous phantom studies have demonstrated sub-Celsius temperature accuracy and sub-centimeter spatial resolution in microwave thermal imaging. In this paper, initial animal experiments have been conducted to further investigate its potential. In vivo conductivity changes inside the piglet's liver due to focused ultrasound heating were observed in the microwave images with good correlation between conductivity changes and temperature.

  7. Anticoagulant therapy for venous thromboembolism detected by Doppler ultrasound in patients with metastatic colorectal cancer receiving bevacizumab

    PubMed Central

    Suenaga, Mitsukuni; Mizunuma, Nobuyuki; Shinozaki, Eiji; Matsusaka, Satoshi; Ozaka, Masato; Ogura, Mariko; Chin, Keisho; Yamaguchi, Toshiharu

    2015-01-01

    Background Doppler ultrasound imaging is useful for management of venous thromboembolism associated with a subclavicular implantable central venous access system in patients receiving bevacizumab (Bev). We investigated the efficacy and safety of our anticoagulant regimen based on Doppler findings. Methods Patients aged ≤75 years with metastatic colorectal cancer, no history of thromboembolism, and no prior use of Bev received chemotherapy plus Bev. Doppler ultrasound imaging of the deep venous system to detect thrombosis was performed after the first course of Bev and repeated after the third course in patients with asymptomatic thrombosis. Indications for anticoagulant therapy in patients with asymptomatic thrombosis were as follows: enlarging thrombus (E), thrombus >40 mm in diameter (S), thrombus involving the superior vena cava (C), and decreased blood flow (V). Results Among 79 patients enrolled in this study, asymptomatic thrombosis was detected in 56 patients (70.9%) by Doppler ultrasound imaging after the first course of Bev and there was no thrombus in 23 patients (29.1%). Of these 56 patients, 11 (19.6%) received anticoagulant therapy with warfarin, including eight after the first course and three after follow-up imaging. S + V was observed in four of 11 patients (36.4%), as well as V in two (18.2%), S + V + C in one (9.1%), E + S + V in one (9.1%), E + C in one (9.1%), E in one (9.1%), and C in one (9.1%). All patients resumed chemotherapy, including seven who resumed Bev. Improvement or stabilization of thrombi was achieved in ten patients (90.9%). Only one patient had symptomatic thromboembolism. Mild bleeding due to anticoagulant therapy occurred in six patients (54.5%), but there were no treatment-related severe adverse events or deaths. Severe thromboembolism was not observed in the other 68 patients. Conclusion Our anticoagulant protocol for asymptomatic thrombosis detected by Doppler ultrasound imaging was effective at preventing severe

  8. Assessment of cerebral lateralization in children using functional transcranial Doppler ultrasound (fTCD).

    PubMed

    Bishop, Dorothy V M; Badcock, Nicholas A; Holt, Georgina

    2010-09-27

    There are many unanswered questions about cerebral lateralization. In particular, it remains unclear which aspects of language and nonverbal ability are lateralized, whether there are any disadvantages associated with atypical patterns of cerebral lateralization, and whether cerebral lateralization develops with age. In the past, researchers interested in these questions tended to use handedness as a proxy measure for cerebral lateralization, but this is unsatisfactory because handedness is only a weak and indirect indicator of laterality of cognitive functions. Other methods, such as fMRI, are expensive for large-scale studies, and not always feasible with children. Here we will describe the use of functional transcranial Doppler ultrasound (fTCD) as a cost-effective, non-invasive and reliable method for assessing cerebral lateralization. The procedure involves measuring blood flow in the middle cerebral artery via an ultrasound probe placed just in front of the ear. Our work builds on work by Rune Aaslid, who co-introduced TCD in 1982, and Stefan Knecht, Michael Deppe and their colleagues at the University of Münster, who pioneered the use of simultaneous measurements of left- and right middle cerebral artery blood flow, and devised a method of correcting for heart beat activity. This made it possible to see a clear increase in left-sided blood flow during language generation, with lateralization agreeing well with that obtained using other methods. The middle cerebral artery has a very wide vascular territory (see Figure 1) and the method does not provide useful information about localization within a hemisphere. Our experience suggests it is particularly sensitive to tasks that involve explicit or implicit speech production. The 'gold standard' task is a word generation task (e.g. think of as many words as you can that begin with the letter 'B'), but this is not suitable for young children and others with limited literacy skills. Compared with other brain

  9. Exploiting Continuous Scanning Laser Doppler Vibrometry in timing belt dynamic characterisation

    NASA Astrophysics Data System (ADS)

    Chiariotti, P.; Martarelli, M.; Castellini, P.

    2017-03-01

    Dynamic behaviour of timing belts has always interested the engineering community over the years. Nowadays, there are several numerical methods to predict the dynamics of these systems. However, the tuning of such models by experimental approaches still represents an issue: an accurate characterisation does require a measurement in operating conditions since the belt mounting condition might severely affect its dynamic behaviour. Moreover, since the belt is constantly moving during running conditions, non-contact measurement methods are needed. Laser Doppler Vibrometry (LDV) and imaging techniques do represent valid candidates for this purpose. This paper aims at describing the use of Continuous Scanning LDV (CSLDV) as a tool for the dynamic characterisation of timing belts in IC (Internal Combustion) engines (cylinder head). The high-spatial resolution data that can be collected in short testing time makes CSLDV highly suitable for such application. The measurement on a moving surface, however, represents a challenge for CSLDV. The paper discusses how the belt in-plane speed influences CSLDV signal and how an order-based multi-harmonic excitation might affect the recovery of Operational Deflection Shapes in a CSLDV test. A comparison with a standard Discrete Scanning LDV measurement is also given in order to show that a CSLDV test, if well designed, can indeed provide the same amount of information in a drastically reduced amount of time.

  10. Accurate estimation of normal incidence absorption coefficients with confidence intervals using a scanning laser Doppler vibrometer

    NASA Astrophysics Data System (ADS)

    Vuye, Cedric; Vanlanduit, Steve; Guillaume, Patrick

    2009-06-01

    When using optical measurements of the sound fields inside a glass tube, near the material under test, to estimate the reflection and absorption coefficients, not only these acoustical parameters but also confidence intervals can be determined. The sound fields are visualized using a scanning laser Doppler vibrometer (SLDV). In this paper the influence of different test signals on the quality of the results, obtained with this technique, is examined. The amount of data gathered during one measurement scan makes a thorough statistical analysis possible leading to the knowledge of confidence intervals. The use of a multi-sine, constructed on the resonance frequencies of the test tube, shows to be a very good alternative for the traditional periodic chirp. This signal offers the ability to obtain data for multiple frequencies in one measurement, without the danger of a low signal-to-noise ratio. The variability analysis in this paper clearly shows the advantages of the proposed multi-sine compared to the periodic chirp. The measurement procedure and the statistical analysis are validated by measuring the reflection ratio at a closed end and comparing the results with the theoretical value. Results of the testing of two building materials (an acoustic ceiling tile and linoleum) are presented and compared to supplier data.

  11. Scanning laser Doppler imaging may predict disease progression of localized scleroderma in children and young adults.

    PubMed

    Shaw, L J; Shipley, J; Newell, E L; Harris, N; Clinch, J G; Lovell, C R

    2013-07-01

    Localized scleroderma is a rare but potentially disfiguring and disabling condition. Systemic treatment should be started early in those with active disease in key functional and cosmetic sites, but disease activity is difficult to determine clinically. Superficial blood flow has been shown to correlate with disease activity in localized scleroderma. To examine whether superficial blood flow measured by laser Doppler imaging (LDI) has the potential to predict disease progression and therefore select patients for early systemic treatment. A group of 20 individuals had clinical assessment and scanning LDI blood-flow measurements of 32 affected body sites. After a mean follow-up of 8.7 months their clinical outcome was compared with the results of the initial LDI assessment. Eleven out of 15 patients with an assessment of active LDI had progressed clinically, and 16 out of the 17 scans with inactive LDI assessment had not progressed, giving a positive predictive value of 73% and a negative predictive value of 94%. We believe that LDI can be a useful tool in predicting disease progression in localized scleroderma, and it may help clinicians to decide which patients to treat early. © 2013 The Authors BJD © 2013 British Association of Dermatologists.

  12. Human abdomen recognition using camera and force sensor in medical robot system for automatic ultrasound scan.

    PubMed

    Bin Mustafa, Ammar Safwan; Ishii, Takashi; Matsunaga, Yoshiki; Nakadate, Ryu; Ishii, Hiroyuki; Ogawa, Kouji; Saito, Akiko; Sugawara, Motoaki; Niki, Kiyomi; Takanishi, Atsuo

    2013-01-01

    Physicians use ultrasound scans to obtain real-time images of internal organs, because such scans are safe and inexpensive. However, people in remote areas face difficulties to be scanned due to aging society and physician's shortage. Hence, it is important to develop an autonomous robotic system to perform remote ultrasound scans. Previously, we developed a robotic system for automatic ultrasound scan focusing on human's liver. In order to make it a completely autonomous system, we present in this paper a way to autonomously localize the epigastric region as the starting position for the automatic ultrasound scan. An image processing algorithm marks the umbilicus and mammary papillae on a digital photograph of the patient's abdomen. Then, we made estimation for the location of the epigastric region using the distances between these landmarks. A supporting algorithm distinguishes rib position from epigastrium using the relationship between force and displacement. We implemented these algorithms with the automatic scanning system into an apparatus: a Mitsubishi Electric's MELFA RV-1 six axis manipulator. Tests on 14 healthy male subjects showed the apparatus located the epigastric region with a success rate of 94%. The results suggest that image recognition was effective in localizing a human body part.

  13. Doppler Ultrasound Triggering for Cardiovascular MRI at 3T in a Healthy Volunteer Study.

    PubMed

    Kording, Fabian; Yamamura, Jin; Lund, Gunnar; Ueberle, Friedrich; Jung, Caroline; Adam, Gerhard; Schoennagel, Bjoern Philip

    2017-04-10

    Electrocardiogram (ECG) triggering for cardiac magnetic resonance (CMR) may be influenced by electromagnetic interferences with increasing magnetic field strength. The aim of this study was to evaluate the performance of Doppler ultrasound (DUS) as an alternative trigger technique for CMR in comparison to ECG and pulse oximetry (POX) at 3T and using different sequence types. Balanced turbo field echo two-dimensional (2D) short axis cine CMR and 2D phase-contrast angiography of the ascending aorta was performed in 11 healthy volunteers at 3T using ECG, DUS, and POX for cardiac triggering. DUS and POX triggering were compared to the reference standard of ECG in terms of trigger quality (trigger detection and temporal variability), image quality [endocardial blurring (EB)], and functional measurements [left ventricular (LV) volumetry and aortic blood flow velocimetry]. Trigger signal detection and temporal variability did not differ significantly between ECG/DUS (I = 0.6) and ECG/POX (P = 0.4). Averaged EB was similar for ECG, DUS, and POX (pECG/DUS = 0.4, pECG/POX = 0.9). Diastolic EB was significantly decreased for DUS in comparison to ECG (P = 0.02) and POX (P = 0.04). The LV function assessment and aortic blood flow were not significantly different. This study demonstrated the feasibility of DUS for gating human CMR at 3T. The magnetohydrodynamic effect did not significantly disturb ECG triggering in this small healthy volunteer study. DUS showed a significant improvement in diastolic EB but could not be identified as a superior trigger method. The potential benefit of DUS has to be evaluated in a larger clinical patient population.

  14. Determinants of coronary blood flow in humans: quantification by intracoronary Doppler and ultrasound.

    PubMed

    Wieneke, Heinrich; von Birgelen, Clemens; Haude, Michael; Eggebrecht, Holger; Möhlenkamp, Stefan; Schmermund, Axel; Böse, Dirk; Altmann, Christoph; Bartel, Thomas; Erbel, Raimund

    2005-03-01

    The direct determinants of coronary flow are lumen area and blood flow velocity; however, the precise mechanisms that control these factors are not fully understood. The aim of the present study was to assess by which mechanisms lumen area and coronary flow velocity interact with hemodynamic and morphometric factors, thereby influencing coronary flow. Intracoronary Doppler and ultrasound measurements were performed in 28 patients without coronary lumen irregularities. Flow velocity and lumen cross-sectional area were measured in the proximal segments of all three coronary arteries. Global lumen cross-sectional area and global flow were obtained by adding up the values of all three coronary arteries. Left ventricular mass was assessed by echocardiography. Stress-mass-heart rate and pressure-rate products reflecting myocardial oxygen demand were calculated. Global coronary flow increased during adenosine-induced hyperemia from 197 +/- 72 to 637 +/- 204 ml/min (P < 0.001). Global coronary flow closely correlated with the stress-mass-heart rate product (r = 0.62; P < 0.001). Looking at the two constituents of flow separately, global coronary cross-sectional area was closely related to left ventricular muscle mass (r = 0.61; P < 0.001), whereas mean coronary flow velocity at rest showed a strong linear relation with the pressure-rate product (r = 0.64; P < 0.001). There was no interaction between cross-sectional area and blood flow velocity in any of the coronary vessels. Coronary lumen size and flow velocity, the two determinants of coronary flow, are principally determined by different physiological factors. Long-term flow adaptation is achieved by an increase in coronary lumen size, whereas short-term myocardial oxygen requirements are met by changes in resting flow velocity.

  15. Treatment of in-vivo bladder tissue with electronically scanned high-intensity focused ultrasound

    NASA Astrophysics Data System (ADS)

    Feuillu, Benoit; Lacoste, Francois; Schlosser, Jacques; Vallancien, Guy

    1998-04-01

    Introduction: The efficacy of extracorporeal High Intensity Focused Ultrasound (HIFU) on bladder wall has been demonstrated. However, the treatment is still slow, needing about 15 min to treat 1 cm2. Objectives: Demonstrate the feasibility of HIFU with electronic scanning and reduce the during of HIFU treatments. Conclusions: Necrotic lesions on bladder posterior wall can be obtained with HIFU treatments using electronic scanning of the focal point. Average treatment duration with electronic scanning is reduced to 3 min 30 sec/cm2.

  16. High speed, wide velocity dynamic range Doppler optical coherence tomography (Part V): Optimal utilization of multi-beam scanning for Doppler and speckle variance microvascular imaging.

    PubMed

    Chen, Chaoliang; Cheng, Kyle H Y; Jakubovic, Raphael; Jivraj, Jamil; Ramjist, Joel; Deorajh, Ryan; Gao, Wanrong; Barnes, Elizabeth; Chin, Lee; Yang, Victor X D

    2017-04-03

    In this paper, a multi-beam scanning technique is proposed to optimize the microvascular images of human skin obtained with Doppler effect based methods and speckle variance processing. Flow phantom experiments were performed to investigate the suitability for combining multi-beam data to achieve enhanced microvascular imaging. To our surprise, the highly variable spot sizes (ranging from 13 to 77 μm) encountered in high numerical aperture multi-beam OCT system imaging the same target provided reasonably uniform Doppler variance and speckle variance responses as functions of flow velocity, which formed the basis for combining them to obtain better microvascular imaging without scanning penalty. In vivo 2D and 3D imaging of human skin was then performed to further demonstrate the benefit of combining multi-beam scanning to obtain improved signal-to-noise ratio (SNR) in microvascular imaging. Such SNR improvement can be as high as 10 dB. To our knowledge, this is the first demonstration of combining different spot size, staggered multiple optical foci scanning, to achieve enhanced SNR for blood flow OCT imaging.

  17. Ultrasound detection of pneumothorax compared with chest X-ray and computed tomography scan.

    PubMed

    Nagarsheth, Khanjan; Kurek, Stanley

    2011-04-01

    Pneumothorax after trauma can be a life threatening injury and its care requires expeditious and accurate diagnosis and possible intervention. We performed a prospective, single blinded study with convenience sampling at a Level I trauma center comparing thoracic ultrasound with chest X-ray and CT scan in the detection of traumatic pneumothorax. Trauma patients that received a thoracic ultrasound, chest X-ray, and chest CT scan were included in the study. The chest X-rays were read by a radiologist who was blinded to the thoracic ultrasound results. Then both were compared with CT scan results. One hundred and twenty-five patients had a thoracic ultrasound performed in the 24-month period. Forty-six patients were excluded from the study due to lack of either a chest X-ray or chest CT scan. Of the remaining 79 patients there were 22 positive pneumothorax found by CT and of those 18 (82%) were found on ultrasound and 7 (32%) were found on chest X-ray. The sensitivity of thoracic ultrasound was found to be 81.8 per cent and the specificity was found to be 100 per cent. The sensitivity of chest X-ray was found to be 31.8 per cent and again the specificity was found to be 100 per cent. The negative predictive value of thoracic ultrasound for pneumothorax was 0.934 and the negative predictive value for chest X-ray for pneumothorax was found to be 0.792. We advocate the use of chest ultrasound for detection of pneumothorax in trauma patients.

  18. Microwave thermal imaging of scanned focused ultrasound heating: Phantom results

    PubMed Central

    Meaney, Paul M.; Zhou, Tian; Fanning, Margaret W.; Geimer, Shireen D.; Paulsen, Keith D.

    2009-01-01

    We are developing a microwave tomographic imaging system capable of monitoring thermal distributions based on the temperature dependence of the recovered dielectric properties. The system has been coupled to a high intensity focused ultrasound (HIFU) therapy device which can be mechanically steered under computer control to generate arbitrarily shaped heating zones. Their integration takes advantage of the focusing capability of ultrasound for the therapy delivery and the isolation of the microwave imaging signal from the power deposition source to allow simultaneous treatment monitoring. We present several sets of phantom experiments involving different types of heating patterns that demonstrate the quality of both the spatial and temporal thermal imaging performance. This combined approach is adaptable to multiple anatomical sites and may have the potential to be developed into a viable alternative to current clinical temperature monitoring devices for HIFU, such magnetic resonance (MR) imaging. PMID:18608588

  19. Microwave thermal imaging of scanned focused ultrasound heating: phantom results.

    PubMed

    Meaney, Paul M; Zhou, Tian; Fanning, Margaret W; Geimer, Shireen D; Paulsen, Keith D

    2008-11-01

    We are developing a microwave tomographic imaging system capable of monitoring thermal distributions based on the temperature dependence of the recovered dielectric properties. The system has been coupled to a high intensity focused ultrasound (HIFU) therapy device which can be mechanically steered under computer control to generate arbitrarily shaped heating zones. Their integration takes advantage of the focusing capability of ultrasound for the therapy delivery and the isolation of the microwave imaging signal from the power deposition source to allow simultaneous treatment monitoring. We present several sets of phantom experiments involving different types of heating patterns that demonstrate the quality of both the spatial and temporal thermal imaging performance. This combined approach is adaptable to multiple anatomical sites and may have the potential to be developed into a viable alternative to current clinical temperature monitoring devices for HIFU, such magnetic resonance (MR) imaging.

  20. Comparison of time-frequency distribution techniques for analysis of simulated Doppler ultrasound signals of the femoral artery.

    PubMed

    Guo, Z; Durand, L G; Lee, H C

    1994-04-01

    The time-frequency distribution of the Doppler ultrasound blood flow signal is normally computed by using the short-time Fourier transform or autoregressive modeling. These two techniques require stationarity of the signal during a finite interval. This requirement imposes some limitations on the distribution estimate. In the present study, three new techniques for nonstationary signal analysis (the Choi-Williams distribution, a reduced interference distribution, and the Bessel distribution) were tested to determine their advantages and limitations for analysis of the Doppler blood flow signal of the femoral artery. For the purpose of comparison, a model stimulating the quadrature Doppler signal was developed, and the parameters of each technique were optimized based on the theoretical distribution. Distributions computed using these new techniques were assessed and compared with those computed using the short-time Fourier transform and autoregressive modeling. Three indexes, the correlation coefficient, the integrated squared error, and the normalized root-mean-squared error of the mean frequency waveform, were used to evaluate the performance of each technique. The results showed that the Bessel distribution performed the best, but the Choi-Williams distribution and autoregressive modeling are also techniques which can generate good time-frequency distributions of Doppler signals.

  1. Image analysis of placental issues using three-dimensional ultrasound and color power Doppler based on Support Vector Machine

    NASA Astrophysics Data System (ADS)

    Wang, Qi; Xu, Diyun; Liu, Jianguo

    2009-10-01

    With the development of medical science, three-dimensional ultrasound and color power Doppler tomography shooting placenta is widely used. To determine whether the fetus's development is abnormal or not is mainly through the analysis of the capillary's distribution of the obtained images which are shot by the Doppler scanner. In this classification process, we will adopt Support Vector Machine classifier. SVM achieves substantial improvements over the statistical learning methods and behaves robustly over a variety of different learning tasks. Furthermore, it is fully automatic, eliminating the need for manual parameter tuning and can solve the small sample problem wonderfully well. So SVM classifier is valid and reliable in the identification of placentas and is more accurate with the lower error rate.

  2. 3D camera assisted fully automated calibration of scanning laser Doppler vibrometers

    SciTech Connect

    Sels, Seppe Ribbens, Bart; Mertens, Luc; Vanlanduit, Steve

    2016-06-28

    Scanning laser Doppler vibrometers (LDV) are used to measure full-field vibration shapes of products and structures. In most commercially available scanning laser Doppler vibrometer systems the user manually draws a grid of measurement locations on a 2D camera image of the product. The determination of the correct physical measurement locations can be a time consuming and diffcult task. In this paper we present a new methodology for product testing and quality control that integrates 3D imaging techniques with vibration measurements. This procedure allows to test prototypes in a shorter period because physical measurements locations will be located automatically. The proposed methodology uses a 3D time-of-flight camera to measure the location and orientation of the test-object. The 3D image of the time-of-flight camera is then matched with the 3D-CAD model of the object in which measurement locations are pre-defined. A time of flight camera operates strictly in the near infrared spectrum. To improve the signal to noise ratio in the time-of-flight measurement, a time-of-flight camera uses a band filter. As a result of this filter, the laser spot of most laser vibrometers is invisible in the time-of-flight image. Therefore a 2D RGB-camera is used to find the laser-spot of the vibrometer. The laser spot is matched to the 3D image obtained by the time-of-flight camera. Next an automatic calibration procedure is used to aim the laser at the (pre)defined locations. Another benefit from this methodology is that it incorporates automatic mapping between a CAD model and the vibration measurements. This mapping can be used to visualize measurements directly on a 3D CAD model. Secondly the orientation of the CAD model is known with respect to the laser beam. This information can be used to find the direction of the measured vibration relatively to the surface of the object. With this direction, the vibration measurements can be compared more precisely with numerical

  3. Remote sensing of multi-level wind fields with high-energy airborne scanning coherent Doppler lidar.

    PubMed

    Rothermel, J; Olivier, L; Banta, R; Hardesty, R M; Howell, J; Cutten, D; Johnson, S; Menzies, R; Tratt, D M

    1998-01-19

    The atmospheric lidar remote sensing groups of NOAA Environmental Technology Laboratory, NASA Marshall Space Flight Center, and Jet Propulsion Laboratory have developed and flown a scanning, 1 Joule per pulse, CO2 coherent Doppler lidar capable of mapping a three-dimensional volume of atmospheric winds and aerosol backscatter in the planetary boundary layer, free troposphere, and lower stratosphere. Applications include the study of severe and non-severe atmospheric flows, intercomparisons with other sensors, and the simulation of prospective satellite Doppler lidar wind profilers. Examples of wind measurements are given for the marine boundary layer and near the coastline of the western United States.

  4. Remote Sensing of Multi-Level Wind Fields with High-Energy Airborne Scanning Coherent Doppler Lidar

    NASA Technical Reports Server (NTRS)

    Rothermel, Jeffry; Olivier, Lisa D.; Banta, Robert M.; Hardesty, R. Michael; Howell, James N.; Cutten, Dean R.; Johnson, Steven C.; Menzies, Robert T.; Tratt, David M.

    1997-01-01

    The atmospheric lidar remote sensing groups of NOAA Environmental Technology Laboratory, NASA Marshall Space Flight Center, and Jet Propulsion Laboratory have developed and flown a scanning, 1 Joule per pulse, CO2 coherent Doppler lidar capable of mapping a three-dimensional volume of atmospheric winds and aerosol backscatter in the troposphere and lower stratosphere. Applications include the study of severe and non-severe atmospheric flows, intercomparisons with other sensors, and the simulation of prospective satellite Doppler lidar wind profilers. Examples of wind measurements are given for the marine boundary layer and near the coastline of the western United States.

  5. Remote Sensing of Multi-Level Wind Fields with High-Energy Airborne Scanning Coherent Doppler Lidar

    NASA Technical Reports Server (NTRS)

    Rothermel, Jeffry; Olivier, Lisa D.; Banta, Robert M.; Hardesty, R. Michael; Howell, James N.; Cutten, Dean R.; Johnson, Steven C.; Menzies, Robert T.; Tratt, David M.

    1997-01-01

    The atmospheric lidar remote sensing groups of NOAA Environmental Technology Laboratory, NASA Marshall Space Flight Center, and Jet Propulsion Laboratory have developed and flown a scanning, 1 Joule per pulse, CO2 coherent Doppler lidar capable of mapping a three-dimensional volume of atmospheric winds and aerosol backscatter in the troposphere and lower stratosphere. Applications include the study of severe and non-severe atmospheric flows, intercomparisons with other sensors, and the simulation of prospective satellite Doppler lidar wind profilers. Examples of wind measurements are given for the marine boundary layer and near the coastline of the western United States.

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

    SciTech Connect

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

    2014-05-27

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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.

  8. Duplex ultrasound

    MedlinePlus

    ... duplex ultrasound combines: Traditional ultrasound: This uses sound waves that bounce off blood vessels to create pictures. Doppler ultrasound: This records sound waves reflecting off moving objects, such as blood, to ...

  9. Non-stationary blind deconvolution of medical ultrasound scans

    NASA Astrophysics Data System (ADS)

    Michailovich, Oleg V.

    2017-03-01

    In linear approximation, the formation of a radio-frequency (RF) ultrasound image can be described based on a standard convolution model in which the image is obtained as a result of convolution of the point spread function (PSF) of the ultrasound scanner in use with a tissue reflectivity function (TRF). Due to the band-limited nature of the PSF, the RF images can only be acquired at a finite spatial resolution, which is often insufficient for proper representation of the diagnostic information contained in the TRF. One particular way to alleviate this problem is by means of image deconvolution, which is usually performed in a "blind" mode, when both PSF and TRF are estimated at the same time. Despite its proven effectiveness, blind deconvolution (BD) still suffers from a number of drawbacks, chief among which stems from its dependence on a stationary convolution model, which is incapable of accounting for the spatial variability of the PSF. As a result, virtually all existing BD algorithms are applied to localized segments of RF images. In this work, we introduce a novel method for non-stationary BD, which is capable of recovering the TRF concurrently with the spatially variable PSF. Particularly, our approach is based on semigroup theory which allows one to describe the effect of such a PSF in terms of the action of a properly defined linear semigroup. The approach leads to a tractable optimization problem, which can be solved using standard numerical methods. The effectiveness of the proposed solution is supported by experiments with in vivo ultrasound data.

  10. Automated assessment of joint synovitis activity from medical ultrasound and power doppler examinations using image processing and machine learning methods.

    PubMed

    Cupek, Rafal; Ziębiński, Adam

    2016-01-01

    Rheumatoid arthritis is the most common rheumatic disease with arthritis, and causes substantial functional disability in approximately 50% patients after 10 years. Accurate measurement of the disease activity is crucial to provide an adequate treatment and care to the patients. The aim of this study is focused on a computer aided diagnostic system that supports an assessment of synovitis severity. This paper focus on a computer aided diagnostic system that was developed within joint Polish-Norwegian research project related to the automated assessment of the severity of synovitis. Semiquantitative ultrasound with power Doppler is a reliable and widely used method of assessing synovitis. Synovitis is estimated by ultrasound examiner using the scoring system graded from 0 to 3. Activity score is estimated on the basis of the examiner's experience or standardized ultrasound atlases. The method needs trained medical personnel and the result can be affected by a human error. The porotype of a computer-aided diagnostic system and algorithms essential for an analysis of ultrasonic images of finger joints are main scientific output of the MEDUSA project. Medusa Evaluation System prototype uses bone, skin, joint and synovitis area detectors for mutual structural model based evaluation of synovitis. Finally, several algorithms that support the semi-automatic or automatic detection of the bone region were prepared as well as a system that uses the statistical data processing approach in order to automatically localize the regions of interest. Semiquantitative ultrasound with power Doppler is a reliable and widely used method of assessing synovitis. Activity score is estimated on the basis of the examiner's experience and the result can be affected by a human error. In this paper we presented the MEDUSA project which is focused on a computer aided diagnostic system that supports an assessment of synovitis severity.

