Causes of Ultrasound Doppler Twinkling Artifact

NASA Astrophysics Data System (ADS)

Leonov, D. V.; Kulberg, N. S.; Gromov, A. I.; Morozov, S. P.; Kim, S. Yu.

2018-01-01

Ultrasound Doppler twinkling artifact is analyzed. It usually appears as a frequent color alteration in the region of hyperechoic objects. Its noiselike spectrum can also be seen in spectral Doppler mode. Physicians use twinkling artifact as a clinical sign for kidney-stone and soft-tissue calculi detection. The advantageous peculiarity of this study is that the experiments were conducted utilizing raw signals obtained from a custom ultrasonic machine and a specially developed phantom. The phantom contained specimens with known qualities, allowing for reproducible and predictable results. The experiments revealed evidence for two physical causes of twinkling artifact, which were associated with two unique Doppler signals. The research laid the foundation for the new reflected-signal model introduced and used throughout this paper.

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

Doppler ultrasound to detect pulpal blood flow changes during local anaesthesia.

PubMed

Yoon, M J; Lee, S J; Kim, E; Park, S H

2012-01-01

  To examine whether Doppler ultrasound can detect changes in pulpal blood flow after infiltration anaesthesia.   Changes in pulpal blood flow in maxillary central incisor teeth of 18 patients (mean age 26.7 years, 13 men, five women) after infiltration anaesthesia were examined. Before infiltration anaesthesia, the pulpal blood flow was measured using Doppler ultrasound. A local anaesthetic solution containing 2% lidocaine with 1:80,000 epinephrine was injected into the submucosa above the experimental tooth. The Doppler ultrasound test was carried out at 5, 10, 20, 30, 45 and 60 min after infiltration. The parameters were Vas (maximum linear velocity, cm s(-1) ), Vam (average linear velocity, cm s(-1) ) and Vakd (minimum linear velocity, cm s(-1) ), which are indicators of the level of blood flow. The mixed procedure at the 95% confidence interval was used to examine the changes in pulpal blood flow after the injection.   The linear velocity profiles (Vas, Vam, and Vakd) decreased sharply 5 min after anaesthesia and then reduced continuously for 30 min. The maximum degree of blood flow reduction in Vas, Vam and Vakd was 58%, 83% and 82%, respectively. After 30 min, the linear velocities increased gradually. The Vam returned to the pre-anaesthesia state at 60 minutes but the Vas and Vakd did not recover completely.   Doppler ultrasound can detect changes in pulpal blood flow after infiltration anaesthesia. In the future, Doppler ultrasound can be used as a tool for measuring pulpal blood flow. © 2011 International Endodontic Journal.

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.

Ultrasound Doppler method of remote elastometry

NASA Astrophysics Data System (ADS)

Timanin, E. M.; Eremin, E. V.; Belyaev, R. V.; Mansfel'd, A. D.

2015-03-01

The paper presents the theoretical relations constituting the basis of remote measurements of the shear elasticity of biological tissues using the ultrasound Doppler method. It also describes the hardware-software setup implementing this approach, as well as the results of experiments with these tools on a biological tissue phantom and on human liver in vivo.

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

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

[The use of intraoperative Doppler ultrasound in endoscopic transsphenoidal surgery].

PubMed

Sharipov, O I; Kutin, M A; Kalinin, P L; Fomichev, D V; Lukshin, V A; Kurnosov, A B

2016-01-01

Doppler ultrasound (DUS) has been widely used in neurosurgical practice to diagnose various cerebrovascular diseases. This technique is used in transsphenoidal surgery to identify the localization of intracranial arteries when making an approach or during tumor resection. To identify the cavernous segment of the internal carotid artery (ICA) and/or basilar artery during endoscopic transsphenoidal surgery, we used a combined device on the basis of a click line curette («Karl Storz») and a 16 MHz Doppler probe (Lassamed). The technique was used in 51 patients during both standard transsphenoidal surgery (23 cases) and transsphenoidal tumor resection through an extended approach (28 cases). Doppler ultrasound was used in different situations: to determine a trajectory of the endonasal transsphenoidal approach in the absence of the normal anatomical landmarks (16 cases), to define the limits of safe resection of a tumor located in the laterosellar region (7), and to implement an extended transsphenoidal endoscopic approach (28). Intraoperative Doppler ultrasound enabled identification of the cavernous segment of the internal carotid artery in 45 cases and the basilar artery in 2 cases; a blood vessel was not found in 4 cases. Injury to the cavernous segment of the internal carotid artery was observed only in 1 case. The use of the described combined device in transsphenoidal surgery turned Doppler ultrasound into an important and useful technique for visualization of the ICA within the tumor stroma as well as in the case of the changed skull base anatomy. Its use facilitates manipulations in a deep and narrow wound and enables inspection of the entire surface of the operative field in various planes, thereby surgery becomes safer due to the possibility of maximum investigation of the operative field.

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

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

PubMed

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

2010-12-01

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

Design and implementation of a smartphone-based portable ultrasound pulsed-wave Doppler device for blood flow measurement.

PubMed

Huang, Chih-Chung; Lee, Po-Yang; Chen, Pay-Yu; Liu, Ting-Yu

2012-01-01

Blood flow measurement using Doppler ultrasound has become a useful tool for diagnosing cardiovascular diseases and as a physiological monitor. Recently, pocket-sized ultrasound scanners have been introduced for portable diagnosis. The present paper reports the implementation of a portable ultrasound pulsed-wave (PW) Doppler flowmeter using a smartphone. A 10-MHz ultrasonic surface transducer was designed for the dynamic monitoring of blood flow velocity. The directional baseband Doppler shift signals were obtained using a portable analog circuit system. After hardware processing, the Doppler signals were fed directly to a smartphone for Doppler spectrogram analysis and display in real time. To the best of our knowledge, this is the first report of the use of this system for medical ultrasound Doppler signal processing. A Couette flow phantom, consisting of two parallel disks with a 2-mm gap, was used to evaluate and calibrate the device. Doppler spectrograms of porcine blood flow were measured using this stand-alone portable device under the pulsatile condition. Subsequently, in vivo portable system verification was performed by measuring the arterial blood flow of a rat and comparing the results with the measurement from a commercial ultrasound duplex scanner. All of the results demonstrated the potential for using a smartphone as a novel embedded system for portable medical ultrasound applications. © 2012 IEEE

Three-dimensional color Doppler imaging of the carotid artery

NASA Astrophysics Data System (ADS)

Picot, Paul A.; Rickey, Daniel W.; Mitchell, Ross; Rankin, Richard N.; Fenster, Aaron

1991-05-01

Stroke is the third leading cause of death in the United States. It is caused by ischemic injury to the brain, usually resulting from emboli from atherosclerotic plaques. The carotid bifurcation in humans is prone to atherosclerotic disease and is a site where emboli may originate. Currently, carotid stenoses are evaluated by non-invasive duplex Doppler ultrasound, with preoperative verification by intra-arterial angiography. We have developed a system that uses a color Doppler ultrasound imaging system to acquire in-vivo 3-D color Doppler images of the human carotid artery, with the aim of increasing the diagnostic accuracy of ultrasound and decreasing the use of angiography for verification. A clinical TL Ultramark 9 color Doppler ultrasound system was modified by mounting the hand-held ultrasound scan head on a motor-driven translation stage. The stage allows planar ultrasound images to be acquired over 45 mm along the neck between the clavicle and the mandible. A 3- D image is acquired by digitizing, in synchrony with the cardiac cycle, successive color ultrasound video images as the scan head is stepped along the neck. A complete volume set of 64 frames, comprising some 15 megabytes of data, requires approximately 2 minutes to acquire. The volume image is reformatted and displayed on a Sun 4/360 workstation equipped with a TAAC-1 graphics accelerator. The 3-D image may be manipulated in real time to yield the best view of blood flow in the bifurcation.

Obstetric Ultrasound

PubMed Central

Nicholson, Stuart F.; Nimrod, Carl A.

1988-01-01

This article addresses the current indications for an obstetric ultrasound and describes the findings that it is reasonable to expect when reading an ultrasound report. The authors discuss several common obstetrical problems focussing the attention on the usefulness of the imaging information. Finally, they provide a glimpse into the future direction of obstetric ultrasound by discussing vaginal scanning, Doppler assessment of fetal blood flow, and routine ultrasound in pregnancy. PMID:21253229

Etiology of congenital hypothyroidism using thyroglobulin and ultrasound combination.

PubMed

Beltrão, Cristine B; Juliano, Adriana G; Chammas, Maria C; Watanabe, Tomoco; Sapienza, Marcelo T; Marui, Suemi

2010-01-01

Methods currently employed to establish the etiology of congenital hypothyroidism include thyroid ultrasound and scintigraphic exams. Thyroglobulin is a protein almost exclusively secreted by thyroid tissue and indirectly reflects the amount of follicular cells. Even though thyroglobulin is easy to measure, it has been not frequently used because of discordant results to distinguish mainly athyreosis and ectopy (dysgenesis). Knowing the differences in inheritance and prognosis of thyroid dysgenesis and dyshormonogenesis, it is important to define the etiology of CH, combining tools that are easy, fast and available in most medical centers. Our objective was to evaluate and compare color Doppler ultrasound and serum thyroglobulin with radionuclide scan to define the etiology of congenital hypothyroidism. We evaluated 38 children above 3 years-old off-treatment that performed serum thyroglobulin by immunofluorometric assay, color Doppler ultrasound and radionuclide study. On color Doppler ultrasound, 11 patients had athyreosis, 5 ectopic glands, being 1 associated to hemiagenesis. Twenty one had topic thyroid (3 goiters, 10 normal, 8 hypoplastic). Hemiagenesis and cystic lesion were not revealed by radionuclide scan. We observed substantial agreement between color Doppler ultrasound and radionuclide scan (kappa=0.745, p<0.0001). Serum thyroglobulin in athyreosis ranged from <1.0 to 18.7 micro g/L. Patients with ectopic glands showed wider thyroglobulin range (4.5 to 123 micro g/L, median 28.4 micro g/L). Only one patient showed thyroglobulin deficiency. By using color Doppler ultrasound and serum thyroglobulin levels as valuable combined tools, we established the etiology of congenital hypothyroidism limiting excessive and harmful exams in children, like radionuclide scan.

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.

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.

Audible handheld Doppler ultrasound determines reliable and inexpensive exclusion of significant peripheral arterial disease.

PubMed

Alavi, Afsaneh; Sibbald, R Gary; Nabavizadeh, Reza; Valaei, Farnaz; Coutts, Pat; Mayer, Dieter

2015-12-01

To determine the accuracy of audible arterial foot signals with an audible handheld Doppler ultrasound for identification of significant peripheral arterial disease as a simple, quick, and readily available bedside screening tool. Two hundred consecutive patients referred to an interprofessional wound care clinic underwent audible handheld Doppler ultrasound of both legs. As a control and comparator, a formal bilateral lower leg vascular study including the calculation of Ankle Brachial Pressure Index and toe pressure (TP) was performed at the vascular lab. Diagnostic reliability of audible handheld Doppler ultrasound was calculated versus Ankle Brachial Pressure Index as the gold standard test. A sensitivity of 42.8%, a specificity of 97.5%, negative predictive value of 94.10%, positive predictive value of 65.22%, positive likelihood ratio of 17.52, and negative likelihood ratio of 0.59. The univariable logistic regression model had an area under the curve of 0.78. There was a statistically significant difference at the 5% level between univariable and multivariable area under the curves of the dorsalis pedis and posterior tibial models (p < 0.001). Audible handheld Doppler ultrasound proved to be a reliable, simple, rapid, and inexpensive bedside exclusion test of peripheral arterial disease in diabetic and nondiabetic patients. © The Author(s) 2015.

The effect of blood acceleration on the ultrasound power Doppler spectrum

NASA Astrophysics Data System (ADS)

Matchenko, O. S.; Barannik, E. A.

2017-09-01

The purpose of the present work was to study the influence of blood acceleration and time window length on the power Doppler spectrum for Gaussian ultrasound beams. The work has been carried out on the basis of continuum model of the ultrasound scattering from inhomogeneities in fluid flow. Correlation function of fluctuations has been considered for uniformly accelerated scatterers, and the resulting power Doppler spectra have been calculated. It is shown that within the initial phase of systole uniformly accelerated slow blood flow in pulmonary artery and aorta tends to make the correlation function about 4.89 and 7.83 times wider, respectively, than the sensitivity function of typical probing system. Given peak flow velocities, the sensitivity function becomes, vice versa, about 4.34 and 3.84 times wider, respectively, then the correlation function. In these limiting cases, the resulting spectra can be considered as Gaussian. The optimal time window duration decreases with increasing acceleration of blood flow and equals to 11.62 and 7.54 ms for pulmonary artery and aorta, respectively. The width of the resulting power Doppler spectrum is shown to be defined mostly by the wave vector of the incident field, the duration of signal and the acceleration of scatterers in the case of low flow velocities. In the opposite case geometrical properties of probing field and the average velocity itself are more essential. In the sense of signal-noise ratio, the optimal duration of time window can be found. Abovementioned results may contribute to the improved techniques of Doppler ultrasound diagnostics of cardiovascular system.

[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.

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.

Color Doppler ultrasound evaluation of testicular blood flow in stallions.

PubMed

Pozor, M A; McDonnell, S M

2004-04-01

The objectives of this study were to evaluate the potential use of color Doppler ultrasound to characterize blood flow to the stallion testis, and to establish reference values for Doppler measures of blood flow in the testicular artery of the stallion. Both testes from each of 52 horses were examined using a pulsed-wave color Doppler ultrasound with a sector array 5/7.5 MHz transducer with a 1mm gate setting. Peak systolic velocity (PSV), end diastolic velocity (EDV), resistive index (RI), and pulsatility index (PI) of the testicular artery were measured in each of two locations, the convoluted aspect (spermatic cord) and the marginal aspect of the artery (on the epididymal edge of testis). We found that: (1) all measures were obtainable; (2) except for EDV, the majority of the measures were higher at the cord location than at the marginal aspect of the artery (P < 0.05); and (3) measures for left and right testes were similar (P > 0.10). Resulting measures from 41 of these stallions (82 testes) that appeared free of testicular pathology provide useful reference values for clinical evaluation. Evaluation of 11 cases with testicular pathology suggested further investigation of possible effects of these various conditions on testicular blood flow and testicular function.

[Validation of a new hand-carried ultrasound device equipped with directional color power Doppler and continuous wave Doppler].

PubMed

Kawai, Junichi; Tanabe, Kazuaki; Matsuzaki, Masashi; Yamaguchi, Kazuto; Yagi, Toshikazu; Fujii, Yoko; Konda, Toshiko; Ui, Kazuyo; Sumida, Toshiaki; Okada, Midori; Tani, Tomoko; Morioka, Shigefumi

2003-10-01

This study evaluated the accuracy of the directional color power Doppler (DCPD) and continuous wave Doppler (CWD) methods incorporated in the new hand-carried SonoSite 180PLUS ultrasound device. The hand-held ultrasound system with 2.5 MHz transducer and SONOS 5500 was used as a standard ultrasound system with a 2 to 4 MHz wideband transducer. The experimental study used a Doppler wire phantom to evaluate the influence of target wire speed and angle of transducer on DCPD imaging. The clinical study included 48 consecutive patients. DCPD assessment of valvular regurgitation measured the distances of DCPD signals of mitral, aortic and tricuspid valve regurgitation using the apical four-chamber view for comparison with standard echocardiography. CWD assessment measured the peak velocities of the aortic flow and tricuspid valve regurgitant flow for comparison with standard echocardiography. In the experimental study, DCPD signals were not influenced by target wire speed changes and transducer incident angles. In the clinical study, agreements for mitral, aortic and tricuspid regurgitation between the two methods were 89.6%, 81.8% and 78.7%, respectively. The distances of DCPD valve regurgitant signals by the hand-carried ultrasound device showed good correlation (mitral regurgitation: y = 0.84x + 0.55; r = 0.93, aortic regurgitation: y = 0.95x + 0.27; r = 0.94, tricuspid regurgitation: y = 0.86x + 0.61; r = 0.90) with those by standard echocardiography. Evaluation of CWD velocity measurements showed good agreement for the lower flow velocities (< 2.0 m/sec). However, underestimation occurred for the high flow velocities (> 2.0 m/sec) compared with those by standard echocardiography (aortic flow: y = 0.80x + 0.11; r = 0.95, tricuspid regurgitation: y = 1.00x - 0.23; r = 0.90). The new hand-carried ultrasound device (SonoSite 180PLUS equipped with DCPD and CWD) is clinically useful for evaluating valvular regurgitations and flow velocities. Further studies are needed to

3D power Doppler ultrasound in early diagnosis of preeclampsia.

PubMed

Neto, R Moreira; Ramos, J G L

2016-01-01

Preeclampsia is a known cause of maternal, fetal and neonatal morbidity and mortality. Thus, evaluation of the predicting value of comparing 3D power Doppler indices (3DPD) of uteroplacental circulation (UPC) in the first and second trimester in patients who developed preeclampsia (PE) and those who did not and testing the hypothesis that the parameters of vascularization and placenta flow intensity, as determined by three-dimensional ultrasound (3D), are different in normal pregnancies compared with preeclampsia, could be a suitable screening method. A prospective observational study using 3D power Doppler were performed to evaluate the placental perfusion in 96 pregnant women who came to do the ultrasound routine between 11 and 14 weeks. The placental vascular index (VI), flow index (FI), blood vessels and blood flow index (VFI) by three-dimensional Doppler histogram were calculated. All patients repeated the exam between 16 and 20 weeks. The outcome was scored as normal or preeclamptic. Placental vascular indices including VI, FI and VFI were significantly lower in preeclamptic placentas compared with controls in the study performed in the second trimester (p<0.001). There was not any statistical difference in the patients examined in the first trimester. Our findings suggest that 3D-power Doppler assessment of placental vascular indices in the second trimester has the potential to detect women at risk for subsequent development of PE. Copyright © 2015 International Society for the Study of Hypertension in Pregnancy. Published by Elsevier B.V. All rights reserved.

Transcranial Doppler Ultrasound in Peninsular Arab Patients With Sickle Cell Disease.

PubMed

Adekile, Adekunle; Hassan, Meaad; Asbeutah, Akram; Al-Hinai, Mohamed; Trad, Omar; Farhan, Nayef

2018-05-06

Transcranial Doppler ultrasound is used to identify patients with sickle cell disease (SCD) at risk for stroke. We performed transcranial Doppler studies in patients from 4 countries in the Arabian Peninsula (Kuwait, Oman, Iraq, and United Arab Emirates) to document the prevalence of abnormal transcranial Doppler findings. The patients were recruited from outpatient clinics and studied in a steady state. Transcranial Doppler examinations were performed with standard equipment by experienced operators. The time-averaged maximum mean velocity (TAMMV) was documented in the arteries of the circle of Willis. The hemoglobin (Hb) genotype was confirmed, and the fetal Hb level and complete blood counts were determined. There were 415 patients in the study, aged 2 to 18 years (mean ± SD, 8.6 ± 3.5 years). None of the patients had an abnormal TAMMV (ie, > 200 cm/s), whereas only 13 (3.1%), all from Iraq, had conditional values (170-200 cm/s) in the right middle cerebral artery and 7 (1.7%) in the left middle cerebral artery. There were no consistent TAMMV differences among male and female patients or in patients with different Hb genotypes (sickle cell anemia, sickle cell β 0- thalassemia, and sickle D). The use of hydroxyurea was associated with a lower TAMMV, whereas a blood transfusion history had no influence. Total hemoglobin, reticulocyte count, serum bilirubin, and fetal Hb values showed varying degrees of association with the TAMMV in the different vessels. This study has demonstrated the rarity of abnormal transcranial Doppler findings among Peninsular Arab patients with SCD. The guidelines for transcranial Doppler screening in this population need further studies and recommendations. © 2018 by the American Institute of Ultrasound in Medicine.

Scanned focussed ultrasound hyperthermia: initial clinical results.

PubMed

Shimm, D S; Hynynen, K H; Anhalt, D P; Roemer, R B; Cassady, J R

1988-11-01

Between November 1986 and July, 1987, a preliminary study to determine the feasibility of scanned focussed ultrasound for clinical hyperthermia at various sites was conducted. Fourteen patient (17 tumors) have been treated using a microprocessor-controlled apparatus developed at the University of Arizona by modifying a commercially available diagnostic ultrasound unit. We have treated nine pelvic tumors, four extremity tumors, two brain tumors, and two extracranial head and neck tumors for a total of 42 treatments. Multipoint thermometry was achieved for all patients, with 2-25 (mean = 10) points monitored during each treatments within the scanned tumor volume. Average maximum temperature within the scanned tumor volume was 44.2, 44.7, 44.8, and 42.0 degrees C for pelvic, extremity brain, and extracranial head and neck tumors, respectively; similarly, 55%, 45%, 71%, and 0 of monitored points exceeded 42.5 degrees C. Pain limited applied power in 15 of 42 treatments, and bone pain with a periodicity similar to the scanning periodicity was seen in 11 treatments. A non-randomized comparison of temperatures achieved using scanned focussed ultrasound to those achieved using the microwave annular array and the CDRH Helix suggests that scanned focussed ultrasound may have promise and potential advantages in heating selected pelvic tumors.

A method to validate quantitative high-frequency power doppler ultrasound with fluorescence in vivo video microscopy.

PubMed

Pinter, Stephen Z; Kim, Dae-Ro; Hague, M Nicole; Chambers, Ann F; MacDonald, Ian C; Lacefield, James C

2014-08-01

Flow quantification with high-frequency (>20 MHz) power Doppler ultrasound can be performed objectively using the wall-filter selection curve (WFSC) method to select the cutoff velocity that yields a best-estimate color pixel density (CPD). An in vivo video microscopy system (IVVM) is combined with high-frequency power Doppler ultrasound to provide a method for validation of CPD measurements based on WFSCs in mouse testicular vessels. The ultrasound and IVVM systems are instrumented so that the mouse remains on the same imaging platform when switching between the two modalities. In vivo video microscopy provides gold-standard measurements of vascular diameter to validate power Doppler CPD estimates. Measurements in four image planes from three mice exhibit wide variation in the optimal cutoff velocity and indicate that a predetermined cutoff velocity setting can introduce significant errors in studies intended to quantify vascularity. Consistent with previously published flow-phantom data, in vivo WFSCs exhibited three characteristic regions and detectable plateaus. Selection of a cutoff velocity at the right end of the plateau yielded a CPD close to the gold-standard vascular volume fraction estimated using IVVM. An investigator can implement the WFSC method to help adapt cutoff velocity to current blood flow conditions and thereby improve the accuracy of power Doppler for quantitative microvascular imaging. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Doppler color imaging. Principles and instrumentation.

PubMed

Kremkau, F W

1992-01-01

DCI acquires Doppler-shifted echoes from a cross-section of tissue scanned by an ultrasound beam. These echoes are then presented in color and superimposed on the gray-scale anatomic image of non-Doppler-shifted echoes received during the scan. The flow echoes are assigned colors according to the color map chosen. Usually red, yellow, or white indicates positive Doppler shifts (approaching flow) and blue, cyan, or white indicates negative shifts (receding flow). Green is added to indicate variance (disturbed or turbulent flow). Several pulses (the number is called the ensemble length) are needed to generate a color scan line. Linear, convex, phased, and annular arrays are used to acquire the gray-scale and color-flow information. Doppler color-flow instruments are pulsed-Doppler instruments and are subject to the same limitations, such as Doppler angle dependence and aliasing, as other Doppler instruments. Color controls include gain, TGC, map selection, variance on/off, persistence, ensemble length, color/gray priority. Nyquist limit (PRF), baseline shift, wall filter, and color window angle, location, and size. Doppler color-flow instruments generally have output intensities intermediate between those of gray-scale imaging and pulsed-Doppler duplex instruments. Although there is no known risk with the use of color-flow instruments, prudent practice dictates that they be used for medical indications and with the minimum exposure time and instrument output required to obtain the needed diagnostic information.

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

NASA Astrophysics Data System (ADS)

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

1997-05-01

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

Diagnostic Accuracy of B-mode USG and Doppler Scan for Ovarian Lesions

PubMed Central

Agarwal, Vinish Kumar

2016-01-01

Introduction Ultrasonography (USG) is considered as the primary imaging modality for confirmation of ovarian mass and to differentiate them in to benign or malignant. Aim The present study was conducted with the aim to evaluate accuracy of B- mode USG and Doppler scan (Colour Doppler + Spectral Doppler) for ovarian lesions. Materials and Methods The patients included in the study were from those referred with either palpable adnexal mass or incidentally detected adnexal masses. Total 250 women were evaluated by USG, Doppler scan. Only fifty patients who had true ovarian mass intraoperatively and on histopathology were included in study, rest masses were excluded. Study parameters were morphological indexing on B- Mode USG, flow study, vessel arrangement, and vessel morphology and vessel location in Colour Doppler and resistive index and pulsatility index in spectral Doppler. Results Total 50 women were included in present study. Out of these 46% were pre-menopausal while 54% were menopaused women, 66.7% of post-menopausal women had malignant ovarian masses compared to 8.7% of premenopausal. Sensitivity, specificity, positive predictive value and negative predictive value of B-Mode USG for ovarian masses were 94.44%, 48.15%, 54.84% and 92.86% respectively, with p-value = 0.007, while sensitivity, specificity, positive predictive value and negative predictive value of Doppler scan were 85%, 90%, 85% and 90% respectively, with p-value = 0.0001. Conclusion USG and its different techniques are accepted as the primary imaging modality for early stage diagnosis of an ovarian malignancy. Statistical analysis suggests that Doppler Scan (Colour + Spectral) was more accurate (88%) than B-Mode USG (67%), but author is in view that both of these modalities should be used in conjunction to screen the ovarian lesions. PMID:27790544

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.

Strain ratio ultrasound elastography increases the accuracy of colour-Doppler ultrasound in the evaluation of Thy-3 nodules. A bi-centre university experience.

PubMed

Cantisani, Vito; Maceroni, Piero; D'Andrea, Vito; Patrizi, Gregorio; Di Segni, Mattia; De Vito, Corrado; Grazhdani, Hektor; Isidori, Andrea M; Giannetta, Elisa; Redler, Adriano; Frattaroli, Fabrizio; Giacomelli, Laura; Di Rocco, Giorgio; Catalano, Carlo; D'Ambrosio, Ferdinando

2016-05-01

To assess whether ultrasound elastography (USE) with strain ratio increases diagnostic accuracy of Doppler ultrasound in further characterisation of cytologically Thy3 thyroid nodules. In two different university diagnostic centres, 315 patients with indeterminate cytology (Thy3) in thyroid nodules aspirates were prospectively evaluated with Doppler ultrasound and strain ratio USE before surgery. Ultrasonographic features were analysed separately and together as ultrasound score, to assess sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). Receiver operating characteristic (ROC) curves to identify optimal cut-off value of the strain ratio were also provided. Diagnosis on a surgical specimen was considered the standard of reference. Higher strain ratio values were found in malignant nodules, with an optimum strain ratio cut-off of 2.09 at ROC analysis. USE with strain ratio showed 90.6% sensitivity, 93% specificity, 82.8% PPV, 96.4% NPV, while US score yielded a sensitivity of 52.9%, specificity of 84.3%, PPV 55.6% and NPV 82.9%. The diagnostic gain with strain ratio was statistically significant as proved by ROC areas, which was 0.9182 for strain ratio and 0.6864 for US score. USE with strain ratio should be considered a useful additional tool to colour-Doppler US, since it improves characterisation of thyroid nodules with indeterminate cytology. • Strain ratio measurements improve differentiation of thyroid nodules with indeterminate cytology • Elastography with strain ratio is more reliable than ultrasound features and ultrasound score • Strain ratio may help to better select patients with Thy 3 nodules candidate for surgery.

[Contrast enhanced power Doppler and color Doppler ultrasound in breast masses: Efficiency in diagnosis and contributions to differential diagnosis].

PubMed

Algül, Ali; Balci, Pinar; Seçil, Mustafa; Canda, Tülay

2003-06-01

To compare ability of detection of vascular structures by utilizing ultrasonographic contrast agent (Levovist) prior to and following power Doppler ultrasound (PDUS) and colour Doppler ultrasound (CDUS) and to determine useful parameters in the differentiation of malignant and benign breast masses by means of verified data. Vascularisation characteristics of 38 breast masses (22 malignant, 16 benign) which were confirmed by mammography and B-mode sonography were evaluated by both CDUS and PDUS following and prior to intravenous contrast application. In addition, Vmax and RI values of vascular structures were calculated by Doppler spectral evaluation. Malignant lesions showed more vascularity than benign lesions both with and without contrast enhancement. With both methods, by utilizing contrast agent, central, penetrating and tortuous vascular structures became more significant in malignant lesions when compared with benign lesions. PDUS was able to detect vascular structures better than CDUS; however, the difference was not statistically significant. Presence of peripheral vascularity was not useful in differentiating malignant from benign lesions. Vmax and RI values were higher in malignant lesions and the difference was statistically significant. In both methods, Vmax > 15 cm/sec and RI > 0.80 (CDUS), and RI > 0.70 (PDUS) were accepted as malignancy parameters. Vascular patterns of breast masses as determined with PDUS and CDUS with contrast enhancement and Doppler spectral examinations enabled differentiation of malignant and benign breast lesions. Thus, it is possible to decrease the number of unnecessary surgical interventions.

Lidar - ND Halo Scanning Doppler, Boardman - Derived Data

DOE Data Explorer

Leo, Laura

2018-01-26

The University of Notre Dame (ND) scanning LiDAR dataset used for the WFIP2 Campaign is provided. The LiDAR is a Halo Photonics Stream Line Scanning Doppler LiDAR. **It is highly recommended to discuss any planned use of these data with University of Notre Dame scientists**. For more information refer to the attached "WFIP2 Project (lidar.z07)" Readme file.

High-intensity focused ultrasound ablation assisted using color Doppler imaging for the treatment of hepatocellular carcinomas.

PubMed

Fukuda, Hiroyuki; Numata, Kazushi; Nozaki, Akito; Kondo, Masaaki; Morimoto, Manabu; Maeda, Shin; Tanaka, Katsuaki; Ohto, Masao; Ito, Ryu; Ishibashi, Yoshiharu; Oshima, Noriyoshi; Ito, Ayao; Zhu, Hui; Wang, Zhi-Biao

2013-12-01

We evaluated the usefulness of color Doppler flow imaging to compensate for the inadequate resolution of the ultrasound (US) monitoring during high-intensity focused ultrasound (HIFU) for the treatment of hepatocellular carcinoma (HCC). US-guided HIFU ablation assisted using color Doppler flow imaging was performed in 11 patients with small HCC (<3 lesions, <3 cm in diameter). The HIFU system (Chongqing Haifu Tech) was used under US guidance. Color Doppler sonographic studies were performed using an HIFU 6150S US imaging unit system and a 2.7-MHz electronic convex probe. The color Doppler images were used because of the influence of multi-reflections and the emergence of hyperecho. In 1 of the 11 patients, multi-reflections were responsible for the poor visualization of the tumor. In 10 cases, the tumor was poorly visualized because of the emergence of a hyperecho. In these cases, the ability to identify the original tumor location on the monitor by referencing the color Doppler images of the portal vein and the hepatic vein was very useful. HIFU treatments were successfully performed in all 11 patients with the assistance of color Doppler imaging. Color Doppler imaging is useful for the treatment of HCC using HIFU, compensating for the occasionally poor visualization provided by B-mode conventional US imaging.

Doppler spectra of airborne ultrasound forward scattered by the rough surface of open channel turbulent water flows.

PubMed

Dolcetti, Giulio; Krynkin, Anton

2017-11-01

Experimental data are presented on the Doppler spectra of airborne ultrasound forward scattered by the rough dynamic surface of an open channel turbulent flow. The data are numerically interpreted based on a Kirchhoff approximation for a stationary random water surface roughness. The results show a clear link between the Doppler spectra and the characteristic spatial and temporal scales of the water surface. The decay of the Doppler spectra is proportional to the velocity of the flow near the surface. At higher Doppler frequencies the measurements show a less steep decrease of the Doppler spectra with the frequency compared to the numerical simulations. A semi-empirical equation for the spectrum of the surface elevation in open channel turbulent flows over a rough bed is provided. The results of this study suggest that the dynamic surface of open channel turbulent flows can be characterized remotely based on the Doppler spectra of forward scattered airborne ultrasound. The method does not require any equipment to be submerged in the flow and works remotely with a very high signal to noise ratio.

Automated flow quantification in valvular heart disease based on backscattered Doppler power analysis: implementation on matrix-array ultrasound imaging systems.

PubMed

Buck, Thomas; Hwang, Shawn M; Plicht, Björn; Mucci, Ronald A; Hunold, Peter; Erbel, Raimund; Levine, Robert A

2008-06-01

Cardiac ultrasound imaging systems are limited in the noninvasive quantification of valvular regurgitation due to indirect measurements and inaccurate hemodynamic assumptions. We recently demonstrated that the principle of integration of backscattered acoustic Doppler power times velocity can be used for flow quantification in valvular regurgitation directly at the vena contracta of a regurgitant flow jet. We now aimed to accomplish implementation of automated Doppler power flow analysis software on a standard cardiac ultrasound system utilizing novel matrix-array transducer technology with detailed description of system requirements, components and software contributing to the system. This system based on a 3.5 MHz, matrix-array cardiac ultrasound scanner (Sonos 5500, Philips Medical Systems) was validated by means of comprehensive experimental signal generator trials, in vitro flow phantom trials and in vivo testing in 48 patients with mitral regurgitation of different severity and etiology using magnetic resonance imaging (MRI) for reference. All measurements displayed good correlation to the reference values, indicating successful implementation of automated Doppler power flow analysis on a matrix-array ultrasound imaging system. Systematic underestimation of effective regurgitant orifice areas >0.65 cm(2) and volumes >40 ml was found due to currently limited Doppler beam width that could be readily overcome by the use of new generation 2D matrix-array technology. Automated flow quantification in valvular heart disease based on backscattered Doppler power can be fully implemented on board a routinely used matrix-array ultrasound imaging systems. Such automated Doppler power flow analysis of valvular regurgitant flow directly, noninvasively, and user independent overcomes the practical limitations of current techniques.

Spatial Angular Compounding Technique for H-Scan Ultrasound Imaging.

PubMed

Khairalseed, Mawia; Xiong, Fangyuan; Kim, Jung-Whan; Mattrey, Robert F; Parker, Kevin J; Hoyt, Kenneth

2018-01-01

H-Scan is a new ultrasound imaging technique that relies on matching a model of pulse-echo formation to the mathematics of a class of Gaussian-weighted Hermite polynomials. This technique may be beneficial in the measurement of relative scatterer sizes and in cancer therapy, particularly for early response to drug treatment. Because current H-scan techniques use focused ultrasound data acquisitions, spatial resolution degrades away from the focal region and inherently affects relative scatterer size estimation. Although the resolution of ultrasound plane wave imaging can be inferior to that of traditional focused ultrasound approaches, the former exhibits a homogeneous spatial resolution throughout the image plane. The purpose of this study was to implement H-scan using plane wave imaging and investigate the impact of spatial angular compounding on H-scan image quality. Parallel convolution filters using two different Gaussian-weighted Hermite polynomials that describe ultrasound scattering events are applied to the radiofrequency data. The H-scan processing is done on each radiofrequency image plane before averaging to get the angular compounded image. The relative strength from each convolution is color-coded to represent relative scatterer size. Given results from a series of phantom materials, H-scan imaging with spatial angular compounding more accurately reflects the true scatterer size caused by reductions in the system point spread function and improved signal-to-noise ratio. Preliminary in vivo H-scan imaging of tumor-bearing animals suggests this modality may be useful for monitoring early response to chemotherapeutic treatment. Overall, H-scan imaging using ultrasound plane waves and spatial angular compounding is a promising approach for visualizing the relative size and distribution of acoustic scattering sources. Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.

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.

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

Doppler ultrasound of the central retinal artery in microgravity.

PubMed

Sirek, Adam S; Garcia, Kathleen; Foy, Millennia; Ebert, Doug; Sargsyan, Ashot; Wu, Jimmy H; Dulchavsky, Scott A

2014-01-01

Ocular changes have been noted during long-duration spaceflight; we studied central retinal artery (CRA) blood flow using Doppler before, during, and after long-term microgravity exposure in astronauts compared with data from a control group of nonastronauts subjected to head-down tilt (HDT). Available Doppler spectra of International Space Station (ISS) crewmembers were obtained from the NASA Lifetime Surveillance of Astronaut Health database, along with 2D ultrasound-derived measurements of the optic nerve sheath diameter (ONSD). CRA Doppler spectra and optic nerve sheath images were also obtained from healthy test subjects in an acute HDT experiment at 20 min of exposure (the ground-based analogue). HDT CRA peak systolic velocity in the ground-based analogue group increased by an average of 3 cm -s(-1) (33%) relative to seated values. ONSD at 300 of HDT increased by 0.5 mm relative to supine values. CRA Doppler spectra obtained on orbit were of excellent quality and demonstrated in-flight changes of +5 cm x s(-1) (50%) compared to preflight. ONSD increased in ISS crewmembers during flight relative to before flight, with some reversal postflight. A significant ONSD response to acute postural change and to spaceflight was demonstrated in this preliminary study. Increases in Doppler peak flow velocities correlated with increases in ONSD. Further investigations are warranted to corroborate the relationship between ONSD, intracranial pressure, and central retinal blood flow for occupational surveillance and research purposes.

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.

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.

Spatially Resolved MR-Compatible Doppler Ultrasound: Proof of Concept for Triggering of Diagnostic Quality Cardiovascular MRI for Function and Flow Quantification at 3T.

PubMed

Crowe, Lindsey Alexandra; Manasseh, Gibran; Chmielewski, Aneta; Hachulla, Anne-Lise; Speicher, Daniel; Greiser, Andreas; Muller, Hajo; de Perrot, Thomas; Vallee, Jean-Paul; Salomir, Rares

2018-02-01

We demonstrate the use of a magnetic-resonance (MR)-compatible ultrasound (US) imaging probe using spatially resolved Doppler for diagnostic quality cardiovascular MR imaging (MRI) as an initial step toward hybrid US/MR fetal imaging. A newly developed technology for a dedicated MR-compatible phased array ultrasound-imaging probe acquired pulsed color Doppler carotid images, which were converted in near-real time to a trigger signal for cardiac cine and flow quantification MRI. Ultrasound and MR data acquired simultaneously were interference free. Conventional electrocardiogram (ECG) and the proposed spatially resolved Doppler triggering were compared in 10 healthy volunteers. A synthetic "false-triggered" image was retrospectively processed using metric optimized gating (MOG). Images were scored by expert readers, and sharpness, cardiac function and aortic flow were quantified. Four-dimensional (4-D) flow (two volunteers) showed feasibility of Doppler triggering over a long acquisition time. Imaging modalities were compatible. US probe positioning was stable and comfortable. Image quality scores and quantified sharpness were statistically equal for Doppler- and ECG-triggering (p ). ECG-, Doppler-triggered, and MOG ejection fractions were equivalent (p ), with false-triggered values significantly lower (p < 0.0005). Aortic flow showed no difference between ECG- and Doppler-triggered and MOG (p > 0.05). 4-D flow quantification gave consistent results between ECG and Doppler triggering. We report interference-free pulsed color Doppler ultrasound during MR data acquisition. Cardiovascular MRI of diagnostic quality was successfully obtained with pulsed color Doppler triggering. The hardware platform could further enable advanced free-breathing cardiac imaging. Doppler ultrasound triggering is applicable where ECG is compromised due to pathology or interference at higher magnetic fields, and where direct ECG is impossible, i.e., fetal imaging.

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.

[Two- and three-dimensional power Doppler ultrasound in the follow-up of placenta accreta treated conservatively].

PubMed

Roulot, A; Barranger, E; Morel, O; Soyer, P; Héquet, D

2015-02-01

To determinate the potential of 2D and 3D-ultrasound in the follow-up of patients with placenta accreta treated conservatively. Seven patients with placenta accreta treated conservatively during June 2007 and September 2009 were included. The follow-up consisted in clinical examination and 2D/3D-ultrasound once a month. Criteria studied included clinical outcome, echogenicity at 2D-ultrasound, vascularisation at colour Doppler, Mean Grey at 3D-ultrasound and vascularisation, flow and perfusion index. Seven women with invasive placenta (3 placentas accreta and 2 percreta) were studied. The mean follow-up was 228 days [75-369]. Mean delay for complete elimination of residual placenta was 280 days [120-365]. The two main results were: presence of an increased anechogenicpart in residual placenta before complete resorption for all patients; a systematic and concomitant stop of genital haemorrhage and vascularisation at colour Doppler. High degrees of variability in parameters measured at 3D-ultrasound were observed between patients so that correlations with clinical outcome were found. Long and regular follow-up is essential after conservative management but the role of 3D-ultrasound compared to 2D-ultrasound was not demonstrated in this study. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

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

PubMed

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

2009-02-01

We describe early stage experiments to test the feasibility of an ultrasound brain helmet to produce multiple simultaneous real-time three-dimensional (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 (Durham, NC, USA) 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 degrees pyramidal scans. The real-time display format consists of two coronal B-mode images merged into a 128 degrees sector, two simultaneous parasagittal images merged into a 128 degrees x 64 degrees C-mode plane and a simultaneous 64 degrees axial image. Real-time 3D color Doppler scans from a skull phantom with latex blood vessel were obtained after contrast agent injection as a proof of concept. 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.

Repeatability of Doppler ultrasound measurements of hindlimb blood flow in halothane anaesthetised horses.

PubMed

Raisis, A L; Young, L E; Meire, H; Walsh, K; Taylor, P M; Lekeux, P

2000-05-01

The purpose of this study was to determine the repeatability of femoral blood flow recorded using Doppler ultrasound in anaesthetised horses. Doppler ultrasound of the femoral artery and vein was performed in 6 horses anaesthetised with halothane and positioned in left lateral recumbency. Velocity spectra, recorded using low pulse repetition frequency, were used to calculate time-averaged mean velocity (TAV), velocity of component a (TaVa), velocity of component b (TaVb), volumetric flow, early diastolic deceleration slope (EDDS) and pulsatility index (PI). Within-patient variability was determined for sequential Doppler measurements recorded during a single standardised anaesthetic episode. Within-patient variability was also determined for Doppler and cardiovascular measurements recorded during 4 separate standardised anaesthetic episodes performed at intervals of at least one month. Within-patient variation during a single anaesthetic episode was small. Coefficients of variation (cv) were <12.5% for arterial measurements and <17% for venous measurements. Intraclass correlation coefficient was >0.75 for all measurements. No significant change was observed in measurements of cardiovascular function suggesting that within-patient variation observed during a single anaesthetic episode was due to measurement error. In contrast, within-patient variation during 4 separate anaesthetic episodes was marked (cv>17%) for most Doppler measurements obtained from arteries and veins. Variation in measurements of cardiovascular function were marked (cv>20%), suggesting that there is marked biological variation in central and peripheral observed. Further studies are warranted to determine the ability of this technique to detect differences in blood flow during administration of different anaesthetic agents.

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.

Lidar - ND Halo Scanning Doppler, Boardman - Reviewed Data

DOE Data Explorer

Otarola, Sebastian

2017-10-23

The University of Notre Dame (ND) scanning LiDAR dataset used for the WFIP2 Campaign is provided. The LiDAR is a Halo Photonics Stream Line Scanning Doppler LiDAR. **It is highly recommended to discuss any planned use of these data with University of Notre Dame scientists**. For more information refer to Section 4.c) in the updated version of the "WFIP2 Project (lidar.z07)" Readme file, where the lidar.z07.b0 dataset is fully explained.

Pulmonary Capillary Hemorrhage Induced by Different Imaging Modes of Diagnostic Ultrasound.

PubMed

Miller, Douglas L; Dong, Zhihong; Dou, Chunyan; Raghavendran, Krishnan

2018-05-01

The induction of pulmonary capillary hemorrhage (PCH) is a well-established non-thermal biological effect of pulsed ultrasound in animal models. Typically, research has been done using laboratory pulsed ultrasound systems with a fixed beam and, recently, by B-mode diagnostic ultrasound. In this study, a GE Vivid 7 Dimension ultrasound machine with 10 L linear array probe was used at 6.6 MHz to explore the relative PCH efficacy of B-mode imaging, M-mode (fixed beam), color angio mode Doppler imaging and pulsed Doppler mode (fixed beam). Anesthetized rats were scanned in a warmed water bath, and thresholds were determined by scanning at different power steps, 2 dB apart, in different groups of six rats. Exposures were performed for 5 min, except for a 15-s M-mode group. Peak rarefactional pressure amplitude thresholds were 1.5 MPa for B-mode and 1.1 MPa for angio Doppler mode. For the non-scanned modes, thresholds were 1.1 MPa for M-mode and 0.6 MPa for pulsed Doppler mode with its relatively high duty cycle (7.7 × 10 -3 vs. 0.27 × 10 -3 for M-mode). Reducing the duration of M-mode to 15 s (from 300 s) did not significantly reduce PCH (area, volume or depth) for some power settings, but the threshold was increased to 1.4 MPa. Pulmonary sonographers should be aware of this unique adverse bio-effect of diagnostic ultrasound and should consider reduced on-screen mechanical index settings for potentially vulnerable patients. Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.

[Doppler study of gluteal arteries. A useful tool for excluding gluteal arterial pathology snd an important adjunct to lower limb Doppler studies].

PubMed

Bruninx, G; Salame, H; Wery, D; Delcour, C

2002-02-01

1) To determine the negative predictive value (VPN) of duplex scan in patients complaining of buttock or hip pain and thereby to distinguish vascular claudication from other musculoskeletal or neurological diseases. 2) To show its complementarity in doppler investigation of lower limb arteries. Prospective study by duplex scan and arteriography of 60 gluteal arteries in 30 consecutive patients referred to check up for lower limb arteriopathy or sexual impotence. Duplex scan was performed by posterior approach. Correlation between doppler ultrasound and arteriography was studied. The study of normal arteries was possible in all cases and only one normal gluteal artery could not be detected in a diabetic overweight patient. On 60 arteries, sensitivity of duplex was 100 percent, specificity 96 percent and VPN 100 percent. Significant obstructive lesions were always associated with pathological velocimetric waveform or were not detected. Buttock claudication can appear like a typical vascular claudication or mimic neurological or musculoskeletal diseases. It is very useful to rule out a vascular causality responsible for buttock or hip pain by simple, non-invasive and cheap exploration. A normal doppler ultrasound of gluteal arteries can rule out vascular disease responsible for buttock or hip pain thereby avoiding arteriography. The strategy of diagnostic or therapy can be modified by such additional information as shown in two case reports.

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. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

PubMed

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

2015-12-01

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

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.

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.

Survey of current practice in clinical transvaginal ultrasound scanning in the UK

PubMed Central

Shaw, Adam; Lees, Christoph

2015-01-01

During transvaginal ultrasound scanning, the fetus and other sensitive tissues are placed close to the transducer. Heating of these tissues occurs by direct conduction from the transducer and by absorption of ultrasound in the tissue. The extent of any heating will depend on the equipment and settings used, the duration of the scan, imaging modes and other aspects of scanning practice. To ensure that scans are performed with minimum risk, staff should have an appropriate knowledge of safety and follow guidelines issued by professional bodies. An online survey aiming to document current practice in transvaginal ultrasound in the UK was created and distributed to individuals performing this type of scanning. The survey posed questions about the respondents, the departments where scans were performed, the equipment used, knowledge of ultrasound safety, scanning practice and the frequency, duration and mode of transvaginal ultrasound scans for gynaecology, obstetrics and fertility applications. In all, 294 responses were obtained, mostly from sonographers (94%). From the analysis of the responses, it was clear that there was a good understanding of the general meaning of thermal and mechanical index and high awareness of guidelines issued by professional bodies. However, 40% of respondents stated that they rarely or never monitor Thermal or Mechanical indices during scanning. Scanning practice was consistent in terms of the duration of scans, scan protocols followed and use of imaging modes. The results highlight the importance of continued ultrasound safety training and promotion of safety guidelines to users. PMID:27433250

Progression of ultrasound findings of fetal syphilis after maternal treatment.

PubMed

Rac, Martha W F; Bryant, Stefanie N; McIntire, Donald D; Cantey, Joseph B; Twickler, Diane M; Wendel, George D; Sheffield, Jeanne S

2014-10-01

The purpose of this study was to evaluate ultrasound findings of fetal syphilis and to describe their progression after maternal treatment. This was a retrospective cohort study from September 1981 to June 2011 of seropositive women after 18 weeks of gestation who had an ultrasound before treatment to evaluate for fetal syphilis. Only those women who received treatment after the initial ultrasound scan, but before delivery, were included. If the initial ultrasound scan was abnormal, serial sonography was performed until resolution of the abnormality or delivery. Patient demographics, ultrasound findings, stage of syphilis, delivery, and infant outcomes were recorded. Standard statistical analyses were performed. Kaplan-Meier estimates were constructed to estimate time to resolution. Two hundred thirty-five women met the inclusion criteria; 73 of them (30%) had evidence of fetal syphilis on initial ultrasound scan. Abnormalities included hepatomegaly (79%), placentomegaly (27%), polyhydramnios (12%), ascites (10%) and abnormal middle cerebral arterial Doppler assessment (33%). After treatment, middle cerebral arterial Doppler assessment abnormalities, ascites, and polyhydramnios resolved first, followed by placentomegaly and finally hepatomegaly. Infant outcomes were available for 173 deliveries; of these, 32 infants (18%) were diagnosed with congenital syphilis. Congenital syphilis was more common when antenatal ultrasound abnormalities were present (39% vs 12%; P < .001). Infant examination findings at delivery were similar between women with and without an abnormal pretreatment ultrasound scan. However, in those infants with congenital syphilis, hepatomegaly was the most frequent abnormality found, regardless of antenatal ultrasound findings. Sonographic signs of fetal syphilis confer a higher risk of congenital syphilis at delivery for all maternal stages. Hepatomegaly develops early and resolves last after antepartum treatment. Copyright © 2014 Elsevier Inc

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.

Ultrasound-mediated microbubble enhancement of radiation therapy studied using three-dimensional high-frequency power Doppler ultrasound.

PubMed

Kwok, Sheldon J J; El Kaffas, Ahmed; Lai, Priscilla; Al Mahrouki, Azza; Lee, Justin; Iradji, Sara; Tran, William Tyler; Giles, Anoja; Czarnota, Gregory J

2013-11-01

Tumor responses to high-dose (>8 Gy) radiation therapy are tightly connected to endothelial cell death. In the study described here, we investigated whether ultrasound-activated microbubbles can locally enhance tumor response to radiation treatments of 2 and 8 Gy by mechanically perturbing the endothelial lining of tumors. We evaluated vascular changes resulting from combined microbubble and radiation treatments using high-frequency 3-D power Doppler ultrasound in a breast cancer xenograft model. We compared treatment effects and monitored vasculature damage 3 hours, 24 hours and 7 days after treatment delivery. Mice treated with 2 Gy radiation and ultrasound-activated microbubbles exhibited a decrease in vascular index to 48 ± 10% at 24 hours, whereas vascular indices of mice treated with 2 Gy radiation alone or microbubbles alone were relatively unchanged at 95 ± 14% and 78 ± 14%, respectively. These results suggest that ultrasound-activated microbubbles enhance the effects of 2 Gy radiation through a synergistic mechanism, resulting in alterations of tumor blood flow. This novel therapy may potentiate lower radiation doses to preferentially target endothelial cells, thus reducing effects on neighboring normal tissue and increasing the efficacy of cancer treatments. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

Value of Quantitative Three-dimensional Doppler Ultrasound in the Differentiation of Benign and Malignant Thyroid Nodules.

PubMed

Li, Wen-Bo; Zhang, Bo; Jiang, Yu-Xin; Zhu, Qing-Li; Zhang, Qing; Sun, Jian

2015-06-01

To investigate the role of quantitative three-dimensional (3D) power Doppler ultrasound in differentiating malignant and benign thyroid nodule. A total of 92 lesions in 86 patients were preoperatively examined using 3D power Doppler ultrasound. The Virtual Organ Computer-aided Analysis(VOCAL)-imaging program was used to analyze the stored volume ultrasound. The differences in the mean gray value (MG), vascularization index (VI), flow index(FI), and vascularization flow index (VFI) were compared between benign and malignant lesions. The MG of the malignant thyroid nodules was significantly lower than that of the benign ones (28.27±7.21 vs. 32.89±8.73,P=0.007). The benign nodules had significantly higher VI,FI,and VFI than the malignant nodules [VI:(40.43±26.55)% vs. (26.87±23.06)%,P=0.011;FI:41.03±7.19 vs. 37.51±7.17,P=0.022;VFI:18.23±14.60 vs. 11.47±12.47, P=0.009]. Also,76.5% (39/51) of the malignant nodules and 92.7% (38/41) of the benign nodules had higher VIs in the shell of the lesion than that of the whole lesion,and 80.4%(41/51) of the malignant nodules and 95.1% (39/41) of the benign nodules had higher FIs in the shell of the lesion than that of the whole lesion. Quantitative 3D power Doppler ultrasound provides a useful tool in distinguishing benign and malignant thyroid nodules. The malignant thyroid nodules have lower echoes than the benign nodules, wherese the benign nodules have larger blood flow than the malignant nodules.

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

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

PubMed Central

Hogeman, Cynthia S.; Koch, Dennis W.; Krishnan, Anandi; Momen, Afsana; Leuenberger, Urs A.

2010-01-01

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. PMID:20173048

Doppler ultrasound-guided percutaneous nephrolithotomy with two-step tract dilation for management of complex renal stones.