  11. Automated assessment of joint synovitis activity from medical ultrasound and power doppler examinations using image processing and machine learning methods

    PubMed Central

    Ziębiński, Adam

    2016-01-01

    Objectives Rheumatoid arthritis is the most common rheumatic disease with arthritis, and causes substantial functional disability in approximately 50% patients after 10 years. Accurate measurement of the disease activity is crucial to provide an adequate treatment and care to the patients. The aim of this study is focused on a computer aided diagnostic system that supports an assessment of synovitis severity. Material and methods This paper focus on a computer aided diagnostic system that was developed within joint Polish–Norwegian research project related to the automated assessment of the severity of synovitis. Semiquantitative ultrasound with power Doppler is a reliable and widely used method of assessing synovitis. Synovitis is estimated by ultrasound examiner using the scoring system graded from 0 to 3. Activity score is estimated on the basis of the examiner’s experience or standardized ultrasound atlases. The method needs trained medical personnel and the result can be affected by a human error. Results The porotype of a computer-aided diagnostic system and algorithms essential for an analysis of ultrasonic images of finger joints are main scientific output of the MEDUSA project. Medusa Evaluation System prototype uses bone, skin, joint and synovitis area detectors for mutual structural model based evaluation of synovitis. Finally, several algorithms that support the semi-automatic or automatic detection of the bone region were prepared as well as a system that uses the statistical data processing approach in order to automatically localize the regions of interest. Conclusions Semiquantitative ultrasound with power Doppler is a reliable and widely used method of assessing synovitis. Activity score is estimated on the basis of the examiner’s experience and the result can be affected by a human error. In this paper we presented the MEDUSA project which is focused on a computer aided diagnostic system that supports an assessment of synovitis severity

  12. Parabolic BM-scan technique for full range Doppler spectral domain optical coherence tomography.

    PubMed

    Jaillon, Franck; Makita, Shuichi; Yabusaki, Masaki; Yasuno, Yoshiaki

    2010-01-18

    A full range spectral domain optical coherence tomography (SD-OCT) technique that relies on the linear phase modulation of one of the interferometer arms has been widely utilized. Although this method is useful, the mirror image elimination is not perfect for samples in which regions with high axial motion exist. In this paper, we introduce a new modulation pattern to overcome this mirror image elimination failure. This new modulation is a parabolic phase modulation in the transverse scanning direction, and is applied to the SD-OCT reference beam by an electro-optic modulator. Flow phantom and in vivo experiments demonstrate that for moving structures with large velocities, this parabolic phase modulation technique presents better mirror image elimination than a standard linear phase modulation method. A direct consequence of this enhanced mirror image removal is an improved velocity range obtained with phase-resolved Doppler imaging. Consequently, applying the proposed technique in retinal blood flow measurements may be useful for ophthalmologic diagnosis.

  13. Modeling streamflow from coupled airborne laser scanning and acoustic Doppler current profiler data

    USGS Publications Warehouse

    Norris, Lam; Kean, Jason W.; Lyon, Steve

    2016-01-01

    The rating curve enables the translation of water depth into stream discharge through a reference cross-section. This study investigates coupling national scale airborne laser scanning (ALS) and acoustic Doppler current profiler (ADCP) bathymetric survey data for generating stream rating curves. A digital terrain model was defined from these data and applied in a physically based 1-D hydraulic model to generate rating curves for a regularly monitored location in northern Sweden. Analysis of the ALS data showed that overestimation of the streambank elevation could be adjusted with a root mean square error (RMSE) block adjustment using a higher accuracy manual topographic survey. The results of our study demonstrate that the rating curve generated from the vertically corrected ALS data combined with ADCP data had lower errors (RMSE = 0.79 m3/s) than the empirical rating curve (RMSE = 1.13 m3/s) when compared to streamflow measurements. We consider these findings encouraging as hydrometric agencies can potentially leverage national-scale ALS and ADCP instrumentation to reduce the cost and effort required for maintaining and establishing rating curves at gauging station sites similar to the Röån River.

  14. Neutral thermospheric dynamics observed with two scanning Doppler imagers: 2. Vertical winds

    NASA Astrophysics Data System (ADS)

    Anderson, C.; Conde, M.; McHarg, M. G.

    2012-03-01

    This article is the second in a series of three papers reporting on observations of the 630.0 nm thermospheric airglow emission by two spatially separated scanning Doppler imagers (SDI’s) in Alaska. In this article, line-of-sight wind measurements from these instruments in four common-volume regions lying along the great circle joining the two observatories have been used to derive estimates of the vertical wind in those common-volumes. These estimates are combined with the vertical winds measured directly in each of the station zeniths to resolve both the spatial and temporal variations of the vertical wind field. Data from four nights are presented as examples of the wave-like oscillations and frequently high spatial correlations that are observed. A statistical study of data from the full 19-night data set showed that the frequency of observing statistically significant correlation between vertical winds measured at separate locations decreased linearly with increasing separation. A linear fit to this trend indicated that for this particular location and orientation the largest separation over which statistically significant correlation would be expected to occur is approximately 540 km.

  15. Identification of pavement material properties using a scanning laser Doppler vibrometer

    NASA Astrophysics Data System (ADS)

    Hasheminejad, Navid; Vuye, Cedric; Van den Bergh, Wim; Dirckx, Joris; Leysen, Jari; Sels, Seppe; Vanlanduit, Steve

    2016-06-01

    This paper presents an inverse modeling approach to estimate mechanical properties of asphalt concrete (i.e. Young's modulus E, Poisson ratio ν and damping coefficients). Modal analysis was performed on an asphalt slab using a shaker to excite the specimen and an optical measurement system (a Scanning Laser Doppler Vibrometer or SLDV) to measure the velocity of a measurement grid on the surface of the slab. The SLDV has the ability to measure the vibration pattern of an object with high accuracy, short testing time and without making any contact. The measured data were used as inputs for a frequency domain model parameter estimation method (the Polymax estimator). Meanwhile, natural frequencies and damping ratios of the system were calculated using a Finite Element Modeling (FEM) method. Then, the Modal Assurance Criterion (MAC) was used to pair the mode shapes of the structure determined by measurements and estimated by FEM. By changing the inputs of the FEM analysis (E, ν and damping coefficients of the material) iteratively and minimizing the discrepancy between paired natural frequencies and damping ratios of the system estimated using the Polymax estimator and calculated by FEM, the Young's modulus, Poisson ratio and damping coefficients of the asphalt slab were estimated.

  16. Measurements of underwater acoustic pressure fields using a scanning laser Doppler vibrometer

    NASA Astrophysics Data System (ADS)

    Carroll, Gerard P.

    2004-05-01

    Laser Doppler vibrometers (LDV) are designed to measure structural vibration velocity by sensing the phase shift in the laser signal reflected from a vibrating source. It is known that index of refraction modulations resulting from acoustic pressure distributions along a laser light path will also cause a phase shift. Simpson et al. [J. Acoust. Soc. Am. 99(4), 2521(A) (1996)] have investigated this acousto-optic phase modulation as a possible contaminating effect for underwater LDV vibration measurements. This paper will investigate acousto-optic phase modulations measured by a scanning LDV as a method for measuring pressure radiating from underwater vibrating surfaces. This is done by passing the laser beam through the radiating pressure field and measuring the backscattered laser signal which is reflected off a rigid and retroreflective surface (outside the pressure field). It is shown experimentally, using the average pressure measured with an LDV over a plane in the vicinity of a vibrating structure, that the pressure at a far-field location normal to the plane can be determined.

  17. Investigation of three-dimensional vibration measurement by a single scanning laser Doppler vibrometer

    NASA Astrophysics Data System (ADS)

    Chen, Da-Ming; Zhu, W. D.

    2017-01-01

    A scanning laser Doppler vibrometer (SLDV) has been widely used in non-contact vibration measurement. This paper presents a novel investigation of three-dimensional (3D) vibration measurement by a single SLDV sequentially placed at three different positions, where 3D vibration is defined as three vibration components along axes of a specified measurement coordinate system (MCS), which can give more precise knowledge of structural dynamic characteristics. A geometric model of the SLDV is proposed and a vibrometer coordinate system (VCS) based on the geometric model is defined and fixed on the SLDV. The pose of a SLDV with respect to a MCS is expressed in the form of a translation vector and a direction cosine matrix from the VCS to the MCS, which can be calculated by four or more target points with known coordinates in both the MCS and the VCS. An improved method based on the least squares method and singular value decomposition is proposed to obtain the pose of the SLDV. Compared with an inverse method, the proposed method can yield an orthogonal direction cosine matrix and be applicable to a two-dimensional structure. Effects of the number of target points on the accuracy and stability of the proposed method are investigated. With three direction cosine matrices of three different positions obtained by the proposed method, measured vibration velocities along laser line-of-sight directions can be transformed to vibration components along axes of the MCS. An experiment was conducted to measure 3D vibration of a target point on a beam under sinusoidal excitation by a single SLDV sequentially placed at three different positions. Vibration components along axes of the MCS obtained by the single SLDV were in good agreement with those from a commercial Polytec 3D scanning laser vibrometer PSV-500-3D.

  18. Power Doppler ultrasound phenotyping of expanding versus collapsed popliteal lymph nodes in murine inflammatory arthritis.

    PubMed

    Bouta, Echoe M; Ju, Yawen; Rahimi, Homaira; de Mesy-Bentley, Karen L; Wood, Ronald W; Xing, Lianping; Schwarz, Edward M

    2013-01-01

    Rheumatoid arthritis is a chronic inflammatory disease manifested by episodic flares in affected joints that are challenging to predict and treat. Longitudinal contrast enhanced-MRI (CE-MRI) of inflammatory arthritis in tumor necrosis factor-transgenic (TNF-Tg) mice has demonstrated that popliteal lymph nodes (PLN) increase in volume and contrast enhancement during the pre-arthritic "expanding" phase of the disease, and then suddenly "collapse" during knee flare. Given the potential of this biomarker of arthritic flare, we aimed to develop a more cost-effective means of phenotyping PLN using ultrasound (US) imaging. Initially we attempted to recapitulate CE-MRI of PLN with subcutaneous footpad injection of US microbubbles (DEFINITY®). While this approach allowed for phenotyping via quantification of lymphatic sinuses in PLN, which showed a dramatic decrease in collapsed PLN versus expanding or wild-type (WT) PLN, electron microscopy demonstrated that DEFINITY® injection also resulted in destruction of the lymphatic vessels afferent to the PLN. In contrast, Power Doppler (PD) US is innocuous to and efficiently quantifies blood flow within PLN of WT and TNF-Tg mice. PD-US demonstrated that expanding PLN have a significantly higher normalized PD volume (NPDV) versus collapsed PLN (0.553 ± 0.007 vs. 0.008 ± 0.003; p<0.05). Moreover, we define the upper (>0.030) and lower (<0.016) quartile NPDVs in this cohort of mice, which serve as conservative thresholds to phenotype PLN as expanding and collapsed, respectively. Interestingly, of the 12 PLN phenotyped by the two methods, there was disagreement in 4 cases in which they were determined to be expanding by CE-MRI and collapsed by PD-US. Since the adjacent knee had evidence of synovitis in all 4 cases, we concluded that the PD-US phenotyping was correct, and that this approach is currently the safest and most cost-effective in vivo approach to phenotype murine PLN as a biomarker of arthritic flare.

  19. Template-based Quality Assessment of the Doppler Ultrasound Signal for Fetal Monitoring.

    PubMed

    Valderrama, Camilo E; Marzbanrad, Faezeh; Stroux, Lisa; Clifford, Gari D

    2017-01-01

    One dimensional Doppler Ultrasound (DUS) is a low cost method for fetal auscultation. However, accuracy of any metrics derived from the DUS signals depends on their quality, which relies heavily on operator skills. In low resource settings, where skill levels are sparse, it is important for the device to provide real time signal quality feedback to allow the re-recording of data. Retrospectively, signal quality assessment can help remove low quality recordings when processing large amounts of data. To this end, we proposed a novel template-based method, to assess DUS signal quality. Data used in this study were collected from 17 pregnant women using a low-cost transducer connected to a smart phone. Recordings were split into 1990 segments of 3.75 s duration, and hand labeled for quality by three independent annotators. The proposed template-based method uses Empirical Mode Decomposition (EMD) to allow detection of the fetal heart beats and segmentation into short, time-aligned temporal windows. Templates were derived for each 15 s window of the recordings. The DUS signal quality index (SQI) was calculated by correlating the segments in each window with the corresponding running template using four different pre-processing steps: (i) no additional preprocessing, (ii) linear resampling of each beat, (iii) dynamic time warping (DTW) of each beat and (iv) weighted DTW of each beat. The template-based SQIs were combined with additional features based on sample entropy and power spectral density. To assess the performance of the method, the dataset was split into training and test subsets. The training set was used to obtain the best combination of features for predicting the DUS quality using cross validation, and the test set was used to estimate the classification accuracy using bootstrap resampling. A median out of sample classification accuracy on the test set of 85.8% was found using three features; template-based SQI, sample entropy and the relative power in the

  20. Colour Doppler ultrasound hemodynamic characteristics of patients with priapism before and after therapeutic interventions.

    PubMed

    Chiou, Rei K; Aggarwal, Himanshu; Chiou, Christopher R; Broughton, Fleur; Liu, Susan

    2009-08-01

    BACKGROUND: Information in the literature on the hemodynamic characteristics of priapism, especially after therapeutic intervention, is very limited. We analyzed our colour Doppler ultrasound (CDU) studies performed for patients with various durations of priapism before and after therapeutic intervention. METHODS: We reviewed 52 CDU studies for 24 patients with priapism before and after treatment for the period 1997-2007. The duration of priapism ranged from 4 hours to 8 days. We performed 17 CDU studies in 8 patients who presented with a duration of priapism of 7 hours or less, 9 studies in 4 patients who presented with duration of priapism of more than 20 hours, 23 studies in 11 patients referred to us after they had failed prior therapeutic intervention at other institutions and 3 studies in 1 patient with priapism related to perineal trauma. RESULTS: Among the 8 patients who presented with a duration of priapism of 7 hours or less, CDU studies on presentation showed detectible cavernosal arterial flow in all except 1 study. Among the 4 patients who presented with a duration of more than 20 hours, the studies showed no detectible cavernosal arterial blood flow. We repeated CDU studies after therapeutic intervention, and they showed restoration of cavernosal arterial flow with relief of veno-occlusive status. Among the 11 patients in whom prior treatments failed before they were referred to us, CDU studies performed on presentation showed no detectible cavernosal arterial flow in 10 of the 11 patients. We performed 12 CDU studies in 8 patients after placing a penile cavernosa-dorsal vein (CD) shunt. We observed the presence of blood flow in the CD shunt, indicating its patency in all 8 patients. Some patients showed high cavernosal arterial flow (peak systolic velocity [PSV] up to 27.6 cm/s) after surgery. These patients appeared to have residual priapism of primarily arteriogenic status that improved after observation. CONCLUSION: After therapeutic intervention

  1. Template-based Quality Assessment of the Doppler Ultrasound Signal for Fetal Monitoring

    PubMed Central

    Valderrama, Camilo E.; Marzbanrad, Faezeh; Stroux, Lisa; Clifford, Gari D.

    2017-01-01

    One dimensional Doppler Ultrasound (DUS) is a low cost method for fetal auscultation. However, accuracy of any metrics derived from the DUS signals depends on their quality, which relies heavily on operator skills. In low resource settings, where skill levels are sparse, it is important for the device to provide real time signal quality feedback to allow the re-recording of data. Retrospectively, signal quality assessment can help remove low quality recordings when processing large amounts of data. To this end, we proposed a novel template-based method, to assess DUS signal quality. Data used in this study were collected from 17 pregnant women using a low-cost transducer connected to a smart phone. Recordings were split into 1990 segments of 3.75 s duration, and hand labeled for quality by three independent annotators. The proposed template-based method uses Empirical Mode Decomposition (EMD) to allow detection of the fetal heart beats and segmentation into short, time-aligned temporal windows. Templates were derived for each 15 s window of the recordings. The DUS signal quality index (SQI) was calculated by correlating the segments in each window with the corresponding running template using four different pre-processing steps: (i) no additional preprocessing, (ii) linear resampling of each beat, (iii) dynamic time warping (DTW) of each beat and (iv) weighted DTW of each beat. The template-based SQIs were combined with additional features based on sample entropy and power spectral density. To assess the performance of the method, the dataset was split into training and test subsets. The training set was used to obtain the best combination of features for predicting the DUS quality using cross validation, and the test set was used to estimate the classification accuracy using bootstrap resampling. A median out of sample classification accuracy on the test set of 85.8% was found using three features; template-based SQI, sample entropy and the relative power in the

  2. Color Doppler ultrasound criteria to diagnose varicoceles: correlation of a new scoring system with physical examination.

    PubMed

    Chiou, R K; Anderson, J C; Wobig, R K; Rosinsky, D E; Matamoros, A; Chen, W S; Taylor, R J

    1997-12-01

    Color Doppler ultrasound (CDU) diagnostic criteria for varicoceles are poorly defined, and the role of CDU in diagnosing varicoceles is controversial. The purpose of this study is to assess the diagnostic accuracy of CDU for varicoceles compared to physical examination. We prospectively studied 64 patients with CDU and collected the following data: maximum diameter of scrotal veins, the presence of a venous plexus, sum of the diameter of up to six veins of the plexus, and the duration and amplitude of flow change on Valsalva maneuver. To avoid interphysician variation, all patients were examined by one designated senior urologist with the sonographer remaining unaware of the findings. CDU parameters of 127 testis units in 64 patients were analyzed and compared to the physical findings. Fifty-nine testis units were positive and 57 units were negative for varicocele on physical examination. In 11 testis units, results of physical examination were inconclusive regarding the presence of varicocele. The commonly accepted CDU criterion for varicocele (maximal vein diameter of 3 mm or greater) had a sensitivity of 53% and specificity of 91% compared to physical examination. We developed a new scoring system incorporating the maximal venous diameter (score 0 to 3), the presence of a venous plexus and the sum of the diameters of veins in the plexus (score 0 to 3), and the change of flow on Valsalva maneuver (score 0 to 3). Using a total score of 4 or more to define the presence of CDU-positive varicocele, we observed a sensitivity of 93% and a specificity of 85% when compared to physical examination. All moderate to large varicoceles found on physical examination were positive by CDU diagnosis using the scoring system, but the same group had only a 68% positive rate by traditional CDU diagnostic criteria. Using the proposed new scoring system, CDU has been shown to be a reliable and accurate method of diagnosis for varicoceles compared to the current reference standard

  3. Doppler ultrasound surveillance in deep tunneling compressed-air work with Trimix breathing: bounce dive technique compared to saturation-excursion technique.

    PubMed

    Vellinga, T P van Rees; Sterk, W; de Boer, A G E M; van der Beek, A J; Verhoeven, A C; van Dijk, F J H

    2008-01-01

    The Western Scheldt Tunneling Project in The Netherlands provided a unique opportunity to evaluate two deep-diving techniques with Doppler ultrasound surveillance. Divers used the bounce diving techniques for repair and maintenance of the TBM. The tunnel boring machine jammed at its deepest depth. As a result the work time was not sufficient. The saturation diving technique was developed and permitted longer work time at great depth. Thirty-one divers were involved in this project. Twenty-three divers were examined using Doppler ultrasound. Data analysis addressed 52 exposures to Trimix at 4.6-4.8 bar gauge using the bounce technique and 354 exposures to Trimix at 4.0-6.9 bar gauge on saturation excursions. No decompression incidents occurred with either technique during the described phase of the project. Doppler ultrasound revealed that the bubble loads assessed in both techniques were generally low. We find out, that despite longer working hours, shorter decompression times and larger physical workloads, the saturation-excursion technique was associated with significant lower bubble grades than in the bounce technique using Doppler Ultrasound. We conclude that the saturation-excursion technique with Trimix is a good option for deep and long exposures in caisson work. The Doppler technique proved valuable, and it should be incorporated in future compressed-air work.

  4. Improved 3D reconstruction algorithm for ultrasound B-scan image with freehand tracker

    NASA Astrophysics Data System (ADS)

    Zhao, Shuangren; Suri, Jasjit

    2010-03-01

    EM algorithm for the reconstruction of freehand B-Scan ultrasound image was developed by Joao M. Sanches et al. The reconstruction has a parameter K which can be adjusted so that the results can be smoother or sharper depending to the value of K. In order to make the image smoother inside the organs but sharper in their boundaries simultaneously, we introduced a improved EM algorithm: EM algorithm with a diffusion filer or is referred as EMD algorithm. There was a cubic average filter inside the loop of the iteration of the EM algorithm. This average filter is replaced by a diffusion filter in the EMD algorithm. The diffusion filter offers an additional parameter Kd which can be used to adjust the reconstructed image with better optimization in both smoothness insider the human organ and sharpness in its boundary. Two above mentioned reconstruction algorithms for the freehand B-scan ultrasound image are compared through the simulation and the phantom measurements. In the simulation, strong noises are added to the ultrasound frame data. The parameters of two algorithms are optimized to get smallest errors. The errors are compared between two algorithms with optimized parameters. For the measurement with phantom, the Eigen's tracker system is used to continuously measure the coordinates of the ultrasound probe. The ultrasound B-scan frame is synchronously recorded with the probe coordinates. Zonare ultrasound machine is used to acquire the 2D frame images. The segmentation of the reconstruction results is done. The segmentation volumes of the prostate phantoms are compared. The results shows that EMD algorithm is better at reducing the noises and keeping the image edge comparing to EM algorithm. Eigen's tracker is cacaple to acquire freehand ultrasound data for a 3D image reconstruction with high quality.

  5. Focal bowel wall changes detected with colour Doppler ultrasound: diagnostic value in acute non-diverticular diseases of the colon.

    PubMed

    Danse, E M; Jamart, J; Hoang, P; Laterre, P F; Kartheuser, A; Van Beers, B E

    2004-11-01

    We performed a study to determine if colour Doppler findings may help to identify the cause of wall thickening in acute non-diverticular diseases of the colon. The study group included 66 patients admitted to the emergency department with a final diagnosis of infectious colitis (n=23), inflammatory colitis (n=10), ischaemic colitis (n=23) and malignant tumours (n=10). The following ultrasound features were assessed: maximal wall thickness, wall stratification, arterial flow in the colonic wall and arteriolar resistive index. Higher values of wall thickness were observed in malignant tumour (18.2+/-6.2 mm, p<0.001). Moderately thickened wall (6.6+/-1.3 mm, p< or =0.06), preserved stratification (90% versus 46% in the remainder of the study population) and lower resistive index (0.51+/-0.10, p< or =0.05) were significantly related to inflammatory colitis. Absence of arterial flow was more frequently observed in ischaemia (43% versus 12% in the remainder of the study population). In conclusion, despite some overlap, both ultrasound and colour Doppler features are helpful in the differential diagnosis of colonic thickening related to non-diverticular colonic lesions.

  6. Accuracy of velocity and shear rate measurements using pulsed Doppler ultrasound: a comparison of signal analysis techniques.

    PubMed

    Markou, C P; Ku, D N

    1991-01-01

    An experimental investigation was instituted to evaluate the performance of Doppler ultrasound signal processing techniques for measuring fluid velocity under well-defined flow conditions using a 10-MHz multigated pulsed ultrasound instrument. Conditions of fully developed flow in a rigid, circular tube were varied over a Reynolds number range between 500 and 8000. The velocity across the tube was determined using analog and digital zero crossing detectors and three digital spectrum estimators. Determination of the Doppler frequency from analog or digital zero crossing detectors gave accurate velocity values for laminar and moderately turbulent flow away from the wall (0.969 less than or equal to r less than or equal to 0.986). Three digital spectrum estimators, Fast Fourier Transform, Burg autoregressive method, and minimum variance method, were slightly more accurate than the zero crossing detector (0.984 less than or equal to r less than or equal to 0.994), especially at points close to the walls and with higher levels of turbulence. Steep velocity gradients and transit-time-effects from high velocities produced significantly larger errors in velocity measurement. Wall shear rate estimates were most precise when calculated using the position of the wall and two velocity points. The calculated wall shears were within 20%-30% of theoretically predicted values.

  7. [The analysis and comparison of different edge detection algorithms in ultrasound B-scan images].

    PubMed

    Zhang, Luo-ping; Yang, Bo-yuan; Wang, Chun-hong

    2006-05-01

    In this paper, some familiar algorithms of edge detection in ultrasound B-scan images are analyzed and studied. The results show that Sobel, Prewitt and Laplacian operators are sensitive to noise, Hough transform adapts to the whole detection, while LoG algorithm's average is zero and it couldn't change the whole dynamic area. Accordingly LoG algorithm is preferable.

  8. The role of intraoperative micro-Doppler ultrasound in verifying proper clip placement in intracranial aneurysm surgery.

    PubMed

    Siasios, Ioannis; Kapsalaki, Eftychia Z; Fountas, Kostas N

    2012-10-01

    Aneurysmal subarachnoid hemorrhage constitutes a clinical entity associated with high mortality and morbidity. It is widely accepted that improper clip placement may have as a result of incomplete aneurysm occlusion and/or partial or complete obstruction of an adjacent vessel. Various modalities, including intraoperative or postoperative digital subtracting angiography, near-infrared indocyanine green angiography, micro-Doppler ultrasonography (MDU), and neurophysiological studies, have been utilized for verifying proper clip placement. The aim of our study was to review the role of MDU during aneurysmal surgery. A literature search was performed using any possible combination of the following terms: "aneurysm," "brain," "cerebral," "clip," "clipping," "clip malpositioning," "clip repositioning," "clip suboptimal positioning," "Doppler," "intracranial," "microsurgery," "micro-Doppler," "residual neck," "ultrasonography," "ultrasound," and "vessel occlusion". Additionally, reference lists from the retrieved articles were reviewed for identifying any additional articles. Case reports and miniseries were excluded. A total of 19 series employing intraoperative MDU during aneurysmal microsurgery were retrieved. All studies demonstrated that MDU accuracy is extremely high. The highest reported false-positive rate of MDU was 2 %, while the false-negative rate was reported as high as 1.6 %. It has been demonstrated that the presence of subarachnoid hemorrhage, specific anatomic locations, and large size may predispose to improper clip placement. Intraoperative MDU's technical limitations and weaknesses are adequately identified, in order to minimize the possibility of any misinterpretations. Intraoperative MDU constitutes a safe, accurate, and low cost imaging modality for evaluating blood flow and for verifying proper clip placement during microsurgical clipping.

  9. Successful stent implantation guided by intravascular ultrasound and a Doppler guidewire without contrast injection in a patient with allergy to iodinated contrast media.

    PubMed

    Okura, Hiroyuki; Nezuo, Shintaro; Yoshida, Kiyoshi

    2011-07-01

    Presence of allergy to iodinated contrast may prevent percutaneous coronary intervention (PCI) to be performed. We present a 76-year-old male with a history of allergic reaction to iodinated contrast who successfully underwent intravascular ultrasound (IVUS) and a Doppler guidewire-guided PCI. Stent size was determined based on IVUS. After PCI, stent expansion and a lack of edge dissection or incomplete apposition were confirmed by IVUS and a good antegrade coronary flow was confirmed by a Doppler guidewire. Thus, PCI without contrast injection under IVUS and a Doppler guidewire-guidance may be feasible in selected patients with allergy to iodinated contrast.

  10. Reduction of the clutter component in Doppler ultrasound signals based on singular value decomposition: a simulation study.

    PubMed

    Ledoux, L A; Brands, P J; Hoeks, A P

    1997-01-01

    In pulsed Doppler ultrasound systems, the ultrasound radiofrequency (RF) signals received can be employed to estimate noninvasively the time-dependent blood velocity distribution within and artery. The RF signals are composed of signals originating from clutter (e.g., vessel walls) and scatterers (e.g., red blood cells). The clutter, which is induced by stationary or slowly-moving structure interfaces, must be suppressed to get reliable estimates of the mean blood flow velocities. In conventional pulsed Doppler systems, this is achieved with a static temporal high-pass filter. The static cut-off frequency and the roll-off of these filters cause the culture not always to be optimally suppressed. This paper introduces a clutter removal filter that is based on Singular Value Decomposition (SVD). Unlike conventional high-pass filters, which take into account only the information of the temporal direction, the SVD filter makes use of the information of the temporal and spatial directions. The advantage of this approach is that it does not matter where the clutter is located in the RF signal. The performance of the SVD filter is examined with computer-generated Doppler RF signals. The results are compared with those of standard linear regression (SLR) filter. The performance of the SVD filter is good, especially if a large temporal window (i.e., approximately 100 RF signals) is applied, which improves the performance for low blood flow velocities, A major disadvantage of the SVD filter is its computational complexity, which increases considerably for larger temporal windows.

  11. The development of a combined b-mode, ARFI, and spectral Doppler ultrasound imaging system for investigating cardiovascular stiffness and hemodynamics

    NASA Astrophysics Data System (ADS)

    Doherty, Joshua R.; Dumont, Douglas M.; Trahey, Gregg E.

    2011-03-01

    The progression of atherosclerotic disease, caused by the formation of plaques within arteries, is a complex process believed to be a function of the localized mechanical properties and hemodynamic loading associated with the arterial wall. It is hypothesized that measurements of vascular stiffness and wall-shear rate (WSR) may provide important information regarding vascular remodeling, endothelial function, and the growth of soft-lipid filled plaques that could help a clinician better diagnose a patient's risk of clinical events such as stroke. To that end, the approach taken in this work was to combine conventional B-mode, Acoustic Radiation Force Impulse (ARFI), Shear Wave Elasticity Imaging (SWEI), and spectral Doppler techniques into a single imaging system capable of simultaneously measuring the tissue displacements and WSR throughout the cardiac cycle and over several heartbeats. Implemented on a conventional scanner, the carotid arteries of human subjects were scanned to demonstrate the initial in vivo feasibility of the method. Two non-invasive ultrasound based imaging methods, SAD-SWEI and SAD-Gated Imaging, were developed that measure ARF-induced on-axis tissue displacements, off-axis transverse wave velocities, and WSR throughout the cardiac cycle. Human carotid artery scans were performed in vivo on 5 healthy subjects. Statistical differences were observed in both on-axis proximal wall displacements and transverse wave velocities during diastole compared to systole.

  12. Settings and artefacts relevant in colour/power Doppler ultrasound in rheumatology.

    PubMed

    Torp-Pedersen, S T; Terslev, L

    2008-02-01

    The paper explains the most important parameters for the use of colour and power Doppler in rheumatology. Recommendations for machine settings are given. The commonly encountered artefacts and their importance for image interpretation are explained.

  13. Standardization of the first-trimester fetal cardiac examination using spatiotemporal image correlation with tomographic ultrasound and color Doppler imaging.

    PubMed

    Turan, S; Turan, O M; Ty-Torredes, K; Harman, C R; Baschat, A A

    2009-06-01

    The challenges of the first-trimester examination of the fetal heart may in part be overcome by technical advances in three-dimensional (3D) ultrasound techniques. Our aim was to standardize the first-trimester 3D imaging approach to the cardiac examination to provide the most consistent and accurate display of anatomy. Low-risk women with normal findings on first-trimester screening at 11 to 13 + 6 weeks had cardiac ultrasound using the following sequence: (1) identification of the four-chamber view; (2) four-dimensional (4D) volume acquisition with spatiotemporal image correlation (STIC) and color Doppler imaging (angle = 20 degrees, sweep 10 s); (3) offline, tomographic ultrasound imaging (TUI) analysis with standardized starting plane (four-chamber view), slice number and thickness; (4) assessment of fetal cardiac anatomy (four-chamber view, cardiac axis, size and symmetry, atrioventricular valves, great arteries and descending aorta) with and without color Doppler. 107 consecutive women (age, 16-42 years, body mass index 17.2-50.2 kg/m(2)) were studied. A minimum of three 3D volumes were obtained for each patient, transabdominally in 91.6%. Fetal motion artifact required acquisition of more than three volumes in 20%. The median time for TUI offline analysis was 100 (range, 60-240) s. Individual anatomic landmarks were identified in 89.7-99.1%. Visualization of all structures in one panel was observed in 91 patients (85%). Starting from a simple two-dimensional cardiac landmark-the four-chamber view-the standardized STIC-TUI technique enables detailed segmental cardiac evaluation of the normal fetal heart in the first trimester. (c) 2009 ISUOG.

  14. Renal power Doppler ultrasonographic evaluation of children with acute pyelonephritis.

    PubMed

    Shajari, Ahmad; Nafisi-Moghadam, Reza; Malek, Mahrooz; Smaili, Agha; Fallah, Mahmud; Pahlusi, Ali

    2011-01-01

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

  15. The variation in frequency locations in Doppler ultrasound spectra for maximum blood flow velocities in narrowed vessels.

    PubMed

    Zhang, Yingyun; Zhang, Yufeng; Gao, Lian; Deng, Li; Hu, Xiao; Zhang, Kexin; Li, Haiyan

    2017-07-28

    This study assessed the variation in the frequency locations in the Doppler ultrasound spectra for the maximum blood flow velocities of in vessels with different degrees of bilaterally axisymmetric stenosis. This was done by comparing the relationship between the velocity distributions and corresponding Doppler power spectra. First, a geometric vessel model with axisymmetric stenosis was established. This made it possible to obtain the blood flow velocity distributions for different degrees of stenosis from the solutions of the Navier-Stokes equations. Then, the Doppler spectra were calculated for the entire segment of the vessel that was covered by the sound field. Finally, the maximum frequency locations for the spectra were determined based on the intersections of the maximum values chosen from the calculated blood flow velocity distributions and their corresponding spectra. The computational analysis showed that the maximum frequencies, which corresponded to the maximum blood flow velocities for different degrees of stenosis, were located at different positions along the spectral falling edges. The location for a normal (stenosis free) vessel was in the middle of the falling edge. For vessels with increasing degrees of stenosis, this location shifted approximately linearly downward along the falling edge. For 40% stenosis, the location reached a position at the falling edge of 0.32. Results obtained using the Field II simulation tool demonstrated the validity of the theoretical analysis and calculations, and may help to improve the maximum velocity estimation accuracy for Doppler blood flow spectra in stenosed vessels. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

  16. Learning-based scan plane identification from fetal head ultrasound images

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoming; Annangi, Pavan; Gupta, Mithun; Yu, Bing; Padfield, Dirk; Banerjee, Jyotirmoy; Krishnan, Kajoli

    2012-03-01

    Acquisition of a clinically acceptable scan plane is a pre-requisite for ultrasonic measurement of anatomical features from B-mode images. In obstetric ultrasound, measurement of gestational age predictors, such as biparietal diameter and head circumference, is performed at the level of the thalami and cavum septum pelucidi. In an accurate scan plane, the head can be modeled as an ellipse, the thalami looks like a butterfly, the cavum appears like an empty box and the falx is a straight line along the major axis of a symmetric ellipse inclined either parallel to or at small angles to the probe surface. Arriving at the correct probe placement on the mother's belly to obtain an accurate scan plane is a task of considerable challenge especially for a new user of ultrasound. In this work, we present a novel automated learning-based algorithm to identify an acceptable fetal head scan plane. We divide the problem into cranium detection and a template matching to capture the composite "butterfly" structure present inside the head, which mimics the visual cues used by an expert. The algorithm uses the stateof- the-art Active Appearance Models techniques from the image processing and computer vision literature and tie them to presence or absence of the inclusions within the head to automatically compute a score to represent the goodness of a scan plane. This automated technique can be potentially used to train and aid new users of ultrasound.

  17. Why Current Doppler Ultrasound Methodology Is Inaccurate in Assessing Cerebral Venous Return: The Alternative of the Ultrasonic Jugular Venous Pulse

    PubMed Central

    2016-01-01

    Assessment of cerebral venous return is growing interest for potential application in clinical practice. Doppler ultrasound (DUS) was used as a screening tool. However, three meta-analyses of qualitative DUS protocol demonstrate a big heterogeneity among studies. In an attempt to improve accuracy, several authors alternatively measured the flow rate, based on the product of the time average velocity with the cross-sectional area (CSA). However, also the quantification protocols lacked of the necessary accuracy. The reasons are as follows: (a) automatic measurement of the CSA assimilates the jugular to a circle, while it is elliptical; (b) the use of just a single CSA value in a pulsatile vessel is inaccurate; (c) time average velocity assessment can be applied only in laminar flow. Finally, the tutorial describes alternative ultrasound calculation of flow based on the Womersley method, which takes into account the variation of the jugular CSA overtime. In the near future, it will be possible to synchronize the electrocardiogram with the brain inflow (carotid distension wave) and with the outflow (jugular venous pulse) in order to nicely have a noninvasive ultrasound picture of the brain-heart axis. US jugular venous pulse may have potential use in neurovascular, neurocognitive, neurosensorial, and neurodegenerative disorders. PMID:27006525

  18. Evaluation of Pacific obstetric and gynaecological ultrasound scanning capabilities, personnel, equipment and workloads.

    PubMed

    Kodikara, Hemal; Mitchell, Jenny; Ekeroma, Alec; Stone, Peter

    2010-12-17

    There are no published data on the coverage, training or experience of ultrasound services in the Pacific. This study aimed to obtain information on the knowledge, experience and training of ultrasound operators and scanning equipment and workloads in the Pacific region. Participants for the survey were recruited by post, via the Pacific Society of Reproductive Health (PSRH) website and at the PSRH conference. Questions obtained information on ultrasound scanning capabilities, personnel, equipment and workloads in the Pacific region 30 respondents from 17 hospitals in 11 countries provided completed questionnaires. Close to 50% of the responses were from Fiji. The majority of respondents were sonographers or obstetricians. Lack of transvaginal probes (7/17) in some facilities limit accuracy of early pregnancy scanning. 17/17 respondents felt an advanced course would be the preferred type of course. There is a sound basic level of ultrasound being performed in the Pacific region. A multimodal training programme, incorporating a practical hands-on course based in New Zealand, combined with CD/published materials appears to be the best method of developing more advanced skills in order to optimise antenatal care in the region.

  19. Nearly automated analysis of coronary Doppler flow velocity from transthoracic ultrasound images: validation with manual tracings.

    PubMed

    Magagnin, V; Delfino, L; Cerutti, S; Turiel, M; Caiani, E G

    2007-05-01

    Coronary flow velocity reserve is obtained by manual tracings of transthoracic coronary Doppler flow velocity profiles as the ratio of stress versus baseline diastolic peak velocities. This approach introduces subjectivity in the measurements and limits the information which could be exploited from the Doppler velocity profile. Accordingly, our goals were to develop a technique for nearly automated detection of Doppler coronary flow velocity profile, and automatically compute both conventional and additional amplitude, derivative and temporal parameters, and validate it with manual tracings. A total of 100 patients (17 normals, 15 patients with severe coronary stenosis, 41 with connective tissue disease and 27 with diabetes mellitus) were studied. Linear correlation and Bland-Altman analyses showed that the proposed method was highly accurate and repeatable compared to the manual measurements. Comparison between groups evidenced significant differences in some of the automated parameters, thus representing potentially additional indices useful for the noninvasive diagnosis of microcirculatory or coronary artery disease.

  20. Determination of the envelope function (maximum velocity curve) in Doppler ultrasound flow velocity diagrams

    NASA Astrophysics Data System (ADS)

    Tschirren, Juerg; Lauer, Ronald M.; Sonka, Milan

    2000-06-01

    This paper presents a new approach for the evaluation of Doppler flow velocity diagrams, obtained during brachial artery flow mediated dilatation (FMD) studies. The velocity diagrams are stored as image sequences on VCR tape. For this reason standard signal processing methods can not be used. A method for determination of blood velocity envelopes from image data is reported that uses Doppler-data specific heuristic to achieve high accuracy and robustness. The approach was tested in 40 Doppler blood flow images. Comparisons with manually defined independent standards demonstrated a very good correlation in determined peak velocity values (r equals 0.993) and flow envelope areas (r equals 0.996). The method is currently tested in a large volume clinical study.

  1. Comparison of high definition oscillometric and Doppler ultrasound devices with invasive blood pressure in anaesthetized dogs.

    PubMed

    Seliškar, Alenka; Zrimšek, Petra; Sredenšek, Jerneja; Petrič, Aleksandra D

    2013-01-01

    To use the American College of Veterinary Internal Medicine (ACVIM) validation criteria to evaluate the performance of high definition oscillometric (HDO) and Doppler blood pressure measurement techniques against invasive blood pressure measurements in anaesthetized dogs. Prospective clinical study. Twenty client-owned dogs. Invasive blood pressure was measured using a catheter inserted into a pedal artery and an electronic transducer. The sites of cuff placement for the HDO measurements were the mid antebrachium or the proximal tail and, for the Doppler technique, the distal tibia. Agreement between invasive and non-invasive blood pressure measurements was estimated by the Bland-Altman method. Only 10% and 34% of Doppler measurements were within 10 and 20 mmHg of invasive blood pressure values, respectively. The Doppler device failed to meet the ACVIM validation criteria for blood pressure measurement devices. The best agreement between HDO and invasive blood pressure measurement technique was observed for mean arterial blood pressure (MAP); 67% and 95% of readings were within 10 and 20 mmHg of invasive blood pressure values respectively. In addition, 52% and 87% of diastolic arterial blood pressure (DAP) measurements were within 10 and 20 mmHg of invasive readings. High definition oscillometric readings did not meet ACVIM recommended limits for SAP. The Doppler technique overestimated and the HDO device showed limited agreement with invasive blood pressure measurement in anaesthetized dogs. High definition oscillometry met most of the ACVIM requirements for MAP and DAP while the Doppler technique did not. © 2012 The Authors. Veterinary Anaesthesia and Analgesia. © 2012 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesiologists.

  2. Assessment of the Effects of Low-Level Laser Therapy on the Thyroid Vascularization of Patients with Autoimmune Hypothyroidism by Color Doppler Ultrasound

    PubMed Central

    Höfling, Danilo Bianchini; Chavantes, Maria Cristina; Juliano, Adriana G.; Cerri, Giovanni G.; Knobel, Meyer; Yoshimura, Elisabeth M.; Chammas, Maria Cristina

    2012-01-01

    Background. Chronic autoimmune thyroiditis (CAT) frequently alters thyroid vascularization, likely as a result of the autoimmune process. Objective. To evaluate the effects of low-level laser therapy (LLLT) on the thyroid vascularization of patients with hypothyroidism induced by CAT using color Doppler ultrasound parameters. Methods. In this randomized clinical trial, 43 patients who underwent levothyroxine replacement for CAT-induced hypothyroidism were randomly assigned to receive either 10 sessions of LLLT (L group, n = 23) or 10 sessions of a placebo treatment (P group, n = 20). Color Doppler ultrasounds were performed before and 30 days after interventions. To verify the vascularity of the thyroid parenchyma, power Doppler was performed. The systolic peak velocity (SPV) and resistance index (RI) in the superior (STA) and inferior thyroid arteries (ITAs) were measured by pulsed Doppler. Results. The frequency of normal vascularization of the thyroid lobes observed in the postintervention power Doppler examination was significantly higher in the L than in the P group (P = 0.023). The pulsed Doppler examination revealed an increase in the SPV of the ITA in the L group compared with the P group (P = 0.016). No significant differences in the SPV of the STA and in the RI were found between the groups. Conclusion. These results suggest that LLLT can ameliorate thyroid parenchyma vascularization and increase the SPV of the ITA of patients with hypothyroidism caused by CAT. PMID:23316383

  3. Wideband Doppler Ultrasound-guided Mini-endoscopic Combined Intrarenal Surgery as an Effective and Safe Procedure for Management of Large Renal Stones: A Preliminary Report.

    PubMed

    Inoue, Takaaki; Kinoshita, Hidefumi; Okada, Shinsuke; Hamamoto, Shuzo; Taguchi, Makoto; Murota, Takashi; Matsuda, Tadashi

    2016-09-01

    To evaluate the efficacy and safety of wideband Doppler ultrasound-guided mini-endoscopic combined intrarenal surgery (mini-ECIRS) for large renal stones. This study included 41 patients with large renal stones (>30 mm) treated by mini-ECIRS using a retrograde flexible ureteroscope and miniature nephroscope by wideband Doppler ultrasound guidance in the modified Valdivia position from January 2013 to September 2015. Surgical parameters, including the stone-free rate, operative time, complications (especially hemorrhagic complications), and hemoglobin drop were recorded and analyzed. Univariate analysis was performed to identify risk factors for a hemoglobin drop of ≥1 g/dL. The mean stone size, including staghorn calculi in 41.4% of cases, was 45.5 ± 14.7 mm. Percutaneous access into the calices using wideband Doppler ultrasound was successful in all cases. The mean total operative time was 158.4 ± 51.3 minutes. The mean mini-ECIRS time (from first percutaneous puncture to end of procedure) was 106.2 ± 36.0 minutes. The initial stone-free rate was 73.2% (n = 30). The final stone-free rate after auxiliary treatment was 97.5% (n = 40). The mean hemoglobin drop was 0.54 ± 0.65 g/dL. Three (7.3%) postoperative modified Clavien grade II complications occurred. Univariate analysis revealed no significant risk factors for a hemoglobin drop of ≥1 g/dL. Wideband Doppler ultrasound-guided renal puncture is safe and feasible. Wideband Doppler ultrasound-guided mini-ECIRS is a beneficial, versatile, and safe treatment option for management of large renal stones of >30 mm. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. A GPU based high-definition ultrasound digital scan conversion algorithm

    NASA Astrophysics Data System (ADS)

    Zhao, Mingchang; Mo, Shanjue

    2010-02-01

    Digital scan conversion algorithm is the most computational intensive part of B-mode ultrasound imaging. Traditionally, in order to meet the requirements of real-time imaging, digital scan conversion algorithm often traded off image quality for speed, such as the use of simple image interpolation algorithm, the use of look-up table to carry out polar coordinates transform and logarithmic compression. This paper presents a GPU-based high-definition real-time ultrasound digital scan conversion algorithm implementation. By rendering appropriate proxy geometry, we can implement a high precision digital scan conversion pipeline, including polar coordinates transform, bi-cubic image interpolation, high dynamic range tone reduction, line average and frame persistence FIR filtering, 2D post filtering, fully in the fragment shader of GPU at real-time speed. The proposed method shows the possibility of updating exist FPGA or ASIC based digital scan conversion implementation to low cost GPU based high-definition digital scan conversion implementation.

  5. Listening to speech recruits specific tongue motor synergies as revealed by transcranial magnetic stimulation and tissue-Doppler ultrasound imaging.

    PubMed

    D'Ausilio, A; Maffongelli, L; Bartoli, E; Campanella, M; Ferrari, E; Berry, J; Fadiga, L

    2014-01-01

    The activation of listener's motor system during speech processing was first demonstrated by the enhancement of electromyographic tongue potentials as evoked by single-pulse transcranial magnetic stimulation (TMS) over tongue motor cortex. This technique is, however, technically challenging and enables only a rather coarse measurement of this motor mirroring. Here, we applied TMS to listeners' tongue motor area in association with ultrasound tissue Doppler imaging to describe fine-grained tongue kinematic synergies evoked by passive listening to speech. Subjects listened to syllables requiring different patterns of dorso-ventral and antero-posterior movements (/ki/, /ko/, /ti/, /to/). Results show that passive listening to speech sounds evokes a pattern of motor synergies mirroring those occurring during speech production. Moreover, mirror motor synergies were more evident in those subjects showing good performances in discriminating speech in noise demonstrating a role of the speech-related mirror system in feed-forward processing the speaker's ongoing motor plan.

  6. Listening to speech recruits specific tongue motor synergies as revealed by transcranial magnetic stimulation and tissue-Doppler ultrasound imaging

    PubMed Central

    D'Ausilio, A.; Maffongelli, L.; Bartoli, E.; Campanella, M.; Ferrari, E.; Berry, J.; Fadiga, L.

    2014-01-01

    The activation of listener's motor system during speech processing was first demonstrated by the enhancement of electromyographic tongue potentials as evoked by single-pulse transcranial magnetic stimulation (TMS) over tongue motor cortex. This technique is, however, technically challenging and enables only a rather coarse measurement of this motor mirroring. Here, we applied TMS to listeners’ tongue motor area in association with ultrasound tissue Doppler imaging to describe fine-grained tongue kinematic synergies evoked by passive listening to speech. Subjects listened to syllables requiring different patterns of dorso-ventral and antero-posterior movements (/ki/, /ko/, /ti/, /to/). Results show that passive listening to speech sounds evokes a pattern of motor synergies mirroring those occurring during speech production. Moreover, mirror motor synergies were more evident in those subjects showing good performances in discriminating speech in noise demonstrating a role of the speech-related mirror system in feed-forward processing the speaker's ongoing motor plan. PMID:24778384

  7. Three-dimensional power Doppler ultrasound diagnosis and laparoscopic management of a pregancy in a previous cesarean scar.

    PubMed

    Wang, Chin-Jung; Yuen, Leung-To; Yen, Chih-Feng; Lee, Chyi-Long; Soong, Yung-Kuei

    2004-12-01

    An ectopic pregnancy developing in a previous Cesarean section scar is a rare event, and there is still a lack of information concerning the adequacy of management strategies. So far, no modality can guarantee the integrity of the uterus. We report the case of a 29-year-old woman with three Cesarean deliveries who was transferred to our hospital with a diagnosis of cervical pregnancy. Transvaginal three-dimensional power Doppler ultrasound revealed a well-encapsulated bulging mass displacing anteriorly over the lower anterior uterine wall sounding with an irregular course and branching vessels. The diagnosis of pregnancy in a previous Cesarean scar was made. Laparoscopic ligation of bilateral uterine arteries followed by excision of the ectopic pregnant mass was undertaken, and the patient's uterus was successfully preserved. Conservative management with the laparoscopic approach may be a safe and effective alternative to hysterectomy in patients with a pregnacy in a previous Cesarean scar.

  8. Towards increased data transmission rate for a three-class metabolic brain-computer interface based on transcranial Doppler ultrasound.

    PubMed

    Myrden, Andrew; Kushki, Azadeh; Sejdić, Ervin; Chau, Tom

    2012-10-24

    In this study, we conducted an offline analysis of transcranial Doppler (TCD) ultrasound recordings to investigate potential methods for increasing data transmission rate in a TCD-based brain-computer interface. Cerebral blood flow velocity was recorded within the left and right middle cerebral arteries while nine able-bodied participants alternated between rest and two different mental activities (word generation and mental rotation). We differentiated these three states using a three-class linear discriminant analysis classifier while the duration of each state was varied between 5 and 30s. Maximum classification accuracies exceeded 70%, and data transmission rate was maximized at 1.2 bits per minute, representing a four-fold increase in data transmission rate over previous two-class analysis of TCD recordings. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  9. Sizing of Emboli in Flowing Blood Using Pulse Doppler Ultrasound and the Embolus-To Power Ratio.

    NASA Astrophysics Data System (ADS)

    Moehring, Mark Alan

    The embolus to blood ratio (EBR) theoretical model describing pulse Doppler ultrasound observations of emboli in flowing blood is summarized. The EBR model uses the backscattered signal power from blood in the Doppler sample volume as a reference from which to assess embolus size and composition. This EBR is independent of attenuation and reflection loss in intervening tissues between probe and bloodflow. An in vitro investigation is presented that tests the validity of the EBR model. The experimental apparatus includes a novel phantom for Doppler observation of circulating emboli and a Doppler system which uses 1.6 and 2.4 MHz concurrently for interrogation of an embolus. The phantom contains a tubeless flow conduit inside a polyacrylamide gel and a blood-mimicking fluid flowing in the conduit. Time series Doppler shift data which are gathered while polystyrene microsphere "emboli" transit the sample volume are post -processed to calculate the EBR on each embolic signature. EBR measurements from microspheres of three different diameters are summarized and shown to contain pronounced and systematic variability. The hypothesis is presented that this variability is due to a small speed of sound mismatch between the gel and the blood-mimicking fluid, a phenomenon anticipated in vivo. This speed of sound mismatch results in beam refraction and a non-uniformly insonated sample volume (thereby causing variability in embolus signatures). A three dimensional theoretical study is presented that models beam refraction resulting from speed of sound mismatch between the blood mimicking fluid and the surrounding gel. A Monte Carlo study of the EBR behavior in the presence of beam refraction is performed and yields similar results to the data obtained in vitro. This study is evidence that the experimental signal variability is due to speed of sound mismatch between blood-mimicking fluid and gel. A method of extracting embolus size from the dual frequency EBR data based on the

  10. Continuous wave ultrasonic Doppler tomography

    PubMed Central

    Liang, Haidong-Dong; Tsui, Chun Sing Louis; Halliwell, Michael; Wells, Peter N. T.

    2011-01-01

    In continuous wave ultrasonic Doppler tomography (DT), the ultrasonic beam moves relative to the scanned object to acquire Doppler-shifted frequency spectra which correspond to cross-range projections of the scattering and reflecting structures within the object. The relative motion can be circular or linear. These data are then backprojected to reconstruct the two-dimensional image of the object cross section. By using coherent processing, the spatial resolution of ultrasonic DT is close to an order of magnitude better than that of traditional pulse-echo imaging at the same ultrasound frequency. PMID:22866236

  11. New adaptive clutter rejection based on spectral analysis for ultrasound color Doppler imaging: phantom and in vivo abdominal study.

    PubMed

    Geunyong Park; Sunmi Yeo; Jae Jin Lee; Changhan Yoon; Hyun-Woo Koh; Hyungjoon Lim; Youngtae Kim; Hwan Shim; Yangmo Yoo

    2014-01-01

    Effective rejection of time-varying clutter originating from slowly moving vessels and surrounding tissues is important for depicting hemodynamics in ultrasound color Doppler imaging (CDI). In this paper, a new adaptive clutter rejection method based on spectral analysis (ACR-SA) is presented for suppressing nonstationary clutter. In ACR-SA, tissue and flow characteristics are analyzed by singular value decomposition and tissue acceleration of backscattered Doppler signals to determine an appropriate clutter filter from a set of clutter filters. To evaluate the ACR-SA method, 20 frames of complex baseband data were acquired by a commercial ultrasound system equipped with a research package (Accuvix V10, Samsung Medison, Seoul, Korea) using a 3.5-MHz convex array probe by introducing tissue movements to the flow phantom (Gammex 1425 A LE, Gammex, Middleton, WI, USA). In addition, 20 frames of in vivo abdominal data from five volunteers were captured. From the phantom experiment, the ACR-SA method provided 2.43 dB (p <; 0.001) and 1.09 dB ( ) improvements in flow signal-to-clutter ratio (SCR) compared to static (STA) and down-mixing (ACR-DM) methods. Similarly, it showed smaller values in fractional residual clutter area (FRCA) compared to the STA and ACR-DM methods (i.e., 2.3% versus 5.4% and 3.7%, respectively, ). The consistent improvements in SCR from the proposed ACR-SA method were obtained with the in vivo abdominal data (i.e., 4.97 dB and 3.39 dB over STA and ACR-DM, respectively). The ACR-SA method showed less than 1% FRCA values for all in vivo abdominal data. These results indicate that the proposed ACR-SA method can improve image quality in CDI by providing enhanced rejection of nonstationary clutter.