PubMed

Xu, Youming; Wu, Zhonghua; Yu, Jianhua; Wang, Shulong; Li, Fang; Chen, Jiushun; Liu, Jin; Chen, Kan

2012-06-01

To report our experience and assess the safety and efficacy of Doppler ultrasound-guided percutaneous nephrolithotomy (PCNL) with 2-step tract dilation for complex renal stones. From March 2009 to February 2011, 262 patients underwent PCNL. Eighty-three patients had a complete and 105 had partial staghorn calculus, and 74 had a renal pelvic stone of >2 cm in diameter. Thirty-five patients had renal surgical history. Doppler ultrasound-guided PCNL with 2-step tract dilation were performed. Stones were fragmented and cleared using a combination of ultrasonic and pneumatic lithotripters. All PCNL procedures were successful. Successful access to the collecting system was 100%. Although most of the cases (231/262) were managed satisfactorily by a single tract, a second tract was used in 31 cases. Mean operation time was 56 minutes (range 25-145). The primary stone-free rate of PCNL was 80.9%. There were 39 auxiliary procedures (13 second PCNL and 26 extracorporeal shock wave lithotripsy). One month after treatment, the overall stone-free rate was 92.7%. Five patients (1.9%) received blood transfusion. Eight patients (3.1%) with a postoperative fever of ≥38.5°C were cured by intravenous antibiotics. No other severe complications occurred. The mean postoperative stay was 3.8 days (range 2-12). Doppler ultrasound-guided PCNL with 2-step tract dilation for complex renal stones is safe, effective, and worthy of wider use in clinical practice. Copyright © 2012 Elsevier Inc. All rights reserved.

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.

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. Copyright © 2014 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

Duplex ultrasound

MedlinePlus

Vascular ultrasound; Peripheral vascular ultrasound ... A duplex ultrasound combines: Traditional ultrasound: This uses sound waves that bounce off blood vessels to create pictures. Doppler ultrasound: This ...

Integration of Real-Time Intraoperative Contrast-Enhanced Ultrasound and Color Doppler Ultrasound in the Surgical Treatment of Spinal Cord Dural Arteriovenous Fistulas.

PubMed

Della Pepa, Giuseppe Maria; Sabatino, Giovanni; Sturiale, Carmelo Lucio; Marchese, Enrico; Puca, Alfredo; Olivi, Alessandro; Albanese, Alessio

2018-04-01

In the surgical treatment of spinal dural arteriovenous fistulas (DAVFs), intraoperative definition of anatomic characteristics of the DAVF and identification of the fistulous point is mandatory to effectively exclude the DAVF. Intraoperative ultrasound and contrast-enhanced ultrasound integrated with color Doppler ultrasound was applied in the surgical setting for a cervical DAVF to identify the fistulous point and evaluate correct occlusion of the fistula. Integration of intraoperative ultrasound and contrast-enhanced ultrasound is a simple, cost-effective technique that provides an opportunity for real-time dynamic visualization of DAVF vascular patterns, identification of the fistulous point, and assessment of correct exclusion. Compared with other intraoperative tools, such as indocyanine green videoangiography, it allows the surgeon to visualize hidden anatomic and vascular structures, minimizing surgical manipulation and guiding the surgeon during resection. Copyright © 2018 Elsevier Inc. All rights reserved.

Development of a Duplex Ultrasound Simulator and Preliminary Validation of Velocity Measurements in Carotid Artery Models.

PubMed

Zierler, R Eugene; Leotta, Daniel F; Sansom, Kurt; Aliseda, Alberto; Anderson, Mark D; Sheehan, Florence H

2016-07-01

Duplex ultrasound scanning with B-mode imaging and both color Doppler and Doppler spectral waveforms is relied upon for diagnosis of vascular pathology and selection of patients for further evaluation and treatment. In most duplex ultrasound applications, classification of disease severity is based primarily on alterations in blood flow velocities, particularly the peak systolic velocity (PSV) obtained from Doppler spectral waveforms. We developed a duplex ultrasound simulator for training and assessment of scanning skills. Duplex ultrasound cases were prepared from 2-dimensional (2D) images of normal and stenotic carotid arteries by reconstructing the common carotid, internal carotid, and external carotid arteries in 3 dimensions and computationally simulating blood flow velocity fields within the lumen. The simulator displays a 2D B-mode image corresponding to transducer position on a mannequin, overlaid by color coding of velocity data. A spectral waveform is generated according to examiner-defined settings (depth and size of the Doppler sample volume, beam steering, Doppler beam angle, and pulse repetition frequency or scale). The accuracy of the simulator was assessed by comparing the PSV measured from the spectral waveforms with the true PSV which was derived from the computational flow model based on the size and location of the sample volume within the artery. Three expert examiners made a total of 36 carotid artery PSV measurements based on the simulated cases. The PSV measured by the examiners deviated from true PSV by 8% ± 5% (N = 36). The deviation in PSV did not differ significantly between artery segments, normal and stenotic arteries, or examiners. To our knowledge, this is the first simulation of duplex ultrasound that can create and display real-time color Doppler images and Doppler spectral waveforms. The results demonstrate that an examiner can measure PSV from the spectral waveforms using the settings on the simulator with a mean absolute error

The usefulness of Duplex Doppler ultrasound in the angiological and dermatological diagnosis of patients with blue toe syndrome.

PubMed

Pawlaczyk, Katarzyna; Gabriel, Marcin; Strzelecka-Węklar, Daria A; Krasiński, Zbigniew; Stanisic, Michal; Gabriel, Zofia; Dzieciuchowicz, Łukasz; Adamski, Zygmunt

2017-10-01

Peripheral microembolism is one of the most frequent causes of acute limb ischemia. In order to effectively prevent relapses it is essential to localize and eliminate the source of embolism. To evaluate the role of Duplex Doppler ultrasound examination in identifying the causes of blue toe syndrome (BTS). The group of 165 patients with clinical symptoms of BTS on their upper limbs ( n = 16) and lower limbs ( n = 149) was investigated. They all underwent Duplex Doppler ultrasound of the major arteries of the extremities, where ischemic changes occurred. Morphological and functional changes which might be potential sources of microembolism were identified in 146 patients. These changes included significant short-length stenoses or unstable atherosclerotic plaque ( n = 73), true aneurysms ( n = 42) and pseudoaneurysms ( n = 17). In 11 cases, pathology of vascular prostheses in the form of anastomotic aneurysms, infection and residual thrombi after fibrinolysis was detected. In all cases, Duplex diagnosis was confirmed by other imaging and intraoperative tests. Duplex Doppler ultrasound of the arteries in the affected limb with a full length view should be the first-line examination in diagnosing patients with BTS. In the absence of hemodynamic blood flow disturbances in the major arteries in patients with symptoms of BTS, it is advisable to start haematological tests to identify/exclude congenital or acquired thrombophilia.

Doppler ultrasonography of the anterior knee tendons in elite badminton players: colour fraction before and after match.

PubMed

Koenig, M J; Torp-Pedersen, S; Boesen, M I; Holm, C C; Bliddal, H

2010-02-01

Anterior knee tendon problems are seldom reported in badminton players although the game is obviously stressful to the lower extremities. Painful anterior knee tendons are common among elite badminton players. The anterior knee tendons exhibit colour Doppler activity. This activity increases after a match. Painful tendons have more Doppler activity than tendons without pain. Cohort study. 72 elite badminton players were interviewed about training, pain and injuries. The participants were scanned with high-end ultrasound equipment. Colour Doppler was used to examine the tendons of 64 players before a match and 46 players after a match. Intratendinous colour Doppler flow was measured as colour fraction (CF). The tendon complex was divided into three loci: the quadriceps tendon, the proximal patellar tendon and the insertion on the tibial tuberosity. Interview: Of the 72 players, 62 players had problems with 86 tendons in the lower extremity. Of these 86 tendons, 48 were the anterior knee tendons. Ultrasound: At baseline, the majority of players (87%) had colour Doppler flow in at least one scanning position. After a match, the percentage of the knee complexes involved did not change. CF increased significantly in the dominant leg at the tibial tuberosity; single players had a significantly higher CF after a match at the tibial tuberosity and in the patellar tendon both before and after a match. Painful tendons had the highest colour Doppler activity. Most elite badminton players had pain in the anterior knee tendons and intratendinous Doppler activity both before and after match. High levels of Doppler activity were associated with self-reported ongoing pain.

Reliability of laser Doppler, near-infrared spectroscopy and Doppler ultrasound for peripheral blood flow measurements during and after exercise in the heat.

PubMed

Choo, Hui C; Nosaka, Kazunori; Peiffer, Jeremiah J; Ihsan, Mohammed; Yeo, Chow C; Abbiss, Chris R

2017-09-01

This study examined the test-retest reliability of near-infrared spectroscopy (NIRS), laser Doppler flowmetry (LDF) and Doppler ultrasound to assess exercise-induced haemodynamics. Nine men completed two identical trials consisting of 25-min submaximal cycling at first ventilatory threshold followed by repeated 30-s bouts of high-intensity (90% of peak power) cycling in 32.8 ± 0.4°C and 32 ± 5% relative humidity (RH). NIRS (tissue oxygenation index [TOI] and total haemoglobin [tHb]) and LDF (perfusion units [PU]) signals were monitored continuously during exercise, and leg blood flow was assessed by Doppler ultrasound at baseline and after exercise. Cutaneous vascular conductance (CVC; PU/mean arterial pressure (MAP)) was expressed as the percentage change from baseline (%CVC BL ). Coefficients of variation (CVs) as indicators of absolute reliability were 18.7-28.4%, 20.2-33.1%, 42.5-59.8%, 7.8-12.4% and 22.2-30.3% for PU, CVC, %CVC BL , TOI and tHb, respectively. CVs for these variables improved as exercise continued beyond 10 min. CVs for baseline and post-exercise leg blood flow were 17.8% and 10.5%, respectively. CVs for PU, tHb (r 2  = 0.062) and TOI (r 2  = 0.002) were not correlated (P > 0.05). Most variables demonstrated CVs lower than the expected changes (35%) induced by training or heat stress; however, minimum of 10 min exercise is recommended for more reliable measurements.

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…

A New Ka-Band Scanning Radar Facility: Polarimetric and Doppler Spectra Measurements of Snow Events

NASA Astrophysics Data System (ADS)

Oue, M.; Kollias, P.; Luke, E. P.; Mead, J.

2017-12-01

Polarimetric radar analyses offer the capability of identification of ice hydrometeor species as well as their spatial distributions. In addition to polarimetric parameter observations, Doppler spectra measurements offer unique insights into ice particle properties according to particle fall velocities. In particular, millimeter-wavelength radar Doppler spectra can reveal supercooled liquid cloud droplets embedded in ice precipitation clouds. A Ka-band scanning polarimetric radar, named KASPR, was installed in an observation facility at Stony Brook University, located 22 km west of the KOKX NEXRAD radar at Upton, NY. The KASPR can measure Doppler spectra and full polarimetric variables, including radar reflectivity, differential reflectivity (ZDR), differential phase (φDP), specific differential phase (KDP), correlation coefficient (ρhv), and linear depolarization ratio (LDR). The facility also includes a micro-rain radar and a microwave radiometer capable of measuring reflectivity profiles and integrated liquid water path, respectively. The instruments collected initial datasets during two snowstorm events and two snow shower events in March 2017. The radar scan strategy was a combination of PPI scans at 4 elevation angles (10, 20, 45, and 60°) and RHI scans in polarimetry mode, and zenith pointing with Doppler spectra collection. During the snowstorm events the radar observed relatively larger ZDR (1-1.5 dB) and enhanced KDP (1-2 ° km-1) at heights corresponding to a plate/dendrite crystal growth regime. The Doppler spectra showed that slower-falling particles (< 0.5 m s-1) coexisted with faster-falling particles (> 1 m s-1). The weakly increased ZDR could be produced by large, faster falling particles such as quasi-spherical aggregates, while the enhanced KDP could be produced by highly-oriented oblate, slowly-falling particles. Below 2 km altitude, measurements of dual wavelength ratio (DWR) based on Ka and S-band reflectivities from the KASPR and NEXRAD

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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/broadbandmore » 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.« less

Anthropomorphic cardiac ultrasound phantom.

PubMed

Smith, S W; Rinaldi, J E

1989-10-01

A new phantom is described which simulates the human cardiac anatomy for applications in ultrasound imaging, ultrasound Doppler, and color-flow Doppler imaging. The phantom consists of a polymer left ventricle which includes a prosthetic mitral and aortic valve and is connected to a mock circulatory loop. Aerated tap water serves as a blood simulating fluid and ultrasound contrast medium within the circulatory loop. The left ventricle is housed in a Lexan ultrasound visualization chamber which includes ultrasound viewing ports and acoustic absorbers. A piston pump connected to the visualization chamber by a single port pumps degassed water within the chamber which in turn pumps the left ventricle. Real-time ultrasound images and Doppler studies measure flow patterns through the valves and within the left ventricle.

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

PubMed

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

2018-04-01

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

Is articular pain in rheumatoid arthritis correlated with ultrasound power Doppler findings?

PubMed

Pereira, Daniele Freitas; Gutierrez, Marwin; de Buosi, Ana Leticia Pirozzi; Ferreira, Fernando Bernardes Maia Diniz; Draghessi, Antonella; Grassi, Walter; Natour, Jamil; Furtado, Rita Nely Vilar

2015-11-01

The study is addressed to determine if there is a correlation between intra-articular power Doppler (PD) and pain symptoms in patients with rheumatoid arthritis (RA). A cross-sectional study of patients with established RA was rolled out. Seventy-two patients with chronic swelling at metacarpophalangeal (MCP) joints were consecutively enrolled in the study and divided into two groups (painful and painless). In the painful group, the inclusion criteria were pain in the visual analog scale (VAS), from 0 to 10 cm, of at least 4 cm and 0 in the painless group. All two to five MCP joints, bilaterally, were scanned by ultrasound (US) searching for intra-articular PD presence. Any value of p < 0.05 was considered significant. Patients in the painful group had longer morning stiffness, worse 28-joint disease activity score (DAS 28), and health assessment questionnaire (HAQ) indexes. There were no association between pain and gray scale (GS) synovitis, odds ratio (OR) = 0.9 (0.6-1.2), p = 0.485; and pain and intra-articular PD, OR = 0.8 (0.6-1.2), p = 0.244. Intra-articular PD was not correlated with pain symptom in this study.

Why do women seek ultrasound scans from commercial providers during pregnancy?

PubMed

Roberts, Julie; Griffiths, Frances E; Verran, Alice; Ayre, Catherine

2015-05-01

The commercial availability of ultrasound scans for pregnant women has been controversial yet little is known about why women make use of such services. This article reports on semi-structured interviews with women in the UK who have booked a commercial scan, focusing on the reasons women gave for booking commercially provided ultrasound during a low-risk pregnancy. Participants' reasons for booking a scan are presented in five categories: finding out the sex of the foetus; reassurance; seeing the baby; acquiring keepsakes and facilitating bonding. Our analysis demonstrates that women's reasons for booking commercial scans are often multiple and are shaped by experiences of antenatal care as well as powerful cultural discourses related to 'good' parenting and the use of technology in pregnancy. Sociological and public debate about the availability of commercial ultrasound and its social and personal impacts should consider the wider sociocultural context that structures women's choices to make use of such services. © 2015 Foundation for the Sociology of Health & Illness.

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.

Dense concentric circle scanning protocol for measuring pulsatile retinal blood flow in rats with Doppler optical coherence tomography

NASA Astrophysics Data System (ADS)

Tan, Bingyao; Hosseinaee, Zohreh; Bizheva, Kostadinka

2017-11-01

The variability in the spatial orientation of retinal blood vessels near the optic nerve head (ONH) results in imprecision of the measured Doppler angle and therefore the pulsatile blood flow (BF), when those parameters are evaluated using Doppler OCT imaging protocols based on dual-concentric circular scans. Here, we utilized a dense concentric circle scanning protocol and evaluated its precision for measuring pulsatile retinal BF in rats for different numbers of the circular scans. An spectral domain optical coherence tomography (SD-OCT) system operating in the 1060-nm spectral range with image acquisition rate of 47,000 A-scans/s was used to acquire concentric circular scans centered at the rat's ONH, with diameters ranging from 0.8 to 1.0 mm. A custom, automatic blood vessel segmentation algorithm was used to track the spatial orientation of the retinal blood vessels in three dimensions, evaluate the spatially dependent Doppler angle and calculate more accurately the axial BF for each major retinal blood vessel. Metrics such as retinal BF, pulsatility index, and resistance index were evaluated for each and all of the major retinal blood vessels. The performance of the proposed dense concentric circle scanning protocols was compared with that of the dual-circle scanning protocol. Results showed a 3.8±2.2 deg difference in the Doppler angle calculation between the two approaches, which resulted in ˜7% difference in the calculated retinal BF.

Detection of vascularity in wrist tenosynovitis: power doppler ultrasound compared with contrast-enhanced grey-scale ultrasound.

PubMed

Klauser, Andrea S; Franz, Magdalena; Arora, Rohit; Feuchtner, Gudrun M; Gruber, Johann; Schirmer, Michael; Jaschke, Werner R; Gabl, Markus F

2010-01-01

We sought to assess vascularity in wrist tenosynovitis by using power Doppler ultrasound (PDUS) and to compare detection of intra- and peritendinous vascularity with that of contrast-enhanced grey-scale ultrasound (CEUS). Twenty-six tendons of 24 patients (nine men, 15 women; mean age ± SD, 54.4 ± 11.8 years) with a clinical diagnosis of tenosynovitis were examined with B-mode ultrasonography, PDUS, and CEUS by using a second-generation contrast agent, SonoVue (Bracco Diagnostics, Milan, Italy) and a low-mechanical-index ultrasound technique. Thickness of synovitis, extent of vascularized pannus, intensity of peritendinous vascularisation, and detection of intratendinous vessels was incorporated in a 3-score grading system (grade 0 to 2). Interobserver variability was calculated. With CEUS, a significantly greater extent of vascularity could be detected than by using PDUS (P < 0.001). In terms of peri- and intratendinous vessels, CEUS was significantly more sensitive in the detection of vascularization compared with PDUS (P < 0.001). No significant correlation between synovial thickening and extent of vascularity could be found (P = 0.089 to 0.097). Interobserver reliability was calculated to be excellent when evaluating the grading score (κ = 0.811 to 1.00). CEUS is a promising tool to detect tendon vascularity with higher sensitivity than PDUS by improved detection of intra- and peritendinous vascularity.

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.

[Urodynamics foundations: contractile potency and urethral doppler].

PubMed

Benítez Navío, Julio; Caballero Gómez, Pilar; Delgado Elipe, Ildefonso

2002-12-01

To calculate the bladder softening factor, elastic constant and contractile potency. For the analysis we considered bladder behavior like that of a spring. See articles 1 and 2 published in this issue. Using flowmetry, Doppler ultrasound and abdominal pressure (Transrectal pressure register catheter) an analytical solution that permits calculation of factors defining bladder behavior was looked for. Doppler ultrasound allows us to know urine velocity through the prostatic urethra and, therefore, to calculate bladder contractile potency. Equations are solved reaching an analytical solution that allows calculating those factors that define bladder behavior: Bladder contractile potency, detrusor elastic constant, considering it behaves like a spring, and calculation of muscle resistance to movement. All thanks to Doppler ultrasound that allows to know urine speed. The bladder voiding phase is defined with the aforementioned factors; storage phase behavior can be indirectly inferred. Only uroflowmetry curves, Doppler ultrasound and abdominal pressure value are used. We comply with the so called non invasive urodynamics although for us it is just another phase in the biomechanical study of the detrusor muscle. Main conclusion is the addition of Doppler ultrasound to the urodynamist armamentarium as an essential instrument for the comprehension of bladder dynamics and calculation of bladder behavior defining factors. It is not a change in the focus but in the methods, gaining knowledge and diminishing invasion.

Fast scanning probe for ophthalmic echography using an ultrasound motor.

PubMed

Carotenuto, Riccardo; Caliano, Giosuè; Caronti, Alessandro; Savoia, Alessandro; Pappalardo, Massimo

2005-11-01

High-frequency transducers, up to 35-50 MHz, are widely used in ophthalmic echography to image fine eye structures. Phased-array techniques are not practically applicable at such a high frequency, due to the too small size required for the single transducer element, and mechanical scanning is the only practical alternative. At present, all ophthalmic ultrasound systems use focused single-element, mechanically scanned probes. A good probe positioning and image evaluation feedback requires an image refresh-rate of about 15-30 frames per second, which is achieved in commercial mechanical scanning probes by using electromagnetic motors. In this work, we report the design, construction, and experimental characterization of the first mechanical scanning probe for ophthalmic echography based on a small piezoelectric ultrasound motor. The prototype probe reaches a scanning rate of 15 sectors per second, with very silent operation and little weight. The first high-frequency echographic images obtained with the prototype probe are presented.

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.

Influence of Scan Duration on Pulmonary Capillary Hemorrhage Induced by Diagnostic Ultrasound.

PubMed

Miller, Douglas L; Dong, Zhihong; Dou, Chunyan; Raghavendran, Krishnan

2016-08-01

Diagnostic ultrasound can induce pulmonary capillary hemorrhage (PCH) in rats and display this as "comet tail" artifacts (CTAs) after a time delay. To test the hypothesis that no PCH occurs for brief scans, anesthetized rats were scanned using a 6-MHz linear array for different durations. PCH was characterized by ultrasound CTAs, micro-computed tomography (μCT), and measurements of fixed lung tissue. The μCT images revealed regions of PCH, sometimes penetrating the entire depth of a lobe, which were reflected in the fixed tissue measurements. At -3 dB of power, PCH was substantial for 300-s scans, but not significant for 25-s scans. At 0 dB, PCH was not strongly dependent on scan durations of 300 to 10 s. Contrary to the hypothesis, CTAs were not evident during most 10-s scans (p > 0.05), but PCH was significant (p = 0.02), indicating that PCH could occur without evidence of the injury in the images. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Doppler ultrasound of the placenta and maternal and fetal vessels during normal gestation in captive agoutis (Dasyprocta prymnolopha, Wagler, 1831).

PubMed

Sousa, Francisco C A; Pessoa, Gerson T; Moura, Laecio S; Rodrigues, Renan P S; Diniz, Anaemilia N; Souza, André B; Silva, Elzivânia G; Sanches, Marina P; Silva-Filho, Osmar F; Guerra, Porfirio C; Sousa, João M; Neves, Willams C; Alves, Flávio R

2016-11-01

The use of ultrasound for pregnancy monitoring is critical for the evaluation of hemodynamic parameters essential to fetal viability. In the present study, using B-mode and Doppler ultrasound, we characterized the placenta, subplacenta, maternal, and fetal vessels during normal gestation of healthy agoutis raised in captivity. In total, 30 agoutis were obtained from the Center for the Study and Preservation of Wild Animals, Center of Agricultural Sciences, Federal University of Piauí (Núcleo de Estudos e Preservação de Animais Silvestres-NEPAS, Centro de Ciências Agrárias-CCA, Universidade Federal do Piauí-UFPI). These animals were subjected to B-mode and Doppler ultrasound examinations to evaluate their maternal and fetal hemodynamic profiles. The placenta was located in the mesometrial region and had a discoid, ellipsoid, or globular aspect. With spectral Doppler, characteristic systolic and diastolic flow was observed in the umbilical artery. This flow increased during pregnancy. A cross-sectional view revealed a goblet-shaped placenta. The uteroplacental blood flow was characterized by a marked increase in systolic peak velocity during pregnancy, the presence of a rapid deceleration ramp, and a relatively high diastolic speed. The fetal aortic vascular flow was predominantly systolic and diastolic. The caudal vena cava blood flow was characterized by a systolic peak followed by a decreased diastolic wave throughout pregnancy. In the present study, we characterized the morphologic and hemodynamic interactions of the placenta/subplacenta with maternal and fetal vessels in agoutis at 30, 45, 60, 75, and 90 days gestation using B-mode and Doppler ultrasound. We determined the approximation and separation of the blood flow values of the umbilical artery, subplacental flow, uteroplacental artery, fetal aorta, and fetal vena cava. We believe these values may contribute to an understanding of the gestational biology and aid delivery prediction in this species

Velocity measurement by vibro-acoustic Doppler.

PubMed

Nabavizadeh, Alireza; Urban, Matthew W; Kinnick, Randall R; Fatemi, Mostafa

2012-04-01

We describe the theoretical principles of a new Doppler method, which uses the acoustic response of a moving object to a highly localized dynamic radiation force of the ultrasound field to calculate the velocity of the moving object according to Doppler frequency shift. This method, named vibro-acoustic Doppler (VAD), employs two ultrasound beams separated by a slight frequency difference, Δf, transmitting in an X-focal configuration. Both ultrasound beams experience a frequency shift because of the moving objects and their interaction at the joint focal zone produces an acoustic frequency shift occurring around the low-frequency (Δf) acoustic emission signal. The acoustic emission field resulting from the vibration of the moving object is detected and used to calculate its velocity. We report the formula that describes the relation between Doppler frequency shift of the emitted acoustic field and the velocity of the moving object. To verify the theory, we used a string phantom. We also tested our method by measuring fluid velocity in a tube. The results show that the error calculated for both string and fluid velocities is less than 9.1%. Our theory shows that in the worst case, the error is 0.54% for a 25° angle variation for the VAD method compared with an error of -82.6% for a 25° angle variation for a conventional continuous wave Doppler method. An advantage of this method is that, unlike conventional Doppler, it is not sensitive to angles between the ultrasound beams and direction of motion.

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.

Usefulness of the twinkling artifact on Doppler ultrasound for the detection of breast microcalcifications.

PubMed

Relea, A; Alonso, J A; González, M; Zornoza, C; Bahamonde, S; Viñuela, B E; Encinas, M B

2018-06-12

To determine whether the twinkling artifact on Doppler ultrasound imaging corresponds to microcalcifications previously seen on mammograms and to evaluate the usefulness of this finding in the ultrasound management of suspicious microcalcifications. We used ultrasonography to prospectively examine 46 consecutive patients with groups of microcalcifications suspicious for malignancy identified at mammography, searching for the presence of the twinkling artifact to identify the microcalcifications. Once we identified the microcalcifications, we obtained core-needle biopsy specimens with 11G needles and then used X-rays to check the specimens for the presence of microcalcifications. We analyzed the percentage of detection and obtainment of microcalcifications by core-needle biopsy with this technique and the radiopathologic correlation. Microcalcifications that were not detected by ultrasound or discordant lesions were biopsied by stereotaxy at another center. We also used ultrasound guidance for preoperative marking with clips, usually orienting them radially. We identified and biopsied 41 of the 46 lesions under ultrasound guidance, including 24 of 25 carcinomas (17 in situ). B-mode ultrasound was sufficient for biopsying the microcalcifications in 14 patients, although the presence of the twinkling artifact increased the number of microcalcifications detected and thus enabled more accurate preoperative marking. Thanks to the twinkling sign, we were able to identify 27 additional groups of microcalcifications (89% vs. 30%; p < 0.05). All the surgical specimens had margins free of disease. The twinkling artifact is useful for microcalcifications in ultrasound examinations, enabling a significant increase in the yield of ultrasound-guided biopsies and better preoperative marking of groups of microcalcifications. Copyright © 2018 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

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

Colour Doppler ultrasound in preoperative assessment of the neck vessels in patients with tumours of the oral cavity and the neck region.

PubMed

Falkowski, Aleksander; Wilk, Grazyna; Mokrzyński, Stanisław; Dul, Przemysław; Toloczko-Grabarek, Aleksandra; Huzarski, Tomasz; Kowalczyk, Robert

2004-06-01

The aim of the study was not only to establish the applicability of color Doppler ultrasound of the neck vessels in patients with tumors of the oral cavity and the neck region but also to check whether the coexistence of sclerotic changes in the carotid arteries is essential in determination of the sequence of surgical procedure. Color Doppler ultrasound was performed on 110 patients, aged 15 -71 years with tumors of the oral cavity and the neck. The localization, size, echogenicity, as well as the tumor relationship to the surrounding structures and big vessels of the neck region was analyzed. Compression of the veins was observed in 27 cases, and of the arteries only in 20 cases. Infiltration of the jugular vein was observed in 8 patients, whereas infiltration of the carotid artery were seen only in 6 patients. Severe internal carotid artery stenosis, due to arteriosclerosis, was observed in 10 patients. Three persons were suggested to be operated on, first due to carotid artery stenosis, later on, due to the oral cavity tumor. It was found that color Doppler ultrasound is useful in deciding upon the method of treatment, while the examination of the neck vessels is helpful in establishing the sequence of surgical procedures in patients with tumors and coexisting arteriosclerosis.

Nanoscale Imaging of Buried Structures via Scanning Near-Field Ultrasound Holography

NASA Astrophysics Data System (ADS)

Shekhawat, Gajendra S.; Dravid, Vinayak P.

2005-10-01

A nondestructive imaging method, scanning near-field ultrasound holography (SNFUH), has been developed that provides depth information as well as spatial resolution at the 10- to 100-nanometer scale. In SNFUH, the phase and amplitude of the scattered specimen ultrasound wave, reflected in perturbation to the surface acoustic standing wave, are mapped with a scanning probe microscopy platform to provide nanoscale-resolution images of the internal substructure of diverse materials. We have used SNFUH to image buried nanostructures, to perform subsurface metrology in microelectronic structures, and to image malaria parasites in red blood cells.

Twinkling artifact on color Doppler ultrasound: an advantage or a pitfall?

PubMed

Ozan, Ebru; Atac, Gokce Kaan; Gundogdu, Sadi

2016-07-01

The twinkling artifact (TA) or color comet-tail artifact is characterized by a rapidly changing mixture of red and blue color Doppler signals. Even though many diseases and clinical conditions have been shown to produce this artifact, its source is not clearly understood yet. The TA may provide additional information to gray-scale ultrasound findings in several clinical situations. However, there may be pitfalls to keep in mind. We must first be aware of the TA to benefit from the advantages and avoid the pitfalls. In this review, we aim to give practicing radiologists an overview of the mechanisms and clinical applications of the TA by illustrating sample cases we have encountered.

Time-resolved flowmetering of gas-liquid two-phase pipe flow by ultrasound pulse Doppler method

NASA Astrophysics Data System (ADS)

Murai, Yuichi; Tasaka, Yuji; Takeda, Yasushi

2012-03-01

Ultrasound pulse Doppler method is applied for componential volumetric flow rate measurement in multiphase pipe flow consisted of gas and liquid phases. The flowmetering is realized with integration of measured velocity profile over the cross section of the pipe within liquid phase. Spatio-temporal position of interface is detected also with the same ultrasound pulse, which further gives cross sectional void fraction. A series of experimental demonstration was shown by applying this principle of measurement to air-water two-phase flow in a horizontal tube of 40 mm in diameter, of which void fraction ranges from 0 to 90% at superficial velocity from 0 to 15 m/s. The measurement accuracy is verified with a volumetric type flowmeter. We also analyze the accuracy of area integration of liquid velocity distribution for many different patterns of ultrasound measurement lines assigned on the cross section of the tube. The present method is also identified to be pulsation sensor of flow rate that fluctuates with complex gas-liquid interface behavior.

[Current role of color Doppler ultrasound in acute renal failure].

PubMed

Bertolotto, M; Quaia, E; Rimondini, A; Lubin, E; Pozzi Mucelli, R

2001-01-01

Acute Renal Failure (ARF) is characterized by a rapid decline of the glomerular filtration rate, due to hypotension (prerenal ARF), obstruction of the urinary tract (post-renal ARF) or renal parenchymal disease (renal ARF). The differential diagnosis among different causes of ARF is based on anamnesis, clinical symptoms and laboratory data. Usually ultrasound (US) is the only imaging examination performed in these patients, because it is safe and readily available. In patients with ARF gray scale US is usually performed to rule out obstruction since it is highly sensitive to recognize hydronephrosis. Patients with renal ARF have no specific changes in renal morphology. The size of the kidneys is usually normal or increased, with smooth margins. Detection of small kidneys suggests underlying chronic renal pathology and worse prognosis. Echogenicity and parenchymal thickness are usually normal, but in some cases there are hyperechogenic kidneys, increased parenchymal thickness and increased cortico-medullary differentiation. Evaluation of renal vasculature with pulsed Doppler US is useful in the differential diagnosis between prerenal ARF and acute tubular necrosis (ATN), and in the diagnosis of renal obstruction. Latest generation US apparatus allow color Doppler and power Doppler evaluation of renal vasculature up to the interlobular vessels. A significant, but non specific, reduction in renal perfusion is usually appreciable in the patients with ARF. There are renal pathologic conditions presenting with ARF in which color Doppler US provides more specific morphologic and functional information. In particular, color Doppler US often provides direct or indirect signs which can lead to the right diagnosis in old patients with chronic renal insufficiency complicated with ARF, in patients with acute pyelonephritis, hepatic disease, vasculitis, thrombotic microangiopathies, and in patients with acute thrombosis of the renal artery and vein. Contrast enhanced US is

Feasibility study: real-time 3-D ultrasound imaging of the brain.

PubMed

Smith, Stephen W; Chu, Kengyeh; Idriss, Salim F; Ivancevich, Nikolas M; Light, Edward D; Wolf, Patrick D

2004-10-01

We tested the feasibility of real-time, 3-D ultrasound (US) imaging in the brain. The 3-D scanner uses a matrix phased-array transducer of 512 transmit channels and 256 receive channels operating at 2.5 MHz with a 15-mm diameter footprint. The real-time system scans a 65 degrees pyramid, producing up to 30 volumetric scans per second, and features up to five image planes as well as 3-D rendering, 3-D pulsed-wave and color Doppler. In a human subject, the real-time 3-D scans produced simultaneous transcranial horizontal (axial), coronal and sagittal image planes and real-time volume-rendered images of the gross anatomy of the brain. In a transcranial sheep model, we obtained real-time 3-D color flow Doppler scans and perfusion images using bolus injection of contrast agents into the internal carotid artery.

Videodermoscopy and doppler-ultrasound in spider naevi: towards a new classification?

PubMed

Alegre-Sánchez, A; Bernárdez, C; Fonda-Pascual, P; Moreno-Arrones, O M; López-Gutiérrez, J C; Jaén-Olasolo, P; Boixeda, P

2018-01-01

Spider naevi (SN) are considered a subtype of telangiectasias, currently classified as low-flow vascular malformations. To describe the videodermoscopy and Doppler-ultrasound (US) features of a large group of SN. A retrospective study of cases of SN collected at our Dermatology department during the period between June 2015 and June 2017 was performed. Clinical images, dermoscopic, videodermoscopic and Doppler-US files were reviewed. For each case, the age of the patient, time since onset, size and dermoscopic pattern of the lesions were recorded. The presence of pulsatility was also evaluated visually on the videodermoscopy. Two hundred and thirty-three SN in 189 patients were included. The mean age was 39.5 years (range: 10-76 years). Mean size of the lesions was 4.1 ± 2.0 mm. We described three dermoscopic patterns: network, star and looping. Older age, longer time since onset and larger size were found associated with higher frequency of the looping and star patterns compared to that of network pattern (P < 0.01). Pulsatility during videodermoscopy was found in 88 patients (37%). This pulsatility phenomenon was more commonly associated with the looping pattern (64.7%) than star- (40.3%) or network-like patterns (29.9%) (P < 0.001). In Doppler-US studies, a high-flow with arterial biphasic waveform was found. In the light of the results, we support that SN could be reconsidered in upcoming classifications as lesions closer to the group of high-flow arteriovenous malformations. © 2017 European Academy of Dermatology and Venereology.

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

Using Flow Characteristics in Three-Dimensional Power Doppler Ultrasound Imaging to Predict Complete Responses in Patients Undergoing Neoadjuvant Chemotherapy.

PubMed

Shia, Wei-Chung; Huang, Yu-Len; Wu, Hwa-Koon; Chen, Dar-Ren

2017-05-01

Strategies are needed for the identification of a poor response to treatment and determination of appropriate chemotherapy strategies for patients in the early stages of neoadjuvant chemotherapy for breast cancer. We hypothesize that power Doppler ultrasound imaging can provide useful information on predicting response to neoadjuvant chemotherapy. The solid directional flow of vessels in breast tumors was used as a marker of pathologic complete responses (pCR) in patients undergoing neoadjuvant chemotherapy. Thirty-one breast cancer patients who received neoadjuvant chemotherapy and had tumors of 2 to 5 cm were recruited. Three-dimensional power Doppler ultrasound with high-definition flow imaging technology was used to acquire the indices of tumor blood flow/volume, and the chemotherapy response prediction was established, followed by support vector machine classification. The accuracy of pCR prediction before the first chemotherapy treatment was 83.87% (area under the ROC curve [AUC] = 0.6957). After the second chemotherapy treatment, the accuracy of was 87.9% (AUC = 0.756). Trend analysis showed that good and poor responders exhibited different trends in vascular flow during chemotherapy. This preliminary study demonstrates the feasibility of using the vascular flow in breast tumors to predict chemotherapeutic efficacy. © 2017 by the American Institute of Ultrasound in Medicine.

Is there subclinical enthesitis in early psoriatic arthritis? A clinical comparison with power doppler ultrasound.

PubMed

Freeston, J E; Coates, L C; Helliwell, P S; Hensor, E M A; Wakefield, R J; Emery, P; Conaghan, P G

2012-10-01

Enthesitis is a recognized feature of spondylarthritides (SpA), including psoriatic arthritis (PsA). Previously, ultrasound imaging has highlighted the presence of subclinical enthesitis in established SpA, but there are little data on ultrasound findings in early PsA. The aim of our study was to compare ultrasound and clinical examination (CE) for the detection of entheseal abnormalities in an early PsA cohort. Forty-two patients with new-onset PsA and 10 control subjects underwent CE of entheses for tenderness and swelling, as well as gray-scale (GS) and power Doppler (PD) ultrasound of a standard set of entheses. Bilateral elbow lateral epicondyles, Achilles tendons, and plantar fascia were assessed by both CE and ultrasound, the latter scored using a semiquantitative (SQ) scale. Inferior patellar tendons were assessed by ultrasound alone. A GS SQ score of >1 and/or a PD score of >0 was used to describe significant ultrasound entheseal abnormality. A total of 24 (57.1%) of 42 patients in the PsA group and 0 (0%) of 10 controls had clinical evidence of at least 1 tender enthesis. In the PsA group, for sites assessed by both CE and ultrasound, 4% (7 of 177) of nontender entheses had a GS score >1 and/or a PD score >0 compared to 24% (9 of 37) of tender entheses. CE overestimated activity in 28 (13%) of 214 of entheses. All the nontender ultrasound-abnormal entheses were in the lower extremity. The prevalence of subclinical enthesitis in this early PsA cohort was low. CE may overestimate active enthesitis. The few subclinically inflamed entheses were in the lower extremity, where mechanical stress is likely to be more significant. Copyright © 2012 by the American College of Rheumatology.

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.

[Doppler ultrasound evaluation of aortic insufficiency using half-pressure time. Absence of arterial rigidity influence].

PubMed

Kalotka-Bratek, H; Drobinski, G; Klimczak, K; Busquet, P; Fraysse, J B; Bejean-Lebuisson, A; Grosgogeat, Y

1989-02-01

In 20 patients with pure aortic regurgitation we studied the relationship between the severity of regurgitation, as assessed haemodynamically by the percentage of leakage (%L), and the half-pressure (T 1/2 P) and half-velocity (T 1/2 V) times, as obtained from doppler aortic blood velocity curves, taking into account the rigidity of the systemic vascular circuit characterized by the pressure wave propagation velocity (PWPV). The systemic arterial circuit was supple in 14 patients (PWPV less than 7.5 m/sec) and rigid in 6 patients (PWPV greater than 7.5 m/sec). The regression slopes between %L and T 1/2 P and between %L and T 1/2 V were calculated with their confidence limits in the 14 patients with supple arteries. The 6 patients with rigid arteries fitted into this nomogram, thus demonstrating that systemic arterial rigidity makes no difference in the relationship between %L and doppler indices. The half-velocity and half-pressure times measured by doppler ultrasound were acquired from a velocity signal directly determined by the aortic regurgitation, without any detectable effect of vascular circuit rigidity. Being equivalent by nature to the signal decrease time constant, they are independent of the absolute protodiastolic value of diastolic pressure gradient or blood flow velocity. For this reason these two doppler parameters are reliable to evaluate the severity of aortic regurgitation.

Cloud fraction and cloud base measurements from scanning Doppler lidar during WFIP-2

NASA Astrophysics Data System (ADS)

Bonin, T.; Long, C.; Lantz, K. O.; Choukulkar, A.; Pichugina, Y. L.; McCarty, B.; Banta, R. M.; Brewer, A.; Marquis, M.

2017-12-01

The second Wind Forecast Improvement Project (WFIP-2) consisted of an 18-month field deployment of a variety of instrumentation with the principle objective of validating and improving NWP forecasts for wind energy applications in complex terrain. As a part of the set of instrumentation, several scanning Doppler lidars were installed across the study domain to primarily measure profiles of the mean wind and turbulence at high-resolution within the planetary boundary layer. In addition to these measurements, Doppler lidar observations can be used to directly quantify the cloud fraction and cloud base, since clouds appear as a high backscatter return. These supplementary measurements of clouds can then be used to validate cloud cover and other properties in NWP output. Herein, statistics of the cloud fraction and cloud base height from the duration of WFIP-2 are presented. Additionally, these cloud fraction estimates from Doppler lidar are compared with similar measurements from a Total Sky Imager and Radiative Flux Analysis (RadFlux) retrievals at the Wasco site. During mostly cloudy to overcast conditions, estimates of the cloud radiating temperature from the RadFlux methodology are also compared with Doppler lidar measured cloud base height.

The use of breast ultrasound color Doppler vascular pattern morphology improves diagnostic sensitivity with minimal change in specificity.

PubMed

Svensson, W E; Pandian, A J; Hashimoto, H

2010-10-01

The aim of this study was to evaluate the use of vascular morphology, around and within the B-mode region of abnormality, for improving the diagnostic accuracy of two of the most common solid breast pathologies. The B-mode and Doppler images of 117 breast cancers and 366 fibroadenomas and lesions with a fibroadenoma-like appearance were reviewed retrospectively and the morphology of the vascular pattern was evaluated. The ratio of external to internal color Doppler, the external vascular pattern and the connecting vessels to internal vessels were assessed and differentiated into benign and malignant vascular patterns. These patterns were correlated with the histological diagnosis. Vascularity was demonstrated in 95 % of cancers and in 46 % of benign lesions with a trend to increasing vascularity in cancers. This provided poor specificity for excluding cancer in fibroadenomas. Variations in vascular pattern were recorded. The observed benign vascular patterns were avascularity, vascularity in the periphery and peripheral marginal vessels connecting with internal vascularity. The observed malignant vascular patterns were radially aligned external vessels with internal vessels being more numerous than external vessels which connected to radial vessels. (Fisher exact test p < 0.0001). Analysis of the vascular morphology improved the sensitivity for identifying cancers from 97 % (B-mode) to 99 % (B-mode and color Doppler) with a minimal reduction in specificity (93.7 to 92.6 %) or accuracy (94.6 to 94.2 %). The presence of vascularity within a lesion, by itself, is no longer a good predictor of malignancy because of the increase in Doppler sensitivity associated with improvements in ultrasound technology. The color Doppler ultrasound vascular pattern morphology improves the accuracy and sensitivity of B-mode image diagnosis, breast cancers and fibroadenomas with a minimal loss of specificity. Any breast lesion with radial rather than marginal connecting vessels should

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.

Medical Ultrasound Imaging.

ERIC Educational Resources Information Center

Hughes, Stephen

2001-01-01

Explains the basic principles of ultrasound using everyday physics. Topics include the generation of ultrasound, basic interactions with material, and the measurement of blood flow using the Doppler effect. (Author/MM)

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.

A Comparison of Real-time Feedback and Tissue Response to Ultrasound-Guided High Intensity Focused Ultrasound (HIFU) Ablation using Scanned Track Exposure Regimes

NASA Astrophysics Data System (ADS)

Gray, Robert H. R.; Leslie, Thomas A.; Civale, John; Kennedy, James E.; ter Haar, Gail

2007-05-01

Real time ultrasound monitoring of tissue ablation in clinical HIFU treatments currently depends on the observation of the appearance of new hyperechoic regions within the target volume, allowing visually directed treatment. These grey-scale changes are attributed to the formation of gas or vapour bubbles. In this study, scanned track lesions have been formed in ex vivo bovine liver samples at a range of ablative intensities (free field spatial peak intensities 7 - 47 kW cm-2), and tracking speeds (1-2 mms-1). Their appearance on conventional B-mode ultrasound images has been assessed using digital imaging techniques over the first 60 seconds following HIFU exposure. The size of the lesion as seen on the ultrasound scan is compared to the macroscopic size of the lesion at dissection. It is seen that the lesion size is highly dependent on the intensity and scanning speed of the transducer. Reliable lesions can be created using scanned tracks at the lowest powers, with increased numbers of cycles, and grey-scale changes correlated strongly with the histological findings. Although not a highly sensitive indication of ablated area, ultrasound monitoring of treatment is highly specific thus confirming its clinical utility.

Ultrasound-Diagnosed Tibia Stress Fracture: A Case Report.

PubMed

Amoako, Adae; Abid, Ayesha; Shadiack, Anthony; Monaco, Robert

2017-01-01

Stress fractures are a frequent cause of lower extremity pain in athletes, and especially in runners. Plain imaging has a low sensitivity. Magnetic resonance imaging (MRI) or bone scan scintigraphy is the criterion standard, but expensive. We present the case of a young female distance runner with left shin pain. Plain radiography was unremarkable. Ultrasound showed focal hyperechoic elevation of the periosteum with irregularity over the distal tibia and increased flow on Doppler. These findings were consistent with a distal tibia stress fracture and confirmed by MRI. Examination of our case will highlight the utility of considering an ultrasound for diagnosis of tibial stress fracture.

Ultrasound-Diagnosed Tibia Stress Fracture: A Case Report

PubMed Central

Amoako, Adae; Abid, Ayesha; Shadiack, Anthony; Monaco, Robert

2017-01-01

Stress fractures are a frequent cause of lower extremity pain in athletes, and especially in runners. Plain imaging has a low sensitivity. Magnetic resonance imaging (MRI) or bone scan scintigraphy is the criterion standard, but expensive. We present the case of a young female distance runner with left shin pain. Plain radiography was unremarkable. Ultrasound showed focal hyperechoic elevation of the periosteum with irregularity over the distal tibia and increased flow on Doppler. These findings were consistent with a distal tibia stress fracture and confirmed by MRI. Examination of our case will highlight the utility of considering an ultrasound for diagnosis of tibial stress fracture. PMID:28469488

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

Studies on the foundation and development of diagnostic ultrasound

PubMed Central

Wagai, Toshio

2007-01-01

In recent years, various types of diagnostic imaging methods, such as CT, MRI, PET and Ultrasound, have been developed rapidly and become indispensable as clinical diagnostic tools. Among these imaging modalities, CT, MRI and PET all apply electromagnetic waves like radiation rays. In contrast, an ultrasound imaging method uses a completely different mechanical pressure wave: “sound”. Ultrasound has various features, including inaudible sound at very high frequencies, which allows its use in medical diagnoses. That is, ultrasound techniques can be applied in transmission, reflection and Doppler methods. Moreover, the sharp directivity of an ultrasound beam can also improve image resolution. Another big advantage of diagnostic ultrasound is that it does not harm the human body or cause any pain to patients. Given these various advantages, diagnostic ultrasound has recently been widely used in diagnosing cancer and cardiovascular disease and scanning fetuses (Fig. 1) as well as routine clinical examinations in hospitals. In this paper, I outline my almost 50-year history of diagnostic ultrasound research, particularly that performed at the early stage from 1950–56. PMID:24367150

Grey-scale and colour Doppler ultrasound versus magnetic resonance imaging for the prenatal diagnosis of placenta accreta.

PubMed

Rezk, Mohamed Abd-Allah; Shawky, Mohamed

2016-01-01

To assess the effectiveness of grey-scale and colour Doppler ultrasound (US) versus magnetic resonance imaging (MRI) for the prenatal diagnosis of placenta accreta. A prospective observational study including a total of 74 patients with placenta previa and previous uterine scar (n = 74). Grey-scale and colour Doppler US was done followed by MRI by different observers to diagnose adherent placenta. Test validity of US and MRI were calculated. Maternal morbidity and mortality were also assessed. A total of 53 patients confirmed to have placenta accreta at operation. The overall sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of US was 94.34, 91.67, 96.15 and 88% compared to 96.08, 87.50, 94.23 and 91.3% for MRI, respectively. The most relevant US sign was turbulent blood flow by colour Doppler, while dark intra-placental band was the most sensitive MRI sign. Venous thromboembolism (1.3%), bladder injury (29.7%), ureteric injury (18.9%), postoperative fever (10.8%), admission to ICU (50%) and re-operation (31.1%). Placenta accreta can be successfully diagnosed by grey-scale and colour Doppler US. MRI would be more likely suggested for either posteriorly or laterally situated placenta previa in order to exclude placental invasion.

Invasive and noninvasive assessment of pulmonic regurgitation: clinical, angiographic, phonocardiographic, echocardiographic, and Doppler ultrasound correlations.

PubMed

Chandraratna, P A; Wilson, D; Imaizumi, T; Ritter, W S; Aronow, W S

1982-06-01

Three patients with pulmonic regurgitation and no evidence of pulmonary hypertension were investigated. These patients had low pitched diastolic murmurs which increased on inspiration, evidence of connective tissue disease as manifested by lax joints and hyperextensible skin, and marked hilar dance which extended up to the peripheral vessels. Suprasternal echocardiography revealed dilatation and increased systolic expansion of the right pulmonary artery (RPA) (25% and 28%, respectively) in two patients; the third patient had a normal RPA dimension in diastole and a marked increase in diameter (88%) in systole. Thus, these three patients demonstrated hyperdistensibility of the RPA. The spectral signal from the pulsed doppler echocardiograph showed evidence of turbulent blood flow in diastole (wide dispersion of the dots) in the right ventricular outflow tract in all three patients. This pattern was indicative of pulmonic regurgitation. In summary, the combined use of echocardiography and Doppler ultrasound is useful in the evaluation of patients with pulmonic regurgitation.

Staggered Multiple-PRF Ultrafast Color Doppler.

PubMed

Posada, Daniel; Poree, Jonathan; Pellissier, Arnaud; Chayer, Boris; Tournoux, Francois; Cloutier, Guy; Garcia, Damien

2016-06-01

Color Doppler imaging is an established pulsed ultrasound technique to visualize blood flow non-invasively. High-frame-rate (ultrafast) color Doppler, by emissions of plane or circular wavefronts, allows severalfold increase in frame rates. Conventional and ultrafast color Doppler are both limited by the range-velocity dilemma, which may result in velocity folding (aliasing) for large depths and/or large velocities. We investigated multiple pulse-repetition-frequency (PRF) emissions arranged in a series of staggered intervals to remove aliasing in ultrafast color Doppler. Staggered PRF is an emission process where time delays between successive pulse transmissions change in an alternating way. We tested staggered dual- and triple-PRF ultrafast color Doppler, 1) in vitro in a spinning disc and a free jet flow, and 2) in vivo in a human left ventricle. The in vitro results showed that the Nyquist velocity could be extended to up to 6 times the conventional limit. We found coefficients of determination r(2) ≥ 0.98 between the de-aliased and ground-truth velocities. Consistent de-aliased Doppler images were also obtained in the human left heart. Our results demonstrate that staggered multiple-PRF ultrafast color Doppler is efficient for high-velocity high-frame-rate blood flow imaging. This is particularly relevant for new developments in ultrasound imaging relying on accurate velocity measurements.

[The development and utility of new uroflowmetry measurement by wearable airborne ultrasound Doppler system].

PubMed

Matsumoto, Seiji; Kakizaki, Hidehiro

2012-09-01

The conventional concept of uroflowmetry (UFM) is to equip the urine-receiving container like a toilet device (s) with various sensors. A UFM device based on an airborne ultrasound continuous wave Doppler system was developed to satisfy the need of measuring urinary flow anytime and anywhere in an easy, natural, and repeated manner. It is a non-contact, indirect measuring device that can be easily worn by the test subjects who urinate. The prototype of the new UFM device was used to collect urination data from normal adult volunteers. Data could be collected with the new UFM device, and the Doppler spectrum (urination pattern) could be evaluated in chronological order for each volunteer's urination. It was confirmed from the examination of effectiveness that there is a potential for the clinical application of the new device, but at the present stage it is not yet clinically applicable. The results obtained suggest that the device may greatly change the concept of urodynamics, depending on future progress. However, accuracy in collecting samples and analyzing data will have to be further improved using the latest engineering technology.

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

Doppler ultrasound-based measurement of tendon velocity and displacement for application toward detecting user-intended motion.

PubMed

Stegman, Kelly J; Park, Edward J; Dechev, Nikolai

2012-07-01

The motivation of this research is to non-invasively monitor the wrist tendon's displacement and velocity, for purposes of controlling a prosthetic device. This feasibility study aims to determine if the proposed technique using Doppler ultrasound is able to accurately estimate the tendon's instantaneous velocity and displacement. This study is conducted with a tendon mimicking experiment consisting of two different materials: a commercial ultrasound scanner, and a reference linear motion stage set-up. Audio-based output signals are acquired from the ultrasound scanner, and are processed with our proposed Fourier technique to obtain the tendon's velocity and displacement estimates. We then compare our estimates to an external reference system, and also to the ultrasound scanner's own estimates based on its proprietary software. The proposed tendon motion estimation method has been shown to be repeatable, effective and accurate in comparison to the external reference system, and is generally more accurate than the scanner's own estimates. After establishing this feasibility study, future testing will include cadaver-based studies to test the technique on the human arm tendon anatomy, and later on live human test subjects in order to further refine the proposed method for the novel purpose of detecting user-intended tendon motion for controlling wearable prosthetic devices.

3D model assisted fully automated scanning laser Doppler vibrometer measurements

NASA Astrophysics Data System (ADS)

Sels, Seppe; Ribbens, Bart; Bogaerts, Boris; Peeters, Jeroen; Vanlanduit, Steve

2017-12-01

In this paper, a new fully automated scanning laser Doppler vibrometer (LDV) measurement technique is presented. In contrast to existing scanning LDV techniques which use a 2D camera for the manual selection of sample points, we use a 3D Time-of-Flight camera in combination with a CAD file of the test object to automatically obtain measurements at pre-defined locations. The proposed procedure allows users to test prototypes in a shorter time because physical measurement locations are determined without user interaction. 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. The proposed method is illustrated with vibration measurements of an unmanned aerial vehicle

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.