  12. Operator Auditory Perception and Spectral Quantification of Umbilical Artery Doppler Ultrasound Signals

    PubMed Central

    Thuring, Ann; Brännström, K. Jonas; Ewerlöf, Maria; Hernandez-Andrade, Edgar; Ley, David; Lingman, Göran; Liuba, Karina; Maršál, Karel; Jansson, Tomas

    2013-01-01

    Objective An experienced sonographer can by listening to the Doppler audio signals perceive various timbres that distinguish different types of umbilical artery flow despite an unchanged pulsatility index (PI). Our aim was to develop an objective measure of the Doppler audio signals recorded from fetoplacental circulation in a sheep model. Methods Various degrees of pathological flow velocity waveforms in the umbilical artery, similar to those in human complicated pregnancies, were induced by microsphere embolization of the placental bed (embolization model, 7 lamb fetuses, 370 Doppler recordings) or by fetal hemodilution (anemia model, 4 lamb fetuses, 184 recordings). A subjective 11-step operator auditory scale (OAS) was related to conventional Doppler parameters, PI and time average mean velocity (TAM), and to sound frequency analysis of Doppler signals (sound frequency with the maximum energy content [MAXpeak] and frequency band at maximum level minus 15 dB [MAXpeak-15 dB] over several heart cycles). Results We found a negative correlation between the OAS and PI: median Rho −0.73 (range −0.35– −0.94) and −0.68 (range −0.57– −0.78) in the two lamb models, respectively. There was a positive correlation between OAS and TAM in both models: median Rho 0.80 (range 0.58–0.95) and 0.90 (range 0.78–0.95), respectively. A strong correlation was found between TAM and the results of sound spectrum analysis; in the embolization model the median r was 0.91 (range 0.88–0.97) for MAXpeak and 0.91 (range 0.82–0.98) for MAXpeak-15 dB. In the anemia model, the corresponding values were 0.92 (range 0.78–0.96) and 0.96 (range 0.89–0.98), respectively. Conclusion Audio-spectrum analysis reflects the subjective perception of Doppler sound signals in the umbilical artery and has a strong correlation to TAM-velocity. This information might be of importance for clinical management of complicated pregnancies as an addition to conventional Doppler parameters

  13. Very different performance of the power Doppler modalities of several ultrasound machines ascertained by a microvessel flow phantom.

    PubMed

    Ten Cate, David F; Luime, Jolanda J; van der Ven, Myrthe; Hazes, Johanna M W; Kooiman, Klazina; de Jong, Nico; Bosch, Johannes G

    2013-10-24

    In many patients with rheumatoid arthritis (RA) subclinical disease activity can be detected with ultrasound (US), especially using power Doppler US (PDUS). However, PDUS may be highly dependent on the type of machine. This could create problems both in clinical trials and in daily clinical practice. To clarify how the PDUS signal differs between machines we created a microvessel flow phantom. The flow phantom contained three microvessels (150, 1000, 2000 microns). A syringe pump was used to generate flows. Five US machines were used. Settings were optimised to assess the lowest detectable flow for each US machine. The minimal detectable flow velocities showed very large differences between the machines. Only two of the machines may be able to detect the very low flows in the capillaries of inflamed joints. There was no clear relation with price. One of the lower-end machines actually performed best in all three vessel sizes. We created a flow phantom to test the sensitivity of US machines to very low flows in small vessels. The sensitivity of the power Doppler modalities of 5 different machines was very different. The differences found between the machines are probably caused by fundamental differences in processing of the PD signal or internal settings inaccessible to users. Machines considered for PDUS assessment of RA patients should be tested using a flow phantom similar to ours. Within studies, only a single machine type should be used.

  14. Very different performance of the power Doppler modalities of several ultrasound machines ascertained by a microvessel flow phantom

    PubMed Central

    2013-01-01

    Introduction In many patients with rheumatoid arthritis (RA) subclinical disease activity can be detected with ultrasound (US), especially using power Doppler US (PDUS). However, PDUS may be highly dependent on the type of machine. This could create problems both in clinical trials and in daily clinical practice. To clarify how the PDUS signal differs between machines we created a microvessel flow phantom. Methods The flow phantom contained three microvessels (150, 1000, 2000 microns). A syringe pump was used to generate flows. Five US machines were used. Settings were optimised to assess the lowest detectable flow for each US machine. Results The minimal detectable flow velocities showed very large differences between the machines. Only two of the machines may be able to detect the very low flows in the capillaries of inflamed joints. There was no clear relation with price. One of the lower-end machines actually performed best in all three vessel sizes. Conclusions We created a flow phantom to test the sensitivity of US machines to very low flows in small vessels. The sensitivity of the power Doppler modalities of 5 different machines was very different. The differences found between the machines are probably caused by fundamental differences in processing of the PD signal or internal settings inaccessible to users. Machines considered for PDUS assessment of RA patients should be tested using a flow phantom similar to ours. Within studies, only a single machine type should be used. PMID:24286540

  15. A multi-dimensional approach for describing internal bleeding in an artery: implications for Doppler ultrasound guiding HIFU hemostasis

    NASA Astrophysics Data System (ADS)

    Yang, Di; Zhang, Dong; Guo, Xiasheng; Gong, Xiufen; Fei, Xingbo

    2008-09-01

    Doppler ultrasound has shown promise in detecting and localizing internal bleeding. A mathematical approach was developed to describe the internal bleeding of the injured artery surrounded by tissue. This approach consisted of a two-dimensional (2D) model describing the injured vessel and a one-dimensional model (1D) mimicking the downstream of the vessel system. The validity of this approach was confirmed by both the numerical simulation and in vivo measurement of a normal porcine femoral artery. Furthermore, the artery was injured using a 16-gauge needle to model a penetrating injury. The velocity waveform at the puncture site was modeled and compared with those at the upstream and downstream of the artery. The results demonstrated that there was a significant increase in magnitude and a phase lag for the peak systolic velocity at the injury site. These results were qualitatively in agreement with the in vivo experiment. Flow turbulence indicated by this approach was also observed in a color Doppler image in the form of a checkered color pattern. This approach might be useful for quantitative internal bleeding detection and localization. Also, the phase lag of the peak systolic velocity was indicated to be potential in the application of internal bleeding detection.

  16. Bilateral Circumscribed Posterior Keratoconus: Visualization by Ultrasound Biomicroscopy and Slit-Scanning Topography Analysis

    PubMed Central

    Rejdak, Robert; Nowomiejska, Katarzyna; Haszcz, Dariusz; Jünemann, Anselm G. M.

    2012-01-01

    This paper documents a rare nonprogressive developmental disorder—bilateral circumscribed posterior keratoconus—in a 60-year-old man referred for a cataract surgery. For the first time ultrasound biomicroscopy was used to visualise the local anterior bulging of the posterior corneal surface with concomitant thinning of the stroma. The amount of localized posterior depression, corneal thickness and the refractive power of both the posterior and anterior corneal curvature were measured using slit-scanning topography analysis (Orbscan). PMID:22496963

  17. Structure-symptom relationship with wide-area ultrasound scanning of knee osteoarthritis

    PubMed Central

    Podlipská, Jana; Koski, Juhani M.; Kaukinen, Päivi; Haapea, Marianne; Tervonen, Osmo; Arokoski, Jari P.; Saarakkala, Simo

    2017-01-01

    The aetiology of knee pain in osteoarthritis (OA) is heterogeneous and its relationship with structural changes and function is unclear. Our goal was to determine the prevalence of wide-area scanned ultrasound-defined knee OA structural features and their association with pain and functional impairment in 79 symptomatic and 63 asymptomatic subjects. All subjects underwent ultrasound knee wide-area scanning and the severity of articular cartilage degeneration, the presence and size of osteophytes, and meniscal extrusion were evaluated. Subjects filled in a self-administrated questionnaire on present knee pain, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) on clinical symptoms and function over the past week. Cartilage changes were the most prevalent followed by lateral meniscal extrusion, osteophytes and medial meniscal extrusion. The global femoral cartilage grade associated strongly with pain and the WOMAC index. Site-specifically, early medial cartilage changes and thinning in sulcus and lateral site were associated with symptoms. The presence of femoral lateral osteophytes was also associated with both outcomes. Using the novel wide-area ultrasound scanning technique, we were able to confirm the negative impact of femoral cartilage OA changes on clinical symptoms. Presence, not necessarily size, of lateral femoral osteophytes was also associated with increased pain and disability. PMID:28295049

  18. Ultrasound line-by-line scanning method of spatial-temporal active cavitation mapping for high-intensity focused ultrasound.

    PubMed

    Ding, Ting; Zhang, Siyuan; Fu, Quanyou; Xu, Zhian; Wan, Mingxi

    2014-01-01

    This paper presented an ultrasound line-by-line scanning method of spatial-temporal active cavitation mapping applicable in a liquid or liquid filled tissue cavities exposed by high-intensity focused ultrasound (HIFU). Scattered signals from cavitation bubbles were obtained in a scan line immediately after one HIFU exposure, and then there was a waiting time of 2 s long enough to make the liquid back to the original state. As this pattern extended, an image was built up by sequentially measuring a series of such lines. The acquisition of the beamformed radiofrequency (RF) signals for a scan line was synchronized with HIFU exposure. The duration of HIFU exposure, as well as the delay of the interrogating pulse relative to the moment while HIFU was turned off, could vary from microseconds to seconds. The feasibility of this method was demonstrated in tap-water and a tap-water filled cavity in the tissue-mimicking gelatin-agar phantom as capable of observing temporal evolutions of cavitation bubble cloud with temporal resolution of several microseconds, lateral and axial resolution of 0.50 mm and 0.29 mm respectively. The dissolution process of cavitation bubble cloud and spatial distribution affected by cavitation previously generated were also investigated. Although the application is limited by the requirement for a gassy fluid (e.g. tap water, etc.) that allows replenishment of nuclei between HIFU exposures, the technique may be a useful tool in spatial-temporal cavitation mapping for HIFU with high precision and resolution, providing a reference for clinical therapy.

  19. Flow patterns in carotid bifurcation models using pulsed Doppler ultrasound: effect of concentric vs. eccentric stenosis on turbulence and recirculation.

    PubMed

    Poepping, Tamie L; Rankin, Richard N; Holdsworth, David W

    2010-07-01

    Hemodynamics play a significant role in stroke risk, where thrombus formation may be accelerated in regions of slow or recirculating flow, high shear and increased turbulence. An in vitro investigation was performed with pulsed Doppler ultrasound (DUS) using the complete spectral data to investigate the three-dimensional (3-D) distribution of advanced parameters that may have potential for making a more specific in vivo diagnosis of carotid disease and stroke risk. The effect of stenosis symmetry and the potential of DUS spectral parameters for visualizing regions of recirculation or turbulence were explored. DUS was used to map pulsatile flow in four model geometries representing two different plaque symmetries (eccentricity) and two stenosis severities (mild, severe). Qualitative comparisons were made with flow patterns visualized using digital particle imaging. Color-encoded maps of DUS spectral parameters (mean velocity, spectral-broadening index and turbulence intensity) clearly distinguished regions of slow or recirculating flow and disturbed or turbulent flow. Distinctly different flow patterns resulted from stenoses of equal severity but different eccentricity. Noticeable differences were seen in both the size and location of recirculation zones and in the paths of high-velocity jets. Highly elevated levels of turbulence intensity were seen distal to severe stenosis. Results demonstrated the importance of plaque shape, which is typically not considered in standard diagnosis, in addition to stenosis severity. Copyright 2010 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  20. Remote Sensing of Wind Fields and Aerosol Distribution with Airborne Scanning Doppler Lidar

    NASA Technical Reports Server (NTRS)

    Rothermel, Jeffry; Cutten, Dean R.; Johnson, Steven C.; Jazembski, Maurice; Arnold, James E. (Technical Monitor)

    2001-01-01

    The coherent Doppler laser radar (lidar), when operated from an airborne platform, is a unique tool for the study of atmospheric and surface processes and features. This is especially true for scientific objectives requiring measurements in optically-clear air, where other remote sensing technologies such as Doppler radar are typically at a disadvantage. The atmospheric lidar remote sensing groups of several US institutions, led by Marshall Space Flight Center, have developed an airborne coherent Doppler lidar capable of mapping the wind field and aerosol structure in three dimensions. The instrument consists of an eye-safe approx. 1 Joule/pulse lidar transceiver, telescope, scanner, inertial measurement unit, and flight computer system to orchestrate all subsystem functions and tasks. The scanner is capable of directing the expanded lidar beam in a variety of ways, in order to extract vertically-resolved wind fields. Horizontal resolution is approx. 1 km; vertical resolution is even finer. Winds are obtained by measuring backscattered, Doppler-shifted laser radiation from naturally-occurring aerosol particles (of order 1 micron diameter). Measurement coverage depends on aerosol spatial distribution and composition. Velocity accuracy has been verified to be approx. 1 meter per second. A variety of applications have been demonstrated during the three flight campaigns conducted during 1995-1998. Examples will be shown during the presentation. In 1995, boundary layer winds over the ocean were mapped with unprecedented resolution. In 1996, unique measurements were made of. flow over the complex terrain of the Aleutian Islands; interaction of the marine boundary layer jet with the California coastal mountain range; a weak dry line in Texas - New Mexico; the angular dependence of sea surface scattering; and in-flight radiometric calibration using the surface of White Sands National Monument. In 1998, the first measurements of eyewall and boundary layer winds within a

  1. Basic technique and anatomically imposed limitations of confocal scanning laser Doppler flowmetry at the optic nerve head level.

    PubMed

    Sehi, Mitra

    2011-02-01

    Many studies have suggested an association between blood flow dysregulation and glaucomatous damage to the optic nerve. Confocal scanning laser Doppler flowmetry (CSLDF) is a technique that measures the capillary blood flow of the retina and optic nerve head and provides a two-dimensional map of ocular perfusion in these areas. This review discusses the anatomy of the anterior optic nerve vasculature and the capabilities and limitations of the CSLDF. Methods to minimize error and to acquire more reliable measurements of capillary blood flow are also outlined. © 2009 The Authors. Journal compilation © 2009 Acta Ophthalmol.

  2. [Doppler flow imaging characteristics of blood supply of uterine fibroids on the therapeutic dosage of ultrasound ablation].

    PubMed

    Chen, Jin-yun; Chen, Wen-zhi; Zhu, Li; Tang, Liang-dan; Deng, Yong-bin; Liu, Ying-jiang; Zou, Jian-zhong; Bai, Jin; Wang, Zhi-biao

    2011-06-01

    To explore the relationship between therapeutic dosage of ultrasound ablation in treatment of uterine fibroids and imaging characteristics of bloody supply of uterine fibroids by color Doppler ultrasound imaging. One hundred and forty-two patients with 168 fibroids were treated by ultrasound ablation. Before treatment, bloody supply of fibroids were classified into grade 0 - 4 by ultrasonography. Three patients lost follow-up with contrast MRI exam within 1 month after treatment, so 165 fibroids were enrolled in this study. Bloody supplies were 9 fibroids in grade 0, 34 fibroids in grade 1, 35 fibroids in grade 2, 55 fibroids in grade 3 and 32 fibroids in grade 4. After 1 month treatment, the treated area without blood supply and ratio of ablation were measured by contrast MRI to evaluate the efficacy of thermal ablation and compare status of blood supple based different therapeutic dosage. According to International Reditherapy for Society (SIR) standard, adverse effect and score of pain were evaluated. (1) Ratio of ablation based: ratios of ablation were 79% in grade 0, 89% in grade 1, 92% in grade 2, 86% in grade 3, 71% in grade 4. It reached statistical difference when blood supply of grade 0 compared with those of grade 2 and 3 (P < 0.05) and blood supply of grade 4 compared with those of grade 1, 2, 3 (P < 0.05). (2) Factor of energy efficiency: factor of energy efficiency were 13.19 J/mm(3) in degree 0, 9.54 J/mm(3) in degree 1, 12.91 J/mm(3) in degree 2, 17.83 J/mm(3) in degree 3 and 28.10 J/mm(3) in degree 4. Factor of energy of ablation in degree 4 was significantly higher than those in degree 1, 2 and 3 blood supply (P < 0.05). It exhibit the positive relationship between blood supply and factor of energy of ablation (r = 0.354, P < 0.01). (3) Score of pain and adverse effect: nearly 85% (120/142) patients could tolerate this treatment very well. Those scores of pain were in range of 0 to 4. All patients did not extend their hospitalization and C to F of

  3. Using Doppler shift induced by Galvanometric mirror scanning to reach shot noise limit with laser optical feedback imaging setup.

    PubMed

    Jacquin, O; Lacot, E; Hugon, O; Guillet de Chatelus, H

    2015-03-10

    This paper proposes what we believe is a new method to remove the contribution of parasitic reflections in the images of the laser optical feedback imaging (LOFI) technique. This simple method allows us to extend the LOFI technique to long-distance applications, as imaging through a fog or a smoke. The LOFI technique is an ultrasensitive imaging technique that is interesting for imaging objects through a scattering medium. However, the LOFI sensitivity can be dramatically limited by parasitic optical feedback occurring in the experimental setup. In previous papers [Appl. Opt.48, 64 (2009)10.1364/AO.48.000064APOPAI1559-128X, Opt. Lett.37, 2514 (2012)10.1364/OL.37.002514OPLEDP0146-9592], we already have proposed methods to filter a parasitic optical feedback, but they are not well suited to metric working distances. This new method uses a Doppler frequency shift induced by the moving mirror used to scan the object to be imaged. Using this Doppler frequency shift, we can distinguish the photons reflected by the target and the parasitic photons reflected by the optical components in the experimental setup. In this paper, we demonstrated theoretically and experimentally the possibility to filter the parasitic reflection in LOFI images using the Doppler frequency shift. This method significantly improves the signal-to-noise ratio by a factor 15 and we can obtain a shot noise limited image through a scattering medium of an object at 3 m from the detector.

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

    PubMed

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

    2014-12-01

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

  5. [Transfontanellar Doppler ultrasound measurement of cerebral blood velocity before and after surgical treatment of hydrocephalus].

    PubMed

    de Assis, M C; Machado, H R

    1999-09-01

    Twenty-seven children with hydrocephalus of different etiologies diagnosed by clinical examination, neurosonography and computerized brain tomography were submitted to transfontanellar US-Doppler evaluation for measurement of blood flow velocity and for the calculation of resistance index (RI) in the anterior and middle cerebral arteries and internal carotids. All children were submitted to evaluation before surgery and on the 1st, 30th and 60th postoperative days. We conclude that neurosonography and US-Doppler technique is useful for determination of hydrocephalus, indication and control of cerebrospinal fluid shunts and monitoring of changes in RI, comparing data obtained immediately before and after surgery and during the late postoperative period. The results obtained when comparing the RI values for the various arteries during the different stages of the study also permitted us to conclude that the anterior cerebral arteries are representative of the maximal alterations that occur in cerebral vascular resistance in pediatric patients with hydrocephalus.

  6. C-scan transmission ultrasound based on a hybrid microelectronic sensor array and its physical performance

    NASA Astrophysics Data System (ADS)

    Lo, Shih-Chung B.; Rich, David; Lasser, Marvin E.; Kula, John; Zhao, Hui; Lasser, Bob; Freedman, Matthew T.

    2001-05-01

    A C-scan through-transmission ultrasound system has been constructed based on a patented hybrid microelectronic array that is capable of generating ultrasound images with fluoroscopic presentation. To generate real-time images, ultrasound is introduced into the object under study with a large unfocused plane wave source. The resultant pressure wave strikes the object and is attenuated and scattered. The device detects scattered as well as attenuated ultrasound energy which allows the use of an acoustic lens to focus on detected energy from an object plane. The acoustic lens collects the transmitted energy and focuses it onto the ultrasound sensitive array. The array is made up to two components, a silicon detector/readout array and a piezoelectric material that is deposited onto the array through semiconductor processing. The array is 1 cm on a side consisting of 128x128 pixel elements with 85micrometers pixel spacing. The energy that strikes the piezoelectric material is converted to an analog voltage that is digitized and processed by low cost commercial video electronics. The images generated by the device appear with no speckle artifact with fluoroscopy-like presentation. The images show no obvious geometrical distortion. The experimental results indicated that the system has a spatial resolution of 0.32 mm. It can resolve 3mm objects with low differential contrast and an attenuation coefficient difference less than 0.07 dB/cm/MHz. Phase contrast of the objects are also clearly measurable. A presentation of a C- scan image guided breast biopsy was demonstrated. In addition, punctured needle tracks in a tumor was clearly observed. This implies the potential of observing the spiculation of masses in vivo.

  7. [Doppler ultrasound assisted hemorrhoid artery ligation. A new therapy in symptomatic hemorrhoids].

    PubMed

    Arnold, S; Antonietti, E; Rollinger, G; Scheyer, M

    2002-03-01

    In 1995, Morinaga et al. (Japan) reported on a new technique in the treatment of hemorrhoids. We report the results of our first 105 patients thus treated. By a specially designed proctoscope coupled with a Doppler transducer, the hemorrhoidal arteries are looked for and ligated. All stages of hemorrhoid were treated. This method is painless, successful, and has a low rate of complications. It is for outpatients and is an alternative to all other methods in the treatment of hemorrhoids.

  8. Understanding quantification of microvascularity with high-frequency power Doppler ultrasound

    NASA Astrophysics Data System (ADS)

    Pinter, Stephen Z.; Lacefield, James C.

    2009-02-01

    High-frequency power Doppler imaging of angiogenesis can be challenging given the presence of small blood vessels and slow flow velocities. In the presence of substantial Doppler artifacts such as false-positive color pixels or undetected vessels, color pixel density (CPD) and related vascularity metrics do not provide accurate estimates of vascular volume fraction. As a step towards improved microvascular quantification, flow-phantom experiments were performed to establish relationships between CPD and wall filter cut-off velocity for various combinations of vessel size (160, 200, 250, 300, and 360 μm), flow velocity (4, 3, 2, 1, and 0.5 mm/s), and transducer frequency (30 and 40 MHz). Three distinct regions were observed in plots of CPD versus wall filter cut-off velocity: overestimation of CPD at low cut-offs, underestimation of CPD at high cut-offs, and a plateau at intermediate cut-offs. The CPD at the plateau closely matched the phantom's actual vascular volume fraction. The length of the plateau corresponded with the flow-detection performance of the Doppler system, which was assessed using receiver operating characteristic analysis. Color pixel density versus wall filter cut-off curves from analogous in vivo experiments exhibited the same shape, including a distinct CPD plateau. The similar shape of the flow-phantom and in vivo curves suggests that the presence of a plateau can be used to identify the best-estimate CPD value in an in vivo experiment. The ability to identify the best CPD estimate is expected to improve quantification of angiogenesis and anti-angiogenic treatment responses with power Doppler.

  9. Modern spectral analysis techniques for blood flow velocity and spectral measurements with pulsed Doppler ultrasound.

    PubMed

    David, J Y; Jones, S A; Giddens, D P

    1991-06-01

    Four spectral analysis techniques were applied to pulsed Doppler ultrasonic quadrature signals to compare the relative merits of each technique for estimation of flow velocity and Doppler spectra. The four techniques were 1) the fast Fourier transform method, 2) the maximum likelihood method, 3) the Burg autoregressive algorithm, and 4) the modified covariance approach to autoregressive modeling. Both simulated signals and signals obtained from an in vitro flow system were studied. Optimal parameter values (e.g., model orders) were determined for each method, and the effects of signal-to-noise ratio and signal bandwidth were investigated. The modern spectral analysis techniques were shown to be superior to Fourier techniques in most circumstances, provided the model order was chosen appropriately. Robustness considerations tended to recommend the maximum likelihood method for both velocity and spectral estimation. Despite the restrictions of steady laminar flow, the results provide important basic information concerning the applicability of modern spectral analysis techniques to Doppler ultrasonic evaluation of arterial disease.

  10. An index of healing in below-knee amputation: leg blood pressure by Doppler ultrasound.

    PubMed

    Barnes, R W; Shanik, G D; Slaymaker, E E

    1976-01-01

    Preoperative Doppler ultrasonic assessment of below-knee (BK) arterial signals and systolic blood pressures was performed on 50 patients undergoing 53 BK amputations for advanced ischemia. No patient was excluded from initial BK amputation unless gangrene at that level or severe joint contracture was present. Failure of healing of the BK amputation occurred in all five limbs with an undetectable Doppler arterial signal (and thus pressure) below the knee. Failure of amputation occurred in four of 16 limbs with detectable arterial signals and BK pressures less than 70 mm. Hg. Healing occurred in all 32 limbs with BK pressures greater than 70 mm. Hg. The differences in healing between these three groups are highly significant (p less than 0.005). This study suggests that Doppler ultrasonic assessment of BK arterial signals and pressures may be a simple hemodynamic correlate of healing of a BK amputation. Absence of a detectable arterial signal below the knee may be an indication for initial above-knee (AK) amputation in advanced ischemia.

  11. Detection of Breast Microcalcifications Under Ultrasound Using Power Doppler and Acoustic Resonance Imaging

    DTIC Science & Technology

    2003-07-01

    2241 010511 imaging, including magnetic resonance Radiology 2002; 224:265-269 Calcium carbonate particles embed- imaging, scintigraphy , and...characterize calcifications. digitized M-mode images: gestational dif- ways feasible because calcifications can- ferences of fetal lung . Ultrasound Med Biol

  12. Stratospheric temperature measurement with scanning Fabry-Perot interferometer for wind retrieval from mobile Rayleigh Doppler lidar.

    PubMed

    Xia, Haiyun; Dou, Xiankang; Shangguan, Mingjia; Zhao, Ruocan; Sun, Dongsong; Wang, Chong; Qiu, Jiawei; Shu, Zhifeng; Xue, Xianghui; Han, Yuli; Han, Yan

    2014-09-08

    Temperature detection remains challenging in the low stratosphere, where the Rayleigh integration lidar is perturbed by aerosol contamination and ozone absorption while the rotational Raman lidar is suffered from its low scattering cross section. To correct the impacts of temperature on the Rayleigh Doppler lidar, a high spectral resolution lidar (HSRL) based on cavity scanning Fabry-Perot Interferometer (FPI) is developed. By considering the effect of the laser spectral width, Doppler broadening of the molecular backscatter, divergence of the light beam and mirror defects of the FPI, a well-behaved transmission function is proved to show the principle of HSRL in detail. Analysis of the statistical error of the HSRL is carried out in the data processing. A temperature lidar using both HSRL and Rayleigh integration techniques is incorporated into the Rayleigh Doppler wind lidar. Simultaneous wind and temperature detection is carried out based on the combined system at Delhi (37.371°N, 97.374°E; 2850 m above the sea level) in Qinghai province, China. Lower Stratosphere temperature has been measured using HSRL between 18 and 50 km with temporal resolution of 2000 seconds. The statistical error of the derived temperatures is between 0.2 and 9.2 K. The temperature profile retrieved from the HSRL and wind profile from the Rayleigh Doppler lidar show good agreement with the radiosonde data. Specifically, the max temperature deviation between the HSRL and radiosonde is 4.7 K from 18 km to 36 km, and it is 2.7 K between the HSRL and Rayleigh integration lidar from 27 km to 34 km.

  13. Abdominal Ultrasound

    MedlinePlus

    ... Ultrasound - Abdomen Ultrasound imaging of the abdomen uses sound waves to produce pictures of the structures within ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  14. Hip Ultrasound

    MedlinePlus

    ... Index A-Z Hip Ultrasound Hip ultrasound uses sound waves to produce pictures of muscles, tendons, ligaments, ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  15. Ultrasound - Breast

    MedlinePlus

    ... Ultrasound - Breast Ultrasound imaging of the breast uses sound waves to produce pictures of the internal structures ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  16. Obstetrical Ultrasound

    MedlinePlus

    ... Index A-Z Obstetric Ultrasound Obstetric ultrasound uses sound waves to produce pictures of a baby (embryo ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  17. Effects of Position and Operator on High-frequency Ultrasound Scan Quality

    PubMed Central

    Burk, Ruth S.; Parker, Angela; Sievers, Lisa; Rooney, Melissa B.; Pepperl, Anathea; Schubert, Christine M.; Grap, Mary Jo

    2015-01-01

    Objectives High-frequency ultrasound may evaluate those at risk for pressure ulcers. Images may be obtained by clinicians with limited training. The prone position is recommended for obtaining sacral scans but may not be feasible in the critically ill. This study investigated image quality using multiple operators and a variety of patient positions. Research Methodology Sacral scans were performed in three randomized positions in 50 volunteers by three different investigators using a 20 MHz ultrasound system. General linear models and ANOVA random effects models were used to examine the effects of operator and position on image quality rating, and measures of dermal thickness, and dermal density. Results The best scan for each position and operator was used for analysis (N=447 images). Image rating varied by operator (p=0.0004), although mean ratings were 3.5 or above for all operators. Dermal thickness was less for the prone position than in 90° or 60° side-lying positions (p=0.0137, p=0.0003). Dermal density was lower for the prone position than for the 90° or 60° positions (p<0.0001 for both). Conclusions These data show that overall scan quality was acceptable in all positions with all operators. However, differences were found between side-lying positions and the prone for dermal thickness and dermal density measures. PMID:25636253

  18. Ultrasound -- Pelvis

    MedlinePlus Videos and Cool Tools

    ... needles are used to extract a sample of cells from organs for laboratory testing. Doppler ultrasound images ... ultrasound, measures the direction and speed of blood cells as they move through vessels. The movement of ...

  19. Stimulated acoustic emission detected by transcranial color doppler ultrasound : a contrast-specific phenomenon useful for the detection of cerebral tissue perfusion.

    PubMed

    Pohl, C; Tiemann, K; Schlosser, T; Becher, H

    2000-07-01

    Experimental and clinical data suggest that insonation of echo-contrast agents with high acoustical power produces disintegration of microbubbles, resulting in a pseudo-Doppler phenomenon called stimulated acoustic emission (SAE). The purpose of this study was to investigate whether SAE might be detected by transcranial color Doppler imaging and whether these signals might be used for cerebral tissue perfusion measurements. Nonmoving microbubbles (SHU 563 A) were insonated in vitro through the temporal parts of a human cadaver skull, and contrast signals were detected by velocity-coded color Doppler and power Doppler recordings. Transcranial color as well as power Doppler investigations were performed in 10 healthy volunteers with the echo-contrast agent Levovist (SHU 508 A). Color Doppler signals indicating SAE were observed in vitro and in transcranial human investigations. These signals were characterized by a mosaic of color Doppler pixels ranging over the full color scale. Apparent velocity information and spatial distribution of SAE signals changed from image frame to image frame. In the experimental model, the intensity of SAE signals decreased exponentially over time. With an increase of acoustic power, there was a significant increase of the maximum signal intensity (P<0.01) and a significantly shortened signal duration (P<0.01), consistent with stronger and more rapid disintegration. In humans, SAE signals were clearly detected in cerebral tissue regions. The intensity of SAE signals in those regions (eg, temporal cortex, 3.7+/-1.2 dB) was approximately 8 times lower than the signal enhancement in the major cerebral arteries (eg, in the MCA, 29.5+/-5.6). Echo-contrast specific color Doppler signals known as SAE are detectable by transcranial color and power Doppler sonography. Signals due to SAE might represent tissue perfusion, thereby providing a method for imaging flow with transcranial ultrasound.

  20. Turbulence in wind turbine wakes under different atmospheric conditions from static and scanning Doppler LiDARs

    NASA Astrophysics Data System (ADS)

    Kumer, Valerie; Reuder, Joachim

    2016-04-01

    Wake characteristics are of great importance for wind park performances and turbine loads. Wind tunnel experiments helped to validate wake model simulations under neutral atmospheric conditions. However, recent studies show strongest wake characteristics and power losses in stable atmospheric conditions. Considering all three occurring atmospheric conditions this study presents a turbulence analysis of wind turbine wake flows measured by static and scanning Doppler LiDARs at the coast of the Netherlands. We use data collected by three Windcubes v1, a scanning Windcube 100S and sonic anemometers during the Wind Turbine Wake Experiment - Wieringermeer (WINTWEX-W). Turbulence parameters such as Turbulence Intensity (TI) and turbulent kinetic energy (TKE) are retrieved from the collected raw data. Results show highest turbulence on the flanks of the wake where strong wind shear dominates. On average the spatial turbulence distribution becomes more homogeneous with conical areas of enhanced TI. Highest turbulence and strongest wind deficits occur during stable weather conditions. Despite the ongoing research on the reliability of turbulence retrievals of Doppler LiDAR data, the results are consistent with sonic anemometer measurements and show promising opportunities for a qualitative study of wake characteristics such as wake strength and wake peak frequencies.

  1. New applications of scanning laser Doppler vibrometry (SLDV) to nondestructive diagnosis of artwork: mosaics, ceramics, inlaid wood, and easel painting

    NASA Astrophysics Data System (ADS)

    Castellini, Paolo; Esposito, Enrico; Marchetti, Barbara; Paone, Nicola; Tomasini, Enrico P.

    2001-10-01

    During the last years the growing importance of the correct determination of the state of conservation of artworks has been stated by all personalities in care of Cultural Heritage. There exist many analytical methodologies and techniques to individuate the physical and chemical characteristics of artworks, but at present their structural diagnostics mainly rely on the expertise of the restorer and the typical diagnostic process is accomplished mainly through manual and visual inspection of the object surface. The basic idea behind the proposed technique is to substitute human senses with measurement instruments: surfaces are very slightly vibrated by mechanical actuators, while a laser Doppler vibrometer scans the objects measuring surface velocity and producing 2D or 3D maps. Where a defect occurs velocity is higher than neighboring areas so defects can be easily spotted. Laser vibrometers also identify structural resonance frequencies thus leading to a complete characterization of defects. This work will present the most recent results coming out of the application of Scanning Laser Doppler Vibrometers (SLDV) to different types of artworks: mosaics, ceramics, inlaid wood and easel painting. Real artworks and samples realized on purpose have been studied using the proposed technique and different measuring issues resulting from each artwork category will be described.

  2. Mathematical modelling of the human foetal cardiovascular system based on Doppler ultrasound data.

    PubMed

    Pennati, G; Bellotti, M; Fumero, R

    1997-06-01

    A lumped parameter model of the human foetal circulation primarily based on blood velocity data derived from the Doppler analysis was developed in this study. It consists of two major parts, the heart and the foetal vascular circulation. The heart model accounts for both ventricular and atrial contractility. The circulation was divided into 19 compliant vascular compartments in order to describe all of the clinically monitored sites. The model parameters refer to the final gestation period and were derived either from literature on foetal sheep circulation or from anatomical dimension monitoring of the human foetus. No control mechanism is incorporated into the model. The model was validated by comparing several index values of simulated velocity curves to those of the experimental Doppler waveforms. The mean and maximum percentual errors in the estimation of the experimental results by the model are 7.7% and 20.1%, respectively. Velocity and pressure tracings of the foetal circulation were investigated, as well as regional blood flow rate distribution.

  3. Automatic transperineal ultrasound probe positioning based on CT scan for image guided radiotherapy

    NASA Astrophysics Data System (ADS)

    Camps, S. M.; Verhaegen, F.; Paiva Fonesca, G.; de With, P. H. N.; Fontanarosa, D.

    2017-03-01

    Image interpretation is crucial during ultrasound image acquisition. A skilled operator is typically needed to verify if the correct anatomical structures are all visualized and with sufficient quality. The need for this operator is one of the major reasons why presently ultrasound is not widely used in radiotherapy workflows. To solve this issue, we introduce an algorithm that uses anatomical information derived from a CT scan to automatically provide the operator with a patient-specific ultrasound probe setup. The first application we investigated, for its relevance to radiotherapy, is 4D transperineal ultrasound image acquisition for prostate cancer patients. As initial test, the algorithm was applied on a CIRS multi-modality pelvic phantom. Probe setups were calculated in order to allow visualization of the prostate and adjacent edges of bladder and rectum, as clinically required. Five of the proposed setups were reproduced using a precision robotic arm and ultrasound volumes were acquired. A gel-filled probe cover was used to ensure proper acoustic coupling, while taking into account possible tilted positions of the probe with respect to the flat phantom surface. Visual inspection of the acquired volumes revealed that clinical requirements were fulfilled. Preliminary quantitative evaluation was also performed. The mean absolute distance (MAD) was calculated between actual anatomical structure positions and positions predicted by the CT-based algorithm. This resulted in a MAD of (2.8±0.4) mm for prostate, (2.5±0.6) mm for bladder and (2.8±0.6) mm for rectum. These results show that no significant systematic errors due to e.g. probe misplacement were introduced.

  4. A scanning laser source and a microcantilever ultrasound receiver for detection of surface flaws in microdevices

    NASA Astrophysics Data System (ADS)

    Sohn, Younghoon; Krishnaswamy, Sridhar

    2005-05-01

    In recent work at Northwestern University, we have shown that near-field scattering of ultrasound generated by a Scanning Laser Source (SLS) can be used to effectively identify surface flaws in macroscale structures. In past work, the laser ultrasound source was in the near-field of a scatterer and a piezoelectric detector was used to measure the ultrasound in the far field. It was observed that distinct variations are observed in the far-field signals as the SLS scans past surface-breaking flaws. These changes were attributed to the near-field scatterer redirecting parts of the ultrasonic beam (which might otherwise have gone into the bulk of the object) towards the far-field detector. We now propose an extension of the SLS approach to map defects in microdevices by bringing both the generator and the receiver to the near-field scattering region of the defects. For the purpose of near-field ultrasound measurement, the receiving transducer has to be made very small as well. To facilitate this, silicon microcantilever probes are fabricated and their acoustical characteristics are first investigated. Silicon cantilevers with tip and chip body are fabricated using isotropic reactive ion etching and anisotropic KOH etching. To characterize the free cantilever vibration, the chip body with the microcantilever is excited by an ultrasonic transducer and a Michelson interferometer is used to monitor the cantilever motion. The fundamental frequency of the microcantilever is measured and compared with analytically calculated fundamental frequency assuming the cross sections of the cantilevers are rectangular. Next, the performance of the fabricated microcantilevers as ultrasound detectors is investigated. The microcantilever is used essentially as a profilometer by contacting it to the specimen surface. Surface and bulk acoustic waves are generated with specific narrowband frequencies and the surface ultrasonic displacements are detected using the microcantilever probe. Next

  5. Is dynamic cerebral autoregulation measurement using transcranial Doppler ultrasound reproducible in the presence of high concentration oxygen and carbon dioxide?

    PubMed

    Minhas, Jatinder S; Syed, Nazia F; Haunton, Victoria J; Panerai, Ronney B; Robinson, Thompson G; Mistri, Amit K

    2016-05-01

    Reliability of cerebral blood flow velocity (CBFV) and dynamic cerebral autoregulation estimates (expressed as autoregulation index: ARI) using spontaneous fluctuations in blood pressure (BP) has been demonstrated. However, reliability during co-administration of O2 and CO2 is unknown. Bilateral CBFV (using transcranial Doppler), BP and RR interval recordings were performed in healthy volunteers (seven males, four females, age: 54  ±  10 years) on two occasions over 9  ±  4 d. Four 5 min recordings were made whilst breathing air (A), then 5%CO2 (C), 80%O2 (O) and mixed O2  +  CO2 (M), in random order. CBFV was recorded; ARI was calculated using transfer function analysis. Precision was quantified as within-visit standard error of measurement (SEM) and the coefficient of variation (CV). CBFV and ARI estimates with A (SEM: 3.85 & 0.87; CV: 7.5% & 17.8%, respectively) were comparable to a previous reproducibility study. The SEM and CV with C and O were similar, though higher values were noted with M; Bland-Altman plots indicated no significant bias across all gases for CBFV and ARI (bias  <0.06 cm s(-1) and  <0.05, respectively). Thus, transcranial-Doppler-ultrasound-estimated CBFV and ARI during inhalation of O2 and CO2 have acceptable levels of reproducibility and can be used to study the effect of these gases on cerebral haemodynamics.

  6. Ischemia-Modified Albumin (IMA): A Novel Marker for Preeclampsia Independent of Uterine Artery Notching Identified by Doppler Ultrasound.

    PubMed

    Doğan, Keziban; Guraslan, Hakan; Çankaya, Atilla; Dağdeviren, Hediye; Ekin, Murat

    2015-11-01

    To determine the predictive value of second trimester serum ischemia-modified albumin (IMA) levels for preeclampsia (PE), small for gestational age (SGA) and gestational diabetes mellitus (GDM). The study was conducted at a tertiary care hospital between May and August 2014. Healthy pregnant women (n = 88) who were screened for fetal anomalies with ultrasound at 20-24 weeks of gestation were included in the study. Doppler measurements of the bilateral uterine arteries were performed in all the patients. Serum samples were obtained for an IMA assay. The maternal serum IMA levels were compared in pregnant women who had normal and abnormal uterine artery Doppler findings, including notching, and also in pregnant women who subsequently developed PE, SGA, and GDM during the follow-up period. Uterine artery notching was not significantly predictive for PE, GDM or SGA (p > 0.05). There was no significant difference between notching of the uterine arteries and serum IMA levels (p > 0.05). Eight pregnant women (9.1%) subsequently developed PE. Serum IMA levels were significantly elevated in patients with PE compared with patients who did not subsequently develop PE (p = 0.002). However, serum IMA levels were not significantly different in patients who subsequently developed SGA and GDM compared with women who did not (p > 0.05). There was no correlation between serum IMA levels and maternal characteristics and laboratory findings. Maternal serum IMA levels at 20-24 weeks' gestation might be a predictive biomarker for PE, independent of notching of the uterine arteries, maternal characteristics and laboratory findings.

  7. Comparison of dynamic contrast enhanced MRI and Doppler ultrasound in the pre-operative assessment of the portal venous system.

    PubMed

    Naik, K S; Ward, J; Irving, H C; Robinson, P J

    1997-01-01

    The purpose of this study was to compare dynamic contrast enhanced MRI (DCEMR) with Doppler ultrasound (US) in the assessment of portal venous anatomy and to analyse the causes of discrepancy. Over a 1 year period, 97 patients undergoing assessment prior to hepatic surgery underwent imaging of the liver and portal venous system using US with colour and spectral Doppler and MRI with axial T2 weighted spin echo (SE) and coronal oblique T1 weighted rapid gradient echo (GRE) imaging before and immediately after bolus injection of Gd-DTPA (0.1 mmol kg-1). When the US and MRI findings were discrepant, the images were reviewed by two observers and compared with surgical findings. US and DCEMR were concordant in 90 patients (portal vein patent in 80, occluded in 10). In three patients with cirrhosis and gross ascites the portal vein was reported as occluded on US and patent on MRI; surgery confirmed the MRI findings. In one patient the portal vein was patient on US but not on MRI, but there was a 3 week interval between the examinations. In three patients the portal vein was patent on US, but MRI detected occlusion of intrahepatic portal vein branches in two, and encasement of an intrahepatic branch in the third case. Spontaneous splenorenal shunts were seen in 15 patients only on MRI; varices were seen in 39 patients on MRI and in 22 patients on US. Both US and DCEMR contribute to the pre-operative assessment of the portal venous system. MRI provides additional information over US in assessing intrahepatic portal branches and detecting varices and splenorenal shunts, and is recommended for all surgical candidates and in patients with abnormal portal venous anatomy and equivocal US findings.

  8. Assessment of cerebral autoregulation with transcranial Doppler sonography in poor bone windows using constant infusion of an ultrasound contrast agent.

    PubMed

    Lorenz, Matthias W; Thoelen, Nina; Loesel, Nadine; Lienerth, Christian; Gonzalez, Marilen; Humpich, Marek; Roelz, Waltraud; Dvorak, Florian; Sitzer, Matthias

    2008-03-01

    Cerebral autoregulation is an important pathophysiological and prognostic parameter for a variety of neurologic conditions. It can be assessed quickly and safely using transcranial Doppler sonography (TCD). In elderly patients, poor insonation conditions decrease the number of examinable patients and can cause a systematic bias in autoregulation parameters. The aim of this study was to investigate whether a constant infusion of an ultrasound contrast agent (Levovist((R))) can counteract these effects. We examined two cohorts of unselected neurologic patients. In 45 patients with good insonation windows (cohort 1), we used a thin aluminium foil between the skin and the TCD probe to artificially decrease the insonation quality. We determined two parameters of cerebral autoregulation (phase difference [PD] and a cross-correlation coefficient [Mx]) in native patients, with aluminium foil and with aluminium foil and a constant infusion of Levovist. In 30 patients with poor insonation windows (cohort 2), we measured the autoregulation twice, with and without an infusion of Levovist, to assess the reproducibility of the autoregulation parameters. In cohort 1, the foil model significantly decreased the Doppler signal quality, i.e., the mean spectrum energy decreased from 33.9 +/- 2.7 dB to 26.3 +/- 2.4 dB (p < 0.001). This introduced a significant bias to all autoregulation parameters (PD: decreased from 38.2 +/- 10.0 degrees to 27.9 +/- 12.5 degrees (p < 0.001); Mx: decreased from 0.308 +/- 0.170 to 0.254 +/- 0.162 (p < 0.01)). Both effects were compensated largely by a constant infusion of Levovist (300 mg/min). In cohort 2, infusion of the contrast agent at the same rate increased insonation quality, too, but to a lesser degree (27.4 +/- 2.4 dB to 32.0 +/- 3.7 dB, p < 0.001). This smaller increase did not cause a significant change in the autoregulation parameters, but the reproducibility of the PD was significantly improved (intraclass coefficient coefficient [ICC] 0

  9. Contrast-enhanced ultrasound in combination with color Doppler ultrasound can improve the diagnostic performance of focal nodular hyperplasia and hepatocellular adenoma.

    PubMed

    Kong, Wen-Tao; Wang, Wen-Ping; Huang, Bei-Jian; Ding, Hong; Mao, Feng; Si, Qin

    2015-04-01

    The aim of our study was to evaluate the value of combining color Doppler ultrasound (CDUS) with contrast-enhanced ultrasound (CEUS) in identifying and comparing features of focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA). Thirty-eight patients with FNH (n = 28) or HCA (n = 10), whose diagnoses were later confirmed by pathology, were examined with conventional ultrasonography and CEUS between 2010 and 2013. Two doctors blinded to the pathology results independently reviewed the conventional ultrasound and CEUS images and then reached a consensus through discussion. The following parameters evaluated for all lesions included vascularity pattern on CDUS or CEUS, enhancement characteristics on CEUS and the presence of a central scar. Statistical analysis was performed with the independent sample t-test and Fisher exact test. On CDUS, FNH was characterized by the presence of abundant blood flow signals exhibiting dendritic (53.6%, 15/28) and spoke-wheel (28.6%, 8/28) patterns, whereas blood flow signal of HCA was slightly less than FNH and often showed subcapsular short rod-like (50%, 5/10) appearance. On CEUS, the most common arterial enhancement pattern was centrifugal or homogeneous enhancement in FNH (both, 12/28, 42.9%) and homogeneous enhancement in HCA (6/10, 60%). Spoke-wheel arteries, feeding artery and central scar were detected in 5 (17.9%), 8 (28.6%) and 5 (17.9%) of 28 FNHs. Hypo-echogenic pattern during delayed phase was more common in HCA (60%, 6/10) than in FNH (3/28, 10.7%) (p = 0.010). A total of 25 (25/38, 65.8%) lesions were correctly assessed using CDUS in combination with CEUS, whereas the number decreased to 15 (15/38, 39.5%) when CDUS was used alone (p = 0.038). The areas under the ROC curves before and after CEUS administration were 0.768 and 0.879, respectively. In conclusion, CEUS in combination with CDUS improve the diagnostic performance of FNH and HCA. Blood signal of HCA was less than FNH on CDUS. The differences of

  10. Semen quality, testicular B-mode and Doppler ultrasound, and serum testosterone concentrations in dogs with established infertility.

    PubMed

    de Souza, Mírley Barbosa; England, Gary C W; Mota Filho, Antônio Cavalcante; Ackermann, Camila Louise; Sousa, Carmen Vládia Soares; de Carvalho, Gabriela Guedelha; Silva, Herlon Victor Rodrigues; Pinto, José Nicodemos; Linhares, Jussiara Candeira Spíndola; Oba, Eunice; da Silva, Lúcia Daniel Machado

    2015-09-15

    Retrospective examination of breeding records enabled the identification of 10 dogs of normal fertility and 10 dogs with established infertility of at least 12 months of duration. Comparisons of testicular palpation, semen evaluation, testicular ultrasound examination, Doppler ultrasound measurement of testicular artery blood flow, and measurement of serum testosterone concentration were made between the two groups over weekly examinations performed on three occasions. There were no differences in testicular volume (cm(3)) between the two groups (fertile right testis = 10.77 ± 1.66; fertile left testis = 12.17 ± 2.22); (infertile right testis = 10.25 ± 3.33; infertile left testis = 11.37 ± 3.30), although the infertile dogs all had subjectively softer testes compared with the fertile dogs. Infertile dogs were either azoospermic or when they ejaculated, they had lower sperm concentration, sperm motility, and percentage of morphologically normal spermatozoa than fertile dogs. Furthermore, infertile dogs had reduced sperm membrane integrity measured via the hypoosmotic swelling test. Infertile dogs had significantly lower basal serum testosterone concentrations (1.40 ± 0.62 ng/mL) than fertile dogs (1.81 ± 0.87 ng/mL; P < 0.05). There were subjective differences in testicular echogenicity in some of the infertile dogs, and important differences in testicular artery blood flow with lower peak systolic and end-diastolic velocities measured in the distal supratesticular artery, marginal testicular artery, and intratesticular artery of infertile dogs (P < 0.05). Notably, resistance index and pulsatility index did not differ between infertile and fertile dogs. These findings report important differences between infertile and fertile dogs which may be detected within an expanded breeding soundness examination.

  11. Practical Use of Ultrasound Scan in Small Ruminant Medicine and Surgery.

    PubMed

    Scott, Phil

    2016-03-01

    Modern portable ultrasound scan machines provide the veterinary clinician with an inexpensive and noninvasive method to further examine sheep on farms, which should take no more than 5 minutes with the results available immediately. Repeat examinations allow monitoring of the disease process and assessment of therapy. 5 MHz linear array scanners can be used for most organs except the heart and right kidney. Transthoracic ultrasonography is particularly useful for critical evaluation of lung and pleural pathologies. Transabdominal ultrasonographic examination can readily identify distended urinary bladder and advanced hydronephrosis. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Ultrasound resistive index, power Doppler, and clinical parameters in established rheumatoid arthritis.

    PubMed

    Bisi, Melissa Cláudia; do Prado, Aline Defaveri; Piovesan, Deise Marcela; Bredemeier, Markus; da Silveira, Inês Guimarães; de Mendonça, José Alexandre; Staub, Henrique Luiz

    2017-04-01

    Ultrasonography (US) is a useful tool for the evaluation of sinovial vascularization and proliferation in rheumatoid arthritis (RA). Accordingly, resistive index (RI) on spectral Doppler (sD) US provides a quantitative analysis of vascular inflammation, but its utility in the evaluation of RA activity has not been established. Our objective was to determine the association of RI with other US parameters of synovitis and with clinical disease activity in established RA. Patients with positive power Doppler (pD) were included in a prospective cross-sectional study. Disease activity and disability were evaluated using the Disease Activity Score in 28-joints (DAS28) and Health Assessment Questionnaire (HAQ), respectively. Gray scale (GS) synovitis, pD, and sD analyses were performed by one of two examiners in wrists and the second and third metacarpophalangeal and proximal interphalangeal joints. The 10-joint GS and 10-joint pD scores and mean RI were then calculated. Weighted kappa (WK) values were employed to assess interobserver reability, and correlations were tested using the Spearman coefficient. Ninety-five RA patients (median duration of disease of 7 years and mean DAS28 of 4.32 ± 1.66) were included. WK values in real-time US were 0.77 for synovitis, 0.87 for pD, and 0.68 for RI. There were no significant correlations of RI with 10-joint GS, 10-joint pD, DAS28, joint counts, or HAQ (P > 0.10 for all tests). Patients in remission had a mean RI similar to those with high disease activity (0.62 ± 0.10, n = 15 versus 0.63 ± 0.13, n = 34, respectively). The addition of the RI score did not seem to improve US performance in patients with established RA.

  13. Can simple clinical features be used to identify patients with severe carotid stenosis on Doppler ultrasound?

    PubMed Central

    Mead, G.; Wardlaw, J.; Lewis, S.; McDowall, M.; Dennis, M.

    1999-01-01

    OBJECTIVES—Carotid endarterectomy reduces the risk of stroke in symptomatic patients with severe ipsilateral carotid stenosis. Symptomatic patients should therefore undergo carotid Doppler imaging, but in some centres access to imaging is limited. It was therefore investigated whether simple clinical features alone or in combination could be used to identify patients with severe carotid stenosis, so that they could be referred preferentially for carotid imaging.
METHODS—1041 patients with acute stroke, cerebral or retinal transient ischaemic attacks, and retinal strokes admitted to Western General Hospital or seen in neurovascular clinics were assessed by a stroke physician. Their carotid arteries were investigated using colour Doppler imaging by a consultant neuroradiologist. Patients with primary intracerebral haemorrhage, total anterior circulation strokes, posterior circulation strokes, or posterior circulation transient ischaemic attacks were excluded because carotid surgery would be inappropriate.
RESULTS—726 patients were used in the analysis. Stepwise logistic regression showed that there were significant positive associations between severe carotid stenosis and an ipsilateral bruit, diabetes mellitus, and previous transient ischaemic attacks; and a negative association with lacunar events. The strategy with the highest specificity (97%) was "any three of these four features" but sensitivity was only 17%. The strategy with the highest sensitivity (99%) was to use one or more of the four features, but specificity was only 22%.
CONCLUSION—None of the strategies identified all patients with severe carotid stenosis with a reasonable specificity. When access to carotid imaging is severely limited, simple clinical features are of some use in prioritising patients for imaging, but access to carotid imaging should be improved. 

 PMID:9886444

  14. Transcranial measurement of blood velocities in the basal cerebral arteries using pulsed Doppler ultrasound: a method of assessing the Circle of Willis.

    PubMed

    Padayachee, T S; Kirkham, F J; Lewis, R R; Gillard, J; Hutchinson, M C; Gosling, R G

    1986-01-01

    Transcranial pulsed Doppler ultrasound and spectral analysis were used for detection of blood velocities in the basal cerebral arteries. The Doppler transducer was placed superior to the zygomatic arch and during insonation of the middle cerebral artery care was taken to obtain maximum Doppler-shift frequency signals since this allowed a small angle between the ultrasound beam and this artery. Doppler signals were obtained from the middle, anterior, and posterior cerebral arteries in 20 volunteers with the average depth of the Doppler gate at 4.9 (4.6-5.2 cm), 5.2 (4.9-5.4 cm), and 6.3 cm (6.0-6.9 cm), respectively. These measurements were in agreement with those obtained for 15 cadaver studies, in whom the distance from the proposed site of the Doppler transducer to each basal cerebral artery was measured as 4.7 +/- 0.6, 5.3 +/- 0.5, and 5.9 +/- 0.9 cm, respectively. The reproducibility of middle cerebral artery blood velocity values was tested in seven subjects and showed a variation of not more than 8% in any individual. The method was used in combination with common carotid compression to assess four patients who had occlusive extracranial carotid disease; in three the disease was more severe on one side and reversal of blood flow in the proximal ipsilateral anterior cerebral artery was demonstrated, consistent with cross flow from the contralateral side via the anterior communicating artery of the Circle of Willis. In the fourth patient augmentation of posterior cerebral artery blood velocities during common carotid compression indicated the major collateral source was from the vertebrobasilar system.

  15. 5D interactive real time Doppler ultrasound visualization of the heart

    NASA Astrophysics Data System (ADS)

    Heid, Volker; Evers, Harald; Henn, Christian; Glombitza, Gerald; Meinzer, Hans-Peter

    2000-04-01

    Heart valve insufficiencies can optimally be assessed using transesophageal, triggered, three-dimensional ultrasound imaging. The dynamic ultrasound data contain morphological as well as functional components which are recorded and displayed simultaneously. It allows the visualization of intracardiac motion which is an important parameter to detect abnormal flow caused by defect valves. A realtime reconstruction is desired to get a spatial impression on the one hand and to interactively clip parts of the volume on the other hand. OpenGL Volumizer is used for visualization. Scalability of the visualization was tested with respect to different workstations and graphics resources using a Multipipe Utility library (MPU). The combination of both APIs enables a visualization of volumetric and functional data with frame rates up to 10 frames per second. By using the proposed method, it is possible to visualize the jet in the original color-coding which is employed during a conventional two- dimensional examination for displaying the velocity values. A good scalability from low cost up to high end graphic workstations is given by the use of the MPU. The quality of the resulting 3D images allows exact differentiation of heart valve insufficiencies to support the diagnostic procedure.