Non-invasive assessment of fibrosis using color Doppler ultrasound in patients with hepatitis C virus in the Amazon rainforest, Brazil.

PubMed

Leão, Jorge; Brock, Marianna; Castilho, Márcia; Scariot, André; Scariot, Ana; Braga, Wornei

2012-02-01

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.

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

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.

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.

Wave Field Characterization Using Dual-Polarized Pulse-Doppler X-Band Radar

DTIC Science & Technology

2012-06-01

spectrum (frequencies higher than that associated with the wind wave peak) are similar for the buoy and Doppler, and likewise for the ultrasound array and...values of the RCS and ultrasound array relative to the buoy and Doppler are due to the formers’ larger energy levels at high frequencies. NSWCCD-50-TR...pp. 199- 203, 2008. [II] W. J. Plant, W. C. Keller, A. B. Reeves, E. A. Uliana, and J. W. Johnson, " Airborne microwave Doppler measurements of

3D power Doppler ultrasound assessment of placental perfusion during uterine contraction in labor.

PubMed

Sato, Miki; Noguchi, Junko; Mashima, Masato; Tanaka, Hirokazu; Hata, Toshiyuki

2016-09-01

To assess placental perfusion during spontaneous or induced uterine contraction in labor at term using placental vascular sonobiopsy (PVS) by 3D power Doppler ultrasound with the VOCAL imaging analysis program. PVS was performed in 50 normal pregnancies (32 in spontaneous labor group [SLG], and 18 in induced labor group with oxytocin or prostaglandin F2α [ILG]) at 37-41 weeks of gestation to assess placental perfusion during uterine contraction in labor. Only pregnancies with an entirely visualized anterior placenta were included in the study. Data acquisition was performed before, during (at the peak of contraction), and after uterine contraction. 3D power Doppler indices such as the vascularization index (VI), flow index (FI), and vascularization flow index (VFI) were calculated in each placenta. There were no abnormal fetal heart rate tracings during contraction in either group. VI and VFI values were significantly reduced during uterine contraction in both groups (SLG, -33.4% [-97.0-15.2%], and ILG, -49.6% [-78.2--4.0%]), respectively (P < 0.001). The FI value in the ILG group was significantly lower during uterine contraction (P = 0.035), whereas it did not change during uterine contraction in the SLG group. After uterine contraction, all vascular indices returned almost to the same level as that before uterine contraction. However, the FI value in ILG (-8.6%, [-19.7-16.0%]) was significantly lower than that in SLG (2.4%, [-13.4-38.1%]) after uterine contraction (P < 0.05). All 3D power Doppler indices (VI, FI, and VFI) during uterine contraction (at the peak of contraction) showed a correlation greater than 0.7, with good intra- and inter-observer agreements. Our findings suggest that uterine contraction in both spontaneous and induced labors causes a significant reduction in placental perfusion. Reduced placental blood flow in induced uterine contraction has a tendency to be marked compared with that in spontaneous uterine contraction. To the best of

Assessment of ureterovesical jet dynamics in obstructed ureter by urinary stone with color Doppler and duplex Doppler examinations.

PubMed

Jandaghi, Ali Babaei; Falahatkar, Siavash; Alizadeh, Ahmad; Kanafi, Alireza Rajabzadeh; Pourghorban, Ramin; Shekarchi, Babak; Zirak, Amin Keshavarz; Esmaeili, Samaneh

2013-04-01

This study was designed to evaluate ureterovesical jet dynamics in obstructed ureter and to compare it with those of contralateral unobstructed side. Forty-six patients with diagnosis of ureteral stone, based on imaging findings in computed tomography were enrolled in this study. The gray-scale ultrasound exam from both kidneys and urinary bladder was performed. Then, ureterovesical jet characteristics including ureteral jet frequency, duration and peak velocity were assessed by color Doppler and duplex Doppler studies in both obstructed and unobstructed ureters by a radiologist, 15-30 min after oral hydration with 750-1,000 mL of water. When compared with contralateral normal side, the ureterovesical jet in obstructed ureter showed less frequency (0.59 vs. 3.04 jets/min; P < 0.05), shorter duration (1.24 vs. 5.26 s; P < 0.05) and lower peak velocity (5.41 vs. 32.09 cm/s; P < 0.05). The cut-off points of 1.5 jets/min, 2.5 s and 19.5 cm/s for difference of ureteral jet frequency, duration and peak velocity between obstructed and contralateral normal ureters yielded sensitivities of 97.8, 95.6 and 100 % and specificities of 87, 87.9 and 97.8 %, respectively for diagnosis of ureteral obstruction. Given the safety of Doppler study and significant differences in flow dynamics of obstructed versus unobstructed ureters, our findings demonstrated the utility of Doppler ultrasound examination as a useful adjunct to gray-scale ultrasound by improving the accuracy of ultrasound exam in diagnosis of ureteral obstruction.

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

PubMed

Gaschen, Lorrie; Kircher, Patrick

2007-08-01

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

Variation of safety indices during in the learning curve for color Doppler assessment of the fetal heart at 11+0 to 13+6 weeks' gestation.

PubMed

Nemescu, Dragos; Berescu, Anca; Rotariu, Cristian

2015-12-01

The aim of our study was to analyze the variation of acoustic output, as expressed by the thermal (TI) and mechanical index (MI), during the learning curve for a fetal heart scan at 11-13 gestational weeks, with the introduction of a new ultrasound system. This was a prospective, observational study on 303 normal fetuses. The fetal heart was examined transabdominally using B-Mode and high definition (HD) color Doppler to obtain standard parameters: four-chamber, outflow tracts and three-vessel-trachea views. Data were analyzed in groups of 20 consecutive examinations and the percentage of successful examinations was calculated. TI and MI were retrieved from HD color Doppler examinations of the fetal heart and from pulsed-wave Doppler assessment of the tricuspid flow and ductus venosus. MI values from the color Doppler examination of the fetal heart showed a continuous decrease (0.81 to 0.75, p<0.001), along the learning phase. TI and MI indices from pulsed-wave Doppler evaluation of the tricuspid flow increased at the beginning of the learning phase and stabilized afterwards (0.34 to 0.36, p<0.05 and 0.37 to 0.4, p<0.001, respectively). TI from color Doppler exam of the heart and indices from ductus venosus assessment were very constant and did not change along the studied periods. The length of Doppler examination of the heart increased after about 80 cases by 25%, to a mean of 4 minutes (p<0.05). Safety indices from Doppler evaluation of the fetal heart and tricuspid flow vary during the learning curve for fetal heart assessment. Also, the occurrence of constant values suggests the potential for their supplementary active reduction. For a better adaptation to a new ultrasound technology, the sonographer should scan the fetal heart longer in the first trimester and follow displayed safety indices along the first 80 cases.

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.

A comparison of cell-free placental messenger ribonucleic acid and color Doppler ultrasound for the prediction of placental invasion in patients with placenta accreta.

PubMed

Naghshineh, Elham; Khorvash, Elahe; Kamali, Sara

2015-01-01

The aim of the present study was to comparison between cell-free placental messenger ribonucleic acid (mRNA) and Doppler ultrasound for the prediction of placental invasion in women with placenta accreta. In this cross-sectional study, 50 pregnant women at risk for placenta accreta underwent color Doppler and assessment of cell-free placental mRNA. Real-time reverse-transcription polymerase chain reaction was used for measurement of cell-free placental mRNA in maternal plasma. Based on the findings at cesarean delivery and histological examination, patients were divided into two groups of women with and without placenta accrete. To compare of the mean of mRNA levels between the two groups we used independent t-test and to compare of the mean of age and gestational age at sonography we used Mann-Whitney test. For determination of sensitivity and specificity and the cut-off point of mRNA levels we used the receiver operating characteristic curve. A total of 50 women with a mean age of 30.24 ± 4.905 years entered the study and 12 (24%) patients were diagnosed with placenta accreta. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of Doppler ultrasound were 83.3%, 78.9%, 56% and 94%, respectively. Results of our study showed if we consider a cut-off point equal to 3.325, with sensitivity and specificity of 0.917 and 0.789, respectively and the sensitivity, specificity, PPV and NPV of mRNA with were cut-off point of 3.325 were 91.7%, 78.9%, 57.9% and 96.8%, respectively. Cell-free mRNA is an acceptable, easy made, functional test with sensitivity, specificity, PPV and NPV more than Doppler ultrasound for diagnosis and prediction of incidence of placenta accrete and we recommend the use of cell-free mRNA test for diagnosis of placenta accreta.

WE-B-210-02: The Advent of Ultrafast Imaging in Biomedical Ultrasound

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanter, M.

In the last fifteen years, the introduction of plane or diverging wave transmissions rather than line by line scanning focused beams has broken the conventional barriers of ultrasound imaging. By using such large field of view transmissions, the frame rate reaches the theoretical limit of physics dictated by the ultrasound speed and an ultrasonic map can be provided typically in tens of micro-seconds (several thousands of frames per second). Interestingly, this leap in frame rate is not only a technological breakthrough but it permits the advent of completely new ultrasound imaging modes, including shear wave elastography, electromechanical wave imaging, ultrafastmore » doppler, ultrafast contrast imaging, and even functional ultrasound imaging of brain activity (fUltrasound) introducing Ultrasound as an emerging full-fledged neuroimaging modality. At ultrafast frame rates, it becomes possible to track in real time the transient vibrations – known as shear waves – propagating through organs. Such “human body seismology” provides quantitative maps of local tissue stiffness whose added value for diagnosis has been recently demonstrated in many fields of radiology (breast, prostate and liver cancer, cardiovascular imaging, …). Today, Supersonic Imagine company is commercializing the first clinical ultrafast ultrasound scanner, Aixplorer with real time Shear Wave Elastography. This is the first example of an ultrafast Ultrasound approach surpassing the research phase and now widely spread in the clinical medical ultrasound community with an installed base of more than 1000 Aixplorer systems in 54 countries worldwide. For blood flow imaging, ultrafast Doppler permits high-precision characterization of complex vascular and cardiac flows. It also gives ultrasound the ability to detect very subtle blood flow in very small vessels. In the brain, such ultrasensitive Doppler paves the way for fUltrasound (functional ultrasound imaging) of brain activity with

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

Diagnostic utility of three-dimensional power Doppler ultrasound for postmenopausal bleeding.

PubMed

Kim, Ari; Lee, Ji Young; Chun, Sungwook; Kim, Heung Yeol

2015-06-01

We evaluated the role of three-dimensional power Doppler ultrasound (3D PD-US) to detect endometrial lesions in women with postmenopausal endometrial bleeding. In this prospective observational study, from January 2009 to November 2012, we recruited 225 postmenopausal women with postmenopausal uterine bleeding who met the study criteria. Women who had hematologic disease, chronic medical diseases, or nonuterine pelvic diseases were excluded. Prior to endometrial biopsy, the patients underwent a baseline transvaginal ultrasound screening. The vascular indices and endometrial volumes were calculated with 3D PD-US and compared with the endometrial histopathology. Among the endometrial histopathologic findings of 174 women, atrophic endometrium was the most common finding (30.5%). Endometrial malignancy was confirmed in 28 cases (16.1%), and endometrial hyperplasia was diagnosed in 17 cases (9.8%). The prevalence of endometrial cancer was high in patients who had endometrial thickness >9.5 mm (p < 0.001) and volume greater than 4.05 mL (p < 0.001). For the endometrial carcinoma only, the cutoff values of vascular index, flow index, and vascular flow index for predicting malignancy were 13.070, 12.610, and 3.764, respectively. For endometrial hyperplasia, endometrial thickness and vascular flow index were significant findings. Endometrial vasculature and volume can be obtained using 3D PD-US. The diagnostic usefulness of 3D PD-US for endometrial diseases is promising in women with postmenopausal endometrial bleeding. Copyright © 2015. Published by Elsevier B.V.

The value of Doppler ultrasound in predicting delayed graft function occurrence after kidney transplantation.

PubMed

Mocny, Grzegorz; Bachul, Piotr; Chang, Ea-Sle; Kulig, Piotr

The aim of this study was to assess the predictive value of blood flow velocity and vascular resistance measured by Doppler ultrasound in terms of pulsatility index (PI) and resistive index (RI) respectively, in the occurrence of delayed graft function (DGF) after kidney transplantation. This prospective study enrolled kidney transplant recipients operated from January 2005 to April 2009 in the 1st Department of General, Oncological and Gastroenterological Surgery, Jagiellonian University Medical College, Kraków, Poland. The medical records of 53 kidney transplant recipients from deceased donors were reviewed. PI and RI values of the graft arcuate artery were calculated immediately after blood flow restoration and on the 1st, 2nd, 4th and 8th post-operative day. DGF was observed in 20 patients (37.7%), while 33 patients (62.3%) had immediate restoration of the kidney function. The mean intraoperative values of RI and PI from patients with DGF were significantly higher in comparison to patients without DGF (0.9 vs. 0.74, p <0.001; 1.76 vs. 1.54, p = 0.019, respectively). Post-operatively, the RI and PI values remained stable and significantly higher in DGF group. The highest sensitivity of RI to predict DGF occurrence was observed intraoperatively and on the first postoperative day, with values of 77.8% and 72.2%, respectively. The risk of DGF occurrence with intraoperative RI value ≥0.9 increased by 13-fold, and with intraoperative PI value ≥1.9 by 12-fold. This increase was even more prominent during the first post-operative day with RI value ≥0.9 or PI value ≥1.9 with 19-fold increase in the risk of DGF occurrence. According to our study, the utilization of Doppler ultrasound with measurement of hemodynamic parameters (PI, RI), play a crucial role in predicting the outcomes of kidney transplantation.

Assessment by three-dimensional power Doppler ultrasound of cerebral blood flow perfusion in fetuses with congenital heart disease.

PubMed

Zeng, S; Zhou, J; Peng, Q; Tian, L; Xu, G; Zhao, Y; Wang, T; Zhou, Q

2015-06-01

To use three-dimensional (3D) power Doppler ultrasound to investigate cerebral blood flow perfusion in fetuses with congenital heart disease (CHD). The vascularization index (VI), flow index (FI) and vascularization flow index (VFI) in the total intracranial volume and the main arterial territories (middle cerebral artery (MCA), anterior cerebral artery (ACA) and posterior cerebral artery (PCA)) were evaluated prospectively and compared in 112 fetuses with CHD and 112 normal fetuses using 3D power Doppler. Correlations between the 3D power Doppler indices and neurodevelopment scores at 12 months of age were assessed in a subset of the CHD group, and values were compared with those of controls. Compared with the controls, the VI, FI and VFI of the total intracranial volume and the three main arteries were significantly higher in fetuses with hypoplastic left heart syndrome and left-sided obstructive lesions (P < 0.001), and the 3D power Doppler values in the ACA territory were significantly higher in fetuses with transposition of the great arteries (P < 0.01). The largest proportional increase in the blood flow perfusion indices in the fetuses with CHD relative to controls was observed in the ACA territory (P < 0.05). Among 41 cases with CHD that underwent testing, the mean Psychomotor Development Index (PDI) and Mental Development Index (MDI) scores were significantly lower than in 94 of the controls that were tested (P < 0.001). Among these CHD cases, total intracranial FI was positively correlated with PDI (r = 0.342, P = 0.029) and MDI (r = 0.339, P = 0.030), and ACA-VI and ACA-VFI were positively correlated with PDI (r = 0.377 and 0.389, P = 0.015 and 0.012, respectively) but were not correlated with MDI (r = 0.243 and 0.203, P = 0.126 and 0.204, respectively). Cerebral blood flow perfusion was increased relative to controls in most fetuses with CHD and was associated with neurodevelopment scores at 12 months

Estimation of Measurement Characteristics of Ultrasound Fetal Heart Rate Monitor

NASA Astrophysics Data System (ADS)

Noguchi, Yasuaki; Mamune, Hideyuki; Sugimoto, Suguru; Yoshida, Atsushi; Sasa, Hidenori; Kobayashi, Hisaaki; Kobayashi, Mitsunao

1995-05-01

Ultrasound fetal heart rate monitoring is very useful to determine the status of the fetus because it is noninvasive. In order to ensure the accuracy of the fetal heart rate (FHR) obtained from the ultrasound Doppler data, we measure the fetal electrocardiogram (ECG) directly and obtain the Doppler data simultaneously. The FHR differences of the Doppler data from the direct ECG data are concentrated at 0 bpm (beats per minute), and are practically symmetrical. The distribution is found to be very close to the Student's t distribution by the test of goodness of fit with the chi-square test. The spectral density of the FHR differences shows the white noise spectrum without any dominant peaks. Furthermore, the f-n (n>1) fluctuation is observed both with the ultrasound Doppler FHR and with the direct ECG FHR. Thus, it is confirmed that the FHR observation and observation of the f-n (n>1) fluctuation using the ultrasound Doppler FHR are as useful as the direct ECG.

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.

Role of 3D Ultrasound and Doppler in Differentiating Clinically Suspected Cases of Leiomyoma and Adenomyosis of Uterus

PubMed Central

Sharma, Kaveri; Venkatesh, B.P; Barman, Partho; Roy, Sumit Kumar; Jayagurunathan, Usha; Sellamuthu, Eswaramoorthy; Moidu, Fazil

2015-01-01

Introduction Adenomyosis and Leiomyoma are common disorders affecting females in their reproductive age. They mimic each other in clinical presentation. Due to similarities in clinical symptoms and signs, missing one diagnosis in favour of the other is not very uncommon. Accurate diagnosis of these two conditions is important for their management. In this study we evaluated role of 3D Ultrasound and Doppler in differentiating clinically suspected cases of leiomyoma and adenomyosis of uterus. Materials and Methods A total of 100 patients with symptoms of abnormal uterine bleeding (with or without dysmenorrhoea), lump abdomen, chronic pelvic pain or dysparaunia who were clinically diagnosed as leiomyoma of uterus and/or adenomyosis were enrolled in to the study. These patients underwent transvaginal sonography (TVS), trans abdominal sonography (TAS) along with color and spectral Doppler sonography. Scanning was done in follicular phase of the menstrual cycle to avoid bias due high vascularity of endometrium in secretory phase. The morphology of the lesion, its vascularity, and Pulsality Index (PI), Resistive Index (RI) and Vmax (maximum velocity) were measured. Only those patients who were chosen for operative treatment were included in the study. Radiological diagnosis was then correlated with intra-operative and histopathological diagnosis. Results On imaging, while using morphological criteria and Doppler for diagnosing leiomyoma, it was found that “peripheral vascularity” was seen in 52 (89%) cases, which was the highest. Similarly while diagnosing adenomyosis it was, the criteria “central vascularity” was seen in 28 cases (93%) and “ill defined junctional zone in 3D ultrasound” was seen in 26 cases (86%), which was also observed to be highest. With the cut off values taken for PI,RI and Vmax, diagnosis of leiomyoma was found to be 93.4% sensitive, 95.6% specific and with a positive predictive value of 97.6% and negative predictive value of 88

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.

Use of ultrasound imaging for the diagnosis of abnormal uterine bleeding in the bonnet macaque ( Macaca radiata).

PubMed

Chaudhari, Uddhav K; Imran, M; Manjramkar, Dhananjay D; Metkari, Siddhanath M; Sable, Nilesh P; Gavhane, Dnyaneshwar S; Katkam, Rajendra R; Sachdeva, Geetanjali; Thakur, Meenakshi H; Kholkute, Sanjeeva D

2017-02-01

Ultrasound is a powerful, low-cost, non-invasive medical tool used by laboratory animal veterinarians for diagnostic imaging. Sonohysterography and transvaginal ultrasound are frequently used to assess uterine anomalies in women presenting with abnormal uterine bleeding (AUB). In the present study, we have evaluated the abdominal ultrasound of bonnet monkeys ( n = 8) showing spontaneous ovulatory ( n = 5) and anovulatory ( n = 3) AUB. The ovulatory ( n = 5) macaques showed cyclic AUB for 7-8 days. The anovulatory ( n = 3) macaques had irregular AUB with menstrual cycles of 40-45 days. The B-mode abdominal, colour Doppler and 3D ultrasound scans were performed during the proliferative phase of the menstrual cycle. Ultrasound examination revealed endometrial polyps in five macaques and endometrial hyperplasia in three animals. The width and length of endometrial polyps was around 0.5-1 cm (average 0.51 ± 0.23 cm × 0.96 ± 0.16 cm) with significant increase in endometrial thickness ( P < 0.0002). 3D ultrasound also showed a homogeneous mass in the uterine cavity and colour Doppler ultrasound showed increased vascularity in the endometrial polyps. Endometrial hyperplasia characteristically appeared as a thickened echogenic endometrium ( P < 0.0002). This study demonstrates the use of non-invasive ultrasound techniques in the diagnosis of AUB in macaques.

Monitoring and Quantifying Particles Emissions around Industrial Sites with Scanning Doppler Lidar

NASA Astrophysics Data System (ADS)

Thobois, L.; Royer, P.; Parmentier, R.; Brooks, M.; Knoepfle, A.; Alexander, J.; Stidwell, P.; Kumar, R.

2018-04-01

Scanning Coherent Doppler Lidars have been used over the last decade for measuring wind for applications in wind energy [1], meteorology [2] and aviation [3]. They allow for accurate measurements of wind speeds up to a distance of 10 km based on the Doppler shift effect of aerosols. The signal reflectivity (CNR or Carrier-to-Noise Ratio) profiles can also be retrieved from the strength of the Lidar signal. In this study, we will present the developments of algorithm for retrieving aerosol optical properties like the relative attenuated backscatter coefficient and the mass concentration of particles. The use of these algorithms during one operational trial in Point Samson, Western Australia to monitor fugitive emissions over a mine will be presented. This project has been initiated by the Australian Department of Environment Regulations to better determine the impact of the Port on the neighboring town. During the trial in Summer, the strong impact of turbulence refractive index on Lidar performances has been observed. Multiple methodologies have been applied to reduce this impact with more or less success. At the end, a dedicated setup and configuration have been established that allow to properly observe the plumes of the mine with the scanning Lidar. The Lidar data has also been coupled to beta attenuation in-situ sensors for retrieving mass concentration maps. A few case of dispersion of plumes will be presented showing the necessity to combine both the wind and aerosol data.

Application of scanning laser Doppler vibrometry for delamination detection in composite structures

NASA Astrophysics Data System (ADS)

Kudela, Pawel; Wandowski, Tomasz; Malinowski, Pawel; Ostachowicz, Wieslaw

2017-12-01

In this paper application of scanning laser Doppler vibrometry for delamination detection in composite structures was presented. Delamination detection was based on a guided wave propagation method. In this papers results from numerical and experimental research were presented. In the case of numerical research, the Spectral Element Method (SEM) was utilized, in which a mesh was composed of 3D spectral elements. SEM model included also a piezoelectric transducer. In the experimental research guided waves were excited using the piezoelectric transducer whereas the sensing process was conducted using scanning laser Doppler vibrometer (SLDV). Analysis of guided wave propagation and its interaction with delamination was based on a full wavefield approach. Attention was focused on interactions of guided waves with delamination manifested by A0 mode reflection, A0 mode entrapment, and S0/A0 mode conversion. Delamination was simulated by a teflon insert located between plies of composite material. Results of interaction with symmetrically and nonsymmetrical placed delamination (in respect to the composite sample thickness) were presented. Moreover, the authors investigated different size of delaminations. Damage detection was based on a new signal processing algorithm proposed by the authors. In this approach the weighted RMS was utilized selectively. It means that the summation in RMS formula was performed only for a specially selected time instances. Results for simple composite panels, panel with honeycomb core, and real stiffened composite panel from the aircraft were presented.

Perfusion dynamics assessment with Power Doppler ultrasound in skeletal muscle during maximal and submaximal cycling exercise.

PubMed

Heres, H M; Schoots, T; Tchang, B C Y; Rutten, M C M; Kemps, H M C; van de Vosse, F N; Lopata, R G P

2018-06-01

Assessment of limitations in the perfusion dynamics of skeletal muscle may provide insight in the pathophysiology of exercise intolerance in, e.g., heart failure patients. Power doppler ultrasound (PDUS) has been recognized as a sensitive tool for the detection of muscle blood flow. In this volunteer study (N = 30), a method is demonstrated for perfusion measurements in the vastus lateralis muscle, with PDUS, during standardized cycling exercise protocols, and the test-retest reliability has been investigated. Fixation of the ultrasound probe on the upper leg allowed for continuous PDUS measurements. Cycling exercise protocols included a submaximal and an incremental exercise to maximal power. The relative perfused area (RPA) was determined as a measure of perfusion. Absolute and relative reliability of RPA amplitude and kinetic parameters during exercise (onset, slope, maximum value) and recovery (overshoot, decay time constants) were investigated. A RPA increase during exercise followed by a signal recovery was measured in all volunteers. Amplitudes and kinetic parameters during exercise and recovery showed poor to good relative reliability (ICC ranging from 0.2-0.8), and poor to moderate absolute reliability (coefficient of variation (CV) range 18-60%). A method has been demonstrated which allows for continuous (Power Doppler) ultrasonography and assessment of perfusion dynamics in skeletal muscle during exercise. The reliability of the RPA amplitudes and kinetics ranges from poor to good, while the reliability of the RPA increase in submaximal cycling (ICC = 0.8, CV = 18%) is promising for non-invasive clinical assessment of the muscle perfusion response to daily exercise.

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.

Photoacoustic Doppler effect from flowing small light-absorbing particles.

PubMed

Fang, Hui; Maslov, Konstantin; Wang, Lihong V

2007-11-02

From the flow of a suspension of micrometer-scale carbon particles, the photoacoustic Doppler shift is observed. As predicted theoretically, the observed Doppler shift equals half of that in Doppler ultrasound and does not depend on the direction of laser illumination. This new physical phenomenon provides a basis for developing photoacoustic Doppler flowmetry, which can potentially be used for detecting fluid flow in optically scattering media and especially low-speed blood flow of relatively deep microcirculation in biological tissue.

3-D ultrafast Doppler imaging applied to the noninvasive mapping of blood vessels in vivo.

PubMed

Provost, Jean; Papadacci, Clement; Demene, Charlie; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

2015-08-01

Ultrafast Doppler imaging was introduced as a technique to quantify blood flow in an entire 2-D field of view, expanding the field of application of ultrasound imaging to the highly sensitive anatomical and functional mapping of blood vessels. We have recently developed 3-D ultrafast ultrasound imaging, a technique that can produce thousands of ultrasound volumes per second, based on a 3-D plane and diverging wave emissions, and demonstrated its clinical feasibility in human subjects in vivo. In this study, we show that noninvasive 3-D ultrafast power Doppler, pulsed Doppler, and color Doppler imaging can be used to perform imaging of blood vessels in humans when using coherent compounding of 3-D tilted plane waves. A customized, programmable, 1024-channel ultrasound system was designed to perform 3-D ultrafast imaging. Using a 32 × 32, 3-MHz matrix phased array (Vermon, Tours, France), volumes were beamformed by coherently compounding successive tilted plane wave emissions. Doppler processing was then applied in a voxel-wise fashion. The proof of principle of 3-D ultrafast power Doppler imaging was first performed by imaging Tygon tubes of various diameters, and in vivo feasibility was demonstrated by imaging small vessels in the human thyroid. Simultaneous 3-D color and pulsed Doppler imaging using compounded emissions were also applied in the carotid artery and the jugular vein in one healthy volunteer.

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.

A comparison of cell-free placental messenger ribonucleic acid and color Doppler ultrasound for the prediction of placental invasion in patients with placenta accreta

PubMed Central

Naghshineh, Elham; Khorvash, Elahe; Kamali, Sara

2015-01-01

Background: The aim of the present study was to comparison between cell-free placental messenger ribonucleic acid (mRNA) and Doppler ultrasound for the prediction of placental invasion in women with placenta accreta. Materials and Methods: In this cross-sectional study, 50 pregnant women at risk for placenta accreta underwent color Doppler and assessment of cell-free placental mRNA. Real-time reverse-transcription polymerase chain reaction was used for measurement of cell-free placental mRNA in maternal plasma. Based on the findings at cesarean delivery and histological examination, patients were divided into two groups of women with and without placenta accrete. To compare of the mean of mRNA levels between the two groups we used independent t-test and to compare of the mean of age and gestational age at sonography we used Mann-Whitney test. For determination of sensitivity and specificity and the cut-off point of mRNA levels we used the receiver operating characteristic curve. Results: A total of 50 women with a mean age of 30.24 ± 4.905 years entered the study and 12 (24%) patients were diagnosed with placenta accreta. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of Doppler ultrasound were 83.3%, 78.9%, 56% and 94%, respectively. Results of our study showed if we consider a cut-off point equal to 3.325, with sensitivity and specificity of 0.917 and 0.789, respectively and the sensitivity, specificity, PPV and NPV of mRNA with were cut-off point of 3.325 were 91.7%, 78.9%, 57.9% and 96.8%, respectively. Conclusions: Cell-free mRNA is an acceptable, easy made, functional test with sensitivity, specificity, PPV and NPV more than Doppler ultrasound for diagnosis and prediction of incidence of placenta accrete and we recommend the use of cell-free mRNA test for diagnosis of placenta accreta. PMID:25709996

3D ultrafast ultrasound imaging in vivo.

PubMed

Provost, Jean; Papadacci, Clement; Arango, Juan Esteban; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

2014-10-07

Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32  ×  32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra--and inter-observer variability.

Doppler optical coherence tomography of retinal circulation.

PubMed

Tan, Ou; Wang, Yimin; Konduru, Ranjith K; Zhang, Xinbo; Sadda, SriniVas R; Huang, David

2012-09-18

Noncontact retinal blood flow measurements are performed with a Fourier domain optical coherence tomography (OCT) system using a circumpapillary double circular scan (CDCS) that scans around the optic nerve head at 3.40 mm and 3.75 mm diameters. The double concentric circles are performed 6 times consecutively over 2 sec. The CDCS scan is saved with Doppler shift information from which flow can be calculated. The standard clinical protocol calls for 3 CDCS scans made with the OCT beam passing through the superonasal edge of the pupil and 3 CDCS scan through the inferonal pupil. This double-angle protocol ensures that acceptable Doppler angle is obtained on each retinal branch vessel in at least 1 scan. The CDCS scan data, a 3-dimensional volumetric OCT scan of the optic disc scan, and a color photograph of the optic disc are used together to obtain retinal blood flow measurement on an eye. We have developed a blood flow measurement software called "Doppler optical coherence tomography of retinal circulation" (DOCTORC). This semi-automated software is used to measure total retinal blood flow, vessel cross section area, and average blood velocity. The flow of each vessel is calculated from the Doppler shift in the vessel cross-sectional area and the Doppler angle between the vessel and the OCT beam. Total retinal blood flow measurement is summed from the veins around the optic disc. The results obtained at our Doppler OCT reading center showed good reproducibility between graders and methods (<10%). Total retinal blood flow could be useful in the management of glaucoma, other retinal diseases, and retinal diseases. In glaucoma patients, OCT retinal blood flow measurement was highly correlated with visual field loss (R(2)>0.57 with visual field pattern deviation). Doppler OCT is a new method to perform rapid, noncontact, and repeatable measurement of total retinal blood flow using widely available Fourier-domain OCT instrumentation. This new technology may improve the

Assessment of placental volume and vascularization at 11-14 weeks of gestation in a Taiwanese population using three-dimensional power Doppler ultrasound.

PubMed

Wang, Hsing-I; Yang, Ming-Jie; Wang, Peng-Hui; Wu, Yi-Cheng; Chen, Chih-Yao

2014-12-01

The placental volume and vascular indices are crucial in helping doctors to evaluate early fetal growth and development. Inadequate placental volume or vascularity might indicate poor fetal growth or gestational complications. This study aimed to evaluate the placental volume and vascular indices during the period of 11-14 weeks of gestation in a Taiwanese population. From June 2006 to September 2009, three-dimensional power Doppler ultrasound was performed in 222 normal pregnancies from 11-14 weeks of gestation. Power Doppler ultrasound was applied to the placenta and the placental volume was obtained by a rotational technique (VOCAL). The three-dimensional power histogram was used to assess the placental vascular indices, including the mean gray value, the vascularization index, the flow index, and the vascularization flow index. The placental vascular indices were then plotted against gestational age (GA) and placental volume. Our results showed that the linear regression equation for placental volume using gestational week as the independent variable was placental volume = 18.852 × GA - 180.89 (r = 0.481, p < 0.05). All the placental vascular indices showed a constant distribution throughout the period 11-14 weeks of gestation. A tendency for a reduction in the placental mean gray value with gestational week was observed, but without statistical significance. All the placental vascular indices estimated by three-dimensional power Doppler ultrasonography showed a constant distribution throughout gestation. Copyright © 2014. Published by Elsevier Taiwan.

Accuracy of three-dimensional multislice view Doppler in diagnosis of morbid adherent placenta

PubMed Central

Abdel Moniem, Alaa M.; Ibrahim, Ahmed; Akl, Sherif A.; Aboul-Enen, Loay; Abdelazim, Ibrahim A.

2015-01-01

Objective To detect the accuracy of the three-dimensional multislice view (3D MSV) Doppler in the diagnosis of morbid adherent placenta (MAP). Material and Methods Fifty pregnant women at ≥28 weeks gestation with suspected MAP were included in this prospective study. Two dimensional (2D) trans-abdominal gray-scale ultrasound scan was performed for the subjects to confirm the gestational age, placental location, and findings suggestive of MAP, followed by the 3D power Doppler and then the 3D MSV Doppler to confirm the diagnosis of MAP. Intraoperative findings and histopathology results of removed uteri in cases managed by emergency hysterectomy were compared with preoperative sonographic findings to detect the accuracy of the 3D MSV Doppler in the diagnosis of MAP. Results The 3D MSV Doppler increased the accuracy and predictive values of the diagnostic criteria of MAP compared with the 3D power Doppler. The sensitivity and negative predictive value (NPV) (79.6% and 82.2%, respectively) of crowded vessels over the peripheral sub-placental zone to detect difficult placental separation and considerable intraoperative blood loss in cases of MAP using the 3D power Doppler was increased to 82.6% and 84%, respectively, using the 3D MSV Doppler. In addition, the sensitivity, specificity, and positive predictive value (PPV) (90.9%, 68.8%, and 47%, respectively) of the disruption of the uterine serosa-bladder interface for the detection of emergency hysterectomy in cases of MAP using the 3D power Doppler was increased to 100%, 71.8%, and 50%, respectively, using the 3D MSV Doppler. Conclusion The 3D MSV Doppler is a useful adjunctive tool to the 3D power Doppler or color Doppler to refine the diagnosis of MAP. PMID:26401104

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

2017-11-01

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.

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 ...

Reproducibility and sensitivity of scanning laser Doppler flowmetry during graded changes in PO2

PubMed Central

Strenn, K.; Menapace, R.; Rainer, G.; Findl, O.; Wolzt, M.; Schmetterer, L.

1997-01-01

AIMS/BACKGROUND—Recently a commercially available scanning laser Doppler flowmeter has been produced, which provides two dimensional maps of the retinal perfusion. The aim of the present study was to investigate the reproducibility and the sensitivity of these measurements.
METHODS—16 healthy subjects were randomised to inhale different gas mixtures of oxygen and nitrogen in a double blind crossover study. The following gas mixtures of oxygen and nitrogen were administered: 100% oxygen + 0% nitrogen, 80% oxygen + 20% nitrogen, 60% oxygen + 40% nitrogen, 40% oxygen + 60% nitrogen, 30% oxygen + 70% nitrogen, 20% oxygen + 80% nitrogen, 15% oxygen + 85% nitrogen, and 10% oxygen + 90% nitrogen. Retinal haemodynamic variables and systemic haemodynamics were measured during all inhalation periods. Recordings under resting conditions were performed three times to calculate intraclass coefficients.
RESULTS—In two subjects we did not obtain technically adequate results. A dose dependent change in retinal blood flow during graded oxygen breathing was observed (p < 0.001). During 100% oxygen breathing blood flow decrease was between 29% and 33%, whereas blood flow increase was between 28% and 33% during inhalation of 10% oxygen + 90% nitrogen.
CONCLUSIONS—Scanning laser Doppler flowmetry has an acceptable reproducibility and is appropriate for description of the effect of graded changes in PO2 on retinal haemodynamics. The main problems with the system are the large zero offset, the fixation during retinal scanning, and the neglect of blood flow changes during the cardiac cycle.

 PMID:9227199

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.

Survey of ultrasound practice amongst podiatrists in the UK.

PubMed

Siddle, Heidi J; Patience, Aimie; Coughtrey, James; Mooney, Jean; Fox, Martin; Cherry, Lindsey

2018-01-01

Ultrasound in podiatry practice encompasses musculoskeletal ultrasound imaging, vascular hand-held Doppler ultrasound and therapeutic ultrasound. Sonography practice is not regulated by the Health and Care Professions Council (HCPC), with no requirement to hold a formal qualification. The College of Podiatry does not currently define ultrasound training and competencies.This study aimed to determine the current use of ultrasound, training received and mentorship received and/or provided by podiatrists using ultrasound. A quantitative study utilising a cross-sectional, on-line, single-event survey was undertaken within the UK. Completed surveys were received from 284 podiatrists; 173 (70%) use ultrasound as part of their general practice, 139 (49%) for musculoskeletal problems, 131 (46%) for vascular assessment and 39 (14%) to support their surgical practice. Almost a quarter ( n  = 62) worked for more than one organisation; 202 (71%) were employed by the NHS and/or private sector ( n  = 118, 41%).Nearly all (93%) respondents report using a hand-held vascular Doppler in their daily practice; 216 (82%) to support decisions regarding treatment options, 102 (39%) to provide diagnostic reports for other health professionals, and 34 (13%) to guide nerve blocks.Ultrasound imaging was used by 104 (37%) respondents primarily to aid clinical decision making ( n  = 81) and guide interventions (steroid injections n  = 67; nerve blocks n  = 39). Ninety-three percent stated they use ultrasound imaging to treat their own patients, while others scan at the request of other podiatrists ( n  = 28) or health professionals ( n  = 18). Few use ultrasound imaging for research ( n  = 7) or education ( n  = 2).Only 32 (11%) respondents ( n  = 20 private sector) use therapeutic ultrasound to treat patients presenting with musculoskeletal complaints, namely tendon pathologies.Few respondents (18%) had completed formal post-graduate CASE (Consortium

Refixation of Osteochondral Fractures by an Ultrasound-Activated Pin System - An Ovine In Vivo Examination Using CT and Scanning Electron Microscope.

PubMed

H, Neumann; A P, Schulz; S, Breer; A, Unger; B, Kienast

2015-01-01

Osteochondral injuries, if not treated appropriately, often lead to severe osteoarthritis of the affected joint. Without refixation of the osteochondral fragment, human cartilage only repairs these defects imperfectly. All existing refixation systems for chondral defects have disadvantages, for instance bad MRI quality in the postoperative follow-up or low anchoring forces. To address the problem of reduced stability in resorbable implants, ultrasound-activated pins were developed. By ultrasound-activated melting of the tip of these implants a higher anchoring is assumed. Aim of the study was to investigate, if ultrasound-activated pins can provide a secure refixation of osteochondral fractures comparing to conventional screw and conventional, resorbable pin osteosynthesis. CT scans and scanning electron microscopy should proovegood refixation results with no further tissue damage by the melting of the ultrasound-activated pins in comparison to conventional osteosynthesis. Femoral osteochondral fragments in sheep were refixated with ultrasound-activated pins (SonicPin™), Ethipins(®) and screws (Asnis™). The quality of the refixated fragments was examined after three month of full weight bearing by CT scans and scanning electron microscopy of the cartilage surface. The CT examination found almost no statistically significant difference in the quality of refixation between the three different implants used. Concerning the CT morphology, ultrasound-activated pins demonstrated at least the same quality in refixation of osteochondral fragments as conventional resorbable pins or screws. The scanning electron microscopy showed no major surface damage by the three implants, especially any postulated cartilage damage induced by the heat of the ultrasound-activated pin. The screws protruded above the cartilage surface, which may affect the opposingtibial surface. Using CT scans and scanning electron microscopy, the SonicPin™, the Ethipin(®) and screws were at least

[Proposal for the systematization of the elastographic study of mammary lesions through ultrasound scan].

PubMed

Fleury, Eduardo de Faria Castro; Fleury, Jose Carlos Vendramini; Oliveira, Vilmar Marques de; Rinaldi, Jose Francisco; Piato, Sebastiao; Roveda Junior, Decio

2009-01-01

Proposal of systematization for the elastographic study in the ultrasound routine. Evaluation was made of 308 patients forwarded to the breast intervention service in the CTC-Genesis from May 1, 2007 to March 1, 2008 to perform percutaneous breast biopsy. Prior to the percutaneous biopsy, an ultrasound study and an elastography were performed. Lesions were primarily analyzed and classified according to the Bi-Rads lexicon criteria by the conventional ultrasound scan (B mode). The elastography was then performed and analyzed in accordance with the systematization proposed by the authors, using images obtained during compression and after decompression of the area of interest. Lesions were classified following the system developed by the authors using a four-point scale, where scores (1) and (2) were considered benign, score (3) probably benign and score (4) suspicion of malignancy. Results obtained by the two methods were compared with the histological results using the areas within the ROC (receiver operator curves) curves. The area within the curve for elastography was of 0.952 with a confidence interval between 0.910 and 0.966, error of 0.023, and of 0.867 with a confidence interval between 0.823 and 0.903, error of 0.0333 for the ultrasound. When the areas were compared, a difference between the curves of 0.026 was observed, which was statistically significant. This work shows the systematization of the elastographic study using information obtained during compression and after decompression of the ultrasound scan sample, thus showing that elastography might enhance the assessment of risk of malignancy for lesions characterized by the ultrasound.

Use of translabial three-dimensional power Doppler ultrasound for cervical assessment before labor induction.

PubMed

Esin, Sertac; Yirci, Bulent; Yalvac, Serdar; Kandemir, Omer

2017-07-26

To compare translabial three-dimensional (3D) power Doppler ultrasound with Bishop score and transvaginal ultrasound measurements for cervical assessment before induction of labor with dinoprostone or cervical ripening balloon. Translabial cervical volume and length, vascularization indices and transvaginal cervical length were measured. Results were compared among women who had vaginal delivery at 24 h or less and more than 24 h after the insertion of the dinoprostone vaginal insert or cervical ripening balloon and among women who had vaginal delivery and cesarean delivery for failure to go into labor or failure to progress. There was no correlation between the time to delivery after a ripening agent was applied and translabial cervical volume, translabial cervical length, vascularization index (VI), flow index (FI), vascularization flow index (VFI), transvaginal cervical length and Bishop scores. The ultrasonographic measurements were no different among women who had vaginal delivery at 24 h or less and more than 24 h and among women who had vaginal delivery and cesarean delivery for failure to go into labor or failure to progress. In this study, we failed to demonstrate the superiority of translabial 3D ultrasonography over Bishop score and transvaginal ultrasonography for predicting the success of induction of labor.

Automated synovium segmentation in doppler ultrasound images for rheumatoid arthritis assessment

NASA Astrophysics Data System (ADS)

Yeung, Pak-Hei; Tan, York-Kiat; Xu, Shuoyu

2018-02-01

We need better clinical tools to improve monitoring of synovitis, synovial inflammation in the joints, in rheumatoid arthritis (RA) assessment. Given its economical, safe and fast characteristics, ultrasound (US) especially Doppler ultrasound is frequently used. However, manual scoring of synovitis in US images is subjective and prone to observer variations. In this study, we propose a new and robust method for automated synovium segmentation in the commonly affected joints, i.e. metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joints, which would facilitate automation in quantitative RA assessment. The bone contour in the US image is firstly detected based on a modified dynamic programming method, incorporating angular information for detecting curved bone surface and using image fuzzification to identify missing bone structure. K-means clustering is then performed to initialize potential synovium areas by utilizing the identified bone contour as boundary reference. After excluding invalid candidate regions, the final segmented synovium is identified by reconnecting remaining candidate regions using level set evolution. 15 MCP and 15 MTP US images were analyzed in this study. For each image, segmentations by our proposed method as well as two sets of annotations performed by an experienced clinician at different time-points were acquired. Dice's coefficient is 0.77+/-0.12 between the two sets of annotations. Similar Dice's coefficients are achieved between automated segmentation and either the first set of annotations (0.76+/-0.12) or the second set of annotations (0.75+/-0.11), with no significant difference (P = 0.77). These results verify that the accuracy of segmentation by our proposed method and by clinician is comparable. Therefore, reliable synovium identification can be made by our proposed method.

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

Advanced ultrasound applications in the assessment of renal transplants: contrast-enhanced ultrasound, elastography, and B-flow.

PubMed

Morgan, Tara A; Jha, Priyanka; Poder, Liina; Weinstein, Stefanie

2018-04-09

Ultrasound is routinely used as the first imaging exam for evaluation of renal transplants and can identify most major surgical complications and evaluate vascularity with color Doppler. Ultrasound is limited, however, in the detection of parenchymal disease processes and Doppler evaluation is also prone to technical errors. Multiple new ultrasound applications have been developed and are under ongoing investigation which could add additional diagnostic capability to the routine ultrasound exam with minimal additional time, cost, and patient risk. Contrast-enhanced ultrasound (CEUS) can be used off-label in the transplant kidney, and can assist in detection of infection, trauma, and vascular complications. CEUS also can demonstrate perfusion of the transplant assessed quantitatively with generation of time-intensity curves. Future directions of CEUS include monitoring treatment response and microbubble targeted medication delivery. Elastography is an ultrasound application that can detect changes in tissue elasticity, which is useful to diagnose diffuse parenchymal disease, such as fibrosis, otherwise unrecognizable with ultrasound. Elastography has been successfully applied in other organs including the liver, thyroid, and breast; however, it is still under development for use in the transplant kidney. Unique properties of the transplant kidney including its heterogeneity, anatomic location, and other technical factors present challenges in the development of reference standard measurements. Lastly, B-flow imaging is a flow application derived from B-mode. This application can show the true lumen size of a vessel which is useful to depict vascular anatomy and bypasses some of the pitfalls of color Doppler such as demonstration of slow flow.

A scanned focused ultrasound device for hyperthermia: numerical simulation and prototype implementation

NASA Astrophysics Data System (ADS)

Meaney, Paul M.; Raynolds, Timothy; Geimer, Shireen D.; Potwin, Lincoln; Paulsen, Keith D.

2004-07-01

We are developing a scanned focused ultrasound system for hyperthermia treatment of breast cancer. Focused ultrasound has significant potential as a therapy delivery device because it can focus sufficient heating energy below the skin surface with minimal damage to intervening tissue. However, as a practical therapy system, the focal zone is generally quite small and requires either electronic (in the case of a phased array system) or mechanical steering (for a fixed bowl transducer) to cover a therapeutically useful area. We have devised a simple automated steering system consisting of a focused bowl transducer supported by three vertically movable rods which are connected to computer controlled linear actuators. This scheme is particularly attractive for breast cancer hyperthermia where the support rods can be fed through the base of a liquid coupling tank to treat tumors within the breast while coupled to our noninvasive microwave thermal imaging system. A MATLAB routine has been developed for controlling the rod motion such that the beam focal point scans a horizontal spiral and the subsequent heating zone is cylindrical. In coordination with this effort, a 3D finite element thermal model has been developed to evaluate the temperature distributions from the scanned focused heating. In this way, scanning protocols can be optimized to deliver the most uniform temperature rise to the desired location.

3-D Ultrafast Doppler Imaging Applied to the Noninvasive and Quantitative Imaging of Blood Vessels in Vivo

PubMed Central

Provost, J.; Papadacci, C.; Demene, C.; Gennisson, J-L.; Tanter, M.; Pernot, M.

2016-01-01

Ultrafast Doppler Imaging was introduced as a technique to quantify blood flow in an entire 2-D field of view, expanding the field of application of ultrasound imaging to the highly sensitive anatomical and functional mapping of blood vessels. We have recently developed 3-D Ultrafast Ultrasound Imaging, a technique that can produce thousands of ultrasound volumes per second, based on three-dimensional plane and diverging wave emissions, and demonstrated its clinical feasibility in human subjects in vivo. In this study, we show that non-invasive 3-D Ultrafast Power Doppler, Pulsed Doppler, and Color Doppler Imaging can be used to perform quantitative imaging of blood vessels in humans when using coherent compounding of three-dimensional tilted plane waves. A customized, programmable, 1024-channel ultrasound system was designed to perform 3-D Ultrafast Imaging. Using a 32X32, 3-MHz matrix phased array (Vermon, France), volumes were beamformed by coherently compounding successive tilted plane wave emissions. Doppler processing was then applied in a voxel-wise fashion. 3-D Ultrafast Power Doppler Imaging was first validated by imaging Tygon tubes of varying diameter and its in vivo feasibility was demonstrated by imaging small vessels in the human thyroid. Simultaneous 3-D Color and Pulsed Doppler Imaging using compounded emissions were also applied in the carotid artery and the jugular vein in one healthy volunteer. PMID:26276956

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

PubMed

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

2017-09-21

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 need 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.

Refixation of Osteochondral Fractures by an Ultrasound-Activated Pin System – An Ovine In Vivo Examination Using CT and Scanning Electron Microscope

PubMed Central

H, Neumann; A.P, Schulz; S, Breer; A, Unger; B, Kienast

2015-01-01

Background: Osteochondral injuries, if not treated appropriately, often lead to severe osteoarthritis of the affected joint. Without refixation of the osteochondral fragment, human cartilage only repairs these defects imperfectly. All existing refixation systems for chondral defects have disadvantages, for instance bad MRI quality in the postoperative follow-up or low anchoring forces. To address the problem of reduced stability in resorbable implants, ultrasound-activated pins were developed. By ultrasound-activated melting of the tip of these implants a higher anchoring is assumed. Aim of the study was to investigate, if ultrasound-activated pins can provide a secure refixation of osteochondral fractures comparing to conventional screw and conventional, resorbable pin osteosynthesis. CT scans and scanning electron microscopy should proovegood refixation results with no further tissue damage by the melting of the ultrasound-activated pins in comparison to conventional osteosynthesis. Methods: Femoral osteochondral fragments in sheep were refixated with ultrasound-activated pins (SonicPin™), Ethipins® and screws (Asnis™). The quality of the refixated fragments was examined after three month of full weight bearing by CT scans and scanning electron microscopy of the cartilage surface. Results: The CT examination found almost no statistically significant difference in the quality of refixation between the three different implants used. Concerning the CT morphology, ultrasound-activated pins demonstrated at least the same quality in refixation of osteochondral fragments as conventional resorbable pins or screws. The scanning electron microscopy showed no major surface damage by the three implants, especially any postulated cartilage damage induced by the heat of the ultrasound-activated pin. The screws protruded above the cartilage surface, which may affect the opposingtibial surface. Conclusion: Using CT scans and scanning electron microscopy, the Sonic

Visualizing ultrasound through computational modeling

NASA Technical Reports Server (NTRS)

Guo, Theresa W.

2004-01-01

The Doppler Ultrasound Hematocrit Project (DHP) hopes to find non-invasive methods of determining a person s blood characteristics. Because of the limits of microgravity and the space travel environment, it is important to find non-invasive methods of evaluating the health of persons in space. Presently, there is no well developed method of determining blood composition non-invasively. This projects hopes to use ultrasound and Doppler signals to evaluate the characteristic of hematocrit, the percentage by volume of red blood cells within whole blood. These non-invasive techniques may also be developed to be used on earth for trauma patients where invasive measure might be detrimental. Computational modeling is a useful tool for collecting preliminary information and predictions for the laboratory research. We hope to find and develop a computer program that will be able to simulate the ultrasound signals the project will work with. Simulated models of test conditions will more easily show what might be expected from laboratory results thus help the research group make informed decisions before and during experimentation. There are several existing Matlab based computer programs available, designed to interpret and simulate ultrasound signals. These programs will be evaluated to find which is best suited for the project needs. The criteria of evaluation that will be used are 1) the program must be able to specify transducer properties and specify transmitting and receiving signals, 2) the program must be able to simulate ultrasound signals through different attenuating mediums, 3) the program must be able to process moving targets in order to simulate the Doppler effects that are associated with blood flow, 4) the program should be user friendly and adaptable to various models. After a computer program is chosen, two simulation models will be constructed. These models will simulate and interpret an RF data signal and a Doppler signal.

Arterial and Venous Doppler in Evaluation of the "At-Risk" Fetus.

PubMed

Turan, Sifa; Turan, Ozhan M

2017-09-01

Our practice utilizes Doppler ultrasound as one of the most objective and effective methods to assess at-risk pregnancies. This review will discuss the application of arterial and venous Doppler techniques in assessing and managing various diseases and conditions for high-risk fetuses.

Ultrasound in the evaluation of enthesitis: status and perspectives.

PubMed

Gandjbakhch, Frédérique; Terslev, Lene; Joshua, Fredrick; Wakefield, Richard J; Naredo, Esperanza; D'Agostino, Maria Antonietta

2011-01-01

An increasing number of studies have applied ultrasound to the evaluation of entheses in spondyloarthritis patients. However, no clear agreement exists on the definition of enthesitis, on the number and choice of entheses to examine and on ultrasound technique, which may all affect the results of the examination. The objectives of this study were to first determine the level of homogeneity in the ultrasound definitions for the principal lesions of enthesitis in the published literature and second, to evaluate the metric properties of ultrasound for detecting enthesitis according to the OMERACT filter. Search was performed in PUBMED and EMBASE. Both grey-scale and Doppler definitions of enthesitis, including describing features of enthesitis, were collected and metrological qualities of studies were assessed. After selection, 48 articles were analyzed. The definition of ultrasound enthesitis and elementary features varied among authors. Grey-scale enthesitis was characterized by increasing thickness (94% of studies), hypoechogenicity (83%), enthesophytes (69%), erosions (67%), calcifications (52%), associated bursitis (46%) and cortical irregularities (29%). Only 46% of studies reported the use of Doppler. High discrepancies were observed on frequency, type of probe and Doppler mode used. Face and content validity were the most frequently evaluated criteria (43%) followed by reliability (29%) and responsiveness (19%). Ultrasound has evidence to support face, content validity and reliability for the evaluation of enthesitis, though there is a lack of well-reported methodology in most of the studies. Consensus on elementary lesions and standardization of exam is needed to determine the ultrasound definition of enthesitis in grey-scale and in Doppler for future applications.