  16. A-scan ultrasound system for real-time puncture safety assessment during percutaneous nephrolithotomy

    NASA Astrophysics Data System (ADS)

    Rodrigues, Pedro L.; Rodrigues, Nuno F.; Fonseca, Jaime C.; von Krüger, M. A.; Pereira, W. C. A.; Vilaça, João. L.

    2015-03-01

    Background: Kidney stone is a major universal health problem, affecting 10% of the population worldwide. Percutaneous nephrolithotomy is a first-line and established procedure for disintegration and removal of renal stones. Its surgical success depends on the precise needle puncture of renal calyces, which remains the most challenging task for surgeons. This work describes and tests a new ultrasound based system to alert the surgeon when undesirable anatomical structures are in between the puncture path defined through a tracked needle. Methods: Two circular ultrasound transducers were built with a single 3.3-MHz piezoelectric ceramic PZT SN8, 25.4 mm of radius and resin-epoxy matching and backing layers. One matching layer was designed with a concave curvature to work as an acoustic lens with long focusing. The A-scan signals were filtered and processed to automatically detect reflected echoes. Results: The transducers were mapped in water tank and tested in a study involving 45 phantoms. Each phantom mimics different needle insertion trajectories with a percutaneous path length between 80 and 150 mm. Results showed that the beam cross-sectional area oscillates around the ceramics radius and it was possible to automatically detect echo signals in phantoms with length higher than 80 mm. Conclusions: This new solution may alert the surgeon about anatomical tissues changes during needle insertion, which may decrease the need of X-Ray radiation exposure and ultrasound image evaluation during percutaneous puncture.

  17. A beam-scan type laser Doppler velocimeter for simultaneous and continuous measurement of velocity profiles

    NASA Astrophysics Data System (ADS)

    Hino, M.; Nadaoka, K.; Kobayashi, T.; Sato, Y.; Muramoto, T.

    A beam-scan-type LDV (SLV) with high spatial resolving power has been developed for the continuous measurement of nearly simultaneous velocity profiles in the cross sections of various flows. The SLV consists of a forward-scatter LDV and a beam-scan unit, using a reversed-scan method, capable of high-speed scanning of the measuring volume. An autofocusing device using an image sensor is employed to simplify the alignment of the receiving optics needed to match the transmitting optics. The SLV performance was validated by comparison of experimental results (for a wake flow of a circular cylinder, a reciprocally oscillatory flow, and a Karman vortex street flow) with flow visualization and computational results.

  18. Assessment of flow distribution in the mouse fetal circulation at late gestation by high-frequency Doppler ultrasound.

    PubMed

    Zhou, Yu-Qing; Cahill, Lindsay S; Wong, Michael D; Seed, Mike; Macgowan, Christopher K; Sled, John G

    2014-08-15

    This study used high-frequency ultrasound to evaluate the flow distribution in the mouse fetal circulation at late gestation. We studied 12 fetuses (embryonic day 17.5) from 12 pregnant CD1 mice with 40 MHz ultrasound to assess the flow in 11 vessels based on Doppler measurements of blood velocity and M-mode measurements of diameter. Specifically, the intrahepatic umbilical vein (UVIH), ductus venosus (DV), foramen ovale (FO), ascending aorta (AA), main pulmonary artery (MPA), ductus arteriosus (DA), descending thoracic aorta (DTA), common carotid artery (CCA), inferior vena cava (IVC), and right and left superior vena cavae (RSVC, LSVC) were examined, and anatomically confirmed by micro-CT. The mouse fetal circulatory system was found to be similar to that of the humans in terms of the major circuit and three shunts, but characterized by bilateral superior vena cavae and a single umbilical artery. The combined cardiac output (CCO) was 1.22 ± 0.05 ml/min, with the left ventricle (flow in AA) contributing 47.8 ± 2.3% and the right ventricle (flow in MPA) 52.2 ± 2.3%. Relative to the CCO, the flow percentages were 13.6 ± 1.0% for the UVIH, 10.4 ± 1.1% for the DV, 35.6 ± 2.4% for the DA, 41.9 ± 2.6% for the DTA, 3.8 ± 0.3% for the CCA, 29.5 ± 2.2% for the IVC, 12.7 ± 1.0% for the RSVC, and 9.9 ± 0.9% for the LSVC. The calculated flow percentage was 16.6 ± 3.4% for the pulmonary circulation and 31.2 ± 5.3% for the FO. In conclusion, the flow in mouse fetal circulation can be comprehensively evaluated with ultrasound. The baseline data of the flow distribution in normal mouse fetus serve as the reference range for future studies. Copyright © 2014 the American Physiological Society.

  19. Monostatic coaxial 1.5 μm laser Doppler velocimeter using a scanning Fabry-Perot interferometer.

    PubMed

    Rodrigo, Peter John; Pedersen, Christian

    2013-09-09

    We present a laser Doppler velocimeter (LDV) in monostatic coaxial arrangement consisting of off-the-shelf telecom-grade components: a single frequency laser (wavelength λ = 1.5 μm) and a high-finesse scanning Fabry-Perot interferometer (sFPI). In contrast to previous 1.5 μm LDV systems based on heterodyne detection, our sFPI-LDV has the advantages of having large remote sensing range not limited by laser coherence, high velocity dynamic range not limited by detector bandwidth and inherent sign discrimination of Doppler shift. The more optically efficient coaxial arrangement where transmitter and receiver optics share a common axis reduces the number of components and greatly simplifies the optical alignment. However, the sensitivity to unwanted backreflections is increased. To circumvent this problem, we employ a custom optical circulator design which compared to commercial fiber-optic circulator achieves ~40 dB reduction in strength of unwanted reflections (i.e. leakage) while maintaining high optical efficiency. Experiments with a solid target demonstrate the performance of the sFPI-LDV system with high sensitivity down to pW level at present update rates up to 10 Hz.

  20. Hemodynamic effect of percutaneous transluminal angioplasty for lower limb atherosclerosis. A study based on pulsed Doppler ultrasound flowmetry.

    PubMed

    Jørgensen, J J; Stranden, E; Gjølberg, T

    1987-01-01

    Measurements of ankle pressure index (API) and arterial flow velocity including calculation of pulsatility index (PI) from the common femoral and pedal arteries were performed in 89 limbs of 75 patients before and after percutaneous transluminal angioplasty (PTA) (63 iliac and 26 femoropopliteal). A pulsed wave Doppler ultrasound flowmeter was used. An increase of API at rest of at least 0.15 or the absence of pressure drop after exercise following PTA was used as criteria for a hemodynamically successful angioplasty. In patients with hemodynamically successful PTA of an iliac obstruction PI increased from 4.2 to 8.6 (p less than 0.001); 91 per cent of these patients improved clinically. When iliac angioplasty was hemodynamically unsuccessful, PI remained unchanged; 11 per cent of these patients improved clinically. All limbs with hemodynamically successful PTA of a femoropopliteal obstruction improved clinically and PI increased from 3.1 to 8.7 (p less than 0.001). After hemodynamically unsuccessful femoropopliteal PTA, PI remained unchanged though 25 per cent of these patients improved clinically. These results illustrate that measurement of arterial flow velocity with calculation of PI may be a useful supplement for the functional evaluation of the effect of PTA, since symptomatic response alone may be unreliable.

  1. Modular Ultrasound Array Doppler Velocimeter with FPGA-based Signal Processing for Real-time Flow Mapping in Liquid Metal

    NASA Astrophysics Data System (ADS)

    Nauber, R.; Thieme, N.; Beyer, H.; Büttner, L.; Räbiger, D.; Eckert, S.; Czarske, J.

    Investigating the complex interaction of conductive fluids and magnetic fields is relevant for a variety of applications from basic research in magnetohydrodynamics (MHD) to modeling industrial processes involving metal melts, such as the crystal growth process in the photovoltaic industry. This enables targeted optimizations of the melt flow and allows to significantly increase the yield and energy efficiency of industrial processes. However, experimental studies in this field are often limited by the performance of flow instrumentation for opaque liquids. We present an ultrasound array Doppler velocimeter (UADV) for flow mapping in opaque liquids at room temperature. It is modular and flexible regarding its measurement configuration, for instance it allows capturing two velocity components in two planes (2d - 2c). It uses up to 9 linear arrays with a total element count of 225, driven in a parallelized time division multiplex (TDM) scheme. A FPGA-based signal pre-processing allows to handle the massive data bandwidth of typ. 1.2 GB/s and enables a continuous and near-realtime operation of the measurement system. The capabilities of the UADV system are demonstrated in a basic MHD research experiment with a metal melt (GaInSn) in a cubic container of (67 mm)3. The flow induced by a rotating magnetic field is captured with a temporal resolution of 250 ms for the horizontal and vertical central cross-section of the cube.

  2. Transcranial Doppler ultrasound blood flow velocity and pulsatility index as systemic indicators for Alzheimer’s disease

    PubMed Central

    Roher, Alex E.; Garami, Zsolt; Tyas, Suzanne L.; Maarouf, Chera L.; Kokjohn, Tyler A.; Belohlavek, Marek; Vedders, Linda J.; Connor, Donald; Sabbagh, Marwan N.; Beach, Thomas G.; Emmerling, Mark R.

    2010-01-01

    Background Multiple lines of evidence suggest cardiovascular co-morbidities hasten the onset of Alzheimer’s disease (AD) or accelerate its course. Methods To evaluate the utility of cerebral vascular physical function/condition parameters as potential systemic indicators of AD, we employed transcranial Doppler (TCD) ultrasound to assess cerebral blood flow and vascular resistance of the 16 arterial segments comprising the circle of Willis and its major tributaries. Results Our study revealed decreased arterial mean flow velocity (MFV) and increased pulsatility index (PI) are associated with a clinical diagnosis of presumptive AD. Cerebral blood flow impairment revealed by these parameters reflects the global hemodynamic and structural consequences of a multifaceted disease process yielding diffuse congestive microvascular pathology, increased arterial rigidity, and decreased arterial compliance combined with putative age-associated cardiovascular output declines. Conclusions TCD evaluation offers direct physical confirmation of brain perfusion impairment and may ultimately provide a convenient, noninvasive means to assess the efficacy of medical interventions on cerebral blood flow or reveal incipient AD. In the near term, TCD-based direct assessments of brain perfusion may offer the prospect of preventing or mitigating AD simply by revealing patients who would benefit from interventions to improve circulatory system function. PMID:21388892

  3. Velocity Structure and Spatio-temporal Evolution in the Head Turbidity Currents based on Ultrasound Doppler Velocity Profiling

    NASA Astrophysics Data System (ADS)

    Nomura, Shun; Cesare Giovanni, De; Takeda, Yasushi; Yoshida, Taiki; Tasaka, Yuji; Sakaguchi, Hide

    2017-04-01

    Particle laden flow or turbidity current along the sea floor are important as a sediment conveyer and a formation factor of the submarine topography in the geological field. Especially, in the head of the flow, the kinematic energy is frequently exchanged through the boundary of the ambient water and the seabed floor, and it dominants the substantial dynamics of turbidity currents. An understanding of its turbulence structure helps to predict the sediment transport and layer development processes. To comprehend its dynamics precisely, flume test were conducted with continuously fed fluid quartz flour mixture supply. The flow velocities were measured at two different angles by the ultrasound Doppler velocity profiler UVP and both velocity components, in flow direction and on the vertical axis, were extracted. The fundamental velocity structure corresponds to the theories found in literature. Its spatio-temporal evolution was examined from the velocity distribution profiles along the downstream directions. Additionally, developing processes of head structures were also discussed through hydraulic statistic values such as mean velocity, Reynolds stress, and turbulent kinematic energy.

  4. Does cerebral lateralization develop? A study using functional transcranial Doppler ultrasound assessing lateralization for language production and visuospatial memory.

    PubMed

    Groen, Margriet A; Whitehouse, Andrew J O; Badcock, Nicholas A; Bishop, Dorothy V M

    2012-05-01

    In the majority of people, language production is lateralized to the left cerebral hemisphere and visuospatial skills to the right. However, questions remain as to when, how, and why humans arrive at this division of labor. In this study, we assessed cerebral lateralization for language production and for visuospatial memory using functional transcranial Doppler ultrasound in a group of 60 typically developing children between the ages of six and 16 years. The typical pattern of left-lateralized activation for language production and right-lateralized activation for visuospatial memory was found in the majority of the children (58%). No age-related change in direction or strength of lateralization was found for language production. In contrast, the strength of lateralization (independent of direction) for visuospatial memory function continued to increase with age. In addition, boys showed a trend for stronger right-hemisphere lateralization for visuospatial memory than girls, but there was no gender effect on language laterality. We tested whether having language and visuospatial functions in the same hemisphere was associated with poor cognitive performance and found no evidence for this "functional crowding" hypothesis. We did, however, find that children with left-lateralized language production had higher vocabulary and nonword reading age-adjusted standard scores than other children, regardless of the laterality of visuospatial memory. Thus, a link between language function and left-hemisphere lateralization exists, and cannot be explained in terms of maturational change.

  5. The clinical utility of vascular mapping with Doppler ultrasound prior to arteriovenous fistula construction for hemodialysis access.

    PubMed

    Ilhan, Gökhan; Esi, Ertap; Bozok, Sahin; Yürekli, Ismail; Özpak, Berkan; Özelçi, Ahmet; Destan, Bugra; Gürbüz, Ali

    2013-01-01

    To compare the outcomes of vascular access (VA) procedures performed using physical examination (PE) alone to PE and ultrasound vein mapping for assessment of patients needing hemodialysis access. Comparative analysis of data obtained by retrospective review of records of 63 patients who underwent PE and vascular mapping (VM) using colored Doppler ultrasonography (CDUS) and 76 patients assessed by physical examination alone to schedule vascular access surgery. The parameters assessed to study the impact of these two different pre-operative assessment approaches included selection of surgical site, procedure, construction of arteriovenous fistulas (AVF) and grafts (AVG), negative surgical exploration rates and surgical outcomes (maturation and patency rates). The rate of successfully constructed AVF increased significantly from 75% to 97% (P=.001) with pre-operative ultrasonographic vascular mapping. In 22 patients (34.9%) the access planned with physical examination was modified based on CDUS examination. In 12 patients, the surgical site for AVF creation and type of surgical procedure were modified based on the CDUS results. Permanent access placement rates were significantly higher in patients assessed with CDUS (P=.001). All patients who underwent vascular mapping had successful VA construction while the PE group had a 18.4% negative surgical exploration rate. When fistulas were assessed at six months, the patency rate was 80.7% for the physical examination (PE) group and 93.4% for the vascular mapping (VM) group. Pre-operative vascular mapping using CDUS significantly increases the success of AVF construction and patency.

  6. Real-time 3-D ultrasound scan conversion using a multicore processor.

    PubMed

    Zhuang, Bo; Shamdasani, Vijay; Sikdar, Siddhartha; Managuli, Ravi; Kim, Yongmin

    2009-07-01

    Real-time 3-D ultrasound scan conversion (SC) in software has not been practical due to its high computation and I/O data handling requirements. In this paper, we describe software-based 3-D SC with high volume rates using a multicore processor, Cell. We have implemented both 3-D SC approaches: 1) the separable 3-D SC where two 2-D coordinate transformations in orthogonal planes are performed in sequence and 2) the direct 3-D SC where the coordinate transformation is directly handled in 3-D. One Cell processor can scan-convert a 192 x 192 x 192 16-bit volume at 87.8 volumes/s with the separable 3-D SC algorithm and 28 volumes/s with the direct 3-D SC algorithm.

  7. Mode shape reconstruction of an impulse excited structure using continuous scanning laser Doppler vibrometer and empirical mode decomposition.

    PubMed

    Kyong, Yongsoo; Kim, Daesung; Dayou, Jedol; Park, Kyihwan; Wang, Semyung

    2008-07-01

    For vibration testing, discrete types of scanning laser Doppler vibrometer (SLDV) have been developed and have proven to be very useful. For complex structures, however, SLDV takes considerable time to scan the surface of structures and require large amounts of data storage. To overcome these problems, a continuous scan was introduced as an alternative. In this continuous method, the Chebyshev demodulation (or polynomial) technique and the Hilbert transform approach have been used for mode shape reconstruction with harmonic excitation. As an alternative, in this paper, the Hilbert-Huang transform approach is applied to impact excitation cases in terms of a numerical approach, where the vibration of the tested structure is modeled using impulse response functions. In order to verify this technique, a clamped-clamped beam was chosen as the test rig in the numerical simulation and real experiment. This paper shows that with additional innovative steps of using ideal bandpass filters and nodal point determination in the postprocessing, the Hilbert-Huang transformation can be used to create a better mode shape reconstruction even in the impact excitation case.

  8. Damage identification of beam structures using free response shapes obtained by use of a continuously scanning laser Doppler vibrometer system

    NASA Astrophysics Data System (ADS)

    Xu, Y. F.; Chen, Da-Ming; Zhu, W. D.

    2017-08-01

    Spatially dense operating deflection shapes and mode shapes can be rapidly obtained by use of a continuously scanning laser Doppler vibrometer (CSLDV) system, which sweeps its laser spot over a vibrating structure surface. This paper introduces a new type of vibration shapes called a free response shape (FRS) that can be obtained by use of a CSLDV system, and a new damage identification methodology using FRSs is developed for beam structures. An analytical expression of FRSs of a damped beam structure is derived, and FRSs from the analytical expression compare well with those from a finite element model. In the damage identification methodology, a free-response damage index (FRDI) is proposed, and damage regions can be identified near neighborhoods with consistently high values of FRDIs associated with different modes; an auxiliary FRDI is defined to assist identification of the neighborhoods. A FRDI associated with a mode consists of differences between curvatures of FRSs associated with the mode in a number of half-scan periods of a CSLDV system and those from polynomials that fit the FRSs with properly determined orders. A convergence index is proposed to determine the proper order of a polynomial fit. One advantage of the methodology is that the FRDI does not require any baseline information of an undamaged beam structure, if it is geometrically smooth and made of materials that have no stiffness and mass discontinuities. Another advantage is that FRDIs associated with multiple modes can be obtained using free response of a beam structure measured by a CSLDV system in one scan. The number of half-scan periods for calculation of the FRDI associated with a mode can be determined by use of the short-time Fourier transform. The proposed methodology was numerically and experimentally applied to identify damage in beam structures; effects of the scan frequency of a CSLDV system on qualities of obtained FRSs were experimentally investigated.

  9. Ultrasound

    MedlinePlus

    Ultrasound is a type of imaging. It uses high-frequency sound waves to look at organs and ... liver, and other organs. During pregnancy, doctors use ultrasound to view the fetus. Unlike x-rays, ultrasound ...

  10. Characterization of intraventricular flow patterns in healthy neonates from conventional color-Doppler ultrasound

    NASA Astrophysics Data System (ADS)

    Tejman-Yarden, Shai; Rzasa, Callie; Benito, Yolanda; Alhama, Marta; Leone, Tina; Yotti, Raquel; Bermejo, Javier; Printz, Beth; Del Alamo, Juan C.

    2012-11-01

    Left ventricular vortices have been difficult to visualize in the clinical setting due to the lack of quantitative non-invasive modalities, and this limitation is especially important in pediatrics. We have developed and validated a new technique to reconstruct two-dimensional time-resolved velocity fields in the LV from conventional transthoracic color-Doppler images. This non-invasive modality was used to image LV flow in 10 healthy full-term neonates, ages 24-48 hours. Our results show that, in neonates, a diastolic vortex developed during LV filling, was maintained during isovolumic contraction, and decayed during the ejection period. The vortex was created near the base of the ventricle, moved toward the apex, and then back toward the base and LVOT during ejection. In conclusion, we have characterized for the first time the properties of the LV filling vortex in normal neonates, demonstrating that this vortex channels blood from the inflow to the outflow tract of the LV. Together with existing data from adults, our results confirm that the LV vortex is conserved through adulthood. Funded by NIH Grant R21HL108268.

  11. Use of Transcranial Doppler Ultrasound for Diagnosis of Brain Death in Patients with Severe Cerebral Injury.

    PubMed

    Li, Yuequn; Liu, Shangwei; Xun, Fangfang; Liu, Zhan; Huang, Xiuying

    2016-06-06

    BACKGROUND The aim of this study was to investigate the use of transcranial Doppler (TCD) for diagnosis of brain death in patients with severe cerebral injury. MATERIAL AND METHODS This retrospective study enrolled 42 patients based on inclusion and exclusion criteria. All patients were divided into either the brain death group or the survival group according to prognosis. Blood flow of the brain was examined by TCD and analyzed for spectrum changes. The average blood flow velocity (Vm), pulse index (PI), and diastolic blood flow in reverse (RDF) were recorded and compared. RESULTS The data demonstrated that the average speed of bilateral middle cerebral artery blood flow in the brain death group was significantly reduced (P<0.05). However, the PI of the brain death group increased significantly. Moreover, RDF spectrum and nail-like sharp peak spectrum of the brain death group was higher than in the survival group. CONCLUSIONS Due to its simplicity, high repeatability, and specificity, TCD combined with other methods is highly valuable for diagnosis of brain death in patients with severe brain injury.

  12. Denoising embolic Doppler ultrasound signals using Dual Tree Complex Discrete Wavelet Transform.

    PubMed

    Serbes, Gorkem; Aydin, Nizamettin

    2010-01-01

    Early and accurate detection of asymptomatic emboli is important for monitoring of preventive therapy in stroke-prone patients. One of the problems in detection of emboli is the identification of an embolic signal caused by very small emboli. The amplitude of the embolic signal may be so small that advanced processing methods are required to distinguish these signals from Doppler signals arising from red blood cells. In this study instead of conventional discrete wavelet transform, the Dual Tree Complex Discrete Wavelet Transform was used for denoising embolic signals. Performances of both approaches were compared. Unlike the conventional discrete wavelet transform discrete complex wavelet transform is a shift invariant transform with limited redundancy. Results demonstrate that the Dual Tree Complex Discrete Wavelet Transform based denoising outperforms conventional discrete wavelet denoising. Approximately 8 dB improvement is obtained by using the Dual Tree Complex Discrete Wavelet Transform compared to the improvement provided by the conventional Discrete Wavelet Transform (less than 5 dB).

  13. Inverse Problem for Color Doppler Ultrasound-Assisted Intracardiac Blood Flow Imaging

    PubMed Central

    Jang, Jaeseong

    2016-01-01

    For the assessment of the left ventricle (LV), echocardiography has been widely used to visualize and quantify geometrical variations of LV. However, echocardiographic image itself is not sufficient to describe a swirling pattern which is a characteristic blood flow pattern inside LV without any treatment on the image. We propose a mathematical framework based on an inverse problem for three-dimensional (3D) LV blood flow reconstruction. The reconstruction model combines the incompressible Navier-Stokes equations with one-direction velocity component of the synthetic flow data (or color Doppler data) from the forward simulation (or measurement). Moreover, time-varying LV boundaries are extracted from the intensity data to determine boundary conditions of the reconstruction model. Forward simulations of intracardiac blood flow are performed using a fluid-structure interaction model in order to obtain synthetic flow data. The proposed model significantly reduces the local and global errors of the reconstructed flow fields. We demonstrate the feasibility and potential usefulness of the proposed reconstruction model in predicting dynamic swirling patterns inside the LV over a cardiac cycle. PMID:27313657

  14. Inverse Problem for Color Doppler Ultrasound-Assisted Intracardiac Blood Flow Imaging.

    PubMed

    Jang, Jaeseong; Ahn, Chi Young; Choi, Jung-Il; Seo, Jin Keun

    2016-01-01

    For the assessment of the left ventricle (LV), echocardiography has been widely used to visualize and quantify geometrical variations of LV. However, echocardiographic image itself is not sufficient to describe a swirling pattern which is a characteristic blood flow pattern inside LV without any treatment on the image. We propose a mathematical framework based on an inverse problem for three-dimensional (3D) LV blood flow reconstruction. The reconstruction model combines the incompressible Navier-Stokes equations with one-direction velocity component of the synthetic flow data (or color Doppler data) from the forward simulation (or measurement). Moreover, time-varying LV boundaries are extracted from the intensity data to determine boundary conditions of the reconstruction model. Forward simulations of intracardiac blood flow are performed using a fluid-structure interaction model in order to obtain synthetic flow data. The proposed model significantly reduces the local and global errors of the reconstructed flow fields. We demonstrate the feasibility and potential usefulness of the proposed reconstruction model in predicting dynamic swirling patterns inside the LV over a cardiac cycle.

  15. Fincke performs an ultrasound bone scan on Padalka using the ADUM in the U.S. Lab during Expedition 9

    NASA Image and Video Library

    2004-08-10

    ISS009-E-17439 (10 August 2004) --- Astronaut Edward M. (Mike) Fincke (foreground), Expedition 9 NASA ISS science officer and flight engineer, performs an ultrasound bone scan on cosmonaut Gennady I. Padalka, commander representing Russia's Federal Space Agency. The two are using the Advanced Diagnostic Ultrasound in Micro-G (ADUM) in the Destiny laboratory of the International Space Station (ISS). The ADUM keyboard, flat screen display and front control panel are visible at right.

  16. Design of integrated scanning laser Doppler velocitmeter using arrayed waveguide gratings

    NASA Astrophysics Data System (ADS)

    Maru, Koichi; Fujii, Yusaku; Obokata, Tomio; Ishima, Tsuneaki; Yupapin, Preecha; Pornsuwancharoen, Nithitroth; Juthanggoon, Thanaprasert

    2009-07-01

    An integrated scanned differential LDV has been proposed using planar lightwave circuit (PLC) technology. By using the proposed LDV, the measurement position can be scanned in depth direction without any mechanical movement. The PLC technology is utilized in the proposed design for achieving a compact optical circuit. The characteristics of the proposed LDV are simulated with a design model based on grating equations for AWGs. The simulation result reveals that the measurement position can be changed over the range of 46 mm in the depth direction without mechanical movement when the displacement between output sides of two waveguide arrays is 30 mm.

  17. Renal length discrepancy by ultrasound is a reliable predictor of an abnormal DMSA scan in children.

    PubMed

    Khazaei, Mahmood R; Mackie, Fiona; Rosenberg, Andrew R; Kainer, Gad

    2008-01-01

    A renal length discrepancy (RLD) of more than 10 mm by ultrasound (US) is accepted as a potential indicator of an underlying renal pathology; however, there are few supporting data for this in children. Our objective was to determine a cutoff at which RLD on US is a reliable predictor of dimercaptosuccinate acid (DMSA) scan abnormality. We present data from 90 patients who had both renal US and a DMSA scan, as well as DMSA scan results compared with bipolar RLD by US. Positive (PPV) and negative (NPV) predictive values were calculated for renal RLD from 6 to >10 mm. The left kidney was longer in 56%, whereas the right kidney was longer in 37%; their lengths were equal in 8%. For children at all ages, a left kidney longer than the right by >or=10 mm or a right kidney longer than the left by >or=7 mm gave a PPV for DMSA abnormality of 79% and 100%, respectively. In children older than 4 years, if the right kidney was longer by >or=7 mm or if the left kidney was longer by >or=10 mm, the PPVs for DMSA abnormality were 100% and 63%, respectively. In children younger than 4 years, when the right kidney was longer by >or=6 mm or the left was kidney longer by >or=10 mm, the PPV were 86% and 100%, respectively. Thus, children with a right kidney longer than the left by even <10 mm is a reliable predictor of an abnormal DMSA scan.

  18. Novel automatic detection of pleura and B-lines (comet-tail artifacts) on in vivo lung ultrasound scans

    NASA Astrophysics Data System (ADS)

    Moshavegh, Ramin; Hansen, Kristoffer Lindskov; Møller Sørensen, Hasse; Hemmsen, Martin Christian; Ewertsen, Caroline; Nielsen, Michael Bachmann; Jensen, Jørgen Arendt

    2016-04-01

    This paper presents a novel automatic method for detection of B-lines (comet-tail artifacts) in lung ultrasound scans. B-lines are the most commonly used artifacts for analyzing the pulmonary edema. They appear as laser-like vertical beams, which arise from the pleural line and spread down without fading to the edge of the screen. An increase in their number is associated with presence of edema. All the scans used in this study were acquired using a BK3000 ultrasound scanner (BK Ultrasound, Denmark) driving a 192-element 5:5 MHz wide linear transducer (10L2W, BK Ultrasound). The dynamic received focus technique was employed to generate the sequences. Six subjects, among those three patients after major surgery and three normal subjects, were scanned once and Six ultrasound sequences each containing 50 frames were acquired. The proposed algorithm was applied to all 300 in-vivo lung ultrasound images. The pleural line is first segmented on each image and then the B-line artifacts spreading down from the pleural line are detected and overlayed on the image. The resulting 300 images showed that the mean lateral distance between B-lines detected on images acquired from patients decreased by 20% in compare with that of normal subjects. Therefore, the method can be used as the basis of a method of automatically and qualitatively characterizing the distribution of B-lines.