Virtual Guidance Ultrasound: A Tool to Obtain Diagnostic Ultrasound for Remote Environments

NASA Technical Reports Server (NTRS)

Caine,Timothy L.; Martin David S.; Matz, Timothy; Lee, Stuart M. C.; Stenger, Michael B.; Platts, Steven H.

2012-01-01

Astronauts currently acquire ultrasound images on the International Space Station with the assistance of real-time remote guidance from an ultrasound expert in Mission Control. Remote guidance will not be feasible when significant communication delays exist during exploration missions beyond low-Earth orbit. For example, there may be as much as a 20- minute delay in communications between the Earth and Mars. Virtual-guidance, a pre-recorded audio-visual tutorial viewed in real-time, is a viable modality for minimally trained scanners to obtain diagnostically-adequate images of clinically relevant anatomical structures in an autonomous manner. METHODS: Inexperienced ultrasound operators were recruited to perform carotid artery (n = 10) and ophthalmic (n = 9) ultrasound examinations using virtual guidance as their only instructional tool. In the carotid group, each each untrained operator acquired two-dimensional, pulsed, and color Doppler of the carotid artery. In the ophthalmic group, operators acquired representative images of the anterior chamber of the eye, retina, optic nerve, and nerve sheath. Ultrasound image quality was evaluated by independent imaging experts. RESULTS: Eight of the 10 carotid studies were judged to be diagnostically adequate. With one exception the quality of all the ophthalmic images were adequate to excellent. CONCLUSION: Diagnostically-adequate carotid and ophthalmic ultrasound examinations can be obtained by untrained operators with instruction only from an audio/video tutorial viewed in real time while scanning. This form of quick-response-guidance, can be developed for other ultrasound examinations, represents an opportunity to acquire important medical and scientific information for NASA flight surgeons and researchers when trained medical personnel are not present. Further, virtual guidance will allow untrained personnel to autonomously obtain important medical information in remote locations on Earth where communication is

Multiparametric ultrasound in the detection of prostate cancer: a systematic review.

PubMed

Postema, Arnoud; Mischi, Massimo; de la Rosette, Jean; Wijkstra, Hessel

2015-11-01

To investigate the advances and clinical results of the different ultrasound modalities and the progress in combining them into multiparametric UltraSound (mpUS). A systematic literature search on mpUS and the different ultrasound modalities included: greyscale ultrasound, computerized transrectal ultrasound, Doppler and power Doppler techniques, dynamic contrast-enhanced ultrasound and (shear wave) elastography. Limited research available on combining ultrasound modalities has presented improvement in diagnostic performance. The data of two studies suggest that even adding a lower performing ultrasound modality to a better performing modality using crude methods can already improve the sensitivity by 13-51 %. The different modalities detect different tumours. No study has tried to combine ultrasound modalities employing a system similar to the PIRADS system used for mpMRI or more advanced classifying algorithms. Available evidence confirms that combining different ultrasound modalities significantly improves diagnostic performance.

Clinical use of ultrasonography associated with color Doppler in the diagnosis and follow-up of acute pyelonephritis.

PubMed

Dell'Atti, Lucio; Borea, Pier Andrea; Ughi, Gianni; Russo, Gian Rosario

2010-12-01

The purpose of this study is to evaluate the current role of the Ultrasound associated with the color-Doppler in the diagnosis of acute pyelonephritis (APN) and to compare ultrasound images with CT images in order to reduce the amount radiation absorbe without significant loss of diagnostic efficacy, since this disease in most cases affects young adults. We studied 38 patients (aged 17-65 years) who presented from September 2007 to March 2010 to the emergency department with suspected diagnosis of APN. All patients underwent first to an ultrasound study, then to abdominal CT. Renal, perirenal and extrarenal tomographic findings usually associated with acute pyelonephritis were analyzed, in an attempt to identify what are the differences with respect to the images obtained with an ultrasound study. All patients then performed ultrasonography and/or abdominal CT evaluation one month later, 25 patients repeated both examinations, while the other 13 repeated only ultrasound. In 38 subjects with suspected APN, CT assessed the presence in 79% and in 21% the absence of the disease. Ultrasonography in 68% of cases diagnosed APN, by an increase in kidney size related to the presence of hypoechoic areas associated to edema, blurred margins and reduction of the color-Doppler vascularity. Ultrasound associated with the use of color-Doppler revealed a sensibility of 76% and specificity of 75%. Color and power-Doppler have better diagnostic accuracy than basic gray scale ultrasound, in the diagnosis of focal pyelonephritis. Therefore the combined use of ultrasound and color-Doppler can obtain useful information about the diagnosis and follow-up of the disease, with an improvement in terms of cost, without significantly altering the diagnostic efficacy and reducing the amount of radiation absorbed.

In-Suit Doppler Technology Assessment

NASA Technical Reports Server (NTRS)

Schulze, Arthur E.; Greene, Ernest R.; Nadeau, John J.

1991-01-01

The objective of this program was to perform a technology assessment survey of non-invasive air embolism detection utilizing Doppler ultrasound methodologies. The primary application of this technology will be a continuous monitor for astronauts while performing extravehicular activities (EVA's). The technology assessment was to include: (1) development of a full understanding of all relevant background research; and (2) a survey of the medical ultrasound marketplace for expertise, information, and technical capability relevant to this development. Upon completion of the assessment, LSR was to provide an overview of technological approaches and R&D/manufacturing organizations.

Evaluating the intra- and interobserver reliability of three-dimensional ultrasound and power Doppler angiography (3D-PDA) for assessment of placental volume and vascularity in the second trimester of pregnancy.

PubMed

Jones, Nia W; Raine-Fenning, Nick J; Mousa, Hatem A; Bradley, Eileen; Bugg, George J

2011-03-01

Three-dimensional (3-D) power Doppler angiography (3-D-PDA) allows visualisation of Doppler signals within the placenta and their quantification is possible by the generation of vascular indices by the 4-D View software programme. This study aimed to investigate intra- and interobserver reproducibility of 3-D-PDA analysis of stored datasets at varying gestations with the ultimate goal being to develop a tool for predicting placental dysfunction. Women with an uncomplicated, viable singleton pregnancy were scanned at 12, 16 or 20 weeks gestational age groups. 3-D-PDA datasets acquired of the whole placenta were analysed using the VOCAL software processing tool. Each volume was analysed by three observers twice in the A plane. Intra- and interobserver reliability was assessed by intraclass correlation coefficients (ICCs) and Bland Altman plots. At each gestational age group, 20 low risk women were scanned resulting in 60 datasets in total. The ICC demonstrated a high level of measurement reliability at each gestation with intraobserver values >0.90 and interobserver values of >0.6 for the vascular indices. Bland Altman plots also showed high levels of agreement. Systematic bias was seen at 20 weeks in the vascular indices obtained by different observers. This study demonstrates that 3-D-PDA data can be measured reliably by different observers from stored datasets up to 18 weeks gestation. Measurements become less reliable as gestation advances with bias between observers evident at 20 weeks. Copyright © 2011 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

[Vascular complications following kidney transplant: the role of color-Doppler imaging].

PubMed

Granata, Antonio; Floccari, Fulvio; Lentini, Paolo; Vittoria, Salvatore; Di Pietro, Fabio; Zamboli, Pasquale; Fiorini, Fulvio; Fatuzzo, Pasquale

2012-01-01

The progressive decline in the incidence of graft rejection has made urological, surgical, parenchymal and vascular complications of kidney transplant more frequent. The latter, although accounting for only 5-10% of all post-transplant complications, are a frequent cause of graft loss. 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 parenchymal and surgical complications of the transplanted kidney, its role is not fully understood in case of vascular complications of the graft. The specificity of Doppler ultrasound is very important in case of stenosis of the transplanted renal artery, pseudoaneurysms, arteriovenous fistulas, and thrombosis with complete or partial artery or vein occlusion. Doppler and color determinations present high diagnostic accuracy, which is higher in case of successive measurements performed during the follow-up of the graft. Modern techniques including contrast-enhanced ultrasound increase the diagnostic power of ultrasonography in case of vascular complications of the transplanted kidney, planted kidney.

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. Copyright © 2013 Elsevier B.V. All rights reserved.

A new method for blood velocity measurements using ultrasound FMCW signals.

PubMed

Kunita, Masanori; Sudo, Masamitsu; Inoue, Shinya; Akahane, Mutsuhiro

2010-05-01

The low peak power of frequency-modulated continuous wave (FMCW) radar makes it attractive for various applications, including vehicle collision warning systems and airborne radio altimeters. This paper describes a new ultrasound Doppler measurement system that measures blood flow velocity based on principles similar to those of FMCW radar. We propose a sinusoidal wave for FM modulation and introduce a new demodulation technique for obtaining Doppler information with high SNR and range resolution. Doppler signals are demodulated with a reference FMCW signal to adjust delay times so that they are equal to propagation times between the transmitter and the receiver. Analytical results suggest that Doppler signals can be obtained from a selected position, as with a sample volume in pulse wave Doppler systems, and that the resulting SNR is nearly identical to that obtained with continuous wave (CW) Doppler systems. Additionally, clutter power is less than that of CW Doppler systems. The analytical results were verified by experiments involving electronic circuits and Doppler ultrasound phantoms.

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.

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

Factors affecting feasibility and quality of second-trimester ultrasound scans in obese pregnant women.

PubMed

Fuchs, F; Houllier, M; Voulgaropoulos, A; Levaillant, J-M; Colmant, C; Bouyer, J; Senat, M-V

2013-01-01

To evaluate the feasibility of completing in one session a second-trimester ultrasound scan in obese pregnant women, to compare the quality of images obtained with those of non-obese women and to analyze factors that can improve the completion rate. This prospective study, from 2009 to 2011, included all obese pregnant women (prepregnancy body mass index (BMI) > 30 kg/m2) who had an ultrasound examination at 20-24 weeks in our department, and a control group of pregnant women with normal BMI (20-24.9 kg/m2) who had the same examination. A single operator reviewed the standardized ultrasound images (three biometric and six to assess key anatomical features) required under French guidelines, to assess their presence, evaluate the quality of all images and score the quality of the six anatomical images. Each image was assessed according to between four and six criteria, each worth one point. We sought excellent quality, defined as the frequency of maximum points for a given image type. The factors associated with completing the scan in one session were evaluated with multivariate logistic regression. The obese group included 223 women and the control group 60; a complete scan in one session was achieved in 70.4% and 81.7% of these, respectively (P = 0.08). The completion rate for each image type was at least 95% in the control group and 90% in the obese group, except for diaphragm and right outflow tract images. Significant factors associated with completing the scan in the multivariate model were: having 10 additional minutes for the scan (P = 0.03), moving the fetus so that the back was in posterior or lateral position (P = 0.01), more experienced sonographer (P = 0.03) and thinner maternal abdominal wall thickness (P = 0.01). Overall, the excellence rate varied from 35% to 92% in the normal BMI group and from 18% to 58% in the obese group, and was significantly lower in the latter for all images except abdominal circumference (P�

A New Active Cavitation Mapping Technique for Pulsed HIFU Applications – Bubble Doppler

PubMed Central

Li, Tong; Khokhlova, Tatiana; Sapozhnikov, Oleg; Hwang, Joo Ha; Sapozhnikov, Oleg; O’Donnell, Matthew

2015-01-01

In this work, a new active cavitation mapping technique for pulsed high-intensity focused ultrasound (pHIFU) applications termed bubble Doppler is proposed and its feasibility tested in tissue-mimicking gel phantoms. pHIFU therapy uses short pulses, delivered at low pulse repetition frequency, to cause transient bubble activity that has been shown to enhance drug and gene delivery to tissues. The current gold standard for detecting and monitoring cavitation activity during pHIFU treatments is passive cavitation detection (PCD), which provides minimal information on the spatial distribution of the bubbles. B-mode imaging can detect hyperecho formation, but has very limited sensitivity, especially to small, transient microbubbles. The bubble Doppler method proposed here is based on a fusion of the adaptations of three Doppler techniques that had been previously developed for imaging of ultrasound contrast agents – color Doppler, pulse inversion Doppler, and decorrelation Doppler. Doppler ensemble pulses were interleaved with therapeutic pHIFU pulses using three different pulse sequences and standard Doppler processing was applied to the received echoes. The information yielded by each of the techniques on the distribution and characteristics of pHIFU-induced cavitation bubbles was evaluated separately, and found to be complementary. The unified approach - bubble Doppler – was then proposed to both spatially map the presence of transient bubbles and to estimate their sizes and the degree of nonlinearity. PMID:25265178

Ultrasound diagnosis and management of acquired uterine enhanced myometrial vascularity/arteriovenous malformations.

PubMed

Timor-Tritsch, Ilan E; Haynes, Meagan Campol; Monteagudo, Ana; Khatib, Nizar; Kovács, Sándor

2016-06-01

Arteriovenous malformation is a short circuit between an organ's arterial and venous circulation. Arteriovenous malformations are classified as congenital and acquired. In the uterus, they may appear after curettage, cesarean delivery, and myomectomy among others. Their clinical feature is usually vaginal bleeding, which may be severe, if curettage is performed in unrecognized cases. Sonographically on 2-dimensional grayscale ultrasound scanning, the pathologic evidence appears as irregular, anechoic, tortuous, tubular structures that show evidence of increased vascularity when color Doppler is applied. Most of the time they resolve spontaneously; however, if left untreated, they may require involved treatments such as uterine artery embolization or hysterectomy. In the past, uterine artery angiography was the gold standard for the diagnosis; however, ultrasound scanning has diagnosed successfully and helped in the clinical management. Recently, arteriovenous malformations have been referred to as enhanced myometrial vascularities. The purpose of this study was to evaluate the role of transvaginal ultrasound scanning in the diagnosis and treatment of acquired enhanced myometrial vascularity/arteriovenous malformations to outline the natural history of conservatively followed vs treated lesions. This was a retrospective study to assess the presentation, treatment, and clinical pictures of patients with uterine Enhanced myometrial vascularity/arteriovenous malformations that were diagnosed with transvaginal ultrasound scanning. We reviewed both (1) ultrasound data (images, measured dimensions, and Doppler blood flow that were defined by its peak systolic velocity and (2) clinical data (age, reproductive status, clinical presentation, inciting event or procedure, surgical history, clinical course, time intervals that included detection to resolution or detection to treatment, and treatment rendered). The diagnostic criteria were "subjective" with a rich vascular

Investigation into the quantitative and qualitative characteristics of choroidal melanoma through magnetic resonance imaging and B-scan ultrasound

PubMed Central

Papayiannis, Vassilis; Tsaousis, Konstantinos T; Kouskouras, Constantinos A; Haritanti, Afroditi; Diakonis, Vasilios F; Tsinopoulos, Ioannis T

2017-01-01

Objective To investigate the homogeneity and vascularity of choroidal melanoma through magnetic resonance imaging (MRI) and brightness modulation (B-mode) ultrasound scan and their correlation with dimensions of tumor, as well as to measure the sensitivity of both modalities in retinal detachment (RD) detection. Materials and methods This retrospective chart review included patients diagnosed with choroidal melanoma. All these patients underwent MRI scans using T2-weighted (T2-WI) and T1-weighted (T1-WI) sequences, before and after an intravenous injection of paramagnetic contrast material. The patients were also examined using a B-mode ultrasound scan, and the results from both modalities were compared (tumor homogeneity, tumor height, tumor base diameter, and tumor vascularity). Results Forty-two patients (mean age=65.33±12.51 years) with choroidal melanoma were included in the study. Homogeneity was confirmed in 16 patients through ultrasound scan, in 19 patients through T1-WI sequence, in 21 patients through T2-WI sequence, and in 25 patients through T1-WI sequence + contrast (gadolinium). Patients with homogenous tumors presented with lower (P=0.0045) mean height than that of those with nonhomogenous tumors, whereas no statistically significant difference was found for base diameter measurements (P=0.056). Patients with tumors of high vascularity presented with greater mean height (P=0.000638) and greater mean base diameter compared with those with tumors of low vascularity (P=0.019543). RD was detected in 26 patients through T1-WI sequence, in 13 patients through T2-WI sequence, in 26 patients through T1-WI sequence + contrast, and in 32 patients through ultrasound scan, which proved to be the most sensitive modality. Conclusion The height of choroidal melanoma was positively correlated with tumor’s homogeneity. Melanomas of greater height were found to be less homogenous, due to increased degeneration and higher occurrence of intratumoral hemorrhage. In

Bone surface enhancement in ultrasound images using a new Doppler-based acquisition/processing method.

PubMed

Yang, Xu; Tang, Songyuan; Tasciotti, Ennio; Righetti, Raffaella

2018-01-17

Ultrasound (US) imaging has long been considered as a potential aid in orthopedic surgeries. US technologies are safe, portable and do not use radiations. This would make them a desirable tool for real-time assessment of fractures and to monitor fracture healing. However, image quality of US imaging methods in bone applications is limited by speckle, attenuation, shadow, multiple reflections and other imaging artifacts. While bone surfaces typically appear in US images as somewhat 'brighter' than soft tissue, they are often not easily distinguishable from the surrounding tissue. Therefore, US imaging methods aimed at segmenting bone surfaces need enhancement in image contrast prior to segmentation to improve the quality of the detected bone surface. In this paper, we present a novel acquisition/processing technique for bone surface enhancement in US images. Inspired by elastography and Doppler imaging methods, this technique takes advantage of the difference between the mechanical and acoustic properties of bones and those of soft tissues to make the bone surface more easily distinguishable in US images. The objective of this technique is to facilitate US-based bone segmentation methods and improve the accuracy of their outcomes. The newly proposed technique is tested both in in vitro and in vivo experiments. The results of these preliminary experiments suggest that the use of the proposed technique has the potential to significantly enhance the detectability of bone surfaces in noisy ultrasound images.

Bone surface enhancement in ultrasound images using a new Doppler-based acquisition/processing method

NASA Astrophysics Data System (ADS)

Yang, Xu; Tang, Songyuan; Tasciotti, Ennio; Righetti, Raffaella

2018-01-01

Ultrasound (US) imaging has long been considered as a potential aid in orthopedic surgeries. US technologies are safe, portable and do not use radiations. This would make them a desirable tool for real-time assessment of fractures and to monitor fracture healing. However, image quality of US imaging methods in bone applications is limited by speckle, attenuation, shadow, multiple reflections and other imaging artifacts. While bone surfaces typically appear in US images as somewhat ‘brighter’ than soft tissue, they are often not easily distinguishable from the surrounding tissue. Therefore, US imaging methods aimed at segmenting bone surfaces need enhancement in image contrast prior to segmentation to improve the quality of the detected bone surface. In this paper, we present a novel acquisition/processing technique for bone surface enhancement in US images. Inspired by elastography and Doppler imaging methods, this technique takes advantage of the difference between the mechanical and acoustic properties of bones and those of soft tissues to make the bone surface more easily distinguishable in US images. The objective of this technique is to facilitate US-based bone segmentation methods and improve the accuracy of their outcomes. The newly proposed technique is tested both in in vitro and in vivo experiments. The results of these preliminary experiments suggest that the use of the proposed technique has the potential to significantly enhance the detectability of bone surfaces in noisy ultrasound images.

Physics and instrumentation of ultrasound.

PubMed

Lawrence, John P

2007-08-01

A thorough understanding of the physics of ultrasound waves and the instrumentation will provide the user with a better understanding of the capabilities and limitations of ultrasound equipment. The ultrasound machine combines two technologies: image production (M-mode and 2-dimensional imaging) with Doppler assessment (continuous and pulse wave as well as color-flow mapping). These distinct technologies have been combined to provide the examiner with the ability to make accurate and comprehensive diagnoses and guide therapeutic intervention.

Ultrasound contrast agents: an overview.

PubMed

Cosgrove, David

2006-12-01

With the introduction of microbubble contrast agents, diagnostic ultrasound has entered a new era that allows the dynamic detection of tissue flow of both the macro and microvasculature. Underpinning this development is the fact that gases are compressible, and thus the microbubbles expand and contract in the alternating pressure waves of the ultrasound beam, while tissue is almost incompressible. Special software using multiple pulse sequences separates these signals from those of tissue and displays them as an overlay or on a split screen. This can be done at low acoustic pressures (MI<0.3) so that the microbubbles are not destroyed and scanning can continue in real time. The clinical roles of contrast enhanced ultrasound scanning are expanding rapidly. They are established in echocardiography to improve endocardial border detection and are being developed for myocardial perfusion. In radiology, the most important application is the liver, especially for focal disease. The approach parallels that of dynamic CT or MRI but ultrasound has the advantages of high spatial and temporal resolution. Thus, small lesions that can be indeterminate on CT can often be studied with ultrasound, and situations where the flow is very rapid (e.g., focal nodular hyperplasia where the first few seconds of arterial perfusion may be critical to making the diagnosis) are readily studied. Microbubbles linger in the extensive sinusoidal space of normal liver for several minutes whereas they wash out rapidly from metastases, which have a low vascular volume and thus appear as filling defects. The method has been shown to be as sensitive as three-phase CT. Microbubbles have clinical uses in many other applications where knowledge of the microcirculation is important (the macrocirculation can usually be assessed adequately using conventional Doppler though there are a few important situations where the signal boost given by microbubbles is useful, e.g., transcranial Doppler for evaluating

Current Perspectives in Hyperbaric Physiology, Ultrasonic Doppler Bubble Detection, and Mass Spectrometry,

DTIC Science & Technology

1979-12-28

Doppler sound made by a bubble passing through the inson- ified volume blood vessel resembles a very sharp truncated whistle , chirp or click depending...the Doppler ultrasound , suffered the "slings and arrows of outrageous criticism" to borrow and beat a phrase. It is not appropriate to go into this

Risk of deep venous thrombosis in elective neurosurgical procedures: a prospective, Doppler ultrasound-based study in children 12 years of age or younger.

PubMed

Scherer, Andrea G; White, Ian K; Shaikh, Kashif A; Smith, Jodi L; Ackerman, Laurie L; Fulkerson, Daniel H

2017-07-01

OBJECTIVE The risk of venous thromboembolism (VTE) from deep venous thrombosis (DVT) is significant in neurosurgical patients. VTE is considered a leading cause of preventable hospital deaths and preventing DVT is a closely monitored quality metric, often tied to accreditation, hospital ratings, and reimbursement. Adult protocols include prophylaxis with anticoagulant medications. Children's hospitals may adopt adult protocols, although the incidence of DVT and the risk or efficacy of treatment is not well defined. The incidence of DVT in children is likely less than in adults, although there is very little prospectively collected information. Most consider the risk of DVT to be extremely low in children 12 years of age or younger. However, this consideration is based on tradition and retrospective reviews of trauma databases. In this study, the authors prospectively evaluated pediatric patients undergoing a variety of elective neurosurgical procedures and performed Doppler ultrasound studies before and after surgery. METHODS A total of 100 patients were prospectively enrolled in this study. All of the patients were between the ages of 1 month and 12 years and were undergoing elective neurosurgical procedures. The 91 patients who completed the protocol received a bilateral lower-extremity Doppler ultrasound examination within 48 hours prior to surgery. Patients did not receive either medical or mechanical DVT prophylaxis during or after surgery. The ultrasound examination was repeated within 72 hours after surgery. An independent, board-certified radiologist evaluated all sonograms. We prospectively collected data, including potential risk factors, details of surgery, and details of the clinical course. All patients were followed clinically for at least 1 year. RESULTS There was no clinical or ultrasound evidence of DVT or VTE in any of the 91 patients. There was no clinical evidence of VTE in the 9 patients who did not complete the protocol. CONCLUSIONS In this

Doppler ultrasound of the maternal uterine arteries: disappearance of abnormal waveforms and relation to birthweight and pregnancy outcome.

PubMed

Campbell, S; Black, R S; Lees, C C; Armstrong, V; Peacock, J L

2000-08-01

To assess whether the gestation at which abnormal uterine artery waveforms disappear is related to birthweight and complications of pregnancy. A prospective study of outcome of pregnancy after a uterine artery Doppler screening program set in an inner city teaching hospital. One thousand five hundred and twenty-four consecutive women attending the Obstetric Department for a routine anomaly scan at between 19 and 21 weeks gestation had maternal uterine arteries assessed using color wave Doppler. Those women in whom the flow was deemed abnormal were recalled for a further scan at 24-26 weeks gestation. The main outcome measures were birthweight, gestation at delivery and incidence of pre eclampsia. The women in whom the uterine artery blood flow was normal at 20 weeks had babies with significantly higher mean birthweight than those who normalized between 20 and 24-26 weeks gestation ('late normalizers') after adjustment for confounding factors; gestational age, maternal height, parity, ethnic group and smoking (mean difference=173 g, 95% confidence intervals 42 to 303 g). The timing of trophoblast invasion, as reflected by abnormal uterine artery waveforms, may have an effect on birthweight.

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.

Power Doppler ultrasound of rheumatoid synovitis: quantification of vascular signal and analysis of interobserver variability.

PubMed

Kamishima, Tamotsu; Tanimura, Kazuhide; Henmi, Mihoko; Narita, Akihiro; Sakamoto, Fumihiko; Terae, Satoshi; Shirato, Hiroki

2009-05-01

The objective of this study was to assess interobserver uncertainties in power Doppler (PD) examination of the fingers of patients with rheumatoid arthritis (RA), by separating the source of the discrepancy into (1) acquisition of the images and (2) criteria for assessment of the images. Twenty patients who had been diagnosed with RA were enrolled in this study. Ultrasound examinations were performed by one inexperienced and two experienced sonographers. Interobserver variation was measured using a conventional semiquantitative image grading scale. Interobserver variation of the quantitative PD (QPD) index (the summation of the colored pixels in a region of interest) was also assessed. The agreement was higher between the two experienced sonographers (kappa value of 0.8) than between experienced and inexperienced sonographers (kappa value, 0.6-0.7) in the semiquantitative image grading scale. Results suggest that the difference in the assessment on the image grading scale was due more to the difference in the acquisition of the images than to variations in the grading criteria between sonographers. An excellent relationship was noted between the image grading scale and the QPD index for Doppler signal with a Spearman's coefficient of rank correlation of 0.83 (P < 0.0001). Interobserver discrepancies in the image grading and QPD index methods were due more to the difference in the acquisition of the image than to the grading criteria used. The QPD index seems to be as reliable as the image grading scale with reasonable interobserver agreement between experienced sonographers.

Standards of the Polish Ultrasound Society - update. Ultrasound examination of the kidneys, ureters and urinary bladder.

PubMed

Tyloch, Janusz F; Woźniak, Magdalena Maria; Wieczorek, Andrzej Paweł

2013-09-01

The paper presents the principles of performing proper ultrasound examinations of the urinary tract. The following are discussed: preparation of patients, type of optimal apparatus, technique of examination and conditions which its description should fulfill. Urinary track examination in adults and in children constitutes an integral part of each abdominal examination. Such examinations should be performed with fasting patients or several hours after the last meal, with filled urinary bladder. Ultrasound examinations in children and infants are performed using transducers with the frequency of 5.0-9.0 MHz and in adults - with the frequency of 2.0-6.0 MHz. Doppler options are desirable since they improve diagnostic capacity of sonography in terms of differentiation between renal focal lesions. Renal examinations are performed with the patients in the supine position. The right kidney is examined in the right hypochondriac region using the liver as the ultrasound "window." The left kidney is examined in the left hypochondriac region, preferably in the posterior axillary line. Ultrasound examinations of the upper segment of the ureters are performed after renal examination when the pelvicalyceal system is dilated. A condition necessary for a proper examination of the perivesical portion of the ureter is full urinary bladder. The scans of the urinary bladder are performed in transverse, longitudinal and oblique planes when the bladder is filled. The description should include patient's personal details, details of the referring unit, of the unit in which the examination is performed, examining physician's details, type of ultrasound apparatus and transducers as well as the description proper.

The utility of ultrasound superb microvascular imaging for evaluation of breast tumour vascularity: comparison with colour and power Doppler imaging regarding diagnostic performance.

PubMed

Park, A Y; Seo, B K; Woo, O H; Jung, K S; Cho, K R; Park, E K; Cha, S H; Cha, J

2018-03-01

To investigate the utility of superb microvascular imaging (SMI) for evaluating the vascularity of breast masses in comparison with colour or power Doppler ultrasound (US) and the effect on diagnostic performance. A total of 191 biopsy-proven masses (99 benign and 92 malignant) in 166 women with greyscale, colour Doppler, power Doppler, and SMI images were enrolled in this retrospective study. Three radiologists analysed the vascular images using a three-factor scoring system to evaluate the number, morphology, and distribution of tumour vessels. They assessed the Breast Imaging-Reporting and Data System categories for greyscale US alone and combinations of greyscale US and each type of vascular US. The Kruskal-Wallis test was performed and the area under the receiver-operating characteristic curve (AUC) measured. On SMI, vascular scores were compared between benign and malignant masses and the optimal cut-off value for the overall score was determined. SMI showed higher vascular scores than colour or power Doppler US and malignant masses had higher scores than benign masses (p<0.001). The diagnostic performance of the combination of greyscale US and SMI was higher than those of greyscale US alone and greyscale and colour or power Doppler US (AUC, 0.815 versus 0.774, 0.789, 0.791; p<0.001). The optimal cut-off value of the overall vascular score was 5 with a sensitivity of 82.3% and a specificity of 65.3% (AUC, 0.808). SMI is superior to colour or power Doppler US for characterising the vascularity in breast masses and improving diagnostic performance. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

High-Frame-Rate Doppler Ultrasound Using a Repeated Transmit Sequence

PubMed Central

Podkowa, Anthony S.; Oelze, Michael L.; Ketterling, Jeffrey A.

2018-01-01

The maximum detectable velocity of high-frame-rate color flow Doppler ultrasound is limited by the imaging frame rate when using coherent compounding techniques. Traditionally, high quality ultrasonic images are produced at a high frame rate via coherent compounding of steered plane wave reconstructions. However, this compounding operation results in an effective downsampling of the slow-time signal, thereby artificially reducing the frame rate. To alleviate this effect, a new transmit sequence is introduced where each transmit angle is repeated in succession. This transmit sequence allows for direct comparison between low resolution, pre-compounded frames at a short time interval in ways that are resistent to sidelobe motion. Use of this transmit sequence increases the maximum detectable velocity by a scale factor of the transmit sequence length. The performance of this new transmit sequence was evaluated using a rotating cylindrical phantom and compared with traditional methods using a 15-MHz linear array transducer. Axial velocity estimates were recorded for a range of ±300 mm/s and compared to the known ground truth. Using these new techniques, the root mean square error was reduced from over 400 mm/s to below 50 mm/s in the high-velocity regime compared to traditional techniques. The standard deviation of the velocity estimate in the same velocity range was reduced from 250 mm/s to 30 mm/s. This result demonstrates the viability of the repeated transmit sequence methods in detecting and quantifying high-velocity flow. PMID:29910966

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.

Using the angiogenic factors sFlt-1 and PlGF with Doppler ultrasound of the uterine artery for confirming preeclampsia.

PubMed

Bahlmann, Franz; Al Naimi, Ammar

2016-11-01

The aim of this study is to assess the value of the angiogenic factors for diagnosing preeclampsia and predicting the severity of manifestation. A secondary aim is assessing the combination of the uterine artery Doppler with the angiogenic factors for improving the diagnostic power. This is a prospective single center study in a tertiary referral hospital. This study includes 728 individual patients. Inclusion criteria were singleton pregnancies, a referral to the hospital with suspicion of preeclampsia and any one or combination of the following symptoms: headache, upper abdominal pain, edema, and hypertension. Patients with complications that would affect the course of the pregnancy, such as placenta praevia, premature preterm rupture of membranes, breech presentation, and fetal chromosomal or structural anomalies, were excluded from the study. Blood samples collection and uterine artery Doppler ultrasound were performed at time of recruitment. The differences in sFlt-1, PlGF, and their quotient among normal collective and patients with preeclampsia were analyzed. Doppler ultrasound was performed by one of four highly qualified sonographers. Wilcoxon-Mann-Whitney U test, Spearman's rank correlation, receiver operating characteristic curves, Chi-square test, and logistic regression were used in the analysis. A total of 1003 individual samples for the angiogenic factors were included in the analysis. 584 out of the recruited 728 patients had follow-up data with delivery information at the study hospital. Patients with preeclampsia show a significant increase in sFlt-1, which directly correlate with the increased severity of manifestation (Spearman's ρ 0.49). The sFlt-1 cut-off value of 5424 pg/ml confirms preeclampsia with 83.7 % sensitivity, 68.1 % specificity, and 24 % misclassification rate. Preeclampsia patients also show a significant decrease in PlGF, which negatively correlates with the increased severity of manifestation (Spearman's ρ -0.39). A Pl

Musculoskeletal ultrasound and other imaging modalities in rheumatoid arthritis.

PubMed

Ohrndorf, Sarah; Werner, Stephanie G; Finzel, Stephanie; Backhaus, Marina

2013-05-01

This review refers to the use of musculoskeletal ultrasound in patients with rheumatoid arthritis (RA) both in clinical practice and research. Furthermore, other novel sensitive imaging modalities (high resolution peripheral quantitative computed tomography and fluorescence optical imaging) are introduced in this article. Recently published ultrasound studies presented power Doppler activity by ultrasound highly predictive for later radiographic erosions in patients with RA. Another study presented synovitis detected by ultrasound being predictive of subsequent structural radiographic destruction irrespective of the ultrasound modality (grayscale ultrasound/power Doppler ultrasound). Further studies are currently under way which prove ultrasound findings as imaging biomarkers in the destructive process of RA. Other introduced novel imaging modalities are in the validation process to prove their impact and significance in inflammatory joint diseases. The introduced imaging modalities show different sensitivities and specificities as well as strength and weakness belonging to the assessment of inflammation, differentiation of the involved structures and radiological progression. The review tries to give an answer regarding how to best integrate them into daily clinical practice with the aim to improve the diagnostic algorithms, the daily patient care and, furthermore, the disease's outcome.

Comparison of Two Devices for Intraoperative Portal Venous Flow Measurement in Living-Donor Liver Transplantation: Transit Time Ultrasound and Conventional Doppler Ultrasound.

PubMed

Wang, H-K; Chen, C-Y; Lin, N-C; Liu, C-S; Loong, C-C; Lin, Y-H; Lai, Y-C; Chiou, H-J

2018-05-01

Intraoperative portal venous flow measurement provides surgeons with instant guidance for portal flow modulation during living-donor liver transplantation (LDLT). In this study, we compared the agreement of portal flow measurement obtained by 2 devices: transit time ultrasound (TTU) and conventional Doppler ultrasound (CDU). Fifty-four recipients of LDLT underwent intraoperative measurement of portal flow after completion of vascular anastomosis of the implanted partial liver graft. Both TTU and CDU were used concurrently. Agreement of TTU and CDU was assessed by intraclass correlation coefficient using a model of 2-way random effects, absolute agreement, and single measurement. A Bland-Altman plot was applied to assess the variability between the 2 devices. The mean, median, and range of portal venous flow was 1456, 1418, and 117 to 2776 mL/min according to TTU; and 1564, 1566, and 119 to 3216 mL/min according to CDU. The intraclass correlation coefficient of portal venous flow between TTU and CDU was 0.68 (95% confidence interval, 0.51-0.80). The Bland-Altman plots revealed an average variation of 4.8% between TTU and CDU but with a rather wide 95% confidence interval of variation ranging from -57.7% to 67.4%. Intraoperative TTU and CDU showed moderate agreement in portal flow measurement. However, a relatively wide range of variation exists between TTU and CDU, indicating that data obtained from the 2 devices may not be interchangeable. Copyright © 2018 Elsevier Inc. All rights reserved.

Ultrasound diagnostic of mesonephric paraovarian cyst - case report

PubMed Central

Bohîlțea, RE; Cîrstoiu, MM; Turcan, N; Ionescu, CA

2016-01-01

Paraovarian cysts are a rare pathology, constituting 10-20% of the adnexal masses. The origin can be represented by paramesonephric ducts (Hydatid cysts of Morgagni), vestiges of mesonephric ducts also represented by mesothelium, or neoplastic (cystadenomas or cystadenofibromas) that are mostly benign. Borderline or malignant paraovarian tumors are encountered less often. This article presents a case of paraovarian cyst in a 37-year-old patient, with a history of 2 pregnancies, completed by cesarean. The patient sought medical attention for an asymptomatic voluminous ovarian cyst, detected in a routine ultrasound scan. Laboratory tests and tumor markers were within normal limits. Transvaginal ultrasound and color Doppler revealed a cystic adnexal mass with 10 cm transonic, smooth, homogeneous content, avascular walls with no internal papillary projections, with a “hyperechoic line” sign of delimitation from the ovarian capsule, mostly visible when the adnexa was mobilized. The diagnostic and curative laparoscopic surgery was successful, followed by a quick recovery. The histopathological exam confirmed the benignity and the origin of the paraovarian cyst. The case was discussed in the context of the literature review concerning this pathology, drawing attention to the real possibility of differentiating ovarian from paraovarian cysts by ultrasound. PMID:27974934

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.

[Ultrasound diagnosis of aneurysm of the vein of Galen in children].

PubMed

Gazikalović, S; Kosutić, J; Komar, P; Vukomanović, V; Mogić, M

2001-01-01

Aneurysm of the vein of Galen is rare and complex vascular disorder that develops during embriogenesis and provokes significant haemodynamic changes. Boys are more frequently involved. During the foetal period Ballantyne syndrome may develop, and postnatal clinical presentation vary with ages. Serious haemodynamic changes are followed by congestive heart failure and, if not treated, with lethal exitus. Fast and correct diagnosis is very important. Ultrasound examination of central nervous system supported with Duplex-Doppler and Colour-Doppler examination of the head and heart enables the diagnosis. This text comments ultrasound presentation of the malformation and ultrasound diagnostic possibilities.

Evaluation of contrast-enhanced power Doppler imaging for measuring blood flow

NASA Astrophysics Data System (ADS)

Ansaloni, Sara; Arger, Peter H.; Cary, Ted W.; Sehgal, Chandra M.

2005-04-01

Power Doppler ultrasound enhanced by microbubble contrast agent has been used to image tissue vascularity and blood flow for the assessment of antivascular therapies. We have proposed a multigating technique that measures bubble concentration as a function of ultrasound exposure for deriving tumor blood flow and vascularity.1 Techniques using ultrasound contrast agent are known to be sensitive to the choice of imaging parameters like mechanical index and tissue attenuation. In this paper, the roles of mechanical index (MI) and tissue attenuation were evaluated experimentally in a rubber tubing flow phantom connected to a mixing chamber and a variable speed pump. The contrast was injected in the mixing chamber and the flow rate was measured using power Doppler imaging. The measurements were repeated at different MIs (0.1 to 1.3), and at different levels of attenuation, obtained with solutions of glycerol-water (10-20%). True flow was measured by collecting liquid flowing out of the phantom over a fixed duration. At low MI (<0.5), the grayscale and Doppler signal were weak, making these images unsuitable for analysis. At higher MI (> 0.8), there was a well-defined enhancement by contrast agent resulting in reproducible flow measurements at variable MIs. A balance between the number of bubbles destroyed and the echo they generate must be achieved for optimal imaging. The increased attenuation of ultrasound by the overlying medium did not influence the flow measurements.

Abdominal ultrasound (image)

MedlinePlus

Abdominal ultrasound is a scanning technique used to image the interior of the abdomen. Like the X-ray, MRI, ... it has its place as a diagnostic tool. Ultrasound scans use high frequency sound waves to produce ...

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.

Ultrasound contrast agents for bleeding detection and acoustic hemostasis

NASA Astrophysics Data System (ADS)

Zderic, Vesna; Luo, Wenbo; Brayman, Andrew; Crum, Lawrence; Vaezy, Shahram

2005-04-01

Objective: To investigate the application of ultrasound contrast agents (UCA) in improving both therapeutic and diagnostic aspects of ultrasound-guided High Intensity Focused Ultrasound (HIFU) therapy. Methods: Incisions (3 cm long, 0.5 cm deep) were made in rabbit livers (in anterior surface for HIFU treatment, or posterior surface for bleeding detection). UCA Optison (~0.1 ml/kg) was injected into mesenteric vein or ear vein. A HIFU applicator (5.5 MHz, 6400 W/cm2) was scanned manually over the incision until hemostasis was achieved. Occult bleeding was monitored with Doppler ultrasound. Results: The presence of Optison produced 37% reduction in hemostasis times normalized to initial bleeding rates. Gross and histological observations showed similar appearance of HIFU lesions produced in the presence of Optison and control HIFU lesions. The temperature reached 100°C in both HIFU only and HIFU+UCA treatments. Tension strength of hemostatic liver incisions was 0.9+/-0.5 N. Almost no bleeding could be detected before Optison injection. First appearance of contrast enhancement localized at the bleeding site was 15 s after Optison injection, and lasted for ~50 s. Conclusion: The presence of UCA during HIFU treatment of liver incisions resulted in shortening of HIFU application times and better visualization of bleeding sites.

Associations between abnormal ultrasound color Doppler measures and tendon pain symptoms in badminton players during a season: a prospective cohort study.

PubMed

Boesen, Anders Ploug; Boesen, Morten Ilum; Torp-Pedersen, Soren; Christensen, Robin; Boesen, Lars; Hölmich, Per; Nielsen, Michael Bachmann; Koenig, Merete Juhl; Hartkopp, Andreas; Ellegaard, Karen; Bliddal, Henning; Langberg, Henning

2012-03-01

Color Doppler ultrasound is widely used to examine intratendinous flow in individuals with overuse tendon problems, but the association between color Doppler and pain is still unclear. Intratendinous flow is present and associated with pain in badminton players, and intratendinous flow and pain increase during a badminton season. Cohort study (prognosis); Level of evidence, 2. Ninety-five semiprofessional badminton players were included in the study at a tournament at the start of the badminton season. All players were interviewed regarding pain. The anterior knee tendons and Achilles tendons were studied. Each tendon was scored using a quantitative grading system (grades 0-5) and a qualitative scoring system (color fraction) using color Doppler ultrasound. Eight months later, 86 of the players (91%) were retested by the same investigators during an equivalent badminton tournament (including 1032 tendon regions; 86 players with 4 tendons each with 3 regions), thus forming the study group. At the start of the season, 24 players (28%) experienced pain in 37 tendons (11%), and at the end of the season, 31 players (36%) experienced pain in 51 tendons (15%), which was a statistically significant increase (P = .0002). Abnormal flow was found in 230 tendon regions in 71 players (83%) at the start of the season compared with 78 tendon regions in 41 players (48%) at the follow-up. The decrease in abnormal flow was statistically significant (P < .0001). Of the 37 painful tendons at the start of the season, 25 had abnormal flow (68%). In contrast, 131 tendons (85%) with abnormal flow at the start of the season were pain free. At the end of the season, 18 of the 51 painful tendons (35%) had abnormal flow. Ninety-six of the 131 pain-free tendons (73%) with abnormal flow at the start of the season were normalized (no pain and normal flow) at the end of the season. It was not possible to verify any association between intratendinous flow and pain at the start of the season or at

Laser Ultrasound Spectroscopy Scanning for 3D Printed Parts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brennan, Guendalyn Kendra

One of the challenges of additive manufacturing is quality control due to the possibility of unseen flaws in the final product. The current methods of inspection are lacking in detail, too slow for practical use, or unable to validate internal structure. This report examines the use of laser ultrasound spectroscopy in layer by layer scans of 3D printed parts as they are created. The result is fast and detailed quality control. An additional advantage of this method is the ability to cancel a print as soon as a defect is detected, therefore saving materials and time. This technique, though simplemore » in concept, has been a challenge to implement. I discuss tweaking the 3D printer configuration, and finding the optimal settings for laser scanning small parts made of ABS plastic, as well as the limits of how small of a detail the laser can detect. These settings include the frequency of the ultrasonic transducer, the speed of the laser, and the distance from the laser to the part.« less

Evaluation of gastrointestinal activity patterns in healthy horses using B mode and Doppler ultrasonography

PubMed Central

2005-01-01

Abstract Healthy adult horses were examined by using transabdominal ultrasonography to quantitatively and qualitatively evaluate activity of the jejunum, cecum, and colon with B mode and Doppler techniques. Doppler ultrasound was used to assess jejunal peristaltic activity. Examinations were performed on multiple occasions under imposed colic evaluation conditions, including fasting, nasogastric intubation, and xylazine sedation. In fasted horses, jejunal visibility was increased and jejunal, cecal, and colonic activity was decreased. The stomach was displaced ventrally and was visualized ventral to the costochondral junction. Xylazine sedation in fed horses had minimal effects; however, in fasted horses, xylazine significantly decreased jejunal and cecal activity. Nasogastric intubation in fasted horses had no observable effects on activity, but moved the stomach dorsally. B mode and Doppler jejunal activity were strongly correlated. Prior feeding and sedation status need to be considered when interpreting the results of equine abdominal ultrasound examinations. Doppler techniques may be useful for assessing jejunal activity. PMID:15825515

Monitoring the industrial sources of aerosol in Cubatao, Brazil, using a scanning elastic lidar and a lidar doppler

NASA Astrophysics Data System (ADS)

da Costa, Renata F.; Marques, Marcia T. A.; M Macedo, Fernanda de; Andrade, Izabel da Silva; Araujo, Elaine Cristina; Correa, Thais; de Andrade Salani, Maria Helena Goncalves; Lopes, Daniel Silveira; Goncalves Guardani, Maria Lucia; Landulfo, Eduardo; Guardani, Roberto

2018-04-01

Field campaigns with a scanning multiwavelength elastic lidar coupled with a Doppler system to monitor industrial atmospheric aerosol emissions were carried out, with the objective of monitoring aerosol emission sources and plume dispersion. Since the technique provides information on the spatial and temporal distribution of aerosol concentration, the implementation of a systematic monitoring procedure is proposed as a valuable tool in air quality monitoring applied to regions of interest.

Real-time clinically oriented array-based in vivo combined photoacoustic and power Doppler imaging

NASA Astrophysics Data System (ADS)

Harrison, Tyler; Jeffery, Dean; Wiebe, Edward; Zemp, Roger J.

2014-03-01

Photoacoustic imaging has great potential for identifying vascular regions for clinical imaging. In addition to assessing angiogenesis in cancers, there are many other disease processes that result in increased vascularity that present novel targets for photoacoustic imaging. Doppler imaging can provide good localization of large vessels, but poor imaging of small or low flow speed vessels and is susceptible to motion artifacts. Photoacoustic imaging can provide visualization of small vessels, but due to the filtering effects of ultrasound transducers, only shows the edges of large vessels. Thus, we have combined photoacoustic imaging with ultrasound power Doppler to provide contrast agent- free vascular imaging. We use a research-oriented ultrasound array system to provide interlaced ultrasound, Doppler, and photoacoustic imaging. This system features realtime display of all three modalities with adjustable persistence, rejection, and compression. For ease of use in a clinical setting, display of each mode can be disabled. We verify the ability of this system to identify vessels with varying flow speeds using receiver operating characteristic curves, and find that as flow speed falls, photoacoustic imaging becomes a much better method for identifying blood vessels. We also present several in vivo images of the thyroid and several synovial joints to assess the practicality of this imaging for clinical applications.

[Color Doppler ultrasonography--a new imaging procedure in maxillofacial surgery].

PubMed

Reinert, S; Lentrodt, J

1991-01-01

Colour Doppler ultrasonography shows blood flow in real time and colour by combining the features of real time B mode ultrasound and Doppler. At each point in the image the returning signal is interrogated for both amplitude and frequency information. The resulting image shows all non-moving structures in shades of gray and moving structures in shades of red or blue depending on direction and velocity. The technique of colour Doppler ultrasonography and our experiences in 63 examinations are described. The clinical application of this new simple non-invasive method in maxillo-facial surgery is discussed.

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

PubMed

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.

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

Diagnostic value of Doppler assessment of the hepatic and portal vessels and ultrasound of the spleen in liver disease.

PubMed

O'Donohue, John; Ng, Chaan; Catnach, Susan; Farrant, Patricia; Williams, Roger

2004-02-01

To investigate the clinical utility and the intra-observer and inter-observer variability of Doppler ultrasound assessment of the hepatic and portal vessels along with measurement of spleen size in the diagnosis of chronic liver disease and cirrhosis. Ultrasound measurements of portal vein diameter (PVD), portal vein velocity (PVV), hepatic arterial resistance index (HARI), hepatic vein profile (HVP), and spleen size were obtained in 49 controls and 45 patients with liver disease (23 with primary biliary cirrhosis, 22 with hepatitis C) by two experienced observers, who each performed three blinded measurements of each variable. Control values were derived from normal hospital workers. Percutaneous liver biopsies in 41 of the patients showed cirrhosis (14 patients), moderate/severe fibrosis (13 patients), and early disease (14 patients). Seventy-one percent of cirrhotic patients had splenomegaly (> 13.6 cm). The spleen size was significantly larger in cirrhotics (16.0 cm) than in non-cirrhotics (13.0 cm, P < 0.009) and healthy controls (10.7 cm, P < 0.00005), and was the only independent predictor of cirrhosis, with a threshold of 15 cm predicting cirrhosis with a specificity of 98%, positive predictive value of 93%, sensitivity of 57% and negative predictive value of 80%. HVP was abnormal in 76.9% of cirrhotics, 57.7% of non-cirrhotics and 2.1% of controls (P < 0.04). However, the mean PVV, PVD and HARI were no different between controls and patients or between cirrhotic and non-cirrhotic liver disease. There was significant inter-observer variability for PVV, but intra-observer and inter-observer variability was acceptable for the other measurements. Splenomegaly size and abnormal HVP are useful predictors of chronic liver disease and cirrhosis, and both can be measured reliably and reproducibly. However, Doppler measurements of PVV, PVD and HARI are not useful in distinguishing patients with chronic liver disease from normal controls.

The value of Doppler ultrasound in diagnosis in 25 cases of furunculoid myiasis.

PubMed

Quintanilla-Cedillo, Marco R; León-Ureña, Heberth; Contreras-Ruiz, José; Arenas, Roberto

2005-01-01

The larvae of the botfly Dermatobia hominis cause furunculoid myiasis in endemic areas. Lack of knowledge of this condition outside these areas leads to confusion in diagnosis and delays appropriate treatment. To describe the clinical findings of furunculoid myiasis encountered in Quintana Roo, in the south-east of Mexico. We performed an observational study on 25 cases diagnosed over a period of 4 years. Diagnosis of furunculoid myiasis was made in 14 males and 11 females with an average age of 24.5 years. Most of our patients were students, farmers, or housewives. The number of lesions varied from one to four. In 20% of cases, more than one parasite was present in each lesion. The scalp was the most commonly affected region (40%), followed by the trunk and the extremities. Doppler ultrasound study (DUSG) of the furuncle-like lesions confirmed the clinical diagnosis in all cases. Furunculoid myiasis is frequent in the state of Quintana Roo, Mexico. We found no association with occupation, gender, social background or age. DUSG can be used to evaluate the number of parasites per furunculoid lesion avoiding misdiagnoses and treatment delays.

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.

Complex regression Doppler optical coherence tomography

NASA Astrophysics Data System (ADS)

Elahi, Sahar; Gu, Shi; Thrane, Lars; Rollins, Andrew M.; Jenkins, Michael W.

2018-04-01

We introduce a new method to measure Doppler shifts more accurately and extend the dynamic range of Doppler optical coherence tomography (OCT). The two-point estimate of the conventional Doppler method is replaced with a regression that is applied to high-density B-scans in polar coordinates. We built a high-speed OCT system using a 1.68-MHz Fourier domain mode locked laser to acquire high-density B-scans (16,000 A-lines) at high enough frame rates (˜100 fps) to accurately capture the dynamics of the beating embryonic heart. Flow phantom experiments confirm that the complex regression lowers the minimum detectable velocity from 12.25 mm / s to 374 μm / s, whereas the maximum velocity of 400 mm / s is measured without phase wrapping. Complex regression Doppler OCT also demonstrates higher accuracy and precision compared with the conventional method, particularly when signal-to-noise ratio is low. The extended dynamic range allows monitoring of blood flow over several stages of development in embryos without adjusting the imaging parameters. In addition, applying complex averaging recovers hidden features in structural images.

Ultrahigh field magnetic resonance and colour Doppler real-time fusion imaging of the orbit--a hybrid tool for assessment of choroidal melanoma.

PubMed

Walter, Uwe; Niendorf, Thoralf; Graessl, Andreas; Rieger, Jan; Krüger, Paul-Christian; Langner, Sönke; Guthoff, Rudolf F; Stachs, Oliver

2014-05-01

A combination of magnetic resonance images with real-time high-resolution ultrasound known as fusion imaging may improve ophthalmologic examination. This study was undertaken to evaluate the feasibility of orbital high-field magnetic resonance and real-time colour Doppler ultrasound image fusion and navigation. This case study, performed between April and June 2013, included one healthy man (age, 47 years) and two patients (one woman, 57 years; one man, 67 years) with choroidal melanomas. All cases underwent 7.0-T magnetic resonance imaging using a custom-made ocular imaging surface coil. The Digital Imaging and Communications in Medicine volume data set was then loaded into the ultrasound system for manual registration of the live ultrasound image and fusion imaging examination. Data registration, matching and then volume navigation were feasible in all cases. Fusion imaging provided real-time imaging capabilities and high tissue contrast of choroidal tumour and optic nerve. It also allowed adding a real-time colour Doppler signal on magnetic resonance images for assessment of vasculature of tumour and retrobulbar structures. The combination of orbital high-field magnetic resonance and colour Doppler ultrasound image fusion and navigation is feasible. Multimodal fusion imaging promises to foster assessment and monitoring of choroidal melanoma and optic nerve disorders. • Orbital magnetic resonance and colour Doppler ultrasound real-time fusion imaging is feasible • Fusion imaging combines the spatial and temporal resolution advantages of each modality • Magnetic resonance and ultrasound fusion imaging improves assessment of choroidal melanoma vascularisation.

Measured acoustic intensities for clinical diagnostic ultrasound transducers and correlation with thermal index.

PubMed

Retz, K; Kotopoulis, S; Kiserud, T; Matre, K; Eide, G E; Sande, R

2017-08-01

To investigate if the thermal index for bone (TIB) displayed on screen is an adequate predictor for the derated spatial-peak temporal-average (I SPTA .3 ) and spatial-peak pulse-average (I SPPA .3 ) acoustic intensities in a selection of clinical diagnostic ultrasound machines and transducers. We calibrated five clinical diagnostic ultrasound scanners and 10 transducers, using two-dimensional grayscale, color Doppler and pulsed-wave Doppler, both close to and far from the transducer, with a TIB between 0.1 and 4.0, recording 103 unique measurements. Acoustic measurements were performed in a bespoke three-axis computer-controlled scanning tank, using a 200-μm-diameter calibrated needle hydrophone. There was significant but poor correlation between the acoustic intensities and the on-screen TIB. At a TIB of 0.1, the I SPTA .3 range was 0.51-50.49 mW/cm 2 and the I SPPA .3 range was 0.01-207.29 W/cm 2 . At a TIB of 1.1, the I SPTA .3 range was 19.02-309.44 mW/cm 2 and the I SPPA .3 range was 3.87-51.89 W/cm 2 . TIB is a poor predictor for I SPTA .3 and I SPPA .3 and for the potential bioeffects of clinical diagnostic ultrasound scanners. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

A brief history of ultrasound in rheumatology: where we were.

PubMed

Grassi, Walter; Filippucci, Emilio

2014-01-01

Ultrasonography in the '70s was a well-known and widely used method within several medical specialties but not in rheumatology. Initial development of the field was led by radiologists who mainly investigated the potential of ultrasound in the assessment of large joints. In the late '80s, the first studies supporting the role of ultrasound in the detection of soft tissue changes and bone erosions in the hands of patients with rheumatoid arthritis were published. In the '90s, the dramatic improvement of spatial resolution due to the new generation high frequency probes opened up new avenues for the exploration of otherwise undetectable anatomical details. Ultrasound research during this period was enhanced by the growing use of colour Doppler and power Doppler and by the first prototypes of three dimensional ultrasound. Over the last 10 years, the buzz words in ultrasound research in rheumatology have been standardisation, early diagnosis and therapy monitoring.

Color Doppler Ultrasound and Gamma Imaging of Intratumorally Injected 500 nm Iron-Silica Nanoshells

PubMed Central

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.

2013-01-01

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 non-biodegradable SiO2 and biodegradable Fe-SiO2 nanoshells were functionalized with diethylenetriamine pentaacetic acid (DTPA) ligand and radiolabeled with 111In3+ 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-111In labeling for studying silica nanoparticle biodistributions. PMID:23802554

An improved method based on wavelet coefficient correlation to filter noise in Doppler ultrasound blood flow signals

NASA Astrophysics Data System (ADS)

Wan, Renzhi; Zu, Yunxiao; Shao, Lin

2018-04-01

The blood echo signal maintained through Medical ultrasound Doppler devices would always include vascular wall pulsation signal .The traditional method to de-noise wall signal is using high-pass filter, which will also remove the lowfrequency part of the blood flow signal. Some scholars put forward a method based on region selective reduction, which at first estimates of the wall pulsation signals and then removes the wall signal from the mixed signal. Apparently, this method uses the correlation between wavelet coefficients to distinguish blood signal from wall signal, but in fact it is a kind of wavelet threshold de-noising method, whose effect is not so much ideal. In order to maintain a better effect, this paper proposes an improved method based on wavelet coefficient correlation to separate blood signal and wall signal, and simulates the algorithm by computer to verify its validity.

[Ultrasound diagnosis of congenital intrahepatic portosystemic shunt].

PubMed

Fu, Qiang; Tan, Shi; Cui, Li-gang; Zhang, Hua-bin; Bai, Zhi-yong; Jiang, Jie

2013-12-01

To investigate the ultrasonographic features of congenital intrahepatic portosystemic venous shunt (CIPSVS) and to assess the clinical value of ultrasonography in the diagnosis of CIPSVS. Six cases of CIPSVS diagnosed in our hospital between March 2010 and March 2012 and confirmed by enhanced computed tomography (CT) were retrospectively reviewed. Five of the six cases had follow-up data that was included in the analysis. Among the six CIPSVS cases, only one was classified as Park's type II and the rest were classified as Park's type III. Five cases involved the right lobe of the liver and only one case involved the left lobe. The lesion shapes included cystic, tubular, and irregular with clear contour and appeared to be anechoic on CT scan. The lesions ranged in size from 1.1*0.6 cm to 2.0*1.7 cm. For all cases, the color Doppler ultrasound images showed blood flowing from the portal vein to the hepatic vein, and single-phase spectrum was detected in the diversion channel. The differences observed in level of lesion size and blood flow velocity at the shunt from the time of examinations at diagnosis and subsequent follow-up did not reach statistical significance (P = 0.223 more than 0.05 and P = 0.930 more than 0.05 respectively). Although cases of CIPSVS are rare, they share some specific sonographic features that may help in diagnosis. Color Doppler ultrasound findings have high diagnostic accuracy and may represent a preferred modality for follow-up monitoring.

Feasibility of rotational scan ultrasound imaging by an angled high frequency transducer for the posterior segment of the eye.

PubMed

Paeng, Dong-Guk; Chang, Jin Ho; Chen, Ruimin; Humayun, Mark S; Shung, K Kirk

2009-03-01

High frequency ultrasound over 40 MHz has been used to image the anterior segment of the eye, but it is not suitable for the posterior segment due to the frequency dependent attenuation of ultrasound and thus the limitation of penetration depth. This paper proposes a novel scan method to image the posterior segment of the eye with an angled high frequency (beyond 40 MHz) ultrasound needle transducer. In this method, the needle transducer is inserted into the eye through a small incision hole (approximately 1 mm in diameter) and rotated around the axial direction to form a cone-shaped imaging plane, allowing the spatial information of retinal vessels and diagnosis of their occlusion to be displayed. The feasibility of this novel technique was tested with images of a wire phantom, a polyimide tube, and an excised pig eye obtained by manually rotating a 40-MHz PMN-PT needle transducer with a beveled tip of 45 degrees . From the results, we believe that rotational scan imaging will help expand the minimally invasive applications of high frequency ultrasound to other areas due to the capability of increased closeness of an angled needle transducer to structures of interest buried in other tissues.

3-D Ultrasound Vascularity Assessment for Breast Cancer Diagnosis

DTIC Science & Technology

1998-09-01

ultrasound imaging in discriminating benign from malignant known masses . Preliminary data analyses were completed on new trials and contributions were made...specificity of ultrasound imaging in discriminating benign from malignant known masses . Increasingly we and others will look toward expanded roles in...evaluate which Doppler signals might provide discrimination of breast cancer from benign masses and to compare 2D and 3D ultrasound display modes.

The role of trapped bubbles in kidney stone detection with the color Doppler ultrasound twinkling artifact.

PubMed

Simon, Julianna C; Sapozhnikov, Oleg A; Kreider, Wayne; Breshock, Michael; Williams, James C; Bailey, Michael R

2018-01-09

The color Doppler ultrasound twinkling artifact, which highlights kidney stones with rapidly changing color, has the potential to improve stone detection; however, its inconsistent appearance has limited its clinical utility. Recently, it was proposed stable crevice bubbles on the kidney stone surface cause twinkling; however, the hypothesis is not fully accepted because the bubbles have not been directly observed. In this paper, the micron or submicron-sized bubbles predicted by the crevice bubble hypothesis are enlarged in kidney stones of five primary compositions by exposure to acoustic rarefaction pulses or hypobaric static pressures in order to simultaneously capture their appearance by high-speed photography and ultrasound imaging. On filming stones that twinkle, consecutive rarefaction pulses from a lithotripter caused some bubbles to reproducibly grow from specific locations on the stone surface, suggesting the presence of pre-existing crevice bubbles. Hyperbaric and hypobaric static pressures were found to modify the twinkling artifact; however, the simple expectation that hyperbaric exposures reduce and hypobaric pressures increase twinkling by shrinking and enlarging bubbles, respectively, largely held for rough-surfaced stones but was inadequate for smoother stones. Twinkling was found to increase or decrease in response to elevated static pressure on smooth stones, perhaps because of the compression of internal voids. These results support the crevice bubble hypothesis of twinkling and suggest the kidney stone crevices that give rise to the twinkling phenomenon may be internal as well as external.

The role of trapped bubbles in kidney stone detection with the color Doppler ultrasound twinkling artifact

NASA Astrophysics Data System (ADS)

Simon, Julianna C.; Sapozhnikov, Oleg A.; Kreider, Wayne; Breshock, Michael; Williams, James C., Jr.; Bailey, Michael R.

2018-01-01

The color Doppler ultrasound twinkling artifact, which highlights kidney stones with rapidly changing color, has the potential to improve stone detection; however, its inconsistent appearance has limited its clinical utility. Recently, it was proposed stable crevice bubbles on the kidney stone surface cause twinkling; however, the hypothesis is not fully accepted because the bubbles have not been directly observed. In this paper, the micron or submicron-sized bubbles predicted by the crevice bubble hypothesis are enlarged in kidney stones of five primary compositions by exposure to acoustic rarefaction pulses or hypobaric static pressures in order to simultaneously capture their appearance by high-speed photography and ultrasound imaging. On filming stones that twinkle, consecutive rarefaction pulses from a lithotripter caused some bubbles to reproducibly grow from specific locations on the stone surface, suggesting the presence of pre-existing crevice bubbles. Hyperbaric and hypobaric static pressures were found to modify the twinkling artifact; however, the simple expectation that hyperbaric exposures reduce and hypobaric pressures increase twinkling by shrinking and enlarging bubbles, respectively, largely held for rough-surfaced stones but was inadequate for smoother stones. Twinkling was found to increase or decrease in response to elevated static pressure on smooth stones, perhaps because of the compression of internal voids. These results support the crevice bubble hypothesis of twinkling and suggest the kidney stone crevices that give rise to the twinkling phenomenon may be internal as well as external.

Evaluation of joint effusion in rabbits by color Doppler, power Doppler, and contrast-enhanced power Doppler ultrasonography.

PubMed

Lim, Gye-Yeon; Im, Soo Ah; Jung, Won Sang; Lee, Jae Mun; Lee, Ah Won

2005-09-01

The aim of this prospective study was to evaluate the diagnostic value of power Doppler ultrasonography (PDUS) and contrast-enhanced PDUS (CEPDUS) in the depiction and characterization of experimentally induced arthritis in the rabbit. Thirty rabbits were divided into three groups consisting of one control group (saline injection group) and two experimental groups: a suppurative arthritis group and a chemically induced synovitis group. The same amount (1 ml) of each agent was directly injected into the right hip joint. Serial color Doppler ultrasound (CDUS), PDUS, and CEPDUS images were obtained before and after injection. We observed that all of the infected knees in the suppurative arthritis group with Staphylococcus aureus demonstrated an increased signal on PDUS after inoculation. A minimal power Doppler signal was presented in the chemically induced synovitis group with talc injection, but none of the control knees demonstrated any increased signals. CEPDUS was the most sensitive imaging modality for evaluating the increase of blood flows in suppurative arthritis and was subsequently followed by PDUS and CDUS. The increased signals obtained with PDUS represent increased local blood flows; therefore, this technique can be used for evaluating the degree of inflammation. Furthermore, using the contrast agent enhances the sensitivity of PDUS, and it can even be useful for differentiating borderline cases. Copyright 2005 Wiley Periodicals, Inc

The Presto 1000: A novel automated transcranial Doppler ultrasound system.

PubMed

Han, Seunggu J; Rutledge, William Caleb; Englot, Dario J; Winkler, Ethan A; Browne, Janet L; Pflugrath, Lauren; Cronsier, David; Abla, Adib A; Kliot, Michel; Lawton, Michael T

2015-11-01

We examined the reliability and ease of use of a novel automated transcranial Doppler (TCD) system in comparison to a conventional TCD system. TCD ultrasound allows non-invasive monitoring of cerebral blood flow, and can predict arterial vasospasm after a subarachnoid hemorrhage (SAH). The Presto 1000 TCD system (PhysioSonics, Bellevue, WA, USA) is designed for monitoring flow through the M1 segment of the middle cerebral artery (MCA) via temporal windows. The Presto 1000 system was tested across multiple preclinical and clinical settings in parallel with a control predicate TCD system. In a phantom flow generating device, both the Presto 1000 and Spencer system (Spencer Technologies, Redmond, WA, USA) were able to detect velocities with high accuracy. In nine volunteer patients, the Presto system was able to locate the MCA in 14 out of 18 temporal windows, in an average of 12.5s. In the SAH cohort of five patients with a total of 25 paired measurements, the mean absolute difference in flow velocities of the M1 segment, as measured by the two systems, was 17.5 cm/s. These data suggest that the Presto system offers an automated TCD that can reliably localize and detect flow of the MCA, with relative ease of use. The system carries the additional benefit of requiring minimal training for the operator, and can be used by many providers across multiple bedside settings. The mean velocities that were generated warrant further validation across an extended group of patients, and the predictive value for vasospasm should be checked against the current standard of angiography. Copyright © 2015 Elsevier Ltd. All rights reserved.

A feasability study of color flow doppler vectorization for automated blood flow monitoring.

PubMed

Schorer, R; Badoual, A; Bastide, B; Vandebrouck, A; Licker, M; Sage, D

2017-12-01

An ongoing issue in vascular medicine is the measure of the blood flow. Catheterization remains the gold standard measurement method, although non-invasive techniques are an area of intense research. We hereby present a computational method for real-time measurement of the blood flow from color flow Doppler data, with a focus on simplicity and monitoring instead of diagnostics. We then analyze the performance of a proof-of-principle software implementation. We imagined a geometrical model geared towards blood flow computation from a color flow Doppler signal, and we developed a software implementation requiring only a standard diagnostic ultrasound device. Detection performance was evaluated by computing flow and its determinants (flow speed, vessel area, and ultrasound beam angle of incidence) on purposely designed synthetic and phantom-based arterial flow simulations. Flow was appropriately detected in all cases. Errors on synthetic images ranged from nonexistent to substantial depending on experimental conditions. Mean errors on measurements from our phantom flow simulation ranged from 1.2 to 40.2% for angle estimation, and from 3.2 to 25.3% for real-time flow estimation. This study is a proof of concept showing that accurate measurement can be done from automated color flow Doppler signal extraction, providing the industry the opportunity for further optimization using raw ultrasound data.

Added value of cerebro-placental ratio and uterine artery Doppler at routine third trimester screening as a predictor of SGA and FGR in non-selected pregnancies.

PubMed

Rial-Crestelo, M; Martinez-Portilla, R J; Cancemi, A; Caradeux, J; Fernandez, L; Peguero, A; Gratacos, E; Figueras, Francesc

2018-03-04

The objective of this study is to determine the added value of cerebroplacental ratio (CPR) and uterine Doppler velocimetry at third trimester scan in an unselected obstetric population to predict smallness and growth restriction. We constructed a prospective cohort study of women with singleton pregnancies attended for routine third trimester screening (32 +0 -34 +6 weeks). Fetal biometry and fetal-maternal Doppler ultrasound examinations were performed by certified sonographers. The CPR was calculated as a ratio of the middle cerebral artery to the umbilical artery pulsatility indices. Both attending professionals and patients were blinded to the results, except in cases of estimated fetal weight < p10. The association between third trimester Doppler parameters and small for gestational age (SGA) (birth weight <10th centile) and fetal growth restriction (FGR) (birth weight below the third centile) was assessed by logistic regression, where the basal comparison was a model comprising maternal characteristics and estimated fetal weight (EFW). A total of 1030 pregnancies were included. The mean gestational age at scan was 33 weeks (SD 0.6). The addition of CPR and uterine Doppler to maternal characteristics plus EFW improved the explained uncertainty of the predicting models for SGA (15 versus 10%, p < .001) and FGR (12 versus 8%, p = .03). However, the addition of CPR and uterine Doppler to maternal characteristics plus EFW only marginally improved the detection rates for SGA (38 versus 34% for a 10% of false positives) and did not change the predictive performance for FGR. The added value of CPR and uterine Doppler at 33 weeks of gestation for detecting defective growth is poor.

Four-dimensional Doppler ultrasound measurements in carotid bifurcation models: effect of concentric versus eccentric stenosis

NASA Astrophysics Data System (ADS)

Poepping, Tamie L.; Rankin, Richard N.; Holdsworth, David W.

2001-05-01

A unique in-vitro system has been developed that incorporates both realistic phantoms and flow. The anthropomorphic carotid phantoms are fabricated in agar with stenosis severity of 30% or 70% (by NASCET standards) and one of two geometric configurations- concentric or eccentric. The phantoms are perfused with a flow waveform that simulates normal common carotid flow. Pulsed Doppler ultrasound data are acquired at a 1 mm grid spacing throughout the lumen of the carotid bifurcation. To obtain a half-lumen volume, symmetric about the mid plane, requires a 13 hour acquisition over 3238 interrogation sites, producing 5.6 Gbytes of data. The spectral analysis produces estimates of parameters such as the peak velocity, mean velocity, spectral-broadening index, and turbulence intensity. Color-encoded or grayscale-encoded maps of these spectral parameters show distinctly different flow patterns resulting from stenoses of equal severity but different eccentricity. The most noticeable differences are seen in the volumes of the recirculation zones and the paths of the high-velocity jets. Elevated levels of turbulence intensity are also seen distal to the stenosis in the 70%-stenosed models.

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.

Combined Lorentz force and ultrasound Doppler velocimetry in a vertical convection liquid metal flow

NASA Astrophysics Data System (ADS)

Zürner, Till; Vogt, Tobias; Resagk, Christian; Eckert, Sven; Schumacher, Jörg

2017-11-01

We report experimental studies on turbulent vertical convection flow in the liquid metal alloy gallium-indium-tin. Flow measurements were conducted by a combined use of local Lorentz force velocimetry (LLFV) and ultrasound Doppler velocimetry (UDV). It is known that the forced convection flow in a duct generates a force on the LLFV magnet system, that grows proportional to the flow velocity. We show that for the slower flow of natural convection LLFV retains this linear dependence in the range of micronewtons. Furthermore experimental results on the scaling of heat and momentum transport with the thermal driving are presented. The results cover a range of Rayleigh numbers 3 ×105 < Ra < 3 ×107 at a Prandtl number Pr 0.032 . The Nusselt number Nu is found to scale as Nu Ra0.31 . A Reynolds number Rez based on the vertical velocities close the heated and cooled side walls scales with Rez Ra0.45 . Additionally a Reynolds number based on the horizontal flow component is scaling as Rex Ra0.67 . These results agree well with numerical simulations and theoretical predictions. This work is funded by the Deutsche Forschungsgemeinschaft under Grant No. GRK 1567.

Distinguishing Buried Objects in Extremely Shallow Underground by Frequency Response Using Scanning Laser Doppler Vibrometer

NASA Astrophysics Data System (ADS)

Abe, Touma; Sugimoto, Tsuneyoshi

2010-07-01

A sound wave vibration using a scanning laser Doppler vibrometer are used as a method of exploring and imaging an extremely shallow underground. Flat speakers are used as a vibration source. We propose a method of distinguishing a buried object using a response range of a frequencies corresponding to a vibration velocities. Buried objects (plastic containers, a hollow steel can, an unglazed pot, and a stone) are distinguished using a response range of frequencies. Standardization and brightness imaging are used as methods of discrimination. As a result, it was found that the buried objects show different response ranges of frequencies. From the experimental results, we confirmed the effectiveness of our proposed method.

Dove prism based rotating dual beam bidirectional Doppler OCT

PubMed Central

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

2013-01-01

Traditional Doppler OCT is highly sensitive to motion artifacts due to the dependence on the Doppler angle. This limits its accuracy in clinical practice. To overcome this limitation, we use a bidirectional dual beam technique equipped with a novel rotating scanning scheme employing a Dove prism. The volume is probed from two distinct illumination directions with variable controlled incidence plane, allowing for reconstruction of the true flow velocity at arbitrary vessel orientations. The principle is implemented with Swept Source OCT at 1060nm with 100,000 A-Scans/s. We apply the system to resolve pulsatile retinal absolute blood velocity by performing segment scans around the optic nerve head and circumpapillary scan time series. PMID:23847742

Feasibility of Rotational Scan Ultrasound Imaging by an Angled High Frequency Transducer for the Posterior Segment of the Eye

PubMed Central

Paeng, Dong-Guk; Chang, Jin Ho; Chen, Ruimin; Humayun, Mark S.; Shung, K. Kirk

2009-01-01

High frequency ultrasound over 40 MHz has been used to image the anterior segment of the eye, but it is not suitable for the posterior segment due to the frequency-dependent attenuation of ultrasound and thus the limitation of penetration depth. This paper proposes a novel scan method to image the posterior segment of the eye with an angled high frequency (beyond 40 MHz) ultrasound needle transducer. In this method, the needle transducer is inserted into the eye through a small incision hole (∼1 mm in diameter) and rotated around the axial direction to form a cone-shaped imaging plane, allowing the spatial information of retinal vessels and diagnosis of their occlusion to be displayed. The feasibility of this novel technique was tested with images of a wire phantom, a polyimide tube, and an excised pig eye obtained by manually rotating a 40-MHz PMN-PT needle transducer with a beveled tip of 45°. From the results, we believe that rotational scan imaging will help expand the minimally invasive applications of high frequency ultrasound to other areas due to the capability of increased closeness of an angled needle transducer to structures of interest buried in other tissues. PMID:19411226

Ultrasound Thermal Field Imaging of Opaque Fluids

NASA Technical Reports Server (NTRS)

Andereck, C. David

1999-01-01

We have initiated an experimental program to develop an ultrasound system for non-intrusively imaging the thermal field in opaque fluids under an externally imposed temperature gradient. Many industrial processes involve opaque fluids, such as molten metals, semiconductors, and polymers, often in situations in which thermal gradients are important. For example, one may wish to understand semiconductor crystal growth dynamics in a Bridgman apparatus. Destructive testing of the crystal after the process is completed gives only indirect information about the fluid dynamics of the formation process. Knowledge of the coupled thermal and velocity fields during the growth process is then essential. Most techniques for non-intrusive velocity and temperature measurement in fluids are optical in nature, and hence the fluids studied must be transparent. In some cases (for example, LDV (laser Doppler velocimetry) and PIV (particle imaging velocimetry)) the velocities of small neutrally buoyant seed particles suspended in the fluid, are measured. Without particle seeding one can use the variation of the index of refraction of the fluid with temperature to visualize, through interferometric, Schlieren or shadowgraph techniques, the thermal field. The thermal field in turn gives a picture of the pattern existing in the fluid. If the object of study is opaque, non-optical techniques must be used. In this project we focus on the use of ultrasound, which propagates easily through opaque liquids and solids. To date ultrasound measurements have almost exclusively relied on the detection of sound scattered from density discontinuities inside the opaque material of interest. In most cases it has been used to visualize structural properties, but more recently the ultrasound Doppler velocimeter has become available. As in the optical case, it relies on seed particles that scatter Doppler shifted sound back to the detector. Doppler ultrasound techniques are, however, not useful for

Power Doppler signal calibration between ultrasound machines by use of a capillary-flow phantom for pannus vascularity in rheumatoid finger joints: a basic study.

PubMed

Sakano, Ryosuke; Kamishima, Tamotsu; Nishida, Mutsumi; Horie, Tatsunori

2015-01-01

Ultrasound allows the detection and grading of inflammation in rheumatology. Despite these advantages of ultrasound in the management of rheumatoid patients, it is well known that there are significant machine-to-machine disagreements regarding signal quantification. In this study, we tried to calibrate the power Doppler (PD) signal of two models of ultrasound machines by using a capillary-flow phantom. After flow velocity analysis in the perfusion cartridge at various injection rates (0.1-0.5 ml/s), we measured the signal count in the perfusion cartridge at various injection rates and pulse repetition frequencies (PRFs) by using PD, perfusing an ultrasound micro-bubble contrast agent diluted with normal saline simulating human blood. By use of the data from two models of ultrasound machines, Aplio 500 (Toshiba) and Avius (Hitachi Aloka), the quantitative PD (QPD) index [the summation of the colored pixels in a 1 cm × 1 cm rectangular region of interest (ROI)] was calculated via Image J (internet free software). We found a positive correlation between the injection rate and the flow velocity. In Aplio 500 and Avius, we found negative correlations between the PRF and the QPD index when the flow velocity was constant, and a positive correlation between flow velocity and the QPD index at constant PRF. The equation for the relationship of the PRF between Aplio 500 and Avius was: y = 0.023x + 0.36 [y = PRF of Avius (kHz), x = PRF of Aplio 500 (kHz)]. Our results suggested that the signal calibration of various models of ultrasound machines is possible by adjustment of the PRF setting.

Preferences for a third-trimester ultrasound scan in a low-risk obstetric population: a discrete choice experiment.

PubMed

Lynn, Fiona A; Crealey, Grainne E; Alderdice, Fiona A; McElnay, James C

2015-10-01

Establish maternal preferences for a third-trimester ultrasound scan in a healthy, low-risk pregnant population. Cross-sectional study incorporating a discrete choice experiment. A large, urban maternity hospital in Northern Ireland. One hundred and forty-six women in their second trimester of pregnancy. A discrete choice experiment was designed to elicit preferences for four attributes of a third-trimester ultrasound scan: health-care professional conducting the scan, detection rate for abnormal foetal growth, provision of non-medical information, cost. Additional data collected included age, marital status, socio-economic status, obstetric history, pregnancy-specific stress levels, perceived health and whether pregnancy was planned. Analysis was undertaken using a mixed logit model with interaction effects. Women's preferences for, and trade-offs between, the attributes of a hypothetical scan and indirect willingness-to-pay estimates. Women had significant positive preference for higher rate of detection, lower cost and provision of non-medical information, with no significant value placed on scan operator. Interaction effects revealed subgroups that valued the scan most: women experiencing their first pregnancy, women reporting higher levels of stress, an adverse obstetric history and older women. Women were able to trade on aspects of care and place relative importance on clinical, non-clinical outcomes and processes of service delivery, thus highlighting the potential of using health utilities in the development of services from a clinical, economic and social perspective. Specifically, maternal preferences exhibited provide valuable information for designing a randomized trial of effectiveness and insight for clinical and policy decision makers to inform woman-centred care. © 2013 Blackwell Publishing Ltd.

Microbubble-enhanced ultrasound to demonstrate urethral transection in a case of penile fracture.

PubMed

Czarnecki, Oliver; von Stempel, Conrad Brice; Sangster, Pippa; Walkden, Miles

2017-09-23

A 47-year-old man attended the emergency department following trauma during sexual intercourse after which he developed penile swelling and haematuria several hours later. A penile fracture was suspected but given the slightly atypical history, ultrasound was performed to look for a fracture. Given the history of haematuria, both a standard Doppler ultrasound and a microbubble-enhanced retrograde ultrasound urethrogram were performed. The Doppler confirmed the suspected diagnosis of penile fracture, and microbubble urethrogram demonstrated a urethral injury. This facilitated prompt surgical treatment and helped guide the surgical approach. Retrograde microbubble enhanced ultrasound urethrogram is a novel technique that can be used in conjunction with standard ultrasound to confirm the presence of a concurrent urethral rupture in penile fracture. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

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.

Clinical Tests Combined with Color Doppler Versus Color Doppler Alone in Identifying Incompetent Perforator Veins of the Lower Limb: A Prospective Analytical Study.

PubMed

Sureshkumar, Sathasivam; Vignesh, Narayan; Venkatachalam, J; Vijayakumar, Chellappa; Sudharsanan, Sundaramurthi

2018-01-05

Background The color Doppler, a better investigation to identify the perforators objectively has replaced the clinical examination for the same. However, this has led to a significant number of negative explorations and cosmetic disfigurement. Objective To compare the efficacy of the clinical tests combined with the color Doppler versus color Doppler alone to identify the perforator incompetence during the surgery for primary varicose veins of the lower limb. Methods This was a prospective analytical study, including 61 lower limb varicose vein patients who belonged to the Clinical-Etiology-Anatomy-Pathophysiology (CEAP) class four-six, planned for the surgical treatment for perforator incompetence, excluding those requiring additional vascular or nonvascular procedure, recurrent varicose veins and those who had injection sclerotherapy prior to the surgery. The clinical tests, including Trendelenburg's test, multiple tourniquet tests and, the Fegan's tests were performed and incompetent perforators were marked on a template as 'C' to indicate the clinically positive perforator incompetence. The patients were then examined with the color Doppler ultrasound and the pathological incompetent perforators were marked as 'D'. The surgical management of the perforator incompetence was done by stab ligation. The incision was made in the color Doppler 'D' marked sites as it has been the standard protocol. The number of incompetent perforators identified during the surgical exploration were categorized as 'D' positive or 'C' and 'D' positive and were recorded in the specified proforma. Results It was found that the mean number of the perforator incompetence identified by the color Doppler alone was 8.2 whereas during the surgery, only a mean of six perforators was identified, leading to 20 unnecessary explorations per 10 patients (8.2 vs. 6; mean difference 2.229; P <0.001). The mean number of the perforator incompetence identified by the color Doppler combined with the

Clinical Tests Combined with Color Doppler Versus Color Doppler Alone in Identifying Incompetent Perforator Veins of the Lower Limb: A Prospective Analytical Study

PubMed Central

Vignesh, Narayan; Venkatachalam, J; Vijayakumar, Chellappa; Sudharsanan, Sundaramurthi

2018-01-01

Background The color Doppler, a better investigation to identify the perforators objectively has replaced the clinical examination for the same. However, this has led to a significant number of negative explorations and cosmetic disfigurement. Objective To compare the efficacy of the clinical tests combined with the color Doppler versus color Doppler alone to identify the perforator incompetence during the surgery for primary varicose veins of the lower limb. Methods This was a prospective analytical study, including 61 lower limb varicose vein patients who belonged to the Clinical-Etiology-Anatomy-Pathophysiology (CEAP) class four-six, planned for the surgical treatment for perforator incompetence, excluding those requiring additional vascular or nonvascular procedure, recurrent varicose veins and those who had injection sclerotherapy prior to the surgery. The clinical tests, including Trendelenburg’s test, multiple tourniquet tests and, the Fegan’s tests were performed and incompetent perforators were marked on a template as ‘C’ to indicate the clinically positive perforator incompetence. The patients were then examined with the color Doppler ultrasound and the pathological incompetent perforators were marked as ‘D’. The surgical management of the perforator incompetence was done by stab ligation. The incision was made in the color Doppler ‘D’ marked sites as it has been the standard protocol. The number of incompetent perforators identified during the surgical exploration were categorized as ‘D’ positive or ’C’ and ‘D’ positive and were recorded in the specified proforma. Results It was found that the mean number of the perforator incompetence identified by the color Doppler alone was 8.2 whereas during the surgery, only a mean of six perforators was identified, leading to 20 unnecessary explorations per 10 patients (8.2 vs. 6; mean difference 2.229; P <0.001). The mean number of the perforator incompetence identified by the color

Is Abdominal Fetal Electrocardiography an Alternative to Doppler Ultrasound for FHR Variability Evaluation?

PubMed Central

Jezewski, Janusz; Wrobel, Janusz; Matonia, Adam; Horoba, Krzysztof; Martinek, Radek; Kupka, Tomasz; Jezewski, Michal

2017-01-01

Great expectations are connected with application of indirect fetal electrocardiography (FECG), especially for home telemonitoring of pregnancy. Evaluation of fetal heart rate (FHR) variability, when determined from FECG, uses the same criteria as for FHR signal acquired classically—through ultrasound Doppler method (US). Therefore, the equivalence of those two methods has to be confirmed, both in terms of recognizing classical FHR patterns: baseline, accelerations/decelerations (A/D), long-term variability (LTV), as well as evaluating the FHR variability with beat-to-beat accuracy—short-term variability (STV). The research material consisted of recordings collected from 60 patients in physiological and complicated pregnancy. The FHR signals of at least 30 min duration were acquired dually, using two systems for fetal and maternal monitoring, based on US and FECG methods. Recordings were retrospectively divided into normal (41) and abnormal (19) fetal outcome. The complex process of data synchronization and validation was performed. Obtained low level of the signal loss (4.5% for US and 1.8% for FECG method) enabled to perform both direct comparison of FHR signals, as well as indirect one—by using clinically relevant parameters. Direct comparison showed that there is no measurement bias between the acquisition methods, whereas the mean absolute difference, important for both visual and computer-aided signal analysis, was equal to 1.2 bpm. Such low differences do not affect the visual assessment of the FHR signal. However, in the indirect comparison the inconsistencies of several percent were noted. This mainly affects the acceleration (7.8%) and particularly deceleration (54%) patterns. In the signals acquired using the electrocardiography the obtained STV and LTV indices have shown significant overestimation by 10 and 50% respectively. It also turned out, that ability of clinical parameters to distinguish between normal and abnormal groups do not depend on

Diagnostic ultrasound imaging for lateral epicondylalgia: a case-control study.

PubMed

Heales, Luke James; Broadhurst, Nathan; Mellor, Rebecca; Hodges, Paul William; Vicenzino, Bill

2014-11-01

Lateral epicondylalgia (LE) is clinically diagnosed as pain over the lateral elbow that is provoked by gripping. Usually, LE responds well to conservative intervention; however, those who fail such treatment require further evaluation, including musculoskeletal ultrasound. Previous studies of musculoskeletal ultrasound have methodological flaws, such as lack of assessor blinding and failure to control for participant age, sex, and arm dominance. The purpose of this study was to assess the diagnostic use of blinded ultrasound imaging in people with clinically diagnosed LE compared with that in a control group matched for age, sex, and arm dominance. Participants (30 with LE and 30 controls) underwent clinical examination as the criterion standard test. Unilateral LE was defined as pain over the lateral epicondyle, which was provoked by palpation, resisted wrist and finger extension, and gripping. Controls without symptoms were matched for age, sex, and arm dominance. Ultrasound investigations were performed by two sonographers using a standardized protocol. Grayscale images were assessed for signs of tendon pathology and rated on a four-point ordinal scale. Power Doppler was used to assess neovascularity and rated on a five-point ordinal scale. The combination of grayscale and power Doppler imaging revealed an overall sensitivity of 90% and specificity of 47%. The positive and negative likelihood ratios for combined grayscale and power Doppler imaging were 1.69 and 0.21, respectively. Although ultrasound imaging helps confirm the absence of LE, when findings are negative for tendinopathic changes, the high prevalence of tendinopathic changes in pain-free controls challenges the specificity of the measure. The validity of ultrasound imaging to confirm tendon pathology in clinically diagnosed LE requires further study with strong methodology.

Imaging-based assessment of the mineral composition of urinary stones: an in vitro study of the combination of hounsfield unit measurement in noncontrast helical computerized tomography and the twinkling artifact in color Doppler ultrasound.

PubMed

Hassani, Hakim; Raynal, Gauthier; Spie, Romain; Daudon, Michel; Vallée, Jean-Noël

2012-05-01

We evaluated the value of combining noncontrast helical computerized tomography (NCHCT) and color Doppler ultrasound in the assessment of the composition of urinary stones. In vitro, we studied 120 stones of known composition, that separate into the five main types: 18 calcium oxalate monohydrate (COM) stones, 41 calcium oxalate dihydrate (COD) stones, 24 uric acid stones, 25 calcium phosphate stones and 12 cystine calculi. Stones were characterized in terms of their Hounsfield density (HU) in NCHCT and the presence of a twinkling artifact (TA) in color Doppler ultrasound. There were statistically significant HU differences between calcium and non-calcium stones (p < 0.001), calcium oxalate stones and calcium phosphate stones (p < 0.001) and uric acid stones and cystine calculi (p < 0.001) but not between COM and COD stones (p = 0.786). Hence, the HU was a predictive factor of the composition of all types of stones, other than for COM and COD stones within the calcium oxalate class (p > 0.05). We found that the TA does not enable differentiation between calcium and non-calcium stones (p > 0.999), calcium oxalate stones and calcium phosphate stones (p = 0.15), or uric acid stones and cystine calculi (p = 0.079). However, it did reveal a significant difference between COM and COD stones (p = 0.002). The absence of a TA is a predictive factor for the presence of COM stones (p = 0.008). Hence, the association of NCHCT and Doppler enables the accurate classification of the five types of stones in vitro. Copyright © 2012 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Transjugular Intrahepatic Portosystemic Shunt Dysfunction: Concordance of Clinical Findings, Doppler Ultrasound Examination, and Shunt Venography.

PubMed

Owen, Joshua M; Gaba, Ron Charles

2016-01-01

The objective of this study was to evaluate the concordance between clinical symptoms, Doppler ultrasound (US), and shunt venography for the detection of stent-graft transjugular intrahepatic portosystemic shunt (TIPS) dysfunction. Forty-one patients (M:F 30:11, median age 55 years) who underwent contemporaneous clinical exam, Doppler US, and TIPS venography between 2003 and 2014 were retrospectively studied. Clinical symptoms (recurrent ascites or variceal bleeding) were dichotomously classified as present/absent, and US and TIPS venograms were categorized in a binary fashion as normal/abnormal. US abnormalities included high/low (>190 or <90 cm/s) TIPS velocity, significant velocity rise/fall (>50 cm/s), absent flow, and return of antegrade intra-hepatic portal flow. Venographic abnormalities included shunt stenosis/occlusion and/or pressure gradient elevation. Clinical and imaging concordance rates were calculated. Fifty-two corresponding US examinations and venograms were assessed. The median time between studies was 3 days. Forty of 52 (77%) patients were symptomatic, 33/52 (64%) US examinations were abnormal, and 20/52 (38%) TIPS venograms were abnormal. Concordance between clinical symptoms and TIPS venography was 48% (25/52), while the agreement between US and shunt venography was 65% (34/52). Clinical symptoms and the US concurred in 60% (31/52) of the patients. The sensitivity of clinical symptoms and US for the detection of venographically abnormal shunts was 80% (16/20) and 85% (17/20), respectively. Both clinical symptoms and the US had low specificity (25%, 8/32 and 50%, 16/32) for venographically abnormal shunts. Clinical findings and the US had low concordance rates with TIPS venography, with acceptable sensitivity but poor specificity. These findings suggest the need for improved noninvasive imaging methods for stent-graft TIPS surveillance.

Transjugular Intrahepatic Portosystemic Shunt Dysfunction: Concordance of Clinical Findings, Doppler Ultrasound Examination, and Shunt Venography

PubMed Central

Owen, Joshua M; Gaba, Ron Charles

2016-01-01

Objectives: The objective of this study was to evaluate the concordance between clinical symptoms, Doppler ultrasound (US), and shunt venography for the detection of stent-graft transjugular intrahepatic portosystemic shunt (TIPS) dysfunction. Materials and Methods: Forty-one patients (M:F 30:11, median age 55 years) who underwent contemporaneous clinical exam, Doppler US, and TIPS venography between 2003 and 2014 were retrospectively studied. Clinical symptoms (recurrent ascites or variceal bleeding) were dichotomously classified as present/absent, and US and TIPS venograms were categorized in a binary fashion as normal/abnormal. US abnormalities included high/low (>190 or <90 cm/s) TIPS velocity, significant velocity rise/fall (>50 cm/s), absent flow, and return of antegrade intra-hepatic portal flow. Venographic abnormalities included shunt stenosis/occlusion and/or pressure gradient elevation. Clinical and imaging concordance rates were calculated. Results: Fifty-two corresponding US examinations and venograms were assessed. The median time between studies was 3 days. Forty of 52 (77%) patients were symptomatic, 33/52 (64%) US examinations were abnormal, and 20/52 (38%) TIPS venograms were abnormal. Concordance between clinical symptoms and TIPS venography was 48% (25/52), while the agreement between US and shunt venography was 65% (34/52). Clinical symptoms and the US concurred in 60% (31/52) of the patients. The sensitivity of clinical symptoms and US for the detection of venographically abnormal shunts was 80% (16/20) and 85% (17/20), respectively. Both clinical symptoms and the US had low specificity (25%, 8/32 and 50%, 16/32) for venographically abnormal shunts. Conclusion: Clinical findings and the US had low concordance rates with TIPS venography, with acceptable sensitivity but poor specificity. These findings suggest the need for improved noninvasive imaging methods for stent-graft TIPS surveillance. PMID:27563495

Ultrasonographic investigation of the Achilles tendon in elite badminton players using color Doppler.

PubMed

Boesen, Morten Ilum; Boesen, Anders; Koenig, Merete Juhl; Bliddal, Henning; Torp-Pedersen, Soren

2006-12-01

The most frequent injuries in badminton players are in the lower extremities, especially in the Achilles tendon. The game of badminton may be related to abnormal intratendinous flow in the Achilles tendon as detected by color Doppler ultrasound. To a certain extent, this blood flow might be physiological, especially when examined after match. Cohort study (prevalence); Level of evidence, 3. Seventy-two elite badminton players were interviewed regarding Achilles tendon pain (achillodynia) in the preceding 3 years. Color Doppler was used to examine the tendons of 64 players before their matches and 46 players after their matches. Intratendinous color Doppler flow was graded from 0 to 4. The Achilles tendon was divided into dominant (eg, right side for right-handed players and vice versa) and nondominant side and classified as midtendon, preinsertional, and calcaneal areas. Of 72 players, 26 had experienced achillodynia in 34 tendons, 18 on the dominant side and 16 on the nondominant side. In 62% of the players with achillodynia, the problems had begun slowly, and the median duration of symptoms was 4 months (range, 0-36 months). Thirty-five percent had ongoing pain in their tendons for a median duration of 12 months (range, 0-12 months). Achillodynia was not associated with the self-reported training load or with sex, age, weight, singles or doubles players, or racket side. Forty-six players were scanned before and after match. At baseline, color Doppler flow was present in the majority of players, and only 7 (16%) players had no color Doppler flow in either tendon. After match, all players had some color Doppler flow in 1 or both tendons. Achillodynia and color Doppler flow were related in the nondominant Achilles tendon (chi-square, P = .008). The grades of Doppler flow also increased significantly after match in the preinsertional area in both the nondominant (P = .0002) and dominant (P = .005) side tendons. A large proportion of the players had experienced

Automated ultrasound scanning on a dual-modality breast imaging system: coverage and motion issues and solutions.

PubMed

Sinha, Sumedha P; Goodsitt, Mitchell M; Roubidoux, Marilyn A; Booi, Rebecca C; LeCarpentier, Gerald L; Lashbrook, Christine R; Thomenius, Kai E; Chalek, Carl L; Carson, Paul L

2007-05-01

We are developing an automated ultrasound imaging-mammography system wherein a digital mammography unit has been augmented with a motorized ultrasound transducer carriage above a special compression paddle. Challenges of this system are acquiring complete coverage of the breast and minimizing motion. We assessed these problems and investigated methods to increase coverage and stabilize the compressed breast. Visual tracings of the breast-to-paddle contact area and breast periphery were made for 10 patients to estimate coverage area. Various motion artifacts were evaluated in 6 patients. Nine materials were tested for coupling the paddle to the breast. Fourteen substances were tested for coupling the transducer to the paddle in lateral-to-medial and medial-to-lateral views and filling the gap between the peripheral breast and paddle. In-house image registration software was used to register adjacent ultrasound sweeps. The average breast contact area was 56%. The average percentage of the peripheral air gap filled with ultrasound gel was 61%. Shallow patient breathing proved equivalent to breath holding, whereas speech and sudden breathing caused unacceptable artifacts. An adhesive spray that preserves image quality was found to be best for coupling the breast to the paddle and minimizing motion. A highly viscous ultrasound gel proved most effective for coupling the transducer to the paddle for lateral-to-medial and medial-to-lateral views and for edge fill-in. The challenges of automated ultrasound scanning in a multimodality breast imaging system have been addressed by developing methods to fill in peripheral gaps, minimize patient motion, and register and reconstruct multisweep ultrasound image volumes.

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.

Transcranial Doppler ultrasound study of the effects of nitrous oxide on cerebral autoregulation during neurosurgical anesthesia: a randomized controlled trial.

PubMed

Iacopino, Domenico G; Conti, Alfredo; Battaglia, Calogero; Siliotti, Clotilde; Lucanto, Tullio; Santamaria, Letterio B; Tomasello, Francesco

2003-07-01

Nitrous oxide has an adverse effect on cerebrovascular hemodynamics. Increased intracranial pressure, cerebral blood flow (CBF), cerebral metabolic rate of O2 (CMRO2), and reduced autoregulation indices have been reported, but their magnitudes are still being debated. This study was designed to evaluate the effect of N2O on CBF and autoregulatory indexes during N2O-sevoflurane anesthesia in a prospective randomized controlled series of patients. Two groups of 20 patients were studied on the basis of the use of N2O in the anesthetic gas mixture. The transient hyperemic response test, which relies on transcranial Doppler ultrasound techniques, was used to assess cerebral hemodynamics. The time-averaged mean flow velocity, considered to be an index of actual CBF, increased significantly (p < 0.001) after introduction of N2O. The hyperemic response, considered as the index of autoregulatory potential, decreased significantly after introduction of N2O into the gas mixture (p < 0.001). The increase in CBF and the reduction in autoregulatory indices suggest caution in using N2O during sevoflurane anesthesia, especially in patients with reduced autoregulatory reserve and during neurosurgical interventions. Transcranial Doppler ultrasonography is an efficacious method to evaluate the effects of anesthetic agents on CBF.

Detection of cavernous transformation of the portal vein by contrast-enhanced ultrasound.

PubMed

Hwang, Misun; Thimm, Matthew A; Guerrerio, Anthony L

2018-06-01

Cavernous transformation of the portal vein can be missed on color Doppler exam or arterial phase cross-sectional imaging due to their slow flow and delayed enhancement. Contrast-enhanced ultrasound (CEUS) offers many advantages over other imaging techniques and can be used to successfully detect cavernous transformations of the portal vein. A 10-month-old female was followed for repeat episodes of hematemesis. Computed tomography angiography (CTA) and magnetic resonance arteriogram (MRA) and portal venography were performed. Color Doppler exam of the portal vein was performed followed by administration of Lumason, a microbubble US contrast agent. Magnetic resonance arteriogram, CTA, and color Doppler exam at the time of initial presentation was unremarkable without obvious vascular malformation within the limits of motion degraded exam. At 8-month follow-up, esophagogastroduodenoscopy revealed a vascular malformation in the distal esophagus which was sclerosed. At 6 month after sclerosis of the lesion, portal venography revealed occlusion of the portal vein with extensive collateralization. Color Doppler revealed subtle hyperarterialization and periportal collaterals. CEUS following color Doppler exam demonstrated extensive enhancement of periportal collaterals. Repeat color Doppler after contrast administration demonstrated extensive Doppler signal in the collateral vessels, suggestive of cavernous transformation. We describe a case of cavernous transformation of the portal vein missed on initial color Doppler, CTA and MRA, but detected with contrast-enhanced ultrasound technique.

Optical detection of ultrasound using an apertureless near-field scanning optical microscopy system

NASA Astrophysics Data System (ADS)

Ahn, Phillip; Zhang, Zhen; Sun, Cheng; Balogun, Oluwaseyi

2013-01-01

Laser ultrasonics techniques are power approaches for non-contact generation and detection of high frequency ultrasound on a local scale. In these techniques, optical diffraction limits the spatial information that can be accessed from a measurement. In order to improve the lateral spatial resolution, we incorporate an apertureless near-field scanning optical microscope (aNSOM) into laser ultrasonics setup for local detection of laser generated ultrasound. The aNSOM technique relies on the measurement of a weak backscattered near-field light intensity resulting from the oblique illumination of a nanoscale probe-tip positioned close to a sample surface. We enhance the optical near-field intensity by coupling light to surface plasmon polaritons (SPPs) on the shaft of an atomic force microscopy (AFM) cantilever. The SPPs propagate down the AFM shaft, localize at the tip apex, and are backscattered to the far-field when the separation distance between the probe tip and the sample surface is comparable to the probe-tip radius. The backscattered near-field intensity is dynamically modulated when an ultrasonic wave arrives at the sample surface leading to a transient change in the tip-sample separation distance. We present experimental results detailing measurement of broadband and narrowband laser generated ultrasound in solids with frequencies reaching up to 180 MHz range.

Identification of damage in plates using full-field measurement with a continuously scanning laser Doppler vibrometer system

NASA Astrophysics Data System (ADS)

Chen, Da-Ming; Xu, Y. F.; Zhu, W. D.

2018-05-01

An effective and reliable damage identification method for plates with a continuously scanning laser Doppler vibrometer (CSLDV) system is proposed. A new constant-speed scan algorithm is proposed to create a two-dimensional (2D) scan trajectory and automatically scan a whole plate surface. Full-field measurement of the plate can be achieved by applying the algorithm to the CSLDV system. Based on the new scan algorithm, the demodulation method is extended from one dimension for beams to two dimensions for plates to obtain a full-field operating deflection shape (ODS) of the plate from velocity response measured by the CSLDV system. The full-field ODS of an associated undamaged plate is obtained by using polynomials with proper orders to fit the corresponding full-field ODS from the demodulation method. A curvature damage index (CDI) using differences between curvatures of ODSs (CODSs) associated with ODSs that are obtained by the demodulation method and the polynomial fit is proposed to identify damage. An auxiliary CDI obtained by averaging CDIs at different excitation frequencies is defined to further assist damage identification. An experiment of an aluminum plate with damage in the form of 10.5% thickness reduction in a damage area of 0.86% of the whole scan area is conducted to investigate the proposed method. Six frequencies close to natural frequencies of the plate and one randomly selected frequency are used as sinusoidal excitation frequencies. Two 2D scan trajectories, i.e., a horizontally moving 2D scan trajectory and a vertically moving 2D scan trajectory, are used to obtain ODSs, CODSs, and CDIs of the plate. The damage is successfully identified near areas with consistently high values of CDIs at different excitation frequencies along the two 2D scan trajectories; the damage area is also identified by auxiliary CDIs.

Contrast-enhanced power Doppler endosonography and pathological assessment of vascularization in advanced gastric carcinomas--a feasibility study.

PubMed

Iordache, Sevastiţa; Filip, Maria-Monalisa; Georgescu, Claudia-Valentina; Angelescu, Cristina; Ciurea, Tudorel; Săftoiu, Adrian

2012-06-01

Besides representing angiogenesis markers, microvascular density (MVD) and vascular endothelial growth factor (VEGF) are two important tools for the assessment of prognosis in patients with gastric cancer. The aim of our study was to assess the Doppler parameters (resistivity and pulsatility indexes) and vascularity index (VI) calculated by contrast-enhanced power Doppler endoscopic ultrasound (CEPD-EUS) in correlation with the expression of intra-tumoral MVD and VEGF in patients with gastric cancer. The study included 20 consecutive patients with advanced gastric carcinoma, but without distant metastasis at initial assessment. All the patients were assessed by contrast-enhanced power Doppler endoscopic ultrasound (EUS) combined with pulsed Doppler examinations in the late venous phase. The vascularity index (VI) was calculated before and after injection of second generation microbubble contrast specific agent (SonoVue 2.4 mL), used as a Doppler signal enhancer. Moreover, pulsed Doppler parameters (resistivity and pulsatility indexes) were further calculated. The correlation between power Doppler parameters and pathological/molecular parameters (MVD assessed through immunohistochemistry with CD31 and CD34, as well as VEGF assessed through real-time PCR) was assessed. Kaplan-Meier survival analysis was used for the assessment of prognosis. Significantly statistical correlations were found between post-contrast VI and CD34 (p=0.0226), VEGF (p=0.0231), VEGF-A (p=0.0464) and VEGF-B (p=0.0022) while pre-contrast VI was correlated only with CD34 expression. Pulsatility index and resistivity index were not correlated with MVD or VEGF expression. Survival analysis demonstrated that VEGF-A is an accurate parameter for survival rate (p=0.045), as compared to VEGF (p=0.085) and VEGF-B (p=0.230). We did not find any correlation between the survival rate and ultrasound parameters (RI, PI, pre-contrast VI or post-contrast VI). Assessment of tumor vascularity using contrast

Gallbladder radionuclide scan

MedlinePlus

... Gallbladder scan; Biliary scan; Cholescintigraphy; HIDA; Hepatobiliary nuclear imaging scan ... test results. This test is combined with other imaging (such as CT or ultrasound). After the gallbladder ...

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.

Ultrasound-detected bone erosion is a relapse risk factor after discontinuation of biologic disease-modifying antirheumatic drugs in patients with rheumatoid arthritis whose ultrasound power Doppler synovitis activity and clinical disease activity are well controlled.

PubMed

Kawashiri, Shin-Ya; Fujikawa, Keita; Nishino, Ayako; Okada, Akitomo; Aramaki, Toshiyuki; Shimizu, Toshimasa; Umeda, Masataka; Fukui, Shoichi; Suzuki, Takahisa; Koga, Tomohiro; Iwamoto, Naoki; Ichinose, Kunihiro; Tamai, Mami; Mizokami, Akinari; Nakamura, Hideki; Origuchi, Tomoki; Ueki, Yukitaka; Aoyagi, Kiyoshi; Maeda, Takahiro; Kawakami, Atsushi

2017-05-25

In the present study, we explored the risk factors for relapse after discontinuation of biologic disease-modifying antirheumatic drug (bDMARD) therapy in patients with rheumatoid arthritis (RA) whose ultrasound power Doppler (PD) synovitis activity and clinical disease activity were well controlled. In this observational study in clinical practice, the inclusion criteria were based on ultrasound disease activity and clinical disease activity, set as low or remission (Disease Activity Score in 28 joints based on erythrocyte sedimentation rate <3.2). Ultrasound was performed in 22 joints of bilateral hands at discontinuation for evaluating synovitis severity and presence of bone erosion. Patients with a maximum PD score ≤1 in each joint were enrolled. Forty patients with RA were consecutively recruited (November 2010-March 2015) and discontinued bDMARD therapy. Variables at the initiation and discontinuation of bDMARD therapy that were predictive of relapse during the 12 months after discontinuation were assessed. The median patient age was 54.5 years, and the median disease duration was 3.5 years. Nineteen (47.5%) patients relapsed during the 12 months after the discontinuation of bDMARD therapy. Logistic regression analysis revealed that only the presence of bone erosion detected by ultrasound at discontinuation was predictive of relapse (OR 8.35, 95% CI 1.78-53.2, p = 0.006). No clinical characteristics or serologic biomarkers were significantly different between the relapse and nonrelapse patients. The ultrasound synovitis scores did not differ significantly between the groups. Our findings are the first evidence that ultrasound bone erosion may be a relapse risk factor after the discontinuation of bDMARD therapy in patients with RA whose PD synovitis activity and clinical disease activity are well controlled.