  19. Using dynamic infrared thermography to optimize color Doppler ultrasound mapping of cutaneous perforators.

    PubMed

    Muntean, Maximilian Vlad; Strilciuc, Stefan; Ardelean, Filip; Pestean, Cosmin; Lacatus, Radu; Badea, Alexandru Florin; Georgescu, Alexandru

    2015-12-01

    The high technical demands associated with perforator flaps demand a precise preoperative identification and evaluation of perforator vessels. Color Doppler Ultrasonography (CDU) and Dynamic Infrared Thermography (DIRT) are currently used for preoperative perforator mapping. Each individual technique has advantages and disadvantages. The purpose of this paper is to analyze the value of combining the two methods in order to optimize the process of preoperative perforator mapping. CDU and DIRT were used for preoperative perforator mapping in 10 pigs. The results were compared to intraoperative findings. Total number of perforators, localization, and identification of the dominant perforator was analyzed for each method. The examination time was recorded for each procedure. Both methods had a high sensitivity in determining the number and localization of perforators when compared to those identified during surgery. DIRT produced a higher number of false positive results. CDU accurately identified the emergence of the perforators in the fascia in all cases. Both methods correctly identified the dominant perforator. The sensitivity, positive predictive value, and accuracy of CDU were 93.56%, 97%, and 91.30% respectively and for DIRT 95.05%, 80.67%, and 77.41% respectively. The average examination was 39.76 minutes for CDU and 10.24 minutes for DIRT. The average time taken into account for the analysis of a single perforator in order to confirm DIRT findings was 1.83 minutes. Preoperative perforator mapping has become a compulsory step in nearly all reconstructive procedures. In our study, both CDU and DIRT correctly identified the dominant perforator in all cases. By combining the two examinations overall mapping time can be reduced significantly. A reduced examination time translates into increased patient compliance and a lower procedure cost. The combined mapping technique facilitates the selection of the ideal perforator in all cases. Correctly identifying the

  20. Hepatic artery duplex Doppler ultrasound in severe alcoholic hepatitis and correlation with Maddrey's discriminant function.

    PubMed

    Abhilash, Haridas; Mukunda, Madhavan; Sunil, Premaletha; Devadas, Krishnadas; Vinayakumar, Katoor Ramakrishnan Nair

    2015-01-01

    Alcoholic hepatitis is associated with altered hepatic artery hemodynamics. Maddrey's discriminant function (MDF) can identify patients with poor prognosis (DF >32). We studied hepatic artery hemodynamic parameters of hepatic artery diameter (HAD), resistive index (RI) and pulsatility index (PI) in severe acute alcoholic hepatitis (SAAH) and for the presence of correlation of parameters with severity factor MDF. A total of 20 consecutive SAAH patients defined as MDF >32 and a group of 20 alcoholic cirrhosis patients without alcoholic hepatitis formed the two study groups. Hepatic artery Doppler parameters HAD, RI, PI were determined after admission in the Gastroenterology Department, Government Medical College, Thiruvananthapuram, India. MDF score of SAAH was calculated at the time of admission to the hospital. The mean HAD showed statistically significant increase in SAAH compared with cirrhosis (3.96±0.51 vs. 2.86±0.41, P<0.001). There was statistically significant decrease in mean RI (0.49±0.08 vs. 0.81±0.09, P<0.001) and mean PI (1.67±0.13 vs. 1.80±0.13, P<0.001) in SAAH compared with alcoholic cirrhosis. Statistically significant correlation between MDF and HAD (r=0.63, P<0.003) was found in SAAH. On linear regression, 36% of the variability in MDF could be independently predicted by HAD. Hepatic artery parameters of HAD, RI, PI had a significant difference in SAAH compared with alcoholic cirrhosis patients thereby being useful as a diagnostic tool. HAD showed correlation with MDF score assessing the severity of alcoholic hepatitis and may be a useful non-invasive prognostic tool.

  1. Non-visualization of the internal carotid artery with a normal ipsilateral common carotid artery Doppler waveform: a finding suggesting congenital absence of the ICA on colour Doppler ultrasound.

    PubMed

    Yilmaz, C; Utebay, B; Kalaycioglu, S; Onat, G; Solak, A

    2006-09-01

    We report a case of congenital absence of the left internal carotid artery (ICA) that presented with left-sided facial numbness. On MRI of the brain, occlusion of the left cavernous ICA was suggested. On colour Doppler ultrasound (CDS), the left ICA was not visualized and the ipsilateral common carotid artery (CCA) showed normal flow in systole and diastole. Combined with the correct identification of the left external carotid artery (ECA), these findings were suggestive of congenital absence of the ICA rather than occlusion. The final diagnosis of congenital absence of the ICA was confirmed with CT of the skull base.

  2. Bayesian inference of genetic parameters for ultrasound scanning traits of Kivircik lambs.

    PubMed

    Cemal, I; Karaman, E; Firat, M Z; Yilmaz, O; Ata, N; Karaca, O

    2017-03-01

    Ultrasound scanning traits have been adapted in selection programs in many countries to improve carcass traits for lean meat production. As the genetic parameters of the traits interested are important for breeding programs, the estimation of these parameters was aimed at the present investigation. The estimated parameters were direct and maternal heritability as well as genetic correlations between the studied traits. The traits were backfat thickness (BFT), skin+backfat thickness (SBFT), eye muscle depth (MD) and live weights at the day of scanning (LW). The breed investigated was Kivircik, which has a high quality of meat. Six different multi-trait animal models were fitted to determine the most suitable model for the data using Bayesian approach. Based on deviance information criterion, a model that includes direct additive genetic effects, maternal additive genetic effects, direct maternal genetic covariance and maternal permanent environmental effects revealed to be the most appropriate for the data, and therefore, inferences were built on the results of that model. The direct heritability estimates for BFT, SBFT, MD and LW were 0.26, 0.26, 0.23 and 0.09, whereas the maternal heritability estimates were 0.27, 0.27, 0.24 and 0.20, respectively. Negative genetic correlations were obtained between direct and maternal effects for BFT, SBFT and MD. Both direct and maternal genetic correlations between traits were favorable, whereas BFT-MD and SBFT-MD had negligible direct genetic correlation. The highest direct and maternal genetic correlations were between BFT and SBFT (0.39) and between MD and LW (0.48), respectively. Our results, in general, indicated that maternal effects should be accounted for in estimation of genetic parameters of ultrasound scanning traits in Kivircik lambs, and SBFT can be used as a selection criterion to improve BFT.

  3. Effects of intravenous bolus injection of nicorandil on renal artery flow velocity assessed by color Doppler ultrasound.

    PubMed

    Shimamoto, Yukiko; Kubo, Takashi; Tanabe, Kazumi; Emori, Hiroki; Katayama, Yosuke; Nishiguchi, Tsuyoshi; Taruya, Akira; Kameyama, Takeyoshi; Orii, Makoto; Yamano, Takashi; Kuroi, Akio; Yamaguchi, Tomoyuki; Takemoto, Kazushi; Matsuo, Yoshiki; Ino, Yasushi; Tanaka, Atsushi; Hozumi, Takeshi; Terada, Masaki; Akasaka, Takashi

    2017-01-01

    Previous animal studies have shown that a potassium channel opener, nicorandil, provokes vasodilation in renal microvasculature and increases renal blood flow. We conducted a clinical study that aimed to evaluate the effect of nicorandil on renal artery blood flow in comparison with nitroglycerin by using color Doppler ultrasound. The present study enrolled 40 patients with stable coronary artery disease who had no renal arterial stenosis and renal parenchymal disease. The patients received intravenous administration of nicorandil (n=20) or nitroglycerin (n=20). Before and after the administration, renal artery blood flow velocity was measured by color-guided pulsed-wave Doppler. The peak-systolic, end-diastolic, and mean renal artery blood flow velocities before the administration were not different between the nicorandil group and the nitroglycerin group. The peak-systolic (79±15cm/s to 99±21cm/s, p<0.001; and 78±19cm/s to 85±19cm/s, p=0.004), end-diastolic (22±5cm/s to 28±8cm/s, p<0.001; and 24±6cm/s to 26±6cm/s, p=0.005) and mean (41±6cm/s to 49±9cm/s, p<0.001; and 43±9cm/s to 45±9cm/s, p=0.009) renal artery flow velocities increased significantly in either group. The nominal changes in the peak-systolic (20±10cm/s vs. 7±8cm/s, p<0.001), end-diastolic (5±4cm/s vs. 2±3cm/s, p=0.001), and mean (8±5cm/s vs. 2±2cm/s, p<0.001) renal artery blood flow velocities were significantly greater in the nicorandil group compared with the nitroglycerin group. Intravenous nicorandil increased renal artery blood flow velocity in comparison with nitroglycerin. Nicorandil has a significant effect on renal hemodynamics. Copyright © 2016 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

  4. A Brain-computer Interface based on Functional Transcranial Doppler Ultrasound Using Wavelet Transform and Support Vector Machines.

    PubMed

    Khalaf, Aya; Sybeldon, Matthew; Sejdic, Ervin; Akcakaya, Murat

    2017-10-07

    Functional transcranial Doppler (fTCD) is an ultrasound based neuroimaging technique used to assess neural activation that occurs during a cognitive task through measuring velocity of cerebral blood flow. The objective of this paper is to investigate the feasibility of a 2-class and 3-class real-time BCI based on blood flow velocity in left and right middle cerebral arteries in response to mental rotation and word generation tasks. Statistical features based on a five-level wavelet decomposition were extracted from the fTCD signals. The Wilcoxon test and support vector machines (SVM), with a linear kernel, were employed for feature reduction and classification. The experimental results showed that within approximately 3seconds of the onset of the cognitive task average accuracies of 80.29%, and 82.35% were obtained for the mental rotation versus resting state and the word generation versus resting state respectively. The mental rotation task versus word generation task achieved an average accuracy of 79.72% within 2.24seconds from the onset of the cognitive task. Furthermore, an average accuracy of 65.27% was obtained for the 3-class problem within 4.68seconds. The results presented here provide significant improvement compared to the relevant fTCD-based systems presented in literature in terms of accuracy and speed. Specifically, the reported speed in this manuscript is at least 12 and 2.5 times faster than any existing binary and 3-class fTCD-based BCIs, respectively. These results show fTCD as a promising and viable candidate to be used towards developing a real-time BCI. Published by Elsevier B.V.

  5. The value of power Doppler ultrasound in patients with rheumatoid arthritis in clinical remission: Reclassifying disease activity?

    PubMed

    Vergara, Facundo; Ruta, Santiago; Rosa, Javier; Marín, Josefina; García-Mónaco, Ricardo; Soriano, Enrique R

    2017-03-18

    The aim of the present study was to describe the ultrasound (US) findings in patients with rheumatoid arthritis (RA) in clinical remission, and to evaluate the ability of power Doppler (PD) US to reclassify disease activity in these patients. We included consecutive patients with RA according to 2010 American College of Rheumatology/European League Against Rheumatism criteria, who were in clinical remission by the Disease Activity Score (DAS28<2.6). Twenty joints of both hands were assessed by US. PD signal was evaluated on a semi-quantitative scale from 0 to 3. Three different US-modified DAS28 (US-DAS28) were constructed, replacing the clinical swollen joint count by the PD US joint count using PD score ≥1, ≥2 or ≥3, respectively. Eighty-six patients were included. Twenty-three (26.7%) patients had at least one joint with abnormal US-positive PD signal. Thirteen percent of patients were reclassified to low disease activity by applying the US-DAS28 when joints were considered active with a PD signal ≥1; 12%, when a PD signal ≥2 was considered, and 2% of the patients were reclassified when a PD score of 3 was considered. No patients were reclassified to a level of moderate or high activity applying US-DAS28. Although around a quarter of patients with RA in clinical remission showed PD US features indicating residual activity, only a small percentage were reclassified to a state of low activity and none to a level of moderate or high activity, applying the proposed US-DAS28. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.

  6. Studying cerebral hemodynamics and metabolism using simultaneous near-infrared spectroscopy and transcranial Doppler ultrasound: a hyperventilation and caffeine study

    PubMed Central

    Yang, Runze; Brugniaux, Julien; Dhaliwal, Harinder; Beaudin, Andrew E; Eliasziw, Misha; Poulin, Marc J; Dunn, Jeff F

    2015-01-01

    Caffeine is one of the most widely consumed psycho-stimulants in the world, yet little is known about its effects on brain oxygenation and metabolism. Using a double-blind, placebo-controlled, randomized cross-over study design, we combined transcranial Doppler ultrasound (TCD) and near-infrared spectroscopy (NIRS) to study caffeine's effect on middle cerebral artery peak blood flow velocity (Vp), brain tissue oxygenation (StO2), total hemoglobin (tHb), and cerebral oxygen metabolism (CMRO2) in five subjects. Hyperventilation-induced hypocapnia served as a control to verify the sensitivity of our measurements. During hypocapnia (∼16 mmHg below resting values), Vp decreased by 40.0 ± 2.4% (95% CI, P < 0.001), while StO2 and tHb decreased by 2.9 ± 0.3% and 2.6 ± 0.4%, respectively (P = 0.003 and P = 0.002, respectively). CMRO2, calculated using the Fick equation, was reduced by 29.3 ± 9% compared to the isocapnic-euoxia baseline (P < 0.001). In the pharmacological experiments, there was a significant decrease in Vp, StO2, and tHb after ingestion of 200 mg of caffeine compared with placebo. There was no significant difference in CMRO2 between caffeine and placebo. Both showed a CMRO2 decline compared to baseline showing the importance of a placebo control. In conclusion, this study showed that profound hypocapnia impairs cerebral oxidative metabolism. We provide new insight into the effects of caffeine on cerebral hemodynamics. Moreover, this study showed that multimodal NIRS/TCD is an excellent tool for studying brain hemodynamic responses to pharmacological interventions and physiological challenges. PMID:25907789

  7. Noninvasive assessment of sympathetic vasoconstriction in human and rodent skeletal muscle using near-infrared spectroscopy and Doppler ultrasound.

    PubMed

    Fadel, Paul J; Keller, David M; Watanabe, Hitoshi; Raven, Peter B; Thomas, Gail D

    2004-04-01

    The precise role of the sympathetic nervous system in the regulation of skeletal muscle blood flow during exercise has been challenging to define in humans, partly because of the limited techniques available for measuring blood flow in active muscle. Recent studies using near-infrared (NIR) spectroscopy to measure changes in tissue oxygenation have provided an alternative method to evaluate vasomotor responses in exercising muscle, but this approach has not been fully validated. In this study, we tested the hypothesis that sympathetic activation would evoke parallel changes in tissue oxygenation and blood flow in resting and exercising muscle. We simultaneously measured tissue oxygenation with NIR spectroscopy and blood flow with Doppler ultrasound in skeletal muscle of conscious humans (n = 13) and anesthetized rats (n = 9). In resting forearm of humans, reflex activation of sympathetic nerves with the use of lower body negative pressure produced graded decreases in tissue oxygenation and blood flow that were highly correlated (r = 0.80, P < 0.0001). Similarly, in resting hindlimb of rats, electrical stimulation of sympathetic nerves produced graded decreases in tissue oxygenation and blood flow velocity that were highly correlated (r = 0.93, P < 0.0001). During rhythmic muscle contraction, the decreases in tissue oxygenation and blood flow evoked by sympathetic activation were significantly attenuated (P < 0.05 vs. rest) but remained highly correlated in both humans (r = 0.80, P < 0.006) and rats (r = 0.92, P < 0.0001). These data indicate that, during steady-state metabolic conditions, changes in tissue oxygenation can be used to reliably assess sympathetic vasoconstriction in both resting and exercising skeletal muscle.

  8. [Transabdominal ultrasound examination, contrast-enhanced ultrasound examination and endoscopic ultrasound scanning in the determination of the aetiology and the degree of severity in acute pancreatitis].

    PubMed

    Møller Andersen, Anders; Malmstrøm, Marie Louise; Novovic, Srdan; Jørgensen, Lars Nannestad; Nissen, Flemming Helge; Hansen, Mark Berner

    2013-05-20

    A transabdominal ultrasound examination is part of the standard work-up for patients with acute pancreatitis. Transabdominal ultrasound examination displays a high sensitivity for the detection of gallbladder stones. With the recent introduction of contrast enhancement in ultrasound it has become possible to determine the severity of acute pancreatitis. Endoscopic ultrasound has shown a high sensitivity in the diagnosis of stones in the common bile duct and is an important peroperative surgical tool in endoscopic transgastric necrosectomi as well.

  9. Splanchnic Hemodynamics and Intestinal Vascularity in Crohn's Disease: An In Vivo Evaluation Using Doppler and Contrast-Enhanced Ultrasound and Biochemical Parameters.

    PubMed

    Maconi, Giovanni; Asthana, Anil K; Bolzacchini, Elena; Dell'Era, Alessandra; Furfaro, Federica; Bezzio, Cristina; Salvatore, Veronica; Maier, Jeanette A M

    2016-01-01

    Crohn's disease (CD) is characterized by inflammation and angiogenesis of affected bowel. We evaluated the correlation among vascularity of intestinal wall in CD, splanchnic hemodynamics, clinical activity and biochemical parameters of inflammation and angiogenesis. Sixteen patients with ileal CD and 10 healthy controls were investigated by means of Doppler ultrasound of the superior mesenteric artery and color Doppler and contrast-enhanced ultrasound of the ileal wall. In parallel, serum levels of vascular endothelial growth factor, tumor necrosis factor-α (TNF-α) and nitric oxide, before and 30 min after a standard meal, were evaluated. In CD patients, there was a significant post-prandial reduction in the resistance index and pulsatility index of the superior mesenteric artery, associated with increased levels of nitric oxide and decreased amounts of TNF-α. A correlation was observed between vascular endothelial growth factor and contrast-enhanced ultrasound parameters of intestinal wall vascularity (r = 0.63-0.71, p < 0.05) and between these parameters and superior mesenteric artery blood flow after fasting (resistance and pulsatility indexes: r = -0.64 and -0.72, p < 0.05). Our results revealed a post-prandial increase in nitric oxide and decrease in TNF-α in CD patients in vivo. They also confirm the role of vascular endothelial growth factor in angiogenesis and in pathologic vascular remodeling of CD and its effect on splanchnic blood flow.

  10. A microfabricated water-immersible scanning mirror with a small form factor for handheld ultrasound and photoacoustic microscopy

    NASA Astrophysics Data System (ADS)

    Xu, Song; Huang, Chih-Hsien; Zou, Jun

    2016-03-01

    Micro scanning mirrors that can operate reliably under water is useful in both ultrasound and photoacoustic microscopic imaging, where fast scanning of focused high-frequency ultrasound beams is desired for pixel-by-pixel data acquisition. This paper reports the development of a new micro-fabricated water-immersible scanning mirror with a small form factor. It consists of an optically and acoustically reflective mirror plate, which is supported onto two flexible polymer hinges and driven by an integrated electromagnetic micro-actuator. It can achieve one-axis scanning of +/-12.1° at a resonant frequency of 250Hz in air and 210Hz in water, respectively. By optimizing the design and enhancing the fabrication with high-precision optical 3D printing, the overall size of the scanning mirror module is less than 7 mm × 5 mm × 7 mm. The small form factor, large scanning angle, and high resonant frequency of the new water-immersible scanning mirror make it suitable for building compact handheld imaging probes for in-vivo high-speed and wide-field ultrasound and photoacoustic microscopy.

  11. Observations on the female reproductive cycle of captive giant tortoises (Geochelone spp.) using ultrasound scanning.

    PubMed

    Casares, M; Rübel, A; Honegger, R E

    1997-09-01

    The reproductive activities of one adult female Galápagos tortoise (Geochelone nigra) and three adult female Aldabra tortoises (Geochelone gigantea) were monitored over 2 yr using ultrasound scanning. A nonrestraining technique of tactile stimulation was used for all examinations. Developing, preovulatory, and atretic ovarian follicles, as well as eggs at various stages of shell deposition, were identified and measured. In G. nigra, follicles became preovulatory at a diameter of 40-42 mm and eggs were laid 34-84 days (mean = 55.6, n = 5) after the thin-shelled eggs were first detected in the oviducts. Geochelone nigra was capable of retaining eggs, with the shell already formed, until the next breeding season. No eggs have been produced by G. gigantea during their stay in Zürich Zoo although follicles of 38-40 mm have been observed frequently in two animals.

  12. Very high prevalence of ultrasound thyroid scan abnormalities in healthy volunteers in Modena, Italy.

    PubMed

    Gnarini, V L; Brigante, G; Della Valle, E; Diazzi, C; Madeo, B; Carani, C; Rochira, V; Simoni, M

    2013-10-01

    Italy is characterized by high prevalence of goiter. To date, only limited data about the prevalence of goiter in the Italian adult population are available. To investigate the prevalence of thyroid ultrasound abnormalities in adults unaware of any thyroid disease and evaluate the rate of differentiated thyroid cancer (DTC) obtained by this intervention. Ultrasound (US) thyroid scan was performed in adult volunteers recruited by advertisement in Modena, Italy. One hundred and thirty-five women and 66 men (no.= 201), unaware of any thyroid disease (mean age of 46 ± 10.7 yr) underwent their first thyroid US scan. US thyroid abnormalities were found in 101 subjects (50.3%): 91 nodular goiters (45.2%) and 13 US-thyroiditis (6.5%) associated with positive auto-antibodies in 11 of them. Seventeen subjects (18%) with nodules underwent US-fine needle aspiration biopsy with the following cytological class (C) outcome: 14 patients C2 (82%), 1 patient C3 (6%), 2 patients had C4 (12%), the latter received histological confirmation. The prevalence of thyroid abnormalities is very high in subjects unaware of any thyroid disease. DTC was found in 1% of subjects and in 2% of those affected by nodular goiter. Compared to the detection rate of the well-established screening programs for breast (0.45%) and colorectal (0.27%) cancer, the prevalence of DTC seems to be much higher. Thyroid US screening could allow the detection of DTC in asymptomatic subjects and this diagnosis often includes DTC at an advanced stage. Thus, US screening not necessarily results in the over-diagnosis of clinically not relevant thyroid diseases.

  13. Accuracy of sonographic fetal gender determination: predictions made by sonographers during routine obstetric ultrasound scans

    PubMed Central

    Pollard, Karen; Garbett, Ian

    2015-01-01

    Abstract Objectives: The purpose of this study was to determine the accuracy of sonographer predictions of fetal gender during routine ultrasounds. Primarily, the study sought to investigate the accuracy of predictions made in the first trimester, as requests from parents wanting to know the gender of their fetus at this early scan are becoming increasingly common. Second and third trimester fetuses were included in the study to confirm the accuracy of later predictions. In addition, the mother's decision to know the gender was recorded to determine the prevalence of women wanting prenatal predictions. Methods: A prospective, cross sectional study was conducted in a specialist private obstetric practice in the Illawarra, NSW. A total of 640 fetuses across three trimesters were examined collectively by seven sonographers. Fetal gender was predicted using the sagittal plane only in the first trimester and either the sagittal or transverse plane in later trimesters. Phenotypic gender confirmation was obtained from hospital records or direct telephone contact with women postnatally. Results: Results confirmed 100% accuracy in predictions made after 14 weeks gestation. The overall success rate in the first trimester group (11–14 weeks) was 75%. When excluding those scans where a prediction could not be made, success rates increased to 91%. Results were less accurate for fetuses younger than 12 weeks, with an overall success rate of 54%. Male fetuses under 13 weeks were more likely to have gender incorrectly or unable to be assigned. After 13 weeks, success rates for correctly predicting males exceeded that of female fetuses. Statistical differences were noted in the success rates of individual sonographers. Sixty seven percent of women were in favour of knowing fetal gender from ultrasound. Publicly insured women were more likely to request gender disclosure than privately insured women. Conclusions: Sonographic gender determination provides high success rates in the

  14. Book: Genetics for obstetricians and gynaecologists: Chapter: Genetic markers on ultrasound scan.

    PubMed

    Sivanathan, Janani; Thilaganathan, Basky

    2017-07-01

    Prenatal diagnosis is a rapidly evolving speciality. Screening for aneuploidy begins with non-sonographic features of background risk of maternal age and past and family history. It is possible to diagnose major structural defects in the foetus using second trimester scans. Serum biochemistry markers in the early second trimester were added to increase the detection rate of aneuploidy. However, as some of these abnormalities were amenable to detection earlier in the first trimester, newer modalities were introduced. Nuchal translucency (NT) measurement was one of the main advances with regard to first trimester screening. Additional markers such as the presence of nasal bone, tricuspid regurgitation, ductus venosus and megacystis; together with first trimester serum biochemistry, further enhanced the detection rate of chromosomal abnormalities. Advances in research and technology have resulted in the availability of non-invasive prenatal testing from 10 weeks of gestation. This has facilitated the detection of the three major chromosomal aneuploidies at very early gestation. However, there are a wide range of genetic syndromes that are not confined to the main trisomies. There are specific markers on ultrasound that can be linked to specific syndromes. Hence, a structured and stepwise approach is needed to identify and reach a possible diagnosis. As anomalies are classified into malformations, deformations and disruptions, it is important to note that not all markers detected are due to genetic syndromes and not all genetic syndromes can be detected on ultrasound scan. In this chapter, we outline common structural markers and their association with main genetic syndromes. Copyright © 2017. Published by Elsevier Ltd.

  15. The effects of probe placement on measured flow velocity in transcranial Doppler ultrasound imaging in-vitro and in-vivo experiments

    NASA Astrophysics Data System (ADS)

    de Jong, Daan L. K.; Meel-van den Abeelen, Aisha S. S.; Lagro, Joep; Claassen, Jurgen A. H. R.; Slump, Cornelis H.

    2014-03-01

    The measurement of the blood flow in the middle cerebral artery (MCA) using transcranial Doppler ultrasound (US) imaging is clinically relevant for the study of cerebral autoregulation. Especially in the aging population, impairement of the autoregulation may coincide or relate to loss of perfusion and consequently loss of brain function. The cerebral autoregulation can be assessed by relating the blood pressure to the blood flow in the brain. Doppler US is a widely used, non-invasive method to measure the blood flow in the MCA. However, Doppler flow imaging is known to produce results that are dependent of the operator. The angle of the probe insonation with respect to the centerline of the blood vessel is a well known factor for output variability. In patients also the skull must be traversed and the MCA must be detected, influencing the US signal intensity. In this contribution we report two studies. We describe first an in-vitro setup to study the Doppler flow in a situation where the ground truth is known. Secondly, we report on a study with healthy volunteers where the effects of small probe displacements on the flow velocity signals are investigated. For the latter purpose, a special probe holder was designed to control the experiment.

  16. Comparison of blood velocity measurements between ultrasound Doppler and accelerated phase-contrast MR angiography in small arteries with disturbed flow

    NASA Astrophysics Data System (ADS)

    Jiang, Jingfeng; Strother, Charles; Johnson, Kevin; Baker, Sara; Consigny, Dan; Wieben, Oliver; Zagzebski, James

    2011-03-01

    Ultrasound Doppler (UD) velocity measurements are commonly used to quantify blood flow velocities in vivo. The aim of our work was to investigate the accuracy of in vivo spectral Doppler measurements of velocity waveforms. Waveforms were derived from spectral Doppler signals and corrected for intrinsic spectral broadening errors by applying a previously published algorithm. The method was tested in a canine aneurysm model by determining velocities in small arteries (3-4 mm diameter) near the aneurysm where there was moderately disturbed flow. Doppler results were compared to velocity measurements in the same arteries acquired with a rapid volumetric phase contrast MR angiography technique named phase contrast vastly undersampled isotropic projection reconstruction magnetic resonance angiography (PC-VIPR MRA). After correcting for intrinsic spectral broadening, there was a high degree of correlation between velocities obtained by the real-time UD and the accelerated PC-MRA technique. The peak systolic velocity yielded a linear correlation coefficient of r = 0.83, end diastolic velocity resulted in r = 0.81, and temporally averaged mean velocity resulted in r = 0.76. The overall velocity waveforms obtained by the two techniques were also highly correlated (r = 0.89 ± 0.06). There were, however, only weak correlations for the pulsatility index (PI: 0.25) and resistive index (RI: 0.14) derived from the two techniques. Results demonstrate that to avoid overestimations of peak systolic velocities, the results for UD must be carefully corrected to compensate for errors caused by intrinsic spectral broadening.

  17. Comparison of Blood Velocity Measurements between Ultrasound Doppler and Accelerated Phase-Contrast MR Angiography in Small Arteries with Disturbed Flow

    PubMed Central

    Jiang, Jingfeng; Strother, Charles; Johnson, Kevin; Baker, Sara; Consigny, Dan; Wieben, Oliver; Zagzebski, James

    2011-01-01

    Ultrasound Doppler (UD) velocity measurements are commonly used to quantify blood flow velocities in vivo. The aim of our work was to investigate the accuracy of in vivo spectral Doppler measurements of velocity waveforms. Waveforms were derived from spectral Doppler signals and corrected for intrinsic spectral broadening errors by applying a previously published algorithm. The method was tested in a canine aneurysm model by determining velocities in small arteries (3-4 mm diameter) near the aneurysm where there was moderately disturbed flow. Doppler results were compared to velocity measurements in the same arteries acquired with a rapid volumetric phase contrast MR Angiography technique named PC-VIPR MRA. After correcting for intrinsic spectral broadening, there was a high degree of correlation between velocities obtained by the real-time UD and the accelerated PC-MRA technique. The peak systolic velocity yielded a linear correlation coefficient of r= 0.83; end diastolic velocity resulted in r= 0.81; and temporally-averaged mean velocity resulted in r= 0.76. The overall velocity waveforms obtained by the two techniques were also highly correlated (r=0.89 ± 0.06). There were, however, only weak correlations for the pulsatility index (PI; 0.25) and resistive index (RI; 0.14) derived from the two techniques. Results demonstrate that to avoid overestimations of peak systolic velocities, the results for UD must be carefully corrected to compensate for errors caused by intrinsic spectral broadening. PMID:21346280

  18. Registration of three-dimensional compound ultrasound scans of the breast for refraction and motion correction.

    PubMed

    Moskalik, A; Carson, P L; Meyer, C R; Fowlkes, J B; Rubin, J M; Roubidoux, M A

    1995-01-01

    Use of multiple look directions, that is, compound imaging, has been shown previously to increase detection of specular reflectors and averaging of speckle noise in gray-scale images, often at the expense of spatial resolution and other misregistration errors. In color flow imaging, additional view angles can fill in vessels missed due to Doppler angle dropout and increase quantitative and visual Doppler accuracy by triangulation or a simple peak-frequency-shift combination algorithm. Image registration and unwarping throughout multiple three-dimensional (3D) volume sets should correct for many refraction artifacts, motion between and during compounded image sets and even, possibly, positioning errors between image sets, acquired months apart, to display growth of abnormalities. The registration described here does not provide sufficient accuracy for formation of enhanced coherent apertures, but shows promise in some cases to provide superior compound images and possibly comparisons of current and prior studies. In this study, the breast is stabilized by mild compression between a flat plate and a scanning membrane. Registration and unwarping is performed retrospectively on two separate volumetric data sets by defining pairs of corresponding points and, in some cases, line and plane segments. Three-dimensional linear affine transforms are performed using identified points, lines and planes. 3D nonlinear warped transforms are also possible given adequate numbers of identifiable points. More than two data sets are registered by selecting one as the standard, and registering the remainder to match. The most appropriate algorithm, such as averaging or maximum amplitude, may be used to combine the data sets for display. Significant success has been achieved in compound display of a test object and of the breast in vivo, even when there was relative motion or warping between image sets. In pulse-echo imaging, homologous feature registration for compounding appears to

  19. Abdominal Ultrasound

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  20. Musculoskeletal Ultrasound

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  1. Ultrasound - Breast

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  2. Hip Ultrasound

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  3. Ultrasound - Scrotum

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  4. Obstetrical Ultrasound

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  5. Ultrasound -- Pelvis

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  6. Prostate Ultrasound

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  7. Cranial Ultrasound/Head Ultrasound

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  8. Automated kidney detection for 3D ultrasound using scan line searching

    NASA Astrophysics Data System (ADS)

    Noll, Matthias; Nadolny, Anne; Wesarg, Stefan

    2016-04-01

    Ultrasound (U/S) is a fast and non-expensive imaging modality that is used for the examination of various anatomical structures, e.g. the kidneys. One important task for automatic organ tracking or computer-aided diagnosis is the identification of the organ region. During this process the exact information about the transducer location and orientation is usually unavailable. This renders the implementation of such automatic methods exceedingly challenging. In this work we like to introduce a new automatic method for the detection of the kidney in 3D U/S images. This novel technique analyses the U/S image data along virtual scan lines. Here, characteristic texture changes when entering and leaving the symmetric tissue regions of the renal cortex are searched for. A subsequent feature accumulation along a second scan direction produces a 2D heat map of renal cortex candidates, from which the kidney location is extracted in two steps. First, the strongest candidate as well as its counterpart are extracted by heat map intensity ranking and renal cortex size analysis. This process exploits the heat map gap caused by the renal pelvis region. Substituting the renal pelvis detection with this combined cortex tissue feature increases the detection robustness. In contrast to model based methods that generate characteristic pattern matches, our method is simpler and therefore faster. An evaluation performed on 61 3D U/S data sets showed, that in 55 cases showing none or minor shadowing the kidney location could be correctly identified.

  9. Scanning Laser Doppler Vibrometer Measurements Inside Helicopter Cabins in Running Conditions: Problems and Mock-up Testing

    SciTech Connect

    Revel, G. M.; Castellini, P.; Chiariotti, P.; Tomasini, E. P.; Cenedese, F.; Perazzolo, A.

    2010-05-28

    The present work deals with the analysis of problems and potentials of laser vibrometer measurements inside helicopter cabins in running conditions. The paper describes the results of a systematic measurement campaign performed on an Agusta A109MKII mock-up. The aim is to evaluate the applicability of Scanning Laser Doppler Vibrometer (SLDV) for tests in simulated flying conditions and to understand how performances of the technique are affected when the laser head is placed inside the cabin, thus being subjected to interfering inputs. Firstly a brief description of the performed test cases and the used measuring set-ups are given. Comparative tests between SLDV and accelerometers are presented, analyzing the achievable performances for the specific application. Results obtained measuring with SLDV placed inside the helicopter cabin during operative excitation conditions are compared with those performed with the laser lying outside the mock-up, these last being considered as 'reference measurements'. Finally, in order to give an estimate of the uncertainty level on measured signals, a study linking the admitted percentage of noise content on vibrometer signals due to laser head vibration levels will be introduced.

  10. Scanning Laser Doppler Vibrometer Measurements Inside Helicopter Cabins in Running Conditions: Problems and Mock-up Testing

    NASA Astrophysics Data System (ADS)

    Revel, G. M.; Castellini, P.; Chiariotti, P.; Tomasini, E. P.; Cenedese, F.; Perazzolo, A.

    2010-05-01

    The present work deals with the analysis of problems and potentials of laser vibrometer measurements inside helicopter cabins in running conditions. The paper describes the results of a systematic measurement campaign performed on an Agusta A109MKII mock-up. The aim is to evaluate the applicability of Scanning Laser Doppler Vibrometer (SLDV) for tests in simulated flying conditions and to understand how performances of the technique are affected when the laser head is placed inside the cabin, thus being subjected to interfering inputs. Firstly a brief description of the performed test cases and the used measuring set-ups are given. Comparative tests between SLDV and accelerometers are presented, analyzing the achievable performances for the specific application. Results obtained measuring with SLDV placed inside the helicopter cabin during operative excitation conditions are compared with those performed with the laser lying outside the mock-up, these last being considered as "reference measurements". Finally, in order to give an estimate of the uncertainty level on measured signals, a study linking the admitted percentage of noise content on vibrometer signals due to laser head vibration levels will be introduced.

  11. Study on Water Distribution Imaging in the Sand Using Propagation Velocity of Sound with Scanning Laser Doppler Vibrometer

    NASA Astrophysics Data System (ADS)

    Sugimoto, Tsuneyoshi; Nakagawa, Yutaka; Shirakawa, Takashi; Sano, Motoaki; Ohaba, Motoyoshi; Shibusawa, Sakae

    2013-07-01

    We propose a method for the monitoring and imaging of the water distribution in the rooting zone of plants using sound vibration. In this study, the water distribution measurement in the horizontal and vertical directions in the soil layer was examined to confirm whether a temporal change in the volume water content of the soil could be estimated from a temporal changes in propagation velocity. A scanning laser Doppler vibrometer (SLDV) is used for measurement of the vibration velocity of the soil surface, because the highly precise vibration velocity measurement of several many points can be carried out automatically. Sand with a uniform particle size distribution is used for the soil, as it has high plasticity; that is, the sand can return to a dry state easily even if it is soaked with water. A giant magnetostriction vibrator or a flat speaker is used as a sound source. Also, a soil moisture sensor, which measures the water content of the soil using the electric permittivity, is installed in the sand. From the experimental results of the vibration measurement and soil moisture sensors, we can confirm that the temporal changes of the water distribution in sand using the negative pressure irrigation system in both the horizontal and vertical directions can be estimated using the propagation velocity of sound. Therefore, in the future, we plan to develop an insertion-type sound source and receiver using the acceleration sensors, and we intend to examine whether our method can be applied even in commercial soil with growing plants.

  12. A 3D ultrasound scanning system for image guided liver interventions.

    PubMed

    Neshat, Hamid; Cool, Derek W; Barker, Kevin; Gardi, Lori; Kakani, Nirmal; Fenster, Aaron

    2013-11-01

    Two-dimensional ultrasound (2D US) imaging is commonly used for diagnostic and intraoperative guidance of interventional liver procedures; however, 2D US lacks volumetric information that may benefit interventional procedures. Over the past decade, three-dimensional ultrasound (3D US) has been developed to provide the missing spatial information. 3D US image acquisition is mainly based on mechanical, electromagnetic, and freehand tracking of conventional 2D US transducers, or 2D array transducers available on high-end machines. These approaches share many problems during clinical use for interventional liver imaging due to lack of flexibility and compatibility with interventional equipment, limited field-of-view (FOV), and significant capital cost compared to the benefits they introduce. In this paper, a novel system for mechanical 3D US scanning is introduced to address these issues. The authors have developed a handheld mechanical 3D US system that incorporates mechanical translation and tilt sector sweeping of any standard 2D US transducer to acquire 3D images. Each mechanical scanning function can be operated independently or may be combined to allow for a hybrid wide FOV acquisition. The hybrid motion mode facilitates registration of other modalities (e.g., CT or MRI) to the intraoperative 3D US images by providing a larger FOV in which to acquire anatomical information. The tilting mechanism of the developed mover allows image acquisition in the intercostal rib space to avoid acoustic shadowing from bone. The geometric and volumetric scanning validity of the 3D US system was evaluated on tissue mimicking US phantoms for different modes of operation. Identical experiments were performed on a commercially available 3D US system for direct comparison. To replicate a clinical scenario, the authors evaluated their 3D US system by comparing it to CT for measurement of angle and distance between interventional needles in different configurations, similar to those

  13. Phentolamine re-dosing during penile dynamic colour Doppler ultrasound: a practical method to abolish a false diagnosis of venous leakage in patients with erectile dysfunction.

    PubMed

    Gontero, P; Sriprasad, S; Wilkins, C J; Donaldson, N; Muir, G H; Sidhu, P S

    2004-11-01

    Increased sympathetic tone may cause an equivocal response to a prostaglandin E1 (PGE1) penile Doppler ultrasound (US) examination interpreted as a venous leak. We evaluated the US parameters and erectile response to the addition of phentolamine to a PGE1 penile Doppler US examination to ascertain whether addition of phentolamine would abolish a suboptimal response. 32 patients (median age 29 years, range 17-70 years) with either a previous Doppler US pattern of venous leakage or a clinical suspicion of venogenic impotence, underwent Doppler US after a total dose of 20 microg of PGE1. Peak systolic velocity (PSV), end diastolic velocity (EDV) and grade of erection were documented. If erectile response was suboptimal irrespective of the EDV measurement, 2 mg-intracavernosal phentolamine was administered and measurements repeated. Six patients had a normal erectile response, the remaining 26 received phentolamine. A significant increase in PSV between baseline and 20 microg PGE1 (p<0.001) was observed in all cases. Following phentolamine there was a significant increase in grade of erection (p=0.0001) and a significant reduction in the EDV (p=0.0001). A reduction of the EDV to below 0.0 cm s(-1) was observed in 16 patients. Four patients with EDV <5.0 cm s(-1) but >0.0 cm s(-1) had improved erectile response following phentolamine while six showed persistent EDV elevation >5 cm s(-1). No priapism was documented. It is essential to ensure cavernosal relaxation using phentolamine before a Doppler US diagnosis of venous leak is made. This two-stage assessment will allow this to be done efficiently and with a low risk of priapism.

  14. Improved cardiac motion detection from ultrasound images using TDIOF: a combined B-mode/ tissue Doppler approach

    NASA Astrophysics Data System (ADS)

    Tavakoli, Vahid; Stoddard, Marcus F.; Amini, Amir A.

    2013-03-01

    Quantitative motion analysis of echocardiographic images helps clinicians with the diagnosis and therapy of patients suffering from cardiac disease. Quantitative analysis is usually based on TDI (Tissue Doppler Imaging) or speckle tracking. These methods are based on two independent techniques - the Doppler Effect and image registration, respectively. In order to increase the accuracy of the speckle tracking technique and cope with the angle dependency of TDI, herein, a combined approach dubbed TDIOF (Tissue Doppler Imaging Optical Flow) is proposed. TDIOF is formulated based on the combination of B-mode and Doppler energy terms in an optical flow framework and minimized using algebraic equations. In this paper, we report on validations with simulated, physical cardiac phantom, and in-vivo patient data. It is shown that the additional Doppler term is able to increase the accuracy of speckle tracking, the basis for several commercially available echocardiography analysis techniques.

  15. Physiological aspects of the determination of comprehensive arterial inflows in the lower abdomen assessed by Doppler ultrasound

    PubMed Central

    2012-01-01

    Non-invasive measurement of splanchnic hemodynamics has been utilized in the clinical setting for diagnosis of gastro-intestinal disease, and for determining reserve blood flow (BF) distribution. However, previous studies that measured BF in a "single vessel with small size volume", such as the superior mesenteric and coeliac arteries, were concerned solely with the target organ in the gastrointestinal area, and therefore evaluation of alterations in these single arterial BFs under various states was sometimes limited to "small blood volumes", even though there was a relatively large change in flow. BF in the lower abdomen (BFAb) is potentially a useful indicator of the influence of comprehensive BF redistribution in cardiovascular and hepato-gastrointestinal disease, in the postprandial period, and in relation to physical exercise. BFAb can be determined theoretically using Doppler ultrasound by subtracting BF in the bilateral proximal femoral arteries (FAs) from BF in the upper abdominal aorta (Ao) above the coeliac trunk. Prior to acceptance of this method of determining a true BFAb value, it is necessary to obtain validated normal physiological data that represent the hemodynamic relationship between the three arteries. In determining BFAb, relative reliability was acceptably high (range in intra-class correlation coefficient: 0.85-0.97) for three arterial hemodynamic parameters (blood velocity, vessel diameter, and BF) in three repeated measurements obtained over three different days. Bland-Altman analysis of the three repeated measurements revealed that day-to-day physiological variation (potentially including measurement error) was within the acceptable minimum range (95% of confidence interval), calculated as the difference in hemodynamics between two measurements. Mean BF (ml/min) was 2951 ± 767 in Ao, 316 ± 97 in left FA, 313 ± 83 in right FA, and 2323 ± 703 in BFAb, which is in agreement with a previous study that measured the sum of BF in the major

  16. Seminal, clinical and colour-Doppler ultrasound correlations of prostatitis-like symptoms in males of infertile couples.

    PubMed

    Lotti, F; Corona, G; Mondaini, N; Maseroli, E; Rossi, M; Filimberti, E; Noci, I; Forti, G; Maggi, M

    2014-01-01

    'Prostatitis-like symptoms' (PLS) are a cluster of bothersome conditions defined as 'perineal and/or ejaculatory pain or discomfort and National Institutes of Health-Chronic Prostatitis Symptom Index (NIH-CPSI) pain subdomain score ≥4' (Nickel's criteria). PLS may originate from the prostate or from other portions of the male genital tract. Although PLS could be associated with 'prostatitis', they should not be confused. The NIH-CPSI is considered the gold-standard for assessing PLS severity. Although previous studies investigated the impact of prostatitis, vesiculitis or epididymitis on semen parameters, correlations between their related symptoms and seminal or scrotal/transrectal colour-Doppler ultrasound (CDU) characteristics have not been carefully determined. And no previous study evaluated the CDU features of PLS in infertile men. This study was aimed at investigating possible associations among NIH-CPSI (total and subdomain) scores and PLS, with seminal, clinical and scrotal/transrectal CDU parameters in a cohort of males of infertile couples. PLS of 400 men (35.8 ± 7.2 years) with a suspected male factor were assessed by the NIH-CPSI. All patients underwent, during the same day, semen analysis, seminal plasma interleukin 8 (sIL-8, a marker of male genital tract inflammation), biochemical evaluation, urine/seminal cultures, scrotal/transrectal CDU. PLS was detected in 39 (9.8%) subjects. After adjusting for age, waist and total testosterone (TT), no association among NIH-CPSI (total or subdomain) scores or PLS and sperm parameters was observed. However, we found a positive association with current positive urine and/or seminal cultures, sIL-8 levels and CDU features suggestive of inflammation of the epididymis, seminal vesicles, prostate, but not of the testis. The aforementioned significant associations of PLS were further confirmed by comparing PLS patients with age-, waist- and TT-matched PLS-free patients (1 : 3 ratio). In conclusion, NIH

  17. Renal imaging: a comparison of radionuclide, ultrasound, and computed tomographic scanning in investigation of renal space-occupying lesions.

    PubMed Central

    O'Reilly, P H; Osborn, D E; Testa, H J; Asbury, D L; Best, J J; Barnard, R J

    1981-01-01

    Two studies were carried out in which 27 and 23 patients respectively with renal space-occupying lesions were assessed by different techniques and the results compared. Instead of proceeding to renal arteriography after the lesion had been found on urography, radionuclide and ultrasound scanning were used in the first study to clarify the nature of the lesions, while in the second study computed tomography was used as well. Results were good with all three methods, although ultrasonography and radionuclide scanning cannot resolve lesions of under 2 cm in diameter and the radiation dose with computed tomography is similar to that used in renal arteriography. Probably the best method of evaluating renal space-occupying lesions after urography is to use both ultrasound and radionuclide scanning. If further information is required computed tomography or arteriography is indicated. PMID:6781661

  18. The detection of microemboli in the middle cerebral artery during cardiopulmonary bypass: a transcranial Doppler ultrasound investigation using membrane and bubble oxygenators.

    PubMed

    Padayachee, T S; Parsons, S; Theobold, R; Linley, J; Gosling, R G; Deverall, P B

    1987-09-01

    Twenty-seven patients were examined who were undergoing cardiopulmonary bypass (CPB) surgery with either a bubble oxygenator or a capillary membrane oxygenator. The latter incorporated an arterial filter and bubble trap. A noninvasive Doppler ultrasound technique is described for monitoring irregularities in the Doppler flow signals attributable to gaseous microemboli detected in the middle cerebral artery during CPB. The ultrasound index for detecting gaseous microemboli (MEI) indicated the presence of such microemboli in 22 of the 27 patients during insertion of the aortic cannula. Measurements during CPB showed the MEI ranged from 4 to 39 in the 17 patients with a bubble oxygenator. However, all 10 patients with a membrane oxygenator had an MEI of 0. Varying the gas flow rates in 3 patients with bubble oxygenators showed a change in MEI from 4 +/- 4 (SD) at a flow rate of 2 L/min to 17 +/- 9 at a flow rate of 5 L/min. This observation supports the assumption that the MEI is providing quantitative information regarding the presence of gaseous emboli in the middle cerebral artery.

  19. Non-Invasive Assessment of Fibrosis Using Color Doppler Ultrasound in Patients with Hepatitis C Virus in the Amazon Rainforest, Brazil

    PubMed Central

    Leão, Jorge; Brock, Marianna; Castilho, Márcia; Scariot, André; Scariot, Ana; Braga, Wornei

    2012-01-01

    The purpose of this study was to correlate morphologic and hemodynamic Doppler ultrasound findings as indicators of the degree of inflammation and fibrosis and to diagnose chronic vital hepatitis complications and progression. A prospective, descriptive study of a case series was conducted that analyzed Doppler ultrasound images of the liver and portal system and used the portal vein congestion index, hepatic and splenic artery impedance indices, and the liver vascular index. Of 50 patients positive for antibodies against hepatitis C virus, morphologic changes highlighted increased hepatic parenchyma echogenicity in 24%, and increased gall blander echogenicity and wall thickness in 4%. The most common hemodynamic changes observed were reduced flow velocity in the portal vein trunk in 26%, congestion index changes in 12%, liver vascular index changes in 16%, and splenic and hepatic artery impedance index changes in 14%. These indices were shown to be associated with alanine aminotransferase levels, which suggested that they are important liver damage indicators in the early phase of infection with hepatitis C virus. PMID:22302863

  20. Can Doppler or contrast-enhanced ultrasound analysis add diagnostically important information about the nature of breast lesions?

    PubMed Central

    Stanzani, Daniela; Chala, Luciano F.; de Barros, Nestor; Cerri, Giovanni G.; Chammas, Maria Cristina

    2014-01-01

    OBJECTIVES: Despite evidence suggesting that Doppler ultrasonography can help to differentiate between benign and malignant breast lesions, it is rarely applied in clinical practice. The aim of this study was to determine whether certain vascular features of breast masses observed by duplex Doppler and color Doppler ultrasonography (before and/or after microbubble contrast injection) add information to the gray-scale analysis and support the Breast Imaging-Reporting and Data System (BI-RADS) classification. METHODS: Seventy solid lesions were prospectively evaluated with gray-scale ultrasonography, color Doppler ultrasonography, and contrast-enhanced ultrasonography. The morphological analysis and lesion vascularity were correlated with the histological results. RESULTS: Percutaneous core biopsies revealed that 25/70 (17.5%) lesions were malignant, while 45 were benign. Hypervascular lesions with tortuous and central vessels, a resistive index (RI)≥0.73 before contrast injection, and an RI≥0.75 after contrast injection were significantly predictive of malignancy (p<0.001). CONCLUSION: The combination of gray-scale ultrasonography data with unenhanced or enhanced duplex Doppler and color Doppler US data can provide diagnostically useful information. These techniques can be easily implemented because Doppler devices are already present in most health centers. PMID:24519198

  1. Comparison of the biometric formulas used for applanation A-scan ultrasound biometry.

    PubMed

    Özcura, Fatih; Aktaş, Serdar; Sağdık, Hacı Murat; Tetikoğlu, Mehmet

    2016-10-01

    The purpose of the study was to compare the accuracy of various biometric formulas for predicting postoperative refraction determined using applanation A-scan ultrasound. This retrospective comparative study included 485 eyes that underwent uneventful phacoemulsification with intraocular lens (IOL) implantation. Applanation A-scan ultrasound biometry and postoperative manifest refraction were obtained in all eyes. Biometric data were entered into each of the five IOL power calculation formulas: SRK-II, SRK/T, Holladay I, Hoffer Q, and Binkhorst II. All eyes were divided into three groups according to axial length: short (≤22.0 mm), average (22.0-25.0 mm), and long (≥25.0 mm) eyes. The postoperative spherical equivalent was calculated and compared with the predicted refractive error using each biometric formula. The results showed that all formulas had significantly lower mean absolute error (MAE) in comparison with Binkhorst II formula (P < 0.01). The lowest MAE was obtained with the SRK-II for average (0.49 ± 0.40 D) and short (0.67 ± 0.54 D) eyes and the SRK/T for long (0.61 ± 0.50 D) eyes. The highest postoperative hyperopic shift was seen with the SRK-II for average (46.8 %), short (28.1 %), and long (48.4 %) eyes. The highest postoperative myopic shift was seen with the Holladay I for average (66.4 %) and long (71.0 %) eyes and the SRK/T for short eyes (80.6 %). In conclusion, the SRK-II formula produced the lowest MAE in average and short eyes and the SRK/T formula produced the lowest MAE in long eyes. The SRK-II has the highest postoperative hyperopic shift in all eyes. The highest postoperative myopic shift is with the Holladay I for average and long eyes and SRK/T for short eyes.

  2. Ultrasound for diagnosis of carpal tunnel syndrome: comparison of different methods to determine median nerve volume and value of power Doppler sonography.

    PubMed

    Dejaco, Christian; Stradner, Martin; Zauner, Dorothea; Seel, Werner; Simmet, Nicole Elisabeth; Klammer, Alexander; Heitzer, Petra; Brickmann, Kerstin; Gretler, Judith; Fürst-Moazedi, Florentine C; Thonhofer, Rene; Husic, Rusmir; Hermann, Josef; Graninger, Winfried B; Quasthoff, Stefan

    2013-12-01

    To compare ultrasound measurement of median nerve cross-sectional area (CSA) at different anatomical landmarks and to assess the value of power Doppler signals within the median nerve for diagnosis of carpal tunnel syndrome (CTS). A prospective study of 135 consecutive patients with suspected CTS undergoing two visits within 3 months. A final diagnosis of CTS was established by clinical and electrophysiological findings. CSA was sonographically measured at five different levels at forearm and wrist; and CSA wrist to forearm ratios or differences were calculated. Intraneural power Doppler signals were semiquantitatively graded. Diagnostic values of different ultrasound methods were compared by receiver operating characteristic curves using SPSS. CTS was diagnosed in 111 (45.5%) wrists; 84 (34.4%) had no CTS and 49 (20.1%) were possible CTS cases. Diagnostic values were comparable for all sonographic methods to determine median nerve swelling, with area under the curves ranging from 0.75 to 0.85. Thresholds of 9.8 and 13.8 mm(2) for the largest CSA of the median nerve yielded a sensitivity of 92% and a specificity of 92%. A power Doppler score of 2 or greater had a specificity of 90% for the diagnosis of CTS. Sonographic median nerve volumetry revealed a good reliability with an intraclass correlation coefficient of 0.90 (95% CI 0.79 to 0.95). Sonographic assessment of median nerve swelling and vascularity allows for a reliable diagnosis of CTS. Determination of CSA at its maximal shape offers an easily reproducible tool for CTS classification in daily clinical practice.

  3. Ultrasound Annual, 1984

    SciTech Connect

    Sanders, R.C.; Hill, M.C.

    1984-01-01

    The 1984 edition of Ultrasound Annual explores new applications of ultrasound in speech and swallowing and offers guidelines on the use of ultrasound and nuclear medicine in thyroid and biliary tract disease. Other areas covered include Doppler sonography of the abdomen, intraoperative abdominal ultrasound, sonography of the placenta, ultrasound of the neonatal head and abdomen, and sonographic echo patterns created by fat.

  4. Quantification of blood flow in the carotid arteries: comparison of Doppler ultrasound and three different phase-contrast magnetic resonance imaging sequences.

    PubMed

    Seitz, J; Strotzer, M; Wild, T; Nitz, W R; Völk, M; Lenhart, M; Feuerbach, S

    2001-11-01

    To compare blood flow velocities in the carotid arteries measured with three different magnetic resonance (MR) phase-contrast imaging techniques and with percutaneous Doppler ultrasound. Fourteen healthy male volunteers with a mean age of 33 +/- 3.8 y