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.

Vascularization of liver tumors - preliminary results with Coded Harmonic Angio (CHA), phase inversion imaging, 3D power Doppler and contrast medium-enhanced B-flow with second generation contrast agent (Optison).

PubMed

Jung, E M; Kubale, R; Jungius, K-P; Jung, W; Lenhart, M; Clevert, D-A

2006-01-01

To investigate the dynamic value of contrast medium-enhanced ultrasonography with Optison for appraisal of the vascularization of hepatic tumors using harmonic imaging, 3D-/power Doppler and B-flow. 60 patients with a mean age of 56 years (range 35-76 years) with 93 liver tumors, including histopathologically proven hepatocellular carcinoma (HCC) [15 cases with 20 lesions], liver metastases of colorectal tumors [17 cases with 33 lesions], metastases of breast cancer [10 cases with 21 lesions] and hemangiomas [10 cases with 19 lesions] were prospectively investigated by means of multislice CT as well as native and contrast medium-enhanced ultrasound using a multifrequency transducer (2.5-4 MHz, Logig 9, GE). B scan was performed with additional color and power Doppler, followed by a bolus injection of 0.5 ml Optison. Tumor vascularization was evaluated with coded harmonic angio (CHA), pulse inversion imaging with power Doppler, 3D power Doppler and in the late phase (>5 min) with B-flow. In 15 cases with HCC, i.a. DSA was performed in addition. The results were also correlated with MRT and histological findings. Compared to spiral-CT/MRT, only 72/93 (77%) of the lesions could be detected in the B scan, 75/93 (81%) with CHA and 93/93 (100%) in the pulse inversion mode. Tumor vascularization was detectable in 43/93 (46%) of lesions with native power Doppler, in 75/93 (81%) of lesions after administering contrast medium in the CHA mode, in 81/93 (87%) of lesions in the pulse inversion mode with power Doppler and in 77/93 (83%) of lesions with contrast-enhanced B-flow. Early arterial and capillary perfusion was best detected with CHA, particularly in 20/20 (100%) of the HCC lesions, allowing a 3D reconstruction. 3D power Doppler was especially useful in investigating the tumor margins. Up to 20 min after contrast medium injection, B-flow was capable of detecting increased metastatic tumor vascularization in 42/54 (78%) of cases and intratumoral perfusion in 17/20 (85

Risk of ultrasound-detected neonatal brain abnormalities in intrauterine growth-restricted fetuses born between 28 and 34 weeks' gestation: relationship with gestational age at birth and fetal Doppler parameters.

PubMed

Cruz-Martinez, R; Tenorio, V; Padilla, N; Crispi, F; Figueras, F; Gratacos, E

2015-10-01

To estimate the value of gestational age at birth and fetal Doppler parameters in predicting the risk of neonatal cranial abnormalities in intrauterine growth-restricted (IUGR) fetuses born between 28 and 34 weeks' gestation. Fetal Doppler parameters including umbilical artery (UA), middle cerebral artery (MCA), aortic isthmus, ductus venosus and myocardial performance index were evaluated in a cohort of 90 IUGR fetuses with abnormal UA Doppler delivered between 28 and 34 weeks' gestation and in 90 control fetuses matched for gestational age. The value of gestational age at birth and fetal Doppler parameters in predicting the risk of ultrasound-detected cranial abnormalities (CUA), including intraventricular hemorrhage, periventricular leukomalacia and basal ganglia lesions, was analyzed. Overall, IUGR fetuses showed a significantly higher incidence of CUA than did control fetuses (40.0% vs 12.2%, respectively; P < 0.001). Within the IUGR group, all predictive variables were associated individually with the risk of CUA, but fetal Doppler parameters rather than gestational age at birth were identified as the best predictor. MCA Doppler distinguished two groups with different degrees of risk of CUA (48.5% vs 13.6%, respectively; P < 0.01). In the subgroup with MCA vasodilation, presence of aortic isthmus retrograde net blood flow, compared to antegrade flow, allowed identification of a subgroup of cases with the highest risk of CUA (66.7% vs 38.6%, respectively; P < 0.05). Evaluation of fetal Doppler parameters, rather than gestational age at birth, allows identification of IUGR preterm fetuses at risk of neonatal brain abnormalities. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

The Pathophysiology of Decompression Sickness and the Effects of Doppler Detectable Bubbles.

DTIC Science & Technology

1980-12-18

Doppler Ultrasound and a calibrated 6 1 Venous Gas Embol i Scale. C. Electronic Counting of Doppler Bubble Signals 72 £ III. Pulmonary Embolism Studies...IA. Background 75 B. Right Ventricular Systolic Pressure following Gas 81 Embolization and Venous Gas Phase Content IC. Effects of Pulmonary Gas... Embolism on the Development 9 of Limb-Bend Decompression Sickness 1 IV. Gas Phase Formation in Highly Perfused Tissues IA. Renal 9 B. Cerebral 9 1 I I V

Power Doppler Ultrasound Evaluation of Peripheral Joint, Entheses, Tendon, and Bursa Abnormalities in Psoriatic Patients: A Clinical Study.

PubMed

Tang, Yuanjiao; Yang, Yujia; Xiang, Xi; Wang, Liyun; Zhang, Lingyan; Qiu, Li

2018-06-01

To evaluate the prevalence rates of peripheral joint, enthesis, tendon, and bursa abnormalities by power Doppler (PD) ultrasonic examination in patients with psoriatic arthritis (PsA), psoriatic patients without clinical signs of arthritis (non-PsA psoriasis group), and healthy individuals, to detect subclinical PsA. A total of 253 healthy volunteers, 242 non-PsA psoriatic patients, and 86 patients with PsA were assessed by 2-dimensional and power Doppler (PD) ultrasound. Peripheral joint, enthesis, tendon, and bursa abnormalities were observed, characterizing abnormal PD. The affected patients and sites with abnormalities in various ages were compared among groups; PD signal grades for the abnormalities were also compared. In the PsA group, significantly higher percentages of sites showing joint effusion/synovitis, enthesitis, and tenosynovitis in all age groups, and markedly higher rates of sites with bursitis were found in young and middle age groups, compared with the non-PsA and control groups (all p < 0.01). Meanwhile, the non-PsA group showed significantly higher rates of joint effusion/synovitis and enthesitis sites, and elevated PD signal grades of synovitis, enthesitis, and tenosynovitis in comparison with the control group, both in young and middle age groups (all p < 0.01). Patients with PsA have high percentages and PD signal grades of peripheral joint, tendon, enthesis, and bursa involvement. Young and middle-aged non-PsA patients have high synovitis and enthesitis percentages, and elevated PD signal grades of synovitis, enthesitis, and tenosynovitis.

Focused Ultrasound Surgery for Uterine Fibroids

MedlinePlus

... ultrasound surgery, your doctor may perform a pelvic magnetic resonance imaging (MRI) scan before treatment. Focused ultrasound surgery — also called magnetic resonance-guided focused ultrasound surgery or focused ultrasound ...

Ultrasound predictors of neonatal outcome in intrauterine growth restriction.

PubMed

Craigo, S D; Beach, M L; Harvey-Wilkes, K B; D'Alton, M E

1996-11-01

Our purpose was to assess the value of commonly performed ultrasound parameters in predicting neonatal outcome of fetuses with intrauterine growth restriction (IUGR). One hundred twenty-seven patients were identified on ultrasound examination to have IUGR. Estimated weight percentile, amniotic fluid volume, umbilical artery Doppler velocimetry, and head circumference/abdominal circumference ratio were compared with neonatal outcome. Thirty infants had severely adverse courses. The degree of growth restriction was strongly associated with adverse outcome and neonatal death. Umbilical artery Doppler waveforms with absent or reverse end-diastolic flow were predicted of neonatal death, bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC), and adverse outcome in general. Oligohydramnios was predictive of adverse outcome and neonatal death. Logistic regression also showed that absent or reverse end-diastolic flow and oligohydramnios were independent predictors of adverse outcome. Ultrasound findings of low estimated weight percentile, absent or reverse end-diastolic umbilical blood flow, and oligohydramnios are independent predictors of adverse neonatal outcome of growth restricted fetuses.

Power M-mode Doppler (PMD) for observing cerebral blood flow and tracking emboli.

PubMed

Moehring, Mark A; Spencer, Merrill P

2002-01-01

Difficulties in location of transcranial ultrasound (US) windows and blood flow in cerebral vessels, and unambiguous detection of microemboli, have limited expansion of transcranial Doppler US. We developed a new transcranial Doppler modality, power M-mode Doppler (PMD), for addressing these issues. A 2-MHz digital Doppler (Spencer Technologies TCD100M) having 33 sample gates placed with 2-mm spacing was configured to display Doppler signal power, colored red and blue for directionality, in an M-mode format. The spectrogram from a user-selected depth was displayed simultaneously. This system was then explored on healthy subjects and patients presenting with varying cerebrovascular pathology. PMD facilitated window location and alignment of the US beam to view blood flow from multiple vessels simultaneously, without sound or spectral clues. Microemboli appeared as characteristic sloping high-power tracks in the PMD image. Power M-mode Doppler is a new paradigm facilitating vessel location, diagnosis, monitoring and microembolus detection.

Comparison of optical and power Doppler ultrasound imaging for non-invasive evaluation of arsenic trioxide as a vascular disrupting agent in tumors.

PubMed

Alhasan, Mustafa K; Liu, Li; Lewis, Matthew A; Magnusson, Jennifer; Mason, Ralph P

2012-01-01

Small animal imaging provides diverse methods for evaluating tumor growth and acute response to therapy. This study compared the utility of non-invasive optical and ultrasound imaging to monitor growth of three diverse human tumor xenografts (brain U87-luc-mCherry, mammary MCF7-luc-mCherry, and prostate PC3-luc) growing in nude mice. Bioluminescence imaging (BLI), fluorescence imaging (FLI), and Power Doppler ultrasound (PD US) were then applied to examine acute vascular disruption following administration of arsenic trioxide (ATO).During initial tumor growth, strong correlations were found between manual caliper measured tumor volume and FLI intensity, BLI intensity following luciferin injection, and traditional B-mode US. Administration of ATO to established U87 tumors caused significant vascular shutdown within 2 hrs at all doses in the range 5 to 10 mg/kg in a dose dependant manner, as revealed by depressed bioluminescent light emission. At lower doses substantial recovery was seen within 4 hrs. At 8 mg/kg there was >85% reduction in tumor vascular perfusion, which remained depressed after 6 hrs, but showed some recovery after 24 hrs. Similar response was observed in MCF7 and PC3 tumors. Dynamic BLI and PD US each showed similar duration and percent reductions in tumor blood flow, but FLI showed no significant changes during the first 24 hrs.The results provide further evidence for comparable utility of optical and ultrasound imaging for monitoring tumor growth, More specifically, they confirm the utility of BLI and ultrasound imaging as facile assays of the vascular disruption in solid tumors based on ATO as a model agent.

Laser Doppler flowmetry, transcutaneous oxygen tension measurements and Doppler pressure compared in patients undergoing amputation.

PubMed

Lantsberg, L; Goldman, M

1991-04-01

The level of amputation continues to present a challenge for surgeons. In view of this, 24 patients who required an amputation of their ischaemic leg were studied prospectively using Laser Doppler flowmetry (LDF), TcpO2 measurements and Doppler ultrasound to assess the best level for amputation. In all patients gangrene of the leg and rest pain were the indication for an amputation. Skin oxygen tension (TcpO2) and skin blood flow (LDF) measurements were obtained the day before surgery on the proposed anterior and posterior skin flaps for below knee amputation and the maximum Doppler systolic pressure was measured. The level of amputation was chosen at surgery by clinical judgement without reference to the measurements mentioned above. A below knee amputation was performed in 17 patients and an above knee in seven. All amputations healed by primary intention. Doppler pressures showed poor discrimination with a median value of 10 mmHg (0-25) in AK patients and 35 mmHg (0-85) in the BK group (p greater than 0.05). In contrast TcpO2 showed a trend. In the BK group the median value was 20 mmHg (4-50) on the anterior and 22 mmHg (2-60) on the posterior flap compared to above knee amputees with median values of 6 mmHg (2-11) and 8 mmHg (3-38), respectively (p greater than 0.05). Laser Doppler seemed more useful. In BK patients the median LDF values were 36 mV (20-85) on the anterior and 34 mV (20-80) on the posterior flap with median LDF values of 10 mV (10-18) on the anterior and 11 mV (8-38) on the posterior flap in the above knee group (p less than 0.01). Laser Doppler flowmetry is a simple objective test, which is a better discriminator of skin flap perfusion than either TcpO2 or Doppler ankle pressures.

Three-dimensional ultrasound imaging of the prostate

NASA Astrophysics Data System (ADS)

Fenster, Aaron; Downey, Donal B.

1999-05-01

Ultrasonography, a widely used imaging modality for the diagnosis and staging of many diseases, is an important cost- effective technique, however, technical improvements are necessary to realize its full potential. Two-dimensional viewing of 3D anatomy, using conventional ultrasonography, limits our ability to quantify and visualize most diseases, causing, in part, the reported variability in diagnosis and ultrasound guided therapy and surgery. This occurs because conventional ultrasound images are 2D, yet the anatomy is 3D; hence the diagnostician must integrate multiple images in his mind. This practice is inefficient, and may lead to operator variability and incorrect diagnoses. In addition, the 2D ultrasound image represents a single thin plane at some arbitrary angle in the body. It is difficult to localize and reproduce the image plane subsequently, making conventional ultrasonography unsatisfactory for follow-up studies and for monitoring therapy. Our efforts have focused on overcoming these deficiencies by developing 3D ultrasound imaging techniques that can acquire B-mode, color Doppler and power Doppler images. An inexpensive desktop computer is used to reconstruct the information in 3D, and then is also used for interactive viewing of the 3D images. We have used 3D ultrasound images for the diagnosis of prostate cancer, carotid disease, breast cancer and liver disease and for applications in obstetrics and gynecology. In addition, we have also used 3D ultrasonography for image-guided minimally invasive therapeutic applications of the prostate such as cryotherapy and brachytherapy.

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.

Transvaginal ultrasound (image)

MedlinePlus

Transvaginal ultrasound is a method of imaging the genital tract in females. A hand held probe is inserted directly ... vaginal cavity to scan the pelvic structures, while ultrasound pictures are viewed on a monitor. The test ...

[Evaluation of neonatal prognosis using Doppler velocimeter in cases of a high risk fetus].

PubMed

Ferchiou-Cherif, M; Zhioua, F; Hafsia, S; Hamdoun, L; Jedoui, A; Slim, R; Meriah, S

1993-01-01

The authors describe the main characteristics of the Doppler method in the early diagnosis of chronic fetal distress, and report their personal results in the study of 51 high risk pregnancies. In their study the fetal doppler ultrasound findings were correlated with birth weight related to gestational age, and neonatal morbidity. The parameters established from the doppler ultrasound assessment were the placenta resistance (calculated from the formula of Pourcelot: R = S-D/S applied to the umbilical artery) and the cerebro-placental index, Rp/Rc, Rc being the index of cerebral arterial resistance. The diagnosis performance of the method appeared very good: the Rp index was found to be highly specific for hypotrophy (85,7%) and for neonatal morbidity (90%), the RCP index adding its own good sensitivity (85% for hypotrophy and 83,3% for neonatal morbidity). The authors conclude upon the interest to study simultaneously the fetal umbilical and cerebral arterial circulations. The pathological significance of the two indexes appears different so that they are to be complementary in the evaluation of fetal distress.

[Doppler echocardiography of tricuspid insufficiency. Methods of quantification].

PubMed

Loubeyre, C; Tribouilloy, C; Adam, M C; Mirode, A; Trojette, F; Lesbre, J P

1994-01-01

Evaluation of tricuspid incompetence has benefitted considerably from the development of Doppler ultrasound. In addition to direct analysis of the valves, which provides information about the mechanism involved, this method is able to provide an accurate evaluation, mainly through use of the Doppler mode. In addition to new criteria being evaluated (mainly the convergence zone of the regurgitant jet), some indices are recognised as good quantitative parameters: extension of the regurgitant jet into the right atrium, anterograde tricuspid flow, laminar nature of the regurgitant flow, analysis of the flow in the supra-hepatic veins, this is only semi-quantitative, since the calculation of the regurgitation fraction from the pulsed Doppler does not seem to be reliable; This accurate semi-quantitative evaluation is made possible by careful and consistent use of all the criteria available. The authors set out to discuss the value of the various evaluation criteria mentioned in the literature and try to define a practical approach.

[Parenchymal complications of the transplanted kidney: the role of color-Doppler imaging].

PubMed

Granata, Antonio; Clementi, Silvia; Clementi, Anna; Di Pietro, Fabio; Scarfia, Viviana R; Insalaco, Monica; Aucella, Filippo; Prencipe, Michele; Fiorini, Fulvio; Sicurezza, Elvia

2012-01-01

Kidney transplantation is the treatment of choice for end-stage renal disease, given the better quality of life of transplanted patients when compared to patients on maintenance dialysis. In spite of surgical improvements and new immunosuppressive regimens, part of the 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 ultrasound is low both in case of acute complications such as acute tubular necrosis, drug 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 including tissue pulsatility index, maximal fractional area and contrast-enhanced ultrasound increase the diagnostic power of ultrasonography in case of parenchymal complications of the transplanted kidney.

Christian Andreas Doppler--the man and his legacy.

PubMed

Coman, I M

2005-01-01

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

Evaluation of diagnostic value of CT scan, physical examination and ultrasound based on pathological findings in patients with pelvic masses.

PubMed

Firoozabadi, Razieh Dehghani; Karimi Zarchi, Mojgan; Mansurian, Hamid Reza; Moghadam, Bita Rafiei; Teimoori, Soraya; Naseri, Ali

2011-01-01

Because benign and malignant cervical and ovarian masses occur with different percentages in different age groups, the importance of primary diagnosis and selection of a suitable surgical procedure is underlined. Diagnosis of pelvic masses is carried out using ultrasound, physical examination, CT scan and MRI. The objective of this study is to evaluate the diagnostic value of CT scan in pelvic masses in comparison with physical examination-ultrasound based on pathology of the lesion in patients undergoing laparotomic surgery. This analytic-descriptive study focused on age, sonographic findings, physical examinations, CT scan and pathological findings in 139 patients with pelvic mass, gathered with questionnaires and statistically analayzed using the SPSS software programme. Of 139 patients with pelvic mass (patients aged from 17 to 75 years old), 62 (44%) cases were diagnosed as benign and 77 (55.4%) as malignant; among them malignant tratoma serocyst adenocarsinoma with 33 (23.7%) cases and benign myoma with 21 (15.2%) cases comprised the most frequent cases. The sensitivity and specificity of sonography-physical examination were 51.9% and 87.9% respectively and the sensitivity and specificity of CT scan images were 79.2% and 91.6% respectively. It was shown that CT scan images were more consistant with pathological findings in predicting appropriate surgical procedures than do sonography-physical examinations. The sensitivity of CT scan is far higher than that of sonography-physical examination in the diagnosis of pelvic mass malignancy.

Software For Clear-Air Doppler-Radar Display

NASA Technical Reports Server (NTRS)

Johnston, Bruce W.

1990-01-01

System of software developed to present plan-position-indicator scans of clear-air Doppler radar station on color graphical cathode-ray-tube display. Designed to incorporate latest accepted standards for equipment, computer programs, and meteorological data bases. Includes use of Ada programming language, of "Graphical-Kernel-System-like" graphics interface, and of Common Doppler Radar Exchange Format. Features include portability and maintainability. Use of Ada software packages produced number of software modules reused on other related projects.

Non-invasive transcranial ultrasound therapy based on a 3D CT scan: protocol validation and in vitro results

NASA Astrophysics Data System (ADS)

Marquet, F.; Pernot, M.; Aubry, J.-F.; Montaldo, G.; Marsac, L.; Tanter, M.; Fink, M.

2009-05-01

A non-invasive protocol for transcranial brain tissue ablation with ultrasound is studied and validated in vitro. The skull induces strong aberrations both in phase and in amplitude, resulting in a severe degradation of the beam shape. Adaptive corrections of the distortions induced by the skull bone are performed using a previous 3D computational tomography scan acquisition (CT) of the skull bone structure. These CT scan data are used as entry parameters in a FDTD (finite differences time domain) simulation of the full wave propagation equation. A numerical computation is used to deduce the impulse response relating the targeted location and the ultrasound therapeutic array, thus providing a virtual time-reversal mirror. This impulse response is then time-reversed and transmitted experimentally by a therapeutic array positioned exactly in the same referential frame as the one used during CT scan acquisitions. In vitro experiments are conducted on monkey and human skull specimens using an array of 300 transmit elements working at a central frequency of 1 MHz. These experiments show a precise refocusing of the ultrasonic beam at the targeted location with a positioning error lower than 0.7 mm. The complete validation of this transcranial adaptive focusing procedure paves the way to in vivo animal and human transcranial HIFU investigations.

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.

Ultrasound Biomicroscopy in Small Animal Research: Applications in Molecular and Preclinical Imaging

PubMed Central

Greco, A.; Mancini, M.; Gargiulo, S.; Gramanzini, M.; Claudio, P. P.; Brunetti, A.; Salvatore, M.

2012-01-01

Ultrasound biomicroscopy (UBM) is a noninvasive multimodality technique that allows high-resolution imaging in mice. It is affordable, widely available, and portable. When it is coupled to Doppler ultrasound with color and power Doppler, it can be used to quantify blood flow and to image microcirculation as well as the response of tumor blood supply to cancer therapy. Target contrast ultrasound combines ultrasound with novel molecular targeted contrast agent to assess biological processes at molecular level. UBM is useful to investigate the growth and differentiation of tumors as well as to detect early molecular expression of cancer-related biomarkers in vivo and to monitor the effects of cancer therapies. It can be also used to visualize the embryological development of mice in uterus or to examine their cardiovascular development. The availability of real-time imaging of mice anatomy allows performing aspiration procedures under ultrasound guidance as well as the microinjection of cells, viruses, or other agents into precise locations. This paper will describe some basic principles of high-resolution imaging equipment, and the most important applications in molecular and preclinical imaging in small animal research. PMID:22163379

Focused ultrasound: concept for automated transcutaneous control of hemorrhage in austere settings.

PubMed

Kucewicz, John C; Bailey, Michael R; Kaczkowski, Peter J; Carter, Stephen J

2009-04-01

High intensity focused ultrasound (HIFU) is being developed for a range of clinical applications. Of particular interest to NASA and the military is the use of HIFU for traumatic injuries because HIFU has the unique ability to transcutaneously stop bleeding. Automation of this technology would make possible its use in remote, austere settings by personnel not specialized in medical ultrasound. Here a system to automatically detect and target bleeding is tested and reported. The system uses Doppler ultrasound images from a clinical ultrasound scanner for bleeding detection and hardware for HIFU therapy. The system was tested using a moving string to simulate blood flow and targeting was visualized by Schlieren imaging to show the focusing of the HIFU acoustic waves. When instructed by the operator, a Doppler ultrasound image is acquired and processed to detect and localize the moving string, and the focus of the HIFU array is electronically adjusted to target the string. Precise and accurate targeting was verified in the Schlieren images. An automated system to detect and target simulated bleeding has been built and tested. The system could be combined with existing algorithms to detect, target, and treat clinical bleeding.

Ultrasound in twin pregnancies.

PubMed

Morin, Lucie; Lim, Kenneth

2011-06-01

and normal assessment. (III) 2. There are insufficient data to recommend a routine preterm labour surveillance protocol in terms of frequency, timing, and optimal cervical length thresholds. (II-2) 3. Singleton growth curves currently provide the best predictors of adverse outcome in twins and may be used for evaluating growth abnormalities. (III) 4. It is suggested that growth discordance be defined using either a difference (20 mm) in absolute measurement in abdominal circumference or a difference of 20% in ultrasound-derived estimated fetal weight. (II-2) 5. Although there is insufficient evidence to recommend a specific schedule for ultrasound assessment of twin gestation, most experts recommend serial ultrasound assessment every 2 to 3 weeks, starting at 16 weeks of gestation for monochorionic pregnancies and every 3 to 4 weeks, starting from the anatomy scan (18 to 22 weeks) for dichorionic pregnancies. (II-1) 6. Umbilical artery Doppler may be useful in the surveillance of twin gestations when there are complications involving the placental circulation or fetal hemodynamic physiology. (II-2) 7. Although many methods of evaluating the level of amniotic fluid in twins (deepest vertical pocket, single pocket, amniotic fluid index) have been described, there is not enough evidence to suggest that one method is more predictive than the others of adverse pregnancy outcome. (II-3) 8. Referral to an appropriate high-risk pregnancy centre is indicated when complications unique to twins are suspected on ultrasound. (II-2) These complications include: 1. Twin-to-twin transfusion syndrome 2. Monoamniotic twins gestation 3. Conjoined twins 4. Twin reversed arterial perfusion sequence 5. Single fetal death in the second or third trimester 6. Growth discordance in monochorionic twins. Recommendations 1. All patients who are suspected to have a twin pregnancy on first trimester physical examination or who are at risk (e.g., pregnancies resulting from assisted reproductive

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.

High-frequency ultrasound Doppler system for biomedical applications with a 30-MHz linear array.

PubMed

Xu, Xiaochen; Sun, Lei; Cannata, Jonathan M; Yen, Jesse T; Shung, K Kirk

2008-04-01

In this paper, we report the development of the first high-frequency (HF) pulsed-wave Doppler system using a 30-MHz linear array transducer to assess the cardiovascular functions in small animals. This array-based pulsed-wave Doppler system included a 16-channel HF analog beamformer, a HF pulsed-wave Doppler module, timing circuits, HF bipolar pulsers and analog front ends. The beamformed echoes acquired by the 16-channel analog beamformer were fed directly to the HF pulsed-wave Doppler module. Then the in-phase and quadrature-phase (IQ) audio Doppler signals were digitized by either a sound card or a Gage digitizer and stored in a personal computer. The Doppler spectrogram was displayed on a personal computer in real time. The two-way beamwidths were determined to be 160 microm to 320 microm when the array was electronically focused at different focal points at depths from 5 to 10 mm. A micro-flow phantom, consisting of a polyimide tube with an inner diameter of 127 microm and the wire phantom were used to evaluate and calibrate the system. The results show that the system is capable of detecting motion velocity of the wire phantom as low as 0.1 mm/s, and detecting blood-mimicking flow velocity in the 127-microm tube lower than 7 mm/s. The system was subsequently used to measure the blood flow in vivo in two mouse abdominal superficial vessels, with diameters of approximately 200 microm, and a mouse aorta close to the heart. These results demonstrated that this system may become an indispensable part of the current HF array-based imaging systems for small animal studies.

Tumour Vascular Shutdown and Cell Death Following Ultrasound-Microbubble Enhanced Radiation Therapy

PubMed Central

El Kaffas, Ahmed; Gangeh, Mehrdad J.; Farhat, Golnaz; Tran, William Tyler; Hashim, Amr; Giles, Anoja; Czarnota, Gregory J.

2018-01-01

High-dose radiotherapy effects are regulated by acute tumour endothelial cell death followed by rapid tumour cell death instead of canonical DNA break damage. Pre-treatment with ultrasound-stimulated microbubbles (USMB) has enabled higher-dose radiation effects with conventional radiation doses. This study aimed to confirm acute and longitudinal relationships between vascular shutdown and tumour cell death following radiation and USMB in a wild type murine fibrosarcoma model using in vivo imaging. Methods: Tumour xenografts were treated with single radiation doses of 2 or 8 Gy alone, or in combination with low-/high-concentration USMB. Vascular changes and tumour cell death were evaluated at 3, 24 and 72 h following therapy, using high-frequency 3D power Doppler and quantitative ultrasound spectroscopy (QUS) methods, respectively. Staining using in situ end labelling (ISEL) and cluster of differentiation 31 (CD31) of tumour sections were used to assess cell death and vascular distributions, respectively, as gold standard histological methods. Results: Results indicated a decrease in the power Doppler signal of up to 50%, and an increase of more than 5 dBr in cell-death linked QUS parameters at 24 h for tumours treated with combined USMB and radiotherapy. Power Doppler and quantitative ultrasound results were significantly correlated with CD31 and ISEL staining results (p < 0.05), respectively. Moreover, a relationship was found between ultrasound power Doppler and QUS results, as well as between micro-vascular densities (CD31) and the percentage of cell death (ISEL) (R2 0.5-0.9). Conclusions: This study demonstrated, for the first time, the link between acute vascular shutdown and acute tumour cell death using in vivo longitudinal imaging, contributing to the development of theoretical models that incorporate vascular effects in radiation therapy. Overall, this study paves the way for theranostic use of ultrasound in radiation oncology as a diagnostic modality to

Immersion ultrasonography: simultaneous A-scan and B-scan.

PubMed

Coleman, D J; Dallow, R L; Smith, M E

1979-01-01

In eyes with opaque media, ophthalmic ultrasound provides a unique source of information that can dramatically affect the course of patient management. In addition, when an ocular abnormality can be visualized, ultrasonography provides information that supplements and complements other diagnostic testing. It provides documentation and differentiation of abnormal states, such as vitreous hemorrhage and intraocular tumor, as well as differentiation of orbital tumors from inflammatory causes of exophthalmos. Additional capabilities of ultrasound are biometric determinations for calculation of intraocular lens implant powers and drug-effectiveness studies. Maximal information is derived from ultrasonography when A-scan and B-scan techniques are employed simultaneously. Flexibility of electronics, variable-frequency transducers, and the use of several different manual scanning patterns aid in detection and interpretation of results. The immersion system of ultrasonography provides these features optimally.

Quantitative Doppler Analysis Using Conventional Color Flow Imaging Acquisitions.

PubMed

Karabiyik, Yucel; Ekroll, Ingvild Kinn; Eik-Nes, Sturla H; Lovstakken, Lasse

2018-05-01

Interleaved acquisitions used in conventional triplex mode result in a tradeoff between the frame rate and the quality of velocity estimates. On the other hand, workflow becomes inefficient when the user has to switch between different modes, and measurement variability is increased. This paper investigates the use of power spectral Capon estimator in quantitative Doppler analysis using data acquired with conventional color flow imaging (CFI) schemes. To preserve the number of samples used for velocity estimation, only spatial averaging was utilized, and clutter rejection was performed after spectral estimation. The resulting velocity spectra were evaluated in terms of spectral width using a recently proposed spectral envelope estimator. The spectral envelopes were also used for Doppler index calculations using in vivo and string phantom acquisitions. In vivo results demonstrated that the Capon estimator can provide spectral estimates with sufficient quality for quantitative analysis using packet-based CFI acquisitions. The calculated Doppler indices were similar to the values calculated using spectrograms estimated on a commercial ultrasound scanner.

The Role of Acoustic Cavitation in Ultrasound-triggered Drug Release from Echogenic Liposomes

NASA Astrophysics Data System (ADS)

Kopechek, Jonathan A.

Cardiovascular disease (CVD) is the leading cause of death in the United States and globally. CVD-related mortality, including coronary heart disease, heart failure, or stroke, generally occurs due to atherosclerosis, a condition in which plaques build up within arterial walls, potentially causing blockage or rupture. Targeted therapies are needed to achieve more effective treatments. Echogenic liposomes (ELIP), which consist of a lipid membrane surrounding an aqueous core, have been developed to encapsulate a therapeutic agent and/or gas bubbles for targeted delivery and ultrasound image enhancement. Under certain conditions ultrasound can cause nonlinear bubble growth and collapse, known as "cavitation." Cavitation activity has been associated with enhanced drug delivery across cellular membranes. However, the mechanisms of ultrasound-mediated drug release from ELIP have not been previously investigated. Thus, the objective of this dissertation is to elucidate the role of acoustic cavitation in ultrasound-mediated drug release from ELIP. To determine the acoustic and physical properties of ELIP, the frequency-dependent attenuation and backscatter coefficients were measured between 3 and 30 MHz. The results were compared to a theoretical model by measuring the ELIP size distribution in order to determine properties of the lipid membrane. It was found that ELIP have a broad size distribution and can provide enhanced ultrasound image contrast across a broad range of clinically-relevant frequencies. Calcein, a hydrophilic fluorescent dye, and papaverine, a lipophilic vasodilator, were separately encapsulated in ELIP and exposed to color Doppler ultrasound pulses from a clinical diagnostic ultrasound scanner in a flow system. Spectrophotometric techniques (fluorescence and absorbance measurements) were used to detect calcein or papaverine release. As a positive control, Triton X-100 (a non-ionic detergent) was added to ELIP samples not exposed to ultrasound in order

Real-time 3-dimensional contrast-enhanced ultrasound in detecting hemorrhage of blunt renal trauma.

PubMed

Xu, Rui-Xue; Li, Ye-Kuo; Li, Ting; Wang, Sha-Sha; Yuan, Gui-Zhong; Zhou, Qun-Fang; Zheng, Hai-Rong; Yan, Fei

2013-10-01

The objective of this study is to evaluate the diagnostic value of real-time 3-dimensional contrast-enhanced ultrasound in the hemorrhage of blunt renal trauma. Eighteen healthy New Zealand white rabbits were randomly divided into 3 groups. Blunt renal trauma was performed on each group by using minitype striker. Ultrasonography, color Doppler flow imaging, and contrast-enhanced 2-dimensional and real-time 3-dimensional ultrasound were applied before and after the strike. The time to shock and blood pressure were subjected to statistical analysis. Then, a comparative study of ultrasound and pathology was carried out. All the struck kidneys were traumatic. In the ultrasonography, free fluid was found under the renal capsule. In the color Doppler flow imaging, active hemorrhage was not identified. In 2-dimensional contrast-enhanced ultrasound, active hemorrhage of the damaged kidney was characterized. Real-time 3-dimensional contrast-enhanced ultrasound showed a real-time and stereoscopic ongoing bleeding of the injured kidney. The wider the hemorrhage area in 4-dimensional contrast-enhanced ultrasound was, the faster the blood pressure decreased. Real-time 3-dimensional contrast-enhanced ultrasound is a promising noninvasive tool for stereoscopically and vividly detecting ongoing hemorrhage of blunt renal trauma in real time. © 2013.

Doppler signals observed during high temperature thermal ablation are the result of boiling.

PubMed

Nahirnyak, Volodymyr M; Moros, Eduardo G; Novák, Petr; Suzanne Klimberg, V; Shafirstein, Gal

2010-01-01

To elucidate the causation mechanism of Spectral Doppler ultrasound signals (DUS) observed during high temperature thermal ablation and evaluate their potential for image-guidance. Sixteen ex vivo ablations were performed in fresh turkey breast muscle, eight with radiofrequency ablation (RFA) devices, and eight with a conductive interstitial thermal therapy (CITT) device. Temperature changes in the ablation zone were measured with thermocouples located at 1 to 10 mm away from the ablation probes. Concomitantly, DUS were recorded using a standard diagnostic ultrasound scanner. Retrospectively, sustained observations of DUS were correlated with measured temperatures. Sustained DUS was arbitrarily defined as the Doppler signals lasting more than 10 s as observed in the diagnostic ultrasound videos captured from the scanner. For RFA experiments, minimum average temperature (T1 +/- SD) at which sustained DUS were observed was 97.2 +/- 7.3 degrees C, while the maximum average temperature (T2 +/- SD) at which DUS were not seen was 74.3 +/- 9.1 degrees C. For CITT ablation, T1 and T2 were 95.7 +/- 5.9 degrees C and 91.6 +/- 7.2 degrees C, respectively. It was also observed, especially during CITT ablation, that temperatures remained relatively constant during Doppler activity. The value of T1 was near the standard boiling point of water (99.61 degrees C) while T2 was below it. Together, T1 and T2 support the conclusion that DUS during high temperature thermal ablation are the result of boiling (phase change). This conclusion is also supported by the nearly constant temperature histories maintained at locations from which DUS emanated.

Effects of acetazolamide on the micro- and macro-vascular cerebral hemodynamics: a diffuse optical and transcranial doppler ultrasound study

PubMed Central

Zirak, Peyman; Delgado-Mederos, Raquel; Martí-Fàbregas, Joan; Durduran, Turgut

2010-01-01

Acetazolamide (ACZ) was used to stimulate the cerebral vasculature on ten healthy volunteers to assess the cerebral vasomotor reactivity (CVR). We have combined near infrared spectroscopy (NIRS), diffuse correlation spectroscopy (DCS) and transcranial Doppler (TCD) technologies to non-invasively assess CVR in real-time by measuring oxy- and deoxy-hemoglobin concentrations, using NIRS, local cerebral blood flow (CBF), using DCS, and blood flow velocity (CBFV) in the middle cerebral artery, using TCD. Robust and persistent increases in oxy-hemoglobin concentration, CBF and CBFV were observed. A significant agreement was found between macro-vascular (TCD) and micro-vascular (DCS) hemodynamics, between the NIRS and TCD data, and also within NIRS and DCS results. The relative cerebral metabolic rate of oxygen, rCMRO2, was also determined, and no significant change was observed. Our results showed that the combined diffuse optics-ultrasound technique is viable to follow (CVR) and rCMRO2 changes in adults, continuously, at the bed-side and in real time. PMID:21258561

Effects of acetazolamide on the micro- and macro-vascular cerebral hemodynamics: a diffuse optical and transcranial doppler ultrasound study.

PubMed

Zirak, Peyman; Delgado-Mederos, Raquel; Martí-Fàbregas, Joan; Durduran, Turgut

2010-11-19

Acetazolamide (ACZ) was used to stimulate the cerebral vasculature on ten healthy volunteers to assess the cerebral vasomotor reactivity (CVR). We have combined near infrared spectroscopy (NIRS), diffuse correlation spectroscopy (DCS) and transcranial Doppler (TCD) technologies to non-invasively assess CVR in real-time by measuring oxy- and deoxy-hemoglobin concentrations, using NIRS, local cerebral blood flow (CBF), using DCS, and blood flow velocity (CBFV) in the middle cerebral artery, using TCD. Robust and persistent increases in oxy-hemoglobin concentration, CBF and CBFV were observed. A significant agreement was found between macro-vascular (TCD) and micro-vascular (DCS) hemodynamics, between the NIRS and TCD data, and also within NIRS and DCS results. The relative cerebral metabolic rate of oxygen, rCMRO(2), was also determined, and no significant change was observed. Our results showed that the combined diffuse optics-ultrasound technique is viable to follow (CVR) and rCMRO(2) changes in adults, continuously, at the bed-side and in real time.

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

MicroV Technology to Improve Transcranial Color Coded Doppler Examinations.

PubMed

Malferrari, Giovanni; Pulito, Giuseppe; Pizzini, Attilia Maria; Carraro, Nicola; Meneghetti, Giorgio; Sanzaro, Enzo; Prati, Patrizio; Siniscalchi, Antonio; Monaco, Daniela

2018-05-04

The purpose of this review is to provide an update on technology related to Transcranial Color Coded Doppler Examinations. Microvascularization (MicroV) is an emerging Power Doppler technology which can allow visualization of low and weak blood flows even at high depths, thus providing a suitable technique for transcranial ultrasound analysis. With MicroV, reconstruction of the vessel shape can be improved, without any overestimation. Furthermore, by analyzing the Doppler signal, MicroV allows a global image of the Circle of Willis. Transcranial Doppler was originally developed for the velocimetric analysis of intracranial vessels, in particular to detect stenoses and the assessment of collateral circulation. Doppler velocimetric analysis was then compared to other neuroimaging techniques, thus providing a cut-off threshold. Transcranial Color Coded Doppler sonography allowed the characterization of vessel morphology. In both Color Doppler and Power Doppler, the signal overestimated the shape of the intracranial vessels, mostly in the presence of thin vessels and high depths of study. In further neurosonology technology development efforts, attempts have been made to address morphology issues and overcome technical limitations. The use of contrast agents has helped in this regard by introducing harmonics and subtraction software, which allowed better morphological studies of vessels, due to their increased signal-to-noise ratio. Having no limitations in the learning curve, in time and contrast agent techniques, and due to its high signal-to-noise ratio, MicroV has shown great potential to obtain the best morphological definition. Copyright © 2018 by the American Society of Neuroimaging.

Lung ultrasound in the critically ill.

PubMed

Lichtenstein, Daniel A

2014-01-09

), many disciplines (pulmonology, cardiology…), austere countries, and a help in any procedure (thoracentesis). A 1992, cost-effective gray-scale unit, without Doppler, and a microconvex probe are efficient. Lung ultrasound is a holistic discipline for many reasons (e.g., one probe, perfect for the lung, is able to scan the whole-body). Its integration can provide a new definition of priorities. The BLUE-protocol and FALLS-protocol allow simplification of expert echocardiography, a clear advantage when correct cardiac windows are missing.

Determining Directions of Ultrasound in Solids

NASA Technical Reports Server (NTRS)

Generazio, Edward R.; Roth, Don J.

1987-01-01

Ultrasound shadows cast by grooves. Improved method for determining direction of ultrasound in materials is shadow method using Scanning laser acoustic microscopy (SLAM). Direction of ultrasound calculated from dimensions of groove and portion of surface groove shields from ultrasound. Method has variety of applications in nontraditional quality-control applications.

Detection and characterization of Budd-Chiari syndrome with inferior vena cava obstruction: Comparison of fixed and flexible delayed scan time of computed tomography venography.

PubMed

Zhou, Peng-Li; Wu, Gang; Han, Xin-Wei; Bi, Yong-Hua; Zhang, Wen-Guang; Wu, Zheng-Yang

2017-06-01

To compare the results of computed tomography venography (CTV) with a fixed and a flexible delayed scan time for Budd-Chiari syndrome (BCS) with inferior vena cava (IVC) obstruction. A total of 209 consecutive BCS patients with IVC obstruction underwent either a CTV with a fixed delayed scan time of 180s (n=87) or a flexible delayed scan time for good image quality according to IVC blood flow in color Doppler ultrasonography (n=122). The IVC blood flow velocity was measured using a color Doppler ultrasound prior to CT scan. Image quality was classified as either good, moderate, or poor. Image quality, surrounding structures and the morphology of the IVC obstruction were compared between the two groups using a χ 2 -test or paired or unpaired t-tests as appropriate. Inter-observer agreement was assessed using Kappa statistics. There was no significant difference in IVC blood flow velocity between the two groups. Overall image quality, surrounding structures and IVC obstruction morphology delineation on the flexible delayed scan time of CTV images were rated better relative to those obtained by fixed delayed scan time of CTV images (p<0.001). Evaluation of CTV data sets was significantly facilitated with flexible delayed scan time of CTV. There were no significant differences in Kappa statistics between Group A and Group B. The flexible delayed scan time of CTV was associated with better detection and more reliable characterization of BCS with IVC obstruction compared to a fixed delayed scan time. Copyright © 2017 Elsevier B.V. All rights reserved.

Cerebral Lateralization and General Intelligence: Gender Differences in a Transcranial Doppler Study

ERIC Educational Resources Information Center

Njemanze, P.C.

2005-01-01

The present study evaluated cerebral lateralization during Raven's progressive matrices (RPM) paradigm in female and male subjects. Bilateral simultaneous transcranial Doppler (TCD) ultrasound was used to measure mean blood flow velocities (MBFV) in the right and left middle cerebral arteries (MCAs) in 24 (15 females and 9 males) right-handed…

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.

Role of ultrasonography with color-Doppler in the emergency diagnosis of acute penile fracture: a case report.

PubMed

Buyukkaya, Ramazan; Buyukkaya, Ayla; Ozturk, Beyhan; Kayıkçı, Ali; Yazgan, Ömer

2014-03-01

Penile fracture is the rupture of tunica albuginea, typically resulting from blunt trauma, intercourse, or penile manipulation. Diagnosis is made clinically. Ultrasound is not used frequently in diagnosis of penile fracture but it provides a fast, non-invasive alternative to more often used MRI and cavernography. We aimed to present diagnostic ultrasound and color Doppler images of a patient with acute penile fracture in conjunction with literature.

Calculation of Left Ventricular Diastolic Time Constant (TAU) in Dogs with Mitral Regurgitation Using Continuous-Wave Doppler.

PubMed

Wen, Chaoyang; Sun, Jing; Fan, Chunzhi; Dou, Jianping

2018-05-04

The left ventricular diastolic time constant (Tau) cannot be practically measured non-invasively. Thus, the aim of this study was to investigate a new method for the evaluation of Tau using continuous-wave (CW) Doppler in dogs with mitral regurgitation. Guided by ultrasound, we created 12 beagle models of mitral regurgitation and acute ischemic left ventricular diastolic dysfunction. Raw audio signals of the CW Doppler spectra were collected, and new mitral regurgitation Doppler spectra were observed after computer re-processing. The new Doppler spectra contour line was constructed using MATLAB (Version R2009), and two time intervals, t1-t2 and t1-t3, were measured on the descending branch of the mitral regurgitation Doppler spectrum and were substituted into Bai's equation group. The Doppler-derived Tau (Tau-d) was resolved and compared with the simultaneous catheter-derived Tau (Tau-c). No significant difference (p > 0.05) between Tau-d (49.33 ± 18.79 ms) and Tau-c (48.76 ± 17.60 ms) was found. A correlation analysis between Tau-d and Tau-c suggested a strong positive relationship (r = 0.85, p = 0.000). Bland-Altman plots of Tau-d and Tau-c revealed fair agreement. Compared with previous non-invasive approaches, this method is simpler and more accurate. There is a strong positive relationship and fair agreement between Tau-d and Tau-c. Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.

Imaging shear wave propagation for elastic measurement using OCT Doppler variance method

NASA Astrophysics Data System (ADS)

Zhu, Jiang; Miao, Yusi; Qu, Yueqiao; Ma, Teng; Li, Rui; Du, Yongzhao; Huang, Shenghai; Shung, K. Kirk; Zhou, Qifa; Chen, Zhongping

2016-03-01

In this study, we have developed an acoustic radiation force orthogonal excitation optical coherence elastography (ARFOE-OCE) method for the visualization of the shear wave and the calculation of the shear modulus based on the OCT Doppler variance method. The vibration perpendicular to the OCT detection direction is induced by the remote acoustic radiation force (ARF) and the shear wave propagating along the OCT beam is visualized by the OCT M-scan. The homogeneous agar phantom and two-layer agar phantom are measured using the ARFOE-OCE system. The results show that the ARFOE-OCE system has the ability to measure the shear modulus beyond the OCT imaging depth. The OCT Doppler variance method, instead of the OCT Doppler phase method, is used for vibration detection without the need of high phase stability and phase wrapping correction. An M-scan instead of the B-scan for the visualization of the shear wave also simplifies the data processing.

Characterising the effect of a variety of surface roughness on boundary layer wind and dynamics within the scanning Doppler lidar network in Finland

NASA Astrophysics Data System (ADS)

Hirsikko, Anne; O'Connor, Ewan J.; Wood, Curtis R.; Vakkari, Ville

2013-04-01

Aerosol particle and trace gas atmospheric content is controlled by natural and anthropological emissions. However, further dispersion in the atmosphere is driven by wind and dynamic mixing. Atmospheric surface and boundary layer dynamics have direct and indirect effects on weather, air quality and processes affecting climate (e.g. gas exchange between ecosystem and atmosphere). In addition to the amount of solar energy and prevailing meteorological condition, the surface topography has a strong influence on the close to surface wind field and turbulence, particularly in urban areas (e.g. Barlow and Coceal, 2009). In order to characterise the effect of forest, urban and coastal surfaces on boundary layer wind and mixing, we have utilised the Finnish Doppler lidar network (Hirsikko et al., 2013). The network consists of five 1.5 μm Doppler lidars (HALO Photonics, Pearson et al., 2009), of which four are capable of full hemispheric scanning and are located at Helsinki (60.12°N, 25.58°E, 45 m asl.), Utö island (59.47°N, 21.23°E, 8 m asl.), SMEAR II at Hyytiälä (61.50°N, 24.17°E, 181 m asl.) and Kuopio (62.44°N, 27.32°E, 190 m asl.). The fifth lidar at Sodankylä (67.37°N, 26.63°E, 171 m asl.) is a new model designed for the Arctic environment with no external moving parts, but still retains limited scan capability. Investigation of boundary layer wind and mixing condition can now be extended beyond vertical profiles of horizontal wind, and dissipation rate of turbulent kinetic energy (O'Connor et al., 2010) throughout the boundary layer. We have applied custom designed scanning routines for 3D-observation of the wind fields and simultaneous aerosol particle distribution continuously for over one year at Helsinki and Utö, and began similar scanning routines at Kuopio and Hyytiälä in spring 2013. In this long term project, our aims are to 1) characterise the effect of the land-sea interface and the urban environment on the wind and its turbulent nature

Breast ultrasound tomography with two parallel transducer arrays

NASA Astrophysics Data System (ADS)

Huang, Lianjie; Shin, Junseob; Chen, Ting; Lin, Youzuo; Gao, Kai; Intrator, Miranda; Hanson, Kenneth

2016-03-01

Breast ultrasound tomography is an emerging imaging modality to reconstruct the sound speed, density, and ultrasound attenuation of the breast in addition to ultrasound reflection/beamforming images for breast cancer detection and characterization. We recently designed and manufactured a new synthetic-aperture breast ultrasound tomography prototype with two parallel transducer arrays consisting of a total of 768 transducer elements. The transducer arrays are translated vertically to scan the breast in a warm water tank from the chest wall/axillary region to the nipple region to acquire ultrasound transmission and reflection data for whole-breast ultrasound tomography imaging. The distance of these two ultrasound transducer arrays is adjustable for scanning breasts with different sizes. We use our breast ultrasound tomography prototype to acquire phantom and in vivo patient ultrasound data to study its feasibility for breast imaging. We apply our recently developed ultrasound imaging and tomography algorithms to ultrasound data acquired using our breast ultrasound tomography system. Our in vivo patient imaging results demonstrate that our breast ultrasound tomography can detect breast lesions shown on clinical ultrasound and mammographic images.

Analysis of achilles tendon vascularity with second-generation contrast-enhanced ultrasound.

PubMed

Genovese, Eugenio; Ronga, Mario; Recaldini, Chiara; Fontana, Federico; Callegari, Leonardo; Maffulli, Nicola; Fugazzola, Carlo

2011-01-01

To compare morphological, power Doppler, and contrast-enhanced ultrasound (CEUS) features of the Achilles tendon between asymptomatic athletes and athletes who had undergone surgical repair of a previous rupture. Twenty-four athletes were divided in two groups (A and B). Group A included 14 patients with a median age of 32 years (range 27 to 47 years) who had undergone surgical repair for unilateral Achilles tendon rupture. Group B (control group) included 10 subjects with a median age of 34 years (range 27 to 40 years) with no previous or present history of tendinopathy. All patients were evaluated with ultrasound, power Doppler, and CEUS with second-generation contrast agent. We studied the uninjured Achilles tendon in athletes of group A and either the left or the right Achilles tendon of the athletes in group B. CEUS showed a significantly greater ability to detect a greater number of vascular spots within the uninjured tendon of group A compared to group B (<0.05). In athletes who had suffered a tear of an Achilles tendon, CEUS detected small vessels that were not identified by power Doppler ultrasound in the uninjured contralateral Achilles tendon. CEUS is useful to evaluate vascularity not detected by other imaging techniques. Vascularity in the uninjured tendon seems to be increased in patients who had a previous rupture. Copyright © 2011 Wiley Periodicals, Inc.

Ultrafast Ultrasound Imaging of Ocular Anatomy and Blood Flow

PubMed Central

Urs, Raksha; Ketterling, Jeffrey A.; Silverman, Ronald H.

2016-01-01

Purpose Ophthalmic ultrasound imaging is currently performed with mechanically scanned single-element probes. These probes have limited capabilities overall and lack the ability to image blood flow. Linear-array systems are able to detect blood flow, but these systems exceed ophthalmic acoustic intensity safety guidelines. Our aim was to implement and evaluate a new linear-array–based technology, compound coherent plane-wave ultrasound, which offers ultrafast imaging and depiction of blood flow at safe acoustic intensity levels. Methods We compared acoustic intensity generated by a 128-element, 18-MHz linear array operated in conventionally focused and plane-wave modes and characterized signal-to-noise ratio (SNR) and lateral resolution. We developed plane-wave B-mode, real-time color-flow, and high-resolution depiction of slow flow in postprocessed data collected continuously at a rate of 20,000 frames/s. We acquired in vivo images of the posterior pole of the eye by compounding plane-wave images acquired over ±10° and produced images depicting orbital and choroidal blood flow. Results With the array operated conventionally, Doppler modes exceeded Food and Drug Administration safety guidelines, but plane-wave modalities were well within guidelines. Plane-wave data allowed generation of high-quality compound B-mode images, with SNR increasing with the number of compounded frames. Real-time color-flow Doppler readily visualized orbital blood flow. Postprocessing of continuously acquired data blocks of 1.6-second duration allowed high-resolution depiction of orbital and choroidal flow over the cardiac cycle. Conclusions Newly developed high-frequency linear arrays in combination with plane-wave techniques present opportunities for the evaluation of ocular anatomy and blood flow, as well as visualization and analysis of other transient phenomena such as vessel wall motion over the cardiac cycle and saccade-induced vitreous motion. PMID:27428169

[The specific features of Doppler ultrasound study of ophthalmic vessels in young persons with peripheral vitreochorioretinal dystrophies].

PubMed

Pozdeeva, O G

2005-01-01

Hemodynamic parameters were studied in the ophthalmic artery, short posterior ciliary arteries (SPCA), long posterior ciliary arteries (LPCA), and central artery of the retina (CAR). Doppler ultrasound study (DUSS) was performed on an Acuson Aspen multipurpose diagnostic system using a linear transducer at a frequency of 7.5 MHz in the pulse mode. Chelyabinsk students aged 17-25 years were examined. A number of specific features of retinal blood supply were detected in young persons with dystrophic diseases of the periphery of the fundus oculi. These included decreased blood flow velocities and less systolic flow acceleration time in SPCA, LPCA, and CAR in peripheral vitreochorioretinal dystrophies (PVCRD). The higher pulsatile index (PI) in the LPCA system characterized a possible mechanism responsible for compensation of impaired blood supply in the retinal periphery in the development of PVCRD. The high values of the pulsatile index and the vascular wall resistivity index in CAR reflected the changes determining the absence of complications as retinal ruptures and detachment. There were neither changes in ophthalmic arterial blood flow depending on the type of PVCRD and the nature of its course nor significant differences in blood supply to the eye in different types of refraction.

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.

Dual-frequency ultrasound imaging and therapeutic bilaminar array using frequency selective isolation layer.

PubMed

Azuma, Takashi; Ogihara, Makoto; Kubota, Jun; Sasaki, Akira; Umemura, Shin-ichiro; Furuhata, Hiroshi

2010-05-01

A new ultrasound array transducer with two different optimal frequencies designed for diagnosis and therapy integration in Doppler imaging-based transcranial sonothrombolysis is described. Previous studies have shown that respective frequencies around 0.5 and 2 MHz are suitable for sonothrombolysis and Doppler imaging. Because of the small acoustic window available for transcranial ultrasound exposure, it is highly desirable that both therapeutic and diagnostic ultrasounds pass through the same aperture with high efficiency. To achieve such a dual-frequency array transducer, we propose a bilaminar array, having an array for imaging and another for therapy, with a frequency selective isolation layer between the two arrays. The function of this layer is to isolate the imaging array from the therapy array at 2 MHz without disturbing the 0.5-MHz ultrasound transmission. In this study, we first used a 1-D model including two lead zirconate titanate (PZT) layers separated by an isolation layer for intuitive understanding of the phenomena. After that, we optimized the acoustic impedance and thickness of the isolation layer by analyzing pulse propagation in a 2-D model by conducting a numerical simulation with commercially available software. The optimal acoustic impedance and thickness are 3 to 4 MRayI and lambda/10, respectively. On the basis of the optimization, a prototype array transducer was fabricated, and the spatial resolutions of the Doppler images it obtained were found to be practically the same as those obtained through conventional imaging array transducers.

Prospective cohort study of ultrasound-ultrasound and ultrasound-MR enterography agreement in the evaluation of pediatric small bowel Crohn disease.

PubMed

Dillman, Jonathan R; Smith, Ethan A; Sanchez, Ramon; DiPietro, Michael A; Dehkordy, Soudabeh Fazeli; Adler, Jeremy; DeMatos-Maillard, Vera; Khalatbari, Shokoufeh; Davenport, Matthew S

2016-04-01

There is a paucity of published literature describing ultrasound (US)-US and US-MR enterography (MRE) inter-radiologist agreement in pediatric small bowel Crohn disease. To prospectively assess US-US and US-MRE inter-radiologist agreement in pediatric small bowel Crohn disease. Institutional Review Board approval and informed consent/assent were obtained for this HIPAA-compliant prospective cohort study of children with newly diagnosed distal small bowel Crohn disease (July 2012 to December 2014). Enrolled subjects (n = 29) underwent two small bowel US examinations performed by blinded independent radiologists both before and at multiple time points after initiation of medical therapy (231 unique US examinations, in total); 134 US examinations were associated with concurrent MRE. The MRE examination was interpreted by a third blinded radiologist. The following was documented on each examination: involved length of ileum (cm); maximum bowel wall thickness (mm); amount of bowel wall and mesenteric Doppler signal, and presence of stricture, penetrating disease and/or abscess. Inter-radiologist agreement was assessed with single-measure, three-way, mixed-model intra-class correlation coefficients (ICC) and prevalence-adjusted, bias-adjusted kappa statistics (κ). Numbers in brackets are 95% confidence intervals. Ultrasound-US agreement was moderate for involved length (ICC: 0.41 [0.35-0.49]); substantial for maximum bowel wall thickness (ICC: 0.67 [0.64-0.70]); moderate for bowel wall Doppler signal (ICC: 0.53 [0.48-0.59]); slight for mesenteric Doppler signal (ICC: 0.25 [0.18-0.42]), and moderate to almost perfect for stricture (κ: 0.54), penetrating disease (κ: 0.80), and abscess (κ: 0.96). US-MRE agreement was moderate for involved length (ICC: 0.42 [0.37-0.49]); substantial for maximum bowel wall thickness (ICC: 0.66 [0.65-0.69]), and substantial to almost perfect for stricture (κ: 0.61), penetrating disease (κ: 0.72) and abscess (κ: 0.88). Ultrasound

Coronary CT Angiography Incorporating Doppler-Guided Prospective ECG Gating in Patients with High Heart Rate: Comparison with Results of Traditional Prospective ECG Gating

PubMed Central

Li, Min; Yu, Bing-bing; Wu, Jian-hua; Xu, Lin; Sun, Gang

2013-01-01

Purpose As Doppler ultrasound has been proven to be an effective tool to predict and compress the optimal pulsing windows, we evaluated the effective dose and diagnostic accuracy of coronary CT angiography (CTA) incorporating Doppler-guided prospective electrocardiograph (ECG) gating, which presets pulsing windows according to Doppler analysis, in patients with a heart rate >65 bpm. Materials and Methods 119 patients with a heart rate >65 bpm who were scheduled for invasive coronary angiography were prospectively studied, and patients were randomly divided into traditional prospective (n = 61) and Doppler-guided prospective (n = 58) ECG gating groups. The exposure window of traditional prospective ECG gating was set at 30%–80% of the cardiac cycle. For the Doppler group, the length of diastasis was analyzed by Doppler. For lengths greater than 90 ms, the pulsing window was preset during diastole (during 60%–80%); otherwise, the optimal pulsing intervals were moved from diastole to systole (during 30%–50%). Results The mean heart rates of the traditional ECG and the Doppler-guided group during CT scanning were 75.0±7.7 bpm (range, 66–96 bpm) and 76.5±5.4 bpm (range: 66–105 bpm), respectively. The results indicated that whereas the image quality showed no significant difference between the traditional and Doppler groups (P = 0.42), the radiation dose of the Doppler group was significantly lower than that of the traditional group (5.2±3.4mSv vs. 9.3±4.5mSv, P<0.001). The sensitivities of CTA applying traditional and Doppler-guided prospective ECG gating to diagnose stenosis on a segment level were 95.5% and 94.3%, respectively; specificities 98.0% and 97.1%, respectively; positive predictive values 90.7% and 88.2%, respectively; negative predictive values 99.0% and 98.7%, respectively. There was no statistical difference in concordance between the traditional and Doppler groups (P = 0.22). Conclusion Doppler-guided prospective ECG gating

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.

B-Mode ultrasound pose recovery via surgical fiducial segmentation and tracking

NASA Astrophysics Data System (ADS)

Asoni, Alessandro; Ketcha, Michael; Kuo, Nathanael; Chen, Lei; Boctor, Emad; Coon, Devin; Prince, Jerry L.

2015-03-01

Ultrasound Doppler imaging may be used to detect blood clots after surgery, a common problem. However, this requires consistent probe positioning over multiple time instances and therefore significant sonographic expertise. Analysis of ultrasound B-mode images of a fiducial implanted at the surgical site offers a landmark to guide a user to the same location repeatedly. We demonstrate that such an implanted fiducial may be successfully detected and tracked to calculate pose and guide a clinician consistently to the site of surgery, potentially reducing the ultrasound experience required for point of care monitoring.

[Liver ultrasound: focal lesions and diffuse diseases].

PubMed

Segura Grau, A; Valero López, I; Díaz Rodríguez, N; Segura Cabral, J M

2016-01-01

Liver ultrasound is frequently used as a first-line technique for the detection and characterization of the most common liver lesions, especially those incidentally found focal liver lesions, and for monitoring of chronic liver diseases. Ultrasound is not only used in the Bmode, but also with Doppler and, more recently, contrast-enhanced ultrasound. It is mainly used in the diagnosis of diffuse liver diseases, such as steatosis or cirrhosis. This article presents a practical approach for diagnosis workup, in which the different characteristics of the main focal liver lesions and diffuse liver diseases are reviewed. Copyright © 2014 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España, S.L.U. All rights reserved.

[Per partum acidosis: Interest and feasibility of cerebral Doppler during labor].

PubMed

Barrois, M; Chartier, M; Lecarpentier, E; Goffinet, F; Tsatsaris, V

2016-09-01

To evaluate feasibility and interest of fetal cerebral Doppler during labor and the link with fetal pH to predict perinatal fetal asphyxia. Our prospective study in a university perinatal center, included patients during labor. There were no risk factors during pregnancy and patients were included after 37 weeks of pregnancy. For each patient an ultrasound with cerebral Doppler was done concomitant to a fetal scalp blood sample. We collected maternal and fetal characteristics as well as cervix dilatation, fetal heart rate analysis and fetal presentation. Among 49 patients included over a period of 4 months, cerebral Doppler failed in 7 cases (11%). Majority of failure occurred at 10cm of dilatation (P=0.007, OR=14.1 [1.483; 709.1275]). Others factors like: maternal age, body mass index, parity, history of C-Section were not associated with higher rate of failure. We did not found either significant correlation between cerebral fetal Doppler and pH on fetal scalp blood sample (r=0.15) nor pH at cord blood sample (r=0.13). No threshold of cerebral Doppler is significant for fetal asphyxia prediction. Fetal cerebral Doppler is feasible during labor with a low rate of failure but not a good exam to predict fetal acidosis and asphyxia. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Laser Doppler technology applied to atmospheric environmental operating problems

NASA Technical Reports Server (NTRS)

Weaver, E. A.; Bilbro, J. W.; Dunkin, J. A.; Jeffreys, H. B.

1976-01-01

Carbon dioxide laser Doppler ground wind data were very favorably compared with data from standard anemometers. As a result of these measurements, two breadboard systems were developed for taking research data: a continuous wave velocimeter and a pulsed Doppler system. The scanning continuous wave laser Doppler velocimeter developed for detecting, tracking and measuring aircraft wake vortices was successfully tested at an airport where it located vortices to an accuracy of 3 meters at a range of 150 meters. The airborne pulsed laser Doppler system was developed to detect and measure clear air turbulence (CAT). This system was tested aboard an aircraft, but jet stream CAT was not encountered. However, low altitude turbulence in cumulus clouds near a mountain range was detected by the system and encountered by the aircraft at the predicted time.

Role of ultrasound in colorectal diseases.

PubMed

Bor, Renáta; Fábián, Anna; Szepes, Zoltán

2016-11-21

Ultrasound is an undervalued non-invasive examination in the diagnosis of colonic diseases. It has been replaced by the considerably more expensive magnetic resonance imaging and computed tomography, despite the fact that, as first examination, it can usefully supplement the diagnostic process. Transabdominal ultrasound can provide quick information about bowel status and help in the choice of adequate further examinations and treatment. Ultrasonography, as a screening imaging modality in asymptomatic patients can identify several colonic diseases such as diverticulosis, inflammatory bowel disease or cancer. In addition, it is widely available, cheap, non-invasive technique without the use of ionizing radiation, therefore it is safe to use in childhood or during pregnancy, and can be repeated at any time. New ultrasound techniques such as elastography, contrast enhanced and Doppler ultrasound, mini-probes rectal and transperineal ultrasonography have broadened the indication. It gives an overview of the methodology of various ultrasound examinations, presents the morphology of normal bowel wall and the typical changes in different colonic diseases. We will pay particular attention to rectal and transperineal ultrasound because of their outstanding significance in the diagnosis of rectal and perineal disorders. This article seeks to overview the diagnostic impact and correct indications of bowel ultrasound.

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.

The prediction of radiofrequency ablation zone volume using vascular indices of 3-dimensional volumetric colour Doppler ultrasound in an in vitro blood-perfused bovine liver model

PubMed Central

Lanctot, Anthony C; McCarter, Martin D; Roberts, Katherine M; Glueck, Deborah H; Dodd, Gerald D

2017-01-01

Objective: To determine the most reliable predictor of radiofrequency (RF) ablation zone volume among three-dimensional (3D) volumetric colour Doppler vascular indices in an in vitro blood-perfused bovine liver model. Methods: 3D colour Doppler volume data of the local hepatic parenchyma were acquired from 37 areas of 13 bovine livers connected to an in vitro oxygenated blood perfusion system. Doppler vascular indices of vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were obtained from the volume data using 3D volume analysis software. 37 RF ablations were performed at the same locations where the ultrasound data were obtained from. The relationship of these vascular indices and the ablation zone volumes measured from gross specimens were analyzed using a general linear mixed model fit with random effect for liver and backward stepwise regression analysis. Results: FI was significantly associated with ablation zone volumes measured on gross specimens (p = 0.0047), but explained little of the variance (Rβ2 = 0.21). Ablation zone volume decreased by 0.23 cm3 (95% confidence interval: −0.38, −0.08) for every 1 increase in FI. Neither VI nor VFI was significantly associated with ablation zone volumes (p > 0.05). Conclusion: Although FI was associated with ablation zone volumes, it could not sufficiently explain their variability, limiting its clinical applicability. VI, FI and VFI are not clinically useful in the prediction of RF ablation zone volume in the liver. Advances in knowledge: Despite a significant association of FI with ablation zone volumes, VI, FI and VFI cannot be used for their prediction. Different Doppler vascular indices need to be investigated for clinical use. PMID:27925468

Development of a Methodology for the Characterisation of Air-coupled Ultrasound Probes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pietroni, Paolo; Marco Revel, Gian

2010-05-28

This study is aimed at developing a technique for the characterisation of air-coupled ultrasound probes, starting from the analysis of the mechanical behaviour of the probe membrane. The vibratory behaviour of the emission membrane is studied using laser-Doppler vibrometry techniques with high frequency demodulation system (20 MHz). The determination of the vibration provides information which are useful for the assessment of the performance of the probe, in particular concerning the Quality factor and the portion of the membrane which really contributes to the emission. During the second step the results of the vibration measurements are used to calculate, by meansmore » of numerical boundary element method, the ultrasound beam emitted in terms of intensity in space. The obtained field is compared with the direct measurements carried out by scanning with the receiver probe and a pinhole plate. This comparison allows the potential and the problems of the two different characterisation techniques to be determined, even if the pinhole technique (which is currently considered the state of the art) cannot be used as an absolute reference. This study appears to be useful for paving the way for a new methodology for the calibration of air-coupled ultrasound probes, which potentially could be used not only to improve the probe manufacturing process, but also to control conformity to specifications.« less

Development of a Methodology for the Characterisation of Air-coupled Ultrasound Probes

NASA Astrophysics Data System (ADS)

Pietroni, Paolo; Marco Revel, Gian

2010-05-01

This study is aimed at developing a technique for the characterisation of air-coupled ultrasound probes, starting from the analysis of the mechanical behaviour of the probe membrane. The vibratory behaviour of the emission membrane is studied using laser-Doppler vibrometry techniques with high frequency demodulation system (20 MHz). The determination of the vibration provides information which are useful for the assessment of the performance of the probe, in particular concerning the Quality factor and the portion of the membrane which really contributes to the emission. During the second step the results of the vibration measurements are used to calculate, by means of numerical boundary element method, the ultrasound beam emitted in terms of intensity in space. The obtained field is compared with the direct measurements carried out by scanning with the receiver probe and a pinhole plate. This comparison allows the potential and the problems of the two different characterisation techniques to be determined, even if the pinhole technique (which is currently considered the state of the art) cannot be used as an absolute reference. This study appears to be useful for paving the way for a new methodology for the calibration of air-coupled ultrasound probes, which potentially could be used not only to improve the probe manufacturing process, but also to control conformity to specifications.

Automatic extraction of disease-specific features from Doppler images

NASA Astrophysics Data System (ADS)

Negahdar, Mohammadreza; Moradi, Mehdi; Parajuli, Nripesh; Syeda-Mahmood, Tanveer

2017-03-01

Flow Doppler imaging is widely used by clinicians to detect diseases of the valves. In particular, continuous wave (CW) Doppler mode scan is routinely done during echocardiography and shows Doppler signal traces over multiple heart cycles. Traditionally, echocardiographers have manually traced such velocity envelopes to extract measurements such as decay time and pressure gradient which are then matched to normal and abnormal values based on clinical guidelines. In this paper, we present a fully automatic approach to deriving these measurements for aortic stenosis retrospectively from echocardiography videos. Comparison of our method with measurements made by echocardiographers shows large agreement as well as identification of new cases missed by echocardiographers.

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

Validation of a basic neurosonology laboratory for detecting cervical carotid artery stenosis.

PubMed

de la Cruz Cosme, C; Dawid Milner, M S; Ojeda Burgos, G; Gallardo Tur, A; Márquez Martínez, M; Segura, T

2017-03-24

Most of the cases of ischaemic stroke in our setting are of atherothrombotic origin. Detecting intracranial and cervical carotid artery stenosis in patients with ischaemic stroke is therefore essential. Ultrasonography has become the tool of choice for diagnosing carotid artery stenosis because it is both readily accessibility and reliable. However, use of this technique must be validated in each laboratory. The purpose of this study is to validate Doppler ultrasound in our laboratory as a means of detecting severe carotid artery stenosis. We conducted an observational descriptive study to evaluate diagnostic tests. The results from transcranial and cervical carotid Doppler ultrasound scans conducted by neurologists were compared to those from carotid duplex scans performed by radiologists in patients diagnosed with stroke. Arteriography was considered the gold standard (MR angiography, CT angiography, or conventional arteriography). Our sample included 228 patients. Transcranial and cervical carotid Doppler ultrasound showed a sensitivity of 95% and specificity of 100% for detection of carotid artery stenosis > 70%, whereas carotid duplex displayed a sensitivity of 87% and a specificity of 94%. Transcranial carotid Doppler ultrasound achieved a sensitivity of 78% and a specificity of 98% for detection of intracranial stenosis. Doppler ultrasound in our neurosonology laboratory was found to be a useful diagnostic tool for detecting cervical carotid artery stenosis and demonstrated superiority to carotid duplex despite the lack of B-mode. Furthermore, this technique was found to be useful for detecting intracranial stenosis. Copyright © 2017 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

Virtual guidance as a tool to obtain diagnostic ultrasound for spaceflight and remote environments.

PubMed

Martin, David S; Caine, Timothy L; Matz, Timothy; Lee, Stuart M C; Stenger, Michael B; Sargsyan, Ashot E; Platts, Steven H

2012-10-01

With missions planned to travel greater distances from Earth at ranges that make real-time two-way communication impractical, astronauts will be required to perform autonomous medical diagnostic procedures during future exploration missions. Virtual guidance is a form of just-in-time training developed to allow novice ultrasound operators to acquire diagnostically-adequate images of clinically relevant anatomical structures using a prerecorded audio/visual tutorial viewed in real-time. Individuals without previous experience in ultrasound were recruited to perform carotid artery (N = 10) and ophthalmic (N = 9) ultrasound examinations using virtual guidance as their only training tool. In the carotid group, each untrained operator acquired two-dimensional, pulsed and color Doppler of the carotid artery. In the ophthalmic group, operators acquired representative images of the anterior chamber of the eye, retina, optic nerve, and nerve sheath. Ultrasound image quality was evaluated by independent imaging experts. Of the studies, 8 of the 10 carotid and 17 of 18 of the ophthalmic images (2 images collected per study) were judged to be diagnostically adequate. The quality of all but one of the ophthalmic images ranged from adequate to excellent. Diagnostically-adequate carotid and ophthalmic ultrasound examinations can be obtained by previously untrained operators with assistance from only an audio/video tutorial viewed in real time while scanning. This form of just-in-time training, which can be applied to other examinations, represents an opportunity to acquire important information for NASA flight surgeons and researchers when trained medical personnel are not available or when remote guidance is impractical.

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

[Quantification and monitoring of vascular resistance in the lower limbs by the Doppler method (animal model)

NASA Technical Reports Server (NTRS)

Arbeille, P.; Berson, M.; Blondeau, B.; Durand, A.; Bodard, S.; Locatelli, A.; Fox, G. E. (Principal Investigator)

1995-01-01

The object of this study was to define and validate a non-invasive method of evaluation and monitoring of vascular resistances in the leg. Blood flow velocity was measured by Doppler ultrasound in an animal model (ewe) with similar blood flow characteristics in the lower limb as man and allowing access to the required invasive measurements for validation of the method (pressure and flow). Vascular resistances distal to the measuring point (femoral, for example) were assessed using the resistance index R = D/S, S being the peak systolic deflection and D that of diastolic reflux of the Doppler spectral analysis of flow in the femoral artery. The values and variations of this resistance index were compared with the vascular resistances calculated from measurements of pressure and flow at the point of Doppler sampling and expressed in mmHg/ml/min. Femoral flow was measured by Doppler ultrasound (Doppler-echo), and mean pressure by an arterial catheter introduced into the abdominal aorta. Compression of the lower limb veins induced a venous return resulting in a reduction of cardiac output and femoral flow. During compression, femoral flow decreased by an average of 29% (p < 0.001) although mean pressure and heart rate did not change significantly. The femoral resistance index (Rf) increased by an average of 37.5% (p < 0.01) and vascular resistances increased by 45.9% (p < 0.01). Injection of 1 mg adrenaline induced peripheral vasoconstriction with an increase in blood pressure and a decrease in heart rate and femoral flow.(ABSTRACT TRUNCATED AT 250 WORDS).

Ultrasound

MedlinePlus

... reflect off body structures. A computer receives the waves and uses them to create a picture. Unlike with an x-ray or CT scan, this test does not use ionizing radiation. The test is done in the ultrasound ...

Practical utility of thermodilution versus doppler ultrasound to measure hemodialysis blood access flow.

PubMed

Fontseré, Néstor; Mestres, Gaspar; Barrufet, Marta; Burrel, Marta; Vera, Manel; Arias, Marta; Masso, Elisabeth; Cases, Aleix; Maduell, Francisco; Campistol, Josep M

2013-01-01

The current clinical guidelines recommend indirect access blood flow (Qa) measurement as one of the most important components in vascular access maintenance programs. The best-know methods are doppler ultrasound (DU) and saline dilution method. This study evaluates the efficiency of Qa measurement with thermodilution method (TD) in comparison with the DU. Transversal study in 64 patients in hemodialysis (41 men); mean age 59.9 years with 54 AVFs and 10 PTFE. Qa reference value was obtained with DU in brachial artery (AVFs) or at the zone of arterial puncture (AVGs). Bland-Altman and interclass correlation coefficient (ICC) were used to study accuracy. Mean values obtained with DU-Qa were 1426 ± 753 mL/min AVFs and 1186 ± 789 mL/min AVGs. The mean Qa with TD was 1372 ± 770 AVFs (bias 54.6; ICC 0.923) and 1176 ± 758 AVGs (bias 10.2; ICC 0.992). In the subgroup of 28 patients with radiocephalic latero-terminal AVFs the DU-Qa was 1232 ± 767 mL/min. The Qa was in radial artery 942 (ICC 0.805); radial-ulnar artery 1103 (ICC 0.973); cephalic vein 788 (ICC 0.772) and TD 1026 (ICC 0.971). We detected 5 cases of significant stenosis. After endovascular treatment the Kt was 79 liters (61; p=0.043) and TD-Qa 895 mL/min (663; p=0.043). TD represents a good indirect method of Qa measurement. In the subgroup of patients with radiocephalic AVFs, Qa measurements in the radial and ulnar artery are more accurate. Therefore, in this situation the TD method obtained an excellent correlation in comparison to brachial artery.

Real-time high-velocity resolution color Doppler OCT

NASA Astrophysics Data System (ADS)

Westphal, Volker; Yazdanfar, Siavash; Rollins, Andrew M.; Izatt, Joseph A.

2001-05-01

Color Doppler optical coherence tomography (CDOCT), also called Optical Doppler Tomography) is a noninvasive optical imaging technique, which allows for micron-scale physiological flow mapping simultaneous with morphological OCT imaging. Current systems for real-time endoscopic optical coherence tomography (EOCT) would be enhanced by the capability to visualize sub-surface blood flow for applications in early cancer diagnosis and the management of bleeding ulcers. Unfortunately, previous implementations of CDOCT have either been sufficiently computationally expensive (employing Fourier or Hilbert transform techniques) to rule out real-time imaging of flow, or have been restricted to imaging of excessively high flow velocities when used in real time. We have developed a novel Doppler OCT signal-processing strategy capable of imaging physiological flow rates in real time. This strategy employs cross-correlation processing of sequential A-scans in an EOCT image, as opposed to autocorrelation processing as described previously. To measure Doppler shifts in the kHz range using this technique, it was necessary to stabilize the EOCT interferometer center frequency, eliminate parasitic phase noise, and to construct a digital cross correlation unit able to correlate signals of megahertz bandwidth by a fixed lag of up to a few ms. The performance of the color Doppler OCT system was demonstrated in a flow phantom, demonstrating a minimum detectable flow velocity of ~0.8 mm/s at a data acquisition rate of 8 images/second (with 480 A-scans/image) using a handheld probe. Dynamic flow as well as using it freehanded was shown. Flow was also detectable in a phantom in combination with a clinical usable endoscopic probe.

Imaging doppler lidar for wind turbine wake profiling

DOEpatents

Bossert, David J.

2015-11-19

An imaging Doppler lidar (IDL) enables the measurement of the velocity distribution of a large volume, in parallel, and at high spatial resolution in the wake of a wind turbine. Because the IDL is non-scanning, it can be orders of magnitude faster than conventional coherent lidar approaches. Scattering can be obtained from naturally occurring aerosol particles. Furthermore, the wind velocity can be measured directly from Doppler shifts of the laser light, so the measurement can be accomplished at large standoff and at wide fields-of-view.

Evaluating the risk of appendiceal perforation when using ultrasound as the initial diagnostic imaging modality in children with suspected appendicitis.

PubMed

Alerhand, Stephen; Meltzer, James; Tay, Ee Tein

2017-08-01

Ultrasound scan has gained attention for diagnosing appendicitis due to its avoidance of ionizing radiation. However, studies show that ultrasound scan carries inferior sensitivity to computed tomography scan. A non-diagnostic ultrasound scan could increase the time to diagnosis and appendicectomy, particularly if follow-up computed tomography scan is needed. Some studies suggest that delaying appendicectomy increases the risk of perforation. To investigate the risk of appendiceal perforation when using ultrasound scan as the initial diagnostic imaging modality in children with suspected appendicitis. We retrospectively reviewed 1411 charts of children ≤17 years old diagnosed with appendicitis at two urban academic medical centers. Patients who underwent ultrasound scan first were compared to those who underwent computed tomography scan first. In the sub-group analysis, patients who only received ultrasound scan were compared to those who received initial ultrasound scan followed by computed tomography scan. Main outcome measures were appendiceal perforation rate and time from triage to appendicectomy. In 720 children eligible for analysis, there was no significant difference in perforation rate between those who had initial ultrasound scan and those who had initial computed tomography scan (7.3% vs. 8.9%, p = 0.44), nor in those who had ultrasound scan only and those who had initial ultrasound scan followed by computed tomography scan (8.0% vs. 5.6%, p = 0.42). Those patients who had ultrasound scan first had a shorter triage-to-incision time than those who had computed tomography scan first (9.2 (IQR: 5.9, 14.0) vs. 10.2 (IQR: 7.3, 14.3) hours, p = 0.03), whereas those who had ultrasound scan followed by computed tomography scan took longer than those who had ultrasound scan only (7.8 (IQR: 5.3, 11.6) vs. 15.1 (IQR: 10.6, 20.6), p < 0.001). Children < 12 years old receiving ultrasound scan first had lower perforation rate (p = 0.01) and

Defining the ultrasound longitudinal natural history of newly diagnosed pediatric small bowel Crohn disease treated with infliximab and infliximab-azathioprine combination therapy.

PubMed

Dillman, Jonathan R; Dehkordy, Soudabeh Fazeli; Smith, Ethan A; DiPietro, Michael A; Sanchez, Ramon; DeMatos-Maillard, Vera; Adler, Jeremy; Zhang, Bin; Trout, Andrew T

2017-07-01

Little is known about changes in the imaging appearances of the bowel and mesentery over time in either pediatric or adult patients with newly diagnosed small bowel Crohn disease treated with anti-tumor necrosis factor-alpha (anti-TNF-α) therapy. To define how bowel ultrasound findings change over time and correlate with laboratory inflammatory markers in children who have been newly diagnosed with pediatric small bowel Crohn disease and treated with infliximab. We included 28 pediatric patients treated with infliximab for newly diagnosed ileal Crohn disease who underwent bowel sonography prior to medical therapy and at approximately 2 weeks, 1 month, 3 months and 6 months after treatment initiation; these patients also had laboratory testing at baseline, 1 month and 6 months. We used linear mixed models to compare mean results between visits and evaluate whether ultrasound measurements changed over time. We used Spearman rank correlation to assess bivariate relationships. Mean subject age was 15.3±2.2 years; 11 subjects were girls (39%). We observed decreases in mean length of disease involvement (12.0±5.4 vs. 9.1±5.3 cm, P=0.02), maximum bowel wall thickness (5.6±1.8 vs. 4.7±1.7 mm, P=0.02), bowel wall color Doppler signal (1.7±0.9 vs. 1.2±0.8, P=0.002) and mesenteric color Doppler signal (1.1±0.9 vs. 0.6±0.6, P=0.005) at approximately 2 weeks following the initiation of infliximab compared to baseline. All laboratory inflammatory markers decreased at 1 month (P-values<0.0001). There was strong correlation between bowel wall color Doppler signal and fecal calprotectin (ρ=0.710; P<0.0001). Linear mixed models confirmed that maximum bowel wall thickness (P=0.04), length of disease involvement (P=0.0002) and bowel wall color Doppler signal (P<0.0001) change over time in response to infliximab, when adjusted for age, sex, azathioprine therapy, scanning radiologist and baseline short pediatric Crohn's disease activity index score. The ultrasound

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

PubMed

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

2017-11-01

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

Neuromuscular ultrasound of cranial nerves.

PubMed

Tawfik, Eman A; Walker, Francis O; Cartwright, Michael S

2015-04-01

Ultrasound of cranial nerves is a novel subdomain of neuromuscular ultrasound (NMUS) which may provide additional value in the assessment of cranial nerves in different neuromuscular disorders. Whilst NMUS of peripheral nerves has been studied, NMUS of cranial nerves is considered in its initial stage of research, thus, there is a need to summarize the research results achieved to date. Detailed scanning protocols, which assist in mastery of the techniques, are briefly mentioned in the few reference textbooks available in the field. This review article focuses on ultrasound scanning techniques of the 4 accessible cranial nerves: optic, facial, vagus and spinal accessory nerves. The relevant literatures and potential future applications are discussed.

Office-based ultrasound screening for abdominal aortic aneurysm

PubMed Central

Blois, Beau

2012-01-01

Abstract Objective To assess the efficacy of an office-based, family physician–administered ultrasound examination to screen for abdominal aortic aneurysm (AAA). Design A prospective observational study. Consecutive patients were approached by nonphysician staff. Setting Rural family physician offices in Grand Forks and Revelstoke, BC. Participants The Canadian Society for Vascular Surgery screening recommendations for AAA were used to help select patients who were at risk of AAA. All men 65 years of age or older were included. Women 65 years of age or older were included if they were current smokers or had diabetes, hypertension, a history of coronary artery disease, or a family history of AAA. Main outcome measures A focused “quick screen,” which measured the maximal diameter of the abdominal aorta using point-of-care ultrasound technology, was performed in the office by a resident physician trained in emergency ultrasonography. Each patient was then booked for a criterion standard scan (ie, a conventional abdominal ultrasound scan performed by a technician and interpreted by a radiologist). The maximal abdominal aortic diameter measured by ultrasound in the office was compared with that measured by the criterion standard method. The time to screen each patient was recorded. Results Forty-five patients were included in data analysis; 62% of participants were men. The mean age was 73 years. The mean pairwise difference between the office-based ultrasound scan and the criterion standard scan was not statistically significant. The mean absolute difference between the 2 scans was 0.20 cm (95% CI 0.15 to 0.25 cm). Correlation between the scans was 0.81. The office-based ultrasound scan had both a sensitivity and a specificity of 100%. The mean time to screen each patient was 212 seconds (95% CI 194 to 230 seconds). Conclusion Abdominal aortic aneurysm screening can be safely performed in the office by family physicians who are trained to use point

Office-based ultrasound screening for abdominal aortic aneurysm.

PubMed

Blois, Beau

2012-03-01

To assess the efficacy of an office-based, family physician–administered ultrasound examination to screen for abdominal aortic aneurysm (AAA). A prospective observational study. Consecutive patients were approached by nonphysician staff. Rural family physician offices in Grand Forks and Revelstoke, BC. The Canadian Society for Vascular Surgery screening recommendations for AAA were used to help select patients who were at risk of AAA. All men 65 years of age or older were included. Women 65 years of age or older were included if they were current smokers or had diabetes, hypertension, a history of coronary artery disease, or a family history of AAA. A focused “quick screen”, which measured the maximal diameter of the abdominal aorta using point-of-care ultrasound technology, was performed in the office by a resident physician trained in emergency ultrasonography. Each patient was then booked for a criterion standard scan (i.e., a conventional abdominal ultrasound scan performed by a technician and interpreted by a radiologist). The maximal abdominal aortic diameter measured by ultrasound in the office was compared with that measured by the criterion standard method. The time to screen each patient was recorded. Forty-five patients were included in data analysis; 62% of participants were men. The mean age was 73 years. The mean pairwise difference between the office-based ultrasound scan and the criterion standard scan was not statistically significant. The mean absolute difference between the 2 scans was 0.20 cm (95% CI 0.15 to 0.25 cm). Correlation between the scans was 0.81. The office-based ultrasound scan had both a sensitivity and a specificity of 100%. The mean time to screen each patient was 212 seconds (95% CI 194 to 230 seconds). Abdominal aortic aneurysm screening can be safely performed in the office by family physicians who are trained to use point-of- care ultrasound technology. The screening test can be completed within the time constraints of a

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.

Lung ultrasound in the critically ill

PubMed Central

2014-01-01

in adults), many disciplines (pulmonology, cardiology…), austere countries, and a help in any procedure (thoracentesis). A 1992, cost-effective gray-scale unit, without Doppler, and a microconvex probe are efficient. Lung ultrasound is a holistic discipline for many reasons (e.g., one probe, perfect for the lung, is able to scan the whole-body). Its integration can provide a new definition of priorities. The BLUE-protocol and FALLS-protocol allow simplification of expert echocardiography, a clear advantage when correct cardiac windows are missing. PMID:24401163

Analysis of rhG-CSF-effects on platelets by in vitro bleeding test and transcranial Doppler ultrasound examination.

PubMed

Söhngen, D; Wienen, S; Siebler, M; Boogen, C; Scheid, C; Schulz, A; Kobbe, G; Diehl, V; Heyll, A

1998-12-01

Experimental evidence suggests a stimulatory effect of recombinant human granulocyte colony-stimulating factor (rhG-CSF) on both platelets and coagulation. RhG-CSF is increasingly used to stimulate healthy volunteer donors for blood stem cell mobilization. We therefore assessed 25 healthy donors receiving rhG-CSF for changes in in vitro bleeding test (IVBT), coagulation parameters and cerebral microembolism by transcranial Doppler (TCD) ultrasound. A significant shortening of IVBT was found on day 4 of rhG-CSF administration together with increased levels of fibrinogen and factor VIII and reduced activities of protein C and protein S. Although these changes are quite small it is possible that they may lead to a hypercoagulable state especially in donors with other risk factors for thromboembolism. However, TCD examination failed to detect any signs of microembolism. We therefore conclude that rhG-CSF leads to significant changes in coagulation parameters, but has no effect on TCD detectable microembolism as a stroke risk factor. However donors receiving rhG-CSF should be examined carefully to detect pre-existing changes in the coagulation system and we would like to suggest a routine thrombophilia screen.

Prognostic accuracy of cerebroplacental ratio and middle cerebral artery Doppler for adverse perinatal outcome: systematic review and meta‐analysis

PubMed Central

De Boer, M. A.; Heymans, M. W.; Schoonmade, L. J.; Bossuyt, P. M. M.; Mol, B. W. J.; De Groot, C. J. M.; Bax, C. J.

2018-01-01

than did UA Doppler in the prediction of low Apgar score (P = 0.017) and emergency delivery for fetal distress (P = 0.034). CPR outperformed MCA Doppler in the prediction of composite adverse outcome (P < 0.001) and emergency delivery for fetal distress (P = 0.013). Conclusion Calculating the CPR with MCA Doppler can add value to UA Doppler assessment in the prediction of adverse perinatal outcome in women with a singleton pregnancy. However, it is unclear to which subgroup of pregnant women this applies. The effectiveness of the CPR in guiding clinical management needs to be evaluated in clinical trials. © 2017 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology. PMID:28708272

Ultrasound scans and dual energy CT identify tendons as preferred anatomical location of MSU crystal depositions in gouty joints.

PubMed

Yuan, Yuan; Liu, Chang; Xiang, Xi; Yuan, Tong-Ling; Qiu, Li; Liu, Yi; Luo, Yu-Bin; Zhao, Y; Herrmann, Martin

2018-05-01

The present study was performed to localize the articular deposition of monosodium urate (MSU) crystal in joints. We compare the detection efficiencies of dual-energy CT (DECT) and ultrasound scans. Analyses by DECT and ultrasound were performed with 184 bilateral joints of the lower limbs of 54 consecutive gout patients. All joints were categorized into (1) knee, (2) ankle, (3) MTP1, and (4) MTP2, and sorted into those with and those without detectable MSU deposition. The comparison of the positive rate between DECT and ultrasound and the agreement was performed using the McNemar test and the Cohen's κ coefficient, respectively. Next, we listed the MSU crystal deposition as assessed by ultrasound between the DECT-positive and -negative joints according to their interior structure. We included tendons, synovia, cartilage, subcutaneous tissue, etc. RESULTS: Among all joints, the percentages with MSU crystal deposition detected by DECT (99/184, 53.8%) and ultrasound (106/184, 57.6%) were comparable (P = 0.530 > 0.05). For MTP1 (21/34, 61.8%; 12/34, 35.3%; P < 0.05) and MTP2-5 (17/34, 50.0%; 10/34, 29.4%, P < 0.05), ultrasound and DECT were more efficient, respectively. The data concordance in 46 of 50 joints (92.00%; κ = 0.769, P < 0.05) for knee; and 27 of 34 joints (79.41%; κ = 0.588, P < 0.05) for MTP2-5 and suggested that tendons were the most frequent anatomical location of MSU crystal deposition. The tendons are the most frequent anatomical location of MSU crystal depositions. The concordance rate of knee joints and MTP2-5 joints shows good agreement between DECT and ultrasound depending on the location.

Recent technological advancements in cardiac ultrasound imaging.

PubMed

Dave, Jaydev K; Mc Donald, Maureen E; Mehrotra, Praveen; Kohut, Andrew R; Eisenbrey, John R; Forsberg, Flemming

2018-03-01

About 92.1 million Americans suffer from at least one type of cardiovascular disease. Worldwide, cardiovascular diseases are the number one cause of death (about 31% of all global deaths). Recent technological advancements in cardiac ultrasound imaging are expected to aid in the clinical diagnosis of many cardiovascular diseases. This article provides an overview of such recent technological advancements, specifically focusing on tissue Doppler imaging, strain imaging, contrast echocardiography, 3D echocardiography, point-of-care echocardiography, 3D volumetric flow assessments, and elastography. With these advancements ultrasound imaging is rapidly changing the domain of cardiac imaging. The advantages offered by ultrasound imaging include real-time imaging, imaging at patient bed-side, cost-effectiveness and ionizing-radiation-free imaging. Along with these advantages, the steps taken towards standardization of ultrasound based quantitative markers, reviewed here, will play a major role in addressing the healthcare burden associated with cardiovascular diseases. Copyright © 2017 Elsevier B.V. All rights reserved.

The Multiple Doppler Radar Workshop, November 1979.

NASA Astrophysics Data System (ADS)

Carbone, R. E.; Harris, F. I.; Hildebrand, P. H.; Kropfli, R. A.; Miller, L. J.; Moninger, W.; Strauch, R. G.; Doviak, R. J.; Johnson, K. W.; Nelson, S. P.; Ray, P. S.; Gilet, M.

1980-10-01

The findings of the Multiple Doppler Radar Workshop are summarized by a series of six papers. Part I of this series briefly reviews the history of multiple Doppler experimentation, fundamental concepts of Doppler signal theory, and organization and objectives of the Workshop. Invited presentations by dynamicists and cloud physicists are also summarized.Experimental design and procedures (Part II) are shown to be of critical importance. Well-defined and limited experimental objectives are necessary in view of technological limitations. Specified radar scanning procedures that balance temporal and spatial resolution considerations are discussed in detail. Improved siting for suppression of ground clutter as well as scanning procedures to minimize errors at echo boundaries are discussed. The need for accelerated research using numerically simulated proxy data sets is emphasized.New technology to eliminate various sampling limitations is cited as an eventual solution to many current problems in Part III. Ground clutter contamination may be curtailed by means of full spectral processing, digital filters in real time, and/or variable pulse repetition frequency. Range and velocity ambiguities also may be minimized by various pulsing options as well as random phase transmission. Sidelobe contamination can be reduced through improvements in radomes, illumination patterns, and antenna feed types. Radar volume-scan time can be sharply reduced by means of wideband transmission, phased array antennas, multiple beam antennas, and frequency agility.Part IV deals with synthesis of data from several radars in the context of scientific requirements in cumulus clouds, widespread precipitation, and severe convective storms. The important temporal and spatial scales are examined together with the accuracy required for vertical air motion in each phenomenon. Factors that introduce errors in the vertical velocity field are identified and synthesis techniques are discussed separately for

Imaging By Ultrasound

PubMed Central

Kidney, Maria R.

1986-01-01

Imaging by ultrasound has dramatically changed the investigation and management of many clinical problems. It is useful in many different parts of the body. In this brief discussion, the following topics are considered: hepatic lesions, bleeding in early pregnancy, gynecological pathology (adnexal lesions), aortic aneurysms, thyroid nodules and scrotal masses. The usefulness of duplex carotid sonography, which combines ultrasonic imaging and Doppler studies, is also discussed. Other topics (gallstones, biliary obstruction, renal calculi, hydronephrosis) are discussed in the appropriate sections. ImagesFigure 1Figure 2Figure 3Figure 4 PMID:21267202

Medical Imaging with Ultrasound: Some Basic Physics.

ERIC Educational Resources Information Center

Gosling, R.

1989-01-01

Discussed are medical applications of ultrasound. The physics of the wave nature of ultrasound including its propagation and production, return by the body, spatial and contrast resolution, attenuation, image formation using pulsed echo ultrasound techniques, measurement of velocity and duplex scanning are described. (YP)

Tissue ablation accelerated by peripheral scanning mode with high-intensity focused ultrasound: a study on isolated porcine liver perfusion.

PubMed

Bu, Rui; Yin, Li; Yang, Han; Wang, Qi; Wu, Feng; Zou, Jian Zhong

2013-08-01

The aims of this study were to investigate the feasibility of accelerated tissue ablation using a peripheral scanning mode with high-intensity focused ultrasound (HIFU) and to explore the effect of flow rate on total energy consumption of the target tissues. Using a model of isolated porcine liver perfusion via the portal vein and hepatic artery, we conducted a scanning protocol along the periphery of the target tissues using linear-scanned HIFU to carefully adjust the varying focal depth, generator power, scanning velocity and line-by-line interval over the entire ablation range. Porcine livers were divided into four ablation groups: group 1, n = 12, with dual-vessel perfusion; group 2, n = 11, with portal vein perfusion alone; group 3, n = 10, with hepatic artery perfusion alone; and group 4, n = 11, control group with no-flow perfusion. The samples were cut open consecutively at a thickness of 3 mm, and the actual ablation ranges were calculated along the periphery of the target tissues after triphenyl tetrazolium chloride staining. Total energy consumption was calculated as the sum of the energy requirements at various focal depths in each group. On the basis of the pre-supposed scanning protocol, the peripheral region of the target tissue formed a complete coagulation necrosis barrier in each group with varying dose combinations, and the volume of the peripheral necrotic area did not differ significantly among the four groups (p > 0.05). Furthermore, total energy consumption in each group significantly decreased with the corresponding decrease in flow rate (p < 0.01). This study revealed that the complete peripheral necrosis barrier within the target tissues can defined using linear-scanned HIFU in an isolated porcine liver perfusion model. Additionally, the flow rate in the major hepatic vessels may play an important role in the use of the peripheral ablation mode, and this novel mode of ablation may enhance the therapeutic efficacy and tolerability of the

Semiquantitative Evaluation of Extrasynovial Soft Tissue Inflammation in the Shoulders of Patients with Polymyalgia Rheumatica and Elderly-Onset Rheumatoid Arthritis by Power Doppler Ultrasound.

PubMed

Suzuki, Takeshi; Yoshida, Ryochi; Okamoto, Akiko; Seri, Yu

2017-01-01

Objectives . To develop a scoring system for evaluating the extrasynovial soft tissue inflammation of the shoulders in patients with polymyalgia rheumatica (PMR) and elderly-onset rheumatoid arthritis with PMR-like onset (pm-EORA) using ultrasound. Methods . We analyzed stored power Doppler (PD) images obtained by the pretreatment examination of 15 PMR patients and 15 pm-EORA patients. A semiquantitative scoring system for evaluating the severity of PD signals adjacent to the anterior aspect of the subscapularis tendon was designed. Results . A four-point scale scoring for the hyperemia on the subscapularis tendon was proposed as follows in brief: 0 = absent or minimal flow, 1 = single vessel dots or short linear-shape signals, 2 = long linear-shape signals or short zone-shape signals, or 3 = long zone-shape signals. This scoring system showed good intra- and interobserver reliability and good correlation to quantitative pixel-counting evaluation. By using it, we demonstrated that inflammation in PMR is dominantly localized in extrasynovial soft tissue as compared with pm-EORA. Conclusions . We proposed a reliable semiquantitative scoring system using ultrasound for the evaluation of extrasynovial soft tissue inflammation of the shoulders in patients with both PMR and pm-EORA. This system is simple to use and can be utilized in future investigations.

[Ultrasound duplex scanning of head and neck vessels with the aim of preoperational preparation of the patients with inherent microtia of the III degree].

PubMed

Chkadua, T Z; Kuz'mina, I V; Ramazanova, Iu I

2010-01-01

For surgical treatment of patients with inherent microtia of the III degree we use one stage method of otoplasty with silicone implant and parietotemporal fascial flap. In order to receive most full picture of the status of superficial temporal artery and its branches the additional diagnostic study is necessary. Method of ultrasound duplex scanning let to study any vessel in real time regimen under monitor screen control. Received by us results of ultrasound duplex scanning of superficial temporal artery branches in patients with inherent microtia of the III degree let us to conclude about the status of the vessel wall, to determine diameter and vessel occlusion, to evaluate and measure blood flow parameters. It is diagnostically necessary criteria for answering the question about flap vitality and in such a way let to avoid possible complications.

Non-contact photoacoustic tomography with a laser Doppler vibrometer

NASA Astrophysics Data System (ADS)

Xu, Guan; Wang, Cheng; Feng, Ting; Oliver, David E.; Wang, Xueding

2014-03-01

Most concurrent photoacoustic tomography systems are based on traditional ultrasound measurement regime, which requires the contact or acoustic coupling material between the biological tissue and the ultrasound transducer. This study investigates the feasibility of non-contact measurement of photacoustic signals generated inside biomedical tissues by observing the vibrations at the surface of the tissues with a commercial laser Doppler vibrometer. The vibrometer with 0- 2MHz measurement bandwidth and 5 MHz sampling frequency was integrated to a conventional rotational PAT data acquisition system. The data acquisition of the vibrometer was synchronized to the laser illumination from an Nd:YAG laser with output at 532nm. The laser energy was tuned to 17.5mJ per square centimeter. The PA signals were acquired at 120 angular locations uniformly distributed around the scanned objects. The frequency response of the measurement system was first calibrated. 2-inch-diamater cylindrical phantoms containing small rubber plates and biological tissues were afterwards imaged. The phantoms were made from 5% intralipid solution in 10% porcine gelatin to simulate the light scattering in biological tissue and to backscatter the measurement laser from the vibrometer. Time-domain backprojection method was used for the image reconstruction. Experiments with real-tissue phantoms show that with laser illumination of 17.5 mJ/cm2 at 532 nm, the non-contact photoacoustic (PA) imaging system with 15dB detection bandwidth of 2.5 MHz can resolve spherical optical inclusions with dimension of 500μm and multi-layered structure with optical contrast in strongly scattering medium. The experiment results prompt the potential implementation of the non-contact PAT to achieve "photoacoustic camera".

4D microvascular imaging based on ultrafast Doppler tomography.

PubMed

Demené, Charlie; Tiran, Elodie; Sieu, Lim-Anna; Bergel, Antoine; Gennisson, Jean Luc; Pernot, Mathieu; Deffieux, Thomas; Cohen, Ivan; Tanter, Mickael

2016-02-15

4D ultrasound microvascular imaging was demonstrated by applying ultrafast Doppler tomography (UFD-T) to the imaging of brain hemodynamics in rodents. In vivo real-time imaging of the rat brain was performed using ultrasonic plane wave transmissions at very high frame rates (18,000 frames per second). Such ultrafast frame rates allow for highly sensitive and wide-field-of-view 2D Doppler imaging of blood vessels far beyond conventional ultrasonography. Voxel anisotropy (100 μm × 100 μm × 500 μm) was corrected for by using a tomographic approach, which consisted of ultrafast acquisitions repeated for different imaging plane orientations over multiple cardiac cycles. UFT-D allows for 4D dynamic microvascular imaging of deep-seated vasculature (up to 20 mm) with a very high 4D resolution (respectively 100 μm × 100 μm × 100 μm and 10 ms) and high sensitivity to flow in small vessels (>1 mm/s) for a whole-brain imaging technique without requiring any contrast agent. 4D ultrasound microvascular imaging in vivo could become a valuable tool for the study of brain hemodynamics, such as cerebral flow autoregulation or vascular remodeling after ischemic stroke recovery, and, more generally, tumor vasculature response to therapeutic treatment. Copyright © 2015 Elsevier Inc. All rights reserved.

Two-dimensional multi-frequency imaging of a tumor inclusion in a homogeneous breast phantom using the harmonic motion Doppler imaging method.

PubMed

Tafreshi, Azadeh Kamali; Top, Can Barış; Gençer, Nevzat Güneri

2017-06-21

Harmonic motion microwave Doppler imaging (HMMDI) is a novel imaging modality for imaging the coupled electrical and mechanical properties of body tissues. In this paper, we used two experimental systems with different receiver configurations to obtain HMMDI images from tissue-mimicking phantoms at multiple vibration frequencies between 15 Hz and 35 Hz. In the first system, we used a spectrum analyzer to obtain the Doppler data in the frequency domain, while in the second one, we used a homodyne receiver that was designed to acquire time-domain data. The developed phantoms mimicked the elastic and dielectric properties of breast fat tissue, and included a [Formula: see text] mm cylindrical inclusion representing the tumor. A focused ultrasound probe was mechanically scanned in two lateral dimensions to obtain two-dimensional HMMDI images of the phantoms. The inclusions were resolved inside the fat phantom using both experimental setups. The image resolution increased with increasing vibration frequency. The designed receiver showed higher sensitivity than the spectrum analyzer measurements. The results also showed that time-domain data acquisition should be used to fully exploit the potential of the HMMDI method.

Two-dimensional multi-frequency imaging of a tumor inclusion in a homogeneous breast phantom using the harmonic motion Doppler imaging method

NASA Astrophysics Data System (ADS)

Kamali Tafreshi, Azadeh; Barış Top, Can; Güneri Gençer, Nevzat

2017-06-01

Harmonic motion microwave Doppler imaging (HMMDI) is a novel imaging modality for imaging the coupled electrical and mechanical properties of body tissues. In this paper, we used two experimental systems with different receiver configurations to obtain HMMDI images from tissue-mimicking phantoms at multiple vibration frequencies between 15 Hz and 35 Hz. In the first system, we used a spectrum analyzer to obtain the Doppler data in the frequency domain, while in the second one, we used a homodyne receiver that was designed to acquire time-domain data. The developed phantoms mimicked the elastic and dielectric properties of breast fat tissue, and included a 14~\\text{mm}× 9 mm cylindrical inclusion representing the tumor. A focused ultrasound probe was mechanically scanned in two lateral dimensions to obtain two-dimensional HMMDI images of the phantoms. The inclusions were resolved inside the fat phantom using both experimental setups. The image resolution increased with increasing vibration frequency. The designed receiver showed higher sensitivity than the spectrum analyzer measurements. The results also showed that time-domain data acquisition should be used to fully exploit the potential of the HMMDI method.

Vector Doppler: spatial sampling analysis and presentation techniques for real-time systems

NASA Astrophysics Data System (ADS)

Capineri, Lorenzo; Scabia, Marco; Masotti, Leonardo F.

2001-05-01

The aim of the vector Doppler (VD) technique is the quantitative reconstruction of a velocity field independently of the ultrasonic probe axis to flow angle. In particular vector Doppler is interesting for studying vascular pathologies related to complex blood flow conditions. Clinical applications require a real-time operating mode and the capability to perform Doppler measurements over a defined volume. The combination of these two characteristics produces a real-time vector velocity map. In previous works the authors investigated the theory of pulsed wave (PW) vector Doppler and developed an experimental system capable of producing off-line 3D vector velocity maps. Afterwards, for producing dynamic velocity vector maps, we realized a new 2D vector Doppler system based on a modified commercial echograph. The measurement and presentation of a vector velocity field requires a correct spatial sampling that must satisfy the Shannon criterion. In this work we tackled this problem, establishing a relationship between sampling steps and scanning system characteristics. Another problem posed by the vector Doppler technique is the data representation in real-time that should be easy to interpret for the physician. With this in mine we attempted a multimedia solution that uses both interpolated images and sound to represent the information of the measured vector velocity map. These presentation techniques were experimented for real-time scanning on flow phantoms and preliminary measurements in vivo on a human carotid artery.

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.

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.

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.

Noninvasive treatment of deep venous thrombosis using pulsed ultrasound cavitation therapy (histotripsy) in a porcine model.

PubMed

Maxwell, Adam D; Owens, Gabe; Gurm, Hitinder S; Ives, Kimberly; Myers, Daniel D; Xu, Zhen

2011-03-01

This study evaluated histotripsy as a noninvasive, image-guided method of thrombolysis in a porcine model of deep vein thrombosis. Histotripsy therapy uses short, high-intensity, focused ultrasound pulses to cause mechanical breakdown of targeted soft tissue by acoustic cavitation, which is guided by real-time ultrasound imaging. This is an in vivo feasibility study of histotripsy thrombolysis. Acute thrombi were formed in the femoral vein of juvenile pigs weighing 30-40 kg by balloon occlusion with two catheters and thrombin infusion. A 10-cm-diameter 1-MHz focused transducer was used for therapy. An 8-MHz ultrasound imager was used to align the clot with the therapy focus. Therapy consisted of five cycle pulses delivered at a rate of 1 kHz and peak negative pressure between 14 and 19 MPa. The focus was scanned along the long axis of the vessel to treat the entire visible clot during ultrasound exposure. The targeted region identified by a hyperechoic cavitation bubble cloud was visualized via ultrasound during treatment. Thrombus breakdown was apparent as a decrease in echogenicity within the vessel in 10 of 12 cases and in 7 cases improved flow through the vein as measured by color Doppler. Vessel histology found denudation of vascular endothelium and small pockets of hemorrhage in the vessel adventitia and underlying muscle and fatty tissue, but perforation of the vessel wall was never observed. The results indicate histotripsy has potential for development as a noninvasive treatment for deep vein thrombosis. Copyright © 2011 SIR. Published by Elsevier Inc. All rights reserved.

Comparative study of lesions created by high-intensity focused ultrasound using sequential discrete and continuous scanning strategies.

PubMed

Fan, Tingbo; Liu, Zhenbo; Zhang, Dong; Tang, Mengxing

2013-03-01

Lesion formation and temperature distribution induced by high-intensity focused ultrasound (HIFU) were investigated both numerically and experimentally via two energy-delivering strategies, i.e., sequential discrete and continuous scanning modes. Simulations were presented based on the combination of Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation and bioheat equation. Measurements were performed on tissue-mimicking phantoms sonicated by a 1.12-MHz single-element focused transducer working at an acoustic power of 75 W. Both the simulated and experimental results show that, in the sequential discrete mode, obvious saw-tooth-like contours could be observed for the peak temperature distribution and the lesion boundaries, with the increasing interval space between two adjacent exposure points. In the continuous scanning mode, more uniform peak temperature distributions and lesion boundaries would be produced, and the peak temperature values would decrease significantly with the increasing scanning speed. In addition, compared to the sequential discrete mode, the continuous scanning mode could achieve higher treatment efficiency (lesion area generated per second) with a lower peak temperature. The present studies suggest that the peak temperature and tissue lesion resulting from the HIFU exposure could be controlled by adjusting the transducer scanning speed, which is important for improving the HIFU treatment efficiency.

Ultrasound for fetal assessment in early pregnancy

PubMed Central

Whitworth, Melissa; Bricker, Leanne; Neilson, James P; Dowswell, Therese

2014-01-01

Background Diagnostic ultrasound is a sophisticated electronic technology, which utilises pulses of high frequency sound to produce an image. Diagnostic ultrasound examination may be employed in a variety of specific circumstances during pregnancy such as after clinical complications, or where there are concerns about fetal growth. Because adverse outcomes may also occur in pregnancies without clear risk factors, assumptions have been made that routine ultrasound in all pregnancies will prove beneficial by enabling earlier detection and improved management of pregnancy complications. Routine screening may be planned for early pregnancy, late gestation, or both. The focus of this review is routine early pregnancy ultrasound. Objectives To assess whether routine early pregnancy ultrasound for fetal assessment (i.e. its use as a screening technique) influences the diagnosis of fetal malformations, multiple pregnancies, the rate of clinical interventions, and the incidence of adverse fetal outcome when compared with the selective use of early pregnancy ultrasound (for specific indications). Search methods We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (September 2009). Selection criteria Published, unpublished, and ongoing randomised controlled trials that compared outcomes in women who experienced routine versus selective early pregnancy ultrasound (i.e. less than 24 weeks’ gestation). We have included quasi-randomised trials. Data collection and analysis Two review authors independently extracted data for each included study. We used the Review Manager software to enter and analyse data. Main results Routine/revealed ultrasound versus selective ultrasound/concealed: 11 trials including 37505 women. Ultrasound for fetal assessment in early pregnancy reduces the failure to detect multiple pregnancy by 24 weeks’ gestation (risk ratio (RR) 0.07, 95% confidence interval (CI) 0.03 to 0.17). Routine scan is associated with a reduction in

Clinical utility of third-trimester uterine artery Doppler in the prediction of brain hemodynamic deterioration and adverse perinatal outcome in small-for-gestational-age fetuses.

PubMed

Cruz-Martinez, R; Savchev, S; Cruz-Lemini, M; Mendez, A; Gratacos, E; Figueras, F

2015-03-01

To assess the clinical value of third-trimester uterine artery (UtA) Doppler ultrasound in the prediction of hemodynamic deterioration and adverse perinatal outcome in term small-for-gestational-age (SGA) fetuses. UtA Doppler parameters, cerebroplacental ratio (CPR) and fetal middle cerebral artery (MCA) pulsatility index (PI) were evaluated weekly, starting from the time of SGA diagnosis until 24 h before induction of labor, in a cohort of 327 SGA fetuses with normal umbilical artery PI (< 95th centile), delivered at > 37 weeks' gestation. Differences in the sequence of CPR and MCA-PI changes < 5th centile, between the group with normal UtA Doppler indices at diagnosis and those with abnormal UtA indices, were analyzed by survival analysis. In addition, the use of UtA Doppler value, alone or in combination with a brain Doppler scan before delivery, to predict the risk of Cesarean section, Cesarean section for non-reassuring fetal status (NRFS), neonatal acidosis and neonatal hospitalization was evaluated by logistic regression analysis, adjusted for gestational age at birth and birth-weight percentile. Abnormal UtA Doppler at diagnosis of SGA was associated with a higher risk of developing abnormal brain Doppler indices before induction of labor than in those with a normal UtA at diagnosis (62.7% vs 34.6%, respectively; P < 0.01). Compared to those with normal UtA Doppler indices, those with abnormal UtA Doppler findings were associated with a higher risk of intrapartum Cesarean section (52.2% vs 37.3%, respectively; P = 0.03), Cesarean section for NRFS (35.8% vs 23.1%, respectively; P = 0.03), neonatal acidosis (10.4% vs 7.7%, respectively; P = 0.47) and neonatal hospitalization (23.9% vs 16.5%, respectively; P = 0.16). Logistic regression analysis indicated that UtA Doppler findings were not significantly associated with adverse perinatal outcome independent of brain Doppler findings. UtA Doppler indices predict adverse perinatal

Imaging in gynecological disease (9): clinical and ultrasound characteristics of tubal cancer.

PubMed

Ludovisi, M; De Blasis, I; Virgilio, B; Fischerova, D; Franchi, D; Pascual, M A; Savelli, L; Epstein, E; Van Holsbeke, C; Guerriero, S; Czekierdowski, A; Zannoni, G; Scambia, G; Jurkovic, D; Rossi, A; Timmerman, D; Valentin, L; Testa, A C

2014-03-01

To describe clinical history and ultrasound findings in patients with tubal carcinoma. Patients with a histological diagnosis of tubal cancer who had undergone preoperative ultrasound examination were identified from the databases of 13 ultrasound centers. The tumors were described by the principal investigator at each contributing center on the basis of ultrasound images, ultrasound reports and research protocols (when applicable) using the terms and definitions of the International Ovarian Tumor Analysis (IOTA) group. In addition, three authors reviewed together all available digital ultrasound images and described them using subjective evaluation of gray-scale and color Doppler ultrasound findings. We identified 79 women with a histological diagnosis of primary tubal cancer, 70 of whom (89%) had serous carcinomas and 46 (58%) of whom presented at FIGO stage III. Forty-nine (62%) women were asymptomatic (incidental finding), whilst the remaining 30 complained of abdominal bloating or pain. Fifty-three (67%) tumors were described as solid at ultrasound examination, 14 (18%) as multilocular solid, 10 (13%) as unilocular solid and two (3%) as unilocular. No tumor was described as a multilocular mass. Most tumors (70/79, 89%) were moderately or very well vascularized on color or power Doppler ultrasound. Normal ovarian tissue was identified adjacent to the tumor in 51% (39/77) of cases. Three types of ultrasound appearance were identified as being typical of tubal carcinoma using pattern recognition: a sausage-shaped cystic structure with solid tissue protruding into it like a papillary projection (11/62, 18%); a sausage-shaped cystic structure with a large solid component filling part of the cyst cavity (13/62, 21%); an ovoid or oblong completely solid mass (36/62, 58%). A well vascularized ovoid or sausage-shaped structure, either completely solid or with large solid component(s) in the pelvis, should raise the suspicion of tubal cancer, especially if normal

Conjugating precision and acquisition time in a Doppler broadening regime by interleaved frequency-agile rapid-scanning cavity ring-down spectroscopy.

PubMed

Gotti, Riccardo; Gatti, Davide; Masłowski, Piotr; Lamperti, Marco; Belmonte, Michele; Laporta, Paolo; Marangoni, Marco

2017-10-07

We propose a novel approach to cavity-ring-down-spectroscopy (CRDS) in which spectra acquired with a frequency-agile rapid-scanning (FARS) scheme, i.e., with a laser sideband stepped across the modes of a high-finesse cavity, are interleaved with one another by a sub-millisecond readjustment of the cavity length. This brings to time acquisitions below 20 s for few-GHz-wide spectra composed of a very high number of spectral points, typically 3200. Thanks to the signal-to-noise ratio easily in excess of 10 000, each FARS-CRDS spectrum is shown to be sufficient to determine the line-centre frequency of a Doppler broadened line with a precision of 2 parts over 10 11 , thus very close to that of sub-Doppler regimes and in a few-seconds time scale. The referencing of the probe laser to a frequency comb provides absolute accuracy and long-term reproducibility to the spectrometer and makes it a powerful tool for precision spectroscopy and line-shape analysis. The experimental approach is discussed in detail together with experimental precision and accuracy tests on the (30 012) ← (00 001) P12e line of CO 2 at ∼1.57 μm.

Reliability and Clinical Correlation of Transcranial Doppler Ultrasound in Sturge-Weber Syndrome.

PubMed

Offermann, Elizabeth A; Sreenivasan, Aditya; DeJong, M Robert; Lin, Doris D M; McCulloch, Charles E; Chung, Melissa G; Comi, Anne M

2017-09-01

The reproducibility of transcranial Doppler (TCD) ultrasound measurements in Sturge-Weber syndrome (SWS) and TCD's ability to predict neurological progression is unknown. In 14 individuals with SWS, TCD measured mean flow velocity, pulsatility index, peak systolic velocity, and end-diastolic velocity in the middle, posterior, and anterior cerebral arteries of the affected and unaffected hemisphere. TCD was performed either once (n = 5) or twice in one day (n = 9). We assessed the reproducibility of the measurements performed twice on the same day on subjects and compared the TCD measurements to previously published age-matched controls. Clinically obtained neuroimaging was scored for extent and severity of SWS brain involvement. Patients were prospectively assigned SWS neuroscores. Middle cerebral artery velocity (r = 0.79, P = 0.04, n = 7), posterior cerebral artery velocity (r = 0.90, P = 0.04, n = 5), and anterior cerebral artery pulsatility index (r = 0.82, P = 0.02, n = 7) were reproducible TCD measurements comparing same-day percent side-to-side differences. In subjects with SWS, affected and unaffected mean peak systolic velocity and end-diastolic velocity in the middle, posterior, and anterior cerebral arteries were globally lower compared with age-matched control subjects. Subjects with the lowest affected middle cerebral artery velocity had the greatest worsening in the total neurological score between time 1 and 2 (r = -0.73, P = 0.04, n = 8) and the most severe magnetic resonance imaging involvement of the affected frontal lobe (r = -0.82, P = 0.007, n = 9). TCD may be a reliable measure with potential clinical value, indicating that blood flow may be globally decreased in SWS patients with unilateral brain involvement. Copyright © 2017. Published by Elsevier Inc.

Virtual Ultrasound Guidance for Inexperienced Operators

NASA Technical Reports Server (NTRS)

Caine, Timothy; Martin, David

2012-01-01

Medical ultrasound or echocardiographic studies are highly operator-dependent and generally require lengthy training and internship to perfect. To obtain quality echocardiographic images in remote environments, such as on-orbit, remote guidance of studies has been employed. This technique involves minimal training for the user, coupled with remote guidance from an expert. When real-time communication or expert guidance is not available, a more autonomous system of guiding an inexperienced operator through an ultrasound study is needed. One example would be missions beyond low Earth orbit in which the time delay inherent with communication will make remote guidance impractical. The Virtual Ultrasound Guidance system is a combination of hardware and software. The hardware portion includes, but is not limited to, video glasses that allow hands-free, full-screen viewing. The glasses also allow the operator a substantial field of view below the glasses to view and operate the ultrasound system. The software is a comprehensive video program designed to guide an inexperienced operator through a detailed ultrasound or echocardiographic study without extensive training or guidance from the ground. The program contains a detailed description using video and audio to demonstrate equipment controls, ergonomics of scanning, study protocol, and scanning guidance, including recovery from sub-optimal images. The components used in the initial validation of the system include an Apple iPod Classic third-generation as the video source, and Myvue video glasses. Initially, the program prompts the operator to power-up the ultrasound and position the patient. The operator would put on the video glasses and attach them to the video source. After turning on both devices and the ultrasound system, the audio-video guidance would then instruct on patient positioning and scanning techniques. A detailed scanning protocol follows with descriptions and reference video of each view along with

Sizing gaseous emboli using Doppler embolic signal intensity.

PubMed

Banahan, Caroline; Hague, James P; Evans, David H; Patel, Rizwan; Ramnarine, Kumar V; Chung, Emma M L

2012-05-01

Extension of transcranial Doppler embolus detection to estimation of bubble size has historically been hindered by difficulties in applying scattering theory to the interpretation of clinical data. This article presents a simplified approach to the sizing of air emboli based on analysis of Doppler embolic signal intensity, by using an approximation to the full scattering theory that can be solved to estimate embolus size. Tests using simulated emboli show that our algorithm is theoretically capable of sizing 90% of "emboli" to within 10% of their true radius. In vitro tests show that 69% of emboli can be sized to within 20% of their true value under ideal conditions, which reduces to 30% of emboli if the beam and vessel are severely misaligned. Our results demonstrate that estimation of bubble size during clinical monitoring could be used to distinguish benign microbubbles from potentially harmful macrobubbles during intraoperative clinical monitoring. Copyright © 2012 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Noncontact measurement of vibration using airborne ultrasound.

PubMed

Mater, O B; Remenieras, J P; Bruneel, C; Roncin, A; Patat, F

1998-01-01

A noncontact ultrasonic method for measuring the surface normal vibration of objects was studied. The instrument consists of a pair of 420 kHz ultrasonic air transducers. One is used to emit ultrasounds toward the moving surface, and the other receives the ultrasound reflected from the object under test. Two effects induce a phase modulation on the received signal. The first effect results from the variation of the round trip time interval tau required for the wavefront to go from the emitter to the moving surface and back to the receiver. This is the Doppler effect directly proportional to the surface displacement. The second effect results from the nonlinear parametric interactions of the ultrasonic beams (forward and backward) with the low frequency sound field emitted in the air by the vibrating surface. This latter phenomenon, which is a volume effect, is proportional to the velocity of the vibrating surface and increases with the distance between the transducers and the surface under test. The relative contribution of the Doppler and parametric effects are evaluated, and both have to be taken into account for ultrasonic interferometry in air.

111-Indium platelet imaging, Doppler spectral analysis and angiography compared in patients with transient cerebral ischaemia.

PubMed

Goldman, M; Leung, J O; Aukland, A; Hawker, R J; Drolc, Z; McCollum, C N

1983-01-01

We have evaluated carotid gamma imaging using 111Indium-labelled platelets in the diagnosis of carotid artery disease and measured the accumulation of labelled platelets on endarterectomy specimens. Autologous 111In labelled platelets were injected in 25 patients with TIA. Gamma images were then taken daily and independently interpreted by two observers. Carotid endarterectomy was performed in 11 patients allowing measurement of the radioactivity on the operative specimen. These results were compared to the findings on angiography and Doppler spectral analysis. All endarterectomy specimens accumulated platelets with the most active equivalent to platelets from 1.8 ml blood. Atheromatous ulcers were more active than stenoses with mean (+/- SEM) activities of 1.12 +/- 0.37 and 0.38 +/- 0.10 respectively. These radioactivity levels were at the threshold of gamma camera resolution in a theoretical model. Both observers agreed that 22 of the 50 carotid bifurcations showed platelet accumulation on gamma imaging. Of the 12 atheromatous ulcers demonstrated by angiography 11 were visualized, but only five of ten stenoses greater than 80% were detected. As Doppler identified all stenoses only one angiographically diseased carotid was not detected by combining ultrasound with platelet scanning. Atherosclerotic arteries accumulate 111In platelets and the more thrombogenic ulcerated plaques are identified more frequently than stenoses. Long-term follow-up is required to establish the clinical relevance of platelet deposition.

In vivo lateral blood flow velocity measurement using speckle size estimation.

PubMed

Xu, Tiantian; Hozan, Mohsen; Bashford, Gregory R

2014-05-01

In previous studies, we proposed blood measurement using speckle size estimation, which estimates the lateral component of blood flow within a single image frame based on the observation that the speckle pattern corresponding to blood reflectors (typically red blood cells) stretches (i.e., is "smeared") if blood flow is in the same direction as the electronically controlled transducer line selection in a 2-D image. In this observational study, the clinical viability of ultrasound blood flow velocity measurement using speckle size estimation was investigated and compared with that of conventional spectral Doppler of carotid artery blood flow data collected from human patients in vivo. Ten patients (six male, four female) were recruited. Right carotid artery blood flow data were collected in an interleaved fashion (alternating Doppler and B-mode A-lines) with an Antares Ultrasound Imaging System and transferred to a PC via the Axius Ultrasound Research Interface. The scanning velocity was 77 cm/s, and a 4-s interval of flow data were collected from each subject to cover three to five complete cardiac cycles. Conventional spectral Doppler data were collected simultaneously to compare with estimates made by speckle size estimation. The results indicate that the peak systolic velocities measured with the two methods are comparable (within ±10%) if the scan velocity is greater than or equal to the flow velocity. When scan velocity is slower than peak systolic velocity, the speckle stretch method asymptotes to the scan velocity. Thus, the speckle stretch method is able to accurately measure pure lateral flow, which conventional Doppler cannot do. In addition, an initial comparison of the speckle size estimation and color Doppler methods with respect to computational complexity and data acquisition time indicated potential time savings in blood flow velocity estimation using speckle size estimation. Further studies are needed for calculation of the speckle stretch method

Evaluation of turbulence measurement techniques from a single Doppler lidar

NASA Astrophysics Data System (ADS)

Bonin, Timothy A.; Choukulkar, Aditya; Brewer, W. Alan; Sandberg, Scott P.; Weickmann, Ann M.; Pichugina, Yelena L.; Banta, Robert M.; Oncley, Steven P.; Wolfe, Daniel E.

2017-08-01

Measurements of turbulence are essential to understand and quantify the transport and dispersal of heat, moisture, momentum, and trace gases within the planetary boundary layer (PBL). Through the years, various techniques to measure turbulence using Doppler lidar observations have been proposed. However, the accuracy of these measurements has rarely been validated against trusted in situ instrumentation. Herein, data from the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) are used to verify Doppler lidar turbulence profiles through comparison with sonic anemometer measurements. For 17 days at the end of the experiment, a single scanning Doppler lidar continuously cycled through different turbulence measurement strategies: velocity-azimuth display (VAD), six-beam scans, and range-height indicators (RHIs) with a vertical stare.Measurements of turbulence kinetic energy (TKE), turbulence intensity, and stress velocity from these techniques are compared with sonic anemometer measurements at six heights on a 300 m tower. The six-beam technique is found to generally measure turbulence kinetic energy and turbulence intensity the most accurately at all heights (r2 ≈ 0.78), showing little bias in its observations (slope of ≈ 0. 95). Turbulence measurements from the velocity-azimuth display method tended to be biased low near the surface, as large eddies were not captured by the scan. None of the methods evaluated were able to consistently accurately measure the shear velocity (r2 = 0.15-0.17). Each of the scanning strategies assessed had its own strengths and limitations that need to be considered when selecting the method used in future experiments.

Ultrasound in differential diagnosis of periapical radiolucencies: A radiohistopathological study

PubMed Central

Khambete, Neha; Kumar, Rahul

2015-01-01

Objectives: To evaluate the efficacy of ultrasound in differential diagnosis of periapical radiolucencies. Materials and Methods: Ten patients aged between 19 years and 40 years with periapical lesions associated with anterior maxillary or mandibular teeth were selected and consented for the study. Pre-operative periapical radiographs were obtained. Measurements and provisional diagnoses of the apical areas were made by two specialist observers on two separate occasions. Preoperative ultrasound examinations with Doppler flowmetry were then performed and the images assessed by two specialist observers for the size, contents, vascular supply and a provisional diagnosis made as to whether the lesion was a cyst or granuloma. Endodontic surgery was performed including curettage of the apical tissues to enable histopathological investigation, which provided the gold standard diagnosis. All measurements and findings were compared and statistically analyzed. Results: Total 10 lesions were identified in 10 patients. On periapical radiographs, lesions were readily identified but observers were unable to differentiate granuloma from cyst using either modality. Where sufficient buccal cortical bone had been resorbed, ultrasound imaging was simple but underestimated the size of the lesions compared with periapical radiographs. In all cases, the ultrasound diagnosis agreed with the histopathological gold standard. Conclusion: Ultrasonography (USG) can provide accurate information about the nature of intraosseous lesions of the jaws before any surgical procedure. It is proposed that USG with Doppler flowmetry can provide an additional diagnostic tool without invasive surgery, where treatment option is nonsurgical. PMID:25657525

Anterior segment biometry with 2 imaging technologies: very-high-frequency ultrasound scanning versus optical coherence tomography.

PubMed

Piñero, David P; Plaza, Ana Belén; Alió, Jorge L

2008-01-01

To determine the interchangeability of 2 anterior segment imaging systems: a very-high-frequency (VHF) ultrasound scanning system (Artemis 2, Ultralink LLC) and an optical coherence tomography (OCT) system (Visante, Zeiss). Vissum Instituto Oftalmologico de Alicante, Alicante, Spain. This study comprised 20 eyes without pathology or previous surgery. The anterior chamber depth (ACD), central corneal thickness (CCT), angle-to-angle distance (ATA), and the iridocorneal angle size (IAS) at the 0-degree and 180-degree positions were measured with 2 imaging techniques: VHF ultrasound scanning and OCT. Analysis of agreement and interchangeability was performed by the Bland and Altman method. In addition, each measurement was performed 3 times consecutively to determine intrasession repeatability by means of the coefficient of variation (CV) and the intraclass correlation coefficient (ICC). No statistically significant differences were found between imaging techniques in ACD, CCT, or ATA (P>.40). The ranges of agreement were 0.20 mm, 16.11 mum, and 0.80 mm for ACD, CCT, and ATA, respectively. Regarding IAS, no statistically significant differences were found in the nasal (P = .78) or temporal (P = .63) measurements between devices. However, the range of agreement for nasal (14.3 degrees) and temporal (14.90 degrees) values was relevant, indicating the 2 techniques cannot be used interchangeably for IAS measurement. Excellent intrasession repeatability scores were obtained (CV and ICC). The Artemis 2 and the Visante OCT systems provide equivalent and repeatable measurements of the ACD, CCT, and ATA and can be used interchangeably for these purposes.

Ultrasound: medical imaging and beyond (an invited review).

PubMed

Azhari, Haim

2012-09-01

Medical applications of ultrasound were first investigated about seventy years ago. It has rapidly evolved since then, becoming an essential tool in medical imaging. Ultrasound ability to provide real time images with frame rates exceeding several hundred frames per second allows one to view rapid anatomical changes as well as to guide minimal invasive procedures. By, combining Doppler techniques with anatomical images ultrasound provides real time quantitative flow information as well. It is portable, versatile, cost effective and considered sufficiently hazardless to monitor pregnancy. Moreover, ultrasound has the unique capacity to offer therapeutic capabilities in addition to its outstanding imaging abilities. It can be used for physiotherapy, lithotripsy, and thermal ablation, and recent studies have demonstrated its usefulness in drug delivery, gene therapy and molecular imaging. The purpose of this article is to provide an introductory review of the field covering briefly topics from basic physics through current imaging methods to therapeutic applications.

Ultrasound biomicroscopy in mouse cardiovascular development

NASA Astrophysics Data System (ADS)

Turnbull, Daniel H.

2004-05-01

The mouse is the preferred animal model for studying mammalian cardiovascular development and many human congenital heart diseases. Ultrasound biomicroscopy (UBM), utilizing high-frequency (40-50-MHz) ultrasound, is uniquely capable of providing in vivo, real-time microimaging and Doppler blood velocity measurements in mouse embryos and neonates. UBM analyses of normal and abnormal mouse cardiovascular function will be described to illustrate the power of this microimaging approach. In particular, real-time UBM images have been used to analyze dimensional changes in the mouse heart from embryonic to neonatal stages. UBM-Doppler has been used recently to examine the precise timing of onset of a functional circulation in early-stage mouse embryos, from the first detectable cardiac contractions. In other experiments, blood velocity waveforms have been analyzed to characterize the functional phenotype of mutant mouse embryos having defects in cardiac valve formation. Finally, UBM has been developed for real-time, in utero image-guided injection of mouse embryos, enabling cell transplantation and genetic gain-of-function experiments with transfected cells and retroviruses. In summary, UBM provides a unique and powerful approach for in vivo analysis and image-guided manipulation in normal and genetically engineered mice, over a wide range of embryonic to neonatal developmental stages.

Microbubble and ultrasound radioenhancement of bladder cancer

PubMed Central

Tran, W T; Iradji, S; Sofroni, E; Giles, A; Eddy, D; Czarnota, G J

2012-01-01

Background: Tumour vasculature is an important component of tumour growth and survival. Recent evidence indicates tumour vasculature also has an important role in tumour radiation response. In this study, we investigated ultrasound and microbubbles to enhance the effects of radiation. Methods: Human bladder cancer HT-1376 xenografts in severe combined immuno-deficient mice were used. Treatments consisted of no, low and high concentrations of microbubbles and radiation doses of 0, 2 and 8 Gy in short-term and longitudinal studies. Acute response was assessed 24 h after treatment and longitudinal studies monitored tumour response weekly up to 28 days using power Doppler ultrasound imaging for a total of 9 conditions (n=90 animals). Results: Quantitative analysis of ultrasound data revealed reduced blood flow with ultrasound-microbubble treatments alone and further when combined with radiation. Tumours treated with microbubbles and radiation revealed enhanced cell death, vascular normalisation and areas of fibrosis. Longitudinal data demonstrated a reduced normalised vascular index and increased tumour cell death in both low and high microbubble concentrations with radiation. Conclusion: Our study demonstrated that ultrasound-mediated microbubble exposure can enhance radiation effects in tumours, and can lead to enhanced tumour cell death. PMID:22790798

Sonographic physical diagnosis 101: teaching senior medical students basic ultrasound scanning skills using a compact ultrasound system.

PubMed

Angtuaco, Teresita L; Hopkins, Robert H; DuBose, Terry J; Bursac, Zoran; Angtuaco, Michael J; Ferris, Ernest J

2007-06-01

This project was designed to test the feasibility of introducing ultrasound to senior medical students as a primary diagnostic tool in the evaluation of patients. Specifically, its aim was to determine if it is possible for medical students untrained in sonography to gain basic competence in performing abdominal ultrasound with limited didactic and hands-on instructions. Registered sonographers provided the students with hands-on instructions on the use of a compact ultrasound system. They were likewise shown how to evaluate specific organs and perform measurements. The results of the student measurements and those obtained by the sonographers were compared. There was close correlation between the results obtained by sonographers and students on both normal and abnormal findings. This supports the concept that medical students can be taught basic ultrasound skills with limited didactic and hands-on instructions with the potential of using these skills in the patient clinics as an adjunct to routine physical diagnosis.

Accuracy, repeatability, and reproducibility of Artemis very high-frequency digital ultrasound arc-scan lateral dimension measurements

PubMed Central

Reinstein, Dan Z.; Archer, Timothy J.; Silverman, Ronald H.; Coleman, D. Jackson

2008-01-01

Purpose To determine the accuracy, repeatability, and reproducibility of measurement of lateral dimensions using the Artemis (Ultralink LLC) very high-frequency (VHF) digital ultrasound (US) arc scanner. Setting London Vision Clinic, London, United Kingdom. Methods A test object was measured first with a micrometer and then with the Artemis arc scanner. Five sets of 10 consecutive B-scans of the test object were performed with the scanner. The test object was removed from the system between each scan set. One expert observer and one newly trained observer separately measured the lateral dimension of the test object. Two-factor analysis of variance was performed. The accuracy was calculated as the average bias of the scan set averages. The repeatability and reproducibility coefficients were calculated. The coefficient of variation (CV) was calculated for repeatability and reproducibility. Results The test object was measured to be 10.80 mm wide. The mean lateral dimension bias was 0.00 mm. The repeatability coefficient was 0.114 mm. The reproducibility coefficient was 0.026 mm. The repeatability CV was 0.38%, and the reproducibility CV was 0.09%. There was no statistically significant variation between observers (P = .0965). There was a statistically significant variation between scan sets (P = .0036) attributed to minor vertical changes in the alignment of the test object between consecutive scan sets. Conclusion The Artemis VHF digital US arc scanner obtained accurate, repeatable, and reproducible measurements of lateral dimensions of the size commonly found in the anterior segment. PMID:17081860

Ultrasound guidance versus anatomical landmarks for internal jugular vein catheterization.

PubMed

Brass, Patrick; Hellmich, Martin; Kolodziej, Laurentius; Schick, Guido; Smith, Andrew F

2015-01-09

Central venous catheters (CVCs) can help with diagnosis and treatment of the critically ill. The catheter may be placed in a large vein in the neck (internal jugular vein), upper chest (subclavian vein) or groin (femoral vein). Whilst this is beneficial overall, inserting the catheter risks arterial puncture and other complications and should be performed with as few attempts as possible. Traditionally, anatomical 'landmarks' on the body surface were used to find the correct place in which to insert catheters, but ultrasound imaging is now available. A Doppler mode is sometimes used to supplement plain 'two-dimensional' ultrasound. The primary objective of this review was to evaluate the effectiveness and safety of two-dimensional (imaging ultrasound (US) or ultrasound Doppler (USD)) guided puncture techniques for insertion of central venous catheters via the internal jugular vein in adults and children. We assessed whether there was a difference in complication rates between traditional landmark-guided and any ultrasound-guided central vein puncture.Our secondary objectives were to assess whether the effect differs between US and USD; whether the effect differs between ultrasound used throughout the puncture ('direct') and ultrasound used only to identify and mark the vein before the start of the puncture procedure (indirect'); and whether the effect differs between different groups of patients or between different levels of experience among those inserting the catheters. We searched the Central Register of Controlled Trials (CENTRAL) (2013, Issue 1), MEDLINE (1966 to 15 January 2013), EMBASE (1966 to 15 January 2013), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to 15 January 2013 ), reference lists of articles, 'grey literature' and dissertations. An additional handsearch focused on intensive care and anaesthesia journals and abstracts and proceedings of scientific meetings. We attempted to identify unpublished or ongoing studies

Role of 3D power Doppler ultrasound in the further characterization of suspicious breast masses.

PubMed

Kupeli, Ali; Kul, Sibel; Eyuboglu, Ilker; Oguz, Sukru; Mungan, Sevdegul

2016-01-01

To investigate effectiveness of vascular indices obtained with 3D power Doppler ultrasound in the further characterization of breast masses and prevention of unnecessary biopsies. Between April 2013 and March 2014, 109 patients (age range, 17-85 years; mean age, 47 years) with 117 radiologically or clinically suspicious breast masses were prospectively evaluated with 3DPDUS before biopsy. Mass volume (MV), vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were calculated using Virtual Organ Computer-aided Analysis (VOCAL) software and they were correlated with the final diagnosis. Cutoff values of vascular indices were determinated and diagnostic efficacy was calculated with receiver operating curve (ROC) analysis. All vascular indices, age of patients and tumor volume were significantly lower in benign masses compared with malignant ones (p<0.001). AUCs were 0.872, 0.867 and 0.789 for VI, VFI and FI, respectively. The diagnostic efficacy of VI (for cutoff 1.1; 83% sensitivity, 82% specificity and 82% accuracy) and VFI (for cutoff 0.4; 80% sensitivity, 83% specificity and 80% accuracy) were significantly higher than FI (for cutoff 33,9; 73% sensitivity, 69% specificity and 71% accuracy). It was found that with the use of vascular indices of 3DPDUS in the further characterization of suspicious breast masses between 24% to 37% of unnecessary biopsies could have been avoided. The vascular indices obtained with 3DPDUS seem reliable in the further characterization of suspicious breast masses and might be used to decrease unnecessary biopsies. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Fetal evaluation for transport by ultrasound performed by air medical teams: A case series.

PubMed

Polk, James D; Merlino, James I; Kovach, Betty L; Mancuso, Charlene; Fallon, William F

2004-01-01

The air medical team has limited options when evaluating the obstetrical patient and assessing fetal health during air transport to a high-risk obstetrical unit. Traditionally, physical examination and a Doppler stethoscope have been used to determine fetal heart rates and movement. However, with the advent of portable ultrasound technology, new information about the mother and child are available to the air medical crew. The Fetal Evaluation for Transport with Ultrasound (FETUS) is a screening examination that consists of an evaluation of the fetal heart rate, position, and movement and general condition of the placenta. The examination can be repeated in flight with no acoustic distortion from rotor noise. The additional information can be advantageous when transport decisions need to be made or when conditions do not allow Doppler stethoscope use.

Angiosonography in suspicious breast lesions with non-diagnostic FNAC: comparison with power Doppler US.

PubMed

Caumo, F; Carbognin, G; Casarin, A; Pinali, L; Vasori, S; D'Onofrio, M; Pozzi Mucelli, R

2006-02-01

The purpose of this study was to evaluate the accuracy of angiosonography in comparison with colour Doppler ultrasound (US) in the discrimination of suspicious breast lesions with nondiagnostic fine-needle aspiration cytology (FNAC). Pre-operative Power Doppler US and angiosonography were prospectively performed in 20 suspicious breast lesions with non-diagnostic FNAC. A second-generation US contrast agent was utilised with a high-frequency transducer and a contrast-specific algorithm (low acoustic pressure CnTI). The enhancement characteristics of all lesions were analysed using qualitative and quantitative parameters obtained from time-intensity curves with the different imaging modalities. The final diagnosis was confirmed at pathology in all cases. Microvessel density (MVD) was assessed in the surgical specimen using CD34. The correct assessment of biological behaviour was achieved in all cases by angiosonography (sensitivity of 100%; specificity of 91%) and colour Doppler US (45% sensitivity; 78% specificity). MVD correlated with the biological behaviour. Angiosonography is more accurate than colour Doppler US in the correct assessment of biological behaviour of suspicious breast lesions.

Robust estimation of fetal heart rate from US Doppler signals

NASA Astrophysics Data System (ADS)

Voicu, Iulian; Girault, Jean-Marc; Roussel, Catherine; Decock, Aliette; Kouame, Denis

2010-01-01

Introduction: In utero, Monitoring of fetal wellbeing or suffering is today an open challenge, due to the high number of clinical parameters to be considered. An automatic monitoring of fetal activity, dedicated for quantifying fetal wellbeing, becomes necessary. For this purpose and in a view to supply an alternative for the Manning test, we used an ultrasound multitransducer multigate Doppler system. One important issue (and first step in our investigation) is the accurate estimation of fetal heart rate (FHR). An estimation of the FHR is obtained by evaluating the autocorrelation function of the Doppler signals for ills and healthiness foetus. However, this estimator is not enough robust since about 20% of FHR are not detected in comparison to a reference system. These non detections are principally due to the fact that the Doppler signal generated by the fetal moving is strongly disturbed by the presence of others several Doppler sources (mother' s moving, pseudo breathing, etc.). By modifying the existing method (autocorrelation method) and by proposing new time and frequency estimators used in the audio' s domain, we reduce to 5% the probability of non-detection of the fetal heart rate. These results are really encouraging and they enable us to plan the use of automatic classification techniques in order to discriminate between healthy and in suffering foetus.

Hazards, risks and safety of diagnostic ultrasound.

PubMed

Duck, Francis A

2008-12-01

The safety of exposure to diagnostic ultrasound is evaluated using a structured approach to risk assessment, based on the acoustic output of present ultrasound scanners. Thermal hazard is described, the magnitude and probability of temperature rise is reviewed, and the severity of harm from any outcome is reviewed. Similar assessments are made separately for acoustic cavitation and gas-body effects, which have previously been considered together. Finally, radiation pressure is considered in a similar manner. In each case, means to minimize the risk are suggested where appropriate. The highest risks are associated with the use of gas-bubble contrast agents. It is concluded that there is a medium risk associated with trans-cranial Doppler use, and that this use of ultrasound deserves more detailed safety review. The risks associated with the current practice of obstetric ultrasound are low. Whilst the severity of radiation pressure as a hazard is low, it is always present. Little is known about any associated cell responses and so the associated risk cannot be evaluated.

Achilles tendon shape and echogenicity on ultrasound among active badminton players.

PubMed

Malliaras, P; Voss, C; Garau, G; Richards, P; Maffulli, N

2012-04-01

The relationship between Achilles tendon ultrasound abnormalities, including a spindle shape and heterogeneous echogenicity, is unclear. This study investigated the relationship between these abnormalities, tendon thickness, Doppler flow and pain. Sixty-one badminton players (122 tendons, 36 men, and 25 women) were recruited. Achilles tendon thickness, shape (spindle, parallel), echogenicity (heterogeneous, homogeneous) and Doppler flow (present or absent) were measured bilaterally with ultrasound. Achilles tendon pain (during or after activity over the last week) and pain and function [Victorian Institute of Sport Achilles Assessment (VISA-A)] were measured. Sixty-eight (56%) tendons were parallel with homogeneous echogenicity (normal), 22 (18%) were spindle shaped with homogeneous echogenicity, 16 (13%) were parallel with heterogeneous echogenicity and 16 (13%) were spindle shaped with heterogeneous echogenicity. Spindle shape was associated with self-reported pain (P<0.05). Heterogeneous echogenicity was associated with lower VISA-A scores than normal tendon (P<0.05). There was an ordinal relationship between normal tendon, parallel and heterogeneous and spindle shaped and heterogeneous tendons with regard to increasing thickness and likelihood of Doppler flow. Heterogeneous echogenicity with a parallel shape may be a physiological phase and may develop into heterogeneous echogenicity with a spindle shape that is more likely to be pathological. © 2010 John Wiley & Sons A/S.

Cross-correlation Doppler global velocimetry (CC-DGV)

NASA Astrophysics Data System (ADS)

Cadel, Daniel R.; Lowe, K. Todd

2015-08-01

A flow velocimetry method, cross-correlation Doppler global velocimetry (CC-DGV), is presented as a robust, simplified, and high dynamic range implementation of the Doppler global/planar Doppler velocimetry technique. A sweep of several gigahertz of the vapor absorption spectrum is used for each velocity sample, with signals acquired from both Doppler-shifted scattered light within the flow and a non-Doppler shifted reference beam. Cross-correlation of these signals yields the Doppler shift between them, averaged over the duration of the scan. With presently available equipment, velocities from 0 ms-1 to over 3000 ms-1 can notionally be measured simultaneously, making the technique ideal for high speed flows. The processing routine is shown to be robust against large changes in the vapor pressure of the iodine cell, benefiting performance of the system in facilities where ambient conditions cannot be easily regulated. Validation of the system was performed with measurements of a model wind turbine blade boundary layer made in a 1.83 m by 1.83 m subsonic wind tunnel for which laser Doppler velocimetry (LDV) measurements were acquired alongside the CC-DGV results. CC-DGV uncertainties of ±1.30 ms-1, ±0.64 ms-1, and ±1.11 ms-1 were determined for the orthogonal stream-wise, transverse-horizontal, and transverse-vertical velocity components, and root-mean-square deviations of 2.77 ms-1 and 1.34 ms-1 from the LDV validation results were observed for Reynolds numbers of 1.5 million and 2 million, respectively. Volumetric mean velocity measurements are also presented for a supersonic jet, with velocity uncertainties of ±4.48 ms-1, ±16.93 ms-1, and ±0.50 ms-1 for the orthogonal components, and self-validation done by collapsing the data with a physical scaling.

Assessment of peripheral skeletal muscle microperfusion in a porcine model of peripheral arterial stenosis by steady-state contrast-enhanced ultrasound and Doppler flow measurement.

PubMed

Naehle, Claas P; Steinberg, Verena A; Schild, Hans; Mommertz, Gottfried

2015-05-01

Noninvasive measurement of peripheral muscle microperfusion could potentially improve diagnosis, management, and treatment of peripheral arterial disease (PAD) and thus improve patient care. Contrast-enhanced ultrasound (CEUS) as a noninvasive diagnostic tool allows quantification of muscle perfusion. Increasing data on bolus technique CEUS reflecting microperfusion are becoming available, but only limited data on steady-state CEUS for assessment of muscle microperfusion are available. Therefore, the aim of this study was to evaluate steady-state CEUS for assessment of peripheral muscle microperfusion in a PAD animal model. In a porcine animal model, peripheral muscle microperfusion was quantified by steady-state CEUS replenishment kinetics (mean transit time [mTT] and wash-in rate [WiR]) of the biceps femoris muscle during intravenous steady-state infusion of INN-sulfur hexafluoride (SonoVue; Bracco, Geneva, Switzerland). In addition, macroperfusion was quantified at the external femoral artery with a Doppler flow probe. Peripheral muscle microperfusion and Doppler flow measurements were performed bilaterally at rest and under adenosine stress (70 μg/kg body weight) before and after unilateral creation of a moderate external iliac artery stenosis. All measurements could be performed completely in 10 pigs. Compared with baseline measurements, peripheral muscle microperfusion decreased significantly during adenosine stress (rest vs adenosine stress: mTT, 7.8 ± 3.3 vs 21.2 ± 17.8 s, P = .0006; WiR, 58.4 ± 38.1 vs 25.3 ± 15.6 arbitrary units [a.u.]/s, P < .0001; Doppler flow, 122.3 ± 31.4 vs 83.6 ± 28.1 mL/min, P = .0067) and after stenosis creation (no stenosis vs stenosis: mTT, 8.1 ± 3.1 vs 29.2 ± 18.0 s, P = .0469; WiR, 53.0 ± 22.7 vs 13.6 ± 8.4 a.u./s, P = .0156; Doppler flow, 124.2 ± 41.8 vs 65.9 ± 40.0 mL/min, P = .0313). After stenosis creation, adenosine stress led to a further significant decrease of peripheral muscle microperfusion but had no

Iodine-filter-based mobile Doppler lidar to make continuous and full-azimuth-scanned wind measurements: data acquisition and analysis system, data retrieval methods, and error analysis.

PubMed

Wang, Zhangjun; Liu, Zhishen; Liu, Liping; Wu, Songhua; Liu, Bingyi; Li, Zhigang; Chu, Xinzhao

2010-12-20

An incoherent Doppler wind lidar based on iodine edge filters has been developed at the Ocean University of China for remote measurements of atmospheric wind fields. The lidar is compact enough to fit in a minivan for mobile deployment. With its sophisticated and user-friendly data acquisition and analysis system (DAAS), this lidar has made a variety of line-of-sight (LOS) wind measurements in different operational modes. Through carefully developed data retrieval procedures, various wind products are provided by the lidar, including wind profile, LOS wind velocities in plan position indicator (PPI) and range height indicator (RHI) modes, and sea surface wind. Data are processed and displayed in real time, and continuous wind measurements have been demonstrated for as many as 16 days. Full-azimuth-scanned wind measurements in PPI mode and full-elevation-scanned wind measurements in RHI mode have been achieved with this lidar. The detection range of LOS wind velocity PPI and RHI reaches 8-10 km at night and 6-8 km during daytime with range resolution of 10 m and temporal resolution of 3 min. In this paper, we introduce the DAAS architecture and describe the data retrieval methods for various operation modes. We present the measurement procedures and results of LOS wind velocities in PPI and RHI scans along with wind profiles obtained by Doppler beam swing. The sea surface wind measured for the sailing competition during the 2008 Beijing Olympics is also presented. The precision and accuracy of wind measurements are estimated through analysis of the random errors associated with photon noise and the systematic errors introduced by the assumptions made in data retrieval. The three assumptions of horizontal homogeneity of atmosphere, close-to-zero vertical wind, and uniform sensitivity are made in order to experimentally determine the zero wind ratio and the measurement sensitivity, which are important factors in LOS wind retrieval. Deviations may occur under certain

[Contrast-enhanced ultrasound in animal models].

PubMed

Paprottka, P M; Zengel, P; Ingrisch, M; Cyran, C C; Eichhorn, M; Reiser, M F; Nikolaou, K; Clevert, D-A

2011-06-01

In the past the detection of tumor perfusion was achieved solely via invasive procedures, such as intravital microscopy or with the help of costly modalities, such as multidetector computed tomography (MDCT), magnetic resonance tomography (MRT) or the combined use of positron emission tomography and computed tomography (PET/CT). Ultrasound offers the non-invasive display of organs without usage of ionizing radiation and it is widely available. However, colour-coded ultrasound and power Doppler do not allow the detection of tumor microcirculation. The introduction of contrast-enhanced ultrasound (CEUS) as well as new high-frequency ultrasound probes made it possible to detect and quantify tumor microcirculation with high resolution. CEUS has been used clinically on human beings for more than 10 years. During the last years different tumor models in experimental animals were used for the establishment of this new technique, e.g. in rats, hamsters and mice. CEUS allows the detection of functional parameters, such as the angiogenetic metabolic status of tissue pretreatment and posttreatment. Further research is required to solve the problems of absolute quantification of these perfusion parameters to allow the comparison of CEUS with other modalities (e.g. MRT and CT).

Assessment of virtual towers performed with scanning wind lidars and Ka-band radars during the XPIA experiment

DOE PAGES

Debnath, Mithu; Iungo, Giacomo Valerio; Brewer, W. Alan; ...

2017-03-29

During the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign, which was carried out at the Boulder Atmospheric Observatory (BAO) in spring 2015, multiple-Doppler scanning strategies were carried out with scanning wind lidars and Ka-band radars. Specifically, step–stare measurements were collected simultaneously with three scanning Doppler lidars, while two scanning Ka-band radars carried out simultaneous range height indicator (RHI) scans. The XPIA experiment provided the unique opportunity to compare directly virtual-tower measurements performed simultaneously with Ka-band radars and Doppler wind lidars. Furthermore, multiple-Doppler measurements were assessed against sonic anemometer data acquired from the meteorological tower (met-tower) present at the BAOmore » site and a lidar wind profiler. As a result, this survey shows that – despite the different technologies, measurement volumes and sampling periods used for the lidar and radar measurements – a very good accuracy is achieved for both remote-sensing techniques for probing horizontal wind speed and wind direction with the virtual-tower scanning technique.« less

Three-dimensional ultrasound features of the polycystic ovary in Chinese women.

PubMed

Lam, P; Raine-Fenning, N; Cheung, L; Haines, C

2009-08-01

To quantify the three-dimensional (3D) ultrasound characteristics of ovaries in Chinese women with polycystic ovarian syndrome (PCOS) and to compare these with previous data on a Caucasian cohort with PCOS. 3D pelvic ultrasound was performed in 40 Chinese women with PCOS and 40 controls. Ovarian volume, stromal volume and echogenicity, and antral follicle count (AFC) were measured and ovarian blood flow was quantified using both 3D power Doppler and two-dimensional (2D) pulsed wave Doppler. These data were compared with previously published data on a Caucasian cohort with PCOS. Compared with controls, women with PCOS had a higher AFC (median (range), 15 (11-30) vs. 5.5 (1-10) per ovary, P < 0.01), ovarian volume (12.32 (8.10-16.16) mL vs. 5.64 (2.62-8.81) mL, P < 0.01) and stromal volume (9.74 (6.44-13.56) mL vs. 4.07 (1.52-6.67) mL, P < 0.01) but were comparable in stromal echogenicity and ovarian blood flow as measured by 3D power Doppler or 2D pulsed wave Doppler indices. However, in comparison with a previously reported Caucasian cohort with PCOS, the ovaries of Chinese women with PCOS had a significantly smaller stromal volume (median (range), 9.74 (6.44-13.56) mL vs. 10.79 (5.65-17.12) mL, P < 0.05), were less echogenic as reflected in a lower mean gray value (22.43 (13.13-35.50) vs. 32.36 (19.35-53.71), P < 0.01), and had reduced ovarian blood flow as reflected in a lower flow index (30.19 (23.32-44.88) vs. 33.54 (21.88-51.65), P < 0.05). Based on 3D ultrasound measurements, Chinese women with PCOS have an increased stromal volume compared with controls. However, their stromal volume, echogenicity and vascularity is significantly lower than that in Caucasian women with PCOS. The possible etiology for these differences is discussed.

Evaluation of arterial digital blood flow using Doppler ultrasonography in healthy dairy cows.

PubMed

Müller, H; Heinrich, M; Mielenz, N; Reese, S; Steiner, A; Starke, A

2017-06-06

Local circulatory disturbances have been implicated in the development of foot disorders in cattle. The goals of this study were to evaluate the suitability of the interdigital artery in the pastern region in both hind limbs using pulsed-wave (PW) Doppler ultrasonography and to investigate quantitative arterial blood flow variables at that site in dairy cows. An Esaote MyLabOne ultrasound machine with a 10-MHz linear transducer was used to assess blood flow in the interdigital artery in the pastern region in both hind limbs of 22 healthy German Holstein cows. The cows originated from three commercial farms and were restrained in a standing hoof trimming chute without sedation. A PW Doppler signal suitable for analysis was obtained in 17 of 22 cows. The blood flow profiles were categorised into four curve types, and the following quantitative variables were measured in three uniform cardiac cycles: vessel diameter, pulse rate, maximum systolic velocity, maximum diastolic velocity, end-diastolic velocity, reverse velocity, maximum time-averaged mean velocity, blood flow rate, resistance index and persistence index. The measurements did not differ among cows from the three farms. Maximum systolic velocity, vessel diameter and pulse rate did not differ but other variables differed significantly among blood flow profiles. Differences in weight-bearing are thought to be responsible for the normal variability of blood flow profiles in healthy cows. The scanning technique used in this report for evaluation of blood flow in the interdigital artery appears suitable for further investigations in healthy and in lame cows.

Transcranial Doppler: Techniques and advanced applications: Part 2

PubMed Central

Sharma, Arvind K.; Bathala, Lokesh; Batra, Amit; Mehndiratta, Man Mohan; Sharma, Vijay K.

2016-01-01

Transcranial Doppler (TCD) is the only diagnostic tool that can provide continuous information about cerebral hemodynamics in real time and over extended periods. In the previous paper (Part 1), we have already presented the basic ultrasound physics pertaining to TCD, insonation methods, and various flow patterns. This article describes various advanced applications of TCD such as detection of right-to-left shunt, emboli monitoring, vasomotor reactivity (VMR), monitoring of vasospasm in subarachnoid hemorrhage (SAH), monitoring of intracranial pressure, its role in stoke prevention in sickle cell disease, and as a supplementary test for confirmation of brain death. PMID:27011639

A 100-200 MHz ultrasound biomicroscope.

PubMed

Knspik, D A; Starkoski, B; Pavlin, C J; Foster, F S

2000-01-01

The development of higher frequency ultrasound imaging systems affords a unique opportunity to visualize living tissue at the microscopic level. This work was undertaken to assess the potential of ultrasound imaging in vivo using the 100-200 MHz range. Spherically focused lithium niobate transducers were fabricated. The properties of a 200 MHz center frequency device are described in detail. This transducer showed good sensitivity with an insertion loss of 18 dB at 200 MHz. Resolution of 14 /spl mu/m in the lateral direction and 12 /spl mu/m in the axial direction was achieved with f/1.14 focusing. A linear mechanical scan system and a scan converter were used to generate B-scan images at a frame rate up to 12 frames per second. System performance in B-mode imaging is limited by frequency dependent attenuation in tissues. An alternative technique, zone-focus image collection, was investigated to extend depth of field. Images of coronary arteries, the eye, and skin are presented along with some preliminary correlations with histology. These results demonstrate the feasibility of ultrasound biomicroscopy In the 100-200 MHz range. Further development of ultrasound backscatter imaging at frequencies up to and above 200 MHz will contribute valuable information about tissue microstructure.